Urolithiasis

Urolithiasis (nephrolithiasis, urolithiasis) is the second most common kidney disease, occurring at any age, characterized by the deposition of stones in the renal pelvis and urinary tract. The incidence of nephrolithiasis in industrialized countries is growing in parallel with the spread of obesity and currently amounts to 1-2%.

Epidemiology

The risk of developing urolithiasis is 5-10%, the incidence of men is 3 times higher than women. Urolithiasis most often occurs in patients aged 40-50 years.

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Causes urolithiasis

Recently, due to changes in diet, a sedentary lifestyle, and exposure to various unfavorable environmental factors, urolithiasis is becoming more common.

Urolithiasis develops as a result of excessive consumption of animal proteins and salt, deficiency of potassium and calcium, obesity, alcoholism, genetic and environmental factors.

Secretion of urates and calcium is impaired in lead and cadmium intoxication. Hypercalciuria with an autosomal dominant type of inheritance is found in 40-50% of patients with frequently recurring calcium nephrolithiasis.

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Risk factors

For patients with any form of urolithiasis, it is necessary to analyze the causes of stone formation in order to subsequently prescribe treatment or remove the stone. It should be noted that none of the types of surgical intervention, in fact, is a method of treating urolithiasis, but only rids the patient of the stone.

Factors that increase the risk of stone formation

Factor	Examples
Family history of urolithiasis
Living in endemic regions
Monotonous food rich in substances that promote stone formation
Lack of vitamin A and B vitamins in food
Medicines	Calcium preparations; Vitamin D preparations; Ascorbic acid (more than 4 g per day); Sulfonamides
Urinary system abnormalities	Tubular ectasia; stricture (narrowing) of the ureteral junction; calyceal diverticulum; calyceal cyst; ureteral stricture; vesicoureteral reflux; ureterocele; horseshoe kidney
Diseases of other systems	Hyperparathyroidism; Renal tubular acidosis (total/partial); Jejuno-ileacal anastomosis; Crohn's disease; Condition after resection of the ileum; Malabsorption syndrome; Sarcoidosis; Hyperthyroidism

Thus, among the factors influencing the formation of calcium oxalate stones, diseases of the endocrine system (parathyroid glands), gastrointestinal tract and kidneys (tubulopathy) are often distinguished. Violation of purine metabolism leads to the development of urate nephrolithiasis.

Chronic inflammatory diseases of the genitourinary system can contribute to the formation of phosphate (struvite) stones.

Thus, depending on the etiological factors and developing metabolic disorders, urinary stones with different chemical compositions are formed.

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Pathogenesis

There are several theories of stone formation.

• According to the matrix theory, the formation of the core of a forming stone is caused by desquamation of the epithelium as a result of the development of an infectious disease of the urinary system.
• The colloid theory is based on the transition of protective colloids from a lipophilic form to a lipophobic one, which creates favorable conditions for pathological crystallization.
• The ionic theory explains the formation of stones by the insufficiency of urine proteolysis under conditions of altered pH values.
• The precipitation and crystallization theory considers the formation of a stone in supersaturated urine during an intensive crystallization process.
• The inhibitory theory explains the formation of stones by an imbalance of inhibitors and promoters that maintain urine metastability.

All theories of stone formation are united by the main condition - a violation of urine metastability and supersaturation of urine with stone-forming substances.

Reduced calcium absorption in the renal tubules and excess in the gastrointestinal tract together with accelerated bone resorption are caused by a genetically predetermined increase in the number of cellular receptors to calcitriol. A genetically inherited urate-calcium lithiasis with hypertension developing at a young age has been described, which is based on a tubular defect in calcium excretion and Na reabsorption. Genetic disorders cause the most severe forms of nephrolithiasis in oxalosis, cystinosis, Lesch-Nyhan syndrome, and glycogenosis type I.

The pathogenesis of urolithiasis is associated with impaired renal acidogenesis, combined with increased renal excretion or excessive absorption of calculus-forming metabolites in the gastrointestinal tract. Excessive consumption of animal protein leads not only to hyperuricosuria, but also to increased synthesis of oxalic acid (hyperoxaluria) and hypercalciuria.

Excessive sodium chloride intake or dietary potassium deficiency also leads to hypercalciuria (due to increased calcium absorption in the gastrointestinal tract and intake from bone tissue), hyperoxaluria and decreased excretion of citrates - inhibitors of stone growth, and also increases osteoporosis. Alcohol induces hyperuricemia (intracellular breakdown of ATP, decreased tubular secretion of urates) and hypercalciuria.

In addition to hyperexcretion of the indicated stone-forming salts, persistent shift in urine pH, dehydration and oliguria, and urodynamic disorders (vesicoureteral reflux, pregnancy, intestinal atony) play an important role in the pathogenesis of nephrolithiasis.

To understand the process of stone formation and select the optimal treatment regimen, a unified classification has been created based on the chemical composition of urinary stones, the clinical form of the disease and various factors contributing to stone formation, identified in the patient's medical history.

