Megaureter and Other Congenital Ureteral Anomalies Treatment & Management

Increasing experience shows that a considerable number of children with VUR or megaureters without reflux or obstruction may demonstrate improved renal function on radiography, without surgical intervention. Nonoperative treatment mandates close follow-up care in patients with VUR or nonobstructed/nonrefluxing megaureters.

Nonoperative management of VUR and nonobstructed primary megaureter includes antimicrobial suppression, treatment of voiding dysfunction, and regular imaging studies to assess renal growth, renal scarring, and possible resolution of pathology.

The need for antibiotic prophylaxis in all patients with VUR has been brought into question. Current recommendations include low-dose antibiotic suppression in children younger than 1 year with VUR and a history of febrile UTI, based on greater morbidity from recurrent UTI in this population.^[3] Use of antibiotic prophylaxis in older children with VUR should be made on an individualized basis; however, the use of prophylaxis would appear to be the most beneficial in those with grade 3 or greater reflux, girls, those with a significant history of recurrent febrile UTIs, and/or those with bowel or bladder dysfunction.

In the absence of obstruction and/or VUR, ureteral duplication anomalies require no specific therapy.

Megaureter

Megaureter secondary to severe VUR or obstruction is usually managed with ureteral reimplantation. Reimplantation techniques are similar to those used for correcting primary VUR. The megaureter can be mobilized via an intravesical, extravesical, or combined approach. Most megaureters will require tapering. The ureteral caliber can be reduced by excising the distal redundant ureter (Hendren technique^[4] ) or plication (Kalicinski technique, Starr technique^[5] ) to achieve a satisfactory antireflux mechanism. Occasionally, the function of the kidney drained by a megaureter is severely impaired, and nephroureterectomy may be necessary. There have been reports of obstructive megaureters treated successfully by endoscopic dilation.

Ureteral duplication

Ureteral duplication alone requires no specific intervention. Duplication anomalies with associated pathology, such as VUR or obstruction, require appropriate medical therapy and possible surgical correction.

Ureteral ectopia

• Single system: If an ectopic ureter is associated with a single system and the kidney is severely dysplastic or poorly functioning, the recommended treatment is nephrectomy with partial or total ureterectomy. If the involved kidney is functioning satisfactorily, the recommended treatment is ureteral reimplantation. In rare instances of bilateral single-system ectopic ureters, when the bladder capacity is actually adequate for urination, bilateral ureteral reimplantation is performed; if the bladder neck is poorly developed in association with the ureteral ectopia, bladder neck reconstruction (Young-Dees-Leadbetter bladder neck plasty) may be necessary.
• Duplex system: Treatment depends on the function of the involved upper pole and whether VUR is present. If function is adequate, a ureteropyelostomy (upper-pole ureter to lower-pole renal pelvis) or ureteroureterostomy (upper-pole ureter to lower-pole ureter) is performed if no VUR is noted in the lower pole ureter. In patients with a functioning upper-pole system and coexisting lower-pole VUR, a common sheath ureteral reimplantation is performed. If the upper-pole moiety is nonfunctional, a partial nephroureterectomy is performed and the upper-pole ureter is removed to the pelvic brim. If patients have coexisting upper-pole VUR, the ureteral stump should be ligated to prevent reflux of urine into the retroperitoneum.

Ureterocele

Treatment of the ureterocele is based upon relief of obstruction. Endoscopic puncture may be used in cases in which urgent decompression is required (eg, urosepsis, severe compromise in renal function), or it may be used as definitive therapy in the case of a single-system intravesical ureterocele. Endoscopic decompression in cases of ectopic ureterocele constitutes definitive treatment in only 10-40% as there is frequently associated VUR, which often requires subsequent surgical correction.

Options for open surgical reconstruction include ureteropyelostomy, ureteroureterostomy, excision of ureterocele and ureteral reimplantation, or upper-pole heminephrectomy with partial ureterectomy and ureterocele decompression. In patients with a single-system ureterocele and an associated nonfunctioning kidney, a nephroureterectomy may be performed.

Vesicoureteral reflux

Because the submucosal ureter tends to lengthen with age, the ratio of tunnel length to ureteral diameter also increases, and the propensity for reflux may disappear. Successful nonoperative management of VUR requires preventing renal damage from pyelonephritis and has involved the use of continuous antibiotic prophylaxis and treating bowel or bladder dysfunction.

Dextranomer hyaluronic acid copolymer is a bulking agent for endoscopic treatment of VUR. Endoscopic treatment results in reflux resolution or downgrading in most patients, with long-term success rates of approximately 60-70%.^[6] Although not as effective as open ureteral reimplantation, endoscopic correction of VUR offers a minimally invasive, outpatient procedure with a low risk of complications.

