Interest of a Bi-truncal Nerve Block (Femoral + Sciatic) Extended, Systematically Associated With General Anesthesia, in the Femoropopliteal Bypass: Study of Post-operative Analgesia and Peripheral Circulation Downstream

The aim of this study is to assess, in patients scheduled for femoropopliteal bypass, the benefit of a double peripheral nerve block (femoral + sciatic) with levobupivacaine and clonidine in a single dose, performed before induction of general anaesthesia, on analgesia postoperatively assessed by morphine consumption. Applied to the patient at the beginning of general anesthesia, this technique could allow one hand, to reduce the need for opiates, on the other hand - due to anesthetized limb vasodilation - to improve tissue perfusion downstream.

Inclusion Criteria: * Patients to benefit a planned femoropopliteal bypass through PAOD stage II or III. * Aged 18 to 80 years. * Having given their consent. * Affiliated with a social security scheme. Exclusion Criteria: * Patients with PAOD stage I or IV. * Chronic respiratory failure. * Severe coronary insufficiency. * Renal or hepatic impairment. * Patients with chronic pain or preoperative long-term opioid treatment. * Patients with cognitive impairment (judged by the investigator) that may interfere with: * informed consent, * the collection of endpoints, * the use of patient-controlled analgesia. * Severe abnormality of hemostasis (platelets \