Retrospective study of the combined application of the blink reflex and lateral spread reflex in microvascular decompression of facial nerve surgery.

BACKGROUND: The blink reflex (BR) can be used as a routine monitoring method during facial nerve microvascular decompression. This study aimed to investigate whether the use of the BR in hemifacial spasm (HFS) surgery is comparable to that of the lateral spread reflex (LSR), and to explore its significance for guiding intraoperative neurophysiological monitoring (IONM). METHODS: Patients undergoing facial nerve microvascular decompression from 2016 to 2018 were included in the study. According to the results of IONM, the intraoperative monitoring items of the BR and two conventional facial nerve microvascular decompression procedures, namely the marginal mandibular branch LSR (MAR-LSR) and zygomatic branch LSR (ZYG-LSR), were compared. We mainly compared whether there were differences in the occurrence rate, disappearance rate, waveform, occurrence current, and prognosis of the three monitoring methods. RESULTS: The occurrence rate of the BR was lower than that of the MAR-LSR and ZYG-LSR, as well as the three combined detection groups. The disappearance rate of the BR was not different to that of the MAR-LSR, but higher than that of the ZYG-LSR group. In addition, the waveform of the BR showed differences from that of the MAR-LSR and ZYG-LSR. The incidence of postoperative residual symptoms in patients with any kind of reflex on the first day after surgery and the day of discharge was significantly higher than that of patients in which all three reflexes disappeared. CONCLUSIONS: Combined BR and LSR monitoring can reduce the occurrence of postoperative residual symptoms. We suggest that by increasing the use of BR examination during surgery, the integrity of the trigeminal nerve can be protected.

Feasibility of using surface electromyography for the detection of abnormal muscle response in patients with hemifacial spasm / 西安交通大学学报(医学版)

【Objective】 To investigate the feasibility of using surface electromyography （SEMG） for the detection of abnormal muscle response （AMR） in patients with hemifacial spasm （HFS）. 【Methods】 We retrospectively reviewed the clinical data of HFS patients who underwent microvascular decompression （MVD） in our hospital between June 2019 and December 2020. Patients who received both surface electrode （preoperative） and needle electrode （intraoperative） detection of AMR were included. SEMG recorded from two stimulation-recording sites， namely， zygomatic-mentalis and mandibular marginal-orbicularis oculi， was selected for analyzing the characteristics of AMR. The positive rates of AMR detected by these two kinds of electrodes were comprehensively compared. 【Results】 Totally 77 patients were included in this study. When detected with surface electrodes， the positive rate， latency and amplitude of AMR recorded at zygomatic-mentalis oculi were 90.9% （70/77）， （10.87±1.86） ms and （202.8±47.4） μV， and at mandibular marginal-orbicularis oculi were 92.2% （71/77）， （10.41±1.83） ms and （211.1±54.1） μV， respectively. AMR was detected in 74 patients （96.1%） with surface electrodes. There was no significant difference in positive rate， latency and amplitude of AMR between these two stimulation-recording methods. When detected with needle electrodes， the positive rate of AMR recorded at zygomatic-mentalis oculi was 98.7% （76/77）， which was significantly higher than the rate 89.6% （69/77） recorded at mandibular marginal-orbicularis oculi （P=0.016）. The latency and amplitude of AMR recorded at zygomatic-mentalis were （10.63±1.39） ms and （83.5±27.2） μV， and at mandibular marginal-orbicularis oculi were （10.31±1.18） ms and （58.6±21.4） μV. There was no significant difference in latency between the two stimulation-recording methods， but the amplitude recorded at mandibular marginal-orbicularis oculi was significantly lower （P=0.041）. AMR was detected in 76 patients （98.7%） with needle electrodes. There was no significant difference in the detection rate of AMR between surface electrodes and needle electrodes （P=0.500）， the results were moderately consistent （Kappa=0.490， P<0.001）. 【Conclusion】 The detection efficiency of surface electrodes for AMR is similar to that of needle electrode. With its non-invasive characteristic， the surface electrode can be routinely used for electrophysiological evaluation of HFS.

Clinical analysis of microvascular decompression in patients with hemifacial spasm: a retrospective study.

BACKGROUND: Unilateral contractions of the facial muscles characterize hemifacial spasm (HFS). Microvascular decompression (MVD) was widely accepted for the treatment of HFS. To investigate the operative effects and surgical complications in patients with HFS after MVD. METHODS: A retrospective analysis of 540 patients with HFS after MVD was conducted from January 2017 to May 2018. All patients were followed up for 2 years on average. Surgical effects were evaluated on the patients' manifestations according to the Cohen score classification. RESULTS: During the follow-up period, 455 patients (84.26%) were completely cured, 60 patients (11.11%) were partial relief, 25 patients (4.63%) were failed cure. The effective rate was 93.52% on the first day after MVD, and 95.37% on the follow-up period. Ten patients (1.85%) were facial paralysis (FP) on the 1st day of post-operation. Twenty-five patients (4.63%), FP; the patients with delayed facial palsy were all completely cured in 3 months. Fourteen patients (2.59%) were hearing deficit after MVD, in whom 8 patients (1.48%) had good improvement, and 6 patients (1.11%) had no changes. There was no recurrence case or death case recorded. CONCLUSIONS: MVD is the best treatment choice that offers the prospect of a definitive cure for HFS. Skilled microsurgical techniques, as well as identifying and sufficiently decompressing offending vessels, are the key to ensuring a safe and successful MVD. Complications of this surgery are uncommon and transient.

AMR monitoring in microvascular decompression for hemifacial spasm: 115 cases report.

In MVD operations assisted by AMR monitoring, the reliability and validity of decompression can be evaluated by observing whether AMR disappears. Although intraoperative AMR monitoring has been used widely, debate exists over its reliability and positive contribution. In this series, 115 cases of HFS treated with MVD operations with AMR monitoring were enrolled. All MVD procedures were performed via a suboccipital retrosigmoid approach. Microscope and endoscope were used alternately as was needed. Medtronic Nim-eclipse system was used for intra-operative AMR monitoring. The zygomatic branch of the facial nerve was stimulated and AMRs were recorded form the mentalis muscle. In 112 of the 115 cases, AMR was recorded during operation. In the 112 cases with typical AMR, AMR disappeared in 105 cases. Among the 105 cases, 79 achieved immediate cure after operation, 21 were spasm-free within 6-month follow-up, and the symptom of 5 cases persisted at 6-month follow-up. Among the 7 cases whose AMR did not disappear at the end of operation, 2 cases achieved immediate cure and 2 cases achieved delayed relief. For those cases with electrophysiological relief, the overall relief rate was 95.2% (100/105); for those with persistent AMR, the overall relief rate was 57.1% (4/7, P < 0.05). In conclusion, AMR monitoring provide valuable information to MVD operation for HFS. The use and investigation of AMR will undoubtedly contribute to the understanding and curing of HFS.