Utility of Intrapleural Contrast in the Diagnosis of Occult Diaphragmatic Injury in Thoracoabdominal Stab Wounds, Preliminary Results

"nIntroduction: Given the small size of the diaphragmatic defect and absence of visceral herniation, diagnosing diaphragmatic injury in the setting of thoracoabdominal stab wounds is challenging. CT scan with or without IV and oral contrast has been investigated with various efficacy previously. To our knowledge utility of intrapleural water soluble contrast has never been investigated before in the detection of diaphragmatic injury. "nMaterial and Method: 27 patients with thoracostomy tubes inserted for routine indications with thoracoabdominal stab wounds were included in the study. 500cc diluted contrast was administered via the patients' thoracostomy tube. CT and fluoroscopy were carried out. Images were evaluated by two radiologists prospectively and differences settled by consensus. All patients underwent thoracoscopic evaluation of the diaphragm. The diagnostic accuracy was calculated. "nResults: CT scan correctly predicted 21 of the 24 patients with an intact diaphragm. 4 patients showed some form of diaphragmatic injury, only one needed repair. CT scan correctly detected the injury needing repair. One case had an abrasion, one case had a 1.5cm flap with an intact peritoneum and one case had a 1.0cm tear in the right diaphragmatic dome. Negative predictive value in detecting defects needing surgical repair was 100%. Two false positive cases were present. No adverse effects were seen. "nConclusion: Intrapleural contrast administration is a safe and reliable way to rule out diaphragmatic injuries.