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Background: Our understanding of the relationship between sagittal alignment and mechanical complications is evolving. In normal spines, the L1-pelvic angle (L1PA) accounts for the magnitude and distribution of lordosis and is strongly associated with pelvic incidence (PI), and the T4-pelvic angle (T4PA) is within 4° of the L1PA. We aimed to examine the clinical implications of realignment to a normal L1PA and T4-L1PA mismatch., Methods: A prospective multicenter adult spinal deformity registry was queried for patients who underwent fixation from the T1-T5 region to the sacrum and had 2-year radiographic follow-up. Normal sagittal alignment was defined as previously described for normal spines: L1PA = PI × 0.5 - 21°, and T4-L1PA mismatch = 0°. Mechanical failure was defined as severe proximal junctional kyphosis (PJK), displaced rod fracture, or reoperation for junctional failure, pseudarthrosis, or rod fracture within 2 years. Multivariable nonlinear logistic regression was used to define target ranges for L1PA and T4-L1PA mismatch that minimized the risk of mechanical failure. The relationship between changes in T4PA and changes in global sagittal alignment according to the C2-pelvic angle (C2PA) was determined using linear regression. Lastly, multivariable regression was used to assess associations between initial postoperative C2PA and patient-reported outcomes at 1 year, adjusting for preoperative scores and age., Results: The median age of the 247 included patients was 64 years (interquartile range, 57 to 69 years), and 202 (82%) were female. Deviation from a normal L1PA or T4-L1PA mismatch in either direction was associated with a significantly higher risk of mechanical failure, independent of age. Risk was minimized with an L1PA of PI × 0.5 - (19° ± 2°) and T4-L1PA mismatch between -3° and +1°. Changes in T4PA and in C2PA at the time of final follow-up were strongly associated (r2 = 0.96). Higher postoperative C2PA was independently associated with more disability, more pain, and worse self-image at 1 year., Conclusions: We defined sagittal alignment targets using L1PA (relative to PI) and the T4-L1PA mismatch, which are both directly modifiable during surgery. In patients undergoing long fusion to the sacrum, realignment based on these targets may lead to fewer mechanical failures., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The International Spine Study Group (ISSG) is funded through research grants from NuVasive, SI-Bone, DePuy Synthes Spine, K2M, Stryker, Biomet, AlloSource, and Orthofix, and individual donations. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/I191)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Hip osteoarthritis (OA) is common in patients with adult spinal deformity (ASD). Limited data exist on the prevalence of hip OA in patients with ASD, or on its impact on baseline and postoperative alignment and patient-reported outcome measures (PROMs). Therefore, this paper will assess the prevalence and impact of hip OA on alignment and PROMs., Methods: Patients with ASD who underwent L1-pelvis or longer fusions were included. Two independent reviewers graded hip OA with the Kellgren-Lawrence (KL) classification and stratified it by severity into non-severe (KL grade 1 or 2) and severe (KL grade 3 or 4). Radiographic parameters and PROMs were compared among 3 patient groups: Hip-Spine (hip KL grade 3 or 4 bilaterally), Unilateral (UL)-Hip (hip KL grade 3 or 4 unilaterally), or Spine (hip KL grade 1 or 2 bilaterally)., Results: Of 520 patients with ASD who met inclusion criteria for an OA prevalence analysis, 34% (177 of 520) had severe bilateral hip OA and unilateral or bilateral hip arthroplasty had been performed in 8.7% (45 of 520). A subset of 165 patients had all data components and were examined: 68 Hip-Spine, 32 UL-Hip, and 65 Spine. Hip-Spine patients were older (67.9 ± 9.5 years, versus 59.6 ± 10.1 years for Spine and 65.8 ± 7.5 years for UL-Hip; p < 0.001) and had a higher frailty index (4.3 ± 2.6, versus 2.7 ± 2.0 for UL-Hip and 2.9 ± 2.0 for Spine; p < 0.001). At 1 year, the groups had similar lumbar lordosis, yet the Hip-Spine patients had a worse sagittal vertebral axis (SVA) measurement (45.9 ± 45.5 mm, versus 25.1 ± 37.1 mm for UL-Hip and 19.0 ± 39.3 mm for Spine; p = 0.001). Hip-Spine patients also had worse Veterans RAND-12 Physical Component Summary scores at baseline (25.7 ± 9.3, versus 28.7 ± 9.8 for UL-Hip and 31.3 ± 10.5 for Spine; p = 0.005) and 1 year postoperatively (34.5 ± 11.4, versus 40.3 ± 10.4 for UL-Hip and 40.1 ± 10.9 for Spine; p = 0.006)., Conclusions: This study of operatively treated ASD revealed that 1 in 3 patients had severe hip OA bilaterally. Such patients with severe bilateral hip OA had worse baseline SVA and PROMs that persisted 1 year following ASD surgery, despite correction of lordosis., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: Funding for this study was received from DePuy Synthes Spine, NuVasive, and K2/Stryker. In addition, the International Spine Study Group reports grants to the foundation from Medtronic, Globus, Stryker, SI Bone, and Carlsmed. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/H962)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: The Spinal Cord Shape Classification System (SCSCS) class has been associated with spinal cord monitoring data loss during spinal deformity surgery. The objective of the current study was to prospectively validate the SCSCS as a predictor of spinal cord monitoring data loss during spinal deformity surgery., Methods: A prospective cohort study of consecutive patients who were undergoing primary deformity surgery at a single institution from 2018 to 2023 and whose major curve was in the spinal cord region was undertaken. Spinal cord morphology at the apex of the major curve on preoperative axial T2-weighted magnetic resonance imaging was used to categorize patients into 3 spinal cord shape types based on the SCSCS. The primary outcome was intraoperative neuromonitoring (IONM) data loss related to spinal cord dysfunction. Demographics and surgical and radiographic variables were compared between patients with IONM data loss and those without loss. Predictors of IONM loss were determined using bivariate and multivariable logistic regression analyses., Results: A total of 256 patients (168 adult, 88 pediatric) were included and were separated into 3 SCSCS types: 110 (43.0%) with Type I, 105 (41.0%) with Type II, and 41 (16.0%) with Type III. IONM loss was observed in 30 (11.7%) of the 256 patients, including 7 (6.4%) of 110 with SCSCS Type I, 7 (6.7%) of 105 with Type II, and 16 (39.0%) of 41 with Type III. IONM loss was associated with SCSCS Type III, the preoperative deformity angular ratio, performance of 3-column osteotomies, greater operative time, greater transfusion volume, and greater postoperative sagittal corrections. SCSCS type was the strongest independent predictor of IONM data loss. SCSCS Type III had the greatest odds of IONM loss (odds ratio [OR] = 6.68, 95% confidence interval [CI] = 2.45 to 18.23 compared with Types I and II combined). The overall predictive performance with respect to IONM loss (area under the receiver operating characteristic curve = 0.827) was considered excellent., Conclusions: This prospective cohort study of patients undergoing spinal deformity correction confirmed that patients with a Type-III spinal cord shape had greater odds of IONM loss. Inclusion of the SCSCS in preoperative risk stratification and intraoperative management of spinal deformity corrective surgery is recommended., Level of Evidence: Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: No external funding was received for this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H906 )., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Surgery for adult spinal deformity (ASD) poses substantial risks, including the development of symptomatic pseudarthrosis, which is twice as prevalent among patients with osteoporosis compared with those with normal bone mineral density (BMD). Limited data exist on the impact of teriparatide, an osteoanabolic compound, in limiting the rates of reoperation and pseudarthrosis after treatment of spinal deformity in patients with osteoporosis., Methods: Osteoporotic patients on teriparatide (OP-T group) were compared with patients with osteopenia (OPE group) and those with normal BMD. OP-T patients were matched with OPE patients and patients with normal BMD at a 1:2:2 ratio. All patients had a minimum 2-year follow-up and underwent posterior spinal fusion (PSF) involving >7 instrumented levels. The primary outcome was the 2-year reoperation rate. Secondary outcomes included pseudarthrosis with or without implant failure, proximal junctional kyphosis (PJK), and changes in patient-reported outcomes (PROs). Clinical outcomes were analyzed using conditional logistic regression. Changes in PROs were analyzed using a mixed-effects model., Results: Five hundred and forty patients (52.6% normal BMD, 32.9% OPE, 14.4% OP-T) were included. In the unmatched cohort, 2-year reoperation rates (odds ratio [OR] = 0.45 [95% confidence interval (CI): 0.20 to 0.91]) and pseudarthrosis rates (OR = 0.25 [95% CI: 0.08 to 0.61]) were significantly lower in the OP-T group than the OPE group. Seventy-eight patients in the OP-T group were matched to 156 patients in the OPE group. Among these matched patients, at 2 years, 23.1% (36) in the OPE group versus 11.5% (9) in the OP-T group had a reoperation (OR = 0.45, p = 0.0188), 21.8% (34) versus 6.4% (5) had pseudarthrosis with or without implant failure (OR = 0.25, p = 0.0048), and 6.4% (10) versus 7.7% (6) had PJK (OR = 1.18, p = 0.7547), respectively. At 2 years postoperatively, PROs were better among OP-T patients than OPE patients. Subsequently, 78 patients in the OP-T group were matched to 156 patients in the normal BMD group. Among these matched patients, there was no significant difference in 2-year reoperation (OR = 0.85 [95% CI: 0.37 to 1.98]), pseudarthrosis (OR = 0.51 [95% CI: 0.181 to 1.44]), and PJK rates (OR = 0.77 [95% CI: 0.28 to 2.06)., Conclusions: Osteoporotic patients on teriparatide demonstrated lower reoperation and symptomatic pseudarthrosis rates 2 years postoperatively compared with osteopenic patients. Moreover, patient-reported and clinical outcomes for osteoporotic patients on teriparatide were not different from those for patients with normal BMD., Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H766 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

