Botulinum Toxin Type A (BOTOX) for Refractory Myofascial Pelvic Pain

Abstract

To assess intralevator botulinum toxin type A (Botox) injections for refractory myofascial pelvic pain with short tight pelvic floor. Retrospective cohort study of all women with intralevator Botox injection (100-300 Units) from 2005 through 2010 for refractory myofascial pelvic pain. Primary outcomes were self-reported pain on palpation and symptom improvement. Secondary outcomes included postinjection complications and a second injection. Pain was assessed during digital palpation of the pelvic floor muscles using a scale of 0 to 10, with 10 being the worst possible pain. Follow-up occurred at less than 6 weeks after injection and again at 6 weeks or more. Data are presented as median (interquartile range) or proportion. Thirty-one patients met eligibility criteria; 2 patients were lostto follow-up and excluded. The median age was 55.0 years (38.0-62.0 years). Before Botox injection, the median pain score was 9.5 (8.0-10.0). Twenty-nine patients (93.5%) returned for the first follow-up visit; 79.3% reported improvement in pain, whereas 20.7% reported no improvement. The median pain with levator palpation was significantly lower than before injection (P<0.0001). Eighteen women (58.0%) had a second follow-up visit with a median pain score that remained lower than before injection (P<0.0001). Fifteen (51.7%) women elected to have a second Botox injection; the median time to the second injection was 4.0 months (3.0-7.0 months). Three (10.3%) women developed de novo urinary retention, 2 patients (6.9%) reported fecal incontinence, and 3 patients (10.3%) reported constipation and/or rectal pain; all adverse effects resolved spontaneously. Intralevator injection of Botox demonstrates effectiveness in women with refractory myofascial pelvic pain with few self-limiting adverse effects.