Objective:To explore a selective resection strategy for combined lumbosacral hemivertebra (LSHV) and thoracolumbar hemivertebra/lumbar hemivertebra (TLHV/LHV) double-balanced hemivertebra deformities.Methods:A retrospective analysis was conducted on 21 patients aged over 10 years with lumbosacral and thoracolumbar or lumbar combined hemimetameric segmental shift (HMMS) deformities who underwent surgery at Nanjing Drum Tower Hospital between May 2009 and October 2022. The cohort included 7 males and 14 females, with a mean surgical age of 21.5±10.9 years (range: 12-55 years) and a mean follow-up duration of 32.8±15.9 months (range: 24-74 months). Patients were divided into two groups based on preoperative coronal balance: the balanced group (Type A) and the unbalanced group (Type C). Radiographic parameters, including the major Cobb angle, lumbosacral take-off angle, kyphotic angle, coronal balance distance (CBD), and the deviation of the upper instrumented vertebra (UIV), were measured preoperatively, postoperatively, and at the final follow-up. Surgical complications were also recorded.Results:Of the 21 patients, 11 were classified as preoperatively balanced, and 10 as unbalanced. The deformity angular ratio of thoracolumbar to lumbosacral curves was significantly higher in the balanced group than in the unbalanced group (0.9±0.3 vs. 0.6±0.2; t=2.143, P=0.045). The preoperative main curve Cobb angles in the balanced and imbalanced groups were 71.3°±22.3° and 58.6°±8.2°, respectively. One week postoperatively, these angles were reduced to 38.4°±17.6° and 31.3°±5.6°, and were maintained at 40.0°±18.1° and 32.6°±5.6° at the final follow-up, all differences were statistically significant ( P<0.05). The preoperative lumbosacral take-off angles were 37.5°±9.1° in the balanced group and 36.7°±7.7° in the imbalanced group, which decreased to 18.4°±9.4° and 19.2°±5.5° at 1 week postoperatively, and remained at 19.4°±10.1° and 19.6°±5.8° at the final follow-up. These changes were also statistically significant ( P<0.05). In the balanced group, the UIV tilt angle, the CBD and the deviation of the UIV, were all significantly reduced compared to preoperative values ( P<0.05). Among the 21 patients, LSHV resection was performed in 15 cases, and TLHV/LHV resection was performed in 7 cases. Among the 15 patients with kyphosis, TLHV/LHV resection was performed in 6 cases. In the balanced group, 9 patients maintained type A postoperatively, including 4 patients with LSHV resection, 2 with TLHV/LHV resection, 2 with both LSHV and TLHV/LHV resection, 1 without resection of both hemivertebra. Two patients in the balanced group who underwent TLHV/LHV resection experienced postoperative deterioration to type C. In the unbalanced group, 8 cases with LSHV resection improved to type A, while 1 case with LSHV resection and 1 case with neither resection maintained C-type. In the LSHV resection group, CBD improved from 29.8±15.2 mm to 13.9±5.7 mm postoperatively and remained stable at 14.6±8.6 mm at final follow-up. Only 1 patient in this group experienced worsened coronal imbalance. In contrast, in the non-LSHV resection group, CBD worsened from 17.2 ± 8.7 mm to 19.7±12.1 mm postoperatively, progressing further to 20.5±13.0 mm at follow-up. Three patients in this group had worsening coronal imbalance, and 2 required revision surgery. Reported complications included 3 cases of internal fixation fracture, 1 case of proximal junctional kyphosis, and 1 case of acute incision infection. Conclusions:Effective resection of lumbosacral hemivertebrae is the preferred selective strategy, particularly for patients with preoperative coronal imbalance, as it significantly reduces the risk of worsening coronal imbalance and internal fixation-related complications. However, selective resection involving only TLHV or LHV without addressing LSHV in preoperatively balanced patients may increase the risk of postoperative coronal imbalance.

