The retroperitoneal space, also known as the retroperitoneum, is defined as the area between the parietal peritoneum and the muscles and bones of the posterior abdominal wall. Sandwiched between this thin tissue layer and the rigid back are solid organs, hollow viscera, and vascular structures.
Traumatic retroperitoneal hematoma is a potentially life-threatening condition associated with both blunt and penetrating injury mechanisms to the structures in that region.
Hematomas are divided into three zones based on their location in the retroperitoneum. Zone I is a centrally located hematoma of the upper retroperitoneum and is concerning for injury to the aorta, inferior vena cava, pancreas, or duodenum. Zone II, or the lateral zones, are on either side of zone I and include the kidney and its associated structures as well as parts of the colon. Zone III is located in the pelvis and often associated with blunt pelvic fractures or iliofemoral vascular injuries. Each zone presents unique challenges to diagnosis, as well as treatment. Treatment is divided into operative and nonoperative based upon mechanism of injury and the location of the hematoma. Mortality ranges widely based on location and etiology of the hematoma.
A stealth killer
To examine the occurrence of injured patients with retroperitoneal hematoma from a blunt mechanism contained in the National Trauma Data Bank® (NTDB®) research dataset admission year 2015, medical records were searched using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Specifically searched were records that included an external cause of injury code that represented a blunt trauma mechanism, along with a diagnosis code of 868.04 (injury to other intra-abdominal organs without mention of open wound into cavity, retroperitoneum).
A total of 4,583 records were found, of which 4,167 records contained a discharge status, including 1,981 patients discharged to home, 1,023 to acute care/rehab, and 560 to skilled nursing facilities; 603 died (see Figure 1). Of these patients, 70 percent were men, on average 48.3 years of age, had an average hospital length of stay of 10.6 days, an intensive care unit length of stay of 7.9 days, an average injury severity score of 24.5, and were on the ventilator for an average of eight days.
Figure 1. Hospital discharge status
Searching these records for the data field for comorbid condition number four (bleeding disorder) revealed that only 7 percent (331 of the 4,583) had a contributing factor, such as chronic anticoagulation, prior to sustaining an injury. Of those tested for alcohol, almost one-third (717 out of 2,471) tested positive.
With such a diverse presentation and potential constellation of associated injuries, it is no wonder that retroperitoneal hematomas left undiagnosed or undertreated can result in fatalities. Traumatic injuries often are visually obvious or easily diagnosed with routine studies in the trauma resuscitation area. However, given the location and occult nature of retroperitoneal hematomas, what you don’t see can kill you.
Throughout the year, we will be highlighting these data through brief monthly reports in the Bulletin. The NTDB Annual Report 2016 is available on the ACS website as a PDF file. In addition, information is available on our website about how to obtain NTDB data for more detailed study. If you are interested in submitting your trauma center’s data, contact Melanie L. Neal, Manager, NTDB, at firstname.lastname@example.org.
Statistical support for this article was provided by Chrystal Caden-Price, Data Analyst, NTDB.