Costal Margin Tenderness and the Risk for Intraabdominal Injuries in Children With Blunt Abdominal Trauma.

BACKGROUND: The risk of radiation exposure from computed tomography (CT) imaging in children is well recognized. Patient history and physical examination findings, including costal margin tenderness (CMT), influence a physician's decision to image a child with blunt torso trauma. The objective of this study was to determine the importance of CMT for identifying children with intraabdominal injuries (IAI) found on CT and IAI undergoing acute intervention.

METHODS: We conducted an analysis of the Pediatric Emergency Care Applied Research Network (PECARN) IAI public use data set, representing a large prospective multicenter cohort study from May 2007 to January 2010. Isolated CMT was defined as CMT without other identified PECARN risk factors for IAI (i.e., abdominal or thoracic wall trauma, abdominal tenderness or pain, decreased breath sounds, or vomiting). Logistic regression was used to calculate adjusted odds of IAI in children presenting with isolated and nonisolated CMT. Risk differences were calculated to estimate the risk of IAI independently attributable to CMT in the setting of isolated PECARN risk factors. Finally, CT use among exposure groups was estimated to quantify potentially avoidable imaging.

RESULTS: Among 9,174 children with Glasgow Coma Scale scores of 14 or 15 who sustained blunt torso trauma, 1,267 (13.8%) had CMT. Among those with CMT, 177 (14.0%) had isolated CMT and 1,090 (86.0%) had nonisolated CMT. No children (0/177; 0%, 95% confidence interval [CI] = 0.0%-2.1%) with isolated CMT had IAI, compared to 17.2% (187/1,090; 95% CI = 15.0%-19.5%) of those with nonisolated CMT. The risk differences were not statistically significant. 36/177 (20.3%; 95% CI = 14.7%-27.0%) children with isolated CMT underwent abdominal CT scans.

CONCLUSIONS: The risk of IAI associated with isolated CMT is minimal. For children with blunt abdominal trauma and isolated CMT, abdominal CT scan is of low yield.