Objective:To investigate the effect of anterior and posterior selective fusion strategy on evolution of coronal pattern in patients with Lenke 5C adolescent idiopathic scoliosis (AIS) and whether upper end vertebra (UEV)-1 strategy in anterior surgery would have an effect on postoperative coronal balance.Methods:A total of 108 Lenke 5C AIS patients with at least 2 years follow-up who underwent anterior or posterior selective thoracolumbar fusion surgery from January 2005 to December 2020 were enrolled, with 51 patients in the anterior group and 57 patients in the posterior group. The patients were categorized into three groups (type A, C 7PL-CSVL<20 mm; type B, C 7PL-CSVL ≥20 mm with C 7PL toward the concave side of the main curve; and type C, C 7PL-CSVL≥20 mm with C 7PL toward the convex side of the main curve) to investigate the evolution of coronal balance of each preoperative coronal pattern at the anterior and posterior groups. Parameters such as thoracolumbar Cobb angle, rate of coronal imbalance, and SRS-22 score were recorded at preoperative, 1 week postoperatively, and final follow-up in both groups. Results:The differences of basic date between the two groups were not statistically significant except for the fusion level (5.2±0.7 vs. 5.6±0.9, t=2.497, P=0.014). In the anterior group, a total of 27 patients with preoperative type A, 23 patients with preoperative type A maintained type A at the 1 week postoperatively, and 2 of them were converted to type C at the final follow-up. Four patients with preoperative type A converted to type C at the 1 week postoperatively, and all of them returned to type A at the final follow-up. A total of 23 patients with preoperative type C, four patients with preoperative type C maintained type C at the 1 week postoperatively, and one of them maintained type C at the final follow-up. Nineteen patients with preoperative type C converted to type A at the 1 week postoperatively, and all of them maintained type A at the final follow-up. In the posterior group, a total of 26 patients with preoperative type A, 22 patients with preoperative type A maintained type A at the 1 week postoperatively, and only 2 of these patients converted to type C at the final follow-up. Four of the preoperative type A patients converted to type C at the 1 week postoperatively, and all of them returned to type A at the final follow-up. A total of 29 patients with preoperative type C, thirteen patients with preoperative type C maintained type C at the 1 week postoperatively, and 7 of them maintained type C at the last follow-up. Sixteen patients with preoperative type C converted to type A at the 1 week postoperatively, of whom two converted to type C at the final follow-up. For patients with preoperative type C the rate of coronal imbalance was significantly lower in the anterior group than in the posterior group both in the immediate postoperative period (17% vs. 45%, P<0.05) and at the final follow-up (4% vs. 31%, P=0.038). The rate of coronal imbalance at final follow-up was significantly lower in the UEV-1 group than in the UEV group in the posterior approach (3% vs. 38%, P<0.05), and there was no difference between the two groups in the anterior approach. There were no significant differences in radiographic parameters and SRS-22 scores between the two groups, except for the thoracic Cobb angle at the final follow-up, which was greater in the anterior group than in the posterior group at the final follow-up (19.5±7.3 vs.16.4±5.6, t=2.427, P=0.017). Multivariate logistic regression analysis revealed that anterior surgery and Risser were risk factors for postoperative CIB of preoperative type C ( OR=21.138, P=0.030 and OR=0.406, P=0.048 respectively). Conclusion:For patients with preoperative type A, both anterior and posterior procedures lead to a satisfactory reconstruction of coronal balance. In patients with preoperative type C, anterior surgery acquire a better reconstruction of coronal balance. The strategy of proximal UEV-1 was similar to the strategy of UEV in terms of restoring coronary balance in anterior approach and it was unable to lower the rate of postoperative coronal imbalance. In contrast, UEV-1 strategy in posterior surgery was effective in reducing the rate of postoperative coronal imbalance.

