Lenke Type Research Articles

Comparative analysis of modified posterior mini-open surgery versus standard open posterior approach for adolescent idiopathic scoliosis correction: a prospective study.

Adolescent idiopathic scoliosis (AIS) surgery aims to achieve optimal deformity correction while minimizing complications. The standard open posterior approach (OS) is effective but associated with significant soft tissue disruption and prolonged recovery. The modified mini-open surgery (MS) technique offers a less invasive alternative, potentially reducing surgical morbidity while maintaining comparable correction. In this prospective comparative study, 60 Lenke type 1 AIS patients with single thoracic curves were randomized to MS (n = 30) or OS (n = 30) groups. The MS technique utilized three midline incisions, a muscle-splitting approach, and selective arthrodesis at instrumented levels. Outcomes included deformity correction, intraoperative blood loss, hospital stay, postoperative pain (VAS), scar satisfaction, fusion rates, and complications at 2 years. Both groups achieved comparable correction with no loss at 2 years (MS: 79.7% ± 8.0%; OS: 85.0% ± 7.4%; p > 0.05). The MS group had reduced intraoperative blood loss (383.3 ± 82.9mL vs. 720.2 ± 74.3mL; p = 0.019), shorter hospital stays (6.2 ± 0.3 vs. 7.4 ± 1.2days; p = 0.044), and lower VAS scores at discharge (2.9 ± 1.8 vs. 3.9 ± 1.4; p = 0.02) and 2 years (1.5 ± 0.5 vs. 2.0 ± 0.7; p = 0.03). Scar satisfaction was higher in the MS group (4.5 ± 0.3 vs. 2.8 ± 0.6; p = 0.02). No pseudoarthrosis or complications occurred in either group. The MS approach offers comparable correction to OS with reduced morbidity and superior cosmesis.

Deep learning based decision-making and outcome prediction for adolescent idiopathic scoliosis patients with posterior surgery

With the emergence of numerous classifications, surgical treatment for adolescent idiopathic scoliosis (AIS) can be guided more effectively. However, surgical decision-making and optimal strategies still lack standardization and personalized customization. Our study aims to devise proper deep learning (DL) models that incorporate key factors influencing surgical outcomes on the coronal plane in AIS patients to facilitate surgical decision-making and predict surgical results for AIS patients. A total of 425 AIS patients who underwent posterior spinal fixation were collected. Variables such as age, gender, preoperative and final follow-up horizontal and vertical coordinate vectors, and screw positioning data were preprocessed by parameterizing image data and transforming various data types into a unified, continuous high-dimensional feature space. Four deep learning models were designed, including Multi-Layer Perceptron model, Encoder-Decoder model, CNN-LSTM Attention model and Deep FM model. For the implementation of deep learning, 70% of the data was adopted for training and 30% for evaluation. The mean square error (MSE), mean absolute error (MAE) and curve fitting between the predicted and corresponding real postoperative spinal coordinates of the test set were adopted to validate and compare the efficacy of the DL models. A total of 425 patients with an average age of 14.60 ± 2.08 years, including 77 males and 348 females, were enrolled in this study. The Lenke type 1 and 5 AIS patients accounted for the majority of the included patients. The results showed that the Multi-Layer Perceptron model achieved the best performance among the four DL models, with a mean square error of 2.77 × 10–5 and an average absolute error of 0.00350 on the validation set. Moreover, the results predicted by the Multi-Layer Perceptron model closely matched the actual coordinate positions on the original postoperative images of patients with Lenke type 1 and AIS patients. Deep learning models can provide alternative and effective decision-making support for AIS patients undergoing surgery. Regarding the learning curve and data volume, the optimal DL models should be adjusted and refined to meet future demands.

Which Lenke type curve is most appropriate for vertebral body tethering in adolescent idiopathic scoliosis?

