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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: Modified Delphi study., Objective: Adult spinal deformity (ASD) is an increasingly recognized condition, comprising a spectrum of pathologies considerably impacting patients' health and functional status. Patients present with a combination of pain, disability, comorbidities and radiological deformity. The study aims to propose a systematic approach of gathering information on the factors that drive decision-making by developing a patient profile., Methods: The present study comprises of 3 parts. Part 1: Development of prototype of patient profile: The data from the Core Outcome Study on SCOlisis (COSSCO) by Scoliosis Research Society (SRS) was categorized into a conceptual framework. Part 2: Modified Delphi study: Items reaching >70% agreement were included in a 4 round iterative process with 51 panellists across the globe. Part 3: Pilot testing-feasibility: Content validity and usability were evaluated quantitatively., Results: The profile consisted of 4 domains. 1. General health with demographics and comorbidities, 2.Spine-specific health with spine related health and neurological status, 3. Imaging with radiographic and MRI parameters and 4. Deformity type . Each domain consisted of 1 or 2 components with various factors and their measuring instruments. Profile was found to have an excellent content validity (I-CVI r 0.78-1.00; Ave-CVI 0.92) appropriateness, relevance and usefulness., Conclusions: The present study, is first to provide a universally applicable multimodal ASD patient profile to methodically describe patients. Physicians are encouraged to assess ASD patients holistically using this profile and not just based on radiographic findings.

Purpose: This study sought to investigate associations between upper instrumented vertebra (UIV) location and the risk of proximal junctional kyphosis (PJK) at 2 years following posterior spinal fusion (PSF) for Scheuermann's kyphosis (SK)., Methods: In this retrospective cohort study, SK patients who underwent PSF and reached 2 years postop were identified in a multicenter international registry, excluding those with anterior release, prior spine surgery, neuromuscular comorbidity, post-traumatic kyphosis, or kyphosis apex below T11-T12. Location of UIV as well as the number of levels between UIV and preoperative kyphosis apex was determined. Additionally, the degree of kyphosis correction was evaluated. PJK was defined as a proximal junctional angle ≥ 10° that is ≥ 10° greater than the preoperative measurement., Results: 90 patients (16.5 ± 1.9 yo, 65.6% male) were included. Preoperative and 2-year postoperative major kyphosis was 74.6 ± 11.6° and 45.9 ± 10.5°, respectively. Twenty-two (24.4%) patients developed PJK at 2 years. Patients with UIV below T2 had a 2.09 times increased risk of PJK when compared to those with UIV at or above T2, adjusting for distance between UIV and preoperative kyphosis apex [95% Confidence Interval (CI) 0.94; 4.63, p = 0.070]. Patients with UIV ≤ 4.5 vertebrae from the apex had a 1.57 times increased risk of PJK, adjusting for UIV relative to T2 [95% CI 0.64; 3.87, p = 0.326]., Conclusion: SK patients with UIV below T2 had an increased risk of developing PJK at 2 years following PSF. This association supports consideration of UIV location during preoperative planning., Level of Evidence: Prognostic Level II., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

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: The aim of this study was to discern whether patients with a cranial sagittal vertical axis to the hip (CrSVA-H) > 2 cm at 2 years postoperatively exhibit significantly worse patient-reported outcomes (PROs) and clinical outcomes compared with patients with CrSVA-H < 2 cm., Methods: This was a retrospective, 1:1 propensity score-matched (PSM) study of patients who underwent posterior spinal fusion for adult spinal deformity. All patients had a baseline sagittal imbalance of CrSVA-H > 30 mm. Two-year patient-reported and clinical outcomes were assessed in unmatched and PSM cohorts, including Scoliosis Research Society-22r (SRS-22r) and Oswestry Disability Index scores as well as reoperation rates. The study compared two cohorts based on 2-year alignment: CrSVA-H < 20 mm (aligned cohort) vs CrSVA-H > 20 mm (malaligned cohort). For the matched cohorts, binary outcome comparisons were carried out using the McNemar test, while continuous outcomes used the Wilcoxon rank-sum test. For unmatched cohorts, categorical variables were compared using chi-square/Fisher's tests, while continuous outcomes were compared using Welch's t-test., Results: A total of 156 patients with mean age of 63.7 (SEM 1.09) years underwent posterior spinal fusion spanning a mean of 13.5 (0.32) levels. At baseline, the mean pelvic incidence minus lumbar lordosis mismatch was 19.1° (2.01°), the T1 pelvic angle was 26.6° (1.20°), and the CrSVA-H was 74.9 (4.33) mm. The mean CrSVA-H improved from 74.9 mm to 29.2 mm (p < 0.0001). At the 2-year follow-up, 129 (78%) of 164 patients achieved CrSVA-H < 2 cm (aligned cohort). Patients who had CrSVA-H > 2 cm (malaligned cohort) at the 2-year follow-up had worse preoperative CrSVA-H (p < 0.0001). After performing PSM, 27 matched pairs were generated. In the PSM cohort, the aligned and malaligned cohorts demonstrated comparable preoperative patient-reported outcomes (PROs). However, at the 2-year postoperative follow-up, the malaligned cohort reported worse outcomes in SRS-22r function (p = 0.0275), pain (p = 0.0012), and mean total score (p = 0.0109). Moreover, when patients were stratified based on their magnitude of improvement in CrSVA-H (< 50% vs > 50%), patients with > 50% improvement in CrSVA-H had superior outcomes in SRS-22r function (p = 0.0336), pain (p = 0.0446), and mean total score (p = 0.0416). Finally, patients in the malaligned cohort had a higher 2-year reoperation rate (22% vs 7%; p = 0.0412) compared with patients in the aligned cohort., Conclusions: Among patients who present with forward sagittal imbalance (CrSVA-H > 30 mm), patients with CrSVA-H exceeding 20 mm at the 2-year postoperative follow-up have inferior PROs and higher reoperation rates.

Study Design: Prospective, cross-sectional cohort study., Objective: To determine the relationship between lumbar shape and sagittal parameters., Summary of Background Data: Understanding the lumbar shape is vital for deformity surgery. Normative sagittal parameters and spine shape remain unstudied in large, multiethnic, asymptomatic cohorts., Materials and Methods: A prospective, cross-sectional cohort of 468 asymptomatic volunteers between 18 and 80 years was enrolled across 5 countries. Demographic data and radiographic parameters such as pelvic incidence (PI) were collected. Pearson correlation test and linear regression were used to find the relationship between lumbar lordosis (LL) and other parameters. One-way analysis of variance and Welch 2-sample t test were performed to compare lumbar shape across such categories as PI and lumbar apex followed by post hoc Bonferroni correction if needed., Results: PI was moderately correlated with proximal lumbar lordosis (pLL) ( r = -0.54) and weakly correlated with distal lumbar lordosis (dLL) ( r = -0.16). Thoracic kyphosis (T1-T12) was moderately correlated with pLL ( r = -0.35) and dLL ( r = -0.29). dLL was moderately correlated with LL ( r = 0.64). 2.6% (12/468) of subjects had lumbar apex at L2, 40.2% (188/468) at L3, 56.6% at L4 (265/468), and 0.6% (3/468) at other levels. Mean PI was different between volunteers with the apex at L3 and L4. A lower mean PI was associated with the apex at L4 (49.0°), whereas a higher mean PI was associated with the apex at L3 (55.8°). The mean PI-LL mismatch for volunteers was -5.4° with a range from -35° to 39.7°. PI-LL mismatch increased from a mean of -10.1° in volunteers with low PI to a mean of 2.2° in volunteers with high PI. Age was not correlated with LL ( P = 0.84)., Conclusions: In asymptomatic adult volunteers, pLL showed a moderate correlation with PI and increased with PI, whereas dLL showed a weak correlation. The lumbar apex migrated proximally with increasing PI. Segmental lordosis and apex position instead of solely global lordosis should be emphasized., Level of Evidence: Level III., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Multi-center, prospective, observational cohort., Objective: To compare myelopathic vs. non-myelopathic ambulatory patients in short- and long-term neurologic function, operative treatment, and patient-reported outcomes., Methods: Pediatric deformity patients from 16 centers were enrolled with the following inclusion criteria: aged 10-21 years-old, a Cobb angle ≥100° in either the coronal or sagittal plane or any sized deformity with a planned 3-column osteotomy, and community ambulators. Patients were dichotomized into 2 groups: myelopathic (abnormal preoperative neurologic exam with signs/symptoms of myelopathy) and non-myelopathic (no clinical signs/symptoms of myelopathy)., Results: Of 311 patients with an average age of 14.7 ± 2.8 years, 29 (9.3%) were myelopathic and 282 (90.7%) were non-myelopathic. There was no difference in age ( P = 0.18), gender ( P = 0.09), and Risser Stage ( P = 0.06), while more patients in the non-myelopathic group had previous surgery (16.1% vs. 3.9%; P = 0.03). Mean lower extremity motor score (LEMS) in myelopathic patients increased significantly compared to baseline at every postoperative visit: Baseline: 40.7 ± 9.9; Immediate postop: 46.0 ± 7.1, P = 0.02; 1-year: 48.2 ± 3.7, P < 0.001; 2-year: 48.2 ± 7.7, P < 0.001). The non-myelopathic group had significantly higher LEMS immediately postoperative ( P = 0.0007), but by 1-year postoperative, there was no difference in LEMS between groups (non-myelopathic: 49.3 ± 3.6, myelopathic: 48.2 ± 3.7, P = 0.10) and was maintained at 2-years postoperative (non-myelopathic: 49.2 ± 3.3, myelopathic: 48.2 ± 5.7, P = 0.09). Both groups improved significantly in all SRS domains compared to preoperative, with no difference in scores in the domains for pain ( P = 0.12), self-image ( P = 0.08), and satisfaction ( P = 0.83) at latest follow-up., Conclusion: In severe spinal deformity pediatric patients presenting with preoperative myelopathy undergoing spinal reconstructive surgery, myelopathic patients can expect significant improvement in neurologic function postoperatively. At 1-year and 2-year postoperative, neurologic function was no different between groups. While non-myelopathic patients had significantly higher postoperative outcomes in SRS mental-health, function, and total-score, both groups had significantly improved outcomes in every SRS domain compared to preoperative.

