Isolated iliac aneurysms are uncommon, and their management becomes more complex when they coexist with ectopic pelvic kidneys [1,2]. This congenital anomaly alters vascular anatomy, posing significant diagnostic and therapeutic challenges. The blood supply to the pelvic kidney may originate from the common iliac artery (CIA), external iliac artery (EIA), internal iliac artery (IIA), aortic bifurcation, or inferior mesenteric artery (IMA), requiring careful preoperative planning to ensure aneurysm exclusion and preservation of the renal blood supply [3-5].

According to the European Society of Vascular Surgery guidelines for iliac aneurysms, the selection of an appropriate surgical technique should be based on both patient and lesion characteristics (Class IIa, level B) [6]. Over recent decades, endovascular approaches have gained increasing popularity due to their lower morbidity and shorter hospital stays [6]. Initial techniques involved embolization of the IIA with stent graft coverage of the CIA and EIA. Recently, iliac branch devices (IBDs) have shown promising results and provide a more refined and minimally invasive alternative compared to open surgery, while preserving the IIA [5,6].

The management of iliac aneurysms in patients with concomitant ectopic pelvic kidneys follows a similar approach, incorporating endovascular, open, and hybrid procedures tailored to the patient’s specific anatomical considerations [3-5,7]. Here, we present the case of an isolated CIA aneurysm in a patient with an ectopic pelvic kidney that was managed endovascularly using tubular stent grafts and IIA embolization. This study was approved by the Institutional Review Board of AHEPA University Hospital (IRB No. 37985).

A 58-year-old male was admitted to the vascular surgery department for the management of a large asymptomatic left CIA aneurysm. The aneurysm was incidentally diagnosed during routine imaging for back pain. His medical history included hypertension, dyslipidemia, and a body mass index (BMI) >30 kg/m². Computed tomography angiography (CTA) revealed a 53.5 mm left CIA aneurysm and an ectopic left kidney in the pelvis (Fig. 1). The patient was unaware of these anatomical variations. The main renal artery supplying the ectopic kidney originated from the left proximal CIA near the aortic bifurcation and the kidney was also supplied by two smaller polar arteries originating from the left IIA (Fig. 1).

Figure 1. Preoperative computed tomography angiography image of the iliac aneurysm and ectopic pelvic kidney with the feeding arteries.

The length of proximal sealing zone for the endograft placement was 20 mm from the ectopic renal artery. However, there was no distal sealing zone in the CIA because it was dilated up to the orifice of the IIA (Fig. 2). We decided to perform endovascular repair based on several factors, including the technical challenges posed by the position of the ectopic kidney within the small pelvis and the presence of several comorbidities despite the patient’s relatively young age. Specifically, the patient had a BMI >30 kg/m², hypertension, and chronic obstructive pulmonary disease, which were considered when determining the appropriate approach.

Figure 2. Preoperative measurements of the aneurysm.

Our objective was to exclude the aneurysmal sac while preserving circulation to the ectopic kidney. This was achieved by deploying two Gore Excluder (W. L. Gore & Associates) iliac limbs (16 mm×20 mm×11.5 cm [contralateral access] and 16 mm×12 mm×12 cm [ipsilateral access]) with a 2 cm overlap between them and performing coil embolization (Interlock pushable coil; 15 mm×20 cm, Boston Scientific) of the proximal left IIA to prevent a type II endoleak. In the present case, the proximal neck diameter measured approximately 17 mm, while the diameter of the distal sealing zone in the left EIA was approximately 10 mm. Although an iliac branch endoprosthesis (IBE) could have preserved the direct blood flow to the polar arteries, it was not selected because the left CIA was approximately 110 mm long, which would have required more than two stents for the proximal extension.

Both common femoral arteries were exposed. Using a crossover technique from the right side, the left IIA was catheterized with a 0.035-inch wire and Cobra catheter. A large coil (15 mm×20 cm, Boston Scientific) was then placed to embolize the proximal left IIA, preserving more distal hypogastric branches and reducing the risk of postoperative renal infarction. A 12Fr Dry Seal Flex Introducer Sheath (W. L. Gore & Associates) was used to introduce the first limb from the right side, advancing it over an extra-stiff wire to the left CIA. The first endograft (16 mm×20 mm×11.5 cm) was placed immediately distal to the main renal artery, and the second endograft (16 mm×12 mm×12 cm) was positioned distally with a 2 cm overlap, landing in the left EIA. The second endograft was deployed from the left side using the through-and-through wire technique because of challenges encountered while cannulating the first endograft within the aneurysmal sac from the ipsilateral side. Final angiography confirmed exclusion of the aneurysm and preservation of the main renal artery, without orifice coverage (Fig. 3).

Figure 3. Perioperative images depicting the contralateral catheterization of the internal iliac artery, coil embolization, deployment of the stent grafts, and final angiography.

Preoperative serum creatinine levels were 0.8 mg/dL, with no postoperative changes. The patient was discharged on the third postoperative day without complications and was started on antiplatelet therapy. Follow-up CTA at 1 and 12 months post-intervention showed good patency with no endoleaks, migration, occlusion of the ectopic renal artery, or renal infarction (Fig. 4).

