Safety and effectiveness of microvascular decompression for treatment of hemifacial spasm: a systematic review

Determining prognostic factors in the treatment of primary hemifacial spasm: Clinical outcomes and complications. A literature review

Objective

Primary Hemifacial Spasm (PHFS) significantly impacts quality of life, necessitating effective treatment like microvascular decompression of the facial nerve. This study aims to identify prognostic factors related to surgical treatment to enhance outcomes and minimize complications. A systematic review of literature from the past five years was conducted.

Methods

Following PRISMA guidelines, we systematically searched databases like PubMed, Embase, Scopus, Ovid, EBSCO, and Cochrane using keywords such as 'Hemifacial spasm,' 'Microvascular decompression,' 'Neurovascular conflict,' and 'Surgical techniques.' The search spanned January 2018 to November 2023. The 'Rayyan' program facilitated data compilation. Each author reviewed abstracts, applying inclusion criteria like systematic reviews, clinical trials, observational studies, and case series, while excluding theoretical or non-English articles.

Results

Of 26 selected articles, those solely addressing PHFS treatment with botulinum toxin and lacking surgical procedure data were excluded. Thus, our analysis focused on 16 articles, including meta-analyses, systematic reviews, clinical trials, and observational studies.

Discussion

Microvascular decompression at the cerebellar pontine angle is the mainstay treatment for hemifacial spasm. Despite limited statistically significant prognostic factors in the literature, overarching recommendations aim to improve outcomes, minimize complications, and prevent recurrences. Key considerations include surgeon expertise, precise techniques, thorough nerve exploration, identifying the conflict's cause, and intraoperative monitoring.

Conclusions

PHFS significantly impacts patients' lives, necessitating timely surgical intervention if initial treatments fail. While statistically significant prognostic factors may be lacking, this study highlights crucial considerations for successful treatment.

Primary hemifacial spasm: anatomical insights

BACKGROUND

Primary Hemifacial Spasm (pHFS) is a disorder caused by compression of vessels on the root of the facial nerve. There has been conflicting evidence regarding the side of the face that is more frequently affected. Moreover, it has been found in several studies that women are afflicted by approximately twice as many as men.

OBJECTIVES

We reviewed the literature to explain HFS tendencies from an anatomical aspect. We wanted to see whether there are anatomical variations that can increase the risk of developing HFS or underlie its tendency to a specific gender and side of the face.

METHODS AND MATERIAL

A PubMed search was done for the articles on "Hemifacial Spasm" published in English literature, and we selected the articles regarding the significant anatomical differences in HFS patients.

RESULTS

AICA proximal branching pattern, highly originated PICA, VA dominancy, and VA deviation are among the predisposing anatomical variances. Overall, both sides of the face are equally affected in HFS. However, there are side preferences based on the causative vessels, which may be due to differences in the anatomical features of the left and right side vessels.

CONCLUSIONS

Various anatomical variations regarding posterior circulation can increase the risk of HFS. Recent evidence suggests whether there is no side dominance or a tendency exists toward the left side. There is no comprehensive explanation for precise reasons underlying the tendency of HFS to affect women. Evidence regarding anatomical variations of the posterior circulation comparing men and women with HFS is scarce, and further studies are required.

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.

Hemifacial spasms triggered by compression of tortuous anterior inferior cerebellar artery loop on the facial nerve in the internal auditory canal: A case report

RATIONALE

Hemifacial spasm (HFS) is triggered by neurovascular compression mostly at the root entry/exit zone of the facial nerve. HFS with the responsible blood vessel located in the internal auditory canal (IAC) is a very rare occurrence. In our case, the HFS was triggered by compression of the anterior inferior cerebellar artery (AICA) loop on the facial nerve in the IAC.

PATIENT CONCERNS

A 27-year-old female presented with a 5-year history of right-sided facial twitching with no obvious course. The frequency and severity of the attacks increases when the patient was anxious or agitated which severely affected her quality of life.

DIAGNOSIS

Preoperative 3D-TOF magnetic resonance imaging (MRI) evaluation of cranial nerves showed that the right AICA loop had a tortuous course within the IAC and compressed the facial nerve.

INTERVENTION

Microvascular decompression (MVD) surgery was carried out to separate the tortuous AICA loop and facial nerve in the IAC using a Teflon pad.

OUTCOMES

The abnormal muscle response disappeared intraoperatively and 2-years follow-up revealed no recurrence of her symptomatology. She is current well and go about her daily activities with no neurological deficits.

LESSON

The attachment of the facial nerve to the tortuous AICA loop coupled with the pulsatile impulse of tortuous AICA loop may have resulted in the entrapment and compression of the CN VII in the IAC.

Transcutaneous electrical acupoint stimulation to prevent dizziness after microvascular decompression for hemifacial spasm: A randomized controlled trial

BACKGROUND

Dizziness often occurs after microvascular decompression (MVD), and therapeutic options are limited. The aim of this trial was to determine the potential efficacy of transcutaneous electrical acupoint stimulation (TEAS), against dizziness and its safety in patients undergoing MVD.

METHODS

Adult patients scheduled to undergo MVD for hemifacial spasm under total intravenous anesthesia were randomized at a 1:1 ratio to receive, after extubation, 30-min TEAS in the mastoid region as well as Fengchi acupoints (GB20) and Neiguan acupoints (PC6) or 30-min sham stimulation. The primary outcome was the incidence of dizziness at 2 h after surgery. Secondary outcomes included dizziness, postoperative nausea and vomiting (PONV) or headache severity, rescue medication, changes in intraocular pressure before and after surgery, length of stay, dizziness symptoms 4 weeks after discharge, and surgical complications.

RESULTS

A total of 86 patients (51.9 ± 9.4 years of age; 67 women) were enrolled. One patient (in the TEAS arm) was excluded from analysis due to conversion to sevoflurane anesthesia. The rate of dizziness at 2 h after surgery was 31.0 % (13/42) in the TEAS arm vs. 53.5 % (23/43) in the sham control arm (P = 0.036). TEAS was also associated with significantly lower severity of dizziness, based on a 10-point scale, during the first 24 h after surgery. None of the other secondary efficacy outcomes differed significantly between the two arms. All postoperative complications were Clavien-Dindo grade I or II. The rate of postoperative complications was 21.4 % (9/42) in the TEAS arm vs. 16.3 % (7/43) in the sham control arm (P = 0.544).

CONCLUSIONS

Compared with sham control, TEAS was associated with a lower incidence of dizziness within 2 h and lower severity of dizziness within 24 h post-operatively, but no improvement in other outcomes, in adult patients undergoing MVD for hemifacial spasm.

Infrafloccular approach effectively prevents hearing complication in microvascular decompression surgery for hemifacial spasm

OBJECTIVE

The infrafloccular approach in microvascular decompression (MVD) surgery for hemifacial spasm (HFS) was investigated for the prevention of hearing complications.

METHODS

Retrospective analysis of 136 patients who underwent MVD for HFS in 2019. The infrafloccular approach for MVD was adopted to resolve the symptom and protect hearing function. Postoperative hearing function was evaluated subjectively and objectively within 30 postoperative days, and later mainly subjectively. Postoperative condition of mastoid air cells based on the CT scan of the following day was also recorded.

RESULTS

No final postoperative subjective hearing impairment was found in all patients. Mastoid air cells were opened in 105 patients, and subjective hearing impairment was recorded in 57 patients within 30 postoperative days, but all improved later. Increases in thresholds of greater than 10 dB in air conduction were observed in 28 patients, including 26 of transient conductive hearing loss (increases in the threshold of less than or equal to 10 dB). The other 2 patients with increases in the threshold of greater than 10 dB in both air and bone conduction had improvement confirmed by later audiometry.

CONCLUSIONS

Infrafloccular approach in MVD for HFS provides a good hearing outcome. Inclusion of postoperative hearing conditions in the later period is ideal for a precise hearing evaluation.

