Influence of curve morphology and location on the efficacy of rigid conservative treatment in patients with adolescent idiopathic scoliosis

Aims The aim of the present study was to answer the question whether curve morphology and location have an influence on rigid conservative treatment in patients with adolescent idiopathic scoliosis (AIS). Methods We retrospectively analyzed AIS in 127 patients with single and double curves who had been treated with a Chêneau brace and physiotherapeutic specific exercises (B-PSE). The inclusion criteria were the presence of structural major curves ≥ 20° and < 50° (Risser stage 0 to 2) at the time when B-PSE was initiated. The patients were divided into two groups according to the outcome of treatment: failure (curve progression to ≥ 45° or surgery) and success (curve progression < 45° and no surgery). The main curve type (MCT), curve magnitude, and length (overall, above and below the apex), apical rotation, initial curve correction, flexibility, and derotation by the brace were compared between the two groups. Results In univariate analysis treatment failure depended significantly on: 1) MCT (p = 0.008); 2) the apical rotation of the major curve before (p = 0.007) and during brace treatment (p < 0.001); 3) the initial and in-brace Cobb angles of the major (p = 0.001 and p < 0.001, respectively) and minor curves (p = 0.015 and p = 0.002); 4) major curve flexibility (p = 0.005) and the in-brace curve correction rates (major p = 0.008, minor p = 0.034); and 5) the length of the major curve (LoC) above (p < 0.001) and below (p = 0.002) the apex. Furthermore, MCT (p = 0.043, p = 0.129, and p = 0.017 in MCT comparisons), LoC (upper length p = 0.003, lower length p = 0.005), and in-brace Cobb angles (major p = 0.002, minor p = 0.027) were significant in binary logistic regression analysis. Conclusion Curve size, location, and morphology were found to influence the outcome of rigid conservative treatment of AIS. These findings may improve future brace design and patient selection for conservative treatment. Cite this article: Bone Joint J 2021;103-B(2):373–381.

Download Full-text

Higher pedicle screw density does not improve curve correction in Lenke 2 adolescent idiopathic scoliosis

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02415-4 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Timothy J. Skalak ◽

Joel Gagnier ◽

Michelle S. Caird ◽

Frances A. Farley ◽

Ying Li

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Thoracic Kyphosis ◽

Curve Correction ◽

Major Curve ◽

Curve Magnitude ◽

Screw Density ◽

Implant Density ◽

Lenke 2

Abstract Purpose Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS. Methods We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow-up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis. Results Thirty patients (21 females, 9 males) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11–17 years), and median follow-up was 2.8 years (IQR 2.1–4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis. Conclusions Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude. Level of evidence Level III, retrospective observational

Download Full-text

“Higher Pedicle Screw Density Does Not Result in Improved Curve Correction in Lenke 2 Adolescent Idiopathic Scoliosis”

10.21203/rs.3.rs-262745/v1 ◽

2021 ◽

Author(s):

Timothy Skalak ◽

Joel Gagnier ◽

Michelle S. Caird ◽

Frances A. Farley ◽

Ying Li

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Thoracic Kyphosis ◽

Curve Correction ◽

Major Curve ◽

Curve Magnitude ◽

Screw Density ◽

Implant Density ◽

Lenke 2

Abstract Purpose: Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS. Methods: We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis. Results: Thirty patients (21 Female, 9 male) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11-17 years) and median follow-up was 2.8 years (IQR 2.1-4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis.Conclusions: Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude.Level of Evidence: Level III Retrospective Observational

Download Full-text

What happens to the unfused upper thoracic curve after posterior spinal fusion for adolescent idiopathic scoliosis?

