Is unilateral spinal anesthesia superior to bilateral spinal anesthesia in unilateral inguinal regional surgery?

Background: Unilateral spinal anesthesia is performed to provide restriction of sensory and motor block. Objective: The aim of this study was to compare unilateral and bilateral spinal anesthesia, with regard to limiting the nerve block exclusively to the area of surgery. Methods: This was a prospective, randomised, double-blind study, conducted in 40 consecutive outpatients scheduled for unilateral inguinal regional surgery. Patients in both groups received 0.5 % hyperbaric bupivacaine 15 mg + morphine 0.1 mg. Patients in the unilateral group (Group U) were placed in the lateral decubitus position for 10 minutes (min) on their side to be operated, while patients in the bilateral group (Group B) were placed in the supine position. The pin-prick test was used to assess the times to reach L1, T12 and T10 sensory blocks and the times to reach motor block. In addition, the sensory and motor block recovery times were recorded using a modified Bromage scale. Furthermore, the duration of the operation and the times to first analgesic requirement were noted. Results: There were significant differences between Group U and Group B in the times to reach L1, T12 and T10 dermatome levels of sensory block, and the times to reach motor block using the modified Bromage scale on three levels. However, there was no difference in the time to ambulation, the time to complete sensory regression and the time to first analgesic requirement. Conclusion: The time to reach sensory and motor blocks for unilateral spinal anesthesia could provide an advantage over bilateral spinal anesthesia in inguinal region operations.