Microvascular decompression for hemifacial spasm associated with the vertebral artery

Dynamic changes of abnormal muscle response during decompression procedures in double compression-type hemifacial spasm

Background

Hemifacial spasm (HFS) is a neurovascular movement caused by vascular compression of the facial nerve in its root exit zone (REZ). Cases of HFS caused by double compression (DC) in both REZ and the cisternal portion (CP) have been sporadically reported. The nature of DC-type HFS is still not fully understood. Compression in CP is often overlooked, resulting in reoperation in DC-type HFS cases.

Case Description

A 48-year-old man with a 3-year history of left HFS was admitted to our department. Magnetic resonance imaging revealed that the vertebral artery (VA) passed around REZ of the facial nerve, and the anterior inferior cerebellar artery (AICA) was in contact with the facial nerve in CP. Microvascular decompression was performed while monitoring any abnormal muscle response (AMR). Although VA was dissected and detached from REZ, AMR showed only a transient decrease and the amplitude of the AMR wave soon recovered and subsequently increased. No other vessels compressing REZ beneath VA were found. AICA attached to the facial nerve in CP and was compressed upward by VA. When AICA was moved from the facial nerve in CP after the transposition of VA, AMR was immediately resolved. After surgery, the patient was completely free from HFS.

Conclusion

In DC-type HFS, precise preoperative diagnosis and intraoperative identification of the culprit vessel are difficult. In DC-type HFS, decompression of one side of a vessel may exacerbate the compression of the other side. In such a case, AMR helps us become aware of compressions in CP that we may preoperatively overlook. AMR is useful for identifying the exact culprit vessels and recognizing any compression changes caused by intraoperative manipulations.

Bridge-layered decompression technique for vertebral artery-involved hemifacial spasm: technical note

BACKGROUND

Hemifacial spasm (HFS) is most effectively treated with microvascular decompression (MVD). However, there are certain challenges in performing MVD for HFS when the vertebral artery (VA) is involved in compressing the facial nerve (VA-involved). This study aimed to introduce a "bridge-layered" decompression technique for treating patients with VA-involved HFS and to evaluate its efficacy and safety to treat patients with HFS.

METHODS

A single-center retrospective analysis was conducted on the clinical data of 62 patients with VA-involved HFS. The tortuous trunk of VA was lifted by a multi-point "bridge" decompression technique to avoid excessive traction of the cerebellum and reduce the risk of damage to the facial-acoustic nerve complex. To fully decompress all the responsible vessels, the branch vessels of VA were then isolated using the "layered" decompression technique.

RESULTS

Among the 62 patients, 59 patients were cured immediately after the surgery, two patients were delayed cured after two months, and one had occasional facial muscle twitching after the surgery. Patients were followed up for an average of 19.5 months. The long-term follow-up results showed that all patients had no recurrence of HFS during the follow-up period, and no patients developed hearing loss, facial paralysis, or other permanent neurological damage complications. Only two patients developed tinnitus after the surgery.

CONCLUSION

The "bridge-layered" decompression technique could effectively treat VA-involved HFS with satisfactory safety and a low risk of hearing loss. The technique could be used as a reference for decompression surgery for VA-involved HFS.

The outcome of microvascular decompression for hemifacial spasm: a systematic review and meta-analysis