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

Background: Despite tremendous efforts, the incidence of surgical site infection (SSI) following the surgical treatment of pediatric spinal deformity remains a concern. Although previous studies have reported some risk factors for SSI, these studies have been limited by not being able to investigate multiple risk factors at the same time. The aim of the present study was to evaluate a wide range of preoperative and intraoperative factors in predicting SSI and to develop and validate a prediction model that quantifies the risk of SSI for individual pediatric spinal deformity patients., Methods: Pediatric patients with spinal deformity who underwent primary, revision, or definitive spinal fusion at 1 of 7 institutions were included. Candidate predictors were known preoperatively and were not modifiable in most cases; these included 31 patient, 12 surgical, and 4 hospital factors. The Centers for Disease Control and Prevention definition of SSI within 90 days of surgery was utilized. Following multiple imputation and multicollinearity testing, predictor selection was conducted with use of logistic regression to develop multiple models. The data set was randomly split into training and testing sets, and fivefold cross-validation was performed to compare discrimination, calibration, and overfitting of each model and to determine the final model. A risk probability calculator and a mobile device application were developed from the model in order to calculate the probability of SSI in individual patients., Results: A total of 3,092 spinal deformity surgeries were included, in which there were 132 cases of SSI (4.3%). The final model achieved adequate discrimination (area under the receiver operating characteristic curve: 0.76), as well as calibration and no overfitting. Predictors included in the model were nonambulatory status, neuromuscular etiology, pelvic instrumentation, procedure time ≥7 hours, American Society of Anesthesiologists grade >2, revision procedure, hospital spine surgical cases <100/year, abnormal hemoglobin level, and overweight or obese body mass index., Conclusions: The risk probability calculator encompassing patient, surgical, and hospital factors developed in the present study predicts the probability of 90-day SSI in pediatric spinal deformity surgery. This validated calculator can be utilized to improve informed consent and shared decision-making and may allow the deployment of additional resources and strategies selectively in high-risk patients., 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/JBJS/G814)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: As part of a market-driven response to the increasing costs of hospital-based surgical care, an increasing volume of orthopaedic procedures are being performed in ambulatory surgery centers (ASCs). The purpose of the present study was to identify recent trends in orthopaedic ASC procedure volume, utilization, and reimbursements in the Medicare system between 2012 and 2017., Methods: This cross-sectional, national study tracked annual Medicare claims and payments and aggregated data at the county level. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates, and reimbursement rates, and to identify demographic predictors of ASC utilization., Results: A total of 1,914,905 orthopaedic procedures were performed at ASCs in the Medicare population between 2012 and 2017, with an 8.8% increase in annual procedure volume and a 10.5% increase in average reimbursements per case. ASC orthopaedic procedure utilization, including utilization across all subspecialties, is strongly associated with metropolitan areas compared with rural areas. In addition, orthopaedic procedure utilization, including for sports and hand procedures, was found to be significantly higher in wealthier counties (measured by average household income) and in counties located in the South., Conclusions: This study demonstrated increasing orthopaedic ASC procedure volume in recent years, driven by increases in hand procedure volume. Medicare reimbursements per case have steadily risen and outpaced the rate of inflation over the study period. However, as orthopaedic practice overhead continues to increase, other Medicare expenditures such as hospital payments and operational and implant costs also must be evaluated. These findings may provide a source of information that can be used by orthopaedic surgeons, policy makers, investors, and other stakeholders to make informed decisions regarding the costs and benefits of the use of ASCs for orthopaedic procedures., Competing Interests: Disclosure: The authors indicated that no external funding was received for any aspect of this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work (http://links.lww.com/JBJS/G441)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: The selection of the lowest instrumented vertebra (LIV) in patients with adolescent idiopathic scoliosis (AIS) is still controversial. Although multiple radiographic methods have been proposed, there is no universally accepted guideline for appropriate selection of the LIV. We developed a simple and reproducible method for selection of the LIV in patients with Lenke type-1 (main thoracic) and 2 (double thoracic) curves and investigated its effectiveness in producing optimal positioning of the LIV at 5 years of follow-up., Methods: The radiographs for 299 patients with Lenke type-1 or 2 AIS curves that were included in a multicenter database were evaluated after a minimum duration of follow-up of 5 years. The "touched vertebra" (TV) was selected on preoperative radiographs by 2 independent examiners. The LIV on postoperative radiographs was compared with the preoperative TV. The final LIV position in relation to the center sacral vertical line (CSVL) was assessed. The CSVL-LIV distance and coronal balance in patients who had fusion to the TV were compared with those in patients who had fusion cephalad and caudad to the TV. The sagittal plane was also reviewed., Results: In 86.6% of patients, the LIV was selected at or immediately adjacent to the TV. Among patients with an "A" lumbar modifier, those who had fusion cephalad to the TV had a significantly greater CSVL-LIV distance than those who had fusion to the TV (p = 0.006) or caudad to the TV (p = 0.002). In the groups with "B" (p = 0.424) and "C" (p = 0.326) lumbar modifiers, there were no differences among the TV groups., Conclusions: We recommend the TV rule as a third modifier in the Lenke AIS classification system. Selecting the TV as the LIV in patients with Lenke type-1 and 2 curves provides acceptable positioning of the LIV at long-term follow-up. The position of the LIV was not different when fusion was performed caudad to the TV but came at the expense of fewer motion segments. Patients with lumbar modifier "A" who had fusion cephalad to the TV had greater translation of the LIV, putting these patients at risk for poor long-term outcomes., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: Cervical alignment is vital for maintaining horizontal gaze and sagittal balance. The aims of this study were to summarize previously published descriptions of normative cervical alignment and to analyze a cohort of asymptomatic volunteers in order to identify natural clusters of normal radiographic parameters., Methods: We performed a systematic review of the literature on radiographic measurements of asymptomatic volunteers through a search of MEDLINE and ScienceDirect databases. We then performed an analysis of demographic and radiographic parameters of volunteers without back or neck complaints. Only subjects with a chin-brow vertical angle (CBVA) within previously published normal limits were retained for analysis. A 2-step cluster analysis was used to find natural groups of cervical alignment. Differences among groups were investigated with a post hoc analysis of variance (ANOVA)., Results: We included 37 articles in our analysis. There was a broad spectrum of both C2-C7 lordosis-kyphosis and T1 slope across ages and sexes. Of the 119 asymptomatic volunteers who were available for analysis, 84 (with a mean age [and standard deviation] of 49.0 ± 17.1 years) had a CBVA ranging from -4.7° to 17.7°. The cluster analysis identified 3 alignment groups based on cervical lordosis-kyphosis and T1 slope (silhouette measure of cohesion, >0.6). Twenty-seven volunteers (32.1%) were identified as the "kyphotic curve cohort" (KCC) (mean C2-C7 Cobb angle, -8.6° ± 7.3°; mean T1 slope, 17.4° ± 6.6°), 43 volunteers (51.2%) were identified as the "medium lordosis cohort" (MLC) (mean C2-C7 Cobb angle, 8.7° ± 7.2°; mean T1 slope, 26.6° ± 4.0°), and 14 volunteers (16.7%) were identified as the "large lordosis cohort" (LLC) (mean C2-C7 Cobb angle, 21.2° ± 7.2°, mean T1 slope, 39.5° ± 6.4°) (p < 0.001 for both). Moving from KCC to LLC, there was a significant decrease in C0-C2 lordosis (p = 0.016). Examination of the cervical vertebral orientation demonstrated that C4 had a constant orientation relative to the horizontal (p = 0.665). Correlation analysis between C2-C7 and vertebral orientations again demonstrated that C4 orientation was independent of C2-C7 alignment., Conclusions: We have identified 3 morphotypes of the cervical spine based on C2-C7 alignment and T1 slope. These findings demonstrate the broad definition of normal cervical alignment and the range of cervical lordosis-kyphosis that is acceptable.

