Oberlin himself, justifying the randomized use of fascicles in his initial study, declares that at arm level, the ulnar nerve fascicles are mixed (with sensory and motor fibers). 3 Osman et al., 20 in a histomorphometric Paclitaxel microtubule study of the ulnar nerve and its branches, concluded that the ulnar nerve has 52% and 48% of sensory and motor fibers respectively; and that fascicles to the motor branch of the flexor digitorum profundus (FDP) muscle, represent 9.5% of the section area of the ulnar nerve, for which reason it is a good option for transfer and neurotization of the motor branch of the biceps brachii. Sungpet et al. 8 and Ferraresi et al., 10 using a nerve stimulator, seek to select motor fascicles for the flexor carpi ulnaris (FCU) muscle. Bertelli and Ghizoni; 9 Teboul et al.

11 and Shahriar-Kamrani et al. 12 use the nerve stimulator to select motor fascicles of any extrinsic flexor in order to preserve the innervation of the intrinsic muscles of the hand. Despite technical variations in the selection of the fascicles, the functional results and, especially, the absence of ulnar nerve deficit, are similar among authors. It can be stated that the fascicular definition of the ulnar nerve along its course in the arm should present a major variation among individuals; some having clearly differentiated motor and sensory fascicles at this level and others presenting this definition in more distal segments. We noticed that the nerve stimulator should be used at all times, but by means of inconclusive motor responses we should not penalize those that proceed in a random manner, in the selection of the fascicles; since the mode of selection of the fascicles does not change the results.

In patients with well-defined fascicles and with C7 deficit, preserving the branches to the FCU can be useful, targeting a future tendon transfer to reestablish the active extension of the fingers. In our series, the first signs of reinnervation appeared between two and six months. We observed in our patients that the early appearance of the reinnervation signs is also correlated with the final recovery of elbow flexion strength; patients who presented biceps contraction with MRC grade > 1 strength up to three months after surgery had the best long-term results. In the literature the first signs of reinnervation also appeared between two and six months after surgery, but the various authors cited did not correlate the early appearance of the contractions with the end results.

Frey states that the results of a neurotization distal to the brachial plexus are superior to those obtained by a proximal reconstruction, since the latter will prolong the reinnervation period and result in greater muscle atrophy. 21 The proximity of the ulnar nerve to the endplate of the biceps explains the early appearance of the reinnervation signs after Entinostat the Oberlin procedure. Such proximity also ensures a tension-free neurorrhaphy, which eliminates the need for grafts.