Microvascular Decompression in Hemifacial Spasm: Intraoperative Electrophysiological Observations

Abstract Facial muscle responses in patients with hemifacial spasm undergoing microvascular decompression operations were recorded. Two peripheral branches of the facial nerve were stimulated and the electrical responses of muscles innervated by these branches were studied to see how the lateral spread of activity that is known to be present in these patients was affected by decompressing the facial nerve. In some of the patients the hemifacial spasm ceased when the dura mater was opened, in some it ceased when the arachnoid was opened, and in others the spasm persisted until the offending vessel was dissected away from the nerve. The lateral spread of activity elicited by antidromic stimulation of a branch of the facial nerve was less affected by opening of the dura mater or arachnoid: it usually persisted until the blood vessel that had been compressing the facial nerve was removed and reappeared when the vessel that had been compressing the facial nerve was allowed to slip back onto the nerve. This seems to indicate that microvascular decompression of the facial nerve is effective in alleviating hemifacial spasm because it removes the actual cause of the disorder rather than simply causing local injury to the nerve as a result of the procedure.

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Monitoring facial EMG responses during microvascular decompression operations for hemifacial spasm

Journal of Neurosurgery ◽

10.3171/jns.1987.66.5.0681 ◽

1987 ◽

Vol 66 (5) ◽

pp. 681-685 ◽

Cited By ~ 125

Author(s):

Aage R. Møller ◽

Peter J. Jannetta

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Lateral Spread ◽

Emg Activity ◽

Content Type ◽

Facial Emg ◽

Lateral Spread Response ◽

Fine Print ◽

Stimulation Of

✓ Facial electromyographic (EMG) responses were monitored intraoperatively in 67 patients with hemifacial spasm who were operated on consecutively by microvascular decompression of the facial nerve near its exit from the brain stem. At the beginning of the operation, electrical stimulation of the temporal or the zygomatic branch of the facial nerve gave rise to a burst of EMG activity (autoexcitation) and spontaneous EMG activity (spasm) that could be recorded from the mentalis muscle in all patients. In some patients, the spontaneous activity and the autoexcitation disappeared after the dura was incised or when the arachnoid was opened, but stimulation of the temporal branch of the facial nerve caused electrically recordable activity in the mentalis muscle (lateral spread) with a latency of about 10 msec that lasted until the facial nerve was decompressed in all but one patient, in whom it disappeared when the arachnoidal membrane was opened. When the facial nerve was decompressed, this lateral spread of antidromic activity disappeared totally in 44 cases, in 16 it was much reduced, and in seven it was present at the end of the operation at about the same strength as before craniectomy. In four of these last seven patients there was still very little improvement of the spasm 2 to 6 months after the operation; these four patients underwent reoperation. In two of the remaining three patients, the spasm was absent at the 3- and 7-month follow-up examination, respectively, and one had mild spasm. Of the 16 patients in whom the lateral spread response was decreased as a result of the decompression but was still present at the end of the operation, 14 had no spasm and two underwent reoperation and had mild spasm at the last examination. Of the 44 patients in whom the lateral spread response disappeared totally, 42 were free from spasm and two had occasional mild spasm at 6 and 13 months, respectively, after the operation. Monitoring of facial EMG responses is now used routinely by the authors during operations to relieve hemifacial spasm, and is performed simultaneously with monitoring of auditory function for the purpose of preserving hearing. The usefulness of monitoring both brain-stem auditory evoked potentials recorded from electrodes placed on the scalp and compound action potentials recorded directly from the eighth cranial nerve is evaluated.

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Electrophysiological investigation of hemifacial spasm after microvascular decompression: F waves of the facial muscles, blink reflexes, and abnormal muscle responses

Journal of Neurosurgery ◽

10.3171/jns.1997.86.4.0654 ◽

1997 ◽

Vol 86 (4) ◽

pp. 654-661 ◽

Cited By ~ 45

Author(s):

Mami Ishikawa ◽

Takayuki Ohira ◽

Jun Namiki ◽

Masato Kobayashi ◽

Moriichiro Takase ◽

...

