Testing spinal stimulation for painful forward bending

Inclusion Criteria: * Parkinson's disease validated according to UKPDSBB clinical criteria * Camptocormia defined by a total camptocormia angle (ACT) \> 30° or a greater camptocormia angle (ACS) \> 45° * Camptocormia established for less than 2 years or recently worsening for less than 1 year. * Persistent camptocormia despite optimal drug treatment at the time of inclusion * Pain associated with abnormal posture: VAS ≥ 4/10 during the last 3 months * Stable antiparkinsonian treatment for 4 weeks * Treatment with co-analgesics stable for 4 weeks * Criteria relating to regulation: * Major person * Affiliation to a social security scheme * Adult who has read and understood the information letter and signed the consent form * Women: * Of childbearing age (defined by the CTFG as a fertile woman, after menarche and until menopause, except in cases of permanent sterility (including hysterectomy, bilateral salpingectomy or bilateral oophorectomy)): * using effective contraception according to the WHO (combined hormonal contraception (containing estrogens and progestins), progestin-only contraception, intrauterine device IUD), male or female condoms) for 1 month before inclusion and during the study And, * presenting a negative urine pregnancy test at inclusion - Menopause: menopause according to the CTFG is defined as the absence of periods for 12 months without any other medical cause before the inclusion visit. An elevated follicle-stimulating hormone (FSH) level in the postmenopausal interval can be used to confirm a postmenopausal state in women who are not using hormonal contraception or hormone replacement therapy. However, in the absence of 12 months of amenorrhea, a single FSH measurement is insufficient. Exclusion Criteria: * Atypical parkinsonian syndrome * Contraindication to surgery and anesthetic products * Uncontrolled diabetes * Systemic or local infection * Major cognitive disorders: MOCA \< 25 * Severe psychosis associated with Parkinson's disease * Severe depressive syndrome: MADRS \> 35 * Patient with deep brain stimulation * Patient with a cardiac pacemaker * Patient currently being treated by diathermy or to be treated by diathermy * Severe substance use disorders (alcohol, drugs, medication) * Contraindication to MRI * Obstacle to the placement of a dorsal epidural electrode * Dorsal myelopathy * Severe associated scoliosis * Severe camptocormia defined by an ACT \> 80° * Severe alteration of somesthetic evoked potentials (ESP) in the lower limbs * Pregnant or parturient or breastfeeding woman or proven absence of contraception * Person deprived of liberty by an administrative or judicial decision or person placed under judicial protection/under guardianship or curatorship * History of illness or psychological or sensory abnormality likely to prevent the subject from fully understanding the conditions required for participation in the protocol or preventing them from giving informed consent