Asian Spine Journal最新文献

Study design: Single-center retrospective study.

Purpose: By utilizing three-dimensional (3D) reconstruction models, our study aimed to investigate the three-dimensional changes in vertebral body tethering (VBT) and assess the relationship between axial-plane parameters and postoperative outcomes.

Overview of literature: Previous studies mainly focused on coronal plane correction but lacked investigation on axial plane changes following VBT.

Methods: We included consecutive patients who underwent VBT in our institution (Queen Mary Hospital and Duchess of Kent Children's Hospital, Hong Kong) from February 2019 to April 2024. We used EOS radiographs to generate 3D reconstruction models, and parameters were analyzed preoperatively, immediately postoperatively, 1 year postoperatively, and 2 years postoperatively. The primary outcomes were changes in coronal, axial, and sagittal profiles at different time points. Secondary outcomes included the relationship between axial parameters with short-to-medium term changes in coronal/sagittal profiles.

Results: We included 44 patients (seven males, 37 females) with 58 instrumented curves, with an average follow-up of 36.3±17.1 months. The mean Cobb angle, apical vertebral rotation (AVR), and maximal vertebral rotation (MVR) improved from 48.0°±10.7°, 9.1°±5.7°, and 13.4°±5.7° preoperatively to 22.3°±8.9°, 6.2°±4.8°, and 9.8°±4.3° postoperatively, respectively, with correction maintained at 2 years. Preoperative AVR, MVR, and intraoperative derotation were significantly correlated with 1-year and 2-year correction rate and curve regression (Pearson correlation coefficient [r ]=0.35-0.63; p <0.001). Multivariate analysis confirmed AVR derotation and preoperative MVR as significant predictors for the 1-year correction rate. Tether breakage occurred in 27.6% (16/58) of patients.

Conclusions: VBT was effective in correcting coronal and axial deformity at 2 years, but most correction occurred intraoperatively. Axial parameters were predictive for postoperative outcomes, with increased preoperative rotation associated with greater coronal correction. More aggressive derotation corresponded to greater correction. To improve surgical outcomes, clinicians should aim to achieve adequate correction by screw positioning and appropriate tensioning.

Adult spinal deformity (ASD) is a complex condition associated with significant disability and reduced health-related quality of life (HRQOL). Surgical correction has increasingly emphasized restoration of sagittal alignment; however, the optimal radiographic targets and their relationships to clinical outcomes and mechanical complications remain subjects of debate. This narrative review summarizes five major alignment strategies in ASD surgery and examines their relevance to HRQOL and the prevention of proximal junctional kyphosis/ failure (PJK/PJF). The Scoliosis Research Society-Schwab classification introduced the first standardized thresholds for sagittal imbalance that demonstrated strong associations with HRQOL, although its ability to predict PJK/PJF is limited. Age-adjusted alignment goals highlighted the importance of avoiding overcorrection, demonstrating that functionally appropriate targets in older patients can reduce junctional complications while maintaining HRQOL benefits. The Global Alignment and Proportion (GAP) score proposed a proportionality-based framework and demonstrated early promise in predicting mechanical complications; however, subsequent validation studies have reported inconsistent results across different populations. The Roussouly classification emphasized restoration of a patient's inherent sagittal profile, with lower complication rates observed when type-matched correction was achieved. More recently, vertebral-pelvic angle-based metrics, including the T1 pelvic angle and the T4-L1-hip axis, have shown strong correlations with HRQOL and PJK risk while offering reproducible and practical intraoperative applicability. Although each system provides valuable insights, no single approach is universally superior. Future research should focus on integrating radiographic, biological, and functional factors into predictive models and validating these approaches through prospective multicenter studies to better guide individualized alignment strategies.

Study design: Retrospective multicenter cohort study.

Purpose: This study aimed to evaluate the incidence of cage subsidence and its impact on the clinical outcomes of anterior-posterior spinal fixation (APSF) for osteoporotic vertebral fractures (OVFs). It also aimed to identify the risk factors for cage subsidence.

Overview of literature: The risk factors for cage subsidence after APSF for OVFs remain unclear.

