Transvaginal Electrical Stimulation for Myofascial Pelvic Pain

Repurposing Pelvic Floor Electrical Stimulation for the Treatment of Chronic Pelvic Pain

Myofascial Pelvic Pain (MPP) is a frequently overlooked musculoskeletal cause of chronic pelvic pain affecting 10-20% of all adult women. Despite high prevalence and societal costs, few effective treatments exist and are difficult to access due to shortages of skilled personnel. Treatments for MPP using electrical stimulation to induce muscle fatigue have proven efficacy at reducing pain, improving circulation, and promoting tissue healing, but have proven difficult to implement in gynecologic practice. The aim of this three-arm randomized study is to evaluate the utility of transvaginal electrical stimulation at a fixed frequency of 200 Hz in women with symptomatic MPP in comparison to the standard, first-line treatment with education, stretching, and low-impact exercise.

Nursing staff without prior training will be taught to deliver this high-frequency transvaginal electrical stimulation (HF-TES) treatment using the device. Responses to treatment provided by a specialist physician and licensed vocational nurse will be compared. Patients with >50% pain improvement will determine the effectiveness of HF-TES. Responses to treatment provided by a specialist physician and licensed vocational nurse will also be compared. Participants will be followed for 3 months following treatment completion.

This will be a prospective randomized trial. Sixty subjects with suspected myofascial pelvic pain will be recruited from the University of California, Los Angeles (UCLA) Center for Women's Pelvic Health. Patients will be informed of the opportunity to participate in this study by their clinician during routine office visits after a diagnosis of interstitial cystitis or bladder pain syndrome (IC/BPS) is assigned. Interested subjects will be screened for eligibility and allowed as much time as they wish to complete informed consent. MPP subjects who meet inclusion/exclusion criteria will be approached for study inclusion and randomized 2:1 to high frequency transvaginal electrical stimulation (HF-TES) vs. usual care. Baseline demographics and clinical data, including age, body mass index (BMI), comorbidities, past surgeries, and medications, including hormones, will be captured at enrollment. History will include comprehensive characterization of the pain. Standard examination will include vaginal speculum and bimanual pelvic exam, assessment of pelvic floor myofascial pain and trigger points, pelvic organ prolapse quantification (POP-Q) and vulvovaginal Q-tip testing. Urine culture and post-void residual will rule out infection and urinary retention.

After providing informed consent, subjects will complete the female Genitourinary Pain Index (fGUPI), Colorectal Functional Outcome questionnaire (COREFO), International Consultation on Incontinence Questionnaire-female Lower Urinary Tract Symptoms (ICIQ-fLUTS), and Pelvic Floor Distress Index (PFDI-20), the Vulvar and Vaginal Assessment Scales (VuAS and VAS) and Female Sexual Functional Index (FSFI) to measure visceral pelvic symptoms. The Hospital Anxiety and Depression Scale (HADS) and Short Form 12 (SF-12) will assess symptom impact on physical and mental quality of life. As no validated measures assess myofascial pelvic pain specifically, the McGill Pain Questionnaire will provide additional pain characterization. Two 24-hour voiding and bowel diaries will be completed at baseline, capturing frequency of voids and defecation, episodes of urinary or bowel urgency or incontinence, stool type, and fluid intake levels. At 1-2 weeks and 3 months (±10 days) after completing treatment, the investigators will reacquire baseline measures (including voiding and bowel diaries) as well as the Patient Global Impression of Improvement (PGI-I), satisfaction with treatment (Likert scale: 0 = not satisfied to 10 = completely satisfied) and a binary assessment of meaningful benefit from treatment (yes/no).

Participants will be randomized to receive usual care or usual care and HF-TES administered by either a specialized urogynecology provider or licensed vocational nurse (LVN) using a secure online randomization system. Minimization will balance trial group assignments according to the presence or absence of sexual dysfunction (FSFI total score <26), psychological distress (HADS total score > 10) and current hormonal medication use (yes/no). Trial group assignments will be made after initial counseling orienting the patient to usual care to avoid undue bias during the education session and training in usual care.

Treatment will be 8 weeks in duration. Therapy will be performed by a trained, registered LVN or physician, and any adverse evens, patient complains or study attrition due to perceived side effects reported immediately. There will be a post-treatment assessment, repeating pelvic floor exam, symptomatic and patient global impression of improvement surveys. A 3 month post-treatment symptomatic assessment will take place to complete determination of treatment outcomes.

Inclusion Criteria:

• Women between 18 and 65 years of age
• Pelvic pain for more than 6 months duration
• Report an average daily pain intensity score of at least 4 (on a 0 to 10 scale)
• Palpable trigger points in internal pelvic floor muscles on standardized myofascial pelvic floor exam
• Willing to refrain from new clinical treatments that may affect pain during the study period

Exclusion Criteria:

• Inability to participate in weekly clinic visits
• Prior invasive pelvic procedures for pain (e.g., prior pelvic surgery, sacroiliac joint injections, ganglion impar block, bladder instillations, sacral neuromodulation, intradetrusor or intramuscular Botox®)
• Active urinary tract infection (UTI) or vaginal infection
• Pregnancy, childbirth during the previous12 months, currently planning pregnancy
• Drug addiction
• Prior pelvic floor physical therapy
• Malignancy or other serious medical condition (e.g., poorly controlled diabetes [Glycated hemoglobin (HgA1c) > 8], neurologic or rheumatic disease)
• Diagnosed with an alternate cause of pelvic pain (e.g., interstitial cystitis, dysmenorrhea/menorrhalgia, vestibulodynia, vulvar dermatoses)
• Urinary retention
• Greater than stage 3 pelvic organ prolapse
• Indwelling vaginal devices (e.g., vaginal pessary, contraceptive ring)
• Inability to sign an informed consent, fill out questionnaires, or complete study interviews