Reoperation for Persistent or Recurrent Hemifacial Spasm after Microvascular Decompression

Efficacy and safety of reoperation for residual or recurrent hemifacial spasm after microvascular decompression: a systematic review and meta-analysis

The efficacy and safety of revision microscopic microvascular decompression (microscopic MVD) for treating residual or recurrent hemifacial spasm (HFS) remain uncertain. We conducted a systematic review and meta-analysis to evaluate the benefits and risks associated with this reoperation, focusing primarily on spasm relief, facial palsy, and hearing impairment. This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. We performed a comprehensive search of PubMed, Embase, Web of Science, and the Cochrane Library for eligible articles from their inception through June 2024. A total of 17 studies involving 719 patients were included in this meta-analysis. Among these patients, 668 experienced overall symptom relief following reoperation, resulting in a relief rate of 94% (95% CI: 92-96%). Complete relief was achieved in 603 patients, corresponding to a rate of 87% (95% CI: 80-93%). Transient facial palsy developed in 4% (95% CI: 1-8%) of patients, while persistent facial palsy was observed in 5% (95% CI: 2-8%) of patients following reoperation. Transient hearing impairment occurred in 1% (95% CI: 0-3%) of patients, while persistent hearing impairment was reported in 4% (95% CI: 1-7%) of patients. Patients with recurrent HFS have significantly lower overall and complete relief rates after reoperation compared to those with residual HFS and are at higher risk of long-term hearing loss. Our study suggests that reoperation for residual or recurrent HFS after microscopic MVD could be considered a safe and effective treatment option. Early reoperation may be indicated in specific cases, and the timing should be tailored to each patient's specific circumstances to optimize outcomes.

Optimized microvascular decompression surgery for improving the results of hemifacial spasm: an analysis of reoperations

Microvascular decompression (MVD) surgery is an effective curative treatment for hemifacial spasm (HFS). This study aims to establish techniques that may lead to favorable outcomes by analyzing reoperations in patients with persistent or recurrent HFS.Patients who exhibited persistent or recurrent HFS symptoms after prior MVD surgery were identified as candidates for reoperation. Information regarding the reoperations was collected by tracing the entire surgical procedures and peri-operative management. Clinical manifestations and follow-up data were obtained from the hospital records and subsequent visits.Twenty-six patients underwent repeat MVD surgery. Among them, multi-culprit neurovascular compression (NVC) was identified as the primary cause of failure to response to the previous operation in 73.08% of cases. Pure tissue adhesion accounted for 38.46% of cases, while shredded Teflon pledget (STP) shifting was observed in 7.69% of cases. Postoperative outcomes were assessed through revisits and categorized into four groups: excellent (76.92%), good (15.38%), fair (7.69%), and poor (0%). The longest follow-up period exceeded 65 moths.The trans-lateral suboccipital infra-floccular approach provides a better visual field. Examination of entire length of the facial nerve is essential. STP with gelatin sponge implantation is a suitable material for facilitating nerve and vascular positioning and reducing adhesion.

Safety and efficacy of endoscope-assisted versus microscopic microvascular decompression surgery for hemifacial spasm: a prospective cohort study

Microscopic microvascular decompression (M-MVD) is a classical treatment for relieving long-term hemifacial spasms (HFS). An endoscopy technique has recently been introduced to improve M-MVD; however, this application remains debatable. This study compared the safety and effectiveness of endoscope-assisted microvascular decompression (EA-MVD) and M-MVD for HFS. From February 2021 to September 2022, we enrolled 49 patients with HFS assigned to the EA-MVD (n = 26) and M-MVD (n = 23) groups. The patients were assessed with Park YS grades, operative time, hospital days, and complications. Evaluations were performed in the early postoperative period, at one month, 3 months, 6 months, and at least 12 months. Twenty-three (23/26, 88.5%) patients in the EA-MVD group and 20 (20/23, 87.0%) patients in the M-MVD group achieved spasm-free relief, ranging over "excellent" and "good" Park YS grades. The operative time in the EA-MVD and M-MVD groups were 143 ± 28 min and 145 ± 22 min (p = 0.002). The duration of hospital stay was 6.8 ± 0.8 days and 7.2 ± 1.3 days in the EA-MVD and M-MVD groups (p = 0.002), respectively. All surgeries for HFS were successful, with no death, stroke, hearing loss, facial numbness, or other extreme complications. In conclusion, EA-MVD, compared with M-MVD, demonstrated equally effective outcomes with decreased operative time and hospital stays, providing bright intraoperative illumination and flexible surgical vision.

