CT characteristics of traumatic sacral fractures in association with pelvic ring injuries: correlation using the Young-Burgess classification system.

PURPOSE: The purpose of the study is to determine the incidence of sacral fracture patterns on CT imaging of pelvic trauma patients with correlation with mechanism of injury and pelvic ring injury pattern using the Young-Burgess classification system.

MATERIALS AND METHODS: This is a retrospective review of all pelvic CTs with pelvic fractures performed at our level 1 trauma center during a 4-year period from July 2010 to June 2014.

RESULTS: Sacral fractures were very common in pelvic trauma patients, being present in 60% of patients presenting to our institution with pelvic fractures. Longitudinal fractures were almost always associated with additional pelvic ring injuries. Denis zone 1 fractures had the highest association with lateral compression pelvic ring injuries. Denis zone 2 and 3 fractures were seen with increased frequency in AP compression and vertical shear injuries. A third of transverse sacral fractures occurred in isolation, with isolated transverse sacral fractures typically occurring in the low (S3-S5) sacrum. Almost half of combined transverse and longitudinal sacral fractures occurred without an additional pelvic fracture present. Sacral avulsions almost always occurred as part of a pelvic ring fracture pattern, most commonly in AP compression injuries. Coccyx fractures frequently occurred in isolation, but were commonly seen in vertical shear injuries when associated with a pelvic ring injury pattern.

CONCLUSION: Avulsion fractures and longitudinal fractures of the sacrum are almost always associated with anterior pelvic ring injury. Conversely, transverse fractures of the lower sacrum and combined longitudinal and transverse sacral fractures are prone to occur in isolation.