Hemifacial Spasm: Eyelid Twitching

Eyelid TwitchingTwitching of the faceThis patient is an atypical case of hemifacial spasm because he is a young college student only 29 years of age. Hemifacial spasm usually develops in the fifth and sixth decade of life and affects women more than men. It often begins insidiously in the orbicularis oculi muscle in the early stages, as in this case. This young man presented in 1973 for evaluation of twitching of his left eyelids and spasms of muscle twitching affecting the left cheek. Readily visible were contractions of the orbicularis oculi muscle which gradually spread to other muscles of the face, including the platysma. The paroxysms were induced or aggravated by voluntary and reflexive movements of the face. Past History: Negative for a previous lower motor neuron facial palsy (Bell's palsy). Investigations: Investigations in this patient, who was seen before the availability of MRI imaging, were directed towards ruling out: 1. A basilar artery aneurysm 2. An acoustic nerve tumor 3. Posterior fossa meningioma 4. Pontine glioma Because hemifacial spasm was frequently proved to be due to a compressive lesion of the facial nerve, by a tortuous branch of the basilar artery, a vertebral arteriogram was performed. Vertebral arteriogram showed: Compression of the left facial nerve root at the exit zone by a tortuous branch of the basilar artery that ran on the ventral surface of the pons and formed a loop under the facial nerve. Microsurgical decompression: In the early 1970's, at the time of this patient's presentation, Jannetta et al had introduced a microsurgical technique for decompressing the facial nerve in HS. The procedure involved the interposition of a pledget between the vessel and the nerve root, and this procedure was considered the treatment of choice in this patient. The surgery was performed by Dr. Robert Ojemann, Neurosurgeon, at the Massachusetts General Hospital. The operation was an immediate success with complete relief of HS (See second video clip). Microsurgical decompression of the facial nerve root has been corroborated by Barker et al in a series of 705 patients with HS followed post-operatively for an average of eight years. 84% achieved an excellent result. An even higher rate of benefit was obtained in a prospective series by Illingworth and colleagues (cure of 81of 83 patients). For a more recent study see ref 13.This patient with left sided HS has: • Almost continuous spasms of blinking of the left eyelids • Focal spasms of clonic/tonic synchronous contraction of the ipsilateral muscles In this patient HS was aggravated by: 1. Emotional stress 2. Fatigue 3. Active movement of the facial muscle and they HS persisted during sleep.Neuroimaging studies are not available in this patient. MRI images in another case are illustrated. Figure 1 Axial post-contrast TWI through the level of the internal auditory canals show a tortuous vertebrobasilar artery in the right cerebellopontine angle cistern abutting the facial nerve and root entry zone. Figure 2 Coronal post contrast T1W1 shows the tortuous right vertebral artery in the right cerebellopontine angle cistern adjacent to the facial nerve. Visualization of a vascular loop compressing the facial nerve in HS can also be demonstrated by 3D-phase contrast magnetic resonance angiography.Neurovascular compression syndrome causing deformity and demyelination of the 7th nerve.The pathophysiology of HS is believed to be focal demyelination nerve root compression. The demyelinated axon is thought to be responsible for activating adjacent nerve fibers by ephaptic transmission ("artificial" synapse of Granit et al). Nielsen and Jannetta have shown that ephaptic transmission disappears after the nerve is decompressed. Another possible source of the spasm is spontaneous ectopic excitation arising in injured fibers.Neurovascular compression of the facial nerve at its root exit zone from the brainstem.Medication: Carbamazepine (Tegretol) in a dose of 600 mg to 1200 mg per day has been found to control the spasm in two-thirds of patients. Baclofen or gabapentin is recommended if carbamazepine fails. Some patients cannot tolerate these drugs, have only brief remissions, or fail to respond. These cases may be treated with botulinum toxin injected into the orbicularis oculi and other facial muscles. Botulinum toxin therapy: Botulinum toxin relieves HS for a period of four to five months at which time the injections can be repeated without danger. Some patients have been injected repeatedly for more than five years without apparent adverse effects. Failing these conservative measures, surgery is then appropriate Microvascular decompression of the 7th nerve is the treatment of choice for neurovascular compression syndrome.1. Averbuch-Heller L. Neurology of the eyelids. Current Opinion in Ophthalmology 1997; 8:27-34. http://www.ncbi.nlm.nih.gov/pubmed/10176099 2. Barker FG, Jannetta PJ, Bissonette DJ, Shields PT, Larkins MV, Jho HD. Microvascular decompression for hemifacial spasm. J Neurosurg 1995;82:201-210. http://www.ncbi.nlm.nih.gov/pubmed/7815147 3. Granit R, Leskell L, Skogland CR. Fibre interaction in injured or compressed region of nerve. Brain 1944;67:125-140. 4. Illingworth RD, Porter DG, Jakubowski J. Hemifacial spasm: A prospective long-term follow-up of 83 patients treated by microvascular decompression. J Neurol Neurosurg Psychiatry 1996;60:72-77. http://www.ncbi.nlm.nih.gov/pubmed/8558156 5. Jannetta PJ. Posterior fossa neurovascular compression syndromes other than neuralgias . pp3227-3233. 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Vascular loop compressing facial nerve in hemifacial spasm: demonstrated by 3D-phase contrast magnetic resonance angiography in 101 patients. J Med Assoc Thai. 2004; Mar;87(3):219-224. http://www.ncbi.nlm.nih.gov/pubmed/15117036 11. Wang A, Jankovic J. Hemifacial spasm: clinical findings and treatment. Muscle Nerve. 1998 Dec;21(12):1740-1747. http://www.ncbi.nlm.nih.gov/pubmed/9843077 12. Wray SH. Blepharospasm Roundup. The 23rd Annual International Benign Essential Blepharospasm Research Foundation Conference, Park City Utah. August 2005 13. Yuan Y, Wang Y, Zhang SX, Zhang L, Li R, Guo J. Microvascular decompression in patients with hemifacial spasm: report of 1200 cases. Chin Med J (Engl). 2005 May 20;118(10):833-836. http://www.ncbi.nlm.nih.gov/pubmed/15989764curriculum_fellow; KBDhemifacialspasm; KBDfndhemifacialspasm; RStreatmentof; NOTE-EXAMblepharospas