Surgical treatment of hemifacial spasms: how to predict failure and complications through a series of 200 patients

Primary hemifacial spasm (pHFS) is a benign but disabling movement disorder caused by a neurovascular conflict involving the facial nerve. Surgical treatment by microvascular decompression (MVD) is the most effective therapeutic. Predictors of surgical failure and surgical complications are still lacking. The aim of this study is to identify such predictors through the retrospective analysis of a series of 200 consecutive patients. All patients who underwent MVD for pHFS from January 1991 to December 2017 were included. All patients had at least two years follow-up. In addition to the demographic data, the outcome and the complications were collected. The primary outcome analysis showed that 7.5% of patients had a recurrence. Multiple and AICA related neurovascular conflicts were statistically associated to a higher recurrence rate after MVD (respectively p < 0.001 and p = 0.02). Permanent facial palsy occurred in 2.5% of patients, hearing loss in 9.0% (2.0% of complete unilateral impairment) and dizziness in 2.5%. The risk of each of these peripheral neurological impairments was statistically increased by a long duration between the first pHFS symptom and the MVD (p < 0.001). In case of recurrence, a second MDV was offered. Long term follow-up showed that all patients had a complete resolution of the HFS. Post-operative complication rate was not significantly increased after a second MVD. Multiple and AICA related neurovascular conflicts are associated to a higher risk of surgical failure. When a pHFS recurrence occurs, a second surgical procedure is associated with excellent outcome without significant increase of post-operative complications and should therefore be recommended.

Hemifacial Spasm Caused by Vascular Compression of the Anterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Common Trunk Anomaly at the Cisternal Portion of the Facial Nerve: A Case Report

W report the first case of hemifacial spasm (HFS) caused by vascular compression of the anterior inferior cerebellar artery (AICA)-posterior inferior cerebellar artery (PICA) common trunk anomaly at the cisternal portion of cranial nerve VII (CN VII). A 71-year-old female with a typical right HFS was admitted to our hospital. As per her magnetic resonance (MR) imaging results, no offending arteries were noted around the CN VII root exit zone (REZ). Computed tomography angiography revealed an AICA-PICA common trunk anomaly with a dominant PICA, with the rostral branch of the AICA-PICA common trunk anomaly compressing the CN VII at the cisternal portion. The patient underwent microvascular decompression (MVD), and the HFS disappeared after surgery. The amplitude of the abnormal muscle responses (AMR) disappeared immediately after complete transposition of the offending artery. However, the patient experienced mild transient facial palsy 3 days after MVD which was eventually resolved with the administration of vitamin B12. No HFS recurrence was observed during the 1-year follow-up period. The AICA-PICA common trunk anomaly has been found to cause HFS as it compressed the CN VII at the cisternal portion, and not at the REZ. AMR monitoring might be helpful for cases where the unusual vessel particularly compresses the CN VII.

Microvascular decompression for pediatric onset trigeminal neuralgia: patterns and variation

OBJECTIVES

Pediatric trigeminal neuralgia has been rarely reported in the literature, which were only 28 cases. Although microvascular decompression (MVD) has been widely accepted as effective therapy for trigeminal neuralgia, the etiology and surgical treatment of pediatric ones are seldom addressed. We report our experience with MVD for pediatric trigeminal neuralgia patients with emphasis on the vascular conflict patterns and surgical skills.

METHODS

This retrospective report included 11 pediatric TN patients, who underwent MVD and were followed for 3-86 months. The data were retrospectively analyzed with emphasis on the clinical features.

RESULTS

This series included 4 boys and 7 girls with average age of 13 ± 3.4 years old, their onset age were from 7 to 18 years old. The singular vein and combined artery/vein conflictions account for 7/11. 9 (81.8%) patients achieved immediate excellent outcomes. One recurrence was observed after 5 months and refused the second surgery.

CONCLUSIONS

The etiology of pediatric onset trigeminal neuralgia is still vascular conflict, whose patterns are different from adults, of which combined artery/vein and singular venous compression patterns have a much more higher proportion. Because of the smaller operative space and fragile-thin venous wall with adhesion to other structures, it is much more difficult to decompress the trigeminal nerve among pediatric patients. Sufficient arachnoid release, full exploration, and decompression along the trigeminal nerve were necessary, which will increase the excellent rate among pediatric patients.

