Botulinum Toxin A Injections Into Pelvic Floor Muscles Under Electromyographic Guidance for Women With Refractory High-Tone Pelvic Floor Dysfunction: A 6-Month Prospective Pilot Study

Objectives High-tone pelvic floor dysfunction (HTPFD) is a debilitating chronic pain disorder for many women with significant impact on their quality of life (QoL). Our objective was to determine the efficacy of electromyography-guided onabotulinumtoxinA (Botox; Allergan, Irvine, Calif) injections in treating patient’s perception of pelvic pain and improving QoL measurement scores. Methods This is a prospective pilot open-label study of women with chronic pelvic pain and HTPFD who have failed conventional therapy between January 2011 and August 2013. Botox injections (up to 300 U) were done using needle electromyography guidance, from a transperineal approach, to localize spastic pelvic floor muscles (PFMs). Data were collected at baseline, 4, 8, 12, and 24 weeks after injections. This included demographics; Visual Analog Scale (VAS) scores for pain and dyspareunia; validated questionnaires for symptoms, QoL, and sexual function; Global Response Assessment scale for pelvic pain; digital examination of PFM for tone and tenderness; and vaginal manometry. Side effects were also recorded. Results Out of 28 women who enrolled in the study, 21 completed the 6-month follow-up and qualified for analysis. The mean (SD) age was 35.1 (9.4) years (range, 22–50 years), and the mean (SD) body mass index was 25 (4.4). Comorbidities included interstitial cystitis/bladder pain syndrome (42.9%) and vulvodynia (66.7%). Overall, 61.9% of subjects reported improvement on Global Response Assessment at 4 weeks and 80.9% at 8, 12, and 24 weeks post injection, compared with baseline. Of the subjects who were sexually active at baseline, 58.8% (10/17), 68.8% (11/16), 80% (12/15), and 83.3% (15/18) reported less dyspareunia at 4, 8, 12, and 24 weeks, respectively. Dyspareunia Visual Analog Scale score significantly improved at weeks 12 (5.6, P = 0.011) and 24 (5.4, P = 0.004) compared with baseline (7.8). Two of the 4 patients who avoided sexual activity at baseline secondary to dyspareunia resumed and tolerated intercourse after Botox. Sexual dysfunction as measured by the Female Sexual Distress Scale significantly improved at 8 weeks (27.6, P = 0.005), 12 weeks (27.9, P = 0.006), and 24 weeks (22.6, P < 0.001) compared with baseline (34.5). The Short-Form 12 Health Survey (SF-12) showed improved QoL in the physical composite score at all post injections visits (42.9, 44, 43.1, and 45.5 vs 40 at baseline; P < 0.05), and in the mental composite score at both 12 and 24 weeks (44.3 and 47.8 vs 38.5, P = 0.012). Vaginal manometry demonstrated significant decrease in resting pressures and in maximum contraction pressures at all follow-up visits (P < 0.05). Digital assessment of PFM (on a scale from 0 to 4) showed decreased tenderness on all visits (mean of 1.9, 1.7, 1.8, 1.9; P < 0.001) compared with baseline (2.8). Reported postinjection adverse effects included worsening of the following preexisting conditions: constipation (28.6%), stress urinary incontinence (4.8%), fecal incontinence (4.8%), and new onset stress urinary incontinence (4.8%). Conclusions Electromyography-guided Botox injection into PFM could be beneficial for women with refractory HTPFD who have failed conservative therapy.