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Refractory Visceral Pelvic PainGNS-PAINNCT07884305

Transcutaneous Genital Nerves Stimulation for the Treatment of Refractory Chronic Pelvic and Genital Pain in Women.

A study testing Transcutaneous Genital Nerves Stimulation in people with Refractory Visceral Pelvic Pain and Refractory Genital Pain, run by Prof. Dr. med. Marc Possover at 1 site in Switzerland.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

This study will explore whether non-invasive electrical stimulation can reduce chronic genital pain, deep pelvic pain, or both in adult women whose symptoms have persisted for at least six months despite conventional treatment. Approximately 50 women will participate at several clinical centers. Read more about this study

Who is it for?
Ages 18 years and older, women only
What is being tested?
Transcutaneous Genital Nerves Stimulation
Type of treatment
Medical device
Could I receive a placebo?
No, everyone receives an active treatment
How many people
50 participants
Where
1 siteSwitzerland
Study dates
1 Dec 2026to 1 Aug 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • Women only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • All of the following must be met:
  • Female sex, age ≥18 years
  • Chronic pelvic pain persisting ≥6 months
  • Average baseline NRS ≥4/10 in the prospectively designated index pain domain
  • Persistent genital pain and/or deep visceral pelvic pain, including a mixed phenotype, with a clinically meaningful average NRS ≥4/10 in at least one domain during baseline
  • Pain refractory to appropriate conventional medical management
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  • Completed diagnostic evaluation without identification of a structural or surgically correctable pathology adequately explaining the current pain
  • Stable analgesic treatment before enrolment
  • Ability to understand the study procedures and complete electronic or written pain diaries
  • Written informed consent A history of endometriosis and/or prior pelvic surgery, including hysterectomy, does not constitute an exclusion criterion, provided that currently active pathology adequately explaining the pain has been excluded.

Who cannot join

  • Participants with a history of spinal cord injury or clinically significant spinal cord lesions are not eligible. This explicit exclusion applies regardless of the presence or absence of prior autonomic dysreflexia.
  • Participants will be excluded in the presence of:
  • Active endometriosis considered sufficient to explain the current pain
  • Pelvic malignancy
  • Active pelvic infection or inflammatory disease
  • Predominant pudendal neuralgia
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  • Identifiable sacral radiculopathy
  • Identifiable pelvic nerve entrapment or injury
  • Predominant ilioinguinal, iliohypogastric or genitofemoral neuropathy
  • Predominant pelvic-floor myofascial pain
  • Spinal, musculoskeletal or hip pathology considered sufficient to explain the symptoms
  • Another identifiable condition requiring specific causal treatment
  • Pregnancy
  • Contraindication to electrical stimulation
  • Inability to comply with the study protocol
  • Spinal Cord Injured peoples

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Marc Possover, MD, PhD, PhD MD contact

+41797507995

m.possover@possover.com

Switzerland1 site
  • Possover International Medical Center AG

    Zurich, Canton of Zurich, 8001

    Possover AG, MD PhD, +41797507995, m.possover@possover.com

    Marc Possover, MD PhD

Other trials in Switzerland

About this study

Official title: Transcutaneous Genital Nerves Electrical Stimulation for Treatment-Refractory Chronic Genital and/or Visceral Pelvic Pain in Women: A Clinical Study

This study will explore whether non-invasive electrical stimulation can reduce chronic genital pain, deep pelvic pain, or both in adult women whose symptoms have persisted for at least six months despite conventional treatment.

Approximately 50 women will participate at several clinical centers. After recording their pain for two weeks, participants will use a portable electrical stimulation device at home for 12 weeks. Two adhesive electrodes will be placed on intact skin beside the vulva. Stimulation will be applied for 30 minutes twice daily, at an individually adjusted, comfortable intensity. No surgery or implantation is required.

Read more

The main outcome is the proportion of participants achieving at least a 30% reduction in their main pain symptom after 12 weeks. Researchers will also assess daily functioning, quality of life, pain medication use, and side effects. Follow-up assessments will take place three and six months after treatment ends.

All participants will receive stimulation; there is no comparison group. This exploratory study aims to assess safety, tolerability, and preliminary signs of benefit to guide a future controlled trial.

