This essay reviews the mechanisms by which motor nerves are thought to confer a regeneration benefit over traditional sensory nerve grafting techniques. Autologous sensory nerve grafting is the current standard of care for nerve injuries resulting in a nerve gap. This treatment requires the use of expendable sensory grafts to reconstruct motor defects. We have shown that pure sensory nerve grafts have an inferior regenerative capacity in comparison to nerve repair using motor and mixed grafts. These results suggest that motor nerve grafts confer an advantage to regenerating motor neurites. This phenomenon may be due to either a difference in the cellular/molecular milieu created by the presence of motor elements in the mixed and motor grafts, or it may be due to a difference in the physical architecture of the motor graft segments which is conducive to motor nerve regeneration. In order to further define this mechanism, we investigated nerve regeneration through acellularized nerve grafts of motor and sensory origin.

Our results suggest that nerve architecture plays an important role in nerve regeneration. These results question the hypothesis that cellular interactions are primarily responsible for the differences seen in motor nerve grafting compared with sensory nerve grafting. We show that nerve architecture plays a more important role in nerve regeneration than previously recognized and discuss the implications of the present findings and possible future directions for further investigations and clinical applications.