The process of urinary stone formation can be long, often without clinical manifestations; it can manifest itself as acute renal colic caused by the passage of microcrystals.

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Classification of urinary stones

• Inorganic urinary stones:
  • calcium oxalate (wedelite, wevelite); calcium phosphate (whitlockite, brushite, apatite, carbonate apatite, hydroxyapatite), calcium carbonate. Calcium urinary stones are found in 75-85% of cases of urolithiasis; more often in men over 20 years old; relapse is noted in 30-40% of cases, with brushite stones - in 65%). Magnesium-containing urinary stones occur in 5-10% of cases (newberite, magnesium ammonium phosphate monohydrate, struvite), which are detected in 45-65% of cases, more often in women with infectious diseases of the genitourinary system (wevelite, wedelite, brushite). With struvites, there is a high risk of developing inflammatory complications. Relapses occur in 70% of cases with incomplete removal of the urinary stone or in the absence of treatment of urinary infection.
• Urinary stones of organic origin:
  • With a constantly low urine pH (5.0-6.0), urinary stones are formed from uric acid and its salts (ammonium urate, sodium urate, uric acid dihydrate), and their frequency increases with age. Urate urinary stones (5-10% of cases of urolithiasis) are more often formed in men. Metaphylaxis reduces the risk of relapse completely.
  • At urine pH less than 6.5, the rarest protein urinary stones (cystine, xanthine, etc.) are formed, accounting for 0.4-0.6% of cases of urolithiasis and associated with congenital disorders of the metabolism of the corresponding amino acids in the body of patients. Relapses reach 80-90%. Prevention is extremely difficult and often ineffective.

However, pure stones occur in approximately 50% of cases, and in the rest, mixed (polymineral) urinary stones of various compositions are formed in the urine, characterized by various metabolic processes occurring in parallel, and often by infectious processes.

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Symptoms urolithiasis

Symptoms of urolithiasis are characterized by pain syndrome of varying intensity, chronic course, frequent addition of pyelonephritis, and outcome in chronic renal failure with bilateral lesions.

• Pelvic nephrolithiasis. Caused by the deposition of small stones in the renal pelvis. A recurrent course is observed with repeated attacks of excruciating pain caused by acute obstruction of the urinary tract by a stone - renal colic with hematuria.
• Calyceal-pelvic (staghorn) nephrolithiasis. The most severe, rarer form of nephrolithiasis, caused by a calculus occupying the entire pelvic-caliceal system. With staghorn nephrolithiasis, renal colic does not develop. Periodically, low-intensity pain in the lower back, pain in the right side bother, macrohematuria is episodically detected, secondary pyelonephritis is especially common, chronic renal failure slowly progresses.
• Acute complications. Include secondary (obstructive) pyelonephritis (see "Pyelonephritis"), postrenal acute renal failure, fornical bleeding.
• Chronic complications. Unilateral nephrolithiasis leads to atrophy of the renal parenchyma due to its hydronephrotic transformation, as well as to the formation of pyonephrosis, renovascular hypertension. The outcome of bilateral nephrolithiasis is often renal shrinkage with the development of terminal chronic renal failure.

Although rare, urolithiasis symptoms may be absent for a certain period of time, and the stone may be detected by chance during X-ray or ultrasound examination. This so-called latent form of the chronic phase of urolithiasis does not depend on the size of the stone, but is determined mainly by its location, mobility, and the presence or absence of infection. For example, a large stone localized in the renal parenchyma, without disruption of intrarenal urodynamics and the absence of secondary infection, may exist for a long time without causing symptoms of urolithiasis.

However, often the only complaint in a significant number of patients with such stones is a dull pain in the lower back, which is explained by the involvement of the fibrous capsule of the kidney in the inflammatory process. At the same time, a small but mobile stone in the pelvis, disrupting the outflow of urine from the kidney, most often gives a severe clinical picture with significant changes in the enatomical and functional state of the kidney.

Renal colic is the main symptom of urolithiasis

Severe forms of the disease have characteristic symptoms of urolithiasis. The most common symptom in these cases is pain, often manifested as an attack of renal colic. It is characterized by sudden acute pain in the lower back on the affected side, with typical irradiation along the anterior abdominal wall down the ureter to the bladder and genitals. Sometimes the pain can cover the entire abdominal area or be most pronounced in the area of the contralateral healthy kidney. Patients with renal colic are in a state of motor agitation, constantly changing their position.

Then, symptoms such as dysuria, nausea, vomiting, flatulence, abdominal wall tension, simulating the picture of acute abdomen, may appear. These signs may also be accompanied by chills, an increase in temperature to subfebrile numbers, a slow soft pulse, rapid breathing, dry mouth. Usually, an attack of renal colic lasts for several hours, but may not pass for several days. The cessation of pain may occur either suddenly or with a gradual regression of symptoms. The cessation of pain is explained either by a change in the position of the stone, or its passage from the ureter and the restoration of urine flow from the kidney.

