Table 2.

Summary table of key studies on splenic embolization with a level of evidence designation. Levels of evidence are defined using the grading system adapted from the American Society of Plastic Surgeons and Johns Hopkins nursing evidence-based practice: Models and Guidelines (Burns et al. 2011; Dang and Dearholt 2017) - (see Table 5)

Title, Author Year	Number of Patients	Study Design	Key Point(s), Data, Summary	Level of Evidence
Splenic trauma: WSES classification and guidelines for adult and pediatric patients (Coccolini et al. 2017).	NA	Review	Surgical management guidelines for splenic trauma including AAST classification and recommendations for the use of non-operative treatments. Recommendations include: Consideration of angiography and/or embolization in stable patients with AAST grade I-III splenic injury. Angiography and embolization for stable AAST grade IV-V splenic injuries.	IV
Trauma center variation in splenic artery embolization and spleen salvage: a multicenter analysis (Banerjee et al. 2013).	1275	Multicenter Meta-analysis	Centers with high use of splenic artery embolization have higher spleen salvage rates and fewer nonoperative management failures.	I
Nonoperative management of adult blunt splenic injury with and without splenic artery embolotherapy: a meta-analysis (Requarth et al. 2011).	10,157	Meta-analysis	Summarizes outcomes for patients with splenic injuries with non operative management. They found a higher failure rates in patients managed with observation alone compared with splenic artery embolization. Splenic artery embolization patients also showed significantly higher splenic salvage rates in grade 4 and 5 splenic injuries.	I
Transcatheter arterial embolization of splenic artery aneurysms and pseudoaneurysms: short- and long-term results (Loffroy et al. 2008)	17	Retrospective	Compared outcomes of endovascular treatment of splenic artery aneurysms and pseudoaneurysms. They found no major complications, and concluded embolization of splenic artery aneurysms and pseudoaneurysms is a safe and effective method of splenic preservation.	II
The anatomy of the fundic branches of the stomach: preliminary results (Gregorczyk et al. 2008).	NA	Descriptive laboratory study	Provides an anatomic description of the arterial vascularisation of the gastric fundus in 15 human specimens.	V
Outcomes of Proximal Versus Distal Splenic Artery Embolization After Trauma: A Systematic Review and Meta-Analysis (Schnuriger et al. 2011).	479	Meta-Analysis	Analyzes 15 studies regarding the use of both proximal and distal embolization in patients with splenic trauma. Summary of outcomes and complications for proximal vs distal splenic embolization.	I
Evaluation of the Amplatzer vascular plug for proximal splenic artery embolization (Widlus et al. 2008).	14	Retrospective	In these preliminary studies, Amplatzer vascular plugs were used successfully for proximal splenic artery embolization without any major complications.	II
Delayed presentation of splenic artery pseudoaneurysms following blunt abdominal trauma (Nance and Nance 1995).	2	Case report	Two patients with delayed presentation of splenic artery pseudoaneurysm following blunt abdominal trauma. Both vascular injuries were diagnosed on a follow up CT scan, highlighting the need for follow up imaging in patients with blunt abdominal trauma.	V
The impacts of different embolization techniques on splenic artery embolization for blunt splenic injury: a systematic review and meta-analysis (Rong et al. 2017).	876	Meta-Analysis	Comparison of PSAE vs distal embolization, and PSAE vs PSAE + distal embolization. Reports rates of success and severe complication. Lowest complications with PSAE, highest with combined proximal and distal embolization.	I
Conservation of the spleen with distal pancreatectomy (Warshaw 1988)	NA	Clinical examples, expert opinion	Authors describe their experience with preservation splenic vascular collateral pathways via the short gastric and gastroepiploic vessels during a distal pancreatectomy.	V
Laparoscopic spleen-preserving distal pancreatectomy: splenic vessel preservation compared with the Warshaw technique (Jean-Philippe et al. 2013).	140	Retrospective	Discusses collateral arterial pathways for splenic circulation, which are essential to splenic preservation following proximal splenic artery embolization.	II
Proximal splenic artery embolization for blunt splenic injury: clinical, immunologic, and ultrasound-Doppler follow-up (Bessoud et al. 2007).	37	Retrospective	Proximal splenic artery embolization for the treatment of splenic injury in blunt abdominal trauma is safe and preserves long term splenic function.	II
Splenic embolization revisited: a multicenter review (Haan et al. 2004).	140	Retrospective	Rebleeding following splenic embolization can occur in up to 24% of patients, but this is often treated successfully with re-embolization. Distal embolization often causes small splenic infarcts.	II
Non-operative management of blunt splenic injury: a 5-year experience (Haan et al. 2005).	109	Retrospective	Single center study showing hemodynamically stable patients with grade III – V splenic lacerations treated with PSAE have a higher likelihood of splenic salvage compared with those treated with observation alone.	II