Interscalene Block Versus Superior Trunk Block

Study Overview
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Brief Summary
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Sparing the phrenic nerve by administering ultrasound-guided low volume superior trunk block (STB) and interscalene block (ISB) for arthroscopic shoulder surgery (labral repair, stabilization, rotator cuff repair).

Official Title
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Interscalene Block Versus Superior Trunk Block: A Randomized Controlled Clinical Trial

Conditions
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Joint Disease, Pain, Pain, Acute, Pain, Chronic

Intervention / Treatment
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* Drug: Bupivacaine
* Device: Ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who will be undergoing primary unilateral labral repair/stabilization of the shoulder Age 18 to 80 years Planned use of general anesthesia with LMA and interscalene or superior trunk block Ability to follow study protocol English speaking ASA I - III Exclusion Criteria: Pre-existing neuropathy of the operative limb Younger than 18 years old and older than 80 Patients with pulmonary severe respiratory disease Allergy to one of the study medications Chronic gabapentin/pregabalin use (regular use for longer than 3 months) Chronic opioid use (taking opioids for longer than 3 months) Contraindication to general anesthesia, interscalene or superior trunk block Herniated Cervical Disk, Cervical Myelopathy BMI >35

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: interscalene block (ISB)<br>The interscalene block will be done using an ultrasound-guided, in-plane approach. The anesthesiologists will target below the C5 nerve root. A 22 gauge 1.5-2 inch needle is advanced in-plane from lateral to medial through the middle scalene muscle until the needle tip is positioned in the interscalene groove between the C5 and C6 nerve roots. 15 20 ml of 0.5% bupivacaine will be injected. | Drug: Bupivacaine<br>* Anesthetic that will help treat pain and sensation after shoulder arthroscopy<br>Device: Ultrasound<br>* Ultrasound will help guide the anesthesiologist in performing the different nerve blocks<br>|
| Experimental: superior trunk block (STB)<br>The superior trunk block will be performed at the point immediately distal to the roots when the c5-c6 form the superior trunk and lies anterior to the middle scalene muscle and below the deep cervical fascia, before the suprascapular nerve arises and goes into the omohyoid. A 22g 1.5-2inch needle will be advanced in-plane from lateral to medial. The needle tip will be placed lateral to the superior trunk and 15 20 ml of 0.5% bupivacaine will be injected just inferior to the deep cervical fasica. Local circumferential spread will be achieved both anterior and posterior to the superior trunk. | Drug: Bupivacaine<br>* Anesthetic that will help treat pain and sensation after shoulder arthroscopy<br>Device: Ultrasound<br>* Ultrasound will help guide the anesthesiologist in performing the different nerve blocks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Incidence of Hemidiaphragmatic Paralysis (HDP) | Our primary outcome will be the incidence of hemidiaphragmatic paralysis (HDP) with superior trunk block and interscalene blocks as measured by ultrasound before and after the surgery. | Day of Surgery, diagnosis confirmed from trained anesthesiologist ultrasound readers | 
| Numerical Pain Rating System (NRS) Pain Scores | Numerical Pain Rating System Pain scores after the superior trunk block and interscalene block at rest measured after the surgery every 30 minute until discharge according to the Post Anaesthetic Discharge Scoring System. Numerical Rating Scale 0-10; with 0 being no pain and 10 pain as bad as you can imagine. | Average pain scores at rest recorded Day of Surgery every 30 minutes until discharge according to Post Anaesthetic Discharge Scoring System | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Block Duration | Length of nerve block reported by Phone call on POD 1 and POD 2 by patient phone call | Time of block wearing off recorded on Post Operative Day 1 and Post Operative Day 2 as reported via patient phone call. |