Distance for Interscalene Block

Study Overview
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Brief Summary
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Patients experience significant postoperative pain following shoulder surgery, Single shot interscalene block is used in ambulatory shoulder surgery for its advantages that include significant reduction in acute pain and analgesic requirements, prolonged time to first analgesic request, decreased incidence of nausea, as well as earlier hospital discharge.The process of nerve block requires several needle passes, with each of them being at risk of causing nerve injury either by direct trauma or intraneural injection even with the use of the ultrasound. These facts raised concerns and several authors stated that maybe the anesthesiologists should be more careful, keep a safe distance from the nerve, and inject the local anesthetics into fascial planes containing the nerve and not attempt to place the needle in close proximity to the nerve. This study is designed to determine the maximal effective distance away from the nerve for the injection to be effective.

Official Title
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What is the Maximal Effective Distance for Interscalene Block?

Conditions
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Regional Anesthesia, Inter Scalene Block, Post Operative Analgesia

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA physical status I-III 18-85 years of age, inclusive surgery less than 3 hours Exclusion Criteria: contraindications to brachial plexus block (e.g., allergy to local anesthetics, coagulopathy, malignancy or infection in the area) existing neurological deficit in the area to be blocked pregnancy history of neck surgery or radiotherapy severe respiratory disease inability to understand the informed consent and demands of the study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Success of the inter-scalene block at 20 minutes after injection at a specific distance of the needle tip from the outer sheeth of the nerve |  | 20 mins | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The onset time of sensory and motor block |  | the block success will be assessed for each patient every 5 min for 20 mins in the block room beginning when the needle exits the skin | 
| The proportion of inadequate and failed blocks. |  | the block success will be assessed for each patient every 5 min for 20 mins in the block room beginning when the needle exits the skin | 
| The duration of block, defined as the time from the completion of block performance to the time of the request for the first postoperative analgesic. |  | during the first 24 hours post operative | 
| The amount of pain and level of satisfaction, |  | every 30 minutes starting at post anesthesia care unit admission till 120 minutes | 
| The presence of a Claude-Bernard-Horner Syndrome |  | up to 24 hours post operative | 
| The presence of hoarseness. |  | up to 24 hours post operative | 
| The presence of other complications such as hematoma, infection, pneumothorax. |  | up to 24 hours post operative and 7 days post op | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inter-scalene Block, Regional Anesthesia, shoulder surgeries