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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Multicenter retrospective cohort study of 100 consecutive patients. OBJECTIVE: Compare the coronal and sagittal plane radiographic outcomes and clinical rib hump deformity correction in patients who underwent posterior spinal fusion for adolescent idiopathic scoliosis using hybrid instrumentation, polyaxial (POLY) segmental pedicle screw fixation, or monoaxial (MONO) segmental pedicle screw fixation. SUMMARY OF BACKGROUND DATA: Instrumentation for the treatment of scoliosis has evolved. Current techniques include use of a combination of hooks, sublaminar wires, and pedicle screws (HYBRID), as well as segmental pedicle screw fixation with either monoaxial or polyaxial screw anchors. METHODS: Data were obtained from a multicenter prospective database registry. Radiographic assessment was performed from radiographs taken before surgery and 2 years after surgery. Intraoperative parameters assessed included operative time, estimated blood loss, and whether or not a thoracoplasty was performed. Clinical evaluation of the angle of trunk rotation was done with an inclinometer. RESULTS: Preoperative thoracic curvature and curve flexibility, age, Lenke curve type, and number of levels fused was similar for each group. Significantly more anchors per level were used in the MONO group (1.69) and in the HYBRID group (1.24) compared to the POLY group (1.06). There were no statistical differences among the groups with respect to major thoracic curve correction (MONO: 69%; POLY: 68%; HYBRID: 62%, P = 0.22). POLY constructs maintained thoracic kyphosis, whereas MONO and HYBRID had a tendency toward loss of thoracic kyphosis and there was a trend toward a greater percent thoracic angle of trunk rotation correction in the MONO group (55%) compared with the POLY group (32%, P = 0.10), but no differences compared with Hybrid (55%, P > 0.05). CONCLUSION: Similar coronal and sagittal plane correction was achieved in thoracic adolescent idiopathic scoliosis with 3 different constructs. There was a trend toward improved correction of clinical rib hump deformity with MONO screw constructs compared with POLY screw constructs. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective, matched cohort. Objective: The purpose of this study was to compare the Scoliosis Research Society's Outcomes measures (SRS-22) scores, as well as radiographic outcomes of patients with adolescent idiopathic scoliosis who had a single thoracic structural curvature treated by either posterior spinal fusion (PSF) or video-assisted thoracoscopic (VATS) fusion. Summary Of Background Data: To our knowledge, there has been no prior matched-pair study comparing outcomes between 2 different surgical approaches for the same curve type using the SRS-22 outcomes instrument. Methods: Patients were evaluated before surgery and at 2-year follow-up. A total of 52 patients with Lenke type I curvature were paired by age, gender, and major Cobb angle into 2 groups: PSF (8 men, 18 women, mean age 14.7, mean Cobb angle 48.7) and VATS (mean age 14.8, mean Cobb angle 49.1). All questionnaire scores were classified based on domains of activity, pain, self-image, mental health, satisfaction, and total scores. Results: The patients in the VATS group scored higher than the PSF group in the domains of self-image (P < 0.02), mental health (P < 0.03), and total score (P < 0.05), but not activity, pain, or satisfaction at 2 years. There was no difference in percent curve correction between the match-paired groups. Within-group analyses revealed that VATS patients experienced insignificant improvements compared with PSF in most SRS-22 domains and a trend toward significant overall mean score improvement (P = 0.06). Conclusion: Based on the SRS-22 questionnaire data, the VATS patients scored higher in the self-image, mental health, and total domains despite similar curve corrections. We hypothesize that this may be related to the smaller surgical scar and less invasive nature of VATS. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective multicenter review of 78 patients with Scheuermann's kyphosis treated operatively was conducted. Objective: The purpose of this study was to evaluate correction of sagittal alignment, maintenance of correction, and occurrence of, and etiologic factors associated with, junctional kyphosis in patients managed operatively for Scheuermann's kyphosis. Summary Of Background Data: There is a paucity of literature regarding the surgical treatment of Scheuermann's kyphosis using current implant systems and operative techniques. Junctional kyphosis has been shown to occur in up to one third of patients. Factors causing junctional kyphosis have not been clearly elucidated. Loss of correction has been variable based on the technique used. No clear-cut advantages or disadvantages have been shown for the use of anterior release. Methods: Kyphosis, lordosis, C7 sagittal plumbline, apical translation, junctional sagittal alignment, and pelvic incidence were assessed among other radiographic parameters from a centralized database. The incidence of junctional kyphosis and its association to the above parameters and to fusion levels were assessed. Complication rates and differences between patients undergoing combined anteroposterior surgery and those having posterior surgery alone were evaluated. Results: Of the 78 patients, 42 underwent combined anteroposterior procedures (Group 1) and 36 had posterior surgery only (Group 2). Mean age was 16.7 years. Overall, the greatest Cobb kyphosis of 78.8 degrees was corrected to 51.4 degrees at follow-up. Preoperative kyphosis was 82.6 degrees and 74.4 degrees for Groups 1 and 2, respectively (P < 0.001) and 55.8 degrees and 46.2 degrees at follow-up (P = 0.000). Loss of correction was 3.2 degrees (not significant) and 6.4 degrees (P = 0.000), respectively. Lordosis corrected from -65.5 degrees to -51.7 degrees . Proximal and distal junctional kyphosis of >or=10 degrees occurred in 25 (32.1%) and 4 (5.1%), respectively. The development of a proximal junctional kyphosis correlated directly with kyphosis at follow-up and indirectly with percent correction. Among patients with proximal junctional kyphosis, the magnitude of junctional kyphosis correlated directly with the degree of pelvic incidence. Pelvic incidence correlated directly with lumbar lordosis but not kyphosis. Twelve complications occurred in 12 patients, including posterior wound infection (1), distal (2), and proximal (1) junctional kyphosis, and pseudarthrosis (1), those requiring reoperation. Conclusion: This is one of the largest reported series of Scheuermann's kyphosis treated operatively to our knowledge. A high rate of junctional kyphosis, especially at the proximal end, is associated with surgery for Scheuermann's kyphosis using current techniques. Proximal junctional kyphosis is associated with higher magnitude of kyphosis at follow-up, less percent correction; its magnitude correlated directly with pelvic incidence. Loss of correction is less in patients undergoing combined anteroposterior surgery. Pelvic incidence correlates directly with lordosis but not kyphosis, suggesting that these parameters are not causative of Scheuermann's kyphosis. [ABSTRACT FROM AUTHOR]

