After standard external monitors, pulse oximeter, electrocardiogram, noninvasive blood pressure, were applied on subject's arrival in the operation room. Subjects had an intravenous line placed in the upper extremity. Patients received midazolam (0.015-0.03 mg.kg-1), sulfentanil (0.10-0.15µg.kg-1) by infusion, in divided doses, before lumbar plexus and sciatic nerve blocking and supplemental 100% oxygen (3 L.min-1) was administered by facemask spontaneously breathing during the procedure. The procedure was performed by two anesthesiologists with extensive experience in nerve block. After sterile preparation and draping, PNBs were administered using a 21-gauge, 100-mm Stimuplex block needle and a nerve stimulator. A posterior approach to lumbar plexus block was performed with patient in the lateral decubitus position and after a quadriceps muscle response had been identified with nerve stimulator settings at 2 HZ frequency and current between 0.3 and 0.5 mA, and 0.2% ropivacaine (25-30 mL) was injected slowly. Sciatic nerve block was performed in the same position after a twitch of hamstrings, soleus, foot, or toes, had been elicited using the similar current, and 0.2% ropivacaine (15-20 mL) was injected slowly.