Prospective radionuclide renal function evaluation and its correlation with radiological findings in patients with Kock pouch urinary diversion.

In an attempt to understand better the status of renal function after Kock pouch urinary diversion we conducted a prospective evaluation of renal function in 25 patients using the radionuclide 131iodine-hippurate. Studies were done before, and at 1 month and every 6 months for 30 months postoperatively. The radionuclide results were then compared to excretory urography and contrast study of the reservoir. Our renal function study included the determination of individual and total effective renal plasma flow (ml. per minute), the time to maximal radioactivity over the kidney (peak time in minutes) and a renogram. The mean total (both kidneys) effective renal plasma flow rates before (25 patients) and at month 1 (19), month 6 (14), month 12 (12), month 18 (6), month 24 (6) and month 30 (7) after operation were 385.5 +/- 112.2, 310.5 +/- 109.9, 362.7 +/- 69.2, 442.0 +/- 97.5, 468.2 +/- 82.5, 405.7 +/- 70.6 and 414.0 +/- 65.1, respectively. A comparison of individual and total effective renal plasma flow before and after operation revealed that only the change of the flow at each or both sides of the kidney before and at 1 month after the operation reached statistically significant differences, respectively (p less than 0.05, paired t test). Postoperatively 5 of 6 patients with hydronephrosis had abnormal peak time and a third segment on the renogram was performed on the corresponding side of the kidney. No reflux was noted on contrast study of the reservoir of any patient followed for up to 30 months. In conclusion, the radionuclide renal function evaluation showed a significant decrease of renal function 1 month after Kock pouch diversion, then it resumed and remained stable (neither improved nor deteriorated) for 30 months. Also the abnormal peak time and third segment on the renogram usually implicated a dilated upper urinary tract.