Predicting urethral injury from pelvic fracture patterns in male patients with blunt trauma.

PURPOSE Precise definition of pelvic fracture location may enable prediction of which subjects are at risk for urethral injury and understanding of the pathophysiological mechanism of injury. We determined the specific anterior pelvic injury locations associated with urethral injury. MATERIALS AND METHODS We completed a retrospective, nested case-control study of 119 male patients evaluated at a single large level 1 trauma center between January 1, 1997 and July 15, 2003. We performed detailed measurements of the location, displacement and direction of force of each anterior pelvic fracture from computerized tomography and pelvic radiographs. Multiple logistic regression was used to determine associations between specific fracture locations and urethral injury after controlling for age, injury mechanism, injury severity and direction of force. RESULTS Urethral injury was present in 25 patients and all had anterior pelvic fracture (inclusive of pubic symphysis diastasis). There were no urethral injuries in patients with fractures isolated to the acetabulum. Pelvic fractures that were independently associated with urethral injury from multiple regression analysis included displaced fractures of the inferomedial pubic bone, OR 6.4 (95% CI 1.6 to 24.9), and symphysis pubis diastasis, OR 11.8 (95% CI 4.0 to 34.5). Each millimeter of symphysis pubis diastasis or inferomedial pubic bone fracture displacement was associated with an approximately 10% increased risk of urethral injury. CONCLUSIONS The location and displacement of anterior pelvic fractures in males predict risk of urethral injury and may be valuable in determining when evaluation of the urethra is appropriate.