Temporal Bone Magnetic Resonance Imaging Study in Hemifacial Spasm

Transcription

1 Temporal Bone Magnetic Resonance Imaging Study in Hemifacial Spasm Sun Kon Kim, M.D., Jin Ho Kim, M.D., Jin Woo Yang, M.D., Hyun Jeong Lee, M.D., Tae Sub Cheong, M.D.*, Young Ho Sohn, M.D., Jin-Soo Kim, M.D., Myung Sik Lee, M.D. Department of Neurology and Neuroradiology*, Yongdong Severance Hospital Department of Neurology, Shinchon Severance Hospital, Yonsei University College of Medicine Department of Neurology, Chosun University College of Medicine Background : Hemifacial spasm (HS) has been attributed frequently to vascular compression of facial nerve root exit zone from brainstem. A recent brain CT scan study showed that patients with HS had narrower posterior fossa than normal controls. However, cause relationship between narrowed posterior fossa and vascular tortuosity is unknown. Methods : In 25 patients with HS and 29 controls, using temporal bone MRI, we measured petrous angle (PA) and pons diameter index (PDI) to define correlation between severity of posterior fossa narrowing and compression to brainstem. We compared severity of narrowing of posterior fossa between patients with and without tortuous arteries in posterior fossa. We also compared degree of narrowing of posterior fossa and clinical severity of HS. Results : The mean (standard deviation) of PA of 24 patients with HS ( ) was significantly smaller than that of controls ( ). The mean (standard deviation) of PDI of patients with HS ( %) was significantly greater than that of controls ( %). However, there was no correlation between PA and PDI in patients with HS. There was no correlation between degree of narrowing of posterior fossa and clinical severity of HS. Conclusions : Patients with HS have narrower posterior fossa as compared with controls. However, narrow posterior fossa does not seem to be a single important factor causing deformity of brainstem or tortuous arteries in posterior fossa. J Korean Neurol Assoc 18(3):304~310, 2000 Key Words : Hemifacial spasm, Temporal bone, MRI scan, Posterior cranial fossa Myung Sik Lee, M.D. 304 Copyright 2000 by the Korean Neurological Association

2 Table 1. Characteristics of 25 patients with hemifacial spasm clinical severity scale patient sex/age duration(years) side disability frequency severity total PA*(degree) PDI (%) 11 M/63 15 right F/54 15 left F/67 10 left F/51 10 left M/30 10 right M/43 10 left F/62 10 right M/52 6 left F/41 6 right F/56 5 right F/46 5 left F/ right F/60 4 left M/58 3 left F/42 3 right F/64 3 right M/47 3 right M/34 2 right F/39 2 left F/58 1 right F/24 1 left F/37 1 right F/53 1 left M/ left M/ right PA*; petrous angle PDI ; pons diameter index J Korean Neurol Assoc / Volume 18 / May,

3 Table 2. Severity scale for patients with hemifacial spasm 1. 1). 1 1). 1 2). 2 2). 2 3). 3 4). 4 ( ) 1). 1 ( ) 2). 2 1). 1 3) 3 2). 2. 3). 3 4). 4 5) ) ( >75%). 1 1). 1 2) (51%-75%). 2 2). 2 3) (26%-50%). 3 3). 3 4) (10%-25%). 4 5) ( <10%). 5 TV 1). 1 2) ). 3 1). 1 1). 1 2). 2 2). 2 3). 3 3). 3 4). 4 (shopping) 1). 1 1). 1 2). 2 2). 2 3). 3 3). 3 Adapted from Munsat TL. Quantification of neurologic deficit. Boston: Butterworth, 1989; J Korean Neurol Assoc / Volume 18 / May, 2000

4 Figure 1. The petrous angle (PA) is measured on T2 weighted axial brain MRI studies at the level of the internal auditory meatuses. The PA is defined as an angle between two lines connecting the middle point of posterior surface of the clivus to the posteromedial surface of bilateral petrous bones at the level of internal auditory meatuses. Figure 2. This figure shows the method measuring the pons diameter index (PDI) on T2 weighted axial brain MRI studies at the level of the internal auditory meatuses. The distance between the posterior surface of the clivus and the floor of the fourth ventricle (CF) and the distance between the ventral surface of the pons and the floor of the fourth ventricle (PF) are measured at the level of the internal auditory meatuses. The PDI is calculated as PF/CF100(%). J Korean Neurol Assoc / Volume 18 / May,

5 Table 3. Petrous angle and pons diameter index of controls and patients with hemifacial spasm controls patients n = 29 n = 25 petrous angle ( ) * ( ) ( ) pons diameter index (%) * ( ) ( ) PF (mm) ( ) ( ) CF (mm) ( ) ( ) PF; distance between ventral surface of the pons and floor of the fourth ventricle CF; distance between posterior surface of the clivus and floor the fourth ventricle pons diameter index (%) = PF/CF X 100 Numbers in the parenthesis = range meanstandard deviation *; p < 0.05 compare to the mean of controls Table 4. Petrous angle and pons diameter index of patients with hemifacial spasm with and without anatomical variations of the avteries (VoA) in the posterior fossa patients without VoA patients with VoA n = 8 n = 17 petrous angle ( ) * ( ) ( ) pons diameter index (%) * ( ) ( ) PF (mm) ( ) ( ) CF (mm) ( ) ( ) PF; distance between ventral surface of the pons and floor of the fourth ventricle CF; distance between posterior surface of the clivus and floor the fourth ventricle pons diameter index (%) = PF/CF X 100 Numbers in the parenthesis = range meanstandard deviation *; p > 0.05 compare to the mean of controls 308 J Korean Neurol Assoc / Volume 18 / May, 2000