Objective:To analyze the selection of internal fixation methods, surgical outcomes, and complications in patients with Neurofibromatosis Type 1 (NF1) accompanied by dystrophic lumbosacral deformities, and to evaluate the indications for pelvic fixation.Methods:A retrospective analysis was conducted on 21 patients with NF1 and associated dystrophic lumbosacral malformations (L 4 to sacrum) who underwent spinal deformity correction surgery at Nanjing Drum Tower Hospital from January 2009 to November 2022. The cohort included 11 males and 10 females, with a mean surgical age of 15.4±4.7 years (range, 7-24 years). Patients were divided into two groups based on whether pelvic fixation was performed: 10 patients in the non-pelvic fixation group (NP group) and 11 in the pelvic fixation group (P group), where fixation involved second sacral alar-iliac (S 2AI) screws or iliac screws. Radiographic parameters, including the Cobb angle of the lumbosacral fractional curve, main curve, and focal kyphosis, were compared preoperatively, postoperatively, and at the last follow-up. Results:The NP group had a significantly lower mean age (13.2±4.9 years) compared to the P group (17.5±3.5 years; t=2.287, P=0.034). Spinal instability (rotational subluxation or spondylolisthesis) due to dystrophic changes was observed in 2 patients in the NP group and 8 in the P group, a statistically significant difference (χ 2=5.838, P=0.030). In the P group, five patients underwent unilateral fixation and six underwent bilateral fixation. Implant types included 2 cases with iliac screws, 1 case with iliac screws plus S 2AI, and 8 cases with S 2AI screws alone. The utilization rate of hooks was significantly higher in the NP group (12.6%±11.5%) compared to the P group (3.5%±6.9%; t=2.230, P=0.038). The preoperative Cobb angle of the lumbosacral fractional curve was significantly smaller in the NP group (13.8°±9.0°) than in the P group (25.5°±13.9°; t=2.228, P=0.039). Postoperatively, the angles were corrected to 6.3°±6.1° and 6.4°±5.3°, respectively ( t=0.901, P=0.969), with correction rates of 57.3%±13.6% and 74.1%±17.8% ( t=2.369, P=0.029). At final follow-up, the angles remained stable (6.6°±6.6° vs. 6.3°±4.8°; t=0.116, P=0.909). For the main curve, preoperative Cobb angles were 52.5°±15.1° (NP) and 61.1°±16.9° (P; t=1.200, P=0.246), corrected to 31.3°±13.8° and 28.0°±8.4°, respectively ( t=0.646, P=0.526). Correction rates were 41.3%±13.0% in the NP group and 53.2%±11.6% in the P group ( t=2.206, P=0.037). At the final follow-up, these values were 32.4°±14.2° and 31.7°±10.3° ( t=0.133, P=0.896). Focal kyphosis, seen in 9 patients, was corrected from 19.7°±10.9° preoperatively to -13.6°±9.5° postoperatively, and remained at -14.1°±9.6° at the final follow-up ( F=33.547, P<0.001). Multi-rod systems were used in 6 cases (NP group) and 7 cases (P group), with no significant difference (χ 2=0.153, P=0.926). Two patients in the NP group developed coronal decompensation three years postoperatively, and one required revision surgery. In the P group, rod breakage occurred in 3 patients, two of whom underwent revision. Conclusions:Dystrophic rotational subluxation or spondylolisthesis of the lumbosacral spine is a primary indication for pelvic fixation in patients with NF1-associated deformities. However, complications related to internal fixation remain common. The combined use of a multi-rod screw-hook hybrid system, particularly when extending across the lumbosacral region, may reduce the risk of instrumentation failure.

Objective:To evaluate the relationship between postoperative changes in femoral head coverage (FHC) after S 2-Alar-Iliac (S 2AI) screw fixation and the development of sagittal imbalance during follow-up in patients with adult spinal deformity (ASD), providing insights for clinical assessment and treatment strategies. Methods:A consecutive cohort of 98 ASD patients who underwent S2AI fixation between September 2019 and September 2021 was retrospectively analyzed. Patients were divided into two groups based on changes in femoral head coverage (ΔFHC): the FHC-C group (upper quartile ΔFHC, 25 cases) and the FHC-NC group (lower quartile ΔFHC, 24 cases). Additionally, patients were classified into proximal junctional kyphosis (PJK) and non-PJK groups based on their clinical outcomes at the last follow-up. Standing full-spine anteroposterior and lateral X-rays were taken preoperatively, postoperatively, and at the two-year follow-up to measure and document the following spinal parameters: Cobb angle, proximal lumbar lordosis (PLL), distal lumbar lordosis (DLL), lumbar lordosis (LL), lordosis distribution index (LDI), sagittal vertical axis (SVA), coronal balance distance (CBD), thoracic kyphosis (TK), T 1 pelvic angle (T 1PA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), PI-LL, and proximal junctional angle (PJA). Parameters related to hip joint coverage included: femoral head coverage (FHC), lateral center-edge angle (LCE angle), acetabular index (AI), Sharp angle, and extrusion index (EI). Comparisons of radiographic indicators between the two groups were performed at preoperative, postoperative, and final follow-up assessments. The visual analogue scale (VAS) was used to evaluate the hip pain and back pain. Results:At final follow-up, the incidence of PJK was significantly higher in the FHC-NC group [37.5% (9/24)] compared to the FHC-C group [16.0% (4/25)] (χ 2=3.952, P=0.042). Moreover, the increase in sagittal vertical axis (ΔSVA) was significantly greater in the FHC-NC group (35.9±44.7 mm vs. 14.6±31.8 mm, t=2.216, P=0.031). Patients with PJK had significantly higher preoperative T 1PA (36.8°±10.8° vs. 31.9°±18.4°, t=2.150, P=0.034) and lower immediate postoperative ΔFHC (1.7%±1.5% vs. 3.3%±2.5%, t=2.987, P=0.004), as well as lower changes in lateral center-edge angle during follow-up (0.3°±3.0° vs. 1.1°±8.9°, t=2.334, P=0.022). Pearson correlation analysis revealed significant negative correlations between postoperative ΔFHC and both ΔSVA ( r=-0.374, P=0.008) and proximal junctional angle changes (ΔPJA, r=-0.429, P=0.006). Additionally, increases in VAS leg pain scores correlated negatively with immediate postoperative FHC ( r=-0.314, P=0.025) and ΔFHC ( r=-0.298, P=0.031). Logistic regression indicated that immediate postoperative ΔFHC was a protective factor against PJK [ OR=0.722, 95% CI (0.541, 0.963), P=0.009), with a ROC-determined optimal ΔFHC cut-off of 3.90% (AUC=0.723, Youden index=0.847). Conclusions:Postoperative evaluation of femoral head coverage is clinically important for ASD patients undergoing S2AI screw fixation. A pre-to-post ΔFHC below 3.90% may indicate reduced hip compensation capacity, increasing risks for hip pain, sagittal imbalance progression, and PJK postoperatively.

Objective:To predict mechanical complications (MC) following spinal deformity surgery for adult spine deformity (ASD) using machine learning models, identify key risk factors, and develop a visualizable tool for individualized risk assessment.Methods:Clinical and radiological data from 525 patients with ASD who underwent surgery in our hospital between January 2017 and December 2021 were collected. Patients were randomly assigned to a training set (70%) and a test set (30%) for model development. The cohort included 88 males and 437 females, with a mean age of 42.2±18.1 years. Variables included demographic data, comorbidities, local and systemic radiological parameters, paraspinal muscle fat infiltration (FI), and vertebral bone quality (VBQ) scores. Multiple machine learning algorithms: Random Forest (RF), Gaussian Naive Bayes (GNB), Light GBM, Support Vector Machine (SVM), XGBoost (XGB), and Logistic Regression (LR) were trained and evaluated. Model performance was compared using the receiver operating characteristic curve (ROC) and precision-recall curve (PRC). SHAP (Shapley Additive Explanations) was used to rank risk factors, while LIME (Local Interpretable Model-Agnostic Explanations) was applied to visualize MC risk in individual cases.Results:Of the 525 patients, 135 (25.7%) developed postoperative MC. Among these, 80 (59.3%) experienced proximal junction kyphosis or failure (PJK/PJF), 7 (5.2%) had distal junction kyphosis or failure (DJK/DJF), 28 (20.7%) sustained rod fractures, and 29 (21.5%) showed significant loss of correction. In the validation cohort, the RF model achieved the highest area under the curve (AUC=0.80), followed by GNB (0.77), XGB (0.76), LR (0.74), LightGBM (0.73), and SVM (0.66). The RF model also demonstrated the best PRC value (0.58), highest sensitivity (0.65), and lowest Brier score (0.20). GNB, Light GBM, and LR models achieved the highest accuracy (0.78 each), while LightGBM exhibited the highest specificity (0.93). SHAP analysis identified higher preoperative VBQ scores, larger T 1 pelvic angle (TPA), and higher paraspinal muscle FI as the main risk factors for MC. Based on the RF model, a LIME-based tool was successfully constructed for individualized MC risk estimation. Conclusion:The RF model demonstrated the best overall predictive performance for MC. A machine learning-based prediction model has the potential to provide valuable guidance for surgical decision-making in ASD patients.