Hemifacial spasm associated with trigeminal neuralgia secondary to trigeminal vascular compression

The coincidence in a patient of Hemifacial Spasm and Trigeminal Neuralgia is not frequent. A case is presented with the objective of showing this association due to the abnormal activation of the Trigemino-Facial Reflex. A 55-year-old woman with an 8-year history of left-sided hemifacial spasm and typical trigeminal pain in the ipsilateral V1 and V2 territory. The physical examination shows spasms in the left hemiface, with reproduction of intense pain upon sensory stimulation of the skin on the forehead and upper dental arch. The MRI showed a vessel in intimate contact with the entrance area of ​​the left trigeminal nerve. A left retrosigmoid approach was performed. First, the entrance area of ​​the trigeminal nerve was accessed, finding a clear vascular conflict, which was isolated with Teflon. Then, the trajectory was changed and the exit zone of the facial nerve was accessed, and no type of vascular conflict was identified. The patient presented complete resolution of the Hemifacial Spasm and the associated trigeminal pain. The analysis of this case allows us to conclude that during microvascular decompression of the Facial Nerve, if frank proximal compression is not evident, the Trigeminofacial structural relationship must be taken into account, making it necessary to explore the Trigeminal Nerve.

Assessment of prevalence of vascular contact of the facial nerve in asymptomatic patients using three-dimensional constructive interference in steady-state (3D CISS) MRI acquisition

Purpose

To evaluate the prevalence of vascular contact of the facial nerve in patients without hemifacial spasm or facial palsy using magnetic resonance imaging (MRI).

Material and methods

Our radiology database was accessed to find a series of consecutive adult patients who underwent MRI of the brain during the study period, excluding those with a history of hemifacial spasm (HFS), facial palsy, traumatic brain injury, intracranial tumour, intracranial surgery, trigeminal neuro-vascular compression, brain radiation therapy, and studies with poor image quality. A total of 112 (224 sides) MRIs of the posterior fossa were independently reviewed by 2 radiologists for neurovascular contact involving the facial nerve. The presence of neuro-vascular contact, the number of points of contact, the location of contact along the intracranial course of the facial nerve, the culprit vessel, and the severity of compression were recorded in the CISS MRI sequence in the cohort of patients without HFS and facial palsy.

Results

The prevalence of neurovascular contact involving the facial nerve can be as high as 51% in patients asymptomatic for HFS and facial palsy. It is frequently caused by the anterior inferior cerebellar artery and commonly involves the cisternal portion with mild to moderate severity.

Conclusions

In asymptomatic patients, the pulsatile neurovascular contact of the intracranial segment of the facial nerve typically occurs at one point, involving the distal portion with milder severity in contrast to patients with HFS. These results in the asymptomatic cohort should be considered when evaluating the candidacy of HFS patients for microvascular decompression.

Hemifacial Spasm Associated With the Specific Offending Vein

BACKGROUND AND OBJECTIVES

Hemifacial spasm (HFS) caused by venous compression is a rare occurrence. Currently, there is no relevant research on the venous characteristics and potential pathogenic mechanisms causing venous HFS. Exploring the venous characteristics in venous-type HFS may reduce the likelihood of repeated surgery.

METHODS

The authors presented 4 cases of HFS caused by veins of middle cerebellar peduncle (V. of Mid.Cer.Ped) successfully treated with microvascular decompression.

RESULTS

Based on intraoperative observations and abnormal muscle response (AMR) monitoring, it was determined that V. of Mid.Cer.Ped were offending vessels in these patients. Moreover, veins crossed between the facial and vestibulocochlear nerves, and then surrounded the ventral aspect of the facial nerve root. Microvascular decompression for the offending vessel was successfully performed, and AMR disappeared for each patient. These patients were discharged without any complications and involuntary contractions or twitching of facial muscles.

CONCLUSION

The study demonstrated that veins can indeed induce HFS. The characteristic of the V. of Mid.Cer.Ped that leads to HFS is that these veins traverse between the facial nerve and the vestibulocochlear nerve, and then surround the ventral aspect of the facial nerve root. The dynamic influence of cerebrospinal fluid leads to pulsatile impingement of the facial nerve on the vein, resulting in facial nerve bending and deformation at the location of the vein. Significantly, in the context of surgery, if it is noticed that the V. of Mid.Cer.Ped surrounds the ventral aspect of the facial nerve root and the facial nerve is compressed and deformed, when AMR disappears after decompression of the artery, it may be necessary to perform vein decompression.

Cortical changes in the brain of patients with hemifacial spasm

OBJECTIVE

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary muscle contractions on one side of the face. It is associated with disturbances in the brain's functional architecture. Despite this, the structural alterations in the brain related to HFS remain poorly understood. In this study, we investigated the cortical morphology changes in patients with HFS compared to healthy controls (HCs).

METHODS

We analyzed 3D T1-weighted MRI images from 33 patients with left-sided primary HFS and 33 age- and sex-matched HCs. Measurements of cortical thickness (CTh), sulcal depth, local gyrification index (lGI), and fractal dimension were taken using a computational anatomy toolbox. A general linear model, accounting for age, gender, and total brain volume, was applied for statistical analyses. Significant clusters were then assessed for correlations with clinical parameters.

RESULTS

The HFS patients displayed several cortical abnormalities when compared to HCs, including reduced CTh in the contralateral precentral gyrus and left orbitofrontal cortex, decreased sulcal depth in the left orbitofrontal cortex, and increased lGI in the right insula and superior temporal cortex. However, fractal dimension did not differ significantly between the groups. Additionally, in HFS patients, a notable negative correlation was found between the sulcal depth in the left orbitofrontal cortex and the Beck Depression Inventory-II scores.

CONCLUSIONS

Our findings reveal that HFS is associated with specific surface-based morphological changes in the brain. These alterations contribute to a deeper understanding of the neurophysiological mechanisms involved in HFS and may have implications for future research and treatment strategies.

Results from 228 Patients with Hemifacial Spasm Undergoing Microvascular Decompression without Intraoperative Neuroelectrophysiology Monitoring

BACKGROUND

Intraoperative neuroelectrophysiology monitoring (IONM) has been used to decrease complications and to increase the successful rate of microvascular decompression (MVD) MVD for hemifacial spasm (HFS). Still, it is not available at limited resource centers. We report the outcome of patients undergoing MVD for HFS without using IONM.

METHODS

The variables concerning the patients' demographics (age and gender), clinical characteristics, offending vessels (vertebral artery type and non-vertebral artery type), postoperative grade of HFS, and postoperative complications of HFS patients undergoing MVD were retrospectively reviewed and collected. The scoring system provided by the Japan Society for MVD was used to evaluate the postoperative outcome of HFS. Postoperative hearing ability was evaluated according to a subjective assessment of the patients.

RESULTS

A total of 228 patients were recruited. Their median age was 51.0 (44.0-57.0) years old. The total cure effect was observed in 207 (90.8%) patients within the first week after the surgery and in 200 (96.1%) patients in a 2-year follow-up. Permanent hearing disturbance happened in 2 patients (0.9%). No patient had permanent unilateral deafness (0%). No postoperative permanent facial paralysis was reported.

CONCLUSIONS

MVD without IONM may be performed safely and effectively to treat patients with HFS.

The Anterior Inferior Cerebral Artery Variability in the Context of Neurovascular Compression Syndromes: A Narrative Review

The anterior inferior cerebellar artery (AICA) is situated within the posterior cranial fossa and typically arises from the basilar artery, usually at the pontomedullary junction. AICA is implicated in various clinical conditions, encompassing the development of aneurysms, thrombus formation, and the manifestation of lateral pontine syndrome. Furthermore, owing to its close proximity to cranial nerves within the middle cerebellopontine angle, AICA's pulsatile compression at the root entry/exit zone of cranial nerves may give rise to specific neurovascular compression syndromes (NVCs), including hemifacial spasm (HFS) and geniculate neuralgia concurrent with HFS. In this narrative review, we undertake an examination of the influence of anatomical variations in AICA on the occurrence of NVCs. Significant methodological disparities between cadaveric and radiological studies (CTA, MRA, and DSA) were found, particularly in diagnosing AICA's absence, which was more common in radiological studies (up to 36.1%) compared to cadaver studies (less than 5%). Other observed variations included atypical origins from the vertebral artery and basilar-vertebral junction, as well as the AICA-and-PICA common trunk. Single cases of arterial triplication or fenestration have also been documented. Specifically, in relation to HFS, AICA variants that compress the facial nerve at its root entry/exit zone include parabola-shaped loops, dominant segments proximal to the REZ, and anchor-shaped bifurcations impacting the nerve's cisternal portion.

