Exogenous matrix precursors promote functional nerve regeneration across a 15‐mm gap within a silicone chamber in the rat

When silicone regeneration chambers are implanted empty, axonal regeneration fails if the interstump gap length is greater than 10 mm. Previous experiments using the 10‐mm gap model demonstrated that regeneration success correlated with the dimension and/or consistency of the naturally formed acellular fibrin matrix. Both spatial and temporal parameters of regeneration could be stimulated through modifications of the fibrin matrix by prefilling the chambers at the time of implantation either with phosphate‐buffered saline or plasma dialyzed against phosphate‐buffered saline. In the present experiments, similar modification of matrix formation was found to promote successful regeneration across 15‐mm and 20‐mm interstump gap lengths. In addition, prefilling 15‐mm‐gap chambers with dialyzed plasma resulted in a 3.5‐fold increase in the incidence of functional restitution detected at 8 weeks after implantation over the outcome with chambers prefilled with phosphate‐buffered saline.