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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.

Background and Objectives: Achieving spinopelvic realignment during adult spinal deformity (ASD) surgery does not always produce ideal outcomes. Little is known whether compensation in lower extremities (LEs) plays a role in this disassociation. The objective is to analyze lower extremity compensation after complex ASD surgery, its effect on outcomes, and whether correction can alleviate these mechanisms., Methods: We included patients with complex ASD with 6-week data. LE parameters were as follows: sacrofemoral angle, knee flexion angle, and ankle flexion angle. Each parameter was ranked, and upper tertile was deemed compensation. Patients compensating and not compensating postoperatively were propensity score matched for body mass index, frailty, and T1 pelvic angle. Linear regression assessed correlation between LE parameters and baseline deformity, demographics, and surgical details. Multivariate analysis controlling for baseline deformity and history of total knee/hip arthroplasty evaluated outcomes., Results: Two hundred and ten patients (age: 61.3 ± 14.1 years, body mass index: 27.4 ± 5.8 kg/m2, Charlson Comorbidity Index: 1.1 ± 1.6, 72% female, 22% previous total joint arthroplasty, 24% osteoporosis, levels fused: 13.1 ± 3.8) were included. At baseline, 59% were compensating in LE: 32% at hips, 39% knees, and 36% ankles. After correction, 61% were compensating at least one joint. Patients undercorrected postoperatively were less likely to relieve LE compensation (odds ratio: 0.2, P = .037). Patients compensating in LE were more often undercorrected in age-adjusted pelvic tilt, pelvic incidence, lumbar lordosis, and T1 pelvic angle and disproportioned in Global Alignment and Proportion (P < .05). Patients matched in sagittal age-adjusted score at 6 weeks but compensating in LE were more likely to develop proximal junctional kyphosis (odds ratio: 4.1, P = .009) and proximal junctional failure (8% vs 0%, P = .035) than those sagittal age-adjusted score-matched and not compensating in LE., Conclusion: Perioperative lower extremity compensation was a product of undercorrecting complex ASD. Even in age-adjusted realignment, compensation was associated with global undercorrection and junctional failure. Consideration of lower extremities during planning is vital to avoid adverse outcomes in perioperative course after complex ASD surgery., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Objective: Proximal junctional failure following surgical correction for adult spinal deformity significantly impacts quality of life and increases the economic burden of treating underlying spinal deformity. The objective of this cadaver study was to determine optimal tension parameters in junctional tethers for proximal junctional kyphosis prevention., Methods: Cadaveric specimens were used to establish the optimal tension range in polyethylene tethering devices, such as the VersaTie (NuVasive) used in this study. Three specimens were instrumented to test tether tensions of 0, 75, and 150 Newtons (N) at L1-L2, T9-T10, and T3-T4. An optical tracking system was used to measure when specimens reached proximal junctional kyphosis, experienced instrumentation or tissue failure, or reached a cap of 2500 cycles. Radiographs were obtained before and after testing., Results: At all levels, use of a tether at tension forces of 75 N and 150 N elicited a protective effect. The only level in which a higher tension on the tether resulted in more protection was at T3-T4. When averaged, the use of a tether at tension forces of 75 N and 150 N showed 1000 cycles of protection at L1-L2, 2000 cycles at T9-T10, and 1426 cycles at T3-T4. Radiographic analysis corroborated these findings., Conclusions: The use of a tether in a cadaveric model prevents the development of proximal junctional kyphosis across all tested levels and an increased tension force of 150 N is protective at the proximal thoracic spine. These data can be used to develop further models for a tether system that reproducibly applies a fixed tension force above the thoracolumbar rod construct., (Copyright © 2023. Published by Elsevier Inc.)

Background: Postoperative reciprocal changes (RC) in the cervical spine associated with varying factors of proximal junctional kyphosis (PJK) following fusions of the thoracopelvic spine are poorly understood., Purpose: Explore reciprocal changes in the cervical spine associated with varying factors (severity, progression, patient age) of PJK in patients undergoing adult spinal deformity (ASD) correction., Patients and Methods: Retrospective review of a multicenter ASD database., Inclusion: ASD patients > 18 y/o, undergoing fusions from the thoracic spine (UIV: T6-T12) to the pelvis with two-year radiographic data. ASD was defined as: Coronal Cobb angle ≥ 20°, Sagittal Vertical Axis ≥ 5 cm, Pelvic Tilt ≥ 25°, and/or Thoracic Kyphosis ≥ 60°. PJK was defined as a ≥ 10° measure of the sagittal Cobb angle between the inferior endplate of the UIV and the superior endplate of the UIV + 2. Patients were grouped by mild (M; 10°-20°) and severe (S; > 20°) PJK at one year. Propensity Score Matching (PSM) controlled for CCI, age, PI and UIV. Unpaired and paired t test analyses determined difference between RC parameters and change between time points. Pearson bi-variate correlations analyzed associations between RC parameters (T4-T12, TS-CL, cSVA, C2-Slope, and T1-Slope) and PJK descriptors., Results: 284 ASD patients (UIV: T6: 1.1%; T7: 0.7%; T8: 4.6%; T9: 9.9%; T10: 58.8%; T11: 19.4%; T12: 5.6%) were studied. PJK analysis consisted of 182 patients (Mild = 91 and Severe = 91). Significant difference between M and S groups were observed in T4-T12 Δ1Y(- 16.8 v - 22.8, P = 0.001), TS-CLΔ1Y(- 0.6 v 2.8, P = 0.037), cSVAΔ1Y(- 1.8 v 1.9, P = 0.032), and C2 slopeΔ1Y(- 1.6 v 2.3, P = 0.022). By two years post-op, all changes in cervical alignment parameters were similar between mild and severe groups. Correlation between age and cSVAΔ1Y(R = 0.153, P = 0.034) was found. Incidence of severe PJK was found to correlate with TS-CLΔ1Y(R = 0.142, P = 0.049), cSVAΔ1Y(R = 0.171, P = 0.018), C2SΔ1Y(R = 0.148, P = 0.040), and T1SΔ2Y(R = 0.256, P = 0.003)., Conclusions: Compensation within the cervical spine differed between individuals with mild and severe PJK at one year postoperatively. However, similar levels of pathologic change in cervical alignment parameters were seen by two years, highlighting the progression of cervical compensation due to mild PJK over time. These findings provide greater evidence for the development of cervical deformity in individuals presenting with proximal junctional kyphosis., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: To evaluate intraoperative monitoring (IOM) alerts and neurologic deficits during severe pediatric spinal deformity surgery., Methods: Patients with a minimum Cobb angle of 100° in any plane or a scheduled vertebral column resection (VCR) with minimum 2-year follow-up were prospectively evaluated (n = 243). Preoperative, immediate postoperative, and 2-year postoperative neurologic status were reported. Radiographic data included preoperative and 2-year postoperative coronal and sagittal Cobb angles and deformity angular ratios (DAR). IOM alert type and triggering event were recorded. SRS-22r scores were collected preoperatively and 2-years postoperatively., Results: IOM alerts occurred in 37% of procedures with three-column osteotomy (n = 36) and correction maneuver (n = 32) as most common triggering events. Patients with IOM alerts had greater maximum kyphosis (101.4° vs. 87.5°) and sagittal DAR (16.8 vs. 12.7) (p < 0.01). Multivariate regression demonstrated that sagittal DAR independently predicted IOM alerts (OR 1.05, 95% CI 1.02-1.08) with moderate sensitivity (60.2%) and specificity (64.8%) using a threshold value of 14.3 (p < 0.01). IOM alerts occurred more frequently in procedures with new postoperative neurologic deficits (17/24), and alerts with both SSEP and TCeMEP signals were associated with new postoperative deficits (p < 0.01). Most patients with new deficits experienced resolution at 2 years (16/20) and had equivalent postoperative SRS-22r scores. However, patients with persistent deficits had worse SRS-22r total score (3.8 vs. 4.2), self-image subscore (3.5 vs. 4.1), and function subscore (3.8 vs. 4.3) (p ≤ 0.04)., Conclusion: Multimodal IOM alerts are associated with sagittal kyphosis, and predict postoperative neurologic deficits. Most patients with new deficits experience resolution of their symptoms and have equivalent 2-year outcomes., Level of Evidence: II., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: Retrospective cohort study., Objective: Understand the benefit of addressing malalignment in revision surgery for proximal junctional kyphosis (PJK)., Summary of Background Data: PJK is a common cause of revision surgery for adult spinal deformity patients. During a revision, surgeons may elect to perform a proximal extension of the fusion, or also correct the source of the lumbopelvic mismatch., Materials and Methods: Recurrent PJK following revision surgery was the primary outcome. Revision surgical strategy was the primary predictor (proximal extension of fusion alone compared with combined sagittal correction and proximal extension). Multivariable logistic regression determined rates of recurrent PJK between the two surgical groups with lumbopelvic surgical correction assessed through improving ideal alignment in one or more alignment criteria [Global Alignment and Proportionality (GAP), Roussouly-type, and Sagittal Age-Adjusted Score (SAAS)]., Results: A total of 151 patients underwent revision surgery for PJK. PJK occurred at a rate of 43.0%, and PJF at 12.6%. Patients proportioned in GAP postrevision had lower rates of recurrent PJK [23% vs. 42%; odds ratio (OR): 0.3, 95% confidence interval (CI): 0.1-0.8, P =0.024]. Following adjusted analysis, patients who were ideally aligned in one of three criteria (Matching in SAAS and/or Roussouly matched and/or achieved GAP proportionality) had lower rates of recurrent PJK (36% vs. 53%; OR: 0.4, 95% CI: 0.1-0.9, P =0.035) and recurrent PJF (OR: 0.1, 95% CI: 0.02-0.7, P =0.015). Patients ideally aligned in two of three criteria avoid any development of PJF (0% vs. 16%, P <0.001)., Conclusions: Following revision surgery for PJK, patients with persistent poor sagittal alignment showed increased rates of recurrent PJK compared with patients who had abnormal lumbopelvic alignment corrected during the revision. These findings suggest addressing the root cause of surgical failure in addition to proximal extension of the fusion may be beneficial., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Pedicle subtraction osteotomy (PSO) is a surgical technique to restore lumbar lordosis in patients with rigid sagittal deformity. Herein, we report on outcomes of a surgical technique utilizing a 4-rod PSO with satellite rods., Methods: A retrospective study was performed for a cohort of patients who underwent 4-rod PSO revision surgery for sagittal deformity. Procedures were performed by one surgeon at 2 different academic centers between 2004-2018. Alignment outcomes and complications specifically for revision surgeries in previously fused spines were assessed., Results: 40 patients underwent PSO with the satellite rod technique (n = 29 at L3, 72.5%; n = 7 at L4, 17.5%). Mean PSO angle was 28.7 ± 7.6°. Two patients (5%) had rod fracture necessitating revision surgery at 32 and 34 months. Three patients (7.5%) developed proximal junctional kyphosis (PJK), but none required revision. No patients developed pseudoarthrosis. Mean preoperative sagittal vertical axis (SVA) was 13.5 ± 7.3 cm, which decreased to 4.8 ± 7.3 cm (P = 0.002) postoperatively. Mean preoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch improved from 35.9 ± 16.6° preoperatively to 11.8 ± 14.6° postoperatively (P < 0.001). Mean preoperative pelvic tilt (PT) improved from 34.7 ± 9.8° preoperatively to 30.1 ± 9.0° (P = 0.026) postoperatively. Mean global alignment and proportion (GAP) score improved from 10 ± 2 preoperatively to 8 ± 2 postoperatively (P < 0.001), which was still considered severely disproportioned., Conclusions: Rod failure rate after PSO with the 4-rod satellite configuration was low. SVA, PI-LL mismatch, and PT significantly improved for these previously-fused patients. Mean GAP score also improved, but was still considered severely disproportioned, likely due to the inability of PSO to correct low LL or PT in previously-fused spines., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Height gain following a surgical procedure for patients with adult spinal deformity (ASD) is incompletely understood, and it is unknown if height gain correlates with patient-reported outcome measures (PROMs)., Methods: This was a retrospective cohort study of patients undergoing ASD surgery. Patients with baseline, 6-week, and subanalysis of 1-year postoperative full-body radiographic and PROM data were examined. Correlation analysis examined relationships between vertical height differences and PROMs. Regression analysis was utilized to preoperatively estimate T1-S1 and S1-ankle height changes., Results: This study included 198 patients (mean age, 57 years; 69% female); 147 patients (74%) gained height. Patients with height loss, compared with those who gained height, experienced greater increases in thoracolumbar kyphosis (2.81° compared with -7.37°; p < 0.001) and thoracic kyphosis (12.96° compared with 4.42°; p = 0.003). For patients with height gain, sagittal and coronal alignment improved from baseline to postoperatively: 25° to 21° for pelvic tilt (PT), 14° to 3° for pelvic incidence - lumbar lordosis (PI-LL), and 60 mm to 17 mm for sagittal vertical axis (SVA) (all p < 0.001). The full-body mean height gain was 7.6 cm, distributed as follows: sella turcica-C2, 2.9 mm; C2-T1, 2.8 mm; T1-S1 (trunk gain), 3.8 cm; and S1-ankle (lower-extremity gain), 3.3 cm (p < 0.001). T1-S1 height gain correlated with the thoracic Cobb angle correction and the maximum Cobb angle correction (p = 0.002). S1-ankle height gain correlated with the corrections in PT, PI-LL, and SVA (p < 0.001). T1-ankle height gain correlated with the corrections in PT (p < 0.001) and SVA (p = 0.03). Trunk height gain correlated with improved Scoliosis Research Society (SRS-22r) Appearance scores (r = 0.20; p = 0.02). Patient-Reported Outcomes Measurement Information System (PROMIS) Depression scores correlated with S1-ankle height gain (r = -0.19; p = 0.03) and C2-T1 height gain (r = -0.18; p = 0.04). A 1° correction in a thoracic scoliosis Cobb angle corresponded to a 0.2-mm height gain, and a 1° correction in a thoracolumbar scoliosis Cobb angle resulted in a 0.25-mm height gain. A 1° improvement in PI-LL resulted in a 0.2-mm height gain., Conclusions: Most patients undergoing ASD surgery experienced height gain following deformity correction, with a mean full-body height gain of 7.6 cm. Height gain can be estimated preoperatively with predictive ratios, and height gain was correlated with improvements in reported SRS-22r appearance and PROMIS scores., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H620 )., (Copyright © 2023 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

