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Background: Thoracic anterior vertebral body tethering (TAVBT) is an emerging treatment for adolescent idiopathic scoliosis. Tether breakage is a known complication of TAVBT with incompletely known incidence. We aim to define the incidence of tether breakage in patients with adolescent idiopathic scoliosis who undergo TAVBT. The incidence of tether breakage in TAVBT is hypothesized to be high and increase with time postoperatively., Methods: All patients with right-sided, thoracic curves who underwent TAVBT with at least 2 and up to 3 years of radiographic follow-up were included. Tether breakage between 2 vertebrae was defined a priori as any increase in adjacent screw angle >5 degrees from the minimum over the follow-up period. The presence and timing of tether breakage were noted for each patient. A Kaplan-Meier survival analysis was performed to calculate expected tether breakage up to 36 months. χ 2 analysis was performed to examine the relationship between tether breakage and reoperations. Independent t test was used to compare the average final Cobb angle between cohorts., Results: In total, 208 patients from 10 centers were included in our review. Radiographically identified tether breakage occurred in 75 patients (36%). The initial break occurred at or beyond 24 months in 66 patients (88%). Kaplan-Meier survival analysis estimated the cumulative rate of expected tether breakage to be 19% at 24 months, increasing to 50% at 36 months. Twenty-one patients (28%) with a radiographically identified tether breakage went on to require reoperation, with 9 patients (12%) requiring conversion to posterior spinal fusion. Patients with a radiographically identified tether breakage went on to require conversion to posterior spinal fusion more often than those patients without identified tether breakage (12% vs. 2%; P =0.004). The average major coronal curve angle at final follow-up was significantly larger for patients with radiographically identified tether breakage than for those without tether breakage (31 deg±12 deg vs. 26 deg±12 deg; P =0.002)., Conclusions: The incidence of tether breakage in TAVBT is high, and it is expected to occur in 50% of patients by 36 months postoperatively., Level of Evidence: Level IV., Competing Interests: Compliance with Ethical Standards: (i) This study was given Ethical Approval by the Institutional Review Board prior to the conduct of this study. (ii) Informed consent was obtained from all participants. (iii) The authors received no funding for the preparation of this manuscript. (iv) The authors of this work have no disclosures or potential conflicts of interest related to this study. B.S.L.: Consultant and speaker’s bureau for Zim Vie Tether and receives royalties. J.M.P.: Consultant for ZimVie. A.A.: Consultant for Zimvie and receives royalties. L.C.B.: PATENTS (1) Kunes; Brian; (Washington, DC); Hollins; Stacy; (New Castle, VA); Blakemore; Laurel; (Falls Church, VA); Hsu; Brian; (Greenwich, AU); Ferguson; John; (Auckland, NZ). Anterior tether tensioner. US Patent Application 17/091773, filed November 6, 2020. (2) Blakemore, Laurel (Williston, FL) Ross, Catherine(Arlington, VA). Tethering Screw System. US Patent 10,548,639. Filed April 25, 2016, issued February 4, 2020. P.O.N.: ZimVie through Setting Scoliosis Straight Foundation—Research support. A.F.S.: Zim Vie—IP royalties and paid consultant. L.L.H.: Zimmer: Paid presenter or speaker. S.A.S.: Globus Medical Royalties. The remaining authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective review of a prospectively collected multicenter database., Objective: To compare outcomes of patients with cerebral palsy (CP) who undergo surgery for scoliosis with normal lordosis (NL) versus hyperlordosis., Summary of Background Data: Surgical correction of scoliosis with lumbar hyperlordosis is challenging. Hyperlordosis may confer higher perioperative morbidity, but this is not well understood., Materials and Methods: A multicenter database was queried for CP patients who underwent surgery from 2008 to 2017. The minimum follow-up was 2 years. Two groups were identified: lumbar lordosis <75° (NL) versus ≥ 75° hyperlordosis (HL). Perioperative, radiographic, and clinical outcomes were compared., Results: Two hundred seventy-five patients were studied: 236 NL and 39 HL (-75 to -125°). The mean age was 14.1 years, and 52.4% were male. Patients with hyperlordosis had less cognitive impairment (76.9% vs. 94.0%, P =0.008) and higher CPCHILD scores (59.4 vs. 51.0, P =0.003). Other demographics were similar between the groups. Patients with hyperlordosis had greater lumbar lordosis (-90.5 vs. -31.5°, P <0.001) and smaller sagittal vertical axis (-4.0 vs. 2.6 cm, P <0.001). Patients with hyperlordosis had greater estimated blood loss (2222.0 vs. 1460.7 mL, P <0.001) but a similar perioperative complication rate (20.5% vs. 22.5%, P =0.787). Significant correction of all radiographic parameters was achieved in both groups. The HL group had postoperative lumbar lordosis of -68.2° and sagittal vertical axis of -1.0 cm. At a 2-year follow-up, patients with hyperlordosis continued to have higher CPCHILD scores and gained the greatest benefit in overall quality of life measures (20.0 vs. 6.1, P =0.008). The reoperation rate was 10.2%: implant failure (3.6%), pseudarthrosis (0.7%), and wound complications (7.3%). There were no differences in the reoperation rate between the groups., Conclusion: Surgical correction of scoliosis with hyperlordosis is associated with greater estimated blood loss but similar radiographic results, perioperative morbidity, and reoperation rate as normal lordosis. Patients with hyperlordosis gained greater overall health benefits. Correction of ≥25% of hyperlordosis seems satisfactory., Level of Evidence: 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Anterior vertebral body tethering (AVBT) is an alternative to posterior spinal fusion (PSF) for the surgical treatment of scoliosis. The present study utilized a large, multicenter database and propensity matching to compare outcomes of AVBT to PSF in patients with idiopathic scoliosis., Methods: Patients with thoracic idiopathic scoliosis who underwent AVBT with a minimum 2-year follow-up retrospectively underwent 2 methods of propensity-guided matching to PSF patients from an idiopathic scoliosis registry. Radiographic, clinical, and Scoliosis Research Society 22-Item Questionnaire (SRS-22) data were compared preoperatively and at the ≥2-year follow-up., Results: A total of 237 AVBT patients were matched with 237 PSF patients. In the AVBT group, the mean age was 12.1 ± 1.6 years, the mean follow-up was 2.2 ± 0.5 years, 84% of patients were female, and 79% of patients had a Risser sign of 0 or 1, compared with 13.4 ± 1.4 years, 2.3 ± 0.5 years, 84% female, and 43% Risser 0 or 1 in the PSF group. The AVBT group was younger (p < 0.001), had a smaller mean thoracic curve preoperatively (48 ± 9°; range, 30° to 74°; compared with 53 ± 8°; range, 40° to 78° in the PSF group; p < 0.001), and had less initial correction (41% ± 16% correction to 28° ± 9° compared with 70% ± 11% correction to 16° ± 6° in the PSF group; p < 0.001). Thoracic deformity at the time of the latest follow-up was 27° ± 12° (range, 1° to 61°) for AVBT compared with 20° ± 7° (range, 3° to 42°) for PSF (p < 0.001). A total of 76% of AVBT patients had a thoracic curve of <35° at the latest follow-up compared with 97.4% of PSF patients (p < 0.001). A residual curve of >50° was present in 7 AVBT patients (3%), 3 of whom underwent subsequent PSF, and in 0 PSF patients (0%). Forty-six subsequent procedures were performed in 38 AVBT patients (16%), including 17 conversions to PSF and 16 revisions for excessive correction, compared with 4 revision procedures in 3 PSF patients (1.3%; p < 0.01). AVBT patients had lower median preoperative SRS-22 mental-health component scores (p < 0.01) and less improvement in the pain and self-image scores between preoperatively and the ≥2-year follow-up (p < 0.05). In the more strictly matched analysis (n = 108 each), 10% of patients in the AVBT group and 2% of patients in the PSF group required a subsequent surgical procedure., Conclusions: At a mean follow-up of 2.2 years, 76% of thoracic idiopathic scoliosis patients who underwent AVBT had a residual curve of <35° compared with 97.4% of patients who underwent PSF. A total of 16% of cases in the AVBT group required a subsequent surgical procedure compared with 1.3% in the PSF group. An additional 4 cases (1.3%) in the AVBT group had a residual curve of >50° that may require revision or conversion to PSF., 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/H274)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

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: This study aimed to determine (1) does vertebral body tethering (VBT) produce differential growth modulation in individual vertebrae in patients with idiopathic scoliosis, (2) does VBT change disc shape, and (3) does VBT affect total spine length?, Methods: Patients with idiopathic scoliosis treated with VBT of the main thoracic curve and minimum 2-year follow-up were included. Vertebrae and discs were categorized as uninstrumented proximal thoracic, instrumented main thoracic, or uninstrumented thoracolumbar-lumbar. The left- and right-sided heights of each vertebra and disc were measured on subsequent radiographs to assess for differential growth. T1-T12 thoracic and T1-S1 thoracolumbar growth velocities were compared with standardized reference data., Results: Fifty-one patients (764 vertebrae and 807 discs) were analyzed. The average major curve magnitude improved from 46° ± 11° to 17° ± 11° at 2-year follow-up. Differential growth was observed in MT vertebrae, in which the left/concave side grew 2.0 ± 2.2 mm compared with 1.5 ± 2.3 mm on the right/convex (tethered) side (p < 0.001). Differential height changes were observed for all discs, but were most pronounced in instrumented MT discs, in which the right/convex sides decreased by an average of 1.2 mm each, compared with no significant height change on the left/concave side. Total spinal growth velocities were not significantly different from standard reference data., Conclusion: Vertebral body tethering limits convex spinal growth as designed while permitting concave growth. Curve correction results from differential vertebral growth and decreased convex disc height. Overall spinal growth continues at the expected rate., Level of Evidence: Level IV case series., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: Multicenter retrospective review., Objective: To calculate overall incidence of pedicle screw "plowing" in adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF). To identify risk factors for pedicle screw plowing and associated postoperative outcomes, including loss of correction and revision rate., Summary of Background Data: Curve correction of AIS generates perpendicular stresses that can cause pedicle screws to lose alignment and "plow" through pedicles craniocaudally., Methods: We reviewed records of 1057 patients who underwent PSF for AIS from 2002 to 2015. Preoperative and first postoperative erect radiographs were evaluated by two observers to determine (1) presence of plowing and (2) subsequent loss of correction (LOC). Plowing was defined as more than 25° sagittal angulation compared with pedicle axis or entry of the most dorsal part of the screw outside the pedicle projection. LOC was defined as postoperative change in focal angulation of an instrumented spinal level, when in consensus of both reviewers. Bivariate analyses were performed (alpha = 0.05)., Results: Nineteen thousand five hundred sixty nine screws were assessed across our cohort of 1057 patients. Both observers agreed that 48 patients (4.5%) demonstrated plowing of more than or equal to one pedicle screw. For 72 screws (0.4%), both observers noted plowing, most commonly through the cranial cortex of the pedicle (65/72 screws) and at the lowest instrument vertebra (LIV) (17/72 screws). Factors associated with plowing included larger curves (P = 0.02); lower mean pedicle screw density (P = 0.0003); skeletal immaturity as measured by open triradiate cartilage (P = 0.04); and younger chronological age at time of surgery (P = 0.04). LOC occurred in 13 patients, most commonly at LIV (P < 0.0001). Revision rate for loss of screw fixation was higher in the plowing group (P = 0.003)., Conclusion: Pedicle screw plowing occurred in 4.5% of AIS patients, especially in those skeletally immature and with decreased implant density. Plowing commonly occurred in the cranial direction and was associated with LOC, particularly at the LIV.Level of Evidence: 3., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To identify the prevalence and predictors of nonspecific back pain in primary thoracic adolescent idiopathic scoliosis (AIS) patients at 10 years after surgery., Methods: This was a case-control multi-center study. A query of patients who underwent surgical correction of major thoracic AIS between 1997 and 2007 with 10-year follow-up was reviewed. SRS-22 pain scores at 10 years were classified as below normal (≤ 2 standard deviations below average for controls of similar age/sex from published literature) or within/above the control range., Results: One hundred and seventy-one patients with an average of 10.5 ± 0.8-years follow-up were included. Average age at surgery was 14 ± 2 years. The rate of pain was 23% for males and 11% for females (p = 0.08). Differences in age, 10-year SRS mental health score, and radiographic measures were noted. Of 12 patients who underwent revision surgery, 42% reported below normal pain scores versus 11% in cases without revision (p = 0.012). Classification and regression tree (CART) analysis identified 10-year thoracic curve magnitude and 10-year mental health scores as significant predictors. Thoracic Cobb of ≤ 26° at 10 years was associated with a 7% rate of below normal pain scores compared to 27.5% when the curve was > 26° (OR = 4.8, p < 0.05). Of those with a curve ≤ 26°, no patients had abnormal pain if the SRS mental health score was > 4.2 and 15% had more pain than normal if mental health score was ≤ 4.2 (OR 23, p < 0.05)., Conclusion: Increased primary thoracic curve magnitude (> 26°) at 10 years was the primary predictor of increased pain. For patients with less coronal deformity (< 26°), a poor mental health score was associated with an increased rate of pain. Male gender and revision surgery may also play a role in increased pain, however, the overall frequency of these variables were low., Level of Evidence: Level 3., (© 2021. Scoliosis Research Society.)