Clinical trials have studied the effects of curve magnitude and flexibility, age, and skeletal immaturity on the outcomes of VBT. No studies have assessed the effect of Lenke curve type on the outcomes of VBT. This study compares outcomes in patients who underwent VBT with Lenke type 1, 3, 5, and 6 curves. Single center retrospective review of patients undergoing mini-open thoracoscopic-assisted two row vertebral body tethering (2RVBT) for the correction of AIS with a minimum 2-year follow-up were included. Patients were grouped by Lenke type, which yielded 4 groups; types 1, 3, 5, or 6. Analysis included preoperative demographic parameters, as well as radiographic and clinical outcome measures. 156 2RVBT (Lenke 1, N = 61; Lenke 3, N = 35; Lenke 5, N = 37; Lenke 6, N = 23) patients met inclusion criteria. The mean preoperative apex Cobb angle in the Lenke type 1, 3, 5, and 6 groups were 50.2 ± 9.1, 50.5 ± 10.1, 45.0 ± 8.6, and 49.0 ± 10.8, respectively. This corrected to 21.2 ± 10.2, 19.2 ± 8.5, 13.6 ± 7.2, 18.5 ± 8.3 in Lenke type 1, 3, 5, and 6 groups, respectively, demonstrating that Lenke type 5 saw greatest correction following 2RVBT. With regards to revision recommendation following tether breakage, Lenke type 3 curves were most frequently indicated for fusion, whereas Lenke type 1 curves were most frequently not indicated for revision surgery. Lenke type 5 curves are the most amenable to correction via 2RVBT, as evident by their lower post-operative apex Cobb angles and lowest rate of recommendation for revision to posterior spinal fusion.

The aortic-vertebral distance is more associated with axial plane deformities than coronal and sagittal deformities in idiopathic scoliosis patients of Lenke types I and II.

Although idiopathic scoliosis is a common three-dimensional deformity, there is a lack of studies evaluating the associations between the aortic-vertebral distance (AVD) and spinal deformities in all planes. The study therefore aimed to evaluate how the coronal and sagittal curvature, vertebral rotation and aortic-vertebral angle (AVA) affect the AVD in idiopathic scoliosis. The AVD, AVA, vertebral rotation and curve angles were measured on preoperative magnetic resonance imaging and radiographs in 46 patients who underwent posterior spinal fusion with pedicle screw instrumentation for idiopathic scoliosis Lenke types 1 and 2. Associations between variables were examined using correlation and multivariable regression analyses. A significant weak to strong correlation was found between the AVD and AVA, and the AVD and vertebral rotation (r = 0.315 to 0.712) within the thoracic curve. The sagittal kyphosis and coronal Cobb angles showed weak correlations with the AVD (r = -0.311 to 0.338). The regression model for the apical vertebral level, which included the four variables, explained 40% (R²=0.40) of the variation in AVD. AVA and vertebral rotation were significantly associated with AVD (p < 0.01 for each), together accounting for 34% (R²=0.34) of the variation. The shortest distance from the aortic wall to the vertebral body wall is primarily influenced by vertebral rotation and the AVA within the thoracic curve. Thus, these factors need to be taken into consideration when planning pedicle screw placement especially in freehand techniques.

AIS patients have improved total SRS-22r self-image and satisfaction scores relative to pre-op at 10-year follow-up regardless of Lenke type.

Few studies have investigated quality-of-life (QoL)-related outcome measures in adolescent idiopathic scoliosis (AIS) patients over long-term follow-up. We investigated whether patients with any given Lenke type improved relative to other types and whether selective fusions resulted in better QoL-related outcome measures. We utilized the Harms Study Group database to select patients with AIS who underwent posterior spinal fusion (PSF) with Scoliosis Research Society questionnaire-22 revised (SRS-22r) scores at minimum 10-year follow-up. Characteristics and SRS-22r were quantified by Lenke type and compared using ANOVA and Tukey post hoc tests. Multivariate analyses were conducted to identify the predictive value of Lenke types on QoL-related outcomes. Sub-group analysis split cohorts into those who underwent selective vs. non-selective fusion(s). 110 patients were available at minimum 10-year follow-up. Types 3, 4, and 6 curves generally demonstrated lower SRS-22r scores both preoperatively and at long-term follow-up. Independent of Lenke type, total SRS-22r, along with self-image and satisfaction, showed consistent improvement relative to pre-op at 10-year follow-up, whereas pain, mental health, and general function showed a slight worsening. Sub-group analyses revealed no significant differences in SRS-22r scores between selective and non-selective fusion groups. At 10-year follow-up, total SRS-22r, self-image, and satisfaction scores stayed consistently improved relative to preoperative status over time, while pain, general function, and mental health declined from 2years onward. Increased age may play a role in enhancing self-image and satisfaction while worsening general function, pain, and mental health. Selectively vs. non-selectively fusing a patient should not hinge on fear of impacting patients' QoL-related measures, as our data suggest improvement in total SRS-22r, self-image, and satisfaction regardless. III.

Residual T1 tilt could lead to poor self-image for patients with Lenke type 1 adolescent idiopathic scoliosis.