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: The objective of this study was to explore the rate of proximal junctional failure (PJF) and functional outcomes of normative alignment goals compared with alignment targets based on age-appropriate physical function., Methods: Baseline relationships between age, pelvic incidence (PI), and a component of the T1 pelvic angle (TPA) within the fusion were analyzed in adult spinal deformity (ASD) patients and compared with those of asymptomatic patients. Linear regression modeling was used to determine alignment based on PI and age in asymptomatic patients (normative alignment), and in ASD patients, alignment corresponding to age-appropriate functional status (functional alignment). A cohort of 288 ASD patients was split into two groups based on whether the patient was closer to their normative or functional alignment goal at their 6-week postoperative radiographic follow-up. The rates of proximal junctional kyphosis (PJK) and PJF were determined for each cohort., Results: In the 288 ASD patients included in this pre- to postoperative analysis, there was no difference in baseline alignment or health-related quality of life (HRQOL) between the normative alignment and functional alignment groups. At 6 weeks, patients with normative alignment had a smaller TPA (4.45° vs 14.1°) and PI minus lumbar lordosis (-7.24° vs 7.4°) (both p < 0.0001) and higher PJK (40% vs 27.2%, p = 0.03) and PJF (17% vs 6.8%, p = 0.008) rates than patients with functional alignment., Conclusions: Correction in ASD patients to normative alignment resulted in higher rates of PJK and PJF without improvements in HRQOL. Correction in ASD patients to functional alignment that mirrors the physical function of their age-matched asymptomatic peers is recommended.

Study Design: Retrospective review of prospectively collected data., Objective: To determine the incidence of medical complications in the pediatric population aged 10-20 years with baseline deformities exceeding 100 degrees or who had 3CO at surgery. Severe pediatric spine deformity poses a great challenge to the treating physician and carries a high complication rate. Pulmonary complications are among the most life threatening. The onus is on the treating surgeon to identify patients who are high risk and institute measures to mitigate the risk for successful outcomes., Method: Data of 251/311pts from FOX pediatric database from 17 international sites was queried for incidence of major medical complications. Comparative analysis was done to determine the impact of such complications on HRQoL using paired t-test. Risk factors associated with medical complications were assessed using Firth logistic regression., Results: 251/311pts had min 2 year f/u. 142F/109 M, average age 14.61years (10-20). Etiologies included 96 Cong,94 Idiopathic, 14-Post TB, 12-NM,12-NF,10-syndromic,8 others. Curve types included Scoliosis-121, Kyphoscoliosis 72, Kyphosis 58. Coronal and sag cobb avg 88° ± 41.47 and 91.92° ± 39.17, respectively. Deformity apices were in the thoracic region in 88% of patients. Pre-op co-morbidities included 54 (21.5%) cardiopulmonary; 7(2.79%) Genitounrinary;13 (5.18%) GI;13 (5.18%) Anxiety/depression; neurological 24 (9.56%). HGT was utilized in 103pts (41%) at an average duration of 68 days. Mean OR time was 459 min, blood loss averaged 1465 ml. VCR was performed in 120(47.81%), PSO in 16 pts (6.37%), SPO in 145pts (57.77%), Thoracoplasty in 132 pts (52.8%). 96% had blood and other blood products transfusion (FFP and platelets). There were 35 post-op medical complications occurring in 29pts (11.6%). Event-specific cumulative incidence was 24 (9.6%) pulmonary, 5(2.0%) gastrointestinal, 3(1.2%) cardiovascular, 1(0.4%) genitourinary and 1(0.4%) other complication. There was no mortality. Osteotomy grade was found to be an independent predictor of pulmonary complication. Despite significant improvement in baseline SRS total and Domain scores at 2 year FU irrespective of medical complication, the improvement in SRS scores were blunted in the complication group., Conclusion: Medical complications are common among pediatric patients undergoing complex spine surgery for severe deformity. However, medical complications can be managed successfully. Although baseline HRQoL improved irrespective of medical complication status, clinical differences in the magnitude of the changes in HRQoL were observed in some domains., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

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 objective of this paper was to report mechanical complications and patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) patients with a Roussouly "false type 2" (FT2) profile., Methods: ASD patients treated from 2004 to 2014 at a single center were identified. Inclusion criteria were pelvic incidence ≥ 60° and a minimum 2-year follow-up. FT2 was defined as a high postoperative pelvic tilt (PT), as defined by the Global Alignment and Proportion target, and thoracic kyphosis < 30°. Mechanical complications, defined as proximal junctional kyphosis (PJK) and/or instrumentation failure, were determined and compared. Scoliosis Research Society-22r (SRS-22r) scores were compared between groups., Results: Ninety-five patients (normal PT [NPT] group 49, FT2 group 46) who met the inclusion criteria were identified and studied. Most surgeries were revisions (NPT group 30 [61%], FT2 group 30 [65%]), and most were performed via a posterior-only approach (86%) (mean ± SD 9.6 ± 5 levels). Proximal junctional angles increased after surgery in both groups, without differences between groups. Neither rates of radiographic PJK (p = 0.10), revision for PJK (p = 0.45), nor revision for pseudarthrosis (p = 0.66) were different between groups. There were no differences between groups for SRS-22r domain scores or subscores., Conclusions: In this single-center experience, patients with high pelvic incidence fixed with persistent lumbopelvic parameter mismatch and engaged compensatory mechanisms (Roussouly FT2) had mechanical complications and PROMs not different from those with normalized alignment parameters. Compensatory PT may be acceptable in some cases of ASD surgery.

