Exploring the Role for Endoscopic Balloon Dilation in Children with Severe Primary Obstructive Megaureter
John Jung, BS, Cayde Ritchie, MD, Akin Amasyali, MD, David A. Chamberlin, MD, Joshua D. Chamberlin, MD.
Loma Linda University, Loma Linda, CA, USA.
BACKGROUND: Primary obstructive megaureter (POM) may lead to worsening renal function and UTIs. While up to 80% of megaureter may resolve spontaneously, ureteral reimplantation is often required in severe cases. With improved and miniaturized technology, endoscopic treatment with balloon dilation has been shown to offer a less invasive treatment option in children. We aim to assess the effectiveness of treating severe POM with high pressure balloon dilation.
METHODS: A retrospective review was performed on all patients who underwent ureteral balloon dilation for POM between March 2020 and December 2021 at a single institution. Inclusion criteria were age less than 18 years and presence of POM, defined as distal ureteral diameter greater than 7 mm and an obstructive pattern on Lasix renogram or retrograde pyelogram. Indications for endoscopic intervention included recurrent urinary tract infection (UTI), increase in Society of Fetal Urology (SFU) grade of hydronephrosis, or worsening renal function on renogram. Endoscopic intervention consisted of ureteral balloon dilation under general anesthesia, utilizing a 15Fr balloon and two cycles of dilation to 20 atm of pressure. Two double J ureteral stents were placed at the completion of the procedure and removed after eight weeks. Renal/bladder US was performed every 3-6 months following dilation. Primary outcomes were SFU grade of hydronephrosis, AP diameter of the renal pelvis, and diameter of the distal ureter. Secondary outcomes were rates of postoperative UTI and subsequent ureteral reimplantation. Statistical analysis was performed using Wilcoxin signed-rank test and paired samples t test, with significance defined as p<0.05.
RESULTS: Our cohort consisted of eight patients, two female and six male, with a mean age of 6.5 years (0.4-16.3 years). Endoscopic balloon dilation was performed on a total of nine ureters. Of those with unilateral POM, five were left-sided and two right-sided. Average duration of follow-up was 11.7 months (5-21 months), with no patients lost and no immediate postoperative complications noted. Balloon dilation achieved a statistically significant improvement in SFU grade of hydronephrosis (p=0.039). AP diameter of the renal pelvis improved from 18.2 mm to 8.1 mm, while distal ureteral diameter improved from 13 mm to 3.7 mm (p=0.008 and 0.002, respectively). No patients developed UTI after balloon dilation. Eight of nine ureters (89%) responded to endoscopic management alone and required no further surgical intervention. A six-year-old patient who presented with SFU grade 4 hydronephrosis and an AP diameter of 35 mm required subsequent ureteral reimplant in the setting of failed dilation, given persistent high-grade hydronephrosis and declining differential function on diuretic renogram.
Ureteral balloon dilation improves obstructive parameters on ultrasound and may reduce the need for ureteral reimplantation in children with severe primary obstructive megaureter. Further studies are needed to assess long-term clinical response and identify risk factors for endoscopic management failure.
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