Retrospective study. We aimed to investigate the clinical impact and risk factors for residual T1 tilt in patients with adolescent idiopathic scoliosis (AIS). We retrospectively analyzed data of patients with AIS and Lenke type 1 curves who underwent posterior fusion. Residual T1 tilt was defined as T1 tilt > 5° at 2years postoperatively. Patients were classified based on the presence of residual T1 tilt: residual T1 tilt ( +) and residual T1 tilt (-) groups. Radiographic parameters and clinical outcomes were compared between the two groups. Among 128 patients, 44 (34.4%) had residual T1 tilt. The residual T1 tilt ( +) group had a significantly greater preoperative proximal thoracic (PT) curve, greater preoperative T1 tilt, and main thoracic (MT) curve correction rate than the residual T1 tilt (-) group. Shoulder imbalance and neck tilt rates at 2years postoperatively were significantly higher in the residual T1 tilt ( +) group. The residual T1 tilt ( +) group had a significantly worse postoperative self-image score. Multivariate analysis identified the preoperative PT curve magnitude as an independent risk factor for residual T1 tilt. Receiver operating characteristic curve analysis identified a preoperative PT curve cutoff value of 26.5°. Achieving horizontalization of T1 tilt is vital to improve the self-image of patients with Lenke type 1 AIS. The study highlights the clinical impact of T1 tilt and identifies the preoperative PT curve magnitude as a significant independent risk factor. Level 4.

Incidence of and Factors Associated with Spontaneous Correction of Postoperative Shoulder Imbalance in Adolescent Idiopathic Scoliosis Patients: A Retrospective Cohort Study

BackgroundAs far as we know, no study has investigated spontaneous postoperative shoulder imbalance (PSI) correction in adolescent idiopathic scoliosis (AIS) patients. The objective is to assess the incidence of and associated factors for spontaneous PSI correction in AIS patients.MethodsThe study evaluated 144 postoperative AIS patients with PSI aged 10–20 years between 2010 and 2018. An analysis included demographic data and radiographic measurements (Risser grading, Lenke type, upper instrumented vertebra [UIV], and lowest instrumented vertebra [LIV]). Preoperative, postoperative, and follow-up radiographs were evaluated for shoulder parameters: radiologic shoulder height (RSH); T1 tilt angle; clavicle angle (CA); proximal thoracic curve (PTC), main thoracic curve (MTC), and lumbar curve (LC) Cobb measurements; and apical vertebral translation (AVT) of the PTC, MTC, and LC.ResultsSpontaneous PSI correction was observed in 99 (68.75%) patients. The spontaneous correction and nonspontaneous correction groups differed significantly in terms of Lenke-type preoperative LC (23° vs 26°; P = 0.091), postoperative LC (11° vs 8°; P = 0.013), LC at follow-up (13.5° vs 9°; P = 0.028), postoperative AVT of LC (− 0.8° vs − 0.4°; P = 0.033), AVT of LC at follow-up (− 0.7° vs − 0.1°; P = 0.091), PTC at follow-up (16° vs 20°; P = 0.019), and AVT of PTC at follow-up (0° vs -0.3°; P = 0.029). Multivariate analysis identified postoperative T1 tilt and postoperative LC as significantly associated with PSI correction.ConclusionsThe incidence of spontaneous PSI correction is high. Postoperative T1 tilt and postoperative LC are significantly associated with spontaneous PSI correction.

Pedicle Morphology Analysis in Adolescents with Lenke Type 5 Idiopathic Scoliosis in Thai Population

Abstract Background The surgical management of adolescent idiopathic scoliosis (AIS) often incorporates the utilization of pedicle screws, which are three-column construct devices. A comprehensive understanding of the pedicle morphology is essential for determining the appropriate pedicle screw diameter. While previous studies have examined pedicle morphology in Lenke type 1 AIS, there is a scarcity of information about the pedicle morphology in Lenke type 5 AIS, especially in the Thai population. Objective The aim of this study is to analyze the morphology of the thoracolumbar pedicle, specifically the pedicle width and trajectory length on both the concave and convex sides within a sample of the Thai population diagnosed with Lenke type 5 AIS. Materials and Methods In this study, we used computed tomography (CT) measurements to examine the thoracolumbar pedicle morphology in Lenke type 5 AIS patients in the Thai population. We also analyzed the pedicle width and trajectory length on both concave and convex sides in 112 AIS patients with Lenke type 5 curvature. Results A total of 3,808 pedicles from 112 consecutive AIS patients of Lenke type 5 were enrolled in the study. It was observed that the transverse pedicle width was notably smaller on the concave side compared with the convex side in the apical region of the thoracolumbar spine (T12 to L2). Additionally, the pedicle width of T3 was also found to be significantly smaller on the concave side. Moreover, it was noted that the pedicle trajectory length is significantly longer on the concave side, indicating that the concave side in the apical region may have the capacity to accommodate a slightly longer pedicle screw at T3, T6, L2, L3, and L4. Conclusion Our analysis of measurements indicates that the thoracolumbar pedicle morphology in Lenke type 5 AIS among the Thai population typically shows smaller widths and longer trajectory lengths on the concave side. This information enhances our understanding of the appropriate selection of pedicle screw diameter and length for treating Lenke type 5 AIS in the Thai population.