Purpose: To evaluate the impact of the lowest instrumented vertebra (LIV) on Distal Junctional kyphosis (DJK) incidence in adult cervical deformity (ACD) surgery., Methods: Prospectively collected data from ACD patients undergoing posterior or anterior-posterior reconstruction at 13 US sites was reviewed up to 2-years postoperatively (n = 140). Data was stratified into five groups by level of LIV: C6-C7, T1-T2, T3-Apex, Apex-T10, and T11-L2. DJK was defined as a kyphotic increase > 10° in Cobb angle from LIV to LIV-1. Analysis included DJK-free survival, covariate-controlled cox regression, and DJK incidence at 1-year follow-up., Results: 25/27 cases of DJK developed within 1-year post-op. In patients with a minimum follow-up of 1-year (n = 102), the incidence of DJK by level of LIV was: C6-7 (3/12, 25.00%), T1-T2 (3/29, 10.34%), T3-Apex (7/41, 17.07%), Apex-T10 (8/11, 72.73%), and T11-L2 (4/8, 50.00%) (p < 0.001). DJK incidence was significantly lower in the T1-T2 LIV group (adjusted residual = -2.13), and significantly higher in the Apex-T10 LIV group (adjusted residual = 3.91). In covariate-controlled regression using the T11-L2 LIV group as reference, LIV selected at the T1-T2 level (HR = 0.054, p = 0.008) or T3-Apex level (HR = 0.081, p = 0.010) was associated with significantly lower risk of DJK. However, there was no difference in DJK risk when LIV was selected at the C6-C7 level (HR = 0.239, p = 0.214)., Conclusion: DJK risk is lower when the LIV is at the upper thoracic segment than the lower cervical segment. DJK incidence is highest with LIV level in the lower thoracic or thoracolumbar junction., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Despite adequate correction, the pelvis may fail to readjust, deemed pelvic nonresponse (PNR). To assess alignment outcomes [PNR, proximal junctional kyphosis (PJK), postoperative cervical deformity (CD)] following adult spinal deformity (ASD) surgery utilizing different realignment strategies., Materials and Methods: ASD patients with two-year data were included. PNR defined as undercorrected in age-adjusted pelvic tilt (PT) at six weeks and maintained at two years. Patients classified by alignment utilities: (a) improvement in Scoliosis Research Society-Schwab sagittal vertical axis, (b) matching in age-adjusted pelvic incidence-lumbar lordosis, (c) matching in Roussouly, (d) aligning Global Alignment and Proportionality (GAP) score. Multivariable regression analyses, controlling for age, baseline deformity, and surgical factors, assessed rates of PNR, PJK, and CD development following realignment., Results: A total of 686 patients met the inclusion criteria. Rates of postoperative PJK and CD were not significant in the PNR group (both P >0.15). PNR patients less often met substantial clinical benefit in Oswestry Disability Index by two years [odds ratio: 0.6 (0.4-0.98)]. Patients overcorrected in age-adjusted pelvic incidence-lumbar lordosis, matching Roussouly, or proportioned in GAP at six weeks had lower rates of PNR (all P <0.001). Incremental addition of classifications led to 0% occurrence of PNR, PJK, and CD. Stratifying by baseline PT severity, Low and moderate deformity demonstrated the least incidence of PNR (7.7%) when proportioning in GAP at six weeks, while severe PT benefited most from matching in Roussouly (all P <0.05)., Conclusions: Following ASD corrective surgery, 24.9% of patients showed residual pelvic malalignment. This occurrence was often accompanied by undercorrection of lumbopelvic mismatch and less improvement of pain. However, overcorrection in any strategy incurred higher rates of PJK. We recommend surgeons identify a middle ground using one, or more, of the available classifications to inform correction goals in this regard., Level of Evidence: III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Diagnostic binary threshold analysis., Objective: (1) Perform a sensitivity analysis demonstrating the test performance metrics for any combination of proximal junctional angle (PJA) magnitude and change; (2) Propose a new proximal junctional kyphosis (PJK) criteria., Summary of Background Data: Previous definitions of PJK have been arbitrarily selected and then tested through retrospective case series, often showing little correlation with clinical outcomes., Materials and Methods: Surgically treated adult spinal deformity patients (≥4 levels fused) enrolled into a prospective, multicenter database were evaluated at a minimum 2-year follow-up for proximal junctional failure (PJF). Using PJF as the outcome of interest, test performance metrics including sensitivity, positive predictive value, and F1 metrics (harmonic mean of precision and recall) were calculated for all combinations of PJA magnitude and change using different combinations of perijunctional vertebrae. The combination with the highest F1 score was selected as the new PJK criteria. Performance metrics of previous PJK definitions and the new PJK definition were compared., Results: Of the total, 669 patients were reviewed. PJF rate was 10%. Overall, the highest F1 scores were achieved when the upper instrumented vertebrae -1 (UIV-1)/UIV+2 angle was measured. For lower thoracic cases, out of all the PJA and magnitude/change combinations tested, a UIV-1/UIV+2 magnitude of -28° and a change of -20° was associated with the highest F1 score. For upper thoracic cases, a UIV-1/UIV+2 magnitude of -30° and a change of -24° were associated with the highest F1 score. Using PJF as the outcome, patients meeting this new criterion (11.5%) at 6 weeks had the lowest survival rate (74.7%) at 2 years postoperative, compared with Glattes (84.4%) and Bridwell (77.4%)., Conclusions: Out of all possible PJA magnitude and change combinations, without stratifying by upper thoracic versus lower thoracic fusions, a magnitude of ≤-28° and a change of ≤-22° provide the best test performance metrics for predicting PJF., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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: Proximal junctional failure (PJF) is a severe form of proximal junctional kyphosis. Previous reports on PJF have been limited by heterogeneous cohorts and relatively short follow-ups. The authors' objectives herein were to identify risk factors for PJF and to assess its long-term incidence and revision rates in a homogeneous cohort., Methods: The authors reviewed data from the Adult Symptomatic Lumbar Scoliosis 1 trial (ASLS-1), a National Institutes of Health-sponsored prospective multicenter study. Inclusion criteria were an age ≥ 40 years, ASLS (Cobb angle ≥ 30° and Oswestry Disability Index [ODI] ≥ 20 or Scoliosis Research Society revised 22-item questionnaire [SRS-22r] score ≤ 4.0 in pain, function, or self-image domains), and primary thoracolumbar fusion/fixation to the sacrum/pelvis of ≥ 7 levels. PJF was defined as a postoperative proximal junctional angle (PJA) change > 20°, fracture of the uppermost instrumented vertebra (UIV) or UIV+1 with > 20% vertebral height loss, spondylolisthesis of UIV/UIV+1 > 3 mm, or UIV screw dislodgment., Results: One hundred sixty patients (141 women) were included in this analysis and had a median age of 62 years and a mean follow-up of 4.3 years (range 0.1-6.1 years). Forty-six patients (28.8%) had PJF at a median of 0.92 years (IQR 0.14, 1.23 years) following surgery. Based on Kaplan-Meier analyses, PJF rates at 1, 2, 3, and 4 years were 14.4%, 21.9%, 25.9%, and 27.4%, respectively. On univariate analysis, PJF was associated with greater age (p = 0.0316), greater body mass index (BMI; p = 0.0319), worse baseline patient-reported outcome measures (PROMs; ODI, SRS-22r, and SF-12 Physical Component Summary [PCS]; all p < 0.04), the use of posterior column osteotomies (PCOs; p = 0.0039), and greater postoperative thoracic kyphosis (TK; p = 0.0031) and PJA (p < 0.001). The use of UIV hooks was protective against PJF (p = 0.0340). On regression analysis (without postoperative measures), PJF was associated with greater BMI (HR 1.077, 95% CI 1.007-1.153, p = 0.0317), lower preoperative PJA (HR 0.607, 95% CI 0.407-0.906, p = 0.0146), and greater preoperative TK (HR 1.362, 95% CI 1.082-1.715, p = 0.0085). Patients with PJF had worse PROMs at the last follow-up (ODI, SRS-22r subscore and self-image, and SF-12 PCS; p < 0.04). Sixteen PJF patients (34.8%) underwent revision, and PJF recurred in 3 (18.8%)., Conclusions: Among 160 primary ASLS patients with a median age of 62 years and predominant coronal deformity, the PJF rate was 28.8% at a mean 4.3-year follow-up, with a revision rate of 34.8%. On univariate analysis, PJF was associated with a greater age and BMI, worse baseline PROMs, the use of PCOs, and greater postoperative TK and PJA. The use of UIV hooks was protective against PJF. On multivariate analysis (without postoperative measures), a higher risk of PJF was associated with greater BMI and preoperative TK and lower preoperative PJA.

