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Purpose: Three-column osteotomies (3COs), such as pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR), are used to surgically correct rigid adult spinal deformity (ASD). While extensive research exists about complications associated with 3COs, there remains a paucity of studies analyzing risk factors for mortality following 3CO. We believe the mortality rate after 3-column osteotomy will be low with specific identifiable demographic or medical risk factors. Methods: A retrospective analysis was conducted using the National Surgical Quality Improvement Program (NSQIP) database. Patients undergoing 3CO were identified via CPT codes. The primary outcome of interest was 30-day postoperative mortality. Univariate statistical analysis was performed, followed by multivariable logistic regression controlling for age, sex, and body mass index (BMI). Results: The analysis included 1,441 patients. 446 patients had thoracic osteotomies, 996 patients had lumbar osteotomies, and 226 had multilevel osteotomies. The overall 30-day mortality rate was 1.2% (18 patients). On univariate analysis, mortality was more likely in patients with diabetes (2.8% vs. 1.2%, P = 0.029) and COPD (7.0% vs. 1.2%, P < 0.001). Mortality was associated with higher 5-factor modified frailty index (P = 0.004). After controlling for age, sex, and BMI, multivariable analysis revealed that mortality rates were independently associated with longer operative times (OR = 1.28, 95% CI:1.06–1.54, P = 0.010) and COPD (OR = 10.36, 95% CI: [2.17–49.47], P = 0.003). Conclusion: Thirty-day mortality after 3CO is 1.2% globally. The greatest univariate risk factors are diabetes, COPD, and frailty. Regardless of age, sex, or BMI, it was found that COPD and duration of surgery were independently associated with increased rates of mortality. [ABSTRACT FROM AUTHOR]

(1) Background: The correction of adult spinal deformity (ASD) can require long, complex constructs with multiple rods which traverse important biomechanical levels to achieve multi-pelvic fixation. Minimally invasive (MIS) placement of these constructs has historically been difficult. Advanced technologies such as spinal robotics platforms can facilitate the design and placement of these constructs and further enable these surgical approaches in MIS deformity surgery. (2) Methods: A retrospective study was performed on a series of ASD patients undergoing MIS deformity correction with ≥eight fusion levels to the lower thoracic spine with preoperative robotic construct planning and robot-assisted pedicle screw placement. (3) Results: There were 12 patients (10 female, mean age 68.6 years) with a diagnosis of either degenerative scoliosis (8 patients) or sagittal imbalance (4 patients). All underwent preoperative robotic planning to assist in MIS robot-assisted percutaneous or transfascial placement of pedicle and iliac screws with multiple-rod constructs. Mean operative values per patient were 9.9 levels instrumented (range 8-11), 3.9 interbody cages (range 2-6), 3.3 iliac fixation points (range 2-4), 3.3 rods (range 2-4), 18.7 screws (range 13-24), estimated blood loss 254 cc (range 150-350 cc), and operative time 347 min (range 242-442 min). All patients showed improvement in radiographic sagittal, and, if applicable, coronal parameters. Mean length of stay was 5.8 days with no ICU admissions. Ten patients ambulated on POD 1 or 2. Of 224 screws placed minimally invasively, four breaches were identified on intraoperative CT and repositioned (three lateral, one medial) for a robot-assisted screw accuracy of 98.2%. (4) Conclusions: Minimally invasive long-segment fixation for adult spinal deformity surgery has historically been considered laborious and technically intensive. Preoperative robotics planning facilitates the design and placement of even complex multi-rod multi-pelvic fixation for MIS deformity surgery.

Purpose: To evaluate outcomes of choosing different Roussouly shapes and improving in Schwab modifiers for surgical Roussouly type 1 patients. Methods: Baseline (BL) and 2-year (2Y) clinical data of adult spinal deformity (ASD) patients presenting with Roussouly type 1 sagittal spinal alignment were isolated in the single-center spine database. Patients were grouped into Roussouly type 1, 2 and 3 with anteverted pelvis (3a) postoperatively. Schwab modifiers at BL and 2Y were categorized as follows: no deformity (0), moderate deformity (+), and severe deformity (++) for pelvic tilt (PT), sagittal vertical axis (SVA), and pelvic incidence and lumbar lordosis mismatch (PI-LL). Improvement in SRS-Schwab was defined as a decrease in the severity of any modifier at 2Y. Results: A total of 96 patients (69.9 years, 72.9% female, 25.2 kg/m2) were included. At 2Y, there were 34 type 1 backs, 60 type 2 backs and only 2 type 3a. Type 1 and type 2 did not differ in rates of reaching 2Y minimal clinically important difference (MCID) for health-related quality of life (HRQOL) scores (all P > 0.05). Two patients who presented with type 3a had poor HRQOL scores. Analysis of Schwab modifiers showed that 41.7% of patients improved in SVA, 45.8% in PI-LL, and 36.5% in PT. At 2Y, patients who improved in SRS-Schwab PT and SVA had lower Oswestry disability index (ODI) scores and significantly more of them reached MCID for ODI (all P < 0.001). Patients who improved in SRS-Schwab SVA and PI-LL had more changes of VAS Back and Short Form-36 (SF-36) outcomes questionnaire physical component summary (SF-36 PCS), and significantly more reached MCID (all P < 0.001). By 2Y, type 2 patients who improved in SRS-Schwab grades reached MCID for VAS back and ODI at the highest rate (P = 0.003, P = 0.001, respectively), and type 1 patients who improved in SRS-Schwab grades reached MCID for SF-36 PCS at the highest rate (P < 0.001). Conclusion: For ASD patients classified as Roussouly type 1, postoperative improvement in SRS-Schwab grades reflected superior patient-reported outcomes while type 1 and type 2 did not differ in clinical outcomes at 2Y. However, development of type 3a should be avoided at the risk of poor functional outcomes. Utilizing both classification systems in surgical decision-making can optimize postoperative outcomes. [ABSTRACT FROM AUTHOR]

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results—a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)—could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF. [ABSTRACT FROM AUTHOR]

Study Design. Retrospective Cohort Study. Objective. To assess if there is a threshold of baseline disability beyond which the patient-reported outcomes after surgical correction of adult spinal deformity (ASD) are adversely impacted. Background. Patient-reported outcomes vary after correction of adult spinal deformity, even when patients are optimally realigned. There is a paucity of literature examining the impact of baseline disability on patient-reported outcomes in ASD. Methods. Patients with baseline (BL) and two-year data were included. Disability was ranked according to BL Oswestry Disability Index (ODI) into quintiles: Q1 (lowestODI score) toQ5 (highestODI score). Adjusted logistic regression analyses evaluated the likelihood of reaching =1 MCID in Scoliosis Research Society Outcomes Questionnaire (SRS-22) Pain, SRS-22 Activity, and Short Form-36 physical component summary at two years across disability groups Q1-Q4 with respect to Q5. Sensitivity tests were performed, excluding patients with any "0" Schwab modifiers at BL. Results. Compared with patients in Q5, the odds of reaching MCID in SRS-22 Pain at 2Y were significantly higher for those in Q1 (OR: 3.771), Q2 (OR: 3.006), and Q3 (OR: 2.897), all P<0.021. Similarly, compared with patients in Q5, the odds of reaching MCID in SRS-22 Activity at two years were significantly higher for those in Q2 (OR: 3.454) and Q3 (OR: 2.801), both P<0.02. Lastly, compared with patients in Q5, odds of reaching MCID in Short Form-36 physical component summary at two years were significantly higher for patients in Q1 (OR: 5.350), Q2 (OR: 4.795), and Q3 (OR: 6.229), all P<0.004. Conclusions. This study found that patients presenting with moderate disability at BL (ODI < 40) consistently surpassed healthrelated quality of life outcomes as compared with those presenting with greater levels of disability. We propose that a baseline ODI of 40 represents a disability threshold within which operative inte rvention maximizes patient-reported outcomes. Furthermore, delaying the intervention until patients progress to severe disability may limit the benefits of surgical correction in ASD patients. [ABSTRACT FROM AUTHOR]

