Clinical Study Of Neuroelectrophysiological Monitoring In Microvascular Decompression Of Hemifacial Spasm

Objectives:To analyze the guiding significance and value of neuroelectro-physiological monitoring in facial nerve microvascular decompression and its value in evaluating surgical outcome.Methods:Retrospective analysis of 72 patients with primary hemifacial spasm treated with microvascular decompression in the Department of Neurosurgery,First Affiliated Hospital of Kunming Medical University from September 2016 to January 2018.Among them,32 cases underwent intraoperative LSR monitoring,and 40 cases were not monitored during operation.All cases underwent 3D-TOF-MRA to identify the responsible vessels before surgery,and excluded secondary hemifacial spasm,and performed mirovascular decompression by the same group of surgeons.Patients were immediately followed up after surgery and they were followed up after 6 months and 1 year of surgery.Patients were followed up to observe their complications,such as facial paralysis and hearing impairment,after 3 days,1 month and 1 year of surgery,and the significance of the changes of LSR during microvascular decompression was analyzed.Results:32 patients who underwent LSR monitoring,LSR waves were extracted before the operation began.In 22 cases,the LSR disappeared after decompression with the polyester pad,and the LSR never appeared anymore when the stimulation was increased.In 2 cases,the LSR waves reappeared after decompression with the polyester pad,after the facial nerve was explored,the responsible vessels were found to be missed,the waves disappeared with adjusting the position of the polyester pad.In 4 cases,the LSR disappeared after cutting the meninges and separating the surrounding arachnoid,and never reappeared after decompression.In 2 cases,the vessels were fully decompressed before the skull was closed,but the waveforms reappeared when the normal saline was injected into the cranial cavity,the polyester pad was found to be moved its position after exploration,and then the abnormal LSR waves disappeared after adjusting the position of the polyester pad.In 1 case,the LSR waves still existed after suturing the meninges but the LSR amplitude decreased significantly(>50%).In 1 case,the continuous and typical LSR waves were still monitored after the skull was closed.(1)Immediate postoperative outcome:In the test group,the effective rate was 93.8%(30/32).In the control group,the effective rate was 75.0%(30/40).The statistical analysis results P<0.05(P=0.034),so this indicates a statistical difference between the test group and the control group,so the test group is more efficient than the control group;(2)6 months after surgery:In the test group,the effective rate was 96.6%(31/32).In the control group,the effective rate was 85.0%(34/40).The statistical analysis results P>0.05(P=0.091),there is no statistical difference between the experimental group and the control group,so the test group is not more efficient than the control group;(3)1 year after surgery:In the test group,the effective rate was 96.6%(31/32).In the control group,the effective rate was 87.5%(35/40).The statistical analysis results,P>0.05(P=0.153),there is no statistical difference between the experimental group and the control group,so the test group is not more efficient than the control group.(4)In the test group,the incidence rate of complications was 3.1%(1/32),and in the control group,the incidence rate of complications was 20%(8/40).The statistical analysis results P<0.05(P=0.031),so this indicates a statistical difference between the test group and the control groupConclusions:Intraoperative LSR monitoring,the disappearance of LSR waves is helpful for finding responsible vessels and judging whether the vessels are fully decompressed in MVD.And there are certain reference values for predicting the short-term efficacy.But there is no reference value for predicting the long-term efficacy,and it can not be the only one indicator to predict the efficacy,because of the existence of the delayed resolution and it can influence the prediction results.The disappearance of LSR waves is helpful for finding responsible vessels,so over-drawing of the facial nerve and the auditory nerve can be avoided,and then the complications were reduced.