Peripheral nerve implants in the spinal cord in experimental animals

Abstract

SUIDIDary. This paper challenges the concept of 'spinal cord autotomy' as an essential process which will prevent the penetration of spinal cord fibres into a peripheral nerve implant.It proposes that mechanical distraction between the graft and the cord is the main reason why spinal cord fibres fail to traverse a graft. Clinical, neurophysiological and histological evidence is presented to show that embedding an autogenous peripheral nerve implant into a trough in the dorsal half of the cord is effective in restoring continuity in some of the long fibre tracts. Reference is made to other recent work which supports these observations. Possible methods of enhancing the number of fibres which traverse the graft are discussed and an attempt is made to anticipate the possible results of the clinical application of this technique in spinal cord injury patients.

Semi-automated counting of axon regeneration in poly(lactide co-glycolide) spinal cord bridges

“…Regenerating the injured spinal cord has been a century long endeavor with various strategies including peripheral nerve grafts, cell suspensions, and biomaterial scaffolds (Geller and Fawcett, 2002; Wilson, 1984). A key aspect in characterizing regeneration is the number of regenerating axons.…”

Encouraging Regeneration of Host Neurons:

“…Regeneration into grafts that replaced the dorsal columns of the cat spinal cord dorsal columns by a segment of the radial nerve was studied by Wilson. 28 " 30 It was suggested by the authors that partial injury of the spinal cord with preservation of the ventral half of the cord would not cause mechanical distraction and autolysis between the graft and the cord and better regeneration would occur into the graft as found in previous experiments. Although the presence of good nerve-graft junction and that of many axons traversing the nerve bridge was reported, HRP injections into the central portion of the graft resulted only in very low numbers of retrogradely labelled neurons in the spinal cord stumps and neighbouring dorsal root ganglia.…”

Peripheral nerve grafting in the spinal cord: a histological and electrophysiological study

“…Some workers have found that these grafts conduct electrical impulses (Sugar and Gerard, 1940) but others have refuted this (Brown, 1947;Barnard and Carpenter, 1950). Recent encouraging work from others and from our own laboratories (Wilson, 1984) has prompted us to investigate the function of these grafts. Previous work on spinal grafting has used the model of spinal cord transection.…”