Ultrasound-guided lumbar plexus block in volunteers; a randomized controlled trial

Area of Science:

• Anesthesiology
• Regional Anesthesia
• Ultrasound-Guided Procedures

Background:

• Established ultrasound-guided lumbar plexus block (LPB) techniques, like the lumbar ultrasound trident (LUT), sometimes have poor sonographic visibility.
• The shamrock LPB technique offers improved real-time visualization of the lumbar plexus and needle advancement.

Purpose of the Study:

• To compare the outcomes, effectiveness, and safety of the shamrock LPB technique versus the LUT technique.

Main Methods:

• A blinded randomized crossover study involving twenty healthy men.
• Participants underwent both shamrock and LUT ultrasound-guided LPBs using 2% lidocaine–adrenaline.
• Outcomes included block procedure time, discomfort, needle insertions, injectate spread via MRI, sensorimotor effects, and pharmacokinetics.

Main Results:

• The shamrock LPB was significantly faster (238s vs 334s), more comfortable (3 vs 4 NRS), and required fewer needle insertions (2 vs 6).
• Perineural injectate spread on MRI was similar between techniques and correlated with sensorimotor mapping.
• No significant difference in epidural spread (0% vs 5%) or lidocaine pharmacokinetics was observed.

Conclusions:

• The shamrock LPB technique is a faster and more comfortable alternative to the LUT technique.
• The shamrock LPB demonstrates comparable effectiveness and safety to the established LUT method.