Clinical Study Of Combined Lumbar Plexus-Sciatic Nerve Block Using The Peripheral Nerve Stimulator

Objective To observe the clinical efficacy of combined lumbar plexus -sciatic nerve block and unilateral spinal anesthesia for leg surgery and the effects of the addition of fentanyl to local anaesthetics on duration of analgesia and success rate of nerve block .Mesthods 52 patients randomly assigned to three groups. Lumbar plexus and sciatic nerve block were obtained with ropivacaine 0.375% and lidocaine 0.5% using peripheral nerve stimulator in NB1 group and NB2 group. Fentanyl lOOfig was given intravenously into NB1 group. NB2 group received local anaesthetics containing fentanyl lOOug. S group was obtained by spinal injection 10 mg of hyperbaric bupivacaine.Results Mean arterial blood pressure (MAP) did not change in patients of group NB1 and group NB2, whereas in group S, MAP was reduced at 15and 20 min as compared with baseline, P (0.01. Group NB1 and group NB2 had a smaller range of sensory block and a longer duration of analgesia and mortor block than group S, P (0.01. Group NB2 had a longer time of analgesia than group NB1, P (0.05. Group NB1 and group NB2 had a longer time of analgesia than mortor block , P (0.05 and P (0.01. Complete nerve blockade was related to the intensity of the current and was not correlative to the volume of local anaesthetics. Ephedrine use was decreased in group NB1 and group NB2 as compared with group S, P (0.01. Fewer patients required pain treatment in the group NB1 andgroup NB2 than in the group S during the first 24h after the operation, P (0.01. There was no headache, nausea in group NB1 and group NB2. Patient acceptance and the success rate of nerve block were no significently difference among three groups.Conclusion Both combined lumbar plexus -sciatic nerve block and unilateral spinal blockade provide adequate anaesthesia for uinlateral leg surgery, but peripheral nerve block provide minimal effects on hymodynamics, longer duration of analgesia and no side effects of spinal anesthesia. Application of fentanyl to combined lumbar plexus -sciatic nerve block can enhance analgesia by a peripheral mechanism and no effect on prolongation of motor block and success rate of nerve block. When the stimulative current was 0.2~0.3 mA, we had a nearly 100% success rate of complete nerve block with peripheral nerve stimulator.