Is Chemonucleolysis in the Cervical Spine more Dangerous than in the Lumbar Spine? (Experimental Study)
Electrically evoked compound action potentials were used to quantify the neurophysiological abnormalities caused by application of collagenase and chymopapain in rats. A branch of the sciatic nerve was stimulated with voltage impulses of constant amplitude and duration at the right external malleolus. The responses were recorded at different levels of the spine.
We used 0.1 ml of a solution of 1 ml = 1000 units collagenase (Sigma chem. comp.) and 5000 i.u. chymopapain (Woelm-pharma) for the evaluation of the neurophysiological effects. A total amount of 0.1 ml was injected into the rats spinal canal intrathrecally. The control rats were subjected to exactly the same stimulus and recording procedures but the test solution was a corresponding volume of isotonic saline.
Two hours after application there was no change in amplitude or latency of the evoked compound action potentials in the collagenase group compared to the control, although 3 of the animals developed paresis. These findings are in contrast to the increase of latency in spinal cord evoked potentials after 20 minutes in rats treated with chymopapain.
Our study indicates that collagenase acts specifically upon central nerve tissue whereas chymopapain causes nonspecific damage of central and peripheral nerve structures. We conclude that chemonucleolysis in the cervical spine by these 2 enzymes is of higher risk because here central nerve structures are close to the site of injection. This is in contrast to the lumbar spine.
Further investigation should focus on long-term follow up and on the role of the motorneuron and the ventral roots in the development of neurological complications after intrathecal injections of collagenase and chymopapain.
KeywordsLumbar Spine Cervical Spine Intrathecal Injection Ventral Root Evoke Compound Action Potential
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- 1.Brown MD (1983) Intradiscal therapy: Chymopapain or collagenase. Year Book Medical Publishers, ChicagoGoogle Scholar
- 7.Wehling P, Pak MA, Cleveland S, Schulitz KP The influence on spinal cord evoked potentials of chymopopain appüed to the rat lumbar spinal canal. Spine, accepted for pubhcationGoogle Scholar
- 8.Wiltse LL, Widell EH, Hansen AY (1975) Chymopapain chemonucleolysis in lumbar disc disease. YAM A 231: 474–479Google Scholar