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Objective: The objective was to evaluate factors associated with the long-term durability of outcomes in adult spinal deformity (ASD) patients., Methods: Operative ASD patients fused from at least L1 to the sacrum with baseline (BL) to 5-year (5Y) follow-up were included. Substantial clinical benefit (SCB) in Oswestry Disability Index (ODI), numeric rating scale (NRS)-back, NRS-leg, and Scoliosis Research Society (SRS)-22r scores and physical component score were assessed on the basis of previously published values. Factors were evaluated on the basis of meeting optimal outcomes (OO) at 2 years (2+) and 5 years (5+). Furthermore, 2+ patients were isolated and evaluated on the basis of meeting OO at 5 years (2+5+) or not at 5 years (2+5-). OO were defined as follows: no reoperation, major mechanical failure, proximal junctional failure, and meeting either 1) SCB in terms of ODI score (decrease > 18.8) or 2) ODI < 15 and SRS-22r total > 4.5., Results: In total, 330 ASD patients met the inclusion criteria, with 45.5% meeting SCB for ODI at 2 years, while 46.0% met SCB at 5 years; 79% of those who achieved 2-year (2Y) SCB went on to achieve 5Y SCB. This rate was lower for OO, with 41% achieving 2Y OO (2+), while 37% met 5Y OO (5+) and 80% of 2+ patients had durable outcomes until 5+ (32% of the total cohort). Of the patient factors, frailty was significantly different among groups at 2 years, while comorbidity burden was significantly different at 5 years and the combination thereof differed in those with durable outcomes. Those who regained their level of activity postoperatively had 4 times higher odds of maintaining OO from 2 years to 5 years (p < 0.05). Osteoporosis rates, although equivocal at BL, were higher at the last follow-up in those who met 2Y OO but failed to meet 5Y OO. The odds of achieving OO at 5 years in 2+ patients decreased by 47% for each additional comorbidity and decreased by 74% in those who had lower-extremity paresthesias at BL (both p < 0.05). Controlling for patient factors and BL disability found fewer levels fused, decreased correction of sagittal vertical axis, and increased correction of pelvic incidence-lumbar lordosis mismatch to be predictive of maintaining 2Y OO until 5 years (p < 0.05)., Conclusions: SCB was met in 46% of ASD patients at 5 years. The durability of OO was seen in a third of patients until 5 years postoperatively. Higher rates of medical complications were seen in those who failed to achieve and maintain OO until 5 years. Frailty and comorbidity burden were significant factors associated with the achievement and durability of OO until 5 years.

Objective: Recent debate has arisen between whether to use a three-column osteotomy (3CO) or multilevel low-grade (MLG) techniques to treat severe sagittal malalignment in adult spinal deformity (ASD) surgery. The goal of this study was to compare the outcomes of 3CO and MLG techniques performed in corrective surgeries for ASD., Methods: ASD patients who had a baseline PI-LL > 30° and 2-year follow-up data were included. Patients underwent either 3CO or MLG (thoracolumbar posterior column osteotomies at ≥ 3 levels or anterior lumbar interbody fusion at ≥ 3 levels with no 3CO). The segmental utility ratio was used to assess relative segmental correction (segmental correction divided by overall correction in lordosis divided by the number of thoracolumbar interventions [interbody fusion, thoracolumbar posterior column osteotomies, and 3CO]). The paired t-test was used to assess lordotic distribution by differences in lordosis between adjacent lumbar disc spaces (e.g., L1-2 to L2-3). Multivariate analysis, controlling for age, sex, BMI, osteoporosis, baseline pelvic incidence, and T1 pelvic angle, was used to evaluate the complication rates and radiographic and patient-reported outcomes between the groups., Results: A total of 93 patients were included, 53% of whom underwent MLG and 47% of whom underwent 3CO. The MLG group had a lower BMI (p < 0.05). MLG patients received fewer previous fusions than 3CO patients (31% vs 80%, p < 0.001). MLG patients had 24% less blood loss but a 22% longer operative time (565 vs 419 minutes, p = 0.008). Using adjusted analysis, the 3CO group had greater segmental and relative correction at each level (segmental utility ratio mean 69% for 3CO vs 23% for MLG, p < 0.001). However, the 3CO group had lordotic differences between two adjacent lumbar disc pairs (range -0.5° to 9.0°, p = 0.009), while MLG was more harmonious (range 2.2°-6.5°, p > 0.4). MLG patients were more likely to undergo realignment to age-adjusted standards (OR 5.6, 95% CI 1.2-46.4; p = 0.033). MLG patients were less likely to develop neurological complications or undergo reoperation (OR 0.4, 95% CI 0.1-0.9; p = 0.041). Adjusted analysis revealed that MLG patients more often met a substantial clinical benefit in the Oswestry Disability Index score (OR 5.3, 95% CI 1.1-26.8; p = 0.043)., Conclusions: MLG techniques showed better utility in lumbar distribution and age-adjusted global correction while minimizing neurological complications and reoperation rates by 2 years postoperatively. In selected instances, these techniques may offer the spine deformity surgeon a safer alternative when correcting severe adult spinal deformity.

Objective: Sagittal alignment measured on standing radiography remains a fundamental component of surgical planning for adult spinal deformity (ASD). However, the relationship between classic sagittal alignment parameters and objective metrics, such as walking time (WT) and grip strength (GS), remains unknown. The objective of this work was to determine if ASD patients with worse baseline sagittal malalignment have worse objective physical metrics and if those metrics have a stronger relationship to patient-reported outcome metrics (PROMs) than standing alignment., Methods: The authors conducted a retrospective review of a multicenter ASD cohort. ASD patients underwent baseline testing with the timed up-and-go 6-m walk test (seconds) and for GS (pounds). Baseline PROMs were surveyed, including Oswestry Disability Index (ODI), Patient-Reported Outcomes Measurement Information System (PROMIS), Scoliosis Research Society (SRS)-22r, and Veterans RAND 12 (VR-12) scores. Standard spinopelvic measurements were obtained (sagittal vertical axis [SVA], pelvic tilt [PT], and mismatch between pelvic incidence and lumbar lordosis [PI-LL], and SRS-Schwab ASD classification). Univariate and multivariable linear regression modeling was performed to interrogate associations between objective physical metrics, sagittal parameters, and PROMs., Results: In total, 494 patients were included, with mean ± SD age 61 ± 14 years, and 68% were female. Average WT was 11.2 ± 6.1 seconds and average GS was 56.6 ± 24.9 lbs. With increasing PT, PI-LL, and SVA quartiles, WT significantly increased (p < 0.05). SRS-Schwab type N patients demonstrated a significantly longer average WT (12.5 ± 6.2 seconds), and type T patients had a significantly shorter WT time (7.9 ± 2.7 seconds, p = 0.03). With increasing PT quartiles, GS significantly decreased (p < 0.05). SRS-Schwab type T patients had a significantly higher average GS (68.8 ± 27.8 lbs), and type L patients had a significantly lower average GS (51.6 ± 20.4 lbs, p = 0.03). In the frailty-adjusted multivariable linear regression analyses, WT was more strongly associated with PROMs than sagittal parameters. GS was more strongly associated with ODI and PROMIS Physical Function scores., Conclusions: The authors observed that increasing baseline sagittal malalignment is associated with slower WT, and possibly weaker GS, in ASD patients. WT has a stronger relationship to PROMs than standing alignment parameters. Objective physical metrics likely offer added value to standard spinopelvic measurements in ASD evaluation and surgical planning.

Objective: Complex spinal deformity surgeries may involve significant blood loss. The use of antifibrinolytic agents such as tranexamic acid (TXA) has been proven to reduce perioperative blood loss. However, for patients with a history of thromboembolic events, there is concern of increased risk when TXA is used during these surgeries. This study aimed to assess whether TXA use in patients undergoing complex spinal deformity correction surgeries increases the risk of thromboembolic complications based on preexisting thromboembolic risk factors., Methods: Data were analyzed for adult patients who received TXA during surgical correction for spinal deformity at 21 North American centers between August 2018 and October 2022. Patients with preexisting thromboembolic events and other risk factors (history of deep venous thrombosis [DVT], pulmonary embolism [PE], myocardial infarction [MI], stroke, peripheral vascular disease, or cancer) were identified. Thromboembolic complication rates were assessed during the postoperative 90 days. Univariate and multivariate analyses were performed to assess thromboembolic outcomes in high-risk and low-risk patients who received intravenous TXA., Results: Among 411 consecutive patients who underwent complex spinal deformity surgery and received TXA intraoperatively, 130 (31.6%) were considered high-risk patients. There was no significant difference in thromboembolic complications between patients with and those without preexisting thromboembolic risk factors in univariate analysis (high-risk group vs low-risk group: 8.5% vs 2.8%, p = 0.45). Specifically, there were no significant differences between groups regarding the 90-day postoperative rates of DVT (high-risk group vs low-risk group: 1.5% vs 1.4%, p = 0.98), PE (2.3% vs 1.8%, p = 0.71), acute MI (1.5% vs 0%, p = 0.19), or stroke (0.8% vs 1.1%, p > 0.99). On multivariate analysis, high-risk status was not a significant independent predictor for any of the thromboembolic complications., Conclusions: Administration of intravenous TXA during the correction procedure did not change rates of thromboembolic events, acute MI, or stroke in this cohort of adult spinal deformity surgery patients.

Objective: The present study utilized recently developed in-construct measurements in simulations of cervical deformity surgery in order to assess undercorrection and predict distal junctional kyphosis (DJK)., Methods: A retrospective review of a database of operative cervical deformity patients was analyzed for severe DJK and mild DJK. C2-lower instrumented vertebra (LIV) sagittal angle (SA) was measured postoperatively, and the correction was simulated in the preoperative radiograph in order to match the C2-LIV by using the planning software. Linear regression analysis that used C2 pelvic angle (CPA) and pelvic tilt (PT) determined the simulated PT that matched the virtual CPA. Linear regression analysis was used to determine the C2-T1 SA, C2-T4 SA, and C2-T10 SA that corresponded to DJK of 20° and cervical sagittal vertical axis (cSVA) of 40 mm., Results: Sixty-nine cervical deformity patients were included. Severe and mild DJK occurred in 11 (16%) and 22 (32%) patients, respectively; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and mild DJK patients had worse alignment compared to non-DJK patients in terms of cSVA (42.5 mm vs 33.0 mm vs 23.4 mm, p < 0.001) and C2-LIV SVA (68.9 mm vs 57.3 mm vs 36.8 mm, p < 0.001). Linear regression revealed the relationships between in-construct measures (C2-T1 SA, C2-T4 SA, and C2-T10 SA), cSVA, and change in DJK (all R > 0.57, p < 0.001). A cSVA of 40 mm corresponded to C2-T4 SA of 10.4° and C2-T10 SA of 28.0°. A DJK angle change of 10° corresponded to C2-T4 SA of 5.8° and C2-T10 SA of 20.1°., Conclusions: Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of cervical deformity correction.

Objective: Depression has been implicated with worse immediate postoperative outcomes in adult spinal deformity (ASD) correction, yet the specific impact of depression on those patients undergoing minimally invasive surgery (MIS) requires further clarity. This study aimed to evaluate the role of depression in the recovery of patients with ASD after undergoing MIS., Methods: Patients who underwent MIS for ASD with a minimum postoperative follow-up of 1 year were included from a prospectively collected, multicenter registry. Two cohorts of patients were identified that consisted of either those affirming or denying depression on preoperative assessment. The patient-reported outcome measures (PROMs) compared included scores on the Oswestry Disability Index (ODI), numeric rating scale (NRS) for back and leg pain, Scoliosis Research Society Outcomes Questionnaire (SRS-22), SF-36 physical component summary, SF-36 mental component summary (MCS), EQ-5D, and EQ-5D visual analog scale., Results: Twenty-seven of 147 (18.4%) patients screened positive for preoperative depression. The nondepressed cohort had an average of 4.83 levels fused, and the depressed cohort had 5.56 levels fused per patient (p = 0.267). At 1-year follow-up, 10 patients still reported depression, representing a 63% decrease. Postoperatively, both cohorts demonstrated improvement in their PROMs; however, at 1-year follow-up, those without depression had statistically better outcomes based on the EQ-5D, MCS, and SRS-22 scores (p < 0.05). Patients with depression continued to experience higher NRS leg scores at 1-year follow-up (3.63 vs 2.22, p = 0.018). After controlling for covariates, the authors found that depression significantly impacted only 1-year follow-up MCS scores (β = 8.490, p < 0.05)., Conclusions: Depressed and nondepressed patients reported similar improvements after MIS surgery, except MCS scores were more likely to improve in nondepressed patients.

Objective: The objective was to determine the degree of regional decompensation to pelvic tilt (PT) normalization after complex adult spinal deformity (ASD) surgery., Methods: Operative ASD patients with 1 year of PT measurements were included. Patients with normalized PT at baseline were excluded. Predicted PT was compared to actual PT, tested for change from baseline, and then compared against age-adjusted, Scoliosis Research Society-Schwab, and global alignment and proportion (GAP) scores. Lower-extremity (LE) parameters included the cranial-hip-sacrum angle, cranial-knee-sacrum angle, and cranial-ankle-sacrum angle. LE compensation was set as the 1-year upper tertile compared with intraoperative baseline. Univariate analyses were used to compare normalized and nonnormalized data against alignment outcomes. Multivariable logistic regression analyses were used to develop a model consisting of significant predictors for normalization related to regional compensation., Results: In total, 156 patients met the inclusion criteria (mean ± SD age 64.6 ± 9.1 years, BMI 27.9 ± 5.6 kg/m2, Charlson Comorbidity Index 1.9 ± 1.6). Patients with normalized PT were more likely to have overcorrected pelvic incidence minus lumbar lordosis and sagittal vertical axis at 6 weeks (p < 0.05). GAP score at 6 weeks was greater for patients with nonnormalized PT (0.6 vs 1.3, p = 0.08). At baseline, 58.5% of patients had compensation in the thoracic and cervical regions. Postoperatively, compensation was maintained by 42% with no change after matching in age-adjusted or GAP score. The patients with nonnormalized PT had increased rates of thoracic and cervical compensation (p < 0.05). Compensation in thoracic kyphosis differed between patients with normalized PT at 6 weeks and those with normalized PT at 1 year (69% vs 35%, p < 0.05). Those who compensated had increased rates of implant complications by 1 year (OR [95% CI] 2.08 [1.32-6.56], p < 0.05). Cervical compensation was maintained at 6 weeks and 1 year (56% vs 43%, p = 0.12), with no difference in implant complications (OR 1.31 [95% CI -2.34 to 1.03], p = 0.09). For the lower extremities at baseline, 61% were compensating. Matching age-adjusted alignment did not eliminate compensation at any joint (all p > 0.05). Patients with nonnormalized PT had higher rates of LE compensation across joints (all p < 0.01). Overall, patients with normalized PT at 1 year had the greatest odds of resolving LE compensation (OR 9.6, p < 0.001). Patients with normalized PT at 1 year had lower rates of implant failure (8.9% vs 19.5%, p < 0.05), rod breakage (1.3% vs 13.8%, p < 0.05), and pseudarthrosis (0% vs 4.6%, p < 0.05) compared with patients with nonnormalized PT. The complication rate was significantly lower for patients with normalized PT at 1 year (56.7% vs 66.1%, p = 0.02), despite comparable health-related quality of life scores., Conclusions: Patients with PT normalization had greater rates of resolution in thoracic and LE compensation, leading to lower rates of complications by 1 year. Thus, consideration of both the lower extremities and thoracic regions in surgical planning is vital to preventing adverse outcomes and maintaining pelvic alignment.

