ATTEMPTED EXPERIMENTAL MODIFICATION OF THE POSTLAMINECTOMY MEMBRANE BY LOCAL INSTILLATION OF RECOMBINANT TISSUE-PLASMINOGEN ACTIVATOR GEL

A prospective, randomized, blinded trail involving 25 adult mongrel do gs was performed to evaluate whether placement of a fat graft or local instillation of recombinant tissue-plasminogen activator gel (rt-PA) could modify the development of a postlaminectomy membrane. One compon ent of the study involved the performance of a lumbar laminectomy and placement of gel re-PA, free fat, or no tissue placement over the expo sed dura mater. Three months later the animals were killed and section s of spine were removed en bloc, decalcified, and examined histologica lly. No significant differences were found in the degree of cellular f ibrosis or heavy collagen production. A similar laminectomy at another lumbar level was also followed by gel rt-PA, free fat, or no tissue p lacement. Three months after surgery, surgery was performed again at t his level immediately before death. There were no differences in the a dhesiveness of the laminectomy membrane to dura mater or roots. It was concluded that the local instillation of gel rt-PA after laminectomy did not inhibit scar formation or scar adherence to the dura matter.