Evaluating magnetic resonance imaging characteristics and risk factors for hemifacial spasm

PURPOSE

The specific neurovascular compression (NVC) event responsible for the symptomatic manifestation of hemifacial spasm (HFS) remains difficult to assess accurately using magnetic resonance imaging (MRI). We aim to evaluate the MRI characteristics of HFS.

METHOD

We retrospectively included patients with HFS and divided them into a test group (n = 186) and a validation group (n = 28). The presence, severity, and offending vessel type of NVC in each portion, and the orientation of the offending vessel around the facial nerve, were recorded. Conditional logistic regression analyses were performed to evaluate correlations using test group. The validation group was used to verify whether our findings improved diagnostic performance.

RESULTS

Deformity in the proximal cisternal segment was significantly correlated with HFS occurrence (odds ratio [OR]: 256.58, p = .002), whereas contact was not (p = .233). Both contact and deformity in the root detachment point (OR: 19.98 and 37.22, p < .001 and p = .013, respectively) or attached segment (OR: 4.99 and 252.52, p = .001 and p < .001, respectively) were significantly correlated with HFS occurrence. Our findings improved specificity, positive predictive value, and accuracy of diagnosis than conventional diagnostic methods. The vertebral artery predominantly compress the facial nerve in the inferior-anterior position, the anterior inferior cerebellar artery predominantly in the inferior position, the posterior inferior cerebellar artery predominantly in the inferior position, vein predominantly in the posterior-superior position.

CONCLUSIONS

This study further demonstrates that within the susceptible portion of facial nerve, different portions of the nerve respond differently to NVC. Each offending vessel has its own preferred conflict orientation. Our study offers reference for neurosurgeons in diagnosis and treatment.

Mapping trends in hemifacial spasm research: bibliometric and visualization-based analyses of the Web of Science Core Collection

Hemifacial spasm (HFS) is a common cranial nerve disease. In HFS research, we conducted a bibliometric analysis to examine the development and research trends. A retrieval of HFS studies published between 2011 and 2022 was performed from the Web of Science Core Collection in September 2022. Two scientometric tools were used to perform bibliometric and visualization-based analyses: VOSviewer and CiteSpace. Bibliometric analysis of 1461 studies published between 2011 and 2022 was carried out using data from 444 journals, 6021 authors, 1732 institutions, and 76 countries/regions. China, the USA, Japan, and South Korea were four key contributors to this study. Shanghai Jiaotong University was the major institution with the larger number of publications. Li Shiting was the most prolific author. Jannetta PJ was the most co-cited author. World Neurosurgery was the top prolific journal. Journal of Neurosurgery was the top co-cited journal. The top five keywords were hemifacial spasm, microvascular decompression, trigeminal neuralgia, surgery, and neurovascular compression. This study examines the research trends in global scientific research on HFS over the last decade. Researchers interested in learning more about current trends and novel research frontiers in this area can benefit from the study.

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.

Outcomes after Microvascular Decompression for Hemifacial Spasm without Definite Radiological Neurovascular Compression at the Root Exit Zone

The purpose of this study was to investigate the outcome of microvascular decompression (MVD) in patients with hemifacial spasm (HFS) who have no definite radiological neurovascular compression (NVC). Sixteen HFS patients without radiological NVC on preoperative MRI underwent MVD surgery. The symptoms were left-sided in fourteen (87.5%) and right-sided in two patients (12.5%). Intraoperatively, the most common vessel compressing the facial nerve was the AICA (8, 44.4%), followed by arterioles (5, 27.8%), veins (4, 22.2%), and the PICA (1, 5.6%). The most common compression site was the cisternal portion (13, 76.5%) of the facial nerve, followed by the REZ (4, 23.5%). One patient (6.3%) was found to have multiple NVC sites. Arachnoid type (7, 50%) was the most common compressive pattern, followed by perforator type (4, 28.6%), sandwich type (2, 14.3%), and loop type (1, 7.1%). A pure venous compression was seen in two patients, while a combined venous-arterial "sandwich" compression was detected in two patients. Symptom improvement was observed in all of the patients. Only one patient experienced recurrence after improvement. Based on our experience, MVD surgery can be effective for primary HFS patients with no definite radiological NVC. MVD can be considered if the patient shows typical HFS features, although NVC is not evident on MRI.

Penetrating Offenders in Hemifacial Spasm: Surgical Tactics and Prognosis

(1) Background: In cases of hemifacial spasm (HFS), there are various patterns related to the vascular compression of the facial nerve, including a very rare form that is seen when the offending vessel penetrates the facial nerve. However, there have been few reports in the literature regarding the associated surgical techniques and postoperative prognosis. (2) Methods: A retrospective review was conducted of 4755 patients who underwent microvascular decompression (MVD) surgery from April 1997 to June 2023. In total, 8 out of the 4755 patients (0.2%) exhibited a penetrating offending vessel; the medical and surgical records of these 8 patients were then analyzed. Surgery was then attempted to maximally decompress the penetrating offender. (3) Results: Seven out of the eight patients (87.5%) were spasm-free immediately after surgery, and one had only 10% residual spasm compared to their preoperative condition. That patient was also spasm-free one year later. Postoperative facial palsy occurred in one patient (12.5%) who was assessed as grade II in the House-Brackmann grading system. In another patient, the resection of a small facial nerve bundle did not result in facial palsy. There were no cases of hearing loss or other complications. (4) Conclusions: Decompressing the penetrating offender did not increase the incidence of facial palsy, and the prognosis for hemifacial spasms was good. Therefore, when a penetrating pattern was encountered during MVD surgery, decompression between the penetrating offender and the facial nerve may offer good results.

Influence of Minimum Alveolar Concentration and Inhalation Duration of Sevoflurane on Facial Nerve Electromyography in Hemifacial Spasm: A Randomized Controlled Trial

BACKGROUND

The lateral spread response (LSR) is an electromyography feature of hemifacial spasm; intraoperative reduction in the LSR is associated with positive surgical outcomes. This study examined the effects of different minimum alveolar concentrations (MACs) and durations of sevoflurane inhalation on the LSR.

METHODS

Eighty patients undergoing microvascular decompression surgery for hemifacial spasm were randomly allocated to receive propofol-remifentanil total intravenous anesthesia alone or in combination with sevoflurane at 0.5, 0.75, or 1 MAC. The LSR and orbicularis oculi muscle wave were recorded before and at 15 and 30 minutes after the start of sevoflurane administration.

RESULTS

Sevoflurane reduced the LSR amplitude in a dose-dependent and duration-dependent manner. The curve representing the LSR amplitude preservation ratio change according to sevoflurane concentration is best fitted by regression analysis using a cubic model, as the cubic equations had the largest coefficient of determination; at 15 minutes ( R2 =0.76, F =78.36, P <0.05) and at 30 minutes ( R2 =0.882, F =189.94, P <0.05). The inhibitory effect of sevoflurane on the LSR amplitude was greater in the first 15 minutes than in the second 15 minutes of sevoflurane administration. Sevoflurane at 1 MAC for 30 minutes mildly decreased the amplitude of the orbicularis oculi muscle wave. The latencies of the LSR and the orbicularis oculi muscle wave were not affected by sevoflurane at all MACs studied.

CONCLUSIONS

The combination of intravenous propofol-remifentanil anesthesia with 0.5 MAC sevoflurane allows reliable intraoperative LSR monitoring in hemifacial spasm patients. Our findings support the central rather than peripheral hypothesis of the LSR.

Clinical Profile of Patients with Hemifacial Spasm at a Tertiary Eye Care Center in South India: A Retrospective Study

Purpose

To assess the incidence and clinical profile of hemifacial spasm (HFS) and the association between HFS and systemic diseases.