Methods: This multicenter retrospective cohort study included patients who underwent combined APSF using an expandable cage system, with a minimum 1-year follow-up at multiple centers. Patients were divided into cage subsidence (n=53) and non-subsidence (n=47) groups. Demographic data, surgery-related factors, and radiographic parameters were analyzed. After univariate analysis of factors associated with cage subsidence, multivariate logistic regression was used to identify related factors.

Results: The demographic data showed a significant difference in Hounsfield unit (HU) (102.6±28.3 vs. 80.0±30.6, p=0.005) and endplate injury (p<0.001). Furthermore, 1A1B fixation was significantly more common in the subsidence group (p<0.001). Radiographic data showed significant differences in Δlocal kyphosis (supine-standing) (-7.1°±9.2° vs. -14.6°±11.5°, p=0.001). Multivariate analysis showed that Δlocal kyphosis (supine-standing) (adjusted odds ratio [aOR], 12.8; p=0.010), HU (aOR, 8.1; p=0.033), fixation range (aOR, 8.2; p=0.020), and endplate injury (aOR, 18.8; p=0.011) were significant risk factors for subsidence.

Conclusions: Intraoperative endplate injury, low HU (<87.5), short fusion, and preoperative vertebral instability (Δlocal kyphosis [supinestanding] <-14) were identified as risk factors for cage subsidence in APSF. Therefore, extending the fusion levels in patients with low HU values and significant preoperative vertebral instability should be considered to avoid intraoperative endplate injury.

Study design: Finite element analysis.

Purpose: To investigate the biomechanical response of posterior short-segment fixation with or without intermediate screws at the index vertebra in osteoporotic thoracolumbar burst fractures using finite element analysis.

Overview of literature: Spinal fixation in elderly patients with osteoporotic vertebral fractures is challenging because osteoporosis weakens the screw-bone interface, leading to screw loosening and loss of fracture reduction. Short segment fixation with intermediate screws has been proposed to reduce kyphosis recurrence and implant failure in unstable thoracolumbar fractures. However, the mechanisms by which intermediate screws enhance fixation strength in osteoporotic spines remain unclear.

Methods: Six finite element models of T12 burst fractures were developed to simulate short-segment stabilization under normal or osteoporotic bone conditions, with/without augmentation screws at the fractured vertebra. Spinal stiffness, implant stresses, and axial displacement/micromotion of the bony defect were measured and compared under mechanical loading.

Results: Osteoporotic models exhibited a greater range of motion (ROM) than normal bone. All six-screw constructs reduced ROM across all motions compared with traditional four-screw models. Osteoporotic fracture models gained greater benefit from intermediate screw augmentation at the fracture vertebra, which also lowered axial displacement/micromotion. In six-screw models, rod stress increased while pedicle screw stress decreased. Intermediate screws at fractured vertebrae produced similar changes in stress distribution across all fixation models, regardless of bone quality.

Conclusions: Our findings may facilitate implant selection for osteoporotic burst fractures, supporting the use of more rigid fixation sixscrew constructs to reduce the risk of mechanical failure and postoperative re-collapse.

Study design: Multicenter retrospective cohort study.

Purpose: To evaluate the impact of abscess presence and type on treatment duration and clinical outcomes in patients undergoing minimally invasive posterior fixation for thoracolumbar pyogenic spondylitis.

Overview of literature: Surgical management is increasingly favored for pyogenic spondylitis. Abscesses, particularly epidural and iliopsoas, have been linked to poorer prognoses, and empyema, though uncommon, tends to be particularly severe. However, the effect of specific abscess types on surgical outcomes remains unclear.

Methods: This study included 92 patients who underwent minimally invasive posterior fixation across 10 centers between 2014 and 2024. Patients were classified into an abscess group (epidural, iliopsoas, empyema, or other) and a non-abscess group. Clinical outcomes, including total duration of intravenous antibiotics and unplanned additional surgeries, were compared. Subgroup and regression analyses were conducted to assess the impact of specific abscess type.