Read the detailed description

GNS-PAIN is a prospective, multicenter, single-arm proof-of-concept study investigating transcutaneous perivulvar electrical stimulation in adult women with treatment-refractory chronic genital pain, deep visceral pelvic pain, or both. The study aims to estimate the proportion of participants experiencing clinically meaningful pain improvement and to assess feasibility, safety, and tolerability.

Eligible participants have experienced pain for at least six months despite appropriate conventional medical management. A diagnostic evaluation must exclude an active condition requiring specific causal treatment, such as active endometriosis adequately explaining the current symptoms, pelvic malignancy, infection, or identifiable pelvic nerve entrapment or injury. Previous endometriosis or pelvic surgery does not itself preclude participation. Participants must have an average baseline pain intensity of at least 4 on a numerical rating scale from 0 to 10 in their designated main pain domain.

Genital pain and visceral pelvic pain will be assessed separately. Before treatment begins, each participant will have an index pain domain designated as either genital or visceral pelvic pain. For participants with both types of pain, the more burdensome domain will be selected. This designation will remain unchanged throughout the study and will determine the primary outcome.

Following screening and informed consent, participants will complete a 14-day baseline period, recording daily pain intensity and analgesic medication use. They will then receive training in device operation, electrode placement, stimulation intensity adjustment, and safety precautions before beginning 12 weeks of home-based treatment.

Stimulation will be delivered using a portable transcutaneous electrical nerve stimulation (TENS) device and two self-adhesive electrodes placed on intact skin approximately 2-3 cm lateral to the vulva. Neither electrode will be placed on the clitoris or vulvar or vaginal mucosa. The intervention involves no intracavitary electrode, skin penetration, or implantation.

The stimulation frequency will be 20 Hz. Participants will gradually increase the intensity until a mild tingling sensation is perceived and then slightly reduce it to maintain comfortable stimulation. Treatment sessions will last 30 minutes and will be performed twice daily, in the morning and evening. Device use and electrode placement will be standardized across participating centers through a dedicated stimulation manual.

The primary endpoint is the proportion of participants achieving at least a 30% reduction in mean daily pain intensity in their prospectively designated index pain domain at Week 12. The mean score from the final seven days of treatment will be compared with the mean score from the 14-day baseline period.

Secondary outcomes include the proportion achieving at least 50% pain reduction, changes in mean and worst pain intensity, pain interference with daily activities, Patient Global Impression of Change, analgesic medication use, and health-related quality of life. Associated urinary, bowel, and sexual symptoms will also be assessed. Exploratory analyses will examine responses separately in participants with predominantly genital pain, predominantly visceral pelvic pain, and mixed genital-visceral pain.

Follow-up assessments will take place three and six months after completion of treatment, without continued study stimulation, to assess persistence or loss of any observed benefit. Adverse events, including skin irritation, stimulation-related discomfort, and worsening pain or pelvic symptoms, will be monitored throughout treatment and follow-up. Stimulation will be discontinued if clinically significant or intolerable treatment-related adverse effects occur.

The proposed rationale is that stimulation of sensory pathways in the genital region may influence pelvic pain processing. However, recruitment of specific deep pelvic autonomic structures has not been demonstrated with this skin-electrode configuration, and analgesic efficacy in the study population remains unproven.

There is no control or sham-stimulation group. Accordingly, observed improvements cannot be conclusively attributed to stimulation rather than placebo effects, natural symptom fluctuations, or regression to the mean. The findings will provide preliminary response estimates and feasibility information to inform the design of a subsequent randomized, sham-controlled trial.

Being tested
Transcutaneous Genital Nerves Stimulation
Keywords
Genital Nerves Stimulation, Chronic Pelvic Pain, Refractory Genital Pain, Vulvodynia, Genital Pain, Pelvic Neuromodulation, GNS Procedure, Neuropelveology
Medical subject headings
Vulvodynia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Transcutaneous Genital Nerves StimulationDevice

    Transcutaneous genital nerve stimulation (GNS) will be administered using an external electrical nerve stimulation device connected to bilateral adhesive skin electrodes positioned approximately 2-3 cm lateral to the vulva on intact perivulvar skin.

    Stimulation will be delivered at a frequency of 20 Hz for approximately 30 minutes twice daily. The stimulation intensity will be individually adjusted to produce a comfortable tingling sensation and then slightly reduced to maintain tolerability.