Objective:To compare the incidence of instrumentation-related complications and health-related quality of life following pelvic fixation using iliac screws (IS) or second sacral alar-iliac (S 2AI) screws in adult spinal deformity (ASD). Methods:A retrospective cohort study was conducted on 108 ASD patients who underwent posterior corrective fusion and fixation extending to the pelvis at Nanjing Drum Tower Hospital between September 2010 and April 2021. According to the type of pelvic fixation, patients were divided into an IS group ( n=34; 12 males, 22 females; mean age 53.7±11.1 years, range 28-73 years) and an S 2AI group ( n=74; 23 males, 51 females; mean age 52.8±8.6 years, range 27-72 years). Pre- and post- operative standing anteroposterior and lateral radiographs were evaluated for Cobb angle, coronal balance distance (CBD), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). At 2 years postoperatively, health-related quality of life were assessed using the Scoliosis Research Society-22 questionnaire (SRS-22), Oswestry disability index (ODI), and visual analogue scale (VAS) for pain. Instrumentation failure related to pelvic fixation during follow-up was recorded. Results:All patients completed follow-up. Mean follow-up duration was 28.5±3.6 months (range 24-37 months) in the IS group and 28.1±4.3 months (range 24-43 months) in the S 2AI group. Postoperatively, both groups showed significant improvement in Cobb angle, CBD, TK, LL, SVA, PT, and SS compared to baseline ( P<0.05), whereas PI remained unchanged ( t=0.664, P=0.509; t=1.227, P=0.222). Preoperative PT was greater in the IS group than in the S 2AI group (33.6°±8.7° vs. 29.3°±9.6°, t=2.228, P=0.028). No significant intergroup differences were observed in any other pre- or post- operative radiographic parameters ( P>0.05). Pelvic fixation failure occurred in 31 patients (28.7%, 31/108). Patients with fixation failure had a longer fusion segment extension than those without failure (12.0±2.8 vs. 10.8±2.4 segments; t=2.256, P=0.026). In the IS group, complications comprised 3 cases of screw loosening (8.8%), 2 of screw breakage (5.9%), and 4 of rod fracture within the pelvic region (11.8%), including 1 case with concurrent screw and rod failure. In the S 2AI group, there were 21 cases of screw loosening (28.4%) and 2 of screw breakage (2.7%). Screw loosening was less frequent in the IS group than in the S 2AI group (χ 2=5.154, P=0.023), whereas pelvic rod fracture was more common in the IS group (χ 2=9.041, P=0.003). Screw breakage rates did not differ significantly ( P>0.05). Mean VAS, ODI, and SRS-22 scores in the IS group were 3.2±2.4, 24.9%±18.8%, and 3.2±0.8, respectively; corresponding to 2.5±1.8, 18.9%±10.9%, and 3.3±0.6 in the S 2AI group. ODI was significantly higher in the IS group ( t=2.062, P=0.042), whereas VAS and SRS-22 were comparable ( P>0.05). Among S 2AI patients, VAS and ODI scores did not differ significantly between those with and without screw loosening ( P>0.05). Conclusions:The post-operative incidence of pelvic fixation failure following ASD surgery reached 28.7%. The predominant failure mode with S 2AI was screw loosening, whereas IS was more frequently complicated by rod fracture. Early postoperative health-related quality of life was superior with S 2AI screws compared with iliac screws.

Objective:To investigate the risk factors for postoperative coronal imbalance in patients with type A degenerative scoliosis and to refine the Qiu classification by reclassifying type A patients.Methods:A retrospective analysis was conducted on the clinical data of patients with type A degenerative scoliosis classified by the Qiu classification who underwent corrective surgery at our hospital from January 2017 to April 2022. A total of 69 patients were enrolled in the study, including 3 males and 66 females, with an age of 60.6±6.8 years (range: 47-71 years). Based on the preoperative CBD, type A patients were further divided into three subtypes: Aa with CBD≤1 cm, Ab with CBD>1 cm with C 7 plumb line deviation toward the concave side, and Ac with CBD>1 cm with C 7 plumb line deviation toward the convex side. The incidence of coronal imbalance was compared among subtypes. During follow-up, patients with CBD ≤3 cm were classified as balanced, and those with CBD>3 cm as imbalanced. Radiographic parameters including coronal Cobb's angle (CA), CBD, L 4 tilt angle, L 5 tilt angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sagittal vertical axis (SVA) were measured in the standing radiographs preoperatively, 2-weeks postoperatively and 2-years follow-up. Differences in radiographic parameters between balanced and imbalanced groups were compared, and binary logistic regression was used to identify risk factors for postoperative coronal imbalance. Results:In the imbalanced Group (22 patients), there were 6 patients of type Aa (27%), 5 patients of type Ab (23%), and 11 patients of type Ac (50%), and in the balanced Group (47 patients), there were 20 patients of type Aa (43%), 18 patients of type Ab (38%), and 9 patients of type Ae (19%). The difference in subtype distribution between the two groups was significant (χ 2=6.939, P=0.029). The CBD in the imbalanced group was significantly larger than in the balanced group at the 2-years follow-up (4.18±0.86 cm vs. 1.31±0.78 cm, t=-13.813, P<0.001). The preoperative L 4 tilt angle was significantly larger in the imbalanced group compared to the balanced group (23.59°±6.86° vs. 17.64°±8.34°, t=-2.914, P=0.005). And the postoperative and 2-years follow-up L 4 tilt angles were also significantly larger than the balanced group (18.6°±5.5° vs. 11.5°±5.7°, t=-4.904, P<0.001; 18.0°±5.6° vs. 11.1°±5.7°, t=-4.691, P<0.001). Regression analysis identified the Ac type [ OR=3.937, 95% CI(1.07, 14.55), P=0.040] and excessive postoperative L 4 tilt angle [ OR=1.288, 95% CI(1.09, 1.52), P=0.003] as risk factors for postoperative coronal imbalance in type A patients. Conclusions:In the A-type of Qiu classification, patients with preoperative CBD>1 cm and trunk tilting towards the convex side (Ac type), as well as those with a large L 4 tilt angle after surgery, are more likely to experience coronal plane imbalance after surgery.

