Spinal Anesthesia at the L2-L3 Versus L4-L5 Lumbar Vertebrae With Bupivacaine 0.5% (12.5 mg and 10 mg) Comparing Analgesia and Hemodynamic Stability: A Quasi-experimental Study

Objective: The objective of this study is to compare the outcomes of spinal block quality, hemodynamic stability, and adverse effects profile when giving spinal anesthesia using 10 mg and 12.5 mg of hyperbaric spinal bupivacaine at L2-L3 versus L4-L5 lumbar intervertebral space in bilateral inguinal hernia surgeries. Materials and methods: It is a quasi-experimental study conducted at the anesthesia department of Combined Military Hospital (Malir Cantt), Karachi, from October 2022 to April 2023. A total of 220 patients were divided into the L2-L3 interspace group (n = 110) and the L4-L5 interspace group (n = 110) to be given spinal anesthesia with 0.5% bupivacaine 12.5 mg for the first unilateral hernia correction and to receive 10 mg of 0.5% bupivacaine for the second unilateral hernia correction eight weeks after the first procedure. Primary variables measured were time to complete the sensory block, total duration of the block, and time to first rescue analgesia after block regression. Secondary variables observed were perioperative hemodynamic parameters, including frequency of bradycardia and hypotension. Results: The study concluded that using 12.5 mg of 0.5% bupivacaine in the L2-L3 space was associated with a higher frequency of bradycardia and hypotension while also providing the earliest onset and longest block regression time when compared with the L4-L5 space. Conclusion: We conclude that the L4-L5 interspace is associated with adequate levels of spinal block quality and postoperative analgesia with less frequency of bradycardia and hypotension than the L2-L3 interspace and should be preferred in patients undergoing inguinal hernia surgery under spinal anesthesia.