Background: Posterior spinal fusion with segmental instrumentation is the gold standard for the surgical treatment of thoracic adolescent idiopathic scoliosis. More recently, anterior surgery and video-assisted thoracoscopic surgery with spinal instrumentation have become an option. The purpose of the present study was to compare the radiographic and clinical outcomes as well as pulmonary function in patients managed with either anterior thoracoscopic or posterior surgery.Methods: Radiographic data, Scoliosis Research Society patient-based outcome questionnaires, pulmonary function, and operative records were reviewed for fifty-one patients undergoing surgical treatment of scoliosis. Data were collected preoperatively, immediately postoperatively, and at the time of the final follow-up. The radiographic parameters that were analyzed included coronal curve correction, the most caudad instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis. The operative parameters that were evaluated included the operative time, the estimated blood loss, the blood transfusion rate, the number of levels fused, the type of bone graft used, and the number of intraoperative and postoperative complications. The pulmonary function parameters that were analyzed included vital capacity and peak flow.Results: The thoracoscopic group included twenty-eight patients with a mean age of 14.6 years, and the posterior fusion group included twenty-three patients with a mean age of 14.3 years. The percent correction was 54.5% for the thoracoscopic group and 55.3% for the posterior group. With the numbers available, there were no significant differences between the two groups in terms of kyphosis (p = 0.84), coronal balance (p = 0.70), or tilt angle (p = 0.91) at the time of the final follow-up. The mean number of levels fused was 5.8 in the thoracoscopic group, compared with 9.3 levels in the posterior group (p < 0.0001). The estimated blood loss in the thoracoscopic group was significantly less than that in the posterior fusion group (361 mL compared with 545 mL; p = 0.03), and the transfusion rate in the thoracoscopic group was significantly lower than that in the posterior fusion group (14% compared with 43%; p = 0.01). Operative time in the thoracoscopic group was significantly greater than that in the posterior group (6.0 compared with 3.3 hours, p < 0.0001). There were no intraoperative complications in either group. Vital capacity and peak flow had returned to baseline levels in both groups at the time of the final follow-up. Patients in the thoracoscopic group scored higher than those in the posterior group in terms of the total score (p < 0.0001) and all of the domains (p < 0.01) of the Scoliosis Research Society questionnaire at the time of the final follow-up.Conclusions: Thoracoscopic spinal instrumentation compares favorably with posterior fusion in terms of coronal plane curve correction and balance, sagittal contour, the rate of complications, pulmonary function, and patient-based outcomes. The advantages of the procedure include the need for fewer levels of spinal fusion, less operative blood loss, lower transfusion requirements, and improved cosmesis as a result of small, well-hidden incisions. However, the operative time for the thoracoscopic procedure was nearly twice that for the posterior approach. Additional study is needed to determine the precise role of thoracoscopic spinal instrumentation in the treatment of thoracic adolescent idiopathic scoliosis. [ABSTRACT FROM AUTHOR]

