Prognostic Factors for Outcome of Fusion Surgery in Patients With Chronic Low Back Pain - A Systematic Review.

Study design: Systematic review.

Objective: This systematic review aims to identify prognostic factors, encompassing biomedical and psychosocial variables, linked to outcome of fusion surgery for chronic low back pain (CLBP) in single or two-level lumbar degenerative spinal disorders. Identifying these factors is crucial for decision making and therefore long-term treatment outcome.

Methods: A systematic search (PROSPERO ID: CRD4202018927) from January 2010 to October 2022 was conducted, utilizing Medline, Embase, and the Cochrane Database of Systematic Reviews (CDSR, CENTRAL). Prognostic factors associated with various outcomes, including functional status, back and leg pain, health-related quality of life, complications, return to work, and analgesic use, were assessed. Risk of bias was determined using QUIPS, and the quality of evidence was evaluated using GRADE approach.

Results: Of the 9852 initially screened studies, eleven studies (n = 16,482) were included in the analysis. In total, 161 associations were identified, with 67 prognostic factors showing statistical significance (P < 0.05). Thirty associations were supported by two or more studies, and only eight associations were eligible for meta-analyses: female gender remained statistically significant associated with decreased postoperative back pain, but negatively associated with complication rates and functional status, and smoking with increased postoperative back pain.

Conclusion: Only female gender and smoking were consistently associated with outcome of fusion for CLBP. Most of the included studies exhibited low to moderate methodological quality, which may explain the relatively weak associations identified for the assessed prognostic factors.