Background: Spine surgery training in the United States currently involves residency training in neurological or orthopaedic surgery. Because of different core residency surgical requirements, the volume of spine surgery procedures may vary between the 2 residencies., Methods: We reviewed the Accreditation Council for Graduate Medical Education resident case logs for both orthopaedic surgery and neurological surgery for exposure to spine surgery procedures for the graduating years of 2009 to 2018., Results: The average number of spine surgery procedures performed during that 10-year period was 433.8 for neurosurgery residents and 119.5 for orthopaedic surgery residents (p < 0.01). From 2009 to 2018, neurosurgery residents saw an increase of 26.5% in spine surgery procedures (from 389.6 to 492.9 procedures), whereas orthopaedic surgery residents saw a decrease of 41.3% (from 141.1 to 82.8 procedures). The 10-year average percentage of total spine procedures among all total surgical cases was 33.5% for neurosurgery residents compared with 6.2% for orthopaedic surgery residents (p < 0.01). This percentage decreased for both neurosurgery residents (35.8% in 2009 to 31.3% in 2018) and orthopaedic surgery residents (7.2% in 2009 to 4.9% in 2018). Neurosurgical residents performed 3.6 times more total spine procedures than orthopaedic surgery residents on average, a number that increased from 2.8-fold in 2009 to 6.0-fold in 2018., Conclusions: The case volume of spine surgery procedures varies greatly, with higher rates for neurological surgery and lower rates for orthopaedic surgery residencies, with an increasing discrepancy over time. Although case volume alone cannot solely determine quality of training, it is one measure to assess opportunities to develop optimal spine education around a certain accepted volume of surgical patient care. Not accounted for here are additional postgraduate spine cases performed by orthopaedic surgery residents who pursue spine fellowship training (an additional 300 to 500 cases). The results described herein may help to explore the various needs of and differences between residents seeking to pursue careers in spine as well as the role of spine surgery fellowships currently and in the future.

