Ureteric Duplication

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INTRODUCTION

Ureteric duplication is one of the most common mal- formations of the urinary tract. In many patients it is discovered as an incidental finding without clinical symptoms and does not require any surgical correction. With the advent of prenatal ultrasonography an increasing number of uropathies are discovered be- fore clinical manifestations. Duplication can be associated with other anomalies, such as reflux, mega- ureter, ectopic ureter, and ureterocele.

Duplication can be complete or partial, when the two segments unite with one another somewhere between the renal pelvis and the intramural ureter above the bladder.

Bifid ureters (incomplete duplication) may join at any level from the bladder to the ureteropelvic junction. The presence of a bifid ureter does not predis- pose toward vesicoureteric reflux, and surgical correction is based on the same indications as for a single refluxing ureter.

Complete duplication may be associated with vesicoureteric reflux, ectopic ureters or ureterocele.

Two operative possibilities exist for reflux in ureteric duplication, depending on whether reflux affects the lower pole ureter or both ureters.

The therapeutic considerations for surgical correction of reflux associated with duplication are similar to those for reflux in a single ureter, though spon- taneous resolution is less likely to occur with growth of the child when reflux involves the lower pole only.

When reflux affects only the lower pole and the pa- tient has severe pyelonephretic lesions as demon- strated by ultrasound and nuclear scintigraphy, heminephrectomy should be considered. Removal of the remaining ureteric stump is rarely necessary.

An ectopic ureter exists when the ureteric opening is located outside the bladder. In approximately 80%

of cases it is associated with duplication, particularly in girls. In boys, however, the ectopic ureter is more often a single ureter than related to a duplex system.

Duplication in boys may be observed with a relative- ly high ectopic opening of the ureter (bladderneck, urethra). The upper pole parenchyma related to the ectopic ureter in a duplex kidney is commonly of lit- tle functional value, and dysplastic lesions are usual-

ly present. It is therefore pointless to try to preserve a structure that does not contribute to total renal function and is likely to maintain a source of infection.

Ureterocele associated with duplication is a rather common anomaly in pediatric always related to the upper pole, and the position of the ureteric orifice al- lows for distinction between an intravesical ureterocele and an ectopic (extravesical) ureterocele. In the intravesical form, the opening of the ureterocele is located between the normal position of the ureteric orifice and the bladder neck. In the extravesical ureterocele, the opening is located at the bladder neck or in the urethra. This anatomic distinction is important because both presentation and treatment of the anomalies are different. Thanks to prenatal diagnosis, asymptomatic ureteroceles are being encoun- tered more often, allowing appropriate evaluation.

Management remains however controversial but leads to be less aggressive than with clinical presentation and single extrapolation from clinical presentation with infection should not be systematic since a more conservative attitude might be better appropriate. There is a clear and unfortunate lack of more evidence based attitudes.

The main goals in the treatment of ureterocele are control of infection, protection of normal ipsilateral and contralateral renal units, preservation of renal function, facilitation of subsequent surgery and the maintenance of continence.

There is no unanimity on how to manage surgical- ly complex ureteroceles in children; all points of view have certain advantages and drawbacks. For the surgeon who is not familiar with the condition and sel- dom operates on infants, upper pole nephrectomy alone is the safest initial procedure. In neonates with sepsis and in poor general condition, preliminary decompression may be necessary and simple endoscopic incision of the ureterocele is advisable, because these neonates are poor candidates for a major procedure. In neonates with an uninfected ureterocele discovered by prenatal ultrasonography, mini- mal endoscopic meatotomy may have merit in allowing recovery of satisfactory renal function. A even more conservative approach may be considered fol- Claude C. Schulman

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Claude C. Schulman 516

Figure 49.1, 49.2

Through a Pfannenstiel incision, the bladder is opened and a self-retaining retractor is placed. Intra- vesical and extravesical dissection will liberate the ureters, which sould be sectioned above their point of junction, the common trunk is excised and both ureters are re-implanted as a single unit in a common submucosal tunnel using the classic antireflux procedure. Stenting of both ureters is usual for a few days, with bladder drainage.

As both ureters are bound together in a common sheath at their lower end in complete ureteric duplication they are treated en bloc as a single unit as the two elements may be devascularized in an attempt to separate them.

Any of the procedures to correct reflux may be used, either by intravesical advancement or by extravesical ureteroneocystostomy. The classic Cohen re- implantation is most widely used.

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lowing anteral diagnosis in the presence of dysplastic upper pole without significant obstruction and in the absence of clinical problems. A wait and see policy can be considered like for single dysplastic kidneys which tend to involute without further clinical problems. There is no evidence that in such cases surgical treatment should be systematic. For older children in good general condition, the experienced surgeon should consider a total, single-stage complete recon- struction. Very occasionally, total nephroureterecto- my is indicated when the lower pole is also destroyed by obstruction or reflux. Alternatively, complete excision of an ectopic ureterocele with re-implantation of the lower pole ureter and sometimes of the contralateral ureter may be performed. Upper pole nephrou- reterectomy is performed first, during the same operative session, through a retroperitoneal flank incision. Cautious extravesical dissection separates both ureters; great care must be taken to preserve the per- iureteric adventitia of the lower pole ureter with its blood supply. There is a definite need for more evidence-based attitude.