Background: Posterior spinal fusion with segmental instrumentation is the gold standard for the surgical treatment of thoracic adolescent idiopathic scoliosis. More recently, anterior surgery and video-assisted thoracoscopic surgery with spinal instrumentation have become available. The purpose of the present study was to compare the radiographic and clinical outcomes as well as pulmonary function in patients managed with either anterior thoracoscopic or posterior surgery.Methods: Radiographic data, Scoliosis Research Society patient-based outcome questionnaires, pulmonary function, and operative records were reviewed for fifty-one patients undergoing surgical treatment of scoliosis. Data were collected preoperatively, immediately postoperatively, and at the time of the final follow-up. The radiographic parameters that were analyzed included coronal curve correction, the most caudad instrumented vertebra tilt angle correction, coronal balance, and thoracic kyphosis. The operative parameters that were evaluated included the operative time, the estimated blood loss, the blood transfusion rate, the number of levels fused, the type of bone graft used, and the number of intraoperative and postoperative complications. The pulmonary function parameters that were analyzed included vital capacity and peak flow.Results: The thoracoscopic group included twenty-eight patients with a mean age of 14.6 years, and the posterior fusion group included twenty-three patients with a mean age of 14.3 years. The percent correction was 54.5% for the thoracoscopic group and 55.3% for the posterior group. With the numbers available, there were no significant differences between the two groups in terms of kyphosis (p = 0.84), coronal balance (p = 0.70), or tilt angle (p = 0.91) at the time of the final follow-up. The mean number of levels fused was 5.8 in the thoracoscopic group, compared with 9.3 levels in the posterior group (p < 0.0001). The estimated blood loss in the thoracoscopic group was significantly less than that in the posterior fusion group (361 mL compared with 545 mL; p = 0.03), and the transfusion rate in the thoracoscopic group was significantly lower than that in the posterior fusion group (14% compared with 43%; p = 0.01). Operative time in the thoracoscopic group was significantly greater than that in the posterior group (6.0 compared with 3.3 hours, p < 0.0001). There were no intraoperative complications in either group. Vital capacity and peak flow had returned to baseline levels in both groups at the time of the final follow-up. Patients in the thoracoscopic group scored higher than those in the posterior group in terms of the total score (p < 0.0001) and all of the domains (p < 0.01) of the Scoliosis Research Society questionnaire at the time of the final follow-up.Conclusions: Thoracoscopic spinal instrumentation compares favorably with posterior fusion in terms of coronal plane curve correction and balance, sagittal contour, the rate of complications, pulmonary function, and patient-based outcomes. The advantages of the procedure include the need for fewer levels of spinal fusion, less operative blood loss, lower transfusion requirements, and improved cosmesis as a result of small, well-hidden incisions. However, the operative time for the thoracoscopic procedure was nearly twice that for the posterior approach. Additional study is needed to determine the precise role of thoracoscopic spinal instrumentation in the treatment of thoracic adolescent idiopathic scoliosis. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective review of clinical and radiographic data from a multicenter adolescent idiopathic scoliosis (AIS) database. OBJECTIVE.: The purpose of this study was to perform a comprehensive radiographic evaluation of the differences in pelvic parameters between 2 groups (white and black) in a scoliotic population. Summary Of Background Data: Increasingly, the importance of spinopelvic alignment and balance is appreciated as a major factor in the energy-efficient posture of the individual in the normal and diseased states. Pelvic incidence (PI) determines the lordosis of the patient and equations defining the interplay of pelvic parameters, lordosis, and kyphosis have been developed to guide surgical decision-making for spinal deformity. PI and thoracic lordosis have been previously shown to be increased in the AIS population. Methods: Data were obtained from a prospective multicenter AIS database from a total of 1658 patients. We evaluated the 2 largest racial subsets in our database. We identified 421 whites and 115 black patients who met inclusion criteria. The parameters evaluated on preoperative full-length coronal and lateral radiographs were PI, sacral slope (SS), pelvic tilt, lumbar lordosis (LL), thoracic kyphosis, sagittal Cobb angle, and the shift of the sagittal C7 plumb line. Results: Age, gender, major and minor cobb angles were similar in the 2 groups. PI, pelvic tilt, and LL were found to be significantly greater in the black group when compared with the white group (black: 56.0, 13.9, and -63.6 vs. white: 52.5, 10.8, and -59.1). Conclusion: In our study, significant differences were found in 3 of the 6 sagittal plane parameters between the 2 groups. With a larger PI, a larger LL is required in order maintain a neutral sagittal balance. Our results suggest that race may influence an individual's natural spinopelvic alignment, and serves as a reminder when planning surgical reconstruction for spinal deformity. [ABSTRACT FROM AUTHOR]

Purpose: Adolescent Idiopathic Scoliosis (AIS) remains the most common type of pediatric scoliosis, mostly affecting children between ages 10 and 18. Vertebral body tethering (VBT) offers a non-fusion alternative to the gold standard spinal fusion that permits flexibility and some growth within instrumented segments. This article will serve as a comprehensive literature review of the current state-of-the-art of VBT in relation to radiographic and clinical outcomes, complications, and the learning curve associated with the procedure., Methods: A systematic literature review was conducted on PubMed, Scopus, and Web of Science from April 2002 to December 2022. Studies were included if they discussed VBT and consisted of clinical studies in which a minimum 2-years follow-up was reported, and series that included anesthetic considerations, learning curve, and early operative morbidity., Results: Forty-nine studies spanning the period from April 2002 to December 2022 were reviewed., Conclusion: This article illustrates the potential benefits and challenges of the surgical treatment of AIS with VBT and can serve as a basis for the further study and refinement of this technique ideally as a living document that will be updated regularly., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

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.)

Purpose: The treatment of operative double major pediatric spinal deformities (e.g., Lenke 3 or 6) with bilateral vertebral body tethering (VBT) can be significantly more challenging when compared to other deformity patterns (e.g., Lenke 1) or treatment with a posterior spinal fusion. We aimed to identify preoperative and perioperative characteristics that were associated with successful postoperative outcomes in patients treated with both a thoracic and thoracolumbar (e.g., bilateral) tether., Methods: We retrospectively assessed radiographic and clinical data from patients enrolled in a large multi-center study who had a minimum postoperative follow-up of two years. Standard radiographic parameters were extracted from standing spine and left hand-wrist radiographs at various timepoints. We classified patients based on their preoperative deformity pattern (Primary Thoracic [T P ] vs. Primary Thoracolumbar [TL P ]) and assessed: (1) deformity balance, (2) tilt of the transitional vertebra, and (3) postoperative success., Results: We analyzed data from thirty-six patients (T P : 19 and TL P : 17). We observed no relationship between deformity balance at first erect and postoperative success (p = 0.354). Patients with a horizontal transitional vertebra at first erect were significantly (p = 0.001) more likely to exhibit a successful outcome when compared to those who exhibited a tilted transitional vertebra (83% vs. 62%). Patients who had TL P were also more likely to exhibit a successful outcome when compared to patients who exhibited T P (76% vs. 50%)., Conclusion: These data indicate that double major deformities can be successfully treated with VBT, particularly for those who exhibit TL P ., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

