[Electromyographical and clinical follow up study of brachial plexus lesions (author's transl)]

21 cases of brachial plexus lesions were reexamined clinically and electromyographically after a posttraumatic interval of 3 to 11 years. In accordance with Brooks (1) recovery--as judged by muscle strength, sensation and amount of EMG activity during volontary action--was relatively good in upper plexus lesions, fair in middle plexus lesions and very poor in lower plexus lesions (Fig. 1 A, B). Even in cases of incomplete lower plexus lesions with small residual innervation initially, recovery was only moderate (Fig. 1 C). The tendency for reinnervation decreased with increasing distance of target muscles from the lesion site in the plexus (Fig. 2). Motor and sensory deficits in corresponding dermaresp. myotomes were either congruent or more frequently incongruent with prevalence of motor deficits (Fig. 3). Earliest electromyographical signs of reinnervation were observed after 4 to 9 months (upper and middle plexus lesion). Reinnervation of proximal muscles was completed after 11 months to 2 years (Fig. 4). Posttraumatically regenerated nerve fibers had often decreased conduction velocities (some values as low as 7 m/sec) and showed sometimes abnormal target muscles leading to paradoxical innervation and synkinesias between antagonistic muscles.