Embolization Materials and Principles

Abstract

From the layperson’s perspective, the formation of an embolus is more associated with potentially fatal medical conditions, such as a myocardial infarction, stroke, or pulmonary embolism. Radiologist Dr. Sadek Hilal, however, conceptualized how an embolism that occluded a specific artery could actually possess therapeutic usage (Hilal and Michelsen, J Neurosurg 43:275-87, 1975). Hilal was not the first to consider the therapeutic potential of embolization, nor the first to put it into practice, but Hilal gained prominence for his paper detailing consistent usage of embolization to treat arteriovenous malformations and extra-axial vascular tumors in 27 patients (Hilal and Michelsen, J Neurosurg 43:275-87, 1975). Embolization remains a commonly used procedure that can be used to control vascular flow in a quick, minimally invasive manner. Embolization, the formation of an embolus (artificially or naturally), involves injecting an agent into a vessel to cause a mechanical occlusion and impaction and provide a framework for thrombosis. Most embolization agents require an intact coagulation cascade, so it is imperative that embolization is performed before severe coagulopathy develops. Embolization agents can be categorized into temporary and permanent agents. The selection of agent depends on the target for embolization, desired outcome, type of vessels, flow characteristics, and the potential for complications. Operators may use several maneuvers to avoid major complications such as agent reflux or distal embolization of nontarget organs.