Methods

This retrospective study was carried out on 85 patients with HFS, presenting at a tertiary eye care center in South India. Demographic and clinical details were recorded for all patients. Of these, the patients who had undergone magnetic resonance imaging (MRI) of the brain were analyzed for primary and secondary HFS.

Results

The mean age of the patients was 56.11 ± 12.51 years. The age at onset of HFS was 54.9 ± 12.7 years. The disease duration was 9.51 ± 7.28 years. Male:female ratio was 1:1.17. The right side was involved in 31 patients (36.47%) and the left side in 54 patients (63.52%). MRI was performed in 54 (63.52%) patients and showed neurovascular conflict in 22 (40.74%) patients and space-occupying lesions in 2 (3.70%) patients. Forty-nine (57.64%) patients had primary HFS, while five (5.88%) patients had secondary HFS due to old facial palsy in 3 and space-occupying lesions in two patients. Twenty (23.52%) patients received botulinum toxin A with a good response. Type of HFS had a significant association with hypertension (P = 0.046) while no significant association was present between laterality of HFS and systemic diseases (P > 0.05 each). Multivariate analysis showed a marginally significant association between type of HFS and hypertension (P = 0.057).

Conclusions

Primary HFS was the main type of HFS with female dominance and predilection for the left side. Hypertension had a relationship with HFS that needs to be investigated further for its causal nature.

Microvascular decompression for hemifacial spasm: Complications after 292 procedures without neurophysiological monitoring

Background

Hemifacial spasm (HFS) is characterized by involuntary, progressive, and intermittent spasms in the upper and lower facial muscles. Due to the high success rate, microvascular decompression (MVD) is the treatment of choice, and intraoperative neuromonitoring (INM) is considered useful for achieving safe surgery. Still, most centers do not have this technology.

Methods

We analyzed 294 patients with HFS treated with MVD without INM. We only included patients with a neurovascular etiology while excluding other causes, such as tumors. As part of the postoperative evaluation, we assessed preoperative magnetic resonance imaging and pure-tone audiometry.

Results

The main complication was peripheral facial paralysis in 50 patients, followed by hypoacusis in 22 patients and deafness in 17 patients, associated with a failed surgical outcome (P = 0.0002). The anterior inferior cerebellar artery (AICA) was an offending vessel, and the involvement of more than one vessel was significantly associated with the development of facial nerve palsy (P = 0.01). AICA was also associated with hearing impairment (P = 0.04). Over 90% of immediate complications improve in the follow-up (6 months), and one patient did not show a cure for initial HFS.

Conclusion

MVD is the method with the highest long-term cure rates for treating HFS; however, we must inquire into the multiple factors of the patient and the surgeon to predict surgical outcomes. INM is not a must during MVD for HFS. We recommend its use depending on the availability and mainly on the surgeon's skills, for surgeons.

Operative Findings of over 5000 Microvascular Decompression Surgeries for Hemifacial Spasm: Our Perspective and Current Updates

Hemifacial spasm (HFS) is a hyperactive cranial neuropathy, and it has been well established that the cause of primary HFS is compression on the root exit zone (REZ) of the facial-vestibulocochlear nerve complex (CN VII-VIII) by a vessel or vessels. MVD is the only curative treatment option for HFS with a high success rate and low incidence of recurrence and complications. We categorize six classical compressive patterns on the REZ as well as five challenging types. Knowledge of these patterns may help in achieving a better surgical outcome.

The Efficacy of Scalp Nerve Block in Postoperative Pain Management after Microvascular Decompression: A Randomized Clinical Trial

The scalp nerve block, created by injecting local anesthetics around the scalp nerves, is reported to effectively reduce pain after surgery. In this study, we evaluated the efficacy of scalp nerve block in patients with hemifacial spasm (HFS) undergoing microvascular decompression (MVD). Seventy-four patients who underwent MVD for HFS were enrolled. The block group received scalp nerve block with 0.5% ropivacaine before surgery. The primary outcome was cumulative dose of rescue analgesics 24 h postoperatively. The secondary outcomes were included pain scores, postoperative antiemetic consumption, and Quality of Recovery-15 scale. The cumulative dose of rescue analgesics at 24 h postoperatively was not significantly different between the two groups (4.80 ± 3.64 mg vs. 5.92 ± 3.95 mg, p = 0.633). However, the pain score was significantly reduced in the block group at 6, 12, and 24 h postoperatively. Postoperative antiemetic consumption was lower in the block group than the control group at 12 h. There were no significant differences between the two groups for other secondary outcomes. In MVD for HFS, a preoperative scalp nerve block might reduce postoperative pain in the early postoperative period, but a larger study using a multimodal approach is needed to confirm the efficacy of a scalp block.

Correlation of Preoperative High-Resolution Neurovascular Imaging and Surgical Success in Neurovascular Compression Syndromes

BACKGROUND

Neurovascular compression syndromes (NVCSs) are a group of neurological disorders characterized by compression of a cranial nerve and include trigeminal neuralgia (TN), hemifacial spasm, geniculate neuralgia, glossopharyngeal neuralgia, vestibular paroxysmia, and trochlear palsy. The European Academy of Neurology recommends constructive interference in steady-state/fast imaging employing steady-state (CISS/FIESTA) magnetic resonance imaging (MRI) in the evaluation of medically intractable TN, but similar recommendations do not exist for the remaining NVCSs.

METHODS

We conducted a retrospective chart review of 300 patients with an NVCS who underwent microvascular decompression (MVD) by a single neurosurgeon from 2004 to 2021. Data were collected on preoperative diagnosis, pre- and postoperative symptoms, presence/absence of preoperative high-spatial-resolution CISS/FIESTA MRI, and intraoperative findings. Rates of symptomatic improvement were used as a correlate of surgical success.

RESULTS

The rate of symptomatic improvement in the patients with a preoperative CISS/FIESTA MRI was 5.8% greater than those without preoperative high-spatial-resolution neuroimaging (98.8% vs. 93%, respectively; P = 0.008). Stratified by diagnosis, patients with TN had the greatest difference in surgical success between the 2 groups (99.3% vs. 92.9%, n = 268; P = 0.006). No statistically significant differences were observed in the other NVCSs, although positive trends were noted.

CONCLUSIONS

Preoperative CISS/FIESTA MRI correlated with greater rates of surgical success in cases of medically intractable TN; however, definitive conclusions could not be made regarding the remaining NVCSs. We support the recommendation that this imaging modality be included as part of the standard of practice for the evaluation and management of TN and encourage future studies to further elucidate this relationship for the less common NVCSs using a larger cohort.

Routine postoperative admission to the neurocritical intensive care unit after microvascular decompression: necessary or can it be abandoned?

Postoperative neurocritical intensive care unit (NICU) admission of patients who underwent craniotomy for close observation is common practice. In this study, we performed a comparative analysis to determine if there is a real need for NICU admission after microvascular decompression (MVD) for cranial nerve disorders or whether it may be abandoned. The present study evaluates a consecutive series of 236 MVD surgeries performed for treatment of trigeminal neuralgia (213), hemifacial spasm (17), vagoglossopharyngeal neuralgia (2), paroxysmal vertigo (2), and pulsatile tinnitus (2). All patients were operated by the senior surgeon according to a standard protocol over a period of 12 years. Patients were admitted routinely to NICU during the first phase of the study (phase I), while in the second phase (phase II), only patients with specific indications would go to NICU. While 105 patients (44%) were admitted to NICU postoperatively (phase I), 131 patients (56%) returned to the ward after a short stay in a postanaesthesia care unit (PACU) (phase II). Specific indications for NICU admission in phase I were pneumothorax secondary to central venous catheter insertion (4 patients), AV block during surgery, low blood oxygen levels after extubation, and postoperative dysphagia and dysphonia (1 patient, respectively). There were no significant differences in the distribution of ASA scores or the presence of cardiac and pulmonary comorbidities like congestive heart failure, arterial hypertension, or chronic obstructive pulmonary disease between groups. There were no secondary referrals from PACU to NICU. Our study shows that routine admission of patients after eventless MVD to NICU does not provide additional value. NICU admission can be restricted to patients with specific indications. When MVD surgery is performed in experienced hands according to a standard anaesthesia protocol, clinical observation on a neurosurgical ward is sufficient to monitor the postoperative course. Such a policy results in substantial savings of costs and human resources.