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Lateral Spread ◽

Motor Nucleus ◽

Additional Surgery ◽

Facial Motor Nucleus ◽

Lower Amplitude ◽

Before And After ◽

Muscle Responses

✓ In patients with hemifacial spasm, it has been said that the spasm is due to cross compression of the facial nerve by a blood vessel and that microvascular decompression (MVD) of the facial nerve is an effective treatment. The F waves, which result from backfiring of antidromically activated motor neurons of the facial motor nucleus, are indices of the excitability of the facial motor nucleus and are enhanced in patients with hemifacial spasm. Measuring blink reflexes and abnormal muscle responses (lateral spread), a characteristic sign of hemifacial spasm, has been used to investigate the mechanism of hemifacial spasm pathophysiologically. Thus the authors measured F waves of the facial muscle, blink reflexes, and abnormal muscle responses before and after MVD in patients suffering from hemifacial spasm to investigate the excitability of the facial motor nucleus and the course of the cure of hemifacial spasm after MVD. The authors obtained facial nerve—evoked electromyograms in 20 patients with hemifacial spasm before and after the MVD procedure. On the spasm side, the F waves and blink reflexes were enhanced preoperatively compared to those on the normal side and abnormal muscle responses were recorded in all patients. In 12 patients whose hemifacial spasm had not disappeared completely for 5.1 ± 1.7 (mean ± standard error) months following the MVD procedure, F waves were still enhanced significantly and abnormal muscle responses were still recordable, albeit at lower amplitude. Within 1 month after the hemifacial spasm had disappeared completely, F waves were still significantly enhanced in 17 patients and abnormal muscle responses were recorded in seven of 15 patients. Subsequently, the enhanced F waves and abnormal muscle responses disappeared completely. The authors' study supports the hypothesis that the cause of hemifacial spasm is hyperexcitability of the facial motor nucleus and suggests that additional surgery should not be performed for at least 2 years after MVD, because that period is necessary for the disappearance of the hyperexcitability of the facial motor nucleus.

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Magnetically Evoked Facial Nerve Potential

Otolaryngology ◽

10.1177/019459988910000417 ◽

1989 ◽

Vol 100 (4) ◽

pp. 345-347 ◽

Cited By ~ 7

Author(s):

Ian M. Windmill ◽

Serge A. Martinez ◽

Christopher B. Shields ◽

Markku Paloheimo

Keyword(s):

Electrical Stimulation ◽

Facial Nerve ◽

Nerve Stimulation ◽

Magnetic Stimulation ◽

Electrical Current ◽

Facial Muscle ◽

Facial Nerve Stimulation ◽

Muscle Responses ◽

Stimulation Of

Facial nerve stimulation by electrical current is painful and tends to discourage serial studies. Transcutaneous magnetic stimulation of the facial nerve is painless, easily reproducible, and elicits facial muscle responses identical to electrical stimulation.

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Endoscopic-Assisted Microvascular Decompression of Ectatic Vertebral Artery for Hemifacial Spasm: Operative Video and Technical Nuances

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0039-1688807 ◽

2019 ◽

Vol 80 (S 03) ◽

pp. S312-S313

Author(s):

James K. Liu ◽

Vincent N. Dodson

Keyword(s):

Facial Nerve ◽

Vertebral Artery ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Lateral Spread ◽

Microsurgical Decompression ◽

Root Exit Zone ◽

Hearing Function ◽

Endoscopic Assistance ◽

Lateral Spread Response

In this operative video atlas manuscript, the authors demonstrate the operative nuances and surgical technique for endoscopic-assisted microvascular decompression of a large ectatic vertebral artery causing hemifacial spasm. A retrosigmoid approach was performed and a large ectatic vertebral artery was transposed away from the root exit zone of cranial nerve VII (Fig. 1). The lateral spread response disappeared, signifying adequate decompression of the facial nerve (Fig. 2). The use of endoscopic-assistance during the microsurgical decompression was very useful to confirm the origin and also the resolution of neurovascular conflict. Postoperatively, the patient experienced immediate resolution of hemifacial spasm with normal facial nerve and hearing function. Written consent was obtained from the patient to publish videos, photographs, and images from the surgery.The link to the video can be found at: https://youtu.be/RlMz44uCDCw.

