筋電義手普及の現状と課題，高位切断者に対する戦略，そして今後の展望

Myoelectric Prostheses : Current Status and Problems to be Solved, a Rehabilitation Strategy for Higher Level Amputation Patients, and the Future Outlook

はじめに

　現在の日本において筋電義手を入手するために利用可能な公的支援制度は2つ存在する．労働者災害補償保険法による研究用支給制度（2008年4月1日にようやく試行開始され，継続中）と自立支援法による特例補装具制度である．公的制度が整備されてきてはいるようであるが，筋電義手訓練を提供できる施設が極めて少ないなど臨床面での整備が追い付いておらず，筋電義手の普及はほとんど進んでいないのが現実である．参考までに筋電義手の普及状態を欧米諸国と比較すると，片側前腕切断者に限れば，義手の中で筋電義手の占める割合は，アメリカで25～40％，ドイツで70％，イタリアで16％であり^1），日本では僅か2％であった^2）．

　日本で筋電義手を普及させるためには何が必要で，何をなすべきかについてはいろいろと議論のあるところであるが，重要なことは「我々臨床家がすべての起点である」という自負を持つことである．臨床家がリーダーシップを発揮し，行政にその必要性を訴え，そして工学者と連携することでより良い開発が可能となる．本稿が筋電義手の明るい未来を創造するためのヒントとなれば幸いである．

Abstract : Rehabilitation using myoelectric prosthesis for trans-radial amputees has become wide spread and well established in several developed countries. However, the clinical use of myoelectric prostheses for trans-radial amputees has not yet spread in Japan. It is well known that once amputees become accustomed to using their prosthesis efficiently through adequate rehabilitation, that various activities which the amputees had given up so far will become possible through enhanced bimanual activities. Although myoelectric prostheses have proved to be useful, the majority of amputees have not been satisfied with their function. As an amputee becomes a better user, they request not only simple tasks but also complicated ones. As a consequence, the amputee comes to know the limits of their myoelectric prosthesis, thus expectations for superior prostheses will arise. The recent remarkable development of engineering technology has enabled the progress of prosthetic limb technology, leading to the production of far superior functional prostheses which meet the user's expectations. However, there is a paradox in developing such superior prostheses. The more advanced the prosthesis we produce, the higher the cost. To achieve this end, it is absolutely imperative to secure the cooperation of both clinicians and engineers. Furthermore, a rehabilitation strategy for patients with a higher level of amputation (trans-humeral amputation, shoulder disarticulation) remains unsolved. In this paper, we propose a “Hybrid Myoelectric Prosthesis”, which consists of a myoelectric hand as a terminal device and a body-powered active elbow joint, as a realistic solution for higher level amputees. In addition, we introduce Targeted Reinnervation (TR) as a future strategy for reference.