Cervical spine deformity surgery has significantly evolved over recent decades. There has been substantial work performed, which has furthered the true understanding of alignment and advancements in surgical technique and instrumentation. Concomitantly, understanding of cervical spine pathology and the contributing drivers have also improved, which have influenced the development of classification systems for cervical spine deformity and the development of treatment-guiding algorithms. This article aims to provide a synopsis of the current knowledge surrounding cervical spine deformity to date, with particular focus on preoperative expected alignment targets, perioperative optimization, and the whole operative strategy.

Objective: The purpose of this study was to investigate the cost utility of nonoperative treatment for adult spinal deformity (ASD)., Methods: Nonoperatively and operatively treated patients who met database criteria for ASD and in whom complete radiographic and health-related quality of life data at baseline and at 2 years were available were included. A cost analysis was completed on the PearlDiver database assessing the average cost of nonoperative treatment prior to surgical intervention based on previously published treatments (NSAIDs, narcotics, muscle relaxants, epidural steroid injections, physical therapy, and chiropractor). Utility data were calculated using the Oswestry Disability Index (ODI) converted to SF-6D with published conversion methods. Quality-adjusted life years (QALYs) used a 3% discount rate to account for residual decline in life expectancy (78.7 years). Minor and major comorbidities and complications were assessed according to the CMS.gov manual's definitions. Successful nonoperative treatment was defined as a gain in the minimum clinically importance difference (MCID) in both ODI and Scoliosis Research Society (SRS)-pain scores, and failure was defined as a loss in MCID or conversion to operative treatment. Patients with baseline ODI ≤ 20 and continued ODI of ≤ 20 at 2 years were considered nonoperative successful maintenance. The average utilization of nonoperative treatment and cost were applied to the ASD cohort., Results: A total of 824 patients were included (mean age 58.24 years, 81% female, mean body mass index 27.2 kg/m2). Overall, 75.5% of patients were in the operative and 24.5% were in the nonoperative cohort. At baseline patients in the operative cohort were significantly older, had a greater body mass index, increased pelvic tilt, and increased pelvic incidence-lumbar lordosis mismatch (all p < 0.05). With respect to deformity, patients in the operative group had higher rates of severe (i.e., ++) sagittal deformity according to SRS-Schwab modifiers for pelvic tilt, sagittal vertical axis, and pelvic incidence-lumbar lordosis mismatch (p < 0.05). At 2 years, patients in the operative cohort showed significantly increased rates of a gain in MCID for physical component summary of SF-36, ODI, and SRS-activity, SRS-pain, SRS-appearance, and SRS-mental scores. Cost analysis showed the average cost of nonoperative treatment 2 years prior to surgical intervention to be $2041. Overall, at 2 years patients in the nonoperative cohort had again in ODI of 0.36, did not show a gain in QALYs, and nonoperative treatment was determined to be cost-ineffective. However, a subset of patients in this cohort underwent successful maintenance treatment and had a decrease in ODI of 1.1 and a gain in utility of 0.006 at 2 years. If utility gained for this cohort was sustained to full life expectancy, patients' cost per QALY was $18,934 compared to a cost per QALY gained of $70,690.79 for posterior-only and $48,273.49 for combined approach in patients in the operative cohort., Conclusions: Patients with ASD undergoing operative treatment at baseline had greater sagittal deformity and greater improvement in health-related quality of life postoperatively compared to patients treated nonoperatively. Additionally, patients in the nonoperative cohort overall had an increase in ODI and did not show improvement in utility gained. Patients in the nonoperative cohort who had low disability and sagittal deformity underwent successful maintenance and cost-effective treatment.

Objective: The objective of this study was to assess whether delaying surgical management of cervical deformity (CD) in patients with concomitant mild myelopathy increases the risk of suboptimal outcomes., Methods: Patients aged ≥ 18 years who had a baseline diagnosis of mild myelopathy with baseline and up to 2 years of postoperative data were assessed. Patients were categorized as having CD (CD+) or not (CD-) at baseline. Patients with symptoms of myelopathy for more than 1 year after the initial visit prior to surgery were considered delayed. Clinical and radiographic data were assessed using means comparison analyses. Multivariate regression analysis assessed correlations between increasing time to surgery and peri- and postoperative outcomes adjusted for baseline age and frailty score. Backstep logistic regression analysis assessed the risk of complications or reoperation, while controlling for baseline T1 slope minus cervical lordosis (TS-CL)., Results: One hundred six patients were included (mean age 58.11 ± 11.97 years, 48% female, mean BMI 29.13 ± 6.89). Of the patients with baseline mild myelopathy, 22 (20.8%) were CD- while 84 (79.2%) were CD+. Overall, 9.5% of patients were considered to have delayed surgery. Linear regression revealed that both CD- and CD+ patients were more likely to require reoperation when there was more time between the initial visit and surgical admission (p < 0.001). Additionally, an adjusted logistic regression indicated that CD+ patients who had a greater length of time to surgery had a higher likelihood for major complications (p < 0.001). Conversely, CD+ patients who were operated on within 30 days of the initial visit had a significantly lower risk for a major complication (OR 0.901, 95% CI 0.889-1.105, p = 0.043), and a lower risk for reoperation (OR 0.954, 95% CI 0.877-1.090, p = 0.043), while controlling for the severity of deformity based on baseline TS-CL., Conclusions: The findings of this study demonstrate that a delay in surgery after the initial visit significantly increases the risk for major complications and reoperation in patients with CD with associated mild baseline myelopathy. Early operative treatment in this patient population may lower the risk of postoperative complications.

Objective: The objective of this study was to adjust the sagittal age-adjusted score (SAAS) to accommodate frailty in alignment considerations and thereby increase the predictability of clinical outcomes and junctional failure., Methods: Surgical adult spinal deformity (ASD) patients with 2-year data were included. Frailty was assessed with the continuous ASD modified frailty index (ASD-mFI). Two-year outcomes were proximal junctional kyphosis (PJK), proximal junctional failure (PJF), major mechanical complications, and best clinical outcome (BCO), defined as Oswestry Disability Index (ODI) score < 15 and Scoliosis Research Society outcomes questionnaire total score > 4.5 by 2 years. Linear regression analysis established a 6-week score based on the component scores of SAAS, frailty, and US normal values for ODI score. Logistic regression analysis followed by conditional inference tree run forest analysis generated categorical thresholds. Multivariate analysis, controlling for age, baseline deformity, and history of revision, was used to compare outcome rates, and logistic regression generated odds ratios for the continuous score. Thirty percent of the cohort was used as a random sample for internal validation., Results: In total, 412 patients were included (mean ± SD age 60.1 ± 14.2 years, 80% female, BMI 26.9 ± 5.4 kg/m2). Baseline frailty categories were as follows: 57% not frail, 30% frail, and 14% severely frail. Overall, by 2 years, 39% of patients had developed PJK, 8% PJF, and 21% mechanical complications; 22% had undergone a reoperation; and 15% met BCO. When the cohort as a whole was assessed, the 6-week SAAS had a correlation with the development of PJK and PJF, but not mechanical complications, reoperation, or BCO. Development of mechanical complications, PJF, reoperation, and BCO demonstrated correlations with ASD-mFI (all p < 0.05). Regression analysis modifying SAAS on the basis of ODI norms and frailty generated the following equation: frailty-adjusted SAAS (FAS) = 0.108 × T1 pelvic angle + 0.162 × pelvic tilt - 0.39 × pelvic incidence - lumbar lordosis - 0.03 × ASD-mFI - 1.6771. With conditional inference tree analysis, thresholds were derived for FAS: aligned < 1.7, offset 1.7-2.2, and severely offset > 2.2. Significance between FAS categories was found for PJK, PJF, mechanical complications, reoperation, and BCO by 2 years. Binary logistic regression, controlling for baseline deformity and revision status, demonstrated significance between FAS and all 5 outcome variables (all p < 0.01). Internal validation saw each outcome variable maintain significance between categories, with even greater odds for PJF (OR 13.4, 95% CI 4.7-38.3, p < 0.001)., Conclusions: Consideration of physiological age, in addition to chronological age, may be beneficial in the management of operative goals to maximize clinical outcomes while minimizing junctional failure. This combination enables the spine surgeon to fortify a surgical plan for even the most challenging patients undergoing ASD corrective surgery.

Objective: The authors of this study sought to evaluate the predictive role of global sagittal alignment and upper instrumented vertebra (UIV) level in symptomatic proximal junctional kyphosis (PJK) among patients with adult spinal deformity (ASD)., Methods: Data on ASD patients who had undergone fusion of ≥ 5 vertebrae from 2008 to 2018 and with a minimum follow-up of 1 year were obtained from a prospectively collected multicenter database and evaluated (n = 1312). Radiographs were obtained preoperatively and at 6 weeks, 6 months, 1 year, 2 years, and 3 years postoperatively. The 22-Item Scoliosis Research Society Patient Questionnaire Revised (SRS-22r) scores were collected preoperatively, 1 year postoperatively, and 2 years postoperatively. Symptomatic PJK was defined as a kyphotic increase > 20° in the Cobb angle from the UIV to the UIV+2. At 6 weeks postoperatively, sagittal parameters were evaluated and patients were categorized by global alignment and proportion (GAP) score/category and SRS-Schwab sagittal modifiers. Patients were stratified by UIV level: upper thoracic (UT) UIV ≥ T8 or lower thoracic (LT) UIV ≤ T9., Results: Patients who developed symptomatic PJK (n = 260) had worse 1-year postoperative SRS-22r mental health (3.70 vs 3.86) and total (3.56 vs 3.67) scores, as well as worse 2-year postoperative self-image (3.45 vs 3.65) and satisfaction (4.03 vs 4.22) scores (all p ≤ 0.04). In the whole study cohort, patients with PJK had less pelvic incidence-lumbar lordosis (PI-LL) mismatch (-0.24° vs 3.29°, p < 0.001) but no difference in their GAP score/category or SRS-Schwab sagittal modifiers compared with the patients without PJK. Regression showed a higher risk of PJK with a pelvic tilt (PT) grade ++ (OR 2.35) and less risk with a PI-LL grade ++ (OR 0.35; both p < 0.01). When specifically analyzing the LT UIV cohort, patients with PJK had a higher GAP score (5.66 vs 4.79), greater PT (23.02° vs 20.90°), and less PI-LL mismatch (1.61° vs 4.45°; all p ≤ 0.02). PJK patients were less likely to be proportioned postoperatively (17.6% vs 30.0%, p = 0.015), and regression demonstrated a greater PJK risk with severe disproportion (OR 1.98) and a PT grade ++ (OR 3.15) but less risk with a PI-LL grade ++ (OR 0.45; all p ≤ 0.01). When specifically evaluating the UT UIV cohort, the PJK patients had less PI-LL mismatch (-2.11° vs 1.45°) but no difference in their GAP score/category. Regression showed a greater PJK risk with a PT grade + (OR 1.58) and a decreased risk with a PI-LL grade ++ (OR 0.21; both p < 0.05)., Conclusions: Symptomatic PJK leads to worse patient-reported outcomes and is associated with less postoperative PI-LL mismatch and greater postoperative PT. A worse postoperative GAP score and disproportion are only predictive of symptomatic PJK in patients with an LT UIV.

Objective: The aim of this study was to investigate whether surgery for high-risk patients is being optimized over time and if poor outcomes are being minimized., Methods: Patients who underwent surgery for cervical deformity (CD) and were ≥ 18 years with baseline and 2-year data were stratified by year of surgery from 2013 to 2018. The cohort was divided into two groups based on when the surgery was performed. Patients in the early cohort underwent surgery between 2013 and 2015 and those in the recent cohort underwent surgery between 2016 and 2018. High-risk patients met at least 2 of the following criteria: 1) baseline C2-7 Cobb angle > 15°, mismatch between T1 slope and cervical lordosis ≥ 35°, C2-7 sagittal vertical axis > 4 cm, or chin-brow vertical angle > 25°; 2) age ≥ 70 years; 3) severe baseline frailty (Miller index); 4) Charlson Comorbidity Index (CCI) ≥ 1 SD above the mean; 5) three-column osteotomy as treatment; and 6) fusion > 10 levels or > 7 levels for elderly patients. The mean comparison analysis assessed differences between groups. Stepwise multivariable linear regression described associations between increasing year of surgery and complications., Results: Eighty-two CD patients met high-risk criteria (mean age 62.11 ± 10.87 years, 63.7% female, mean BMI 29.70 ± 8.16 kg/m2, and mean CCI 1.07 ± 1.45). The proportion of high-risk patients increased with time, with 41.8% of patients in the early cohort classified as high risk compared with 47.6% of patients in the recent cohort (p > 0.05). Recent high-risk patients were more likely to be female (p = 0.008), have a lower BMI (p = 0.038), and have a higher baseline CCI (p = 0.013). Surgically, high-risk patients in the recent cohort were more likely to undergo low-grade osteotomy (p = 0.003). By postoperative complications, recent high-risk patients were less likely to experience any postoperative adverse events overall (p = 0.020) or complications such as dysphagia (p = 0.045) at 2 years. Regression analysis revealed increasing year of surgery to be correlated with decreasing minor complication rates (p = 0.030), as well as lowered rates of distal junctional kyphosis by 2 years (p = 0.048)., Conclusions: Over time, high-risk CD patients have an increase in frequency and comorbidity rates but have demonstrated improved postoperative outcomes. These findings suggest that spine surgeons have improved over time in optimizing selection and reducing potential adverse events in high-risk patients.

