Pain syndrome and focal myokymia due to anterior interosseous neurovascular relationships: report of a case and neurophysiological considerations.

The anterior interosseous nerve can become entrapped within the antecubital fossa at its origin from the median nerve, which results in the so-called Kiloh-Nevin syndrome. In this report, the authors describe an atypical anterior interosseous nerve syndrome due to neurovascular relationships with the anterior interosseous artery. The patient complained of unbearable analgesic-resistant pain within the forearm and focal myokymia in muscles innervated by branches of the anterior interosseous and distal median nerves. Pain and myokymia were alleviated by inflated blood pressure cuff compression in the bicipital region when the arterial pulse was abolished distally. Microsurgical correction of the pulsatile arterial compression resulted in relief from pain and myokymia. Neurophysiological considerations of the mechanism underlying "irritative" neuropathy and myokymia are discussed.