Pilot study of botulinum toxin type A in the treatment of chronic pelvic pain associated with spasm of the levator ani muscles

Abstract

Objective: To investigate whether botulinum toxin type A (BOTOX) injected into the levator ani muscles of women with objective pelvic floor muscle spasm decreases pain symptoms and improves quality of life.

Design: A prospective cohort study.

Setting: Outpatient clinic in a tertiary referral centre, Sydney, Australia.

Sample: Twelve women, aged 18-55 years, with objective pelvic floor muscle hypertonicity and a minimum 2-year history of chronic pelvic pain were recruited.

Methods: All women completed visual analog scale pain assessments; questionnaires relating to bladder and bowel symptoms and quality of life; and specific examinations. Forty units of BOTOX at three different dilutions were given bilaterally into the puborectalis and pubococcygeus muscles under conscious sedation.

Results: Median visual analog scale scores were significantly improved for dyspareunia (80 vs 28; P=0.01) and dysmenorrhea (67 vs 28; P=0.03), with non-significant reductions in non-menstrual pelvic pain (64 vs 37) and dyschesia (47 vs 29). Pelvic floor muscles manometry showed a 37% reduction in resting pressure at week 4 and a 25% reduction was maintained at week 12 (P <0.0001). Quality of life scores (EQ-5D and SF-12) were improved from baseline at week 12, but did not reach statistical significance. Sexual activity scores were markedly improved, with a significant reduction in discomfort (4.8 vs 2.2; P=0.02) and improvement in habit (0.2 vs 1.9; P=0.03). These results were not influenced by dilution.

Conclusion: There is evidence from the present pilot study suggesting that women with pelvic floor muscles hypertonicity and pelvic pain may respond to BOTOX injections into the pelvic floor muscles. Further research into this novel treatment of chronic pelvic pain is strongly recommended.