Nucleolysis and diskography--an experimental study on interaction of chymopapain and contrast medium

A test was carried out on 11 young, full sized mongrels to determine whether there is an interaction between chymopapain and the contrast agents iotrolan and iopamidol. A total of 75 intervertebral disks were punctured: nucleolysis alone was performed on 20, diskography with iotrolan and subsequent nucleolysis on 20, and diskography with iopamidol and subsequent nucleolysis on 10. Diskography alone was performed 10 times with iotrolan and 5 times with iopamidol. Aqua dest. was given intradiskally 5 times, and puncture was carried out 5 times without the administration of any substance. Following puncture, x-rays of the lumbar vertebral column were taken laterally: daily for the first 10 days, then weekly. Disk space narrowing typical of nucleolysis with chymopapain was found among the disks that were nucleolyzed only to the same extent as among those that had undergone diskography previously. There was no evidence of narrowing of the other disk spaces which had been punctured but not treated with chymopapain. On some of the dogs, CT and MRI examinations were carried out. The CTs showed a homogenous hypodensity in all of the disks, in which chymopapain had been injected. The MRI revealed a signal loss in all of the nucleolyzed disks. The results of short and long term follow up demonstrate that inhibition of chymopapain by iotrolan or iopamidol is not to be expected and therefore diskography prior to chemonucleolysis can be performed without danger of enzyme inactivation.