Out of Plane Approach for Interscalene

Studies have proven that there is 100% blockade of the phrenic nerve with the in-plane approach to the interscalene brachial plexus block. The patient population with pulmonary comorbidities with poor reserve cannot afford to have a further deterioration of their pulmonary status due to phrenic nerve blockade. These patients are not ideal candidates for increased opiate therapy for intraoperative and post-surgical pain as well due to further depression of their respiratory function. To optimize their pain control as well as avoid any respiratory-related morbidity and mortality, it is ideal to develop a technique which can provide appropriate brachial plexus block at the interscalene level while completely avoiding any local anesthetic spread to the phrenic nerve. The study aims to examine the influence of out of plane interscalene approach to a brachial plexus block on the effect of phrenic nerve blockade. Practitioner preference and institutional norms often influence the in plane approach for the above-mentioned block. The most common practice at our institution is the in plane approach to the brachial plexus block.