Facial root entry/exit zone contact in microvascular decompression for hemifacial spasm: a historical control study

Background

Microvascular decompression (MVD) surgery is recognized as an effective treatment for hemifacial spasm (HFS). In MVD surgery, biocompatible materials are usually implanted in situ at the neurovascular conflict site in contact with the offending vessel and the facial root entry/exit zone (REZ). Another procedure of implanting the materials between the responsible vessel and the supraolivary fossa without REZ contact has also been applied. However, it is unclear whether there are any differences between these 2 procedures (REZ-contact procedure vs. REZ-non-contact procedure). Therefore, the aim of the present study was to investigate the effect of the placement of implants (contacting or not contacting the facial REZ) on surgical operations and outcomes

Methods

A historical control study was performed. Clinical data of HFS patients who underwent MVD between December 2016 and November 2018 were reviewed and categorized into 1 group with the REZ-contact procedure or another group with the REZ-non-contact procedure according to the decompression strategy they received. Clinical demographics, postoperative outcomes, and complications were collected and compared between the two groups.

Results

Not all patients are suitable for REZ-non-contact decompression. A total of 205 patients were enrolled: 112 in the REZ-contact group and 93 in the REZ-non-contact group. In the early postoperative period, the complete cure rate in the REZ-non-contact group was significantly higher than that in the REZ-contact group. The reappearance and partial relief rates in the REZ-contact group were significantly higher than those in the REZ-non-contact group. The incidence of short-term neurological complications, especially hearing loss and transient facial palsy, was lower in the REZ-non-contact group (P=0.043). But for long-term follow-up of >1 year, there was no significant difference between the two groups in either curative effects or neurological complications. The operating time for REZ-non-contact decompression was relatively longer than for REZ-contact decompression (P=0.000). An unexpected subdural hemorrhage occurred in the REZ-non-contact group.

Conclusions

REZ-non-contact decompression procedure showed superiority only in short-term postoperative outcomes. Given its limitations and potential risks, the REZ-non-contact procedure can be used as an alternative individualized strategy in MVD, and there is no need to pursue REZ-non-contact during the decompression.

Wide distribution of central myelin segment along the facial nerve might explain hemifacial spasm with distal nerve compression

INTRODUCTION

Many researchers have assumed that neurovascular compression of the facial nerve at the site covered by central myelin sheath causes hemifacial spasm. However, some cases do not correspond to this hypothesis. The aim of this study was to clarify the myelin histology in the facial nerve.

MATERIALS AND METHODS

Histological analyses were conducted on 134 facial nerves from 67 cadavers. Three dimensions were measured in these sections: the length from the upper border of the medullopontine sulcus to the boundary between the central and peripheral myelin sheath along the anterior side; the length from the detachment point of the brain stem to the boundary along the posterior side; and the length of the transitional zone (TZ), known as the Obersteiner-Redlich zone.

RESULTS

Of the 134 facial nerves, 41 were available for study. The length of the central myelin segment ranged from 4.62 to 12.6 mm (mean 8.06 mm; median 7.98 mm) along the anterior side and from 0.00 to 4.58 mm (mean 1.68 mm; median 1.42 mm) along the posterior side of the facial nerve, and the length of the TZ ranged from 0.00 to 2.76 mm (mean 1.51 mm; median 1.42 mm).

CONCLUSIONS

In this study, the length of the central myelin segment in the facial nerve was found to be longer than that previously reported.

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.

Surgical Outcomes of Revision Microvascular Decompression for Persistent or Recurrent Hemifacial Spasm After Surgery: Analysis of Radiologic and Intraoperative Findings

OBJECTIVES

Microvascular decompression (MVD) is the treatment of choice for hemifacial spasm (HFS), due to the high rate of complete resolution associated with MVD. However, some patients experience recurrent or persistent symptoms after surgery. In this study, we evaluated the causes of recurrence or failure based on our surgical experience with revision of MVD for HFS and analyzed the relationship between surgical outcomes and radiologic and intraoperative findings.

METHODS

Among more than 2500 patients who underwent MVD surgery for HFS, 23 patients received a second MVD in our hospital from January 2002 to December 2017. Three-dimensional time-of-flight magnetic resonance angiography and reconstructed imaging were used to identify the culprit vessel and its conflict on the root exit zone (REZ) of the facial nerve. We reviewed patients' medical records and operation videos to identify the missing points of first surgery.

RESULTS

In our experience with revision of MVD, 8 patients had incomplete decompression, such as single-vessel decompression of multiple offending vessels. Teflon was not detected at the REZ but was found in other locations in 12 patients. Three patients had severe adhesion with previous Teflon around the REZ. Nineteen patients had excellent surgical outcomes at immediate postoperative evaluation; 20 patients showed spasm disappearance at 1 year after surgery and 3 patients showed persistent symptoms. Neurovascular contacts around the REZ of the facial nerve were revealed on magnetic resonance imaging of incomplete decompression and Teflon malposition patient groups. There were no clear neurovascular contacts in the patients with severe Teflon adhesion.

