The anterior interosseous nerve syndrome (the Kiloh-Nevin syndrome). Report and follow-up study of three cases.

Three surgically treated cases demonstrate that this syndrome is a compressive neuropathy of the anterior interosseous branch of the median nerve rather than a neuritis, as originally believed. All symptoms were in the dominant hand and included deterioration of handwriting, pain, weakness of the flexor policis longus, the flexor digitorum longus to the index finger, and the pronator quadratus. Electromyograms were abnormal in two of the three cases. All forms of conservative treatment failed over a three- to five-month period. All lesions were demonstrable at surgery, and recovery was complete in all cases within five months of surgery. At an average follow-up evaluation of seven years there was no recurrence in any case. The loss of ability to write was characteristic of all three cases and is being reported for the first time.