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: Little data exist on pregnancy and childbirth for adolescent idiopathic scoliosis (AIS) patients treated with a spinal fusion. The current literature relies on data from patients treated with spinal fusion techniques and instrumentation, such as Harrington rods, that are no longer in use. The objective of our study is to understand the effects of spinal fusion in adolescence on pregnancy and childbirth., Methods: Prospectively collected data of AIS patients undergoing posterior spinal fusion that were enrolled in a multicenter study who have had a pregnancy and childbirth were reviewed. Results were summarized using descriptive statistics and compared with national averages using χ 2 test of independence., Results: A total of 78 babies were born to 53 AIS patients. As part of their pre-natal care, 24% of patients surveyed reported meeting with an anesthesiologist before delivery. The most common types of delivery were spontaneous vaginal delivery (46%, n=36/78) and planned cesarean section (20%, n=16/78). Compared with the national average, study patients had a higher rate of cesarean delivery ( P =0.021). Of the women who had a spontaneous vaginal birth, 53% had no anesthesia (n=19/36), 19% received intravenous intermittent opioids (n=7/36), and 31% had regional spinal or epidural anesthesia (n=11/36). spontaneous vaginal delivery patients in our study cohort received epidural or spinal anesthesia less frequently than the national average ( P <0.001). Of those (n=26 pregnancies) who did not have regional anesthesia (patients who had no anesthesia or utilized IV intermittent opioids), 19% (n=5 pregnancies) were told by their perinatal providers that it was precluded by previous spine surgery., Conclusion: The majority of AIS patients reported not meeting with an anesthesiologist before giving birth and those who had a planned C-section did so under obstetrician recommendation. The presence of instrumentation after spinal fusion should be avoided with attempted access to the spinal canal but should not dictate a delivery plan. A multidisciplinary team consisting of obstetrician, anesthesiologist, and orthopaedic surgeon can provide the most comprehensive information to empower a patient to make her decisions regarding birth experience anesthesia based on maternal rather than provider preference., Level of Evidence: IV., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Thoracic spinal deformities may reduce chest wall compliance, leading to respiratory complications. The first SARS-CoV-2 (L-variant) strain caused critical respiratory illness, especially in vulnerable patients. This study investigates the association between scoliosis and SARS-CoV-2 (COVID-19) disease course severity., Methods: Clinical data of 129 patients treated between March 2020 to June 2021 who received a positive COVID-19 polymerase chain reaction result from Mount Sinai and had a scoliosis ICD-10 code (M41.0-M41.9) was retrospectively analyzed. Degree of coronal plane scoliosis on imaging was confirmed by 2 independent measurers and grouped into no scoliosis (Cobb angle <10°), mild (10°-24°), moderate (25°-39°), and severe (>40°) cohorts. Baseline characteristics were compared, and a multivariable logistic regression controlling for clinically significant comorbidities examined the significance of scoliosis as an independent risk factor for hospitalization, intensive care unit (ICU) admission, acute respiratory distress syndrome (ARDS), mechanical ventilation, and mortality., Results: The no (n = 42), mild (n = 14), moderate (n = 44), and severe scoliosis (n = 29) cohorts differed significantly only in age (P = 0.026). The percentage of patients hospitalized (P = 0.59), admitted to the ICU (P = 0.33), developing ARDS (P = 0.77), requiring mechanical ventilation (P = 1.0), or who expired (P = 0.77) did not significantly differ between cohorts. The scoliosis cohorts did not have a significantly higher likelihood of hospital admission (mild P = 0.19, moderate P = 0.67, severe P = 0.98), ICU admission (P = 0.97, P = 0.94, P = 0.22), ARDS (P = 0.87, P = 0.74, P = 0.94), mechanical ventilation (P = 0.73, P = 0.69, P = 0.70), or mortality (P = 0.74, P = 0.87, P = 0.66) than the no scoliosis cohort., Conclusions: Scoliosis was not an independent risk factor for critical COVID-19 illness. No trends indicated any consistent effect of degree of scoliosis on increased adverse outcome likelihood., (Copyright © 2023 Elsevier 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: Durability of outcomes following vertebral body tethering (VBT) is a concern and may be impacted by tether breakage (TB), which has been unstudied in a large cohort. We characterized TB rates and their impact on clinical outcomes in the largest single-surgeon series to date., Methods: Inclusion criteria were VBT patients with AIS, major Cobb angle ≤ 75°, and minimum 2-year follow-up (FU). TBs were identified on 1- and 2-year FU X-rays. TB rates between single-cord and double-cord tethers were evaluated using two-proportion z test. Curve correction rates and SRS-22 scores between patients with and without TB at 2 years were evaluated using Mann-Whitney U test., Results: 69 patients were included. By 2-year FU, 18 (27%) had experienced TB. TB primarily occurred in major (70%) versus minor curves and thoracolumbar tethers (75%) versus thoracic. TB rates between thoracolumbar single (32%) and double-cord tethers (30%) were not significantly different (p = 0.88). Mean major curve correction at 2-year FU was lower (p = 0.02) in patients with major curve TB (48° to 24°, 50%) versus those without (53°-21°, 60%). 2 patients (3%) required reoperation, 1 due to foraminal encroachment from a screw tip and 1 for curve progression with TB., Conclusion: TB rate was 27% at 2 years following VBT. Broken major curve tethers are associated with minor loss of correction that may not be clinically significant. TB rates are higher for thoracolumbar curvatures and double cords may not be protective against TB. Further study of long-term TB rates is imperative., Level of Evidence: IV., (© 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: A multicenter, prospectively collected database of 20 years of operatively treated adolescent idiopathic scoliosis (AIS) was utilized to retrospectively examine pre- and postoperative thoracic kyphosis at 2-year follow-up., Objective: To determine if the adoption of advanced three-dimensional correction techniques has led to improved thoracic kyphosis correction in AIS., Summary of Background Data: Over the past 20 years, there has been an evolution of operative treatment for AIS, with more emphasis on sagittal and axial planes. Thoracic hypokyphosis was well treated with an anterior approach, but this was not addressed sufficiently in early posterior approaches. We hypothesized that patients with preoperative thoracic hypokyphosis prior to 2000 would have superior thoracic kyphosis restoration, but the learning curve with pedicle screws would reflect initially inferior restoration and eventual improvement., Methods: From 1995 to 2015, 1063 patients with preoperative thoracic hypokyphosis (<10°) were identified. A validated formula for assessing three-dimensional sagittal alignment using two-dimensional kyphosis and thoracic Cobb angle was applied. Patients were divided into 1995-2000 (Period 1, primarily anterior), 2001-2009 (Period 2, early thoracic pedicle screws), and 2010-2015 (Period 3, modern posterior) cohorts. Two-way repeated measures analysis of variance and post-hoc Bonferroni corrections were utilized with P < 0.05 considered significant., Results: Significant differences were demonstrated. Period 1 had excellent restoration of thoracic kyphosis, which worsened in Period 2 and improved to near Period 1 levels during Period 3. Period 3 had superior thoracic kyphosis restoration compared with Period 2., Conclusion: Although the shift from anterior to posterior approaches in AIS was initially associated with worse thoracic kyphosis restoration, this improved with time. The proportion of patients restored to >20° kyphosis with a contemporary posterior approach has steadily improved to that of the era when anterior approaches were more common., Level of Evidence: 3.