Background: We aimed to propose the apical vertebras distribution modifier to supplement the coronal balance (CB) classification for adult idiopathic scoliosis (AdIS). An algorithm to predict postoperative coronal compensation and avoid postoperative coronal imbalance (CIB) was proposed. Methods: Patients were categorized into CB and CIB groups according to the preoperative coronal balance distance (CBD). The apical vertebras distribution modifier was defined as negative (-) if the centers of the apical vertebras (CoAVs) were on either side of the central sacral vertical line (CSVL) and positive (+) if the CoAVs were on the same side of the CSVL. Results: A total of 80 AdIS patients, with an average age of 25.97 ± 9.20 years, who underwent posterior spinal fusion (PSF) were prospectively recruited. The mean Cobb angle of the main curve was 107.25 ± 21.11 degrees at preoperation. The mean follow-up time was 3.76 ± 1.38 (2-8) years. At postoperation and follow-up, CIB occurred in 7 (70%) and 4 (40%) CB- patients, 23 (50%) and 13 (28.26%) CB+ patients, 6 (60%) and 6 (60%) CIB- patients, and 9 (64.29%) and 10 (71.43%) CIB+ patients. Health-related quality of life (HRQoL) was significantly better in the CIB- group compared with that of the CIB+ group in the dimension of back pain. To avoid postoperative CIB, the correction rate of the main curve (CRMC) should match the compensatory curve for CB-/+ patients; the CRMC should be greater than the compensatory curve for CIB- patients; and the CRMC should be less than the compensatory curve for CIB+ patients, and the inclination of the LIV needs to be reduced. Conclusions: CB+ patients have the least postoperative CIB rate and the best coronal compensatory ability. CIB+ patients are at a high risk of postoperative CIB and have the poorest coronal compensatory capacity in the event of postoperative CIB. The proposed surgical algorithm facilitates the handling of each type of coronal alignment.

Study Design: Retrospective cohort., Objective: To examine SRS-Self Image scores at up to 10 years after surgery for adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Self-image is complex with implications for surgical and patient-reported outcomes after AIS surgery. Surgically modifiable factors that impact self-image are inconsistently reported in the literature with few longer-term reports. We examined the rate and durability of self-image improvement., Materials and Methods: An AIS registry was queried for patients with up to 10 years of follow-up after AIS surgery. A mixed effects model estimated change in SRS-22 Self Image from baseline to 6 weeks, 1 year, 2 years, 5 years, and 10 years. All enrolled patients contributed data to the mixed effects models. A sub-analysis of patients with 1-year and 10-year follow-up evaluated worsening/static/improved SRS-22 Self Image scores examined stability of scores over that timeline. Baseline demographic data and 1-year deformity magnitude data were compared between groups using parametric and nonparametric tests as appropriate., Results: Data from 4608 patients contributed data to the longitudinal model; 162 had 1-year and 10-year data. Mean SRS-Self Image improvement at 10-year follow-up was 1.0 (95% CI: 0.9-1.1) point. No significant changes in Self-Image domain scores were estimated from 1-year to 10-year (all P >0.05) postoperative. Forty (25%) patients had SRS-Self Image worsening from 1 year to 10 years, 36 (22%) improved, and 86 (53%) were unchanged. Patients who worsened over 10 years had lower SRS-Self Image at baseline than those unchanged at enrollment (3.3 vs. 3.7, P =0.007). Neither radiographic parameters nor SRS-Mental Health were different at baseline for the enrolled patients., Conclusion: Ten years after surgery, 75% of patients reported similar or better SRS-Self Image scores than one year after surgery. Nearly 25% of patients reported worsening self-image at 10 years. Patients who worsened had lower baseline SRS-Self Image scores, without radiographic or mental health differences at baseline or follow-up., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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.

Objective: The objective was to describe an intraoperative method that accurately predicts postoperative coronal alignment for up to 2 years of follow-up. The authors hypothesized that the intraoperative coronal target for adult spinal deformity (ASD) surgery should account for lower-extremity parameters, including pelvic obliquity (PO), leg length discrepancy (LLD), lower-extremity mechanical axis difference (MAD), and asymmetrical knee bending., Methods: Two lines were drawn on intraoperative prone radiographs: the central sacral pelvic line (CSPL) (the line bisecting the sacrum and perpendicular to the line touching the acetabular sourcil of both hips) and the intraoperative central sacral vertical line (iCSVL) (which is drawn relative to CSPL based on the preoperative erect PO). The distance from the C7 spinous process to CSPL (C7-CSPL) and the distance from the C7 spinous process to iCSVL (iCVA) were compared with immediate and 2-year postoperative CVA. To account for LLD and preoperative lower-extremity compensation, patients were categorized into four preoperative groups: type 1, no LLD (< 1 cm) and no lower-extremity compensation; type 2, no LLD with lower-extremity compensation (PO > 1°, asymmetrical knee bending, and MAD > 2°); type 3, LLD and no lower-extremity compensation; and type 4, LLD with lower-extremity compensation (asymmetrical knee bending and MAD > 4°). A retrospective review of a consecutively collected cohort with ASD who underwent minimum 6-level fusion with pelvic fixation was performed for validation., Results: In total, 108 patients (mean ± SD age 57.7 ± 13.7 years, 14.0 ± 3.9 levels fused) were reviewed. Mean preoperative/2-year postoperative CVA was 5.0 ± 2.0/2.2 ± 1.8 cm. For patients with type 1, both C7-CSPL and iCVA had similar error margins for immediate postoperative CVA (0.5 ± 0.6 vs 0.5 ± 0.6 cm, p = 0.900) and 2-year postoperative CVA (0.3 ± 0.4 vs 0.4 ± 0.5 cm, p = 0.185). For patients with type 2, C7-CSPL was more accurate for immediate postoperative CVA (0.8 ± 1.2 vs 1.7 ± 1.8 cm, p = 0.006) and 2-year postoperative CVA (0.7 ± 1.1 vs 2.1 ± 2.2 cm, p < 0.001). For patients with type 3, iCVA was more accurate for immediate postoperative CVA (0.3 ± 0.4 vs 1.7 ± 0.8 cm, p < 0.001) and 2-year postoperative CVA (0.3 ± 0.2 vs 1.9 ± 0.8 cm, p < 0.001). For patients with type 4, iCVA was more accurate for immediate postoperative CVA (0.6 ± 0.7 vs 3.0 ± 1.3 cm, p < 0.001) and 2-year postoperative CVA (0.5 ± 0.6 vs 3.0 ± 1.6 cm, p < 0.001)., Conclusions: This system, which accounted for lower-extremity factors, provided an intraoperative guide to determine both immediate and 2-year postoperative CVA with high accuracy. For patients with type 1 and 2 (no LLD, with or without lower-extremity compensation), C7-intraoperative CSPL accurately predicted postoperative CVA up to 2-year follow-up (mean error 0.5 cm). For patients with type 3 and 4 (LLD, with or without lower-extremity compensation), iCVA accurately predicted postoperative CVA up to 2-year follow-up (mean error 0.4 cm).

Objective: Evaluate clinical improvement as measured by patient-reported outcomes (PROs) during the 1 to 2-year interval., Study Design: Retrospective Cohort., Methods: A single-institution registry of ASD patients undergoing surgery was queried for patients with ≥6 level fusions. Demographics and radiographic variables were collected. PROs collected were the ODI and SRS-22r scores at: preoperative, 1-year and 2-years. Outcome measures of clinical improvement during the 1-2 year time interval were: 1) group medians, 2) percent minimum clinically important difference (MCID), and 3) percent minimal symptom scale (MSS)(ODI < 20 or SRS-pain + function >8). Wilcoxon rank-sum tests, chi-squared tests, Kruskal-Wallis tests, and logistic regression were performed., Results: 157 patients undergoing ASD surgery with minimum of 1-year follow-up were included. Mean age was 53.2 and mean instrumented levels was 13.1. Preoperative alignment was: Neutral Alignment (NA) 49%, Coronal Malalignment (CM) 17%, Sagittal Malalignment (SM 17%), and Combined Coronal/Sagittal Malalignment (CCSM) 18%. Preoperative to 1-year, and preoperative to 2-years, all ODI/SRS-22r significantly improved ( P < .001). In all patients, the only significant improvement in PROs between 1-and 2-year postoperative were those reaching ODI MCID (69% 1-year vs. 84% 2-years; P < .001). Subgroup analysis: ≥55 years had an improved median ODI (18 vs. 8; P = .047) and an improved percent achieving ODI MCID (73% vs. 84%, P = .048). CCSM patients experienced significant improvement in SRS-appearance score (75% vs. 100%; P = .050), along with those with severe preoperative SM >7.5 cm (73% vs. 100%; P = .032)., Conclusions: Most ASD patients experience the majority of PRO improvement by 1-year postoperative. However, subsets of patients that may continue to improve up to 2-years postoperative include patients ≥55 years, combined coronal/sagittal malalignment, and those with severe sagittal malalignment ≥7.5 cm.