6 01. Harper CM. AAEM Case report #21: hemifacial spasm; preoperative diagnosis and intraoperative management. Muscle Nerve 1991;14: Kraft SP, Lang AE. Cranial dystonia, blepharospasm and hemifacial spasm: Clinical features and treatment, including the use of botulinum toxin. Can Med Assoc J 1988;139: Jannetta PJ. Cranial rhizopathies. In: Youmans JR, 3rd eds. Neurological surgery. Philadelphia: Saunders 1990; Samii M, Jannetta PJ. The cranial nerves: anatomy, pathology, pathophysiology, diagnosis, treatment. Berlin: Springer-Verlag 1981; Montagna P, Imbriaco A, Zucconi M, Liguori R, Cirignotta F, Lugaresi E. Hemifacial spasm in sleep. Neurology 1986;36: Jannetta PJ. Trigeminal neuralgia and hemifacial spasm: etiology and definitive treatment. Arch Neurol 1975 ; 32 : Jannetta PJ, Abbasy M, Maroon JC, Ramos FM, Albin MS. Etiology and definitive microsurgical treatment of hemifacial spasm; operative techniques and results in 47 patients. J Neurosurg 1977;47: Maroon JC. Hemifacial spasm; a vascular cause. A r c h Neurol 1978;35: Loeser JD, Chen J. Hemifacial spasm: Treatment by microsurgical facial nerve decompression. N e u r o s u r g e r y 1983;13: Auger RG, Piepgras DG, Laws ER Jr. Hemifacial spasm: Results of microvascular decompression of the facial nerve in 54 patients. Mayo Clin Proc 1986;61: Moller AR, Jannetta PJ. Monitoring facial EMG responses during microvascular decompression operation for hemifacial spasm. J Neurosurg 1987;66: Kamiguchi H, Ohira T, Ochiai M, Kawase T. Computed tomographic analysis of hemifacial spasm: narrowing of the posterior fossa as a possible facilitating factor for neu- rovascular compression. J Neurol Neurosurg Psychiatry 1997;62: Munsat TL. Quantification of neurologic deficit. Boston: Butterworth 1989; Nakamura Y, Nakatsukasa M, Ibata Y, Yamaki JT, Ohira T, Takase M, et al. Clinicophysiological study of multi- modality evoked potentials and computed tomographic findings in persistent vegetative state. Brain and Nerve 1988;40: Adler CH, Zimmerman RA, Savino PJ, Bernardi B, J Korean Neurol Assoc / Volume 18 / May,

7 Bosley TM, Sergott RC. Hemifacial spasm: Evaluation by magnetic resonance imaging and magnetic resonance tomographic angiography. Ann Neurol 1992;32: Du C, Korogi Y, Nagahiro S, Sakamoto Y, Takada A, Ushio Y, et al. Hemifacial spasm: three dimensional MR images in the evaluation of neurovascular compression. Radiology 1995;197: Girard N, Poncet M, Caces F, Tallon Y, Chays A, Martin- Bouyer P, et al. Three dimensional MRI of hemifacial spasm with surgical correlation. N e u r o r a d i o l o g y 1997;39: Hosoya T, Watanabe N, Yamaguchi K, Saito S, Nakai O. Three dimensional MRI of neurovascular compression in patients with hemifacial spasm. N e u r o r a d i o l o g y 1995;37: Carlos R, Fukui M, Hasuo K, Uchino A, Matsushima T, Tamura S, et al. Radiological analysis of hemifacial spasm with special reference to angiographic manifestations. Neuroradiology 1986;28: Tanaka A, Tanaka T, Irie Y, Yoshinaga S, Tomonaga M. Elevation of the petrous bone caused by hyperplasia of the occipital bone presenting as hemifacial spasm: diagnostic values of magnetic resonance imaging and three dimensional computed tomographic images in a bone anomaly. Neurosurgery 1990;27: Gardner WJ, Dohn DF. Trigeminal neuralgia-hemifacial spasm-paget s disease: significance of this association. Brain 1966;89: Clarke CRA, Harrison MJG. Neurological manifestations of Paget s disease. J Neurol Sci 1978;38: Nishi T, Matsukado Y, Nagahiro S, Fukushima M, Koga K. Hemifacial spasm due to contralateral acoustic neuroma: case report. Neurology 1987;37: Rhee BA, Kim TS, Kim GK, Leem W. Hemifacial spasm caused by contralateral cerebellopontine angle meningioma: case report. Neurosurgery 1995;36: Matsuura N, Kondo A. Trigeminal neuralgia and hemifacial spasm as false localizing signs in patients with a contralateral mass of the posterior cranial fossa: Report of three cases. J Neurosurg 1996;84: J Korean Neurol Assoc / Volume 18 / May, 2000