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.

Study Design: Survey., Objectives: Bracing is the mainstay of conservative treatment in Adolescent Idiopathic Scoliosis (AIS). The purpose of this study was to establish best practice guidelines (BPG) among a multidisciplinary group of international bracing experts including surgeons, physiatrists, physical therapists, and orthotists utilizing formal consensus building techniques. Currently, there is significant variability in the practice of brace treatment for AIS and, therefore, there is a strong need to develop BPG for bracing in AIS., Methods: We utilized the Delphi process and the nominal group technique to establish consensus among a multidisciplinary group of bracing experts. Our previous work identified areas of variability in brace treatment that we targeted for consensus. Following a review of the literature, three iterative surveys were administered. Topics included bracing goals, indications for starting and discontinuing bracing, brace types, brace prescription, radiographs, physical activities, and physiotherapeutic scoliosis-specific exercises. A face-to-face meeting was then conducted that allowed participants to vote for or against inclusion of each item. Agreement of 80% throughout the surveys and face-to-face meeting was considered consensus. Items that did not reach consensus were discussed and revised and repeat voting for consensus was performed., Results: Of the 38 experts invited to participate, we received responses from 32, 35, and 34 for each survey, respectively. 11 surgeons, 4 physiatrists, 8 physical therapists, 3 orthotists, and 1 research scientist participated in the final face-to-face meeting. Experts reached consensus on 67 items across 10 domains of bracing which were consolidated into the final best practice recommendations., Conclusions: We believe that adherence to these BPG will lead to fewer sub-optimal outcomes in patients with AIS by reducing the variability in AIS bracing practices, and provide a framework future research., Level of Evidence: Level IV.

Background: Severe, rigid thoracolumbar scoliosis presents a surgical challenge to achieve 3-dimensional correction, maximize distal motion segments, and avoid operative morbidity conferred by combined anterior-posterior approaches or 3-column osteotomies. We present a new approach for releasing these curves, using multilevel posterolateral convex disc release (PCDR) and posterior instrumented fusion., Methods: There were 3 adults and 1 adolescent (mean age, 31.8 years; 2 females) with severe progressive thoracic and transforaminal lumbar (major) idiopathic scoliosis (IS) who were treated with 3-level PCDR, multiple posterior column osteotomies, and posterior instrumented thoracolumbar fusion with all-pedicle screw constructs., Results: Restoration of global coronal and sagittal alignment was achieved for all patients (minimum 2-year follow-up). Lowest instrumented vertebra (LIV) was L4 in 2 patients and L3 in the remaining 2. All except 1 were fused to the lower end vertebra. Postoperatively, mean thoracolumbar curve was reduced from 77.3° (range, 69°-91°) to 21.8° (72%Δ), LIV tilt decreased from 26.8° to 8.3°, and LIV translation improved (2.5-1.2 cm; 58%Δ), whereas lumbar lordosis remained unchanged. Average central sacral vertical line shift measured via C7 sagittal vertical axis changed from 1.4 to -0.7 cm. There were no complications except for dysesthesias in the lower extremity on the side of the PCDR in 1 patient, which resolved after 3 months., Conclusions: Severe thoracolumbar IS presents a surgical challenge to achieve 3-dimensional correction, minimize fusion levels, and avoid procedural morbidity. PCDR is a novel technique that may facilitate this correction with minimal procedure-related morbidity., Competing Interests: Disclosures and COI: The authors received no funding for this study and report no conflicts of interest., (©International Society for the Advancement of Spine Surgery 2020.)

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.