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

Purpose: (1) To describe the use of multi-rod constructs (MRCs) in adult spinal deformity (ASD) surgery, (2) to report rod fractures occurring at MRC sites, and (3) to evaluate risk factors for rod fractures., Methods: A single-center, retrospective cohort study was conducted of patients undergoing ASD surgery with these inclusion criteria: minimum 2-year follow-up, MRCs used, ≥ 10-level fusion, and fused to sacrum/pelvis. The primary outcome was rod fracture. Univariate/multivariate logistic regression was performed controlling for age, kickstand rod usage, number of rods across the lumbosacral junction (LSJ), and the amount of coronal/sagittal Cobb correction., Results: Among 57 patients undergoing ASD surgery with MRCs, mean age was 60 ± 11 years. With respect to MRCs, 32 (56%) patients had 3 rods, 18 (32%) had 4, and 7 (12%) had 5. Rods crossing the LSJ were most often three (63%), followed by four (25%) and five (5%) rods. Nine (16%) patients experienced rod fractures with eight (89%) patients having no more than three rods crossing the LSJ. A coronal correction > 30 mm was more often seen in patients with rod fracture (p = 0.030), while an SVA correction > 50 mm was not significantly different (p = 0.608). Multivariate logistic regression revealed that the amount of coronal correction was significantly associated with rod fracture (OR 1.03, 95% CI 1.01-1.07, p = 0.044), as was achieving a coronal correction > 30 mm (OR 7.72, 95% CI 1.17-51.10, p = 0.034), with no association between the amount of sagittal correction obtained and rod fracture., Conclusion: This study found that greater coronal correction was associated with an increased odds of rod fracture. We suggest adding at least four rods across the LSJ cephalad to the interbody fusions to avoid rod fractures in these high demand areas., Level of Evidence: III., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: Delphi method., Objective: To gain consensus on the following questions: (1) When should anticoagulation/antiplatelet (AC/AP) medication be stopped before elective spine surgery?; (2) When should AC/AP medication be restarted after elective spine surgery?; (3) When, how, and in whom should venous thromboembolism (VTE) chemoprophylaxis be started after elective spinal surgery?, Summary of Background Data: VTE can lead to significant morbidity after adult spine surgery, yet postoperative VTE prophylaxis practices vary considerably. The management of preoperative AC/AP medication is similarly heterogeneous., Materials and Methods: Delphi method of consensus development consisting of three rounds (January 26, 2021, to June 21, 2021)., Results: Twenty-one spine surgeons were invited, and 20 surgeons completed all rounds of questioning. Consensus (>70% agreement) was achieved in 26/27 items. Group consensus stated that preoperative Direct Oral Anticoagulants should be stopped two days before surgery, warfarin stopped five days before surgery, and all remaining AC/AP medication and aspirin should be stopped seven days before surgery. For restarting AC/AP medication postoperatively, consensus was achieved for low-risk/medium-risk/high-risk patients in 5/5 risk factors (VTE history/cardiac/ambulation status/anterior approach/operation). The low/medium/high thresholds were POD7/POD5/POD2, respectively. For VTE chemoprophylaxis, consensus was achieved for low-risk/medium-risk/high-risk patients in 12/13 risk factors (age/BMI/VTE history/cardiac/cancer/hormone therapy/operation/anterior approach/staged separate days/staged same days/operative time/transfusion). The one area that did not gain consensus was same-day staged surgery. The low-threshold/medium-threshold/high-threshold ranges were postoperative day 5 (POD5) or none/POD3-4/POD1-2, respectively. Additional VTE chemoprophylaxis considerations that gained consensus were POD1 defined as the morning after surgery regardless of operating finishing time, enoxaparin as the medication of choice, and standardized, rather than weight-based, dose given once per day., Conclusions: In the first known Delphi study to address anticoagulation/antiplatelet recommendations for elective spine surgery (preoperatively and postoperatively); our Delphi consensus recommendations from 20 spine surgeons achieved consensus on 26/27 items. These results will potentially help standardize the management of preoperative AC/AP medication and VTE chemoprophylaxis after adult elective spine surgery., Competing Interests: J.M.B.: Royalties; Globus Medical, Inc.; Stryker, Inc.; and Wolter Kluwer. The remaining 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.

Study Design: Retrospective cohort study., Objectives: The objectives were to: (1) characterize the changes in coronal vertical axis (CVA) after adult spinal deformity (ASD) surgery from immediate postoperative to 2-years postoperative, and (2) assess for predictors of CVA change from immediate postoperative to 2-years postoperative., Summary of Background Data: It is unknown whether coronal correction obtained immediately postoperative accurately reflects long-term coronal alignment., Materials and Methods: A retrospective, single-institution registry was queried for patients undergoing ASD surgery from 2015-2019, including patients undergoing ≥6-level fusions with preoperative coronal malalignment (CM), defined as CVA≥3 cm. A clinically significant change in CVA was defined a priori as ≥1 cm. Radiographic variables were obtained preoperatively, immediately postoperative, and at 2-years postoperative., Results: Of 368 patients undergoing ASD surgery, 124 (33.7%) had preoperative CM, and 64 (17.0%) completed 2-years follow-up. Among 64 patients, mean age was 53.6±15.4 years. Preoperatively, absolute mean CVA was 5.4±3.1 cm, which improved to 2.3±2.0 cm ( P <0.001) immediately postoperative and 2.2±1.6 cm ( P <0.001) at 2-years. The mean change in CVA from preoperative to immediately postoperative was 2.2±1.9 cm (0.3-14.4). During the immediate postoperative to 2-years interval, 29/64 (45.3%) patients experienced a significant change of CVA by ≥1 cm, of which 22/29 (76%) improved by a mean of 1.7 cm and 7/29 (24%) worsened by a mean of 3.5 cm. No preoperative or surgical factors were associated with changed CVA from immediately postoperative to 2-years., Conclusion: Among 64 patients undergoing ASD surgery with preoperative CM, 45.3% experienced a significant (≥1 cm) change in their CVA from immediately postoperative to 2-years postoperative. Of these 29 patients, 22/29 (76%) improved, whereas 7/29 (24%) worsened. Although no factors were associated with undergoing a change in CVA, this information is useful in understanding the evolution and spontaneous coronal alignment changes that take place after major ASD coronal plane correction., Competing Interests: R.A.L.: paid consultant for a company or supplier: Medtronic; other support: contracted research with the Department of Defense. L.G.L.: royalties from a company or supplier: Medtronic; paid consultant for a company or supplier: Medtronic, Acuity Surgical; Medical/Orthopaedic publications editorial/governing board: Deputy Editor of Spine Deformity; Reviewer for Spine , The Spine Journal , European Spine Journal , JBJS , Global Spine Journal ; Other support: International Spine Study Group, Harms Study Group, AO Spine Deformity Knowledge Forum. The remaining authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective study of data collected prospectively., Objective: The goal of this study is to create a predictive model of preoperative bone health status in adult patients undergoing adult spinal reconstructive (ASR) surgery using machine learning (ML)., Summary of Background Data: Despite understanding that bone health impacts spine surgery outcomes, spine surgeons lack the tools to risk stratify patients preoperatively to determine who should undergo bone health screening. An ML approach mines patterns in data to determine the risk for poor bone health in ASR patients., Materials and Methods: Two hundred and eleven subjects over the age of 30 with dual energy X-ray absorptiometry scans, who underwent spinal reconstructive surgery were reviewed. Data was collected by manual and automated collection from the electronic health records. The Weka software was used to develop predictive models for multiclass classification of healthy, osteopenia, and osteoporosis (OPO) bone status. Bone status was labeled according to the World Health Organization (WHO) criteria using dual energy X-ray absorptiometry T scores. The accuracy, sensitivity, specificity, and area under the receiver operating curve (AUC) were calculated. The model was evaluated on a test set of unseen data for generalizability., Results: The prevalence of OPO was 23.22% and osteopenia was 52.61%. The random forest model achieved optimal performance with an average sensitivity of 0.81, specificity of 0.95, and AUC of 0.96 on the training set. The model yielded an averaged sensitivity of 0.64, specificity of 0.78, and AUC of 0.69 on the test set. The model was best at predicting OPO in patients. Numerous patient features exhibited predictive value, such as body mass index, insurance type, serum sodium level, serum creatinine level, history of bariatric surgery, and the use of medications such as selective serotonin reuptake inhibitors., Conclusion: Predicting bone health status in ASR patients is possible with an ML approach. Additionally, data mining using ML can find unrecognized risk factors for bone health in ASR surgery patients., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: A post hoc analysis., Objective: Advances in machine learning (ML) have led to tools offering individualized outcome predictions for adult spinal deformity (ASD). Our objective is to examine the properties of these ASD models in a cohort of adult symptomatic lumbar scoliosis (ASLS) patients., Summary of Background Data: ML algorithms produce patient-specific probabilities of outcomes, including major complication (MC), reoperation (RO), and readmission (RA) in ASD. External validation of these models is needed., Methods: Thirty-nine predictive factors (12 demographic, 9 radiographic, 4 health-related quality of life, 14 surgical) were retrieved and entered into web-based prediction models for MC, unplanned RO, and hospital RA. Calculated probabilities were compared with actual event rates. Discrimination and calibration were analyzed using receiver operative characteristic area under the curve (where 0.5=chance, 1=perfect) and calibration curves (Brier scores, where 0.25=chance, 0=perfect). Ninety-five percent confidence intervals are reported., Results: A total of 169 of 187 (90%) surgical patients completed 2-year follow up. The observed rate of MCs was 41.4% with model predictions ranging from 13% to 68% (mean: 38.7%). RO was 20.7% with model predictions ranging from 9% to 54% (mean: 30.1%). Hospital RA was 17.2% with model predictions ranging from 13% to 50% (mean: 28.5%). Model classification for all three outcome measures was better than chance for all [area under the curve=MC 0.6 (0.5-0.7), RA 0.6 (0.5-0.7), RO 0.6 (0.5-0.7)]. Calibration was better than chance for all, though best for RA and RO (Brier Score=MC 0.22, RA 0.16, RO 0.17)., Conclusions: ASD prediction models for MC, RA, and RO performed better than chance in a cohort of adult lumbar scoliosis patients, though the homogeneity of ASLS affected calibration and accuracy. Optimization of models require samples with the breadth of outcomes (0%-100%), supporting the need for continued data collection as personalized prediction models may improve decision-making for the patient and surgeon alike., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To evaluate the incidence, risk factors, and patient-reported outcomes (PROs) of adult spinal deformity (ASD) patients with postoperative coronal malalignment., Methods: A single-institution, retrospective cohort study of ASD patients undergoing ≥ 6 level fusions from 2015 to 2019 was undertaken. The primary outcome was postoperative coronal malalignment, defined as C7-coronal vertical axis (CVA) > 3 cm. Secondary outcomes included: complications, readmissions, reoperations, and 2-year PROs., Results: A total of 243 ASD patients undergoing spinal surgery had preoperative and immediate postoperative measurements, and 174 patients (72%) had 2-year follow-up. Mean age was 49.3 ± 18.3yrs and mean instrumented levels was 13.5 ± 3.9. Mean preoperative CVA was 2.9 ± 2.7 cm, and 90 (37%) had preoperative coronal malalignment. Postoperative coronal malalignment occurred in 43 (18%) patients. Significant risk factors for postoperative coronal malalignment were: preoperative CVA (OR 1.21, p = 0.001), preoperative SVA (OR 1.05, p = 0.046), pelvic obliquity (OR 1.21; p = 0.008), Qiu B vs. A (OR 4.17; p = 0.003), Qiu C vs. A (OR 7.39; p < 0.001), lumbosacral fractional (LSF) curve (OR 2.31; p = 0.021), max Cobb angle concavity opposite the CVA (OR 2.10; p = 0.033), and operative time (OR 1.16; p = 0.045). Postoperative coronal malalignment patients were more likely to sustain a major complication (31% vs. 14%; p = 0.01), yet no differences were seen in readmissions (p = 0.72) or reoperations (p = 0.98). No significant differences were seen in 2-year PROs (p > 0.05)., Conclusions: Postoperative coronal malalignment occurred in 18% of ASD patients and was most associated with preoperative CVA/SVA, pelvic obliquity, Qiu B/C curves, LSF curve concavity to the same side as the CVA, and maximum Cobb angle concavity opposite side of the CVA. Postoperative coronal malalignment was significantly associated with increased complications but not readmission, reoperation, or 2-year PROs., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Identifying beneficial preventive strategies for surgical-site infection (SSI) in individual patients with different clinical and surgical characteristics is challenging. The purpose of this study was to investigate the association between preventive strategies and patient risk of SSI taking into consideration baseline risks and estimating the reduction of SSI probability in individual patients attributed to these strategies., Methods: Pediatric patients who underwent primary, revision, or final fusion for their spinal deformity at 7 institutions between 2004 and 2018 were included. Preventive strategies included the use of topical vancomycin, bone graft, povidone-iodine (PI) irrigations, multilayered closure, impermeable dressing, enrollment in quality improvement (QI) programs, and adherence to antibiotic prophylaxis. The CDC definition of SSI as occurring within 90 days postoperatively was used. Multiple regression modeling was performed following multiple imputation and multicollinearity testing to investigate the effect of preventive strategies on SSI in individual patients adjusted for patient and surgical characteristics., Results: Univariable regressions demonstrated that enrollment in QI programs and PI irrigation were significantly associated, and topical vancomycin, multilayered closure, and correct intraoperative dosing of antibiotics trended toward association with reduction of SSI. In the final prediction model using multiple regression, enrollment in QI programs remained significant and PI irrigation had an effect in decreasing risks of SSI by average of 49% and 18%, respectively, at the individual patient level., Conclusion: Considering baseline patient characteristics and predetermined surgical and hospital factors, enrollment in QI programs and PI irrigation reduce the risk of SSI in individual patients. Multidisciplinary efforts should be made to implement these practices to increase patient safety., Level of Evidence: Prognostic level III study., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: Restoring coronal alignment in spine deformity patients has been shown to play an important role in improving patient reported outcomes (PRO). Recently, the "kickstand rod" (KSR) technique was developed as a novel coronal correction method in complex spine deformity cases. The goal of the present study was to assess outcomes of this technique at two years of follow-up., Methods: Consecutive, unique adult patients who underwent KSR constructs for coronal spinal malalignment between 2015 and 2019 with a minimum 2 year clinical and radiographic follow-up were identified. A KSR construct includes a more laterally placed iliac screw and additional rod that effectively depresses the ipsilateral ilium/pelvis for coronal correction, while serving as a buttress to prevent future loss of correction. Outcomes included revision for instrumentation-related complications, radiographic alignment, and PROs., Results: Twenty patients were included with a mean age of 54 years [range: 20-73 years]. Mean follow-up time was 2.5 years [range: 2.0-5.0]. Mean number of levels fused was 17.3 [range: 10-24]. There were significant improvements in coronal alignment (CVA: 5.8 cm ± 2.6 cm vs. 1.7 cm ± 1.5 cm), sagittal alignment (SVA: 5.6 cm ± 5.9 cm vs. 1.6 cm ± 2.5 cm) and major Cobb angle (55º ± 32 vs. 26º ± 21) maintained at 2 years (p < 0.05). One patient experienced an asymptomatic fracture at the shank of the KSR iliac screw. There were significant improvements in Oswestry Disability Index and SRS-22 domains (p < 0.05)., Conclusion: The KSR technique is a safe and effective method for correcting coronal malalignment in complex spinal deformity patients with no revisions specific for the KSR or iliac screw and significantly improved PROs at a minimum two-year follow-up., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Objective: The purpose of this study is to highlight our technique for freehand placement of juxtapedicular screws along with intraoperative computed tomography (CT) and radiographic results., Methods: Consecutive patients with adult idiopathic scoliosis undergoing primary surgery by the senior author were identified. All type D (absent/slit like channel) pedicles were identified on preoperative CT. Three-dimensional visualization software was used to measure screw angulation and purchase. Radiographs were measured by a fellowship trained spine surgeon. The freehand technique was used to place all screws in a juxtapedicular fashion without any fluoroscopic, radiographic, navigational or robotic assistance., Results: Seventy-three juxtapedicular screws were analyzed. The most common level was T7 (9 screws) on the left and T5 (12 screws) on the right. The average medial angulation was 20.7° (range, 7.1°-36.3°), lateral vertebral body purchase was 13.4 mm (range, 0-28.9 mm), and medial vertebral body purchase was 21.1 mm (range, 8.9-31.8 mm). More than half (53.4%) of the screws had bicortical purchase. Two screws were lateral on CT scan, defined by the screw axis lateral to the lateral vertebral body cortex. No screws were medial. There was a difference in medial angulation between screws with (n = 58) and without (n = 15) lateral body purchase (22.0 ± 4.9 vs. 15.5 ± 4.5, p < 0.001). Three of 73 screws were repositioned after intraoperative CT. There were no neurovascular complications. The mean coronal cobb corrections for main thoracic and lumbar curves were 83.0% and 80.5%, respectively, at an average of 17.5 months postoperative., Conclusion: Freehand juxtapedicular screw placement is a safe technique for type D pedicles in adult idiopathic scoliosis patients.

