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

Abstract

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.

Mental health and quality of life in patients with craniofacial movement disorders: A cross-sectional study

“…Blepharospasm-oromandibular dystonia (BOD), which was first described by Meige in 1910 ( 9 ), is considered a type of Meige's syndrome ( 10 , 11 ). The accepted pathophysiology of HFS is ectopic firing and ephaptic transmissions originating in the root exit zone of the facial nerve ( 12 ), while basal ganglia dysfunction is common in Meige syndrome ( 8 ). Although the pathophysiology of these diseases is different, the clinical symptoms and treatment experiences of these patients share multiple similarities.…”

Child-onset Hemifacial Spasm-a case report

“…As we all know, HFS is a common cranial nerve disease, mainly manifested as involuntary convulsion of muscles innervated by facial nerve, the spasm could be provoked by mini stimulus, such as touching and light [4,18]. Studies have shown that HFS generally involves only unilateral face, mostly on the left side [5,24], and a few involves bilaterally or accompanied with other cranial nerve diseases, such as trigeminal neuralgia or glossopharyngeal neuralgia [25,26].…”

“…This disease usually occurs spontaneously and deteriorate as patients are stressful or fatigue [4], but also caused by mini stimulation. Generally speaking, HFS spasm involves only unilateral face [5], mainly the left side [3]. HFS could be divided into primary and secondary based on the potential etiology and primary HFS in majority of cases.…”

Successive occurrence of vertebrobasilar dolichectasia induced trigeminal neuralgia, vestibular paroxysmia and hemifacial spasm

“…Surgical treatment may be considered when the drug effect is unsatisfactory. At present, microvascular decompression [ 16 , 17 ] is the most effective surgical treatment. However, the surgical modes, operation skills, and difficulty of NVCS disease caused by VBD are far different, and the risk is higher than that caused by conventional vascular compression.…”