Results: Abscesses were present in 65 patients (71%): epidural (n=51), iliopsoas (n=38), and empyema (n=3), with some overlap. Compared with the non-abscess group (n=27; 29%), there were no significant differences in antibiotic duration or rates of unplanned additional surgery. However, iliopsoas abscess was associated with longer antibiotic duration (8.1 weeks vs. 6.6 weeks, p =0.044), while all empyema cases required additional surgery for poor infection control (p =0.000). Regression analysis identified iliopsoas abscess and age ≥65 years as independent predictors of prolonged antibiotic use, whereas epidural abscess was associated with shorter antibiotic duration.

Conclusions: Iliopsoas abscesses were associated with longer antibiotic courses, while empyema was linked to poor infection control and a higher likelihood of additional surgery.

Study design: Retrospective study.

Purpose: To compare postoperative paravertebral muscle atrophy, fat infiltration, and clinical efficacy between unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) and Wiltse approach transforaminal lumbar interbody fusion (W-TLIF).

Overview of literature: The long-term effects of UBE-TLIF and W-TLIF techniques on paravertebral muscle integrity and clinical outcomes have not been directly compared.

Methods: Fifty patients who underwent UBE-TLIF and 50 patients who underwent W-TLIF, each with >2 years of follow-up, were retrospectively analyzed. Outcomes included operative parameters, time to postoperative mobilization, paravertebral muscle atrophy and fat infiltration rates, clinical scores (Visual Analog Scale [VAS], Oswestry Disability Index [ODI], Japanese Orthopaedic Association [JOA]), modified Macnab criteria, fusion rates, and complications.

Results: Compared with W-TLIF, the UBE-TLIF group had significantly less intraoperative blood loss, shorter operative times, and lower postoperative drainage volumes (p <0.05). The UBE-TLIF group showed faster postoperative recovery and shorter hospital stays. At 6 months, 1 year, and 2 years, W-TLIF patients had higher multifidus and erector spinae atrophy, and greater paravertebral muscle fat infiltration (p <0.05). The UBE-TLIF group also had lower VAS and ODI scores at 1 year and 2 years (p <0.05) and fewer surgical complications (6% vs. 10%). Fusion rates (94% vs. 92%) and modified Macnab outcomes (88% vs. 86%) were comparable (p >0.05).

Conclusions: UBE-TLIF is associated with reduced intraoperative trauma, quicker recovery, and fewer complications. In the long-term, it better preserves paravertebral muscle integrity and provides superior pain and functional outcomes.

Study design: Retrospective cohort study.

Purpose: This study aimed to examine outcomes in patients with adult spinal deformity (ASD) undergoing deformity correction with and without glucagon-like peptide-1 receptor agonist (GLP-1A) therapy.

Overview of literature: GLP-1As, widely used in diabetes management, have recently been linked to reduced postoperative complications. However, their role in spinal surgery remains underexplored.

Methods: This multicenter, retrospective cohort study was conducted using the TriNetX Global Collaborative Database (2005-2025) utilizing Current Procedural Terminology and International Classification of Diseases, 10th Revision, codes for patients undergoing spinal deformity correction because of ASD. Patients prescribed GLP-1As within 1 year of surgery were 1:1 propensity-score matched with those who were not using GLP-1As. The cohort was matched according to patient demographics and comorbidities. Surgical outcomes between groups were analyzed at 1- and 2-year intervals. Significance was defined as p <0.05.

Results: At 1 and 2 years following surgery, patients taking GLP-1As exhibited significantly lower odds of pseudoarthrosis, hardware failures, wound dehiscence, infections, thromboembolic events, readmissions, and mortality.

Conclusions: The findings reveal a significant reduction in the rates of pseudoarthrosis, hardware failure, readmission, and mortality in patients treated with GLP-1As. These results align with the recent literature, pointing to a potential complementary therapy in ASD management. Further studies characterizing the mechanism by which GLP-1As affect postoperative spinal physiology are warranted to assess their utility in optimizing patient outcomes.

Study design: Retrospective study.

Purpose: To investigate the diagnostic utility of anterior epidural fat (EF) for distinguishing isthmic from degenerative lumbar spondylolisthesis.

Overview of literature: Isthmic and degenerative lumbar spondylolisthesis must be distinguished accurately for appropriate clinical decision making. However, magnetic resonance imaging (MRI) often fails to detect pars defects; thus, additional imaging markers are needed.

