Clinico-radiologic correlation in unilateral and bilateral hemifacial spasm

How to face the hemifacial spasm: challenges and misconceptions

Hemifacial spasm (HFS) is characterised by intermittent, brief or sustained, repetitive contractions of the muscles innervated by one facial nerve. It is one of the most frequent movement disorders affecting the face. However common and allegedly straightforward to diagnose, it might reveal as a challenge for clinicians in various situations. Indeed, it often needs prior exclusion of many other movement disorders affecting the face, with frequent phenomenological overlaps with blepharospasm, post-facial palsy, facial motor tics, etc. The clinical diagnosis shall be supported by modern brain imaging techniques, and sometimes electromyography, as some particular aetiologies may require specific treatment. Primary forms are associated with vascular compression of the ipsilateral seventh cranial nerve, whereas secondary forms can be caused by any injury occurring on the facial nerve course. This article proposes a global and organised approach to the diagnosis, and the ensuing therapeutic options, as many practitioners still use some inefficient medications when they encounter a case of facial spasm.

Higher betweenness and degree centrality in the frontal and cerebellum cortex of Meige's syndrome patients than hemifacial spasm patients

Meige's syndrome and hemifacial spasm (HFS) are two different forms of dystonic movement disorder, but their difference in terms of resting state functional connectivity (rsFC) remains unclear. The present study applied resting state fMRI on the patients and quantified their functional connectivity with graph theoretical measures, including the degree centrality and the betweenness centrality. Fifteen Meige's syndrome patients and 19 HFS patients matched in age and gender were recruited and their MRI data were collected. To analyze the rsFC, we adopted the Anatomical Automatic Labeling (AAL) template, a brain atlas system including 90 regions of interest (ROIs) covering all the brain regions of cerebral cortex. For each participant, the time-course of each ROI was extracted, and the corresponding degree centrality and betweenness centrality of each ROI were computed. These measures were then compared between the Meige's syndrome patients and the HFS patients. Meige's syndrome patients showed higher betweenness centrality and degree centrality of bilateral superior medial frontal cortex, the left cerebellum cortex, etc. than the HFS patients. Our results suggest that the rsFC pattern in Meige's syndrome patients might become more centralized toward the prefrontal and vestibular cerebellar systems, indicating less flexibility in their functional connections. These results preliminarily revealed the characteristic abnormality in the functional connection of Meige's patients and may help to explore better treatment.

Reoperation for residual or recurrent hemifacial spasm after microvascular decompression

PURPOSE

Microvascular decompression (MVD) surgery is the only potential curative method for hemifacial spasm (HFS). Little attention is paid to those recurrent/residual HFS cases. We want to study the potential etiology of those recurrent/residual HFS cases and evaluate the value of reoperation.

METHODS

We retrospectively reviewed reoperation hemifacial spasm patients in our hospital. Intraoperative videos or images were carefully reviewed, and the etiology of recurrent/residual HFS is roughly divided into three categories. Intraoperative findings, surgical outcomes, and complications were carefully studied to assess the value of reoperation for recurrent/residual HFS patients.

RESULTS

A total of 28 cases were included in our case series. Twenty-three of them are recurrent HFS cases, and 5 of them are residual HFS cases. The mean follow-up duration is 24.96 months. There are seventeen patients with missed culprit vessels or insufficient decompression of root exit zone (REZ), eight patients with Teflon adhesion, and three patients with improper application of decompression materials in our case series. The final reoperation outcome with 17 excellent, seven good, and four fair, respectively. Eight (28.57%) of them experienced long-term complications after reoperation.

CONCLUSION

Re-operation for recurrent/residual HFS is an effective therapy and can achieve a higher cure rate. However, the complication rate is higher compared to the first MVD surgery. Accurately identifying REZ and proper decompression strategies to deal with the culprit vessels are very important for surgical success.

TRIAL REGISTRATION NUMBER

UIN: researchregistry7603. Date of registration: Jan. 31st, 2022 "retrospectively registered".