Scoliosis instrumentation alters primary and coupled motions of the spine: An in vitro study using entire thoracolumbar spine and rib cage specimens.

Effects of rigid posterior instrumentation on the three-dimensional post-operative spinal flexibility are widely unknown. Purpose of this in vitro study was to quantify these effects for characteristic adolescent idiopathic scoliosis instrumentations. Six fresh frozen human thoracic and lumbar spine specimens (C7-S) with entire rib cage from young adult donors (26-45 years) without clinically relevant deformity were loaded quasi-statically with pure moments of 5 Nm in flexion/extension, lateral bending, and axial rotation. Primary and coupled motions of all segments were measured using optical motion tracking. Specimens were tested without instrumentation and with posterior rod instrumentations ranging from T2 to L1 (for Lenke Type 2) and from T8 to L3 (for Lenke Type 5) based on survey results among spinal deformity surgeons. Statistical differences were evaluated using the pairwise Friedman test. Primary ranges of motion were significantly (p < 0.05) reduced in all six motion directions in the entire thoracic spine (T1-L1) for both instrumentations, but solely in extension and axial rotation in the entire lumbar spine (L1-S) for T8-L3 instrumentation. Without instrumentation, strong ipsilateral axial rotation during primary lateral bending and strong contralateral lateral bending during primary axial rotation were detected in the thoracic spine (T1-L1) and slight inverse coupled motions in the lumbar spine (L1-S). While coupled axial rotation was significantly (p < 0.05) reduced, especially in the upper thoracic spine (T1-T5) for T2-L1 instrumentation and in the lumbar spine (L1-S) for T8-L3 instrumentation, coupled lateral bending was solely significantly (p < 0.05) reduced in the upper thoracic spine (T1-T5) for T2-L1 instrumentation. Coupled motions in primary flexion and extension were non-existent and not affected by any fixation (p > 0.05). Instrumentation reduces the primary flexibility and diminishes the natural coupling behavior between lateral bending and axial rotation, primarily in the upper thoracic spine, potentially causing correction loss and junctional deformity in the long-term.

Analysis of the effectiveness of two-stage and one-stage surgical treatment for idiopathic scoliosis in children using various methods for deformity mobilization

Introduction. The correction potential of modern systems is limited by the natural mobility of scoliotic deformities, which sometimes require multiple discectomy and osteotomy. Choosing the optimal method of treatment for scoliosis in the thoracic and lumbar regions is difficult due to the variety of approaches and options available for osteotomies. There is no single algorithm for the treatment of idiopathic scoliosis, making it necessary to develop a differentiated approach and treatment strategies. Purpose of the study. To optimize the choice of surgical treatment tactics for children with idiopathic scoliosis based on a compa­rative analysis of the use of one-stage and two-stage surgical treatment. Materials and methods. The study subjects were ninety four patients with idiopathic scoliosis (Lenke type 1–4), operated on between 2017 and 2023. They were divided into three groups: group I (control) — 30 patients underwent one-stage dorsal correction with G1 osteotomy, group II — 31 patients who received two-stage treatment, and group III — 33 patients who underwent a one-stage correction with apical G2 osteotomy. Depending on the initial thoracic kyphotic angle, subgroups were defined as A (hypokyphosis), B (normokyphosis) and C (hyperkyphosis). The minimum follow-up period was 12 months. Results. The frontal balance in all examined patients was in a state of relative compensation, both before surgical treatment and in the postoperative period. When comparing the results in patients from the second and third groups, we found no significant differences (p &gt; 0.05). The second group showed a higher degree of correction of the main arch of spinal deformity (p &lt; 0.05) in the frontal plane compared to the control and third group patients. When analyzing the results of thoracic kyphosis formation, we obtained reliable results in formation more significant indices in patients after surgery in Group II (subgroups A and B), for whom a two-stage applied surgical method was supplemented with anterior release and halo pelvic traction. In Group III (subgroup C), we obtained significant results in thoracic kyphosis indices when using single-stage surgery performed from the dorsal approach supplemented with G2 osteotomy. Conclusion. The condition of the sagittal profile, including the severity of thoracic kyphosis, is an important criterion for choosing the tactics of surgical treatment of scoliotic deformities of the thoracic and lumbar spine. Two-stage treatment, including ventral release and halo-pelvic traction, is recommended for rigid deformities of the thoracic or thoracolumbar spine, under conditions of initial normal kyphosis or hypokyphosis. Severe deformities with initial hyperkyphosis should be corrected preferably in a single stage using posterior surgery, supplemented by G2-osteotomy. The use of G2-osteotomies in patients with initial normal- or hypokyphoses is impractical due to the risk of neurological complications, development of pseudoarthroses, and increase in volume of perioperative bleeding.