The cause of renal colic is mechanical obstruction of the ureter, accompanied by spasm of its wall and increased intra-pelvic pressure, which in turn causes acute stretching of the renal pelvis and congestion in the kidney, causing stretching of the fibrous capsule and irritation of the rich network of nerve endings.

Symptoms of urolithiasis, simulating diseases of the abdominal organs (acute abdomen) ( flatulence, tension of the abdominal wall, nausea, vomiting, etc.) in renal colic, are a consequence of reflex reactions of adjacent innervated organs and are often caused by severe intestinal paresis.

Increased body temperature, leukocytosis and other general manifestations of renal colic are caused by renal pelvis reflux.

Another characteristic symptom of urolithiasis is hematuria. It occurs in all phases of the disease, with the exception of the period of complete obstruction of the ureter. A characteristic difference for hematuria in urolithiasis is that hematuria often increases during movement and decreases at rest. This hematuria is not abundant, most often it is detected as microhematuria; usually without the formation of blood clots.

Leukocyturia and pyuria are important symptoms indicating complications of urolithiasis with infection. However, even with aseptic stones, a general urine analysis can often reveal up to 20-25 leukocytes in the field of view.

Spontaneous passage of a stone with urine is the most reliable symptom proving the presence of the disease. Usually, the passage of a stone is preceded by an attack of renal colic, increased dull pain or dysuria.

In the remission phase, urolithiasis may not show symptoms and when prescribing preventive treatment, the doctor relies on examination data.

Forms

In coral nephrolithiasis, the calculus completely occupies the renal pelvis. There are calcium (carbonate), oxalate, urate, and phosphate nephrolithiasis. Less common are cystine, xanthine, protein, and cholesterol stones.

The clinical form of urolithiasis determines the severity of the disease and the choice of treatment method.

Depending on the shape and location of the urinary stone in the urinary system, a clinical classification was developed.

• By number of stones:
  • single urinary stone;
  • multiple urinary stones;
  • coral urinary stones.
• By frequency of occurrence:
  • primary;
  • recurrent (true recurrent, false recurrent);
  • residual.
• By character:
  • infected;
  • uninfected.
• By location of urinary stone:
  • cups;
  • stone
  • bilateral urinary calyceal stones;
  • upper third of the ureter;
  • middle third of the ureter;
  • lower third of the ureter;
  • bladder;
  • urethra.

In the European Association of Urologists, when diagnosing urinary ureteral stones, it is customary to indicate one of three zones of their localization (upper, middle and lower third); in the American Association - one of two, upper or lower.

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Diagnostics urolithiasis

A carefully collected anamnesis allows in 80% of cases to choose the right direction for urolithiasis diagnostics. When communicating with the patient, special attention is paid to possible risk factors. During a physical examination, including palpation, it is possible to detect pain in the affected kidney when tapping on the lower back (positive Pasternatsky symptom).

Patients with renal colic caused by the passage of a stone usually complain of intense paroxysmal pain in the lower back, nausea, vomiting, chills, and subfebrile body temperature. When the stone is localized in the lower third of the ureter, patients experience imperative urges to urinate, and pain radiating to the groin area. Clinical diagnosis is established based on data from various methods of stone visualization (radiological diagnostics).

It should be noted that the diagnosis of urolithiasis is based on visualization methods, since the physical urological symptoms of urolithiasis are characteristic of many diseases. Renal colic often has to be differentiated from acute appendicitis, cholecystitis, colitis, radiculitis, etc. Modern diagnostics of urolithiasis in 98% of clinical observations allow us to correctly diagnose various clinical forms of urolithiasis.

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Laboratory diagnostics of urolithiasis

A general blood test allows us to judge the signs of the onset of inflammation: leukocytosis, a shift in the leukocyte formula to the left with an increase in the number of band neutrophils, and an increase in ESR are noted.

Clinical analysis of urine reveals micro- or macrohematuria, crystalluria, leukocyturia, bacteriuria, and changes in urine pH.

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Laboratory tests for uncomplicated urolithiasis

Analysis of the chemical composition of the calculus

• Should be performed on every patient.

Biochemical blood test

• The concentration of free and ionized calcium, albumin is determined; as additional indicators - the concentration of creatinine, urates

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Urine analysis

Analysis of morning urine with sediment examination:

• studies using a special test system (pH, number of leukocytes, bacteria, cystine content, if cystinuria cannot be excluded by other means);
• Bacterial culture testing for bacteriuria

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Research in complicated urolithiasis

Analysis of the chemical composition of the calculus

• Should be performed on every patient.

Biochemical blood test

• The concentration of free and ionized calcium, albumin is determined; as additional indicators - the concentration of creatinine, urates, potassium

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Urine tests

Analysis of morning urine with sediment examination:

• studies using a special test system (pH, number of leukocytes, bacteria, cystine level, if cystinuria cannot be excluded by other means);
• Bacterial culture study to detect bacteriuria.