Efficacy of fire needle on patients of facial spasm: A protocol for systematic review and meta analysis

BACKGROUND

Facial spasm causes a lot of troubles to patients daily life and seriously affects their mental and physical health. Relevant studies have shown that fire needle therapy has certain benefits for facial spasm, is an integral part of acupuncture therapy. However, there is no unanimous conclusion. The main purpose of our study is to measure whether fire needle therapy is effective for facial spasm.

METHODS

The following electronic databases will be searched for the collection of fire-needle related randomized controlled trials (RCTS) for facial spasm, including 4 English databases (Web of Science, the Cochrane Library, EMBASE, Pubmed) and 3 Chinese databases (Chinese National Knowledge Infrastructure [CNKI], Wanfang data, Chinese VIP Information). The cure rate and total effective rate are the main outcomes, while the intensity, frequency, recurrence rate and adverse events are the secondary outcomes. We will use Endnote software X9 for study selection, Review Manager software 5.4 and STATA 13.0 software for analysis and synthesis.

RESULTS

We will evaluate the efficacy of fire needles in the treatment of facial spasm in combination with current studies.

CONCLUSION

The conclusion of this study will provide evidence for the efficacy of fire needle in the treatment of facial spasm.

TRIAL REGISTRATION NUMBER

INPLASY202080036.

Two-dimensional structure analysis of hemifacial spasms and surgical outcomes of microvascular decompression

BACKGROUND

Although studies have indicated that the small posterior fossa plays a role in hemifacial spasm (HFS), few studies have denoted the correlations between local measurements of the cerebellopontine angle and the incidence of HFS and surgical outcomes.

METHODS

We retrospectively analyzed the demographic and clinical data of HSF patients who underwent microvascular decompression at our institution. Healthy controls were recruited. The divergent prognosis of HFS was defined as an ordinal variable. A multivariable ordinal regression model was generated to estimate the relationship between the variables and outcomes of HFS.

RESULTS

Between 2013 and 2018, 180 patients who were enrolled in our study met the inclusion criteria. Compared with the control group (n = 94), HFS patients had a smaller internal acousticmeatus-brainstem distance (P < 0.001) on the unaffected side and a larger facial nerve-brainstem angle (P < 0.001). The regression analysis demonstrated that subgroups with more severe facial nerve compression (mild vs severe, OR = 0.269, P = 0.018; moderate vs severe, OR = 0.215, P < 0.001) and a thinner brainstem (OR = 2.368, P = 0.014) were more likely to experience better short-term outcomes, while subgroups with a thinner brainstem (OR = 5.583, P = 0.007) were more likely to experience better long-term outcomes.

DISCUSSION

Structural changes occurring in patients are risk factors for HFS. The patient's local neurovascular structure and brainstem volume are factors that significantly influence short-term and long-term surgical outcomes.

Acupuncture therapy for patients with hemifacial spasm: A protocol of systematic review and meta-analysis

BACKGROUND

Hemifacial spasm (HFS) brings a lot of trouble to patients' daily life, having a severe influence on the psychological and physical wellbeing of patients. Relevant researches suggested that acupuncture therapy has potential benefits for HFS. However, there is no consistent conclusion. The purpose of our study is to assess whether acupuncture therapy is effective and safe for HFS.

METHODS

To collect relevant randomized controlled trials (RCTs), the following electronic databases will be searched: Web of Science, the Cochrane Library, EMBASE, MEDLINE, ISI Web of Knowledge, PsycINFO, Allied and Alternative Medieine, Chinese National Knowledge Infrastructure, Wanfang data, and Chinese Scientific Journals Database. We will take the cure rate and the total effective rate as the primary outcomes, and change in intensity after treatment, change in frequency after treatment, the recurrence rate, and adverse events as secondary outcomes. Endnote software 9.1 will be used for study selection, Review Manager software 5.3, and STATA 13.0 software will be used for analysis and synthesis.

RESULTS

Current relevant studies will be synthesized to assess whether acupuncture therapy is effective and safe for HFS.

CONCLUSION

Our research will provide evidence of acupuncture therapy for HFS.

REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) CRD42019142473.