Study Design. This was a retrospective study. Objective. To assess the impact of surgical costs on patient-reported outcomes in adult spinal deformity (ASD). Summary of Background Data. With increased focus on delivering cost-effective health care, interventions with highresource utilization, such as ASD surgery, have received greater scrutiny. Materials and Methods. ASD patients aged 18 years and older with BL and 2-year data were included. Surgical costs were calculated using the 2021 average Medicare reimbursement by Current Procedural Terminology code. Costs of complications and reoperations were intentionally excluded. Patients were ranked into tertiles by surgical cost: highest surgical costs (HC) and lowest surgical costs (LC). They were propensity score matched to account for differences in baseline age and deformity. Bivariate logistic regressions assessed odds of achieving outcomes. Results. Four hundred twenty-one patients met inclusion (60.7 yr, 81.8% female, Charlson Comorbidity Index: 1.6, 27.1 kg/m²), 139 LC and 127 HC patients. After propensity score matching, 102 patients remained in each cost group with an average reimbursement of LC: $12,494 versus HC: $29,248. Matched cohorts had similar demographics and baseline health-related quality of life. Matched groups had similar baseline sagittal vertical axis (HC: 59.0 vs. LC: 56.7 mm), pelvic incidence and lumbar lordosis (HC: 13.1 vs. LC: 13.4°), and pelvic tilt (HC: 25.3 vs. LC: 22.4°). Rates of complications were not significantly different between the cost groups. Compared with the LC group, by 2 years, HC patients had higher odds of reaching substantial clinical benefit in Oswestry Disability Index [odds ratio (OR): 2.356 (1.220, 4.551), P= 0.011], in Scoliosis Research Society-Total [OR: 2.988 (1.515, 5.895), P=0.002], and in Numerical Rating Scale Back [OR: 2.739 (1.105, 6.788), P=0.030]. Similar findings were appreciated for HC patients in the setting of Schwab deformity outcome criteria. Conclusions. Although added cost did not guarantee an ideal outcome, HC patients experienced superior patient-reported outcomes compared with LC patients. Although cost efficiency remains an important priority for health policy, isolating cost reduction may compromise outcomes and add to future costs of reintervention, particularly with more severe baseline deformity. [ABSTRACT FROM AUTHOR]

Aims: To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory. Methods: Patients who underwent surgery for ASD, with a minimum of two-year follow-up, were retrospectively reviewed. In total, 210 patients were included and randomly allocated into training (70% of the sample size) and test (the remaining 30%) sets to develop the machine learning algorithm. Risk factors were included in the analysis, along with clinical characteristics and parameters acquired through diagnostic radiology. Results: Overall, 152 patients without and 58 with a history of surgical revision following surgery for ASD were observed; the mean age was 68.9 years (SD 8.7) and 66.9 years (SD 6.6), respectively. On implementing a random forest model, the classification of URO events resulted in a balanced accuracy of 86.8%. Among machine learning-extracted risk factors, URO, proximal junction failure (PJF), and postoperative distance from the posterosuperior corner of C7 and the vertical axis from the centroid of C2 (SVA) were significant upon Kaplan-Meier survival analysis. Conclusion: The major risk factors for URO following surgery for ASD, i.e. postoperative SVA and PJF, and their interactions were identified using a machine learning algorithm and game theory. Clinical benefits will depend on patient risk profiles. Cite this article: Bone Joint Res 2023;12(4):245–255.

Study Design.: Retrospective cohort study. Objective.: Assess whether modifying spinal alignment goals to accommodate frailty considerations will decrease mechanical complications and maximize clinical outcomes. Summary of Background Data.: The Global Alignment and Proportion (GAP) score was developed to assist in reducing mechanical complications, but has had less success predicting such events in external validation. Higher frailty and many of its components have been linked to the development of implant failure. Therefore, modifying the GAP score with frailty may strengthen its ability to predict mechanical complications. Materials and Methods.: We included 412 surgical ASD patients with two-year follow-up. Frailty was quantified using the modified Adult Spinal Deformity Frailty Index (mASD-FI). Outcomes: proximal junctional kyphosis and proximal junctional failure (PJF), major mechanical complications, and "Best Clinical Outcome" (BCO), defined as Oswestry Disability Index<15 and Scoliosis Research Society 22-item Questionnaire Total>4.5. Logistic regression analysis established a six-week score based on GAP score, frailty, and Oswestry Disability Index US Norms. Logistic regression followed by conditional inference tree analysis generated categorical thresholds. Multivariable logistic regression analysis controlling for confounders was used to assess the performance of the frailty-modified GAP score. Results.: Baseline frailty categories: 57% not frail, 30% frail, 14% severely frail. Overall, 39 of patients developed proximal junctional kyphosis, 8% PJF, 21% mechanical complications, 22% underwent reoperation, and 15% met BCO. The mASD-FI demonstrated a correlation with developing PJF, mechanical complications, undergoing reoperation, and meeting BCO at two years (all P <0.05). Regression analysis generated the following equation: Frailty-Adjusted Realignment Score (FAR Score)=0.49×mASD-FI+0.38×GAP Score. Thresholds for the FAR score (0–13): proportioned: <3.5, moderately disproportioned: 3.5–7.5, severely disproportioned: >7.5. Multivariable logistic regression assessing FAR score demonstrated associations with mechanical complications, reoperation, and meeting BCO by two years (all P <0.05), whereas the original GAP score was only significant for reoperation. Conclusion.: This study demonstrated adjusting alignment goals in adult spinal deformity surgery for a patient's baseline frailty status and disability may be useful in minimizing the risk of complications and adverse events, outperforming the original GAP score in terms of prognostic capacity. Level of Evidence.: III. [ABSTRACT FROM AUTHOR]

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results—a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)—could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.

A new formula containing terms for age and sagittal curvature reported by the International Spine Study Group is ideal lumbar lordosis (iLL) = pelvic incidence - 0.3 thoracic kyphosis - 0.5Age + 10. However, there are no reports of whether proximal junctional failure (PJF) can be predicted using this formula. We assessed the utility of this formula in PJF in patients with adult spinal deformity with global kyphosis using the Roussouly classification. Forty-four patients with adult spinal deformity global kyphosis (mean age 70.0 years) who underwent multiple levels of lateral lumbar interbody fusion combined with posterior instrumentation were included. Patients were divided into 2 groups: PJF and non-PJF. Demographic, surgical, and radiological parameters were compared. The iLL was calculated according to the new formula, and spinal parameters were compared preoperatively, immediately after, and at the final follow-up. PJF occurred in 11 of 44 (25.0%) patients. Patients with PJF had a large preoperative and postoperative TK, but there was no statistically significant difference in iLL between PJF and non-PJF patients (33.4° vs. 30.2°, P = 0.357). In addition, there was no statistically significant difference in LL and iLL changes (ΔiLL) immediately after surgery (19.0° vs. 23.4°, P = 0.379). Furthermore, there was no correlation between ΔiLL immediately after surgery and at the final follow-up and the proximal junctional angle at the final follow-up. The results of ΔiLL suggest that overcorrection needs to be addressed but that this new formula, including age adjustment, may not predict PJF. [ABSTRACT FROM AUTHOR]