Figure 4. Postoperative computed tomography angiography image at the 1-year follow-up.

Pelvic kidneys are rare congenital abnormalities that occur in approximately 1 in 2,000-3,000 births. There are six types of ectopic kidneys according to their location–pelvic, abdominal, cephalad, crossed, thoracic, and lumbar–with the pelvic type being the least common [3,5,8]. Pelvic kidneys occur when the kidneys fail to ascend during the 4th to 8th week of gestation. Their blood supply usually arises from the CIA or EIA, aortic bifurcation, or IMA [9]. The management of vascular pathology becomes particularly challenging when ectopic kidneys coexist with aneuysms, as preserving renal blood flow while excluding the aneurysm is crucial.

Accessory renal arteries may sometimes exist, and although their coverage is generally well tolerated, they can occasionally result in renal infarction [10]. In this case, two smaller accessory renal arteries originated from the left IIA. After embolization of the proximal IIA, no postoperative renal infarction was observed, demonstrating that covering accessory arteries may be well tolerated in some cases. This outcome suggests that sufficient collateral circulation to the polar arteries from the distal IIA may have played a key role in preventing renal infarction, even after embolization of the proximal IIA.

While iliac aneurysms often involve aneurysmal degeneration of the infrarenal aorta, isolated iliac aneurysms in conjuction with ectopic pelvic kidneys are exceedingly rare [11]. Due to the scarcity of studies on such cases, therapeutic strategies should be individualized to exclude the aneurysm, prevent rupture, and preserve renal function [3,4,8,11]. For decades, open surgery, with or without renal protection techniques, has been the standard treatment option. However, the advent of endovascular techniques has significantly reduced morbidity and mortality, making these approaches preferable when the anatomy is suitable. Specifically, IBDs or IBEs represent a very good option for the endovascular repair of iliac aneurysms while preserving the IIA [12]. According to the manufacturer’s instructions for use, IBDs should be extended into the infrarenal aorta. However, according to Fargion et al. [13], a single IBD placement is also a safe and effective option for patients with isolated CIA aneurysms, offering advantages such as reduced radiation exposure, shorter operative durations, less contrast use, and comparable long-term outcomes compared with more extensive aortoiliac interventions. In our case, the IBE technique was not chosen because the CIA was approximately 110 mm long, which would have required more than two stents for the proximal extension of the IBE, potentially leading to sealing issues and increasing the cost of the intervention.

Tubular stent graft, which were widely used before the advent of IBDs, have been successfully used for the treatment of isolated iliac aneurysms, showing favorable long-term results [14,15]. In this case, we opted for stent grafts covering the CIA to the EIA after embolizing the proximal left IIA, despite the challenge of diameter discrepancies between these two vessels. Improper choice or deployment of the graft can lead to poor sealing, perfusion of the aneurysmal sac, and potential rupture. Another issue was the diameter mismatch, making it difficult to find a stent graft that could accommodate 17 mm proximally and 10 mm distally. Thus, we used two iliac limbs, the first deployed in an upside-down configuration. We chose Excluder tapered aortic stent graft limbs because of their advanced flexibility and conformability, which allowed contralateral access. Few similar cases have reported good long-term outcomes [16-20].

Various stent grafts have been used for this “up-and-over” technique, including the Endurant iliac limb (Medtronic Cardiovascular) [16,17], which features a hydrophilic coating with reduced friction and better trackability; the Zenith iliac limb (Cook Medical) [19,20], offering a wide range of diameter options; and the Excluder contralateral leg [18]. In some cases, the delivery system of the stent graft has been modified extracorporeally to achieve a reverse configuration. However, the extracorporeal deployment and recapture of the stent graft must be carefully considered due to the risk of device damage or failure during final deployment. Additionally, acute aortic bifurcations further complicate the “up-and-over” technique by increasing the likelihood of challenging maneuvers within the vessels, which may lead to device damage, deployment failure, or even intraoperative rupture.

The covered endovascular reconstruction of this iliac bifurcation (CERIB) technique has also been described as a method for managing iliac aneurysms [21-23]. In this approach, balloon-expandable covered stents are deployed in the EIA and IIA using the sandwich technique, followed by ballooning their proximal parts in the distal portion of the iliac limb endoprosthesis [23]. To date, studies have reported good short-term results regarding technical success, patency, and the absence of endoleaks. However, studies with larger patient cohorts and long-term results are required to draw concrete conclusions regarding its use.

This case report highlights the complexities of managing iliac aneurysms in patients with atypical anatomies, such as ectopic pelvic kidneys. Through this report, we aim to contribute to the limited body of literature on this rare condition and offer insights and recommendations for future management of similar cases.

None.

The author has nothing to disclose.

Concept and design: all authors. Analysis and interpretation: all authors. Data collection: all authors. Writing the article: all authors. Critical revision of the article: all authors. Final approval of the article: all authors. Statistical analysis: all authors. Obtained funding: none. Overall responsibility: all authors.