The artificial nerve graft: a comparison of blended elastomer-hydrogel with polyglycolic acid conduits.

A study was undertaken to compare the regeneration of rat peroneal nerves across a 0.5-cm gap repaired with either a permanent, porous or a resorbable, non-porous artificial nerve graft. The resorbable, impermeable artificial nerve graft was a synthetic passive conduit made from polyglycolic acid (PGA). The permanent, porous artificial nerve graft conduit was manufactured from a hydrophilic elastomeric biopolymer (HEB), and four variations were tested. Qualitative histology on short-term animals revealed similar inflammatory reactions to HEB and PGA. Axonal regeneration was evaluated in longer-term animals after three, four, and six months by qualitative and quantitative histology. Qualitative histology on longer-term animals demonstrated both artificial nerve grafts to be anti-immunogenic. All PGA-artificial nerve graft repairs among three-, four-, and six-month rats contained myelinated axons, as did all HEB-1 repairs. However, three other HEB-graft varieties accounted for a 25 percent failed regeneration rate. Quantitative histologic comparison of repair-site cross-sections in viable PGA and HEB matched pairs demonstrated statistically equivalent myelinated axon counts but larger average myelinated fiber diameters in HEB repairs, with p = .001.

Sutureless nerve repair at the fascicular level using a nerve coupler.

Peripheral nerves are transected in many traumatic injuries of the extremities. Satisfactory functional regeneration of such nerves often fails to occur after repair with sutures. Possible reasons for these failures include poor alignment of nerves or fascicles, intrusion of scar tissue into the nerve junction, and outgrowth of nerve tissue from the repair site. This animal study describes an experimental method of sutureless, monofascicular peripheral nerve repair using a resorbable nerve coupler in the rat model. The first version of this coupler shows approximately equal performance to suture repair. Histology and electrophysiology assessments after regeneration showed that the polyglycolic acid (PGA) tube repairs were functionally equal to monofascicular suture junctions as well as being quicker and simpler to perform. Modified coupler designs based on this and other work show greater promise. Collateral studies are using similar versions of the nerve coupler as a vehicle for the insertion of chemical and neuro-electronic factors that may enhance nerve regeneration.