Patient-specific Factors Predict Outcomes of Anterior Vertebral Body Tethering in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis

Introduction: Anterior vertebral body tethering (AVBT) is a non-fusion technique for correcting adolescent idiopathic scoliosis (AIS) that preserves spinal motion by applying the Hueter-Volkmann principle. Patient factors such as preoperative Cobb angle, skeletal maturity, and age may influence the effectiveness and complication rates of AVBT. This systematic review and meta-analysis aims to identify key patient-specific predictors of successful outcomes and complications in AVBT for AIS.

Methods: A literature search was conducted in PubMed, Web of Science, Embase, Scopus, and CENTRAL up to April 2024, following PRISMA guidelines (PROSPERO ID:528011). Studies on AVBT for AIS evaluating indications, outcomes, complications, and revisions were included. Extracted data encompassed patient demographics, patient-specific factors (Risser score, Sanders classification), surgical details, and outcomes. Quantitative analyses were performed using weighted averages and random-effects meta-analysis. Statistical tests included independent t-tests, one-way ANOVA, chi-square tests, correlation analyses, and multivariate regression models.

Results: Thirty-three studies comprising 2,083 patients were included. The mean weighted age was 13.0±1.1 years, with 84.6% being female. The weighted median Risser score was 1 [IQR: 0-3], and the median Sanders classification was 3 [2-5]. The mean preoperative Cobb angle was 50.0±4.8 degrees, reduced to 25.0±4.5 degrees postoperatively (p < 0.0001), and further improved to 22.1±4.7 degrees at last follow-up (p < 0.0001). The weighted average complication rate was 17.2%±7.7%, and the revision rate was 10.1%±7.4%. Complication rates negatively correlated with age (r=–0.30, p=0.005) and female sex (r=–0.34, p=0.001), and positively correlated with revision rates (r=0.76, p< 0.0001). Multivariate regression identified higher preoperative Cobb angle (OR=2.64, p=0.002) and lower Risser score (OR=0.09, p=0.006) as significant predictors of higher postoperative Cobb angle.

Conclusion : Lower preoperative Cobb angle, skeletal maturity, and female sex are significant predictors of successful outcomes in AVBT for AIS. Recognizing these factors can enhance surgical planning and patient selection, potentially improving outcomes and reducing complications associated with AVBT.