Objective: The role of the craniocervical complex in spinal sagittal alignment has rarely been analyzed but it may play a fundamental role in postoperative mechanical complications. The aim of the study is to analyze the normative value of the cervical inclination angle (CIA) in an adult asymptomatic multiethnic population., Methods: Standing full-spine EOS of adult asymptomatic volunteers from 5 different countries were analyzed. The CIA was analyzed globally and then in each decade of life. Different ethnicities were compared. Comparisons between different groups was performed using a t-test and statistical significance was considered with a p-value < 0.05., Results: EOS of 468 volunteers were analyzed. The global mean CIA was 80.2° with a maximum difference of 9° between T1 and T12 (p < 0.001). The CIA remains constant until 60 years old then decreases significantly passing from a mean value before 20 years old of 82.25° to 73.65° after 70 years old. A statistically significant difference was found between the Arabics and other ethnicities with the formers having an inferior CIA: this was related to a mean older age (p < 0.05) and higher body mass index (p < 0.05) in the Arabics., Conclusion: The CIA remains constant until 60 years old and then reduces slightly but never under 70°. This angle is helpful to evaluate the lever arm at the upper instrumented vertebra after an adult spinal deformity surgery and could predict the occurrence of a proximal junctional kyphosis when its value is lower than normal. Further clinical studies must confirm this theory.

