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.

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Neurovascular compression findings in hemifacial spasm

Journal of Neurosurgery ◽

10.3171/jns/2008/109/9/0416 ◽

2008 ◽

Vol 109 (3) ◽

pp. 416-420 ◽

Cited By ~ 119

Author(s):

Mauricio Campos-Benitez ◽

Anthony M. Kaufmann

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Nerve Root ◽

Posterior Inferior Cerebellar Artery ◽

Anterior Inferior Cerebellar Artery ◽

Vascular Compression ◽

Neurovascular Compression ◽

Exit Point ◽

Root Exit Zone ◽

Cerebellar Artery

Object It is generally accepted that hemifacial spasm (HFS) is caused by pulsatile vascular compression upon the facial nerve root exit zone. This 2–3 mm area, considered synonymous with the Obersteiner–Redlich zone, is a transition zone (TZ) between central and peripheral axonal myelination that is situated at the nerve's detachment from the pons. Further proximally, however, the facial nerve is exposed on the pontine surface and emerges from the pontomedullary sulcus. The incidence and significance of neurovascular compression upon these different segments of the facial nerve in patients with HFS has not been previously reported. Methods The nature of neurovascular compression was determined in 115 consecutive patients undergoing their first microvascular decompression (MVD) for HFS. The location of neurovascular compression was categorized to 1 of 4 anatomical portions of the facial nerve: RExP = root exit point; AS = attached segment; RDP = root detachment point that corresponds to the TZ; and CP = distal cisternal portion. The severity of compression was defined as follows: mild = contact without indentation of nerve; moderate = indentation; and severe = deviation of the nerve course. Success in alleviating HFS was documented by telephone interview conducted at least 24 months following MVD surgery. Results Neurovascular compression was found in all patients, and the main culprit was the anterior inferior cerebellar artery (in 43%), posterior inferior cerebellar artery (in 31%), vertebral artery (in 23%), or a large vein (in 3%). Multiple compressing vessels were found in 38% of cases. The primary culprit location was at RExP in 10%, AS in 64%, RDP in 22%, and CP in 3%. The severity of compression was mild in 27%, moderate in 61%, and severe in 12%. Failure to alleviate HFS occurred in 9 cases, and was not related to compression location, severity, or vessel type. Conclusions The authors observed that culprit neurovascular compression was present in all cases of HFS, but situated at the RDP or Obersteiner–Redlich zone in only one-quarter of cases and rarely on the more distal facial nerve root. Since the majority of culprit compression was found more proximally on the pontine surface or even pontomedullary sulcus origin of the facial nerve, these areas must be effectively visualized to achieve consistent success in performing MVD for HFS.

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Hemifacial spasm caused by vascular compression of the distal portion of the facial nerve

Journal of Neurosurgery ◽

10.3171/jns.1998.88.3.0605 ◽

1998 ◽

Vol 88 (3) ◽

pp. 605-609 ◽

Cited By ~ 34

Author(s):

Hiroshi Ryu ◽

Seiji Yamamoto ◽

Kenji Sugiyama ◽

Kenichi Uemura ◽

Tsunehiko Miyamoto

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Cranial Nerve ◽

Distal Portion ◽

Vascular Compression ◽

Neurovascular Compression ◽

Content Type ◽

Seventh Cranial Nerve ◽

Neurovascular Decompression ◽

Fine Print

✓ It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve.

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Hemifacial Spasm Caused by Vascular Compression in the Cisternal Portion of the Facial Nerve: Report of Two Cases with Review of the Literature

Case Reports in Neurological Medicine ◽

10.1155/2019/8526157 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Byung-chul Son ◽

