Comparison of Outside Versus Inside Brachial Plexus Sheath Injection for Ultrasound‐Guided Interscalene Nerve Blocks. (29th December 2015)

• Record Type: Journal Article
• Authors: Maga, Joni; Missair, Andres; Visan, Alex; Kaplan, Lee; Gutierrez, Juan F.; Jain, Annika R.; Gebhard, Ralf E.
• Is Part Of: Journal of ultrasound in medicine. Volume 35:Number 2(2016)
• Page Start: 279
• Page End: 285
• Publication Date: 2015-12-29
• Subjects: brachial plexus -- interscalene block -- neurosonology -- regional anesthesia; Ultrasonics in medicine -- Periodicals; Ultrasonics; Ultrasonography; Ultrasonics in medicine; Electronic journals; Periodicals; Periodicals; 616.07543
• DOI: 10.7863/ultra.15.01059
• Languages: English
• ISSNs: 0278-4297

Abstract

Abstract : Objectives: Ultrasound‐guided interscalene brachial plexus blocks are commonly used to provide anesthesia for the shoulder and proximal upper extremity. Some reviews identify a sheath that envelops the brachial plexus as a potential tissue plane target, and current editorials in the literature highlight the need to establish precise and reproducible injection targets under ultrasound guidance. We hypothesize that an injection of a local anesthetic inside the brachial plexus sheath during ultrasound‐guided interscalene nerve blocks will result in enhanced procedure success and provide a consistent tissue plane target for this approach with a reproducible and characteristic local anesthetic spread pattern. Methods: Sixty patients scheduled for shoulder surgery with a preoperative interscalene block for postoperative pain management were enrolled in this prospective randomized observer‐blinded study. Each patient was randomly assigned to receive a single‐shot interscalene block either inside or outside the brachial plexus sheath. Results: The rate of complete motor and sensory blocks of the axillary nerve territory 10 minutes after local anesthetic injection for the inside group was 70% versus 37% for the outside group ( P < .05). At all measurement intervals beyond 10 minutes, however, neither group showed a statistically significant difference in complete sensory blockade. The incidence rates of transient paresthesia during needle passage were 6.7% for the outside group and 96.7% for the inside group ( P < .05). Conclusions: Except for faster onset, this prospective randomized trial did not find any advantages to performing an interscalene block inside the brachial plexus sheath. There was a higher incidence of transient paresthesia when injections were performed inside compared to outside the sheath.