Bioartificial nerve grafts based on absorbable guiding filament structures--early observations

Gaps 10 mm wide in the sciatic nerves of 64 rats were bridged by bioartificial nerve grafts consisting of a silicone tube containing seven longitudinally placed filaments made of non-absorbable, (polyamide [Ethilon]) or absorbable, material (polydioxanone [PDS], polyglactin [Vicryl], and catgut). The purpose was to study the organisation of axonal growth inside the tube along such filaments. After two and four weeks histological techniques were used to study the contents of the tube and at four weeks immunohistological techniques were used to confirm the presence of axons distal to the tube. In all experimental groups axons had traversed the tube and reached the distal segment after four weeks. Inside the tube axons were organised in multiple minifascicles in all groups, but there were no axons growing in direct contact with the filaments. We conclude that resorbable filaments placed inside a silicone tube do not disturb axonal growth across the tube.