Contrast imaging study of the horseshoe kidney for transplantation.

In the surgical setting, horseshoe kidneys (HKs) may be a cause for confusion because of their complicated morphology, especially in the vicinity of the vascular and urinary collecting systems around the isthmus of the HK. In the patients with HK, analysis of the anatomical structure of the isthmus is both useful and necessary. The aim of this study is to observe the vascular and collecting system of the HK using anatomical and contrast imaging technique, then make use of the knowledge for clinical anatomy. A HK voluntarily donated post-mortem to our department in 2013 by an 80-year-old woman was dissected. The gross anatomy of this HK was reported. In this study, we additionally analyzed this kidney using micro-computed tomography with both colored and colorless contrast media after the kidney was made transparent. Contrast imaging clearly revealed that each of the five renal arteries, including the three surplus renal arteries, entering the HK distributed blood to different regions. Neither side of the urinary collecting system crossed the midline of the isthmus. Two surplus renal veins emerged from the HK and two ureters descended dorsal to the isthmus. These observations show that gross anatomical observation and contrast imaging of the HK can provide very important surgical information. Our results can contribute to both better understanding of fundamental knowledge and progress in the surgery of HKs such as in the setting of biopsy and transplantation.