Nerve Stimulator Guided Psoas Compartment Block(PCB) Combined With Sciatic Nerve Block For Lower Extremity Minor Surgery

Objective:The success rate of lower extremity nerve block could be improved by our experience in psoas compartment approached lumbar plexus block(PCB), drug capacity and concentration research, as well as a new method of sciatic nerve block. Thus, patients’comfort and satisfaction could be improved as well.Methods:Patients undergoing lower extremity minor surgery during2009-2010were randomly divided into2groups with25patients in each group in both two parts. PCB and sciatic nerve block were performed in both groups. Part Ⅰ:The traditional dose group (Group T):30ml0.5%ropivacaine for lumbar plexus,1.5%lidocaine15ml+0.5%ropivacaine10ml for sciatic nerve. Maximum dose group (Group M):4mg/kg ropivacaine was diluted to a concentration of0.5%, with1.5%lidocaine20ml. Lumbar plexus and sciatic nerve get half from the total capacity. Sensory and motor effects was evaluated every5minutes in the next30minutes by an independent blinded observer. Mid-term(3-6months) evaluation was follow-up. Positioning time, onset time, success time and success rate, vasoactive agents dose, remedies, and complications were recorded. Part Ⅱ:Single-point group (Group S):When performing sciatic nerve block, agents as Group M Part Ⅰ was injected after plantar flexion had been evoked. Double-point group (Group D):Plantar flexion or dorsiflexion was evoked first, then move the tip of the needle or remove the needle to subcutaneous to re-locate another reaction. Give the agents as Group S if another reaction could be evoked by moving the tips of the needle. If another reaction was evoked after removing the needle to subcutaneous, agents as Group M could be given equally to both points. Evaluate and record the results as Part Ⅰ.Results:Part I:Group T had a success rate of68%(17/25) while the maximum dose Group M92%(23/25)(P<0.05). Two cases changed to general anesthesia to finish the surgery, and none of the Group M did. One case of Group T had an accidental vessel injury, and Group M had two. Local anesthetic toxicity occurs in one case of Group M. The two groups had no significant difference in mean arterial pressure, heart rate, regional paresthesia, bilateral blockade and other complications. Part Ⅱ: Group S had a success rate of72%(24/25) while Group D had96%(24/25)(P<0.05). All the cases was finished with the help of local anesthesia. No vessel injury, allergic to agents or anesthetic toxicity happened in either group. Among the mid-term follow-up in Group D (3-6months), regional skin hypoalgesia of superficial peroneal nerve happened in one case of Group D. The sensory and motor sense of the deep peroneal nerve were not involved. The incidence of complications in two groups had no significant difference.Conclusion:When performing PCB, keep coronal plane perpendicular to the bed, judge the quadriceps contraction at patella ligament, then the4mg/kg,0.5%ropivacaine solution could provide better anesthetic effect than traditional dose(20-40ml). In the sciatic nerve block, double-point method provides better blockade effect better than single-point method.