Summary of Background Data: The influence of frailty on economic burden following corrective surgery for the adult cervical deformity (CD) is understudied and may provide valuable insights for preoperative planning., Objective: To assess the influence of baseline frailty status on the economic burden of CD surgery., Study Design: Retrospective cohort., Materials and Methods: CD patients with frailty scores and baseline and two-year Neck Disability Index data were included. Frailty score was categorized patients by modified CD frailty index into not frail (NF) and frail (F). Analysis of covariance was used to estimate marginal means adjusting for age, sex, surgical approach, and baseline sacral slope, T1 slope minus cervical lordosis, C2-C7 angle, C2-C7 sagittal vertical axis. Costs were derived from PearlDiver registry data. Reimbursement consisted of a standardized estimate using regression analysis of Medicare payscales for services within a 30-day window including length of stay and death. This data is representative of the national average Medicare cost differentiated by complication/comorbidity outcome, surgical approach, and revision status. Cost per quality-adjusted life-year (QALY) at two years was calculated for NF and F patients., Results: There were 126 patients included. There were 68 NF patients and 58 classified as F. Frailty groups did not differ by overall complications, instance of distal junctional kyphosis, or reoperations (all P >0.05). These groups had similar rates of radiographic and clinical improvement by two years. NF and F had similar overall cost ($36,731.03 vs. $37,356.75, P =0.793), resulting in equivocal costs per QALYs for both patients at two years ($90,113.79 vs. $80,866.66, P =0.097)., Conclusion: F and NF patients experienced similar complication rates and upfront costs, with equivocal utility gained, leading to comparative cost-effectiveness with NF patients based on cost per QALYs at two years. Surgical correction for CD is an economical healthcare investment for F patients when accounting for anticipated utility gained and cost-effectiveness following the procedure., Level of Evidence: III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective study of a multicenter Adult Spinal Deformity (ASD) Database., Objective: To investigate the change in Pelvic tilt (PT) imparted by regional changes in lumbar lordosis at 2-year minimum follow up., Summary of Background Data: The distribution of lumbar lordosis between L1-4 and L4-S1 is known to vary based on pelvic incidence (PI). However, the extent to which regional changes effect PT is not clearly elucidated. This information can be useful for ASD surgical planning., Methods: Operative patients from a multicenter ASD database were included with Lowest Instrumented Vertebrae (LIV) S1/Ilium, >5 levels of fusion, Proximal Junction Kyphosis (PJK) angle < 20, and >5 degrees of change in lumbar lordosis from L4-S1 and L1-4. Radiographic analysis was performed evaluating Thoracic Kyphosis (TK), T10-L2 kyphosis (TL), L1-S1 lordosis (LL), L4-S1 lordosis, L1-4 lordosis, sagittal vertical axis (SVA) and PI-LL from preoperative to postoperative, and change at 2-years follow-up. Stepwise regression analysis was performed in order to determine the relationship between PT and the above radiographic parameters. Health-related quality of life (HRQOL) outcomes were also compared between preoperative and postoperative timepoints at 2 years., Results: 103 patients met inclusion for the study. There was improvement in all the radiographic parameters and HRQOLs at 2 years follow-up (p < 0.01). Stepwise regression model showed an inverse relationship between PT and LL change (r = 0.71, p < 0.01). Regionally, an increase in 10 degrees from L4-S1 correlated with a 2.4 degree decrease in PT (p < 0.01), while an increase in 10 degrees from L1-4 resulted in a 1.6 degree decrease in PT (p < 0.01)., Conclusion: In the surgical planning for ASD, our data demonstrated significant correlational difference between corrections in the upper (L1-4) and lower (L4-S1) lumbar spine and PT changes. These calculations can be useful in planning sagittal plane corrections for ASD., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Adult cervical deformity (ACD) has high complication rates due to surgical complexity and patient frailty. Very few studies have focused on longer-term outcomes of operative ACD treatment. The objective of this study was to assess minimum 2-year outcomes and complications of ACD surgery., Methods: A multicenter, prospective observational study was performed at 13 centers across the United States to evaluate surgical outcomes for ACD. Demographics, complications, radiographic parameters, and patient-reported outcome measures (PROMs; Neck Disability Index, modified Japanese Orthopaedic Association, EuroQol-5D [EQ-5D], and numeric rating scale [NRS] for neck and back pain) were evaluated, and analyses focused on patients with ≥ 2-year follow-up., Results: Of 169 patients with ACD who were eligible for the study, 102 (60.4%) had a minimum 2-year follow-up (mean 3.4 years, range 2-8.1 years). The mean age at surgery was 62 years (SD 11 years). Surgical approaches included anterior-only (22.8%), posterior-only (39.6%), and combined (37.6%). PROMs significantly improved from baseline to last follow-up, including Neck Disability Index (from 47.3 to 33.0) and modified Japanese Orthopaedic Association score (from 12.0 to 12.8; for patients with baseline score ≤ 14), neck pain NRS (from 6.8 to 3.8), back pain NRS (from 5.5 to 4.8), EQ-5D score (from 0.74 to 0.78), and EQ-5D visual analog scale score (from 59.5 to 66.6) (all p ≤ 0.04). More than half of the patients (n = 58, 56.9%) had at least one complication, with the most common complications including dysphagia, distal junctional kyphosis, instrumentation failure, and cardiopulmonary events. The patients who did not achieve 2-year follow-up (n = 67) were similar to study patients based on baseline demographics, comorbidities, and PROMs. Over the course of follow-up, 23 of the total 169 enrolled patients were reported to have died. Notably, these represent all-cause mortalities during the course of follow-up., Conclusions: This multicenter, prospective analysis demonstrates that operative treatment for ACD provides significant improvement of health-related quality of life at a mean 3.4-year follow-up, despite high complication rates and a high rate of all-cause mortality that is reflective of the overall frailty of this patient population. To the authors' knowledge, this study represents the largest and most comprehensive prospective effort to date designed to assess the intermediate-term outcomes and complications of operative treatment for ACD.

Study Design: Retrospective cohort study., Objective: The aim of this study was to investigate the evolution of proximal junctional kyphosis (PJK) rate over 10-year enrollment period within a prospective database., Summary of Background Data: PJK is a common complication following adult spinal deformity (ASD) surgery and has been intensively studied over the last decade., Methods: Patients with instrumentation extended to the pelvis and minimum 2-year follow-up were included. To investigate evolution of PJK/proximal junctional failure (PJF) rate, a moving average of 321 patients was calculated across the enrollment period. Logistic regression was used to investigate the association between the date of surgery (DOS) and PJK and/or PJF. Comparison of PJK/PJF rates, demographics, and surgical strategies was performed between the first and second half of the cohort., Results: A total of 641 patients met inclusion criteria (age: 64±10 years, 78.2% female, body mass index: 28.3±5.7). The overall rate of radiographic PJK at 2 years was 47.9%; 12.9% of the patients developed PJF, with 31.3% being revised within 2-year follow-up. Stratification by DOS produced two halves. Between these two periods, rate of PJK and PJF demonstrated nonsignificant decrease (50.3%-45.5%, P =0.22) and (15.0%-10.9%, P =0.12), respectively. Linear interpolation suggested a decrease of 1.2% PJK per year and 1.0% for PJF. Patients enrolled later in the study were older and more likely to be classified as pure sagittal deformity ( P <0.001). There was a significant reduction in the use of three-column osteotomies ( P <0.001), an increase in anterior longitudinal ligament release ( P <0.001), and an increase in the use of PJK prophylaxis (31.3% vs 55.1%). Logistical regression demonstrated no significant association between DOS and radiographic PJK ( P =0.19) or PJF ( P =0.39)., Conclusion: Despite extensive research examining risk factors for PJK/PJF and increasing utilization of intraoperative PJK prophylaxis techniques, the rate of radiographic PJK and/or PJF did not significantly decrease across the 10-year enrollment period of this ASD database., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: This was a retrospective review of a prospectively collected database., Objective: The aim of this study was to delineate radiographic parameters that distinguish severe cervical spine deformity (CSD)., Summary of Background Data: Our objective was to define parameters that distinguish severe CSD using a consensus approach combined with discriminant analysis as no system currently exists in the literature., Methods: Twelve CSD surgeons reviewed preoperative x-rays from a CSD database. A consensus was reached for categorizing patients into a severe cervical deformity (sCD), non-severe cervical deformity (non-sCD), or an indeterminate cohort. Radiographic parameters were found including classic cervical and spinopelvic parameters in neutral/flexion/extension alignment. To perform our discriminant analysis, we selected for parameters that had a significant difference between the sCD and non-sCD groups using the Student t test. A discriminant function analysis was used to determine which variables discriminate between the sCD versus non-sCD. A stepwise analysis was performed to build a model of parameters to delineate sCD., Results: A total of 146 patients with cervical deformity were reviewed (60.5±10.5 y; body mass index: 29.8 kg/m2; 61.3% female). There were 83 (56.8%) classified as sCD and 51 (34.9%) as non-sCD. The comparison analysis led to 16 radiographic parameters that were different between cohorts, and 5 parameters discriminated sCD and non-sCD. These parameters were cervical sagittal vertical axis, T1 slope, maximum focal kyphosis in extension, C2 slope in extension, and number of kyphotic levels in extension. The canonical coefficient of correlation was 0.689, demonstrating a strong association between our model and cervical deformity classification. The accuracy of classification was 87.0%, and cross-validation was 85.2% successful., Conclusions: More than one third of a series of CSD patients were not considered to have a sCD. Analysis of an initial 17 parameters showed that a subset of 5 parameters can discriminate between sCD versus non-sCD with 85% accuracy. Our study demonstrates that flexion/extension images are critical for defining severe CD., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort study., Objective: Determine whether screws per level and rod material/diameter are associated with incidence of proximal junctional kyphosis (PJF)., Summary of Background Data: PJF is a common and particularly adverse complication of adult spinal deformity (ASD) surgery. There is evidence that the rigidity of posterior spinal constructs may impact risk of PJF., Methods: Patients with ASD and 2-year minimum follow-up were included. Only patients undergoing primary fusion of more than or equal to five levels with lower instrumented vertebrae (LIV) at the sacro-pelvis were included. Screws per level fused was analyzed with a cutoff of 1.8 (determined by receiver operating characteristic curve (ROC) analysis). Multivariable logistic regression was utilized, controlling for age, body mass index (BMI), 6-week postoperative change from baseline in lumbar lordosis, number of posterior levels fused, sex, Charlson comorbidity index, approach, osteotomy, upper instrumented vertebra (UIV), osteoporosis, preoperative TPA, and pedicle screw at the UIV (as opposed to hook, wire, etc.)., Results: In total, 504 patients were included. PJF occurred in 12.7%. The mean screws per level was 1.7, and 56.8% of patients had less than 1.8 screws per level. No differences were observed between low versus high screw density groups for T1-pelvic angle or magnitude of lordosis correction (both P > 0.15). PJF occurred in 17.0% versus 9.4% of patients with more than or equal to 1.8 versus less than 1.8 screws per level, respectively (P < 0.05). In multivariable analysis, patients with less than 1.8 screws per level exhibited lower odds of PJF (odds ratio (OR) 0.48, P < 0.05), and a continuous variable for screw density was significantly associated with PJF (OR 3.87 per 0.5 screws per level, P < 0.05). Rod material and diameter were not significantly associated with PJF (both P > 0.1)., Conclusion: Among ASD patients undergoing long-segment primary fusion to the pelvis, the risk of PJF was lower among patients with less than 1.8 screws per level. This finding may be related to construct rigidity. Residual confounding by other patient and surgeon-specific characteristics may exist. Further biomechanical and clinical studies exploring this relationship are warranted.Level of Evidence: 3., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

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: 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.

