Long-Term Incidence and Timing of Splenic Pseudoaneurysm Formation after Blunt Splenic Injury: A Descriptive Study

Nonoperative management (NOM) has become a standard strategy for hemodynamically stable patients with blunt splenic injury; however, delayed rupture of splenic pseudoaneurysm (SPA) is a serious complication of NOM. In medical literature, data regarding the long-term incidence of SPA are scarce, and the appropriate timing for performing follow-up contrast-enhanced computed tomography (CT) has not yet been reported. This study aimed to elucidate the long-term incidence and timing of SPA formation after blunt splenic injury in patients treated with NOM. This descriptive study was conducted at a tertiary medical center in Japan. Patients with blunt splenic injury who were treated with NOM between April 2014 and August 2020 were included in the analysis. Included patients underwent repeated contrast-enhanced CT to detect SPA formation. The primary outcome was the cumulative incidence of delayed formation of SPA. We also evaluated differences in SPA formation between patients who received transcatheter arterial embolization (TAE; TAE group) and those who did not receive it (non-TAE group) on admission day. Among 49 patients with blunt splenic injury who were treated with NOM, 5 patients (10.2%) had delayed formation of SPA. All cases of SPA formation occurred within 15 days of injury. The incidence of SPA formation was not significantly different between the TAE and non-TAE groups (1/19 vs. 4/30, P = 0.67). SPA developed in 10% of patients within approximately 2 weeks after blunt splenic injury. Therefore, performing follow-up contrast-enhanced CT in this period after injury may be useful to evaluate delayed formation of SPA. Although our findings are novel, they should be confirmed through future studies with larger sample sizes.