Common trunk anomaly of the anterior and posterior inferior cerebellar artery in hemifacial spasm

BACKGROUND

The common trunk anomaly of the anterior and posterior inferior cerebellar artery (APC) is a variant artery that causes a hemifacial spasm (HFS). The anatomical characteristics include a large diameter of the trunk and the existence of the bifurcation near the facial nerve root entry zone (REZ). Despite APC being encountered at a constant rate in microvascular decompression (MVD), the anatomical and technical issues of transposing APC have not been entirely focused on yet.

METHODS

We reviewed our 68 cases with APC involvement. Patient background, radiological findings, and operative video recordings were reviewed retrospectively. The location of the bifurcation of APC and the distribution of perforators were investigated. Surgical outcomes were assessed in the long term.

RESULTS

APC involvement was diagnosed preoperatively in all cases by careful observation with MRI. Three-dimensional images determined the anatomical characteristics of APC and depicted the relationship with the facial nerve. All patients had a bifurcation close to the root entry zone that was required to transpose, including the common trunk and the distal branches, to achieve sufficient decompression. While adequate transposition from the REZ was accomplished in most cases, it was difficult to complete transposition due to short perforators in 6 patients (8.8%), resulting in interposition. Fifty-three patients (77.9%) became spasm free immediately after surgery, 66 patients (97.1%) were after 6 months, and all patients (100%) became spasm free within a year. Spasm-free status was maintained during the follow-up period (4.7 years) in all patients except one in whom facial spasm recurred 2 years after the initial surgery.

CONCLUSIONS

Transposing the common trunk with the bifurcation and distal branches contributes to obtaining favorable surgical outcomes in APC-related HFS.

A Case Report of Hemifacial Spasm Caused by Vestibular Schwannoma and Literature Review

BACKGROUND

Most cases of hemifacial spasm result from mechanical compression at the root exit zone of the facial nerve by vascular loops, and only a few cases are caused by vestibular schwannoma.

CASE PRESENTATION

We report a case of symptomatic hemifacial spasm induced by a small vestibular schwannoma that was totally resected. A 64-year-old man was admitted to our department with a 14-month history of symptomatic right-sided hemifacial spasm. During the process of microvascular decompression, no definite vessel was found to compress the facial nerve. By further exploration of regions other than root exit zone, a small vestibular schwannoma compressing the internal auditory canal portion of facial nerve from the ventral side was discovered. Resection of the tumor was then conducted. The symptoms of hemifacial spasm disappeared immediately after surgery.

CONCLUSIONS

We should be aware that magnetic resonance imaging is not always precise and perhaps misses some miniature lesions due to present image technique limitations. A small vestibular schwannoma might be the reason for HFS, although preoperative magnetic resonance tomography angiography showed possible vascular compression at the facial nerve root. More importantly, a full-length exploration of the facial nerve is in urgent need to find potential compression while performing microvascular decompression for HFS patients.

Tailored Approach and Multimodal Intraoperative Neuromonitoring in Cerebellopontine Angle Surgery

The cerebellopontine angle (CPA) is a highly complex anatomical compartment consisting of numerous nervous and vascular structures that present mutual and intricate spatial relationships. CPA surgery represents, therefore, a constant challenge for neurosurgeons. Over the years, neurosurgeons have developed and refined several solutions with the aim of maximizing the surgical treatment effects while minimizing the invasiveness and risks for the patient. In this paper, we present our integrated approach to CPA surgery, describing its advantages in treating pathologies in this anatomical district. Our approach incorporates the use of technology, such as neuronavigation, along with advanced and multimodal intraoperative neuromonitoring (IONM) techniques, with the final goal of making this surgery safe and effective.

Endovascular Treatment of Hemifacial Spasm Associated with a Tentorial DAVF Using Transarterial Onyx Embolization: A Case Report

Objective

We describe a patient treated with transarterial Onyx embolization for a tentorial dural arteriovenous fistula (DAVF) who presented with hemifacial spasm (HFS).

Case Presentation

A 56-year-old man suffered from right blepharospasm for 4 years, and the symptom gradually spread to the right side of his face with oculo-oral synkinesis. MRI of the brain revealed abnormal multiple flow voids at the surface of brainstem and cerebellar hemisphere. MRA (time of flight) and spoiled gradient recalled echo-revealed abnormal vessels at the posterior fossa indicated arteriovenous shunting. 3D-MRI fusion images showed that a dilated vein was in contact with the root exit zone (REZ) of the right facial nerve. The right carotid angiography displayed a complex tentorial DAVF on the right side. There were multiple feeding vessels drained to the tentorial sinus at the point where the inferior cerebellar vermian vein met, and severe venous congestion was noted. We diagnosed a tentorial DAVF and thought that this was responsible for the right HFS. We used neuroendovascular treatment for this lesion. After transarterial Onyx embolization, his right HFS diminished. MRI after treatment showed that the vein in contact with the REZ of the right facial nerve had shrank.

Conclusion

We experienced a rare case of HFS associated with a DAVF. Our case supports that transarterial Onyx embolization can treat HFS associated with a tentorial DAVF. It is the first description of successful treatment that could be confirmed through postoperative MRI.

Ingenuity using 3D-MRI fusion image in evaluation before and after microvascular decompression for hemifacial spasm

Background

Hemifacial spasm (HFS) is most often caused by blood vessels touching a facial nerve. In particular, responsible vessels compress the root exit zone (REZ) of the facial nerve. Although we recognize these causes of HFS, it is difficult to evaluate the findings of precise lesion in radiological imaging when vessels compress REZ. Hence, we tried to obtain precise images of pre- and postoperative neuroradiological findings of HFS by creating a fusion image of MR angiography and the REZ of facial nerve extracted by magnetic resonance imaging (MRI) diffusion tensor image (DTI).

Case Description

A 52-year-old woman had a 2-year history of HFS on the left side of her face. It was confirmed that the left vertebral artery and anterior inferior cerebellar artery were presented near the facial nerve on MRI. REZ of the facial nerve was visualized using DTI and fusion image was created with vascular components, making it possible to recognize the relationship between compression vessels and REZ of the facial nerve in detail. She underwent microvascular decompression and her HFS completely disappeared. We confirmed that the REZ of the facial nerve was decompressed by MRI imaging, in the same way as before surgery.

Conclusion

We describe that the REZ of facial nerve and compressive vessels was delineated in detail on MRI and this technique is useful for pre- and postoperative evaluation of HFS.

Deep Learning Based Real-Time Semantic Segmentation of Cerebral Vessels and Cranial Nerves in Microvascular Decompression Scenes

Automatic extraction of cerebral vessels and cranial nerves has important clinical value in the treatment of trigeminal neuralgia (TGN) and hemifacial spasm (HFS). However, because of the great similarity between different cerebral vessels and between different cranial nerves, it is challenging to segment cerebral vessels and cranial nerves in real time on the basis of true-color microvascular decompression (MVD) images. In this paper, we propose a lightweight, fast semantic segmentation Microvascular Decompression Network (MVDNet) for MVD scenarios which achieves a good trade-off between segmentation accuracy and speed. Specifically, we designed a Light Asymmetric Bottleneck (LAB) module in the encoder to encode context features. A Feature Fusion Module (FFM) was introduced into the decoder to effectively combine high-level semantic features and underlying spatial details. The proposed network has no pretrained model, fewer parameters, and a fast inference speed. Specifically, MVDNet achieved 76.59% mIoU on the MVD test set, has 0.72 M parameters, and has a 137 FPS speed using a single GTX 2080Ti card.

Association of intraocular pressure and postoperative nausea and vomiting after microvascular decompression - a prospective cohort study

BACKGROUND

Postoperative nausea and vomiting is common in patients receiving microvascular decompression. In the current study, we examined whether postoperative nausea and vomiting is associated with reduced intraocular pressure (IOP) after microvascular decompression, a measure that reflects intracranial pressure.

