Chemonucleolysis versus surgery in lumbar disc herniations: correlation of the results to preoperative clinical pattern and size of the herniation.

A prospective study was carried out on the results of chemonucleolysis or surgery in 156 patients who had lumbar disc herniations. All patients were considered as potentially good candidates for chemonucleolysis. Seventy-two received a chymopapain injection and 84 underwent surgery. Based on computerized tomography (CT) scan and/or myelography the herniations were distinguished as small, medium, and large. Also distinguished were three types of preoperative clinical patterns, Type A, Type B and Type C, corresponding to slight, moderate, and severe nerve root compression, respectively. Follow-up evaluations were made 1 month, 3 months, and an average of 2.8 years after treatment. The patients with a small disc herniation, who underwent chemonucleolysis, did slightly better as a group than those treated surgically. At 1 month, the proportions of satisfactory results were 75% in the chemonucleolysis group and 62% in the surgery series. At final follow-up, the proportions were 84% and 82%, respectively, but the ratio of excellent-to-good results was higher in the chemonucleolysis group. In the latter, most patients with satisfactory outcomes had a Type A or Type B clinical pattern. In medium-size herniations the results of surgery were slightly better than those of chemonucleolysis. At 1 month, 55% of patients in the chemonucleolysis group had satisfactory results compared with 74% of those in the surgery series; at final follow-up the proportions were, respectively, 76% and 86%. In the chemonucleolysis group most satisfactory outcomes were found in patients with a Type A or Type B clinical pattern. The results of chemonucleolysis in patients who had large herniations were significantly inferior to those of surgery: at final follow-up the results were satisfactory in 50% of patients in the chemonucleolysis group and 89% of those in the surgery series. Chemonucleolysis appears to be the treatment of choice in most patients with small disc herniations and an effective alternative to surgery in most patients with medium-size herniations when the preoperative clinical pattern indicates a slight or moderate nerve root compression. In all large herniations and in small- or medium-size herniations causing a severe nerve root impingement, surgery should be preferred to chemonucleolysis.