Hak-cheol Ko ◽

Jin-gyu Choi

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Essential Element ◽

Distal Segment ◽

Lateral Spread ◽

Anterior Inferior Cerebellar Artery ◽

Vascular Compression ◽

Neurovascular Compression ◽

Mri Imaging ◽

Facial Nerves

Although primary hemifacial spasm (HFS) is mostly related to a vascular compression of the facial nerve at its root exit zone (REZ), its occurrence in association with distal, cisternal portion has been repeatedly reported during the last two decades. We report two patients with typical HFS caused by distal neurovascular compression, in which the spasm was successfully treated with microvascular decompression (MVD). Vascular compression of distal, cisternal portion of the facial nerve was identified preoperatively in the magnetic resonance imaging (MRI). It was confirmed again with intraoperative findings of compression of cisternal portion of the facial nerve by the meatal loop of the anterior inferior cerebellar artery (AICA) and absence of any offending vessel in the REZ of the facial nerve. Immediate disappearance of lateral spread response (LSR) after decompression and resolution of spasm after the operation again validated that HFS in the current patients originated from the vascular compression of distal, cisternal portion of the facial nerves. According to our literature review of 64 patients with HFS caused by distal neurovascular compression, distal compression can be classified by pure distal neurovascular compression (31 cases, 48.4%) and double compression (both distal segment and the REZ of the facial nerves, 33 cases [51.6%]) according to the presence or absence of simultaneous offender in the REZ. Eighty-four percent of 64 identified distal offenders were the AICA, especially its meatal and postmeatal segments. Before awareness of distal neurovascular compression causing HFS and sophisticated MRI imaging (before 2000), the rate of reoperation was high (58%). Preoperative MRI and intraoperative monitoring of LSR seems to be an essential element in determination of real offending vessel in MVD caused by distal offender.

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Hemifacial Spasm Caused by a Venule: Case Report

Neurosurgery ◽

10.1227/00006123-198401000-00021 ◽

1984 ◽

Vol 14 (1) ◽

pp. 89-92 ◽

Cited By ~ 35

Author(s):

Peter J. Jannetta

Keyword(s):

Case Report ◽

Facial Nerve ◽

Blood Vessels ◽

Hemifacial Spasm ◽

Vascular Compression ◽

Entry Zone ◽

Root Entry Zone ◽

Facial Spasm ◽

Posterior Direction ◽

Anterior Posterior

Abstract The syndrome of hemifacial spasm occurs as a consequence of compression, almost universally by blood vessels, of the root entry zone of the facial nerve. The vascular compression is usually obvious at operation, but may be subtle. The author describes a case in which a venule running in an anterior-posterior direction across the caudal aspect of the root entry zone of the facial nerve, which was thought to be causing the spasm, was coagulated and divided. A small, more distal arteriole, probably not contributory, was decompressed away from the nerve. After operation, the patient improved gradually, and she remains free of facial spasm or weakness. This is the most subtle vascular compression seen by the author and his colleagues in over 400 microvascular decompressions for hemifacial spasm.

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Prevalence and severity of neurovascular compression in hemifacial spasm patients

Brain ◽

10.1093/brain/awab030 ◽

2021 ◽

Author(s):

Katie S Traylor ◽

Raymond F Sekula ◽

Komal Eubanks ◽

Nallammai Muthiah ◽

Yue-Fang Chang ◽

...

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Cranial Nerve ◽

Odds Ratio ◽

Imaging Study ◽

Severe Form ◽

Vascular Compression ◽

Neurovascular Compression ◽

Classical Trigeminal Neuralgia ◽

Symptomatic Side

Abstract Hemifacial spasm is typically caused by vascular compression of the proximal intracranial facial nerve. Although the prevalence of neurovascular compression has been investigated in a cohort of patients with classical trigeminal neuralgia, the prevalence and severity of neurovascular compression has not been well characterized in patients with hemifacial spasm. We aimed to investigate whether presence and severity of neurovascular compression are correlated to the symptomatic side in patients with hemifacial spasm. All patients in our study were evaluated by a physician who specializes in the management of cranial nerve disorders. Once hemifacial spasm was diagnosed on physical exam, the patient underwent a dedicated cranial nerve protocol magnetic resonance imaging study on a 3 T scanner. Exams were retrospectively reviewed by a neuroradiologist blinded to the symptomatic side. The presence, severity, vessel type, and location of neurovascular compression along the facial nerve was recorded. Neurovascular compression was graded as contact alone (vessel touching the facial nerve) versus deformity (indentation or deviation of the nerve by the culprit vessel). A total of 330 patients with hemifacial spasm were included. The majority (232) were female while the minority (98) were male. The average age was 55.7 years. Neurovascular compression (arterial) was identified on both the symptomatic (97.88%) and asymptomatic sides (38.79%) frequently. Neurovascular compression from an artery along the susceptible/proximal portion of the nerve was much more common on the symptomatic side (96.36%) than on the asymptomatic side (12.73%), odds ratio = 93.00, P < 0.0001. When we assessed severity of arterial compression, the more severe form of neurovascular compression, deformity, was noted on the symptomatic side (70.3%) much more frequently than on the asymptomatic side (1.82%) (odds ratio = 114.00 P < 0.0001). We conclude that neurovascular compression that results in deformity of the susceptible portion of the facial nerve is highly associated with the symptomatic side in hemifacial spasm.