Study Design: Retrospective, comparative, multicenter., Introduction: Growth modulating spinal implants are used in the management of scoliosis such as anterior vertebral body tethering. A motion-sparing posterior device (PDDC) was recently approved for the treatment of moderate AIS. The purpose of this study was to determine if the PDDC can modulate growth in skeletally immature patients with AIS., Methods: From a database of patients treated with the PDDC over 4 years, we identified those who had a minimum of 2 years follow-up. Pre-operative and post-operative Cobb angles and coronal plane wedging of the apical vertebra were evaluated on standing full length radiographs. Independent sample t test and one-way ANOVA with post-hoc Tukey HSD analysis was used to compare three groups in varying skeletal maturity: Risser 0-1, Risser 2-3, and Risser 4-5., Results: 45 patients (14.2-years old, 11-17) were evaluated with a mean pre-op curve of 46° (35°-66°). The average preoperative major curve magnitude, of either Lenke 1 or 5 curve type, was similar among the three groups 47.6°, 46° and 41.5°. Deformity correction was similar in the three groups, with reduction to 26.4°, 20.4° and 26.2°, respectively, at final follow-up [p < 0.05]. Pre-op wedging 7.4° (3.8°-15°) was reduced after surgery to 5.7° (1°-15°) (p < 0.05). Of those patients, Risser 0-1 (n = 16) had preoperative wedging of 9.5° (6°-14.5°) that was reduced to 5.4° (1°-8°) postoperatively (p < 0.05); Risser 2-3 (n = 15) had pre-op 7.7° (4°-15°) vs. post-op 7.0° (3°-15°); Risser 4-5 (n = 14) had pre-op 4.8° (3.8°-6.5°) vs. post-op 4.7° (3.7°-6.5°). Delta Wedging in Risser 0-1 stage was significantly different than for Risser 2-3 and for Risser 4-5., Conclusion: The posterior dynamic deformity correction device was able to modulate vertebral body wedging in skeletally immature patients with AIS. This was most evident in patients who were Risser 0-1. In contrast, curve correction was similar among the three groups. This finding lends support to the device's ability to modulate growth.

Study Design: Prospective cohort review., Objective: To compare two AIS databases to determine if a performance improvement-based surgeon group has different outcomes compared to a national database. The American College of Surgeon's National Quality Improvement Program (ACS-NSQIP) and a surgeon study group (SG) collect prospective data on AIS surgery outcomes. NSQIP offers open enrollment to all institutions, and SG membership is limited to 15 high-volume institutions, with a major initiative to improve surgeon performance. While both provide important outcome benchmarks, they may reflect outcomes that are not relatable nationwide., Methods: The ASC-NSQIP Pediatric Spine Fusion and SG database were queried for AIS 30- and 90-day complication data for 2014 and 2015. Prospective enrollment and a dedicated site coordinator with rigorous data quality assurance protocols existed for both registries. Outcomes were compared between groups with respect to superficial and deep surgical site infections (SSI), neurologic injury, readmission, and reoperation., Results: There were a total of 2927 AIS patients included in the ASC-NSQIP data and 721 in the SG database. Total complication rate was 9.4% NSQIP and 3.6% SG. At 90 days, there were fewer surgical site infections reported by SG than ASC-NSQIP (0.6% vs. 1.6%, p = 0.03). Similarly, there were less spinal cord injuries (0.8% vs 1.5%, p = 0.006), 30-day readmissions (0.8% vs. 2.6%, p = 0.002), and 30-day reoperations (0.6% vs. 1.7%, p = 0.02) in the SG cohort., Conclusions: Comparison of these two data sets suggests a range of complications and readmission rates, with the SG demonstrating lower values. These results are likely multi-factorial with the performance improvement initiative of the SG playing a role. Understanding the rate and ultimate risk factors for readmission and complications from big data sources has the potential to further drive quality improvement., Level of Evidence: III.

Hypothesis: Body surface topography (ST) improvements are associated with surgical correction in adolescent idiopathic scoliosis (AIS) and correlate with radiographic imaging., Design: Prospective observational study., Introduction: Patients undergoing correction of AIS are most affected by body image. Radiographs have been the standard assessment tool but do not assess body shape features. ST, a validated, radiation-free assessment tool, directly represents the patient's deformity. We set out to assess ST improvements associated with surgical correction in AIS., Methods: Twenty-three consecutive operative AIS patients were enrolled and had radiographs and posterior ST obtained pre- and postoperatively (PO). ST changes were compared using paired t test, and correlations of ST with radiograph measurements were evaluated by linear regression., Results: Mean age at surgery was 15.0 ± 2 years, 82.6% female with mean follow-up of 1.0 year. Major Cobb angle improved from 56.91° ± 15.57° to 13.70° ± 4.89°. ST scoliosis angle corrected from 41.43° ± 11.52° to 11.78° ± 7.84° (p < .0001). Trunk length increased from 401.22 ± 32.43 to 422.30 ± 25.77 mm (Δ21.08 mm; p = .0004). Pelvic obliquity (waist asymmetry) trended toward improvement (6.0 ± 4.3 vs. 5.3 ± 7.1 mm; p = .06). Surface rotation was corrected from 17.35 ± 6.73 to 11.8 ± 4.12 mm (p < .0001), highly correlated with clinical trunk rotation (T p = .002 and TL p = .02). ST highly correlated with radiographic parameters. Sagittal balance correlated with improved function (p = .02)., Conclusion: ST, a radiation-free body shape assessment tool, improved with surgical correction of AIS and was highly correlated with radiographic outcomes.

Background: Traditionally, adolescent idiopathic scoliosis (AIS) has not been associated with back pain, but the increasing literature has linked varying factors between pain and AIS and suggested that it is likely underreported., Purpose: Our objective was to investigate factors associated with post-op pain in AIS., Methods: A prospectively collected multicenter registry was retrospectively queried. Pediatric patients with AIS having undergone a fusion with at least 2 years of follow-up were divided into two groups: (1) patients with a postoperative SRS pain score ≤ 3 or patients having a reported complication specifically of pain, and (2) patients with no pain. Patients with other complications associated with pain were excluded., Results: Of 1744 patients, 215 (12%) experienced back pain after postoperative recovery. A total of 1529 patients (88%) had no complaints of pain, and 171 patients (10%) had pain as a complication, with 44 (2%) having an SRS pain score ≤ 3. The mean time from date of surgery to the first complaint of back pain was 25.6 ± 21.6 months. In multivariate analysis, curve type (16% of Lenke 1 and 2 curves vs. 10% of Lenke 5 and 6, p = 0.002) and a low preoperative SRS pain score (no pain 4.15 ± 0.67 vs. pain 3.75 ± 0.79, p < 0.001) were significant. When comparing T2-4 as the upper instrumented vertebrae in a subgroup of Lenke 1 and 2 curves, 9% of patients had pain when fused to T2, 13% when fused to T3, and 18% when fused to T4 (p = 0.002)., Conclusion: 12% of all AIS patients who underwent fusion had back pain after postoperative recovery. The most consistent predictive factor of increased postoperative pain across all curve types was a low preoperative SRS pain score. These slides can be retrieved under Electronic Supplementary Material.

Study Design: A retrospective analysis of a prospectively collected database was performed., Objective: The purpose of this study is to compare 3-dimensional correction associated with the anterior release (AR) and contemporary posterior instrumentation versus posterior-only surgery., Summary of Background Data: The role of AR as a tool in the treatment of adolescent idiopathic scoliosis (AIS) has seen a decline with the popularization of thoracic pedicle screw instrumentation., Methods: Five surgeons were queried for all surgical thoracic AIS cases from 2003 to 2010 treated with thoracoscopic AR/fusion and contemporary posterior instrumentation and fusion and thoracic pedicle screw instrumentation (>80% screws) with 2-year follow-up. These cases were then matched with posterior spinal fusion only cases from a multicenter prospective database. The 2 groups were matched on the basis of major curve magnitude within 5 degrees, T5-T12 kyphosis within 9 degrees, and angle of trunk rotation within 9 degrees. Radiographic and clinical parameters were compared for the 2 groups. Continuous variables were analyzed with analysis of variance and categorical dependent variables with the χ test., Results: A total of 47 cases of AR were matched to 47 (1:1 match) posterior spinal fusion cases. Preoperative parameters were similar between groups (P>0.05). Postoperatively, AR cases had a lower major curve (20 vs. 25 degrees, P=0.034; 72% vs. 66% correction, P=0.037). T5-T12 kyphosis was greater in the AR cases (26 vs. 20 degrees; P=0.005). The angle of trunk rotation was similar for the groups. Anchor density was lower in the AR group (1.6 vs. 1.9; P<0.0001). There were 3 complications associated with the AR: 1 pneumothorax and 2 conversions to minithoracotomies for failure to maintain single lung ventilation., Conclusions: AR improves coronal and sagittal plane correction in contemporary AIS surgery with a satisfactory complication profile with less pedicle screw density required for clinically similar corrections. A further prospective study on the benefits of AR may help define specific indications.

Purpose: Determining whether to fuse a Lenke 5 curve to L3 or to L4 is often a difficult decision. The purpose of this study was to determine preoperative variables predictive of an "ideal" or "less than ideal" outcome for Lenke 5 curves instrumented to L3., Methods: A multicentre registry of adolescent idiopathic scoliosis patients was queried for surgically treated Lenke 5 curves with a lowest instrumented vertebra (LIV) of L3 and minimum 2 years of follow-up. Five seasoned surgeons qualitatively rated the 2-year postoperative images as "ideal" or "less than ideal" with respect to correction and alignment. Preoperative and postoperative radiographic variables were compared between the two groups. Multivariate regression analysis was performed to determine variables most predictive of a "less than ideal" outcome., Results: One hundred and thirty-nine patients met criteria. Twenty-three were considered "less than ideal" by ≥ 3 surgeons; 81 were unanimously "ideal". Preoperatively, the "less than ideal" group had significantly stiffer curves, greater apical translation, and greater LIV angulation and translation. Multivariate regression found that preoperative L3 translation (p = 0.009) was the single most important predictor of a "less than ideal" outcome: < 3.5 cm consistently resulted in an "ideal" outcome, while > 3.5 cm risked a "less than ideal" result., Conclusion: While multiple variables are important in achieving an "ideal" outcome in Lenke 5 curves, this study found preoperative L3 translation was the most important predictor of success with an L3 translation < 3.5 cm being a potential threshold for selecting L3 as the LIV. These slides can be retrieved under Electronic Supplementary Material.

