Shamrock Versus Lumbar Ultrasound Trident - Ultrasound Guided Block of the Lumbar Plexus

The main objective of the trial is to complete a double-blinded randomized controlled trial of a lumbar plexus block with the Shamrock technique versus the Lumbar Ultrasound Trident technique by estimating the time of performance of lumbar plexus blocks in healthy volunteers. Secondary objectives include a) estimates of number and depth of needle injections, distance of injection site from the midline, minimal electric nerve stimulation to trigger muscular response and the type of response, and volunteer discomfort during block injection, b) measurements of plasma lidocaine and mean arterial blood pressure, c) examinations of sensory block of the dermatomes T8-S3 and motor block of the femoral nerve, the obturator nerve, the hip abductor muscles, and the hamstring muscles, d) success rate of lumbar plexus block, e) perineural and epidural distribution of local anesthetics added contrast visualized on magnetic resonance imaging (MRI) scanning, and f) cost-effectiveness for the Shamrock technique versus the Lumbar Ultrasound Trident Technique for lumbar plexus block in healthy volunteers. The hypothesis is that the Shamrock technique is faster to perform than the Lumbar Ultrasound technique, and that the success rate of the Shamrock technique is equal to or higher than the Lumbar Ultrasound Trident technique.