Study of a novel focused transcutaneous nerve stimulation device for perineal pain in women undergoing vaginal delivery: a blinded randomised sham controlled trial
Perineal pain in women undergoing vaginal delivery
At the beginning of each trial intervention session: 1. Participants will receive a briefing that some electrotherapies do not generate sensations. 2. Participants will receive TENS at a starting intensity of 10 Hz and 5 mA on the dorsum of the hand (at the middle finger metacarpal area) for the participant to appreciate the TENS sensation. The frequency applied will be increased in 10 Hz increments until sensation can be felt. The device prongs will then be applied at the same output setting to the less sensitive sub-umbilical region to demonstrate that the sensation may or may not be felt at the sub-umbilical region when the TENS device is activated to help sustain the sham process. Application method for TENS device: The patient will be placed in the left lateral position with bilateral hip flexed to 90 degrees. Ischial tuberosities are then palpated transcutaneously. The surface marking for transcutaneous access is defined as the point immediately medial to the lowest portion of the ischial tuberosity. These points are then marked with an X using an erasable marker. Device prongs will be positioned in the horizontal plane on either side of the X marks perpendicular to the skin surface at a pressure sufficient to indent 50% of the prong bulbs into the soft tissue. Two TENS devices will be used to deliver stimulation simultaneously to the right and left sides, with each site receiving 10 minutes of treatment. TENS-ON session: The TENS device output setting will be at: 1. Frequency: 10 Hz 2. Pulse width: Medium 3. Amplitude: 10 mA Control SHAM session: The TENS device output setting will be at: 1. Frequency: 0 Hz 2. Pulse width: Medium 3. Amplitude: 0 mA Randomization: Randomization will be to: 1. TENS session followed by SHAM-CONTROL session after a 4-hour gap or 2. SHAM-CONTROL session followed by TENS session after a 4-hour gap. SHAM optimization: 1. All participants will be exposed to focused TENS device prongs set at an initial frequency of 10 Hz an
1. Age ≥18 years 2. Singleton pregnancy 3. Term gestation ≥37 weeks 4. Viable pregnancy 5. Cephalic presentation 6. Vaginal delivery 7. Perineal injury requiring repair 8. Initial intervention within 2 hours of completion of repair
1. Epidural analgesia 2. Chronic pain conditions requiring ongoing analgesic therapy 3. Obstetric anal sphincter injury 4. Contraindications to TENS (e.g., cardiac pacemaker, skin lesions at electrode sites)