Background: Intraoperative blood loss during posterior spinal fusion for adolescent idiopathic scoliosis (AIS) has been reportedly associated with multiple factors. This study aims to investigate the effect of thoracic kyphosis on blood loss in AIS spinal fusion., Methods: Patients with AIS who underwent posterior-only procedures for Lenke I and II type curves were identified. All included patients had intraoperative tranexamic acid. Difference in estimated blood loss per blood volume (EBL/BV) was identified between hypokyphotic curves (-), normal curves (N), and hyperkyphotic curves (+) classified based on Lenke sagittal modifier. Regression analysis was then performed with EBL/BV as dependent variable. Independent variables included radiographically measured T5-T12 kyphosis and calculated 3D T5-T12 kyphosis in addition to sex, body mass index (BMI), operative time, number of fused vertebrae, number of Ponte osteotomy levels, and main thoracic coronal curve., Results: In total, 837 patients were included. For female patients: EBL/BV was significantly higher for (-) (18%) compared with (N) (16%) and (+) (14%). A total of 29 female patients had T5-T12≤0 (-15 to 0 degree). EBL/BV was not significantly higher than patients with T5-T12>0 degree (18%±9% vs. 16%±11%; P=0.212). For male patients: EBL/BV was significantly higher in (-) (23%) compared with (+) (16%). In total, 14 male patients had T5-T12≤0 (-13 to 0) degree. EBL/BV was significantly higher than patients with T5-T12>0 degree (32%±18% vs. 18%±13%; P=0.015). Significant factors in predicting EBL/BV were sex, BMI, number of fused levels, and both 2D and 3D T5-T12 kyphosis. Male sex as well as every fused-level predicted an increase in EBL/BV~2%. Every 10-unit decrease in BMI predicted an increase in EBL/BV of 7%. Every 10-degree decrease in 2D or 3D T5-T12 kyphosis predicted an increase in EBL/BV~1%. The impact of the number of Ponte osteotomy levels was not significant., Conclusions: This study supports the role of sagittal thoracic alignment in affecting EBL/BV in AIS surgery. Male patients with severe thoracic lordosis (T5-T12≤0 degree) are the highest risk group for intraoperative bleeding. These findings are helpful in predicting the intraoperative blood loss for patients with AIS undergoing posterior spinal fusion. In addition to sex and number of fused levels, decreased thoracic kyphosis is associated with increased blood loss., Level of Evidence: Level III-prognostic study.

Study Design: Retrospective review of prospectively collected data., Objective: To determine whether adolescent idiopathic scoliosis (AIS) patients with active complications at two-year follow-up demonstrate lower Scoliosis Research Society (SRS-22) questionnaire scores., Summary of Background Data: There is limited evidence as to whether the SRS-22 is sensitive to complications in postoperative AIS patients., Methods: Surgical patients with SRS-22 scores completed at two-year follow-up were included. Five groups were created: no complication, minor complication resolved by 2 years, major complication resolved by 2 years, minor complication active, and major complication active at 2 years. Likelihood of reaching a minimal clinically important difference (MCID) for pain (0.20) and self-image (0.98) was evaluated., Results: 1,481 patients were identified. Major complications active at two years existed in 2.2% of patients. These patients had the lowest score in all domains and total scores (p < .05). If a minor complication was active, scores were impacted for pain, self-image, satisfaction, and total (p < .05). No differences were found between no complication and resolved complications. Patients with active major complications were more likely to have a pain score that worsened from pre- to two years reaching MCID (52%) compared to the other four groups (range 18%-29%, odds ratio [OR] 3.6, p < .001). They also had a nonsignificant decreased rate of improvement of self-image score at an MCID level (42% vs. range 51%-66%, OR 0.56, p = .10)., Conclusions: When timing is considered, the SRS-22 demonstrates the ability to discriminate between patients with and without a complication. Active experience of a major complication impacted SRS-22 scores, in particular, the rate of worsening scores for pain, self-image, function, and total score., Level of Evidence: Level III., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Informed decision making for operative treatment of the skeletally mature adolescent idiopathic scoliosis (AIS) patient meeting surgical indications requires a discussion of differences in operative morbidity in adult scoliosis versus AIS. This study evaluated differences in operative data and outcomes between AIS and adult scoliosis patients based on an estimated natural history of curve progression., Methods: Twenty-eight adult scoliosis patients (43.7 ± 15.8 years; 93% F) were 1:2 matched with 56 (Risser 4/5) AIS patients (15.7 ± 2.1 years) based on gender and curve type as vetted by 5 surgeons' consensus in committee. Curve progression of 0.3°/year for the first 10 years following skeletal maturity and a 0.5°/year thereafter was assumed to estimate curve progression from AIS to adulthood for the adult counterpart. Operative data, complications, and quality of life (Scoliosis Research Society [SRS-22r] questionnaire) measures were evaluated, with a minimum 2-year follow-up., Results: Postoperative major Cobb and percentage correction were similar between adult versus AIS, whereas operative time, percentage estimated blood loss (EBL; % total blood volume), length of hospital stay (LOS), and total spine levels fused were greater for adult patients (p < .05). No difference was found in EBL, operative time, or LOS when normalized by levels fused. Ten (36%) adult scoliosis patients were fused to the pelvis compared with none in AIS (p < .0001). Major complication rate was higher for adult versus AIS (25% vs. 5.4%; p < .05). Preoperative SRS-22r scores were worse for adult patients; however, they demonstrated greater improvement in SRS-22r than the AIS cohort at final follow-up. A higher percentage of adult patients reached the MCID in self-image domain than the AIS patients (92.3% vs. 61.8%; p = .0040)., Conclusion: Treatment of the adult scoliosis patient who has undergone an estimated natural history of progression is characterized by greater levels fused, operative time, and higher complication rates than the AIS counterpart. Longer-term follow-up of AIS is needed to define the benefits of early intervention of relatively asymptomatic adolescent patients versus late treatment of symptomatic disease in the adult., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Biomechanical numerical simulation analysis of implant design and density in adolescent idiopathic scoliosis posterior instrumentation., Objectives: To evaluate the combined effect of pedicle screw design and density on deformity correction and construct load-sharing capacity., Summary of Background Data: Screw density is an area of popular study because of the impact of cost and potential patient morbidity of higher-density constructs. Using fewer screws raises concern about reduced correction and greater forces on each screw., Methods: Personalized spinal numerical models were created for five patients. The correction techniques from five spine surgeons using both a high- and a low-density implant pattern (2 vs. 1.4 ± 0.22 screws/level) with uniaxial, multiaxial, and favored angle screws were simulated. The predicted correction and forces sustained by the implants were compared. The postoperative load-sharing capacity of a high- and a low-density construct, with or without crosslinks, was compared by simulating daily activities motions., Results: The major coronal curve correction was similar with high- and low-density constructs (73% ± 10% vs. 72% ± 10%; p > .05) but was higher when using uniaxial (77% ± 8%) compared to multiaxial (69% ± 11%) and favored angle screws (71% ± 10%; p = .009). High- and low-density constructs sustained similar intraoperative peak forces (305 ± 61 N vs. 301 ± 73 N; p = .23) regardless of screw design (all p > .05). Multiaxial and favored angle screws reduced the peak axial force by 23% and 38% compared to uniaxial screws (p = .007). The high-density construct reduced the postoperative loads sustained by each implant by 31% (p = .006). Crosslinks had no effect on load sharing (p = .23)., Conclusion: High- and low-density implant patterns achieved similar coronal correction with equivalent capacity to share corrective forces regardless of the screw design. Increased degrees of freedom of the screw head reduces the capacity to correct coronal deformity but generates lower bone-screw forces. The reduced number of screws increased the postoperative forces sustained by each screw, but its effect on potential complications requires further investigations., Level of Evidence: Level 4., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Multicenter review of prospectively collected data., Objective: The purpose of this study was to evaluate whether a UIV of T2 reliably results in level shoulders postoperatively., Summary of Background Data: Adolescent idiopathic scoliosis (AIS) patients with a risk of a high left shoulder postoperatively are generally recommended to have instrumentation to T2, those with neutral shoulders a T3 UIV, and those with an elevated right shoulder are recommended a UIV of T4 or below in order to achieve postoperative shoulder balance., Methods: A prospective, multicenter AIS database was queried for subjects with minimum two-year follow-up who underwent posterior spinal fusion to correct their main thoracic deformity. Subjects were grouped based on their proximal fusion level. A high shoulder was defined as >1 cm difference on radiographs., Results: A total of 626 subjects met inclusion criteria and were divided by UIVs of T2 189, T3 205, and T4 232. Preoperatively, the groups had similar rates of balanced shoulders (T2 47%, T3 49%, T4 45%) and high left shoulders (T2 8.5%, T3 8.8%, and T4 7.3%). Postoperatively, there was a greater percentage of postoperative shoulder imbalance for T2 (45%) and T3 (48%) UIV groups as compared to T4 (34%, p = .008). As expected, the T2 (46%) and T3 (49%) groups had significantly better upper thoracic curve correction as compared to the T4 group (42%, p < .001)., Conclusions: The selection of a T4 UIV results in more shoulder balance postoperatively than T2 or T3, regardless of which shoulder was elevated preoperatively. The selection of a T2 UIV does not guarantee postoperative shoulder balance following posterior treatment of main thoracic curves; however, when compared to the more caudal UIV of T4, an improved upper thoracic curve correction can be anticipated., Level of Evidence: Level 3., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Retrospective cohort study of spine fusion surgery utilizing the New York State Inpatient Database., Objective: The objective was to determine whether there were differences in reoperation rates among pediatric scoliosis associated with various etiologies compared with idiopathic scoliosis., Summary of Background Data: The incidence of postoperative complications and reoperations is known to vary among patients with diverse scoliosis pathologies. As these are heterogeneous conditions and often with rare occurrence, it is difficult to compare them in a single study. We aimed to assess reoperation events after fusion for several etiologies of pediatric scoliosis., Methods: The 2008 to 2011 New York State Inpatient Database was queried using International Classification of Diseases (ICD-9-CM) codes for patients with in-hospital stays including a spine arthrodesis for scoliosis. All approaches, all fusion lengths, and ages 10 to 21 were included. Patient identifiers and linkage variables were used to identify revisits. The relative risk of reoperation was calculated for several rare conditions associated with scoliosis., Results: Two thousand three hundred fifty-six pediatric scoliosis fusion surgeries were identified in 2008 in the state of New York. The 1- and 4-year reoperation rate for idiopathic scoliosis was 0.9% and 1.6%, respectively. For nonidiopathic scoliosis, the 1- and 4-year rates were 4.2% and 20.4%, respectively. Of the nonidiopathic scoliosis subtypes, congenital scoliosis (4.7% risk at 1 y, 41.6% at 4 y), the neuromuscular disease arthrogryposis (7.3% risk at 1 y, 28.6% at 4 y), and syndrome neurofibromatosis (9.1% at 1 y, 32.3% at 4 y) showed the highest risk for reoperation. Length of stay and hospital charges were higher for reoperations., Conclusions: Using a large administrative database, we identified neuromuscular, syndromic, and congenital forms of scoliosis that have the highest relative risk for a reoperation within 1 year. At-risk populations should be identified and resources allocated and preventative measures instituted accordingly to prevent these costly events., Level of Evidence: Level III.

