BACKGROUND: We evaluated whether the unilateral spinal anesthesia using a 26-gauge Quincke needle provides more adequate or hemodynamically stable spinal anesthesia than the conventional spinal anesthesia in orthopedic patients. METHODS: Fifty-eight ASA 1 or 2 patients aged from 18 to 65 years undergoing unilateral lower limb surgery were included. All patients were placed in the lateral position with the side to be operated on dependent and received a 8 mg 0.5% hyperbaric bupivacaine through a 26-gauge Quincke spinal needle for 80 seconds. Local anesthetic was injected with the needle orifice turned toward the dependent side, then the immediate supine position (conventional group, n = 34), or the lateral position (unilateral group, n = 24) was maintained for 15 minutes. Hemodynamic variables, as well as loss of cold, pinprick sensation and motor block on both sides were recorded. RESULTS: All the 23 patients in the unilateral group had adequate spinal anesthesia, whereas 6 out of 34 patients of the conventional group (17.6%) had inadequate to failed spinal anesthesia (P < 0.05). There were significant differences in the degree of motor block on the dependent side of lower extremities between the two groups. Motor block of grade 0 to 1 on the dependent side were 23.5% and 0% in the conventional and unilateral group, respectively (P < 0.05). Unilateral sympathetic or sensory block were not observed in the unilateral group. No differences in blood pressure, heart rate changes were observed between the two groups. CONCLUSIONS: The present study does demonstrate clinically relevant advantages of a lateral position for 15 minutes, either in terms of adequacy of spinal anesthesia or differential motor block using a 26-gauge Quincke spinal needle in orthopedic patients.
Anesthesia, Spinal* ; Blood Pressure ; Bupivacaine ; Heart Rate ; Hemodynamics ; Humans ; Lower Extremity ; Needles* ; Orthopedics ; Sensation ; Supine Position