Microvascular decompression (MVD) is the first choice of surgery for hemifacial spasm (HFS). MVD surgery for vertebral artery (VA)-associated HFS is more difficult than for non-VA-associated HFS. There is controversy about the cure rate and complication of MVD for HFS in previous studies. We searched PubMed, Web of Science, and Embase for relevant publications. Based on the search results, we compared the outcomes of MVD for VA-associated HFS and non-VA-associated HFS. At the same time, we analyzed spasm-free rates and the complications and assessed the relationship between VA-associated HFS and gender, left side, and age. For analysis, six studies that included 2952 patients in the VA-associated group and 604 in the non-VA-associated group were selected. The effective rate of MVD was not significantly different between both groups (OR = 1.16, 95% CI 0.81-1.67, P = 0.42). Compared to non-VA-associated group, the transient complications (OR = 0.64, 95% CI 0.46-0.89, P = 0.008) and permanent complications (OR = 0.28, 95% CI 0.15-0.54, P = 0.0001) occurred more frequently in VA-associated group. The rate of hearing loss was significantly higher in VA-associated HFS than non-VA-associated HFS (OR = 0.35, 95% CI 0.19-0.64, P = 0.0007); the facial paralysis after operation was not significantly different between both groups (OR = 1.25, 95% CI 0.91-1.72, P = 0.17). There were older patients (WMD = 3.67, 95% CI 3.29-4.05, P < 0.00001) and more left-sided HFS (OR = 0.23, 95% CI 0.19 - 0.29, P < 0.0002) in the VA-associated HFS group than non-VA-associated HFS group, while the non-VA-associated HFS group was female-dominated (OR = 1.58, 95% CI 1.32 - 1.89, P < 0.00001). Both groups achieved good results in MVD cure rates. In VA-associated HFS, the complication rate of decompression and the rate of hearing loss after operation were higher than in non-VA-associated HFS, but the facial paralysis after operation was similar in both groups, and most complications were transient and disappeared during follow-up. VA-associated HFS is more prevalent in older adults, less prevalent in women, and more predominantly left-sided. More clinical studies are needed to better compare the efficacy and complication of MVD between both groups.

Bridge technique for hemifacial spasm with vertebral artery involvement

BACKGROUND

To assess efficacy and safety of a newly developed decompression technique in microvascular decompression for hemifacial spasm (HFS) with vertebral artery (VA) involvement.

METHODS

A rigid Teflon (Bard^® PTFE Felt Pledget, USA) with the ends placed between the lower pons and the flocculus creates a free space over the root exit zone (REZ) of the facial nerve (bridge technique). The bridge technique and the conventional sling technique for VA-related neurovascular compression were compared retrospectively in 60 patients. Elapsed time for decompression, number of Teflon pieces used during the procedure, and incidences of intraoperative manipulation to the lower cranial nerves were investigated. Postoperative outcomes and complications were retrospectively compared in both techniques.

RESULTS

The time from recognition of the REZ to completion of the decompression maneuvers was significantly shorter, and fewer Teflon pieces were required in the bridge technique than in the sling technique. Lower cranial nerve manipulations were performed less in the bridge technique. Although statistical analyses revealed no significant differences in surgical outcomes except spasm-free at postoperative 1 month, the bridge technique is confirmed to provide spasm-free outcomes in the long-term without notable complications.

CONCLUSIONS

The bridge technique is a safe and effective decompression method for VA-involved HFS.

Involvement of the vertebral artery in hemifacial spasm: clinical features and surgical strategy

The vertebral artery (VA)-involved hemifacial spasm (HFS) has distinctive clinical features and performing microvascular decompression (MVD) is challenging. We described the clinical presentations of VA-involved HFS and the outcomes of MVD using the interposition method. Between January 2008 and March 2015, MVD was performed in 271 patients with VA-involved HFS. Demographic characteristics, preoperative severity, intraoperative findings, spasm-free outcome, and complications were retrospectively evaluated. A control group of 1500 consecutive patients with non-VA-involved HFS was enrolled. VA-involved HFS was associated with older age (p < 0.001), less female predominance (p < 0.001), more left-sided predominance (p < 0.001), and rapid symptom progression before MVD (p < 0.001). The Teflon Fulcrum method allowed intraoperative identification of the neurovascular compression site in 92.6% of the cases, and showed more severe indentation on the facial nerve (p < 0.001). Changes in the brainstem auditory evoked potentials during MVD (p < 0.001) and postoperative non-serviceable hearing loss (p < 0.001) were more frequent in patients with VA-involved than in non-VA-involved HFS. The spasm-free outcome and overall complication rates after MVD were not significantly different between the groups. VA-involved HFS has distinctive clinical features and poses a major surgical challenge for MVD success. The interposition method is a feasible surgical strategy in VA-involved HFS.

