Objectives: A previous randomized controlled trial from 1991 to 1993 comparing excision of endometriosis with sham surgery demonstrated no difference in reported pain after blinding between the excision and sham groups for one year. Overall, when both groups were considered, there was a significant reduction in pain one year postoperatively. This trial was done to determine the predictors of subsequent surgery.
Methods: The time to repeat surgery was the outcome of interest as a marker for significant pain. Survival analysis and log rank tests were performed to determine if the time to repeat surgery differed by group or by age, parity, original level of pain pre-operatively and stage of the disease.
Results: Only the reported measurement of pain prior to the initial trial was a significant covariate in the overall prediction of repeat surgery among all subjects. The overall repeat surgical operation rate was 48.3% in the sham surgery group and 51.7% in the excision group. The estimated relative risk for repeat surgery (excision vs. sham) was 1.42 (95% confidence intervals 0.539- 3.75).
Conclusion: Pain experience preoperatively was found to be an important predictor of subsequent surgical need. In this study, age, stage of disease, and excision of endometriosis were not associated with improvement in pain as measured by the time to repeat surgery.