Transplantation of a Horseshoe Kidney

Abstract

Because of the continuing organ shortage, kidneys with atypical anatomy are frequently considered for transplantation. The most common anatomic variation of the kidney is the horseshoe kidney, with an incidence of 1 in 800. These kidneys are frequently accompanied by vascular and urinary tract abnormalities and there has always been a concern for primary nonfunction based on technical failure (1, 2). Discard of potentially usable horseshoe kidneys can occur because of vascular anatomic limitations or injuries. According to a recent report of horseshoe kidneys that were donated within the Eurotransplant region, 27% were discarded immediately and 9.6% were discarded after division. The reason was the complex vascular anatomy in at least 53.8% and 60%, respectively (3). We present a case of whole horseshoe kidney transplantation after extensive vascular reconstruction. A horseshoe kidney from a 52-year-old male deceased donor was accepted at the University of Pittsburgh Medical Center. The cause of death was a cerebrovascular accident. The backtable wedge kidney biopsy showed 10% glomerulosclerosis and mild interstitial fibrosis, arteriosclerosis, and arteriolosclerosis. The horseshoe kidney had been recovered en bloc with the accompanying aorta and inferior vena cava (IVC). The arterial supply to the horseshoe kidney consisted of two right hilar renal arteries connected to the aorta, two left hilar renal arteries that were transected at their common orifice at the aorta, an isthmic artery (previously a branch of the right external iliac artery), and a left superior pole artery transected midway from its aortic origin. Venous drainage consisted of bilateral double renal veins to the IVC. Reconstruction was performed by anastomosis of the hilar arteries to the single orifice at the original site on the aorta, the left superior pole artery to its transected branch, and the isthmus artery to a newly created orifice at the inferior aorta. The superior poles of the aorta and IVC were oversewn (Fig. 1).FIGURE 1.: Arterial vascular reconstruction of horseshore kidney.The recipient was a 63-year-old female with end-stage renal disease secondary to tacrolimus toxicity after lung transplantation. The recipient operation was performed through a standard extraperitoneal approach in the right iliac fossa. Revascularization was accomplished by anastomosis of the inferior IVC and aorta to the external iliac artery and vein, respectively. The ureters were anastomosed to the bladder using separate extravesical ureteroneocystostomies. The cold ischemia and anastomosis times were 34 hr and 35 min, respectively. Both kidneys reperfused entirely. Immunosuppression consisted of induction with daclizumab and maintenance immunosuppression with tacrolimus, mycophenolate mofetil, and prednisone. There were no vascular or ureteral complications. The serum creatinine was 1.6 mg/dL two weeks posttransplantation. Our decision to transplant the whole horseshoe kidney as a single kidney rather than divided into two kidneys was due to the presence of an isthmic artery. Horseshoe kidneys have previously been transplanted successfully with reasonable results. Due to the organ shortage, efforts to overcome the anatomic challenges of horseshoe kidneys are worthwhile. Anthony T. Corcoran Ron Shapiro Liise K. Kayler Department of Surgery University of Pittsburgh Medical Center Pittsburgh, PA