METHODS

This is a prospective cohort study. Adult patients scheduled for microvascular decompression surgery for hemifacial spasm between January 2020 and August 2020 were eligible. IOP was measured immediately before anesthesia induction and 30 min after patients regained complete consciousness using non-contact tonometry. IOP reduction was defined by at least 1 mmHg decrease vs. preoperative baseline. The primary outcome was vomiting on postoperative day 1.

RESULTS

A total of 103 subjects were enrolled. IOP was reduced in 56 (54.4%) subjects. A significantly greater proportion of patients with IOP reduction had vomiting on postoperative day 1 (51.8% (29/56) vs. 23.4% (11/47) in those without IOP reduction; p = 0.003). In the multivariate regression analysis, vomiting on postoperative day 1 was associated with female sex [odds ratio = 7.87, 95% CI: 2.35-26.32, p = 0.001] and IOP reduction [odds ratio = 2.93, 95% CI: 1.13-7.58, p = 0.027].

CONCLUSIONS

In patients undergoing microvascular decompression surgery, postoperative IOP reduction is associated with postoperative vomiting.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2000029083 . Registered 13 January 2020.

Factors Related to Hemifacial Spasm Recurrence in Patients Undergoing Microvascular Decompression—A Systematic Review and Meta-Analysis

There is a lack of knowledge about the factors associated with the recurrence of hemifacial spam (HFS) following an initially successful microvascular decompression (MVD) surgery. The aim of the present study was to systematically review the pertinent literature and carry out a meta-analysis of factors linked to HFS recurrence in patients undergoing initially successful MVD treatment. An online literature search was launched on the PubMed/Medline and Scopus databases. The following data were collected: sex, age at surgery, affected side, reported improvement after surgery, presence of post-operatory facial weakness, symptom duration, offender vessels, and data obtained from intraoperative neurophysiological monitoring. Upon full-text review, eight articles were included, studying 1105 patients, of which 64 (5.7%) reported recurrence after MVD surgery for hemifacial spasm. There was a statistically significant increased incidence of HFS recurrence in patients with the persistence of lateral spread response (LSR after surgery (OR 9.44 (95% CI 1.69–52.58) p 0.01), while those patients experiencing a shorter disease duration before going to surgery were significantly less prone to experiencing disease recurrence (OR 0.11 (95% CI 0.03–0.46) p 0.002). The remaining examined factors did not result as significantly associated with the risk of recurrence. The funnel plots were largely symmetrical for each variable studied. Taken together, the results of our meta-analysis seem to suggest that short-term symptom duration is a protective factor against HFS recurrence after MVD surgery, while LSR persistence is a negative prognostic factor. Well-designed randomized controlled clinical trials with a long follow-up are expected to further explore therapeutic alternatives for HFS recurrence.

Usefulness of intraoperative monitoring in microvascular decompression for hemifacial spasm: a systematic review and meta-analysis

OBJECTIVE

To review the diagnostic accuracy and possible added value of Brainstem Auditory Evoked Potentials (BAEP) monitoring and Lateral Spread Response (LSR) monitoring in microvascular decompression surgery for hemifacial spasms.

METHODS

For this systematic review we followed the PRISMA guidelines. We searched different databases and bibliographies of articles. We included studies on BAEP and LSR monitoring that reported data on hearing outcome or efficacy. Selected studies were assessed for bias using the MINORS tool.

RESULTS

64 articles were selected for qualitative synthesis, 42 met inclusion criteria for meta-analysis. The overall incidence of hearing loss was 3.4%. For BAEP monitoring AUC and pooled OR with 95% confidence interval were 0.911 (0.753-0.933) and 7.99 (3.85-16.60) respectively. Short-term data on LSR monitoring showed an overall spasm relief rate of 89% with pooled OR, sensitivity and specificity with a 95% confidence interval of 8.80 (4.82-16.08), 0.911 (0.863-0.943) and 0.451 (0.342-0.564) respectively. Long-term data on LSR monitoring showed an overall spasm relief rate of 95% with pooled OR, sensitivity and specificity with a 95% confidence interval of 4.06 (2.15-7.64), 0.871 (0.817-0.911) and 0.39 (0.294-0.495) respectively.

CONCLUSION

The alarm criteria, a wave V latency prolongation of 1ms or a wave V amplitude decrement of 50%, proposed by the 'American Clinical Neurophysiology Society' are a sensitive predictor for postoperative hearing loss. Other BAEP wave changes, for example, complete loss of wave V, are more specific but correspond to irreversible damage and are therefore not useful as warning criteria. LSR monitoring has high diagnostic accuracy at short-term follow-up. At long-term follow-up, diagnostic accuracy decreases because most patients get spasm relief regardless of their LSR status. LSR persistence after surgery has a good long-term outcome, as long as an extensive exploration of the facial nerve has been performed.

[Higher efficacy of botulinum toxin therapy for hemifacial spasm recurrence after vascular decompression. Case report and literature review]

Hemifacial spasm (HFS) is an involuntary synchronous tonic and/or clonic contraction of mimic muscles following ipsilateral facial nerve dysfunction. The last one is a result of neurovascular conflict between the facial nerve and vessel. Currently, vascular decompression is a pathogenetic treatment modality for primary HFS. Various authors describe postoperative recurrence of HFS, and botulinum toxin therapy remains the only option for these patients. We aimed to describe the efficacy of botulinum toxin therapy in patients with HFS recurrence after surgical vascular decompression. The article presents a female patient with a long-term history of HFS and botulinum toxin therapy (with different formulations). Efficacy of therapy gradually decreased (progressive reduction of intervals between injections). MRI revealed a close relationship between posterior inferior cerebellar artery and roots of acoustic-facial nerves near the brainstem. The patient underwent vascular decompression of the left facial nerve root under intraoperative monitoring with positive postoperative outcome. However, HFS symptoms recurred in 3 days after surgery. Botulinum toxin type A (BTA) injections were resumed with significant positive effect that can be explained by reduction of one of the factors involved into HFS. Thus, patients with HFS recurrence after vascular decompression may benefit from BTA therapy.

Botulinum Toxin for the Treatment of Hemifacial Spasm: An Update on Clinical Studies

Hemifacial spasm (HFS) is a movement disorder characterized by involuntary contractions of the facial muscles innervated by the seventh cranial nerve. Generally, it is associated with a poor quality of life due to social embarrassment and can lead to functional blindness. Moreover, it is a chronic condition, and spontaneous recovery is rare. Intramuscular injections of Botulinum Toxin (BoNT) are routinely used as HFS treatment.

METHODS

We reviewed published articles between 1991 and 2021 regarding the effectiveness and safety of BoNT in HFS as well as any reported differences among BoNT formulations.

RESULTS

The efficacy of BoNT for HFS treatment ranged from 73% to 98.4%. The mean duration of the effect was around 12 weeks. Effectiveness did not decrease over time. Adverse effects were usually mild and transient. The efficacy and tolerability of the different preparations appeared to be similar. Among the studies, dosage, injected muscles, intervals of treatment, and rating scales were variable, thus leading to challenges in comparing the results.

CONCLUSIONS

BoNT was the treatment of choice for HFS due to its efficacy and safety profile. Further studies are needed to investigate the factors that influence the outcome, including the optimal timing of treatment, injection techniques, dosage, and the best selection criteria for formulations.

Awake CT-guided percutaneous stylomastoid foramen puncture and radiofrequency ablation of facial nerve for treatment of hemifacial spasm

OBJECTIVE

Hemifacial spasm (HFS) is a debilitating neuromuscular disorder with limited treatment options. The current study describes a novel minimally invasive procedure that provided effective and sustained relief for patients with HFS. The authors provide a detailed description of the awake CT-guided percutaneous radiofrequency ablation (RFA) of the facial nerve for treatment of HFS, and they examine its clinical efficacy. This is the first time in the literature that this procedure has been applied and systematically analyzed for HFS.

