脳卒中後の上肢痙縮への2度のA型ボツリヌス毒素投与が上肢運動機能へ与える効果

Clinical Efficacy of a Double Injection Protocol of Botulinum Toxin Type A for Upper Limb Hemiparesis after Stroke

要旨　目的：脳卒中後の上肢痙縮に対し2度，A型ボツリヌス毒素（BoNT-A）を投与し，その効果を検討した．方法：2度のBoNT-A投与を受け，それぞれの投与前後で評価を実施できた慢性期脳卒中患者112名（55.5±11.6歳，平均±SD）を対象とした．麻痺側上肢の複数の痙縮筋に対して，3カ月以上間隔をあけBoNT-Aを2回投与し，自主トレーニングを指導した．各々の投与前，投与1カ月後と3カ月後に，改訂Ashworthスケール（MAS），関節角度（肢位）（ROM），Fugl-Meyer Assessment（FMA）の上肢各項目を評価した．結果：FMA総計，下位項目AとB，MASは，初回投与前後のみならず，初回投与後と2度目投与後との比較でも，有意な改善を認めた（p＜0.05）．下位項目Dは，2度目投与前後で有意に改善した（p＜0.05）．結論：2度のBoNT-A投与で，痙縮の軽減のみならず上肢運動機能で更なる改善を認めた．訓練を継続した上でBoNT-A投与を繰り返すことの重要性が示唆された．

Abstract　Background : The aim of this study was to assess the effects of repeated injections of botulinum toxin type A (BoNT-A) combined with a rehabilitative program for treating spastic upper limb hemiparesis after stroke. Subjects and methods : Subjects were 112 poststroke hemiparetic patients with spastic upper limb (mean age : 55.5±11.6 years ±SD, mean period between onset and first injection : 5.1±3.5 years). For each patient, BoNT-A (maximum dose of each injection : 240 units) was injected in the spastic muscles of the affected upper limb twice with a minimum interval of 3 months. Following each injection, detailed one-to-one instructions for home-based functional training was provided. At the baseline (before injection) and at 1 and 3 month follow-ups after each injection, the patient's modified Ashworth scale (MAS), the range of motion (ROM) and Fugl-Meyer Assessment (FMA) were evaluated. Results : The total score for the upper limb and the scores of categories A and B of the FMA increased significantly not only after the first injection but after the second injection compared with the second baseline, while the FMA score for category D increased significantly only after the second injection. MAS also decreased significantly not only after the first injection but after the second injection compared to the second baseline. Conclusion : A more significant improvement was found not only in muscle spasticity but also in upper limb motor function after two BoNT-A injections. It is suggested that repeated BoNT-A injections followed by a comprehensive rehabilitative program would be an effective treatment for limb spasticity after a stroke.