Neurotization of the deep branch of ulnar nerve with anterior interosseous nerve: Anatomic study

Introduction. - The paralysis of the deep branch of ulnar nerve has major consequences on the motricity of the hand that will be felt as more handicapping by the patient than the sensory deficit. The current treatment of ulnar nerve lesions is suture or nerve graft in first intention and is essentially palliative in case of failure. We were interested in the anatomy of the anterior interosseous nerve and the deep branch of ulnar nerve to know if neurotization using direct suture of these two branches was possible in every case. Patients and methods. - Our anatomical study was done on 15 upper limbs. We dissected the branch of the anterior interosseous nerve innervating the pronator quadratus muscle and performed an intraneural dissection of the deep branch of ulnar nerve. The distance between these two branches was then measured. Results. - The mean distance separating the deep branch of ulnar nerve and the anterior interosseous nerve is 2.5 mm (-10-10). The direct suture of these two branches is possible in every case of this study. The macroscopic calibre of both branches is similar. Discussion. - Our study shows that the neurotization of the deep branch of ulnar nerve with the anterior interosseous nerve is possible in every case using direct suture, the wrist can be immobilised temporarily in flexion to reduce the tension. Ustun et al. as well as Wang and Zhu showed that their calibre and the number of axons is similar. We think that neurotization of the deep branch of ulnar nerve with the anterior interosseous nerve can be realized in first intention in case of high lesion of ulnar nerve. There is no major functional loss due to the paralysis of the pronator quadratus muscle. Conclusion. - Neurotization of the deep branch of ulnar nerve with the anterior interosseous nerve has no major functional loss and gives possible recovery of all the intrinsic muscles innervated by the deep branch of ulnar nerve. This neurotisation can be considered as an alternative to the usual techniques of direct suture or nerve graft, in case of lesion above mid forearm. (C) 2011 Elsevier Masson SAS. All rights reserved.