Ultrasound-guided modified out of plane infraclavicular approach

Document Type

Conference Proceeding

Publication Date


Publication Title

Regional Anesthesia and Pain Medicine


Results/Case report The Infraclavicular Block (ICB) is a common approach to the brachial plexus to provide anesthesia and analgesia to the arm below the level of the mid-humerus. As compared to the supraclavicular brachial plexus block, the ICB has several advantages, which include a decreased risk of phrenic nerve palsy (1) and an increased likelihood of effectively blocking the intercostobrachial nerve (2). The incidence of pneumothorax is not increased with and ultrasound guided ICB as compared to an ultrasound guided supraclavicular block (3). Several techniques for ultrasound guided ICB are described in the literature; however, these approaches are technically challenging in patients with morbid obesity and/or the inability to abduct the arm. We describe two morbidly obese patients in whom we successfully performed a modified out of plane infraclavicular approach (MOPIA) to the brachial plexus. The first patient is a 77 year old obese (BMI 32) woman with end stage renal disease, COPD on home oxygen, and significant glenohumeral joint arthritis that limited shoulder range of motion. She was scheduled for the creation of an AV fistula on her left forearm. The second patient is a 79 year old obese (BMI 35) man with end stage renal disease who was scheduled for an AV fistula ligation and creation of a new AV fistula on his left arm. The obesity of these patients hindered the ability of the high frequency linear probe to adequately visualize the brachial plexus. The first patient's range of motion limitation further impaired efforts for optimal positioning and visualization of the brachial plexus. The MOPIA technique was carried out in both patients with the anesthesiologist standing on the contralateral side of the brachial plexus to be blocked. An insulated stimulating needle was used in an out-of-plane approach using the curvilinear low frequency probe for needle tip and target visualization. The axillary artery and the surrounding brachial plexus were located by placing the probe slightly medial and caudal to the coracoid process. Approximately 25-35 mL of 1.5% mepivacaine was injected at three locations (6 o'clock, 9 o'clock, and 3 o'clock) around the axillary artery to achieve complete nerve blockade. No complications occurred during or after the block procedure, and surgery proceeded uneventfully. Two common approaches to ICB are the medial infraclavicular technique (2) and the costoclavicular technique (4). Both of these techniques require an abducted arm for optimal visualization. A retoclavicular technique is used with an adducted arm; however, obesity and a short neck can hinder visualization (5). It is our opinion that the modified out of plane infraclavicular approach would serve as a viable, safe, and efficient technique for dealing with non-traditional candidates for an infraclavicular block.





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