Endoscopic surgery for multilevel spinal stenosis: a comprehensive meta-analysis and subgroup analysis of uniportal and biportal approaches.

Minimally invasive spine surgery (MIS) has shown promising results, and endoscopic spine surgery has emerged as a less invasive approach. Although studies have examined the effectiveness of endoscopic surgery for spinal stenosis, no meta-analyses have focused on multilevel cases. This meta-analysis aimed to evaluate the efficacy and safety of uniportal and biportal endoscopy in patients with multilevel spinal stenosis. The patient, intervention, comparison, outcomes, and study criteria were established to guide study selection. Four databases were searched. The outcome measures included patient-reported outcome measures (PROMs), radiological and analytical data, complications, surgery time, length of hospital stay, and blood loss. Review Manager ver. 5.4 software (RevMan; Cochrane, UK) was used for the analysis. Heterogeneity was assessed using the chi-square and I2 tests. Ten studies (n=686) were included. PROMs showed significant improvements in Visual Analog Scale (VAS) scores for back pain (mean difference [MD], 4.07; 95% confidence intervals [CI], 3.72-4.42), leg pain (MD, 5.49; 95% CI, 5.17-5.80), and Oswestry Disability Index (MD, 35.97; 95% CI, 32.46-39.47). MacNab scale results were as follows: excellent (55.37%), good (34.93%), fair (7.58%), and poor (4.06%). C-reactive protein levels did not change significantly; however, hemoglobin levels decreased postoperatively (MD, 1.28; 95% CI, 0.91-1.65). Complications included dural tears (5.46%), hematoma (4.30%), incomplete decompression (3.12%), root injury (2.90%), reoperations/revisions (2.22%), conversion to open or microscopic surgery (1.97%), and transfusions (8.50%). Analysis by levels showed worse VAS leg pain in studies analyzing >30% multilevel stenosis (MD, 4.99; 95% CI, 4.47-5.51 vs. MD, 5.82; 95% CI, 5.63-6.01). Uniportal and biportal endoscopy had similar outcomes, except for a higher incidence of dural tears on biportal endoscopy (uniportal, 3.33%; biportal, 7.05%). This meta-analysis supports endoscopy as an effective and safe option for multilevel lumbar stenoses. It improves long-term pain and functionality, with no significant radiological changes or postoperative inflammation. Complications are few; however, dural tears are more common in biportal endoscopy. Higher multilevel stenosis rates were associated with increased leg pain and a lower likelihood of achieving incomplete decompression.