Evaluation of cases where the right kidney is higher than the left kidney.

摘要

BACKGROUND: Finding the right kidney higher than the left kidney on excretory urography (EXU) is unusual. In the present study, the position of the kidneys was evaluated in patients, and the frequency, causes or attribution were investigated. METHODS: Kidney positions were evaluated in 1625 patients. Subsequent evaluations by computed tomography scan were performed for each case where the right kidney was higher than the left. If a patient had right hydronephrosis, bladder evaluations such as ultrasonography and/or cystoscopy were also conducted. Patients with a left contracted kidney were excluded. RESULTS: The right kidney was higher than the left in 81 (5%) of 1625 cases. In 30 cases (37%), the cause or attribution existed in the right urinary tract. Eleven of these cases were due to tumors or cysts in the right kidney, four were due to congenital anomalies, and 15 were due to hydronephrosis. In 10 (12.3%) of the cases, the cause or attribution existed in the left urinary tract. All of them were cysts or tumors of the left kidney. Of the other 13 (16.0%) cases, eight were caused by hepatatrophy and splenomegaly as a result of liver cirrhosis, two were caused by aortic aneurysm, one was caused by visceral inversion, one was caused by a right ovarian tumor, and one was caused by pneumonectomy. Malignancies, including two renal cell carcinomas and three bladder cancers at the right ureteral orifice, were found in five cases (6%). CONCLUSION: The above results suggest that the right kidney is higher than the left in five percent of all cases undergoing EXU. In cases where the right kidney is higher than the left, and a left contracted kidney cannot be found, further evaluation is recommend.