Endoscope-assisted decompression of facial nerve for treatment of hemifacial spasm

Microvascular decompression using a fully transcranial neuroendoscopic approach

OBJECTIVE

To evaluate the effectiveness and safety of microvascular decompression (MVD) using a fully transcranial neuroendoscopic approach.

METHODS

Thirty-one patients who underwent MVD using a fully transcranial neuroendoscopic approach in our department between May 2016 and September 2019 were retrospectively reviewed.

RESULTS

All patients successfully underwent MVD, and immediate pain relief was achieved in all 17 cases of trigeminal neuralgia (TGH) and 3 cases of glossopharyngeal neuralgia (GPN). Hemifacial spasm (HFS) was completely resolved in all 11 patients. No mortality or permanent complication was seen.

CONCLUSIONS

The endoscope is a useful tool for confirming vascular conflict identified by the microscope and is helpful in detecting the vessel responsible for neuralgia without retracting the brain and nerves. MVD using a fully transcranial neuroendoscopic approach is an effective and safe alternative to endoscopic-assisted MVD and traditional MVD.

Association study of the pneumatization degree of mastoid air cells and postoperative complications after microvascular decompression in hemifacial spasm

BACKGROUND

This study aimed to analyse the association between the degree of pneumatization of mastoid air cells (MACs) and postoperative complications after microvascular decompression in hemifacial spasm.

METHODS

We retrospectively reviewed 308 patients with hemifacial spasm who underwent surgery at our institute between January 2017 and March 2021. The degree of pneumatization of MACs was classified into four grades (grades 1, 2, 3, and 4) according to method of Han et al. The clinical data of the four grades were analysed and statistically examined.

RESULTS

There were no statistically significant differences between the four grades in terms of the operative time, intraoperative blood loss, and postoperative hospital stay (all, P > 0.05). The incidence of hearing loss was higher in grade 4 MACs (26.56%) than in grades 1 and 2 MACs (5.41% and 2.89%, respectively; P < 0.05). The incidence of facial paralysis was higher in grade 4 MACs (28.13%) than in grades 1 and 2 MACs (5.41% and 9.18%, respectively; P < 0.001). The incidence of intracranial infection was higher in grade 3 MACs (17.65%) than in grade 2 MACs (3.89%) (P < 0.05). All four patients with cerebrospinal fluid leakage belonged to grade 4 MACs. The incidence of cerebrospinal fluid leakage was higher in grade 4 MACs (5.13%) than in grade 2 MACs (P < 0.05).

CONCLUSIONS

This study found that the degree of pneumatization of MACs was closely related to the postoperative complications after MVD surgeries. Well-pneumatized MACs increase the risk of cerebrospinal fluid leakage and intracranial infection. However, insufficient exposure increases the risk of facial paralysis and hearing loss. For patients with well-pneumatized MACs, sufficient surgical exposure is the top priority when locating the bone hole. For those who may have a latent MAC opening, preventive occlusion should be considered.

Usefulness of endoscope-assisted surgery under exoscopic view in skull base surgery: A technical note

Background:

The use of the exoscope has been increasing in the field of neurosurgery, as it can set the visual axis freely, enabling the surgeon to operate in a comfortable posture. Although endoscope-assisted surgery for compensation of insufficient surgical field is useful under the microscope, we report that using an endoscope in exoscopic surgery is safer and more useful.

Methods:

The exoscope used was ORBEYE. All surgical procedures were performed exoscopically from the beginning of the surgery. When endoscopic observation was required during the operation, the endoscope was inserted under observation by an exoscope. The exoscopic screen was 4K-3D and endoscopic screen was 4K-2D, the operation was performed while observing both screens at the same time. The endoscope was held manually or by a mechanical holder.

Results:

Twenty-two cases, including 14 requiring microvascular decompression (MVD) and eight requiring tumor removal, were performed by endoscopic-assisted exoscopic surgery. The endoscope could be inserted safely because its relationship with the surrounding structure could be observed under the exoscope, and the operator could observe both screens without moving the head. Fourteen of 22 patients required additional endoscopic treatment. Satisfactory two-handed operation was performed in 13 cases. Symptomatology disappeared in all cases of MVD, and sufficient tumor resection was achieved.

Conclusion:

Exoscopic surgery provides excellent surgical view that is not inferior to conventional microsurgery. As a large space can be secured between the scope and the surgical field, it is safer and easier to manipulate the endoscope under the exoscope.

