(From the November 2014 Research Now)
Children with duplex anomalies of the kidneys may benefit from a more conservative surgical treatment than partial organ removal, according to a study by urologists at Nationwide Children’s Hospital. Even when the upper portion of the duplex kidney functions poorly, their findings indicate that ureteroureterostomy (UU) may effectively correct ureteral blockages — sparing children a riskier operation without negatively affecting the lower kidney.
Believed to occur in as many as 1 percent of all births, duplex renal anomalies often involve a duplication of the ureters and a near doubling in size of at least one kidney. In many cases, having two ureters running from a single kidney unit to the bladder in parallel may not cause any problems. But when the congenital abnormality does cause swelling of the kidney or a blockage in a ureter, the problem usually requires surgery to correct.
UU is a relatively simple operation that involves the connection of the two parallel ureters to form a Y-shaped drainage vessel, allowing blockages at the bottom of one tube to be negated by removing the second connection to the bladder. However, if the size of the ureters to be connected varies dramatically or if the upper portion of the kidney has poor or no function, tradition dictates removal of the malfunctioning portion of the kidney and its entire attached ureter. UU leaves the entire duplex kidney in place, so some urologists have expressed concerns about the risk of high blood pressure and damage to the lower portion of the kidney — problems that are theoretically avoided with the more invasive removal of the upper kidney.
“There was no data to back up those worries, though,” says Daryl McLeod, MD, MPH, urologist at Nationwide Children’s and first author on the paper, which was published in the Journal of Pediatric Urology. “We thought it would be safer to avoid surgery on the kidney due to the higher risk of bleeding or affecting the large blood vessels that feed the healthy kidney portion, so we performed UUs and left the upper kidneys in place.”
The surgical urology team, led by V. Rama Jayanthi, MD, chief of Urology at Nationwide Children’s, performed UU surgeries on 41 patients with diagnoses of ureterocele, ectopic duplex ureter and ureteral triplication. Median upper kidney function was 17 percent, but all operations left the kidneys in place and simply corrected ureteral blockages with UU. No patients experienced problems with the lower, healthy portion of the kidney in the average postoperative follow-up period of 2.8 years.
Both open and laparoscopic procedures occurred during the study period of seven years. Five of the 41 patients required UU with a simultaneous lower-kidney ureteral reimplantation and only two complications occurred; one patient had a postoperative ureterovesical junction stricture and one had an anastomotic stricture, both of which required reoperation. These complication and reoperation rates appear to be significantly lower than those associated with partial kidney resection, Dr. McLeod says.
Although the team believes long-term follow-up will be critical to determining whether UU truly helps avoid the risk of high blood pressure and damage to the healthy parts of the patients’ kidneys, they believe the early results are encouraging.
“There were no obvious signs of injury to the healthy part of the kidney in any of our patients,” says Dr. McLeod, who also is a clinical instructor of urology at The Ohio State University College of Medicine. “In our experience, the children did very well and we found UU to be a safe and effective technique to address duplex renal anomalies, even when upper kidney function is undetectable and ureters have large size disparities.”
McLeod DJ, Alpert SA, Ural Z, Jayanthi VR. Ureteroureterostomy irrespective of ureteral size or upper pole function: A single center experience. Journal of Pediatric Urology. 2014 June 2. [E-pub ahead of print]