Sacroiliac Joint Degeneration Following Lumbar Fusion: What are the Risk Factors?

Purpose: This study aims to identify risk factors and changes in spino-pelvic parameters associated with Sacroiliac (SI) joint degeneration.Materials and Methods: This multicenter retrospective study included 472 patients who underwent fusion surgery at three hospitals between March 2021 and February 2024. SI joint degeneration was assessed using seven indicators: sclerotic changes, erosion, osteophyte formation, intra-articular bone formation, joint space narrowing, intra-articular gas formation, and subchondral cysts. CT scans were performed preoperatively and 6 months postoperatively. The patients were divided into two groups: those with progression of SI joint degeneration and those without. Standing whole spine lateral X-rays were used to measure a total of 10 spinopelvic parameters both preoperatively and at 6 months postoperatively. Statistical analysis was performed using two-sample t-tests and multivariable logistic regression.Results: Among the 472 patients, 135 (28.6%) showed progression of SI joint degeneration. When comparing the two groups, age (p=0.022), alcohol consumption (p=0.001), smoking (p<0.001), and S1 involvement (p=.04) were associated with SI joint degeneration. Regarding spino-pelvic parameters, patients with SI joint degeneration exhibited significant changes in thoracic kyphosis (p=0.017) and pelvic tilt (p=0.049).Conclusions: Sacrum fixation, smoking, alcohol consumption, and age can be significant risk factors for SIJ degeneration following lumbar fusion surgery.