Corona mortis in the setting of pelvic trauma: Case series and review of the literature

INTRODUCTION

Corona mortis, or “crown of death,” has been defined as a variant vessel that originates from the external iliac artery system and dives deep into the pelvis, crossing the superior pubic ramus, potentially creating an arterial or venous anastomosis with branches of the internal and external ipsilateral iliac vessels.^[1] The connections between the obturator artery, typically an internal iliac artery branch, and an external iliac artery branch or the external iliac artery have prompted a more comprehensive definition of corona mortis that reflects the potential problem for surgeons in the retropubic region, and not simply describing the anatomy.^[2] Thus, corona mortis can be defined as any vessel crossing the superior pubic ramus.^[3]

Corona mortis is not typically taught during medical training, with most anatomy textbooks labeling corona mortis as “anomalous,” “aberrant,” or “accessory” despite published reports noting an arterial prevalence of 17–25% and a venous prevalence of 41.7–42%.^[4,5] In addition, training often fails to emphasize the importance of identifying corona mortis, particularly given the location behind the pubic ramus that predisposes the vessel to injury in pelvic surgeries and trauma, a bleeding control challenge intraoperatively when a lacerated vessel spasms.^[4] Injury to the arterial corona mortis is associated with severe adverse outcomes, resulting in rapid hemodynamic instability and death if left unrecognized.^[6]

Catheter-guided embolization provides a minimally invasive alternative to rapidly achieve prompt hemostasis in cases of pelvic trauma, as it can selectively embolize a particular vessel without exposing the patient to surgical risk.^[7] Following Institutional Review Board approval utilizing universal consent, we outline four reports of pelvic trauma resulting in hemorrhage due to the presence of arterial corona mortis and successful catheter-guided embolization.

CASE REPORTS

Case 1

Following a motor vehicle collision, an 81-year-old male presented to the emergency department (ED). Contrast-enhanced computed tomography (CT) of the abdomen and pelvis revealed bilateral fractures of the pubic rami (superior and inferior); active contrast extravasation was present within the left gluteal musculature. A small abnormal branch of the left external iliac artery was noted [Figure 1a]. Emergent angiography was performed due to hypotension. The obturator artery was noted by angiogram to arise directly from the external iliac artery, extending into the deep pelvis, and creating corona mortis [Figure 1b]. Selective angiography of the obturator muscle bed further demonstrated active bleeding [Figure 1c]. Gelfoam (Pfizer, New York, NY) embolization was performed, followed by coil embolization (Concerto coils, Medtronic, Minneapolis, MN). Post-embolization angiogram confirmed hemostasis [Figure 1d]. Following fracture stabilization, the patient was discharged on hospital day 10.

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Figure 1:

An 81-year-old male with bilateral fractures of the pubic rami (superior and inferior) and active contrast extravasation within the left gluteal musculature following a motor vehicle accident. (a) Contrast-enhanced coronal CT image of the pelvis demonstrating a small vessel arising from the left external iliac artery (white arrow). (b) Left external iliac angiogram confirming a corona mortis (white arrow) arising directly from the left external iliac artery separate from the inferior epigastric artery (black arrow). (c) Selective angiogram of corona mortis with a microcatheter showing multiple small foci of arterial contrast extravasation (white arrows). (d) Angiogram status post coil embolization (white arrow) of corona mortis with resultant hemostasis.

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Case 2

A 47-year-old male was admitted to the ED with injuries sustained in a motorcycle accident. Intravenous contrast-enhanced CT demonstrated an anterior-posterior compression III pelvic injury demonstrating sacroiliac joint widening; the left pelvis demonstrated contrast extravasation [Figure 2a]. Active arterial contrast extravasation was also noted by angiography from the left internal iliac artery near the left pubic symphysis [Figure 2b]. Embolization of the left internal iliac artery anterior division utilizing Gelfoam slurry was performed. Follow-up angiogram demonstrated active arterial extravasation from a corona mortis [Figure 2c], a branch of the left inferior epigastric artery originating from the left inferior epigastric artery in communication with the left internal iliac artery anterior division. Coil embolization (Concerto coils, Medtronic, Minneapolis MN) of the corona mortis was performed; a follow-up angiogram demonstrated no further hemorrhage [Figures 2d-f]. His pelvic fractures were internally fixated and he was discharged 15 days post-embolization.

