Study design: Fifty-six patients with lumbar disc herniation who had participated in a double-blind study comparing chymopapain with saline were invited to undergo a magnetic resonance imaging assessment of the lumbosacral spine more than 10 years later.
Objective: The aim of this study was to assess the long-term morphologic changes after treatment of disc herniation by chemonucleolysis and laminectomy and to compare these findings with the natural history of the disorder.
Summary of background data: There is little information on the effects of different treatment methods for lumbar disc herniation on the long-term morphologic changes in the disc.
Methods: Of the original 56 patients, 39 were entered into the study: 12 had been treated by saline injection alone, 14 by chemonucleolysis alone, and 13 had subsequently required laminectomy for a failed intradiscal injection. Each sequence of magnetic resonance images was examined by a radiologist who was unaware of the treatment given. The signal strength was assessed on T2-weighted images in the sagittal plane and disc morphology on T1- and T2-weighted sagittal and T1-weighted axial images.
Results: The signal of the treated disc was absent in all cases in each group. Thirty-seven percent of patients were found to have a persistent herniated disc and the incidence was similar in all three treatment groups. The presence or absence of herniation at 10 years had no significant bearing on a successful outcome.
Conclusion: The findings of this study indicate that long-term improvement of a patient's symptoms after treatment of disc herniation may occur with or without resolution of the hernia. This and the similar morphologic findings in the different groups is consistent with the 10-year clinical results after the treatment of disc herniation reported by Weber.