Objective To explore the feasibility of continuous sciatic nerve block via lateral poplit eal approach with single shot femoral nerve block for enhanced recovery after surgery in ankle and foot surgery.Methods Sixty adult patients scheduled for elective ankle and foot surgery were randomly assigned into 2 group (n =30 each):Group A received sciatic nerve block via lateral popliteal approach with a catheter placed and a single shot femoral nerve block under ultrasound guidance followed by patient-controlled postoperative analgesia with 0.2％ ropivacaine through the perineural catheter;Group B received the routine epidural puncture and a catheter placement at L2-3 level followed by postoperative analgesia with 0.2％ ropivacaine through the catheter.Systolic blood pressure (SBP),diastolic blood pressure (DBP) and heart beat (HR) were recorded before and after anesthesia.The block efficacy,the volume of fluid influsion during operation and the usage of ephedrine were recorded.The pain severity at rest and upon movement with a 0-10 numeric rating scale (NRS,0 =no pain and 10 =worst possible pain),the modified Bromage score of the motor block of the affected extremity,the number of effective patient-controlled bolus of ropivacaine and the number of need for opioid rescue within 48 h after surgery were assessed.The first time of leaving bed after operation,the length of hospital stay and the occurring of complication related to puncture and analgelsia were also recorded.Results SBP and DBP at each time point after anesthesia were higher in group A than those in group B (P ＜ 0.05).The volume of fluid infusion during operation and the occurence of ephedrine use were less in group A than those in group B (P ＜0.05).There was no indifference in terms of the NRS scores at rest and upon movement,the number of effective patient-controlled bolus of ropivacaine and the number of need for opioids rescue (P ＞ 0.05),but the complications such as nausea and vomiting,urinary retention occurred more in group B (P ＜0.05).The modified Bromage score of the motor block at each time point within 24 h after surgery was lower in group B than that in group B (P ＜ 0.05).The first time of leaving bed after operation and the length of hospital stay were shorter in group A than those in group B (P ＜ 0.05).Conclusions Ultrasound-guided continuous sciatic nerve block via lateral popliteal approach with single shot femoral nerve block can provide exact anesthetic effect with minimal interference on haemodynamics and excelent postoperative analgesia with less influence on movement.It's helpful in the ankle and foot surgery to improve the recovery after surgery.