Objective: A posterior dynamic deformity correction (PDDC) system was used to correct adolescent idiopathic scoliosis (AIS) without fusion. The preliminary outcomes of bridging only 3-4 discs in patients with variable curve severity have previously been reported. This paper examines a subgroup of patients with the authors' proposed current indications for this device who were also treated with a longer construct., Methods: Inclusion criteria included a single AIS structural curve between 40° and 60°, curve flexibility ≤ 30°, PDDC spanning 5-6 levels, and minimum 2-year follow-up. A retrospective review was conducted and demographic and radiographic data were recorded. A successful outcome was defined as a curve magnitude of ≤ 30° at final follow-up. Any serious adverse events and reoperations were recorded., Results: Twenty-two patients who met the inclusion criteria were operated on with the PDDC in 5 medical centers. There were 19 girls and 3 boys, aged 13-17 years, with Risser grades ≥ 2. Thirteen had Lenke type 1 curves and 9 had type 5 curves. The mean preoperative curve was 47° (range 40°-55°). At a minimum of 2 years' follow-up, the mean major curve measured 25° (46% correction, p < 0.05). In 18 (82%) of 22 patients, the mean final Cobb angle measured ≤ 30° (range 15°-30°). Trunk shift was corrected by 1.5 cm (range 0.4-4.3 cm). The mean minor curve was reduced from 27° to 17° at final follow-up (35% correction, p < 0.05). For Lenke type 1 patterns, the mean 2D thoracic kyphosis was 24° preoperatively versus 27° at final follow-up (p < 0.05), and for Lenke type 5 curves, mean lumbar lordosis was 47° preoperatively versus 42° at final follow-up (p < 0.05). The mean preoperative Scoliosis Research Society-22 questionnaire score improved from 2.74 ± 0.3 at baseline to 4.31 ± 0.4 at 2 years after surgery (p < 0.0001). The mean preoperative self-image score and satisfaction scores improved from preoperative values, while other domain scores did not change significantly. Four patients (18%) underwent revision surgery because of nut loosening (n = 2), pedicle screw backup (n = 1), and ratchet malfunction (n = 1)., Conclusions: In AIS patients with a single flexible major curve up to 60°, the fusionless PDDC device achieved a satisfactory result as 82% had residual curves ≤ 30°. These findings suggest that the PDDC device may serve as an alternative to spinal fusion in select patients.

Study Design: Retrospective review of a prospectively collected multicenter database., Objective: The aim of this study was to investigate factors associated with low preoperative SRS pain scores., Summary of Background Data: The prevalence of preoperative pain in patients with adolescent idiopathic scoliosis (AIS) has become increasingly evident and is a primary concern for patients and families. Greater preoperative pain is associated with more postoperative pain; however, less is understood about what contributes to preoperative pain., Methods: A prospectively collected, multicenter database was queried for patients with AIS. Patients were divided into 2 cohorts based on preoperative SRS pain scores: ≤ 3 (Pain cohort), 4 to 5 (No Pain cohort). Univariate analysis was performed identifying which factors were associated with a low preoperative SRS score and used for a CART analysis., Results: Of 2585 patients total, 2141 (83%) patients had SRS pain scores of 4 to 5 (No Pain) and 444 (17%) had SRS pain scores ≤3 (Pain). Female sex, older age, greater % body mass index, larger lumbar curves, greater T5-12 kyphosis, and lower mental health scores were associated with greater preoperative pain. In multivariate CART analysis, lower mental health SRS scores (P = 0.04) and older age (P = 0.003) remained significant, with mental health scores having the greatest contribution. In subdividing the mental health component questions, anxiety-related questions appeared to have the greatest effect followed by mood/depression (SRS Question 13: OR 2.04; Q16: OR 1.35; Q7: OR 1.31; Q3: OR 1.20)., Conclusion: Anxiety and mood are potentially modifiable risk factors that have the greatest impact on pre- and postoperative pain. These results can be used to identify higher-risk patients and develop preoperative therapeutic protocols to improve postoperative outcomes., Level of Evidence: 3.

