Clinical evaluation of modified lateral approach to sciatic nerve block guided by ultrasound and nerve stimulator for foot surgery

Objective To evaluate the feasibility of modified lateral approach to sciatic nerve block guided by ultrasound and nerve stimulator for foot surgery.Methods Sixty-two patients of both sexes,aged 18-60 yr,with body mass index ＜ 30 kg/m2,of ASA physical status Ⅰ-Ⅲ,scheduled for elective foot surgery,were included in the study.Anesthesia was induced with iv propofol 2-4 mg/kg and sufentanil 0.2-0.4 μg/kg.The laryngeal mask airway was inserted and the patients were mechanically ventilated.Sevoflurane was inhaled continuously.Modified lateral approach to sciatic nerve block was performed with 0.3 ％ ropivacaine 30 ml under the guidance of the ultrasound combined with nerve stimulator.Rocuronium 0.6 mg/kg and propofol 1-2 mg· kg-1 · h-1 were administered after completion of sciatic nerve block.Additional sufentanil 0.10-0.15 μg/kg was intravenously injected immediately after skin incision and rocuronium 0.15 mg/kg was injected intravenously at 1 h intervals.The depth of puncture and time for puncture and success rate of puncture were recorded.Sensory block was assessed after the patients regained consciousness completely.Nerve injury,hematoma at the puncture site and infection within 72 h after surgery were recorded.Results The time for puncture was (40 ± 17) s.The depth of puncture was (5.8 ± 0.7) cm.The success rate of puncture at first attempt was 77 ％.The rate of complete sensory block was 100％.The post-operative follow-up showed that no patients developed nerve injury,hematoma or infection.Conclusion Modified lateral approach to sciatic nerve block guided by ultrasound and nerve stimulator is safe and effective for foot surgery. Key words: Sciatic nerve;  Nerve block;  Ultrasonography;  Transcutaneous electric nerve stimulation