Study Design: Prospective multicenter international observational study., Objective: To investigate incidence of new neurologic deficit (NND) and the long-term recovery patterns following complex pediatric spine deformity surgery. The SRS M&M reports identify pediatric patients as having higher rate of new neurologic deficit compared with adults, while congenital and neuromuscular deformities are associated with higher new neurologic risks. Very few studies have had the large numbers of pediatric patients with curves exceeding 100 deg to ascertain the new neurologic deficit (NND) rates and recovery patterns as it relates to curve laterality and diagnosis., Method: The FOX pediatric database from 17 international sites was queried for New Neurologic Deficit (NND) as characterized by change in American Spinal Injury Association (ASIA) Lower or Upper Extremity Motor Score. Recovery rates at specific intervals were recorded and related to the curve type and etiology., Results: Data of 286 consecutive patients with normal pre-operative neurologic exams were reviewed. There were 160 females vs 125 males with an average age of 14.6 years. NND occurred in 27 patients (9.4%) in the immediate post-operative period. Diagnostic categories included idiopathic scoliosis (3 patients); idiopathic kyphoscoliosis(5 patients); congenital scoliosis (7 patients); congenital kyphoscoliosis (4 patients); congenital kyphosis (6 patients), other kyphosis (1 patient) and syndromic (1 patient). 1 patient was lost to follow-up (f/u) after discharge; 1 had chronic deficits at the first post-operative erect visit (from discharge to 9 months f/u) and was subsequently lost to follow-up; 2 patients were improving at 1-year f/u but lost to subsequent f/u. 16 patients had normal neurologic function by the time of the first post-operative erect visit, 21 patients at 1-year f/u and 21 patients at the 2-year f/u. 2 patients (0.69%) had improved NND at 2-year mark., Conclusion: A significant proportion of patients with complex spine deformity experience NND. However, significant improvement in neurologic function can be expected over time as seen in this study without additional surgical intervention in most cases. Congenital deformities accounted for 63% of the patients experiencing NND.

Background: Novel radiographic sagittal parameters of the thoracolumbar junction orientation (TLJO, thoracolumbar slope [TLS] and thoracolumbar tilt [TLT]) have been introduced and correlated with lumbopelvic parameters and thoracic kyphosis., Objective: To determine a predictive model for reciprocal thoracic kyphosis and proximal junctional kyphosis (PJK) based on the TLJO., Methods: A total of 127 patients who had fusion from sacrum to T10-L2 from 2004 to 2014 were reviewed. TK (T5-T12), PI, SS, PT, LL, and proximal junctional angle (PJA) were measured preoperatively, 6 wk postoperatively, and at final follow-up. TLJO was measured by TLS and TLT. Changes between time points were determined (preop-6 wk = ΔParameterPre6wk and preop-final follow/up = ΔParameterPreFinal). Scoliosis Research Society (SRS) and Oswestry Disability Index (ODI) questionnaires were evaluated at final follow-up. Patients were divided into 2 groups based on the presence of PJK (ΔPJAPreFinal >15°). Independent t-tests and receiver operating characteristic (ROC) curves were used to investigate the significance of differences and cut-off values. Pearson correlations and linear regressions were used to analyze the entire cohort to determine the relationship between the changes in parameters., Results: Compared to patients without PJK (n = 100), those with PJK (n = 27) had significantly lower SRS scores and significantly greater ΔTKPreFinal, ΔLLPre6wk, and ΔTLSPre6wk. To maintain in the nonPJK group, ROC curves demonstrated a cut-off value of -9.4° for ΔTLSPre6wk. PJK was significantly correlated with ΔTKPreFinal and ΔTLSPre6wk. The linear correlation revealed that ΔTLSPre6wk < -25.3° is the risk factor of PJK > 15°., Conclusion: As change of TLS reflects lumbopelvic realignment and influences reciprocal TK, reducing the change of TLS may be a sagittal realignment guideline to reduce the risk of PJK., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Study Design: Propensity score matched analysis of a multi-center prospective adult spinal deformity (ASD) database., Objective: Evaluate if surgical implant prophylaxis combined with avoidance of sagittal overcorrection more effectively prevents proximal junctional failure (PJF) than use of surgical implants alone., Summary of Background Data: PJF is a severe form of proximal junctional kyphosis (PJK). Efforts to prevent PJF have focused on use of surgical implants. Less information exists on avoidance of overcorrection of age-adjusted sagittal alignment to prevent PJF., Methods: Surgically treated ASD patients (age ≥18 yrs; ≥5 levels fused, ≥1 year follow-up) enrolled into a prospective multi-center ASD database were propensity score matched (PSM) to control for risk factors for PJF. Patients evaluated for use of surgical implants to prevent PJF (IMPLANT) versus no implant prophylaxis (NONE), and categorized by the type of implant used (CEMENT, HOOK, TETHER). Postoperative sagittal alignment was evaluated for overcorrection of age-adjusted sagittal alignment (OVER) versus within sagittal parameters (ALIGN). Incidence of PJF was evaluated at minimum 1 year postop., Results: Six hundred twenty five of 834 eligible for study inclusion were evaluated. Following PSM to control for confounding variables, analysis demonstrated the incidence of PJF was lower for IMPLANT (n = 235; 10.6%) versus NONE (n = 390: 20.3%; P < 0.05). Use of transverse process hooks at the upper instrumented vertebra (HOOK; n = 115) had the lowest rate of PJF (7.0%) versus NONE (20.3%; P < 0.05). ALIGN (n = 246) had lower incidence of PJF than OVER (n = 379; 12.0% vs. 19.2%, respectively; P < 0.05). The combination of ALIGN-IMPLANT further reduced PJF rates (n = 81; 9.9%), while OVER-NONE had the highest rate of PJF (n = 225; 24.2%; P < 0.05)., Conclusion: Propensity score matched analysis of 625 ASD patients demonstrated use of surgical implants alone to prevent PJF was less effective than combining implants with avoidance of sagittal overcorrection. Patients that received no PJF implant prophylaxis and had sagittal overcorrection had the highest incidence of PJF., Level of Evidence: 3.

Background: Despite advancements in surgical techniques, controversy remains regarding the optimal implant density for the correction of idiopathic scoliosis. Recent evidence has suggested that equivalent radiographic and clinical outcomes can be achieved with lower implant densities for those with moderate curves and good flexibility. Among the experts, the consensus has continued that higher implant densities should be used for larger, stiffer curves. The purpose of the present study was to compare the radiographic results between high-implant density (HID) and low-implant density (LID) constructs in patients with large (>65°), rigid (<50% flexibility) curves who had undergone anterior release and posterior spinal fusion., Methods: We reviewed the idiopathic scoliosis cases performed at a single institution from 2006 to 2014. Only those meeting the inclusion criteria were selected. The patients were divided into HID and LID groups. The postoperative radiographs were compared for coronal correction, thoracic kyphosis, pelvic tilt, lumbar lordosis, and sagittal vertical axis., Results: A statistically significant improvement in coronal correction was detected in the HID group at all follow-up points (final follow-up: HID, 81.1% vs. LID, 70.4%; P = 0.01). When preoperative thoracic kyphosis was considered, no differences were found between the 2 groups. No differences were found in the other sagittal parameters., Conclusion: In patients with large, rigid idiopathic scoliosis undergoing anterior release and posterior spinal fusion, a small, but statistically, significant improvement in the coronal Cobb angle was seen. It remains to be determined whether this small difference in radiographic correction will have any influence on the clinical outcome., (Published by Elsevier Inc.)

Background: Proximal junctional kyphosis (PJK) is a common radiographic complication of adult spinal deformity (ASD) corrective surgery. Although previous literature has reported a 5 to 61% incidence of PJK, these studies are limited by small sample sizes and short-term follow-up., Objective: To assess the incidence of PJK utilizing a high-powered ASD database., Methods: Retrospective review of a prospective multicenter ASD database. Operative ASD patients > 18 yr old from 2009 to 2017 were included. PJK was defined as ≥ 10° for the sagittal Cobb angle between the inferior upper instrumented vertebra (UIV) endplate and the superior endplate of the UIV + 2. Chi-square analysis and post hoc testing assessed annual and overall incidence of acute (6-wk follow-up [f/u]), progressive (increase in degree of PJK from 6 wk to 1 yr), and delayed (1-yr, 2-yr, and 3-yr f/u) PJK development., Results: A total of 1005 patients were included (age: 59.3; 73.5% F; body mass index: 27.99). Overall PJK incidence was 69.4%. Overall incidence of acute PJK was 48.0%. Annual incidence of acute PJK has decreased from 53.7% in 2012 to 31.6% in 2017 (P = .038). Overall incidence of progressive PJK was 35.0%, with stable rates observed from 2009 to 2016 (P = .297). Overall incidence of 1-yr-delayed PJK was 9.3%. Annual incidence of 1-yr-delayed PJK has decreased from 9.2% in 2009 to 3.2% in 2016 (P < .001). Overall incidence of 2-yr-delayed PJK development was 4.3%. Annual incidence of 2-yr-delayed PJK has decreased from 7.3% in 2009 to 0.9% in 2015 (P < .05). Overall incidence of 3-yr-delayed PJK was 1.8%, with stable rates observed from 2009 to 2014 (P = .594)., Conclusion: Although progressive PJK has remained a challenge for physicians over time, significantly lower incidences of acute and delayed PJK in recent years may indicate improving operative decision-making and management strategies., (Copyright © 2019 by the Congress of Neurological Surgeons.)

