[Surgery of abdominal aorta with horseshoe kidney]

Seventy one surgical procedures on abdominal aorta in patients with horseshoe kidney have been reported in literature until 1980. Bergan reviewed 30 operations of abdominal aortic aneurysms (AAA) in these patients until 1974. Of them 3 AAA were ruptured. Gutowitz noticed 57 surgically treated AAA in patients with horseshoe kidney until 1984. Over the period from 1991 to 1996 thirty nine new cases were reported , including 2 ruptured AAA. The surgery of the abdominal aorta in patients with horseshoe kidney is associated with the following major problems: -reservation of anomalous (aberrant) renal arteries; reservation of the kidney excretory system; approach to the abdominal aorta (especially in patients with AAA) and graft placement The aim of the paper is the presentation of 5 new patients operated for abdominal aorta with horseshoe kidney. Over the last 12 years (January 1, 1984 to December 31, 1996) at the Centre of Vascular Surgery of the Institute of Cardiovascular Diseases of the Clinical Centre of Serbia, 5 patients with horseshoe kidney underwent surgery of the abdominal aorta. There were 4 male and one female patients whose average age was 57.8 years (50-70). Patient 1. A 50-year-old male patient was admitted to the hospital for disabling claudication discomforts (Fontan stadium IlI) and with significantly decreased Ankle-Brachial indexes (ABI). The translumbal aortography showed aorto-iliac occlusive disease and horseshoe kidney with two normal and one anomalous renal artery originating from infrarenal aorta (Crawford type II). Intravenous pyelography and retrograde urography showed two separated ureters. The aorto-bifemoral (AFF) bypass with Dacron graft was done with end-to-end (TT) proximal anastomosis just under the anomalous renal artery. The graft was placed behind the isthmus. During a 12-year follow-up renal failure, renovascular hypertension and graft occlusion were not observed. Patient 2. A 53-year-old male patient was admitted to the hospital for symptomatic AAA. Two years before admission the patient underwent coronary artery bypass grafting. The Duplex scan ultrasonography and translumbal aortography showed an infrarenal AAA, aneurysm of the right iliac artery and horseshoe kidney with two normal and one anomalous renal artery originating from the left iliac artery (Crawford type III). Intravenous pyelography and retrograde urography showed two separated ureters. After partial aneurysmectomy, the flow was restaured using bifurcated Dacron graft placed behind the isthmus. The right limb of the bifurcated graft was anastomosed with the common femoral artery and the left limb with left iliac artery just above the origin of the anomalous renal artery. The first day after operation thrombosis of the left common femoral artery with leg ischaemia was observed. (That artery was cannulated for ECC during coronary artery bypass grafting 2 years ago). The revascularisation of the left leg was done with femoro-femoral cross over bypass. During a 11-year follow-up period, the graft was patent and renal failure or revascular hypertension were not observed. Patient 3. A 66-year-old male patient was admitted to the hospital for rest pain (Fontan stadium III) and significantly decreased ABI. The patient had diabetes mellitus and myocardial infarction two months before admission. Translumbar aortography showed an aorto-iliac occlusive disease associated with horseshoe kidney with 5 anomalous renal arteries. (Crawford type III). Due to high risk, the axillo-bifemoral (AxFF) extra-anatomic bypass graft was performed. Five years after the operation the patient died due to new myocardial infarction. During the follow-up period the graft was patent and there were no signs of renal failure and renovascular hypertension. Patient 4. A 50-year old male patient was admitted to the hospital for high asymptomatic AAA. The diagnosis was established by Duplex scan and translumbal aortography. The large infrarenal AAA (transverse diameter 7 cm) associated with horseshoe kidney with two normal renal arteries (Crawford type I) were found. Intravenous pyelography and retrograde urogrpahy showed two separated ureters. After partial aneurysmectomy the tubular Dacron graft was placed behind the isthmus. During a 15-month follow-up the graft was patent and there were no signs of renal failure and renovascular hypertension. Patient 5. A 70-year-old female patient was admitted to the