    Following initial instruction, participants will self-administer the treatment at home according to the study protocol. No vaginal or mucosal electrodes, surgical procedures, or implanted devices will be used.

Study groups in NCT07884305
Study groupRoleWhat they receive
Transcutaneous Genital Nerves StimulationExperimentalParticipants will receive bilateral transcutaneous genital nerve stimulation (GNS) using adhesive skin electrodes placed on the perivulvar skin, approximately 2-3 cm lateral to the vulva. Stimulation will be administered at 20 Hz for approximately 30 minutes twice daily. Stimulation intensity will be adjusted to a comfortable sensory level. The intervention aims to evaluate the feasibility, safety, and preliminary therapeutic effects of GNS in women with refractory chronic genital and/or visceral pelvic pain.
Receives: Device: Transcutaneous Genital Nerves Stimulation

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Genital and/or Visceral Pelvic Pain Intensity

    Change in patient-reported pain intensity from baseline, assessed using a 0-10 Visual Analog Scale (VAS), where 0 represents no pain and 10 represents the worst imaginable pain. Genital and visceral pelvic pain will be assessed separately, according to the symptoms present at baseline. Higher scores indicate greater pain intensity. A reduction in score indicates improvement.

    Measured: Baseline and 12 weeks after initiation of treatment

Secondary outcomes (5)
  1. Patient Global Impression of Improvment (PGI-I)

    Patient-reported overall improvement assessed using the 7-point PGI-I scale, ranging from 1 (very much better) to 7 (very much worse).

    Measured: Baseline and 12 weeks after initiation of treatment

  2. Change in Sitting Tolerance

    Change in the maximum duration of sitting tolerated before pain becomes intolerable, measured in minutes and compared with baseline.

    Measured: Baseline and 12 weeks after initiation of treatment

  3. Change in Health-Related Quality of Life assessed by the EQ-5D-5L Visual Analogue Scale (EA VAS)

    Change from baseline in self-reported health status assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L), specifically its visual analogue scale (EQ VAS). The EQ VAS ranges from 0 (worst imaginable health) to 100 (best imaginable health). Higher scores indicate better self-reported health status. The outcome is the change in EQ VAS score from baseline to 12 weeks.

    Measured: Baseline and 12 weeks after initiation of treatment

  4. Proportion of Participants Achieving at Least 50% Pain Reduction

    Percentage of participants achieving a reduction of at least 50% in their prespecified target pain score compared with baseline, measured on a 0-10 pain scale.

    Measured: Baseline and 12 weeks after initiation of treatment

  5. Incidence of Treatment-Related Adverse Events

    Number and proportion of participants experiencing treatment-related adverse events, including skin irritation, discomfort during stimulation, or worsening of pelvic or genital pain.

    Measured: Baseline and 12 weeks after initiation of treatment

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted20 Oct 2026
  2. Study start1 Dec 2026 (estimated)
  3. Primary completion1 Jun 2027 (estimated)
  4. Study completion1 Aug 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Model description
This is a prospective, single-center, single-arm, open-label interventional study evaluating the feasibility, safety, and preliminary efficacy of transcutaneous genital nerve stimulation (GNS) in women with refractory chronic genital and/or visceral pelvic pain. All participants will receive bilateral transcutaneous stimulation using adhesive skin electrodes placed in the perivulvar region. Treatment outcomes will be assessed through changes in pain intensity, patient-reported improvement, and quality of life compared with baseline. No randomization or control group is planned.
Masking
None (open label)
Enrolment
50 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07884305
Sponsor's protocol ID
GNS-Pain-001
Acronym
GNS-PAIN
Status last verified
Oct 2026
First submitted
11 Oct 2026
Last updated
20 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Transcutaneous Genital Nerves Stimulation in people with Refractory Visceral Pelvic Pain and Refractory Genital Pain, run by Prof. Dr. med. Marc Possover at 1 site in Switzerland.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 10 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: opening soon, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Marc Possover, MD, PhD, PhD MD (+41797507995, m.possover@possover.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Genital and/or Visceral Pelvic Pain Intensity (time frame: Baseline and 12 weeks after initiation of treatment). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Oct 2026.

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