Poly-3-hydroxybutyrate (PHB): a resorbable conduit for long-gap repair in peripheral nerves

The repair of peripheral nerve injuries with an autologous nerve graft is still the treatment of choice, although it is widely recognised that the method is associated with donor-site morbidity and a suboptimal functional outcome. An alternative approach is to use a nerve conduit to provide a guidance channel for the regenerating nerve. This study investigates the potential of poly-3-hydroxybutyrate (PHB) nerve conduits to bridge long nerve gaps (up to 4 cm) in a rabbit common-peroneal-nerve injury model. Regeneration was assessed up to 63 days postoperatively, and compared with that achieved using nerve autografts. By 42 days, regenerating axons had bridged nerve gaps of all lengths in groups with nerve autografts and in those with PHB conduits. The regeneration distance increased with time but did not vary with gap length (P≤0.009, 14 versus 21 days, PHB tube 2 cm, 3 cm and 4 cm, Mann-Whitney U-test). At 42 days, the area of immunostained regenerating fibres in the PHB group was greater than that in the nerve autograft group (P<0.001, PHB versus autograft, 21 and 42 days, three-way analysis of variance (ANOVA). These results suggest that PHB conduits support peripheral nerve regeneration up to 63 days, and that they are suitable for long-gap nerve injury repair.