Role of arterioles in management of microvascular decompression in patients with hemifacial spasm

Hemifacial Spasm: Comparison of Results between Patients Older and Younger than 70 Years Operated on with Microvascular Decompression

OBJECTIVE

 The aim of the present study was to evaluate the efficacy and safety of microvascular decompression (MVD) for primary hemifacial spasm (HFS) in patients aged ≥70 years and to compare the outcome with a control cohort of younger patients(<70 years).

METHODS

 In this retrospective study, subjects were divided into two groups: an elderly group (patients who were ≥70 years) and a younger group. We compared demographic and clinical data, surgical outcome, MVD-related complications, and duration of operation and hospitalization after MVD between the two groups.

RESULTS

 At a mean follow-up of 32 ± 4.2 months, 188 elderly patients (90.4%) reported an effective outcome without need for any medication versus 379 (91.1%) of the younger cohort. There was no mortality in both cohorts. The prevalence of delayed facial palsy was 4.8% in the elderly group and 4.1% in the younger group. One (0.5%) patient in the elderly group and 3 (0.7%) patients in the younger group suffered cerebrospinal fluid (CSF) leakage. There was no significant difference between the two groups in terms of MVD-related complications, such as delayed facial palsy, hearing impairment, CSF leakage, and hematoma.

CONCLUSIONS

 MVD is an effective treatment option in elderly patients with HFS as well as in younger patients. Age itself seems to be no relevant contraindication or, alternatively, risk factor regarding MVD.

Predicting outcome of hemifacial spasm after microvascular decompression with intraoperative monitoring: A systematic review

BACKGROUND

Microvascular decompression has been established as a primary treatment for hemifacial spasm. Intraoperative monitoring is used during the surgery to guide neurosurgeons to determine whether the decompression of facial nerve from the vessel is sufficient. We performed a systematic review to assess the role of lateral spread response (LSR) monitoring in predicting hemifacial spasm outcomes after microvascular decompression.

METHOD

A systematic search of PubMed, ScienceDirect, Cochrane, and Google Scholar was conducted. We included studies that performed microvascular decompression surgery with intraoperative monitoring analyzing the correlation between lateral spread response and spasm relief. A critical appraisal was conducted for selected studies.

RESULT

Twenty-two studies comprising 6404 cases of hemifacial spasm, which underwent microvascular decompression surgery with intraoperative monitoring, were included. Of 15 articles that assessed symptoms shortly after surgery, 12 studies showed a significant correlation between lateral spread response resolution and disappearance of spasm. Four of six studies that evaluated the outcome at 3-month follow-up showed significant relationship between LSR and outcome, so did five of six articles that assessed spasm relief at 6-month follow-up. As much as 62.5% of studies (10 of 16) showed the result at long-term follow-up (≥1-year) was not significant.

CONCLUSION

Intraoperative monitoring during microvascular decompression surgery can be a useful tool to predict hemifacial spasm resolution. Though long-term outcomes of patients with LSR relief and persistence are similar, resolution of symptoms shortly after surgery will provide comfort to patients thereby improving their quality of life.

Treatment of Trigeminal Neuralgia with "Microvascular Decompression Plus" Technique

Objective  Although microvascular decompression (MVD) has been widely accepted as an effective treatment of trigeminal neuralgia (TN), some patients have not been cured. To improve the postoperative outcome, the surgical procedure should be further refined. Design  This is a retrospective study. Setting  Present study conducted at a cranial nerve disorder center. Participants  Clinical data were collected from patients with TN who had undergone surgery in our center, including 685 who had undergone traditional MVD and 576 who had undergone the "MVD plus" procedure, in which any vessel attached to the trigeminal nerve was freed away ("nerve-combing"), which was followed by intraoperative neurolysis. Main Outcome Measures  Postoperative outcomes and complications in the two groups were compared. Results  Among patients who underwent traditional MVD, the rates of immediate relief and 1-year relief were 89.9 and 86.9%, respectively; among patients who underwent MVD plus group, these rates were 95.1 and 94.6%, respectively ( p  = 0.05). Patients who underwent MVD plus initially exhibited a higher rate of facial numbness ( p  < 0.05), but this finding decreased over time and reached the same level as that in the traditional MVD group within 3 months ( p  > 0.05). Conclusion  Sufficient MVD with nerve-combing for the treatment of TN may produce a high rate of cure with less recurrence.

