Characteristics and Risk Factors of Rod Fracture Following Adult Spinal Deformity Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE: The aim of study is to investigate the features and risk factors of rod fracture (RF) following adult spinal deformity (ASD) surgery. METHODS: We searched the PubMed, Embase, Web of Science, and Cochrane Library databases to identify relevant studies. Patient’s data including age, sex, body mass index (BMI), previous spine surgery, pedicle subtraction osteotomy (PSO), interbody fusion, fusion to the pelvis, smoking history, preoperative sagittal vertical axis (SVA), preoperative pelvic tilt (PT), preoperative pelvic incidence minus lumbar lordosis, preoperative thoracic kyphosis (TK), and change in the SVA were documented. Comparable factors were evaluated using odds ratio (OR) and weighted mean difference (WMD) with 95% confidence interval (CI). RESULTS: Seven studies were included. The overall incidence of RF following ASD surgery was 12%. Advanced age (WMD, 2.8; 95% CI, 1.01–4.59; p<0.002), higher BMI (WMD, 1.98; 95% CI, 0.65–3.31; p=0.004), previous spine surgery (OR, 1.47; 95% CI, 1.05–2.04; p=0.02), PSO (OR, 2.28; 95% CI, 1.62–3.19; p<0.0001), a larger preoperative PT (WMD, 6.17; 95% CI, 3.55–8.97; p<0.00001), and a larger preoperative TK (WMD, 5.19; 95% CI, 1.41–8.98; p=0.007) were identified as risk factors for incidence of RF. CONCLUSION: The incidence of RF in patients following ASD surgery was 12%. Advanced age, higher BMI, previous spine surgery, and PSO were significantly associated with an increased occurrence of RF. A larger preoperative PT and TK were also identified as risk factors for occurrence of RF following ASD surgery.