Journal of Neurosurgery Pediatrics ◽

10.3171/2020.10.peds20671 ◽

2021 ◽

pp. 1-7

Author(s):

M. Omar Iqbal ◽

Amer F. Samdani ◽

Joshua M. Pahys ◽

Peter O. Newton ◽

Suken A. Shah ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Univariate Analysis ◽

Posterior Spinal Fusion ◽

Research Society ◽

Curve Correction ◽

Scoliosis Research Society ◽

Lenke Classification ◽

Upper Instrumented Vertebra ◽

Upper Thoracic

OBJECTIVE Spontaneous lumbar curve correction after selective thoracic fusion in surgery for adolescent idiopathic scoliosis (AIS) is well described. However, only a few articles have described the course of the uninstrumented upper thoracic (UT) curve after fusion, and the majority involve a hybrid construct. In this study, the authors sought to determine the outcomes and associated factors of uninstrumented UT curves in patients with AIS. METHODS The authors retrospectively reviewed a prospectively collected multicenter AIS registry for all consecutive patients with Lenke type 1–4 curves with a 2-year minimum follow-up. UT curves were considered uninstrumented if the upper instrumented vertebra (UIV) did not extend above 1 level from the lower end vertebra of the UT curve. The authors defined progression as > 5°, and divided patients into two cohorts: those with improvement in the UT curve (IMP) and those without improvement in the UT curve (NO IMP). Radiographic, demographic, and Scoliosis Research Society (SRS)–22 survey outcome measures were compared using univariate analysis, and significant factors were compared using a multivariate regression model. RESULTS The study included 450 patients (370 females and 80 males). The UT curve self-corrected in 86% of patients (n = 385), there was no change in 14% (n = 65), and no patients worsened. Preoperatively, patients were similar with respect to Lenke classification (p = 0.44), age (p = 0.31), sex (p = 0.85), and Risser score (p = 0.14). The UT curves in the IMP group self-corrected from 24.7° ± 6.5° to 12.6° ± 5.9°, whereas in the NO IMP group UT curves remained the same, from 20.3° ± 5.8° to 18.5° ± 5.7°. In a multivariate analysis, preoperative main thoracic (MT) curve size (p = 0.004) and MT curve correction (p = 0.001) remained significant predictors of UT curve improvement. Greater correction of the MT curve and larger initial MT curve size were associated with greater likelihood of UT curve improvement. CONCLUSIONS Spontaneous UT curve correction occurred in the majority (86%) of unfused UT curves after MT curve correction in Lenke 1–4 curve types. The magnitude of preoperative MT curve size and postoperative MT curve correction were independent predictors of spontaneous UT curve correction.

Download Full-text

Supine flexibility predicts curve progression for patients with adolescent idiopathic scoliosis undergoing underarm bracing

The Bone & Joint Journal ◽

10.1302/0301-620x.102b2.bjj-2019-0916.r1 ◽

2020 ◽

Vol 102-B (2) ◽

pp. 254-260 ◽

Cited By ~ 4

Author(s):

Jason P. Y. Cheung ◽

Prudence W. H. Cheung

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Regression Model ◽

Cobb Angle ◽

Characteristic Curve ◽

Absolute Error ◽

Curve Progression ◽

Curve Magnitude ◽

Spine Radiograph ◽

Whole Spine

Aims The aim of this study was to assess whether supine flexibility predicts the likelihood of curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment. Methods This was a retrospective analysis of patients with AIS prescribed with an underarm brace between September 2008 to April 2013 and followed up until 18 years of age or required surgery. Patients with structural proximal curves that preclude underarm bracing, those who were lost to follow-up, and those who had poor compliance to bracing (<16 hours a day) were excluded. The major curve Cobb angle, curve type, and location were measured on the pre-brace standing posteroanterior (PA) radiograph, supine whole spine radiograph, initial in-brace standing PA radiograph, and the post-brace weaning standing PA radiograph. Validation of the previous in-brace Cobb angle regression model was performed. The outcome of curve progression post-bracing was tested using a logistic regression model. The supine flexibility cut-off for curve progression was analyzed with receiver operating characteristic curve. Results A total of 586 patients with mean age of 12.6 years (SD 1.2) remained for analysis after exclusion. The baseline Cobb angle was similar for thoracic major curves (31.6° (SD 3.8°)) and lumbar major curves (30.3° (SD 3.7°)). Curve progression was more common in the thoracic curves than lumbar curves with mean final Cobb angles of 40.5° (SD 12.5°) and 31.8° (SD 9.8°) respectively. This dataset matched the prediction model for in-brace Cobb angle with less mean absolute error in thoracic curves (0.61) as compared to lumbar curves (1.04). Reduced age and Risser stage, thoracic curves, increased pre-brace Cobb angle, and reduced correction and flexibility rates predicted increased likelihood of curve progression. Flexibility rate of more than 28% has likelihood of preventing curve progression with bracing. Conclusion Supine radiographs provide satisfactory prediction for in-brace correction and post-bracing curve magnitude. The flexibility of the curve is a guide to determine the likelihood for brace success. Cite this article: Bone Joint J 2020;102-B(2):254–260.

