Interscalene block in the era of ultrasound guided regional anesthesia

Abstract

Introduction: The introduction of ultrasound to regional anesthesia has redefined our understanding on this field; moreover, through ultrasound, regional anesthesia techniques have developed rapidly in response to more specific and complex needs. In this context, some changes and new concepts have raised around interscalene block. Objective: To revise recent advances as regards our knowledge of interscalene block since the ultrasound was introduced to regional anesthesia; as well as to evaluate different strategies to avoid hemidiaphragmatic paralysis. Material and Methods: A search was carried out in medical data bases (PubMed and Cochrane) and anesthesiology journals (Regional Anesthesia and Pain Medicine, Anesthesiology Journal, British Journal of Anesthesiology, among others). Search terms were as follows: interscalene block, hemidiaphragmatic paralysis, shoulders surgery, ultrasound guided interscalene block. Discussion: New concepts around interscalene block are quoted (traffic lighter sign-long thoracic and dorsal scapular nerve), as well as a short review about the respiratory compromise that follows this regional anesthesia technique and some strategies to avoid it. Conclusions: The introduction of ultrasound to regional anesthesia has redefined our understanding towards this field. It is mandatory for the regional anesthesiologist to comprehend these new concepts in order to provide a safe and effective regional anesthesia.