Hydronephrosis of the kidney - Overview of information

Hydronephrosis (from the Greek words hydor - "water" and nephros - "kidney") is a kidney disease characterized by expansion of the renal pelvis and calyces, progressive hypotrophy of the renal parenchyma with deterioration of all basic renal functions as a result of impaired urine outflow from the renal pelvis and calyces and hemocirculation in the renal parenchyma. Hydronephrosis accompanied by expansion of the ureter is called ureterohydronephrosis.

Synonym: hydronephrotic transformation.

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Epidemiology

Hydronephrosis is a relatively common disease. In childhood, hydronephrosis is more common in boys than in girls (ratio 5:2); more often on the left than on the right. Bilateral obstruction in children is observed in 15% of cases. In women aged 20 to 40, hydronephrosis occurs 1.5 times more often than in men, and in adults - in 1% of cases. In people over 40, hydronephrosis often serves as a symptom of other diseases, and the prognosis depends on the treatment of the underlying disease.

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Causes hydronephrosis

Hydronephrosis always develops as a result of obstruction of urine outflow, localized in any part of the urinary tract, but most often in the area of the ULJ. Often, a combination of causes causing obstruction of urine outflow is noted. All causes of hydronephrosis are divided into five groups:

1. obstructions located in the urethra and bladder;
2. obstructions along the ureter but outside its lumen;
3. obstructions caused by deviations in the position and course of the ureter;
4. obstructions existing in the lumen of the ureter itself or in the cavity of the renal pelvis;
5. changes in the walls of the ureter or renal pelvis that cause difficulty in the outflow of urine.

The causes of hydronephrosis of the first group are diseases that cause IVO, and if it exists for a long time, also a violation of the outflow of urine from the upper urinary tract:

• strictures, stones, tumors, diverticula, valves and foreign bodies of the urethra;
• sclerosis and prostate adenoma;
• tumors, stones, diverticula and foreign bodies of the bladder.

Even phimosis can be the cause of ureterohydronephrosis. Bilateral ureterohydronephrosis often develops when the obstruction is localized in the urethra and bladder. Ureteroceles, vesicoureteral reflux, and neurogenic bladder can also be conditionally included in this group (there is a combination of causes!). In children of the first year of life, the most common cause of hydronephrosis is the valves of the urethra.

The causes of hydronephrosis of the second group are diseases that cause external compression of the ureter at any level:

• chronic cystitis of various etiologies (including interstitial) with damage to the ureteral orifices;
• prostate adenoma with retrotrigonal growth (fish hook symptom);
• prostate cancer and tuberculosis with compression of the orifices;
• parapelvic cyst of the kidney;
• tumor processes in the pelvis and retroperitoneal tissue (sarcomas, lymphomas, intestinal tumors, etc.);
• enlarged lymph nodes (cancer metastases) and inflammatory processes in the retroperitoneal space (Ormond's disease, pelvic lipomatosis);
• bowel diseases (Crohn's disease, ulcerative colitis);
• consequences of gynecological, surgical, urological interventions and radiation therapy for neoplasms of the pelvic organs (cervix, rectum), etc.

The so-called accessory vessel (a vessel going to the lower segment of the kidney) crossing the ureter at the point where it exits the renal pelvis - in the LMS, is considered one of the most common causes of hydronephrosis. The significance of the accessory vessel is in the mechanical compression of the ureter (LMS) and in the effect on its neuromuscular apparatus.

As a result of the inflammatory reaction, perivascular and periureteral cicatricial adhesions are formed around the accessory vessel and the ureter, creating fixed kinks or compressing the ureteral junction, and in the ureteral wall itself, at the site of pressure, a cicatricial zone with a sharply narrowed lumen is formed - a strangulation groove. In case of ureteral strictures, their cause may be the so-called ovaricovaricocele. Changes caused by an accessory (crossed) vessel are a typical example of a combination of causes that obstruct the outflow of urine (groups 2 and 4 of hydronephrosis causes).

The causes of hydronephrosis of the third group are anomalies of the ureters, their kinks, curvatures, twists around the longitudinal axis, retrocaval location of the ureter. These causes usually lead to the development of unilateral ureterohydronephrosis.

The causes of hydronephrosis of the fourth group are stones, tumors and foreign bodies of the renal pelvis and ureter, valves and "spurs" on the mucous membrane in the area of the ureteral pelvis. Congenital and inflammatory strictures of the ureteral pelvis and ureter, cystic ureteritis, ureteral diverticula.

