Ureteral anomalies

Ureteral anomalies are a relatively common disease of the genitourinary system. They account for 13.4% of kidney and ureteral malformations.

The classification of ureteral anomalies is based on such features as their number, position, shape and structure. Today, the classification adopted at the 2nd All-Union Congress of Urologists in 1978 is generally accepted:

• anomalies in the number of kidneys (aplasia, doubling, tripling, etc.);
• anomalies of the position of the kidneys (retroval ureter, retroileal ureter, ectopia of the ureteral orifice);
• anomalies in the shape of the kidneys (corkscrew-shaped, annular ureter);
• renal structural anomalies (renal hypoplasia, neuromuscular dysplasia, including achalasia, megaureter, hydroureteronephrosis, diverticulum valves, ureterocele).

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Forms

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Anomalies in the number of ureters

Aplasia (agenesis) of the ureter is an extremely rare anomaly. Bilateral anomaly is usually combined with bilateral renal agenesis, less often - with bilateral multicystic kidney, it is incompatible with life.

Ureteral duplication is the most common congenital anomaly of the urinary tract. In this case, one ureter collects urine from the upper half of the kidney, and the other from the lower. Typically, the upper half is smaller and consists on average of only two or three calyces. Ureteral duplication can be complete (ureter duplex) or incomplete (ureter fissus). Incomplete ureter duplication occurs when the mesonephric duct (before fusion with the metanephrogenic blastema) divides prematurely into branches. This division can begin in the most distal or most proximal parts of the ureter.

Complete duplication occurs due to the formation of two mesonephros ducts on one side, directed to the metanephrogenic blastema. According to the Meyer-Weigert law, the ureter from the upper half will enter the bladder lower and more medially (ectopic ureter) relative to the ureter draining the lower half (orthotopic ureter). When duplicating, both ureters usually pass in one fascial bed. This type of anomaly is described in detail in the section on anomalies in the number of kidneys. Triplication of ureters is extremely rare.

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Anomalies of the position of the ureters

Retrocaval ureter is a relatively rare malformation (0.21%), in which the right ureter (upper and partially middle third) spirally encircles the inferior vena cava at the level of L3-4. Retroiliac ureter is an extremely rare anomaly, in which the ureter is located behind the common or external iliac vein. Excretory urography usually reveals a J-shaped bend of the upper third of the ureter due to obstruction in the retrocaval segment, and only retrograde ureterography can detect an S-shaped bend. Cavography does not provide additional information, CT and MRI also help in detecting uro-vasal conflict. If necessary, CT can be an alternative to retrograde ureterography. Spiral CT allows visualization of the course of the ureter. These anomalies are manifested by the development of ureterohydronephrosis. The treatment is aimed at restoring urodynamics by disabling the retrocaval or retroileal portion of the ureter. It is performed both openly and laparoscopically.

Ectopia of the ureteral orifice is an anomaly in the location of one or two ureteral openings in the bladder or extravesically.

M.E. Campbell (1970) found ectopia of the orifice in 10 cases during autopsy of 19,046 children (0.053%). In 80% of cases, ectopia is associated with duplication of the ureter. The clinical picture depends on the place of entry of the ectopic orifice and the state of the UUT. The entry of the ureteral orifice into the urethra, vagina, uterus, external female genitalia is accompanied by uncontrolled leakage of urine against the background of preserved urination. The entry of the ureter into the bladder above the sphincter of the urethra, into the seminal vesicle, vas deferens, intestine is not accompanied by urine leakage and may not have characteristic symptoms or may not be accompanied by long-term inflammatory diseases of the internal genital organs.

In most cases, ectopia is associated with ureterohydronephrosis. It should be noted that ultrasound and excretory urography allow diagnosing only ureterohydronephrosis. MSCT and MRI help establish a diagnosis even with a sharp decrease in kidney function. Surgical treatment. Ureterocystostomy for stricture of the terminal ureter. Hemi- or nephrectomy for terminal changes in the kidney and UUT.

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Anomalies of the structure and shape of the ureters

Corkscrew or ring ureter is an extremely rare anomaly. M.E. Campbell found it only twice during autopsy of 12,080 children. It is manifested by spiral rotation of the ureter around the kidney for more than one turn, as well as hydronephrosis. It is combined with stricture of the ureteral junction.

Hypoplasia of the ureter is usually combined with hypoplasia of the corresponding kidney or its half in case of duplication with multicystic dysplasia of the kidney. The ureter is a thin tube with a reduced diameter. It can be obliterated in some areas.

