Traumatic injuries: imaging and intervention in post-traumatic complications (delayed intervention).

The nonoperative management (NOM) of abdominal trauma has gained increasing acceptance over the past decade. This approach has been extended to severe trauma patients previously considered as candidates for surgery. Consequently, the incidence of delayed and uncommonly encountered complications has increased. Causes of delayed complications are multiple and include: (a) abnormal or insufficient injury healing process; (b) retention of necrotic tissue; (c) secondary infection of initially sterile collections; and (d) underestimation of injury severity. The purpose of this review article is to explain the role of various imaging modalities in detecting post-traumatic delayed complications and to highlight the usefulness of minimally invasive techniques, including laparoscopy, biliary endoscopy, therapeutic angiography and image-guided drainage. Subsequent complications, which do not necessarily negatively influence the final outcome, are often predictable, virtually obligatory consequences of the successful NOM of high-grade or complex abdominal injuries. Between 50 and 60% of those patients with grade-IV or grade-V liver or splenic lacerations require some type of interventional treatment; therefore, indiscriminate discharge of patients with solid organ injury managed conservatively may be potentially harmful. As the incidence of complications is higher for more severe grade-IV or grade-V liver, spleen, or kidney injuries, scheduled follow-up CT scans may be rational in this subset of patients to identify potential complications amenable to early application of interventional techniques. Follow-up CT scans are unnecessary in stable adults or children with low-grade injury. Delayed splenic or hepatic rupture is one of the major concerns because this type of complication remains difficult to predict and historically often requires emergent surgery. These ruptures may benefit from NOM, should the same criteria as for primary rupture be respected. Conversely, parenchymatous focal pooling of contrast on initial CT is a good predictor for the development of delayed vascular malformation. In children, as a large part of splenic and hepatic vascular malformations resolve spontaneously, expectant observation may be indicated provided that a strict imaging follow-up is performed until complete disappearance of these lesions. If needed, embolization of parenchymal vascular lesions should be performed as selectively as possible in order to avoid functional parenchyma loss and to reduce the risk of secondary infection of hematoma or ischemic tissue. Technical improvements, such as microcatheter systems and direct percutaneous approach to targeted lesions, have widened the potential for safe endovascular management of acquired vascular malformations. Advantages and disadvantages relative to the different embolic agents are explained. Endoscopic retrograde pancreatography is the chief investigational tool for detecting biliary and pancreatic ducts injuries. The respective roles of endoscopic, percutaneous and surgical approaches in the management of these complications are discussed. The CT scan and ultrasound-guided drainage provide effective nonoperative options in the management of post-traumatic parenchymatous and (retro)-peritoneal collections. Treatment modalities of less common complications, such as bowel stricture or perforation, mesenteric vascular injuries and renal trauma-induced hypertension, are reviewed.