Journal ArticleForty-six patients with typical hemifacial spasm had CT. Thirty-eight (83%) were abnormal, including two with surgically documented tumors. Thirty-six had a characteristic dolichoectatic vertebrobasilar artery, with the convexity pointing to the side of the spasm in 92% of the scans. This study suggests that CT is worthwhile procedure in the evaluation of hemifacial spasm and that dolichoectatic vertebrobasilar arteries are very frequently associated with hemifacial spasm

Corbett, James J.

Digre, Kathleen B.

English

journal articleForty-six patients with typical hemifacial spasm had CT. Thirty-eight (83%) were abnormal, including two with surgically documented tumors. Thirty-six had a characteristic dolichoectatic vertebrobasilar artery, with the convexity pointing to the side of the spasm in 92% of the scans. This study suggests that CT is worthwhile procedure in the evaluation of hemifacial spasm and that dolichoectatic vertebrobasilar arteries are very frequently associated with hemifacial spasm

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cuoleabl I dYBtro, 419-424-i neutral i08ifonn rlIlatol , lIlyopa. 13. In: Str. nPreaa, Wi TM, rage dia.. aroni P, ,of eJec. eurology c acid ia ellweger hy·Proc I neutral roblast&. li8lIland roblast&. aannR, 1. StlJtt. ,on AR. th lipid es. Arch olman'• ury JB, basis of 303-819. md acid olman's lin Med neutral Biophya '<fetaho-ystemic ochem CT and hemifacial spasm Kathleen B. Digre, MD; James J. Corbett, MD; Wendy R.K. Smoker, MD; and Shauna McKusker, MD Article abstract-Forty-six: patients with typical hemifacial spasm had CT. Thirty-eight (83%) were abnormal, includ-ingtwo with surgically documented tumors. Thirty-six: had a characteristic dolichoectatic vertebrobasilar artery, with the convexity pointing to the side of the spasm in 92% of the scans. This study suggests that CT is a worthwhile procedure in the evaluation of hemifacial spasm and that dolichoectatic vertebrobasilar arteries are very frequently associated with . hemifacial spasm. -Hemifacial spasm (HFS) is a movement disorder of the face characterized by frequent, involuntary twitches of muscles innervated by the seventh cranial nerve. Al-though the disorder has been characterized as idio-pathic, many neurosurgeons have reported vascular loops compressing the seventh nerve at the nerve root exit zone.1•4 Infrequently, tumors have been associated with HFS as well. There have been reports of abnormal eTs with HFS,5.g but there has never been a prospective study with CT for this condition. Materials and methods. Patients had CT who presented to the neurology and ophthalmology departments from 1980 to June 1987 with a diagnosis of typical HFS. Initially, three patients had unenhanced scans, but since vessels are better identified using contrast enhancement, contrast was used in all later scans. Scans were reviewed prospectively for abnor-malities. We later reviewed all of the scans again, without clinical information. We tried to predict the side of the spasm by looking at the posterior fossa for abnormalities of vessels, tumors, and other malformations. Results. Between 1980 and 1987, we identified 46 peo-ple with HFS. There were 27 women and 19 men. Ages ranged from 22 to 85, with a mean of 64.2 years. There were 19 with right, 26 with left, and one with bilateral HFS. Thirty-eight scans (83%) were abnormal, including two with surgically documented tumors-an epider-moid and a meningioma. Thirty-six scans showed a characteristic dolichoectatic basilar artery. We defined dolichoectatic basilar artery in accordance with the definition proposed by Smoker et a1. 