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Figure 2:

A 47-year-old male with an anterior-posterior compression III pelvic injury, sacroiliac joint widening, and active arterial contrast extravasation within the deep pelvis near the left pubic symphysis following a motorcycle accident. (a) Axial contrast-enhanced CT of the pelvis demonstrates active arterial extravasation of contrast (white arrow) anterior to a widened pubic symphysis. (b) Selective angiogram of the left internal iliac artery shows an active arterial bleed (white arrow) within the left deep pelvis due to reflux through the left external iliac artery. (c) Repeat right internal iliac artery angiogram after gelfoam embolization demonstrates bleeding (white arrow) arising from corona mortis arising from the right inferior epigastric artery (black arrow). (d) A 47-year-old male with an anterior-posterior compression III (APC) pelvic injury, sacroiliac joint widening, and active arterial contrast extravasation from the left internal iliac artery near the left pubic symphysis following a motorcycle accident. An angiogram of the left external iliac artery better demonstrates the bleed (white arrow) arising from corona mortis. (e) Post coil (white arrows) embolization of corona mortis showing no further hemorrhage. (f) Final angiogram of the right internal iliac artery demonstrating no further extravasation of contrast. Embolization coils are labeled with white arrows.

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Case 3

A 61-year-old male presented to the ED with multiple pelvic fractures following a car accident. The patient presented as hemodynamically stable. Contrast-enhanced CT of the pelvis showed multiple displaced pelvic fractures, bilateral pelvic hematomas, and a right-sided corona mortis vessel [Figures 3a-c]. Angiography demonstrated multifocal blush on the right hemipelvis [Figure 3d]. The right corona mortis arising from the external iliac artery was readily identified, demonstrating active contrast extravasation on selective angiogram [Figure 3e]. The variant artery was successfully embolized with Gelfoam [Figure 3f]. The patient was discharged post-procedure on day 5.

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Figure 3:

A 61-year-old male with multiple displaced pelvic fractures, bilateral pelvic hematomas, and multifocal blush on the right hemipelvis following a motor vehicle accident. (a) Right-sided corona mortis (arrowhead), the pubic branch of the inferior epigastric artery (blue arrow), obturator artery arising from the anterior division of the internal iliac artery (curved arrow), and lateral pelvic hematoma (star). (b) Oblique coronal and (c) oblique sagittal multiplanar reconstruction of the CTA images demonstrating the course of the right corona mortis (CM and arrow) originating from the external iliac artery (EIA and arrow), coursing behind the superior pubic ramus (SPR) and towards the obturator foramen (OF). (d) A volume-rendered CT pelvic angiogram shows the right obturator artery (arrow), that is, corona mortis arising from the right external iliac artery (arrowhead). (e) Selective angiogram through the right corona mortis (arrow) shows multiple areas of contrast extravasation in the region of the right obturator foramen (arrowheads). (f) Post-embolization images of the right corona mortis artery using gelfoam shows complete cessation of areas of extravasation (arrows).

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Case 4

A 64-year-old female presented to the ED after falling at home. She was initially hemodynamically stable. Contrast-enhanced pelvic CT showed a right acetabular fracture with active extravasation and a pseudoaneurysm lateral to an aberrant right obturator artery [Figures 4a and 4b]; angiography was performed in the interventional radiology (IR) suite. Investigation of the right internal iliac artery demonstrated patency of the right internal iliac artery and branching vessels without evidence of active extravasation. An arteriogram of the right external iliac artery was performed, revealing a slight blush of contrast from an aberrant right obturator artery. This artery originated from the mid-right external iliac artery and shared a common trunk with the inferior epigastric artery [Figure 4c]. It then traveled over the superior pubic ramus before entering the obturator foramen, forming a corona mortis [Figure 4d]. Embolization of the corona mortis was then performed using Concerto detachable coils (Medtronic, Minneapolis, MN) with no further evidence of active bleeding or pseudoaneurysm [Figure 4e]. The patient was discharged on post-procedure day 7.

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Figure 4:

A 64-year-old female with a right acetabular fracture with the right pelvic sidewall hematoma and a pseudoaneurysm lateral to an aberrant right obturator artery after falling at home. (a) Contrast-enhanced axial CT image shows a 6mm pseudoaneurysm (arrow) within the right lateral pelvic sidewall, pelvic hematoma (star), and right acetabular fracture (arrowhead). (b) Curved coronal reconstruction contrast-enhanced CT image demonstrating the aberrant right obturator artery arising from the external iliac artery representing the corona mortis (arrowhead). (c) The aberrant right obturator artery arising from the external iliac artery (EIA), represents the corona mortis (arrowhead). Note the common origin of the corona mortis and inferior epigastric artery (IEA). (d) Super-selective catheterization of the corona mortis showing the distribution of vasculature around the obturator foramen and the pelvic pseudoaneurysm (arrow). (e) DSA images post-coil embolization of the corona mortis (arrow). Concerto coils can be seen.