Background: Tranexamic acid (TXA) is an anti-fibrinolytic effective in reducing blood loss in orthopedic surgery. The appropriate dosing protocol for adult spinal deformity (ASD) surgery is not known. The purpose of this study was to evaluate two TXA protocols [low dose (L): 10 mg/kg bolus, 1 mg/kg/hr infusion; high dose (H): 50 mg/kg, 5 mg/kg/hr] in complex ASD surgery., Methods: Inclusion criteria were ASD reconstructions with minimum 10 fusion levels or planned 3-column osteotomy (3CO). Standard demographic and surgical data were collected. Intraoperative estimated blood loss (EBL) was calculated by suction canisters minus irrigation plus estimated blood lost in sponges, estimated to the nearest 50 mL. Serious adverse events (SAE) were defined a priori as: venothromboembolic event (VTE), cardiac arrhythmia, myocardial infarction, renal dysfunction, and seizure. All SAE were recorded. Simple t tests compared EBL between groups. Mean EBL by total blood volume (TBV), transfusion volume, complications related to TXA were secondary outcomes., Results: Sixty-two patients were enrolled and 52 patients completed the study; 25 were randomized to H and 27 to L. Demographic and surgical variables were not different between the two groups. EBL was not different between groups (H: 1596 ± 933 cc, L: 2046 ± 1105 cc, p = 0.12, 95% CI: - 1022 to 122 cc). EBL as a percentage of TBV was lower for the high-dose group (H: 29.5 ± 14.8%, L: 42.5 ± 26.2%, p = 0.03). Intraoperative transfusion volume (H: 961 ± 505 cc, L: 1105 ± 808 cc, p = 0.5) and post-operative transfusion volume (H: 513 ± 305 cc, L: 524 ± 245 cc, p = 0.9) were not different. SAE related to TXA were not different (p = 0.7) and occurred in 2 (8%) H and 3 (11%) L. There was one seizure (H), 2 VTE, and 2 arrhythmias., Conclusion: No differences in EBL, transfusion volume, nor SAE were observed between H and L dose TXA protocols. High dose was associated with decreased TBV loss (13%). Further prospective study, with pharmacologic analysis, is required to determine appropriate TXA dosage in ASD surgeries., Level of Evidence: Therapeutic Level II., Trial Registration: The study was registered at Clinicaltrials.gov (NCT02053363) February 3, 2014., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Substantial bleeding occurs during spinal fusion surgery in the pediatric population, and many patients receive allogeneic red blood cell transfusion (ARBT) for the treatment of resulting perioperative anemia. ARBT is thought to increase vulnerability to postoperative infections following major surgical procedures, but studies of this relationship in children undergoing spinal fusion have yielded conflicting results., Methods: Patients who underwent spinal fusion before the age of 18 years were identified from the National Surgical Quality Improvement Program-Pediatric (NSQIP-P) 2016 to 2019 databases, along with patient and procedure-specific characteristics, transfusion events and volumes, and postoperative infectious complications such as wound-related infection, pneumonia, urinary tract infection (UTI), and sepsis. Multivariable logistic regression analyses provided adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the association between ARBT and each infection outcome and the overall risk of infection., Results: Among 19,159 patients studied, 714 (3.7%) developed a total of 931 episodes of postoperative infection. In multivariable logistic regression analyses, perioperative ARBT was independently associated with postoperative pneumonia (aOR = 1.93, 95% CI = 1.40 to 2.68), UTI (aOR = 1.80, 95% CI = 1.19 to 2.73), sepsis (aOR = 1.58, 95% CI = 1.10 to 2.28), and the overall risk of infection (aOR = 1.40, 95% CI = 1.20 to 1.64). The risk of any postoperative infection increased in a dose-response fashion with transfusion volume., Conclusions: ARBT in pediatric spinal fusion is associated with significantly increased risks of postoperative pneumonia, UTI, and sepsis. The overall risk of postoperative infection increases with the volume transfused. Enhanced efforts to minimize perioperative anemia and ARBT should be considered as a means of improving patient outcomes., Level of Evidence: Prognostic 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/JBJSOA/A427)., (Copyright © 2022 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Objective: The purpose of this study was to determine the incidence, mechanism, and potential protective strategies for pelvic fixation failure (PFF) within 2 years after adult spinal deformity (ASD) surgery., Methods: Data for ASD patients (age ≥ 18 years, minimum of six instrumented levels) with pelvic fixation (S2-alar-iliac [S2AI] and/or iliac screws) with a minimum 2-year follow-up were consecutively collected (2015-2019). Patients with prior pelvic fixation were excluded. PFF was defined as any revision to pelvic screws, which may include broken rods across the lumbosacral junction requiring revision to pelvic screws, pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws, a broken or loose pelvic screw, or sacral/iliac fracture. Patient information including demographic data and health history (age, sex, BMI, smoking status, American Society of Anesthesiologists score, osteoporosis), operative (total instrumented levels [TIL], three-column osteotomy [3CO], interbody fusion), screw (iliac, S2AI, length, diameter), rod (diameter, kickstand), rod pattern (number crossing lumbopelvic junction, lowest instrumented vertebra [LIV] of accessory rod[s], lateral connectors, dual-headed screws), and pre- and postradiographic (lumbar lordosis, pelvic incidence, pelvic tilt, major Cobb angle, lumbosacral fractional curve, C7 coronal vertical axis [CVA], T1 pelvic angle, C7 sagittal vertical axis) parameters was collected. All rods across the lumbosacral junction were cobalt-chrome. All iliac and S2AI screws were closed-headed tulips. Both univariate and multivariate analyses were performed to determine risk factors for PFF., Results: Of 253 patients (mean age 58.9 years, mean TIL 13.6, 3CO 15.8%, L5-S1 interbody 74.7%, mean pelvic screw diameter/length 8.6/87 mm), the 2-year failure rate was 4.3% (n = 11). The mechanisms of failure included broken rods across the lumbosacral junction (n = 4), pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws (n = 3), broken pelvic screw (n = 1), loose pelvic screw (n = 1), sacral/iliac fracture (n = 1), and painful/prominent pelvic screw (n = 1). A higher number of rods crossing the lumbopelvic junction (mean 3.8 no failure vs 2.9 failure, p = 0.009) and accessory rod LIV to S2/ilium (no failure 54.2% vs failure 18.2%, p = 0.003) were protective for failure. Multivariate analysis demonstrated that accessory rod LIV to S2/ilium versus S1 (OR 0.2, p = 0.004) and number of rods crossing the lumbar to pelvis (OR 0.15, p = 0.002) were protective, while worse postoperative CVA (OR 1.5, p = 0.028) was an independent risk factor for failure., Conclusions: The 2-year PFF rate was low relative to what is reported in the literature, despite patients undergoing long fusion constructs for ASD. The number of rods crossing the lumbopelvic junction and accessory rod LIV to S2/ilium relative to S1 alone likely increase construct stiffness. Residual postoperative coronal malalignment should be avoided to reduce PFF.

Study Design: Prospective cohort., Objective: To prospectively evaluate PROs up to 5-years after complex ASD surgery., Methods: The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers. Inclusion criteria was Cobb angle of >80°, corrective osteotomy for congenital or revision deformity, and/or 3-column osteotomy. The following PROs were measured prospectively at intervals up to 5-years postoperative: ODI, SF36-PCS/MCS, SRS-22, NRS back/leg. Among patients with 5-year follow-up, comparisons were made from both baseline and 2-years postoperative to 5-years postoperative. PROs were analyzed using mixed models for repeated measures., Results: Seventy-seven patients (28.3%) had 5-year follow-up data. Comparing baseline to 5-year data among these 77 patients, significant improvement was seen in all PROs: ODI (45.2 vs. 29.3, P < 0.001), SF36-PCS (31.5 vs. 38.8, P < 0.001), SF36-MCS (44.9 vs. 49.1, P = 0.009), SRS-22-total (2.78 vs. 3.61, P < 0.001), NRS-back pain (5.70 vs. 2.95, P < 0.001) and NRS leg pain (3.64 vs. 2.62, P = 0.017). In the 2 to 5-year follow-up period, no significant changes were seen in any PROs. The percentage of patients achieving MCID from baseline to 5-years were: ODI (62.0%) and the SRS-22r domains of function (70.4%), pain (63.0%), mental health (37.5%), self-image (60.3%), and total (60.3%). Surprisingly, mean values ( P > 0.05) and proportion achieving MCID did not differ significantly in patients with major surgery-related complications compared to those without., Conclusions: After complex ASD surgery, significant improvement in PROs were seen at 5-years postoperative in ODI, SF36-PCS/MCS, SRS-22r, and NRS-back/leg pain. No significant changes in PROs occurred during the 2 to 5-year postoperative period. Those with major surgery-related complications had similar PROs and proportion of patients achieving MCID as those without these complications.

Owing to rapidly changing global demographics, adult spinal deformity (ASD) now accounts for a significant proportion of the Global Burden of Disease. Sagittal imbalance caused by age-related degenerative changes leads to back pain, neurological deficits, and deformity, which negatively affect the health-related quality of life (HRQoL) of patients. Along with the recognized regional, global, and sagittal spinopelvic parameters, poor paraspinal muscle quality has recently been acknowledged as a key determinant of the clinical outcomes of ASD. Although the Scoliosis Research Society-Schwab ASD classification system incorporates the radiological factors related to HRQoL, it cannot accurately predict the mechanical complications. With the rapid advances in surgical techniques, many surgical options for ASD have been developed, ranging from minimally invasive surgery to osteotomies. Therefore, structured patient-specific management is important in surgical decision-making, selecting the proper surgical technique, and to prevent serious complications in patients with ASD. Moreover, utilizing the latest technologies such as robotic-assisted surgery and machine learning, should help in minimizing the surgical risks and complications in the future.

Study Design: Retrospective cohort., Objective: Determine the rate and risk factors for S2AI screw-related pain after adult spinal deformity surgery with a minimum 2-year follow-up., Methods: A consecutive 83 spinal deformity patients undergoing surgical treatment between August 2015 and December 2017 with minimum 2-year follow-up for S2AI screw complication and screw-related pain were included. Linear regression was performed on various risk factors and postoperative S2AI screw-related pain. Subset analysis of 53 patients was performed on preoperative and postoperative SRS and ODI scores, operative data, and radiographic data., Results: The overall proportion of S2AI screw-related pain was 9.6%. An S2AI screw complication was identified radiographically in 10.8% of patients; among these, 22.2% experienced S2AI screw-related pain. 3.4% of all patients underwent S2A1 screw removal. The SRS, ODI, sagittal vertical axis (SVA), and coronal alignment scores/measurements improved following treatment in all patients. However, the mean difference for the pre and postoperative SRS function score (1.2 ± 0.5 vs 0.9 ± 0.8) and SVA (4.0 ± 4.9 cm vs 2.1 ± 4.8 cm) were higher for the pain group., Conclusions: A minimum 2-year analysis of S2AI screw fixation in adult spinal deformity patients showed that 9.6% of patients experienced S2AI screw-related pain and 3.4% of patients had S2A1 screws removed. The size and the number of S2AI screws did not predict postoperative pain, nor were radiographic findings correlated with clinical outcomes. The patient outcome scores, coronal alignment, and SVA improved for all patients, but within the pain group there was an overall larger change in the SVA and SRS function score.