Daily urine test:

• determination of the concentration of calcium, oxalates, citrates;
• determination of urate concentration (in samples not containing oxidizer);
• determination of creatinine concentration;
• determination of urine volume (daily diuresis);
• determination of magnesium concentration (additional analysis; necessary to determine the ionic activity in ionized Ca products);
• determination of phosphate concentration (additional analysis, necessary to determine the ionic activity in calcium phosphate products, the concentration depends on the patient's dietary preferences):
• determination of the concentration of urea, potassium, chlorides, sodium (additional tests; concentrations depend on the patient's dietary preferences)

Qualitative and quantitative analysis of urinary stones is carried out using infrared spectrophotometry and X-ray defractometry. Analysis of the elemental and phase composition of urinary stones is an obligatory element of modern diagnostics of urolithiasis, since knowledge of the chemical structure of the pathogenesis of the disease and metabolic disorders that have arisen in the body allows for the development of adequate medical conservative therapy.

Instrumental diagnostics of urolithiasis

Mandatory examination includes a general X-ray of the abdomen (area of the kidneys, ureters and bladder). The method allows diagnosing X-ray-positive stones. The sensitivity of the method is 70-75% (may decrease with aerocoly, increased patient weight) specificity is 80-82%.

Ultrasound of the kidneys allows us to judge:

• direct representation of the kidney stone and prevesical part of the ureter;
• indirect representation of the expansion of the renal pelvis and calyces, proximal and distal ureter.

Ultrasound allows to evaluate parenchymal edema, to identify foci of purulent destruction and the index of resistance of renal arteries. The diagnostic significance depends on the class of ultrasound equipment and the professionalism of the doctor, on average, the sensitivity of ultrasound of the kidneys is 78-93%. Specificity - 94-99%.

Excretory urography is performed after complete relief of renal colic. The method provides an adequate idea of the anatomical and functional state of the urinary system. The interpretation of the results is influenced by the same factors as the survey image. The sensitivity of the method is 90-94%. Specificity - up to 96%.

Excretory urography is not prescribed to patients:

• taking metformin;
• patients with myelomatosis;
• with an allergic reaction to contrast agent;
• with a serum creatinine level of more than 200 mmol/l.

MSCT is performed in the following cases:

• suspected urate nephrolithiasis;
• complex form of coral nephrolithiasis;
• if there is a suspicion of a urinary tract tumor;
• if the stone is not diagnosed by other research methods

MSCT allows for virtual reconstruction of the obtained images and assessment of the density of the stone, which in turn helps determine indications or contraindications for DLT.

The sensitivity and specificity of the method are close to 100%.

Additional examination includes:

• retrograde or antegrade ureterography, pyelography (allows to diagnose the patency of the ureter along its entire length);
• dynamic scintigraphy for separate and segmental examination of the secretory and evacuation functions of the kidneys;
• aortography to analyze the angioarchitecture of the kidney, which is especially important when planning repeat operations (2-3 operations) for coral nephrolithiasis, when conflicts with the vessels are possible during their isolation.

Indications for consultation with other specialists

For more effective treatment, it is very important to promptly refer the patient for consultation with an endocrinologist, nutritionist, or gastroenterologist.

Example of diagnosis formulation

A correctly formulated diagnosis allows the specialist to most fully present the overall picture of the disease. Until now, one often encounters extracts in which the diagnosis sounds like this: "Right kidney stone. Chronic pyelonephritis."

At the same time, using the accepted classification of urolithiasis and the comprehensive examination of the patient, this diagnosis should have been formulated as follows: “Primary single oxalate stone of the renal pelvis (2.0 cm) of a functionally intact uninfected right kidney”;

"False-recurrent, clinically asymptomatic urate stone (size, diameter up to 6 mm) of an isolated lower calyx of a secondarily shrunken right kidney."

In addition, a single agreed presentation of the diagnosis is a mandatory condition for the transition of domestic healthcare to insurance-based medicine.

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Differential diagnosis

Differential diagnostics of urolithiasis and renal colic complicated by obstructive pyelonephritis is carried out with:

• acute appendicitis;
• acute cholecystitis;
• perforated ulcer of the stomach or duodenum;
• acute obstruction of the small or large intestine;
• acute pancreatitis;
• ectopic pregnancy;
• diseases of the spine.

A distinctive feature of the urological nature of the disease is the absence of symptoms of peritoneal irritation observed in gastrointestinal diseases.

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Treatment urolithiasis

Treatment of urolithiasis begins immediately when recurrent pain occurs; the use of morphine and other opiates is avoided without the simultaneous administration of atropine.

Drug treatment of urolithiasis

Treatment of urolithiasis begins immediately when recurrent pain occurs; the use of morphine and other opiates is avoided without the simultaneous administration of atropine.

Pain can be relieved with various combinations of the following drugs: diclofenac, indomethacin, ibuprofen, morphine, metamizole sodium and tramadol.

Diclofenac reduces the glomerular filtration rate in patients with renal failure, but this does not occur in patients with normal renal function.

