Comparison of the Combined Femoral and Lateral Femoral Cutaneous Nerve Block Plus Popliteal Block with Spinal Anesthesia for Thigh Tourniquet Pain During Foot or Ankle Surgery: A Randomized Clinical Trial.

Background: A pneumatic thigh tourniquet is routinely used during lower-extremity orthopedic surgeries to provide a bloodless field. When using peripheral nerve blocks, tourniquet-related thigh pain and discomfort limit their routine use as an anesthetic method.

Objectives: The aim of the present prospective, randomized study was to compare the efficacy of combined femoral nerve/lateral femoral cutaneous nerve block technique and spinal anesthesia on intraoperative thigh tourniquet pain.

Methods: We studied 60 American Society of Anesthesiologists physical status I-II patients scheduled for orthopedic surgery on the foot or ankle using a pneumatic thigh tourniquet. They were randomly divided into two equal groups. The peripheral nerve block group received a combined popliteal, femoral, and lateral femoral cutaneous nerve block under ultrasound-guidance. In both groups, the level of sensory blockade was determined by the pinprick test. The block performance time, anesthetic effect time, intraoperative tourniquet pain scores, the amount of fentanyl and ketamine, surgery duration, and patient's satisfaction were recorded.

Results: The patients' characteristics were comparable in the two groups. The mean duration of block performance and anesthetic effect, intraoperative tourniquet pain scores, and the amount of intravenous analgesics in the peripheral nerve block group were significantly greater than those in the spinal anesthesia group. Patient satisfaction was similar in both groups.

Conclusions: Spinal anesthesia is significantly more effective than the peripheral nerve block method in reducing thigh tourniquet pain. A combined femoral and lateral femoral cutaneous nerve block with popliteal block can improve thigh tourniquet tolerance if supplemented with intravenous analgesics.