To Assess Analgesia Provided by Continuous Sciatic Nerve Block in Patients With Hypertensive Leg Ulcer

Hypertensive leg ulcer, also called Martorell ulcer, represents 1 to 15% of leg ulcers in hospital. These ulcers are painful, long to heal, and hospitalization is sometimes necessary for analgesia and debridement of necrotic tissue. Strong opioids are often required, and are responsible of many side effects. Martorell ulcer arises predominantly in women over 60 years of age, with history of vascular disease, and therefore with a higher risk of adverse event. Pain is also part of the physiopathology, inducing a vasospasm which increases ulcer extension and ischemia. This is why pain management is one of the main challenge in treatments of these ulcers. Continuous nerve block of lower limbs are often used during per and postoperative orthopaedic surgery. Few adverse events and rare serious adverse events related to local anesthesic are reported (respectively \<1% and \<1/1000), and few adverse events related to catheter are reported (\<1%). Its benefits have been proved on post-operative pain management and reeducation. The aim of this study is to assess analgesia provided by continuous sciatic nerve block, in patients with hypertensive leg ulcer, during hospitalization. Thirty patients will be enrolled on a 3-years period. They will receive a continuous sciatic nerve block with ropivacaïne 0,2%, during 7 days. Pain intensity will be assessed by 4 datas : numerating rating scale (NRS) at rest, during wound care, maximal and mean. These datas will be collected over two 3-days period : the first 3 days of hospitalization, in which pain treatment will be prescribed depending on pain intensity of the patient ; and the first 3 days of ropivacaïne treatment. The main evaluation criteria will be at least a 50% decrease of one of the pain NRS when receiving ropivacaïne. Time to healing, microcirculation evolution measured by Transcutaneous Oxygen Pressure (TcPO2), and quality of life of patients will be collected over a 6 months follow-up.