PURPOSE
The use of Onabotulinum Toxin A (BTX) to chemically denervate the testis has been studied as a minimally invasive therapy to treat chronic scrotal pain (CSP). To date no randomized control trials on BTX use for CSP management have been reported.
MATERIALS AND METHODS
In this double-blinded randomized control trial, men with CSP who had at least temporary pain relief following a cord block with local anaesthetic (LA) were randomly assigned to blocks using LA alone vs. LA plus 200IU BTX. Standardized assessments of pain levels (visual analog scores: VAS), disease impact, quality of life and mood was performed at 1, 2, 3, 4, 12 and 18 weeks post-injection. The primary outcome was the change in VAS at one month. After completion of the study, men in the control group were given the option to receive BTX as part of an open-label trial.
RESULTS
Of 64 men (mean age 45.9±11 and duration of pain 5.7 ±5.7 years), 32 received LA/BTX and 32 LA alone. There was no statistically significant difference in any measured outcome comparing BTX to controls. 9/13 (69.2%) men in the open label trial demonstrated an improvement of their VAS score (mean group VAS score 6.1 +/- 1.66 to 4.5 +/- 2.36, p=0.022, student's t-test) with 6/9 (66.7%) having persistent pain reduction at 3 months.
CONCLUSIONS
This randomized, double-blinded, controlled trial does not show superiority of BTX/LA over LA alone for pain control for men with CSP. Interestingly, there was significant pain improvement noted in our open label BTX trial, suggesting a potential placebo effect.