Background: The effectiveness of operative compared with nonoperative treatment at initial presentation (no prior fusion) for adult lumbar scoliosis has not, to our knowledge, been evaluated in controlled trials. The goals of this study were to evaluate the effects of operative and nonoperative treatment and to assess the benefits of these treatments to help treating physicians determine whether patients are better managed operatively or nonoperatively., Methods: Patients with adult symptomatic lumbar scoliosis (aged 40 to 80 years, with a coronal Cobb angle measurement of ≥30° and an Oswestry Disability Index [ODI] score of ≥20 or Scoliosis Research Society [SRS]-22 score of ≤4.0) from 9 North American centers were enrolled in concurrent randomized or observational cohorts to evaluate operative versus nonoperative treatment. The primary outcomes were differences in the mean change from baseline in the SRS-22 subscore and ODI at 2-year follow-up. For the randomized cohort, the initial sample-size calculation estimated that 41 patients per group (82 total) would provide 80% power with alpha equal to 0.05, anticipating 10% loss to follow-up and 20% nonadherence in the nonoperative arm. However, an interim sample-size calculation estimated that 18 patients per group would be sufficient., Results: Sixty-three patients were enrolled in the randomized cohort: 30 in the operative group and 33 in the nonoperative group. Two hundred and twenty-three patients were enrolled in the observational cohort: 112 in the operative group and 111 in the nonoperative group. The intention-to-treat analysis of the randomized cohort found that, at 2 years of follow-up, outcomes did not differ between the groups. Nonadherence was high in the randomized cohort (64% nonoperative-to-operative crossover). In the as-treated analysis of the randomized cohort, operative treatment was associated with greater improvement at the 2-year follow-up in the SRS-22 subscore (adjusted mean difference, 0.7 [95% confidence interval (CI), 0.5 to 1.0]) and in the ODI (adjusted mean difference, -16 [95% CI, -22 to -10]) (p < 0.001 for both). Surgery was also superior to nonoperative care in the observational cohort at 2 years after treatment on the basis of SRS-22 subscore and ODI outcomes (p < 0.001). In an overall responder analysis, more operative patients achieved improvement meeting or exceeding the minimal clinically important difference (MCID) in the SRS-22 subscore (85.7% versus 38.7%; p < 0.001) and the ODI (77.4% versus 38.3%; p < 0.001). Thirty-four revision surgeries were performed in 24 (14%) of the operative patients., Conclusions: On the basis of as-treated and MCID analyses, if a patient with adult symptomatic lumbar scoliosis is satisfied with current spine-related health, nonoperative treatment is advised, with the understanding that improvement is unlikely. If a patient is not satisfied with current spine health and expects improvement, surgery is preferred., Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Background: The reported neurologic complication rate following surgery for complex adult spinal deformity (ASD) is variable due to several factors. Most series have been retrospective with heterogeneous patient populations and use of nonuniform neurologic assessments. The aim of this study was to prospectively document lower extremity motor function by means of the American Spinal Injury Association (ASIA) lower extremity motor score (LEMS) before and through 2 years after surgical correction of complex ASD., Methods: The Scoli-RISK-1 study enrolled 272 patients with ASD, from 15 centers, who had undergone primary or revision surgery for a major Cobb angle of ≥80°, corrective osteotomy for congenital spinal deformity or as a revision procedure for any type of deformity, and/or a complex 3-column osteotomy., Results: One of 272 patients lacked preoperative data and was excluded from the analysis, and 62 (22.9%) of the remaining 271 patients, who were included, lacked a 2-year postoperative assessment. Patients with no preoperative motor impairment (normal LEMS group; n = 203) had a small but significant decline from the mean preoperative LEMS value (50) to that at 2 years postoperatively (49.66 [95% confidence interval = 49.46 to 49.85]; p = 0.002). Patients who did have a motor deficit preoperatively (n = 68; mean LEMS, 43.79) had significant LEMS improvement at 6 months (47.21, p < 0.001) and 2 years (46.12, p = 0.003) postoperatively. The overall percentage of patients (in both groups combined) who had a postoperative LEMS decline, compared with the preoperative value, was 23.0% at discharge, 17.1% at 6 weeks, 9.9% at 6 months, and 10.0% at 2 years., Conclusions: The percentage of patients who had a LEMS decline (compared with the preoperative score) after undergoing complex spinal reconstructive surgery for ASD was 23.0% at discharge, which improved to 10.0% at 2 years postoperatively. These rates are higher than previously reported, which we concluded was due to the prospective, strict nature of the LEMS testing of patients with these challenging deformities., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Short-term studies have shown improved outcomes and alignment after posterior vertebral column resection for severe spinal deformity. Our goal was to report long-term changes in radiographic and health-related quality-of-life measures in a consecutive series of pediatric and adult patients undergoing posterior vertebral column resection with a minimum follow-up of 5 years., Methods: We reviewed all patients undergoing posterior vertebral column resection by a single surgeon prior to January 1, 2010, at a single institution. Standard preoperative and perioperative data were collected, including the Scoliosis Research Society (SRS)-22/24 instrument. Radiographic and health-related quality-of-life measures changes were evaluated at a minimum follow-up of 5 years., Results: One hundred and nine patients underwent posterior vertebral column resection prior to January 2010, and 54 patients (49.5%) were available for analysis: 31 (57.4%) were pediatric patients, and 23 (42.6%) were adult patients. The mean age (and standard deviation) was 12.5 ± 3 years for the pediatric cohort and 39.3 ± 20 years for the adult cohort. Improvements in the mean major Cobb angle at a minimum follow-up of 5 years were seen: 61.6% correction for the pediatric cohort and 53.9% correction for the adult cohort. The rates of proximal junctional kyphosis, defined as proximal junctional kyphosis of >10°, were 16.1% for the pediatric cohort and 34.8% for the adult cohort, but none underwent a revision surgical procedure for symptomatic proximal junctional kyphosis. Of the 54 patients, 30 (55.6%) sustained complications, 5 (9.3%) experienced postoperative neurological deficits, and 7 (13.0%) required a revision by 5 years postoperatively. Significant improvements were observed in the SRS-Self Image with regard to the pediatric cohort at 0.9 (p = 0.017) and the adult cohort at 1.3 (p = 0.002) and in the SRS-Satisfaction with regard to the pediatric cohort at 1.8 (p = 0.008) and the adult cohort at 1.3 (p = 0.005)., Conclusions: Posterior vertebral column resection offers substantial, sustained improvements in global radiographic alignment and patient outcome scores at 5 years. The major radiographic deformity was reduced by 61.6% in the pediatric cohort and by 53.9% in the adult cohort. Despite the high rate of complications, patients experienced significant improvement in the SRS-Self Image and SRS-Satisfaction domains., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Spinopelvic fixation is an integral part of achieving solid fusion across the lumbosacral junction, especially in deformity procedures requiring substantial correction or long-segment constructs. Traditional S2-alar-iliac (S2AI) screw-placement techniques utilize fluoroscopy, increasing operative time and radiation exposure to the patient and surgeon. We describe a novel free-hand technique for S2AI screw placement in patients with adult spinal deformity., Methods: We reviewed the records of 45 consecutive patients who underwent spinopelvic fixation performed with use of S2AI screws by the senior surgeon and various fellows or residents over a 12-month period (2015 to 2016). In each case, the S2AI screws were placed utilizing a free-hand technique without fluoroscopic or image guidance. Screw position and accuracy were assessed by intraoperative O-arm imaging and analyzed using 3-dimensional interactive manipulation of computed tomography images., Results: A total of 100 screws were placed, 51 by the senior surgeon and 49 by trainees. The mean patient age was 57.4 ± 12.7 years at the time of surgery; 37 (82.2%) of the patients were female. Preoperative diagnoses included adult idiopathic scoliosis (n = 19), adult degenerative scoliosis (n = 15), flatback syndrome (n = 2), fixed sagittal imbalance (n = 6), and distal junctional kyphosis (n = 3). Five (5%) of the screws were placed with moderate to severe cortical breaches, all of which perforated the pelvis posteriorly, with no clinically notable neurovascular or visceral complications. The breach rate did not differ significantly between the senior surgeon and trainees., Conclusions: The free-hand technique for S2AI screw placement, when performed in a standardized manner, was demonstrated to be safe and reliable in constructs requiring spinopelvic fixation. The accuracy of screw placement relies on visible and palpable anatomic landmarks that obviate the need for intraoperative fluoroscopy or image guidance, potentially reducing operative time and radiation exposure., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Scoliosis is a feature of several genetic disorders that are also associated with aortic aneurysm, including Marfan syndrome, Loeys-Dietz syndrome, and type-IV Ehlers-Danlos syndrome. Life-threatening complications of aortic aneurysm can be decreased through early diagnosis. Genetic screening for mutations in populations at risk, such as patients with adolescent idiopathic scoliosis, may improve recognition of these disorders., Methods: The coding regions of five clinically actionable genes associated with scoliosis (COL3A1, FBN1, TGFBR1, TGFBR2, and SMAD3) and aortic aneurysm were sequenced in 343 adolescent idiopathic scoliosis cases. Gene variants that had minor allele frequencies of <0.0001 or were present in human disease mutation databases were identified. Variants were classified as pathogenic, likely pathogenic, or variants of unknown significance., Results: Pathogenic or likely pathogenic mutations were identified in 0.9% (three) of 343 adolescent idiopathic scoliosis cases. Two patients had pathogenic SMAD3 nonsense mutations consistent with type-III Loeys-Dietz syndrome and one patient had a pathogenic FBN1 mutation with subsequent confirmation of Marfan syndrome. Variants of unknown significance in COL3A1 and FBN1 were identified in 5.0% (seventeen) of 343 adolescent idiopathic scoliosis cases. Six FBN1 variants were previously reported in patients with Marfan syndrome, yet were considered variants of unknown significance based on the level of evidence. Variants of unknown significance occurred most frequently in FBN1 and were associated with greater curve severity, systemic features of Marfan syndrome, and joint hypermobility., Conclusions: Clinically actionable pathogenic mutations in genes associated with adolescent idiopathic scoliosis and aortic aneurysm are rare in patients with adolescent idiopathic scoliosis who are not suspected of having these disorders, although variants of unknown significance are relatively common., Clinical Relevance: Routine genetic screening of all patients with adolescent idiopathic scoliosis for mutations in clinically actionable aortic aneurysm disease genes is not recommended on the basis of the high frequency of variants of unknown significance. Clinical evaluation and family history should heighten indications for genetic referral and testing., (Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: The literature regarding pulmonary function in adult patients with spinal deformity is limited, and the effect of spinal deformity surgery on pulmonary function has not been clearly understood. We hypothesized that adult patients with spinal deformity who had preoperative pulmonary impairment (a percent-predicted value of <65% forced expiratory volume in one second [FEV1] as measured by pulmonary function test) or who were undergoing revision surgery may be at risk for exacerbated decline in pulmonary function., Methods: Pulmonary function test results were prospectively collected for 164 adult patients with spinal deformity (mean age, 45.9 years) who underwent surgical treatment at a single institution and were followed for a minimum of two years (mean, 2.8 years). One hundred (61%) of the patients underwent primary surgery, and sixty-four (39%) of the patients had revision surgery. For the majority of patients (77%), a posterior-only surgical approach was used. Radiographs for 154 patients were analyzed for major thoracic and sagittal T5-T12 curve magnitude/correction., Results: For all patients, we noted a significant change in major thoracic Cobb angle, from a mean of 47.4° to 24.9°(p < 0.001), and in sagittal Cobb angle, from a mean of 35.5° to 30.0°(p < 0.001), as well as a significant decline in absolute and percent-predicted pulmonary function values, with percent-predicted FEV1 and percent-predicted forced vital capacity (FVC) decreasing 5.3% (p < 0.001) and 5.7% (p < 0.001), respectively. A clinically significant decline (a decline of ≥10% in percent-predicted FEV1) was observed in 27% of the patients. The number of patients with pulmonary impairment increased nonsignificantly from seventeen (10%) preoperatively to twenty-three (14%) after surgery (p = 0.31). Patients with preoperative pulmonary impairment demonstrated a significant improvement in absolute and percent-predicted FEV1 after surgery compared with those without preoperative impairment (2.7% compared with -6.2%; p < 0.001). Patients who underwent revision surgery did not differ from primary surgery patients in terms of postoperative percent-predicted results. However, revision surgery more frequently resulted in a significant decline in pulmonary function (twenty-three patients [36%] compared with twenty-two [22%]; p = 0.05). There was no difference in pulmonary function when comparing surgical approaches (anterior/combined anterior-posterior or posterior-only) or when comparing results by upper-instrumented vertebra (UIV)., Conclusions: We found a significant decline in absolute and percent-predicted results of pulmonary function tests following surgical correction for spinal deformity in adults., (Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Surgical site infections are not uncommon following spinal operations, and they can be associated with serious morbidity, mortality, and increased resource utilization. The accurate identification of risk factors is essential to develop strategies to prevent these potentially devastating infections. We conducted a case-control study to determine independent risk factors for surgical site infection following orthopaedic spinal operations., Methods: We performed a retrospective case-control study of patients who had had an orthopaedic spinal operation performed at a university-affiliated tertiary-care hospital from 1998 to 2002. Forty-six patients with a superficial, deep, or organ-space surgical site infection were identified and compared with 227 uninfected control patients. Risk factors for surgical site infection were determined with univariate analyses and multivariate logistic regression., Results: The overall rate of spinal surgical site infection during the five years of the study was 2.0% (forty-six of 2316). Univariate analyses showed serum glucose levels, preoperatively and within five days after the operation, to be significantly higher in patients in whom surgical site infection developed than in uninfected control patients. Independent risk factors for surgical site infection that were identified by multivariate analysis were diabetes (odds ratio = 3.5, 95% confidence interval = 1.2, 10.0), suboptimal timing of prophylactic antibiotic therapy (odds ratio = 3.4, 95% confidence interval = 1.5, 7.9), a preoperative serum glucose level of >125 mg/dL (>6.9 mmol/L) or a postoperative serum glucose level of >200 mg/dL (>11.1 mmol/L) (odds ratio = 3.3, 95% confidence interval = 1.4, 7.5), obesity (odds ratio = 2.2, 95% confidence interval = 1.1, 4.7), and two or more surgical residents participating in the operative procedure (odds ratio = 2.2, 95% confidence interval = 1.0, 4.7). A decreased risk of surgical site infection was associated with operations involving the cervical spine (odds ratio = 0.3, 95% confidence interval = 0.1, 0.6)., Conclusions: Diabetes was associated with the highest independent risk of spinal surgical site infection, and an elevated preoperative or postoperative serum glucose level was also independently associated with an increased risk of surgical site infection. The role of hyperglycemia as a risk factor for surgical site infection in patients not previously diagnosed with diabetes should be investigated further. Administration of prophylactic antibiotics within one hour before the operation and increasing the antibiotic dosage to adjust for obesity are also important strategies to decrease the risk of surgical site infection after spinal operations.

