[Results of operative therapy of double kidney]

107 patients were submitted to operative treatment of a duplex kidney from 1968 to 1980. In 62 kidneys of children heminephrectomy was performed and in 26 parenchymapreserving operations like ureterocystoneostomies (n = 17) and pyelopyelostomies (n = 9) were done. Fever and urinary tract infection was seen more often in patients submitted to partial ureterectomy than after total ureterectomy. Long time follow-up (medium 8.8 years) was available in 33% of the children. Two non-functioning renal units after heminephrectomy and one recurrent vesicoureteral reflux were documented. Renal length was determined by planimetry. While values within the +/- 2SD range were seen after antireflux surgery and after pyelopyelostomies growth of the kidneys after heminephrectomy seemed to be hampered. Although renal hypoplasia and dysplasia is seen in a lot of duplex kidneys, heminephrectomy should not be done routinely. Preoperative planimetry of the kidney gives information about the amount of parenchyma most probably lost by heminephrectomy. In addition malfunction of the contralateral "good" kidney should be suspected, if compensatory hypertrophy of this kidney does not develop in spite of a grossly scarred contralateral kidney.