The botulinum toxin (BoNT) injection when  administered into pelvic floor muscles was found to be safe and tolerable as an out-patient method in women with chronic pelvic pain/ vaginismus/ vulvar pain disorders (CPP/V/VPD), demonstrated a recent study issued in 'International Urogynecology Journal'.

BoNT offers pain relief, particularly in a muscle spasm. Karp BI and other investigators conducted the study to describe and include the method of use of BoNT treatment in women with CPP.

The database search was performed using the terms "pelvic pain," "botulinum toxin and "vaginismus." The "vaginismus/vulvar pain disorders" (V/VPD) comprised of reports on vaginismus /vulvodynia/ vestibulodynia (considered if pelvic floor muscles were injected). The study investigators evaluated the type of report, muscle selection, condition, dose/dilution, guidance process, toxin serotype/brand and anesthesia. For particular analyses, the publications from the same writers without different information were consolidated. 

Although many reports lacked complete information, 38 reports had analyzable information. Most of the reports were open-label prospective, 4 reports were technical, 1 report was a placebo-controlled study evaluating efficacy and 1 report was a randomized comparison of doses. Transvaginal, transperineal or transgluteal modes were used to address pelvic floor muscles. BoNT brand/dose/dilution varied throughout. Electromyography, fluoroscopy/CT scanning, anatomical landmarks and electrical stimulation with/without ultrasound were the muscle localization techniques included in the study. The papers examining analgesia used general anesthesia, conscious sedation with/without topical/local anesthesia, topical/local agent alone or pudendal block before or after the injection.

Cumulative improvement was noted in 71-100% of patients with V/VPD and 58-100% of patients with CPP. Serious adverse events example transient fecal incontinence/constipation, urinary incontinence/retention was more frequently observed with the higher doses.