During evaluation for the repair of an expanding abdominal aortic aneurysm, a patient is discovered to have a horseshoe kidney. The optimum surgical approach is:
|A||Midline abdominal incision, preservation of the renal isthmus|
|B||Midline abdominal incision, division of the renal isthmus|
|C||Retroperitoneal approach, implantation of anomalous renal arteries|
|D||Nephrectomy, repair of aneurysm, chronic dialysis|
a. Horseshoe kidney is the most common urologic anomaly, occurring in approximately 0.25% of the population.
b. Despite this relatively high incidence, AAA associated with horseshoe kidney is rare.
c. Symptoms of horseshoe kidney are periumbilical abdominal pain or colic due to pyelocaliceal lithiasis.
d. Surgical treatment of AAA associated with horseshoe kidney requires special consideration because of abnormal anatomy.
e. The isthmus of the horseshoe kidney almost always lies over the aneurysm, which makes exposure more difficult.
f. Accessory renal arteries are present in 80% of cases.
g. The ureters of horseshoe kidneys are located more medial than normal, and anterior to the renal isthmus.
h. Accurate preoperative diagnosis and well-designed surgical strategies are required.
i. Sixteen-channel multidetector CT is very useful for detecting accessory arteries..
j. An intravenous pyelogram is helpful for delineating the location of the ureters to prevent ureteral injury.
k. The optimal approach to the abdominal aorta in patients with horseshoe kidney remains controversial.
l. The isthmus can be separated safely if it is thin and contains little parenchyma; otherwise, division should be avoided because of retroperitoneal urinary leak, infection, bleeding or renal ischemia.
m. Retroperitoneal exposure is recommended because of improved vision, reduced risk of ureteral injury and enhanced ability to reimplant anomalous renal arteries.
n. Endovascular aneurysm repair is a good option for AAA in the presence of a horseshoe kidney, although possible complications, such as occlusion of accessory renal arteries and the developmentof type 2 endoleaks, are concerns.