Delayed formation of splenic pseudoaneurysm following nonoperative management in blunt splenic injury: multi-institutional study in Osaka, Japan

Delayed rupture is well-known as a severe complication after splenic injury treated with nonoperative management (NOM). The incidence and timing of splenic pseudoaneurysm (SPA) formation, which is a cause of delayed rupture following splenic injury, have not been thoroughly investigated, and the timing of follow-up computed tomography (CT) is controversial. The objective of this study was to clarify the incidence and timing of both the delayed formation and spontaneous resolution of SPA following splenic injuries treated with NOM in several trauma centers in Japan. This was a retrospective review of all patients with documented blunt splenic injury who were treated with NOM from 2003 through 2010 in five trauma and critical care centers. The present study consisted of 104 patients, including 16 patients (15.4%) with delayed formation of SPA (7 patients with Grade II and 9 with Grade III) during their clinical course. SPA was diagnosed with enhanced CT at a mean (SD) of 4.6 (2.1) hospital days (range, 1-8 days) after admission. Delayed formation of SPA was found in 30.4% of Grade II injuries and in 18.4% of Grade III injuries. Eight patients with delayed formation of SPA were observed without transcatheter arterial embolization during their entire stay. These SPAs were spontaneously occluded on follow-up enhanced CT or angiography. Spontaneous occlusion of SPA was confirmed at 5.2 (2.6) hospital days (range, 2-10 days) after diagnosis of delayed SPA. Delayed formation of SPAs was recognized with enhanced helical CT in 15% of all patients during hospital Days 1 to 8. About one half of the SPAs had occluded spontaneously without therapeutic intervention. Our results suggested that follow-up enhanced CT performed approximately 1 week after splenic injury may be useful to detect delayed SPA formation. Epidemiologic study, level III.