The main objective of the trial is to complete a double-blinded randomized controlled trial with crossover design of a one-injection nerve block of the lower part of the lumbar plexus and the upper part of the sacral plexus (Suprasacral Parallel Shift, SSPS) to achieve analgesia of the femoral nerve, the obturator nerve, the lumbosacral trunk, and spinal nerve L1 with SSPS guided by ultrasound/MR image fusion vs. SSPS guided by ultrasound by estimating sensory block of in healthy volunteers by estimating the sensory block of dermatomes of the terminal nerves in healthy volunteers.~The secondary objective is to estimate a) preparation and b) procedure time, c) injection site and d) depth, e) discomfort, f) change in MAP, g) plasma lidocaine pharmacokinetics, h) motor and i) sensory block, j) perineural and k) epidural spread of lidocaine-epinephrine added gadotorate meglumine on MRI, and l) cost-effectiveness of SSPS guided by ultrasound/MR image fusion vs. SSPS guided by ultrasound.~The investigators hypothesize that block success is higher for SSPS guided by ultrasound/MR image fusion than for SSPS guided by ultrasound.
The main objective of the trial is to complete a double-blinded randomized controlled trial with crossover design of a lumbosacral plexus block with the Suprasacral Parallel Shift technique guided by ultrasound/magnetic resonance (MR) image fusion vs. Suprasacral Parallel Shift guided by ultrasound by estimating sensory block of the femoral nerve, the obturator nerve, the lumbosacral trunk, and spinal nerve L1 in healthy volunteers.