The effect of spondylosis on the outcome of chemonucleolysis

In an attempt to understand the relation between the outcome of chemonucleolysis treatment of lumbar discs and the presence of spondylosis (degenerative process) of the lumbar spine, 40 cases of disc herniation with subsequent intradiscal chymopapain injection (chemonucleolysis) were reviewed. Thirty-eight patients had plain radiographs, 25 had myelography, 28 had computed tomography (CT), and 15 had both myelography and CT. A review of these examinations revealed that 24 patients had minimal or mild spondylosis (group 1) and 13 patients had moderate spondylosis (group 2). Only one patient had a severe spondylosis (group 3). Chemonucleolysis failed in 8/24 (33%) patients from the first group and 2/13 (15%) cases from the second group. Therefore, the presence or absence of even moderate spondylosis did not affect the treatment success rate. A review of the 11 failed cases revealed spinal canal stenosis in three cases and a large disc herniation in two (one case with a myelographic block). Another case had a sequestered disc fragment. In two further cases, the disc herniation was far lateral with complete occlusion of the lateral foramen; another case exhibited severe degenerative changes of facet joints. In two other cases, treatment failure could not be explained by any radiographic finding. Of three patients with large disc herniation, only one responded successfully to intradiscal injection of chymopapain. Chemonucleolysis, however, failed in the only patient in the third group who had severe spondylosis of the facet joint.