Abstract
BACKGROUND: Endoscopic lumbar fusion has emerged as a minimally invasive alternative to traditional open fusion, yet large-scale comparative evidence on postoperative safety and long-term effectiveness remains limited. This study evaluated national real-world outcomes following endoscopic versus open lumbar fusion. METHODS: A retrospective cohort study was performed using the TriNetX US Collaborative Network. Adult patients undergoing endoscopic and open lumbar fusion were identified using ICD-10-PCS codes. Propensity score matching (1:1) generated 2 balanced cohorts (n=23,723 each). Ninety-day medical and surgical complications were compared using odds ratios (ORs) with 95% confidence intervals (CIs). One-year and 2-year pseudoarthrosis, instrumentation failure, and revision surgery were evaluated using risk ratios (RRs) with 95% CIs. Statistical significance was set at p<.05. RESULTS: Endoscopic fusion demonstrated higher 90-day rates of UTI (OR: 1.20, 95% CI, 1.06-1.35, p=.003) and pneumonia (OR: 1.22, 95% CI, 1.01-1.47, p=.043). Among surgical outcomes, endoscopic fusion had higher post-operative hematoma (OR: 1.42, 95% CI, 1.05-1.92, p=.023) and SSI (OR: 1.36, 95% CI, 1.20-1.54, p<.001), but lower wound complications (OR: 0.94, 95% CI, 0.79-1.11, p=.461) and CSF leak (OR: 0.59, 95% CI, 0.45-0.78, p<.001). At one year, endoscopic fusion showed higher pseudoarthrosis (13.5% vs. 6.4%, RR: 2.10, 95% CI, 1.99-2.22, p<.001), whereas rates of revision surgery were not significantly different (0.70% vs. 0.62%, RR: 1.14, 95% CI, 0.92-1.40, p=.231). Instrumentation failure remained lower (0.09% vs. 0.30%, RR: 0.31, 95% CI, 0.19-0.49, p<.001). At 2 years, pseudoarthrosis (18.9% vs. 8.8%, p<.001) remained higher, instrumentation failure remained lower (0.2% vs. 0.65%, p<.001), and revision surgery occurred at similar rates (1.60% vs. 1.60%, p=.994). CONCLUSIONS: Endoscopic lumbar fusion was associated with higher rates of several medical and infection-related complications, as well as significantly higher pseudoarthrosis at 1 and 2 years, while demonstrating lower instrumentation failure. These findings highlight distinct risk profiles between techniques and emphasize the importance of patient selection and continued refinement of endoscopic fusion approaches.