Learning curve and long-term outcomes of minimally invasive correction and fusion for adolescent idiopathic scoliosis.

Retrospective analysis. This study sought to report the long-term outcomes of patients that underwent minimally invasive surgery (MIS) correction for Adolescent Idiopathic Scoliosis (AIS) in terms of radiographic, clinical, and patient-reported outcomes. Furthermore, we examined the learning curve of MIS technique over the course of 13years. Both MIS and open techniques are used to surgically address AIS. MIS techniques are purported to preserve the midline spinal musculature and to decrease estimated blood loss (EBL) and hospital length of stay (LOS). Data were collected at a single tertiary care center of all consecutive AIS patients undergoing deformity surgery from January 2008 to October 2021. Demographic, clinical, and radiographic data were collected at various intervals. Descriptive and inferential analyses were conducted. 70 AIS patients were included in the study. Mean patient age was 16.2years of which 95.7% were female, with a mean BMI of 21.7. The majority of the patients were Lenke type 1A (60%) followed by Lenke 1B (18.6%) with mean preop Cobb angle as 52.2°. The mean follow-up was approximately 6years with 35.7% of our cohort meeting the long-term follow-up landmark (> 5years, 2-11). The mean number of spinal levels treated was 9.3 with mean ASA score of 1.7. Overall, mean EBL was 151cc with mean OR of 308min. The mean LOS was 3.94days with postop Day 1 as the initiation of ambulation. Overall, the percent correction at the last visit was significantly greater than preop (Cobb: 77.6%, p < 0.05). Mean loss of correction on follow-ups was less than 5º. The overall revision rate was 2.9%. At 2years postop, 98.6% (69/70) of the patients achieved fusion with 100% (24/24) at 5years, and 96% (24/25) beyond the 5-year mark. Surgeon's technical proficiency in performing MIS for the treatment of AIS corrections was achieved after 23 cases. Based on our cohort's 2-11year follow-up data, we conclude that MIS provides an effective treatment option for AIS reconstruction. Our study indicates that MIS can achieve adequate deformity correction and positive long-term clinical outcomes as indicated by Cobb angle, VAS, ODI, and SRS-22r scores during follow-ups. If the individual goals of AIS surgery can be achieved, consideration should be given to less-invasive techniques. IV.

Zones where reduced implant density leads to correction loss after scoliosis surgery for Lenke 1A adolescent idiopathic scoliosis: a multicenter study.

Investigate zones where implant density should not be reduced in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) Lenke type 1A curves. 126 consecutive patients (118 female and 8 male; mean age: 15.1 ± 2.2years) with Lenke type 1A AIS who underwent PSF using pedicle screw constructs were included. Correction loss which was calculated using immediately postoperative and 2-year postoperative Cobb angle. Implant density was assessed by dividing the instrumented levels into four zones each on the concave and convex sides. The risk factors for significant correction loss were examined using logistic regression analysis. For convex apical zone, correction loss was compared among the three groups of low (0-59%), medium (60-99%), and high (100%) implant density. Multivariate analysis revealed the apical zone of the convex side (Odds ratio [OR] 1.27; 95% confidence interval [CI] 1.01-1.59; P = 0.04) and the peri-apical zone of the convex side (OR 1.33; 95% CI 1.11-1.59; P = 0.002) as independent predictors of significant correction loss. In the convex apical zone, the median (interquartile range) correction loss of the low implant density, medium implant density, and high implant-density groups was 4.8° (1.5°), 5.3° (0.8°), and 2.2° (0.3°), respectively. The median difference was 2.6° (P = 0.048) between the low implant density and high implant-density group and 3.1° (P < 0.001) between the medium implant density and high implant-density group. In PSF for AIS Lenke 1A, low implant density in the convex apical zones were significant factors affecting correction loss at 2years postoperatively. However, the difference in correction loss between groups may not be large enough to consider clinically meaningful. Prospective studies of longer term outcomes are needed to determine whether these results are clinically important.

