Timothy Boswell, M.D., is one of the nation’s experts on primary obstructive megaureter treatment.
For about 80% of infants with primary obstructive megaureter (POM)—a relatively rare congenital condition in which the ureter is abnormally narrow where it enters the bladder, hindering urine flow—the problem resolves without treatment as the baby grows. For the rest, open surgery has long been the standard approach.
Children’s of Alabama pediatric urologist Timothy Boswell, M.D., is trying to change that. Inspired by European research on, and relatively widespread use of, a minimally invasive technique called high-pressure balloon dilation (HPBD) on children with POM, Boswell is leading the charge to make the option more common in the United States. By doing so, he hopes to minimize pain and other surgical complications for these children.
He and Children’s colleagues have been offering this minimally invasive treatment to the small number of patients needing intervention for POM. HPBD is an endoscopic technique that uses a high-pressure balloon to stretch the narrowed section of the ureter, and it can be a highly successful first-line intervention.
Open reconstructive surgery, called ureteral reimplantation, involves removing the narrow segment of the ureter and reattaching it to the bladder so urine can flow freely. An interim procedure called a ureterostomy can redirect the ureter to a stoma in the abdomen, allowing urine to bypass the bladder and drain directly into a child’s diaper. A ureterostomy eventually has to be reversed, and the ureter reimplanted.
Some type of intervention becomes necessary when children with POM experience recurrent urinary tract infections, kidney or ureteral stones, pain due to the obstruction, or worsening dilation with decreasing renal function.
“Open surgery involves a several-centimeter incision, pain, and staying in the hospital at least one night, and it’s challenging to do in babies under 1 year old,” said Boswell, who’s also an assistant professor of pediatric urology at University of Alabama at Birmingham (UAB). “But it has a greater than 95% success rate.”
However, Boswell authored a February 2024 study in the Journal of Pediatric Urology that suggested that HPBD is a promising alternative. Evaluating the outcomes of using HPBD in 15 infants under 1 year old with progressive or symptomatic POM and tracking participants for an average of 2.9 years, he and his colleagues found the minimally invasive approach to be successful in 80% of cases, sparing most of the babies from subsequent invasive open surgeries.
Because no incisions are involved, HPBD is potentially safer than open surgery and can be done in younger babies, Boswell notes. “As of the 2010s, only a couple of centers in the United States were doing it,” he said. “We’ve been doing it at Children’s since 2023.”
Boswell, who spoke on the topic at the American Academy of Pediatrics Section on Urology in September 2025 and continues to publish papers, hopes more institutions will consider HPBD for children with POM. He also wants to spearhead research that would directly compare the open and minimally invasive approaches for a clearer picture of the pros and cons.
“We know we can do this procedure without needing an incision, but there have never actually been good comparative studies,” Boswell said. “I hope pediatric urologists across the country and world can band together to deliver well-designed studies to see what’s best for patients.”