Spasm Freedom Following Microvascular Decompression for Hemifacial Spasm: Systematic Review and Meta-Analysis

BACKGROUND

Hemifacial spasm (HFS) is a debilitating disorder characterized by intermittent involuntary movement of muscles innervated by the facial nerve. HFS is caused by neurovascular compression along the facial nerve root exit zone and can be treated by microvascular decompression (MVD). The goal was to determine rates and predictors of spasm freedom after MVD for HFS.

METHODS

A literature search using the key terms "microvascular decompression" and "hemifacial spasm" was performed. The primary outcome variable was spasm freedom at last follow-up. Analysis was completed to evaluate for variables associated with spasm-free outcome.

RESULTS

A total of 39 studies including 6249 patients were analyzed. Overall spasm freedom rate was 90.5% (5652/6249) at a follow-up of 1.25 ± 0.04 years. There was no significant relationship between spasm freedom versus persistent spasm and age at surgery, timing of follow-up, gender, disease duration, side of disease, or vessel type. Spasm freedom was more likely after an initial surgery versus a redo MVD (odds ratio 4.16, 95% confidence interval 1.99-8.68; P < 0.01).

CONCLUSIONS

MVD works well for HFS with cure rates >90% at 1-year follow-up in 6249 patients from 39 studies. A significant predictor of long-term spasm freedom at 1 year was an initial MVD as compared to repeat MVD. The majority of published manuscripts on MVD for HFS are heterogeneous single-institutional retrospective studies. As such, a large-scale meta-analysis reporting outcome rates and evaluating significant predictors of spasm freedom provides utility in the absence of randomized controlled studies.

The efficacy of temporary clamping of V3 with a suboccipital far-lateral approach in microvascular decompression for Hemifacial spasm associated with the vertebral artery

Hemifacial spasm (HFS) is often caused by compression of the vertebral artery (VA) directly or indirectly as a result of other intervening vessels, so VA-associated HFS is difficult to treat. Recently, we have achieved good surgical outcomes using a far lateral approach and temporary clamping of V3 for VA-associated HFS. Herein, we present our method with an accompanying surgical video. From April 2018 to March 2019, 5 patients with VA-associated HFS underwent surgery, and pre-and postoperative symptoms and postoperative complications were evaluated. In the procedure, the suboccipital muscles were dissected and reflected layer by layer, and the extracranial VA (V3) was secured within the suboccipital triangle. A lateral suboccipital craniotomy followed by far lateral drilling was made to widen the surgical field from the caudolateral side. After reducing the VA flow pressure by temporary clamping of V3, the VA was transposed using a Teflon sling via two triangular space above and below the lower cranial nerves (LCNs). Causative vessels included direct VA compression in two cases and intervening vessels in three cases. The symptoms disappeared in four cases and improved satisfactorily in one case. One patient had mild hearing loss (approximately 10 dB) and hoarseness, but both improved 9 months after surgery. There was no postoperative cerebrospinal fluid leakage in any cases. A wide surgical field via the far lateral approach and the temporary clamping of V3 contributed to thorough observation of the REZ and safe and complete VA transposition.

Clinical analysis of repeat microvascular decompression for recurrent hemifacial spasm

The aim of this study was to investigate the effects of repeat microvascular decompression (MVD) for recurrent hemifacial spasm (HFS). The clinical features, surgical findings, outcomes, and complications of 13 patients who underwent MVD with a history of prior MVD in Xuanwu Hospital between January 2010 and May 2017 were analysed retrospectively. All patients were successfully treated for their HFS but experienced recurrent symptoms and received repeat MVD. Teflon felt factors (9/13, 69.2%) and vascular changes (4/13, 30.8%) were the main reasons for recurrent HFS. With a mean follow-up of 34.6 months after surgery (ranging from 12 to 92 months), 11 (84.6%) patients achieved complete or major spasm alleviation and two patients (15.4%) achieved fair outcomes. Surgical complications included transited mild to moderate facial weakness in two patients (15.4%). None of the patients had serious surgical morbidities. Repeat MVD is an effective and safe treatment for recurrent HFS.