Followup of unilateral renal function after laparoscopic partial nephrectomy.

ABSTRACT

PURPOSE: We assessed the change in unilateral renal function after laparoscopic partial nephrectomy to determine factors affecting the course and factors predicting the postoperative glomerular filtration rate decrease. MATERIALS AND METHODS: From prospectively collected data on 116 patients who underwent laparoscopic partial nephrectomy we evaluated the glomerular filtration rate of the operated kidney using diethylenetriaminepentaacetic acid scans done preoperatively, and 3 months, and 1, 2 and 3 years postoperatively. Kidney volume was measured from the arterial phase of dynamic computerized tomography of the kidney done before and 3 months postoperatively to calculate the volume reduction. We analyzed clinicopathological and operative factors with the potential to influence the perioperative glomerular filtration rate decrease. RESULTS: In all patients the glomerular filtration rate was significantly decreased by 3 months postoperatively. It remained significantly lower compared to preoperative function despite the trend toward progressive recovery, which was noted until 3 years postoperatively. Recovery in individuals was significantly influenced by patient age (less than 55 vs 55 years or greater), medical comorbidities, tumor size (less than 2.5 vs 2.5 cm or greater), kidney volume reduction (less than 20% vs 20% or greater) and collecting system repair at surgery. Independent determinants of postoperative renal function were the preoperative glomerular filtration rate (ß = 0.410, 95% CI 0.424-1.084; p <0.001), the percent of renal parenchymal volume reduction (ß = 0.273, 95% CI 0.168-0.766; p = 0.003) and pelvicalyceal system repair (ß = 0.284, 95% CI 2.960-15.788; p = 0.005). CONCLUSIONS: Function of the kidney undergoing laparoscopic partial nephrectomy progressively recovers after a significant decrease immediately after surgery. Although recovery differs according to patient age, comorbidities and tumor size, factors that independently predicted the postoperative glomerular filtration rate decrease were the renal parenchymal volume reduction and pelvicalyceal system repair.