Methods: We retrospectively analyzed lumbar spondylolisthesis in 274 patients, of whom 129 had isthmic disease and 145 had degenerative disease. We assessed the presence and structure of anterior EF on midsagittal MRI, calculated diagnostic performance metrics, and used multivariable logistic regression to identify independent predictors of isthmic spondylolisthesis.

Results: Anterior EF was observed in 95.3% of isthmic cases and 28.3% of degenerative cases (p <0.001). As a diagnostic marker, anterior EF had 95.3% sensitivity and 71.7% specificity, and the area under the receiver operating characteristic curve indicated excellent discriminative ability. Morphologically, acute triangular anterior EF was significantly more common in patients with isthmic disease (75.2%) than in those with degenerative disease (17.2%). Multivariable analysis confirmed anterior EF as a strong independent predictor (odds ratio, 38.730; p <0.001).

Conclusions: Anterior EF is an MRI feature that is highly sensitive and moderately specific for identifying isthmic spondylolisthesis. Its presence and characteristic acute triangular structure are valuable ancillary signs that are useful in early, noninvasive diagnosis.

Study design: Randomized controlled trial with a pretest-posttest control group design.

Purpose: To investigate the radiographic and clinical effects of core stabilization exercises (CSEs) on cervical sagittal alignment and pain in individuals with forward head posture (FHP).

Overview of literature: FHP is a common postural disorder increasingly linked to prolonged screen use. Conventional rehabilitation primarily targets cervical musculature, whereas the role of core stabilization in influencing cervical alignment remains underexplored.

Methods: Forty patients (aged 20-40 years) with FHP (craniovertebral angle ≤50°) were randomly assigned to two groups: group A received CSEs combined with postural correction exercises (PCEs), and group B received PCEs alone. Interventions were delivered 3 times per week for 6 weeks. The primary outcomes were T1 slope (T1S), spino-cranial angle (SCA), and pain intensity measured using the Pain Rating Scale (PRS).

Results: Thirty-six participants completed the intervention. A two-way mixed-design multivariate analysis of variance revealed a significant main effect of time (F =19.461, p <0.001) and a significant time×group interaction (F =9.726, p <0.001), indicating superior improvements in group A. Group A demonstrated significantly greater gains in SCA and PRS scores compared to group B (p <0.05). Both groups showed significant improvements in T1S.

Conclusions: CSEs are effective in improving cervical sagittal alignment and reducing cervical pain in individuals with FHP. These findings support the integration of core-focused interventions into clinical rehabilitation programs for postural dysfunction (ClinicalTrial.gov registration number: NCT06160245).

Study design: Retrospective study.

Purpose: To evaluate the efficacy of a surgical protocol utilizing novel anterior-only reduction and fixation techniques for acute, delayed, and old subaxial cervical facet dislocations.

Overview of literature: There is no clear consensus on the optimal surgical approach (anterior, posterior, or combined) for cervical facet dislocation.

Methods: Over a 10-year period, 87 consecutive patients with subaxial cervical facet dislocations were treated using an anterior-only approach. Patients were classified into three groups: (1) those indicated for urgent surgery; (2) those contraindicated for urgent surgery; and (3) those with old dislocations. Closed reduction was used in patients contraindicated for urgent surgery. Open reduction involved two anterior-only reduction techniques: modified Caspar pin kyphotic paramedian distraction and anterior facetectomy if required. Fixation was performed with anterior vertebral screw plates for C3/4, C4/5, and selected C5/6 cases, or pedicle screw plates for C6/7, C7/ T1, and C5/6 cases with severe vertebral or articular process fractures.

Results: Reduction success rates were 67% for closed reduction, 81% for the modified Caspar pin kyphotic paramedian distraction, and 100% for anterior facetectomy. No supplemental posterior surgery was required. At a minimum follow-up of 12 months, all patients achieved satisfactory fusion without implant failure. Neurological improvement of at least one American Spinal Injury Association grade was observed in 29 patients (43.9%), and no neurological deterioration occurred.

Conclusions: The anterior-only protocol, incorporating modified kyphotic paramedian distraction with Caspar pins, anterior facetectomy, and anterior pedicle screw plate fixation, is safe and effective for managing acute, delayed, and old subaxial cervical facet dislocations.