Objective:To investigate the difference of Roussouly ideal classification in predicting postoperative proximal junctional kyphosis (PJK) between adult degenerative spinal deformity patients with and without pelvic fixation and the potential reasons.Methods:From January 2017 to January 2020, a total of 95 patients (4 males, 91 females; with an average age of 62.03±6.30 years) with degenerative spinal deformities were retrospectively analyzed. There were 35 patients in the non-pelvic group (1 male, 34 females) and 60 patients in the pelvic group (3 males, 57 females). The radiographic parameters included coronal Cobb's angle (CA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), T1 pelvic angle (TPA), and proximal junctional angle (PJA) were measured in the standing radiographs preoperatively, postoperatively at 2 weeks, and 2-year follow-up. Changes in PT and SS were calculated for patients at 2 weeks and the 2-year follow-up. Based on the revised Roussouly classification, 95 patients were classified into different types preoperatively, postoperatively at 2 weeks, and during the 2-year follow-up. Changes in the classification of patients were documented postoperatively at 2 weeks. Roussouly types were determined using preoperative pelvic parameters, and a match was defined when the 2-week postoperative classification aligned with the ideal type. The occurrence of PJK and the relationship with classification matching were recorded in the group. Independent t-tests were used for intergroup comparisons of radiographic parameters, and chi-square tests were employed to assess classification changes and predictive accuracy of the Roussouly classification. Results:Preoperative PT, TPA and SVA in non-pelvic group were significantly smaller than those in pelvic group, and preoperative SS and LL larger than those in pelvic group ( P<0.05). The changes of PT and SS in non-pelvic group were significantly lower than those in pelvic group 2 weeks after surgery ( P<0.05). The proportion of classification changes in the pelvic group was significantly higher than that in the non-pelvic group (60% vs. 34%, χ 2=5.847, P=0.016). Among the 95 patients, a total of 29 experienced PJK during the follow-up, with 3 cases progressing to PJF. The incidence of PJK in mismatched patients was 37% with no significant difference compared with matched patients (19%) (χ 2=3.357, P=0.067). In the sacral spine group of 60 patients, 22 experienced PJK, with 3 cases progressing to PJF. Among them, 19 patients with PJK had a classification mismatch with the ideal classification at 2 weeks postoperatively. The PJK incidence was significantly higher in mismatched patients (45%) compared to matched patients (17%) (χ 2=4.429, P=0.035). In the non-pelvic group, 7 patients developed PJK, with 3 mismatched cases. The PJK incidence in mismatched vs. matched patients was 18% vs. 22%, showing no significant difference (χ 2=0.114, P=0.735). Conclusions:For the patients with degenerative spinal deformity, pelvic fixation leads to a more complete restoration of the ideal Roussouly classification. Restoration of the Roussouly type in patients with pelvic fixation is a reliable predictor of postoperative PJK. However, in patients without pelvic fixation, the alignment with the ideal Roussouly classification does not significantly correlate with PJK development.

