A resorbable nerve conduit as an alternative to nerve autograft in nerve gap repair

Poly-3-hydroxybutyrate (PHB) occurs within bacterial cytoplasm as granules and is available as bioabsorbable sheets. Previously the advantage of PHB i n primary repair has been investigated while in this study the same materia l has been used to bridge an irreducible gap. The aim was to assess the lev el of regeneration in PHB conduits compared to nerve autografts. The rat sciatic nerve was exposed, a 10 mm nerve segment was resected and b ridged with either an autologous nerve graft or a PHB conduit. The grafted segments were harvested up to 30 days. Immunohistochemical staining was per formed and computerised quantification of penetration distance and volume o f axonal regeneration was estimated by protein gene product (PGP) immunosta ining and calcitonin gene-related peptide (CGRP) positive fibres. Penetrati on and proliferation density of Schwann cells into the conduit was measured by quantifying S-100 staining. The inflammatory response was quantified wi th ED-1 staining for macrophages. Antibodies to vWf provided an assessment of angiogenesis and capillary infiltration. Percentage immunostaining for PGP in autograft and PHB groups showed a prog ressive increase up to 30 days with a significant linear trend with time an d an increase in the Volume of axonal regeneration. A similar pattern of pr ogressive increase with time was observed with CGRP immunostaining for both groups and with S-100 in the PHB group. Good angiogenesis was present at t he nerve ends and through the walls of the conduit. The results demonstrate good nerve regeneration in PHB conduits in comparison with nerve grafts; ( C) 1999 The British Association of Plastic Surgeons.