Residual PUV after primary ablation can be responsible for the persistence of urinary symptoms and worsening of renal function in children. This study aims to determine the impact of repeat cystoscopy and subsequent re-ablation of residual PUVs using changes in serum creatinine, uroflowmetry, and ultrasonography.

From Apr 2022 to Aug 2023, a study was conducted at the Pediatric Urology Division of BSMMU in Dhaka involving 74 patients with posterior urethral valves. At three months post-diagnosis, 28 patients (37.83%) displayed symptoms, including weak stream (39.3%), straining (10.7%), dribbling (25%), and recurrent fever (3.6%). Among them, 22 had no obstructive remnant leaflets, while 6 (21.4%) did. Serum creatinine levels, Qmax and ultrasound measurements were recorded before valve ablation and at the three-month follow-up. Statistical analysis was performed using SPSS version 26, with a p-value of less than 0.05 considered significant. The study received approval from the institutional ethical committee prior to commencement.

The median age for primary valve ablation was seven years (median [IQR] 7.0 [2.0, 10.7]). Repeat cystoscopy in 37.83% of patients showed a 21.4% prevalence of residual valves. Before the procedure, the mean serum creatinine level was 0.69 mg/dL, with 75% of patients having elevated levels. Significant improvement in creatinine was observed after primary ablation, dropping to 0.6 mg/dL (p = 0.0001), but only minimal improvement was noted after re-ablation (0.57 mg/dL, p = 0.68). Preoperatively, the median maximum flow rate (Qmax) and post-void residual (PVR) were 7.7 and 31.0, respectively, improving to 11.2 and 25.0 at three months. Greater dilation was observed in the left renal units (mean: 13.4 mm) compared to the right (mean: 11.9 mm). The left renal unit showed significant improvement after both ablations (p = 0.04), while the right renal unit improved without statistical significance (p = 0.14 and p = 0.29). In summary, elevated serum creatinine, low Qmax, high PVR, and hydroureteronephrosis were significantly associated with residual valves. Early resolution of obstruction leads to better outcomes.

The prevalence of residual posterior urethral valves after primary ablation was 21.4%, with an improvement in the trend of hydronephrosis and serum creatinine after re-ablation of residual valves. Repeat cystoscopy is therefore effective in detecting residual valves and has the added benefit of being both diagnostic and therapeutic.