CONCLUSIONS

The decision regarding secondary MVD for persistent or recurrent spasm is troubling. However, if neurovascular contact was observed in the MRI of the patient and there were offending vessels, the surgical outcome might be favorable.

Hemifacial Spasm Caused by Veins Confirmed by Intraoperative Monitoring of Abnormal Muscle Response

Background

Hemifacial spasm (HFS) is a benign disease caused by the hyper excitement of facial nerves owing to vessel compression. The offending vessels are usually arteries, such as anterior and posterior inferior cerebellar or vertebral arteries, but there are few reports of vein involvement cases.

Objective

The aim of this study was to investigate veins as offending vessels in patients with HFS confirmed by abnormal muscle response (AMR).

Methods

We analyzed 5 patients with HFS caused by veins among 78 patients with HFS over the past 10 years. All patients underwent microvascular decompression (MVD) with AMR monitoring, whereas 3 of them underwent a second MVD. The mean follow-up time was 97 months.

Results

Arteries were thoroughly decompressed in 3 patients with a failed first MVD surgery who received a second surgery, during which veins at the root exit point (RExP) were decompressed with the disappearance or a significant decrease in the amplitude of AMR. Two patients showed spasm resolution after the first surgery when veins were decompressed together with the disappearance of AMR. The location of veins was RExP and the cisternal portion. All patients had excellent outcomes within 3 months, and no complications were observed.

Conclusions

Veins can be offending vessels in HFS patients. AMR is useful to determine the endpoint in these cases. Once arteries are decompressed thoroughly with residual AMR, surrounding veins at unusual sites, such as the RExP or the cisternal portion, must be checked to prevent persistent HFS. Complete decompression of veins leads to a good clinical outcome.

Long-Term Outcome of Repeat Microvascular Decompression for Hemifacial Spasm

OBJECTIVE

Although repeat microvascular decompression (MVD) for hemifacial spasm (HFS) in patients with failed prior MVD is potentially curative, little is known about the long-term results of repeat MVD. We aimed to evaluate the long-term outcomes and complications after repeat MVD for HFS.

METHODS

We performed repeat MVD on 78 consecutive patients who had undergone a prior MVD >1 year previously. Follow-up data were available for 58 patients, with a median follow-up period of 8.6 years (range, 6.9-10.2 years). The patients were assessed for intraoperative findings, relief results, and complications at discharge and at follow-up, as well as the associations between the preoperative characteristics and outcomes.

RESULTS

At discharge, of 78 patients with repeat MVD, 72 (92.3%) achieved complete spasm resolution and 1 (2.6%) had significantly improved spasm resolution. Of all patients, 9% (7 of 78) presented short-term complications, including partial hearing loss, hemifacial paresis, and cerebrospinal fluid leak. At follow-up, 45 of 58 (77.6%) patients had complete relief and 10 of 58 (17.2%) had improved relief. Permanent complications occurred in 14 patients (24.1%), with partial hearing loss and mild hemifacial paresis being the most common. Despite the complications, 51 of 58 patients (91.4%) reported an excellent life quality. No significant correlation was found between preoperative characteristics, such as age, interval to prior MVD, or interval to recurrence, and outcomes including short-term or long-term relief results and complications.

CONCLUSIONS

Repeat MVD provides lasting relief for most patients with persistent or recurrent HFS, albeit with a relatively high complication rate.

Long-term surgical results in microvascular decompression for hemifacial spasm: efficacy, morbidity and quality of life

Hemifacial spasm is a condition that may severely reduce patients' quality of life. Microvascular decompression is the neurosurgical treatment of choice. The objective of this work was to describe the efficacy and morbidity of microvascular decompression for hemifacial spasm, evaluate the long-term efficacy on the quality of life and investigate prognostic factors for failure of the procedure. A retrospective study of 446 cases of hemifacial spasm treated by 511 retrosigmoid microvascular decompression over 22 years was conducted. Epidemiological, clinical and imaging findings, treatment modalities and outcomes of patients with pre- and postoperative HSF-8 quality of life questionnaire were studied. Success rate was 82% after first surgery and 91.6% after revision surgery. A low rate of perioperative morbidity was found. Facial palsy was mostly transient (5.5% transient and 0.2% permanent) and cochleovestibular deficit was seen in 4.8% of patients. Revision surgery increased nervous lesions (10.6% to 20.7%). Mean quality of life scores were significantly improved from 18 to 2 over 32, evaluated 7.3 years after surgery. Predictive factors of surgical failure were single conflicts (p = 0.041), atypical vasculo-nervous conflicts involving other vessel than postero-inferior cerebellar artery (p = 0.036), such as vein (p = 0.045), and other compression sites than root exit zone (p = 0.027). Retrosigmoid microvascular decompression is a safe and effective treatment of hemifacial spasm. Revision surgery is not to be excluded in case of failure, but does place patients at risk for more complications. Quality of life is improved in the long-term, indicating objective and subjective satisfaction.