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.

A Rare Potential Compression Can Be Avoided by Lateral Spread Response Recordings During Microvascular Decompression for Hemifacial Spasm

The authors report a 34-year-old female with hemifacial spasm who was identified as a candidate for microvascular decompression. Lateral spread response (LSR) was not recorded at first because of anatomical shift of neurovascular relationship after drainage of cerebrospinal fluid, but they reappeared only after a piece of shredded gelatin sponge was placed near the posteroinferior cerebellar artery to expand surgical field. As the authors removed the gelatin sponge, the LSRs disappeared instantly. Subsequently, the authors put some soft shredded Teflon between the offending vessel and brainstem. Since then the authors did not find LSRs anymore. Clinical follow-up had been carried out with a questionnaire from 1 week to 3 months postoperatively, and the patient was cured with no complications. This report presented that the gelatin sponge placed in an inappropriate position resulting in compression potentially leading to the opposite effect of treatment. Such kind of excessive operation could be avoided by electrophysiological monitoring.

A multivariate analysis for delayed healing of facial muscle spasm after microvascular decompression

Objectives:

To analyze the related factors for delayed healing of facial muscle spasm after microvascular decompression.

Methods:

After microvascular decompression, 116 of 425 patients with delayed healing were followed up, and their clinical data were analyzed.

Results:

The incidence rate of postoperative delayed healing was 27.3%, which was not correlated with gender, age or intraoperative vascular compression. However, it was correlated with disease course, severity of preoperative symptoms, arteriosclerosis and abnormal facial muscle response. The duration of delayed healing was positively correlated with preoperative disease course.

Conclusions:

Delayed healing is a common phenomenon after microvascular decompression for facial muscle spasm, with an elusive reason. Therefore, the treatment outcomes should be evaluated after one year of follow-up.

Hemimasticatory Spasm with a Single Venous Compression Treated with Microvascular Decompression of the Trigeminal Motor Rootlet

BACKGROUND

Hemimasticatory spasm is a very rare disorder of the trigeminal motor rootlet that is characterized by a paroxysmal involuntary contraction of the jaw-closing muscles. The mechanisms for hemimasticatory spasm remain unclear, and an efficient treatment strategy still needs to be developed.

CASE DESCRIPTION

We report a case of a successful treatment of hemimasticatory spasm with single venous compression via microvascular decompression of the trigeminal motor rootlet.

CONCLUSIONS

Our report shows that a single venous compression may be also responsible for idiopathic hemimasticatory spasm which can be cured by microvascular decompression. This is the first report on hemimasticatory compressed by a single vein in the world.

An optimized abnormal muscle response recording method for intraoperative monitoring of hemifacial spasm and its long-term prognostic value

BACKGROUND

Intraoperative electrophysiological monitoring is used to determine whether decompression is sufficient during microvascular decompression (MVD) for hemifacial spasm (HFS). However, the real offending vessel is sometimes neglected by the neurosurgeons. Here, we reported our experience in using optimized abnormal muscle response (AMR) monitoring and continuous intraoperative monitoring for MVD.

METHODS

This study included 2161 HFS patients who underwent MVD using traditional (1023 patients) and optimized (1138 patients) methods. Modified AMR monitoring was adopted in our study, with the zygomatic branch of the facial nerve stimulated and the temporal branch, buccal branch, marginal mandibular branch and cervical branch of the facial nerve detected for AMR. These cases were analyzed retrospectively with emphasis on the postoperative outcomes and intraoperative findings. The therapeutic effect was evaluated at day 1, month 3 and year 1 after operation.

RESULTS

The relief rate at day 1, month 3 and year 1 after operation for patients who employed optimized AMR recording method was 95.1%, 97.4% and 99.3%, comparing with 92.2%, 95.0% and 97.8% in traditional method. There was significant difference in achieved immediate remission and recovery rate during 12-month follow-up between the two groups (P < 0.05). The modified intraoperative monitoring showed the sensitivity of AMR disappearance to judge the relief at day 1, month 3 and year 1 after HFS operation was 95.7%, 96.3% and 97.3%, respectively; the specificity was 44.6%, 43.3% and 50.0%, respectively; the accuracy was 93.1%, 94.9% and 97.4%, respectively.

