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Brown: Atlas of Regional Anesthesia, 3rd ed., Copyright © 2006 Saunders, An Imprint of Elsevier
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Chapter 4 – Interscalene Block


Interscalene block (classic anterior approach) is especially effective for surgery of the shoulder or upper arm, as the roots of the brachial plexus are most easily blocked with this technique. There is frequently sparing of the ulnar nerve and its more peripheral distribution in the hand unless one makes a special effort to inject local anesthetic caudad to the site of the initial paresthesia. This block is ideal for reduction of a dislocated shoulder and often can be achieved with as little as 10 to 15 mL of local anesthetic. The block also can be performed with the arm in almost any position and thus can be useful when brachial plexus block needs to be repeated during a prolonged upper extremity procedure.

Patient Selection.

Interscalene block is applicable to nearly all patients, as even obese patients usually have identifiable scalene and vertebral body anatomy. However, interscalene block should be avoided in patients with significantly impaired pulmonary function. This point may be moot if one is planning to use a combined regional and general anesthetic technique, which allows control of ventilation intraoperatively. Even when a long-acting local anesthetic is chosen for the interscalene technique, usually phrenic nerve, and thus pulmonary, function has returned to a level that patients can tolerate by the time the average-length surgical procedure is completed.

Pharmacologic Choice.

Useful agents for interscalene block are primarily the amino amides. Lidocaine and mepivacaine produce 2 to 3 hours of surgical anesthesia without epinephrine and 3 to 5 hours when epinephrine is added. These drugs can be useful for less involved or outpatient surgical procedures. For more extensive surgical procedures requiring hospital admission, longer-acting agents such as bupivacaine or ropivacaine may be chosen. The more complex surgical procedures on the shoulder often require muscle relaxation; thus, bupivacaine concentrations of at least 0.5% are needed. Plain bupivacaine produces surgical anesthesia lasting 4 to 6 hours; the addition of epinephrine may prolong the anesthesia to 8 to 12 hours. The effects of ropivacaine are slightly shorter in duration.

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