Background: The reported prevalence of non-neurologic complications following corrective surgery for adolescent idiopathic scoliosis ranges from 0% to 10%. However, most studies were retrospective evaluations of treatment techniques and did not focus solely on complications. The purpose of this study was to determine the prevalence of non-neurologic complications following surgery for adolescent idiopathic scoliosis and to identify preoperative and operative factors that can increase this risk., Methods: The demographic data, medical and surgical histories, and prevalence of non-neurologic complications were reviewed in a prospective cohort of 702 patients who had undergone corrective surgery for adolescent idiopathic scoliosis and were consecutively enrolled in a multicenter database., Results: There were 556 female and 146 male patients. The mean age at the time of surgery was 14.25 years (range, eight to eighteen years). Five hundred and twenty-three patients had only posterior spinal surgery, 105 had only anterior spinal surgery, and seventy-four had a combined anterior and posterior procedure. There was a total of 108 complications in eighty-one patients, for an overall prevalence of 15.4%. There were ten respiratory complications (1.42%), six cases of excessive bleeding (0.85%), five wound infections (0.71%), and five cases of wound hematoma, seroma, or dehiscence (0.71%). Five patients, two with an early infection and three with late failure of the implant, required a reoperation. Factors that did not correlate with an increased prevalence of complications were age, body mass index, presence of cardiac or respiratory disease, previous surgery, pulmonary function, surgical approach, number of levels fused, graft material, use of a diaphragmatic incision, Lenke curve type, or region of the major curve. Although the number of patients with renal disease was small, these patients were 7.90 times more likely to have a non-neurologic complication. Increased blood loss as well as prolonged operative and anesthesia times were associated with a higher prevalence of non-neurologic complications., Conclusions: The prevalence of non-neurologic postoperative complications following surgery for correction of adolescent idiopathic scoliosis in this study was 15.4%. The few factors noted to significantly increase the rate of complications include a history of renal disease, increased operative blood loss, prolonged posterior surgery time, and prolonged anesthesia time.

Background: In a previous prospective, randomized, controlled, double-blinded study on the effect of nerve root blocks on the need for operative treatment of lumbar radicular pain, we found that injections of corticosteroids were more effective than bupivacaine for up to thirteen to twenty-eight months. We performed a minimum five-year followup of those patients who had avoided surgery., Methods: All of the patients were considered to be operative candidates by the treating surgeon, and all had initially requested operative intervention. They had then been randomized to be treated with a selective nerve-root block with either bupivacaine or bupivacaine and betamethasone. Both the treating physician and the patient were blinded to the type of medication. Of fifty-five randomized patients, twenty-nine avoided an operation in the original study. Twenty-one of those twenty-nine patients were reevaluated with a follow-up questionnaire at a minimum of five years after the initial block., Results: Seventeen of the twenty-one patients still had not had operative intervention. There was no difference between the group treated with bupivacaine alone and the group treated with bupivacaine and betamethasone with regard to the avoidance of surgery for five years. At the five-year follow-up evaluation, all of the patients who had avoided operative treatment had significant decreases in neurological symptoms and back pain compared with the baseline values., Conclusions: The majority of patients with lumbar radicular pain who avoid an operation for at least one year after receiving a nerve root injection with bupivacaine alone or in combination with betamethasone will continue to avoid operative intervention for a minimum of five years.

