The “bioartificial living nerve graft”.

Abstract

Nerve tubes seeded with cultured Schwann cells have become a promising alternative to nerve autografts. However, the functional results of these bioartificial cellular grafts remain to be improved. To imitate the three-dimensional structure of peripheral nerves, we designed a Schwann cell-seeded intrinsic framework within a semipermeable biodegradable collagen nerve tube (Integra). In 90 rats a 25 mm gap was created at the sciatic nerve of the right lower limb. In group I, the gap was treated using the "bioartificial nerve graft". In group II, the tube filled with non-seeded filaments was implanted in order to evaluate the influence of the Schwann cells on regeneration. In group III, the gap was bridged using an autologous nerve graft. For evaluation clinical testing, gait analysis, electrophysiological conduction testing, tibialis anterior muscle weight recording and axon counts from the distal nerve stump were used. There was a significant difference between the "bioartificial nerve graft" (group I) and the non-seeded bioartificial nerve graft (group II) indicating the importance of the living Schwann cells. Comparing the results of the "bioartificial nerve graft" (group I) with the autologous nerve grafts (group III), there was a significant difference in all the examinations indicating a still slower regeneration in the artificial graft. We conclude that the unique three-dimensional net allowed the settlement of Schwann cells onto the biodegradable filaments, which can be used as "artificial Bünger bands". With further refinements of the "artificial Bünger bands" and Schwann cell cultures there should be improved functional and histological results in the "bioartificial nerve graft" group.