肋間神経交差移行術を施行した腕神経叢全型引き抜き損傷例における障害側上肢の深部感覚機能の検討

Assessment of the functioning of deep sensation in the upper extremities of patients with the complete root-avulsion-type brachial plexus injuries treated by the intercostal nerve crossing method

要旨：筋皮神経への肋間神経交差移行術により神経再支配を受けた上腕二頭筋に，良好な筋力が得られた腕神経叢全型引き抜き損傷例を対象に深部感覚検査を行い，術後に獲得される深部感覚機能について検討した．深部感覚検査の結果は，「肩か肘か試験」，「上か下か試験」，肘単独施行の「模倣試験」では正しく回答できたが，「45°か90°か試験」，肩肘組合せ施行の「模倣試験」，「母指さがし試験」，「肘頭さがし試験」では誤答が目立った．本術後に獲得される深部感覚機能は代償的な学習によるものであり，それも肩，肘どちらの動きかの識別と肘関節単独の肢位および運動方向の感知に限られていた．これらの深部感覚は，外側前腕皮神経(筋皮神経知覚技)から肋間神経を介しての大脳皮質感覚野(前胸壁部)への投射と，残存する肩周囲および腋窩部の知覚情報の両者から形成されていると考えられた．

　In this study, we tested the functioning of deep sensation in the upper limb of patients with complete root-avulsion-type brachial plexus injuries, which were treated by using the intercostal nerve crossing method, and then we examined the postoperative improvement of deep sensation. The results of "shoulder/elbow test", "upward/downward test", and "imitation test of elbow movements only" showed correct responses. However, we obtained incorrect responses from the "45°/90° test, "imitation test of simultaneous movements of shoulder and elbow", "thumb localizing test", and "olecranon localizing test".

　These tests proved that the deep sensation recovery is limited to the distinction of shoulder movement from the elbow movement and sensing the elbow position and direction of the elbow movements. As a result, we can conclude that these deep sensations were produced by a combination of messages sent from the anterior thorax via the intercostal nerve from the lateral cutaneous nerve of the forearm with the sensory information remaining in the area around the shoulder and axilla.