Hemifacial Spasm

Eyelid Twitching; Hemifacial SpasmPowerPoint Presentation: Hemifacial Spasm : http://library.med.utah.edu/NOVEL/Wray/PPT/Hemifacial_Spasm.ppt Shirley H. Wray, M.D., Ph.D., FRCP Harvard Medical SchoolTwitching EyelidsThe patient is a 72 year old man with myopia, childhood exotropia, progressive age related ptosis and right hemifacial spasm. Hemifacial spasm (HS) most often begins insidiously in the orbicularis oculi muscle in the early stages, as in this man. He presented with a 2 year history of involuntary twitching of the right upper eyelid, which he described as "a quiver". The twitching slowly progressed to involve the ipsilateral facial muscles. On some occasions the twitching was almost continuous and he sat watching television with his hand over his right eye. His hemifacial spasms were aggravated by emotional stress and fatigue and precipitated by active movement of any facial muscle. Just asking him to show his teeth provoked right sided facial spasm. Past History: Negative for trauma, a previous lower motor neuron facial palsy (Bell's Palsy), impaired sensation of the face and face pain. He had no history of deafness or tinnitus. Investigations: Electromyography: Electromyographic study confirmed that the HS was due to brief bursts of normal motor units firing at high frequency. (HS is not a focal dystonia). Brain MRI is required in these cases to rule out: 1. A basilar artery aneurysm 2. An acoustic nerve tumor 3. Posterior fossa meningioma 4. Pontine glioma Brain MRI with contrast showed: A small enchancing vessel crossing the root entry zone of the right 7th and 8th cranial nerve. No corresponding vessel was noted on the controlateral side. Diagnosis: Neurovascular compression syndrome of the facial nerve root Microsurgical decompression: Microsurgical decompression of the facial nerve root was recommended but, not unexpectedly, the patient declined because of the risks of a posterior craniotomy. Botulinum toxin therapy: He was referred to the Movement Disorder Clinic for treatment with Botulinum toxin (BT). BT injections successfully suppressed the HS in this patient and he continued receiving this treatment on a routine basis over many months.This elderly patient with right sided HS has: • Twitching of the right lower eyelid which, at first glance, may be confused with benign fasciculations, a movement disorder confined to the eyelids. • Once the eyelid twitching starts it can be seen to set off movements of the ipsilateral facial muscles producing twitching of the cheek and the angle of the mouth The focal spasms affecting the face are characterized by paroxysmal involuntary clonic and tonic synchronous contraction of the muscles innervated by the facial nerve.Neuroimaging studies are not available in this patient. MRI images in another case are illustrated. Figure 1 Axial post-contrast TW1 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 of the facial (7th cranial) 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 may be 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. Microsurgical Decompression: Microvascular decompression of the facial nerve root is the treatment of choice when a small vascular loop of an arterial branch of the basilar artery is compressing the facial nerve. Jannetta et al introduced microsurgical decompression of the facial nerve root with the interposition of a pledget between the vessel and the nerve as a successful procedure for relief of HS in the early 1970s. The success of the procedure was corroborated by Barker et al in a series of 705 patients 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 81 of 83 patients). For a more recent study see ref 13.1. 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. In: Wilkins RH, Rengachary SS eds: Neurosurgery 2nd ed. McGraw-Hill, New York 1996. 6. Miwa H, Kondo T, Mizuno Y. Bell's palsy-induced blepharospasm. J Neurol. 2002 Apr;249(4):452-454. http://www.ncbi.nlm.nih.gov/pubmed/11967652 7. Nielsen VK, Jannetta PJ. Pathophysiology of hemifacial spasm : Effects of facial nerve decompression. Neurology 1984;34:891-897. http://www.ncbi.nlm.nih.gov/pubmed/6330612 8. Schmidtke K, Buttner-Ennever JA. Nervous Control of Eyelid Function. A review of clinical, experimental and pathological data. Brain 1992; 115:227-247. http://www.ncbi.nlm.nih.gov/pubmed/1559156 9. Sindou MP. Microvascular decompression for primary hemifacial spasm. Importance of intraoperative neurophysiological monitoring. Acta Neurochir (Wien) 1005;147 (10):1019-1026. http://www.ncbi.nlm.nih.gov/pubmed/16094508 10. Suthipongchai S, Chawalparit O, Churojana A, Poungvarin N. 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; EXAMblepharospasm; NOTE-EXAMblepharospas