Ureteric stents vs percutaneous nephrostomy for initial urinary drainage in children with obstructive anuria and acute renal failure due to ureteric calculi: a prospective, randomised study.

Objectives: To compare percutaneous nephrostomy (PCN) tube vs JJ ureteric stenting as the initial urinary drainage method in children with obstructive calcular anuria (OCA) and post-renal acute renal failure (ARF) due to bilateral ureteric calculi, to identify the selection criteria for the initial urinary drainage method that will improve urinary drainage, decrease complications and facilitate the subsequent definitive clearance of stones, as this comparison is lacking in the literature.

Patients And Methods: A series of 90 children aged ≤12 years presenting with OCA and ARF due to bilateral ureteric calculi were included from March 2011 to September 2013 at Cairo University Pediatric Hospital in this randomised comparative study. Patients with grade 0-1 hydronephrosis, fever or pyonephrosis were excluded. No patient had any contraindication for either method of drainage. Stable patients (or patients stabilised by dialysis) were randomised (non-blinded, block randomisation, sealed envelope method) into PCN-tube or bilateral JJ-stent groups (45 patients for each group). Initial urinary drainage was performed under general anaesthesia and fluoroscopic guidance. We used 4.8-6 F JJ stents or 6-8 F PCN tubes. The primary outcomes were the safety and efficacy of both groups for the recovery of renal functions. Both groups were compared for operative and imaging times, complications, and the period required for a return to normal serum creatinine levels. The secondary outcomes included the number of subsequent interventions needed for clearance of stones. Additional analysis was done for factors affecting outcome within each group.

Results: All presented patients completed the study with intention-to-treat analysis. There was no significant difference between the PCN-tube and JJ-stent groups for the operative and imaging times, period for return to a normal creatinine level and failure of insertion. There were significantly more complications in the PCN-tube group. The stone size (>2 cm) was the only factor affecting the rates of mucosal complications, operative time and failure of insertion in the JJ-stent group. The degree of hydronephrosis significantly affected the operative time for PCN-tube insertion. Grade 2 hydronephrosis was associated with all cases of insertion failure in the PCN-tube group. The total number of subsequent interventions needed to clear stones was significantly higher in the PCN-tube group, especially in patients with bilateral stones destined for chemolytic dissolution (alkalinisation) or extracorporeal shockwave lithotripsy (ESWL).

Conclusion: We recommend the use of JJ stents for initial urinary drainage for stones that will be subsequently treated with chemolytic dissolution or ESWL, as this will lower the total number of subsequent interventions needed to clear the stones. This is also true for stones destined for ureteroscopy (URS), as JJ-stent insertion will facilitate subsequent URS due to previous ureteric stenting. Mild hydronephrosis will prolong the operative time for PCN-tube insertion and may increase the incidence of insertion failure. We recommend the use of PCN tube if the stone size is >2 cm, as there was a greater risk of possible iatrogenic ureteric injury during stenting with these larger ureteric stones in addition to prolongation of operative time with an increased incidence of failure.