Study Design: A retrospective review was conducted of 57 consecutive patients (26 female; mean age: 16.6 years) who underwent posterior or combined anterior-posterior spinal fusion for neuromuscular scoliosis (NMS) from 2006 and 2007., Objectives: We aimed to assess which patient and surgical factors are predictive of increased blood loss and transfusion requirements during spinal fusion for NMS., Background: Spinal fusion surgery in patients with NMS has been associated with significant intraoperative blood loss and transfusion requirements. Specific factors predictive of greater blood loss have not been delineated; recognizing these factors will assist predicting the need for blood products and antifibrinolytics., Methods: Data gathered included demographic, operative (operative time, levels fused, estimated blood loss, cell saver transfused, IV fluids transfused, and units transfused), and laboratory parameters (hemoglobin, hematocrit, platelet count, prothrombin time, partial prothrombin time, and international normalized ratio). Multivariate linear regression was used to identify parameters associated with greater intraoperative blood loss and transfusion requirements., Results: Eighty-three percent of patients underwent primary surgery with mean levels fused of 13.5. Regression analysis showed a statistically significant increase in blood loss with age (p = 0.00), operative time (p = 0.00), and postoperative platelets (p = 0.016). Each year of increasing age corresponded with an increase of 50 cc of estimated blood loss (EBL). Each additional hour of operative time was associated with an additional EBL of 147.7 cc. Each additional unit of postoperative platelets was associated with an EBL decrease of 2.8 cc. Units transfused increased with age (p = 0.00): each year of increasing age corresponded with an increase of 0.04 units of blood transfused., Conclusions: Patients with NMS remain a challenging group of patients to treat. We find that age, operative time, and postoperative platelets are predictive of increased blood loss while only age was related to greater transfused units. Our findings may predict the need for blood products and antifibrinolytic agents preoperatively in this heterogeneous population, especially as patients age.

Study Design: Retrospective analysis of a prospectively collected, national inpatient hospital database., Objective: We aimed to investigate comorbid psychiatric disorders in the adult spinal deformity (ASD) population. We hypothesized that a high incidence of comorbid psychiatric disorders in ASD would negatively impact perioperative outcomes., Summary of Background Data: Patients with adult spinal fusion (ASF) suffer from severe back pain and often depression. Psychiatric comorbidities in the ASD population are not well understood, despite the apparent psychological effects of spinal deformity-related self-image., Methods: The Nationwide Inpatient Sample databases from 2001 to 2009 were queried for patients ages 18 years or older with in-hospital stays including a spine arthrodesis. Patients were divided into two groups: ASD (diagnosis of scoliosis, excluding neuromuscular and congenital) and all other ASF. Subjects were further stratified by presence of a comorbid psychiatric diagnosis. Differences between each surgical group in psychiatric frequency and complications were calculated using analysis of variance, adjusted for operative complexity. A binary logistic regression analyzed the association between psychiatric diagnoses and likelihood of complications., Results: A total of 3,366,352 ASF and 219,975 ASD patients were identified. The rate of comorbid psychiatric diagnoses in ASD was significantly higher (23.5%) compared to ASF patients (19.4%, P < 0.001). Complication rates were higher for ASD compared to ASF; patients without a psychiatric diagnosis had lower (or comparable) complication rates than psychiatric patients, across all disorder categories. Patients with psychotic disorders and dementia showed more complications than controls; patients with mood, anxiety and alcohol disorders showed fewer., Conclusion: Psychiatric comorbidities are more common in the ASD population than in adult fusion patients. ASD and ASF patients with the most common psychiatric disorders (mood, anxiety, and alcohol abuse) are not at increased risk for complications compared to controls. Those patients with psychotic disorders and dementia are at a significant risk for increased complications and surgeons should be aware of these specific risks., Level of Evidence: 2.

Introduction: Sagittal alignment abnormalities in Scheuermann kyphosis (SK) strongly correlate with quality of life measures. The changes in spinopelvic parameters after posterior spinal fusion have not been adequately studied. This study is to evaluate the reciprocal changes in spinopelvic parameters following surgical correction for SK., Methods: Ninety-six operative SK patients (65% male; age 16 years) with minimum 2-year follow-up were identified in the prospective multicenter study. Changes in spinopelvic parameters and the incidence of proximal (PJK) and distal (DJK) junctional kyphosis were assessed as were changes in Scoliosis Research Society-22 (SRS-22) questionnaire scores., Results: Maximum kyphosis improved from 74.4° to 46.1° (p < .0001), and lumbar lordosis was reduced by 10° (-63.3° to -53.3°; p < .0001) at 2-year postoperation. Pelvic tilt, sacral slope, and sagittal vertical axis remained unchanged. PJK and DJK incidence were 24.2% and 0%, respectively. In patients with PI <45°, patients who developed PJK had greater postoperative T2-T12 (54.8° vs. 44.2°, p = .0019), and postoperative maximum kyphosis (56.4° vs. 44.6°, p = .0005) than those without PJK. In patients with PI ≥45°, patients with PJK had less postoperative T5-T12 than those without (23.6° vs. 32.9°, p = .019). Thoracic and lumbar apices migrated closer to the gravity line after surgery (-10.06 to -4.87 mm, p < .0001, and 2.28 to 2.10 mm, p = .001, respectively). Apex location was normalized to between T5-T8 in 68.5% of patients with a preoperative apex caudal to T8, whereas 90% of patients with a preoperative apex between T5 and T8 remained unchanged. Changes in thoracic apex location and lumbar apex translation were associated with improvements in the SRS function domain., Conclusion: PJK occurred in 1 in 4 patients, a lower incidence than previously reported perhaps because of improved techniques and planning. Both thoracic and lumbar apices migrated closer to the gravity line, and preoperative apices caudal to T8 normalized in more than two-thirds of patients, resulting in improved postoperative function. Individualizing kyphosis correction to prevent kyphosis and PI mismatch may be protective against PJK., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Purpose: Previous research has shown that with certain idiopathic scoliosis curve types, performing a selective thoracic fusion (STF) is associated with an increased risk of coronal decompensation post-operatively. The purpose of the current study was to determine the influence of curve correction and fusion level on post-operative balance in STF for adolescent idiopathic scoliosis patients with pre-operative coronal decompensation., Methods: A multicenter database was queried for subjects with right Lenke 1-4C curves, pre-operative left coronal imbalance, and 2-year follow-up who underwent STF (caudal fusion level of L1 or proximal). Rates of decompensation were compared between groups with different levels of fusion. Thoracic and lumbar curve correction as well as Scoliosis Research Society-22 outcome scores were compared between groups that were post-operatively balanced or persistently decompensated., Results: 121 patients were identified with average thoracic and lumbar curves of 53° and 41°. Mean pre- and post-operative decompensations were 2.4 ± 1.0 and 1.8 ± 1.1 cm, respectively. Eighteen patients were fused short, 62 to, and 41 were fused past the stable vertebra. Ten patients were fused short, 32 to, and 78 were fused past the neutral vertebra. Incidence of post-operative decompensation was 41%. No differences in post-operative decompensation relative to the stable or neutral vertebra were noted (p = 0.66, p = 0.74). Post-operatively, those patients who were balanced had similar thoracic curve correction (58%) to those decompensated (54%, p = 0.11); however, patients balanced post-operatively had greater SLCC (45 vs 40%, p = 0.04). No differences in SRS-22 outcome scores were noted between groups (p > 0.05)., Conclusions: There was a high rate of post-operative decompensation in patients with pre-operative coronal decompensation undergoing STF. Fusion to or past the stable or neutral vertebra did not affect the risk of persistent decompensation. Attempts to improve SLCC could reduce post-operative decompensation.

Study Design: Prospective multicenter database study., Objectives: To assess the incidence of proximal junctional kyphosis (PJK) in operative adolescent idiopathic scoliosis (AIS) using contemporary surgical techniques and to identify risk factors for PJK., Summary of Background Data: The incidence of PJK has been reported as high as 46% in AIS. Factors associated with PJK have been incompletely explored., Methods: Prospectively enrolled 851 AIS patients (2000-2011, 78.5% female, average 14.4 years) were evaluated 2 years postoperatively. Radiographic and sagittal spinopelvic parameters and rod contour angle (RCA), a new measure that reflects the proximal contouring of the rod, were independently evaluated for association with PJK based on Lenke type. Multivariate logistic regression with backward elimination was performed to identify risk factors for PJK., Results: Overall PJK incidence was 7.05% and varies based on Lenke type (Lenke 1, 6.35%; Lenke 2 and 4, 4.39%; Lenke 3 and 6, 11.64%; and Lenke 5, 8.49%; p = .06). Among patients with Lenke 1 curves, risk factors for PJK were loss of kyphosis after surgery, and stopping caudal to the upper end vertebra (UEV). The risk of developing PJK increases by 7.1% with each lost degree of kyphosis compared with preoperation that occurs after the instrumentation is placed. For Lenke 2 and 4 curves, loss of kyphosis and more lordotic (negative) RCA were risk factors for PJK. For Lenke 3 and 6 curves, larger preoperative T5-T12 kyphosis was the only significant risk factor for PJK. Upper instrumented vertebra (UIV) at or cephalad to the UEV was associated with increased risk of PJK in Lenke 5 curves, which was contrary to the finding for Lenke 1 curves. No significant correlation was found between sagittal pelvic parameters and developing PJK., Conclusion: The incidence of PJK in patients after surgery for AIS is 7.05% and varies based on Lenke type. Loss of kyphosis, larger preoperative kyphosis, UIV caudal to the proximal UEV (Lenke 1), UIV at or cephalad to the UEV (Lenke 5), and decreased RCA were the major risk factors for PJK in AIS., Level of Evidence: Level II., (Copyright © 2016 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Recent healthcare reforms have raised the importance of cost and value in the management of disease. Value is a function of benefit and cost. Understanding variability in resources utilized by individual surgeons to achieve similar outcomes may provide an opportunity for cutting costs though greater standardization. The purpose of this study is to evaluate differences in use of implants and hospital resources among surgeons performing adolescent idiopathic scoliosis (AIS) surgery., Methods: A multicenter prospective AIS operative database was queried. Patients were matched for Lenke curve type and curve magnitude, resulting in 5 surgeons and 35 matched groups (N = 175). Mean patient age was 14.9 years and curve magnitude 50°. Parameters of interest were compared between surgeons via ANOVA and Bonferroni pairwise comparison., Results: There was no significant difference in percentage curve correction or levels fused between surgeons. Significant differences between surgeons were found for percentage posterior approach, operative time, length of stay (LOS), estimated blood loss (EBL), cell saver transfused, rod material, screw density, number of screws, use of antifibrinolytics, and cessation of intravenous analgesics. Despite differences in EBL and cell saver transfused, there were no differences in allogenic blood (blood bank) use., Conclusion: Significant variability in resource utilization was noted between surgeons performing AIS operations, although radiographic results were uniform. Standardization of resource utilization and cost containment opportunities include implant usage, rod material, LOS, and transition to oral analgesics, as these factors are the largest contributors to cost in AIS surgery., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background: Though previous studies have shown improved outcomes associated with higher volume surgeons and hospitals, this may not be replicated in ASDS due to case complexity variation. We hypothesized that high-volume surgeons perform more complex surgeries. Therefore, we defined an Operative Complexity Index (OCI), specifically for the National Inpatient Samples (NIS) data, which provides information on in-hospital postoperative complications, to assess rates of adult spine deformity surgery (ASDS) cases as they relate to surgeon and hospital operative volume., Methods: The 2001 to 2010 NIS was queried for patients greater than 21 years of age with in-hospital stays, including a spine arthrodesis for a diagnosis of scoliosis. Surgeon and hospital identifiers were used to allocate records into volume quartiles by number of surgeries per year. The OCI was devised considering the number of fusion levels, surgical approach, revision status, and use of osteotomy. The index was validated using blood-loss-related diagnostic and procedural codes. One-way ANOVA assessed continuous measures. Chi-square assessed categorical measures., Results: 141,357 ASDS cases met the inclusion criteria. High-volume surgeons performed a higher rate of longfusions (> 8 levels), revision surgeries, and surgeries requiring osteotomy. The OCI showed weak, but significant, correlation with blood loss values: acute blood loss anemia (r = 0.21) and treatment with blood products (r = 0.12) (p < 0.001). High OCI also was also associated with increased length of stay (r = 0.27) and total charges (r = 0.41) (p < 0.001)., Conclusions: The operative complexity index (OCI) for ASDS increases with high-volume surgeons and centers, indicating it can be useful to adjust for surgical invasiveness in the NIS database. Operative complexity must be considered when evaluating patient safety and quality indices among hospitals and surgeons.