Synchronous bilateral hemifacial spasm: case-report and literature review

Bilateral hemifacial spasm (biHFS) is an infrequent cranial nerve disorder that causes patients to suffer from severe psychological stress, and there are no reported cases of synchronous biHFS. In this study, a 46-year-old right-handed woman was diagnosed with a synchronous biHFS. After one unilateral microvascular decompression (MVD) surgery, the left facial twitching movements relieved immediately, and the right side twitching movements self-relieved the next day. Although there was a delayed hemorrhage, the patient achieved a satisfactory outcome defined as cessation of the twitching movements without recurrence. Based on the present case and related literature, we speculate that anatomical connections between bilateral facial nuclei and hyperactivity of facial nuclei play important roles in the biHFS, and they may, at least in some cases, be the decisive factors regarding the origin, development, and relief of the consequent contralateral spasm.

Treatment of Blepharospasm/Hemifacial Spasm

OPINION STATEMENT

The treatment of both hemifacial spasm (HFS) and blepharospasm (BEB) requires making the appropriate clinical diagnosis. Advance imaging and electrophysiologic studies are useful; however, one's clinical suspicion is paramount. The purpose of this review is to summarize current and emerging therapies for both entities. Botulinum toxin (BTX) remains the first-line therapy to treat both conditions. If chemodenervation has failed, surgery may be considered. Due to the risks associated with surgery, the benefits of this option must be carefully weighed. Better surgical outcomes are possible when procedures are performed at tertiary centers with experienced surgeons and advanced imaging techniques. Microvascular decompression is an efficacious method to treat HFS, and myectomy is an option for medication-refractory BEB; the risks of the latter may outweigh any meaningful clinical benefits. Oral agents only provide short-term relief and can cause several unwanted effects; they are reserved for patients who cannot receive BTX and/or surgery. Transcranial magnetic stimulation has gained some traction in the treatment of BEB and may provide safer non-invasive options for refractory patients in the future.

Tenth case of bilateral hemifacial spasm treated by microvascular decompression: Review of the pathophysiology

BACKGROUND

Bilateral hemifacial spasm (BHFS) is a rare neurological syndrome whose diagnosis depends on excluding other facial dyskinesias. We present a case of BHFS along with a literature review.

METHODS

A 64-year-old white, hypertense male reported involuntary left hemiface contractions in 2001 (aged 50). In 2007, right hemifacial symptoms appeared, without spasm remission during sleep. Botulinum toxin type A application produced partial temporary improvement. Left microvascular decompression (MVD) was performed in August 2013, followed by right MVD in May 2014, with excellent results. Follow-up in March 2016 showed complete cessation of spasms without medication.

RESULTS

The literature confirms nine BHFS cases bilaterally treated by MVD, a definitive surgical option with minimal complications. Regarding HFS pathophysiology, ectopic firing and ephaptic transmissions originate in the root exit zone (REZ) of the facial nerve, due to neurovascular compression (NVC), orthodromically stimulate facial muscles and antidromically stimulate the facial nerve nucleus; this hyperexcitation continuously stimulates the facial muscles. These activated muscles can trigger somatosensory afferent skin nerve impulses and neuromuscular spindles from the trigeminal nerve, which, after transiting the Gasser ganglion and trigeminal nucleus, reach the somatosensory medial posterior ventral nucleus of the contralateral thalamus as well as the somatosensory cortical area of the face. Once activated, this area can stimulate the motor and supplementary motor areas (extrapyramidal and basal ganglia system), activating the motoneurons of the facial nerve nucleus and peripherally stimulating the facial muscles.

CONCLUSIONS

We believe that bilateral MVD is the best approach in cases of BHFS.

Prevalence of Bruxism in Hemifacial-Spasm Patients

PURPOSE

A previous study reported an increased prevalence of bruxism (25%) in patients with cranio-cervical dystonia (CCD) compared to normal controls (13%). CCD can affect the muscles of the head and neck. Besides the CCD affecting these muscles, hemifacial spasm (HFS) is a form of peripheral myoclonus due to a neurovascular conflict affecting the muscles of the face. The fact that they affect the same muscle regions could lead to other links in clinical manifestations such as bruxism, which is more common in patients with CCD than in the normal population. The aim was to study the prevalence of bruxism in patients with HFS.

