Distance for Interscalene Block

University Health Network, Toronto25 enrolled

Overview

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.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Regional Anesthesia Inter Scalene Block Post Operative Analgesia

Eligibility

Sex: ALLMin age: 18 YearsMax age: 85 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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

Time frame: 20 mins

Secondary Outcomes

The onset time of sensory and motor block

Time frame: 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.

Time frame: 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.

Time frame: during the first 24 hours post operative

The amount of pain and level of satisfaction,

Time frame: every 30 minutes starting at post anesthesia care unit admission till 120 minutes

The presence of a Claude-Bernard-Horner Syndrome

Time frame: up to 24 hours post operative

The presence of hoarseness.