Teflon granuloma after microvascular decompression for hemifacial spasm: a case report and literature review

Teflon has been commonly used as a surgical material. In particular, Teflon has been considered suitable for microvascular decompression of cranial nerves, as it is a stable, inert substance that does not resorb or migrate. Giant cell foreign body reactions after microvascular decompression (MVD) have been reported, but this rare complication has not been well recognized. Here, we report one case of Teflon granuloma that occurred 4 years after MVD for hemifacial spasm. We discuss the cause, histopathological analysis, particular MVD surgical methods, and management of Teflon granuloma.

Teflon granulomas mimicking cerebellopontine angle tumors following microvascular decompression

OBJECTIVES/HYPOTHESIS

To report two patients with a history of microvascular decompression (MVD) for hemifacial spasm who presented with Teflon granulomas (TG) mimicking cerebellopontine angle (CPA) tumors and to perform a systematic review of the English-language literature.

STUDY DESIGN

Case series at a single tertiary academic referral center and systematic review.

METHODS

Retrospective chart review with analysis of clinical, radiological, and histopathological findings. Systematic review using PubMed, Embase, MEDLINE, and Web of Science databases.

RESULTS

Two patients with large skull base TGs mimicking CPA tumors clinically and radiographically were managed at the authors' institution. The first presented 4 years after MVD with asymmetrical sensorineural hearing loss, multiple progressive cranial neuropathies, and brainstem edema due to a growing TG. Reoperation with resection of the granuloma confirmed a foreign-body reaction consisting of multinucleated giant cells containing intracytoplasmic Teflon particles. The second patient presented 11 years after MVD with asymmetrical sensorineural hearing loss and recurrent hemifacial spasm. No growth was noted over 2 years, and the patient has been managed expectantly. Only one prior case of TG after MVD for hemifacial spasm has been reported in the English literature.

CONCLUSIONS

TG is a rare complication of MVD for hemifacial spasm. The diagnosis should be suspected in patients presenting with a new-onset enhancing mass of the CPA after MVD, even when performed decades earlier. A thorough clinical and surgical history is critical toward establishing an accurate diagnosis to guide management and prevent unnecessary morbidity. Surgical intervention is not required unless progressive neurologic complications ensue.

LEVEL OF EVIDENCE

4 Laryngoscope, 127:715-719, 2017.

Teflon Might Be a Factor Accounting for a Failed Microvascular Decompression in Hemifacial Spasm: A Technical Note

BACKGROUND

Although Teflon is widely adopted for microvascular decompression (MVD) surgery, it has never been addressed for failure analysis. This study analyzed the reasons for failed MVDs with emphasis on the Teflon sponge.

METHODS

Among the 685 hemifacial spasm cases between 2010 and 2014, 31 were reoperated on within a week because of unsatisfactory outcome, which was focused on in this study. Intraoperative findings regarding Teflon inserts of these repeat MVDs were reviewed.

RESULTS

Among the 38 without satisfactory outcomes, 31 underwent repeat MVDs, and they were all spasm free afterwards. Eventually, the final cure rate was 99.2%. It was found in the repeat MVDs that the failure was attributable to the Teflon insert in most of the cases (74.2%) directly or indirectly. It was caused by improper placement (47.8%), inappropriate size (34.8%) and unsuitable shape (17.4%) of the Teflon sponge.

CONCLUSION

Although it is not difficult for an experienced neurosurgeon to discover a neurovascular conflict during the MVD process, the size, shape and location of the Teflon sponge should not be ignored. Basically, the Teflon insert is used to keep the offending artery away from the facial nerve root rather than to isolate it. Therefore, the ideal Teflon sponge should be just small enough to produce a neurovascular separation.

The strategy of microvascular decompression for hemifacial spasm: how to decide the endpoint of an MVD surgery

OBJECTIVE

Microvascular decompression (MVD) has become the standard treatment for hemifacial spasm. As not all patients get complete relief, this strategy is still controversial. The study aimed to figure out how to tell the proper endpoint to the surgery.

METHODS

A series of 356 consecutive patients with hemifacial spasm were enrolled in this study. All patients fell into two groups according to the period they presented. Two different criteria (simple criterion vs. complex criterion) to end an operation were applied respectively. The intra-operative finding, results and complications of these two groups were compared. The advantage of the complex criterion was analyzed.

