The value of lateral spread response monitoring in predicting the clinical outcome after microvascular decompression in hemifacial spasm: a prospective study on 100 patients

Abstract

Microvascular decompression represents an effective treatment for hemifacial spasm. The use of lateral spread response (LSR) monitoring remains a useful intraoperative tool to ensure adequate decompression of the facial nerve. The aim of this study was to assess the value of LSRs intraoperative monitoring as a prognostic indicator for the outcome of microvascular decompression in hemifacial spasm. Our study included 100 patients prospectively. The patients were classified into four groups whether LSRs were totally, partially, not relieved, or not detected from the start. According to clinical outcome, the patients were classified into four groups depending on the clinical course after surgery and the residual symptoms if any. Then, correlations were made between LSR events and treatment outcome to detect its reliability as a prognostic indicator. LSRs were relieved totally in 56 % of the patients, partially relieved in 14 %, not relieved in 10 %, and were not detected in 20 % of the patients from the start. HFS was relieved directly after operation in 62 % with clinical improvement of 90-100 %. Thirty-one percent described 50-90 % improvement over the next 3 months after surgery. Almost all of these 31 % (28 out of 31 patients) reported further clinical improvement of 90-100 % within 1 year after surgery. Three percent suffered from a relapse after a HFS-free period, and 4 % reported minimal or no improvement describing 0-50 % of the preoperative state. The percentage of the satisfied patients with the clinical outcome who reported after 1 year a clinical improvement of 90-100 % was 90 %. Statistical analysis did not find a significant correlation between the relief of LSRs and clinical outcome. LSRs may only represent an intraoperative tool to guide for an adequate decompression but failed to represent a reliable prognostic indicator for treatment outcome.

Fully endoscopic microvascular decompression for hemifacial spasm

“…Some studies have found that intraoperative LSR does not correlate with postdecompression outcome in HFS. 6,24,38 Other studies have reported that intraoperative LSR accurately predicts clinical outcome. 19 A meta-analysis showed that if the LSR is abolished intraoperatively, the success rate of achieving symptom relief will be 90.5% but will drop to 61% when the LSR cannot be abolished intraoperatively.…”

Nerve Compression Syndromes in the Posterior Cranial Fossa

“…This pattern of movement cannot be reproduced in persons without the condition (e14). The diagnosis of hemifacial spasm can generally be made immediately on inspection, but it can also be confirmed electrophysiologically by the demonstration of pathological lateral spreading of activation (24). A source of additional distress to persons with this condition is that the facial spasms are often wrongly thought to be psychogenic (e15).…”

Efficacy and Complications of Microsurgical Neurovascular Decompression in 55 Patients With Hemifacial Spasm

“…18,33 No intraoperative monitoring of the facial nerve was used in our study, as it makes surgery more difficult and limits its reliability. 19,34 The signal characterizing the spasm may indeed disappear while HFS persists when the patient wakes up. 35 Otherwise, monitoring increases morbidity by unnecessary surgical procedures.…”