Study Evaluating the Analgesic Efficacy of Capsaicin 8% Patches in Chronic Coccygodynia.

Inclusion Criteria: * \>18 years old at the pre-inclusion visit * Presenting with chronic coccygodynia: pain in the coccygeal region, increased by sitting and or when rising from a sitting position and pain over the last ten days of intensity greater than or equal to four on the eleven-point numerical scale (from zero to ten) and having been present for more than 3 months. * Failure of previous treatments: NSAIDs, pressure-relieving cushions and/or infiltration or having a contraindication to these treatments, or not wishing to receive these treatments * Have never been treated with an 8% capsaicin patch for this indication * With at least one clinical sign suggestive of neuropathic pain (burning, painful cold, numbness, tingling, electric discharge, allodynia of the gluteal groove, allodynia to pressure on the coccyx) * Proficiency in reading and writing the French language * Be affiliated to the social security system * Have signed an informed consent form * Women must meet one of the following criteria at the time of inclusion: * be using adequate contraceptive measures, and have a negative pregnancy test (specify if urine or blood test) prior to receiving the first dose of trial medication; * or be post-menopausal (aged over 50 with amenorrhoea for at least 12 months after stopping all exogenous hormonal treatments) * or (if under 50) have been in amenorrhoea for at least 12 months after stopping all exogenous hormone treatments and with luteinising hormone (LH) and follicle stimulating hormone (FSH) levels corresponding to post-menopausal levels. * or have undergone irreversible surgical sterilisation by hysterectomy, bilateral oophorectomy or bilateral salpingectomy (this operation must be documented). Exclusion Criteria: * Coccygodynia accompanied by a dermatological lesion in the intergluteal cleft (psoriasis, pilodinial cyste, wound) * Patients with other major pain disorders likely to interfere with pain assessment * Hypersensitivity to capsaicin or to one of the excipients * Adults under legal protection (guardianship, curatorship, legal protection) * Pregnant or breast-feeding women * Patients who have undergone total coccygectomy