Residual kidney function after unilateral nephrectomy. Pre- and postoperative estimation by renography and clearance measurements.

The residual kidney function was predicted from preoperative renography and determination of the glomerular filtration rate (GFR) in 57 patients undergoing unilateral nephrectomy for cancer, postrenal obstruction or renovascular hypertension. Postoperative GFR measurements were carried out 6-36 months after the operation. In eleven patients where the kidney removed had no function, no significant difference was found between pre- and postoperative GFR values. In 46 patients where the kidney removed had some function, the preoperative estimate was a little too high in only two patients. In this group, the postoperative GFR on an average amounted to 42% above the preoperatively predicted value. We conclude that the combination of 51Cr-EDTA clearance and renography is a reliable, non-invasive method for determination of the minimum residual kidney function before unilateral nephrectomy is carried out.