Download Full-text

Efficacy of Routine Intraoperative Cranio-Femoral Traction in Surgical Treatment of Adolescent Idiopathic Scoliosis Curves Measuring Between 50° and 90°

Global Spine Journal ◽

10.1177/21925682211052969 ◽

2021 ◽

pp. 219256822110529

Author(s):

Jacob R. Carl ◽

Gurpal Pannu ◽

Evan Cherng-Yeh Chua ◽

Adam Bacon ◽

Blythe Durbin-Johnson ◽

...

Keyword(s):

Surgical Treatment ◽

Adolescent Idiopathic Scoliosis ◽

Blood Loss ◽

Idiopathic Scoliosis ◽

Revision Surgery ◽

Operative Time ◽

Curve Correction ◽

Major Curve ◽

Estimated Blood Loss ◽

Retrospective Comparative Study

Study Design Retrospective Comparative Study, Level III. Objective In patients with scoliosis >90°, cranio-femoral traction (CFT) has been shown to obtain comparable curve correction with decreased operative time and blood loss. Routine intraoperative CFT use in the treatment of AIS <90° has not been established definitively. This study investigates the effectiveness of intraoperative CFT in the treatment of AIS between 50° and 90°, comparing the magnitude of curve correction, blood loss, operative time, and traction-related complications with and without CFT. Methods 73 patients with curves less than 90° were identified, 36 without and 37 with cranio-femoral traction. Neuromuscular scoliosis and revision surgery were excluded. Age, preoperative Cobb angles, bending angles, and curve types were recorded. Surgical characteristics were analyzed including number of levels fused, estimated blood loss, operative time, major curve correction (%), and degree of postoperative kyphosis. Results Patients with traction had significantly higher preoperative major curves but no difference in age or flexibility. Lenke 1 curves had significantly shorter operative time and improvement in curve correction with traction. Among subjects with 5 to 8 levels fused, subjects with traction had significantly less EBL. Operative time was significantly shorter for subjects with 5-8 levels and 9-11 levels fused. Curves measuring 50°-75° showed improved correction with traction. Conclusion Intraoperative traction resulted in shorter intraoperative time and greater correction of major curves during surgical treatment of adolescent idiopathic scoliosis less than 90°. Strong considerations should be given to use of intraoperative CFT for moderate AIS.

Download Full-text

APSS-ASJ Best Clinical Research Award: Predictability of Curve Progression in Adolescent Idiopathic Scoliosis Using the Distal Radius and Ulna Classification

Asian Spine Journal ◽

10.4184/asj.2018.12.2.202 ◽

2018 ◽

Vol 12 (2) ◽

pp. 202-213 ◽

Cited By ~ 10

Author(s):

