Chapter 80B: Interscalene Brachial Plexus Block

INTRODUCTION

The first brachial plexus blocks were performed by William Stewart Halsted, in 1885, at the Roosevelt Hospital in New York City. In 1902, George Washington Crile described an “open approach” to expose the (axillary) plexus facilitating direct application of cocaine. The need for surgical exposure of the brachial plexus led to limited clinical utility of this technique. This changed in the early 1900s when percutaneous access to the brachial plexus was first described. In 1925, July Etienne¹ reported the successful blockade of the brachial plexus by inserting a needle halfway between the lateral border of the sternocleidomastoid muscle and the anterior border of the trapezius muscle at the level of the cricothyroid membrane, making a single injection in the area around the scalene muscles. This approach was most likely the first clinically useful interscalene block technique. In 1970, Alon Winnie² described the first consistently effective and technically suitable percutaneous approach to the brachial plexus block. The technique involved palpating the interscalene groove at the level of the cricoid cartilage and injecting local anesthetic between the anterior and middle scalene muscles. Winnie’s approach was modified over the years to include slight variations to the technique such as perineural catheter placement.³ However, the success of this approach and the widespread adoption of the interscalene brachial plexus block as the “unilateral spinal anesthesia for the upper extremity,” should be credited solely to Alon Winnie.

More recently, the introduction of ultrasound-guided techniques has allowed for additional refinements and improved block consistency with reduced local anesthetic volumes (see Chapter 32B).^4,5,6

Indications

The interscalene block is indicated for procedures on the shoulder and proximal humerus as well as the lateral two thirds of the clavicle. The interscalene block can also be utilized for surgery of the arm or forearm; however, the higher incidence of incomplete blockade of the inferior trunk with this technique may provide inadequate analgesia in the ulnar distribution. The patient’s positioning and comfort, the surgeon’s preferences, and the duration of surgery may necessitate coadministration of a general anesthetic. An interscalene catheter may be inserted for prolonged postoperative analgesia (Table 80B–1).