Background

Spinal cord injury (SCI) is a devastating disorder of the central nervous system that results from an acute injury.  Injury to the spinal cord results in a cascade of cellular responses, resulting in the formation of a glial scar and factors which inhibit axonal outgrowth.  To date, only methyl prednisolone has been approved (and mandated) to treat victims of spinal cord injury.  Methyl prednisolone likely enhances neuroprotection after injury; however, there is really no consensus of the efficacy of this treatment.  Other than a regimented treatment of methyl prednisolone, there is little that the neurosurgeon can do for spinal cord injured individuals, thereby leaving victims paralysed for life. 

      Several strategies are being investigated in rats to overcome SCI.  These include delivery of neuroregenerative agents, such as growth factors and netrins (Tator, Culotti/Tessier-Lavigne); delivery of neuroprotective agents, such as calpain; delivery of neutralizing molecules for myelin inhibitory molecules (David, Schwabb); delivery of cells (Raisman), including stem cells; and implantation of grafts into a transected spinal cord.  

Tissue Engineering has the potential to draw and combine almost every spinal regeneration strategy together, as all the delivered drug or cells can be easily incorporated as a matter of course. Scaffolds are the key to regeneration in the spinal cord, with many researchers predicting that oriented scaffolds are necessary in this injury site.

For the latter, grafts that have been studied are either synthetic in which cells and/or growth promoting reagents have been incorporated (Bunge, Ouedega) or peripheral nerves (Olson).  The best results have been achieved with peripheral nerve grafts, yet even these have shown limited regeneration through the graft and into the tissue.