Objective: The objective of this study was to identify the effect of baseline cervical deformity (CD) on proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in patients with adult spinal deformity (ASD)., Methods: This study was a retrospective analysis of a prospectively collected, multicenter database comprising ASD patients enrolled at 13 participating centers from 2009 to 2018. Included were ASD patients aged > 18 years with concurrent CD (C2-7 kyphosis < -15°, T1S minus cervical lordosis > 35°, C2-7 sagittal vertical axis > 4 cm, chin-brow vertical angle > 25°, McGregor's slope > 20°, or C2-T1 kyphosis > 15° across any three vertebrae) who underwent surgery. Patients were grouped according to four deformity classification schemes: Ames and Passias CD modifiers, sagittal morphotypes as described by Kim et al., and the head versus trunk balance system proposed by Mizutani et al. Mean comparison tests and multivariable binary logistic regression analyses were performed to assess the impact of these deformity classifications on PJK and PJF rates up to 3 years following surgery., Results: A total of 712 patients with concurrent ASD and CD met the inclusion criteria (mean age 61.7 years, 71% female, mean BMI 28.2 kg/m2, and mean Charlson Comorbidity Index 1.90) and underwent surgery (mean number of levels fused 10.1, mean estimated blood loss 1542 mL, and mean operative time 365 minutes; 70% underwent osteotomy). By approach, 59% of the patients underwent a posterior-only approach and 41% underwent a combined approach. Overall, 277 patients (39.1%) had PJK by 1 year postoperatively, and an additional 189 patients (26.7%) developed PJK by 3 years postoperatively. Overall, 65 patients (9.2%) had PJF by 3 years postoperatively. Patients classified as having a cervicothoracic deformity morphotype had higher rates of early PJK than flat neck deformity and cervicothoracic deformity patients (p = 0.020). Compared with the head-balanced patients, trunk-balanced patients had higher rates of PJK and PJF (both p < 0.05). Examining Ames modifier severity showed that patients with moderate and severe deformity by the horizontal gaze modifier had higher rates of PJK (p < 0.001)., Conclusions: In patients with concurrent cervical and thoracolumbar deformities undergoing isolated thoracolumbar correction, the use of CD classifications allows for preoperative assessment of the potential for PJK and PJF that may aid in determining the correction of extending fusion levels.

Objective: Multiple rods are utilized in adult spinal deformity (ASD) surgery to increase construct stiffness. However, the impact of multiple rods on proximal junctional kyphosis (PJK) is not well established. This study aimed to investigate the impact of multiple rods on PJK incidence in ASD patients., Methods: ASD patients from a prospective multicenter database with a minimum follow-up of 1 year were retrospectively reviewed. Clinical and radiographic data were collected preoperatively, at 6 weeks postoperatively, at 6 months postoperatively, at 1 year postoperatively, and at every subsequent year postoperatively. PJK was defined as a kyphotic increase of > 10° in the Cobb angle from the upper instrumented vertebra (UIV) to UIV+2 as compared with preoperative values. Demographic data, radiographic parameters, and PJK incidence were compared between the multirod and dual-rod patient cohorts. PJK-free survival analysis was performed using Cox regression to control for demographic characteristics, comorbidities, level of fusion, and radiographic parameters., Results: Overall, 307/1300 (23.62%) cases utilized multiple rods. Cases with multiple rods were more likely to be revisions (68.4% vs 46.5%, p < 0.001), to be posterior only (80.7% vs 61.5%, p < 0.001), involve more levels of fusion (mean 11.73 vs 10.60, p < 0.001), and include 3-column osteotomy (42.9% vs 17.1%, p < 0.001). Patients with multiple rods also had greater preoperative pelvic retroversion (mean pelvic tilt 27.95° vs 23.58°, p < 0.001), greater thoracolumbar junction kyphosis (-15.9° vs -11.9°, p = 0.001), and more severe sagittal malalignment (C7-S1 sagittal vertical axis 99.76 mm vs 62.23 mm, p < 0.001), all of which corrected postoperatively. Patients with multiple rods had similar incidence rates of PJK (58.6% vs 58.1%) and revision surgery (13.0% vs 17.7%). The PJK-free survival analysis demonstrated equivalent PJK-free survival durations among the patients with multiple rods (HR 0.889, 95% CI 0.745-1.062, p = 0.195) after controlling for demographic and radiographic parameters. Further stratification based on implant metal type demonstrated noninferior PJK incidence rates with multiple rods in the titanium (57.1% vs 54.6%, p = 0.858), cobalt chrome (60.5% vs 58.7%, p = 0.646), and stainless steel (20% vs 63.7%, p = 0.008) cohorts., Conclusions: Multirod constructs for ASD are most frequently utilized in revision, long-level reconstructions with 3-column osteotomy. The use of multiple rods in ASD surgery does not result in an increased incidence of PJK and is not affected by rod metal type.

Objective: The objective of this study was to calibrate an updated predictive model incorporating novel clinical, radiographic, and prophylactic measures to assess the risk of proximal junctional kyphosis (PJK) and failure (PJF)., Methods: Operative patients with adult spinal deformity (ASD) and baseline and 2-year postoperative data were included. PJK was defined as ≥ 10° in sagittal Cobb angle between the inferior uppermost instrumented vertebra (UIV) endplate and superior endplate of the UIV + 2 vertebrae. PJF was radiographically defined as a proximal junctional sagittal Cobb angle ≥ 15° with the presence of structural failure and/or mechanical instability, or PJK with reoperation. Backstep conditional binary supervised learning models assessed baseline demographic, clinical, and surgical information to predict the occurrence of PJK and PJF. Internal cross validation of the model was performed via a 70%/30% cohort split. Conditional inference tree analysis determined thresholds at an alpha level of 0.05., Results: Seven hundred seventy-nine patients with ASD (mean 59.87 ± 14.24 years, 78% female, mean BMI 27.78 ± 6.02 kg/m2, mean Charlson Comorbidity Index 1.74 ± 1.71) were included. PJK developed in 50.2% of patients, and 10.5% developed PJF by their last recorded visit. The six most significant demographic, radiographic, surgical, and postoperative predictors of PJK/PJF were baseline age ≥ 74 years, baseline sagittal age-adjusted score (SAAS) T1 pelvic angle modifier > 1, baseline SAAS pelvic tilt modifier > 0, levels fused > 10, nonuse of prophylaxis measures, and 6-week SAAS pelvic incidence minus lumbar lordosis modifier > 1 (all p < 0.015). Overall, the model was deemed significant (p < 0.001), and internally validated receiver operating characteristic analysis returned an area under the curve of 0.923, indicating robust model fit., Conclusions: PJK and PJF remain critical concerns in ASD surgery, and efforts to reduce the occurrence of PJK and PJF have resulted in the development of novel prophylactic techniques and enhanced clinical and radiographic selection criteria. This study demonstrates a validated model incorporating such techniques that may allow for the prediction of clinically significant PJK and PJF, and thus assist in optimizing patient selection, enhancing intraoperative decision making, and reducing postoperative complications in ASD surgery.

Objective: The purpose of this study was to discern factors that differentiate patients who experience postoperative lower-extremity motor function decline in the early postoperative period., Methods: Adult spinal deformity (ASD) patients who were enrolled in a multicenter, observational, and prospectively collected study from 2018 to 2021 at 18 spinal deformity centers in North America were queried. Eligible participants met at least one of the following radiographic and/or procedural inclusion criteria: pelvic incidence minus lumbar lordosis (PI-LL) ≥ 25°, T1 pelvic angle (T1PA) ≥ 30°, sagittal vertical axis (SVA) ≥ 15 cm, thoracic scoliosis ≥ 70°, thoracolumbar scoliosis ≥ 50°, global coronal malalignment ≥ 7 cm, 3-column osteotomy, spinal fusion ≥ 12 levels, and/or age ≥ 65 years with ≥ 7 levels of instrumentation. Patients with an inflammatory or autoimmune disease and those who were incarcerated or pregnant were excluded, as were non-English speakers. Only patients with baseline and 6-week postoperative lower-extremity motor score (LEMS) were analyzed. Patient information, including demographic data, operative data, patient-reported outcomes, and radiographic parameters, were collected. Univariate and multivariable logistic regression models were built to quantify the degree to which a patient's postoperative LEMS decline was related to demographic and clinical characteristics., Results: In total, 205 patients (mean age 61.5 years, mean total instrumented levels 12.6, 67.3% female, 54.2% primary cases, 79.5% with pelvic fixation) were evaluated. Of these 205 patients, 32 (15.5%) experienced LEMS decline in the perioperative period. These patients were older (p = 0.0014) and had greater BMI (p = 0.0176), higher frailty scores (p = 0.047), longer operating room times (p = 0.033), and greater estimated blood loss (p < 0.0001), and they were more frequently observed to have intraoperative neurophysiological monitoring (IONM) changes (p = 0.018). The deteriorated cohort had greater C7SVA at baseline (p = 0.0028) but were comparable in terms of all other radiographic parameters. No radiographic differences were seen between the groups at the 6-week visit; however, the deteriorated cohort experienced greater change in PI-LL (p < 0.0001), lumbar lordosis (p = 0.0461), C7SVA (p = 0.0004), and T1PA (p < 0.0001). Multivariate logistic regression demonstrated that the presence of IONM changes and each degree of negative change in T1PA conferred 3.71 (95% CI 1.01-13.42) and 1.09 (1.01-1.19) greater odds of postoperative LEMS deterioration, respectively., Conclusions: In this study, 15.6% of ASD patients incurred LEMS decline in the perioperative period. The magnitude of change in global sagittal alignment, specifically T1PA, was the strongest independent predictor of LEMS decline, which has implications for surgical planning, patient counseling, and clinical research.

Objective: Circumferential minimally invasive surgery (cMIS) may provide incremental benefits compared with open surgery for patients with increasing frailty status by decreasing peri- and postoperative complications., Methods: Operative patients with adult spinal deformity (ASD) ≥ 18 years old with baseline and 2-year postoperative data were assessed. With propensity score matching, patients who underwent cMIS (cMIS group) were matched with similar patients who underwent open surgery (open group) based on baseline BMI, C7-S1 sagittal vertical axis, pelvic incidence to lumbar lordosis mismatch, and S1 pelvic tilt. The Passias modified ASD frailty index (mASD-FI) was used to determine patient frailty stratification as not frail, frail, or severely frail. Baseline and postoperative factors were assessed using two-way analysis of covariance (ANCOVA) and multivariate ANCOVA while controlling for baseline age, Charlson Comorbidity Index (CCI) score, and number of levels fused., Results: After propensity score matching, 170 ASD patients (mean age 62.71 ± 13.64 years, 75.0% female, mean BMI 29.25 ± 6.60 kg/m2) were included, split evenly between the cMIS and open groups. Surgically, patients in the open group had higher numbers of posterior levels fused (p = 0.021) and were more likely to undergo three-column osteotomies (p > 0.05). Perioperatively, cMIS patients had lower intraoperative blood loss and decreased use of cell saver across frailty groups (with adjustment for baseline age, CCI score, and levels fused), as well as fewer perioperative complications (p < 0.001). Adjusted analysis also revealed that compared to open patients, increasingly frail patients in the cMIS group were also more likely to demonstrate greater improvement in 1- and 2-year postoperative scores for the Oswestry Disability Index, SRS-36 (total), EQ-5D and SF-36 (all p < 0.05). With regard to postoperative complications, increasingly frail patients in the cMIS group were also noted to experience significantly fewer complications overall (p = 0.036) and fewer major intraoperative complications (p = 0.039). The cMIS patients were also less likely to need a reoperation than their open group counterparts (p = 0.043)., Conclusions: Surgery performed with a cMIS technique may offer acceptable outcomes, with diminishment of perioperative complications and mitigation of catastrophic outcomes, in increasingly frail patients who may not be candidates for surgery using traditional open techniques. However, further studies should be performed to investigate the long-term impact of less optimal alignment in this population.

Objective: Management of adult spinal deformity (ASD) has increasingly favored operative intervention; however, the incidence of complications and reoperations is high, and patients may fail to achieve idealized postsurgical results. This study compared health-related quality of life (HRQOL) metrics between patients with suboptimal surgical outcomes and those who underwent nonoperative management as a proxy for the natural history (NH) of ASD., Methods: ASD patients with 2-year data were included. Patients who were offered surgery but declined were considered nonoperative (i.e., NH) patients. Operative patients with suboptimal outcome (SOp)-defined as any reoperation, major complication, or ≥ 2 severe Scoliosis Research Society (SRS)-Schwab modifiers at follow-up-were selected for comparison. Propensity score matching (PSM) on the basis of baseline age, deformity, SRS-22 Total, and Charlson Comorbidity Index score was used to match the groups. ANCOVA and stepwise logistic regression analysis were used to assess outcomes between groups at 2 years., Results: In total, 441 patients were included (267 SOp and 174 NH patients). After PSM, 142 patients remained (71 SOp 71 and 71 NH patients). At baseline, the SOp and NH groups had similar demographic characteristics, HRQOL, and deformity (all p > 0.05). At 2 years, ANCOVA determined that NH patients had worse deformity as measured with sagittal vertical axis (36.7 mm vs 21.3 mm, p = 0.025), mismatch between pelvic incidence and lumbar lordosis (11.9° vs 2.9°, p < 0.001), and pelvic tilt (PT) (23.1° vs 20.7°, p = 0.019). The adjusted regression analysis found that SOp patients had higher odds of reaching the minimal clinically important differences in Oswestry Disability Index score (OR [95% CI] 4.5 [1.7-11.5], p = 0.002), SRS-22 Activity (OR [95% CI] 3.2 [1.5-6.8], p = 0.002), SRS-22 Pain (OR [95% CI] 2.8 [1.4-5.9], p = 0.005), and SRS-22 Total (OR [95% CI] 11.0 [3.5-34.4], p < 0.001)., Conclusions: Operative patients with SOp still experience greater improvements in deformity and HRQOL relative to the progressive radiographic and functional deterioration associated with the NH of ASD. The NH of nonoperative management should be accounted for when weighing the risks and benefits of operative intervention for ASD.