The causes of hydronephrosis of the last group are associated with functional disorders of the renal pelvis and ureter, unilateral or bilateral hypotension or atony of the ureter. This group also includes patients with neuromuscular dysplasia of the ureter, primary megaureter, as well as with the so-called "high" origin of the ureter from the pelvis, although in these diseases a combination of causes for the development of hydronephrosis is noted.

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Pathogenesis

According to modern teachings on hydronephrosis, its course is divided into three stages.

• Stage I - expansion of only the renal pelvis (pyelectasis) with minor impairment of renal function.
• Stage II - expansion of not only the renal pelvis, but also the calyces (hydronephrosis) with a decrease in the thickness of the renal parenchyma and a significant impairment of its function.
• Stage III - severe atrophy of the renal parenchyma, transformation of the kidney into a thin-walled sac.

Regardless of the cause (anatomical, functional, mixed) of obstruction development in hydronephrosis, urine outflow from the kidney is impaired, while typical pathophysiological processes begin to develop in the kidney and upper urinary tract, which allowed pathophysiologists to call this condition "obstructive uropathy". In hydronephrosis, the processes of urine secretion and reabsorption are preserved, but reabsorption lags behind secretion, which causes the accumulation of urine in the renal pelvis. This gives the right to consider the kidney a functioning organ in hydronephrosis of any stage. As shown by radioisotope studies, in case of obstruction at the level of the renal pelvis, sodium, iodine and colloidal gold isotopes are reabsorbed from the renal pelvis into the bloodstream.

At the initial stage of hydronephrotic transformation, with stasis of urine in the pelvis, hypertrophy of the musculature of the calyceal-pelvic system develops. Gradual hypertrophy of the spinal musculature of the calyces leads to a sharp increase in the pressure of urine on the papilla and fornical zone compared to the secretory pressure in the urinary tubules; this creates an obstacle to the normal excretion of urine. However, with such a relative balance, the kidney does not function for long. The working hypertrophy of the muscular elements of the minor calyces and pelvis is replaced by their thinning, which disrupts the outflow of urine from them and leads to dilation of the renal pelvis and calyces with subsequent atrophy of the papillae and renal parenchyma (stage II).

One of the important moments in the development of hydronephrosis is the delay in the introduction of urine from the functionally active areas of the kidney, which is observed even with a short-term increase in intrapelvic pressure, when the pelvis is not yet dilated. High pressure in the renal pelvis is caused not only by the urine entering it, but also by the contraction of the muscles of the calyces, especially the fornical and calyceal sphincters. Contraction of these hypertrophied sphincters contributes to the disruption of the integrity of the vaults of the calyces, which facilitates the reverse flow of urine from the pelvis into the renal parenchyma (renal pelvis reflux).

Already 24 hours after ureteral obstruction, hypotrophy and atrophy of the renal pyramids develop due to their compression by transfornical edema; the papillae gradually flatten. After 6-10 days, hypotrophy and atrophy of the pyramids reaches a significant degree; the papillae gradually become concave. By the end of the 2nd week, the fornices disappear, the walls of the calyx in the fornix area become more sloping and rounded. The Bertinian columns remain unchanged. The loops of Henle shorten or slowly disappear. Increasing fluid pressure in the renal pelvis leads to gradual obliteration of the pyramids, as well as compression of the Bertinian columns.

The damage to the renal glomeruli at this time is still insignificant. Some glomeruli function with high filtration pressure, others with low, so the glomerular filtrate secreted by the part of the parenchyma where glomerular filtration is still ensured by high blood pressure reaches the calyceal pelvis. From there, due to tubular reflux, the filtrate enters the collecting ducts of that part of the parenchyma where the glomeruli are still functioning, but with reduced blood pressure. The large difference in blood pressure between these two groups of glomeruli promotes reverse filtration of urine into the low-pressure glomeruli.

Due to the disappearance of the fornices, the lumen of the collecting ducts expands, facilitating the flow of urine from the renal pelvis into the tubular system. The flow of urine does not stop, and pyelovenous reflux and lymphatic reabsorption are replaced by glomerular reverse filtration. Due to extensive atrophy of the tubular apparatus, the urine circulating in the kidney is identical to the glomerular filtrate. Additional intermittent increases in intra-abdominal pressure gradually lead to a disorder of circulation in the renal glomeruli and their destruction (usually by the 6th-8th week from the onset of obstruction). Subsequently, with complete obstruction, multiple ruptures of the cupial vaults occur, as a result of which urine freely enters the renal interstitial spaces, the circulatory and lymphatic systems.