Usefulness of modified S-line for upper instrumented vertebra selection in adolescent idiopathic scoliosis Lenke type 1C curve.

Determine the effect of using the modified S-line vertebra (MSLV) as the upper instrumented vertebra (UIV) on postoperative trunk balance, L4 tilt, and clinical outcomes in selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS) Lenke type 1C curve. Twenty-eight consecutive patients (all female; mean age: 15.4±2.0 years) with AIS Lenke type 1C curve were retrospectively enrolled. Primary outcome measures were coronal balance (absolute distance between C7 and the center of the sacral vertical line), L4 tilt, and Scoliosis Research Society (SRS)-22r scores at 2 years postoperatively. The group with the MSLV at the UIV was designated as the MSLV group (18 patients), and the group with the MSLV proximal (12 patients) or distal (4 patients) to the UIV was defined as the non-MSLV group. We observed no significant differences between the groups regarding age, LIV and stable vertebra positioning, or preoperative X-ray parameters. Postoperative coronal balance was significantly better in the MSLV group (0.39±0.08 vs. 1.34±0.22 cm; P.

Risk Factors for Postoperative Shoulder Imbalance in Patients With Lenke Type 1 and 2 Scoliosis Treated Using the Vertebral Coplanar Alignment Technique.

This was a multicenter retrospective cohort study. We investigated the incidence of postoperative shoulder imbalance (PSI) and its risk factors in patients with Lenke types 1 and 2 scoliosis corrected using vertebral coplanar alignment (VCA). PSI in scoliosis affects patient quality of life. While other correction methods have reported a high correction rate for the main thoracic curve (MTC) in relation to PSI, this correlation has not been confirmed for the VCA technique. We studied 176 patients with Lenke types 1 and 2 scoliosis who underwent posterior corrective fusion surgery using the VCA technique at 11 institutions. At 2 years postoperatively, patients were divided into two groups based on radiographic shoulder height (RSH): PSI- (RSH<2cm) and PSI+ (RSH ≥2cm) groups. We analyzed the risk factors for PSI. The overall incidence of PSI 2 years postoperatively was 11.4% (20/176), with 9.2% (11/119) and 15.8% (9/57) in patients with Lenke types 1 and 2, respectively. Contrary to a previous study, a high MTC correction rate did not emerge as a risk factor for PSI. Instead, preoperative left shoulder elevation, low postoperative thoracic kyphosis, greater T1 tilt, and high apical vertebral body-to-rib ratio were associated with PSI in patients with Lenke type 1. Preoperative left shoulder elevation and a low postoperative proximal thoracic curve (PTC) correction rate were identified as risk factors for PSI in patients with Lenke type 2. Our results suggest that proper PTC correction, rather than compromising MTC correction, may help prevent PSI in the VCA technique. This method is particularly advantageous for addressing Lenke type 1 scoliosis and yields favorable outcomes in shoulder balance. Patients with preoperative left shoulder elevation, especially Lenke type 2, are at high risk of developing PSI. Level 4.

Relationship between the course of postoperative pelvic axis rotation and shoulder balance in patients with Lenke types 1 and 2 adolescent idiopathic scoliosis

BackgroundPosteroanterior radiographs of patients with adolescent idiopathic scoliosis (AIS) show bilateral differences in the iliac wings. This is due to pelvic axis rotation (PAR) associated with scoliosis. We often encounter cases wherein the PAR changes with surgery and postoperatively. We investigated the course of preoperative PAR and the relationship between PAR and shoulder balance in patients with Lenke 1,2 AIS. MethodsIn total, 28 patients with Lenke 1,2 AIS undergoing scoliosis correction were included. The PAR and shoulder parameters were measured on posteroanterior radiographs. The correlation between the measured parameters and the extent of changes in each parameter was also examined. ResultsEleven patients (39.3 %) underwent preoperative PAR. Six patients (21.4 %) showed a greater change in PAR from 1 week to 2 years postoperatively. The rotation did not change significantly from preoperatively to immediately postoperatively but changed during the first three months postoperatively. The rotation group had significantly more balanced shoulders at 2 years (P = 0.025). The rotation group had a greater change in shoulder balance in the postoperative course significantly (P < 0.05). The extent of change in pelvic rotation from 1 week to 2 years postoperatively correlated with the extent of change in shoulder balance. ConclusionThe PAR in patients with Lenke 1,2 AIS significantly changed during 3 months postoperatively. Patients with Lenke 1,2 AIS with preoperative PAR can be expected to have postoperative shoulder rebalancing.

