Microsurgery
-
The goal of this study was to determine the functional axonal anatomy of a termino-lateral neurorrhaphy (TLN). We hypothesize that axons populating a TLN must relinquish functional connections with their original targets prior to establishing new connections via the TLN. Two-month-old F344 rats underwent a TLN between the left peroneal nerve and a nerve graft tunneled to the contralateral hindlimb. ⋯ Left peroneal nerve stimulation proximal to the TLN site resulted in bilateral extensor digitorum longus (EDL) and tibialis anterior (TA) muscle contractions, with significantly lower forces on the side reinnervated by TLN. Evoked EMGs demonstrated that the right and left hindlimb musculature were electrically discontinuous following TLN. These data support our hypothesis that axons can form functional connections via a TLN, but they must first relinquish functional connections with their original targets.
-
This article studies the utilization of the end-to-side neurorrhaphy concept in the prevention and treatment of painful neuromas. A total of 20 rats were divided into 2 groups (10 rats per group). In group A, the tibial nerve was divided and left lying in the subcutaneous tissue. ⋯ In group B, the proximal end of the tibial nerve formed a "non-classic" neuroma and the nerve healed into the peroneal nerve with continuity of the epineurium of the 2 nerves. The distal end of the tibial nerve in group B showed evidence of axonal regeneration. Preliminary clinical experience utilizing the same technique in the prevention and treatment of painful neuromas of the superficial radial nerve is presented and other techniques of nerve-to-nerve implantation are discussed.
-
The mechanism of end-to-side neurorrhaphy is believed to be by collateral sprouting, although evidence for this is lacking. This study validates whether axonal sprouting originates from the donor intact nerve by collateral sprouting with the use of a fluorescent double-labeling technique. End-to-side neurorrhaphy was performed on adult female Sprague-Dawley rats. ⋯ Double-labeling neurons, however, were seen in animals treated with end-to-side neurorrhaphy whether or not perineurotomy was performed. These results demonstrate that one parent nerve fiber can emanate another axon by collateral sprouting following end-to-side neurorrhaphy. We hypothesize that the causes of collateral sprouting might result from "switching signals" and/or "switching factors."
-
The peripheral nervous system retains a considerable capacity for regeneration. However, functional recovery rarely returns to the preinjury level no matter how accurate the nerve repair is, and the more proximal the injury the worse the recovery. ⋯ In this review article we focus on the roles in peripheral nerve regeneration of Schwann cells and of the neurotrophin family, CNTF and GDNF, and the relationship between these. Finally, we discuss what remains to be understood about the possible clinical use of neurotrophic factors.