Study Design: Retrospective comparative cohort study., Objective: Assess the incidence, risk factors, and outcomes of recurrent proximal junctional kyphosis (r-PJK) in PJK revision patients., Summary of Background Data: Several studies have identified the incidence and risk factors for PJK after primary surgery. However, few studies have reported on PJK recurrence after revision for PJK., Methods: A multicenter database of patients who underwent PJK revision surgery with minimum 2-year follow-up was analyzed. Demographic, operative, and radiographic outcomes were compared in patients with r-PJK and patients without recurrence no-Proximal Junctional Kyphosis (n-PJK). Postoperative Scoliosis Research Society-22r, Short Form-36, and Oswestry Disability Index were compared. Preoperative and most recent spinopelvic, cervical, and cervicothoracic radiographic parameters were compared. Univariate and multivariate analyses were used to determine r-PJK risk factors. A predictive model was formulated based on our logistic regression analysis., Results: A total of 70 patients met the inclusion criteria with an average follow-up of 21.8 months. The mean age was 66.3 ± 9.4 and 80% of patients were women. Before revision, patients had a proximal junctional angle angle of -31.7° ± 15.9°. The rate of recurrent PJK was 44.3%. Logistic regression showed that pre-revision thoracic pelvic angle (odds ratio [OR]: 1.060 95% confidence interval [CI] 1.002; 1.121; P = 0.042) and prerevision C2-T3 sagittal vertical axis (SVA; OR: 1.040 95% CI [1.007; 1.073] P = 0.016) were independent predictors of r-PJK. Classification with these parameters yielded an accuracy of 72.7%, precision of 80.6%, and recall of 73.5%. When examining correction, or change in alignment with revision surgery, we found that change in SVA (OR: 0.981 95% CI [0.968; 0.994] P = 0.005) was the only predictor of r-PJK with accuracy of 66.7%, precision of 74.2%, and recall of 69.7%., Conclusion: Patients after PJK revision surgery had a recurrence rate of 44%. Logistic regression based on the prerevision variables showed that prerevision thoracic pelvic angle and prerevision C2-T3 SVA were independent predictors of r-PJK., Level of Evidence: 4.

Purpose: The thoracolumbar junction (TLJ) has not been explored in regard to its contribution to global sagittal alignment. This study aims to define novel sagittal parameters of the TLJ and to assess their roles within global sagittal alignment., Methods: Included for cross-sectional, retrospective analysis were asymptomatic volunteers and symptomatic patients who had undergone operation for adult spinal deformity. Unique sagittal parameters of the TLJ were measured using the midline of the T12-L1 disk space: The TLJ orientation [TLJO; thoracolumbar tilt (TLT) and slope (TLS)]. Thoracic kyphosis (TK; T5-12), C7-S1 sagittal vertical axis (SVA), lumbar lordosis (LL; L1-S1), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured. Continuous variables were compared using the independent t test. Pearson correlations examined relationships between the parameters in each group. The asymptomatic TK was calculated using the measurement of the asymptomatic volunteer's TLJO by linear regression., Results: One hundred fifteen asymptomatic volunteers and 127 symptomatic patients were included. Only LL among the lumbopelvic parameters correlated with TK (asymptomatic volunteers: r = - 0.42; symptomatic patients: r = - 0.40). All the pelvic parameters have no direct correlation with TK in both groups. TLJO had stronger correlation with TK [asymptomatic volunteers: r = - 0.68 (TLS), r = 0.41 (TLT); symptomatic patients: r = - 0.56 (TLS), r = 0.44 (TLT)] than the lumbopelvic parameters. TLS correlated with LL (asymptomatic volunteers: r = 0.78; symptomatic patients: r = 0.73). Most pelvic parameters correlated with TLJO except for PI. The asymptomatic TK was estimated by the derived formula: 20.847 + TLS × (- 1.198)., Conclusion: The TLJO integrates the status of the lumbopelvic sagittal parameters and simultaneously correlates with thoracic and global sagittal alignment. These slides can be retrieved under Electronic Supplementary Material.

Background Context: The postoperative recovery patterns of cervical deformity patients, thoracolumbar deformity patients, and patients with combined cervical and thoracolumbar deformities, all relative to one another, is not well understood. Clear objective benchmarks are needed to quantitatively define a "good" versus a "bad" postoperative recovery across multiple follow-up visits, varying deformity types, and guide expectations., Purpose: To objectively define and compare the complete 2-year postoperative recovery process among operative cervical only, thoracolumbar only, and combined deformity patients using area-under-the-curve (AUC) methodology., Study Design/setting: Retrospective review of 2 prospective, multicenter adult cervical and spinal deformity databases., Patient Sample: One hundred seventy spinal deformity patients., Outcome Measures: Common health-related quality of life (HRQOL) assessments across both databases included the EuroQol 5-Dimension Questionnaire and Numeric Rating Scale (NRS) back pain assessment. In order to compare disability improvements, the Neck Disability Index (NDI) and the Oswestry Disability Index (ODI) were merged into one outcome variable, the ODI-NDI. Both assessments are gauged on the same scale, with minimal question deviation. Sagittal Radiographic Alignment was also assessed at pre- and all postoperative time points., Methods: Operative deformity patients >18 years old with baseline (BL) to 2-year HRQOLs were included. Patients were stratified by cervical only (C), thoracolumbar only (T), and combined deformities (CT). HRQOL and radiographic outcomes were compared within and between deformity groups. AUC normalization generated normalized HRQOL scores at BL and all follow-up intervals (6 weeks, 3 months, 1 year, and 2 year). Normalized scores were plotted against follow-up time interval. AUC was calculated for each follow-up interval, and total area was divided by cumulative follow-up length, determining overall, time-adjusted HRQOL recovery (Integrated Health State, IHS). Multiple linear regression models determined significant predictors of HRQOL discrepancies among deformity groups., Results: One hundred seventy patients were included (27 C, 27 T, and 116 CT). Age, BMI, sex, smoking status, osteoporosis, depression, and BL HRQOL scores were similar among groups (p >. 05). T and CT patients had higher comorbidity severities (CCI: C 0.696, T 1.815, CT 1.699, p = .020). Posterior surgical approaches were most common (62.9%) followed by combined (28.8%) and anterior (6.5%). Standard HRQOL analysis found no significant differences among groups until 1-year follow-up, where C patients exhibited comparatively greater NRS back pain (4.88 vs. 3.65 vs. 3.28, p = .028). NRS Back pain differences between groups subsided by 2-years (p>.05). Despite C patients exhibiting significantly faster ODI-NDI minimal clinically important difference (MCID) achievement (33.3% vs. 0% vs. 23.0%, p < .001), all deformity groups exhibited similar ODI-NDI MCID achievement by 2-years (51.9% vs. 59.3% vs. 62.9%, p = 0.563). After HRQOL normalization, similar results were observed relative to the standard analysis (1-year NRS Back: C 1.17 vs. T 0.50 vs. CT 0.51, p < .001; 2-year NRS Back: 1.20 vs. 0.51 vs. 0.69, p = .060). C patients exhibited a worse NRS back normalized IHS (C 1.18 vs. T 0.58 vs. CT 0.63, p = .004), indicating C patients were in a greater state of postoperative back pain for a longer amount of time. Linear regression models determined postoperative distal junctional kyphosis (adjusted beta: 0.207, p = .039) and osteoporosis (adjusted beta: 0.269, p = .007) as the strongest predictors of a poor NRS back IHS (model summary: R 2  = 0.177, p = .039)., Conclusions: Despite C patients exhibiting a quicker rate of MCID disability (ODI-NDI) improvement, they exhibited a poorer overall recovery of back pain with worse NRS back scores compared with BL status and other deformity groups. Postoperative distal junctional kyphosis and osteoporosis were identified as primary drivers of a poor postoperative NRS back IHS. Utilization of the IHS, a single number adjusting for all postoperative HRQOL visits, in conjunction with predictive modelling may pose as an improved method of gauging the effect of surgical details and complications on a patient's entire recovery process., (Copyright © 2019. Published by Elsevier Inc.)

OBJECTIVE: Numerous studies have attempted to delineate the normative value for T1S-CL (T1 slope minus cervical lordosis) as a marker for both cervical deformity and a goal for correction similar to how PI-LL (pelvic incidence-lumbar lordosis) mismatch informs decision making in thoracolumbar adult spinal deformity (ASD). The goal of this study was to define the relationship between T1 slope (T1S) and cervical lordosis (CL). METHODS: This is a retrospective review of a prospective database. Surgical ASD cases were initially analyzed. Analysis across the sagittal parameters was performed. Linear regression analysis based on T1S was used to provide a clinically applicable equation to predict CL. Findings were validated using the postoperative alignment of the ASD patients. Further validation was then performed using a second, normative database. The range of normal alignment associated with horizontal gaze was derived from a multilinear regression on data from asymptomatic patients. RESULTS: A total of 103 patients (mean age 54.7 years) were included. Analysis revealed a strong correlation between T1S and C0-7 lordosis (r = 0.886), C2-7 lordosis (r = 0.815), and C0-2 lordosis (r = 0.732). There was no significant correlation between T1S and T1S-CL. Linear regression analysis revealed that T1S-CL assumed a constant value of 16.5° (R2 = 0.664, standard error 2°). These findings were validated on the postoperative imaging (mean absolute error [MAE] 5.9°). The equation was then applied to the normative database (MAE 6.7° controlling for McGregor slope [MGS] between -5° and 15°). A multilinear regression between C2-7, T1S, and MGS demonstrated a range of T1S-CL between 14.5° and 26.5° was necessary to maintain horizontal gaze. CONCLUSIONS: Normative CL can be predicted via the formula CL = T1S - 16.5° ± 2°. This implies a threshold of deformity and aids in providing a goal for surgical correction. Just as pelvic incidence (PI) can be used to determine the ideal LL, T1S can be used to predict ideal CL. This formula also implies that a kyphotic cervical alignment is to be expected for individuals with a T1S < 16.5°.

Background: Proximal junctional kyphosis (PJK) following adult spinal deformity (ASD) surgery is a well-documented complication, but associations between radiographic PJK and cervical malalignment onset remain unexplored., Objective: To study cervical malalignment in ASD surgical patients that develop PJK., Methods: Retrospective review of prospective multicenter database. Inclusion: primary ASD patients (≥5 levels fused, upper instrumented vertebra [UIV] at T2 or above, and 1-yr minimum follow-up) without baseline cervical deformity (CD), defined as ≥2 of the following criteria: T1 slope minus cervical lordosis < 20°, cervical sagittal vertical axis < 4 cm, C2-C7 cervical lordosis < 10°. PJK presence (<10° change in UIV and UIV + 2 kyphosis) and angle were identified 1 yr postoperative. Propensity score matching between PJK and nonPJK groups controlled for baseline alignment. Preoperative and 1-yr postoperative cervical alignment were compared between PJK and nonPJK patients., Results: One hundred sixty-three patients without baseline CD (54.9 yr, 83.9% female) were included. PJK developed in 60 (36.8%) patients, with 27 (45%) having UIV above T7. PJK patients had significantly greater baseline T1 slope in unmatched and propensity score matching comparisons (P < .05). At 1 yr postoperative, PJK patients had significantly higher T1 slope (P < .001), C2-T3 Cobb (P = .04), and C2-T3 sagittal vertical axis (P = .02). New-onset CD rate in PJK patients was 15%, and 16.5% in nonPJK patients (P > .05). Increased PJK magnitude was associated with increasing T1 slope and C2-T3 SVA (P < .05)., Conclusion: Patients who develop PJK following surgical correction of ASD have a 15% incidence of development of new-onset CD. Patients developing PJK following surgical correction of ASD tend to have an increased preoperative T1 slope. Increased progression of C2-T3 Cobb angle and C2-T3 SVA are associated with development of PJK following surgical correction of thoracolumbar deformity.