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Lateral spread response of different facial muscles during microvascular decompression in hemifacial spasm

Clinical Neurophysiology ◽

10.1016/j.clinph.2021.07.020 ◽

2021 ◽

Author(s):

Minsoo Kim ◽

Sang-Ku Park ◽

Seunghoon Lee ◽

Jeong-A Lee ◽

Kwan Park

Keyword(s):

Hemifacial Spasm ◽

Microvascular Decompression ◽

Lateral Spread ◽

Facial Muscles ◽

Lateral Spread Response

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Microvascular Decompression of the Facial Nerve for the Treatment of Hemifacial Spasm: Preoperative Magnetic Resonance Imaging Related to Clinical Outcomes

Acta Neurochirurgica ◽

10.1007/s007010070076 ◽

2000 ◽

Vol 142 (8) ◽

pp. 901-907 ◽

Cited By ~ 37

Author(s):

S. S. Chung ◽

J. W. Chang ◽

S. H. Kim ◽

J. H. Chang ◽

Y. G. Park ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Facial Nerve ◽

Clinical Outcomes ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Preoperative Magnetic Resonance Imaging ◽

Resonance Imaging ◽

Preoperative Magnetic Resonance

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Retrosigmoid Craniotomy for the Removal of Left Sided Tentorial and Posterior Fossa Meningioma Combined with Microvascular Decompression for Hemifacial Spasm

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0038-1675167 ◽

2018 ◽

Vol 80 (S 03) ◽

pp. S294-S295

Author(s):

Yu-Wen Cheng ◽

Chun-Yu Cheng ◽

Zeeshan Qazi ◽

Laligam N. Sekhar

Keyword(s):

Facial Nerve ◽

Hemifacial Spasm ◽

Microvascular Decompression ◽

Preoperative Imaging ◽

Superior Cerebellar Artery ◽

Anterior Inferior Cerebellar Artery ◽

Root Exit Zone ◽

Tentorial Meningioma ◽

Cerebellar Artery ◽

The Right

This 68-year-old woman presented with repeated episodes of bilateral hemifacial spasm with headache for 5 years and with recent progression of left sided symptoms. Preoperative imaging showed a left sided tentorial meningioma with brain stem and cerebellar compression. Left facial nerve was compressed by the vertebral artery (VA) and the right facial nerve by the anterior inferior cerebellar artery (AICA). This patient underwent left side retrosigmoid craniotomy and mastoidectomy. The cisterna magna was drained to relax the brain. The tumor was very firm, attached to the tentorium and had medial and lateral lobules. The superior cerebellar artery was adherent to the lateral lobule of the tumor and dissected away. The tumor was detached from its tentorial base; we first removed the lateral lobule. Following this, the medial lobule was also completely dissected and removed. The root exit zone of cranial nerve (CN) VII was dissected and exposed. The compression was caused both by a prominent VA and AICA. Initially, the several pieces of Teflon felt were placed for the decompression. Then vertebropexy was performed by using 8–0 nylon suture placed through the VA media to the clival dura. A further piece of Teflon felt was placed between cerebellopontine angle region and AICA. Her hemifacial spasm resolved postoperatively, and she discharged home 1 week later. Postoperative imaging showed complete tumor removal and decompression of left CN VII. This video shows the complex surgery of microsurgical resection of a large tentorial meningioma and microvascular decompression with a vertebropexy procedure.The link to the video can be found at: https://youtu.be/N5aHN9CRJeM.

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