CONCLUSIONS

Our findings demonstrated that the optimized method could improve the positive detection rate of AMR and accuracy of decompression effect prediction. The evaluation for the decompression effect by optimized intraoperative monitoring can increase the immediate remission rate and reduce the delayed recovery rate.

Management of symptomatic hemifacial spasm or trigeminal neuralgia

Hemifacial spasm (HFS) or trigeminal neuralgia (TN) is a kind of hyperactivity disorder of cranial nerves caused by vascular compression. However, sometimes, the disease may arise from nerve damage produced by tumors, which was called as symptomatic HFS/TN. Until now, little is known about the exact mechanism and the necessity of microvascular decompression (MVD) regarding the tumor-induced HFS/TN, which is necessary to be retrospectively analyzed in a considerable sample. Among the 4021 patients who underwent MVD in our department between 2006 and 2014, 44 were finally diagnosed as symptomatic HFS or TN. These patients were focused in this study and their clinical features as well as intraoperative findings and postoperative outcomes were retrospectively investigated. Data analysis exhibited the symptomatic HFS/TN cases accounted for 1.1 % in the study, which were caused by epidermoid in 18 (40.9 %) and meningioma in 15 (34.1 %) followed by neuroma in 7 (15.9 %) as well as aneurysm in 2 (4.5 %) and arteriovenous malformation in 2 (4.5 %). Compared to those with idiopathic HFS/TN, younger females were more susceptible (p < 0.05). After resection of the neoplasm, the offending vessel was identified in 26 (59.1 %), which were followed by MVD process. Postoperatively, the symptoms relief rate was 88.6 %. Our study showed that surgical management of patients with symptomatic HFS/TN may lead to a satisfactory result, yet those primary lesions should be removed firstly. In some cases, a microvascular decompression process might be unnecessary afterward, but the entire nerve root should be checked to exclude any vessel in contact with.

Upregulation of Nav1.8 in demyelinated facial nerves might be relevant to the generation of hemifacial spasm

Our previous studies demonstrated that the abnormal muscle response could vanish when the ipsilateral superior cervical ganglion was removed and reappear when norepinephrine was dripped at the neurovascular conflict site. Evidentially, we believed that the mechanism of hemifacial spasm should involve emersion of ectopical action potential in the compressed facial nerve fibers. As the action potential is ignited by ion channel opening, we focused on Nav1.8 that has been found overexpressed in peripheral nerve while damaged. In this study, Moller model was adopted, 20 Sprague-Dawley rats underwent drip of norepinephrine, and the abnormal muscle response wave was monitored in 14 rats. Antibodies against unique epitopes of the α subunit of sodium channel isoforms were used to detect the Nav1.8 neuronal isoforms, and the immunohistochemistry showed strong staining in 13 rats, which were all in the abnormal muscle response positive group (P < 0.05). Accordingly, we concluded that the substance of hemifacial spasm is an ectopic action potential that emerged on the damaged facial nerve, which might be coupled by Nav1.8.

Advances in microvascular decompression for hemifacial spasm

Primary hemifacial spasm (HFS) is a disorder that causes frequent involuntary contractions in the muscles on one side of the face, due to a blood vessel compressing the nerve at its root exit zone (REZ) from the brainstem. Numerous prospective and retrospective case series have confirmed the efficacy of microvascular decompression (MVD) of the facial nerve in patients with HFS. However, while MVD is effective, there are still significant postoperative complications. In this paper, recent technological advances related to MVD (such as lateral spread response, brainstem auditory evokes potential, three dimensional time of flight magnetic resonance angiography, intraoperative neuroendoscopy) are reviewed for the purposes of improving MVD treatment efficacy and reducing postoperative complications.

Delayed relief of hemifacial spasm after microvascular decompression: can it be avoided?