Background: Anterior-posterior spinal fusion (APSF) is the traditional treatment for patients with idiopathic scoliosis and open triradiate cartilage (OTRC). Our goals were to assess whether posterior-only spinal fusion (PSF) with pedicle screws can halt deformity progression as effectively as APSF in patients with OTRC, and whether selection of the distal fusion level influences curve progression., Methods: We studied a prospective multicenter database to identify all children with 2-year radiographic and clinical follow-up who were 11 years or younger with Risser grade 0 and OTRC who were treated with (1) PSF (OTRC-PSF group, N=20); or (2) APSF (OTRC-APSF group, N=9). A reference group was constructed of 20 children who were 18 years or younger with Risser grade 4 or 5 and closed triradiate cartilage (CTRC) and who were treated with PSF (CTRC-PSF group) and matched in preoperative curve magnitude and type to the OTRC-PSF group. The 3 groups were compared with respect to operative time, blood loss, length of hospital stay, and radiographic and functional outcomes (significance, P<0.05)., Results: OTRC-APSF patients had significantly longer operative time (P<0.01), greater blood loss (P=0.02), and longer hospital stays (P<0.01) than OTRC-PSF patients. At 2 years, 7 (35%) OTRC-PSF patients had >10 degrees of curve progression compared with no patients in the OTRC-APSF group (P=0.042) and 1 patient in the CTRC-PSF group (P=0.018). The OTRC-PSF group had the highest number of patients fused to the stable vertebra. Of the 11 OTRC-PSF patients fused to 1 vertebra short of stable, 6 (55%) had >10 degrees of curve progression. Of the 9 OTRC-PSF patients fused to at least the stable vertebra or lower, only 1 (11%) had curve progression. There were no significant differences in Scoliosis Research Society outcome scores between OTRC-PSF patients who did and those who did not have >10 degrees of curve progression., Conclusions: PSF with pedicle screws was associated with curve progression in a significantly greater proportion of patients with OTRC compared with APSF. Not fusing to stable was also associated with curve progression in patients treated with PSF but not APSF., Level of Evidence: Level III-therapeutic.

Background: Confidence in intraoperative neurophysiologic monitoring (IONM) data can allow scoliosis surgeons to proceed with surgery even after a monitoring alert, assuming the recovery of signals. We sought to determine the outcomes of surgical treatment of adolescent idiopathic scoliosis (AIS) after a notable IONM alert., Methods: We identified 676 patients who underwent arthrodesis with use of IONM for the treatment of AIS. The patients were divided into 2 cohorts: those who experienced a lower-extremity IONM alert and those who did not. An alert was defined as a notable change in IONM data, specifically, a ≥50% drop in somatosensory evoked potentials (SSEPs) and/or in transcranial motor evoked potentials (tcMEPs)., Results: Of the 676 patients, 36 (5.3%) experienced IONM alerts. Those patients had a larger preoperative major Cobb angle (mean of 61° ± 13° compared with 55° ± 12° for the no-alert group; p < 0.01), a greater number of levels fused (mean of 12 ± 2 compared with 11 ± 2; p < 0.01), a longer operative duration (mean of 357 ± 157 minutes compared with 298 ± 117 minutes; p < 0.01), a higher estimated blood loss (1,857 ± 1,323 mL compared with 999 ± 796 mL; p < 0.01), and a greater volume of autologous blood transfused (mean of 527 ± 525 mL compared with 268 ± 327 mL; p < 0.01). Among patients who experienced an alert and had a completed operation (34 of 36 patients), mean postoperative radiographic measurements were similar to those of the no-alert group in terms of the percentage of correction of the major Cobb angle (alert, 66% ± 13%; no alert, 64% ± 19%; p = 0.53) and of rib prominence (alert, 49% ± 36%; no alert, 47% ± 46%; p = 0.83) and measurement of thoracic kyphosis (alert, 23° ± 10°; no alert, 22° ± 2°; p = 0.58). The Scoliosis Research Society (SRS)-22 outcome scores were also similar between the 2 cohorts., Conclusions: Notable IONM changes occurred in 5.3% of the patients who underwent arthrodesis for AIS. Those patients had larger preoperative deformity, a longer operative duration, a greater number of levels fused, a higher estimated blood loss, and a greater volume of autologous blood transfused. Return of IONM data guided the surgeon to safely complete the procedure in 34 of 36 patients, with correction similar to that of patients who did not experience an alert., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.)

Introduction: Bone morphogenetic protein (BMP) can increase the likelihood of solid arthrodesis in spinal surgery. This would imply fewer reoperations for pseudarthrosis, but small cohort sizes are inadequate to monitor these events. We sought to examine adolescent idiopathic (AIS) and non-idiopathic scoliosis (NIS) for reoperation events with and without the use of BMP using a large statewide database., Methods: The 2008-2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Patients age 10 and older with a diagnosis of scoliosis and an index fusion of greater than 2 spinal motion segments were included. Patient identifiers and linkage variables were used to identify revisits. The relative risk of reoperation was calculated. The use of BMP at the initial inpatient stay was used to define the two cohorts for relative risk assessment., Results: A total of 2,658 and 2,431 cases were identified of AIS and NIS, respectively. The use of BMP at the initial visit was performed at a rate of 4.5% for AIS and 21.0% for NIS fusion surgery. For posterior fusion cases longer than eight levels, the reoperation rate for pseudarthrosis was 1.0% in AIS and 18.4% in NIS (p < .001). For NIS fusions greater than eight levels, the rate of reoperation for pseudarthrosis after using BMP at the index surgery was 5% and 22% when BMP was not used, a relative risk of 4.0 (p < .001). For AIS, there was no substantial increase in risk when not using BMP for fusion greater than eight levels (p < .001)., Conclusion: We found a significant decrease in the risk of reoperation for pseudarthrosis after long fusions when using BMP in the case of NIS. In contrast, use of BMP does not benefit the AIS population., (Copyright © 2016 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Objective: There is substantial heterogeneity in the number of screws used per level fused in adolescent idiopathic scoliosis (AIS) surgery. Assuming equivalent clinical outcomes, the potential cost savings of using fewer pedicle screws were estimated using a medical decision model with sensitivity analysis., Methods: Descriptive analyses explored the annual costs for 5710 AIS inpatient stays using discharge data from the 2009 Kids' Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality), which is a national all-payer inpatient database. Patients between 10 and 17 years of age were identified using the ICD-9-CM code for idiopathic scoliosis (737.30). All inpatient stays were assumed to represent 10-level fusions with pedicle screws for AIS. High screw density was defined at 1.8 screws per level fused, and the standard screw density was defined as 1.48 screws per level fused. The surgical return for screw malposition was set at $23,762. A sensitivity analysis was performed by varying the cost per screw ($600-$1000) and the rate of surgical revisions for screw malposition (0.117%-0.483% of screws; 0.8%-4.3% of patients). The reported outcomes include estimated prevented malpositioned screws (set at 5.1%), averted revision surgeries, and annual cost savings in 2009 US dollars, assuming similar clinical outcomes (rates of complications, revision) using a standard- versus high-density pattern., Results: The total annual costs for 5710 AIS hospital stays was $278 million ($48,900 per patient). Substituting a high for a standard screw density yields 3.2 fewer screws implanted per patient, with 932 malpositioned screws prevented and 21 to 88 revision surgeries for implant malposition averted, and a potential annual cost savings of $11 million to $20 million (4%-7% reduction in the total cost of AIS hospitalizations)., Conclusions: Reducing the number of screws used in scoliosis surgery could potentially decrease national AIS hospitalization costs by up to 7%, which may improve the safety and efficiency of care. However, such a screw construct must first be proven safe and effective.

Background Context: Revision adult spinal deformity surgery (RASDS) is a particularly high-risk intervention., Purpose: The aim was to assess complication rates in RASDS by surgeon and hospital operative volume., Study Design/setting: This was a retrospective analysis of prospectively collected data., Patient Sample: Based on a Nationwide Inpatient Sample (NIS) database (2001-2010), patients aged older than 21 years (International Classification of Diseases, Ninth Revision, Clinical Modification) with spine arthrodesis for scoliosis were included. For longitudinal analysis, the 2008-2011 New York State Inpatient Database (NY SID) was queried., Outcome Measures: The outcome measures included complication rate after RASDS., Methods: Cases were identified as primary or revision surgery with or without osteotomy performed. Annual surgeon and hospital volumes were stratified into quartiles via identifier codes. Case complexity was determined using a novel operative complexity index, based on available NIS operative parameters: levels fused, approach, osteotomy, and revision status. The primary end point was morbidity during the hospital stay. New York State Inpatient Database analysis allowed for identification of rate of reoperation for infection or pseudarthrosis/implant failure. One-way analysis of variance was used to assess continuous measures, chi-square for categorical measures., Results: Of 139,150 adult spinal deformity surgery (ASDS) cases, 4,888 revision with hospital identifiers and 1,978 with surgeon identifiers were identified. Higher-volume surgeons performed more revision cases and cases requiring osteotomy. With increasing hospital volume, complication rate for RASDS decreased (9.7% vs. 12.9% at highest- vs. lowest-volume centers, p< .001). The highest-volume surgeons showed significant decreases in the rate of major complications for RASDS (8.8% vs. 10.7% for lowest-volume surgeons, p< .001). A similar trend was observed for ASDS cases requiring osteotomy. Multiple logistic regression analysis showed that the highest-volume hospitals and surgeons showed a reduced odds ratio for all complications compared with lowest-volume hospitals. For the NY SID, 528 RASDS cases indicated reoperation rates for infection and pseudarthrosis/implant failure after RASDS were increased for the lowest-volume hospitals and surgeons., Conclusions: Perioperative complication rate associated with RASDS is lower when patients are treated by high-volume surgeons at high-volume centers. As complex cases requiring osteotomy and combined approaches are more frequent at high-volume centers, an operative complexity index helps predict the likelihood of volume-dependent complication rates. Future interhospital and intersurgeon comparisons should account for these case characteristics so that similar case complexity is compared in these analyses., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Pedicle screw constructs combined with direct vertebral body derotation (DVBD) provide a powerful corrective force of the rib prominence associated with adolescent idiopathic scoliosis (AIS). We wished to evaluate the incidence and correlative factors associated with recurrence of rib prominence (RRP) developing postoperatively despite adequate initial correction., Methods: 103 patients with AIS underwent pedicle screw fixation with DVBD without thoracoplasty and had postoperative scoliometer readings at 6, 12, and 24 months. Patients with RRP, defined as a postoperative scoliometer increase ≥5°, were compared to those without recurrence., Results: The mean rib prominence measured 14.0 ± 4.3° preoperatively, with a correction of 50.3 ± 26.7 % at 6 months, 49.0 ± 39.0 % at 1 year, and 49.1 ± 26.7 % at 2 years. RRP was identified in 15.5 % of the patients with a correction of 57.5 ± 25.5 % at 6 months, 47.2 ± 42.5 % at 1 year, and 40.4 ± 21.6 % at 2 years. At 2 years, the RRP group demonstrated a significantly larger major coronal Cobb (p < 0.05) and a trend towards less curve correction (p = 0.09). Patients with open triradiates had a significantly higher rate of RRP compared to those with closed (p = 0.01). Worsening apical vertebral rotation at 2 years post-operation occurred in 43.8 % (7/16) of the patients with RRP., Conclusion: RRP after posterior fusion for AIS with all pedicle screw constructs and DVBD occurred in 15.5 % of patients in our study. Patients with open triradiate cartilage had a significantly higher rate of RRP, although most with RRP were skeletally mature. There was a trend towards loss of coronal correction and increased apical vertebral rotation at 2 years in patients with RRP. The potential for RRP after adequate initial correction should be discussed with patients., Level of Evidence: 2.