9,10 There were only eight normal scans. Two of the three noncontrast-en-hanced CTs were among these. Of the other 36 abnormal scans, which we read in a NEUROLOGY 1988;38:1111-1113 masked fashion, we identified the side of the HFS by the direction of the convexity of the dolichoectatic basilar artery in 33 of 36 (92%) scans. Discussion. HFS was described as an idiopathic disor-der in the pastH ; however, many of these early studies did not have the benefit of radiologic techniques, and a cause was never found. A neurosurgical nerve wrapping procedure is used for this condition, and surgeons have reported frequently that vessels (vertebral, basilar, and, more frequently, anterior inferior cerebellar artery [AICAl and posterior inferior cerebellar artery [PICA] or their small branches) were sitting on the seventh nerve root exit zone. l ,3 Gardner and Sava12 first reported cases with the vertebrobasilar system compressing the seventh facial nerve in 1962. Since then there have been many reports of similar findings.2,7,12'15 Sunderland16 reported inci-dental dolichoectatic arteries of the basilar system in 22% of autopsied brains he reviewed; no clinical correla-tion was ever made. Sacks and Lindenburg17 popu-larized the term "dolichoectatic" vertebral and basilar arteries. Recently, Smoker et a19 reviewed dolichoectatic basilar arteries on CTs and published criteria for defining the diameter, height of the bifurcation, and transverse position of the normal basilar artery from a review of 126 normal CTs in patients ranging from 4 to 85 years old. They found the basilar artery is mid-line throughout its course in 55% of cases, but still medial to the lateral margin of the clivus or dorsum sellae in 43% of cases. In only 2% of normal cases was the vertebrobasilar artery visualized lateral to the clivus or dorsum sellae, and in no normal case was it as far lateral as the cerebellopontine angle (CPA) cistern. In the second part of their study, symptom-From the Departmenta of Neurology (Drs. Digre and Corbett) and Ophthalmology (Drs. Digre, Corbett, and McKuaker), University ofIowa, Iowa City, lA; and the Department of Radiology (Dr. Smoker), University of Utah, Salt Lake City, UT. Dr. Digre was supported by a Heed Ophthalmic Foundation Fellowship (1986·1987). This work was al60 supported by an un.restricted grant from Research to Prevent 8lindne88, University of Iowa. Received August 20, 1987. Accepted for pUblication in final form December 2,1987. Addre88 correspondence and reprint requesta to Dr. Corbett, Department of Neurology, University of Iowa Hospitals and Clinics, Iowa. City, lA 52242. July 1988 NEUROLOGY 38 1111 atic patients were evaluated. lO Isolated cranial nerve deficits were more likely to be present with normal-sized but malposition ed, tortuous vessels. Patients with dilatation (ectasia) of the basilar artery more commonly have multiple compressive cranial nerve and ischemic neurologic deficits (locked-in and Wal-lenberg syndromes, hemiplegia, dysarthria, dys-phonia, hyperreflexia, ataxia, etc).l0 Six patients in their study had isolated HFS. In all cases, the distal vertebral or proximal basilar artery was visualized in the CPA cistern of the affected side. lO Figure 1. One tumor causing hemifacial spasm: a man with an epidermoid tumor in the left cerebellopontine angle causing left hemifacial spasm. Carlos et al5 more recently demonstrated tortuous and dilated arteries by arteriography in 51 patients with HFS. They commented that there was a dolichoectatic basilar artery in the CPA in three CTs; however, how many other patients had any dolichoectasia of the ver. tebrobasilar system was unclear. Their angiographic findings of frequent anomalous branching of AICA and PICA, as well as frequent elongation of the vertebral system, support our findings. I We propose that HFS is commonly associated with I .a tortuous and elongated vertebrobasilar system. The exact way in which this causes the spasm is unknown I I but we would postulate that there are two possibl~ mechanisms. First, direct compression by the ver- . tebral or basilar artery might be possible. Vessels distorting the nerve root exit zone could trigger such a spasm. Obviously, all CTs do not show the basilar artery at the CPA, and this probably is not the only mechanism. Second, branch vessels, especially the AICA and PICA, frequently abut the nerve in this location. The convexity