2. Materials and Methods
vulvovaginal infection, VBD, dyspareunia, Vulvovaginal Disease vulvodynia, pain, Pelvic floor muscle
GENITAL BLEEDING, CONTRACTIONS, DYSPAREUNIA, SECONDARY, VAGINA
This was a randomized, single-blind, controlled trial performed between January 2019 and December 2019. Institutional Review Board approval for the study was obtained and registered at The exclusion criteria were an active vulvovaginal infection at the time of their gynecological examination, genital bleeding of unknown origin, a cardiac pacemaker, or pregnancy. Patients enrolled in the trial signed an informed consent form and were randomly and blindly assigned to one of two groups with different parameter combinations of TENS therapy in a self-administered domiciliary protocol. Before randomization, patients were asked to stop any topical, systemic, or physical therapy at least 30 days before starting TENS therapy. Women with VBD completed questionnaires and underwent a gynecological examination, including a vulvo- and colposcopy. The International Society for the Study of Vulvovaginal Disease vulvodynia questionnaire was used in this study [All subjects underwent vaginal surface electromyography (EMG). Vaginal EMG measurements were taken at rest and during several exercises of the pelvic floor, through an EMG device with a vaginal sensor (Myotonus plus©-London-UK). Pelvic floor muscle (PFM) activity at rest was measured as the mean muscle tone value at rest after six maximum contractions separated by a rest period of at least 12 s, while the PFM peak activity was calculated as the mean of six maximum voluntary contractions separated by a rest period of at least 12 s. The assessments also included the PFM strength obtained by subtracting the maximal value from the resting values [The primary efficacy endpoint for this study included the mean change from baseline to 60 and 120 days of pain and dyspareunia. The secondary endpoints were variations in the vestibular cotton swab sensitivity and vaginal EMG measurements.A dual-channel portable TENS unit (EVA©; Sirval, Milan, Italy) was used. The stimulation was delivered through a plastic vaginal probe connected to the device (Periprobe VAG2ST; Sirval, Milano, Italy) that was 20 mm in diameter and 110 mm in length with two gold metallic transversal rings as electrodes. The tube was inserted 20 mm into the vagina. The participants were randomized into two groups with different electrical stimulation treatment regimens. Two customized programs were set for each group according to our previous studies [The electric parameters used in both treatments were:Group 1: 15 min of 100 Hz frequency, a pulse width of 50 µs, and time on:off 20:10 s (first program) followed by 15 min of 5 Hz frequency, a pulse width of 100 µs, and time on:off 20:10 s (second program).Group 2: 15 min of 60 Hz frequency, a pulse width of 50 µs, and time on:off 20:10 s (first program) followed by 15 min of 5 Hz frequency, a pulse width of 200 µs, and time on:off 20:10 s (second program).Each patient underwent two to three assessments designed to familiarize them with the use of TENS while allowing the therapist to check if the patient was using the device properly. In the TENS treatment protocol, the pulse was increased rapidly until the patient reported any sensation under the electrodes. The intensity was then increased slowly until this sensation reached a level described as the maximum tolerable sensation without experiencing pain. After completing the trial, the patient obtained their TENS unit after verbal and written instructions, with a recommendation to perform home treatment three times per week.Randomization was generated by a computer program, and the concealed allocation was achieved by varying the number of self-adhesive labels attached to the TENS unit according to the information provided in the envelope sent to the company representative. The envelope sent to the clinic contained information on which of the number-coded units should be handed out to the participants of the first and second groups. The data were all blinded from the commencement of the analysis until after the completion of study protocols.The sample size was calculated based on averages and standard deviations of a mean pain reduction of 3.5 points based on the results of available studies regarding the use of TENS in a woman with VBD [