MATERIALS AND METHODS

Patients with HFS were enrolled in the department of clinical neurophysiology (Bordeaux University Hospital) over a 6-month period. They were paired regarding age, the absence of neurological pathology or neuroleptics intake. To be included in the study, patients needed to have had unilateral involuntary facial muscle contractions affecting one hemiface. A hetero-questionnaire and a clinicial study were performed. The diagnostic criteria of bruxism included parafunction items such as grinding and clenching and at least one of the following clinical signs: abnormal tooth wear, temporomandibular joint (TMJ) pain, TMJ clicking, muscle hypertonia (masseter or temporal muscles). Additional epidemiological data were collected including age, sex, disease duration, stress, and sleep disorders. Stress symptoms inventory included symptoms like depression, strong heartbeat, dry mouth, anger, inability to concentrate, weakness, fatigability, insomnia, headache, and excessive sweating. The sleep disorder diagnosis included at least two of the symptoms described in the ICSD-3. All these criteria were recorded as either present (scored "1") or absent (scored "0").

RESULTS

The prevalence of bruxism in the two groups (normal and HFS) was not significantly different (p = 0.37). The rate was not significantly different between sleep and awake bruxism (p = 0.15) in both groups. Stress influenced the occurrence of bruxism in these two groups (p < 0.001).

CONCLUSION

The results of this study indicated that clenching behaviors were higher in the HFS group, and that factors such as stress affected this group. The prevalence of bruxism was not higher in this population than in the normal control.

Management of Bilateral Hemifacial Spasm with Microvascular Decompression

BACKGROUND

Bilateral hemifacial spasm (HFS) is very rare. The literature contains only 32 clinical reports. Although microvascular decompression (MVD) is widely accepted as effective therapy for HFS, the etiology and surgical treatment of bilateral HFS are seldom addressed. We report our experience with MVD for patients with bilateral HFS.

METHODS

This retrospective report included 10 patients with bilateral HFS. All patients underwent MVD 1 or 2 times and were followed for 5-92 months. The clinical data were retrospectively analyzed. The etiology and treatment strategies were discussed.

RESULTS

Spasm stopped completely on the operative side in all 10 patients. Symptoms on the other side also resolved in 3 patients, improved in 1 patient, and did not improve at all in 6 patients. Of the 6 patients with no improvement, 5 underwent another MVD on the contralateral side within 1 year and experienced relief of symptoms, and 1 patient refused the surgery. The neurovascular conflict was found in all the operations. During the follow-up period, no complications of hearing loss or facial palsy and no recurrence were observed.

CONCLUSIONS

Vascular compression was the cause of bilateral HFS in our patients, and MVD relieved the symptoms. Thus, we recommend MVD for patients with bilateral HFS. A crowded cerebellopontine angle space and easy attrition of the neurovascular interfaces may play important roles in the occurrence of bilateral HFS. For some patients, 1 MVD can resolve bilateral symptoms.

Hemifacial spasm and neurovascular compression

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

Misdiagnosis of hemifacial spasm is a frequent event in the primary care setting

Primary hemifacial spasm (HFS) is characterized by irregular and involuntary contraction of the muscles innervated by the ipsilateral facial nerve. Treatment controls symptoms and improves quality of life (QoL). Objective : Evaluate the initial diagnosis and treatment of HFS prior to referral to a tertiary center. Method : We interviewed through a standard questionnaire 66 patients currently followed in our center. Results : Mean age: 64.19±11.6 years, mean age of symptoms onset: 51.9±12.5 years, male/female ratio of 1:3. None of the patients had a correct diagnosis in their primary care evaluation. Medication was prescribed to 56.8%. Mean time from symptom onset to botulinum toxin treatment: 4.34 ±7.1 years, with a 95% satisfaction. Thirty percent presented social embarrassment due to HFS. Conclusion : Despite its relatively straightforward diagnosis, all patients had an incorrect diagnosis and treatment on their first evaluation. HFS brings social impairment and the delay in adequate treatment negatively impacts QoL.

