An 81-year-old man was referred from the outpatient clinic to our urology department for symptoms of the lower urinary tract. He had a personal history of arterial hypertension treated with angiotensin converting enzyme inhibitors, surgery for duodenal ulcus in 1961 and cholecystectomy in 2002.
An infrarenal abdominal aortic aneurysm was diagnosed by chance during the abdomino-pelvic ultrasound scan. The CT scan revealed that it did not affect the iliac bifurcation. The examination also showed that the kidneys had a morphology compatible with horseshoe kidneys, with an isthmus located at the level of the infrarenal abdominal aorta. Our case reveals the most favourable situation, in principle, for the surgical approach, since the aneurysm originates distal, 4 cm from the exit of the main renal arteries, which are two, one for each renal half. There is no additional artery at the level of the isthmus.
In successive controls, a progressive increase in the aortic diameter was observed, which, in a control CT scan, had reached a maximum diameter of 8 cm.

In view of these findings, the vascular surgery department decided to consider surgical treatment of the aneurysm.
On physical examination, the patient preserved pulses and an expansive abdominal heartbeat was palpated. The rest of the examination was of no interest.
As part of the preoperative protocol for aneurysms, a baseline echocardiogram and respiratory function tests were performed, all without significant alterations.
A retroperitoneal approach was chosen with resection of the infrarenal aortic aneurysm and aorto-aortic bypass with a 16 mm Hemashield prosthesis, without intraoperative complications. And no lumbar or polar arteries were visualised.
The postoperative course was normal, with no complications arising from the procedure, and the patient maintained adequate renal function. At discharge, all pulses were present.
The patient was asymptomatic in terms of vascular alteration; he maintained all pulses in the lower extremities, with preserved renal function parameters and a control CT angiography 6 months after the operation showed aorto-aortic bypass without leaks or evidence of areas of aneurysmal dilatation.

An intravenous urography was also performed, showing the kidneys with horseshoe morphology, pyeloureteral junction in the anterior plane without significant alterations, as well as in the collecting systems.