This multi-institutional study demonstrates that the LOBO device is potentially safe and effective option for proximal splenic artery embolization, achieving 100% technical and clinical success, while significantly reduced number of devices used, fluoroscopy time and radiation dose compared with coils.

The selection of embolic agents remains crucial for achieving successful outcomes in the management of splenic injuries. This decision is based on various patient factors, including vessel anatomy, injury type, and embolization site. Coils, temporary embolic agents, vascular plugs, and liquid embolic agents each have their strengths and limitations with each use case in SAE [10,11,12,13,14]. Coils are commonly utilized in SAE. Technical success of coils has been shown to range from 88 to 100%, while the clinical failure rates vary between 12.1 and 27% [15]. They can be deployed through large and small French size catheters based on the vessel size and can be either pushable or detachable. Most often, multiple coils are required to occlude larger high-flow arteries like the splenic artery [7]. A meta-analysis by Johnson et al. showed that an average of 3.54 coils was used per SAE, which is in concordance with our study, where a mean of 4.6 coils was utilized per SAE [7]. Coils along with the temporary embolic agent such as gelfoam have shown varying primary clinical success ranging between 73 and 92.9% across various studies [15]. Coil migration is one of the complications associated with coil embolization, especially in a high-flow system such as the splenic artery; with reported coil migration rate of 31.8% [16]. In the present study, LOBO achieved complete occlusion with a single device and was associated with reductions in both fluoroscopy time and radiation dose, including a mean fluoroscopy time difference of 7.32 min (p = 0.012) and a median radiation dose difference of 70.1 mGy, supporting its procedural efficiency compared with coil embolization (Fig. 1). It is worth noting that two patients in both groups underwent tandem embolization of the distal splenic artery based on angiographic findings; therefore, it is unlikely to have skewed results for a particular cohort. Finally, radiation dose is influenced by multiple factors related to procedural complexity and cannot be attributed solely to device choice.

Vascular plugs are an effective alternative to coils for proximal SAE. A meta-analysis comparing the Amplatzer vascular plug (AVPs) (St. Jude Medical, Inc., St. Paul, MN, USA), with coils showed on average, in the AVP group, 4.43 devices (additional AVPs or coils) were required per procedure compared to 9.97 coils, with a shorter procedure time (55.6 min vs 45.82 min). The reported technical success rate for AVP in proximal SAE ranges from 87 to 100% and clinical success (splenic salvage) from 98 to 100% [17]. However, multiple embolic devices AVPs are often necessary for complete occlusion, and deployment can be challenging in tortuous vessels due to the device’s relative stiffness and stainless-steel core [6, 16, 18]. In comparison, all the LOBO procedures in this study only required a single device without the need for any additional embolic. Similar to devices such as the AVPs, the LOBO device does not produce significant imaging artifacts as compared to coils, especially on CT, which is another advantage, especially when analyzing follow-up imaging [19].

Micro vascular plugs (MVPs) are another routinely utilized device in arterial embolization. Their lower recanalization rates and ease of deployment compared with other metallic embolic devices, such as coils and AVPs, have made them a suitable choice for embolization in certain situations. In a multicenter retrospective study by Giurazza et al. evaluating the efficacy of MVP in the management of arterial hemorrhage, an overall technical success rate of 75% and a primary clinical success rate of 96.1% were reported [20]. Furthermore, a study by Mailli et al. showed the need for reinforcement with additional devices in 20 of 30 patients treated for arterial hemorrhage treated with MVP [21]. Therefore, both aforementioned studies demonstrate that a significant proportion of patients require additional embolic devices to achieve complete occlusion when using MVP for the management of arterial hemorrhage.

Splenic infarction and abscess formation remain key concerns following SAE. Few studies have criticized distal SAE for splenic abscess formation and splenic infarcts [15, 22]. A retrospective study of 72 patients showed that combined proximal and distal embolization was associated with a higher rate of splenic abscess and splenic infarction than either proximal or distal embolization [23]. A retrospective study demonstrated that proximal embolization was associated with significantly lower rates of major complications, including rebleeding, infarction, abscess formation, and contrast-induced nephropathy occurring in 10.7% of patients compared with 30.7% following distal embolization [24]. In this study, splenic infarction occurred in 33.3% of the coil group and 22.7% of the LOBO group. However, splenic infarction may reflect both the embolization approach and the underlying traumatic injury itself. Notably, the rates observed in our study were higher than those reported in more recent literature across different embolics [17].

There are key limitations associated with the study, including the retrospective design and the relatively small cohort size, which limit generalizability and the control of potential confounding that may exist between the two groups including injury severity score, non-random device allocation, and coil heterogeneity may therefore be clinically consequential. The study is also limited by heterogeneity in indications for splenic artery embolization and a lack of predefined criteria for splenectomy, which may introduce selection bias. Due to the small sample size, stratified analyses by indication were not performed, which may limit assessment of indication-specific outcome differences if present. Moreover, the cohort predominantly comprised patients undergoing SAE for traumatic splenic injury; therefore, the generalizability of these findings for non-traumatic SAE indications may be limited. Although the procedures were performed by experienced interventional radiologists, operator preference, and technique variability could have contributed to the increased fluoroscopy times observed in the coil group. Furthermore, while splenic infarction was observed less frequently in the LOBO group, this finding should be interpreted cautiously, given the limited follow-up imaging and the possibility that infarction may also occur as a direct consequence of the underlying traumatic injury itself, independent of embolization technique. Finally, real-world factors such availability, operator learning curve, as well as device cost, which were not assessed in this study, should be considered when selecting an embolic platform for distal splenic occlusion. Procedural costs, in particular, are challenging to compare reliably across patients because they are influenced by payer-specific factors such as insurance coverage, reimbursement structures, and negotiated payment rates [25].