Botulinum toxin injection in vulva and vagina. Evidence from a literature systematic review

Introduction: Botulinum toxin (BoNT) administration has been proposed in the gynecologic field for pelvic, vulvar and vaginal disorders. On this regard, we aimed assessing the therapeutic effectiveness and safety of BoNT usage in the treatment of vaginal, vulvar and pelvic pain disorders. Methods: We searched for all the original articles without date restriction until 31.12.2021. We included all the original articles which administered botulinum toxin in the vulva or vagina of women suffering from vaginismus, dyspareunia, and chronic pelvic pain. Only English language studies and those performed in humans were eligible. We excluded all case reports and pilot study from the qualitative analysis, although we accurately evaluated them. 22 original studies were finally included in the systematic review. Results: Botulinum toxin injection was found to be effective in improving vulvar and vaginal dyspareunia, vaginismus, and chronic pelvic pain. No irreversible side effects were detected. Major side effects reported were transient urinary or fecal incontinence, constipation and rectal pain. The risk of bias assessment proved original articles to be of medium quality. No metanalysis could have been performed since lack of congruency in the definition of pathology and methods of botulinum toxin administration. Conclusion: Data extraction pointed out different endpoints and different methods of analysis. Studies focus on different types of participants and use various techniques and timing. According to the best evidence available, different techniques provide evidence about positive outcomes, with the need for a standardized protocol.