In general, ureteral reimplantation has excellent results (>95% success rate). Although the transvesical approach is commonly used, the extravesical approach (detrusorrhaphy) preserves the integrity of the bladder lumen and does not require a ureteral anastomosis. Extravesical reimplantation has been shown to decrease postoperative hematuria, minimize bladder spasms, reduce the need for urethral catheter, and shorten hospital stay. Of note, transient cases of urinary retention have been reported with bilateral extravesical ureteral reimplant. Although open ureteral reimplantation remains the gold standard, minimally invasive techniques (robotic assisted ureteral reimplantation) have demonstrated comparable success rates.^[7]

The goals of the preoperative evaluation of the possible ureteral anomaly are as follows:

• Detailed delineation of upper and lower urinary tract anatomy
• Assessment of differential function of each of the renal moieties
• Detection of the presence of anatomical or functional obstruction or VUR
• Evaluation of bladder function

The principles of successful ureteral reconstruction are as follows:

• Adequate ureteral exposure and mobilization with meticulous preservation of blood supply
• Gentle handling of the tissue, and protection of the contralateral ureteral orifice
• With ureteral reimplantation, a submucosal tunnel with a length-to-ureteral diameter ratio of 5:1 to create an adequate valve mechanism to prevent VUR

Follow-up care may include renal ultrasound to assess renal growth and the presence of renal scarring or hydronephrosis. Suppressive antibiotics are discontinued during the postoperative period. Parents are counseled that urinalysis and urine culture are still indicated if their child becomes symptomatic (eg, dysuria, flank pain, hematuria) and that, although their child is at a reduced risk for kidney infection, bladder infections may still occur. Periodic evaluation of voiding symptoms and bladder function may also be included in follow-up care.

Complications of ureteral reimplantation are uncommon. The most common technical complications are ureteral obstruction, persistent reflux, and diverticula formation. A renal ultrasound should be obtained following surgical correction of VUR to assess for obstruction. Because of the very high success rate of open ureteral reimplantation, a postoperative VCUG is performed only in select cases.

Ureteral reimplantation for megaureter repair is a very safe, reproducible, and successful procedure. The major complications are the development of ureteral obstruction (2-5%) or VUR (approximately 10%). Ureteral obstruction is most likely the result of ureteral ischemia and subsequent fibrosis of an excisionally tapered segment. Initial management of this complication is percutaneous or endoscopic dilatation and stenting of the stricture, but many such instances ultimately require open surgical revision. If postoperative VUR is encountered, a reasonable treatment option is observation and antibiotic prophylaxis because many reflux cases resolve spontaneously.

In addition, VUR is more likely to recur following reimplantation in cases in which bladder pressures are elevated (eg, patients with untreated neuropathic bladders or voiding dysfunction). Treatment of bladder/bowel dysfunction is indicated, preferably prior to surgical intervention of VUR careful assessment of voiding symptoms and a low threshold for urodynamic studies are crucial in the evaluation of patients with recurrent VUR.

The outcome of ureteral anomalies chiefly depends on the presence or absence of obstruction and/or infection, and associated renal injury. In the absence of these, no treatment may be necessary, especially in the case of isolated ureteral duplication anomalies, low-grade VUR, a small orthotopic ureterocele, or a nonobstructed, nonrefluxing primary megaureter. With respect to primary megaureters, as in the case of VUR, spontaneous resolution is common. In the case of the obstructed primary megaureter, spontaneous resolution is less likely to occur; however, a study reported a 70% spontaneous regression.^[8]

Cases of high-grade VUR are less likely to spontaneously resolve and more likely to put the kidney at risk of scarring due to pyelonephritis. Prevention of infection is essential to minimize the risk of renal damage; therefore, continuous antibiotic prophylaxis is usually used in children with high-grade VUR while awaiting spontaneous resolution. In the case of obstructive ureteroceles, treatment to relieve obstruction optimizes preservation of renal function as chronic obstruction can lead to renal deterioration.

Antibiotic prophylaxis for all children with VUR remains controversial, although it is recommended in children younger than one year with a history of febrile UTI or grade III reflux or higher. Bowel and bladder dysfunction are often associated with VUR and increase the risk of pyelonephritis, so should be evaluated and treated aggressively in children with VUR.

Robotic-assisted ureteral reimplantation has gained popularity and will continue to evolve with time, although open ureteral reimplantation currently remains the criterion standard for surgical management of VUR. The best approach to the initial treatment of an ecoptic ureterocele without reflux by endoscopic decompression or upper pole heminephrectomy continues to be debated.