Ultrasound-guided Dual TAP Block: Magnetic Resonance (MR) Evaluation of the Distribution of Local Anesthetic

Study Overview
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Brief Summary
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Using Magnetic resonance (MR) scanning and ultrasonography the investigators wish to investigate, in what way a known volume of local anesthetic injectate will be distributed in the transverse abdominis plane (TAP) in young healthy male volunteers. The investigators compare the anatomical distribution of the local anesthetic injectate in the TAP when performing an ultrasound-guided classical TAP block and a Dual TAP block. The investigators also want to compare the spread of anesthetized frontal dermatomes when performing an ultrasound-guided classical TAP block and a Dual TAP block.

Detailed Description
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There has been much debate as to what extent the classical TAP block will anesthetize more than the frontal dermatomes (TH10-Th12/L1). Some cadaver studies have been performed with injection of dye in the classical TAP. However, it is still not clear whether a single injection of local anesthetic in the classical TAP block position will reach the more cephalad and medial intercostal TAP plexus (Th6-Th9). In this study the investigators use MR scanning and ultrasonography to investigate in what way a known volume of local anesthetic injectate will be distributed in the transverse abdominis plane (TAP) in young healthy male volunteers. The investigators compare the anatomical distribution of the local anesthetic injectate in the TAP when performing an ultrasound-guided classical TAP block and a Dual TAP block. The investigators also want to compare the spread of anesthetized frontal dermatomes when performing an ultrasound-guided classical TAP block and a Dual TAP block.

Official Title
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Dual TAP Block Characteristics - Evaluation of Local Anesthetic Distribution by MR Scanning

Conditions
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Pain, Postoperative

Intervention / Treatment
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* Drug: Bupivacaine
* Procedure: Injection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy male 18 years old or more had no previous abdominal surgery no regular medication no coagulation disorders no claustrophobia Exclusion Criteria: if the volunteer is not able to accept an uncomplicated administration of a classical (single) or dual TAP block

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Dual TAP block<br>Dual TAP block on one side on the abdomen. Classical (or single) TAP on the contra lateral side of the abdomen; supplemented with a sham injection to ensure double blindness. | Drug: Bupivacaine<br>* On both sides of the abdomen 30 ml of bupivacaine 2.5 mg/ml will be injected. This is a total of 60 ml of bupivacaine 2.5 mg/ml.<br>* Other names: Local anesthetic;Procedure: Injection<br>* Injection under ultrasound-guidance<br>* Other names: Nerve blocks;|
| Active Comparator: Classical (or single) TAP block<br>Dual TAP block on one side on the abdomen. Classical (or single) TAP on the contra lateral side of the abdomen; supplemented with a sham injection to ensure double blindness | Drug: Bupivacaine<br>* On both sides of the abdomen 30 ml of bupivacaine 2.5 mg/ml will be injected. This is a total of 60 ml of bupivacaine 2.5 mg/ml.<br>* Other names: Local anesthetic;Procedure: Injection<br>* Injection under ultrasound-guidance<br>* Other names: Nerve blocks;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distribution of local anesthetic evaluated by MR scanning |  | 30 minutes after administering the TAP blocks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spread of anesthetized frontal dermatomes |  | 30 minutes after administering the TAP blocks |