Processed porcine collagen tubulization versus conventional suturing in peripheral nerve reconstruction: An experimental study in rabbits

In peripheral nerve reconstruction, various procedures are used. One of the procedures that received the most interest in the past decade is the tubul ization technique for small nerve gaps. A disadvantage in the use of non-bi odegradable tubes is that the material often has to be removed owing to its mechanical properties. Some investigators, in exploring the use-of collage n tubes, being a natural biodegradable material, found either allogenicity or xenogenicity and immune responses that may inhibit nerve regeneration. P rocessed porcine collagen (PPC) is a new inert and biodegradable material t hat has a favorable effect on wound healing, as demonstrated by experiments on other tissues. The aim of our study was to compare the healing of nerve sutures with PPC tubes with conventional end-to-end sutures. In our experi ments, we reconstructed the saphenous nerves of 27 rabbits. In series 1 (n = 12) and 2 (n = 12), PPC tubes were slid over an end-to-end nerve suture w ithout or with a 10-mm nerve gap, respectively. In series 3 (n = 12), conve ntional suturing was performed in the collateral saphenous nerves of the an imals of series 1. Epineurial suturing was performed. Three other non-opera ted saphenous nerves served as controls. The healing was studied after 3, 6 , and 12 months in sections stained by monoclonal antibodies and by convent ional histologic staining. Morphometric analysis of the regenerating axons was done by using confocal scanning laser microscopy (CLSM). Data analysis was carried out using a software program especially developed for this purp ose, All results were evaluated statistically. Our results showed that duri ng the healing period in the distal nerve stump, the number of axons of the PPC procedure with a IO-mm gap was significantly higher than that in the p rocedure without a gap. At 12 months, the mean number of axons of all proce dures was significantly lower than in the non-operated nerve, and the mean axon diameter in all distal stumps did not differ significantly from that o f the non-operated nerve. In the distal nerve stump, the ratio of total axo n area to total fascicle area in the PPC procedure with a gap was significa ntly higher than that in the conventional suturing procedure. After 12 mont hs, there was no significant difference between the percentages of axon out growth of the PPC procedure without a gap, the conventional suturing proced ure, and the non-operated nerve (100%). The percentage of axon outgrowth in PPC with a gap was significantly higher than in the other procedures. (C) 2001 Wiley-Liss, Inc.