Prediction of partial nephrectomy outcomes by using the diameter-axis-polar nephrometry score

To evaluate the utility of diameter-axis-polar nephrometry score to evaluate partial nephrectomy outcomes.

Renal tumors of 127 patients with a functional contralateral kidney who underwent partial nephrectomy were scored using the diameter-axis-polar and R.E.N.A.L nephrometry scores. The mean tumor diameter was 2.9 cm (range 1.0-8.0 cm) and warm ischemic time was 27.3 min (range 12-46 min). All patients underwent (99m)Tc- mercaptoacetyltriglycine renal scintigraphy preoperatively and 6 months postoperatively to assess effective renal plasma flow. We compared nephrometry scores with estimated glomerular filtration rate, effective renal plasma flow and ischemic time.

The mean serum creatinine level was 0.84 mg/dL preoperatively and 0.93 mg/dL at 6 months postoperatively. The mean estimated glomerular filtration rate decreased from 74.2 to 66.9 mL/min/1.73 m(2) . Effective renal plasma flow of the operated kidney decreased to 73.5% from baseline (from 157.0 to 114.3 mL/min/1.73 m(2)). Univariate and multivariate analyses showed that diameter-axis-polar score had a stronger association with the percent change in estimated glomerular filtration rate, effective renal plasma flow in the treated kidney and ischemia time compared with the R.E.N.A.L score.

Diameter-axis-polar nephrometry score is a useful tool for the assessment of small renal tumors amenable to partial nephrectomy, and it better predicts postoperative functional changes and ischemic time compared with the R.E.N.A.L nephrometry score.