Background: There have been few detailed reports concerning pseudarthrosis following spinal instrumentation and arthrodesis in adults with spinal deformity since the introduction of modern segmental fixation techniques. The purposes of this study were to analyze the prevalence, risk factors, and outcome scores on the Scoliosis Research Society Instrument-24 associated with pseudarthrosis following instrumentation and arthrodesis for the treatment of spinal deformity in adults., Methods: A clinical and radiographic assessment of 232 adults with spinal deformity who were treated surgically at a single institution was conducted. The average age of the patients was 40.8 years, and the operation was a primary procedure in 150 patients and a revision procedure in eighty-two patients. All patients who underwent a long (four vertebrae or more) spinal instrumentation and arthrodesis with a minimum follow-up of two years were included in the analysis. Clinical outcomes were assessed with the Scoliosis Research Society questionnaire., Results: Forty patients had a pseudarthrosis. Factors that were found to be significantly associated with pseudarthrosis were preoperative thoracolumbar kyphosis of >20 degrees (p < 0.0001), an age of more than fifty-five years (p = 0.001), arthrodesis to S1 compared with arthrodesis to L5 or a cephalad level (p = 0.002), and arthrodesis of more than twelve vertebrae (p = 0.037). Patients with a pseudarthrosis had lower total outcome scores on the Scoliosis Research Society questionnaire, on the average, than those without a pseudarthrosis (p = 0.001)., Conclusions: The prevalence of pseudarthrosis following long arthrodesis with use of modern segmental spinal instrumentation for the treatment of spinal deformity in adults was 17%, and the clinical outcome in these patients can be negatively affected by the pseudarthrosis.

Background: Previous research has suggested a correlation between pulmonary impairment and thoracic spinal deformity. The curve magnitude, number of involved vertebrae, curve location, and decrease in thoracic kyphosis independently contribute to pulmonary impairment, but the strength of these associations has been variable. The objectives of this study were to test the hypothesis that increased thoracic deformity is associated with decreased pulmonary function and to determine which, if any, radiographic measurements of deformity predict pulmonary impairment., Methods: Preoperative pulmonary function testing and radiographic examination were performed on 631 patients with adolescent idiopathic scoliosis. Correlation analysis and subsequent stepwise multiple regression analysis were carried out to assess the associations between radiographic measurements of deformity and the results of pulmonary function testing., Results: The magnitude of the thoracic curve, the number of vertebrae involved in the thoracic curve, the thoracic hypokyphosis, and coronal imbalance had a minimal but significant effect on pulmonary function. While these four factors were associated with an increased risk of moderate or severe pulmonary impairment, they explained only 19.7%, 18.0%, and 8.8% of the observed variability in forced vital capacity, forced expiratory volume in one second, and total lung capacity, respectively. The degrees of scoliosis that were associated with clinically relevant decreases in pulmonary function were much smaller than previously described, but the majority of the observed variability in pulmonary function was not explained by the radiographic characteristics of the deformity., Conclusions: Some patients with adolescent idiopathic scoliosis may have clinically relevant pulmonary impairment that is out of proportion with the severity of the scoliosis, and this may alter the decision-making process regarding which fusion technique will produce an acceptable clinical result with the least additional effect on pulmonary function.

Background: The long-term pulmonary function of patients with adolescent idiopathic scoliosis undergoing surgical correction is uncertain. To our knowledge, no report has demonstrated the changes in pulmonary function five years or more following spinal arthrodesis with use of modern segmental spinal instrumentation techniques for the treatment of all types of adolescent idiopathic scoliosis in a similar adolescent population., Methods: One hundred and eighteen patients with adolescent idiopathic scoliosis undergoing surgical treatment at a single institution were evaluated with pulmonary function tests to assess the absolute and percent-predicted value of forced vital capacity and forced expiratory volume in one second at the preoperative examination and at regular intervals postoperatively. The patients were divided into four groups depending upon the surgical procedure: Group 1 comprised forty-nine patients who had posterior spinal arthrodesis with iliac crest bone graft; Group 2, forty-one patients who had posterior spinal arthrodesis with thoracoplasty; Group 3, sixteen patients who had open anterior spinal arthrodesis with a rib resection thoracotomy; and Group 4, twelve patients who had combined anterior and posterior spinal arthrodesis with a rib resection thoracotomy and iliac crest bone graft, respectively., Results: A comparison of absolute pulmonary function values from the preoperative and final follow-up evaluations demonstrated a significant (p < 0.0001) increase in both the forced vital capacity and the forced expiratory volume in one second for Group 1, whereas no change was seen in those values for Groups 2, 3, and 4. A comparison of the changes in the percent-predicted pulmonary function values demonstrated significant (p < 0.05) decreases in forced vital capacity and forced expiratory volume in one second for Groups 2, 3, and 4, except for the latter value for Group 4, whereas Group 1 had no change., Conclusions: Patients who have had any type of chest cage disruption during the surgical treatment of adolescent idiopathic scoliosis demonstrate no change in the absolute value and a significant decline in the percent-predicted value of pulmonary functions at five years following surgery. Chest cage preservation is recommended to maximize both absolute and percent-predicted pulmonary function values after surgical treatment of adolescent idiopathic scoliosis.

The most common cause of iatrogenic flatback syndrome is Harrington distraction instrumentation extending into the lower lumbar spine. Other common causes and exacerbating factors include failure to enhance regional lordosis during lumbar fusion for degenerative spondylosis, development of pseudarthrosis or postoperative loss of correction, development of kyphosis at the thoracolumbar junction, development of degeneration and decompensation cephalad or caudad to a prior fusion, and hip flexion contractures. Prevention of flatback syndrome involves preoperative assessment of sagittal balance, avoidance of distraction instrumentation and extension of long fusions into the lower lumbar spine, enhancement of physiologic lordosis during lumbar fusions, and intraoperative positioning with the hips extended. Treatment of flatback syndrome involves corrective pedicle subtraction or Smith-Petersen osteotomies with segmental instrumentation. Polysegmental osteotomies and vertebral column resection may be utilized in cases of sloping global sagittal imbalance and related severe coronal imbalance, respectively. Following surgical treatment, sagittal balance is generally improved with fair-to-good clinical outcomes, high patient satisfaction, and moderately high perioperative complication rates.