METHODS

Patients with a history of HFS were recruited between August 2018 and April 2020. Those with a history of cerebellopontine lesions, coagulopathy, ongoing pregnancy, cardiac pacemaker or defibrillator implants, or who declined the procedure were excluded from the study. Fifty-three patients who met the study criteria were included and underwent awake CT-guided RFA. Under minimal sedation, a radiofrequency (RF) needle was used to reach the stylomastoid foramen on the affected side under CT guidance, and the facial nerve was localized using a low-frequency stimulation current. Patients were instructed to engage facial muscles as a proxy for motor monitoring during RFA. Ablation stopped when the patients' hemifacial contracture resolved. Patients were kept for inpatient monitoring for 24 hours postoperatively and were followed up monthly to monitor resolution of HFS and complications for up to 19 months.

RESULTS

The average duration of the procedure was 32-34 minutes. Postoperatively, 91% of the patients (48/53) had complete resolution of HFS, whereas the remaining individuals had partial resolution. A total of 48 patients reported mild to moderate facial paralysis immediately post-RFA, but most resolved within 1 month. No other significant complication was observed during the study period. By the end of the study period, 5 patients had recurrence of mild HFS symptoms, whereas only 2 patients reported dissatisfaction with the treatment results.

CONCLUSIONS

The authors report for the first time that awake CT-guided RFA of the facial nerve at the stylomastoid foramen is a minimally invasive procedure and can be an effective treatment option for HFS.

Endoscopic Microvascular Decompression for Hemifacial Spasm: A Technical Case Report Demonstrating the Benefits of the Angled Endoscope and Intraoperative Neuromonitoring

A 57-year-old female with eight years of hemifacial spasm (HFS) underwent endoscopic microvascular decompression (MVD) of the facial nerve. Baseline stimulation of the zygomatic branch of the facial nerve activated at 1.2 mA. Lateral spread response (LSR) to the buccal and mandibular branches was observed at 2.2 mA. A straight endoscope was used to enter the cerebellopontine angle, allowing for visualization of the vestibulocochlear and facial nerve. Neurovascular compression was not clearly identified. A 30-degree endoscope was directed medially/inferiorly and compression at the root entry zone was identified and decompressed. Subsequent LSR to the buccal/mandibular branches was seen at 3.2 mA/3.6 mA, respectively. Additional vascular compression was suspected given persistent LSR. The 30-degree endoscope was directed laterally. Compression was seen at the porus acustics and decompressed. Subsequent LSR to the buccal/mandibular branches was not observed until 9.8 mA, indicating good decompression. The patient tolerated the procedure well with complete resolution of her symptoms and remains spasm-free as of three months post-procedure without a hearing deficit. The 30-degree endoscope enabled visualization of pathology that was not easily seen at 0-degree. Additionally, LSR indicated persistent nerve compression following root entry zone decompression. Subsequent distal decompression resulted in greater LSR reduction. This case report suggests that MVD for HFS may yield better results with both proximal and distal decompression of the seventh nerve, and this type of decompression can benefit from endoscopic visualization.

Imaging predictors of successful surgical treatment of hemifacial spasm

Identify preoperative imaging findings in hemifacial spasm patients that predict the post-surgical success following microvascular decompression. This is a retrospective study of patients who were diagnosed with hemifacial spasm, had a dedicated cranial nerve MRI, and underwent microvascular decompression for hemifacial spasm. Bilateral facial nerves were interrogated for neurovascular compression. If neurovascular compression was identified, we recorded whether the offending vessel was an artery, a vein or both. The location of the neurovascular compression (proximal nerve versus distal nerve) was noted. The severity of the neurovascular compression was categorized as contact versus deformity of the nerve. Patients were contacted to determine their post-operative spasm status. The relationships between imaging findings and post-surgical outcome were assessed by Chi-square tests, and odds ratios were calculated to quantify the degree of association. The study included 212 patients. Upon follow up, 192 patients were spasm free (90.57%). Imaging findings on the symptomatic side were as follows: arterial neurovascular compression was seen in 207 patients (97.64%), venous only neurovascular compression in two patients (0.94%), and no neurovascular compression in three patients (1.42%). Arterial neurovascular compression along the proximal, susceptible segment of the nerve was observed in 202 patients (95.28%); deformity was observed more commonly than contact alone. Arterial neurovascular compression along the distal segment only of the nerve was observed in five patients (2.36%). In patients with arterial neurovascular compression of the proximal and distal portions of the nerve, 93.07% and 60.0% of patients were spasm-free respectively. If venous neurovascular compression only was observed on imaging, 0% of patients were spasm-free. Patients with arterial neurovascular compression of the susceptible segment are much more likely to be spasm free than patients without this imaging finding, [odds ratio 20.14 (CI 5.08, 79.81), P-value <0.0001]. When comparing the two groups of arterial neurovascular compression (deformity versus contact), no statistically significant difference in outcomes was observed. In patients with hemifacial spasm undergoing microvascular decompression, imaging findings do predict surgical outcome. Patients with arterial neurovascular compression of the proximal, susceptible portion of the nerve are much more likely to be spasm free after surgery than those without this imaging finding. The imaging findings inform the risk benefit analysis and discussion with patients before they undergo microvascular decompression for hemifacial spasm.

Efficacy of Second Operation for Hemifacial Spasm Within 1 Week After Ineffective Microvascular Decompression

OBJECTIVE

To evaluate the efficacy of the second operation within 1 week after ineffective microvascular decompression (MVD) for patients with primary hemifacial spasm (HFS), and to find out the causes of failure.

METHODS

The surgery records and postoperative follow-ups of 52 primary HFS patients who had poor relief of spasm after their first MVDs were investigated. Patients were divided into 2 groups. Group A included 46 patients (16 males and 30 females) that went through the second operation within 1 week after the failure of the first MVD. Group B included 6 patients (3 males and 3 females) which did not take the reoperation. The level of spasm of each patient was then re-evaluated 1 year after the first surgery.

RESULTS

Among 52 patients who had poor relief after the first MVD between April 2016 and October 2019, 46 patients underwent a second MVD within 1 week while 6 patients refused to take the reoperation. Their mean duration of HFS was 102.4 ± 57.9 months. During reoperations for patients in group A, we discovered additional sites of neurovascular compression in 11 cases (23.91%). Forty-five patients (97.82%) in group A achieved complete relief 1 year after the second surgery while there was 1 recurrent case. Four patients (66.67%) in group B achieved delayed relief 1 year after the first surgery, while the other 2 patients were still suffering facial spasm in the 1-year follow-up. Group A demonstrated higher relief rate compared to group B in the 1 year follow up (P = 0.032). Although no severe complications occurred on patients in both group, 4 of them suffered grade II facial palsy, and another 3 patients had developed mild temporary hearing loss on the operation side.

CONCLUSION

The second operation within 1 week after an ineffective MVD is safe and effective. Full revealing of root exit zone and making sure no neurovascular compression missed with abnormal muscle response monitoring are the keys to a successful MVD.

The Efficacy and Safety of <2 cm Micro-Keyhole Microvascular Decompression for Hemifacial Spasm

Objective: Microvascular decompression (MVD) surgery has been accepted as a minimally invasive surgical modality for the treatment of hemifacial spasm (HFS). However, the size of the bone window does not match the concept of minimally invasive. This study is aimed at evaluating the efficacy and safety of <2 cm micro-keyhole MVD.

Methods: A total of 148 patients with HFS diagnosed in the First Affiliated Hospital of Chongqing Medical University from January 1, 2019, to July 1, 2020, who underwent MVD in the neurosurgery department of the hospital were collected. Surgery was performed by a retrosigmoid keyhole approach with the bone hole diameter <2 cm, which was named micro-keyhole MVD. The efficacy and safety of the micro-keyhole MVD were evaluated by statistical analysis of the efficacy of the micro-keyhole MVD and the incidence of postoperative complications.

Results: The effect of micro-keyhole MVD was satisfying (cure or partial remission) in 97.2% (n = 144). The failure and recurrence rates were 2.7% (n = 4) and 0.6% (n = 1), respectively. Among them, immediate facial palsy, delayed facial palsy, hearing loss, and cerebrospinal fluid (CSF) leakage were found in 0.6% (n = 1), 8.1% (n = 12), 4.7% (n = 7), and 1.3% (n = 2). Only one patient developed cerebellar infarction, which was complicated by “moyamoya disease.” The micro-keyhole MVD in the treatment of HFS can achieve a high remission rate and reduce the incidence of surgical complications.

