Article Text

Download PDFPDF
Case Report: Limitation of Local Anesthetic Spread During Ultrasound-Guided Interscalene Block. Description of an Anatomic Variant With Clinical Correlation
  1. Matthew S. Abrahams, M.D.a,*,
  2. Oliver Panzer, M.D.b,
  3. Arthur Atchabahian, M.D.b,
  4. Jean-Louis Horn, M.D.a and
  5. Anthony R. Brown, M.D.b
  1. aDepartment of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR
  2. bDepartment of Anesthesiology, Columbia University College of Physicians and Surgeons, New York, NY.
  3. *Reprint requests: Matthew S. Abrahams, M.D., OHSU Department of Anesthesiology and Perioperative Medicine, Mailcode UHS-2, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3011. E-mail: abrahama{at}


Objective: The use of ultrasound (US) for localization of neural structures allows real-time visualization of anatomy; however, variability in the arrangement of structures has been observed. The impact of these variations on the performance and outcome of regional anesthetic techniques remains unclear. We discuss possible anatomic explanations and correlation with clinical observations.

Case Report: We report limited spread of local anesthetic observed during the performance of a US-guided interscalene block. This was associated with an anomalous vessel arising from the subclavian artery, which effectively divided the brachial plexus into 2 compartments. Spread of local anesthetic was restricted to the upper compartment around the C5 through C7 nerve roots. There was no anesthetic fluid visualized in the lower compartment. This produced a block that provided surgical anesthesia for shoulder arthroscopy as well as excellent postoperative analgesia, although the medial and distal aspects of the arm remained unaffected.

Conclusions: This case illustrates the ability of US to identify anatomic variations and their relevance to the performance of regional anesthetic techniques.

  • Brachial plexus anatomy
  • Interscalene block
  • Ultrasound-guided regional anesthesia
  • Ulnar sparing

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • The authors received no outside funding for this work. This case report has not been presented at any meeting.