Role of a Preoperative Catheter Regimen in Achieving Early Primary Endoscopic Valve Ablation in Neonates with Posterior Urethral Valves

Abstract

Purpose: Primary valve ablation is preferred to vesicostomy in the initial management of posterior urethral valves. However, some neonates have a prohibitively small urethra. We describe our experience with a preoperative urethral catheter regimen to enhance the likelihood of neonatal valve ablation.

Materials and methods: We performed a retrospective review of 126 neonates with posterior urethral valves treated between 2003 and 2019 with valve ablation prior to 10 weeks of age. The preoperative indwelling catheter either was gradually upsized to an 8Fr (progressive urethral dilation), was not upsized (nondilated) or was initially larger bore (8Fr only). The primary outcome was the ability to perform primary ablation by neonatal resectoscope. The secondary objective was to establish the parameters for considering progressive urethral dilation as well as its associated risks.

Results: Overall 97% could be ablated. The progressive urethral dilation group had the lowest mean weight (p <0.001). Only a larger catheter at the time of ablation was significantly associated with feasible ablation (p <0.001) and not urethral dilation, the infant's weight or his gestational age. Progressive urethral dilation was associated with a longer duration of catheterization as well as double the rate of febrile urinary tract infections (8.5%) over the nondilated group (3.6%).

Conclusions: A much higher rate of primary ablation is feasible (97%) than previously reported (82%). More important than the infant's weight is whether a 6Fr to 8Fr catheter is in place at ablation. If an initial 6Fr to 8Fr catheter cannot be placed, urethral dilation to 8Fr should be performed before attempting ablation. This is both a technique and preoperative assessment that is useful for operative planning.

Keywords: ablation techniques; urethra; urethral obstruction.