Increased intraparenchymatous pressure disrupts blood flow in the renal medulla, leading to pyramidal atrophy. Due to prolonged transfornical edema, renal parenchyma atrophy is especially noticeable in the pyramids, while it is less pronounced in the cortex and Bertiny columns. Impaired blood circulation in the cortical and medullary capillaries leads to general impaired blood circulation in the parenchyma, hypoxia, and impaired tissue metabolism, contributing to total atrophy of the renal cortex.

Thus, the development of hydronephrosis is characterized by two phases: in the first, the medulla atrophies, in the second, the cortex.

The vascular apparatus of the kidney undergoes significant changes in the conditions of hydronephrotic transformation. Both cortical and interlobar vessels become thinner and longer in hydronephrotic restructuring. At the same time, there is a violation of the elastic membrane of the intrarenal vessels, as well as proliferation of the endothelium.

Urine production and its entry into the renal pelvis, as well as some reabsorption of the glomerular filtrate, occur even in advanced hydronephrotic transformation: after the disappearance of the fornices, the reabsorption of the glomerular filtrate occurs by tubulovenous reflux. Consequently, renal pelvis-renal refluxes play an important role in the pathogenesis of hydronephrotic transformation of the organ.

These compensatory mechanisms lead to a decrease in pressure in the renal pelvis and calyces, thereby promoting the preservation of renal secretion.

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Symptoms hydronephrosis

Symptoms of hydronephrosis are often absent and are detected only in the case of infection, kidney injury, or accidentally detected during palpation of the abdominal cavity as a fluctuating tumor. Clinicians do not distinguish symptoms of hydronephrosis separately. The most common pain is in the kidney area, of varying intensity or constant aching nature, and in the early stages the pain is of the nature of attacks of renal colic. Patients often note a decrease in the amount of urine before attacks, as well as during them, and an increase in the amount of urine after the attack subsides.

In advanced hydronephrosis, acute pain disappears. Body temperature during attacks of pain in hydronephrosis may increase in the case of urinary infection and pyelonephritis, as a result of pyelovenous reflux. One of the symptoms of hydronephrosis is a tumor-like formation palpated in the hypochondrium, and in case of large hydronephrosis - extending beyond it. Hematuria is a common, sometimes the only symptom of hydronephrosis. It occurs due to a sudden and rapid decrease in intrapelvic pressure during short-term restoration of urine outflow from the kidney. The source of bleeding are the veins of the fornix.

Aseptic unilateral hydronephrosis can proceed latently, patients consider themselves healthy for a long time, despite the progressive process. Even with advanced unilateral hydronephrosis, symptoms of renal failure are usually not observed, since the opposite kidney compensates for the function of the affected one.

Bilateral hydronephrosis gradually leads to the progression of chronic renal failure and death from uremia. Among the complications of hydronephrosis are acute or chronic pyelonephritis, the formation of secondary stones and ruptures of the hydronephrotic sac during trauma; with bilateral hydronephrosis, chronic renal failure and nephrogenic arterial hypertension are characteristic.

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Forms

Based on modern theoretical concepts of hydronephrosis, the disease is divided into two forms.

• Primary, or congenital, hydronephrosis, which develops as a result of some anomaly of the upper urinary tract.
• Secondary, or acquired, hydronephrosis as a complication of any disease (for example, urolithiasis, tumors of the kidney, pelvis or ureter, damage to the urinary tract).

Hydronephrosis can be unilateral or bilateral. Both congenital and acquired hydronephrosis can be aseptic or infected.

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Diagnostics hydronephrosis

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Clinical diagnosis of hydronephrosis

Hydronephrosis is often asymptomatic. The most common symptoms of hydronephrosis are:

• pain in the lumbar region;
• a palpable formation in the hypochondrium, and if large, in the corresponding half of the abdomen;
• hematuria;
• hyperthermia;
• dysuria.

The anamnesis collection includes:

• the presence of the above symptoms and the time of their appearance from the moment of examination
• previous operations and other diseases of the pelvic organs, abdominal cavity and retroperitoneal organs.

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Physical examination includes:

• palpation - detection of a formation in the hypochondrium;
• percussion - tympanic sound if the formation is located retroperitoneally, dull sound if the kidney is large and the abdominal organs are displaced;
• rectal or vaginal examination - assessment of the condition of the prostate and external genitalia.

