顔面・頭頸部異常運動症に対する日本製A型ボツリヌス毒素注射療法の効果

Effect of Japanese-made botulinum A toxin injection in the management of facial-cervical abnormal movement disorders.

はじめに

　顔面，頭頸部にみられる異常運動症には顔面痙攣，眼瞼痙攣，痙性斜頸をはじめとして口角ジスキネジー，ミオキミア，眼性頭位異常，頭部振戦など，種々様々な疾患が含まれ，しかもそれらのほとんどは病因が不明であり，薬物治療や理学療法，心理療法など保存的治療に難渋する例が多い。われわれは1978年以来，顔面痙攣を中心として^9～11），これらの異常運動症に対し積極的に各種の手術療法を試みてきたが，顔面痙攣に対する神経血管減圧術以外は眼瞼痙攣に対するfacial neurotomy，斜頸に対するdifferential rhizotomyなどの手術治療に限界をみているのが現状である^31,39）。これら難治性の運動異常疾患に対し，われわれは最近，日本製A型ボツリヌス毒素注射療法を試み，良好なる成績を挙げつつあるので^40），ここに本毒素治療の概要を述べ，過去2年余のわれわれの成績を総括してみたい。

For the past 10 years, Schantz and Scott have been reporting satisfactory improvement of ocular muscular disorders such as strabismus and blepharospasm by injection of botulinum A toxin into the muscles. In 1987, we succeeded in producing a high specific activity botulinum A toxin in Japan and have performed clinical investigation of its use in the management of facial-cervical movement disorders. This report presents our 2 years' experience with injection of Japanese-made botulinum A toxin in 201 patients. There were 130 cases of essential blepharospasm, 37 cases of hemifacial spasm, 6 with post-paralytic facial synkinesis, 3 habit spasms, 3 oral-facial dyskinesias and 22 cases of spasmodic torticollis. The botulinum A toxin was diluted to 50 units/ml (1 unit=1 mouse intraperitoneal LD50) and 5 to 100 units of toxin were injected into the involved muscles of multiple locations such as orbicularis oculi, orbicularis oris, back neck muscles or sternocleidomastoid. EMG monotoring was used to confirm the appropriate injection sites. In a majority of cases with blepharospasm or facial spasm, excellent or good results were obtained and eye-lid spasms or facial twitching were almost disappeared. The effect of toxin was remarkable in localized small muscles such as orbicularis oculi, and not much so in larger extensive muscles such as back neck muscles contraction. A major disadvantage of the botulinum toxin injection therapy is diminution of its effect, generally after 2-4 months, that requires periodic repeated injections. Our present study has revealed that the Japanese-made botulinum A toxin has been very effective in alleviating intractable spasmodic contractions in most cases and that safety of its injection, even in multiple repeated high dosis, has been confirmed. There were no local sequelae, nor any allergic or systemic side effects. There were no serious neurological complications, except for 6 cases of tem-porary ptosis and 2 cases of transient mild facial weakness.