Experimental Monkey Model of Hemifacial Spasm and Electrophysiological Study of Mechanism Participating with Hemifaical Spasm

Research Project

Project/Area Number	63570676
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Cerebral neurosurgery
Research Institution	Yamanashi Medical College
Principal Investigator	NAGASEKI Yoshishige Yamanashi Medical College, Neurosurgery, Research Associate, 医学部脳神経外科, 助手 (80172534)
Co-Investigator(Kenkyū-buntansha)	HORIKOSHI Tohru Yamanashi Medical College, Neurosurgery, Research Associate, 医学部脳神経外科, 助手 (50209300) FUKAMACHI Akira Yamanashi Medical College, Neurosurgery, Assistant Professor, 医学部脳神経外科, 助教授 (60008555) UENO Takehiko Yamanashi Medical College, Neurosurgery, UCHIDA Mikito Yamanashi Medical College, Neurosurgery,
Project Period (FY)	1988 – 1989
Project Status	Completed (Fiscal Year 1989)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1989: ¥900,000 (Direct Cost: ¥900,000) Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords	Trigeminal neuralgia / Hemifacial spasm / Microvascular decompression / Abnormal electrical activity / Experimental model / 実験的モデル
Research Abstract	As the management for essential trigeninal neuralgia (TN) and Hemifacial spasm (HFS), microvascular decompression (MVD) of the trigenianl nerve or facial nerve at their root entry zones was established by P. Jannetta since 1966. But the etiological mechanisms are controversial, because where the origin of the abnormal electrical activities are, is unclear. For example, it is speculated that the origins are in the cross-compressed lesion (the peripheral theory) or in the facial motonucleus (central theory). Therefore, we have been tried making experimental model of HFS in monkey two years ago for clarifying the mechanism. We thought that HFS appeared by making the nerve compression induced by silicon tube between the facial nerve and the skull base in the pathophysiologic status like HFS in human. We utilized 3 monkeys (weight of 3-4 Kg). Each monkey was seated in the monkey chair and microscopically operated by suboccipital craniectomy with Ketaral anesthesia (i.m) and 0.5% Xylocaine l … More ocal anesthesia. During the operation, the cerebellum was retracted by brain retractor and the facial nerve was exposed. Then we inserted a silicon tube (1mm diameter and 1cm length) in one monkey , rubber in the same size like the former in one monkey and a tube in the same size making of Gore-Tex surgical membrane in the residual monkey respectively, between the facial nerve and the skull base. After these manipulation we could recognized the fluctuation of the nerve with the brain stem. Furthermore, intraoperative face EMGs were monitored and face VTRs were recorded. We carefully observed the changes of facial status for seven months in one monkey, six months in one monkey and four months in the residual monkey. However, HFS have never been recognized in each monkey. The former two monkeys were died caused by other general diseases. Though we examined two brains and facial nerves stained for Nissl substance using cresyl violet, the degeneration and/or anatomical changes were riot confirmed. From now on, we will continue these trials developing the experimental methodology. Less