Effects of epidural and intrathecal application of collagenase in the lumbar spine: an experimental study in rabbits.

An experimental model is described in which collagenase in different concentrations and volumes were applied epidurally or intrathecally in the rabbit lumbar spine. This made it possible to study the tissue effects in a situation similar to that of collagenase leaking from a disc or accidental epidural or intrathecal injection at chemonucleolysis. Epidurally applied collagenase, in higher concentration, caused a local thinning of the dura. This effect was reduced at lower concentrations and volumes. Intrathecally injected collagenase, even in small amounts, caused intrathecal hemorrhage and acute paraplegia in the hind limbs. Therefore, in the clinical situation, intrathecal injection of collagenase must be avoided.