Obstructed Megaureter Treatment & Management
- Author: Robert A Mevorach, MD; Chief Editor: Edward David Kim, MD, FACS more...
In mild cases of obstructed megaureter, physicians may monitor symptoms, perform periodic radiological imaging, and administer antibiotic prophylaxis. With improving or stable renal or ureteral dilatation and continued renal growth, prognosis (over 8 y of follow-up) is excellent.
Megaureters detected in neonates and infants may require drainage for infections that do not respond to antibiotics alone. Additionally, the massively dilated ureter may be decompressed with ureterostomy, refluxing ureteroneocystostomy, pyelostomy, or nephrostomy drainage, which often allows a substantial decrease in ureteral size and greatly reduces ureteral bulk during both tailoring and reimplantation.
The ultimate goals of surgical intervention are to relieve obstruction, to return near-normal function to the collecting system, to create a nonrefluxing vesicoureteral reimplantation, and to preserve renal development without long-term complications. With these goals, the two main surgical approaches are as follows:
Distal ureteral mobilization with resection of the obstructing segment and reimplantation, with or without ureteral tailoring (to ensure a nonrefluxing tunnel)
Extensive tailoring of the ureter from the renal pelvis distally to provide a theoretical benefit for restoring normal peristalsis by reduction of ureteral luminal diameter
In experienced hands, both approaches yield excellent long-term results. Substantive differences are not statistically or clinically apparent.
Patients with voiding dysfunction or significant reflux may benefit from an intravesical ureteral reimplantation. Patients without voiding problems or reflux do equally well from an extravesical approach.
Primary endoureterotomy with stenting has been reported favorably in selected cases in children. In one series, 90% of cases showed improvement, with complete resolution reported in 71%.
In adults, a direct nipple ureteroneocystostomy can be performed. This is technically simpler to perform since the ureters and submucosal tunnels require no tailoring. Limited reports with follow-up of up to 36 months indicate a high success rate with this technique in adults.
Document that patients are free of infection at the time of reconstruction. Blood loss is normally insubstantial, and transfusion is rarely necessary.
The incision is chosen to access the upper ureter, the lower ureter, or the entire ureter. Use intravesical and extravesical dissection, alone or in combination, to mobilize the enlarged ureter.
Take care to preserve the ureteral blood supply, which arises from the aorta, renal artery, gonadal artery, and internal iliac artery, particularly if undertaking extensive tailoring.
Tailoring either can be excisional or can involve varied forms of luminal exclusion and ureteral folding; however, reductions smaller than 10F are not recommended to avoid subsequent stenosis.
Neocystostomy tunnel lengths of 4:1-6:1 are recommended to avert postoperative reflux. Postoperative drains or splints for the ureters are used at the discretion of the surgeon.
Patients remain on antibiotic prophylaxis for months after surgery, until imaging studies or clinical status warrants discontinuation.
Repeated ultrasonography imaging is mandatory to assess whether hydronephrosis and hydroureter improve after surgery. Because the benefit of repeat VCUG and IVU studies is controversial, in the setting of clinical success and ultrasonography improvement, the only recommendation is that the patient and physician agree on the follow-up regimen.
Surgical complications are uncommon and often resolve with observation.
Ipsilateral reflux occurs in 2% of patients. Endoscopic ureteral bulking permits a less-invasive management of this complication when the clinical scenario warrants, and it may all but eliminate open reoperation.
Contralateral reflux occurs in 10% of patients but resolves within 1 year in nearly all cases.
Ureteral obstruction (1%): Early balloon dilation or incision of the meatal stenosis (3 mo) is highly successful. Strongly consider ureteral stenosis of 1.5 cm or greater and devascularized ureteral segments for open reoperation.
Incomplete bladder emptying requiring catheterization (5%): Permanent retention is not reported.
Outcome and Prognosis
Researchers report that surgical outcomes are 98% successful in all major series. Failures were usually in the form of reflux and often occurred with nontapered reimplants. Reoperation with tailoring and repeat neocystostomy is uniformly corrective.
Children who present with infection may experience persistent episodes of UTI. Consider these patients for prolonged prophylaxis to limit the impact of infection on renal growth. Additionally, emphasize UTI surveillance during pregnancy.
Renal function is the key determinant of prognosis because renal dysplasia and infection with associated renal insufficiency are the only expected long-term disabilities associated with primary obstructed megaureter.
Future and Controversies
As with all reconstructive procedures, the belief that recapitulation of anatomy is necessary to achieve excellent functional results is tested continually by the desire to minimize the extent and duration of surgical invasion. When patients are well-served, finding fault with either approach is difficult.
The next wave of interest will arise from the growing trend toward minimally invasive surgery and the application of improved laparoscopic and robotic techniques to reconstructive pediatric urology.
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