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DISCUSSION

Management of pelvic trauma typically includes placement of a pelvic binder, with CT on the vast majority of patients and FAST for unstable patients. Patients positive for FAST are treated surgically with pre-peritoneal packing; if FAST is negative, IR is typically consulted for angioembolization. Corona mortis is defined as an “anastomosis between the obturator and the external iliac or inferior epigastric artery or vein” and any other vessels, posing a risk of hemorrhage to surgeons operating in the space posterior to the superior pubic ramus.^[2,3,8] Corona mortis is classified by the Rusu et al. system into three main categories (I. Arterial, II. Venous, III. combined), with further classification into subcategories based on morphological patterns.^[3] In our series, Cases 1 and 4 could be classified as the most common form, Rusu et al. type I.1 variant, while Cases 2 and 4 could be classified as Rusu et al. type I.2.

Various definitions have resulted in discrepancies in the documented prevalence of corona mortis. A comprehensive literature search identified corona mortis cases from cadaveric, intraoperative, radiologic, and individual case studies [Table 1^[1-3,8-52] and 2^[6,53-75] Figure 5]. Arterial corona mortis in cadaveric and intraoperative studies reported the widest range, with averages of 30.13% and 35.14%, respectively, possibly related to intraoperative spasm of a lacerated corona mortis, making definitive identification of corona mortis challenging.^[8] Radiologic studies reported a lower prevalence, with a mean of 26.2%. Interestingly, two separate meta-analyses reported arterial corona mortis prevalence as 17% and 25%, respectively, which is much lower than our evaluation of the literature (8.3– 86%; [Tables 1 and 2]) Venous corona mortis prevalence was reported to be higher than arterial corona mortis, at approximately 50% overall.^[4,5] Arterial corona mortis poses the greatest risk for surgeons and interventionalists in the setting of pelvic trauma, suggesting that corona mortis is not uncommon, and thorough mapping of the vasculature is essential.

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Figure 5:

Illustration. An illustration representing the two variants of corona mortis noted in our case series. In two of the four cases, the corona mortis was found as a branch off of the external iliac artery (Rusu type I.1). In two cases the corona mortis was identified as a branch of the inferior epigastric artery, which communicated with the anterior division of the internal iliac artery (similar to Rusu type I.2).

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An isolated pubic ramus fracture can often be treated with conservative management; however, in cases involving a corona mortis, patients are at risk of delayed hemorrhage.^[63] These vessels are deep within the pelvis and are often challenging to identify during surgery due to spasm.^[8] It is not surprising that, of the traumas that documented fracture of the pubic rami (n = 13) and of 12 traumas that mentioned hemodynamic status, all of the patients exhibited delayed hemorrhage [Table 2]. Interestingly, of the four patients in which corona mortis was identified intraoperatively, 50% were hemodynamically stable, and 50% had delayed hemorrhage. The three corona mortis identified post-operatively (n = 3) had only one (33%) with delayed hemorrhage, suggesting more success in corona management during non-trauma operative procedures. Awareness and early recognition of the corona mortis variant by radiologists in cases of trauma are vital.

The sensitivity and specificity of CT angiography (CTA) in identifying corona mortis in non-pelvic fracture patients are 90% and 100%, respectively. This vessel could be missed on initial CT without angiography as the sensitivity and specificity decrease to 63.6% and 92.3% in the setting of pelvic fracture.^[38] However, an evaluation of the case reports [Table 2] indicated that all trauma cases utilized CTA successfully to identify corona mortis. More importantly, all of the cases were successfully managed using embolization.

CONCLUSION

In the setting of pelvic fracture, it is essential to identify corona mortis as an injury may result in a life-threatening hemorrhage due to its position over the superior pubic ramus. Thus, careful radiological evaluation of corona mortis is key to preventing delayed life-threatening hemorrhage, as this entity is more common than previously thought. The interventionist needs to focus on the external iliac artery during catheter angiography in all cases of pelvic trauma, as the data suggest that the obturator artery may arise from that location in greater than 25% of cases.

In the setting of pelvic injury or pelvic surgery, catheter-guided embolization provides quick and successful management of hemorrhage.^[7]