COLLAGENASE CHEMONUCLEOLYSIS—A LONG TERM RADIOGRAPHIC STUDY IN NORMAL DOGS

Five clinically normal five year old dogs were used in this study. From a randomised table inter ver tebral discs were each injected with either collagenase or calcium chloride diluent. The surgically exposed cervical discs were injected with 50 units whereas thoracic and lumbar discs were injected under fluoroscopic guidance with 100 units of the enzyme. Postinjection radiographs revealed significant (p ≤ .05) disc space narrowing in enzyme injected discs. The cervical discs had the highest frequency of radiographic narrowing (87%) followed by the thoracic (70%) and lumbar (53%) discs. Spondylosis deformans developed at the sites of cervical enzyme injections. None of the dogs had neurologic abnormalities one year postinjection.     

CANINE CHEMONUCLEOLYSIS

Lumbar and cervical chemonucleolysis was evaluated on 16 clinically normal adult Beagle dogs in two age groups, using chymopapain at dose rates of 200 and 500 units (U). Lumbar discs injections in four discs were made transcutaneously under fluoroscopic guidance, and cervical disc injections in four discs were made after surgical exposure. Postinjection radiographs revealed a progressive narrowing of the disc spaces, first noted 24 hours after injection. Gross examination of the discs at 1-, 2-, 4-, and 8-day intervals showed a time-dependent change, with no detectable difference between the two doses and age groups. The overall rate of successful chemonucleolysis was 82.4% in the cervical discs and 78% in the lumbar discs. Clinically, the dogs showed minimal evidence of pain and no detectable postural abnormality following chemonucleolysis.