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Hemifacial spasm secondary to middle ear cholesteatoma

Ear Nose & Throat Journal ◽

10.1177/014556131809700602 ◽

2018 ◽

Vol 97 (6) ◽

pp. E31-E32

Author(s):

Maheep Sohal ◽

Nicholas Karter ◽

Marc Eisen

Keyword(s):

Facial Nerve ◽

Middle Ear ◽

Hemifacial Spasm ◽

Final Diagnosis ◽

Computed Tomographic Angiography ◽

Vascular Compression ◽

Computed Tomographic ◽

Middle Ear Cholesteatoma ◽

Facial Spasm ◽

Tomographic Angiography

Hemifacial spasm is a peripheral myoclonus of the VIIth cranial nerve that is characterized by paroxysmal contraction of the muscles of facial expression. It exists in both primary and secondary forms. In rare cases, hemifacial spasm is caused by middle ear pathology. We describe the case of a 90-year-old man with recurrent cholesteatoma and tympanic segment fallopian canal dehiscence manifesting as right-sided hemifacial spasm. His history was significant for a right-sided tympanomastoidectomy for cholesteatoma 6 years earlier. Computed tomographic angiography performed to look for vascular compression of the facial nerve demonstrated a right middle ear opacification. Middle ear exploration revealed a completely dehiscent tympanic segment with cholesteatoma abutting the facial nerve. The overlying keratin debris and matrix were carefully dissected off, and facial nerve function was preserved. The final diagnosis was hemifacial spasm. During 14 months of postoperative follow-up, the patient experienced no further facial spasm.

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Classification of neurovascular compression in typical hemifacial spasm: three-dimensional visualization of the facial and the vestibulocochlear nerves

Journal of Neurosurgery ◽

10.3171/jns-07/12/1154 ◽

2007 ◽

Vol 107 (6) ◽

pp. 1154-1163 ◽

Cited By ~ 43

Author(s):

Ramin Naraghi ◽

Levent Tanrikulu ◽

Regina Troescher-Weber ◽

Barbara Bischoff ◽

Martin Hecht ◽

...

Keyword(s):

Mr Imaging ◽

Facial Nerve ◽

Volume Rendering ◽

Hemifacial Spasm ◽

Three Dimensional ◽

Neurosurgical Procedures ◽

Neurovascular Compression ◽

Direct Volume Rendering ◽

Vestibulocochlear Nerve ◽

Cerebellar Artery

Object In this paper, the authors introduce a method of noninvasive anatomical analysis of the facial nerve–vestibulocochlear nerve complex and the depiction of the variable vascular relationships by using 3D volume visualization. With this technique, a detailed spatial representation of the facial and vestibulocochlear nerves was obtained. Patients with hemifacial spasm (HFS) resulting from neurovascular compression (NVC) were examined. Methods A total of 25 patients (13 males and 12 females) with HFS underwent 3D visualization using magnetic resonance (MR) imaging with 3D constructive interference in a steady state (CISS). Each data set was segmented and visualized with respect to the individual neurovascular relationships by direct volume rendering. Segmentation and visualization of the facial and vestibulocochlear nerves were performed with reference to their root exit zone (REZ), as well as proximal and distal segments including corresponding blood vessels. The 3D visualizations were interactively compared with the intraoperative situation during microvascular decompression (MVD) to verify the results with the observed microneurosurgical anatomy. Results Of the 25 patients, 20 underwent MVD (80%). Microvascular details were recorded on the affected and unaffected sides. On the affected sides, the anterior inferior cerebellar artery (AICA) was the most common causative vessel. The posterior inferior cerebellar artery, vertebral artery, internal auditory artery, and veins at the REZ of the facial nerve (the seventh cranial nerve) were also found to cause vascular contacts to the REZ of the facial nerve. In addition to this, the authors identified three distinct types of NVC within the REZ of the facial nerve at the affected sides. The authors analyzed the varying courses of the vessels on the unaffected sides. There were no bilateral clinical symptoms of HFS and no bilateral vascular compression of the REZ of the facial nerve. The authors discovered that the AICA is the most common vessel that interferes with the proximal and distal portions of the facial nerve without any contact between vessels and the REZ of the facial nerve on the unaffected sides. Conclusions Three-dimensional visualization by direct volume rendering of 3D CISS MR imaging data offers the opportunity of noninvasive exploration and anatomical categorization of the facial nerve–vestibulocochlear nerve complex. Furthermore, it proves to be advantageous in establishing the diagnosis and guiding neurosurgical procedures by representing original MR imaging patient data in a 3D fashion. This modality provides an excellent overview of the entire neurovascular relationship of the cerebellopontine angle in each case.

