Eight- to 13-year follow-up evaluation of chemonucleolysis patients

739 patients treated eight to 13 years previously with chymopapain injection are evaluated by questionnaire. The results were 76% satisfactory and 24% unsatisfactory. When those with prior surgery, midline discs, and spondylolisthesis were eliminated, there is a satisfactory result in 82% with 60% excellent, reinforcing the importance of patient selection for the procedure. Thirty-one percent of patients had preoperative myelograms, and all had discograms and were done under general anesthesia with the single needle technique. Of the excellent and good results, 50% had a two-level injection, while one-level injections produced only 23% and 20%, respectively. Results in midline discs are comparable to lateral displacement and the 13 patients with spondylolisthesis had 85% satisfactory outcome. In ten patients younger than 19 years of age, only one was a failure. Sixteen percent of patients had prior surgery and they reported a successful outcome of injection in 55%. Of the 179 unsatisfactory results in the series, subsequent treatment reduced the rate of failed end results to 14%. The study verifies the persistence of early satisfactory results and shows no late complications such as symptomatic iatrogenic spinal stenosis.