Guided regeneration with resorbable conduits in experimental peripheral nerve injuries

Guided tissue regeneration is a new approach in the reconstructive surgery of peripheral nerves. Artificial conduits can be constructed from biodegrad able polymers. Lactic/caproic acid copolymers and polyphospazenes are bioco mpatible materials with a slow resorption rate. Conduits made from either p oly-[1-lactide-co-6-caprolatone] or poly-[bis-(ethylalanate)-phosphazene] w ere assessed for use as guides for nerve regeneration in experimental anima ls. Under general anesthesia and by using a microsurgery technique both sci atic nerves were exposed in 2 groups of 9 Wistar rats. On the right side, a 10 mm segment of the nerve was removed, and the defect was then repaired u sing a conduit. On the left side, the same defect was bridged using as an a utograft the nerve segment, which had been removed from the right sciatic n erve. Histological and electron microscopy investigations were performed af ter 30, 90 and 180 days and showed the gradual degradation of both types of conduits without any evidence of local toxicity. The regeneration of the n erve fibers in the lumen was not significantly different from that shown by the autologous grafts. Likewise, no differences were found at 180 days in the functional recovery of the nerve (evoked muscle action potential). Both conduits were found to be effective for guided nerve regeneration. Poly- [ 1-lactide-co-6-caprolactone] tubes were easier to insert, while polyphospha zene conduits allowed the use of neurite-promoting factors.