Laboratory diagnostics of hydronephrosis

In a general blood test, attention is paid to the leukocyte content, white blood cell count, and ESR. Leukocytosis with a shift in the formula to the left and an increase in ESR indicate the addition of an infection. In case of bilateral hydronephrosis, a decreased hemoglobin content may indicate renal failure.

General urine analysis reveals leukocyturia, tubular proteinuria, hematuria, and, in the case of bilateral lesions, a decrease in the relative density of urine. In the presence of nephrostomy drainage, urine analysis from the drainage allows indirect assessment of kidney function.

Urine analysis according to Nechiporenko allows us to judge the activity of the inflammatory process.

Bacteriological analysis of urine with determination of sensitivity of microflora to antibacterial drugs allows to identify the causative agent of infection of the upper urinary tract and prescribe adequate antibacterial therapy. Leukocyturia with multiple negative bacteriological tests of urine for non-specific microflora serves as an indication for specific studies to exclude tuberculosis of the genitourinary system.

In a biochemical blood test, it is necessary to determine the content of creatinine and urea, as well as electrolytes: potassium and sodium. An increase in the concentration of creatinine and urea is often observed in bilateral hydronephrosis.

If secondary hydronephrosis is suspected, laboratory diagnostics include tests necessary to diagnose the underlying disease [blood test for prostate-specific antigen (PSA), urine cytology].

Instrumental diagnostics of hydronephrosis

Ultrasound is used as a screening test; it allows one to assess the degree of expansion of the renal pelvis and calyces, the ureter, the presence of stones, and the condition of the contralateral kidney.

Doppler sonography allows us to assess the blood supply to the kidney and identify the presence or absence of an additional or crossed vessel.

Survey urography allows to identify stones, the cause or complication of hydronephrosis.

Excretory urography is used to evaluate the anatomy and function of the kidneys and upper urinary tract, determine the location of the upper urinary tract obstruction, and establish its extent. When performing excretory urography, the condition of the contralateral kidney is assessed on early images (7th and 10th minutes) and the calyceal-pelvic system and ureter are visualized. The condition of the affected kidney and upper urinary tract on the ipsilateral side is assessed on delayed images (an hour or more). Excretory urography is completed when the ureter is contrasted below the level of obstruction; thus, the extent of the obstruction can be determined.

Micturition cystourethrography is a method for detecting vesicoureteral reflux, which in 14% of cases is combined with ureteral stricture or megaureter.

Spiral CT with bolus contrast enhancement is indicated for:

• insufficient information content of excretory urography;
• suspected tumors of the abdominal organs, retroperitoneal space, kidneys and upper urinary tract.

Unlike excretory urography, spiral CT allows one to assess not only the location and extent of the stricture, but also the condition of the surrounding tissues (vessel, degree of periureteral fibrosis).

Dynamic nephroscintigraphy and radioisotope renography provide mainly information on the function of the kidneys and upper urinary tract. This study is necessary to judge the degree of dysfunction of the affected kidney, the nature of the elimination of the radiopharmaceutical from the upper urinary tract, and the condition of the contralateral kidney.

If a diagnosis of hydronephrosis is established, special research methods are used according to indications.

• Antegrade pyeloureterography in the presence of nephrostomy drainage allows visualization of the upper urinary tract and determination of the location and extent of obstruction.
• Retrograde ureteropyelography is used before surgery; the method allows to determine the extent of obstruction. Indication for retrograde ureteropyelography is the lack of visualization of the ureter below the level of obstruction when performing other examination methods (excretory urography, antegrade pyeloureterography, CT).
• Diapeutic ureteropyeloscopy is an invasive endoscopic intervention used in the absence of clear data on the condition of the ureter after using non-invasive research methods or as the first stage in performing endoscopic surgery to correct stricture of the upper urinary tract.
• Endoluminal ultrasonography is an expensive method of examination, requiring training in the use and interpretation of the information obtained. The advantage of the method is the ability to assess in detail the condition of the ureter wall and surrounding tissues.
• Perfusion pyelomanometry (Whitaker test) is used for differential diagnostics between obstructive and non-obstructive dilation of the renal pelvis and ureter. This examination method requires nephrostomy drainage, special urodynamic equipment and an electron-optical converter. Fluid flows into the pelvis through the drainage at a rate of 10 ml/min. The pressure in the pelvis and bladder is measured, a difference of less than 15 mm Hg is considered normal, with a difference of more than 22 mm Hg the fact of the presence of obstruction is considered confirmed. With a pressure difference of more than 15 mm Hg but less than 22 mm Hg the perfusion rate increases to 15 ml/min; a difference of more than 18 mm Hg is considered a sign of obstruction.