Background.: Patients with less severe adult spinal deformity (ASD) undergo surgical correction and often achieve good clinical outcomes. However, it is not well understood how much clinical improvement is due to sagittal correction rather than treatment of the spondylotic process. Purpose.: Determine baseline thresholds in radiographic parameters that, when exceeded, may result in substantive clinical improvement from surgical correction. Study Design.: Retrospective. Materials and Methods.: ASD patients with BL and two-year data were included. Parameters assessed: sagittal vertical axis, pelvic incidence–lumbar lordosis mismatch, pelvic tilt, T1 pelvic angle, L1 pelvic angle, L4–S1 lordosis, C2–C7 sagittal vertical axis, C2–T3, C2 slope. Outcomes: Good Outcome (GO) at two years: [meeting either: (1) Substantial Clinical Benefit for Oswestry Disability Index (change >18.8), or (2) Oswestry Disability Index <15 and Scoliosis Research Society Total>4.5]. Binary logistic regression assessed each parameter to determine if correction was more likely needed to achieve GO. Conditional inference tree run machine learning analysis generated baseline thresholds for each parameter, above which, correction was necessary to achieve GO. Results.: We included 431 ASD patients. There were 223 (50%) that achieved a GO by two years. Binary logistic regression analysis demonstrated, with increasing baseline severity in deformity, sagittal correction was more often seen in those achieving GO for each parameter(all P <0.001). Of patients with baseline T1 pelvic angle above the threshold, 95% required correction to meet GO (95% vs. 54%, P <0.001). A baseline pelvic incidence–lumbar lordosis >10° (74% of patients meeting GO) needed correction to achieve GO (odds ratio: 2.6, 95% confidence interval: 1.4–4.8). A baseline C2 slope >15° also necessitated correction to obtain clinical success (odds ratio: 7.7, 95% confidence interval: 3.7–15.7). Conclusions.: Our study highlighted point may be present at which sagittal correction has an outsized influence on clinical improvement, reflecting the line where deformity becomes a significant contributor to disability. These new thresholds give us insight into which patients may be more suitable for sagittal correction, as opposed to intervention for the spondylotic process only, leading to a more efficient utility of surgical intervention for ASD. [ABSTRACT FROM AUTHOR]

Study Design.: A retrospective cohort study. Objective.: To assess whether patient outcomes and cost-effectiveness of adult spinal deformity (ASD) surgery have improved over the past decade. Background.: Surgery for ASD is an effective intervention, but one that is also associated with large initial healthcare expenditures. Changes in the cost profile for ASD surgery over the last decade has not been evaluated previously. Materials and Methods.: ASD patients who received surgery between 2008 and 2019 were included. Analysis of covariance was used to establish estimated marginal means for outcome measures [complication rates, reoperations, health-related quality of life, total cost, utility gained, quality adjusted life years (QALYs), cost-efficiency (cost per QALY)] by year of initial surgery. Cost was calculated using the PearlDiver database and represented national averages of Medicare reimbursement for services within a 30-day window including length of stay and death differentiated by complication/comorbidity, revision, and surgical approach. Internal cost data was based on individual patient diagnosis-related group codes, limiting revisions to those within two years (2Y) of the initial surgery. Cost per QALY over the course of 2008–2019 were then calculated. Results.: There were 1236 patients included. There was an overall decrease in rates of any complication (0.78 vs. 0.61), any reoperation (0.25 vs. 0.10), and minor complication (0.54 vs. 0.37) between 2009 and 2018 (all P <0.05). National average 2Y cost decreased at an annual rate of $3194 (R 2=0.6602), 2Y utility gained increased at an annual rate of 0.0041 (R 2=0.57), 2Y QALYs gained increased annually by 0.008 (R 2=0.57), and 2Y cost per QALY decreased per year by $39,953 (R 2=0.6778). Conclusion.: Between 2008 and 2019, rates of complications have decreased concurrently with improvements in patient reported outcomes, resulting in improved cost effectiveness according to national Medicare average and individual patient cost data. The value of ASD surgery has improved substantially over the course of the last decade. [ABSTRACT FROM AUTHOR]

Study Design: A prospective, multicenter study.Objective: This study clarified the uses and limitations of transcranial motor-evoked potentials (Tc-MEPs) for nerve root monitoring during adult spinal deformity (ASD) surgeries.Summary Of Background Data: Whether Tc-MEPs can detect nerve root injuries (NRIs) in ASD surgeries remains controversial.Materials and Methods: We prospectively analyzed neuromonitoring data from 14 institutions between 2017 and 2020. The subjects were ASD patients surgically treated with posterior corrective fusion using multichannel Tc-MEPs. An alert was defined as a decrease of ≥70% in the Tc-MEP's waveform amplitude from baseline, and NRI was considered as meeting the focal Tc-MEP alerts shortly following surgical procedures with postoperative nerve root symptoms in the selected muscles.Results: A total of 311 patients with ASD (262 women and 49 men) and a mean age of 65.5 years were analyzed. Tc-MEP results revealed 47 cases (15.1%) of alerts, including 25 alerts after 10 deformity corrections, six three-column osteotomies, four interbody fusions, three pedicle screw placements or two decompressions, and 22 alerts regardless of surgical maneuvers. Postoperatively, 14 patients (4.5%) had neurological deterioration considered to be all NRI, 11 true positives, and three false negatives (FN). Two FN did not reach a 70% loss of baseline (46% and 65% loss of baseline) and one was not monitored at target muscles. Multivariate logistic regression analysis revealed that risk factors of NRI were preexisting motor weakness ( P <0.001, odds ratio=10.41) and three-column osteotomies ( P =0.008, odds ratio=7.397).Conclusions: Nerve root injuries in our ASD cohort were partially predictable using multichannel Tc-MEPs with a 70% decrease in amplitude as an alarm threshold. We propose that future research should evaluate the efficacy of an idealized warning threshold (e.g., 50%) and a more detailed evoked muscle selection, in reducing false negatives. [ABSTRACT FROM AUTHOR]

Purpose: Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS fusion, to detect adaptation mechanisms around fused spinal segments. Methods: Sixteen patients aged 53.9 ± 15.9 who underwent LS fusion between L3 and S1 were extracted from the database of an ongoing prospective study. Different spino-pelvic parameters were evaluated on full spine X-rays, standing, then sitting straight. Parameters were compared pre-operative versus post-operative, and on standing versus sitting X-rays. Results: Preliminary results revealed a significantly greater pre-operative pelvic tilt (PT) in sitting than standing posture, (p = 0.020) but not in post-operative (p = 0.087). After surgery, PT was lower in sitting compared to pre-operative (p = 0.034) but not in standing (p = 0.245). L4–S1 lordosis was lower in sitting than standing in pre-operative (p = 0.014) and post-operative (p = 0.021). Surgery decreased segmental lordosis above the fusion (PSL, proximal sagittal lordosis) in sitting (p = 0.039) but not in standing (p = 0.193). No significant differences in thoracic kyphosis (TK) were observed. Fusions down to L5 versus S1 showed no significant differences for PT and PSL, neither in sitting versus standing, nor pre-operative versus post-operative. Conclusion: Before fusion, compared to standing, PT increases in sitting straight posture (pelvic retroversion), and the lumbar spine adapts by decreasing its lordosis, mainly at L4–S1. After fusion, the segments adjacent to the instrumented section, adapt in flexion at lumbosacral and thoracolumbar junctions, i.e. just below and above (PSL). This might have mechanical implications for the occurrence of adjacent segment disease. [ABSTRACT FROM AUTHOR]