If spontaneous passage of the calculus is possible, 50 mg of diclofenac in suppositories or tablets is prescribed twice a day for 3-10 days to relieve pain, reduce the risk of its recurrence, and reduce ureteral edema. The movement of the calculus and the assessment of renal function should be confirmed by appropriate methods.

According to the European Association of Urologists, with a stone size of 4-6 mm, the probability of spontaneous passage is 60%:

• upper third of the ureter - 35%;
• middle third of the ureter - 49%;
• lower third of the ureter - 78%.

According to the American Urological Association, 75% of ureteral stones pass spontaneously:

• for stones up to 4 mm - 85%;
• for stones larger than 4-5 mm - 50%;
• stone more than 5 mm - 10%.

However, even small stones (up to 6 mm) may be an indication for surgical removal in the following cases:

• lack of effect despite adequate treatment of urolithiasis;
• chronic urinary tract obstruction with risk of renal dysfunction;
• infectious diseases of the urinary tract;
• inflammatory process, risk of developing urosepsis or bilateral obstruction.

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Surgical treatment of urolithiasis

Basic recommendations for removing stones

Patients who are scheduled to have a calculus removed are prescribed:

• urine culture;
• testing the isolated bacterial culture for sensitivity to antibiotics;
• general clinical blood test;
• creatinine clearance.

If the bacteriuria test is positive or urine culture shows bacterial growth or infection, the patient is given antibiotics before surgery. If clinically significant infection is confirmed or if urinary tract obstruction is present, the kidney is drained by stenting or percutaneous needle nephrostomy for several days before surgery.

Extracorporeal lithotripsy, percutaneous lithotripsy, ureteroscopy and open surgery are contraindicated in patients with hemostatic disorders.

Indications for active removal of stones

The size, shape, location of the calculus and the clinical course of the disease determine the strategy for treating urolithiasis. A clinically silent single calyceal stone (up to 1.0 cm) or a coral-shaped calyceal stone that does not disrupt the secretory and evacuation functions of the kidney and does not lead to the progression of pyelonephritis are not an indication for their surgical removal. At the same time, any stone that causes pain to the patient, social discomfort, disrupts the functioning of the urinary system, and leads to the death of the kidney is an indication for its surgical removal.

Extracorporeal shock wave lithotripsy

It is often necessary to perform several sessions of remote lithotripsy when using it as monotherapy (remote lithotripsy in situ). Large and "driven in" or long-term located in one place of the ureter stones (more than 4-6 weeks) require the maximum number of sessions of remote lithotripsy and the use of additional therapeutic measures, therefore, in such a situation, contact ureterolithotripsy comes to the fore. Today, the American and European Associations of Urologists have developed a fundamentally unified tactic in choosing a method for removing ureteral stones.

Videoendoscopic retroperitoneal surgery is a minimally invasive alternative to open surgery, although both of these methods are indicated only in cases where extracorporeal lithotripsy and contact ureterolithotripsy are not feasible. At the same time, evaluating the effectiveness of extracorporeal lithotripsy and contact ureterolithotripsy separately and their combination, which allows achieving the removal of ureteral stones with an efficiency of up to 99%, indications for laparoscopy and open surgery are extremely rare today.

Principles of Active Kidney Stone Removal

The success of remote lithotripsy depends on the physicochemical properties of the calculus and the anatomical and functional state of the kidneys and upper urinary tract. Remote shock wave lithotripsy is a non-invasive and least traumatic method for removing urinary stones.

All modern lithotripters, regardless of the source of shock wave generation, create a shock wave impulse which, without damaging biological tissues, has an alternating effect on the stone, gradually leading to its destruction into a finely dispersed mass with subsequent spontaneous passage through the urinary tract.

In 15-18% of cases, remaining fragments of the stone up to 3-4 mm in size are noted, which leads to the formation of a “stone path” in the ureter.

Stones up to 2.0 cm are considered optimal for remote lithotripsy. For larger stones, preliminary installation of an internal catheter "Stent" before remote lithotripsy is recommended in order to avoid accumulation of stone fragments in the ureter.

A necessary condition for increasing the efficiency and reducing the trauma of a remote lithotripsy session is the ideally precise removal of the stone into the focal zone under X-ray or ultrasound guidance.

Comparative table of methods of visualization and focusing of stone

Method	Advantages	Flaws
X-ray	Ease of execution The ability to obtain a complete image of the kidney and ureter, as well as to observe the degree of stone destruction and displacement of fragments	Patient and staff irradiation The dependence of the obtained result on the patient's body weight, as well as on the aerocoly
Ultrasound	No radiation. Continuous monitoring of the stone crushing process. Visualization of radiolucent stones Small stones are more visible	More complex execution Does not allow obtaining an image of the middle third of the ureter and fully observing the process of stone fragmentation

To crush one stone up to 2 cm in size in an adult, 1500-2000 impulses (1-2 sessions) are required; in children, 700-1000 impulses, since almost all stones have a lower density.

Mixed stones are easier to destroy than monostructural ones. Cystine stones are the most difficult to crush.