Conclusion: Micro-keyhole MVD is a safe and effective minimally invasive treatment for HFS. This technique does not increase the incidence of cranial nerve injury. Meanwhile, it reduces the incidence of CSF leakage and hearing loss (HL).

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.

Role of neuroimaging in cases of primary and secondary hemifacial spasm

Purpose:

The objective of this study was to analyze the role of neuroimaging and documenting various intracranial pathologies in primary and secondary hemifacial spasm.

Methods:

This retrospective study included patients with HFS who had undergone neuroimaging. The demographic profile, onset, progression, neuroimaging findings, and types of HFS were documented and analyzed.

Results:

A total of 202 patients (male = 110, female = 92) were included. The mean age of the study population was 51.81 ± 11.76 years. The right side was involved in 104 patients, the left side was involved in 97 patients and bilateral involvement was observed in one patient. Primary HFS: secondary HFS was 9.6:1. The mean age of onset of the spasms in the primary HFS group was 49.26 ± 8.35 years and in secondary HFS was 43.13 ± 12.12 years respectively. The anterior inferior cerebellar artery was the major vessel causing neurovascular conflict in primary HFS (n = 55). Facial nerve palsy was the most common cause (n = 13) of secondary HFS followed by cerebellopontine angle (CPA) tumors.

Conclusion:

The hemifacial spasm occurs mostly in the fifth decade of life. Primary HFS is more prevalent than secondary HFS. Clinical distinction between them is difficult. Neuroimaging is essential to detect the conflicting vasculature in cases of primary HFS and pathologies like CPA tumor, cyst, and aneurysms in cases of secondary HFS.

Prospective, Multicenter Clinical Study of Microvascular Decompression for Hemifacial Spasm

BACKGROUND

Microvascular decompression (MVD) is the most effective procedure for hemifacial spasm (HFS). MVD results from nonspecialized or low-volume institutes are not always reliable. Most studies on MVD for HFS are retrospective and single centered; to the best of our knowledge, no prospective, multicenter studies exist.

OBJECTIVE

To evaluate short- and long-term outcomes and complications in patients who underwent MVD for HFS in specialized Japanese institutions, in this multicenter, prospective, cohort study.

METHODS

Included patients had undergone MVD for HFS in study centers between April 2012 and March 2015. Patients' postoperative grade of involuntary movements and complications were recorded postoperatively at 7 d (short-term) and at 1 (mid-term) and 3 (long-term) yr.

RESULTS

A total of 486 patients (150 men, 336 women; mean age 53.9 yr with 181 patients over 60 yr) were enrolled during the study period. Neuromonitoring was used in 96.3% of the cases. The complete cure rate of symptom relief, mortality rate, and complication rate at short-term follow-up were 70.6%, 0%, and 15%, respectively. The long-term follow-up was completed by 463 patients (95.3%); the complete cure rate of symptom relief and complication rate were 87.1% and 3.0%, respectively.

CONCLUSION

Our study revealed that under expert guidance and intraoperative neuromonitoring, the long-term curative effect rate of MVD for HFS is high, while complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with HFS, including elderly patients.

Quality of life after hemifacial spasm surgery: French versions of the HFS-8 and HFS-30 questionnaires

OBJECTIVES

The aim of the present study was to assess quality of life before and after surgery for hemifacial spasm, in order to validate two specific quality of life scales translated in French. Surgical results and complications were reported.

MATERIAL AND METHODS

Twenty-three patients with hemifacial spasm treated by microvascular decompression were retrospectively included. The HFS-8 and HFS-30 quality of life scales were translated from English into French using a forward-backward method and implemented on patients at least one year after surgery.

RESULTS

Median HFS-8 and HFS-30 values were respectively 16±12.5 (range: 8-20.5) and 38±38.5 (range: 23-61.5) before surgery and 0.5±4.5 (range: 0-4.5) and 5±17.5 (range: 1-18.5) after surgery, showing significant improvement in quality of life (P<0.001). The internal consistency of both scales was excellent (Cronbach's alpha>0.9), and they were significantly correlated (Pearson coefficient=0.95; 95% CI [0.91; 0.98]; P<0.0001). Success rates were 83% and 91%, respectively, after primary and revision surgeries. Complications were transient with minor consequences in 80% of cases, but could impact quality of life when lasting.

CONCLUSIONS

These results support the validity of the French versions of HFS-8 and HFS-30. Microvascular decompression is a safe and effective treatment for hemifacial spasm, and these scales are reliable tools to assess postoperative quality of life.

Challenging Microvascular Decompression Surgery for Hemifacial Spasm

OBJECTIVE

Microvascular decompression (MVD) is the most effective treatment for hemifacial spasm (HFS). However, surgical difficulties due to complex anatomy or revision surgery can endanger the functional integrity of the brainstem. We describe surgically challenging cases and provide operative guidance that may be helpful for neurosurgeons who perform MVDs.

METHODS

Of 3028 patients with HFS who underwent MVDs consecutively by a single neurosurgeon, complex or unusual cases associated with surgical difficulty were selected. Medical charts and images were reviewed, with the primary focus being intraoperative findings, operative techniques, and clinical outcomes. All MVDs were performed using the interposition method.

RESULTS

Surgically difficult cases were categorized into six types: tandem, perforator, atypical location, encircling, revision, and penetrating types. During the follow-up period (11.5-42.7 months; median 24.9 months), the spasm-free rate was 88.4%. Intraoperative changes in brainstem auditory evoked potentials were observed in 31.5% of patients. Immediate postoperative facial palsy and deafness were observed in 6.0% and 1.5% of patients, respectively. Revision surgery showed the highest surgical morbidity among the unusual HFS types. Detailed illustrations and descriptions of MVD in patients with surgically challenging HFS are provided.

CONCLUSIONS

Complex or unusual HFS types carry higher surgical risks in MVD. Neurosurgeons performing MVDs need to be prepared to manage complex HFS cases in order to achieve favorable clinical outcomes.

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.

[Hemifacial spasm. Etiology and management]

INTRODUCTION

Hemifacial spasm (HFS) is an involuntary contracture of the facial muscles innervated by the ipsilateral facial nerve. We studied the etiology of these HFS.

MATERIALS AND METHODS

This retrospective study included 233 patients with HFS who came to the ophthalmologist for quarterly botulinum neurotoxin A injection. Of these, we analyzed the 198 patients for whom MRI scans were performed. We recorded patient clinical data and clarified the etiology of their HFS.

RESULTS

The 198 patients (62.6% women) had a mean age of 55.7±14years. An etiology was found in 52.5% of cases. In 34.5% of HFS, MRI revealed vascular compression where the facial nerve emerged from the brainstem. We specify the arteries involved. Brain tumors accounted for 1.5% of cases. MRI was normal in 64.5% of cases. In these secondary cases of HFS, we found 8.5% peripheral facial palsy, 4% post-traumatic HFS and 4% secondary to an eye injury. Stress was found in 17% of patients.

DISCUSSION AND CONCLUSION

This study illustrates the need for MRI with attention to the posterior fossa in the work-up of HFS in order to identify primary HFS associated with vascular compression of the facial nerve and to rule out a rare but serious posterior fossa tumor. The treatment of HFS is based on quarterly injections of botulinum neurotoxin/A (NTBo/A), the three brands of which have market approval. The injection pattern and frequency is customized according to the results. In cases of insufficient response to injections of NTBo/A, neurosurgical microvascular decompression may be considered for cases of primary HFS.

Image Fusion in Neurovascular Compression Syndrome Related to Hemifacial Spasm

Neurovascular compression syndromes have well characterized clinical symptoms, but precise identification of the pathologic contact between the nerves and vessels can be challenging at neuroimaging. Considering that neurovascular contacts are frequent imaging findings in asymptomatic patients, correct visualization of pathological contact is crucial for the diagnosis and surgical planning. We have used magnetic resonance imaging fusion by overlaying color-coded T1-weighted postcontrast onto high-resolution T2-weighted images to better delineate imaging findings by enhancing vascular structures.