To clarify the diagnosis, it is possible to perform ultrasound, excretory urography and dynamic nephroscintigraphy with a diuretic, which allows increasing the diagnostic value of these research methods. The algorithm for diagnosing hydronephrosis is presented in Fig. 19-1.

Differential diagnosis

Differential diagnostics of hydronephrosis is carried out between hydronephrosis and various diseases of the kidneys and abdominal organs, depending on which symptom of hydronephrosis predominates in the clinical picture.

In case of pain, hydronephrosis should be differentiated from nephrolithiasis and nephroptosis. Survey urography or CT in case of X-ray negative stones confirms or excludes nephrolithiasis. In case of nephroptosis, unlike hydronephrosis, pain occurs during movement and physical exertion and quickly subsides at rest. Comparison of excretory urograms in the lying and standing positions allows establishing the diagnosis. A combination of nephroptosis and stricture of the ureteral ureteral junction is often encountered.

When a formation is palpated in the retroperitoneal space, hydronephrosis is differentiated from a tumor, polycystic disease and solitary cyst of the kidney.

In case of a tumor, the kidney is slightly mobile, dense, lumpy, and the pyelogram shows deformation of the renal pelvis with compression or "amputation" of the calyces. In case of polycystic kidney disease, both kidneys are enlarged and lumpy; symptoms of renal failure are observed. A typical pyelogram: an elongated renal pelvis and branched calyces, elongated in the form of crescents. In case of a solitary renal cyst, a typical cystogram reveals compression of the calyceal-pelvic system in accordance with the location of the cyst.

Performing a CT scan allows you to clarify the diagnosis.

In case of hematuria and pyuria, hydronephrosis must be differentiated from a tumor of the renal pelvis, pyonephrosis and tuberculosis (mainly by radiological methods).

When pyelocalyectasis is detected, differential diagnosis should be carried out with the following conditions and diseases:

• diabetes insipidus;
• taking diuretics;
• physiological polydipsia and polyuria;
• "calyceal" diverticula:
• polymegacalicosis;
• extrarenal pelvis;
• Prune-Belli syndrome;
• parapelvic cyst;
• papillary necrosis;
• pregnancy.

In most of these diseases and conditions, radioisotope examination does not reveal any impairment of kidney function.

When ureteropyelocalyectasia is detected, differential diagnostics should be performed between vesicoureteral reflux (micturition urethrocystography), ureterocele, megaureter, ureteral position anomalies (retrocaval ureter, retroiliac ureter). The diagnosis of "hydronephrosis" is established by excretory urography, antegrade and retrograde ureteropyelography, and spiral CT.

Treatment hydronephrosis

Treatment of hydronephrosis has certain goals:

• Elimination of the cause that led to the development of hydronephrosis.
• Preservation of the kidney.
• Reduction of the size of the renal pelvis (if necessary).

Indications for hospitalization

The patient is hospitalized if there is a need for planned surgical treatment of hydronephrosis. Emergency hospitalization is indicated for the elimination of complications of hydronephrosis, such as:

• renal colic (to relieve pain and clarify the diagnosis);
• attack of pyelonephritis (kidney drainage, antibacterial therapy);
• spontaneous rupture of hydronephrosis (nephrectomy);
• exacerbation of chronic renal failure (hemodialysis).

Non-drug treatment of hydronephrosis

Dynamic observation is used in the absence of clinical manifestations of the disease and normal function of the ipsilateral kidney. If the kidney functions normally in children, in order to avoid an error in choosing treatment (in case of functional hydronephrosis, a variant of development of the renal pelvis), dynamic observation is used for 6-12 months with subsequent repeated comprehensive examination of the child.

Conservative treatment of hydronephrosis is not of primary importance and plays a supporting role in preparing the patient for surgical treatment, as well as in eliminating complications of hydronephrosis.

Surgical treatment of hydronephrosis

Surgical treatment of hydronephrosis has the following goals:

• restoration of normal passage of urine from the kidney;
• preservation of kidney function;
• prevention of progression of chronic pyelonephritis and death of renal parenchyma.

X-ray endoscopic and open plastic surgery is indicated at the stage of unilateral and bilateral hydronephrosis, when the function of the parenchyma is sufficiently preserved, and the cause of the disease can be eliminated.