Large stones require the use of higher energy pulses and several crushing sessions or the performance of remote lithotripsy after preliminary installation of a stent catheter or percutaneous nephrolithotripsy.

The measures that ensure the effectiveness of remote lithotripsy include:

• special training of a physician;
• correct prescription of remote lithotripsy (optimal size of stones up to 2.0 cm);
• accuracy of stone placement into the focal zone of the shock wave during the session;
• initial knowledge of the physical and chemical properties of the stone and the functional state of the kidney;
• compliance with the technology of using shock wave impulses.

Contraindications for the appointment of remote lithotripsy:

• the possibility of bringing the calculus into the focus of the shock wave (obesity, deformation of the musculoskeletal system);
• blood coagulation disorder;
• severe intercurrent cardiovascular diseases;
• acute gastrointestinal diseases;
• inflammatory diseases of the urinary tract;
• strictures below the site of the stone;
• marked decrease in kidney function (more than 50%).

Complications during remote lithotripsy are very rare; sometimes obstruction of the ureter by fragments of a destroyed stone (18-21%), obstructive pyelonephritis (5.8-9.2%), and renal hematomas (0.01%) are noted.

To prevent and eliminate complications:

• perform urinary tract sanitation before remote lithotripsy;
• strictly adhere to the methods of performing remote lithotripsy, taking into account the clinical course of urolithiasis;
• in case of a complex form of urolithiasis, a catheter is first installed or a puncture nephrostomy is performed;
• promptly drain the kidney when obstructive complications develop.

Contact ureterolithotripsy

Endoscopic transurethral and percutaneous lithotripsy and lithoextraction allow not only to destroy but also remove the entire stone under visual control, as well as to eliminate short obstruction below the location of the stone - balloon dilation, endoureterotomy, endopyelotomy. The effectiveness of endoscopic methods in removing stones is not inferior to remote lithotripsy, and in the case of large stones and complex stones even exceeds it. The debate about the choice of method for removing large kidney stones is still ongoing: remote lithotripsy or contact ureterolithotripsy?

However, the complexity of performing transurethral contact ureterolithotripsy for prostate adenoma, ureteral deviations, and the relatively high percentage of complications bring to the forefront the use of remote lithotripsy.

In addition, it is undesirable to use contact ureterolithotripsy in children (especially in boys), and in 15-23% of cases during this procedure (especially with stones in the upper third of the ureter), the stones migrate to the kidney, which requires subsequent remote lithotripsy.

At the same time, contact ureterolithotripsy in 18-20% of cases allows to eliminate "stone paths" formed after remote lithotripsy. Thus, remote lithotripsy and contact ureterolithotripsy are modern complementary minimally invasive methods of removing ureteral stones, allowing to achieve 99% efficiency.

The development of flexible and thin rigid endoscopes and less traumatic lithotripters (Lithoclast, laser models) contributed to a reduction in the number of complications and increased the effectiveness of contact ureterolithotripsy.

Complications and failures of contact ureterolithotripsy include:

• inability to bring the ureteroscope to the stone (pronounced deviation, periureteritis below the location, bleeding), migration of the stone into the kidney (10-13%);
• trauma to the ureteral orifice at the stage of bougienage (1-3%);
• perforation of the ureter with both a guidewire and a ureteroscope (3.8-5 o),
• acute pyelonephritis as a result of an undiagnosed infectious disease of the urinary system, increased pressure of the irrigation solution, failure to observe asepsis (13-18%);
• acute prostatitis (4%);
• ureteral avulsion (0.2%).

To prevent complications after contact ureterolithotripsy, a number of requirements are observed.

• Operation performed by certified qualified personnel with sheets.
• Comprehensive and anti-inflammatory preoperative preparation for contact ureterolithotripsy.
• Preoperative drainage of the kidney during percutaneous lithotripsy in cases of long-standing and large ureteral stones with urethrohydronephrosis above the location of the calculus.
• The use of a guidewire is mandatory during urethroscopy.
• It is necessary to drain the kidney with a catheter or stent after contact ureterolithotripsy for 1-3 days. In case of short-term contact ureterolithotripsy, surgery without orifice bougienage and atraumatic removal of a small stone, a catheter may not be installed.

Treatment of complications that arise after contact ureterolithotripsy:

• mandatory drainage of the kidney by puncture nephrostomy and installation of an internal stent;
• active anti-inflammatory detoxification therapy against the background of drainage in the development of acute pyelonephritis;
• open surgery (ureteroureteroanastomosis, nephrostomy and ureteral intubation) in case of ureteral rupture.

Percutaneous nephrolithotripsy and lithoextraction

Percutaneous nephrolithotripsy and lithoextraction are the most effective method for removing large, coral-shaped and complicated kidney stones.

The disadvantages of percutaneous nephrolithotripsy include its invasiveness, the need for anesthesia, and trauma both at the stage of kidney drainage and directly during the session. As a result, there is a high risk of complications, especially at the stage of mastering the method.

