Effectiveness of Combined Lumbar Plexus -Sciatic Nerve Block Compare with Spinal Block in Patients Undergoing Unilateral Knee Arthroplasty - ประสิทธิผลการใช้เทคนิค Combined Posterior Lumbar Plexus - Sciatic Nerve Block เปรียบเทียบกับ Spinal Block ในการระงับความรู้สึกของการผ่าตัดเปลี่ยนข้อเข่า

Abstract

             Elderly patients requiring total knee arthroplasty usually have medical illness. To avoid the risk and postoperative side effects, combined posterior lumbar plexus - sciatic nerve block technique has been introduced for total knee arthroplasty. The objective of this study was to compare the effectiveness, side effects and postoperative analgesic effects between combined posterior lumbar plexus - sciatic nerve block and spinal block in patients undergoing knee arthroplasty. It was conducted as a prospective randomized study in sixty patients undergoing elective unilateral knee arthroplasty in Lamphun Hospital. Sixty patients aged 50-70 years old were randomized to undergo either combined posterior lumbar plexus- sciatic nerve block (Group A), or spinal block (Group B). Lumbar plexus and sciatic nerve blocks were performed with 0.5% levobupivacaine; and 0.5% hyperbaric bupivacaine was used for spinal block. Systolic and diastolic
blood pressure, heart rate, and pulse oximetry were recorded. Data on quality of anesthesia, motor and sensory block, time to first analgesic use, sedation, and need for general anesthesia were recorded, along with verbal postoperative pain scores, total morphine consumption in 24 hours and side effects. It was found that the success rate in group A was 93.33% compared to 100.0% for spinal block. Onset sensory and motor blockades were longer in group A. The total intravenous volume in group A was lower. Hypotension
was observed in 20.0% of the group B and needed vasoactive drug. The group A had longer time to first analgesic, lower pain scale at first analgesic, and lower total morphine consumption in 24 hours. There was no significant differences in motor block regression and verbal pain scale at 12 and 24 hours postoperative. In conclusion, combined posterior lumbar plexus - sciatic nerve block provided adequate intraoperative anesthesia, minimal side effect, minimal change of blood pressure and better postoperative
analgesia as well as lower morphine consumption 24 hours postoperative than spinal block. This procedure should be a suitable alternative for total knee arthroplasty in patients with underlying medical condition.

Key words: spinal block, combined posterior lumbar plexus-sciatic nerve block, regional anesthesia