Effects of Chondroitinase ABC and Chymopapain on Spinal Motion Segment Biomechanics

STUDY DESIGN: The biomechanical effects of chondroitinase ABC and chymopapain related to spinal segmental instability were investigated using a canine model, as well by as radiologic and histologic analyses. OBJECTIVES: To evaluate the biomechanical, radiologic, and histologic affects on the lumber intervertebral disc of chondroitinase ABC compared with chymopapain. SUMMARY OF BACKGROUND DATA: No study on the biomechanical effects of chondroitinase ABC has been reported. METHODS: Forty-eight lumbar intervertebral discs in eight beagles were randomly assigned to three groups and received one of three materials: chondroitinase ABC, chymopapain, or buffered saline, using a lateral percutaneous procedure. One week after injection, the animals were killed and the lumbar spinal motion segments were removed. Spinal segmental instability after chemonucleolysis was evaluated in spinal motion segments without posterior elements. Radiologic and histologic changes were also investigated. RESULTS: Spinal segmental instability and disc space narrowing were more greater in the chymopapain group than in the chondroitinase ABC group. Destruction of nucleus and anulus proteoglycans, indicated by loss of safranin-O staining, was less intense in chondroitinase ABC-injected discs. CONCLUSIONS: Chondroitinase ABC results in less spinal segmental instability, disc space narrowing, and destruction of proteoglycans in intervertebral disc matrix than chymopapain.