[Combined subarachnoidal block and continuous femoral nerve block for two patients undergoing bilateral simultaneous total knee arthroplasty].

We administered combined spinal anesthesia plus bilateral femoral nerve block in two cases undergoing bilateral simultaneous total knee arthroplasty. Although epidural catheters must be removed before anticoagulant treatment can be performed after surgery, femoral nerve block, poses minimal hindrance to anticoagulant therapy. Because femoral nerve block alone cannot provide sufficient postoperative pain relief after total knee arthroplasty, additional sciatic nerve block, spinal anesthesia, opioid administration, or some other means of analgesia is necessary. A combined femoral nerve block plus sciatic nerve block is useful. A large quantity of local anesthetic is required for this purpose, and its application is difficult in bilateral simultaneous surgery. Spinal anesthesia can be used to reduce the quantity of the local anesthetic, and intrathecal morphine can be used to prolong the pain relief. However, intrathecal morphine can cause itching and late respiratory depression. Respiratory depression did not occur in either of the present patients, although case 2 experienced some itching. In conclusion, combined bilateral femoral nerve block with spinal anesthesia poses minimal hindrance to postoperative anticoagulation therapy and enables control of postoperative pain in patients undergoing bilateral simultaneous total knee arthroplasty.