Optimal Frequency Used in Transcutaneous Electrical Nerve Stimulation (TENS) for Treating Pelvic Pain in Adults

Adults ages 18-90 years old who have first been given the standard of care therapy according to the AUA/EUA guidelines depending on their specific pain modality, first line treatments based on suspected etiology (for example pelvic floor physical therapy for high tone pelvic floor muscle dysfunction or amitriptyline for interstitial cystitis) without success will be defined as refractory. Participants who have plateaued on their response to current intervention strategies will be offered the TENS unit as an adjunct.

Participation will be offered by mail or in person. If by mail, the investigators will send the consent with the letter and questionnaires asking participants to call or bring the material if they would like to enroll. If the investigators speak to the subject over the phone, the investigators will discuss the study as comprehensively as if they were in the clinic. This will include explaining the concept of the TENS unit, the study itself, and clarifying any questions the participant has. Subsequently if they are interested in the study, the investigators will ask them to sign the consent and return it to us via mail or email.

Those whose pain symptomatology is above a threshold and who choose TENS therapy will be included in the study. The participants will be randomized into three groups of 25 participants each. The randomization will occur in blocks so that if the investigators need to terminate the study early there will be an equal number of participants in each group. The size of the blocks will also be kept secret for allocation concealment purposes. The randomization will be stratified by gender so that there is an equal number of participants from each gender in each group, reducing potential for gender as a confounding variable. Group 1 will be the low frequency set at 20 Hz. Group 2 will be the medium frequency set at 50 Hz. Group 3 will be the high frequency set 100 Hz. There is no sham group in this study as it has previously been found that posterior tibial TENS is effective and lasting. As such, all participants will be treated as a matter of routine medical care for pelvic pain. The investigators will use a fixed pulse width of 200 microseconds (uS), with continuous rather than biphasic stimulation. The investigators will aim to recruit 25 participants per group for a total of 75 participants.

Study Procedures

Screening Day 7/ Week 1 (in clinic or virtual): The first data points (Day 0) will take place in the clinic during the participant's routine visit or at the time of the participant's phone call seeking participation. If during a phone call seeking participation, this will be considered a study phone call, not a billable visit. The participant will fill out the VAS and GUPI. The participants will be taught how to fill out the pain assessment questionnaires (the VAS and GUPI, validated tools for measuring genitourinary pain and symptoms respectively). This can be done via paper to be brought into the office at their next checkup or via an emailed link through Qualtrics and uploaded to a spreadsheet in a protected AMC OneDrive. The baseline pain logs will be reviewed for sufficient severity of pain episodes and the participant will be randomized into the study if their pain is above the designated threshold: participants who record a pain scale of 4 or higher on any of the VAS scores or QOL score of 3 or higher on the GUPI question #9 will be eligible for the TENS study.