Background: Fixed sagittal imbalance (a syndrome in which the patient is only able to stand with the weight-bearing line in front of the sacrum) has many etiologies. The most commonly reported technique for correction is the Smith-Petersen osteotomy. Few reports on pedicle subtraction procedures (resection of the posterior elements, pedicles, and vertebral body through a posterior approach) are available in the peer-reviewed literature. We are aware of no report involving a substantial number of patients with coexistent scoliosis who underwent pedicle/vertebral body subtraction for the treatment of fixed sagittal imbalance., Methods: Twenty-seven consecutive patients in whom sagittal imbalance was treated with lumbar pedicle subtraction osteotomy at one institution were analyzed. Radiographic analysis included assessment of thoracic kyphosis, lumbar lordosis, lordosis through the pedicle subtraction osteotomy site, and the C7 sagittal plumb line. Outcomes analysis was performed with use of a before-and-after pain scale, items from the Oswestry questionnaire, and the Scoliosis Research Society (SRS) questionnaire after a minimum duration of follow-up of two years. Complications and radiographic findings were also analyzed for the entire group., Results: Overall, the average increase in lordosis was 34.1 degrees and the average improvement in the sagittal plumb line was 13.5 cm. One patient had development of a lumbar pseudarthrosis through the area of pedicle subtraction osteotomy, and six patients had development of a thoracic pseudarthrosis. Two patients had development of increased kyphosis at L5/S1, caudad to the fusion, resulting in some loss of sagittal correction. There were significant improvements in the overall Oswestry score (p < 0.0001) and the pain-scale score (p = 0.0002). Most patients reported improvement in terms of pain and self-image as well as overall satisfaction with the procedure., Conclusions: Pedicle subtraction osteotomy is a useful procedure for patients with fixed sagittal imbalance. A worse clinical result is associated with increasing patient comorbidities, pseudarthrosis in the thoracic spine, and subsequent breakdown caudad to the fusion.

Background: Fixed sagittal imbalance (a syndrome in which the patient is only able to stand with the weight-bearing line in front of the sacrum) has many etiologies. The most commonly reported technique for correction is the Smith-Petersen osteotomy. Few reports on pedicle subtraction procedures (resection of the posterior elements, pedicles, and vertebral body through a posterior approach) are available in the peer-reviewed literature. We are aware of no report involving a substantial number of patients with coexistent scoliosis who underwent pedicle/vertebral body subtraction for the treatment of fixed sagittal imbalance., Methods: Twenty-seven consecutive patients in whom sagittal imbalance was treated with lumbar pedicle subtraction osteotomy at one institution were analyzed. Radiographic analysis included assessment of thoracic kyphosis, lumbar lordosis, lordosis through the pedicle subtraction osteotomy site, and the C7 sagittal plumb line. Outcomes analysis was performed with use of a before-and-after pain scale, items from the Oswestry questionnaire, and the Scoliosis Research Society (SRS) questionnaire after a minimum duration of follow-up of two years. Complications and radiographic findings were also analyzed for the entire group., Results: Overall, the average increase in lordosis was 34.1 degrees and the average improvement in the sagittal plumb line was 13.5 cm. One patient had development of a lumbar pseudarthrosis through the area of pedicle subtraction osteotomy, and six patients had development of a thoracic pseudarthrosis. Two patients had development of increased kyphosis at L5/S1, caudad to the fusion, resulting in some loss of sagittal correction. There were significant improvements in the overall Oswestry score (p < 0.0001) and the pain-scale score (p = 0.0002). Most patients reported improvement in terms of pain and self-image as well as overall satisfaction with the procedure., Conclusions: Pedicle subtraction osteotomy is a useful procedure for patients with fixed sagittal imbalance. A worse clinical result is associated with increasing patient comorbidities, pseudarthrosis in the thoracic spine, and subsequent breakdown caudad to the fusion., Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Background: Although reports in the literature have demonstrated an approximately 20% prevalence of neural axis abnormalities in patients with juvenile idiopathic scoliosis who have a curve of >20 degrees, the prevalence of neural axis abnormalities in patients with infantile idiopathic scoliosis is not well documented. In two previous studies involving a total of only ten patients with infantile idiopathic scoliosis, five patients were noted to have a neural axis abnormality on magnetic resonance images., Methods: The records of forty-six consecutive patients who were seen between 1992 and 2000 at three spinal deformity clinics were retrospectively reviewed. The inclusion criteria included presumed idiopathic scoliosis at the time of presentation, an age of three years or less, a curve magnitude of > or = 20 degrees, normal neurological findings, no associated syndromes, and no congenital abnormalities. All patients were evaluated with a total spine magnetic resonance imaging protocol for examination of neural axis abnormalities from the skull to the coccyx., Results: Ten (21.7%) of the forty-six patients were found to have a neural axis abnormality on magnetic resonance imaging. This group included five patients with an Arnold-Chiari malformation and an associated cervicothoracic syrinx, three with syringomyelia, one with a low-lying conus, and one with a brainstem tumor. Eight of these ten patients needed neurosurgical intervention for treatment of the abnormality., Conclusions: The 21.7% prevalence of neural axis abnormalities in this group of patients with infantile idiopathic scoliosis was found to be almost identical to that reported in the literature on patients with juvenile idiopathic scoliosis. Because of the high prevalence of abnormalities and the fact that eight of the ten patients with abnormal findings on magnetic resonance images required neurosurgical intervention, a total spine magnetic resonance imaging evaluation at the time of presentation is recommended for all patients with infantile idiopathic scoliosis who have a curve measuring > or = 20 degrees.

Background: The relationship between objective measurements and subjective symptoms of patients with spinal stenosis and the degree of narrowing of the spinal canal is not clear. The purpose of this study was to evaluate patients undergoing surgery for lumbar spinal stenosis and intermittent neurogenic claudication with functional testing, quantitative imaging, and patient self-assessment., Methods: Sixty-two patients with lumbar spinal stenosis and neurogenic claudication were prospectively enrolled in the study. All underwent preoperative magnetic resonance imaging and/or computed tomography myelography, and all were treated with decompressive surgery and were followed for a minimum of two years. The evaluation included treadmill and bicycle exercise tests as well as patient self-assessment with use of the Oswestry Disability Index and a visual analog pain scale preoperatively and postoperatively., Results: Preoperatively fifty-eight (94%) of the patients had a positive result (provocation of symptoms) on the treadmill test and twenty-seven (44%) had a positive result on the bicycle test, whereas postoperatively six and twelve, respectively, had positive results. The mean preoperative scores on the Oswestry Disability Index and visual analog pain scale were 58.4 and 7.1, respectively. Postoperatively, these scores decreased to 21.1 and 2.3, respectively, and both decreases were significant (p < 0.05). Forty-seven (76%) of the patients were seen to have central stenosis on the preoperative imaging studies; forty-one of them had a cross-sectional area of the dural tube of <100 mm (2) at at least one level and twelve had a cross-sectional area of <100 mm (2) at at least two levels., Conclusions: A positive treadmill test was consistent with a diagnosis of spinal stenosis and neurogenic claudication in >90% of the patients preoperatively. Following surgical decompression of the lumbar spinal stenosis, more functional improvement was demonstrated by the treadmill test than by the bicycle test. The scores on the Oswestry Disability Index and visual analog pain scale also improved postoperatively. The severity of central canal narrowing at a single level does not appear to limit the postoperative improvement in either functional ability or patient self-assessment. Patients with multilevel central stenosis were, on the average, older and walked a shorter distance preoperatively and postoperatively, although the improvement in their postoperative self-assessment scores was similar to that of patients with single-level stenosis.