Improvement of endoscopic equipment and instruments for kidney drainage have significantly reduced the risk of traumatic complications. Qualified training of the urologist, knowledge of topographic anatomy and mastery of ultrasound diagnostic methods are mandatory for the effective conduct of the operation, since the effectiveness of the result of percutaneous nephrolithotripsy and the percentage of complications depend on the most important stage of the operation - the creation and blocking of the working passage (drainage of the kidney).

Depending on the location of the stone, the entrance to the renal pelvis is through the lower, middle or upper group of cups.

In case of coral or multiple stones, two puncture channels can be used. To facilitate visualization of the renal pelvis and to prevent migration of destroyed fragments into the ureter, catheterization of the renal pelvis with pyelography is performed before the operation. Using an electrohydraulic, ultrasound, pneumatic, electropulse or laser lithotripter, the stone is destroyed and lithoextraction of fragments is performed simultaneously. A special casing allows, without losing the nephrotomy tract, not only to remove large fragments, but also prevents an increase in intrapelvic pressure.

The development of miniature endoscopic instruments has made it possible to significantly expand the indications for the use of percutaneous nephrolithotripsy, even in younger children.

According to Prof. A.G. Martov (2005), the effectiveness of percutaneous nephrolithotripsy in children with coral stones was 94%. Percutaneous nephrolithotripsy in children is performed only by endoscopists who have sufficient experience in performing percutaneous operations in adults.

The operation ends with the installation of a Foley or Malecot type nephrostomy drainage tube through the nephrotomy tract with a diameter no less than the diameter of the nephroscope.

Complications of percutaneous nephrolithotripsy at the puncture stage include:

• puncture through the renal pelvis or intercervical space;
• injury to large vessels during puncture or bougienage;
• injury to the pleural cavity or abdominal organs, through perforation of the renal pelvis;
• formation of a subcapsular or paranephric hematoma.

During and after percutaneous nephrolithotripsy, the following complications are possible:

• loss of nephrotomy tract and the need for repeated punctures;
• injury to the mucous membrane of the renal pelvis or intercervical space with the development of bleeding;
• creation of uncontrolled increased pressure in the renal pelvis;
• acute pyelonephritis;
• tamponade of the renal pelvis with blood clots;
• discharge or inadequate function of nephrostomy drainage.

To prevent complications after percutaneous nephrolithotripsy, a number of requirements are observed.

• It is necessary to conduct qualified, certified training of specialists in endourology.
• Knowledge of ultrasound diagnostic techniques minimizes the percentage of complications at the puncture stage.
• The installation of a safety string in the renal pelvis allows the nephrotomy tract to be established in any situation.
• Uncontrolled administration of irrigation solutions is unacceptable.
• Preoperative antibacterial treatment of urolithiasis, compliance with aseptic rules and adequate function of nephrotomy drainage reduces the risk of acute pyelonephritis to zero.

In the case of progressively increasing hematomas, bleeding or purulent-destructive pyelonephritis, open surgery is indicated (revision of the kidney, suturing of bleeding vessels, decapsulation of the kidney).

For stones larger than 2.0 cm or high-density stones that are difficult to treat with EBRT, percutaneous stone removal is the best alternative in the treatment of urolithiasis. The effectiveness of one-stage PNL reaches 87-95%.

For removal of large and coral stones, a high percentage of efficiency is achieved by the combined use of percutaneous nephrolithotripsy and DLT - 96-98%. At the same time, the low density of urinary stones and the high efficiency of DLT, the rapid passage of fragments through the urinary tract make the method a priority even when crushing large kidney stones. A study of the long-term results (5-8 years) of the use of DLT in children did not reveal any traumatic kidney injury in any patient.

In cases where minimally invasive methods (ESL, contact ureterolithotripsy, percutaneous nephrolithotripsy) cannot be prescribed for technical or medical reasons, patients undergo open surgery:

• pyelolithotomy (anterior, posterior, inferior);
• pyelonephrolithotomy;
• anatrophic nephrolithotomy;
• ureterolithotomy;
• nephrectomy (for a shrunken kidney, pyonephrosis, multiple carbuncles or kidney abscesses).

Complications of open surgeries can be divided into general and urological. General complications include exacerbation of concomitant diseases: coronary heart disease (5.6%), gastrointestinal bleeding (2.4%), pleuropneumonia (2.1%), thromboembolism (0.4%).

The most attention is drawn to intraoperative complications: iatrogenic injuries to nearby organs (9.8%), bleeding in a volume of more than 500 ml (9.1%), acute pyelonephritis (13.3%), urinary leakage (1.8%), suppuration of the surgical wound (2.1%), postoperative strictures (2.5%).

Prevention of complications after open surgeries:

• performance (especially of repeated operations) by highly qualified urologists contributes to minimal trauma to the renal parenchyma during surgery;
• performing pyelonephrolithotomy with a compressed renal artery;
• adequate drainage of the kidney with a nephrostomy drainage of sufficient diameter 16-18 CH with its fixation to the parenchyma and skin;
• hermetic suturing of the renal pelvis incision, ligation of injured vessels;
• careful care and monitoring of the nephrostomy drainage system.

