Ultrasound-guided interscalene blocks.

nesthesiologists routinely use peripheral nerve blocks as an alternative or an adjunct to general anesthesia in addition to postoperative analgesia for a wide variety of procedures. More recently, emergency physicians have also begun using regional techniques in lieu of procedural sedation for a wide variety of extremity procedures such as reduction of shoulder dislocation.1 The goal of a peripheral nerve block is to apply a local anesthetic directly onto a peripheral nerve or nerve plexus to completely anesthetize the surgical site. Historically, anesthesiologists have performed peripheral nerve blocks using the paresthesia technique, in which the needle is inserted at a point determined by standard anatomic landmarks and then advanced until the patient feels paresthesia in the relevant sensory distribution.2 In the 1970s and 1980s, anesthesiologists began using a nerve stimulator to improve needle localization.3 Essentially, a nerve stimulator is a device that sends current through the block needle to elicit contraction of relevant muscle groups when in close proximity to the nerve of interest. These techniques are effective and are still in use, although they have many drawbacks. Over the past decade, ultrasound has gained popularity for peripheral nerve blockade because it allows the anesthesiologist to directly visualize the nerves of interest, the needle tip itself, and the spread of the local anesthetic in the desired location. In addition, the ultrasound image reliably depicts other structures such as blood vessels and lungs that the anesthesiologist wants to avoid. For these reasons, ultrasound guidance has increasingly become the standard technique for regional anesthesia.4 Brachial plexus blockade has long been used for upper extremity surgery, and there are several standard techniques. The interscalene block is especially useful for shoulder surgery. In this article, we will describe the technique of an ultrasound-guided interscalene block and then discuss its advantages over the traditional landmark technique.