Long-term effects of anatrophic nephrolithotomy on selective renal function

To evaluate the long-term changes of selective renal function after anatrophic nephrolithotomy (ANL). A retrospective study was conducted for patients who underwent ANL between January 1995 and December 2016. Inclusion criteria were availability of preoperative and follow-up (1 year or more) radio-isotopic renal scans. Stone-free status was evaluated after 1 month with KUB and ultrasonography or NCCT. Renal isotope scans using 99mTc MAG3 were performed to measure the changes in selective function of the affected kidney (GFR%). Eligible patients were classified into two groups, group 1 patients with stable or improved function and group 2 patients with deteriorated function (> 5% decrease in GFR%). Univariate and multivariate analyses were performed to determine risk factors for deterioration of renal function. The cutoff value for any significant variable was determined using ROC curve. The study included 50 patients with mean age 43.8 + 13.9 years. Complications developed in 26 patients (52%), and stone-free status was documented in 42 patients (84%). After a median follow-up of 2.7 years (range 1–11), mean GFR% of all cases significantly decreased from preoperative value of 52.7% + SD 20 to 45.4% + SD 25% during follow-up (P < 0.001). Deterioration of GFR% was documented in 21 kidneys (42%). Cold ischemia time with a cutoff value 50 min was the independent risk factor (RR 3.986, 95% CI 1.069–14.869, P 0.039). The results of this study support limiting ANL to a selected group of patients and taking all the possible efforts to minimize cold ischemia time below 50 min.