Objective: The objective of this study was to evaluate spinopelvic sagittal alignment and spinal compensatory changes in adult cervical kyphotic deformity., Methods: A database composed of 13 US spine centers was retrospectively reviewed for adult patients who underwent cervical reconstruction with radiographic evidence of cervical kyphotic deformity: C2-7 sagittal vertical axis > 4 cm, chin-brow vertical angle > 25°, or cervical kyphosis (T1 slope [T1S] cervical lordosis [CL] > 15°) (n = 129). Sagittal parameters were evaluated preoperatively and in the early postoperative window (6 weeks to 6 months postoperatively) and compared with asymptomatic control patients. Adult cervical deformity patients were further stratified by degree of cervical kyphosis (severe kyphosis, C2-T3 Cobb angle ≤ -30°; moderate kyphosis, ≤ 0°; and minimal kyphosis, > 0°) and severity of sagittal malalignment (severe malalignment, sagittal vertical axis T3-S1 ≤ -60 mm; moderate malalignment, ≤ 20 mm; and minimal malalignment > 20 mm)., Results: Compared with asymptomatic control patients, cervical deformity was associated with increased C0-2 lordosis (32.9° vs 23.6°), T1S (33.5° vs 28.0°), thoracolumbar junction kyphosis (T10-L2 Cobb angle -7.0° vs -1.7°), and pelvic tilt (PT) (19.7° vs 15.9°) (p < 0.01). Cervicothoracic kyphosis was correlated with C0-2 lordosis (R = -0.57, p < 0.01) and lumbar lordosis (LL) (R = -0.20, p = 0.03). Cervical reconstruction resulted in decreased C0-2 lordosis, increased T1S, and increased thoracic and thoracolumbar junction kyphosis (p < 0.01). Patients with severe cervical kyphosis (n = 34) had greater C0-2 lordosis (p < 0.01) and postoperative reduction of C0-2 lordosis (p = 0.02) but no difference in PT. Severe cervical kyphosis was also associated with a greater increase in thoracic and thoracolumbar junction kyphosis postoperatively (p = 0.01). Patients with severe sagittal malalignment (n = 52) had decreased PT (p = 0.01) and increased LL (p < 0.01), as well as a greater postoperative reduction in LL (p < 0.01)., Conclusions: Adult cervical deformity is associated with upper cervical hyperlordotic compensation and thoracic hypokyphosis. In the setting of increased kyphotic deformity and sagittal malalignment, thoracolumbar junction kyphosis and lumbar hyperlordosis develop to restore normal center of gravity. There was no consistent compensatory pelvic retroversion or anteversion among the adult cervical deformity patients in this cohort.

Objective: The objective of this study was to use an unsupervised cluster approach to identify patterns of operative adult spinal deformity (ASD) and compare the perioperative outcomes of these groups., Methods: A multicenter data set included patients with complex surgical ASD, including those with severe deformities, significant surgical complexity, or advanced age who underwent a multilevel fusion. An unsupervised cluster analysis allowing for 10% outliers was used to identify different deformity patterns. The perioperative outcomes of these clusters were then compared using ANOVA, Kruskal-Wallis, and chi-square tests, with p values < 0.05 considered significant., Results: Two hundred eighty-six patients were classified into four clusters of deformity patterns: hyper-thoracic kyphosis (hyper-TK), severe coronal, severe sagittal, and moderate sagittal. Hyper-TK patients had the lowest disability (mean Oswestry Disability Index [ODI] 32.9 ± 17.1) and pain scores (median numeric rating scale [NRS] back score 6, leg score 1). The severe coronal cluster had moderate functional impairment (mean physical component score 34.4 ± 12.3) and pain (median NRS back score 7, leg score 4) scores. The severe sagittal cluster had the highest levels of disability (mean ODI 49.3 ± 15.6) and low appearance scores (mean 2.3 ± 0.7). The moderate cluster (mean 68.8 ± 7.8 years) had the highest pain interference subscores on the Patient-Reported Outcomes Measurement Information System (mean 65.2 ± 5.8). Overall 30-day adverse events were equivalent among the four groups. Fusion to the pelvis was most common in the moderate sagittal (89.4%) and severe sagittal (97.5%) clusters. The severe coronal cluster had more osteotomies per case (median 11, IQR 6.5-14) and a higher rate of 30-day implant-related complications (5.5%). The severe sagittal and hyper-TK clusters had more three-column osteotomies (43% and 32.3%, respectively). Hyper-TK patients had shorter hospital stays., Conclusions: This cohort of patients with complex ASD surgeries contained four natural clusters of deformity, each with distinct perioperative outcomes.

Objective: Osteoporosis has significant implications in spine fusion surgery, for which reduced spinal bone mineral density (BMD) can result in complications and poorer outcomes. Currently, dual-energy x-ray absorptiometry (DEXA) is the gold standard for radiographic diagnosis of osteoporosis, although DEXA accuracy may be limited by the presence of degenerative spinal pathology. In recent years, there has been an evolving interest in using alternative imaging, including CT and MRI, to assess BMD. In this systematic review of the literature, the authors assessed the use and effectiveness of MRI, opportunistic CT (oCT), and quantitative CT (qCT) to measure BMD., Methods: In accordance with the PRISMA guidelines, the authors conducted a systematic search for articles posted on PubMed between the years 2000 and 2022 by using the keywords "opportunistic CT, quantitative CT, MRI" AND "bone density" AND "spine." Inclusion criteria consisted of articles written in English that reported studies pertaining to human or cadaveric subjects, and studies including a measure of spinal BMD. Articles not related to spinal BMD, osteoporosis, or spinal surgery or reports of studies that did not include the use of spinal MRI or CT were excluded. Key study outcomes were extracted from included articles, and qualitative analysis was subsequently performed., Results: The literature search yielded 302 articles. Forty-two articles reported studies that met the final inclusion criteria. Eighteen studies utilized MRI protocols to correlate spinal BMD with vertebral bone quality scores, M-scores, and quantitative perfusion markers. Eight studies correlated oCT with spinal BMD, and 16 studies correlated qCT with spinal BMD. With oCT and qCT imaging, there was consensus that Hounsfield unit (HU) values > 160 demonstrated significant reduction in risk of osteoporosis, whereas HU values < 110 were significantly correlated with osteoporosis., Conclusions: Osteoporosis is increasingly recognized as a significant risk factor for complications after spinal fusion surgery. Consequently, preoperative assessment of BMD is a critical factor to consider in planning surgical treatment. Although DEXA has been the gold standard for BMD measurement, other imaging modalities, including MRI, oCT, and qCT, appear to be viable alternatives and may offer cost and time savings.

Objective: Revision surgery is often necessary for adult spinal deformity (ASD) patients. Satisfaction with management is an important component of health-related quality of life. The authors hypothesized that patients who underwent multiple revision surgeries following ASD correction would exhibit lower self-reported satisfaction scores., Methods: This was a retrospective cohort study of 668 patients who underwent ASD surgery and were eligible for a minimum 2-year follow-up. Visits were stratified by occurrence prior to the index surgery (period 0), after the index surgery only (period 1), after the first revision only (period 2), and after the second revision only (period 3). Patients were further stratified by prior spine surgery before their index surgery. Scoliosis Research Society-22 (SRS-22r) health-related quality-of-life satisfaction subscore and total satisfaction scores were evaluated at all periods using multiple linear regression and adjustment for age, sex, and Charlson Comorbidity Index., Results: In total, 46.6% of the study patients had undergone prior spine surgery before their index surgery. The overall revision rate was 21.3%. Among patients with no spine surgery prior to the index surgery, SRS-22r satisfaction scores increased from period 0 to 1 (from 2.8 to 4.3, p < 0.0001), decreased after one revision from period 1 to 2 (4.3 to 3.9, p = 0.0004), and decreased further after a second revision from period 2 to 3 (3.9 to 3.3, p = 0.0437). Among patients with spine surgery prior to the index procedure, SRS-22r satisfaction increased from period 0 to 1 (2.8 to 4.2, p < 0.0001) and decreased from period 1 to 2 (4.2 to 3.8, p = 0.0011). No differences in follow-up time from last surgery were observed (all p > 0.3). Among patients with multiple revisions, 40% experienced rod fracture, 40% proximal junctional kyphosis, and 33% pseudarthrosis., Conclusions: Among patients undergoing ASD surgery, revision surgery is associated with decreased satisfaction, and multiple revisions are associated with additive detriment to satisfaction among patients initially undergoing primary surgery. These findings have direct implications for preoperative patient counseling and establishment of postoperative expectations.

Objective: Hyperextension of C0-2 is a debilitating compensatory mechanism used to maintain horizontal gaze, analogous to high pelvic tilt in the lumbopelvic complex to maintain an upright posture. This study aims to investigate the impact of cervical deformity (CD) correction on this hyperextension. The authors hypothesize that correction of cervical sagittal malalignment allows for relaxation of C0-2 hyperextension and improved clinical outcomes., Methods: A retrospective review was conducted of a multicenter database of patients with CD undergoing spinal realignment and fusion caudal to C2 and cephalad to the pelvis. Range of motion (ROM) and reserve of extension (ROE) were calculated across C2-7 and C0-2. The association between C2-7 correction and change in C0-2 ROE was investigated while controlling for horizontal gaze, followed by stratification into ΔC2-7 percentiles., Results: Sixty-five patients were included (mean age 61.8 ± 9.6 years, 68% female). At baseline, patients had cervical kyphosis (C2-7, -11.7° ± 18.2°; T1 slope-cervical lordosis mismatch, 38.6° ± 18.6°), negative global alignment (sagittal vertical axis [SVA] -12.8 ± 71.2 mm), and hyperlordosis at C0-2 (mean 33.2° ± 11.8°). The mean ROM was 25.7° ± 17.7° and 21.3° ± 9.9° at C2-7 and C0-2, respectively, with an ROE of approximately 9° for each segment. Limited C0-2 ROM and ROE correlated with the Neck Disability Index (r = -0.371 and -0.394, p < 0.01). The mean number of levels fused was 7.0 ± 3.1 (24.6% anterior, 43.1% posterior), with 87.7% undergoing at least an osteotomy. At 1 year, mean C2-7 increased to 5.5° ± 13.4°, SVA became neutral (11.5 ± 54.8 mm), C0-2 hyperlordosis decreased to 27.8° ± 11.7°, and thoracic kyphosis (TK) increased to -49.4° ± 18.1° (all p < 0.001). Concurrently, mean C0-2 ROM increased to 27.6° ± 8.1° and C2-7 ROM decreased significantly to 9.0° ± 12.3° without a change in ROE. Controlling for horizontal gaze, change in C2-7 lordosis significantly correlated with increased TK (r = -0.617, p < 0.001), decreased C0-2 (r = -0.747, p < 0.001), and increased C0-2 ROE (r = 0.550, p = 0.002)., Conclusions: CD correction can significantly impact cephalad and caudal compensation in the upper cervical and thoracic spine. Restoration of cervical alignment resulted in increased C0-2 ROE and TK and was also associated with improved clinical outcome.

Objective: The current literature has primarily focused on the 2-year outcomes of operative adult spinal deformity (ASD) treatment. Longer term durability is important given the invasiveness, complications, and costs of these procedures. The aim of this study was to assess minimum 3-year outcomes and complications of ASD surgery., Methods: Operatively treated ASD patients were assessed at baseline, follow-up, and through mailings. Patient-reported outcome measures (PROMs) included scores on the Oswestry Disability Index (ODI), Scoliosis Research Society-22r (SRS-22r) questionnaire, mental component summary (MCS) and physical component summary (PCS) of the SF-36, and numeric rating scale (NRS) for back and leg pain. Complications were classified as perioperative (≤ 90 days), delayed (90 days to 2 years), and long term (≥ 2 years). Analyses focused on patients with minimum 3-year follow-up., Results: Of 569 patients, 427 (75%) with minimum 3-year follow-up (mean ± SD [range] 4.1 ± 1.1 [3.0-9.6] years) had a mean age of 60.8 years and 75% were women. Operative treatment included a posterior approach for 426 patients (99%), with a mean ± SD 12 ± 4 fusion levels. Anterior lumbar interbody fusion was performed in 35 (8%) patients, and 89 (21%) underwent 3-column osteotomy. All PROMs improved significantly from baseline to last follow-up, including scores on ODI (45.4 to 30.5), PCS (31.0 to 38.5), MCS (45.3 to 50.6), SRS-22r total (2.7 to 3.6), SRS-22r activity (2.8 to 3.5), SRS-22r pain (2.3 to 3.4), SRS-22r appearance (2.4 to 3.5), SRS-22r mental (3.4 to 3.7), SRS-22r satisfaction (2.7 to 4.1), NRS for back pain (7.1 to 3.8), and NRS for leg pain (4.8 to 3.0) (all p < 0.001). Degradations in some outcome measures were observed between the 2-year and last follow-up evaluations, but the magnitudes of these degradations were modest and arguably not clinically significant. Overall, 277 (65%) patients had at least 1 complication, including 185 (43%) perioperative, 118 (27%) delayed, and 56 (13%) long term. Notably, the 142 patients who did not achieve 3-year follow-up were similar to the study patients in terms of demographic characteristics, deformities, and baseline PROMs and had similar rates and types of complications., Conclusions: This prospective multicenter analysis demonstrated that operative ASD treatment provided significant improvement of health-related quality of life at minimum 3-year follow-up (mean 4.1 years), suggesting that the benefits of surgery for ASD remain durable at longer follow-up. These findings should prove useful for counseling, cost-effectiveness assessments, and efforts to improve the safety of care.

Objective: Surgical correction of cervical deformity (CD) has been associated with superior alignment and functional outcomes. It has not yet been determined whether baseline or postoperative T1 slope (T1S) and C2 slope (C2S) correlate with health-related quality-of-life (HRQoL) metrics and radiographic complications, such as distal junctional kyphosis (DJK) and distal junctional failure (DJF). The objective of this study was to determine the impact of T1S and C2S deformity severity on HRQoL metrics and DJF development in patients with CD who underwent a cervical fusion procedure., Methods: All operative CD patients with upper instrumented vertebra above C7 and preoperative (baseline) and up to 2-year postoperative radiographic and HRQoL data were included. CD was defined as meeting at least one of the following radiographic parameters: C2-7 lordosis < -15°, TS1-cervical lordosis mismatch > 35°, segmental cervical kyphosis > 15° across any 3 vertebrae between C2 and T1, C2-7 sagittal vertical axis > 4 cm, McGregor's slope > 20°, or chin-brow vertical angle > 25°. Spearman's rank-order correlation and linear regression analysis assessed the impact of T1S and C2S on HRQoL metrics (Neck Disability Index [NDI], modified Japanese Orthopaedic Association [mJOA] scale, EuroQOL 5-Dimension Questionnaire [EQ-5D] visual analog scale [VAS] score, and numeric rating scale [NRS]-neck) and complications (DJK, DJF, reoperation). Logistic regression and a conditional inference tree (CIT) were used to determine radiographic thresholds for achieving optimal clinical outcome, defined as meeting good clinical outcome criteria (≥ 2 of the following: NDI < 20 or meeting minimal clinically important difference, mild myelopathy [mJOA score ≥ 14], and NRS-neck ≤ 5 or improved by ≥ 2 points), not undergoing reoperation, or developing DJF or mechanical complication by 2 years., Results: One hundred five patients with CD met inclusion criteria. By surgical approach, 14.7% underwent an anterior-only approach, 46.1% a posterior-only approach, and 39.2% combined anterior and posterior approaches. The mean baseline radiographic parameters were T1S 28.3° ± 14.5° and C2S 25.9° ± 17.5°. Significant associations were found between 3-month C2S and mJOA score (r = -0.248, p = 0.034), NDI (r = 0.399, p = 0.001), EQ-5D VAS (r = -0.532, p < 0.001), NRS-neck (r = 0.239, p = 0.040), and NRS-back (r = 0.264, p = 0.021), while significant correlation was also found between 3-month T1S and mJOA score (r = -0.314, p = 0.026), NDI (r = 0.445, p = 0.001), EQ-5D VAS (r = -0.347, p = 0.018), and NRS-neck (r = 0.269, p = 0.049). A significant correlation was also found between development of DJF and 3-month C2S (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.01-1.1, p = 0.015) as well as for T1S (OR 1.1, 95% CI 1.01-1.1, p = 0.023). Logistic regression with CIT identified thresholds for optimal outcome by 2 years: optimal 3-month T1S < 26° (OR 5.6) and C2S < 10° (OR 10.4), severe 3-month T1S < 45.5° (OR 0.2) and C2S < 38.0° (no patient above this threshold achieved optimal outcome; all p < 0.05). Patients below both optimal thresholds achieved rates of 0% for DJK and DJF, and 100% met optimal outcome., Conclusions: The severity of CD, defined by T1S and C2S at baseline and especially at 3 months, can be predictive of postoperative functional improvement and occurrence of worrisome complications in patients with CD, necessitating the use of thresholds in surgical planning to achieve optimal outcomes.