Complementary therapies in hemifacial spasm and comparison with other movement disorders

OBJECTIVES

We determined the prevalence, range and factors influencing the use of complementary therapy among hemifacial spasm patients and compared the patterns of use of complementary therapies across different movement disorders in a systematic pooled analysis of published literature.

METHODS

A structured questionnaire was administered to 96 hemifacial spasm patients evaluating frequency of complementary therapy use, and factors influencing patients' decision to seek these therapies. We also performed a PubMed search of epidemiology studies on use of complementary therapies in movement disorders.

RESULTS

Fifty-one per cent of patients had tried complementary therapies, of which 47% reported some perceived benefit and 4.1% informed their doctor. Acupuncture (71.4%) and facial massage (17.6%) were most commonly used. Complementary therapy use was associated with greater HFS severity. The mean cost of treatment was about $78 per month. We identified eight articles on use of complementary therapies in movement disorders; Parkinson's disease (5), Tourette syndrome (2) and dystonia (1). Twenty-five to 88% of patient had tried complementary therapies, of which 32-70% reported some benefit. Trials of acupuncture (2-63%) and massage (7-38%) were reported across the spectrum of movement disorders studied. Mean cost of complementary therapies varied from 43 to 102 USD per month.

CONCLUSION

Complementary therapies are used by over 50% of HFS patients, and the use is correlated with severity of disease. Despite differences in race, culture and population demographics, acupuncture and massage are used by patients across the spectrum of movement disorders.

Headache in hemifacial spasm patients

OBJECTIVES

To assess prevalence of headaches in patients with hemifacial spasm. To determine whether hemifacial spasm provokes headaches and identifies predictive factors. To evaluate whether botulinum toxin given for hemifacial spasm improves headaches.

METHODS

Seventy patients with hemifacial spasm were evaluated for headaches. The relationship of headaches with hemifacial spasm, impact on quality of life (HIT-6), and improvement in headaches from botulinum toxin was recorded. Data on duration, severity, and impact on quality of life (HFS-7) of hemifacial spasm were collected.

RESULTS

Hemifacial spasm-related headache was significantly associated with increased hemifacial spasm severity (P < 0.001) and HIT-6 (P = 0.024). Greater hemifacial spasm severity was predictive of hemifacial spasm-related headache (P = 0.006, OR 19.1, 95% CI 2.35-155.64). Botulinum toxin (BTX) for hemifacial spasm improved hemifacial spasm-related headaches (P < 0.001).

CONCLUSIONS

Hemifacial spasm can complicate headaches, particularly in patients with greater hemifacial spasm severity. Individually tailored regimens of botulinum toxin may be indicated in these patients.

Patients with idiopathic trigeminal neuralgia have a sharper-than-normal trigeminal-pontine angle and trigeminal nerve atrophy

BACKGROUND

Trigeminal neuralgia (TN) is primarily diagnosed by symptoms and patient history. Magnetic resonance (MR) imaging can be helpful in visualizing the neurovascular compression of the trigeminal nerve in TN patients, but the current parameters used as diagnostic markers for TN are less than optimal. The aim of this study is to assess whether the angle between the trigeminal nerve and the pons (the trigeminal-pontine angle) on the affected side of patients with idiopathic TN differs from that of the unaffected side and that found in controls without TN.

METHODS

A case-control study of 30 clinically diagnosed idiopathic TN patients aged 30 to 79 years and 30 age- and sex-matched controls was conducted. We compared the trigeminal-pontine angle and trigeminal nerve atrophy via fast-imaging employing steady-state acquisition (FIESTA) MR imaging.

RESULTS

A sharp trigeminal-pontine angle was observed in 25 patients (25/30) on the affected side. As such, the mean angle of the trigeminal nerve on the affected side (40.17) was significantly smaller than that on the unaffected side (48.91, p = 0.001) and that in the control group (52.02, p < 0.001).