Brace treatment is the most common nonoperative treatment for the prevention of curve progression in adolescent idiopathic scoliosis. The success reported in level 1 and 2 clinical trials is approximately 75%. The aim of this review was to identify the main risk factors that significantly reduce success rate of brace treatment. A literature search using the MEDLINE and Embase databases was conducted. Studies were included if they identified specific risk factor(s) for curve progression. Studies that looked at nighttime braces, superiority of one type of brace over another, the effect of physical therapy on brace performance, cadaver or nonhuman studies were excluded. A total of 1,022 articles were identified of which 25 met all of the inclusion criteria. Seven risk factors were identified: Poor brace compliance (eight studies), lack of skeletal maturity (six studies), Cobb angle over a certain threshold (six studies), poor in-brace correction (three studies), vertebral rotation (four studies), osteopenia (two studies), and thoracic curve type (two studies). Three risk factors were highly repeated in the literature which identified specific subgroups of patients who have a much higher risk to fail brace treatment and to progress to fusion. This data demonstrates that 60% to 70% of the patients referred to bracing are Risser 0 and 30% to 70% of this group will not wear the brace enough to ensure treatment efficacy. Furthermore, Risser 0 patients who reach the accelerated growth phase with a curve ≥40° are at 70% to 100% risk of curve progression to the fusion surgical threshold despite proper brace wear. Skeletally immature patients with relatively large magnitude scoliosis who are noncompliant are at a higher risk of failing brace treatment., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Hypothesis: Body Image Disturbance Questionnaire-Scoliosis version (BIDQ-S) is a sensitive outcomes instrument to evaluate improvements in body image-related psychosocial effects with surgical correction., Design: Prospective observational study., Introduction: The BIDQ-S was previously validated (convergent validity, internal consistency) as a tool to assess body image-related distress and psychosocial impairment in adolescent idiopathic scoliosis (AIS). This study was conducted to evaluate responsiveness to change in the BIDQ-S associated with surgical treatment of AIS two years postoperatively to complete the validation of this questionnaire., Methods: Seventy-five consecutive operative AIS patients were enrolled and completed BIDQ-S and Scoliosis Research Society-22 (SRS-22) at preoperative and two-year postoperative visits. Demographic and radiographic data were collected. Preoperative and two-year postoperative BIDQ-S (1 = best, 5 = worst) and SRS-22 scores (1 = worst, 5 = best) were compared using paired t test. Correlations between BIDQ-S and SRS-22 scores were evaluated by linear regression., Results: Eighty-four percent of the subjects were females, with average age at surgery of 14.4 ± 1.6 years. The mean follow-up was 2.26 years (range 2.0-4.5). The major Cobb was corrected from 50.0° ± 7.2° to 14.2° ± 5.8° (Δ = 71.3% ± 12.1%; p < .0001). There was a significant improvement in BIDQ-S scores after surgery (1.64 ± 0.51 to 1.21 ± 0.38, p < .0001). BIDQ-S improvements were correlated with change in SRS self-image (p = .0055), activity (p = .0057), mental (p = .0018), and overall mean (p = .0007) domains. Preoperative, two-year postoperative, and Δ BIDQ-S score were not associated with major Cobb magnitude, truncal rotation, or Lenke curve type. Patients who reached SRS-22r minimal clinically important difference (MCID) in activity and self-image domains had worse preoperative BIDQ scores than those who did not reach MCID (activity 1.91 vs. 1.54 [1 = best, 5 = worst], p = .0099; self-image 2.08 vs. 1.51, p < .0001). Greater improvement in BIDQ-S was noted in patients who reached MCID in SRS-22 self-image than those who did not (Δ = 0.77 vs. 0.38, p = .0052)., Conclusion: BIDQ-S is responsive to surgical correction of AIS. The BIDQ-S is a valuable clinical outcome tool to assess the psychosocial effects of scoliosis in adolescents augmenting existing outcome instruments., (Copyright © 2019 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background Context: The minimal clinically important difference (MCID) is the smallest change in an outcomes instrument deemed relevant to a patient. MCID values proposed in spine research are limited by poor discriminative abilities to accurately classify patients as "improved" or "not improved." Furthermore, the MCID should not compare relative effectiveness between two groups of patients, though it is frequently used for this. The minimum detectable measurement difference (MDMD) is an alternative to the MCID in outcomes research. The MDMD must be greater than the MCID for the latter to be of value and the MDMD can compare change between groups., Purpose: The purpose of this study was to determine the MDMD for the Scoliosis Research Society-22r (SRS-22r) in adolescent idiopathic scoliosis (AIS) patients treated with surgery., Study Design: Retrospective cohort study from multi-center registry., Patient Sample: Patients treated surgically for AIS., Outcome Measures: Self-reported SRS-22r., Methods: An observational cohort of surgically treated AIS patients was queried for patients with complete baseline, 1-year, and 2-year SRS-22r data. The MDMD was calculated for SRS-22r domain and subscores. Effect size (ES) and standardized response mean were calculated to measure responsiveness of the SRS-22r to change. MDMD values were compared with MCID values. Research grants were received from DePuy Synthes Spine, EOS imaging, K2M, Medtronic, NuVasive, and Zimmer Biomet to Setting Scoliosis Straight Foundation., Results: One thousand two hundred and eighty-one AIS patients (1,034 female, 247 male, mean age 14.6 years) were analyzed. MDMD values were between 0.23 and 0.31. SRS-Pain MDMD was 0.3, greater than the MCID of 0.2. SRS-Activity MDMD was 0.24, greater than the MCID of 0.08. SRS-self-image MDMD was 0.3, less than the MCID of 0.98. Sixty-four percent of those with baseline SRS-self-image>4.0 improved MDMD or more, whereas only 14% improved beyond the MCID. ES and standardized response mean were highest for subscore and self-image., Conclusions: The MDMD can compare the relevance of change in SRS-22r scores between groups of AIS patients. SRS-pain and SRS-activity MDMD values are greater than the MCID and should serve as the threshold for clinically relevant improvement. MDMD may help evaluate change in patients with baseline self-image>4.0., (Copyright © 2019 Elsevier Inc. All rights reserved.)