Objective: Minimally invasive surgery (MIS) for adult spinal deformity (ASD) can offer deformity correction with less tissue manipulation and damage. However, the impact of obesity on clinical outcomes and radiographic correction following MIS for ASD is poorly understood. The goal of this study was to determine the role, if any, that obesity has on radiographic correction and health-related quality-of-life measures in MIS for ASD., Methods: Data were collected from a multicenter database of MIS for ASD. This was a retrospective review of a prospectively collected database. Patient inclusion criteria were age ≥ 18 years and coronal Cobb angle ≥ 20°, pelvic incidence-lumbar lordosis mismatch ≥ 10°, or sagittal vertical axis (SVA) > 5 cm. A group of patients with body mass index (BMI) < 30 kg/m2 was the control cohort; BMI ≥ 30 kg/m2 was used to define obesity. Obesity cohorts were categorized into BMI 30-34.99 and BMI ≥ 35. All patients had at least 1 year of follow-up. Preoperative and postoperative health-related quality-of-life measures and radiographic parameters, as well as complications, were compared via statistical analysis., Results: A total of 106 patients were available for analysis (69 control, 17 in the BMI 30-34.99 group, and 20 in the BMI ≥ 35 group). The average BMI was 25.24 kg/m2 for the control group versus 32.46 kg/m2 (p < 0.001) and 39.5 kg/m2 (p < 0.001) for the obese groups. Preoperatively, the BMI 30-34.99 group had significantly more prior spine surgery (70.6% vs 42%, p = 0.04) and worse preoperative numeric rating scale leg scores (7.71 vs 5.08, p = 0.001). Postoperatively, the BMI 30-34.99 cohort had worse Oswestry Disability Index scores (33.86 vs 23.55, p = 0.028), greater improvement in numeric rating scale leg scores (-4.88 vs -2.71, p = 0.012), and worse SVA (51.34 vs 26.98, p = 0.042) at 1 year postoperatively. Preoperatively, the BMI ≥ 35 cohort had significantly worse frailty (4.5 vs 3.27, p = 0.001), Oswestry Disability Index scores (52.9 vs 44.83, p = 0.017), and T1 pelvic angle (26.82 vs 20.71, p = 0.038). Postoperatively, after controlling for differences in frailty, the BMI ≥ 35 cohort had significantly less improvement in their Scoliosis Research Society-22 outcomes questionnaire scores (0.603 vs 1.05, p = 0.025), higher SVA (64.71 vs 25.33, p = 0.015) and T1 pelvic angle (22.76 vs 15.48, p = 0.029), and less change in maximum Cobb angle (-3.93 vs -10.71, p = 0.034) at 1 year. The BMI 30-34.99 cohort had significantly more infections (11.8% vs 0%, p = 0.004). The BMI ≥ 35 cohort had significantly more implant complications (30% vs 11.8%, p = 0.014) and revision surgery within 90 days (5% vs 1.4%, p = 0.034)., Conclusions: Obese patients who undergo MIS for ASD have less correction of their deformity, worse quality-of-life outcomes, more implant complications and infections, and an increased rate of revision surgery compared with their nonobese counterparts, although both groups benefit from surgery. Appropriate counseling should be provided to obese patients.

Objective: This retrospective cohort study aimed to develop a formal predictive model distinguishing between symptomatic and asymptomatic distal junctional kyphosis (DJK). In this study the authors identified a DJK rate of 32.2%. Predictive models were created that can be used with high reliability to help distinguish between severe symptomatic DJK and mild asymptomatic DJK through the use of surgical factors, radiographic parameters, and patient variables., Methods: Patients with cervical deformity (CD) were stratified into asymptomatic and symptomatic DJK groups. Symptomatic: 1) DJK angle (DJKA) > 10° and either reoperation due to DJK or > 1 new-onset neurological sequela related to DJK; or 2) either a DJKA > 20° or ∆DJKA > 20°. Asymptomatic: ∆DJK > 10° in the absence of neurological sequelae. Stepwise logistic regressions were used to identify factors associated with these types of DJK. Decision tree analysis established cutoffs., Results: A total of 99 patients with CD were included, with 32.2% developing DJK (34.3% asymptomatic, 65.7% symptomatic). A total of 37.5% of asymptomatic patients received a reoperation versus 62.5% symptomatic patients. Multivariate analysis identified independent baseline factors for developing symptomatic DJK as follows: pelvic incidence (OR 1.02); preoperative cervical flexibility (OR 1.04); and combined approach (OR 6.2). Having abnormal hyperkyphosis in the thoracic spine, more so than abnormal cervical lordosis, was a factor for developing symptomatic disease when analyzed against asymptomatic patients (OR 1.2). Predictive modeling identified factors that were predictive of symptomatic versus no DJK, as follows: myelopathy (modified Japanese Orthopaedic Association score 12-14); combined approach; uppermost instrumented vertebra C3 or C4; preoperative hypermobility; and > 7 levels fused (area under the curve 0.89). A predictive model for symptomatic versus asymptomatic disease (area under the curve 0.85) included being frail, T1 slope minus cervical lordosis > 20°, and a pelvic incidence > 46.3°. Controlling for baseline deformity and disability, symptomatic patients had a greater cervical sagittal vertical axis (4-8 cm: 47.6% vs 27%) and were more malaligned according to their Scoliosis Research Society sagittal vertical axis measurement (OR 0.1) than patients without DJK at 1 year (all p < 0.05). Despite their symptomatology and higher reoperation rate, outcomes equilibrated in the symptomatic cohort at 1 year following revision., Conclusions: Overall, 32.2% of patients with CD suffered from DJK. Symptomatic DJK can be predicted with high reliability. It can be further distinguished from asymptomatic occurrences by taking into account pelvic incidence and baseline cervicothoracic deformity severity.

Objective: Cervical deformity (CD) is a complex condition with a clear impact on patient quality of life, which can be improved with surgical treatment. Previous study following thoracolumbar surgery demonstrated a spontaneous and maintained improvement in cervical alignment following lumbar pedicle subtraction osteotomy (PSO). In this study the authors aimed to investigate the complementary questions of whether cervical alignment induces a change in global alignment and whether this change stabilizes over time., Methods: To analyze spontaneous changes, this study included only patients with at least 5 levels remaining unfused following surgery. After data were obtained for the entire cohort, repeated-measures analyses were conducted between preoperative baseline and 3-month and 1-year follow-ups with a post hoc analysis and Bonferroni correction. A subanalysis of patients with 2-year follow-up was performed., Results: One-year follow-up data were available for 121 of 168 patients (72%), and 89 patients had at least 5 levels remaining unfused following surgery. Preoperatively there was a moderate anterior cervical alignment (C2-7, -7.7° [kyphosis]; T1 slope minus cervical lordosis, 37.1°; cervical sagittal vertebral axis [cSVA], 37 mm) combined with a posterior global alignment (SVA, -8 mm) with lumbar hyperextension (pelvic incidence [PI] minus lumbar lordosis [LL] mismatch [PI-LL], -0.6°). Patients underwent a significant correction of the cervical alignment (median ΔC2-7, 13.6°). Simultaneously, PI-LL, T1 pelvic angle (TPA), and SVA increased significantly (all p < 0.05) between baseline and 3-month and 1-year follow-ups. Post hoc analysis demonstrated that all of the changes occurred between baseline and 3 months. Subanalysis of patients with complete 2-year follow-up demonstrated similar results, with stable postoperative thoracolumbar alignment achieved at 3 months., Conclusions: Correction of cervical malalignment can have a significant impact on thoracolumbar regional and global alignment. Peak relaxation of compensatory mechanisms is achieved by the 3-month follow-up and tends to remain stable. Subanalysis with 2-year data further supports this finding. These findings can help to identify when the results of cervical surgery on global alignment can be best evaluated.

Objective: The authors' objective was to determine whether preoperative lateral extension cervical spine radiography can be used to predict osteotomy type and postoperative alignment parameters after cervical spine deformity surgery., Methods: A total of 106 patients with cervical spine deformity were reviewed. Radiographic parameters on preoperative cervical neutral and extension lateral radiography were compared with 3-month postoperative radiographic alignment parameters. The parameters included T1 slope, C2 slope, C2-7 cervical lordosis, cervical sagittal vertical axis, and T1 slope minus cervical lordosis. Associations of radiographic parameters with osteotomy type and surgical approach were also assessed., Results: On extension lateral radiography, patients who underwent lower grade osteotomy had significantly lower T1 slope, T1 slope minus cervical lordosis, cervical sagittal vertical axis, and C2 slope. Patients who achieved more normal parameters on extension lateral radiography were more likely to undergo surgery via an anterior approach. Although baseline parameters were significantly different between neutral lateral and extension lateral radiographs, 3-month postoperative lateral and preoperative extension lateral radiographs were statistically similar for T1 slope minus cervical lordosis and C2 slope., Conclusions: Radiographic parameters on preoperative extension lateral radiography were significantly associated with surgical approach and osteotomy grade and were similar to those on 3-month postoperative lateral radiography. These results demonstrated that extension lateral radiography is useful for preoperative planning and predicting postoperative alignment.

Objective: Deterioration of global coronal alignment (GCA) may be associated with worse outcomes after adult spinal deformity (ASD) surgery. The impact of fusion length and upper instrumented vertebra (UIV) selection on patients with this complication is unclear. The authors' objective was to compare outcomes between long sacropelvic fusion with upper-thoracic (UT) UIV and those with lower-thoracic (LT) UIV in patients with worsening GCA ≥ 1 cm., Methods: This was a retrospective analysis of a prospective multicenter database of consecutive ASD patients. Index operations involved instrumented fusion from sacropelvis to thoracic spine. Global coronal deterioration was defined as worsening GCA ≥ 1 cm from preoperation to 2-year follow-up., Results: Of 875 potentially eligible patients, 560 (64%) had complete 2-year follow-up data, of which 144 (25.7%) demonstrated worse GCA at 2-year postoperative follow-up (35.4% of UT patients vs 64.6% of LT patients). At baseline, UT patients were younger (61.6 ± 9.9 vs 64.5 ± 8.6 years, p = 0.008), a greater percentage of UT patients had osteoporosis (35.3% vs 16.1%, p = 0.009), and UT patients had worse scoliosis (51.9° ± 22.5° vs 32.5° ± 16.3°, p < 0.001). Index operations were comparable, except UT patients had longer fusions (16.4 ± 0.9 vs 9.7 ± 1.2 levels, p < 0.001) and operative duration (8.6 ± 3.2 vs 7.6 ± 3.0 hours, p = 0.023). At 2-year follow-up, global coronal deterioration averaged 2.7 ± 1.4 cm (1.9 to 4.6 cm, p < 0.001), scoliosis improved (39.3° ± 20.8° to 18.0° ± 14.8°, p < 0.001), and sagittal spinopelvic alignment improved significantly in all patients. UT patients maintained smaller positive C7 sagittal vertical axis (2.7 ± 5.7 vs 4.7 ± 5.7 cm, p = 0.014). Postoperative 2-year health-related quality of life (HRQL) significantly improved from baseline for all patients. HRQL comparisons demonstrated that UT patients had worse Scoliosis Research Society-22r (SRS-22r) Activity (3.2 ± 1.0 vs 3.6 ± 0.8, p = 0.040) and SRS-22r Satisfaction (3.9 ± 1.1 vs 4.3 ± 0.8, p = 0.021) scores. Also, fewer UT patients improved by ≥ 1 minimal clinically important difference in numerical rating scale scores for leg pain (41.3% vs 62.7%, p = 0.020). Comparable percentages of UT and LT patients had complications (208 total, including 53 reoperations, 77 major complications, and 78 minor complications), but the percentage of reoperated patients was higher among UT patients (35.3% vs 18.3%, p = 0.023). UT patients had higher reoperation rates of rod fracture (13.7% vs 2.2%, p = 0.006) and pseudarthrosis (7.8% vs 1.1%, p = 0.006) but not proximal junctional kyphosis (9.8% vs 8.6%, p = 0.810)., Conclusions: In ASD patients with worse 2-year GCA after long sacropelvic fusion, UT UIV was associated with worse 2-year HRQL compared with LT UIV. This may suggest that residual global coronal malalignment is clinically less tolerated in ASD patients with longer fusion to the proximal thoracic spine. These results may inform operative planning and improve patient counseling.