Posterior Correction and Fusion Using a 4D Anatomical Spinal Reconstruction Technique Improves Postural Stability Under the Eye-Closed Condition in Patients with Adolescent Idiopathic Scoliosis.

Background: Patients with adolescent idiopathic scoliosis (AIS) has been reported to exhibit impaired postural stability. Posterior correction and fusion using four-dimensional (4D) anatomical spinal reconstruction techniques may improve postural stability to correct the spine for optimal anatomical alignment. This prospective study aimed to determine the effect of posterior correction and fusion using a 4D anatomical spinal reconstruction technique on postural stability in the eye-open and eye-closed standing position in patients with thoracic AIS. Methods: Thirty-three patients with AIS, excluding those with Lenke type 5C AIS, participated in the study. The mean and standard deviation of the minimum values of the time-to-boundary (TTB) were determined. All patients were asked to perform the quiet standing position under the eye-open and eye-closed condition on a force plate preoperatively and at 1 week and 2 years postoperatively. The TTB value was calculated from the velocity and distance to the foot boundary of the acquired center-of-pressure data. Results: Under the eye-closed condition, the mean and standard deviation of the minimum TTB were significantly higher at 2 years postoperatively than preoperatively and at 1 week postoperatively. The mean and standard deviation of the minimum TTB values were significantly lower at 1 week postoperatively than preoperatively. Conclusions: The results of this study suggest that surgery using the 4D anatomical spinal reconstruction technique reduces postural stability immediately after surgery; however, it improves postural stability at 2 years compared to the preoperative values.

Tractography analysis results of the trigeminus nerve, which contains fibers responsible for proprioception sensation and motor control in Adolescent Idiopathic Scoliosis.

Cross-sectional Study. It is not yet clear whether the loss of proprioceptive sensation and muscle weakness seen in adolescent idiopathic scoliosis (AIS) is the result of central nervous system dysfunction or secondary to spinal deformity. In our study, in order to find an answer to this question, we examined the microarchitecture of the nervus trigeminus, which is least affected by spinal deformity and contains both proprioceptive sensory and motor fibers. In this single-center, cross-sectional cohort study, 40 Lenke Type 3 (27 female, 13 male) AIS patients and 40 (25 female, 15 male) healthy individuals between the ages of 10-18 years. Tractography of the nervus trigenimus was performed using the "DSI Studio" program. The volumes of the targeted musculus pterygoideus lateralis and musculus pterygoideus medialis were measured using the Insight Segmentation and Registration Tool Kit (ITK -SNAP) program. The data were evaluated using the Statistical Package for the Social Sciences 22.0 program for Windows. There was no significant difference between the two groups in terms of baseline characteristics (p˃0.05). Left nervus trigeminus fiber number and fiber ratio were significantly higher in the control group compared to the scoliosis group p < 0.05. Right and left lateral pterygoid muscle showed lower volume and volume percentage in the scoliosis group compared to the control group (p < 0.05). According to the study data, proprioceptive sensory and motor control dysfunction in AIS is predicted to develop independently of spinal deformity.

Reoperation Rate After Posterior Spinal Fusion Varies Significantly by Lenke Type.

Lenke curve types can vary in their response to treatment. We explored potential differences in reoperation rates, causes, and risk factors among patients with different Lenke types who underwent posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). We studied a multicenter database of patients with AIS who underwent index PSF at ≤21 years of age and had a minimum 2-year follow-up. Baseline and surgical characteristics were collected. Reoperation rates, causes, and risk factors were analyzed by Lenke type. A total of 3,165 patients were included. The mean age was 14.6 years, and most patients were female (81%) and Caucasian (68%). The mean follow-up period was 4.4 years. A total of 138 patients (4.4%) underwent reoperation. The reoperation rate varied by Lenke type (p = 0.02): patients with type-5 curves had the highest reoperation rate (7.2%), and those with type-1 curves had the lowest (3.0%). The most common cause of reoperation was an instrumentation complication. The rate of reoperation due to an instrumentation complication varied by Lenke type (p < 0.01). Compared with patients with type-1 curves, those with type-5 curves had significantly higher rates of reoperation due to implant prominence (odds ratio [OR], 11.7; p = 0.03), loss of fixation (OR, 3.9; p = 0.01), or a broken rod (OR, 7.8; p = 0.02) and those with type-3 curves had a significantly higher rate of reoperation due to loss of fixation (OR, 4.37; p = 0.01). Independent risk factors for reoperation were a major curve magnitude of ≥60° in patients with type-5 curves (adjusted OR [aOR], 4.18; p = 0.04), a major curve correction of ≥40° in patients with type-5 curves (aOR, 3.6; p = 0.04), and a lowest instrumented vertebra (LIV) at or above L1 in patients with type-1 curves (aOR, 2.8; p = 0.02). The reoperation rate for patients with AIS who underwent PSF varied by Lenke type. Patients with type-5 curves had the highest reoperation rate, whereas patients with type-1 curves had the lowest. Patients with Lenke type-5 curves had a higher rate of reoperation due to instrumentation complications. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Return to sports activities following posterior scoliosis correction and instrumented fusion for adolescent idiopathic scoliosis and its correlation to Lenke classification