Indications for surgical treatment of hydronephrosis:

• frequent exacerbations of chronic pyelonephritis;
• formation of "secondary" stones;
• decreased kidney function;
• pain leading to social maladjustment of the patient;
• chronic renal failure.

Performing percutaneous puncture nephrostomy or installing an internal stent in the preoperative period is indicated in the following situations:

• exacerbation of chronic pyelonephritis;
• progression of chronic renal failure in a bilateral process or in hydronephrosis of a single anatomical or functioning kidney;
• pain relief in patients with severe concomitant diseases;
• terminal stages of hydronephrosis, when it is necessary to decide between nephrectomy and organ-preserving surgery.

To restore the patency of the LMS, the following types of operations are used for hydronephrosis:

• "open" reconstructive plastic interventions:
  • various variants of ureteropyeloanastomosis with or without resection of the narrowed area;
  • "patchwork" plastic surgeries;
  • ureterocalicoanastomosis;
• endourological (X-ray endoscopic) interventions using percutaneous and transurethral approaches;
  • bougienage;
  • balloon dilation;
  • endotomy (endopyelotomy, endoureterotomy);
  • use of the "Acucise" balloon catheter;
• laparoscopic and retroperitoneoscopic plastic interventions using transabdominal and retroperitoneal approaches.

The method of choice in the treatment of hydronephrosis is reconstructive plastic surgery aimed at restoring the anatomical and functional integrity of the urinary tract and preserving the organ. The effectiveness of open reconstructive plastic surgery for hydronephrosis is 95-100%.

Advantages of open surgical treatment of hydronephrosis:

• high success rate;
• extensive experience of use;
• the possibility of performing resection of the renal pelvis during surgery, monitoring the presence of vessels in the paraurethral region;
• familiarity of most urologists with the technique of these operations.

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The disadvantages include:

• large volume of operation;
• the presence of a large incision (pain, injury to the muscles of the anterior abdominal wall, cosmetic defect);
• long hospitalization periods, low cost-effectiveness;
• use of organ-removing operations in case of failure (in 5-10% of cases).

For hydronephrosis caused by stricture of the ureteral junction, the following open reconstructive plastic surgeries are best known.

The operation for Fenger's hydronephrosis, based on the Heineke-Mikulich pyloroplasty technique, involves longitudinal dissection of the posterior wall of the ureter in the stricture area and suturing its walls in the transverse direction. However, even the use of atraumatic sutures does not exclude subsequent deformation of the newly formed ureteral junction. This method was used only in cases of hydronephrosis with a "low" ureteral outlet.

In case of "high" ureteral origin, Foley's V-shaped ureteroplasty was widely used for many years. The operation in several modifications is sometimes used today, especially with laparoscopic and retroperitoneoscopic access. The method involves creating a wide funnel-shaped expansion of the ureteral pelvis. The upper third of the ureter and the posterior surface of the expanded pelvis are mobilized. A triangular flap is formed with its apex facing the ureter using a Y-shaped incision that passes from the ureter through the stricture to the lower wall of the pelvis. Then the apex of the angle of the pelvic flap is sutured to the lower angle of the ureteral incision. The lateral edges of the incisions of the newly formed funnel are sutured with a nodal or continuous suture without suturing the mucous membrane using an atraumatic needle. A common complication of this method of plastic surgery is necrosis of the flap apex. recognition

Among the various variants of "flap" plastic surgery of the ureteral pelvis, the Calp-De Virda operation in the modification of Scardino-Prince has received wide recognition. To perform it, careful mobilization of the anterior and posterior surfaces of the renal pelvis and ureter is required. The incision on the posterior surface of the ureter begins from healthy tissues, continues through the stricture to the posterior wall of the pelvis and further along its medial, superior and lateral edge to the lower-lateral angle, cutting out from the posterior wall of the pelvis a semilunar flap 1-2 cm wide with a base at the lower edge of the pelvis. The flap is folded down, its edges are sutured with the edges of the ureter, due to which a new ureteral pelvis with a wide lumen is formed. This operation can be used both for "high" and "low" ureteral origin.

All of the above operations for hydronephrosis, despite their certain effectiveness, are currently performed relatively rarely, since they all have a significant number of limitations and disadvantages, the main one of which is considered to be the lack of resection of the narrowed area.