of the vertebrobasilar system usually points to the side of the HFS. It may be that the tortuous and elongated artery pushes other tribu- Fig! tary branches into the nerve root exit zone. Other basi studies support this possibility.5.7 We think contrast-enhanced CT is an important diagnostic procedure in evaluation of a patient for HFS, ner since we discovered two unsuspected tumors whose sole rou presenting feature was HFS. Second, in recommending ass I treatment, especially surgical, knowledge of the possible I aberrant vessel is necessary. I' HFS was at one time considered an idiopathic dis- . order. With the advent of CT and other new imaging Re techniques, it is possible to detect a probable cause for L the spasm in 83% of the cases. With high field- .. l.. strength magnetic resonance, the seventh cranial 2.] 3. ] 4. J 5.1 6. ; 7. 8. ( I Figure 2. Representative CTs of patients with right hemifacial spasm. The arrows point to the convexity of the dolichoectatic l' basilar artery. 1112 NEUROLOGY 38 July 1988 . - -uous with tatic how Ver_ lphic -and :bral with The OWn, sible ver-ssels leha silar only , the this ~tem that 'ibu- Figure 3. Representative CTs of patients with left hemifacial spasm. The arrows point to the convexity of the dolichoectatic Ither basilar artery. i.ant fFS, !sole ,ding sible dis-,ging efor ield-mial tatic nerve is usually visualized, and the relationship sur-rounding the vascular structures may be even better assessed. I References , i LJannetta PJ. Neurovascular compression in cranial nerve and systemic disease. Ann Surg 1980;192:518-525. 2. Kerber CW, Margolis MT, Newton TH. Tortuous vertebrobasilar system: a cause of cranial nerve signs. Neuroradiology 1972;4:74-77. 3. Nell.goy DR, Dohn BF. Hemifacial spasm secondary to vascular compression of the facial nerve. Cleve Clin Q 1974;41:205-214. 4. Eckman PB, Kramer RA, Altrocchi PH. Hemifacial spasm. Arch NeuroI1971;25:81-87. 5, Carlos R, Fukui M, Hasuo K, et al. Radiological analysis of hemi-facial spasm with special reference to angiographic manifesta-tions. Neuroradiology 1986;28:288-295. 6.Sobel D, Norman D, Yorke CH, Newton TH. Radiography of trigeminal neuralgia and hemifacial spasm. AJR 1980;135:93-95. 7. Bagot d'Arc M, Paiva A, Darrouzet V, Maia R, Bebear JP. Hemi-spasme facial revelateur d'une dolicho-ectasie du tronc basilaire. Revue de Laryngologie 1984;105:53-55. 8. Deeb ZL, Jannetta PJ, Rosenbaum AE, Kerber CW, Drayer BP. Tortuous vertebrobasilar arteries causing cranial nerve syn-dromes: screening by computed tomography. J Comp Assist To-mogr 1979;3:774-778. 9. Smoker WRK, Price MJ, Keyes WD, Corbett JJ, Gentry LR. High-resolution computed tomography of the basilar artery. I. Normal size and position. AJNR 1986;7:55-60. 10. Smoker WRK, Corbett JJ, Gentry LR, Keyes WD, Price MJ, McKusker S. High-resolution computed tomography of the basilar artery. II. Vertebrobasilar dolichoectasia: clinical-patho-logic correlation and review. AJNR 1986;7:61-72. 11. Ehni G, Woltman HW. Hemifacial spasm. Arch Neurol Psychia-try 1945;53:205-211. 12. Gardner W J, Sava G. Hemifacial spasm: a reversible pathophysio-logic state. J Neurosurg 1962;19:240-247. 13. Gibson WPR, Wallace B. Basilar artery ectasia (an unusual cause of a cerebello-pontine lesion and hemifacial spasm). J Laryngol OtoI1975;89:721-731. 14. KatfNY, Tatlow WIT. Two cases of vertebral-basilar aneurysm. Can Med Assoc J 1965;92:471-474. 15. Nappi G, Moglia A, Poloni M, Arrigo A. Hemifacial spasm associ-ated with dolichomegavertebrobasilar anomaly. Eur Neurol 1977;15:94-101. 16. Sunderland S. Neurovascular relations and anomalies at the base of the brain. J Neurol Neurosurg Psychiatry 1948;11:243-257. 17. Sacks JG, Lindenburg R. Dolicho-ectatic intracranial arteries: symptomatology and pathogenesis of arterial elongation and dis-tention. Johns Hopkins Med J 1969;125:95-106. 

CT and hemifacial spasm.

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CT and hemifacial spasm.

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