Alternative techniques for peripheral nerve repair: conduits and end-to-side neurorrhaphy.

Nowadays new techniques may help the surgeon in difficult cases of nerve tissue loss: when a gap is produced in a mixed nerve, the use of conduits can be an alternative to nerve grafts, which still represent the "gold standard" for this kind of lesions. We have applied biologic conduits (muscle inside a vein) in more than 40 cases since 1993 with 85% of good functional results for both sensory and mixed nerves up to 5 cm. The advantages of this technique are: (1) all graft material is easily withdrawn in the lesion area and thus is not necessary to perform any new incision; (2) the possibility of reconstructing nerve gaps up to 5 cm avoids secondary damage created by the withdrawal of healthy nerves; (3) the possibility for spontaneous orientation of regenerating nerve fibers is offered as fibers are allowed to search for their final target (chemiotropism). Furthermore, when the tissue loss is important or the proximal nerve stump is not available, so jeopardizing the possibility of recovery with traditional reconstruction, the use of end-to-side neurorrhaphy has been described to solve the problem. However the use of end-to-side neurorrhaphy in the clinical setting for motor recovery remains controversial. In our experience we had satisfying results only in 20% of cases and thus motor reconstruction in the absence of an available proximal nerve may be best handled by nerve to nerve transfers. By contrast we had good results in sensory nerve reconstruction (especially digital nerves) by end-to-side coaptation.