Evolution of Different Sensitivity Levels in Patients With Chronic Neuropathic Pain in the Pelvi-perineal Region After Treatment With High-concentration Capsaicin Patches (CAPSASENS)

The primary objective of this study will be to demonstrate a change in pain sensitization parameters before and after the application of the high-concentration capsaicin patch.

Study Overview

• Status: Not yet recruiting
• Conditions: Neuropathic Pain; Nociplastic Pain
• Intervention / Treatment: Other: Quantitative Sensory Testing and questionnaires

Detailed Description

Category 2 Study (Interventional Research with Minimal Risks and Constraints), monocentric, uncontrolled, non-randomized, open-label and prospective.

This study involves conducting tests and questionnaires before and 1 month after the application of a patch administered as part of standard clinical practice.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Amélie LEVESQUE, MD; Phone Number: +33240083912; Email: amelie.levesque@chu-nantes.fr

Study Locations

• France
  • Nantes, France
    • Nantes University Hospital
    • Contact: Nantes University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Men or women ≥ 18 years old.
• Patients suffering from chronic pelvi-perineal neuralgia (>3 months) with a DN4 score ≥4 at the inclusion visit, with or without symptoms of central sensitization, and with an indication for topical treatment with high-concentration capsaicin patch (PCHC).
• Patients who have signed the informed consent form for the study at the inclusion visit.
• Women must meet one of the following criteria at the time of inclusion:
• Use adequate contraceptive measures;
• or Be postmenopausal (aged over 50 years with amenorrhea for at least 12 months after discontinuation of all exogenous hormonal treatments);
• or (If aged under 50 years) have been amenorrheic for at least 12 months after discontinuation of exogenous hormonal treatments, with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels consistent with postmenopausal levels;
• or Have undergone irreversible surgical sterilization (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), with documentation of the procedure.

Exclusion Criteria:

• Patients under guardianship, curatorship, or legal protection.
• Pregnant or breastfeeding women.
• Patients with contraindications to the use of the high-concentration capsaicin patch (PCHC): application on damaged skin, hypersensitivity to any of its components.
• Patients simultaneously starting a treatment that may influence central sensitization (e.g., antidepressants, antiepileptics, psychotherapy, physical activity, transcutaneous electrical nerve stimulation).
• Patients not affiliated with the French Social Security system.
• Patients with insufficient cooperation and/or understanding to strictly comply with the protocol requirements.
• Patients who have taken analgesics within the 12 hours prior to measurements.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Pain sensitization parameter testing; Pre-inclusion visit (routine care consultation): Verification of inclusion and exclusion criteria. Inclusion visit (Day 0): Consent signing, questionnaires (ConvergencePP Score/Central Sensitization Inventory, DN4), and a series of tests, followed by the application of the high-concentration capsaicin patch (PCHC) (performed during routine care). Day 30 visit (±7 days): Questionnaires (same as V1 + PGI-c) and a series of tests.

Other: Quantitative Sensory Testing and questionnaires; Quantitative Sensory Testing and questionnaires

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite criterion	Composite criterion constructed from a Principal Component Analysis including the differences between Day 0 (before patch application) and Day 30 in pain perception thresholds (to cold, heat, pressure, and mechanical stimulation) in both the area treated with the high-concentration capsaicin patch and the corresponding dermatome, as well as the change in the pain receptive field area in the treated zone and the area under the curve of temporal summation measurements.	Difference between Day 0 and Day 30

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (1)	Difference in pressure pain thresholds in the treated area	Between before and 30 days after patch application
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (2)	Difference in mechanical stimulation pain thresholds	Between before and 30 days after patch application
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (3)	Difference in cold pain thresholds in the treated area	Between before and 30 days after patch application
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (4)	Difference in heat pain thresholds in the treated area	Between before and 30 days after patch application
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (5)	Difference in pain receptive field area	Between before and 30 days after patch application
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (1)	Difference in pressure pain thresholds in an area of the dermatome not directly treated by the patch: Ipsilateral retro-malleolar groove (S2 root) for inferior cluneal nerve neuralgia treatment,; Posterior iliac crest relief, 7 cm from the midline (L1) for ilio-inguinal or ilio-hypogastric neuralgia treatment,; Perineal body (S4) for sacrococcygeal plexus neuralgia treatment.	Between before and 1 month after patch application.
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (2)	Difference in mechanical stimulation pain thresholds in an area of the dermatome not directly treated by the patch	Between before and 1 month after patch application.
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (3)	Difference in cold pain thresholds in an area of the dermatome not directly treated by the patch.	Between before and 1 month after patch application.
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (4)	Difference in heat pain thresholds in an area of the dermatome not directly treated by the patch.	Between before and 1 month after patch application.
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (5)	Difference in the area under the curve of temporal summation measurements in the treated area	Between before and 1 month after patch application.
Measure the effect of the high-concentration capsaicin patch (PCHC) on spinal sensitization (6)	Difference in the duration of pain persistence after the end of temporal summation (in seconds).	Between before and 1 month after patch application.
Measure the patient's therapeutic response to the treatment	Patient Global Impression of Change (PGI-C). The therapeutic response is defined as a patient who scores 1 to 3 on the PGI-C.	Day 30
Evaluate the predictive value of temporal summation with regard to the therapeutic response to the high-concentration capsaicin patch	Investigation of a relevant threshold for temporal summation to predict the therapeutic response. Quantification of the positive predictive value.	Between before and 1 month after patch application.
Measure the correlation between Convergences PP scores, CSI, and semi-objective sensitization data	Measure the correlation between Convergences PP scores, CSI, and semi-objective sensitization data. The Convergences PP score is a clinical questionnaire used to diagnose sensitization in the pelvic region. A score is considered positive from 5/10 (sensitivity = 95%, specificity = 87%). The Central Sensitization Inventory (CSI) is a self-administered questionnaire used to diagnose central sensitization. A score is considered positive from 40/100. Correlations between the Convergences PP score, CSI, and semi-objective sensitization data (pain thresholds and temporal summation) will be measured using Spearman's correlation coefficient to explore the relationships between these variables.	Between before and 1 month after patch application

Collaborators and Investigators

• Sponsor: Nantes University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: June 15, 2026
• First Submitted That Met QC Criteria: June 15, 2026
• First Posted (Actual): June 22, 2026

Study Record Updates

• Last Update Posted (Actual): June 22, 2026
• Last Update Submitted That Met QC Criteria: June 15, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Quantitative Sensory Testing; Sensitization; 8% capsaicin patch; Temporal Summation
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Neuralgia; Nociplastic Pain; Health Care Quality, Access, and Evaluation; Investigative Techniques; Epidemiologic Methods; Data Collection; Health Care Evaluation Mechanisms; Quality of Health Care; Public Health; Environment and Public Health; Surveys and Questionnaires
• Other Study ID Numbers: RC25_0536

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No