Jason Pui Yin Cheung ◽

Prudence Wing Hang Cheung ◽

Dino Samartzis ◽

Keith Dip-Kei Luk

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Distal Radius ◽

Skeletal Maturity ◽

Curve Progression ◽

Close Monitoring ◽

Skeletally Immature ◽

Increased Risk ◽

Curve Magnitude

<sec><title>Study Design</title>Prospective study.</sec><sec><title>Purpose</title>To determine the risk of clinically significant curve progression in adolescent idiopathic scoliosis (AIS) based on the initial Cobb angle and to test the utility of the distal radius and ulna (DRU) classification in predicting these outcomes.</sec><sec><title>Overview of Literature</title>Determining the remaining growth potential in AIS patients is necessary for predicting prognosis and initiating treatment. Limiting the maturity Cobb angle to <40° and <50° reduces the risk of adulthood progression and need for surgery, respectively. The risk of curve progression is the greatest with skeletally immature patients and thus warrants close monitoring or early intervention. Many parameters exist for measuring the skeletal maturity status in AIS patients, but the DRU classification has been shown to be superior in predicting peak growth and growth cessation. However, its predictive capabilities for curve progression are unknown.</sec><sec><title>Methods</title>Totally, 513 AIS patients who presented with Risser 0–3 were followed until either skeletal maturity or the need for surgery, with a minimum 2-year follow-up period. Outcomes of 40° and 50° were used for probability analysis based on the cut-offs of adulthood progression risk and surgical threshold, respectively.</sec><sec><title>Results</title>At the R6/U5 grade, most curves (probability of ≥48.1%–55.5%) beyond a Cobb angle of 25° progressed to the 40° threshold. For curves of ≥35°, there was a high risk of unfavorable outcomes, regardless of skeletal maturity. Most patients with the R9 grade did not progress, regardless of the initial curve magnitude (probability of 0% to reach the 50° threshold for an initial Cobb angle of ≥35°).</sec><sec><title>Conclusions</title>This large-scale study illustrates the utility of the DRU classification for predicting curve progression and how it may effectively guide the timing of surgery. Bracing may be indicated for skeletally immature patients at an initial Cobb angle of 25°, and those with a scoliosis ≥35° are at an increased risk of an unfavorable outcome, despite being near skeletal maturity.</sec>

Download Full-text

Genetic variant of MIR4300HG is associated with progression of adolescent idiopathic scoliosis in a Chinese population

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02455-w ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Yuwen Wang ◽

Zhicheng Dai ◽

Zhichong Wu ◽

Zhenhua Feng ◽

Zhen Liu ◽

...

Keyword(s):

Gene Expression ◽

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Target Gene ◽

Pearson Correlation ◽

Curve Progression ◽

Control Analysis ◽

Curve Magnitude ◽

Intergroup Comparison ◽

Curve Severity

Abstract Background A recent genome-wide association study identified a susceptible locus in MIR4300HG gene that was associated with curve progression of adolescent idiopathic scoliosis (AIS) in the Japanese population. However, the association between the gene and curve progression in other populations remains unclear. Methods A cohort of 1952 AIS patients and 2495 healthy controls were included in the case-control analysis. In the case-only analysis, 747 patients were assigned to the progression group and 520 patients were assigned to the non-progression group, respectively. Rs35333564 was genotyped for all the subjects. Paraspinal muscles of 76 patients were collected for the analysis of gene expression. Chi-square test and ANOVA test were used for the intergroup comparison. Pearson correlation analysis was performed to investigate the relationship between the gene expression and curve magnitude. Results Variant rs35333564 was significantly associated with the curve severity of AIS (p = 0.025), but not the development of AIS (p = 0.418). Genotype GG was indicated by remarkably lower expression of MIR4300 (p = 0.020) which was significantly correlated with curve magnitude (p = 0.010). As a predicted target gene of MIR4300, the expression of CRTC1 was negatively correlated with MIR4300 expression (p = 0.012, r = −0.287) and positively correlated with curve severity (p = 0.025, r = 0.257). Conclusions The association between rs35333564 and curve progression was successfully replicated in a Chinese AIS population. CRTC1 may be the target gene of MIR4300 that plays a role in the curve progression of AIS.

Download Full-text

Prediction of Final Body Height for Female Patients With Adolescent Idiopathic Scoliosis

Global Spine Journal ◽

10.1177/2192568220941450 ◽

2020 ◽

pp. 219256822094145

Author(s):

