Comparing outcome of pyeloplasty in excessively and non excessively dilated renal pelvis in pediatric population: a prospective comparative study

Background Despite the high success of dismembered pyeloplasty (Anderson–Hynes) for the management of pelvi-ureteric junction obstruction (PUJO), outcomes in children with excessively dilated renal pelvis remain insufficiently defined clinically. We aimed at evaluating the functional outcome of dismembered pyeloplasty in an excessively dilated renal pelvis-defined as Antero-posterior diameter of renal pelvis more than 50 mm- and comparing the results with those of non-excessively dilated renal pelvis in the pediatric population. Methods This prospective comparative study, conducted at a tertiary-care pediatric hospital, included 43 pediatric cases presenting with PUJO, with 46 renal units indicated for surgical intervention. Patients were divided into: Group 1: included 23 cases with 23 renal units with non-excessively dilated renal pelvis, and Group 2: included 20 patients with 23 renal units with excessively dilated renal pelvis, both underwent Dismembered pyeloplasty. Primary outcomes were defined as resolution of clinical symptoms, improvement of anteroposterior pelvic diameter (APD), and parenchymal thickness (PT). Secondary outcome included absence of postoperative complications as graded according to Clavien-Dindo classification, functional improvement on renal nuclear scan, and the rate of secondary surgical intervention. Results Male: female ratio was 3.8:1, mean age at presentation for group 1 was 11.8 ± 12.9 months vs. 16.5 ± 14.2 months for group 2 ( p = 0.242). Preoperative anteroposterior pelvic diameter (APD), operative time, and reduction rate were significantly higher in Group 2 compared with Group 1 ( P < 0.05). Postoperative APD of Group 2 remained significantly higher at 6 and 12 months postoperatively ( P < 0.005), whereas Group 1 showed a marked reduction over time. No significant differences were observed between groups in Parenchymal Thickness (PT) at any follow-up point. Preoperative APD, age at presentation, and preoperative isolated glomerular filtration rate (GFR) were significantly associated with surgical success ( P < 0.005), while age at surgery, preoperative creatinine level, and PT were not. Group 2 showed a significantly lower success rate and a higher incidence of postoperative complications in the form of postoperative fever (30.4%), and the need for Secondary surgical intervention under general anaesthesia (Clavien–Dindo Grade IIIb) (21.7%). Conclusions Pyeloplasty is safe and highly effective for pediatric pelvi-ureteric junction obstruction. However, pediatric patients presenting with excessively dilated renal pelvises (APD > 50 mm) exhibit a higher rate of postoperative complications and secondary interventions compared to non-excessively dilated cases. Integrating extensive excisional reduction pyeloplasty into the surgical protocol for excessively dilated units restores upper tract anatomy and yields high overall success.