The Use of Synthetic Polycaprolactone Filaments with and without Sheath to Bridge a Peripheral Nerve Defect

Abstract

Although autogenous nerve grafting is the main choice for nerve gap management, the use of synthetic nerve tube to bridge a short nerve gap is still a promising alternative for nerve repair. Polycaprolactone (PCL) filaments (30-50 in number) was used as a nerve guide in this study because of good biocompatibility, high permeability as well as low cost. Thirty Sprague-Dawley rats were divided into four groups in this study: group 1, the PCL filaments enveloped by the full sheath; group 2, the PCL filaments held together with autogenous vein grafts at both ends; group3, the PCL filaments held together with a sheath cuff at each end; group 4, the control group, 10 mm in length autogenous nerve graft. Right sciatic nerve was used as the experimental model. Soleus and tibialis anterior muscle's action potentials, muscle contractility test, and histology studies were used for result assessment after six months regeneration period. The results showed that the presence of a sheath around the filament column was the worst. The regenerating nerve fibers most grew along the outer border of the filaments column and very few in the inter-filament space. A nerve guide of PCL filaments without sheath and containing only a few filaments as the supporting frame seems to be the most advantageous for encouraging nerve regeneration. A modified advice with coiling of the PCL sheath instead of a full sheath is prospective to improve the functional outcome.