RESULTS

The group which used complex criterion got better results than the group which used simple criterion. The complex criterion which combines full-length evidence, vascular evidence and electrophysiological evidence proved to be reliable to tell the proper endpoint to the surgery.

CONCLUSION

MVD operations can be ended only after the full-length evidence, vascular evidence and electrophysiological evidence are all present.

Combined intraoperative monitoring of abnormal muscle response and Z-L response for hemifacial spasm with tandem compression type

BACKGROUND

Multiple neurovascular compression is present in about 38 % cases of hemifacial spasm (HFS). In these cases, the vertebral artery (VA) compresses another vessel, which in turn compresses the nerve. This type was named as "the tandem type". In the tandem type, the real offending vessel is often concealed by the VA. It is sometimes neglected by the surgeons. In this study, we report our experience in using abnormal muscle response (AMR) and ZL-Response (ZLR) simultaneously as intraoperative monitoring for MVD surgery of HFS with "the tandem type" vascular compression involving VA.

METHODS

Fourteen "tandem type" patients treated with microvascular decompression surgery (MVD) surgery were included. ZLR and AMR were recorded simultaneously to identify the offending vessels in operation.

RESULTS

After MVD surgery, 13 patients achieved excellent resolution of spasm. In one case, the patient failed to attain resolution in the first operation, underwent early reoperation and had good resolution. There were no operative deaths or serious operative complications. In all 14 cases, we found that VA compressed the anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA), which in turn compressed the root exit zone (REZ). A typical ZLR was identified from the AICA or PICA but not from the VA. AMR was absent in one case and persisted in one case. After the VA was transposed, the typical AMR was unchanged, unstable or disappeared, and ZLR from the AICA/PICA also existed. AMR and ZLR did not disappear until AICA/PICA was sufficiently decompressed.

CONCLUSIONS

The combination of AMR and ZLR provides more useful information than does the AMR alone, and ZLR may be the only useful intraoperative monitoring for MVD surgery in times when AMR is absent or persists. ZLR played a crucial role in finding the real offending vessel, which was often concealed by the VA in tandem type.

Surgical treatment of hemifacial spasm with zone-4 offending vessel

BACKGROUND

Increasing evidence shows that vascular compression on any of the four zones of facial nerve may cause hemifacial spasms. Vascular compression on zone 4 (the cisternal portion) of the nerve is quite common, but only a very small percentage of such compression will elicit hemifacial spasm, because zone 4 is less susceptible than zone 3 (the root exit zone). Therefore, it seems difficult for the neurosurgeons to distinguish the real culprit vessels in zone 4. Here, our experience in treating vascular compression located in zone 4 of the facial nerve is reported.

METHODS

Twelve patients of HFS due to compression of zone 4 were treated with microvascular decompression (MVD) surgery with the aid of combined monitoring of abnormal muscle response (AMR) and Z-L response (ZLR).

RESULTS

All of the 12 patients had a zone 4 compression. In addition, there were vascular compressions on zone 3 (the root exit zone) and/or zone 2 (the attached segment) in six cases. AMR was absent in two cases, unstable in one case, and persisted after vascular decompression in another one case. ZLR was stable before decompression of zone 4 and disappeared after decompression in all cases. After MVD surgery, 11 patients were cured and one patient achieved good resolution of spasm. One patient had postoperative transient tinnitus.

CONCLUSIONS

The neurosurgeon should not ignore vascular compression at zone 4, especially when compressions at zones 2 and 3 co-exist. With the aid of AMR and ZLR, we are able to judge whether offending vessels exist at zone 4.

A "sling swing transposition" technique with pedicled dural flap for microvascular decompression in hemifacial spasm

BACKGROUND

The key to successful microvascular decompression of the neurovascular compression syndrome is maintaining the separation between the nerve and the offending vessel.

OBJECTIVE

We describe a transposition technique in which a local pedicled dural flap, fashioned from the petrous posterior surface, is used to retract the offending vessel away from the root exit zone of the facial nerve in hemifacial spasm cases.

METHODS

We conducted a retrospective review of microvascular decompression operations in which the offending vessel was transposed and then retained by a local pedicled dural flap made from the dura of the petrous posterior surface.

RESULTS

This technique was used in 7 consecutive cases of the most recently operated series. Postoperatively, complete symptom relief was achieved in 100% of the patients without any significant surgical complications.