hospital for large asymptomatic AAA. The Duplex ultrasonography, CT scan, NMR and translumbal aortography showed an infrarenal AAA, aneurysms of the both common iliac arteries, aneurysm of the left hypergastric artery and horseshoe kidney with two normal and two anomalous renal arteries. One of the anomalous renal arteries originated from AAA, and the other from the left common iliac artery (Crawford type II). Intravenous pyelography and retrograde urography showed two separated ureters. After partial aneurysmectomy the flow was restaured using bifurcated Dacron graft placed behind the isthmus. The right limb of the graft was anastomosed (TT) with bifurcation of the common iliac artery and the left limb with the distal part of the common iliac artery (end-to-side) just above the origin of the second anomalous renal artery. The first anomalous renal artery that originated from AAA was removed from the aneurysm wall and anastomosed with graft using Carrel patch technique. During a 9-month follow-up the graft was patent and there were no signs of renovascular hypertension and renal failure. The horseshoe kidney is a rare anomaly of the urinary system. The incidence of this anomaly is from 1:1600 to 1:400 In 95% of cases the kidneys are connected with the lower poles, while in 5% with the upper poles In most cases, the isthmus structure is parenchimatous structure, and rarely it consists of the connective tissue. Usually the isthmus is located in front of the abdominal aorta and inferior vena cava, and very rarely behind them In two thirds of patients anomalous vascularization is present There are two classifications of anomalous vascularization: Papin's and Crawford's. According to Papin's classification, based on the number of renal arteries, there are three types of horseshoe kidney vascularization: Papin I (20%): There are two normal renal arteries only. (One of our 5 patients); Papin II (66%): There are 3-5 renal arteries. (Four of our 5 patients); Papin III (14%): There are more than 5 renal arteries. The Crawford's classification based on the origin of renal arteries, is of greater surgical importance than Papin's. According to it there are also three types of vascularization: Crawford I: There are two renal arteries with normal origin. (One of our 5 patients); Crawford II: Besides two normal, there are 1-3 anomalous renal arteries originating from the infrarenal aorta or iliac arteries (Three of our 5 patients); Crawford III: All renal arteries have an anomalous origin. (One of our 5 patients). The patients with horseshoe kidney can also have two separated, or one connected excretory urinary systems. All our 5 patients had two separated ureters. There is no specific clinical manifestation of the horseshoe kidney. Urinary infection or calculosis are very frequent as are in other urinary anomalies. The diagnosis of horseshoe kidney is established by Dupplex ultrasonography, CT scan, NMR, radionuclide scintigraphy and angiography. Very often the diagnosis is established occasionally during the examination of aneurysmal and occlusive diseases of the abdominal aorta. In cases of AAA or AIO associated with horseshoe kidney preoperative vascularization and condition of the excretory system should be established. Besides standard translumbar aortography selective renovasography is often neccessary. In some cases the intraoperative angiography or arterial identification, with metallic probe must be done. All renal arteries are "terminal" without significant anastomosis on the side of the kidney. Therefor its preservation is neccessary. There are three ways. The first is the location of anastomosis (3 of our patients). The second is an AxFF bypass, but only in patients with AIO (One of our patients and in the third reimplantation of the renal artery using Carrel patch technique was performed (One of our patients). The Isthmus of the kidney aggravates aortic preparation especially in patients with AAA. Sometimes isthmectomy is neccessary. In such cases there is danger of urinary fistula. Therefor many authors suggest the left extraperitoneal approach to abdominal aorta. In our patients, the transperitoneal approach was used, isthmectomy was not neccessary and graft was placed behind the isthmus. The operation of the abdominal aorta in patients with horseshoe kidney can be difficult due to anomalous renal arteries, anomalous excretory urinary system and is Ehmus. In these patients a more precise preoperative diagnosis is neccessary.