CT of Sacral Fractures: Classification Systems and Management.

CT is often performed as part of a whole-body protocol in the setting of polytrauma and is the standard of care for diagnosing and characterizing sacral fractures. These fractures are not uncommon, occurring in conjunction with pelvic ring disruption in approximately 40%-50% of patients. Knowledge of basic functional anatomy and fracture biomechanics is important in understanding sacral fracture patterns, which only rarely result from direct impact. More often, sacral fractures result from an indirect mechanism with fracture lines that propagate along relative lines of weakness, leading to predictable fracture patterns. Each fracture pattern has implications with respect to neurologic injury, spinopelvic stability, management, and potential complications. The authors explore the Denis, Roy-Camille, Isler, Robles, Sabiston-Wing, and shape-based classification systems for sacral fractures. These form the basis of the subsequently discussed unified AOSpine sacral fracture classification, a consensus system developed by spine and orthopedic surgeons as a means of improving and standardizing communication. The AOSpine sacral fracture classification also includes clinical designations for neurologic status and patient-specific modifiers. When a patient is unexaminable owing to obtundation or sedation, CT is an invaluable indirect marker of nerve compression or traction injury. It also plays an important role in visualizing and characterizing the type and extent of any associated soft-tissue injuries that may warrant a delay in surgery or an alternative operative approach.