Which surgical technique has a superior clinical outcome in microvascular decompression? a systematic review and meta-analysis study of transposition versus interposition for trigeminal neuralgia and hemifacial spasm.

Microvascular decompression (MVD) remains the most effective treatment for managing trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia. Despite variations in technique, the clinical outcomes of transposition and interposition for MVD have shown mixed results. Here, we use a meta-analysis approach to evaluate the clinical outcomes of transposition versus interposition techniques for trigeminal neuralgia and hemifacial spasm. We systematically retrieved articles published before August 31, 2024, from PubMed, the Cochrane Library Database, and Web of Science. Our analysis included 9 studies encompassing 1,392 patients. We found that transposition was performed more frequently (58.8%) than interposition (42.2%). Both techniques exhibited comparable clinical outcomes for early spasm resolution (92.81% vs. 86.64%; OR [odd ratio] = 1.09; 95% CI [confidence interval], 0.27-4.37; p = 0.907), recurrence rates (5.57% vs. 6.34%; OR = 0.71; 95% CI, 0.32-1.60; p = 0.410), and overall postoperative complications (12.24% vs. 12.93%; OR = 1.01; 95% CI, 0.67-1.54; p = 0.951). Transposition demonstrated superior postoperative total resolution compared to interposition (90.17% vs. 86.25%; OR = 2.14; 95% CI, 1.48-3.11; p < 0.001). A subgroup analysis demonstrated that this superior postoperative total resolution only found in hemifacial spasm (96.73% vs. 90.90%; OR = 3.54; 95% CI, 1.78-7.07; p < 0.001) but not in trigeminal neuralgia (83.38% vs. 77.42%; OR = 1.77; 95% CI, 0.72-4.37; p = 0.213). In conclusion, this meta-analysis demonstrates that both techniques show comparable clinical outcome in early spasm resolution, recurrence rate, and postoperative complications, but transposition achieves superior postoperative total resolution outcomes. These findings suggest that transposition is a preferable approach whenever possible, i.e., in patients with hemifacial spasm, while interposition remains a reliable alternative.