Objective: Few studies have compared fractional curve correction after long fusion between transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) for adult symptomatic thoracolumbar/lumbar scoliosis (ASLS). The objective of this study was to compare fractional correction, health-related quality of life (HRQL), and complications associated with L4-S1 TLIF versus those of ALIF as an operative treatment of ASLS., Methods: The authors retrospectively analyzed a prospective multicenter adult spinal deformity database. Inclusion required a fractional curve ≥ 10°, a thoracolumbar/lumbar curve ≥ 30°, index TLIF or ALIF performed at L4-5 and/or L5-S1, and a minimum 2-year follow-up. TLIF and ALIF patients were propensity matched according to the number and type of interbody fusion at L4-S1., Results: Of 135 potentially eligible consecutive patients, 106 (78.5%) achieved the minimum 2-year follow-up (mean ± SD age 60.6 ± 9.3 years, 85% women, 44.3% underwent TLIF, and 55.7% underwent ALIF). Index operations had mean ± SD 12.2 ± 3.6 posterior levels, 86.6% of patients underwent iliac fixation, 67.0% underwent TLIF/ALIF at L4-5, and 84.0% underwent TLIF/ALIF at L5-S1. Compared with TLIF patients, ALIF patients had greater cage height (10.9 ± 2.1 mm for TLIF patients vs 14.5 ± 3.0 mm for ALIF patients, p = 0.001) and lordosis (6.3° ± 1.6° for TLIF patients vs 17.0° ± 9.9° for ALIF patients, p = 0.001) and longer operative duration (6.7 ± 1.5 hours for TLIF patients vs 8.9 ± 2.5 hours for ALIF patients, p < 0.001). In all patients, final alignment improved significantly in terms of the fractional curve (20.2° ± 7.0° to 6.9° ± 5.2°), maximum coronal Cobb angle (55.0° ± 14.8° to 23.9° ± 14.3°), C7 sagittal vertical axis (5.1 ± 6.2 cm to 2.3 ± 5.4 cm), pelvic tilt (24.6° ± 8.1° to 22.7° ± 9.5°), and lumbar lordosis (32.3° ± 18.8° to 51.4° ± 14.1°) (all p < 0.05). Matched analysis demonstrated comparable fractional correction (-13.6° ± 6.7° for TLIF patients vs -13.6° ± 8.1° for ALIF patients, p = 0.982). In all patients, final HRQL improved significantly in terms of Oswestry Disability Index (ODI) score (42.4 ± 16.3 to 24.2 ± 19.9), physical component summary (PCS) score of the 36-item Short-Form Health Survey (32.6 ± 9.3 to 41.3 ± 11.7), and Scoliosis Research Society-22r score (2.9 ± 0.6 to 3.7 ± 0.7) (all p < 0.05). Matched analysis demonstrated worse ODI (30.9 ± 21.1 for TLIF patients vs 17.9 ± 17.1 for ALIF patients, p = 0.017) and PCS (38.3 ± 12.0 for TLIF patients vs 45.3 ± 10.1 for ALIF patients, p = 0.020) scores for TLIF patients at the last follow-up (despite no differences in these parameters at baseline). The rates of total complications were similar (76.6% for TLIF patients vs 71.2% for ALIF patients, p = 0.530), but significantly more TLIF patients had rod fracture (28.6% of TLIF patients vs 7.1% of ALIF patients, p = 0.036). Multiple regression analysis demonstrated that a 1-mm increase in L4-5 TLIF cage height led to a 2.2° reduction in L4 coronal tilt (p = 0.011), and a 1° increase in L5-S1 ALIF cage lordosis led to a 0.4° increase in L5-S1 segmental lordosis (p = 0.045)., Conclusions: Operative treatment of ASLS with L4-S1 TLIF versus ALIF demonstrated comparable mean fractional curve correction (66.7% vs 64.8%), despite use of significantly larger, more lordotic ALIF cages. TLIF cage height had a significant impact on leveling L4 coronal tilt, whereas ALIF cage lordosis had a significant impact on restoration of lumbosacral lordosis. The advantages of TLIF may include reduced operative duration and hospitalization; however, associated HRQL was inferior and more rod fractures were detected in the TLIF patients included in this study.

Objective: Patients with nonoperative (N-Op) adult spinal deformity (ASD) have inferior long-term spinopelvic alignment and clinical outcomes. Predictors of lower quality-of-life measures in N-Op populations have yet to be sufficiently investigated. The aim of this study was to identify patient-related factors and radiographic parameters associated with inferior health-related quality-of-life (HRQOL) scores in N-Op ASD patients., Methods: N-Op ASD patients with complete radiographic and outcome data at baseline and 2 years were included. N-Op patients and operative (Op) patients were propensity score matched for baseline disability and deformity. Patient-related factors and radiographic alignment parameters (pelvic tilt [PT], sagittal vertical axis [SVA], pelvic incidence [PI]-lumbar lordosis [LL] mismatch, mismatch between cervical lordosis and T1 segment slope [TS-CL], cervical-thoracic pelvic angle [PA], and others) at baseline and 2 years were analyzed as predictors for moderate to severe 2-year Oswestry Disability Index (ODI > 20) and failing to meet the minimal clinically importance difference (MCID) for 2-year Scoliosis Research Society Outcomes Questionnaire (SRS) scores (< 0.4 increase from baseline). Conditional inference decision trees identified predictors of each HRQOL measure and established cutoffs at which factors have a global effect. Random forest analysis (RFA) generated 5000 conditional inference trees to compute a variable importance table for top predictors of inferior HRQOL. Statistical significance was set at p < 0.05., Results: Six hundred sixty-two patients with ASD (331 Op patients and 331 N-Op patients) with complete radiographic and HRQOL data at their 2-year follow-up were included. There were no differences in demographics, ODI, and Schwab deformity modifiers between groups at baseline (all p > 0.05). N-Op patients had higher 2-year ODI scores (27.9 vs 20.3, p < 0.001), higher rates of moderate to severe disability (29.3% vs 22.4%, p = 0.05), lower SRS total scores (3.47 vs 3.91, p < 0.001), and higher rates of failure to reach SRS MCID (35.3% vs 15.7%, p < 0.001) than Op patients at 2 years. RFA ranked the top overall predictors for moderate to severe ODI at 2 years for N-Op patients as follows: 1) frailty index > 2.8, 2) BMI > 35 kg/m2, T4PA > 28°, and 4) Charlson Comorbidity Index > 1. Top radiographic predictors were T4PA > 28° and C2-S1 SVA > 93 mm. RFA also ranked the top overall predictors for failure to reach 2-year SRS MCID for N-Op patients, as follows: 1) T12-S1 lordosis > 53°, 2) cervical SVA (cSVA) > 28 mm, 3) C2-S1 angle > 14.5°, 4) TS-CL > 12°, and 5) PT > 23°. The top radiographic predictors were T12-S1 Cobb angle, cSVA, C2-S1 angle, and TS-CL., Conclusions: When controlling for baseline deformity in N-Op versus Op patients, subsequent deterioration in frailty, BMI, and radiographic progression over a 2-year follow-up were found to drive suboptimal patient-reported outcome measures in N-Op cohorts as measured by validated ODI and SRS clinical instruments.

Objective: The goal of this study was to assess the conversion rate from baseline cervical alignment to postoperative cervical deformity (CD) and the corresponding proximal junctional kyphosis (PJK) rate in patients undergoing thoracolumbar adult spinal deformity (ASD) surgery., Methods: The operative records of patients with ASD with complete radiographic data beginning at baseline up to 3 years were included. Patients with no baseline CD were postoperatively stratified by Ames CD criteria (T1 slope-cervical lordosis mismatch [TS-CL] > 20°, cervical sagittal vertical axis [cSVA] > 40 mm), where CD was defined as fulfilling one or more of the Ames criteria. Severe CD was defined as TS-CL > 30° or cSVA > 60 mm. Follow-up intervals were established after ASD surgery, with 6 weeks postoperatively defined as early; 6 weeks-1 year as intermediate; 1-2 years as late; and 2-3 years as long-term. Descriptive analyses and McNemar tests identified the CD conversion rate, PJK rate (< -10° change in uppermost instrumented vertebra and the superior endplate of the vertebra 2 levels superior to the uppermost instrumented vertebra), and specific alignment parameters that converted., Results: Two hundred sixty-six patients who underwent ASD surgery (mean age 59.7 years, 77.4% female) met the inclusion criteria; 103 of these converted postoperatively, and the remaining 163 did not meet conversion criteria. Thirty-eight patients converted to CD early, 26 converted at the intermediate time point, 29 converted late, and 10 converted in the long-term. At conversion, the early group had the highest mean TS-CL at 25.4° ± 8.5° and the highest mean cSVA at 33.6 mm-both higher than any other conversion group. The long-term group had the highest mean C2-7 angle at 19.7° and the highest rate of PJK compared to other groups (p = 0.180). The early group had the highest rate of conversion to severe CD, with 9 of 38 patients having severe TS-CL and only 1 patient per group converting to severe cSVA. Seven patients progressed from having only malaligned TS-CL at baseline (with normal cSVA) to CD with both malaligned TS-CL and cSVA by 6 weeks. Conversely, only 2 patients progressed from malaligned cSVA to both malaligned cSVA and TS-CL. By 1 year, the former number increased from 7 to 26 patients, and the latter increased from 2 to 20 patients. The revision rate was highest in the intermediate group at 48.0%, versus the early group at 19.2%, late group at 27.3%, and long-term group at 20% (p = 0.128). A higher pelvic incidence-lumbar lordosis mismatch, lower thoracic kyphosis, and a higher thoracic kyphosis apex immediately postoperatively significantly predicted earlier rather than later conversion (all p < 0.05). Baseline lumbar lordosis, pelvic tilt, and sacral slope were not significant predictors., Conclusions: Patients with ASD with normative cervical alignment who converted to CD after thoracolumbar surgery had varying radiographic findings based on timing of conversion. Although the highest number of patients converted within 6 weeks postoperatively, patients who converted in the late or long-term follow-up intervals had higher rates of concurrent PJK and greater radiographic progression.

Objective: Cervical deformity (CD) patients have severe disability and poor health status. However, little is known about how patients with rigid CD compare with those with flexible CD. The main objectives of this study were to 1) assess whether patients with rigid CD have worse baseline alignment and therefore require more aggressive surgical corrections and 2) determine whether patients with rigid CD have similar postoperative outcomes as those with flexible CD., Methods: This is a retrospective review of a prospective, multicenter CD database. Rigid CD was defined as cervical lordosis (CL) change < 10° between flexion and extension radiographs, and flexible CD was defined as a CL change ≥ 10°. Patients with rigid CD were compared with those with flexible CD in terms of cervical alignment and health-related quality of life (HRQOL) at baseline and at multiple postoperative time points. The patients were also compared in terms of surgical and intraoperative factors such as operative time, blood loss, and number of levels fused., Results: A total of 127 patients met inclusion criteria (32 with rigid and 95 with flexible CD, 63.4% of whom were females; mean age 60.8 years; mean BMI 27.4); 47.2% of cases were revisions. Rigid CD was associated with worse preoperative alignment in terms of T1 slope minus CL, T1 slope, C2-7 sagittal vertical axis (cSVA), and C2 slope (C2S; all p < 0.05). Postoperatively, patients with rigid CD had an increased mean C2S (29.1° vs 22.2°) at 3 months and increased cSVA (47.1 mm vs 37.5 mm) at 1 year (p < 0.05) compared with those with flexible CD. Patients with rigid CD had more posterior levels fused (9.5 vs 6.3), fewer anterior levels fused (1 vs 2.0), greater blood loss (1036.7 mL vs 698.5 mL), more 3-column osteotomies (40.6% vs 12.6%), greater total osteotomy grade (6.5 vs 4.5), and mean osteotomy grade per level (3.3 vs 2.1) (p < 0.05 for all). There were no significant differences in baseline HRQOL scores, the rate of distal junctional kyphosis, or major/minor complications between patients with rigid and flexible CD. Both rigid and flexible CD patients reported significant improvements from baseline to 1 year according to the numeric rating scale for the neck (-2.4 and -2.7, respectively), Neck Disability Index (-8.4 and -13.3, respectively), modified Japanese Orthopaedic Association score (0.1 and 0.6), and EQ-5D (0.01 and 0.05) (p < 0.05). However, HRQOL changes from baseline to 1 year did not differ between rigid and flexible CD patients., Conclusions: Patients with rigid CD have worse baseline cervical malalignment compared with those with flexible CD but do not significantly differ in terms of baseline disability. Rigid CD was associated with more invasive surgery and more aggressive corrections, resulting in increased operative time and blood loss. Despite more extensive surgeries, rigid CD patients had equivalent improvements in HRQOL compared with flexible CD patients. This study quantifies the importance of analyzing flexion-extension images, creating a prognostic tool for surgeons planning CD correction, and counseling patients who are considering CD surgery.

Objective: The impact of global coronal malalignment (GCM; C7 plumb line-midsacral offset) on adult spinal deformity (ASD) treatment outcomes is unclear. Here, the authors' primary objective was to assess surgical outcomes and complications in patients with severe GCM, with a secondary aim of investigating potential surgical target coronal thresholds for optimal outcomes., Methods: This is a retrospective analysis of a prospective multicenter database. Operative patients with severe GCM (≥ 1 SD above the mean) and a minimum 2-year follow-up were identified. Demographic, surgical, radiographic, health-related quality of life (HRQOL), and complications data were analyzed., Results: Of 691 potentially eligible operative patients (mean GCM 4 ± 3 cm), 80 met the criteria for severe GCM ≥ 7 cm. Of these, 62 (78%; mean age 63.7 ± 10.7 years, 81% women) had a minimum 2-year follow-up (mean follow-up 3.3 ± 1.1 years). The mean ASD-Frailty Index was 3.9 ± 1.5 (frail), 50% had undergone prior fusion, and 81% had concurrent severe sagittal spinopelvic deformity with GCM and C7-S1 sagittal vertical axis (SVA) positively correlated (r = 0.313, p = 0.015). Surgical characteristics included posterior-only (58%) versus anterior-posterior (42%) approach, mean fusion of 13.2 ± 3.8 levels, iliac fixation (90%), 3-column osteotomy (36%), operative duration of 8.3 ± 3.0 hours, and estimated blood loss of 2.3 ± 1.7 L. Final alignment and HRQOL significantly improved (p < 0.01): GCM, 11 to 4 cm; maximum coronal Cobb angle, 43° to 20°; SVA, 13 to 4 cm; pelvic tilt, 29° to 23°; pelvic incidence-lumbar lordosis mismatch, 31° to 5°; Oswestry Disability Index, 51 to 37; physical component summary of SF-36 (PCS), 29 to 37; 22-Item Scoliosis Research Society Patient Questionnaire (SRS-22r) Total, 2.6 to 3.5; and numeric rating scale score for back and leg pain, 7 to 4 and 5 to 3, respectively. Residual GCM ≥ 3 cm was associated with worse SRS-22r Appearance (p = 0.04) and SRS-22r Satisfaction (p = 0.02). The minimal clinically important difference and/or substantial clinical benefit (MCID/SCB) was met in 43%-83% (highest for SRS-22r Appearance [MCID 83%] and PCS [SCB 53%]). The severity of baseline GCM (≥ 2 SD above the mean) significantly impacted postoperative SRS-22r Satisfaction and MCID/SCB improvement for PCS. No significant partial correlations were demonstrated between GCM or SVA correction and HRQOL improvement. There were 89 total complications (34 minor and 55 major), 45 (73%) patients with ≥ 1 complication (most commonly rod fracture [19%] and proximal junctional kyphosis [PJK; 18%]), and 34 reoperations in 22 (35%) patients (most commonly for rod fracture and PJK)., Conclusions: Study results demonstrated that ASD surgery in patients with substantial GCM was associated with significant radiographic and HRQOL improvement despite high complication rates. MCID improvement was highest for SRS-22r Appearance/Self-Image. A residual GCM ≥ 3 cm was associated with a worse outcome, suggesting a potential coronal realignment target threshold to assist surgical planning.

