[Sciatic nerve block by the lateral route at the level of the popliteal fossa with 0.75% ropivacine: advantages of a more proximal approach].

OBJECTIVES: To assess the efficacy of a sciatic nerve block using a lateral approach 11 cm cephalad to the lateral femoral epicondyle for providing surgical anesthesia and postoperative analgesia in scheduled foot surgery (hallux valgus) after a single injection of 30 mL of 0.75% ropivacaine. METHODS: A block was performed in 30 patients using a point of puncture 11 cm cephalad to the most prominent point of the lateral femoral epicondyle in the groove between the biceps femoris and vastus lateralis muscles. Once the nerve had been located with a stimulator (2 Hz, 0.5 mA), 30 mL of 0.75% ropivacaine was injected. Data recorded were time until block, number of attempts, depth at which the nerve was found, sciatic nerve response obtained, and time until the sensory block was complete. We evaluated quality of anesthesia during surgery, duration of postoperative analgesia, and patient discomfort during performance of the block. RESULTS: Time required to perform the block was 4.3 +/- 1.2 minutes and only one puncture attempt was needed in 27 patients. The nerve was located at 5.5 +/- 0.4 cm, with response located in the common peroneal nerve in 18 patients and in the posterior tibial nerve in 12. The time needed to achieve a full sensory block was 19.3 +/- 5.1 minutes. Twenty-six patients (86%) were very satisfied with the anesthetic quality of the block, 2 were moderately satisfied, and 2 were dissatisfied. Postoperative analgesia lasted 19 +/- 3.4 hours. Four patients reported minimal discomfort during performance of the block. No complications were observed. CONCLUSIONS: The sciatic nerve block from a lateral approach 11 cm cephalad to the lateral femoral epidondyle is an appropriate anesthetic technique for foot surgery. It is safe, effective and easy to perform. Infusion of 30 mL of 0.75% ropivacaine provided adequate anesthesia and long-lasting postoperative analgesia for our patients.