Optimal Location of Local Anesthetic Injection for Ultrasound Guided Interscalene Block

Study Overview
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Brief Summary
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This is a prospective randomized clinical trial to determine where is the optimal location for local anesthetic injection for ultrasound guided interscalene nerve blocks. The investigators are investigating if local anesthetic deposited between the nerve roots is more effective than local anesthetic deposited in the interscalene groove.

Official Title
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Intraplexus vs Extraplexus Injection of Local Anesthetic for Interscalene Block for Patients Undergoing Arthroscopic Shoulder Surgery

Conditions
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Shoulder Arthroscopy, Ultrasound-guided Interscalene Nerve Block

Intervention / Treatment
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* Procedure: Interscalene block for shoulder arthroscopy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I-II patients who are 18 years and older and who are scheduled for shoulder arthroscopy are eligible for enrollment provided they do not have any of the following exclusion criteria. Exclusion Criteria: chronic pain high preoperative opioid requirement age < 18 years old non-English speaking contraindication to regional anesthesia (allergy to local anesthetics, coagulopathy, severe thrombocytopenia, pre-existing neuropathy in operative limb, infection at puncture site) need for postoperative nerve function monitoring patient refusal dementia pulmonary disease or low baseline oxygen saturation

Ages Eligible for Study
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Minimum Age: 18 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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Injection in interscalene groove<br>Patients undergoing shoulder arthroscopy will have an interscalene nerve block by injection of ropivacaine in the interscalene groove anterior and posterior to the brachial plexus nerves. | Procedure: Interscalene block for shoulder arthroscopy<br> <br> |
| Active Comparator: Injection between nerve roots<br>Patients undergoing shoulder arthroscopy will have an interscalene nerve block by injection of ropivacaine in the interscalene groove inbetween the C5 and C6 nerve roots. | Procedure: Interscalene block for shoulder arthroscopy<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Onset of motor blockade | Time to loss of shoulder abduction. | 1 hour from time of injection | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient Satisfaction Score |  | 24 hours | 
| Opioid consumption | Opioid consumption - perioperative and post discharge | 24 hours | 
| Quality of Nerve block | onset of sensory block | 24 hours | 
| Incidence of post-operative nausea/vomiting |  | 24 hours | 
| Duration of nerve block | Duration of analgesia from nerve block | 24 hours | 
| Number of needle passes |  | 1 hour | 
| Number of paresthesias | number of paresthesia experience during nerve block | 1 hour | 
| Residual paresthesia | incidence of residual paresthesias | 24 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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shoulder arthroscopy, ultrasound guided nerve block, interscalene nerve block