A Cadaver Study Investigating Structures Encountered by the Needle During a Retroclavicular Approach to Infraclavicular Brachial Plexus Block

Background and Objectives Retroclavicular block is designed to overcome the negative aspects of the commonly utilized ultrasound-guided parasagittal approach to the infraclavicular block. However, this approach necessitates the needle traversing an area posterior to the clavicle inaccessible to ultrasound wave conduction. This study sought to document the structures vulnerable to needle injury during a retroclavicular block. Methods A Tuohy needle was inserted using a retroclavicular approach to the infraclavicular block in 3 lightly embalmed cadavers followed by a catheter insertion 4 cm beyond the needle tip. The process was repeated on the contralateral side. With the needle and catheter in position, the cadavers were dissected and photographed. Results In 4 of the 6 dissections, the needle was directly touching the suprascapular nerve deep to the clavicle. In the remaining 2 dissections, the suprascapular nerve was within 2 cm of the needle. In 1 dissection, the suprascapular vein was indented, behind the clavicle. The trapezius was the only muscle layer traversed by the needle in all dissections. In 3 of the 6 dissections, the catheter penetrated the posterior cord. In the remaining 3, the catheter threaded along the neurovascular bundle. Conclusions The suprascapular nerve is consistently in the path of the block needle posterior to the clavicle. This raises the possibility of risk of injury to the suprascapular nerve when using this approach to the brachial plexus. Vascular injury is also possible deep to the clavicle, and because of the noncompressible location, caution is advised in patients with disordered coagulation. Accepted for publication March 10, 2018. S.F.S. is now with the Department of Anesthesiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. Address correspondence to: Vishal Uppal, DA, EDRA, FRCA, Department of Anesthesia, Perioperative Medicine and Pain Management, Dalhousie University, Nova Scotia Health Authority and IWK Health Centre, Halifax, Nova Scotia, Canada B3H 2Y9 (e-mail: v.uppal@dal.ca). No external funds were obtained for the study. Internal departmental funds were used. V.U. has been a principal investigator for a Recro Pharma (Devault, PA)–funded clinical trial involving intravenous meloxicam in Halifax, Nova Scotia, Canada. This conflict does not directly or indirectly affect the conduct or reporting of this study. The authors declare no conflict of interest. Author contributions: Study design/planning: all authors; study conduct: S.F.S., V.U., R.S.; writing of the paper: S.F.S., V.U; revision of the manuscript: all authors. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.rapm.org). Copyright © 2018 by American Society of Regional Anesthesia and Pain Medicine.

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