A COMPARATIVE-STUDY OF CHEMONUCLEOLYSIS WITH COLLAGENASE AND FENESTRATION ON THE CANINE INTERVERTEBRAL DISC

The effects of treating the thoracolumbar intervertebral discs from T- 10/11 to L(2/3) in six I-year-old mongrel dogs by either lateral fenes tration, percutaneous injection of 500 IU of collagenase or percutaneo us injection of sterile saline were compared. Physical, neurological a nd radiological changes were recorded over 6 months. At the end of thi s time, the dogs were euthanized and the treated intervertebral discs harvested for histopathologic examination. In collagenase treated disc s, the nucleus was completely replaced with either hyaline or fibrocar tilage. By comparison, fenestration caused only partial removal of nuc lear material, such that the histological changes were no different th an those caused by saline injection. One dog treated with collagenase developed a transient paraparesis which was attributed to disc herniat ion during the injection procedure. It was concluded that collagenase injection is a more effective technique than fenestration at removing nuclear material from the disc.