CONCLUSION

To our knowledge, this is the first report in which an autologous anatomic structure in the cerebellopontine angle, such as petrous dura mater, is used in the microvascular decompression of the facial nerve. This is a simple yet robust method and can be considered an option for the treatment of hemifacial spasm caused by arterial compression.

Delayed recurrence of hemifacial spasm after successful microvascular decompression: follow-up results at least 5 years after surgery

BACKGROUND

Microvascular decompression (MVD) for hemifacial spasm (HFS) is regarded as the gold-standard treatment due to its efficacy and durability. However, some patients still suffer from delayed recurrence after initially successful MVD.In this study, we describe our clinical experience in a single institute following up initially successful MVD for HFS 5 or more years after surgery. We analyzed the probability of, risk/predisposing factors for, and timing of delayed recurrence.

METHODS

We retrospectively reviewed data from 587 patients meeting our inclusion criteria who underwent MVD for HFS from March, 1999, to June, 2006. We evaluated the time-dependent probability of recurrence and factors affecting delayed recurrence and time of recurrence.

RESULTS

The probability of delayed recurrence was 1.0, 1.7, and 2.9 % at 1 year, 2 years, and 5 years after surgery, respectively. Mean time to recurrence was 153.1 months (95 % confidence interval [151.4-154.9]). The probability of late recurrence was increased in patients with co-morbid arterial hypertension (p = 0.036). However, there was a trend towards an association of delayed recurrence with co-existence of young age, male gender, vein or VA offender, and experience of transient facial weakness.

CONCLUSIONS

Delayed recurrence of HFS after initially successful MVD is rare; however, there are patients who experience delayed recurrence more than 2 years after MVD, even until 5 years after MVD. Our results suggest that arterial hypertension contributes to late recurrence. We did not find a statistically significant relationship between recurrence and other putative risk/predisposing factors.

Discovery of a new waveform for intraoperative monitoring of hemifacial spasms

BACKGROUND

Surgeons often rely on intraoperative electrophysiological monitoring to determine whether decompression is sufficient during microvascular decompression surgery for hemifacial spasms. A new monitoring method is needed when an abnormal muscle response is occasionally not available or is unreliable. This study was an observational clinical trial exploring a new waveform recorded from the facial muscles while the offending artery wall was electrically stimulated.

METHODS

Thirty-two patients with typical hemifacial spasm and 12 with trigeminal neuralgia as a control were included. The facial muscle response was recorded during microvascular decompression surgery while the offending artery wall was stimulated (2 mA × 0.2 ms). The latency, amplitude, and effective refractory period were analyzed.

RESULTS

A waveform was recorded from the facial muscles of patients with hemifacial spasm when the offending artery wall was stimulated and was named the "Z-L response." The latency was 7.3 ± 0.8 ms, the amplitude was 0.08 ± 0.02 mV, and the effective refractory period was 3.5-4 ms. The Z-L response disappeared immediately after microvascular decompression. No waveform was recorded from the facial muscles of patients with trigeminal neuralgia while the anterior inferior cerebellar artery, which adheres to the facial nerve, was stimulated (2 mA × 0.2 ms).

CONCLUSION

We found a new waveform for intraoperative monitoring of hemifacial spasm. The Z-L response was useful when the abnormal muscle response was absent before decompression or persisted after all vascular compressions were properly treated. Particularly, the Z-L response may help neurosurgeons determine the real culprit when multiple offending vessels exist.

Surgical treatment of pediatric hemifacial spasm patients

PURPOSE

To study the clinical features and outcomes of pediatric primary hemifacial spasm patients who underwent microvascular decompression procedures.

METHODS

In this retrospective study, five pediatric (<18 years old) primary hemifacial spasm patients underwent microvascular decompression. After surgery, resolution of spasms and surgical complications were observed. Their social adaptability was evaluated using a social adaptation scale, which was designed specially for Chinese middle-school students.

RESULTS

Four typical hemifacial spasm patients had immediate excellent or good relief. However, the microvascular decompression procedure did not help the atypical patient much (50% relief of spasm). The score of social adaptation of the pediatric hemifacial spasm patients was 111.6  ±  8.2. Compared with the ordinary healthy Chinese middle-school students, whose score is 170.8  ±  25.4, the patients experienced great difficulty in social adaptation (P  <  0.01). After surgery, the scores of two patients increased to a normal level; however, the other three patients remained unchanged.

CONCLUSIONS

Microvascular decompression is effective and safe to typical primary hemifacial spasm patients younger than 18 years old. Hemifacial spasm is harmful to the children's social adaptation. However, only some of the patients recovered to the normal social adaptation level even when the spasms were cured.