Study Design: This is a cross-sectional cohort., Objective: The aim was to describe sagittal plane alignment and balance in a multinational cohort of nondegenerated, asymptomatic adults., Summary of Background Data: Current sagittal alignment targets were developed using correlations between radiographic and quality-of-life measures in spinal deformity patients, rather than disease-free samples leading to relatively poor accounting for variance within a population., Materials and Methods: Sagittal balance was defined using vertebral body tilt and spinopelvic alignment was defined as the vertebral pelvic angles from C2 to L5 (vertebral pelvic angle=vertebral tilt+pelvic tilt). Associations with pelvic incidence (PI) were assessed using linear regression. Multivariable linear regression was used to estimate a normal L1-S1 lordosis, adjusting for PI and the L1 pelvic angle (L1PA). Correlation between the L1 and T4 pelvic angles was assessed to define a normal thoracic alignment conditioned on lumbar alignment., Results: Among 320 volunteers from 4 continents, median age was 37% and 60% were female. C2 tilt was independent of PI with minimal variation. PI was inadequate for estimating a normal lumbar lordosis (L1-S1, r2 =0.3), but was strongly associated with the lumbar pelvic angles (L1PA, r2 =0.58). Defining lumbar lordosis as a function of PI and L1PA resulted in high explained variance ( R2 =0.74) and the T4 pelvic angle had near perfect correlation with the L1PA ( r =0.9)., Conclusions: We defined normal sagittal balance and spinopelvic alignment in a disease-free international volunteer cohort. Four parameters are either fixed or directly modifiable in surgery and can define a normal thoracic and lumbar alignment: the L1-S1 lordosis defined as a function of PI and the L1PA; and the T4 pelvic angle is nearly equivalent to the L1PA, aligning the T4-L1-hip axis., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Narrative Review., Objectives: The objective of this study was to compare publication status of clinical trials in adult spine surgery registered on ClinicalTrials.gov by funding source as well as to identify other trends in clinical trials in adult spine surgery., Methods: All prospective, comparative, therapeutic (intervention-based) trials of adult spinal disease that were registered on ClinicalTrials.gov with a start date of January 1, 2000 and completion date before December 17, 2018 were included. Primary outcome was publication status of published or unpublished. A bivariate analysis was used to compare publication status to funding source of industry vs non-industry., Results: Our search identified 107 clinical trials. The most common source of funding was industry (62 trials, 57.9% of total), followed by University funding (26 trials, 24.3%). The results of 76 trials (71.0%) were published, with industry-funded trials less likely to be published compared to non-industry-funded trials (62.9% compared to 82.2%, P = .03). Of the 31 unpublished studies, 13 did not report any results on ClinicalTrials.gov, and of those with reported results, none was a positive trial., Conclusions: Clinician researchers in adult spine surgery should be aware that industry-funded trials are less likely to go on to publication compared to non-industry-funded trials, and that negative trials are frequently not published. Future opportunities include improvement in result reporting and in publishing negative studies.

Objective: Adjacent segment disease, junctional kyphosis/failure and pseudarthrosis can negatively impact the mid to long-term outcome in spinal deformity surgery. These complications might be influenced by upper instrumented vertebra (UIV) fixation techniques. In this study we analyze key biomechanical properties of three different UIV fixation techniques and define their ideal clinical use based on patient-specific risk profiles using a finite element analysis (FEA) model., Methods: A T9-pelvis posterior instrumented spinal fusion was assumed. Three different FEA models were created based on the UIV fixation technique: T9 pedicle screws (PS); T9 cortical bone screws (CBS); T9 transverse process hooks (TPH). The three FEA models consisted of T8-T10 bone and ligamentous anatomy derived from a CT scan of a healthy patient as well as spinal implants consisting of either pedicle screws, cortical bone screws or transverse process hooks as well as cobalt chromium rods. The FEA models were constrained at T10, axial load as assumed for a healthy 80 kg male during flexion, extension and lateral bending were applied. As surrogate markers for risk of proximal junctional kyphosis, proximal junctional failure, adjacent segment disease and pseudarthrosis the following biomechanical parameters were calculated: UIV range of motion (ROM); intradiscal stress at UIV/UIV + 1; UIV intravertebral stress and screw pull out forces. One-way ANOVA analyses have been performed to compare biomechanical outcome parameters between the three construct variants under investigation., Results: UIV-ROM was restricted during flexion/extension/lateral bending by: PS: 73%/80%/86%, CBS: 71%/81%/85% and TPH: 62%/76%/85%. Average intradiscal stress at UIV/UIV + 1 during flexion/extension/lateral bending was (Mega Pascal, MPa): PS 0.42/0.44/0.38, CBS 0.49/0.4/0.44, TPH 0.66/0.51/0.58; average intravertebral stress of the UIV superior endplate during flexion/extension/lateral bending was (MPa): PS 2.23/2.12/2.21, CBS 1.87/1.98/1.8, TPH 1.67/0.98/1.53. Screw pull-out forces (N) at UIV during flexion/extension/lateral bending were: PS 476/320/375, CBS 444/245/308. Statistically significant differences were found for intradiscal stress as well as vertebral body average stress (p = 0.02 and p = 0.02)., Conclusion: Different UIV fixation techniques carry different biomechanical properties. Pedicle screw fixation is the most rigid, leading to the highest UIV stress and UIV screw pull out forces. Cortical bones screw fixation is similarly rigid; however, UIV stress and UIV screw pull out is significantly lower. Transverse process hook fixation is the least rigid, with the lowest UIV stress, however highest intradiscal stress at UIV/UIV + 1. Thus, these biomechanical differences may help select optimal UIV fixation techniques according to patient specific risk factors., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Objective: Spine surgeons have a heuristic sense of how to surgically restore alignment and address adult spinal deformity (ASD) symptoms, but consensus on the extent of treatment remains unclear. We sought to determine the variability of surgical approaches in treating ASD., Methods: Sixteen spine surgeons were surveyed on treatment approaches in 10 select ASD cases. We repeated the survey with the same surgeons 4 weeks later, with cases ordered differently. We examined the variability in length of construct, use of interbody spacers, osteotomies, and pelvic fixation frequency., Results: Treatment approaches for each case varied by surgeon, with some surgeons opting for long fusion constructs in cases for which others offered no surgery. There was no consensus among surgeons on the number of levels fused, interbody spacer use, or anterior/posterior osteotomies. Intersurgeon and intrasurgeon variability was 48% (kappa = 0.31) and 59% (kappa = 0.44) for surgeons performing minimally invasive surgery (MIS) versus 37% (kappa = 0.21) and 47% (kappa = 0.30) for those performing open surgery. In the second-round survey, 8 of 15 (53%) surgeons substantially changed the construct length, number of interbody spacers, and osteotomies in at least half the cases they previously reviewed. Surgeons performing MIS versus open surgery were less likely to extend constructs to the pelvis (42.5% vs. 67.5%; P = 0.02), but construct length was not correlated with whether a surgeon performed MIS or open surgery., Conclusions: Spinal deformity surgeons lack consensus on the optimal surgical approach for treating ASD. Classifying surgeons as performing MIS or open surgery does not mitigate this variability., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: This current systematic review sought to identify and evaluate all current research-based spine surgery applications of AI/ML in optimizing preoperative patient selection, as well as predicting and managing postoperative outcomes and complications., Methods: A comprehensive search of publications was conducted through the EMBASE, Medline, and PubMed databases using relevant keywords to maximize the sensitivity of the search. No limits were placed on level of evidence or timing of the study. Findings were reported according to the PRISMA guidelines., Results: After application of inclusion and exclusion criteria, 41 studies were included in this review. Bayesian networks had the highest average AUC (.80), and neural networks had the best accuracy (83.0%), sensitivity (81.5%), and specificity (71.8%). Preoperative planning/cost prediction models (.89,82.2%) and discharge/length of stay models (.80,78.0%) each reported significantly higher average AUC and accuracy compared to readmissions/reoperation prediction models (.67,70.2%) ( P < .001, P = .005, respectively). Model performance also significantly varied across postoperative management applications for average AUC and accuracy values ( P < .001, P < .027, respectively)., Conclusions: Generally, authors of the reviewed studies concluded that AI/ML offers a potentially beneficial tool for providers to optimize patient care and improve cost-efficiency. More specifically, AI/ML models performed best, on average, when optimizing preoperative patient selection and planning and predicting costs, hospital discharge, and length of stay. However, models were not as accurate in predicting postoperative complications, adverse events, and readmissions and reoperations. An understanding of AI/ML-based applications is becoming increasingly important, particularly in spine surgery, as the volume of reported literature, technology accessibility, and clinical applications continue to rapidly expand.