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: At academic medical centers, residents and fellows play an integral role as surgical first assistants in spinal deformity surgery. However, limited data exist on whether the experience level of the surgical assistant affects outcomes., Methods: We conducted a multicenter, multisurgeon study comparing perioperative and postoperative outcomes after adolescent idiopathic scoliosis (AIS) surgery for the same 11 surgeons who performed cases that were assisted by residents compared with cases that were assisted by fellows. Blood loss, operative time, duration of hospitalization, complication rates, Scoliosis Research Society (SRS)-22 questionnaire scores, and radiographic outcomes were compared between the 2 groups., Results: We evaluated outcomes for 347 surgical procedures; 118 cases were assisted by residents and 229 were assisted by fellows. Preoperative radiographic and demographic parameters were not different between the groups. The resident group had significantly more estimated blood loss than the fellow group (939 compared with 762 mL, p = 0.02). Otherwise, the perioperative characteristics were similar between the groups, including the volume of the autologous blood recovery system product that was transfused, the operative time, and the occurrence of intraoperative neuromonitoring changes. Postoperatively, the percentage correction of the Cobb angle, the number of levels that had been fused, the number of days until the discharge criteria had been met, and the rate of major complications were similar between the groups. At the 2-year follow-up, the overall and subdomain SRS-22 questionnaire scores were not different between the groups, except that patients in the resident-assisted group had slightly worse pain scores than those in the fellow-assisted group (4.3 compared with 4.5, p = 0.01)., Conclusions: The first assistant's level of training did not affect clinical or radiographic outcomes following AIS surgery., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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: Biomechanical test., Objective: To summarize the preclinical tests performed to assess the durability of a novel fusionless dynamic device for the treatment of adolescent idiopathic scoliosis (AIS)., Summary of Background Data: The minimal invasive deformity correction (MID-C) system is a distractible posterior dynamic deformity correction device designed to reduce scoliosis for AIS patients, to maintain curve correction, and to preserve spinal motion. To overcome the challenges of wear and fatigue of this procedure, the system has two unique features: polyaxial joints at the rod-screw interface and a ceramic coating of the moving parts., Methods: Five biomechanical tests were performed: Static compression to failure, fatigue loading per ASTM F 1717 with 5.5-mm screws for 10 million cycles (MC) at 5 Hz, wear assessment, wear test of the polyaxial joint under 100 N load for 10 MC, and wear particle implantation in rabbits., Results: The system failed through buckling of the rod with loads over 3000 N (400% of human body weight). Dynamically, the system maintained 700 N for 10 MC with 5.5 mm screws. The maximum total steady-state wear rate was 0.074 mg/MC (0.03 per polyaxial joint and 0.014 mg/MC for the ratchet mechanism). Histologic evaluation of the particle injection sites indicated no difference in the local tissue response between the control and test articles. At 3 and 6 months postinjection, there were neither adverse local effects nor systemic effects observed., Conclusions: The unique design features of the MID-C system, based on polyaxial joints and ceramic coating, resulted in favorable static, fatigue, and wear resistance properties. Wear properties were superior to those published for artificial spinal discs. Long-term outcomes from clinical use will be required to correlate these bench tests to the in vivo reality of clinical use., Level of Evidence: Level V., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Cost-utility analysis OBJECTIVE.: To compare the cost utility of operative versus nonoperative treatment of adolescent idiopathic scoliosis (AIS) and identity factors that influence cost-utility estimates., Summary of Background Data: AIS affects 1% to 3% of children aged 10 to 16 years. When the major coronal curve reaches 50°, operative treatment may be considered. The cost utility of operative treatment of AIS is unknown., Methods: A decision-analysis model comparing operative versus nonoperative treatment was developed for a hypothetical 15-year-old skeletally mature girl with a 55° right thoracic (Lenke 1) curve. The AIS literature was reviewed to estimate the probability, health utility, and quality-adjusted life years (QALYs) for each event. For the conservative model, we assumed that operative treatment did not result directly in any QALYs gained, and the health utility in AIS patients was the same as the age-matched US population mean. Costs were inflation-adjusted at 3.22% per year to 2015 US dollars. Costs and benefits were discounted at 3%. Probabilistic sensitivity analysis was performed using mixed first-order and second-order Monte Carlo simulations. Incremental cost utility ratio (ICUR) and incremental net monetary benefit were calculated. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates., Results: Operative treatment was favored in 98.5% of simulations, with a median ICUR of $20,600/QALY (95% confidence interval, $20,500-$21,900) below the societal willingness-to-pay threshold (WTPT) of $50,000/QALY. The median incremental net monetary benefit associated with operative treatment was $15,100 (95% confidence interval, $14,800-$15,700). Operative treatment produced net monetary benefit across various WTPTs. Factors that most affected the ICUR were net costs associated with uncomplicated operative treatment, undergoing surgery during adulthood, and development of pulmonary complications., Conclusion: Cost-utility analysis suggests that operative treatment of AIS is favored over nonoperative treatment and falls below the $50,000/QALY WTPT for patients with Lenke 1 curves., Level of Evidence: 2.

Study Design: Observational cohort study of prospective database registry., Objective: To determine the incidence of neurological complications in AIS patients undergoing surgical treatment with PO., Summary of Background Data: Despite the widespread use of Ponte Osteotomies (PO) in adolescent idiopathic scoliosis (AIS) correction, outcomes and complications in patients treated with this technique have not been well characterized., Methods: A multicenter prospective registry of patients undergoing surgical correction of AIS was queried at 2-year follow-up for patient demographics, surgical data, deformity characteristics, and peri-operative complications. A neurological complication was defined as perioperative nerve root or spinal cord injury as identified by the surgeon. Patients were divided into those who underwent peri-apical PO and those without, and further stratified by Lenke curve classification into 3 groups (I-types 1 and 2, II-types 3, 4, 6, and III-type 5). Patients with- and without neurological complications were compared with respect to baseline demographics, surgical variables, curve types, fusion construct types (screws vs. hybrid), curve magnitude (coronal and sagittal Cobb), apical vertebral translation, and coronal-deformity angular ratios (C-DAR)., Results: Of 2210 patients included in the study, 1611 underwent PO. Peri-operative neurological complications occurred in 7 patients, with 6 in the PO group (0.37%) and 1 in non-PO group (0.17%) though this was not a statistically significant risk factor for peri-operative neurological injury (P = 0.45). Neuromonitoring alerts were recorded in 168 patients (7.6%: 9.3% PO group; 4.2% no-PO group (P < 0.001)). Multivariate logistic regression analysis found PO and curve magnitude to be independent risk factors for intraoperative neuromonitoring alerts (P < 0.01)., Conclusion: PO and curve magnitude were independent risk factors for intraoperative neuromonitoring alerts in surgical AIS correction. The effect of Ponte osteotomy on neurological complications remains unknown due to the low incidence of these complications., Level of Evidence: 3.

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.)