Adults with spinal deformity (ASD) are known to have spinal malalignment affecting their quality of life and daily life activities. While walking kinematics were shown to be altered in ASD, other functional activities are yet to be evaluated such as sitting and standing, which are essential for patients’ autonomy and quality of life perception. In this cross-sectional study, 93 ASD subjects (50 ± 20 years; 71 F) age and sex matched to 31 controls (45 ± 15 years; 18 F) underwent biplanar radiographic imaging with subsequent calculation of standing radiographic spinopelvic parameters. All subjects filled HRQOL questionnaires such as SF36 and ODI. ASD were further divided into 34 ASD-sag (with PT > 25° and/or SVA >5 cm and/or PI-LL >10°), 32 ASD-hyperTK (with only TK >60°), and 27 ASD-front (with only frontal malalignment: Cobb >20°). All subjects underwent 3D motion analysis during the sit-to-stand and stand-to-sit movements. The range of motion (ROM) and mean values of pelvis, lower limbs, thorax, head, and spinal segments were calculated on the kinematic waveforms. Kinematics were compared between groups and correlations to radiographic and HRQOL scores were computed. During sit-to-stand and stand-to-sit movements, ASD-sag had decreased pelvic anteversion (12.2 vs 15.2°), hip flexion (53.0 vs 62.2°), sagittal mobility in knees (87.1 vs 93.9°), and lumbar mobility (L1L3-L3L5: −9.1 vs −6.8°, all p < 0.05) compared with controls. ASD-hyperTK showed increased dynamic lordosis (L1L3–L3L5: −9.1 vs −6.8°), segmental thoracic kyphosis (T2T10–T10L1: 32.0 vs 17.2°, C7T2–T2T10: 30.4 vs 17.7°), and thoracolumbar extension (T10L1–L1L3: −12.4 vs −5.5°, all p < 0.05) compared with controls. They also had increased mobility at the thoracolumbar and upper-thoracic spine. Both ASD-sag and ASD-hyperTK maintained a flexed trunk, an extended head along with an increased trunk and head sagittal ROM. Kinematic alterations were correlated to radiographic parameters and HRQOL scores. Even after controlling for demographic factors, dynamic trunk flexion was determined by TK and PI-LL mismatch (adj. R2 = 0.44). Lumbar sagittal ROM was determined by PI-LL mismatch (adj. R2 = 0.13). In conclusion, the type of spinal deformity in ASD seems to determine the strategy used for sitting and standing. Future studies should evaluate whether surgical correction of the deformity could restore sitting and standing kinematics and ultimately improve quality of life.

Objective: To analyze ideal indication for combined anterior column realignment (ACR) with short posterior spinal fusion (PSF) and posterior column osteotomy (PCO) for preventing proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) patients with lower lumbar kyphosis and compensatory thoracolumbar lordosis. Methods: A retrospective study was conducted. This study included 27 ASD patients (average age of 66.6 years; one male and 26 females) with lower lumbar kyphosis and compensated thoracolumbar lordosis who underwent short PSF with PCO following ACR from 2006 to 2010. The minimum follow‐up period was 5 years. The patients were divided into two groups based on the sagittal vertical axis (SVA) of the last follow‐up radiographs, and a comparative analysis was performed evaluating spino‐pelvic parameters and clinical outcomes including the Oswestry Disability Index (ODI), Visual Analog Scale (VAS), and complications. Results: The mean follow‐up time of included patients was 109.7 months, and the mean number of fused segments was 3.7. The uppermost instrumented vertebra was L2 in 18 patients or L3 in nine patients, and lowermost instrumented vertebra was sacrum in all patients. The mean lumbar lordosis (LL) values in the optimal SVA and suboptimal SVA groups were 4.4° and 4.2° preoperatively (P = 0.639), −48.1° and −35° postoperatively (P = 0.007), and −45.2° and −20.7° at the last follow‐up (P < 0.05). Overcorrection was seen in seven patients in the optimal SVA group, whereas all of the patients of the suboptimal SVA group were in the category of undercorrection (P = 0.021). Pelvic incidence (PI) of optimal SVA group (<50 mm, n = 16) and suboptimal SVA group (≥50 mm, n = 11) was 44.1° and 53.8° (P = 0.009). The prevalence of PJK was significantly higher in the suboptimal SVA group (P = 0.008), and last follow‐up VAS for back pain (P < 0.05), and postoperative and last follow‐up ODI (P = 0.002 and P < 0.05) were statistically larger for the suboptimal group than the optimal group. Conclusions: Combined ACR with short PSF and PCO could effectively prevent sagittal decompensation of PJK and help achieve sagittal balance in the treatment of ASD patients with lower lumbar kyphosis, compensatory thoracolumbar lordosis, and especially low PI (<50°). [ABSTRACT FROM AUTHOR]

Background: There is evidence indicating patients with spinal deformity have impaired postural control and balance issues. Often, previous surgical intervention excludes the older patient from further invasive procedures leaving them with limited treatment options. The purpose of this case is to report on the clinically significant improvement in postural control as measured by force plate after a multimodal treatment program of Chiropractic Biophysics ® (CBP ® ) posture rehabilitation as well as balance rehabilitation in an elderly patient with long-standing spinal deformity including thoracic hyperkyphosis and a T10-L4 Harrington rod instrumentation for thoracolumbar scoliosis., Case Description: A 69-year-old female presented with the main complaint of balance and gait impairment as well as back pain and headaches. Balance assessment on a force plate showed impaired balance, in the vestibular challenging condition (eyed closed; standing on foam). Radiography showed a forward stooped posture and surgical hardware. Treatment was directed at posture by CBP methods and balance rehabilitation by a whole-body vibration exercise program. Treatment progressed over a 10-month period. The patient experienced relief of back pains and headaches. There was a clinically significant improvement in posturography including a 102 cm reduction in center of pressure (COP) path length. There was an inch reduction in forward sagittal stoop., Conclusions: A non-surgical rehabilitation program demonstrated a clinically significant improvement in balance performance in an elderly female diagnosed with osteopenia, spinal deformity, and previous spine deformity surgery. This approach to improving postural stability is important and further investigations should be undertaken., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-23-183/coif). All authors report that this study has received funding support from CBP NonProfit Inc. P.A.O. is a compensated consultant for CBP NonProfit, Inc. J.W.H. is compensated researcher for CBP NonProfit Inc. D.E.H. is the CEO of Chiropractic Biophysics (CBP) and provides post-graduate education to health care providers/physicians. Spine rehabilitation devices are distributed through his company. D.E.H. is the president of CBP NonProfit, Inc.—a not-for-profit spine research foundation. The authors have no other conflicts of interest to declare., (2024 AME Case Reports. All rights reserved.)

