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.

Use of the Shamrock technique to place a lumbar plexus block with injection of 20 mL 2% Lidocaine-adrenaline added gadolinium.

Use of the Lumbar Ultrasound Trident technique to place a lumbar plexus block with injection of 20 mL 2% lidocaine-adrenaline added gadolinium.

Time for performance of lumbar plexus block in seconds from placement of the ultrasound transducer on the skin until the block needle is pulled out after injection of local anesthetics.

Estimated 0 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Needle feeds are defined as retraction of needle followed by new feed of the needle disregarding the number of skin punctures.

Estimated 0 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Estimated 1 minute after block placement. Presented 10 months after the last visit of the last volunteer.

Blood samples are withdrawn 0, 5, 10, 20, 40, 60, and 90 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Measured 5 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Cost-effectiveness estimated as extra expense per successful lumbar plexus block and calculated as incremental cost-effectiveness ratio (ICER).

Calculated two weeks after the last visit of the last volunteer. Presented 10 months after the last visit of the last volunteer.

Sensor block (cold, warm, touch, and pain) of the dermatomes T8-S3 and of the femoral nerve and the lateral femoral cutaneous nerve.

Tested 30 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Motor block of the femoral nerve (knee extension), the obturator nerve (hip adduction), the superior gluteal nerve (hip abduction), and the sciatic nerve (knee flexion) estimated as active resistance against movement of the relevant joint and with sphygmomanometer of the relevant joint as maximal voluntary isometric contraction with dynamometer (mmHg).

Tested 40 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Success rate defined as motor block of the femoral nerve (knee extension) and the obturator nerve (hip adduction) and reduced sensory of the lateral femoral cutaneous nerve (middle of the lateral side of the thigh).

Tested 30 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Defined as above after lumbar plexus block with the Shamrock technique for motor response on electrical nerve stimulation above respectively below 0,5 milliampere (mA).

Tested 30 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Estimated 10-30 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

Estimated 10-30 minutes after block placement. Presented 10 months after the last visit of the last volunteer.

The depth in cm from the injection site in the skin to the needle tips position during injection. of local anesthetics

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

Department of Anesthesiology and Intensive Care Medicine, Aarhus University Hospital, Noerrebrogade 44, DK-8000 Aarhus C, Denmark

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