CONCLUSIONS

A sharp trigeminal-pontine angle on the affected side was found in idiopathic TN patients by FIESTA imaging. This suggests that a sharp trigeminal-pontine angle increases the chance of neurovascular compression on the medial side of the trigeminal nerve.

Glucose hypermetabolism in the thalamus of patients with hemifacial spasm

The purpose of this study was investigate functional alteration in the brains of patients with hemifacial spasm using positron emission tomography (PET). We studied cerebral glucose metabolism using PET with (18) F-fluorodeoxyglucose in 13 patients with right lateral hemifacial spasm and 13 with left lateral hemifacial spasm. All patients underwent 2 PET scans before treatment (active state) and after treatment (suppressive state) with the botulinum neurotoxin type A. At the time of the PET scans, the severity of the spasm was rated according to the Jankovic Disability Rating Scale. We also used magnetic resonance imaging to evaluate the grade of neurovascular compression in each patient using scores of 1 to 3 (1 = mild, 3 = severe). Fifty-two normal volunteers were examined as controls. Compared with controls, patients with right and left hemifacial spasm showed bilateral cerebral glucose hypermetabolism in the thalamus in both the active and suppressive states. However, thalamic glucose metabolism after the suppressive state was significantly reduced compared with that in the active state using region of interest analysis. There was a positive correlation between the severity of the spasm in the active state and the score of neurovascular compression (rs = 0.65) that was estimated using Spearman order correlation coefficient. We observed bilateral cerebral glucose hypermetabolism in the thalamus of patients with hemifacial spasm. The thalamic glucose hypermetabolism may be attributed to multiple sources, including afferent input from the skin and muscle spindle, antidromic conduction of the facial nerve, and secondary alteration in the central nervous system.

Effect of botulinum neurotoxin treatment in the lateral spread monitoring of microvascular decompression for hemifacial spasm

INTRODUCTION

Botulinum neurotoxin (BtNtx) treatment for hemifacial spasm (HFS) prior to microvascular decompression (MVD) is hypothesized to be a factor in the variability of intraoperative neurophysiological monitoring (IONM) during this procedure.

METHODS

We analyzed 282 MVDs performed at the University of Pittsburgh Medical Center between January 1, 2000 and December 31, 2007. We retrospectively compared the lateral spread response (LSR) in the mentalis muscle when stimulus-triggered electromyography (EMG) was elicited from the facial nerve. Previous BtNtx treatment was the grouping factor.

RESULTS

Baseline LSR amplitudes during MVD (prior BtNtx: mean = 341.47 μV; no BtNtx: mean = 241.81 μV) were significantly different between groups (df = 1,281; t = -2.463; P = 0.014). Comparisons of latency and current threshold at baseline, as well as HFS disappearance or LSR persistence after the procedure, did not achieve statistical significance.

CONCLUSIONS

HFS patients treated with BtNtx prior to MVD demonstrated higher LSR baseline amplitudes during IONM. This could be related to muscle poly-reinnervation after recovery from repeated BtNtx use.

The many faces of hemifacial spasm: differential diagnosis of unilateral facial spasms

Hemifacial spasm is defined as unilateral, involuntary, irregular clonic or tonic movement of muscles innervated by the seventh cranial nerve. Most frequently attributed to vascular loop compression at the root exit zone of the facial nerve, there are many other etiologies of unilateral facial movements that must be considered in the differential diagnosis of hemifacial spasm. The primary purpose of this review is to draw attention to the marked heterogeneity of unilateral facial spasms and to focus on clinical characteristics of mimickers of hemifacial spasm and on atypical presentations of nonvascular cases. In addition to a comprehensive review of the literature on hemifacial spasm, medical records and videos of consecutive patients referred to the Movement Disorders Clinic at Baylor College of Medicine for hemifacial spasm between 2000 and 2010 were reviewed, and videos of illustrative cases were edited. Among 215 patients referred for evaluation of hemifacial spasm, 133 (62%) were classified as primary or idiopathic hemifacial spasm (presumably caused by vascular compression of the ipsilateral facial nerve), and 4 (2%) had hereditary hemifacial spasm. Secondary causes were found in 40 patients (19%) and included Bell's palsy (n=23, 11%), facial nerve injury (n=13, 6%), demyelination (n=2), and brain vascular insults (n=2). There were an additional 38 patients (18%) with hemifacial spasm mimickers classified as psychogenic, tics, dystonia, myoclonus, and hemimasticatory spasm. We concluded that although most cases of hemifacial spasm are idiopathic and probably caused by vascular compression of the facial nerve, other etiologies should be considered in the differential diagnosis, particularly if there are atypical features.