Ureteral stenosis is not uncommon. Most often, stenoses are localized in the ureteropelvic junction, the vesicoureteral segment (VUS), and less often at the level of the crossing with the iliac vessels. It is usually impossible to differentiate congenital and acquired strictures either clinically or histologically. Treatment is surgical, and in the case of preservation of renal function, it is aimed at restoring urodynamics. In case of terminal changes, nephrectomy is performed.

Ureteral valves are a duplication of the urothelial membrane. Sometimes valve-like folds consist of all layers of the ureter wall. They are usually localized in the peripelvic, pelvic and perivesical parts of the ureter. The anomaly is relatively rare, equally common in both sexes, both on the right and on the left. It manifests itself as a violation of the outflow of urine from the kidney with the development of ureterohydronephrosis. Treatment is usually surgical.

Ureteral diverticulum is a hollow formation that connects with the lumen of the ureter, almost always located in the lower third. It is rare. It can be multiple. The wall of the diverticulum only remotely contains the same elephants as the ureter. The diagnosis of ureteral diverticulum is based on excretory urogram data, which reveal a spherical or saccular shadow in the pelvic section of the ureter.

Ureterocele is a cystic dilation of the intravesical segment of the ureter. This is a developmental defect of the walls of the distal ureter in the form of an expansion of the intravesical section, protruding cystically into the cavity of the bladder and preventing the passage of urine. The wall of the ureterocele is covered with the mucous membrane of the bladder and consists of all layers of the ureter wall. From the inside, the cystic formation is lined with the mucous membrane of the ureter.

Ureteroceles are a common developmental defect (1.6% of all renal and UUT anomalies). They can be unilateral or bilateral. Ureteroceles of one of the duplicated ureters are very common. The causes of ureteroceles are underdevelopment of the neuromuscular apparatus of the distal ureter with a narrowed orifice. In pediatric urology, 80% of all ureteroceles are ectopic, while in adult practice, orthotopic ureteroceles are more common, since ectopic ureteroceles disrupt the outflow of urine from the kidney to a greater extent, leading to the death of the parenchyma. Therefore, the number of such patients in pediatric urology hospitals predominates.

Orthotopic ureterocele may not disturb urodynamics for quite a long time and, accordingly, do not require correction. Diagnostics of this defect today is not difficult. Most often, ureterocele is detected using ultrasound, if necessary, excretory urography, retrograde cystography to detect VUR, CT, MSCT, MRI and magnetic resonance urography can be used. Then, excretory urography with descending cystography is performed. On radiographs, a rounded increase in contrast in the bladder at the site of the ureter confluence is noticeable. With MSCT and MRI, a rounded cavity is also clearly defined. protruding into the lumen of the bladder.

There are two points of view on the problem of ureterocele treatment. The first is for open operations, the second is in favor of endoscopic dissection. Plastic surgeries can be as follows:

• one-stage ureterocystostomy with dissection of the ureterocele even with a practically non-functioning kidney or half of it;
• pyelo- or uretero-ureterostomy with preserved renal function with or without excision (dissection) of ureterocele;
• heminephrectomy with or without excision (dissection) of ureterocele.

This tactic is followed by most pediatric urologists. The main argument in favor of "open" operations is the high probability of VUR (30%) after endoscopic dissection of ureterocele, especially in its ectopic location. Supporters of endoscopic dissection, first proposed by I. Zielinski (1962), agree with the probability of VUR. In the case of VUR, they suggest reconstructive operations, the need for which arises in a third of patients. In this case, endoscopic dissection serves as the first stage of treatment, allowing to achieve some reduction in UUT dilation, facilitating subsequent plastic surgery. The absence of urodynamic disorders and clinical manifestations of obstruction in 52.38% of patients allows for dynamic observation without surgical correction.

Renal and UUT anomalies often turn out to be a predisposing factor for the development of ureterohydro- and hydronephrosis, kidney tumors, urolithiasis, and acute pyelonephritis. At the same time, there are significant difficulties in diagnosing and treating such patients, since some defects can be mistaken for a disease, and vice versa. All this can lead to diagnostic and therapeutic errors. In addition, most anomalies affect treatment tactics and complicate surgical interventions.

Today, due to the introduction of non-invasive and minimally invasive diagnostic methods, various endoscopy options, it has become possible not only to determine the type of defect based on indirect signs, but also to study in detail the pathological processes that have arisen, as well as to assess the condition of neighboring organs, their relationship with abnormally developed kidneys and uterine urinary tract. It is obvious that the concepts of kidney and uterine urinary tract anomalies are at a new stage of development. Modern treatment tactics differ from those generally accepted 5-10 years ago. The high incidence of kidney and uterine urinary tract anomalies and the complexity of open surgical interventions against their background created the need to introduce new minimally invasive treatment methods.

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