The highest percentage (up to 75%) of complications is observed during repeated operations, when the topographic anatomy of the retroperitoneal space changes due to cicatricial processes.

Treatment of calcium urolithiasis

Treatment of urolithiasis should begin with conservative measures. Pharmacological treatment is prescribed only when the conservative regimen has proven ineffective.

For a healthy adult, the daily urine volume should be 2000 ml, but the urine hypersaturation level indicator should be used, reflecting the degree of dissolution of stone-forming substances in it.

The diet should contain a variety of foods, different in chemical composition; it is necessary to avoid excess nutrition. Nutritional recommendations should be created taking into account the individual metabolic disorders of each patient.

Taking thiazides increases calcium reabsorption in the proximal and distal tubules, reducing its excretion in urine. An alternative may be the prescription of orthophosphates (crystallization inhibitors) and prostaglandin inhibitors (diclofenac, indomethacin). The prescription of sodium bicarbonate (4-5 mg per day) is recommended for patients whose treatment of urolithiasis with citrate mixtures has not yielded the desired result.

In patients with magnesium ammonium phosphate and carbonate apatite stones caused by urease-producing microorganisms, maximum removal of stones should be achieved during surgery. Antibacterial treatment of urolithiasis should be prescribed according to urine culture data; long courses of antibacterial therapy are recommended for maximum sanitization of the urinary tract.

Treatment of urate urolithiasis

Uric acid stones can be prevented by prescribing the patient to drink more fluids (diuresis should be more than 2000 ml per day). Normalization of uric acid levels can be achieved by strictly following a diet. Increasing plant products and decreasing meat products containing a high concentration of purines will help prevent recurrence of stone formation.

To alkalinize the urine, 3-7 mmol potassium bicarbonate and/or 9 mmol sodium citrate are prescribed twice or three times daily. In cases where serum urate or uric acid levels are elevated, 300 mg allopurinol per day is used. To achieve dissolution of uric acid stones, it is necessary to prescribe large amounts of oral fluids, as well as 6-10 mmol potassium bicarbonate and/or 9-18 mmol sodium citrate three times daily and 300 mg allopurinol in cases where serum and urinary urate levels are normal.

Chemical dissolution of ammonium urate stones is impossible.

Treatment of cystine urolithiasis

Daily fluid intake should be more than 3000 ml. To achieve this, it is necessary to drink 150 ml of fluid every hour. Alkalinization should be carried out until the urine pH is consistently above 7.5. This can be achieved by using 3-10 mmol of potassium bicarbonate divided into 2-3 doses.

Indications for consultation with other specialists

The formation of stones in the urinary tract is a pathological condition that affects people of different age groups in most countries of the world. The recurrent nature of the disease, often severe complications and disability of patients give great medical and social significance to this disease.

Patients with urolithiasis should be under constant dispensary observation and undergo treatment for urolithiasis for at least 5 years after complete removal of the stone. Correction of metabolic disorders should be carried out by urologists with the involvement of endocrinologists, nutritionists, gastroenterologists, and pediatricians in the educational process.

For successful recovery, it is important not only to remove the stone from the urinary tract, but also to prevent recurrence of stone formation, prescribing appropriate therapy aimed at correcting metabolic disorders for each individual patient.

The least invasive technologies for removing stones, widely introduced into medical practice, have made one of the stages of therapy relatively safe and routine.

Prevention

Urolithiasis is prevented by pharmacological and dietary correction. Increasing diuresis to 2.5-3 liters by expanding the drinking regime is recommended for all types of the disease. In urate, calcium and oxalate lithiasis, an increase in the consumption of potassium and citrates is indicated. Citrates, alkalizing urine, increase the solubility of urates, and also bind calcium in the gastrointestinal tract, thereby reducing the recurrence of calcium nephrolithiasis. It is necessary to limit animal protein and salt in the diet, as well as products containing substances involved in the formation of stones. Thus, in urate lithiasis, meat products rich in purines, alcohol are excluded, in oxaluria - sorrel, spinach, rhubarb, legumes, capsicum, lettuce, chocolate.

Substitution of animal proteins with plant proteins (soy products) increases calcium binding in the gastrointestinal tract and reduces its concentration in urine, while in case of calcium nephrolithiasis, calcium intake should not be sharply limited: a low-calcium diet increases calcium absorption in the gastrointestinal tract, increases oxaluria and can induce osteoporosis. To reduce hypercalciuria, thiazides are used (hydrochlorothiazide 50-100 mg/day monthly and in courses 5-6 times a year) under the control of the level of uric acid, calcium and potassium in the blood. In case of severe hyperuricosuria, allopurinol is prescribed. The use of allopurinol is also effective for the prevention of calcium oxalate nephrolithiasis.

[ 68 ], [ 69 ], [ 70 ], [ 71 ], [ 72 ], [ 73 ], [ 74 ]