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“Macrovascular” Decompression of Dolichoectatic Vertebral Artery Causing Hemifacial Spasm Using Goretex Sling: 2-Dimensional Operative Video

Operative Neurosurgery ◽

10.1093/ons/opy111 ◽

2018 ◽

Vol 16 (2) ◽

pp. 267-268 ◽

Cited By ~ 4

Author(s):

Stephan A Munich ◽

Jacques J Morcos

Keyword(s):

Facial Nerve ◽

Vertebral Artery ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Orbicularis Oculi ◽

Entry Zone ◽

Common Cause ◽

Root Entry Zone ◽

Offending Artery ◽

Key Steps

Abstract Hemifacial spasm is characterized by painless and involuntary spasms of the muscles supplied by the facial nerve, most commonly involving the orbicularis oculi. The most common cause of hemifacial spasm is compression of the facial nerve's root by the anterior inferior, or posterior inferior, cerebellar arteries (AICA or PICA). However, in <1% of cases, the compression can be due to a dolichoectatic vertebral artery. Microvascular decompression using Teflon patties may be sufficient when the offending artery is small (eg, AICA or PICA). However, the size and tortuosity of the vertebral artery (especially one that is dolichoectatic) may require a more robust means of decompression (ie, “macrovascular decompression”). In this operative video we demonstrate our technique for managing a patient with hemifacial spasm due to a dolicoectatic vertebral artery. We use a Goretex® (W.L. Gore & Associates Inc, Newark, Delaware) sling secured to the dura of the posterior petrous ridge to suspend the vertebral and posterior inferior cerebellar arteries, thereby decompressing the root entry zone of the facial nerve. Teflon felt pieces are added as a second layer of security. Key steps to this technique include: (1) visualization of the root entry zone, (2) extensive arachnoid dissection to allow adequate mobilization of the vertebral artery, 12 and (3) securing the sling in a trajectory that prevents kinking of the vertebral artery and its branches.

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Hemifacial spasm

Journal of Neurosurgery ◽

10.3171/jns.1982.57.6.0753 ◽

1982 ◽

Vol 57 (6) ◽

pp. 753-756 ◽

Cited By ~ 77

Author(s):

Tsutomu Iwakuma ◽

Akihisa Matsumoto ◽

Nishio Nakamura

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Nerve Root ◽

Posterior Inferior Cerebellar Artery ◽

Content Type ◽

Stylomastoid Foramen ◽

Root Exit Zone ◽

Selective Neurectomy ◽

Fine Print

✓ Patients with hemifacial spasm were treated by three different surgical procedures: 1) partial sectioning of the facial nerve just distal to the stylomastoid foramen; 2) selective neurectomy of facial nerve branches; and 3) microvascular decompression. A retromastoid craniectomy with microvascular decompression was most effective in relieving hemifacial spasm and synkinesis. In a postmorten examination on one patient, microscopic examination of the facial nerve, which was compressed by an arterial loop of the posterior inferior cerebellar artery at the cerebellopontine angle, revealed fascicular demyelination in the nerve root. On the basis of surgical treatment, electromyography, and neuropathological findings, the authors conclude that compression of the facial nerve root exit zone by vascular structures is the main cause of hemifacial spasm and synkinesis.

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