Introduction: There is a paucity of information or guidelines regarding return to sports activities after posterior scoliosis surgery for adolescent idiopathic scoliosis (AIS). Research Question: Review the rate of return to sports and correlation to Lenke type following surgery for AIS in a tertiary center for pediatric spinal deformity. Materials and Methods: Ninety patients were identified to have undergone surgery for AIS from 2016 to 2017 and were sent a return to sport questionnaire. Sixty-six responses were received and analyzed. For comparison, Lenke classification was divided into Subgroup 1 (Lenke type 1 and 2), Subgroup 2 (Lenke type 3 and 4), and Subgroup 3 (Lenke type 5 and 6). Results: The average age at the time of surgery was 14.81 (11–18) years. There were Lenke 1 (31), Lenke 2 (7), Lenke 3 (12), Lenke 4 (8), Lenke 5 (7), and Lenke 6 (1). The average number of levels fused was 10.27 (7–16). 89.3% of patients returned to school between 1 and 3 months. 19.6% of patients returned to physical education (PE) within 7–12 months, while 31.8% returned to running within 4–6 months. 7.5% of patients did not do PE and 18.2% never ran after surgery. 63.6% of patients returned to contact sports after surgery, majority within 7–12 months. 91% of patients felt that they were able to achieve their preoperative performance level. Comparing the subgroups, 92% of Subgroup 1 returned to school within 2 months, while majority of them returned to PE and running within 6 months. 60% of them returned to the same level of contact/noncontact sports level prior to surgery and 40% within 6 months. Patients in Subgroup 2 and 3 returned later to school. Patients in Subgroup 2 and 3 returned later to school, PE and running with less patients returning to contact/noncontact sports. Conclusion: This study was able to identify Lenke classification as an important predictor of patients returning to school, PE, and running earlier along with return to preoperative levels of contact/noncontact sports.

Excessive posterior placement of upper instrumented vertebra relative to lower instrumented vertebra as a predictor of proximal junction kyphosis after selective spinal fusion for adolescent idiopathic scoliosis Lenke type 5C curves.

We defined sagittal S-line tilt (SSLT) as the tilt of the line connecting the upper instrumented vertebra and the lower instrumented vertebra. This study aimed to: (1) examine the correlation between SSLT and proximal junctional angle (PJA) change values, and (2) determine the cut-off value of SSLT with respect to proximal junctional kyphosis (PJK) occurrence. Eighty-six consecutive patients (81 female and 5 male; mean age: 15.8years) with Lenke 5C AIS who underwent posterior selective spinal fusion. Pearson's correlation coefficients were used to examine the relationship between preoperative SSLT and changes in PJA from preoperative to 2years postoperative. The impact of SSLT on PJK at 2years after surgery was assessed using a receiver operating characteristic (ROC) curve. We observed a moderate positive correlation between preoperative SSLT and change in PJA (R = 0.541, P < 0.001). We identified 18 patients (21%) with PJK at 2years postoperative. Mean preoperative SSLT in the PJK group and the non-PJK group differed significantly at 23.3 ± 4.1° and 16.1 ± 5.0°, respectively (P < 0.001). The cut-off value of preoperative SSLT for PJK at 2years postoperative was 18° in ROC curve analysis, with a sensitivity of 94%, specificity of 68%, and area under the ROC curve of 0.868. In selective lumbar fusion for AIS Lenke type 5C curves, preoperative SSLT was significantly correlated with PJA change from preoperative to 2years postoperative. SSLT was a predictor of PJK occurrence, with a cut-off value of 18°.