The Role of Peripheral Afferents in Modulating Post-stroke Central Pain

Inclusion Criteria: 1. Patients aged 18 years and over with no maximum age (blocks are generally very well tolerated in the very elderly) 2. Pain in the upper or lower limb distal enough to be completely covered by a peripheral nerve block 3. Chronic pain for at least 6 months 4. Ischaemic or haemorrhagic stroke for at least 6 months documented clinically and by appropriate imaging (MRI) 5. Post-stroke central neuropathic pain defined as pain occurring in the aftermath of stroke meeting the criteria for probable or defined neuropathic pain according to the NeuPSIG algorithm and with a DN4 screening questionnaire score of at least 4 out of 10. 6. Spontaneous pain intensity greater than or equal to 4 out of 10 on an 11-point numerical scale (EN) at inclusion and randomisation (i.e. just before each block) 7. Patients affiliated to a social security scheme or beneficiaries of such a scheme 8. Stable oral analgesic pharmacological treatment for at least 2 weeks prior to inclusion 9. Acceptance and signing of the informed consent Exclusion Criteria: 1. Inability or unwillingness to sign an informed consent 2. Person subject to a legal protection measure (safeguard of justice, curatorship, guardianship) 3. Patients with ongoing psychiatric pathology (major depression, psychosis) or cognitive disorders that prevent a good understanding of the protocol and questionnaires 4. Pain that is too widespread in one hemicycle or limb and cannot be adequately covered by blocks 5. Ongoing drug or substance abuse 6. Language (aphasia) or comprehension disorders, illiteracy 7. Moderate to severe renal or hepatic impairment 8. Contraindication to local anaesthetics for use in perineural blocks (infection or acute inflammation in the injection area, known allergy). 9. Pregnancy or breastfeeding 10. Known hypersensitivity to lidocaine, levobupivacaine, amide-linked local anaesthetics or to any of the excipients contained in the specialities used in the study. 11. Patients with recurrent porphyria or severe hypotension contraindicating treatment with lidocaine and/or levobupivacaine 12. Current treatment with antiarrhythmic drugs causing torsades de pointes (amiodarone, disopyramide, quinidinics, sotalol...) or with antiarrhythmic drugs with local anaesthetic activity (mexiletine or class III antiarrhythmic drugs) and cannot be discontinued. 13. Too little pain at the time of the blocks (\< 4 out of 10) 14. Need to modify analgesic pharmacological treatment at the beginning or during the study