Botulinum toxin A (Botox) injection into muscles of pelvic floor as a treatment for persistent pelvic pain secondary to pelvic floor muscular spasm: A pilot study.

[BACKGROUND] Persistent pelvic pain (PPP) remains an important cause of morbidity. Pelvic floor muscle spasm is an important contributor to PPP.

[AIMS] The study's primary aim was to assess if botulinum toxin (BoNT) injection to pelvic floor muscles altered pain scores or quality of life (QoL) at six, 12 and 26 weeks. Secondary aims included investigating the impact of BoNT on opiate usage, examining the role of pain catastrophising, and assessing for complications.

[MATERIALS AND METHODS] A single-centre prospective cohort study enrolled 21 patients with PPP who had failed physiotherapy techniques. Each participant underwent BoNT injection to muscles of the pelvic floor and pudendal nerve block. Questionnaires and digital vaginal examinations were conducted at baseline, six, 12 and 26 weeks. Pain score quantification used visual analogue scales (VAS) and numerical rating scales (NRS). Other outcome assessments included The World Health Organization Quality of Life instrument (WHOQoL-BREF), Pain Catastrophising Scale (PCS), and modified Australian Pelvic Floor Questionnaire (APFQ). ACTRN12620000067976.

[RESULTS] Following BoNT injection, median VAS scores decreased for all domains at six and 12 weeks, with VAS for dyspareunia significant at six weeks (P = 0.026). Scores returned to baseline by 26 weeks. Opiate usage was significantly less following BoNT injection, with a percentage reduction of 23.8% (95% CI -48.3 to 0.7, P = 0.06). Sexual function improved significantly (P < 0.01), and at six months, four previously apareunic participants reported successful penetrative vaginal intercourse. Health-related QoL and PCS demonstrated sustained improvement (P = 0.02-0.05). NRS for muscle tenderness decreased for all assessed muscle groups (P < 0.001).

[CONCLUSIONS] BoNT requires further assessment as a treatment modality for select women with PPP.