Prudence Wing Hang Cheung ◽

Abhishek Mannem ◽

Jason Pui Yin Cheung

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Body Height ◽

Initial Presentation ◽

Major Curve ◽

Female Patients ◽

Arm Span ◽

Curve Magnitude ◽

Height Increase

Study Design: Retrospective cohort study. Objectives: To explore the possibility of predicting final body height at maturity based on associating parameters at the time of diagnosing adolescent idiopathic scoliosis (AIS), while examining the effect of curve magnitude and deterioration. Methods: A total of 284 female patients with AIS (mean age 12.2 ± 1.1 years, 52.5% premenarchal) were followed till skeletal maturity, indicated by ≥Risser stage 4, static body height and arm span over the past 6 months, and postmenarche 2 years. Standing body height, arm span, menarchal status, Risser staging, distal radius and ulna (DRU) classification, Sanders staging (SS), Cobb angles (major and minor curves), and Lenke curve types at initial presentation were examined. Patients with/without curve deterioration were compared. Multiple linear regression was used for predicting final body height (cm), and remaining height increase (%). Results: Baseline body height was 152.1 ± 7.1 cm and major curve Cobb angle was 27.1° ± 7.4°, whereas at maturity they were 159.5 ± 5.4 cm and 32.5° ± 9.3°, respectively. For patients presented at Risser stage 0 or 1, radius grade (R) 6, ulnar grade (U) 5, or SS3, those with curve deterioration exhibited greater height increase potential at initial presentation ( P < .05) than those without deterioration. No intergroup difference was found for patients presented at ≥Risser 2, R7, U6, SS4. Predictive baseline parameters were age, body height, Cobb angle (major curve), curve type, and DRU grades. Prediction models of final body height ( R 2 = 0.735, P < .001) and remaining height increase ( R 2 = 0.742, P < .001) were established. Conclusions: Final body height prediction model was derived for female patients with AIS, with baseline body height and ulnar grading having larger impacts than other parameters.

Download Full-text

Surgical management of moderate adolescent idiopathic scoliosis with a fusionless posterior dynamic deformity correction device: interim results with bridging 5–6 disc levels at 2 or more years of follow-up

Journal of Neurosurgery Spine ◽

10.3171/2019.11.spine19827 ◽

2020 ◽

Vol 32 (5) ◽

pp. 748-754 ◽

Cited By ~ 1

Author(s):

Yizhar Floman ◽

Ron El-Hawary ◽

Michael A. Millgram ◽

Baron S. Lonner ◽

Randal R. Betz

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Deformity Correction ◽

Successful Outcome ◽

Inclusion Criteria ◽

Major Curve ◽

Curve Magnitude ◽

The Mean

OBJECTIVEA 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.METHODSInclusion 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.RESULTSTwenty-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).CONCLUSIONSIn 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.

Download Full-text

Should L3 be selected as the lowest instrumented vertebra in patients with Lenke type 5C adolescent idiopathic scoliosis whose lowest end vertebra is L4?

Journal of Neurosurgery Spine ◽

10.3171/2020.11.spine201807 ◽

2021 ◽

pp. 1-10

Author(s):

Tomohiro Banno ◽

Yu Yamato ◽

Hiroki Oba ◽

Tetsuro Ohba ◽

Tomohiko Hasegawa ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Curve Progression ◽

Global Alignment ◽

Fusion Surgery ◽

Radiographic Outcomes ◽

Lowest Instrumented Vertebra ◽

Upper Instrumented Vertebra ◽

Coronal Decompensation

OBJECTIVE L3 is most often selected as the lowest instrumented vertebra (LIV) to conserve mobile segments in fusion surgery; however, in cases with the lowest end vertebra (LEV) at L4, LIV selection as L3 could have a potential risk of correction loss and coronal decompensation. This study aimed to compare the clinical and radiographic outcomes depending on the LEV in adolescent idiopathic scoliosis (AIS) patients with Lenke type 5C curves. METHODS Data from 49 AIS patients with Lenke type 5C curves who underwent selective thoracolumbar/lumbar (TL/L) fusion to L3 as the LIV were retrospectively analyzed. The patients were classified according to their LEVs into L3 and L4 groups. In the L4 group, subanalysis was performed according to the upper instrumented vertebra (UIV) level toward the upper end vertebra (UEV and 1 level above the UEV [UEV+1] subgroups). Radiographic parameters and clinical outcomes were compared between these groups. RESULTS Among 49 patients, 32 and 17 were in the L3 and L4 groups, respectively. The L4 group showed a lower TL/L curve correction rate and a higher subjacent disc angle postoperatively than the L3 group. Although no intergroup difference was observed in coronal balance (CB), the L4 group showed a significantly higher main thoracic (MT) and TL/L curve progression during the postoperative follow-up period than the L3 group. In the L4 group, the UEV+1 subgroup showed a higher absolute value of CB at 2 years than the UEV subgroup. CONCLUSIONS In Lenke type 5C AIS patients with posterior selective TL/L fusion to L3 as the LIV, patients with their LEVs at L4 showed postoperative MT and TL/L curve progression; however, no significant differences were observed in global alignment and clinical outcome.

Download Full-text