In hydronephrosis caused by stricture of the ureteral ureteral junction, the Anderson-Hines operation is effective, which consists of resection of the narrowed area, with the imposition of an end-to-end anastomosis between the ureter and the pelvis; in the presence of a large pelvis, resection of the pelvis can also be performed. This operation has become widespread.

Often the cause of hydronephrotic transformation is an additional vascular bundle to the lower segment of the kidney. The operation of choice in such a situation is resection of the narrowed section of the LMS with the implementation of an amtevasal pyelo-pyelo- or pyelo-ureteral anastomosis. This changes the relationship between the vessel and the LMS zone, as a result of which the vessel is behind the anastomosis and does not compress it.

The greatest difficulties are associated with the treatment of hydronephrosis with an intrarenal pelvis and an extended stricture of the ureteral junction and the upper third of the ureter. In such situations, uretero-calico-anastomosis can be used - the Neuwirth operation. The ureter, cut off within the healthy tissues, is sutured into the lower calyx, fixing it to the calyx with internal sutures and to the renal capsule with external sutures. Disadvantages of the method: difficulty in fixing the ureter inside the calyx and possible formation of a valve-like structure at the anastomosis site. Cases of scarring of the lower segment of the kidney with restenosis of the ureter have been described. In this regard, the operation is supplemented with a planar or wedge-shaped resection of the parenchyma of the lower segment of the kidney with careful isolation of the calyx for anastomosis with the ureter, or an operation developed by N.A. In 1979, Lopatkin developed a latero-lateral uretero-pyelo-calico-anastomosis.

Surgery for hydronephrosis involves careful mobilization of the kidney, its vascular pedicle, and ureter. Next, the medial half of the lower segment of the renal parenchyma is resected to its gates, widely opening the lower calyx, its neck, and the renal pelvis, and avoiding damage to the main vessels. The ureter is dissected longitudinally to a length corresponding to the length of the opened pelvis, neck, and calyx. The next step is to suture the edges of the dissected ureter to the corresponding edges of the dissected pelvis, neck, and calyx on an intubating drainage with a continuous suture on an atraumatic needle, capturing the edge of the renal parenchyma. Such an operation, by forming an artificial pelvis, creates favorable conditions for maintaining urodynamics close to physiological and the passage of urine from the kidney, in contrast to the Neuwirth operation, after which the evacuation of urine is carried out with increased hydrostatic pressure in the pelvis.

Ureterolysis - the separation of the ureter and ureteral junction from adhesions, is currently almost never used as an independent operation to treat hydronephrosis, since the removal of an external obstruction does not always eliminate the consequences of its pressure on the ureter wall. Due to prolonged compression by a cicatricial cord or an additional vessel, sclerotic processes develop in the thickness of the ureter wall, causing a narrowing of its lumen. In such situations, it is necessary to combine ureterolysis with resection of the narrowed area, especially if after dissection of the adhesion or cord on the ureter wall, a "sgrangulation groove" is clearly visible. During ureterolysis, no matter for what purpose it is performed, one should be guided by a strict rule - be careful to avoid damage to the organs surrounding the ureter, treat scar tissue carefully and do not damage the tissue of the ureter itself. It is necessary to work "in a layer", trying to use tissue dissection "in a sharp way" as much as possible, rather than their stratification. Preliminary hydropreparation is advisable where possible. Gentle manipulations are a preventive measure against recurrence of the cicatricial process.

In most cases, after reconstructive plastic surgery for hydronephrosis, drainage of the renal pelvis and splinting of the ureteral junction area are performed. The splinting tube is removed 2-3 weeks after surgery. Nephrostomy drainage is removed from the renal pelvis only when free urine flow down the ureter is restored (usually after 3-4 weeks). Restoration of urine flow is determined using antegrade pyeloureterography.

Laparoscopic and retroperitoneoscopic operations, which have similar effectiveness, are free from the disadvantages of "open" operations. The main factors limiting the prevalence of these operations are:

• high cost of consumables;
• technical complexity of anastomosis;
• increased risk of anesthetic complications during long-term surgery.

Contraindications to performing this type of surgery for hydronephrosis:

• history of surgical interventions on abdominal organs;
• repeated reconstructive plastic surgeries on the upper urinary tract.

The operation for hydronephrosis begins with performing pneumoperitoneum or retropneumoperitoneum. Using several trocars inserted into the abdominal cavity or retroperitoneally (4-5 trocars, one of which is used to insert an endoscope connected to a video camera, and the others - various manipulators), the kidney, renal pelvis and ureter are isolated by blunt and sharp means, the narrowed area (pelvis) is resected and an anastomosis is applied. To perform such interventions, special equipment is required, as well as a highly qualified urologist with the skills to perform both open and endoscopic interventions.