Study Design: A prospective multicenter database of operative patients with Scheuermann kyphosis (SK) with minimum 1-year follow-up was studied for major complications compared with contemporaneous operative patients with adolescent idiopathic scoliosis (AIS) from the database., Objective: To evaluate complications associated with current surgical techniques in SK and AIS., Summary of Background Data: There is a paucity of literature regarding complications associated with SK surgical treatment, but prior data suggest an elevated neurological risk., Methods: Complication rates were compared using analysis of variance and Fisher exact test analyses. Major complications were those that were life-threatening, caused spinal cord, nerve root, or ocular injury or required reoperation including surgical site infections. A binary logistic regression determined the likelihood of complications based on diagnosis, levels fused, blood loss, operative time, and length of stay., Results: Ninety-seven patients with SK (57 males; mean age, 16.5 yr; 75.3° mean kyphosis) and 800 patients with AIS (622 females; mean age, 14.9 yr; 55.6° mean curvature) met inclusion criteria. Patients with SK had significantly more major complications than those with AIS (16.3% vs. 2.3%; P < 0.001). The SK group had more infections (10.3% vs. 0.75%) and reoperations (14.4% vs. 1.4%) (P < 0.001). Operative time was longer and more levels were fused in the SK group (P < 0.001). Surgical site infection was the most common complication. There were no significant differences in length of stay or blood loss. Patients with SK were 3.9× more likely to have a major complication than those with AIS (odds ratio: 0.26, P = 0.003). The number of levels fused was an independent predictor of major complications: each additional level fused increased the odds of a complication by 36% in both groups (odds ratio: 1.36, P = 0.034)., Conclusion: Major complications are 3.9× more likely to occur in operative SK than in AIS. The number of levels fused is an independent risk factor for major complications. Patients with SK are at higher risk for infections and reoperation than those with AIS., Level of Evidence: 2.

Study Design: Retrospective analysis of prospectively collected data from the 2001 to 2010 Nationwide Inpatient Sample database., Objective: To assess complication rates in adolescent spinal deformity by surgeon operative volume for procedures with a range of complexity., Summary of Background Data: Surgeons performing higher volumes of lumbar spinal fusion have been associated with improved surgical outcomes, according to studies using the Nationwide Inpatient Sample. This relationship has not been shown in adolescent spinal deformity surgery., Methods: The Nationwide Inpatient Sample was queried for patients aged 10 to 18 years with in-hospital stays including spinal arthrodesis for scoliosis (adolescent idiopathic, neuromuscular, and congenital scoliosis). The primary end point was hospital stay morbidity: database-defined surgical, mechanical, major medical, and neurological complications. Length of stay and hospital charges were also analyzed. Annual surgeon volumes were stratified into quartiles based on number of cases (Q1: 1, Q2: 2-7, Q3: 8-19, and Q4: 20-97). To account for variation in surgical invasiveness, an operative complexity index was used. One-way analysis of variance was used to assess differences between quartiles for continuous measures and χ for categorical measures., Results: A total of 6100 spine fusion cases met inclusion criteria for adolescent scoliosis. All complications categories were less frequent for higher volume surgeons after a primary fusion for all diagnoses. This pattern held for increasing surgical invasiveness, such as fusing 9 or more levels and became more distinct for neurological complications when comparing surgeons performing combined anterior-posterior procedures. Including all adolescent scoliosis fusions, higher surgical volume was associated with decreased length of stay and hospital charges., Conclusion: Perioperative complications after adolescent scoliosis fusion surgery are more frequent in lower volume settings. This may reflect a learning curve required for more complex cases as the trends are magnified in neuromuscular/congenital scoliosis cases or simply that higher volume surgeons are more adept at these fusions. The impact of volume on reduced length of stay and hospital charges has implications for future health care economics measures., Level of Evidence: 2.

Study Design: A retrospective analysis of a prospectively collected multicenter database., Objective: To identify the radiographical and clinical outcomes in Lenke 3 curves fused selectively (S) versus nonselectively (NS)., Summary of Background Data: Surgical treatment options for Lenke 3 curves include fusion of both curves (NS) or selective thoracic curve fusion (S). Selective fusion of the thoracic curve spares lumbar motion segments; however, it may result in marked residual deformity., Methods: A prospectively collected multicenter database was retrospectively reviewed for adolescent idiopathic scoliosis Lenke 3 curves treated with posterior spinal fusion with a minimum of 2 years of follow-up. Patients were divided into 2 groups: NS (nonselective fusion) and S (selective thoracic fusion). Radiographical and clinical data were compared between the groups using the unpaired Student t test and analysis of variance., Results: A total of 74 patients met our inclusion criteria, with 49 (66.2%) in the NS group and 25 (33.8%) in the S group. Overall, both groups were similar preoperatively except for lumbar Cobb (NS = 56.3°, S = 47.2°, P < 0.001), lumbar lordosis (NS = 56.9°, S = 67.2°, P = 0.001), lumbar rotational prominence (NS = 11.2°, S = 8.2°, P < 0.05), and lumbar apical translation (NS = 3.2 cm, S = 1.9 cm, P < 0.05). Postoperatively, NS fusion demonstrated significantly less coronal imbalance of 2 cm or less (NS = 10.2%, S = 56.0%, P < 0.001), better lumbar curve correction (NS = 68.2%, S = 51.9%, P < 0.001), better lumbar apical translation correction (NS = 1.2 cm, S = 2.1 cm, P < 0.01), and better percent correction of the lumbar prominence (NS = 66.5%, S = 40.4%, P < 0.05). Scoliosis Research Society Questionnaire 22 scores at 2 years were similar between the groups., Conclusion: Despite preoperatively smaller lumbar curves with less apical translation and lumbar prominence, most patients with selective fusions were out of balance postoperatively and had inferior radiographical outcomes as compared with their nonselective comparison cohort with similar patient-reported outcomes. Long-term follow-up is required to determine whether the trade-off of sparing motion segments at the expense of somewhat lessened radiographical outcomes is worthwhile.

Study Design: Retrospective review of prospectively collected surgical data., Objective: This study sought to determine the effect of fellow education during the course of the academic year (August-July) on surgical outcomes in adolescent idiopathic scoliosis. One surgeon and one type of surgery were chosen to minimize confounding factors., Summary of Background Data: Educating and training the next generation of physicians and surgeons is necessary for the survival and continuation of medical care. There has been recent momentum to document scientifically that medical education is safe. Spine surgery is complex and demanding, with a steep learning curve, making it an ideal model to detect any potential negative impact of medical education., Subjects: adolescent patients undergoing posterior spinal surgery, between August 2007 and July 2010, by a single senior surgeon at one institution with a fellow as the only surgical assistant. Demographic and perioperative data were collected and then segmented by surgical date into quarters according to the rotations of the academic year. One fellow was included in each quarter during the 4 years, resulting in 16 fellows across the 4 quarters. An analysis of variance model was used to assess differences in operative time, blood loss, length of stay, and complications between the quarters of the year., Results: There were no significant differences between the groups regarding age, sex, or Lenke curve type. No statistically significant differences were found between the 4 quarters of the fellowship year for estimated blood loss, use of cell saver, length of stay, operative time, and complication rate., Conclusion: This study is the first to show that fellow education during the course of the academic year did not impact the patient outcomes studied. It is clear that while there is significant academic benefit for the fellows as they complete their spine fellowship, there is no negative impact for patients., Level of Evidence: 4.

Study Design: Prospective, longitudinal cohort., Objective: To evaluate the incidence, timing, and risk factors for reoperation in patients with adolescent idiopathic scoliosis (AIS) treated with pedicle screws (PSs) compared with hybrid (Hb) constructs., Summary of Background Data: Rates of return to the operating room (OR) after definitive fusion for AIS vary, with a paucity of data on PS constructs., Methods: A prospective multicenter database was retrospectively queried to identify consecutive patients with AIS who underwent posterior spinal fusion with either PS or Hb constructs with a minimum 2-year follow-up. All reoperations were stratified into an early group (<60 d) or a late group (>60 d). Univariate and multivariate logistical analyses were performed to identify potential risk factors related to reoperation., Results: A total of 627 patients met the inclusion criteria (PS = 540, Hb = 87). There was a statistically significant difference in the rate of reoperations between the PS (3.5%) and Hb groups (12.6%), P < 0.001. Early return to the OR occurred in 2.0% of the patients with PS compared with 3.4% in the Hb group, P = 0.43. Late returns to the OR occurred in 1.5% of PS group versus 9.2% of the Hb group, P < 0.001. Multivariate analysis revealed longer operating time as an independent risk factor for an unplanned return to the OR in patients treated with PSs (P < 0.05)., Conclusion: Our results suggest that patients with AIS treated with PS have decreased rates of unplanned return to the OR when compared with patients with Hb constructs. The majority of returns to the OR were early (<60 d) for the PS group compared with late (>60 d) for the Hb group. Longer operative times increased the risk of unplanned reoperation for the PS group., Level of Evidence: 3.

Correct identification of fusion levels in surgical planning for the management of adolescent idiopathic scoliosis is a complex task. Several classification systems and algorithms exist to assist surgeons in determining the appropriate levels to be instrumented. The Lenke classification is the benchmark system. Among the many factors and measurements that are taken into account when selecting the proper upper instrumented vertebra and lower instrumented vertebra are planning for selective fusion; preserving motion segments; preventing proximal and/or distal junctional kyphosis, shoulder imbalance, and neck pain; and maintaining short fusion lengths. Existing treatment algorithms do not account for every exception, and further research is required to improve long-term surgical outcomes.

