COLLAGENASE CHEMONUCLEOLYSIS - A LONG-TERM RADIOGRAPHIC STUDY IN NORMAL DOGS

Five clinically normal rive year old dogs were used in this study. Fro m a randomised table intervertebral discs were each injected with eith er collagenase or calcium chloride diluent. The surgically exposed cer vical discs were injected with 50 units whereas thoracic and lumbar di scs were injected under fluoroscopic guidance with 100 units of the en zyme. Postinjection radiographs revealed significant (p less-than-or-e qual-to .05) disc space narrowing in enzyme injected discs. The cervic al discs had the highest frequency of radiographic narrowing (87%) fol lowed by the thoracic (70%) and lumbar (53%) discs. Spondylosis deform ans developed at the sites of cervical enzyme injections. None of the dogs had neurologic abnormalities one year postinjection.