Background: The lack of a reliable, universally acceptable system for classification of adolescent idiopathic scoliosis has made comparisons between various types of operative treatment an impossible task. Furthermore, long-term outcomes cannot be determined because of the great variations in the description of study groups., Methods: We developed a new classification system with three components: curve type (1 through 6), a lumbar spine modifier (A, B, or C), and a sagittal thoracic modifier (-, N, or +). The six curve types have specific characteristics, on coronal and sagittal radiographs, that differentiate structural and nonstructural curves in the proximal thoracic, main thoracic, and thoracolumbar/lumbar regions. The lumbar spine modifier is based on the relationship of the center sacral vertical line to the apex of the lumbar curve, and the sagittal thoracic modifier is based on the sagittal curve measurement from the fifth to the twelfth thoracic level. A minus sign represents a curve of less than +10 degrees, N represents a curve of 10 degrees to 40 degrees, and a plus sign represents a curve of more than +40 degrees. Five surgeons, members of the Scoliosis Research Society who had developed the new system and who had previously tested the reliability of the King classification on radiographs of twenty-seven patients, measured the same radiographs (standing coronal and lateral as well as supine side-bending views) to test the reliability of the new classification. A randomly chosen independent group of seven surgeons, also members of the Scoliosis Research Society, tested the reliability and validity of the classification as well., Results: The interobserver and intraobserver kappa values for the curve type were, respectively, 0.92 and 0.83 for the five developers of the system and 0.740 and 0.893 for the independent group of seven scoliosis surgeons. In the independent group, the mean interobserver and intraobserver kappa values were 0.800 and 0.840 for the lumbar modifier and 0.938 and 0.970 for the sagittal thoracic modifier. These kappa values were all in the good-to-excellent range (>0.75), except for the interobserver reliability of the independent group for the curve type (kappa = 0.74), which fell just below this level., Conclusions: This new two-dimensional classification of adolescent idiopathic scoliosis, as tested by two groups of surgeons, was shown to be much more reliable than the King system. Additional studies are necessary to determine the versatility, reliability, and accuracy of the classification for defining the vertebrae to be included in an arthrodesis.

Background: The purpose of the present study was to determine the effectiveness of selective nerve-root injections in obviating the need for an operation in patients with lumbar radicular pain who were otherwise considered to be operative candidates. Although selective nerve-root injections are used widely, we are not aware of any prospective, randomized, controlled, double-blind studies demonstrating their efficacy., Methods: Fifty-five patients who were referred to four spine surgeons because of lumbar radicular pain and who had radiographic confirmation of nerve-root compression were prospectively randomized into the study. All of the patients had to have requested operative intervention and had to be considered operative candidates by the treating surgeon. They then were randomized and referred to a radiologist who performed a selective nerve-root injection with either bupivacaine alone or bupivacaine with betamethasone. The treating physicians and the patients were blinded to the medication. The patients were allowed to choose to receive as many as four injections. The treatment was considered to have failed if the patient proceeded to have the operation, which he or she could opt to do at any point in the study., Results: Twenty-nine of the fifty-five patients, all of whom had initially requested operative treatment, decided not to have the operation during the follow-up period (range, thirteen to twenty-eight months) after the nerve-root injections. Of the twenty-seven patients who had received bupivacaine alone, nine elected not to have the operation. Of the twenty-eight patients who had received bupivacaine and betamethasone, twenty decided not to have the operation. The difference in the operative rates between the two groups was highly significant (p < 0.004)., Conclusions: Our data demonstrate that selective nerve-root injections of corticosteroids are significantly more effective than those of bupivacaine alone in obviating the need for a decompression for up to thirteen to twenty-eight months following the injections in operative candidates. This finding suggests that patients who have lumbar radicular pain at one or two levels should be considered for treatment with selective nerve-root injections of corticosteroids prior to being considered for operative intervention.

The system described by King et al. is the standard method for the classification of thoracic adolescent idiopathic scoliosis. Although it is widely used and referenced, its reliability and reproducibility among scoliosis surgeons are unknown. We used a scoliosis case-presentation format to examine the interobserver and intraobserver reliability of the classification of thoracic adolescent idiopathic scoliosis with the system of King et al. Eight active, current members of the Scoliosis Research Society reviewed twenty-seven full-length radiographs that had been made before operative correction of the scoliotic deformity. On the basis of these images, which included posteroanterior and lateral radiographs made with the patient standing as well as right and left forced-side-bending radiographs made with the patient supine, the reviewers assigned a type to each curve according to the classification system of King et al. Kappa coefficients were used to test statistical reliability. The mean interobserver reliability of the classification was only 64 per cent (range, 54 to 77 per cent) when the responses of seven of the reviewers were compared with those of one of the originators of the classification. The mean kappa coefficient was 0.49 (range, 0.27 to 0.73), which indicates poor reliability. When each reviewer's responses were compared with those of the other reviewers, the reliability was similarly poor (interobserver reliability, 55 per cent [range, 33 to 81 per cent] and mean kappa coefficient, 0.40 [range, 0.21 to 0.63]). Intraobserver reliability was evaluated in a trial in which five reviewers in a group setting were shown the same radiographs in a different order at two different viewings. Comparison of the results at the two viewings revealed a mean intraobserver reliability of 69 per cent (range, 56 to 85 per cent) and a mean kappa coefficient of 0.62 (range, 0.34 to 0.95), which indicates fair reliability. The current method of classification of adolescent idiopathic scoliosis does not appear to have sufficient intraobserver or interobserver reliability among scoliosis surgeons to portray curve types accurately. Thus, it may not help to guide treatment with use of modern spinal fixation methods.

We evaluated the radiographic results of posterior spinal arthrodesis with use of Cotrel-Dubousset instrumentation in seventy-six patients who had adolescent idiopathic scoliosis. At an average of six years (range, five to ten years) postoperatively, the fusion appeared to be solid in all patients. Comparison of radiographs that had been made immediately postoperatively with those that had been made at the time of the latest follow-up showed that no patient had lost any correction in the coronal plane at the levels with instrumentation and seventy-five had had no change in the thoracic or lumbar sagittal alignment at the levels with or without instrumentation. In the remaining patient, a kyphosis had developed at the junction of the segments with instrumentation and those without instrumentation, necessitating additional operative treatment. Sixty-three patients completed a questionnaire for assessment of the clinical status. Their responses were favorable with regard to function, cosmetic appearance, and general satisfaction with the operative result. Twenty-four (38 per cent) of the sixty-three patients reported occasional pain in the spine that did not interfere with work or school activities. Sixty-two patients stated that, given the hypothetical situation of reverting to the preoperative status, they would have the operation again.

We evaluated the results of segmental fixation of the spine with Cotrel-Dubousset instrumentation in ninety-five patients who had adolescent idiopathic scoliosis. The instrumentation was used in an attempt to achieve three-dimensional correction of the scoliosis, maintain lumbar lordosis, create thoracic kyphosis, and avoid the need for a postoperative cast or brace. The patients were followed for twenty-four to sixty-four months (average, thirty-five months). Cotrel-Dubousset instrumentation provided an average correction of the coronal curve of 48 per cent at the time of the most recent follow-up. The normal sagittal curves at the thoracolumbar junction and in the lumbar spine were maintained, and the thoracic kyphosis was increased slightly (average, +7 degrees). Apical translation improved an average of 60 per cent, and apical rotation improved an average of 11 per cent. Forced vital capacity improved an average of 21 per cent, and the one-second forced expiratory volume improved an average of 18 per cent. There were no major neurological deficits. A symptomatic pseudarthrosis developed in one patient. Postoperatively, decompensation of the spine developed in five of the first twenty-six patients who had a Type-II or Type-III curve. This complication was avoided in the last twenty-four patients who had a Type-II or Type-III curve by means of a stricter adherence to the definition of a Type-II curve, and reversal of the bend of the rod and the hooks between the caudal neutral and stable vertebrae. The major advantages of Cotrel-Dubousset instrumentation are the stable fixation that is achieved and the preservation of segmental lumbar lordosis.