Bioartificial nerve graft for bridging extended nerve defects in rat sciatic nerve based on resorbable guiding filaments

A long defect (15 mm) in rat sciatic nerve was repaired with a bioartificia l nerve graft composed of a silicone tube and seven synthetic filaments of five types (polyamide, catgut, polydioxanone, and two types of polyglactin, normal and quickly-absorbed) inserted longitudinally into the tube. In all cases in which filaments were used a regenerating bridge was obtained in t he tube after three months in contrast to empty silicone tubes, in which no structure was observed. There was a 6% similar to 46% recovery of isometri c muscle contractility of the anterior tibial and gastrocnemius muscles wit h positive pinch reflex test in most cases. Myelinated axons were seen in t he regenerating tissue between the filaments but not directly in contact wi th them, and there were varying numbers of macrophages close to the filamen ts. Silicone tubes with filaments, regardless of type of filament, induced nerve tissue to regenerate and resulted in functional recovery through a 15 mm nerve gap not achieved with empty tubes. Nerve promoting factors may be applied to the filaments and the model is a valuable tool for further deve lopment of artificial nerve grafts.