Spread of Paravertebral Injections in the Lumbar Plexus Area

Study Overview
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Brief Summary
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Lumbar paravertebral block (LPB) has been used for anesthesia in different settings such as in varicocelectomy and inguinal hernia repair in adults and pediatrics. Different studies considered LPB as an alternative to general and spinal anesthesia when contraindications exist, especially in elderly patients. However, the results obtained when using LPB are controversial in terms of number of injections performed and the success rates.

Detailed Description
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Patients scheduled for hernia repair who will agree to undergo different number of paravertebral injections in the thoraco-lumbar plexus area under CT guidance. While the patient is in lateral decubitis position, LPB injections will be made using a 100 mm 22 G nerve stimulator needle (Stimuplex, B.Braun, Melsungen, Germany). The site of injection is determined by manual palpation. The number of injections ranges from one to five and the level of injections ranges from T11 to L3. The needle is penetrated perpendicular to the skin using the following nerve stimulator settings: 5mA, 9V and 2Hz. The stimulating needle is gently manipulated into a position to allow an adequate muscular response with a stimulating current of 0.4-0.8 mA. At this point, 4-5 ml of the contrast (Telebrix 35, 350 mg/ml, Roissy CDG Cedex, France) is injected. The patients will receive the same amount of contrast, despite the different number of injections. The needles are kept in their position and afterwards followed by CT scan. A radiologist who is blind to the study will interpret the radiological results and document the level at which the needle tip is found, the distance from the kidney and the spread of the injected contrast. In order to ensure patient's safety, different measures will be taken to keep the radiation as low as reasonably achievable. Following the radiological practice, patients will be transferred to the operating room to undergo inguinal herniorrhaphy, and will not followed for the purpose of this study.

Official Title
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The Spread of Paravertebral Injections in the Lumbar Plexus Area and Associated Risk Factors to Adjacent Organs: a CT Scan Based Report

Conditions
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Lumbar Plexus Block

Intervention / Treatment
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* Other: Paravertebral injections
* Other: CT scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Older than 18 years Scheduled for hernia repair Exclusion Criteria: Patients with coagulation disorders, with infection at the injection site, with allergy to contrast receiving opioids

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Paravertebral injections<br>Lumbar paravertebral injections containing contrast will be performed. The needles are kept in their position and afterwards followed by CT scan. | Other: Paravertebral injections<br>* Paravertebral injections will be performed in the thoraco-lumbar plexus area under CT guidance<br>Other: CT scan<br>* CT scan will be performed as the needles are kept in their position after injecting the contrast<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Injection spread | Demonstrate spread of injected material in the lumbar plexus area according to different number of injections confirmed by CT guidance | 5 minutes after the procedure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Distance between injections and kidney | Measure the distance between the injections and kidney to assess safety of the procedure | 5 minutes after the procedure |