Background: Patient and surgical factors are known to influence operative blood loss in spinal fusion for adolescent idiopathic scoliosis (AIS), but have only been loosely identified. To date, there are no established recommendations to guide decisions to predonate autologous blood, and the current practice is based primarily on surgeon preference. This study is designed to determine which patient and surgical factors are correlated with, and predictive of, blood loss during spinal fusion for AIS., Methods: Retrospective analysis of 340 (81 males, 259 females; mean age, 15.2 y) consecutive AIS patients treated by a single surgeon from 2000 to 2008. Demographic (sex, age, height, weight, and associated comorbidities), laboratory (hematocrit, platelet, PT/PTT/INR), standard radiographic, and perioperative data including complications were analyzed with a linear stepwise regression to develop a predictive model of blood loss., Results: Estimated blood loss was 907±775 mL for posterior spinal fusion (PSF, n=188), 323±171 mL for anterior spinal fusion (ASF, n=124), and 1277±821 mL for combined procedures (n=28). For patients undergoing PSF, stepwise analysis identified sex, preoperative kyphosis, and operative time to be the most important predictors of increased blood loss (P<0.05). For ASF, the mean arterial pressure at incision and the operative time were predictive (P<0.05). The following formula was developed to estimate blood loss in PSF: blood loss (mL)=C+Op-time (min)×(6.4)-pre-op T2-T12 kyphosis (degrees)×(8.7), C=233 if male and -270 if female., Conclusion: We find sex, operative time, and preoperative kyphosis to be the most important predictors of increased blood loss in PSF for AIS. Mean arterial pressure and operative time were predictive of estimated blood loss in ASF. For posterior fusions, we also present a model that estimates blood loss preoperatively and can be used to guide decisions regarding predonation of blood and the use of antifibrinolytic agents., Level of Evidence: Retrospective study: Level II.

Object: In the surgical management of adolescent idiopathic scoliosis (AIS), patients are often preoperatively informed that they will gain height as a result of their surgery. However, current estimations conflict significantly and do not have any clinical correlation. The authors developed a formula that would predict postoperative gains in height after deformity correction in AIS., Methods: A large, multicenter, prospective database was retrospectively queried for AIS patients with Lenke Type 1, 2, or 3 curves having undergone posterior spinal fusion alone. A univariate and multivariate analysis was performed to identify which factors contributed significantly to changes in height., Results: Four hundred forty-seven patients were included in the series. Factors correlating with changes in postoperative height included: upper thoracic curve magnitude, main thoracic curve magnitude, lumbar curve magnitude, T2-12 kyphosis, T5-12 kyphosis, curve flexibility, number of levels fused, presence of Ponte osteotomies, total preoperative coronal Cobb angle, change in coronal curve magnitude, total preoperative sagittal curvature, change in sagittal curvature, and thoracic curve correction. When combined in a multivariate regression analysis the following variables remained significant: thoracic curve magnitude (p < 0.01), number of levels fused (p < 0.01), change in total sagittal curvature (p < 0.01), and the presence of osteotomies (p = 0.03). The contribution from the thoracic curve magnitude was significantly greater than any of the other parameters identified (R2 = 0.140). Change in height (in cm) = ([thoracic curve magnitude × 0.039] + [number of levels fused × 0.193] - [change in sagittal curvature × 0.033] + [x × 0.375]) - 1.858, where x = 1 if 1 or more osteotomies were performed and x = 0 if no osteotomy was performed., Conclusions: The authors' results suggest that changes in the coronal plane contribute more significantly to height changes than those in the sagittal plane and approximately 0.39 cm of height gain can be expected for each 10° of coronal curve preoperatively. Unfortunately, a significant fraction of the postoperative height changes cannot be predicted by currently measured parameters.

Study Design: Multicenter retrospective cohort study of 269 patients., Objective: The purpose of this study is to evaluate the surgical and radiographical factors in adolescent idiopathic scoliosis (AIS) surgery that significantly affect kyphosis maintenance., Summary of Background Data: Decreased kyphosis in the thoracic spine is a component of the 3-dimensional deformity in AIS. Suboptimal sagittal alignment after spinal fusion has been identified as a possible cause of lumbar and cervical spinal degeneration and junctional malalignment. Segmental spinal instrumentation continues to evolve, and although excellent coronal plane correction is readily achieved, sagittal plane thoracic hypokyphosis may be seen postoperatively., Methods: A retrospective analysis of prospectively collected data from a multicenter AIS database was performed to evaluate factors associated with kyphosis maintenance. A total of 526 patients were enrolled in the database and had a mean thoracic kyphosis (T5-T12) of 22°. In total, 269 patients were identified who had kyphosis of less than 22° and thus comprised the group to be included in this analysis. A complete radiographical series was obtained for each patient preoperatively, immediately postoperatively, and at 2 years postoperatively. All operative data, including the number of levels fused and implant type and density, were also recorded. Multivariate and regression analysis were performed., Results: Eight variables were found to be significantly correlated with kyphosis maintenance at 2 years postoperatively. Anterior approach (r = 0.37, P < 0.001), increased thoracic coronal curve (r = 0.20, P = 0.001), and a greater percentage of hooks in the construct (r = 0.18, P = 0.034) were associated with increased kyphosis at follow-up. A greater number of levels fused (r = -0.33, P < 0.001), preoperative kyphosis (r = -0.39, P < 0.001), percentage of screws in the construct (r = -0.18, P = 0.03), using standard stainless steel rods (r = -0.47, P = 0.011), and percent decrease in thoracic curve (r = -0.23, P < 0.001) all were correlated with hypokyphosis at follow-up., Conclusion: Our multivariate analysis demonstrates that in patients with AIS who have thoracic hypokyphosis as part of their deformity, certain factors must be taken into account in the preoperative planning to prevent hypokyphosis after surgical correction.

Study Design: In vitro cadaveric study., Objective: The purpose of this study was to quantify the relative biomechanical protection resulting from "saving a level" in long spinal fusions., Summary of Background Data: "Saving levels" in spinal deformity surgery is desirable. Constructs with lowest instrumented vertebra (LIV) in the lumbar spine may increase loads on unfused lumbar intervertebral discs, leading to accelerated disc degeneration. No study to date has quantified the relative pressure changes that occur in the unfused caudal discs with progressively longer fusions., Methods: We used a validated in vitro cadaveric long fusion model to assess intradiscal pressures (IDPs) below simulated fusions. Eight fresh frozen T8-S1 specimens were instrumented from T8 to L5. A follower-type loading system and 7.5-N·m moments were applied in flexion and extension. IDP profiles were assessed with a pressure transducer. After acquiring IDP measurements at a given construct length, the rod was cut 1 level higher until LIV = T12. IDP data from each unfused disc were averaged and normalized to the mean value of the disc when immediately subjacent to the LIV., Results: In both flexion and extension, the mean normalized IDP of the unfused discs below the LIV increased with increasing fusion length. For each 1-level increase in construct length, pressure increased by 3.2% ± 4.8% in flexion and 4.3% ± 4.5% in extension for each unfused disc. Although the differences in pressure for a given unfused disc with differing LIV were not significant, there were significant differences between unfused discs at a given LIV. With shorter fusion lengths, pressure in the disc immediately subjacent to the fusion was consistently greater than for the caudal-most discs., Conclusion: Unfused caudal lumbar discs experienced increased IDPs with increasing length of instrumentation, most notably at the subjacent discs closest to the LIV.

Study Design: Prospective radiographic evaluation of patients that underwent cervical total disc replacement (TDR-C) or anterior cervical discectomy and fusion (ACDF) for one-level cervical disc disease., Objective: To evaluate the following: (1) total cervical range of motion (ROM) from C2 to C7, and (2) the relative contribution to total cervical ROM from the operative level and each adjacent level after one-level TDR-C or ACDF., Summary of Background Data: The development of symptomatic adjacent segment disease after ACDF has served as the impetus for the development of motion-preserving alternatives, most notably cervical disc arthroplasty. While previous reports have evaluated device-level and total cervical motion, no study has comprehensively quantified the relative contribution made from each of the adjacent levels to total cervical ROM in TDR-C and ACDF., Methods: Radiographic review of 187 randomized patients from a multicenter, prospective, randomized trial comparing TDR-C with ACDF for one-level cervical disc disease. There were 93 TDR-C and 94 ACDF patients included. ROM measurements were performed independently using quantitative motion analysis, a custom digitized image stabilization software program, to evaluate total cervical ROM and relative contribution to total ROM from each level from C2 to C7 preoperatively and at 24 months., Results: The most common operative level was C5/C6 (57%) followed by C6/C7 (34%). At 2 years, the TDR-C group underwent a statistically greater improvement in total cervical ROM (+5.9°) compared with ACDF (-0.8°, P = 0.001). In TDR-C, the relative contributions to total cervical ROM from the operative level and each caudal and cranial adjacent level were statistically equivalent from baseline to 24 months. In contrast, ACDF patients had significantly reduced contribution to total cervical ROM from the operative level (by 15%, P < 0.001), and significantly elevated contribution from the caudal adjacent level (by 5.9%, P < 0.001), first cranial adjacent level (by 3.3%, P < 0.001), second cranial adjacent level (by 5.3%, P < 0.001), and third cranial adjacent level (by 3.0%, P < 0.001)., Conclusion: Compensation for the loss of motion at the operative level in ACDF is seen throughout the unfused cervical spine. Cervical disc arthroplasty, however, increases total cervical ROM compared with ACDF and maintains a physiologic distribution of ROM throughout the cervical spine at 2 years, potentially lowering the risk for adjacent segment breakdown.

Study Design: Retrospective analysis of prospectively collected data., Objective: To compare the relative rates of pulmonary recovery and maximal pulmonary function with surgical approach., Summary of Background Data: Anterior versus posterior spinal fusion (ASF, PSF) for the treatment of adolescent idiopathic scoliosis (AIS) has been debated. Although procedures that violate the chest wall may compromise pulmonary function, lung function continues to improve after surgery at variable rates depending upon surgical approach., Methods: We reviewed the medical records from one hundred fifty nine AIS patients (age 15.6±2.2; 113 women; 46 men) treated with spinal fusion from 2003 to 2007 by a single surgeon. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and radiographic measurements were evaluated before surgery and at 1, 3, 6, 12, and 24-months follow-up on average. Four surgical groups were compared: PSF, ASF (open thoracoabdominal approach for thoracolumbar curvature), video-assisted thoracoscopic surgical release with instrumentation (VATS-I), and VATS with PSF. FEV1 and FVC were fitted to model to evaluate the immediate postoperative pulmonary function (Yo), maximal recovery (Plateau), and rate (K) of pulmonary improvement., Results: Patients in each surgical subgroup were as follows: PSF (Lenke 1: n=50, Lenke 2,3: n=20), ASF (Lenke 5, n=35), VATS-I (Lenke 1=31, Lenke 3=1), and VATS+PSF (Lenke1: n=9, Lenke 2-6: n=13). Early postoperative pulmonary function was higher with ASF and PSF as compared to both VATS groups (P<0.05). Comparing all curve types, VATS-I showed a small decline of absolute FEV1 compared to PSF at 2-years follow-up. Comparing thoracic curves, however, no differences in FEV1 or FVC were noted at 6 to 12 months until 2-years follow-up. The rate of recovery (K) was equivalent for all surgical approaches and curve types., Conclusion: Compared to ASF or PSF, VATS procedures showed an initial decline in pulmonary function, which resolved fully by 6- to 12-months follow-up. Modest declines in maximal pulmonary function with VATS-I were seen when comparing all curve types together but not when comparing Lenke 1 curves alone. VATS procedures for thoracic scoliosis and open approaches for thoracolumbar curve types were associated with minimal to no permanent deficits.

