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.
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
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
30
Quantitative Sensory Testing and questionnaires
Nantes University Hospital
Nantes, France
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.
Time frame: Difference between Day 0 and Day 30
Measure the effect of the high-concentration capsaicin patch on peripheral sensitization (1)
Difference in pressure pain thresholds in the treated area
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
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Time frame: 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.
Time frame: 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
Time frame: 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.
Time frame: 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.
Time frame: 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
Time frame: 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).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Between before and 1 month after patch application