Double-blind evaluation of chemonucleolysis for herniated lumbar discs. Late results.

Sixty-six patients with symptomatic herniated lumbar discs refractory to the usual conservative management were allocated at random into one of two treatment groups according to a double-blind protocol: 31 received chymopapain intradiscally (chemonucleolysis) and 35 received a placebo intradiscally. Symptoms remained significantly improved 1 year or more after injection for 55% of those treated with chymopapain and for 46% of those treated with placebo. The difference is not statistically significant. However, to discard chemonucleolysis on the basis of this one small clinical trial may be premature. Since continuing controversy has re-established a climate in which another double-blind study of chemonucleolysis is ethically feasible and scientifically desirable, we favor additional clinical trials under a tightly controlled protocol to help resolve the issue.

Double-blind evaluation of intradiscal chymopapain for herniated lumbar discs. Early results.

The authors report 66 patients with signs, symptoms, and a myelographic abnormality of herniated lumbar disc, who were not responsive to conservative treatment. The discs were injected at random with either chymopapain or a placebo. Neither patient nor surgeon knew which agent was used until after the results had been tabulated. Unless early laminectomy was necessary for intractable pain, all patients were followed for 2 months or more. There was no statistically significant difference in incidence or quality of improvement between the two groups: chymopapain was successful in 58% while placebo was successful in 49% (p = 0.15). Early results from this study indicate that most, if not all, of the putative effectiveness of chemonucleolysis probably derives from a placebo effect.