Abstract and Introduction
Regional anesthesia has an established role in providing perioperative analgesia for shoulder surgery. However, phrenic nerve palsy is a significant complication that potentially limits the use of regional anesthesia, particularly in high-risk patients. The authors describe the anatomical, physiologic, and clinical principles relevant to phrenic nerve palsy in this context. They also present a comprehensive review of the strategies for reducing phrenic nerve palsy and its clinical impact while ensuring adequate analgesia for shoulder surgery. The most important of these include limiting local anesthetic dose and injection volume and performing the injection further away from the C5–C6 nerve roots. Targeting peripheral nerves supplying the shoulder, such as the suprascapular and axillary nerves, may be an effective alternative to brachial plexus blockade in selected patients. The optimal regional anesthetic approach in shoulder surgery should be tailored to individual patients based on comorbidities, type of surgery, and the principles described in this article.
Surgery for shoulder pathology is increasingly common,[1,2] with regional anesthesia playing an important role in multimodal analgesia for these painful procedures. Interscalene brachial plexus block is the most common regional anesthetic technique; however, phrenic nerve palsy and hemidiaphragmatic paresis have traditionally been inevitable consequences, which limit its utility in the population of patients at high risk of respiratory complications. A range of modifications and alternatives to interscalene block have been proposed to minimize the respiratory impact of phrenic nerve palsy, but to date there has been no thorough assessment of the clinical value offered by each of these strategies. In this article, we aim to describe the anatomical, physiologic, and clinical principles governing phrenic nerve palsy in the context of regional anesthesia for shoulder surgery. We also review the various techniques that seek to provide adequate regional anesthesia of the shoulder while minimizing the risk of phrenic nerve palsy, as well as methods for assessing their impact on diaphragmatic function, and thus provide a comprehensive narrative of their value in achieving these two objectives.
Anesthesiology. 2017;127(1):173-191. © 2017 American Society of Anesthesiologists | Lippincott Williams & Wilkins