Objective: To validate the authors kyphosis correction formula for pedicle subtraction osteotomy (PSO) cases. Additionally, to use the formula to evaluate the safety of PSO by determining if there is anterior lengthening., Methods: Twenty-two patients with primarily kyphosis corrected by PSO and with clear landmarks on preoperative and postoperative x-rays were selected. Several anatomical lines and angle measurements were utilized as depicted previously in the Vertebral Column Resection formula (see below). Two approximations were calculated: the geometric approximation (G) = (tanG°*2 + 1)*15° and the rough approximation (R) which is about the same amount of actual shortening (x), if parallel length (y) ≥ 40; twice of x, if y < 40. For each patient, the change of segmental kyphosis angle (K°) was measured and compared with G° and R°, and the correlation between each value was analyzed., Results: The absolute Mean ± SE for K - G and K - R was 2.33° ± 0.34 and 6.09° ± 0.58, respectively. K - G is < 3° (p = 0.03). K - R is < 8° (p = 0.001). In other words, K was close to G and R and thus can be predicted by these approximations. Average posterior shortening, anterior shortening, and kyphosis correction at each level were 20.8 ± 2.0 mm, - 3.64 ± 1.5 mm (which equates to anterior lengthening), and 31.05° ± 2.0, respectively. Anterior lengthening occurred in 13 cases (in 4 cases, both at the body as well as at the disc above and below.) The correlation between posterior and anterior shortening was 0.03 (p = 0.88). There were 3 cage insertion cases: 1 had anterior lengthening, while 2 had anterior shortening even with the cage., Conclusion: This study validated the geometric and rough approximations originally used in PVCR patients, for PSO patients. Additionally, this study found that anterior lengthening may occur in PSOs usually at the discs, but occasionally at the osteotomized body., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Accurate reporting of long-term complications of surgical treatment of adolescent idiopathic scoliosis (AIS) is critical, but incomplete. This study aimed to report on the rate of complications following surgical treatment of AIS among patients with at least 10 years of follow-up., Methods: This was a retrospective review of prospectively collected data from a multicenter registry of patients who underwent surgical treatment for AIS with minimum 10-year follow-up. Previously published complications were defined as major if they resulted in reoperation, prolonged hospital stay/readmission, neurological deficits, or were considered life-threatening. Rates and causes of reoperations were also reviewed., Results: Two hundred and eighty-two patients were identified with mean age at surgery of 14.6 ± 2.1 years. Mean follow-up was 10.6 (range 9.5-14) years. Eighty-seven patients had anterior spinal fusion (ASF); 195 had posterior spinal fusion (PSF). The overall major complication rate was 9.9% (n = 28) in 27 patients. Among PSF patients, the complication rate was 9.7% (n = 19) in 18 patients. The complications were surgical site infection (37%), adding-on (26%), pulmonary (16%), neurologic (11%), instrumentation (5%), and gastrointestinal (5%). In ASF patients, the complication rate was 10.3% (n = 9) among nine patients. The complications were pulmonary (44%), pseudoarthrosis (22%), neurologic (11%), adding-on (11%), and gastrointestinal (11%). The reoperation rate was 6.0% (n = 17) among 17 patients. Although most of the complications presented within the first 2 years (60.7%), surgical site infection and adding-on were also seen late into the 10-year period., Conclusion: This is the largest prospective study with at least a 10-year follow-up of complications following spinal fusion for AIS, the overall major complication rate was 9.9% with a reoperation rate of 6.0%. Complications presented throughout the 10-year period, making long-term follow-up very important for surveillance., Level of Evidence: Therapeutic II., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: Assess whether a novel deformity angular ratio (DAR) calculated using preoperative three-dimensional computed tomography (3D CT) is more accurate than total DAR (T-DAR) radiographic measurements at predicting intraoperative neuromonitoring (IONM) events during vertebral column resection (VCR)., Methods: Consecutive, unique patients undergoing thoracic VCR by a single surgeon from 2015 to 2021 were identified. The T-DAR was calculated by dividing the total radiographic Cobb angle by the number of vertebral segments the angle subtends. 3D CT DAR was calculated for each patient from a preoperative CT scan by finding the maximum angle subtended by three contiguous vertebral segments. All patients were assessed for IONM events. A binary threshold of 25 was used for T-DAR and 3D CT DAR measurements for predictive analysis. p < 0.05 indicated significance., Results: In total, 68 patients were identified. Mean age was 28 years. Mean levels fused was 15. Twenty-one patients (31%) had IONM events. In patients, with and without an IONM event, mean T-DAR was 26.6 ± 9.8 and 21.5 ± 8.8 (p = 0.04), respectively. 3D CT DAR mean values were 26.4 ± 10.8 and 18.4 ± 5.6, respectively (p < 0.001). 3D CT DAR accurately classified 81% of patients with a positive predictive value (PPV) of 75%. In comparison, T-DAR accurately classified 60% of patients with a PPV of 39%., Conclusion: 3D CT substantially improves preoperative IONM event prediction when compared to traditional radiographic measurements. A 3D CT DAR of 25 or greater was correlated with an increased rate of IONM events. 3D CT reconstructions are a useful adjunct for planning prior to a VCR., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Objective: There is a paucity of literature on pelvic fixation failure after adult spine surgery in the early postoperative period. The purpose of this study was to determine the incidence of acute pelvic fixation failure in a large single-center study and to describe the lessons learned., Methods: The authors performed a retrospective review of adult (≥ 18 years old) patients who underwent spinal fusion with pelvic fixation (iliac, S2-alar-iliac [S2AI] screws) at a single academic medical center between 2015 and 2020. All patients had a minimum of 3 instrumented levels. The minimum follow-up was 6 months after the index spine surgery. Patients with prior pelvic fixation were excluded. Acute pelvic fixation failure was defined as revision of the pelvic screws within 6 months of the primary surgery. Patient demographics and operative, radiographic, and rod/screw parameters were collected. All rods were cobalt-chrome. All iliac and S2AI screws were closed-headed screws., Results: In 358 patients, the mean age was 59.5 ± 13.6 years, and 64.0% (n = 229) were female. The mean number of instrumented levels was 11.5 ± 5.5, and 79.1% (n = 283) had ≥ 6 levels fused. Three-column osteotomies were performed in 14.2% (n = 51) of patients, and 74.6% (n = 267) had an L5-S1 interbody fusion. The mean diameter/length of pelvic screws was 8.5/86.6 mm. The mean number of pelvic screws was 2.2 ± 0.5, the mean rod diameter was 6.0 ± 0 mm, and 78.5% (n = 281) had > 2 rods crossing the lumbopelvic junction. Accessory rods extended to S1 (32.7%, n = 117) or S2/ilium (45.8%, n = 164). Acute pelvic fixation failure occurred in 1 patient (0.3%); this individual had a broken S2AI screw near the head-neck junction. This 76-year-old woman with degenerative lumbar scoliosis and chronic lumbosacral zone 1 fracture nonunion had undergone posterior instrumented fusion from T10 to pelvis with bilateral S2AI screws (8.5 × 90 mm); i.e., transforaminal lumbar interbody fusion L4-S1. The patient had persistent left buttock pain postoperatively, with radiographically confirmed breakage of the left S2AI screw 68 days after surgery. Revision included instrumentation removal at L2-pelvis and a total of 4 pelvic screws., Conclusions: The acute pelvic fixation failure rate was exceedingly low in adult spine surgery. This rate may be the result of multiple factors including the preference for multirod (> 2), closed-headed pelvic screw constructs in which large-diameter long screws are used. Increasing the number of rods and screws at the lumbopelvic junction may be important factors to consider, especially for patients with high risk for nonunion.

Aim: To develop and validate a risk calculator based on preoperative factors to predict the probability of surgical site infection (SSI) in patients with cerebral palsy (CP) undergoing spinal surgery., Method: This was a multicenter retrospective cohort study of pediatric patients with CP who underwent spinal fusion. In the development stage, preoperative known factors were collected, and a risk calculator was developed by comparing multiple models and choosing the model with the highest discrimination and calibration abilities. This model was then tested with a separate population in the validation stage., Results: Among the 255 patients in the development stage, risk of SSI was 11%. A final prediction model included non-ambulatory status (odds ratio [OR] 4.0), diaper dependence (OR 2.5), age younger than 12 years (OR 2.5), major coronal curve magnitude greater than 90° (OR 1.3), behavioral disorder/delay (OR 1.3), and revision surgery (OR 1.3) as risk factors. This model had a predictive ability of 73.4% for SSI, along with excellent calibration ability (p = 0.878). Among the 390 patients in the validation stage, risk of SSI was 8.2%. The discrimination of the model in the validation phase was 0.743 and calibration was p = 0.435, indicating 74.3% predictive ability and no difference between predicted and observed values., Interpretation: This study provides a risk calculator to identify the risk of SSI after spine surgery for patients with CP. This will allow us to enhance decision-making and patient care while providing valid hospital comparisons, public reporting mechanisms, and reimbursement determinations., (© 2022 Mac Keith Press.)

Purpose: To validate the Scoliosis Research Society-22r (SRS-22r) question 11 (Q11) response as a measure to assess and quantify opioid consumption., Methods: A post hoc analysis of a prospective study regarding opioid use during ASD surgery was performed. Data were collected at enrollment and 2-year follow-up including the SRS-22r and a standardized data collection form (CRF) for self-reported opioid consumption. Responses to Q11 of the SS-22r were compared with responses to the opioid consumption CRF (as measured by morphine equivalent dose (MED)). Inter-rater agreement was calculated. Sensitivity and specificity for the Q11 (+) responses were calculated using MED reports as the "true" value., Results: Cohen's kappa indicated almost perfect agreement between the MED CRF and Q11 (k = 0.878, p < 0.001). Mean daily MED consumption for patients reporting "Daily Narcotic" use was 62.0 (Median: 38.7, SD 87.5) mg; for patients reporting "Narcotics weekly or less", mean daily MED consumption was 21.6 (15.0, 29.0) mg. The positive Q11 responses were 96% sensitive and 92% specific for opioid users., Conclusion: SRS-22r Q11 exhibits almost perfect agreement with an independent questionnaire designed to assess opioid consumption in this cohort. "Daily narcotic" users report nearly three times the mean daily MED of "Weekly or less" users (62.0 ± 87.5 mg vs 21.6 ± 29 mg, p = 0.037). Q11 exhibited excellent sensitivity and specificity for determining opioid users and non-users. Given the need for opioid research in ASD, Q11 may be useful to use existing registries and observational cohorts to design more definitive studies regarding opioid consumption., Level of Evidence: III., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: Retrospective cohort., Objective: The purpose was to investigate the incidence of and risk factors for complications associated with vertebroplasty (VP) or kyphoplasty (KP) for osteoporotic vertebral compression fracture (OVCF) using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database., Methods: A cohort of patients undergoing VP/KP was constructed from the 2011-2013 ACS-NSQIP dataset using Current Procedural Terminology (CPT) codes. The incidences of minor complications (i.e. urinary tract infection, pneumonia, renal insufficiency, superficial infection, wound dehiscence), major complications (i.e. reoperation, deep vein thrombosis, pulmonary embolism, sepsis, dialysis, cardiac arrest, deep infection, stroke), and mortality within 30 days post-surgery were investigated, and their risk factors were assessed using logistic regression modeling., Results: Of 1932 patients undergoing VP/KP, 166 (8.6%) experienced a complication, including minor complications in 53 (2.7%), major complications in 95 (4.9%), and death in 40 (2.1%). Multivariate logistic regression analysis indicated that the adjusted odds ratios (95% confidence interval [CI]) of mortality was significantly associated with ASA 4: 16.604 (1.956-140.959) and increased creatinine (≥ 1.3 mg/dL): 3.494 (1.128-10.823). History of chronic obstructive pulmonary disease was associated with minor complications. Increased WBC count and hypoalbuminemia (<3.0 g/dL) were also associated with major complications., Conclusions: The major complication and mortality rates associated with VP/KP were 4.9% and 2.1% respectively, higher than previous reports. Increased creatinine and ASA 4 were independently associated with mortality after VP/KP. Therefore, cautious monitoring and counseling is needed for elderly, patients with preexisting kidney disease or ASA 4 undergoing VP/KP.