Background: There is a continued role for anterior spinal fusion (ASF) in the treatment of thoracolumbar scoliosis. Despite numerous previous reports of ASF in the treatment of thoracolumbar scoliosis, no single study has simultaneously evaluated clinical, radiographic, and pulmonary function outcomes., Methods: Retrospective review of 31 consecutive thoracolumbar adolescent idiopathic scoliosis patients (Lenke type 5) who underwent ASF by a single surgeon. Patient records were comprehensively assessed for Scoliosis Research Society (SRS)-22 score, apical trunk rotation, radiographic changes, and pulmonary function before surgery and at 2-years follow-up., Results: Thoracolumbar/lumbar curve correction averaged from 45 to 11 degrees (74%) and spontaneous correction of thoracic curves averaged from 26 to 15 degrees (42%). Instrumented segment lordosis increased by 11 degrees, whereas proximal junction kyphosis increased by 3 degrees. No significant changes were noted in T2-T12 kyphosis, distal junctional kyphosis, T12-S1 lumbar lordosis, or coronal balance. Thoracolumbar apical trunk rotation improved from 12 to 3 degrees. Average SRS scores significantly improved from 3.9 to 4.4. SRS assessments of self-image and pain also improved significantly from 3.6 to 4.5 and from 4.1 to 4.6, respectively. Absolute and percent predicted forced vital capacity and forced expiratory volume in 1 second were unchanged. Two patients suffered mild intercostal neuralgia postthoracotomy. There were no other complications., Conclusions: The thoracoabdominal anterior approach for thoracolumbar scoliosis facilitates excellent clinical and radiographic outcomes, minimal blood loss, powerful apical trunk rotation correction, relative maintenance of lordosis, relatively short fusion constructs, and improved SRS-22 performance, without significant pulmonary function impairment at 2 years. It continues to be an efficacious treatment for thoracolumbar scoliosis., Level of Evidence: Level IV.

Background: Multilevel spinal fusion surgery has typically been associated with significant blood loss. To limit both the need for transfusions and co-morbidities associated with blood loss, the use of anti-fibrinolytic agents has been proposed. While there is some literature comparing the effectiveness of tranexamic acid (TXA) to epsilon aminocaproic acid (EACA) in cardiac procedures, there is currently no literature directly comparing TXA to EACA in orthopedic surgery., Methods/design: Here we propose a prospective, randomized, double-blinded control study evaluating the effects of TXA, EACA, and placebo for treatment of adolescent idiopathic scoliosis (AIS), neuromuscular scoliosis (NMS), and adult deformity (AD) via corrective spinal surgery. Efficacy will be determined by intraoperative and postoperative blood loss. Other clinical outcomes that will be compared include transfusion rates, preoperative and postoperative hemodynamic values, and length of hospital stay after the procedure., Discussion: The primary goal of the study is to determine perioperative blood loss as a measure of the efficacy of TXA, EACA, and placebo. Based on current literature and the mechanism by which the medications act, we hypothesize that TXA will be more effective at reducing blood loss than EACA or placebo and result in improved patient outcomes., Trial Registration: ClinicalTrials.gov ID: NCT00958581.

Study Design: Prospective radiographic and chart review of pulmonary function in patients who underwent 3 different anterior spinal surgery approaches for adolescent idiopathic scoliosis (AIS)., Objective: To assess the impact on pulmonary function in patients with AIS after anterior surgical approaches, including open thoracotomy, thoracoscopic with and without thoracoplasty, and thoracoabdominal 2 years after surgery., Summary of Background Data: Potential advantages of anterior surgery in the treatment of AIS include saving of distal motion segments and improving kyphosis restoration in the thoracic spine, possibly at the cost of pulmonary function impairment. Although thoracoscopic spinal instrumentation and fusion has recently been shown to induce less pulmonary impairment compared with open thoracotomy, no study has evaluated the effect of thoracoplasty as an adjunct to thoracoscopic surgery, nor the effects of the thoracoabdominal approach for thoracolumbar curvature., Methods: A multicenter spinal deformity database was queried for patients who underwent an anterior approach for either Lenke I or Lenke V idiopathic scoliosis. There were 68 patients in the thoracotomy group, 44 in the thoracoscopic group, and 19 in the thoracoabdominal group. Absolute and percent-predicted values of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and total lung capacity (TLC) were evaluated preoperatively and at 2-year follow-up, and comparisons were made within and between each group., Results: Comparing between groups at 2 years postoperatively, the thoracotomy group demonstrated significantly greater decreases (-10.97% and -12.97%) in both percent-predicted FEV1 and FVC, respectively, when compared with the thoracoscopic group (-4.40% and -4.73%), respectively. Percent-predicted TLC in the thoracoscopic group increased (3.19%), but decreased in the thoracotomy group (-8.00%). Subanalysis of the thoracoscopic group at 2 years revealed that the addition of a thoracoplasty (3 to 5 ribs) significantly reduced percent-predicted FEV1 (-11.6%, P = 0.0013) and percent-predicted FVC (-16.0%, P = 0.017) from baseline. Patients who underwent thoracoscopy alone without a thoracoplasty experienced no significant detrimental changes in these parameters at 2 years, and instead experienced significant increases in absolute TLC (P < 0.001) and percent-predicted TLC (P = 0.035). There were no significant changes demonstrated in the thoracoabdominal group for all 3 parameters., Conclusions: Slight declines in pulmonary function at 2-year follow-up were noted in both the thoracotomy and thoracoscopic groups, but to a significantly greater extent in those with an open thoracotomy. Significantly greater impairment in pulmonary function was seen in thoracoscopic patients who underwent thoracoplasty, whereas those without thoracoplasty either had no significant declines at 2 years or experienced slight but significant improvement. No significant diminishment was noted for the thoracoabdominal approach, despite disruption of the diaphragm.

Study Design: Retrospective review., Objective: The purpose of this study is to evaluate the learning curve and associated evolution in surgical technique with thoracic pedicle screw instrumentation in adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Common treatment for AIS now includes posterior spinal fusion, using thoracic pedicle screws (TPS). It is critical to assess the efficacy, safety profile, and learning curve associated with this technique as its use becomes more widespread among inexperienced surgeons., Methods: Retrospective review of the senior author's first 96 TPS cases for Lenke Type I AIS curves. Multiple regression techniques were used to discern whether increasing case number (CN) was associated with improved perioperative and 2-year minimum radiographic and clinical outcomes. The 96 cases were divided into 4 equal quartiles of 24 cases/group (i.e., Q1-Q4) and compared using analysis of variance measures., Results: A total of 1169 thoracic pedicle screws were placed in 96 patients. We found a significant correlation between CN and major curve correction at 2 years (P < 0.0001), inverse correlation between CN and length of stay (P = 0.02), and estimated blood loss (P = 0.03), but no differences in cell saver or complications. Univariate analysis revealed significant inverse correlations between increasing CN and transfusion rate (P = 0.02) and operative times (P = 0.0001). Total number of screws placed (Q1:9.4 vs. Q4:16.2, P < 0.0001) and number of screws/level (Q1:0.98 vs. Q4:1.64, P < 0.0001) increased linearly with increasing CN, whereas the average time for screw placement (Q1:24.2 vs. Q4:11.4 minutes, P < 0.0001) and ability to maintain T2-T12 kyphosis decreased (Q1:0.21 vs. Q4:-5.5 P = 0.02) with increasing CN., Conclusion: There is a significant learning curve associated with thoracic pedicle screw placement in AIS. We describe several technical steps that can be taken to increase the safety of screw placement at the beginning of the learning curve. Inexperienced surgeons should expect a gradual improvement over time in radiographic and clinical outcomes.

Study Design: Radiographic results of a multicenter, prospective randomized study comparing 1-level cervical total disc replacement (TDR-C) with anterior cervical discectomy and fusion (ACDF)., Objective: To evaluate the effect on device-level lordosis, cranial and caudal adjacent level lordosis, and overall cervical sagittal alignment (C2-C6) after TDR-C or ACDF., Summary of Background Data: Cervical total disc replacement (TDR-C) has emerged as a promising alternative to ACDF in a select group of patients. The maintenance and/or improvement of sagittal balance is essential in preserving functionality after reconstructive spinal procedures. Recent studies have documented changes in spinal alignment after TDR-C, however, no studies have compared these changes to those noted in matched group of patients that have undergone ACDF., Methods: Radiographic data were obtained from the randomized group of a multicenter, randomized, prospective, controlled study comparing TDR-C (ProDisc-C, Synthes Spine, West Chester, PA) with ACDF in the treatment of 1-level cervical disc disease. Complete radiographic data were available for 89 TDR-C patients (average age: 42.2 years) and 91 ACDF patients (average age: 41.7 years). Cervical lordosis at the device level, cranial and caudal adjacent levels, and total cervical lordosis (C2-C6) were independently measured before surgery and 2 years after surgery using custom image stabilization software (Quantitative Motion Analysis, Medical Metrics, Inc, Houston, TX)., Results: C5-C6 was the most common operative level (TDR-C: 54%; ACDF: 55%). At 2 years after surgery, the TDR-C group experienced statistically significant changes in lordosis of 3.0 degrees (P < 0.001), 0.90 degrees (P = 0.006), and -1.9 degrees (P < 0.001) at the operative, cranial, and caudal adj-acent levels, respectively. ACDF experienced changes in lordosis of 4.2 degrees (P < 0.001), 1.0 degrees (P = 0.001), and -1.5 degrees (P = 0.001), respectively. The between-group differences were significant at the operative level (P = 0.03) and the caudal adjacent level (P = 0.05). Total cervical lordosis increased in both TDR-C and ACDF by 3.1 degrees and 3.8 degrees , respectively (P = 0.49)., Conclusion: In both TDR-C and ACDF, lordosis increased at the device-level, cranial adjacent level, and in total cervical lordosis, while lordosis decreased at the caudal adjacent level. Although ACDF facilitated a greater increase in device level lordosis (+1.25 degrees ) and less loss of lordosis at the caudal adjacent level compared with TDR-C (-0.39 degrees ), the clinical relevance of the small differences remain unknown.

Background Context: Anterior fusion through an open thoracotomy restores kyphosis more reliably than posterior techniques in patients with thoracic adolescent idiopathic scoliosis (AIS). Video-assisted thoracoscopic spinal fusion and instrumentation (VATS) minimizes the morbidity, from soft tissue and muscle dissection that accompanies traditional open thoracotomy. To our knowledge, there has not been a comprehensive analysis of VATS with respect to radiographic and clinical outcomes in the sagittal plane., Purpose: To measure the radiographic and clinical outcomes after VATS with emphasis on the sagittal plane., Study Design/setting: A retrospective, radiographic review of 26 consecutive patients with Lenke type-I AIS who underwent VATS., Methods: Radiographs of 26 consecutive patients with Lenke type-I AIS curves operated by a single surgeon were retrospectively reviewed after VATS. Sagittal and coronal parameters were compared with reported data for open anterior and posterior procedures., Results: There was an increase in kyphosis from baseline to final follow-up by 6.6 degrees (25%) from T2 to T12 (p<.0001), 8.7 degrees (50%) from T5 to T12 (p<.0001), and 8 degrees (54%) in the instrumented segment (p<.0001). Junctional kyphosis did not occur. No differences were detected in sagittal measurements between the first postoperative erect and the final radiographs. Patients experienced significant improvements from baseline to 2 years in Scoliosis Research Society-22 Health-Related Quality-of-Life Outcome Questionnaire scores (p<.0001)., Conclusions: Video-assisted thoracoscopic spinal fusion and instrumentation, in agreement with results reported for open anterior instrumentation, reliably restores or increases thoracic kyphosis while preserving junctional alignment in thoracic AIS.