Background: Pseudarthrosis and rod fracture (RF) remain significant concerns after fusion for adult spinal deformity (ASD). Although a radiographic system of fusion grade has been proposed, the correlation between fusion grade and health-related quality of life measures (HRQoL) is not known., Methods: In a retrospective review of a prospectively collected clinical database, patients that underwent ≥5-level posterior instrumented arthrodesis for ASD were evaluated. Fusion grade was determined on plain films using the Lenke criteria. Patients were grouped as 1) complete fusion (grade I or II at all levels), 2) incomplete fusion (grade 3 or 4 at any level), 3) rod fracture without revision (RF), and 4) rod fracture with revision (RFR). Outcome measures were the Oswestry Disability Index, Medical Outcomes Study 36-Item Short-Form Health Survey Physical and Mental Component Summaries, Scoliosis Research Society-22r total, and Lumbar Stiffness and Disability Index., Results: There were 205 (85%) patients who achieved the minimum 2-year follow-up and were included. Complete fusion was achieved in 115 patients (56.1%), 55% patients (26.8%) had incomplete fusion, and 35% patients (17.1%) had RF. Of the 35 patients with RF, 19 (17.1%; 19/205) underwent revision while 16 (7.8%; 16/205) had RF without revision. HRQoL measures were significantly worse in the RFR group, whereas no significant differences were found between groups 1, 2, and 3., Conclusions: Radiographic fusion grade after ASD surgery did not significantly impact HRQoL in the absence of RF. RFR was associated with significantly worse clinical outcomes. Fusion grade may be less predictive of clinical outcomes than the occurrence of RF., (Copyright © 2018. Published by Elsevier Inc.)

Study Design: Prospective multicenter cohort study with consecutive enrollment., Objective: To evaluate preoperative alignment and surgical factors associated with suboptimal early postoperative radiographic outcomes after surgery for cervical deformity., Summary of Background Data: Recent studies have demonstrated correlation between cervical sagittal alignment and patient-reported outcomes. Few studies have explored cervical deformity correction prospectively, and the factors that result in successful versus failed cervical alignment corrections remain unclear., Methods: Patients with adult cervical deformity (ACD) included with either cervical kyphosis more than 10°, C2-C7 sagittal vertical axis (cSVA) of more than 4 cm, or chin-brow vertical angle of more than 25°. Patients were categorized into failed outcomes group if cSVA of more than 4 cm or T1 slope and cervical lordosis (TS-CL) of more than 20° at 6 months postoperatively., Results: A total of 71 patients with ACD (mean age 62 yr, 56% women, 41% revisions) were included. Fourty-five had primary cervical deformities and 26 at the cervico-thoracic junction. Thirty-three (46.4%) had failed radiographic outcomes by cSVA and 46 (64.7%) by TS-CL. Failure to restore cSVA was associated with worse preoperative C2 pelvic tilt angle (CPT: 64.4° vs. 47.8°, P = 0.01), worse postoperative C2 slope (35.0° vs. 23.8°, P = 0.004), TS-CL (35.2° vs. 24.9°, P = 0.01), CPT (47.9° vs. 28.2°, P < 0.001), "+" Schwab modifiers (P = 0.007), revision surgery (P = 0.05), and failure to address the secondary, thoracolumbar driver of the deformity (P = 0.02). Failure to correct TS-CL was associated with worse preoperative cervical kyphosis (10.4° vs. -2.1°, P = 0.03), CPT (52.6° vs. 39.1°, P = 0.04), worse postoperative C2 slope (30.2° vs. 13.3°, P < 0.001), cervical lordosis (-3.6° vs. -15.1°, P = 0.01), and CPT (37.7° vs. 24.0°, P < 0.001). Multivariate analysis revealed postoperative distal junctional kyphosis associated with suboptimal outcomes by cSVA (odds ratio 0.06, confidence interval 0.01-0.4, P = 0.004) and TS-CL (odds ratio 0.15, confidence interval 0.02-0.97, P = 0.05)., Conclusion: Factors associated with failure to correct the cSVA included revision surgery, worse preoperative CPT, and concurrent thoracolumbar deformity. Failure to correct the TS-CL mismatch was associated with worse preoperative cervical kyphosis and CPT. Occurrence of early postoperative distal junctional kyphosis significantly affects postoperative radiographic outcomes., Level of Evidence: 3.

Background: Pedicle subtraction osteotomy (PSO) can be used to treat rigid sagittal plane deformities. Nonunions and rod breakages are known complications of PSO., Objective: To assess outcomes of 2 methods of posterior instrumentation for PSO, traditional 2 rods vs a novel 4-rod technique in which 2 additional rods span only the osteotomy level., Methods: This study was a retrospective, radiographic review of consecutive PSOs performed at 2 centers. The primary difference in technique between the centers was the use of 4 rods including 2 independent rods attached only to the vertebral levels immediately adjacent to the PSO (group 1, n = 29 patients) vs the traditional 2-rod technique (group 2, n = 20 patients)., Results: Demographics and preoperative to postoperative radiographic measurements were similar between the study groups, including the PSO wedge resection angle (P = .56). The rod breakage rate was 25% with 2 rods and 0% with 4 rods (P = .008), and the pseudarthrosis rate with 2 rods was 25% and with 4 rods was 3.4% (P = .035). The patient with pseudarthrosis from group 1 had an infection and developed pseudarthrosis only after instrumentation removal. Rates of other complications did not differ significantly between the study groups., Conclusion: This study provides a comparison between 2 techniques for rod placement across a PSO and suggests that the described novel 4-rod technique may help to reduce the rates of pseudarthrosis and rod failure. It will be important to confirm these findings in a prospectively designed study with multiple institutions in order to better control for potentially confounding factors.

Background: Few reports have focused on treatment of adult cervical deformity (ACD)., Objective: To present early complication rates associated with ACD surgery., Methods: A prospective multicenter database of consecutive operative ACD patients was reviewed for early (≤30 days from surgery) complications. Enrollment required at least 1 of the following: cervical kyphosis >10 degrees, cervical scoliosis >10 degrees, C2-7 sagittal vertical axis >4 cm, or chin-brow vertical angle >25 degrees., Results: Seventy-eight patients underwent surgical treatment for ACD (mean age, 60.8 years). Surgical approaches included anterior-only (14%), posterior-only (49%), anterior-posterior (35%), and posterior-anterior-posterior (3%). Mean numbers of fused anterior and posterior vertebral levels were 4.7 and 9.4, respectively. A total of 52 early complications were reported, including 26 minor and 26 major. Twenty-two (28.2%) patients had at least 1 minor complication, and 19 (24.4%) had at least 1 major complication. Overall, 34 (43.6%) patients had at least 1 complication. The most common complications included dysphagia (11.5%), deep wound infection (6.4%), new C5 motor deficit (6.4%), and respiratory failure (5.1%). One (1.3%) mortality occurred. Early complication rates differed significantly by surgical approach: anterior-only (27.3%), posterior-only (68.4%), and anterior-posterior/posterior-anterior-posterior (79.3%) (P = .007)., Conclusion: This report provides benchmark rates for overall and specific ACD surgery complications. Although the surgical approach(es) used were likely driven by the type and complexity of deformity, there were significantly higher complication rates associated with combined and posterior-only approaches compared with anterior-only approaches. These findings may prove useful in treatment planning, patient counseling, and ongoing efforts to improve safety of care., Abbreviations: 3CO, 3-column osteotomiesACD, adult cervical deformityEBL, estimated blood lossISSG, International Spine Study groupSVA, sagittal vertical axis.

Study Design: A retrospective review of a prospective multicenter database., Objective: The aim of this study was to identify variables associated with extended length of stay (ExtLOS) and this impact on health-related quality of life (HRQoL) scores in adult spinal deformity (ASD) patients., Summary of Background Data: ASD surgery is complex and associated with complications including extLOS. Although variables contributing to extLOS have been considered, specific complications and pre-disposing factors among ASD surgical patients remain to be investigated., Inclusion Criteria: ASD surgical patients (age >18 years, scoliosis ≥20°, sagittal vertical axis ≥5 cm, pelvic tilt ≥25°, and/or thoracic kyphosis >60°) with complete demographic, radiographic, and HRQoL data at baseline, 6 weeks, and 2 years postoperative. ExtLOS was based on 75th percentile (≥9 days). Univariate and multivariate analyses identified predictors and evaluated effects on outcomes. Repeated-measures mixed models analyzed impact of ExtLOS on HRQoL [Oswestry Disability Index; Short Form-36 physical component summary/mental component summary; SRS22r Activity (AC), Pain (P), Appearance (AP), Satisfaction (S), Mental (M) and Total (T)]., Results: Three hundred eighty patients met inclusion criteria: 105 (27.6%) had extLOS (≥9 days) and 275 (72.4%) did not. Average LOS was 8 days (range: 1-30 days). Age [odds ratio (OR) 1.04], no. of levels fused (OR 1.12), no. of infections (OR 2.29), no. of neurologic complications (OR 2.51), Charlson Comorbidity Index Score (CCI) predicted ExtLOS (OR 3.92), and no. of intraop complications predicted ExtLOS (OR 3.56). ExtLOS patients had more intracardiopulmonary (pleural effusion: 1.9% vs. 0%) and operative complications (dural tear: 13.3% vs. 5.1%; excessive blood loss: 18% vs. 5.8%) (P < 0.022). At 2 years, both groups of patients experienced an overall improvement in all HRQoL scores (P < 0.001). ExtLOS patients had significantly less overall improvement in all HRQoLs (P < 0.01) except for MCS (P = 0.17) and SRS M (P = 0.08)., Conclusion: Extended LOS of ASD patients is affected by comorbidities (higher CCI) and number of intraoperative, but not peri-operative, complications. All patients improved overall in HRQoL scores, but extended LOS patients improved less overall at 2 years in comparison., Level of Evidence: 3.