Figure 49.3

Procedures as ureteropyelostomy should only be considered in a solitary kidney or when both kidneys are damaged. A flank incision is made, the kidney is left in situ and the ureters are liberated from the renal sinus up to their point of junction. The dilated upper pole ureter is excised exactly where it opens into the lower pole ureter. It is important not to leave

any ureters that could act as a diverticulum. The ex- cess abnormal ureter is removed and the incision in the remaining ureter is closed with interrupted poly- glycolic acid sutures. A large end-to-side anastomo- sis between the upper ureter and the renal pelvis is created so that the end result mimics a bifid renal pelvis without functional obstruction.

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Figure 49.1 Figure 49.2

Figure 49.3

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Figure 49.4, 49.5

Heminephrectomy is performed via a subcostal lum- botomy or through the last intercostals space and the atrophied and dysplastic upper pole with the corre- sponding dilated ureters is removed. The renal capsule on the upper pole is incised to be used later to suture over the renal parenchyma. As vascularization of the upper pole often varies and some arterial branches are likely to separate from the main artery close to the renal sinus, it may sometimes be hazard-

ous to clamp and ligate these vessels because this could cause ischaemic lesions of the remaining parenchyma.

A clear demarcation is often visible between the destroyed upper pole and normal lower pole and it is preferable to follow the cleavage plane, which is less vascularized, and to achieve haemostasis as necessary.

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Figure 49.6

The procedure is completed by suturing the parenchyma of the remaining lower pole and then closing the capsule.

It is advisable to undertake simple nephropexy of the lower pole, for example, by fixing it to the poste-

rior muscular wall, to avoid its rotation around a long pedicle that has been stretched severely because of ureteric dilatation.

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Figure 49.4 Figure 49.5

Figure 49.6

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Figure 49.7

Thus, a duplex system ureterocele is when the ureter- ocele is attached to the upper pole ureter of a com- pletely duplicated collecting system and a single-sys- tem ureterocele is when the ureterocele is attached to a single ureters draining the kidney. Regarding the location and extension, if the ureterocele and its orifice are located entirely within the bladder, the term intravesical is used. If the ureterocele and its orifice extends beyond the trigone to the bladder neck or outside of the bladder to involve the urethra the term ectopic is applied. Intravesical ureteroceles are usual- ly associated with single systems, whereas ectopic ureteroceles are usually associated with the upper pole ureters of a duplex-system.

The management of the orthotopic ureterocele is straightforward. One makes an endoscopic puncture

using a pure cutting current at the distal aspect of the ureterocele just above its junction with bladder. As the Bugbee electrode is passed through the ureterocele wall, it may be moved slightly laterally in either direction to enlarge the opening. One can readily see the ureterocele deflate. In some cases, manual compression of the flank over the hydronephrotic moiety is helpful in distending the ureterocele prior to puncture, and this may demonstrate a jet urine following decompression.

For the ectopic ureterocele, a similar technique is used as the puncture is made at the base of the ureterocele at its junction with bladder wall in a clearly intravesical location. Because the ureterocele may ex- tend distally beyond bladder neck, the location of the incision must be very clearly visualized.

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Figure 49.8, 49.9

If reflux persists after endoscopic puncture of ureterocele, the treatment options are either endoscopic correction of reflux or open surgical re-implantation of duplex ureters.

Ureteric dilatation is usually moderate and treatment is similar to that used for simple ureterocele with a single ureters, consisting of excision of the ureterocele with common sheath ureteric re-implantation.

The bladder is opened and a circumferential incision is made at the base of the ureterocele. Previous

injection of saline into the ureterocele is helpful for its dissection from the trigone.

After excision of the ureterocele, the hiatus may be quite large and it is closed, treating the two ureters as a single unit.

The ureters are re-implanted, using one of the advancement techniques or the Politano-Leadbetter procedure. A transverse submucosal tunnel, as is used in the Cohen re-implantation procedure, is il- lustrated.

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Figure 49.7

Figure 49.8 Figure 49.9

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CONCLUSION

Duplication of the renal pelvis and ureters is the commonest anomaly of the upper urinary tract. It occurs in approximately 0.8% of the population and

in 1.8–4.2% of pyelograms. Commonly these are asymptomatic. However, they can challenge the diag- nostic acumen with a wide variety of manifestations.

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SELECTED BIBLIOGRAPHY

Diamond DA, Retek AB (2002) Endoscopic surgery of urethral valves and ureteroceles. In: Frank JD, Gearhart JP, Synder III HM (eds) Operative pediatric urology. Churchill Living- stone, London, pp 31–37

Chertin B, De Caluwe D, Puri P (2003) Is primary endoscopic puncture of ureterocele a long-term effective procedure. J Pediatr Surg 38 : 116–119

Frey P, Mendoza-Sagron M, Meyrat BJ (2003) Ureterocele in the newborn. Arnold, London, pp 845–854

Schulman CC (1995) Ureteric duplications. In: Spitz L, Coran AG (eds) Pediatric surgery. Chapman & Hall, London, pp 655–665