[Traumatic lesions of the deep branch of the radial nerve].

PURPOSE OF THE STUDY

We report a retrospective study of 21 patients treated for an injury of the deep branch of the radial nerve. The aim of this study was to precise the indication and to evaluate the results of nerve surgery and tendon transfer.

MATERIAL

21 patients, mean age 32, with complete divided lesion of the nerve due to open injury were included. 5 cases with fresh discision of the deep branch of the radial nerve were treated in emergency by suture repair. 16 cases were old lesions. 6 of them had initially severe associated lesions involving skin, forearm muscles or radius. In this case, the treatment of the nerve lesion was delayed after the treatment of the associated lesions. 10 were simple lesions of the nerve who were initially misknowned (6 cases) or caused by a surgical procedure at the proximal forearm (4 cases).

METHODS

4 patients had tendon transfers, due to a very old lesion for one of them and a severe muscle involvement for the 3 others. Twelve nerve graft repairs were performed. Their were 8 troncular grafts and 4 fascicular grafts because the lesion was in the posterior forearm at the level of the terminating branches of the nerve. They required a mean length of 5.8 cm and an average of 3 to 4 cables for nerve graft.

RESULTS

The mean follow up was 25 months. Results were appreciated on the recovery of 5 functions (supination, fingers extension, thumb abduction, thumb retropulsion, wrist postero-ulnar extension). Primitive nerve repairs had full recovery in all cases. Tendon transfers had good results. The 12 nerve grafts had 2 excellent results, 8 good results, 1 fair and 1 poor result. These 2 last cases required secondary tendon transfers.

DISCUSSION

Traumatic lesions of the deep branch of the radial nerve are often misknowned and often iatrogenic. Nerve surgery provides better functional results than tendon transfers. Nerve grafts in delayed nerve repairs are possible even if the lesion is distal. They give excellent or good functional recovery in most cases after a delay of 7 months. Tendon transfers are indicated if nerve surgery fails or in case of large forearm muscle defect, old patient, and when the delay after the injury is superior to 12 months.