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.

Background: Posterior vertebral column resection (PVCR) is a challenging but effective technique for the correction of complex spinal deformity. However, it has a high complication rate and carries a substantial risk for neurologic injury., Purpose: The aim was to test whether the apex of the deformity influences the clinical outcomes and complications in patients undergoing PVCR., Study Design: A historical cohort was recruited from a single center and evaluated preoperatively, postoperatively, and at final follow-up., Patient Sample: Ninety-eight hyperkyphotic patients undergoing PVCR were included. Inclusion criteria consisted of kyphoscoliosis and hyperkyphosis surgically treated with PVCR as a primary or revision procedure., Outcome Measures: The outcome measures included a number of neurologic complications., Methods: Receiver operator characteristic (ROC) curve analysis and Youden index (J) were used to estimate the optimum cut-off to predict neurologic complications for each potential risk factor. In three ROC analyses, we included separately body mass index (BMI), kyphosis degree, and age as independent variables and neurologic complications as the dependent variable. Logistic regression was used to estimate the odds ratios (ORs) and construct 95% confidence intervals (CIs)., Results: Among the 98 patients, the etiologies were: post infectious (50), congenital (31), and others (17). The averages were: age 14±6.5 years, BMI 20±10 kg/m(2), American Society of Anesthesiologists 3±0.7, forced vital capacity 76±23%, fusion levels 10±3, estimated blood loss 1,319±720 mL, surgical time 375±101 minutes, and preoperative localized kyphosis 104±30°. Thirty-three patients had abnormal preoperative neurologic status. Major complications occurred in 46 patients (neurologic in 25). The apex of kyphosis was proximal thoracic T1-T5 (five patients), thoracic (TH) T6-T9 (17 patients), thoracolumbar T10-L2 (55 patients), and lumbar L3-S1 (nine patients). The level of apex and BMI were independent risk factors for neurologic complications: TH apex (OR: 101.30, 95% CI: 1.420-infinite; p=.037); BMI (OR: 1.92, 95% CI: 1.110-infinite; p=.026)., Conclusions: Posterior vertebral column resection for severe spine deformity is technically demanding and carries a substantial risk. The apex is a variable that influences the occurrence of neurologic complications, and the presence of a TH apex in particular could be a preoperative risk factor for neurologic complications., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background Context: Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment on achieving optimal thoracolumbar alignment in ASD surgery is unclear., Purpose: This study assesses the relationship between preoperative (preop) cervical spinal parameters and global alignment after thoracolumbar ASD surgery at 2-year follow-up., Study Design/setting: This study is a retrospective review of a multicenter, prospective database., Patient Sample: Surgical ASD patients with 2-year follow-up and cervical X-rays were included., Outcome Measures: The outcome measures were radiographic parameters and self-reported health-related quality-of-life measures (Short-Form 36 [SF-36], Oswestry Disability Index [ODI], and Scoliosis Research Society 22 [SRS-22])., Methods: Surgical ASD patients of 18 years and older with scoliosis greater than or equal to 20° and one of the following radiographic parameters were included: sagittal vertical axis (SVA) greater than or equal to 5 cm, pelvic tilt (PT) greater than or equal to 25°, or thoracic kyphosis (TK) greater than 60°. The SRS-Schwab sagittal modifiers (PT, global alignment, and pelvic incidence and lumbar lordosis [PI-LL]) were assessed at 2-year postoperatively as either normal ("0") or abnormal ("+" or "++"). Patients were classified in the aligned group (AG) or malaligned group (MG) at 2-year follow-up if all three sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2-C7 SVA greater than 4 cm, C2-C7 SVA less than 4 cm, cervical kyphosis (CL greater than 0), cervical lordosis (CL less than 0), any deformity (C2-C7 SVA greater than 4 cm or CL greater than 0), and both CD (C2-C7 SVA greater than 4 cm and CL greater than 0). Univariate testing was performed using t or chi-square test, looking at the following preop parameters: CD, C2-C7 SVA, C2-T3 SVA, CL, T1 slope (T1S), T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL., Results: One hundred four patients met the initial inclusion criteria with 70 in the AG and 34 in MG. Preoperative, patients in the MG had a higher CL (11.7 vs. 4.9, p=.03), higher C2-T3 angle (13.59 vs 4.9 p=.01), higher PT (p<.0001), higher SVA (p<.0001), and higher PI-LL (p<.0001) compared with the AG. Interestingly, the prevalence of CD at baseline was similar for both groups. There was no statistically significant difference among groups in the amount of improvement more than 2 years on the ODI or the Physical Component Summary of SF-36., Conclusions: Patients with sagittal spinal malalignment associated with significant cervical compensatory lordosis are at increased risk of realignment failure at 2-year follow-up. Assessment of the degree of cervical compensation may be helpful in preop evaluation to assist in realignment outcome prediction., (Copyright © 2015 Elsevier Inc. All rights reserved.)

OBJECT Alignment changes in the cervical spine that occur following surgical correction for thoracic deformity remain poorly understood. The purpose of this study was to evaluate such changes in a cohort of adults with thoracic deformity treated surgically. METHODS The authors conducted a multicenter retrospective analysis of consecutive patients with thoracic deformity. Inclusion criteria for this study were as follows: corrective osteotomy for thoracic deformity, upper-most instrumented vertebra (UIV) between T-1 and T-4, lower-most instrumented vertebra (LIV) at or above L-5 (LIV ≥ L-5) or at the ilium (LIV-ilium), and a minimum radiographic follow-up of 2 years. Sagittal radiographic parameters were assessed preoperatively as well as at 3 months and 2 years postoperatively, including the C-7 sagittal vertical axis (SVA), C2-7 cervical lordosis (CL), C2-7 SVA, T-1 slope (T1S), T1S minus CL (T1S-CL), T2-12 thoracic kyphosis (TK), apical TK, lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), and sacral slope (SS). RESULTS Fifty-seven patients with a mean age of 49.1 ± 14.6 years met the study inclusion criteria. The preoperative prevalence of increased CL (CL > 15°) was 48.9%. Both 3-month and 2-year apical TK improved from baseline (p < 0.05, statistically significant). At the 2-year follow-up, only the C2-7 SVA increased significantly from baseline (p = 0.01), whereas LL decreased from baseline (p < 0.01). The prevalence of increased CL was 35.3% at 3 months and 47.8% at 2 years, which did not represent a significant change. Postoperative cervical alignment changes were not significantly different from preoperative values regardless of the LIV (LIV ≥ L-5 or LIV-ilium, p > 0.05 for both). In a subset of patients with a maximum TK ≥ 60° (35 patients) and 3-column osteotomy (38 patients), no significant postoperative cervical changes were seen. CONCLUSION Increased CL is common in adult spinal deformity patients with thoracic deformities and, unlike after lumbar corrective surgery, does not appear to normalize after thoracic corrective surgery. Cervical sagittal malalignment (C2-7 SVA) also increases postoperatively. Surgeons should be aware that spontaneous cervical alignment normalization might not occur following thoracic deformity correction.

Object: Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD., Methods: This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°., Results: Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8)., Conclusions: Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

Study Design: Multicenter, prospective, consecutive case series., Objective: To assess prevalence and type of cervical deformity among adults with thoracolumbar (TL) deformity and to assess for associations between cervical deformities and different types of TL deformities., Summary of Background Data: Cervical deformity can present concomitantly with TL deformity and have implications for the management of TL deformity., Methods: Multicenter, prospective, consecutive series of adult (age >18 yr) patients with TL deformity. Parameters included pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), C2-C7 sagittal vertical axis (C2-C7SVA), C7-S1SVA, and C2-C7 lordosis. Cervical deformity was defined as cervical lordosis more than 0° (cervical kyphosis [CK]) or C2-C7SVA more than 4 cm (cervical positive sagittal malalignment [CPSM]). Patients were stratified by the Scoliosis Research Society-Schwab classification of adult TL deformity, including curve type (N = sagittal deformity, T = thoracic scoliosis, L = lumbar scoliosis, and D = T + L scoliosis) and modifier grades: PT (0: <20°, +: 20°-30°, ++: >30°), C7-S1SVA (0: <4 cm, +: 4-9.5 cm, ++: >9.5 cm), and PI-LL mismatch (0: <10°, +: 10-20°, ++: >20°)., Results: A total of 470 patients met criteria (mean age = 52 yr). Mean cervical lordosis and C2-C7SVA were -8° and 3.2 cm, respectively. CK and CPSM prevalence were 31% and 29%, respectively, and prevalence of CK and/or CPSM was 53%. CK prevalence differed by curve type (N = 15%, L = 27%, D = 37%, T = 49%; P < 0.001); CPSM prevalence did not differ by curve type (P = 0.19). Higher PT grades had lower CK prevalence (0 = 40%, += 27%, ++= 15%; P < 0.001) but greater CPSM prevalence (0 = 23%, += 28%, ++= 45%; P = 0.001). Similarly, higher SVA grades had lower CK prevalence (0 = 40%, += 23%, ++= 11%; P < 0.001) but greater CPSM prevalence (0 = 24%, += 24%, ++= 48%; P < 0.001). Higher PI-LL grades had lower CK prevalence (0 = 35%, += 31%, ++= 22%; P = 0.034) but no CPSM association (P = 0.46)., Conclusion: Cervical deformity is highly prevalent (53%) in adult TL deformity. C7-S1SVA, PT, and PI-LL modifiers are associated with cervical deformity prevalence. These findings suggest that TL deformity evaluation should include assessment for concomitant cervical deformity and that further study is warranted to define their potential clinical impact., Level of Evidence: 3.