Megaureter and Other Congenital Ureteral Anomalies Treatment & Management

Increasing experience shows that a considerable number of children with vesicoureteral reflux (VUR), or megaureters without reflux or obstruction, may demonstrate improved renal function on follow-up radiography, without surgical intervention. ^{[6, 7]} However, 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. Bowel and bladder dysfunction are often associated with VUR and increase the risk of pyelonephritis, and so should be evaluated and treated aggressively in children with VUR.

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 urinary tract infection (UTI), based on greater morbidity from recurrent UTI in this population. ^[8] 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 one or more of the following risk factors:

• Grade 3 or greater reflux
• Female sex
• A significant history of recurrent febrile UTIs
• Bowel or bladder dysfunction

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

Robotic-assisted ureteral reimplantation has gained popularity and will continue to evolve with time, although open ureteral reimplantation remains the criterion standard for surgical management of VUR. The use of endoscopic injection therapy (EIT) for the treatment of VUR has grown considerably but despite the excellent short-term success rate, increasing reports of complications such as delayed ureteral obstruction and concerns about durability limit the use of EIT. ^[9]  

The presence of an acute UTI, especially with bullous edema of the bladder mucosa, may be a contraindication to definitive reconstruction. Urinary diversion (eg, ureterostomy, vesicostomy) or drainage may be necessary.

The best approach to the initial treatment of an ecoptic ureterocele without reflux (ie, by endoscopic decompression or by upper pole heminephrectomy) continues to be debated.

Megaureter

In megaureter, indications for surgical intervention are as follows:

• Increasing hydroureteronephrosis
• Decrease in function of the involved kidney
• Development of UTI or recurrent pain

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 ^[10] ) or plication (Kalicinski technique, Starr technique ^[11] ) 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.

Laparoscopic-assisted extracorporeal ureteral tapering repair and ureteral extravesical reimplantation has been reported as a safe alternative to open surgery when first-line treatment fails. ^[12]

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

In ureterocele, indications for surgical intervention are as follows:

• Obstruction
• Urosepsis or compromised renal function may necessitate urgent decompression prior to definitive surgical reconstruction.

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% of cases, 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

In VUR, absolute indications for surgical intervention are as follows:

• Progressive renal injury
• Documented failure of renal growth
• Breakthrough pyelonephritis
• Intolerance of or noncompliance with antibiotic suppression
• Parental preference

Relative indications for surgical intervention in VUR are as follows:

• Pubertal age
• High-grade (IV or V) VUR
• Failure to resolve

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%. ^[13] 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. ^[14]

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

Howe and Palmer report that Lich-Gregoir extravesical ureteral reimplantation (EVR) using an inguinal approach can be safely and effectively applied to complex cases (eg, megaureter, duplex ureters). In their report on 28 cases, this approach was successful in 94% of tapered EVR and in 92% of common sheath reimplants, with a mean follow-up of 29.6 months. No postoperative obstructions, urinary leaks, or wound infections occurred. ^[15]

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.

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.