Are Preoperative Parameters of Unilateral Pyelo-ureteric Junction Obstruction in Children Predictive of Postoperative Function Improvement?

Abstract

Surgery on the pyelo-ureteric junction obstruction (PUJO) has long been thought to affect postoperative renal function. However, preoperative assessment of which kidneys will benefit from such surgery remains unreliable. Pre- and postoperative data relating to renal function were obtained by renal scan for 69 patients who were operated upon for PUJO. These patients were divided into two groups: group A (improved differential renal function) and group B (unimproved or decreased differential renal function). The two groups were then compared with regard to age at operation and presence or absence of clinical symptoms. Ultrasound (anteroposterior diameter of the pelvis, parenchymal thickness) and renal scan (glomerular filtration rate, differential renal function of the affected kidney, obstructive pattern) parameters were also taken into consideration. Some variables were also made dichotomous (pelvic diameter < or > 15 mm, parenchymal thickness < or > 5 mm, differential renal function < or > 40%). Statistical correlation was sought with parametric and non-parametric tests. No correlation whatsoever was found between the two groups for any of the parameters under consideration, so that any attempt at logistical regression analysis failed. None of the currently adopted diagnostic tests can be used to indicate which renal units will benefit from surgery through an improved renal function. The presence or absence of clinical symptoms does not appear to affect renal function either. There is evidence that parents should be provided with such information when giving their informed consent to pyeloplasty.