Background: Spinal rods used for adult spinal deformity (ASD) correction are usually manufactured straight and bent manually during surgery. Pre-bent patient-specific spinal rods (PSSR) developed with software provide the surgeon with an intraoperative deformity correction consistent with the surgical plan. Our aim was to report clinical and radiological outcomes using PSSR. We investigated rates of junctional complications both proximally [kyphosis (PJK) and failure (PJF)] and distally [failure (DJF)]., Methods: Prospective case series of 20 consecutive patients who underwent ≥4 level ASD surgery with PSSR at a single institution between January 2019 and December 2022. Preoperative, 6-week, 6-month, 12-month, 24-month, and final follow-ups assessed patient satisfaction (Ottawa decision regret questionnaire) and patient reported outcome measures (PROMs) [visual analogue scale (VAS; Back/Leg), Oswestry disability index (ODI), and 12-Item Short Form Survey (SF-12)]. Sagittal spinopelvic parameters [sagittal vertical axis (SVA), pelvic tilt (PT), and pelvic incidence and lumbar lordosis mismatch (PI-LL)] measured by serial EOS scans were performed preoperatively then compared to planned correction and postoperative measures. Interoperative cages (narrow/wide) were placed for interbody support. PJK risk score assessed likelihood of developing kyphosis. Serial computed tomography (CT) imaging assessed complication (fusion/subsidence)., Results: The mean age of the patients (75% female) was 71.9±6.9 years, and the mean follow-up was 25.2±8.6 [7-40] months. Preoperative mean PROMs showed statistically significant overall improvement (P<0.001) postoperatively to final follow-up. Four patients without wide footprint cages at L4/5 or L5/S1, suffered DJF and reported regret undergoing surgery. Statistically significant difference (P<0.001) between preoperative and surgical plan in SVA and PI-LL but not in PT (P=0.058). No statistically significant difference in surgical plan versus the postoperative SVA, PI-LL, and PT (due to difficulty achieving the surgical plan, and also to maintaining the correction). One patient suffered PJF. There was a mean proximal kyphotic angle (PKA) of 17.8±13.0 degrees and PJK risk score of 3.7±1.0 with 40% who experienced PJK. No rod breakages were observed., Conclusions: In this series, PSSR improved PROMs and treated ASD. Sagittal parameters planned preoperatively correlated with postoperative correction. PJF was reduced, compared to the literature (35%), but PJK was observed over time. DJF occurred and was related to the absence of interbody cages at the lumbosacral junction and decisional regret., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-23-85/coif). G.M.M. has disclosures of Globus Medical (consultancy), Device Technologies (travel), LifeHealthcare (consultancy, travel), National Surgical (travel), and SeaSpine (travel). The other authors have no conflicts of interest to declare., (2023 Journal of Spine Surgery. All rights reserved.)

Background: Low bone mineral density (BMD) is a well-established risk factor for mechanical complications following adult spinal deformity (ASD) surgery. Hounsfield units (HU) measured on computed tomography (CT) scans are a proxy of BMD. In ASD surgery, we sought to: (I) evaluate the association of HU with mechanical complications and reoperation, and (II) identify optimal HU threshold to predict the occurrence of mechanical complications., Methods: A single-institution retrospective cohort study was undertaken for patients undergoing ASD surgery from 2013-2017. Inclusion criteria were: ≥5-level fusion, sagittal/coronal deformity, and 2-year follow-up. HU were measured on 3 axial slices of one vertebra, either at the upper instrumented vertebra (UIV) itself or UIV ±4 from CT scans. Multivariable regression controlled for age, body mass index (BMI), postoperative sagittal vertical axis (SVA), and postoperative pelvic-incidence lumbar-lordosis mismatch., Results: Of 145 patients undergoing ASD surgery, 121 (83.4%) had a preoperative CT from which HU were measured. Mean age was 64.4±10.7 years, mean total instrumented levels was 9.8±2.6, and mean HU was 153.5±52.8. Mean preoperative SVA and T1PA were 95.5±71.1 mm and 28.8°±12.8°, respectively. Postoperative SVA and T1PA significantly improved to 61.2±61.6 mm (P<0.001) and 23.0°±11.0° (P<0.001). Mechanical complications occurred in 74 (61.2%) patients, including 42 (34.7%) proximal junctional kyphosis (PJK), 3 (2.5%) distal junctional kyphosis (DJK), 9 (7.4%) implant failure, 48 (39.7%) rod fracture/pseudarthrosis, and 61 (52.2%) reoperations within 2 years. Univariate logistic regression showed a significant association between low HU and PJK [odds ratio (OR) =0.99; 95% confidence interval (CI): 0.98-0.99; P=0.023], but not on multivariable analysis. No association was found regarding other mechanical complications, overall reoperations, and reoperations due to PJK. HU below 163 were associated with increased PJK on receiver operating characteristic (ROC) curve analysis [area under the curve (AUC) =0.63; 95% CI: 0.53-0.73; P<0.001]., Conclusions: Though several factors contribute to PJK, it appears that 163 HU may serve as a preliminary threshold when planning ASD surgery to mitigate the risk of PJK., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-22-102/coif). SLZ serves as an unpaid editorial board member of Journal of Spine Surgery. SLZ reports being an unaffiliated neurotrauma consultant for the National Football League. BFS is a consultant for Nuvasive and Carbofix and receives institutional research support from Nuvasive and Stryker Spine. AMA received an institutional research support from Stryker Spine. The other authors have no conflicts of interest to declare., (2023 Journal of Spine Surgery. All rights reserved.)

Study Design: Prospective, multicenter, international observational study.Objective: To evaluate motor neurologic outcomes in patients undergoing surgery for complex adult spinal deformity (ASD).Summary Of Background Data: The neurologic outcomes after surgical correction for ASD have been reported with significant variability and have not been measured as a primary endpoint in any prospective, multicenter, observational study.Methods: The primary outcome measure was the change in American Spinal Injury Association (ASIA) Lower Extremity Motor Scores (LEMS) obtained preoperatively, and at hospital discharge, 6 weeks and 6 months postoperatively.Results: A total of 273 patients with complex ASD underwent surgery at 15 sites worldwide. One patient was excluded for lack of preoperative LEMS. The remaining 272 patients were divided into two groups: normal preoperative LEMS (=50) (Preop NML, N = 204, 75%) and abnormal preoperative LEMS (<50) (Preop ABNML, N = 68, 25%). At hospital discharge, 22.18% of patients showed a decline in LEMS compared with 12.78% who showed an improvement. At 6 weeks, there was a significant change compared with discharge: 17.91% patients showed a decline in LEMS and 16.42% showed an improvement. At 6 months, 10.82% patients showed a decline in preoperative LEMS, 20.52% improvement, and 68.66% maintenance. This was a significant change compared with 6 weeks and at discharge.Conclusion: Although complex ASD surgery can restore neurologic function in patients with a preoperative neurologic deficit, a significant portion of patients with ASD experienced postoperative decline in LEMS. Measures that can anticipate and reduce the risk of postoperative neurologic complications are warranted.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Background: The International Spine Study Group (ISSG) and the European Spine Study Group (ESSG) developed an adult spinal deformity (ASD) risk calculator based on one of the most granular, prospective ASD databases. The calculator utilizes preoperative radiographic, surgical, and patient-specific variables to predict patient-reported outcomes and complication rates at 2 years. Our aim was to assess the ISSG-ESSG risk calculator's usability in a single-institution ASD population., Methods: Frail ([F], 0.3 > 0.5) ASD patients were isolated in a single-center ASD database. Basic demographics were assessed via χ 2 and t tests. Each F patient was inputted into the ESSG risk calculator to identify individual predictive rates for postoperative 2-year health-related quality of life questions (HRQL) outcomes and major complications. These calculated predicted outcomes were analyzed against those identified from the ASD database in order to validate the calculator's predictability via Brier scores. A score closer to 1 meant the ISSG-ESSG calculator was not predictive of that specific outcome. A score closer to 0 meant the ISSG-ESSG calculator was a predictive tool for that factor., Results: A total of 631 ASD patients were isolated (55.8 ± 16.8 years, 26.68 kg/m 2 , 0.95 ± 1.3 Charlson Comorbidity Index). Of those patients, 7.8% were frail. Fifty percent of frail patients received an interbody fusion, 58.3% received a decompression, and 79.2% underwent osteotomy. Surgical details were as follows: mean operative time was 342.9 ± 94.3 minutes, mean estimated blood loss was 2131.82 ± 1011 mL, and average length of stay was 7.12 ± 2.5 days. The ISSG-ESSG calculator predicted the likelihood of improvement for the following HRQL's: Oswestry Disability Index (ODI) (86%), Scoliosis Research Society (SRS)-22 mental health (71.1%), SRS-22 total (87.6%), and major complication (53.4%). The single institution had lower percentages of improvement in ODI (24.6%), SRS-22 mental health (21.3%), SRS-22 total (25.1%), and lower presence of major complication (34.8%). The calculated Brier scores identified the calculator's predictability for each factor was as follows: ODI (0.24), SRS-22 mental health (0.21), SRS-22 total (0.25), and major complication (0.28)., Conclusions: All of the variables had low Brier scores, indicating that the ISSG-ESSG calculator can be used as a predictive tool for ASD frail patients., Competing Interests: Declaration of Conflicting Interests: The authors report no conflicts of interest in this work., (This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2022 ISASS. To see more or order reprints or permissions, see http://ijssurgery.com.)