With the development of X-ray endoscopic technology, endourological minimally invasive methods of treating hydronephrosis have emerged and begun to develop: bougienage, balloon dilation and endotomy (endoscopic dissection) of strictures of the ureteral lining of the ureter using antegrade (percutaneous) and retrograde (transurethral) approaches.

Stricture dilation consists of its expansion by successive replacement of dilatations of increasing caliber along a guide wire under X-ray television control. Balloon dilation is technically performed in the same way as balloon dilation of vessels: the radiopaque markers of the balloon are installed under X-ray television control so that the stricture is located between them: the balloon is filled with a diluted contrast agent, and as the "waist" on the balloon is eliminated, they decide on the expansion of the narrowing. Endotomy (endopyelotomy, endoureterotomy) is performed "by eye" through a special endoscope inserted into the renal pelvis or ureter; by longitudinal or oblique dissection of the stricture with a cold knife or electrode through all layers of the narrowing to the paranephric tissue. All methods of X-ray endoscopic treatment of strictures of the ureteral ligament and ureter involve splinting (intubation) of the stricture for a period of 4-6 weeks (for example, an internal or external stent, an intubating nephrostomy). A special "cutting" balloon catheter ("Accuсise") has been developed, combining the principles of balloon dilation and endotomy.

In hydronephrosis caused by stricture of the ureteral ureteral junction, the effectiveness of X-ray endoscopic interventions performed through percutaneous and transurethral access is 75-95% for primary interventions and 65-90% for repeated operations. Endopyelotomy through percutaneous and transurethral access followed by splinting of the stricture zone for 4-6 weeks is the most pathogenetically substantiated method of X-ray endoscopic interventions. Favorable prognostic criteria for the effectiveness of X-ray endoscopic intervention:

• no indication of surgical intervention in the anamnesis (“primary” stricture);
• early stages (up to 3 months) of performing surgery in the case of the formation of a “secondary” stricture of the upper urinary tract;
• the length of the stricture is less than 1 cm;
• dilation of the renal pelvis up to 3 cm; o minor (up to 25%) or moderate (26-50%) deficiency of secretion of the ipsilateral kidney;
• lack of data indicating renal pelvis-vasal conflict, significant paraureteral fibrosis in the narrowing zone.

In case of complete loss of the ipsilateral kidney, nephrectomy (in case of ureteral strictures) or nephroureterectomy with removal of the ureter below the narrowing zone (in case of ureteral strictures) is performed. In case of kidney loss as a result of vesicoureteral reflux or megaureter, nephroureterectomy with endoscopic resection of the bladder is performed.

Further management

After 3-4 weeks after open and 4-6 weeks after any endoscopic surgery for hydronephrosis, the intubating drainage (internal stent) is removed; ultrasound (with dilation of the renal pelvis) and excretory urography are performed.

Radioisotope examination is performed once a year. Control laboratory examination (general blood test, general urine test) is performed one month after the operation, before removal of the internal stent and then every 3 months during the first year after the operation.

One year after surgery for hydronephrosis and in the absence of complaints, the patient's renal function should be monitored once a year and an ultrasound of the kidneys should be performed once every 6 months.

Information for the patient

A patient diagnosed with hydronephrosis should be informed about:

• the need to conduct a comprehensive clinical and laboratory examination aimed at identifying the causes of the development of hydronephrosis and the degree of decline in kidney function;
• whether the treatment of hydronephrosis is effective;
• the need to eliminate the causes that disrupt the outflow of urine from the kidney;
• the possibility of developing renal failure with bilateral hydronephrosis.

Prevention

Fetal ultrasound at 16 weeks of gestation is an effective method for screening congenital hydronephrosis.

Prevention of the primary form of the disease has not been developed. Secondary hydronephrosis can be prevented if prevention of diseases leading to its development is carried out in a timely manner.

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Forecast

The prognosis for recovery in hydronephrosis is determined by the preserved passage of urine through the upper urinary tract and the degree of decline in the function of the ipsilateral kidney. The prognosis for life in unilateral hydronephrosis is relatively favorable. In bilateral hydronephrosis, the prognosis is very serious due to the development of chronic renal failure due to the progression of parenchymal atrophy of both kidneys, pyelonephritic and nephrosclerotic processes.

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