Follow-up after unilateral nephrectomy in children: is an estimate of glomerular filtration rate necessary?

OBJECTIVE To determine the need for an estimate of glomerular filtration rate (GFR) in the follow-up of children undergoing unilateral nephrectomy for benign renal disease. PATIENTS AND METHODS Forty-four children (21 girls and 23 boys) undergoing unilateral nephrectomy for benign renal disease over a 3-year period were reviewed for the underlying diagnosis and indication for nephrectomy, imaging before and after surgery, postoperative GFR and final outcome. The follow-up included ultrasonography (US) of the contralateral kidney at 3 and 12 months and an estimate of GFR before discharge at ≥ 1 year. All children were aged > 2 years when the GFR was measured. The criteria for discharge were normal imaging of the contralateral kidney before and after surgery and a normal GFR afterward. Spearman's correlation coefficient was used to determine the relationship between age, GFR and contralateral renal length after surgery. RESULTS The median (range) age at surgery was 2.5 (0.67–16) years. The indications for nephrectomy included reflux nephropathy in 18, multicystic dysplastic kidney in 12, a congenital obstructive uropathy in eight, congenital renal dysplasia in four and miscellaneous in two. All patients had a normal contralateral kidney before surgery on US and functional imaging, and normal US at the follow-up, with evidence of compensatory hypertrophy in all. The median (range) corrected GFR for the 44 children was 109 (81–140) mL/min/1.73m2, with no correlation between age and GFR, or between renal length and GFR. CONCLUSION After unilateral nephrectomy for benign renal disease, provided there is a structurally and functionally normal contralateral kidney before surgery, with no abnormality on US, a routine estimate of GFR is unnecessary before discharge from follow-up. There was no correlation between GFR and age or renal length.