Lateral lumbar interbody fusion (LLIF) is increasingly performed as corrective surgery for patients with adult spinal deformity (ASD). This paper compares the surgical results of LLIF and conventional posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) in ASD using a propensity score matching analysis. We retrospectively reviewed patients with ASD who received LLIF and PLIF/TLIF, and investigated patients' backgrounds, radiographic parameters, and complications. The propensity scores were calculated from patients' characteristics, including radiographic parameters and preoperative comorbidities, and one–to-one matching was performed. Propensity score matching produced 21 matched pairs of patients who underwent LLIF and PLIF/TLIF. All radiographic parameters significantly improved in both groups at the final follow-up compared with those of the preoperative period. The comparison between both groups demonstrated no significant difference in terms of postoperative pelvic tilt, lumbar lordosis (LL), or pelvic incidence–LL at the final follow-up. However, the sagittal vertical axis tended to be smaller in the LLIF at the final follow-up. Overall, perioperative and late complications were comparable in both procedures. However, LLIF procedures demonstrated significantly less intraoperative blood loss and a smaller incidence of postoperative epidural hematoma compared with PLIF/TLIF procedures in patients with ASD. [ABSTRACT FROM AUTHOR]

Adult spinal deformities (ASD) have a very high incidence of postoperative neurological decline. Spine surgeons all over the world are broadening the indications of endoscopic spine surgery (ESS) with similar/better outcomes to other conventional spine surgeries. In this report we present a case of L3-radiculopathy post ASD correction and its management with ESS. A 78-year-old female operated for ASD presented with backache, and right-side-dominant radiating leg pain. Imaging showed distal junctional failure with left rod fracture between L5-S1 and screw loosening with gross sagittal imbalance. She was treated with L4 pedicle subtraction osteotomy (PSO) with T10-iliac posterior fixation with use of satellite rods at PSO site. Post-operatively she developed left-sided L3 motor deficit. Imaging revealed left L3 root compression by bone fragment near the left L3 pedicle screw-head. We presume that, since the L3 pedicular screw had to be inserted deeper than the other screws to accommodate the satellite-rod, the bone in the area near the screw head (part of either the pedicle or facet) caused compression of the left L3 nerve root. The patient was treated with interlaminar ESS under awake anaesthesia and the compressing bone was drilled out. Post-operatively, patient had rapid relief of the radicular pain and improvement in the left quadriceps (L3) power with no recurrence at 1-year follow-up. Thus, post-operative iatrogenic neurological deficits can be treated successfully using ESS when the exact cause of the deficit is identified and is amenable to endoscopic removal. We could successfully treat a case of left-sided L3-radiculopathy, caused due to protruding bony spur after ASD correction surgery with ESS., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/acr-21-58). JB and SHL are consultants with Joimax GmbH. AHS has no conflicts of interest to declare., (2022 AME Case Reports. All rights reserved.)

Background: The decision upper-most instrumented vertebrae (UIV) in a multi-level fusion procedure can dramatically influence outcomes of corrective spine surgery. We aimed to create an algorithm for selection of UIV based on surgeon selection/reasoning of sample cases., Methods: The clinical/imaging data for 11 adult spinal deformity (ASD) patients were presented to 14 spine deformity surgeons who selected the UIV and provided reasons for avoidance of adjacent levels. The UIV chosen was grouped into either upper thoracic (UT, T1-T6), lower thoracic (LT, T7-T12), lumbar or cervical. Disagreement between surgeons was defined as ≥3 not agreeing. We performed a descriptive analysis of responses and created an algorithm for choosing UIV then applied this to a large database of ASD patients., Results: Surgeons agreed in 8/11 cases on regional choice of UIV. T10 was the most common UIV in the LT region (58%) and T3 was the most common UIV in the UT region (44%). The most common determinant of UIV in the UT region was proximal thoracic kyphosis and presence of coronal deformity. The most common determinant of UIV in the LT region was small proximal thoracic kyphosis. Within the ASD database (236 patients), when the algorithm called for UT fusion, patients fused to TL region were more likely to develop proximal junctional kyphosis (PJK) at 1 year post-operatively (76.9% vs . 38.9%, P=0.025)., Conclusions: Our algorithm for selection of UIV emphasizes the role of proximal and regional thoracic kyphosis. Failure to follow this consensus for UT fusion was associated with twice the rate of PJK., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jss-20-598). Dr. SB reports personal fees from K2M, from Medtronic, personal fees from Nuvasive, from Orthofix, personal fees from Stryker, outside the submitted work; Dr. DB reports grants from Bioventus, grants from Depuy, grants from Pfizer, grants from Progenerative Medical, outside the submitted work; Dr. PP reports other from Allosource, personal fees from Globus Medical, personal fees from Medicrea, personal fees from Royal Biologics, personal fees from SpineWave, personal fees from Terumo, personal fees from Zimmer, outside the submitted work; Dr. MG reports grants from Depuy, personal fees from Globus, grants from Innomed, personal fees from Johnson and Johnson, personal fees from Medtronic, other from Proctor and Gamble, personal fees from Wolters Kluwer Health, outside the submitted work; Dr. TP reports other from Altus, personal fees from Globus Medical, personal fees from Medicrea, personal fees from Nuvasive, other from Spine Align, personal fees from Stryker, other from Torus Medical, outside the submitted work; Dr. HJK reports personal fees from Alphatec, other from K2M, other from Zimmer, outside the submitted work; Dr. JSS reports other from Alphatec, personal fees from Carlsmed, personal fees from Cerapedics, grants from Depuy, other from Nuvasive, personal fees from Styker, other from Zimmer, outside the submitted work; Dr. RE reports personal fees from Aesculap, other from Alphatec, personal fees from Baxter, personal fees from Biederman-Motech, personal fees from Carevature, other from Globus, other from Invuity, personal fees from Medtronic, other from Nocimed, personal fees and other from Nuvasive, personal fees from Radius, other from Seaspine, personal fees and other from SI Bone, other from Spine Innovations, outside the submitted work; Dr. KK reports personal fees and other from Depuy, personal fees and other from Orthofix, other from Strykler, outside the submitted work; Dr. GM reports personal fees from Carlsmed, other from K2M, other from Nuvasive, personal fees from Seaspine, personal fees from Stryker, personal fees from Viseon, outside the submitted work; Dr. CS reports grants from Depuy, grants from Globus, grants and other from Medtronic, other from Nuvasive, other from SI Bone, outside the submitted work; Dr. JG reports grants and other from Accuity, other from Cingulate, personal fees from Depuy, grants from Integra, personal fees from Intellirod, personal fees from K2M, personal fees from Mazor, personal fees from Medtronic, grants from Norton Healthcare, other from Nuvasive, personal fees from Pfizer, personal fees from Stryker, outside the submitted work; Dr. VL reports personal fees from Depuy, personal fees from Globus, other from Nuvasive, personal fees from Permanante Medical Group, outside the submitted work; Dr. FS reports grants from Depuy, personal fees from Globus, from K2M, personal fees from Medicrea, grants, personal fees and other from Medtronic, grants from Nuvasive, grants from Styker, grants, personal fees and other from Zimmer, outside the submitted work. The other authors have no conflicts of interest to declare., (2021 Journal of Spine Surgery. All rights reserved.)

