Hemifacial spasm and microvascular decompression:

What we know and what we don’t know

 

Kwan Park, M.D., Ph.D., Kyung-Il Jo, M.D., Jeong A Lee, M.S

 

Abstract

INTRODUCTION: The purpose of this study is to clarify the range and limit of our knowledge of hemifacial spasm(HFS) and microvascular decompression(MVD) with experiences of over 1,600 operative cases.

METHODS: From April 1997 to Febraury 2011, over 1,600 consecutive patients underwent MVD for HFS. Among them, 1,507 patients who underwent MVD for HFS with a minimum 6 months follow-up were enrolled in the study. The median follow-up period was 1.44 years (ranging from 6months to 9.5years). In this study, 1075 (71.3%) patients were women and 432 (28.7%) were men with a mean age of 47.7 years (range 19-77 years). Preoperative imaging studies including magnetic resonance images were performed. Electromyography and brain stem evoked potential were monitored intraoperatively and audiologic studies were conducted in every cases pre- and post-operatively. The Kaplan–Meier method was used to estimate the overall cure rate by SPSS software.

RESULTS: At the last follow-up examination 1,424 (94.5%) patients of total 1,507 patients exhibited the curable state, and 83 (5.5%) patients showed remained spasm(n=68) including recurrences(n=15). Lateral spread response and severity of indentation were associated with favorable outcome. The major postoperative complications included permanent hearing loss in 15 (1.0%), permanent facial palsy in 10 (0.7%), cerebrospinal fluid leak in five (0.33%), and cerebellar infarction or hemorrhage in two (0.13%), and no operative mortality. We published several related issues about pathogenesis, diagnosis, operative procedures and findings, complications and prognosis. Many issues regarding clinical grading systems, neurovascular compressive patterns, prognostic factors, hearing loss, delayed cranial nerve palsies, dural closure technique, safety in the elderly patients were clarified but still some issues about epidemiology, genetics and pathophysiology are to be answered.   

CONCLUSION: MVD is a very effective, safe modality of treatment for HFS. Many issues of HFS and MVD about pathogenesis, diagnosis, operative procedures and prognosis were clarified. But we need further investigations about epidemiology, genetics and pathophysiology to make the MVD a perfect surgery.  

 

KEY WORD: Hemifacial spasm, Microvascular decompression, Complication, Prognosis