Objective:To evaluate the clinical outcomes of corrective surgery in patients with different subtypes of "Ω"-type severe scoliosis.Methods:A retrospective analysis was conducted on 79 patients with "Ω"-type severe scoliosis treated at Nanjing Drum Tower Hospital from August 2010 to July 2020. The cohort included 37 males and 42 females, with a mean age of 21.4±7.4 years (range, 8-52 years). The mean duration of preoperative halo traction was 72.6±27.5 days (range, 14-150 days). Etiologies included congenital scoliosis (33 cases), idiopathic scoliosis (27 cases), Marfan syndrome (9 cases), neurofibromatosis (8 cases), and neuromuscular disorders (2 cases). Based on the classification by Karikari et al., 58 patients were classified as type 2P, 13 as type 2D, and 8 as type 2PD. Outcome measures included coronal and kyphotic Cobb angles, the Scoliosis Research Society-22 (SRS-22) questionnaire, Oswestry disability index (ODI), and visual analog scale (VAS).Results:All surgical procedures were successfully completed, and all patients were followed up for an average of 27.5±3.9 months (range, 24 to 40 months). The duration of Halo gravity traction was 72.6±27.5 days (range, 14-150 days). In the 2D group, the changes after traction were 26.0°±12.5° for the coronal Cobb angle and 10.1°±7.9° for the kyphotic Cobb angle. In the 2PD group, the traction effect was 13.4°±5.7° for the coronal and 8.3°±5.9° for the kyphotic Cobb angle. In the 2P group, the preoperative coronal Cobb angle was 128.9°±29.1°, postoperative was 84.5°±24.5°, and at the last follow-up was 87.7°±25.0°, yielding a correction rate of 34%±12%. The kyphotic Cobb angle in this group changed from 112.9°±27.1° preoperatively to 77.6°±22.9° postoperatively, and 80.2°±22.8° at the final follow-up, corresponding to a correction rate of 30%±16%. In the 2D group, the coronal Cobb angle was 113.1°±19.9° preoperatively, 71.2°±16.3° postoperatively, and 73.8°±16.3° at the final follow-up, with a correction rate of 37%±11%. The kyphotic Cobb angle in this group was 87.2°±14.0° preoperatively, 61.6°±18.5° postoperatively, and 65.1°±18.5° at the final follow-up, with a correction rate of 31%±22%. In the 2PD group, the coronal Cobb angle improved from 119.6°±29.0° preoperatively to 78.3°±20.8° postoperatively, and 87.0°±23.0° at the last follow-up, corresponding to a correction rate of 35%±8%. The kyphotic Cobb angle in this group was 124.6°±16.8° preoperatively, 82.1°±19.9° postoperatively, and 90.9°±16.9° at the final follow-up, with a correction rate of 33%±16%. At the last follow-up, SRS-22 scores across all four domains had improved in all three groups compared to preoperative values. In the 2PD group, however, the differences in the pain and self-image domains before and after surgery were not statistically significant ( P>0.05), while improvements in the other domains were significant ( P<0.05). No statistically significant differences were observed among the three groups either preoperatively or at the final follow-up ( P>0.05). Conclusion:Combined Halo-gravity traction and spinal corrective surgery are effective in improving both radiographic and functional outcomes in patients with "Ω"-type severe scoliosis. Nonetheless, patients in the 2PD subtype demonstrate reduced traction responsiveness and relatively limited postoperative recovery compared to the 2P and 2D subtypes.

Objective: To assess the effectiveness of vertebral cement augmentation (VCA) at upper instrumented vertebra (UIV) and UIV+1 in preventing proximal junction complications in correction surgery for adult spinal deformity patients. Methods: A literature search was conducted on Web of Science, PubMed, and Cochrane Library databases for comparative studies published before December 30th, 2024. Two reviewers independently screened eligible articles based on the inclusion and exclusion criteria, assessed study quality with Newcastle-Ottawa scale, and extracted data like study characteristics, surgical details, primary and secondary outcomes. Data analysis was performed using Review Manager 5.4 and Stata software. Results: Of all 513 papers screened, a meta-analysis was conducted on 7 articles, which included 333 cases in the VCA group and 827 cases in the control group. Patients in the VCA group had significantly older age and lower T score than patients in the control group. Although there was no statistically significant difference in the incidence of proximal junctional failure between the 2 groups, the results of the meta-analysis showed that the incidence of proximal junctional failure and the need for revision surgery were reduced by 36% and 71%, respectively, in the VCA group. One study reported 2 clinically silent pulmonary cement embolism and 1 patient requiring surgical decompression for cement leak into the spinal canal. Conclusion This meta-analysis supported the use of VCA in corrective surgery for spinal deformities patients, especially in patients with advanced age and osteoporosis.