Background: This cross sectional study describes a "Soft Landing" strategy utilizing hooks for minimizing proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). The technique creates a gradual transition from a rigid segmental construct to unilateral hooks at the upper instrumented level and preservation of the soft tissue attachments on the contralateral side of the hooks. Authors devise a novel classification system for better grading of PJK severity., Methods: Thirty-nine consecutive adult spinal deformity (ASD) patients at a single institution received the "Soft Landing" technique. The proximal junctional angle was measured preoperatively and at last follow-up using standing 36-inch spinal radiographs. Changes in proximal junctional angle and rates of PJK and PJF were measured and used to create a novel classification system for evaluating and categorizing ASD patients postoperatively., Results: The mean age of the cohort was 61.4 years, and 90% of patients were women. Average follow up was 2.2 years. The mean change in proximal junctional angle was 8° (SD 7.4°) with the majority of patients (53%) experiencing less than 10° and only 1 patients with proximal junctional angle over 20°. Four patients (10%) needed additional surgery for proximal extension of the uppermost instrumented vertebra (UIV) secondary to PJF., Conclusions: Soft Landing technique is a possibly effective treatment strategy to prevent PJK and PJF following ASD that requires further evaluation. The described classification system provides management framework for better grading of PJK. The "Soft Landing" technique warrants further comparison to other techniques currently used to prevent both PJK and failure., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/jss-20-622). CS has stock ownership of Vertera Spine. VA is a paid consultant for Depuy, Zimmer, Nuvasive, Medtronic, and Camber. The other authors have no conflicts of interest to declare., (2021 Journal of Spine Surgery. All rights reserved.)

Operative management of adult spinal deformity (ASD) has been increasing in recent years secondary to an aging society. The advance of intraoperative image guidance, such as the development of navigation and robotics systems has contributed to the growth and safety of ASD surgery. Currently, intraoperative image guidance is mainly used for pedicle screw placement and the evaluation of alignment correction in ASD surgery. Though it is expected that the use of navigation and robotics would result in increasing pedicle screw accuracy as reported in other spine surgeries, there are no well-powered studies specifically focusing on ASD surgery. Currently, deformity correction relies heavily on preoperative planning, however, a few studies have shown the possibility that intraoperative image modalities may accurately predict postoperative spinopelvic parameters. Future developments of intraoperative image guidance are needed to overcome the remaining challenges in ASD surgery such as radiation exposure to patient and surgeon. More novel imaging modalities may result in evolution in ASD surgery. Overall there is a paucity of literature focusing on intraoperative image guidance in ASD surgery, therefore, further studies are warranted to assess the efficacy of intraoperative image guidance in ASD surgery. This narrative review sought to provide the current role and future perspectives of intraoperative image guidance focusing on ASD surgery., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-20-2765). The series “Current State of Intraoperative Imaging” was commissioned by the editorial office without any funding or sponsorship. RAL reports personal fees and other from Medtronic, personal fees and other from Stryker, outside the submitted work. The authors have no other conflicts of interest to declare., (2021 Annals of Translational Medicine. All rights reserved.)

Background: Adult spinal deformity (ASD) is a prevalent condition in individuals over the age of 65; leading to impaired standing balance and abnormal gait patterns. This functional impairment may be due to the fixed sagittal or coronal malalignment; associated spinal stenosis or deconditioning. The Berg balance scale (BBS) was developed to measure balance by assessing the performance of functional tasks. The purpose of this study is to determine if BBS is a useful metric for evaluating functional status in ASD patients., Methods: ASD patients who required fusion from the thoracic spine to the pelvis from 2014 to 2016 were enrolled and asked to complete the BBS prior to and six months after surgery. BBS were obtained by a certified physical therapist. Standard demographic; radiographic and surgical data were collected. The Oswestry disability index (ODI), EuroQOL-5D and numeric rating scales (0 to 10) for back and leg pain were assessed at baseline and post-intervention., Results: Of 21 patients enrolled; 19 completed pre- and post-surgery BBS. The mean age was 59.8±13.3 years with 14 females. There was a statistically significant improvement in all outcome scores and radiographic parameters after surgery; but no difference in BBS. Only one patient had a BBS score low enough to be considered a medium fall risk. There was no difference in the pre-op BBS scores in the four patients that had revision surgery compared to those that did not., Conclusions: In this small pilot study; BBS did not appear to be associated with measures of clinical and radiographic improvement in ASD patients. The test was also potentially problematic in that it has a ceiling effect and required significant time with a trained physical therapist for administration. Continued effort to identify a viable measure of balance dysfunction in ASD patients is warranted., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Spine Surgery. All rights reserved.)

Background: Surgical treatment for adult degenerative scoliosis (ADS) is a complex undertaking and is associated with a high complication rate. Our aim was to evaluate the clinical and radiological outcomes, mortality and morbidity of multilevel posterior lumbar interbody fusion (MPLIF) in the treatment in ADS based on the experience of a single tertiary referral center for spinal surgery., Methods: We performed a retrospective analysis of prospectively collected data of consecutive patients who had undergone multi-level posterior interbody fusion for degenerative scoliosis. We prospectively recorded patients' demographics, co-morbidities; coronal and sagittal plane deformity assessment and surgical details: number of instrumented levels, and intra-operative and postoperative complications. Functional outcomes and patient-reported complications were entered in our local spine surgery database (part of the Eurospine Spine Tango Registry) and used to collect data on functional scores and patient-reported complications preoperatively and at 6, 12 and 24 months' follow-up., Results: Our study involved 13 males and 51 females with a mean age of 70.26 (range 49-90, SD 8.9). MPLIF was performed at five levels in one patient, four levels in 29 patients, three levels in 20 patients, and two levels in 14 patients. There were a total of 14 (21.87%) major, minor and mechanical complications. There were no procedure-related mortalities. The average COMI and Eq5d scores improved significantly post-surgery, and this improvement was maintained at a mean follow-up of up to two years., Conclusions: Multilevel posterior interbody fusion is a safe procedure, and in selected cases can result in good clinical and radiological outcomes with improvement in patient quality of life., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Spine Surgery. All rights reserved.)