Hemifacial spasm

Hemifacial spasm (HFS) is a peripherally induced movement disorder causing clonic or tonic contractions of the facial muscles. HFS is usually unilateral and sporadic. It may be primary (mainly attributed to vascular compressions of the seventh cranial nerve in the posterior fossa) or secondary to facial nerve or brainstem damage. The two forms share a number of features but may differ in clinical presentation (simultaneous involvement of the upper and lower facial muscles in secondary forms). The spasm-related electromyogram activity is probably generated by ephaptic transmission, due to local demyelination at the entry zone of the facial nerve root (possibly owing to nerve damage caused by a compressing cerebral vessel). These findings suggest the "nerve origin hypothesis" as the main pathophysiological mechanism underlying HFS. Medical treatment (anticonvulsants or GABAergic drugs) is generally ineffective. Microvascular decompression of the facial nerve can achieve marked improvements in the majority of patients, although recurrences and complications are not uncommon. Local (orbicularis oculi or lower facial muscles) injection of Botulinum toxin (BoNT) is therefore considered the preferred symptomatic treatment for primary HFS. The long-term efficacy and safety of BoNT have been documented by clinical studies.

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.

Young onset hemifacial spasm

INTRODUCTION

Hemifacial spasm (HFS) frequently affects middle aged individuals and the clinical features and etiology have been well reported. However, there is limited data on the exact pathogenesis in young-onset HFS. If age is a major determinant of the etiology or influences the presentation of HFS, there may be clinical differences between the young and elderly HFS patients.

OBJECTIVES

We determined the prevalence, clinical and imaging features of young-onset HFS (age of onset<or=30 years) in a tertiary referral center. These data were compared with old onset (age of onset>or=65 years) HFS patients.

METHODS

We examined consecutive patients clinically diagnosed with HFS in a tertiary referral center. The clinical (demographics, clinical presentation, severity of HFS, associated medical conditions and other variables) and imaging findings of young onset patients and old onset patients were tabulated and compared.

RESULTS

Amongst 230 consecutive HFS patients, 15 (6.5%) were young-onset HFS and 50 (21.7%) were old-onset HFS. In the young-onset HFS, the mean age of onset of symptoms was 26.5+/-6.5 (6-30) years, with 80% women and 75.0% of young onset HFS having neurovascular compression (NVC) of the root exit zone (REZ) of the facial nerve on the ipsilateral side; 86.7% had initial onset of twitching in the upper eyelids that later progressed to the lower facial muscles. While the prevalence of hypertension, diabetes mellitus and other associated vascular disorders in late onset HFS was higher than in young onset groups, the clinical features and frequency of NVC of the facial REZ between the two groups were similar.

CONCLUSIONS

We demonstrated a 6.5% frequency of young-onset HFS in our cohort of HFS and their clinical presentation was similar to the old onset patients. Genetic, anatomic or other unidentified factors may contribute to NVC in young-onset HFS.

Botulinum toxin therapy of hemifacial spasm: comparing different therapeutic preparations

Hemifacial spasm (HFS) is characterized by involuntary irregular clonic or tonic movements of the muscles innervated by cranial nerve VII on one side of the face, and is most often a result of vascular compression of the facial nerve at the root exit zone (Muscle and Nerve 1998;21:1740). Disability associated with this disorder ranges from social embarrassment to interference with vision resulting from involuntary eye closure. Treatment of HFS most often involves botulinum toxin injections, but may also include medications and surgery. We describe treatment with the three types of botulinum toxin currently commercially available--Botox, Dysport and Myobloc/NeuroBloc.