Objective: The shared decision-making (SDM) process provides an opportunity to answer frequently asked questions (FAQs). The authors aimed to present a concise list of answers to FAQs to aid in SDM for adult spinal deformity (ASD) surgery., Methods: From a prospective, multicenter ASD database, patients enrolled between 2008 and 2016 who underwent fusions of 5 or more levels with a minimum 2-year follow-up were included. All deformity types were included to provide general applicability. The authors compiled a list of FAQs from patients undergoing ASD surgery and used a retrospective analysis to provide answers. All responses are reported as either the means or the proportions reaching the minimal clinically important difference at the 2-year follow-up interval., Results: Of 689 patients with ASD who were eligible for 2-year follow-up, 521 (76%) had health-related quality-of-life scores available at the time of that follow-up. The mean age at the initial surgery was 58.2 years, and 78% of patients were female. The majority (73%) underwent surgery with a posterior-only approach. The mean number of fused levels was 12.2. Revision surgery accounted for 48% of patients. The authors answered 12 FAQs as follows:1. Will my pain improve? Back and leg pain will both be reduced by approximately 50%.2. Will my activity level improve? Approximately 65% of patients feel improvement in their activity level.3. Will I feel better about myself? More than 70% of patients feel improvement in their appearance.4. Is there a chance I will get worse? 4.1% feel worse at 2 years postoperatively.5. What is the likelihood I will have a complication? 67.8% will have a major or minor complication, with 47.8% having a major complication.6. Will I need another surgery? 25.0% will have a reoperation within 2 years.7. Will I regret having surgery? 6.5% would not choose the same treatment.8. Will I get a blood transfusion? 73.7% require a blood transfusion.9. How long will I stay in the hospital? You need to stay 8.1 days on average.10. Will I have to go to the ICU? 76.0% will have to go to the ICU.11. Will I be able to return to work? More than 70% will be working at 1 year postoperatively.12. Will I be taller after surgery? You will be 1.1 cm taller on average., Conclusions: The above list provides concise, practical answers to FAQs encountered in the SDM process while counseling patients for ASD surgery.

Objective: It is being increasingly recognized that adult cervical deformity (ACD) is correlated with significant pain, myelopathy, and disability, and that patients who undergo deformity correction gain significant benefit. However, there are no defined thresholds of minimum clinically important difference (MCID) in Neck Disability Index (NDI) and modified Japanese Orthopaedic Association (mJOA) scores., Methods: Patients of interest were consecutive patients with ACD who underwent cervical deformity correction. ACD was defined as C2-7 sagittal Cobb angle ≥ 10° (kyphosis), C2-7 coronal Cobb angle ≥ 10° (cervical scoliosis), C2-7 sagittal vertical axis ≥ 4 cm, and/or chin-brow vertical angle ≥ 25°. Data were obtained from a consecutive cohort of patients from a multiinstitutional prospective database maintained across 13 sites. Distribution-based MCID, anchor-based MCID, and minimally detectable measurement difference (MDMD) were calculated., Results: A total of 73 patients met inclusion criteria and had sufficient 1-year follow-up. In the cohort, 42 patients (57.5%) were female. The mean age at the time of surgery was 62.23 years, and average body mass index was 29.28. The mean preoperative NDI was 46.49 and mJOA was 13.17. There was significant improvement in NDI at 1 year (46.49 vs 37.04; p = 0.0001). There was no significant difference in preoperative and 1-year mJOA (13.17 vs 13.7; p = 0.12). Using multiple techniques to yield MCID thresholds specific to the ACD population, the authors obtained values of 5.42 to 7.48 for the NDI, and 1.00 to 1.39 for the mJOA. The MDMD was 6.4 for the NDI, and 1.8 for the mJOA. Therefore, based on their results, the authors recommend using an MCID threshold of 1.8 for the mJOA, and 7.0 for the NDI in patients with ACD., Conclusions: The ACD-specific MCID thresholds for NDI and mJOA are similar to the reported MCID following surgery for degenerative cervical disease. Additional studies are needed to verify these findings. Nonetheless, the findings here will be useful for future studies evaluating the success of surgery for patients with ACD undergoing deformity correction.

Objective: Optimal patient selection for upper-thoracic (UT) versus lower-thoracic (LT) fusion during adult spinal deformity (ASD) correction is challenging. Radiographic and clinical outcomes following UT versus LT fusion remain incompletely understood. The purposes of this study were: 1) to evaluate demographic, radiographic, and surgical characteristics associated with choice of UT versus LT fusion endpoint; and 2) to evaluate differences in radiographic, clinical, and health-related quality of life (HRQOL) outcomes following UT versus LT fusion for ASD., Methods: Retrospective review of a prospectively collected multicenter ASD database was performed. Patients with ASD who underwent fusion from the sacrum/ilium to the LT (T9-L1) or UT (T1-6) spine were compared for demographic, radiographic, and surgical characteristics. Outcomes including proximal junctional kyphosis (PJK), reoperation, rod fracture, pseudarthrosis, overall complications, 2-year change in alignment parameters, and 2-year HRQOL metrics (Lumbar Stiffness Disability Index, Scoliosis Research Society-22r questionnaire, Oswestry Disability Index) were compared after controlling for confounding factors via multivariate analysis., Results: Three hundred three patients (169 LT, 134 UT) were evaluated. Independent predictors of UT fusion included greater thoracic kyphosis (odds ratio [OR] 0.97 per degree, p = 0.0098), greater coronal Cobb angle (OR 1.06 per degree, p < 0.0001), and performance of a 3-column osteotomy (3-CO; OR 2.39, p = 0.0351). While associated with longer operative times (ratio 1.13, p < 0.0001) and greater estimated blood loss (ratio 1.31, p = 0.0018), UT fusions resulted in greater sagittal vertical axis improvement (-59.5 vs -41.0 mm, p = 0.0035) and lower PJK rates (OR 0.49, p = 0.0457). No significant differences in postoperative HRQOL measures, reoperation, or overall complication rates were detected between groups (all p > 0.1)., Conclusions: Greater deformity and need for 3-CO increased the likelihood of UT fusion. Despite longer operative times and greater blood loss, UT fusions resulted in better sagittal correction and lower 2-year PJK rates following surgery for ASD. While continued surveillance is necessary, this information may inform patient counseling and surgical decision-making.

Objective: Cervical deformity (CD) correction is clinically challenging. There is a high risk of developing complications with these highly complex procedures. The aim of this study was to use baseline demographic, clinical, and surgical factors to predict a poor outcome following CD surgery., Methods: The authors performed a retrospective review of a multicenter prospective CD database. CD was defined as at least one of the following: cervical kyphosis (C2-7 Cobb angle > 10°), cervical scoliosis (coronal Cobb angle > 10°), C2-7 sagittal vertical axis (cSVA) > 4 cm, or chin-brow vertical angle (CBVA) > 25°. Patients were categorized based on having an overall poor outcome or not. Health-related quality of life measures consisted of Neck Disability Index (NDI), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale scores. A poor outcome was defined as having all 3 of the following categories met: 1) radiographic poor outcome: deterioration or severe radiographic malalignment 1 year postoperatively for cSVA or T1 slope-cervical lordosis mismatch (TS-CL); 2) clinical poor outcome: failing to meet the minimum clinically important difference (MCID) for NDI or having a severe mJOA Ames modifier; and 3) complications/reoperation poor outcome: major complication, death, or reoperation for a complication other than infection. Univariate logistic regression followed by multivariate regression models was performed, and internal validation was performed by calculating the area under the curve (AUC)., Results: In total, 89 patients with CD were included (mean age 61.9 years, female sex 65.2%, BMI 29.2 kg/m2). By 1 year postoperatively, 18 (20.2%) patients were characterized as having an overall poor outcome. For radiographic poor outcomes, patients' conditions either deteriorated or remained severe for TS-CL (73% of patients), cSVA (8%), horizontal gaze (34%), and global SVA (28%). For clinical poor outcomes, 80% and 60% of patients did not reach MCID for EQ-5D and NDI, respectively, and 24% of patients had severe symptoms (mJOA score 0-11). For the complications/reoperation poor outcome, 28 patients experienced a major complication, 11 underwent a reoperation, and 1 had a complication-related death. Of patients with a poor clinical outcome, 75% had a poor radiographic outcome; 35% of poor radiographic and 37% of poor clinical outcome patients had a major complication. A poor outcome was predicted by the following combination of factors: osteoporosis, baseline neurological status, use of a transition rod, number of posterior decompressions, baseline pelvic tilt, T2-12 kyphosis, TS-CL, C2-T3 SVA, C2-T1 pelvic angle (C2 slope), global SVA, and number of levels in maximum thoracic kyphosis. The final model predicting a poor outcome (AUC 86%) included the following: osteoporosis (OR 5.9, 95% CI 0.9-39), worse baseline neurological status (OR 11.4, 95% CI 1.8-70.8), baseline pelvic tilt > 20° (OR 0.92, 95% CI 0.85-0.98), > 9 levels in maximum thoracic kyphosis (OR 2.01, 95% CI 1.1-4.1), preoperative C2-T3 SVA > 5.4 cm (OR 1.01, 95% CI 0.9-1.1), and global SVA > 4 cm (OR 3.2, 95% CI 0.09-10.3)., Conclusions: Of all CD patients in this study, 20.2% had a poor overall outcome, defined by deterioration in radiographic and clinical outcomes, and a major complication. Additionally, 75% of patients with a poor clinical outcome also had a poor radiographic outcome. A poor overall outcome was most strongly predicted by severe baseline neurological deficit, global SVA > 4 cm, and including more of the thoracic maximal kyphosis in the construct.

Objective: Obesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the sagittal vertical axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes., Methods: The authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders., Results: Increasing BMI (compared to BMI < 18) was not associated with change of SVA at 1 year postsurgery. However, BMIs in the obese range of 30 to 34.9 kg/m2, compared to BMI < 18 at baseline, were associated with poorer outcomes as measured by the SRS-22 score (estimated change -0.47, 95% CI -0.93 to -0.01, p = 0.04). While BMIs > 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance., Conclusions: Baseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.

OBJECTIVEPseudarthrosis can occur following adult spinal deformity (ASD) surgery and can lead to instrumentation failure, recurrent pain, and ultimately revision surgery. In addition, it is one of the most expensive complications of ASD surgery. Risk factors contributing to pseudarthrosis in ASD have been described; however, a preoperative model predicting the development of pseudarthrosis does not exist. The goal of this study was to create a preoperative predictive model for pseudarthrosis based on demographic, radiographic, and surgical factors.METHODSA retrospective review of a prospectively maintained, multicenter ASD database was conducted. Study inclusion criteria consisted of adult patients (age ≥ 18 years) with spinal deformity and surgery for the ASD. From among 82 variables assessed, 21 were used for model building after applying collinearity testing, redundancy, and univariable predictor importance ≥ 0.90. Variables included demographic data along with comorbidities, modifiable surgical variables, baseline coronal and sagittal radiographic parameters, and baseline scores for health-related quality of life measures. Patients groups were determined according to their Lenke radiographic fusion type at the 2-year follow-up: bilateral or unilateral fusion (union) or pseudarthrosis (nonunion). A decision tree was constructed, and internal validation was accomplished via bootstrapped training and testing data sets. Accuracy and the area under the receiver operating characteristic curve (AUC) were calculated to evaluate the model.RESULTSA total of 336 patients were included in the study (nonunion: 105, union: 231). The model was 91.3% accurate with an AUC of 0.94. From 82 initial variables, the top 21 covered a wide range of areas including preoperative alignment, comorbidities, patient demographics, and surgical use of graft material.CONCLUSIONSA model for predicting the development of pseudarthrosis at the 2-year follow-up was successfully created. This model is the first of its kind for complex predictive analytics in the development of pseudarthrosis for patients with ASD undergoing surgical correction and can aid in clinical decision-making for potential preventative strategies.

OBJECTIVE Most cervical fixations for atlantoaxial dislocation (AAD) are bilateral and symmetric; however, in the setting of osseous and vascular deformity at the craniovertebral junction, asymmetrical and hybrid fixations are used as "salvage" techniques. Because of the rarity of these cases, hybrid cervical fixations for AAD have not been fully explored. The aim of this study was to evaluate the clinical feasibility and outcomes of posterior hybrid cervical fixations for AAD. METHODS Twenty-one AAD cases were retrospectively studied; 18 had cervical myelopathy with Japanese Orthopaedic Association (JOA) scores ranging from 9 to 16 (mean 13.5). Hybrid fixation techniques included unilateral pedicle screws, transarticular screws, C-2 laminar screws, cervical lateral mass screws, and spinous process screws. During the same period, 82 AAD cases, treated using symmetric traditional fixations, were analyzed as controls. RESULTS Atlantoaxial fixation was performed in 11 cases, while occiput-cervical fixation was used in 10 cases. All cases achieved solid osseous fusion. Anatomical reduction was achieved in 20 cases (95.2%). All 18 cases with myelopathy showed postoperative improvement, with JOA scores ranging from 13 to 17 (mean 15.5). Three cases (14.2%) experienced complications, including delayed wound healing, CSF leakage, and fixation loosening. Hybrid fixation techniques showed significantly greater estimated blood loss when compared with controls (208.1 ± 19.30 ml vs 139.63 ± 8.75 ml, p = 0.001). Operative duration (125.38 ± 6.29 min vs 119.41 ± 3.77 min, p = 0.464), complication rates (14.3% vs 4.9%, p = 0.148), and JOA improvement rates (61% ± 7% vs 49% ± 4%, p = 0.161) showed no significant differences. CONCLUSIONS For ADD with osseous or vascular deformity, posterior cervical reduction and stabilization can be achieved using hybrid techniques, resulting in comparable clinical results to symmetric traditional fixation.