Purpose: To expand on previously described intraoperative aids by developing consensus-based best practice guidelines to optimize the approach to intraoperative neuromonitoring (IONM) events associated with "high-risk" spinal deformity surgery., Methods: Consensus was established among a group of experienced spinal deformity surgeons by way of the Delphi method. Through a series of iterative surveys and a final virtual consensus meeting, participants expressed their agreement (strongly agree, agree, disagree, and strongly disagree) with various items. Consensus was defined as ≥ 80% agreement ("strongly agree" or "agree"). Near-consensus was defined as ≥ 60% but < 80%. Equipoise was ≥ 20% but < 60%, and consensus to exclude was < 20%., Results: 15 out of 15 (100%) invited surgeons agreed to participate. Final consensus supported inclusion of 105 items (53 in Response Algorithm, 13 in Ongoing Consideration of Etiology, 31 in Real-Time Data Scenarios, 8 in Patterns of IONM Loss), which were organized into a final set of best practice guidelines., Conclusion: Detailed consensus-based best practice guidelines and aids were successfully created with the intention to help organize and direct the surgical team in exploring and responding to neurological complications during high-risk spinal deformity surgery., Level of Evidence: Level V., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: To establish expert consensus on various parameters that constitute elevated risk during spinal deformity surgery and potential preventative strategies that may minimize the risk of intraoperative neuromonitoring (IONM) events and postoperative neurological deficits., Methods: Through a series of surveys and a final virtual consensus meeting, the Delphi method was utilized to establish consensus among a group of expert spinal deformity surgeons. During iterative rounds of voting, participants were asked to express their agreement (strongly agree, agree, disagree, strongly disagree) to include items in a final set of guidelines. Consensus was defined as ≥ 80% agreement among participants. Near-consensus was ≥ 60% but < 80% agreement, equipoise was ≥ 20% but < 60%, and consensus to exclude was < 20%., Results: Fifteen of the 15 (100%) invited expert spinal deformity surgeons agreed to participate. There was consensus to include 22 determinants of high-risk (8 patient factors, 8 curve and spinal cord factors, and 6 surgical factors) and 21 preventative strategies (4 preoperative, 14 intraoperative, and 3 postoperative) in the final set of best practice guidelines., Conclusion: A resource highlighting several salient clinical factors found in high-risk spinal deformity patients as well as strategies to prevent neurological events was successfully created through expert consensus. This is intended to serve as a reference for surgeons and other clinicians involved in the care of spinal deformity patients., Level of Evidence: Level V., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Background: Three-dimensional (3D) imaging represents a novel way to assess surgical derotation maneuvers in adolescent idiopathic scoliosis (AIS)., Objective: To assess the following in patients with AIS undergoing derotation surgery with Lenke type 1/2 curves using 3D imaging: (1) the primary outcome of thoracic apical vertebral rotation (T-AVR) and (2) secondary outcomes of thoracic kyphosis (TK), lumbar AVR (L-AVR), and rotation of each thoracic/lumbar vertebrae., Methods: A retrospective, pilot study of type 1/2 AIS patients from 2017 to 2018 was performed. All patients received posterior pedicle screw/rod constructs with consistent direct vertebral derotational maneuvers and received full length SterEOS imaging with 3D reconstruction. The primary outcome of interest was T-AVR. Secondary outcomes included TK, L-AVR, and rotation at each thoracic/lumbar vertebrae., Results: Fifteen patients (mean age 15.7 ± 1.2 years, 67.0% female) were studied. The mean preoperative/postoperative Cobb angle of the major curve was 51.8° ± 14.9° (range 39.8-62.0) and 11.0° ± 5.1° (range 3.7-20.7). Mean level fused was 10.5 ± 1.2. The primary outcome of T-AVR showed significant improvement (13.8° ± 12.5° vs 9.2° ± 8.6°, P = .015) after surgery, along with secondary outcome of TK (T1-12/T4-12, P = .008/.027). Significant spontaneous rotational improvement was seen in L-AVR (P = .016). Significant improvement was also seen in 11 of 17 (64.7%) individual vertebrae (T3-8/T11-L3) (P < .05)., Conclusion: In Lenke Type 1/2 AIS patients undergoing surgical derotation and fusion, 3D imaging techniques captured improvements in rotation. Significant postoperative improvement was seen in T-AVR, TK, L-AVR, and rotation of the individual vertebrae T3-8/T11-L3. These pilot results warrant the study of 3D imaging in all patients with AIS and other scoliosis populations., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: The purpose of this study was to investigate the affecting factors on pelvic incidence (PI) and to test the hypothesis that PI changes even after skeletal maturity probably due to hypermobility of the sacroiliac joint using a large international multi-center database., Methods: A prospective and cross-sectional healthy adult volunteers, ages 18-80 years, across 5 countries were used. Radiographic measurements included standard whole body alignment parameters. Bivariate regression analyses between PI versus demographics and spino-pelvic anatomical parameters were performed. An effect of sex on pelvic anatomical parameters was also investigated. Multivariate logistic regression with a forward stepwise procedure was performed to identify the contributing factors to PI, and an appropriate model was obtained., Results: PI showed a significant positive correlation with age in pooled data. Divided by sex, however, there was no correlation in men, but women showed a significant higher correlation coefficient. Pelvic thickness (PTh) had a significant negative correlation with age in pooled data. Divided by sex, no correlation was found in men, but there was a significant correlation in women with higher correlation coefficient. The stepwise multivariate analysis for the factors on PI identified four significant factors: age, sex, ethnicity, and PTh., Conclusions: PTh, sex, ethnicity, and age affected PI. There was a positive correlation between PI and age. The tendency was more significant in woman than in man. The results support the hypothesis that PI increases with aging, but the change seems to be small and needs to be verified in a longitudinal evaluation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The major focus of realignment in adult spinal deformity (ASD) surgery has been on the sagittal plane, and less emphasis has been given to the coronal plane. In light of this overlooked area within ASD surgery, we aimed to refocus the narrative on coronal alignment in ASD surgery. The objectives of the current narrative review were to (1) define coronal alignment and discuss existing measurements; (2) report the incidence and prevalence of coronal malalignment (CM); (3) discuss the impact of CM on clinical outcomes; and (4) describe our preferred treatment algorithm of surgical correction of CM in ASD., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Previous studies on adults with degenerative scoliosis (ADS) have been fixed the threshold of PI-LL mismatch less than 10° for achieving good clinical outcomes. Recent studies discussed that PI-LL mismatch should consider individual pelvic incidence (PI) and should be set first in a normal population. The purpose of this study is to assess the variability of PI-LL mismatch according to PI in an asymptomatic population., Methods: Full-body low dose stereoradiographic evaluation was done in a multi-ethnic cohort of 468 asymptomatic adult volunteers. Patients were clustered in three groups depending on individual PI values: PI < 45°, 45° < PI < 60° and PI > 60°. 3D measurements were performed using a commercially available 2D/3D modeling software to establish a correlation of PI with other spinopelvic parameters. ANOVA and Tukey's HSD for post-hoc analysis were used to determine the differences between the three groups., Results: In our asymptomatic population, the mean value of PI-LL mismatch is - 5.4° ± 10.7°. Clusterization of the population reveals significant differences in the distribution of L1S1 lordosis, pelvic tilt and PI-LL with positive linear correlation according to PI values. As an interestingly result, PI-LL mismatch is equal to 0° when PI is around 64°., Conclusions: The present study demonstrated that PI-LL mismatch is negative in an asymptomatic population (- 5.4° ± 10.7°) and the value should be customized to each patient to be able to restore the appropriate lordosis in ADS. The PI-LL mismatch is given by the formula PI-LL = - 28.5 + 0.44 × PI., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Coronal malalignment (CM) is a challenging spinal deformity to treat. The kickstand rod (KR) technique is powerful for correcting truncal shift. This study tested the hypothesis that the KR technique provides superior coronal alignment correction in adult deformity compared with traditional rod techniques., Methods: A retrospective evaluation of a prospectively collected multicenter database was performed. A 2:1 matched cohort of non-KR accessory rod and KR patients was planned based on preoperative coronal balance distance (CBD) and a vector of global shift. Patients were subgrouped according to CM classification with a 30-mm CBD threshold defining CM, and comparisons of surgical and clinical outcomes among groups was performed., Results: Twenty-one patients with preoperative CM treated with a KR were matched to 36 controls. KR-treated patients had improved CBD compared with controls (18 vs. 35 mm, P < 0.01). The postoperative CBD did not result in clinical differences between groups in patient-reported outcomes (P ≥ 0.09). Eight (38%) of 21 KR patients and 12 (33%) of 36 control patients with preoperative CM had persistent postoperative CM (P = 0.72). CM class did not significantly affect the likelihood of treatment failure (postoperative CBD > 30 mm) in the KR cohort (P = 0.70), the control cohort (P = 0.35), or the overall population (P = 0.31)., Conclusions: Application of the KR technique to coronal spinal deformity in adults allows for successful treatment of CM. Compared to traditional rod techniques, the use of KRs did not improve clinical outcome measures 1 year after spinal deformity surgery but was associated with better postoperative coronal alignment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: The purpose of this study was to investigate associations between the various definitions of adding-on identified in the literature and HRQoL at 10 years following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) to identify a clinically relevant definition., Methods: In this retrospective cohort study, patients with Lenke type 1 or 2 AIS with 10-year follow-up after PSF were identified in a multicenter registry. Adding-on was identified independently using 5 published definitions and expert spine surgeons' visual confirmation. Worsening of HRQoL was defined as a preoperative to 10-year postoperative decrease in SRS-22 domain score ≥ the minimal clinically important difference (MCID)., Results: One hundred fifty patients were included, and 118 had HRQoL data available for the main analysis. Worsening pain was noted in 49 (41.5%) patients, appearance in 1 (0.8%), and activity in 70 (59.3%) from preoperative to postoperative. 4 of the 5 definitions of adding-on demonstrated no evidence of association with worsening HRQoL. By Cho's definition (either 1. ≥ 5° increase in Cobb angle AND increase in number of vertebrae in curve distally, or 2. ≥ 5° increase in angulation of 1st disc below LIV), adding-on (27 patients, 22.9%) was associated with an increased risk of worsening pain (59.3% vs. 36.3%, p = 0.033) and activity (77.8% vs. 53.8%, p = 0.026). There was no evidence of association with changes in appearance. Risk of worsening pain and activity was increased by 1.75 and 1.51 times (p = 0.023 and p = 0.002), respectively., Conclusion: Cho's definition of adding-on was associated with worsening HRQoL at 10 years following PSF for Lenke type 1 and 2 AIS. Consistent use of this definition will allow us to compare studies and obtain meaningful information in this population., Level of Evidence: Level II., (© 2021. The Author(s), under exclusive licence to Scoliosis Research Society.)