Electromyography-guided botulinum toxin injections in provoked vestibulodynia: a randomized double-blind placebo-controlled clinical trial.

[BACKGROUND] Provoked vestibulodynia is a prevalent and complex disease with a major effect on women's quality of life. This condition is often associated with abnormal reflexes and muscle hypertonicity. Local injections of Onabotulinum toxin A guided by electromyography have been reported as a promising therapeutic possibility, although randomized controlled trials are lacking.

[OBJECTIVE] To assess the efficacy of electromyography-guided Onabotulinum toxin A in provoked vestibulodynia. The primary endpoint was a modification of the pain visual analog scale after treatment.

[STUDY DESIGN] This randomized, double-blind trial compared electromyography-guided injections of Onabotulinum toxin A (50 units) vs placebo into the superficial perineal muscles. Patients were randomized and received electromyography-guided injections of either saline or Onabotulinum toxin A (50 U on each side in superficial perineal muscles). Data on pain (assessed using a visual analog scale), quality of life (measured by the Dermatology Life Quality Index), and quality of sex life (assessed using the Female Sexual Function Index) were collected before treatment and 3 and 6 months after injection.

[RESULTS] Sixty patients were randomized. The mean±standard deviation age was 26.1±0.8 years. After 3 months, the pain visual analog scale decreased in the treated group to 5.04±0.61 vs 7.37±0.45 in the placebo group (P=.008). The Dermatology Life Quality Index differed in the treatment and placebo groups at 3 and 6 months (P<.01 and P=.03, respectively). In the Female Sexual Function Index evaluation, the scores of the items "sexual satisfaction" and "sexual desire" were higher in the treated group than in the placebo group (P=.05 and .01, respectively).

[CONCLUSION] Onabotulinum toxin A injections were effective on the pain, quality of life, and sexual functions of the patients. We suggest that muscular dysfunction is a key element of vestibulodynia pain. Electromyography-guided Onabotulinum toxin A injections were associated with improvement of symptoms in provoked vestibulodynia.