Background: The study is a retrospective review of a multi-institutional database, aiming to determine predictors of non-depressed, satisfied adult spinal deformity (ASD) patients with good self-image at 2-year follow-up (2Y). ASD significantly impacts a patients' psychological status. Following treatment, little is known about predictors of satisfied patients with high self-image and mental status., Methods: Inclusion: primary ASD pts >18 y/o with complete 2Y follow-up. Non-depressed [Short Form 36-mental component score (SF36-MCS) >42], satisfied patients (SRS22-satisfaction >3) with good self-image (SR22-self-image >3) at 2Y were isolated (happy). Happy and control patients were propensity-matched by baseline and 2Y leg pain, Charlson, frailty, and radiographic measures for the operative (OP) and non-operative cohorts (NOP). Health related quality of life (HRQL), surgical and radiographic metrics were compared. Regression models identified predictors of happy patients. Thresholds were calculated using area under the curve (AUC) and 95%CI., Results: Of 480 patients, 94 OP (happy: 47 vs. control: 47) and 92 NOP (46 each) reached inclusion. At baseline, groups had similar age, gender, Oswestry disability index (ODI) (OP: 39.13 vs. 37.49, NOP: 17.70 vs. 19.74) and SF36-physical component score (PCS) (OP: 33.51 vs. 35.04, NOP: 47.93 vs. 44.72). Despite similar (P>0.05) surgeries, length of stay (LOS), and radiographic outcomes between OP happy and control groups, happy had less peri-operative complications (31.9% vs. 57.4%, P=0.13), better 2Y ODI (17.77 vs. 29.98), SRS22 component, total, and SF36 scores (P<0.05). NOP happy patients also exhibited better 2Y ODI (13.24 vs. 22.09), SRS22 component, total, and SF36 scores (P<0.05). Baseline SRS-mental (OR: 2.199, AUC: 0.617, cutoff: 2.5) and ODI improvement (OR: 1.055, AUC: 0.717, cutoff: >12) predicted happy OP patients, while baseline SRS-self-image (OR: 5.195, AUC: 0.740, cutoff: 3.5) and ODI improvement (OR: 1.087, AUC: 0.683, cutoff: >9) predicted happy NOP patients., Conclusions: Baseline mental-status, self-image and ODI improvement significantly impact long-term happiness in ASD patients. Despite equivalent management and alignment outcomes, operative and non-operative happy patients had better 2Y disability scores. Management strategies aimed at improving baseline mental-status, perception-of-deformity, and maximizing ODI may optimize treatment outcomes., Competing Interests: Conflicts of Interest: E Klineberg (DePuy Synthes—consulting, Stryker—consulting, Springer—consulting, Trevana—consulting, AOSpine—honoraria, fellowship support, K2M—honoraria); V Lange (Nemaris—stock ownership, DePuy Synthes—teaching/speaking, Nuvasive—teaching/speaking, K2M—teaching/speaking, Medtronic—teaching/speaking, Nemaris—board of directors); F Schwab (Zimmer Biomet—speaking/teaching, consulting, royalties/patents, NuVasive—speaking/teaching, consulting, royalties/patents, K2M—speaking/teaching, consulting, royalties/patents, MSD—speaking/teaching, consulting, royalties/patents, Medicrea—speaking/teaching, consulting, Nemaris—board of directors, shareholder); PG Passias (Medicrea—consulting, SpineWave—consulting, Allosource—Scientific Advisory Board, Zimmer Biomet—teaching/speaking, Globus—teaching/speaking, CSRS—grant, Aesculap—research study). The other authors have no conflicts of interest to declare.

Background: This study aims to describe properties of adult spinal deformity (ASD) revisions relative to primary surgeries and determine clinical variables that can predict revision. ASD is a common pathology that can lead to decreased quality of life, pain, physical limitations, and dissatisfaction with self-image. Durability of interventions for deformity treatment is of paramount concern to surgeons, as revision rates remain high., Methods: Patients undergoing thoracolumbar fusion, five or more levels, for scoliosis (primary diagnosis ICD-9 737.x) were identified on a state-wide database. Primary and revision (returning for re-fusion procedure) surgeries were compared based on demographic, hospital stay, and clinical characteristics. Differences between primary and revision surgeries, and predictors of primary surgeries requiring revision, utilized binary logistic regression controlling for age, comorbidity burden, and levels fused., Results: A total of 1,063 patients (average 7.4 levels fused, mean age: 47.6 years, 69.0% female) undergoing operative treatment for ASD were identified, of which 123 (average 7.1 levels fused, 11.6%, mean age 61.43, 80.5% female) had surgical revision. Primary surgeries were ~0.3 levels longer (P=0.013), used interbody ~11% more frequently (P=0.020), and used BMP ~12% less frequently (P=0.008). Revisions occurred 176.4 days after the primary on average. The most frequent causes of revisions were: 43.09% implant failure, 24.39% acquired kyphosis, and 14.63% enduring scoliosis. After controlling for age, comorbidities, and levels fused older, more comorbid, female, and white-race patients were more likely to be revised. Upon multivariate regression, after controlling for age and levels fused, overall complications remained non-different (OR: 0.8, 95% CI: 0.6-1.2). However, revision remained an independent predictor for infection (OR: 5.5, 95% CI: 2.8-10.5)., Conclusions: In a statewide database with individual patient follow up of up to 4 years 10% of ASD patients undergoing scoliosis correction required revision. Revision surgeries had higher infection incidence., Competing Interests: Conflicts of Interest: Dr. PG Passias discloses consulting agreements with Medicrea, Zimmer Biomet, and Spinewave, as well as scientific advisory board membership with Allosource. The other authors have no conflicts of interest to declare.

Background: To identify predictive factors for critical care unit-level complications (CCU complication) after long-segment fusion procedures for adult spinal deformity (ASD)., Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database [2010-2014] was reviewed. Only adult patients who underwent fusion of 7 or more spinal levels for ASD were included. CCU complications included intraoperative arrest/infarction, ventilation >48 hours, pulmonary embolism, renal failure requiring dialysis, cardiac arrest, myocardial infarction, unplanned intubation, septic shock, stroke, coma, or new neurological deficit. A stepwise multivariate regression was used to identify independent predictors of CCU complications., Results: Among 826 patients, the rate of CCU complications was 6.4%. On multivariate regression analysis, dependent functional status (P=0.004), combined approach (P=0.023), age (P=0.044), diabetes (P=0.048), and surgery for over 8 hours (P=0.080) were significantly associated with complication development. A simple scoring system was developed to predict complications with 0 points for patients aged <50, 1 point for patients between 50-70, 2 points for patients 70 or over, 1 point for diabetes, 2 points dependent functional status, 1 point for combined approach, and 1 point for surgery over 8 hours. The rate of CCU complications was 0.7%, 3.2%, 9.0%, and 12.6% for patients with 0, 1, 2, and 3+ points, respectively (P<0.001)., Conclusions: The findings in this study suggest that older patients, patients with diabetes, patients who depend on others for activities of daily living, and patients who undergo combined approaches or surgery for over 8 hours may be at a significantly increased risk of developing a CCU-level complication after ASD surgery., Competing Interests: Conflicts of Interest: The abstract of this manuscript was presented as an electronic poster in Congress of Neurological Surgeon’s Annual Meeting 2017 in Boston Massachusetts, October 7–11, 2017.

Objective: Minimally invasive spinal surgery (MISS) has many favorable attributes that would be of great benefit to patients with an adult spinal deformity. Decreased blood loss, lower infection rates, and faster mobilization may help to reduce the high rate of complications associated with these interventions. Although correction of coronal deformity has been well demonstrated with MISS, improvements in lordosis and sagittal balance have remained relatively elusive using the MISS approach. With open surgery, the most powerful techniques for improving sagittal balance include some form of a spinal osteotomy. Methods: In this report, we describe the evolution of a technique for treating thoracolumbar kyphoscoliosis using a mini-open pedicle subtraction osteotomy (PSO) combined with interbody fusion and percutaneous pedicle screws. Results: The patient underwent a T10 to S1 percutaneous posterior instrumented with an L3 PSO and right L4/5 minimally invasive transforaminal interbody fusion. Clinically, the patient had excellent improvement and regained the ability to ambulate independently for distances of up to one half mile. Imaging demonstrated good correction of coronal imbalance (1.8 to 9.5 cm) and sagittal imbalance (sagittal vertical axis of 22.5 to 7 cm). Conclusions: The correction of sagittal plane deformities remains difficult using MISS approaches. In this report, we describe a new technique using a mini-open PSO technique to achieve significant improvement in thoracolumbar lordosis. [Copyright &y& Elsevier]