Abstract
Objectives During microvascular decompression (MVD) of the facial nerve for hemifacial spasm
(HFS), an abnormal muscle response can be recorded upon stimulation of the facial
nerve, also known as the lateral spread response. This response may vanish after MVD
and has been associated with a successful outcome. The purpose of this study was to
determine if resolution of lateral spread correlated with the elimination of HFS in
a single surgeon's experience.
Design and Setting (1) Retrospective analysis of 38 patients undergoing MVD with intraoperative electromyography
for HFS. (2) Meta-analysis of studies from the literature.
Main Outcome Measure Presence or absence of HFS and any complications.
Results Lateral spread response was seen in 36 patients; 20 patients had full resolution.
Of these, 15 patients became HFS free, and 5 five patients still had some degree of
HFS. Sixteen patients had a persistent lateral spread response despite a technically
successful MVD; 11 of these became spasm free, and 5 still suffered from some degree
of facial twitching. Analyzing 16 studies reporting a total of 1301 patients, a significant
correlation (p < 0.0001) between response cessation and resolution of HFS was found.
Conclusion The role of monitoring lateral spread response as a predictor for clinical outcome
is limited.
Keywords
hemifacial spasm - intraoperative monitoring - microvascular decompression - lateral
spread response
