interscalene nerve block complication

An interscalene nerve block anesthetizes most of the territory innervated by the brachial plexus and is generally performed on patients undergoing shoulder, upper arm, or elbow surgery. Landmarks used to perform this procedure include the interscalene groove, which is found between the middle and anterior scalene muscles at the level of the sixth cervical vertebra, which is approximately at the level of the cricoid cartilage.

Nerves anesthetized during this procedure include most of the brachial plexus, sparing the ulnar (C8-T1) nerve. In addition, the phrenic nerve is often anesthetized during this procedure, resulting in ipsilateral hemidiaphragmatic paralysis. Therefore, patients with underlying respiratory conditions (e.g. COPD) should not undergo this procedure. In addition, the recurrent laryngeal nerve is often anesthetized--resulting in temporary paralysis of the ipsilateral vocal fold. Additional complications include iatrogenic pneumothorax, as well as hematoma/seroma formation.