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

Shamrock Versus Lumbar Ultrasound Trident - Ultrasound Guided Block of the Lumbar Plexus: A Randomized Controlled Trial

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.

Inclusion Criteria:

• Male
• Age ≥ 18 years
• Volunteers who have given their written and oral consent to participate in the study after fully understanding the content and the limitations of the protocol
• Normal healthy volunteer (American Society of Anesthesiology (ASA) Classification I)

Exclusion Criteria:

• Volunteers not able to cooperate for the study
• Volunteers not able to understand Danish
• Daily use of analgesics
• Allergy against the medicines used in the study
• Drug abuse (according to the investigator's judgement)
• Alcohol consumption larger than the recommendations of the Danish National Board of Health
• Volunteers in whom nerve blocks are not possible due to technical reasons
• Volunteers who meet any contraindication for MRI including claustrophobia
• Volunteers who are incompetent, i.e. surrogate consent is not accepted