Diaphragm-sparing nerve blocks for shoulder surgery: essentials of our current understanding.

Shoulder surgery for patients with pulmonary disease constitutes a unique dilemma. Over the last 10 years, multiple randomized trials have investigated diaphragm-sparing alternatives to interscalene brachial plexus block. In this Education Article, we review the essentials of our current understanding by discussing the innervation of the shoulder, definitions of hemidiaphragmatic paralysis, and the evidence supporting the different diaphragm-sparing nerve blocks. For each diaphragm-sparing strategy, we also identify remaining knowledge gaps and areas requiring further investigation.