OBJECTIVE Given the recent shift in health care toward quality reporting requirements and a greater emphasis on a cost-quality approach, patient stratification with respect to long-term outcomes and the use of health care resources is of increasing value. Stratification tools may be effective if they are simple and evidence based. The authors hypothesize that preoperative patient-reported activity levels might independently predict postoperative outcomes in patients with adult spinal deformity. METHODS This is a retrospective cohort. A total of 575 patients in a prospective adult spinal deformity surgical database were identified with complete data regarding the preoperative level of activity. Answers to question 5 of the Scoliosis Research Society-22r Patient Questionnaire (SRS-22r) were used to stratify patients into active and inactive groups. Outcomes were length of hospital stay (LOS), level of activity, and reaching the minimum clinically important difference (MCID) for SRS-22r domains and the Physical Component Summary (PCS) of the SF-36 at 2 years postoperatively. The 2 groups were compared with respect to several potential confounders. Covariates with p < 0.1 were controlled for. The impact of activity on LOS was assessed using multivariate negative binomial regression analysis. Multivariate logistic regression models additionally controlling for the respective baseline health-related quality of life (HRQOL) scores were used to assess the association between preoperative activity levels and reaching the MCID at 2 years postoperatively. RESULTS A total of 420 (73%) of the 575 patients who met the inclusion criteria had complete data at 2 years postoperatively. The inactive group was more likely to be significantly older, have a higher Charlson Comorbidity Index, worse baseline radiographic deformity, and greater correction of most radiographic parameters. After controlling for possible confounders, the active group had a significantly shorter LOS (incidence risk ratio 0.91, p = 0.043). After adding respective baseline HRQOL scores to the models, active patients were significantly more likely to reach the MCID for the SRS-22r pain domain (OR 1.72, p = 0.026) and PCS (OR 1.94, p = 0.013). Active patients were also significantly more likely to be active at 2 years postoperatively on multivariate analysis (OR 8.94, p < 0.001). CONCLUSIONS The authors' results show that patients who belong to the inactive group are likely to have a longer LOS and lower odds of reaching the MCID in HRQOL or being active at 2 years postoperatively. Inquiring about patients' preoperative activity levels might be a reliable and simple stratification tool in terms of long- and short-term outcomes in ASD patients.

OBJECTIVE Depression and anxiety have been demonstrated to have negative impacts on outcomes after spine surgery. In patients with cervical deformity (CD), the psychological and physiological burdens of the disease may overlap without clear boundaries. While surgery has a proven record of bringing about significant pain relief and decreased disability, the impact of depression and anxiety on recovery from cervical deformity corrective surgery has not been previously reported on in the literature. The purpose of the present study was to determine the effect of depression and anxiety on patients' recovery from and improvement after CD surgery. METHODS The authors conducted a retrospective review of a prospective, multicenter CD database. Patients with a history of clinical depression, in addition to those with current self-reported anxiety or depression, were defined as depressed (D group). The D group was compared with nondepressed patients (ND group) with a similar baseline deformity determined by propensity score matching of the cervical sagittal vertical axis (cSVA). Baseline demographic, comorbidity, clinical, and radiographic data were compared among patients using t-tests. Improvement of symptoms was recorded at 3 months, 6 months, and 1 year postoperatively. All health-related quality of life (HRQOL) scores collected at these follow-up time points were compared using t-tests. RESULTS Sixty-six patients were matched for baseline radiographic parameters: 33 with a history of depression and/or current depression, and 33 without. Depressed patients had similar age, sex, race, and radiographic alignment: cSVA, T-1 slope minus C2-7 lordosis, SVA, and T-1 pelvic angle (p > 0.05). Compared with nondepressed individuals, depressed patients had a higher incidence of osteoporosis (21.2% vs 3.2%, p = 0.028), rheumatoid arthritis (18.2% vs 3.2%, p = 0.012), and connective tissue disorders (18.2% vs 3.2%, p = 0.012). At baseline, the D group had greater neck pain (7.9 of 10 vs 6.6 on a Numeric Rating Scale [NRS], p = 0.015), lower mean EQ-5D scores (68.9 vs 74.7, p < 0.001), but similar Neck Disability Index (NDI) scores (57.5 vs 49.9, p = 0.063) and myelopathy scores (13.4 vs 13.9, p = 0.546). Surgeries performed in either group were similar in terms of number of levels fused, osteotomies performed, and correction achieved (baseline to 3-month measurements) (p < 0.05). At 3 months, EQ-5D scores remained lower in the D group (74.0 vs 78.2, p = 0.044), and NDI scores were similar (48.5 vs 39.0, p = 0.053). However, neck pain improved in the D group (NRS score of 5.0 vs 4.3, p = 0.331), and modified Japanese Orthopaedic Association (mJOA) scores remained similar (14.2 vs 15.0, p = 0.211). At 6 months and 1 year, all HRQOL scores were similar between the 2 cohorts. One-year measurements were as follows: NDI 39.7 vs 40.7 (p = 0.878), NRS neck pain score of 4.1 vs 5.0 (p = 0.326), EQ-5D score of 77.1 vs 78.2 (p = 0.646), and mJOA score of 14.0 vs 14.2 (p = 0.835). Anxiety/depression levels reported on the EQ-5D scale were significantly higher in the depressed cohort at baseline, 3 months, and 6 months (all p < 0.05), but were similar between groups at 1 year postoperatively (1.72 vs 1.53, p = 0.416). CONCLUSIONS Clinical depression was observed in many of the study patients with CD. After matching for baseline deformity, depression symptomology resulted in worse baseline EQ-5D and pain scores. Despite these baseline differences, both cohorts achieved similar results in all HRQOL assessments 6 months and 1 year postoperatively, demonstrating no clinical impact of depression on recovery up until 1 year after CD surgery. Thus, a history of depression does not appear to have an impact on recovery from CD surgery.

OBJECTIVE Using 2 complication-reporting methods, the authors investigated the incidence of major medical complications and mortality in elderly patients after surgery for adult spinal deformity (ASD) during a 2-year follow-up period. METHODS The authors queried a multicenter, prospective, surgeon-maintained database (SMD) to identify patients 65 years or older who underwent surgical correction of ASD from 2008 through 2014 and had a minimum 2 years of follow-up (n = 153). They also queried a Centers for Medicare & Medicaid Services claims database (MCD) for patients 65 years or older who underwent fusion of 8 or more vertebral levels from 2005 through 2012 (n = 3366). They calculated cumulative rates of the following complications during the first 6 weeks after surgery: cerebrovascular accident, congestive heart failure, deep venous thrombosis, myocardial infarction, pneumonia, and pulmonary embolism. Significance was set at p < 0.05. RESULTS During the perioperative period, rates of major medical complications were 5.9% for pneumonia, 4.1% for deep venous thrombosis, 3.2% for pulmonary embolism, 2.1% for cerebrovascular accident, 1.8% for myocardial infarction, and 1.0% for congestive heart failure. Mortality rates were 0.9% at 6 weeks and 1.8% at 2 years. When comparing the SMD with the MCD, there were no significant differences in the perioperative rates of major medical complications except pneumonia. Furthermore, there were no significant intergroup differences in the mortality rates at 6 weeks or 2 years. The SMD provided greater detail with respect to deformity characteristics and surgical variables than the MCD. CONCLUSIONS The incidence of most major medical complications in the elderly after surgery for ASD was similar between the SMD and the MCD and ranged from 1% for congestive heart failure to 5.9% for pneumonia. These complications data can be valuable for preoperative patient counseling and informed consent.

OBJECTIVE It is becoming increasingly necessary for surgeons to provide evidence supporting cost-effectiveness of surgical treatment for cervical spine pathology. Anticipating surgical risk is critical in accurately evaluating the risk/benefit balance of such treatment. Determining the risk and cost-effectiveness of surgery, complications, revision procedures, and mortality rates are the most significant limitations. The purpose of this study was to determine independent risk factors for medical complications (MCs), surgical complications (SCs), revisions, and mortality rates following surgery for patients with cervical spine pathology. The most relevant risk factors were used to structure an index that will help quantify risk and anticipate failure for such procedures. METHODS The authors of this study performed a retrospective review of the National Inpatient Sample (NIS) database for patients treated surgically for cervical spine pathology between 2001 and 2010. Multivariate models were performed to calculate the odds ratio (OR) of the independent risk factors that led to MCs and repeated for SCs, revisions, and mortality. The models controlled for age (< and > 65 years old), sex, race, revision status (except for revision analysis), surgical approach, number of levels fused/re-fused (2-3, 4-8, ≥ 9), and osteotomy utilization. ORs were weighted based on their predictive category: 2 times for revision surgery predictors and 4 times for mortality predictors. Fifty points were distributed among the predictors based on their cumulative OR to establish a risk index. RESULTS Discharges for 362,989 patients with cervical spine pathology were identified. The mean age was 52.65 years, and 49.47% of patients were women. Independent risk factors included medical comorbidities, surgical parameters, and demographic factors. Medical comorbidities included the following: pulmonary circulation disorder, coagulopathy, metastatic cancer, renal failure, congestive heart failure, alcohol abuse, neurological disorder, nonmetastatic cancer, liver disease, rheumatoid arthritis/collagen vascular diseases, and chronic blood loss/anemia. Surgical parameters included posterior approach to fusion/re-fusion, ≥ 9 levels fused/re-fused, corpectomy, 4-8 levels fused/re-fused, and osteotomy; demographic variables included age ≥ 65 years. These factors increased the risk of at least 1 of MC, SC, revision, or mortality (risk of death). A total of 50 points were distributed among the factors based on the cumulative risk ratio of every factor in proportion to the total risk ratios. CONCLUSIONS This study proposed an index to quantify the potential risk of morbidity and mortality prior to surgical intervention for patients with cervical spine pathology. This index may be useful for surgeons in patient counseling efforts as well as for health insurance companies and future socioeconomics studies in assessing surgical risks and benefits for patients undergoing surgical treatment of the cervical spine.

OBJECTIVE The goal of this study was to compare inpatient morbidity and mortality after adult spinal deformity (ASD) surgery in teaching versus nonteaching hospitals in the US. METHODS The Nationwide Inpatient Sample was used to identify surgical patients with ASD between 2002 and 2011. Only patients > 21 years old and elective cases were included. Patient characteristics, inpatient morbidity, and inpatient mortality were compared between teaching and nonteaching hospitals. A multivariable logistic regression analysis was performed to examine the effect of hospital teaching status on surgical outcomes. RESULTS A total of 7603 patients were identified, with 61.2% (n = 4650) in the teaching hospital group and 38.8% (n = 2953) in the nonteaching hospital group. The proportion of patients undergoing revision procedures was significantly different between groups (5.2% in teaching hospitals vs 3.9% in nonteaching hospitals, p = 0.008). Likewise, complex procedures (defined as fusion of 8 or more segments and/or osteotomy) were more common in teaching hospitals (27.3% vs 21.7%, p < 0.001). Crude overall complication rates were similar in teaching hospitals (47.9%) compared with nonteaching hospitals (49.8%, p = 0.114). After controlling for patient characteristics, case complexity, and revision status, patients treated at teaching hospitals were significantly less likely to develop a complication when compared with patients treated at a nonteaching hospital (OR 0.89; 95% CI 0.82-0.98). The mortality rate was 0.4% in teaching hospitals and < 0.4% in nonteaching hospitals (p = 0.210). CONCLUSIONS Patients who undergo surgery for ASD at a teaching hospital may have significantly lower odds of complication development compared with patients treated at a nonteaching hospital.

Objective: A high prevalence of cervical deformity (CD) has been identified among adult patients with thoracolumbar spinal deformity undergoing surgical treatment. The clinical impact of this is uncertain. This study aimed to quantify the differences in patient-reported outcomes among patients with adult spinal deformity (ASD) based on presence of CD prior to treatment., Methods: A retrospective review was conducted of a multicenter prospective database of patients with ASD who underwent surgical treatment with 2-year follow-up. Patients were grouped by the presence of preoperative CD: 1) cervical positive sagittal malalignment (CPSM) C2-7 sagittal vertical axis ≥ 4 cm; 2) cervical kyphosis (CK) C2-7 angle > 0; 3) CPSM and CK (BOTH); and 4) no baseline CD (NONE). Health-related quality of life (HRQOL) scores included the Physical Component Summary and Mental Component Summary (PCS and MCS) scores of the 36-Item Short Form Health Survey (SF-36), Oswestry Disability Index (ODI), Scoliosis Research Society-22 questionnaire (SRS-22), and minimum clinically important difference (MCID) of these scores at 2 years. Standard radiographic measurements were conducted for cervical, thoracic, and thoracolumbar parameters., Results: One hundred eighty-two patients were included in this study: CPSM, 45; CK, 37; BOTH, 16; and NONE, 84. Patients with preoperative CD and those without had similar baseline thoracolumbar radiographic measurements and similar correction rates at 2 years. Patients with and without preoperative CD had similar baseline HRQOL and on average both groups experienced some HRQOL improvement. However, those with preoperative CPSM had significantly worse postoperative ODI, PCS, SRS-22 Activity, SRS-22 Appearance, SRS-22 Pain, SRS-22 Satisfaction, and SRS-22 Total score, and were less likely to meet MCID for ODI, PCS, SRS-22 Activity, and SRS-22 Pain scores with the following ORs and 95% CIs: ODI 0.19 (0.07-0.58), PCS 0.17 (0.06-0.47), SRS-22 Activity 0.23 (0.09-0.62), SRS-22 Pain 0.20 (0.08-0.53), and SRS-22 Appearance 0.34 (0.12-0.94). Preoperative CK did not have an effect on outcomes. Interestingly, despite correction of the thoracolumbar deformity, 53.3% and 51.4% of patients had persistent CPSM and persistent CK, respectively., Conclusions: Patients with thoracolumbar deformity without preoperative CD are likely to have greater improvements in HRQOL after surgery than patients with concomitant preoperative CD. Cervical positive sagittal alignment in adult patients with thoracolumbar deformity is strongly associated with inferior outcomes and failure to reach MCID at 2-year follow-up despite having similar baseline HRQOL to patients without CD. This was the first study to assess the impact of concomitant preoperative cervical malalignment in adult patients with thoracolumbar deformity. These results can help surgeons educate patients at risk for inferior outcomes and direct future research to identify an etiology and improve patient outcomes. Investigation into the etiology of the baseline cervical malalignment may be warranted in patients who present with thoracolumbar deformity.

Object: Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures., Methods: Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group., Results: One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29°, p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78°, p < 0.01), TL/L Cobb angle (MD: -16.24°, p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87°, p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24° vs 14.1°, p < 0.01), MT Cobb angle (53.5° vs 20.5°, p < 0.01), and TL/L Cobb angle (41.6° vs 16.6°, p < 0.01). Postoperative TL/L Cobb angle (23.1° vs 16.6°, p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent., Conclusions: Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.