Re-operation for persistent hemifacial spasm after microvascular decompression with the aid of intraoperative monitoring of abnormal muscle response

BACKGROUND AND OBJECTIVES

Microvascular decompression (MVD) is the only solution that can effectively control hemifacial spasm (HFS). Regarding treatment of the patients who failed the first operation, it is still controversial. We tried to evaluate the safety and efficiency of the early re-exploration for such kinds of patients.

METHODS

Thirteen patients failed the first MVD and received a second MVD procedure. The spasm was not resolved at all or became even more severe after the first MVD. Abnormal muscle response (AMR) persisted during the first MVD operation or disappeared once but emerged again. The patient had a strong will to do the re-operation and was aware of the high risks of operative complications.

RESULTS

All the 13 patients got good or excellent spasm resolution immediately after the re-operation, which involved whole-range exploration and intraoperative AMR monitoring; however, there were two cases (15.4%) of permanent facial weakness and three cases (23.0%) of transient facial weakness.

CONCLUSIONS

Our experience on early repeat MVD is whole-range exploration and intraoperative AMR monitoring; in other words, re-operation cannot rely too much on experience.

Review and update of involuntary facial movement disorders presenting in the ophthalmological setting

We review the existing literature on the involuntary facial movement disorders-benign essential blepharospasm, apraxia of eyelid opening, hemifacial spasm, and aberrant facial nerve regeneration. The etiology of idiopathic blepharospasm, a disorder of the central nervous system, and hemifacial spasm, a condition involving the facial nerve of the peripheral nervous system, is markedly different. We discuss established methods of managing patients and highlight new approaches.

Unusual causes and presentations of hemifacial spasm

OBJECTIVE

To evaluate unusual possible causes and clinical presentations of hemifacial spasm (HFS).

METHODS

The authors reviewed 1642 cases of HFS. Assessments were based on clinical features, 3-dimensional time-of-flight magnetic resonance angiography, and surgical findings. Causes other than neurovascular compression at the root exit zone of the facial nerve were investigated and unusual clinical presentations were noted.

RESULTS

Nine (0.5%) patients had a secondary causative structural lesion, 7 patients had a tumor, and the remaining 2 had a vascular malformation. Direct compression by dolichoectatic vertebrobasilar artery was noted in 12 (0.7%) patients. In 7 (0.4%) patients, only the distal portion of the facial nerve was compressed, and five (0.3%) had only venous compression. Bilateral HFS and tic convulsif were encountered in 7 (0.4%) and 6 (0.37%) patients, respectively. Fifty-six (3.4%) patients were younger than 30 years old at the time of microvascular decompression.

CONCLUSION

HFS can result from tumor, vascular malformation, and dolichoectatic artery. Therefore, appropriate preoperative radiological investigations are crucial to achieve a correct diagnosis. The authors emphasize that distal compression or only venous compression can be responsible for persistent or recurrent symptoms postoperatively. In cases of bilateral HFS, a definite differential diagnosis is necessary for appropriate therapy. MVD is recommended as the treatment of choice in patients younger than 30 years old or patients with painful tic convulsif.

Hemifacial spasm: a neurosurgical perspective

Hemifacial spasm (HFS) is characterized by tonic clonic contractions of the muscles innervated by the ipsilateral facial nerve. Compression of the facial nerve by an ectatic vessel is widely recognized as the most common underlying etiology. HFS needs to be differentiated from other causes of facial spasms, such as facial tic, ocular myokymia, and blepharospasm. To understand the overall craniofacial abnormalities and to perform the optimal surgical procedures for HFS, we are to review the prevalence, pathophysiology, differential diagnosis, details of each treatment modality, usefulness of brainstem auditory evoked potentials monitoring, debates on the facial EMG, clinical course, and complications from the literature published from 1995 to the present time.

What is new in the era of focal dystonia treatment? Botulinum injections and more

PURPOSE OF REVIEW

The treatment options for the management of dystonias continue to evolve and improve. Clinical outcomes, however, are not predictably consistent using a single treatment regimen in all patients.

RECENT FINDINGS

Botulinum toxin is still considered the best treatment option for the treatment of focal dystonias: blepharospasm, hemifacial spasm, and apraxia of eyelid opening. New findings indicate that physicians may be a little more aggressive with the dosage when the disease progresses. A new formulation of botulinum toxin has been produced that includes no proteins and may address the immunoresistance that can occur with prolonged use. Additional systemic medications may be helpful as adjuncts only in selected cases. Improved surgical techniques are now more successful and cause fewer complications. Therefore, many refractory cases are now offered a surgical approach alone or in combination with botulinum toxin.

SUMMARY

There have been recent therapeutic developments in the treatment of ocular dystonias.