Neural regeneration along longitudinal polyglactin sutures across short and extended defects in the rat sciatic nerve

Object. The authors have previously shown that longitudinal sutures without artificial tube support regeneration across a 7-mm gap in the rat sciatic nerve. In the present study, the authors, compared this new approach with t he use of autologous nerve grafts across short defects and examined whether the approach could be used to support regeneration across extended gaps an d whether the interposition of a short nerve segment (the stepping-stone pr ocedure) was applicable in this model. Methods. Longitudinal sutures were used to bridge 7- and 15-mm gaps in the rat sciatic nerve. Contralateral comparisons were made to nerve autografts in the 7-mm group and to sutures plus a short interposed nerve segment in t he 15-mm group. Regeneration was evaluated at 2, 4, and 12 weeks by using i mmunocytochemical analysis for Schwann cells, neurofilament protein, and ma crophages and at 12 weeks also by using histological examination, including morphometry in the distal tibial trunk and tetanic force measurements in t he gastrocnemius muscle. Conclusions. The authors found that the results of regeneration after repai r with longitudinal polyglactin sutures across short defects were not signi ficantly different from those produced by the use of autologous nerve graft s. Regeneration, although poor, occurred along sutures across extended gaps and was significantly enhanced by an interposed nerve segment acting as a Schwann cell resource in this model.