[Polymer biomaterials (polyphosphazenes) in the repair of peripheral nervous system]

Biodegradable polymers gives interesting perspectives of use in making artificial conduits for peripheral nerve reconstruction. Poliphosphazenes are materials highly biocompatible and have a controllable reabsorption rate. According to the substitutes that are introduced in the molecule, they can also be used as a framework for drug release. Conduits obtained with poli [bis(etilalanate) phosphazene] were evaluated as guides for nerve regeneration in an experimental animal model. In six Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect was then repaired using the conduit. On the controlateral limb the nerve continuity was restored using as an autograft the segment removed from the right. Control were performed at 30, 90, 180 days and consisted in histological and electron microscopy investigations. They showed the gradual degradation of the conduit without signs of local and general toxicity. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different from the one obtained with the autologous grafts. So poliphosphazene conduits may be considered effective as a guide for nerve regeneration, above all for the possibility of use the polymer as a carrier for neurite-promoting factors.