Evaluation of 2 Surgical Techniques-Transposition Versus Interposition Microvascular Decompression for Hemifacial Spasm: A Systematic Review of 19 437 Patients.

Abstract

Background and objectives: Hemifacial spasm (HFS) is a rare movement disorder characterized by brisk, irregular, involuntary, and unilateral contraction of the facial musculature. This systematic review aims to synthesize the existing literature and compare the use of 2 microvascular decompression (MVD) techniques-transposition and interposition-used in the treatment of HFS.

Methods: A retrospective systematic review of randomized controlled trials, meta-analyses, case-control studies, and case series examining transposition and/or interposition during MVD for HFS was performed using PubMed, Embase, and Scopus databases. Data extracted included study objective and size, surgical method, demographic information, operative technique notes, number and location of offending vessels, complications, follow-up duration, rate of spasm freedom at last follow-up, and additional outcomes. Cohorts of at least 20 patients with HFS treated with MVD reported in studies explicitly mentioning surgical techniques were included.

Results: PubMed, Embase, and Scopus database searches yielded 1300 records, of which 528 were duplicates. Sixty-two studies reporting 68 cohorts met inclusion criteria, including 5 on transposition, 51 on interposition, and 6 using both techniques. Interposition was used in 18 627 cases, and transposition was used in 810 cases. Spasm freedom at final follow-up was similar between transposition and interposition (90.4% vs 89.6%). Complication rates were similar between techniques, with the largest difference being higher rates of temporary facial nerve weakness/palsy among the transposition series (9.52%) than the interposition series (6.03%).

Conclusion: Both transposition and interposition are safe and effective techniques for MVD in patients with HFS. Available literature to date does not provide conclusive evidence that 1 method is superior to the other in safety or efficacy although there are specific instances that favor the use of interposition. A prospective trial would be required to delineate the true differences between these techniques.