BACKGROUND

Although microvascular decompression (MVD) surgery has been widely accepted as an effective treatment for hemifacial spasm (HFS), delayed relief cases have been frequently reported. Therefore, the value of an immediate redo MVD should be discussed.

METHODS

This study included 1,435 HFS patients who underwent MVD with intraoperative abnormal muscle response (AMR) monitoring from 2011 through 2013 at XinHua Hospital. These cases were analyzed retrospectively with emphasis on the postoperative outcomes and introaperative findings.

RESULTS

After MVD, 1,384 HFS patients obtained relief immediately. The 51 unrelieved patients underwent AMR monitoring again the next day; this was positive in 48 and negative in 3 patients. These three patients with negative AMR obtained relief spontaneously within a week. Among the 48 positive patients, 31 and 11 were underwent redo MVD within a week and 5-22 months, respectively, and all achieved relief after the second operation. Of the six remainig patients, two obtained relief within 2 months and 4 remained unchanged in the up-to-3-year's follow-up period. In redo MVDs, insufficient decompression of the facial nerve accounted for the failure. Finally, in this database, the immediate postoperative cure rate was 96.4 %; with earlier redo MVD, the final cure rate could be increased to 99.9 %.

CONCLUSIONS

Despite being a reasonable remedy for HFS in the hands of an experienced neurosurgeon, sometimes small vessels can be missed while managing the main offending arteries during MVDs, which might account for the delayed relief. Therefore, reexamination of the AMR is necessary for unimproved patients; if a positive result is recorded, an immediate redo MVD is suggested.

Hemifacial spasm and neurovascular compression

Hemifacial spasm (HFS) is characterized by involuntary unilateral contractions of the muscles innervated by the ipsilateral facial nerve, usually starting around the eyes before progressing inferiorly to the cheek, mouth, and neck. Its prevalence is 9.8 per 100,000 persons with an average age of onset of 44 years. The accepted pathophysiology of HFS suggests that it is a disease process of the nerve root entry zone of the facial nerve. HFS can be divided into two types: primary and secondary. Primary HFS is triggered by vascular compression whereas secondary HFS comprises all other causes of facial nerve damage. Clinical examination and imaging modalities such as electromyography (EMG) and magnetic resonance imaging (MRI) are useful to differentiate HFS from other facial movement disorders and for intraoperative planning. The standard medical management for HFS is botulinum neurotoxin (BoNT) injections, which provides low-risk but limited symptomatic relief. The only curative treatment for HFS is microvascular decompression (MVD), a surgical intervention that provides lasting symptomatic relief by reducing compression of the facial nerve root. With a low rate of complications such as hearing loss, MVD remains the treatment of choice for HFS patients as intraoperative technique and monitoring continue to improve.

Microvascular decompression surgery: surgical principles and technical nuances based on 4000 cases

BACKGROUND

As an etiological treatment of trigeminal neuralgia (TN) and hemifacial spasm (HFS), microvascular decompression (MVD) has been popularized around the world. However, as a functional operation in the cerebellopontine angle (CPA), this process can be risky and the postoperative outcomes might not be good enough sometimes.

OBJECTIVE

In order to obtain a better result with less complication, this surgery should be further addressed.

METHODS

With experience of more than 4000 MVDs, we have gained knowledge about the operative technique. Through abundant intraoperative photos, each step of the procedure was demonstrated in detail and the surgical strategy was focused.

RESULTS

The principle of MVD is to separate the nerve-vessel confliction rather than isolate it with prostheses. A prompt identification of the conflict site is important, which hinges on a good exposure. A satisfactory working space can be established by an appropriate positioning of the patient's head and a proper craniectomy as well as a rational approach. A sharp dissection of arachnoids leads to a maximal visualization of the entire intracranial course of the nerve root. All the vessels contacting the trigeminal or facial nerve should be treated. Intraoperative electrophysiological mentoring is helpful to distinguish the offending artery for hemifacial cases.

CONCLUSION

MVD is an effective treatment for the patient with TN or HFS. Immediate relief can be achieved by an experienced neurosurgeon with good knowledge of regional anatomy. A safe surgery is the tenet of MVD, and accordingly, no single step of the procedure should be ignored.