Fully endoscopic versus microscopic vascular decompression for hemifacial spasm: a retrospective cohort study

INTRODUCTION

Microvascular decompression (MVD) is the preferred surgical method for hemifacial spasm (HFS). The purpose of this study was to analyze the effectiveness and safety of fully endoscopic MVD for HFS relative to microscopic MVD.

MATERIAL AND METHODS

The retrospective study was conducted on HFS patients who underwent microscopic or fully endoscopic MVD from January 2018 to March 2019. All patients were treated at a single institution and by a single surgeon. Patients were divided into two groups based on the surgical method, and clinical data were then compared between groups.

RESULTS

A total of 116 patients, including 54 cases who received fully endoscopic MVD (E group) and 62 cases who received microscopic MVD (M group), were included in this study. Follow-up efficacy did not differ significantly between groups, with total effective rates of 88.9% in the E group and 90.3% in the M group. When postoperative complications were compared individually, there were no statistically significant differences between the two groups; however, the E group had a higher total incidence of complications than the M group (48.1% vs. 29.0%, P = 0.034).

CONCLUSION

Although both fully endoscopic and microscopic MVD for HFS achieved good efficacy, the former method had a higher total incidence of complications. Based on the results of this study, there is no evidence that a microscope can be replaced by a full endoscope in MVD for HFS.

Feasibility of underwater microvascular decompression for hemifacial spasm: a technical note

BACKGROUND

We present a case series of underwater microvascular decompression (MVD) for hemifacial spasm (HFS) and an evaluation of its feasibility and safety.

METHODS

This retrospective study was conducted at a single institution and included 20 patients with HFS who underwent underwater MVD between September 2019 and January 2021. Surgery was performed in 3 steps, as follows: exoscopic wound opening (soft tissue, bone, dura, and arachnoid around the cerebellomedullary cistern), underwater endoscopic surgery (decompression of the facial nerve), and exoscopic wound closure. In underwater endoscopic surgery, the surgical field was continuously irrigated with artificial cerebrospinal fluid. Abnormal muscle response and brainstem auditory evoked potentials (BAEPs) were monitored.

RESULTS

Neurovascular conflicts were clearly observed in all patients without fogging and soiling of the endoscope lens. HFS was completely relieved in 19 patients (95%). An amplitude reduction of wave V of BAEPs of more than 50% was not observed in any of the cases. In 5 cases (25%), the latency of wave V of BAEPs was prolonged for more than 1.0 ms; these changes completely or near completely returned to baseline values at dural closure in all 5 cases. A postoperative complication of transient facial palsy was observed in 1 patient (5%) during postoperative days 10-30. There were no other complications.

CONCLUSIONS

Our findings suggest that underwater MVD is a safe and feasible option for the treatment of HFS. However, it did not show advantages over conventional endoscopic MVD when the protective effect on the eighth cranial nerve was evaluated.

Fully endoscopic microvascular decompression of the hemifacial spasm: our experience

PURPOSE

Microvascular decompression (MVD) surgery has been accepted as a potentially curative method for hemifacial spasm (HFS). The primary cause of failure of MVD is incomplete decompression of the offending vessel due to inadequate visualization. This study is aimed at evaluating the benefit of endoscopic visualization and the value of fully endoscopic MVD.

METHODS

From March 2016 to March 2018, 45 HFS patients underwent fully endoscopic MVD in our department. From opening the dura to preparing to close, the assistant held the endoscope and the surgeon operated. Abnormal muscle response (AMR) and brainstem auditory evoked potentials (BAEP) were monitored. For every patient, the offending vessel was transposed or interposed and achieved complete decompression. AMR was used to evaluate the adequacy of decompression at the end of the surgery. The intra-operative findings and postoperative outcomes and complications were analyzed.

RESULTS

Immediately after surgeries, 39 patients (86.7%) achieved excellent result; 2 cases (4.4%) had good result. So the postoperative effective rate was 91.1% (41/45). During 12-36 month follow-up, the outcomes were excellent in 42 cases (93.3%) and good in 2 cases (4.4%), and the effective rate reached to 97.8% (44/45). No recurrence was noted. The postoperative complications were found in 2 patients (4.4%). One patient (2.2%) showed delayed facial palsy on the tenth day but was fully recovered 1 month later. Intracranial infection was noticed in 1 patient (2.2%) and was cured by using intravenous antibiotics for 2 weeks. There was no hearing impairment, hoarseness, or other complications.

CONCLUSIONS

Fully endoscopic MVD is both safe and effective in the treatment of HFS. Electrophysiological monitoring is helpful to gain a good result and reduce hearing impairment.