Prostate adenoma: surgery

Among the variety of methods currently offered for the treatment of prostate adenoma (prostate), the operation "open adenomectomy" remains the most radical way of treating this disease.

Result of rapid development of methods of conservative therapy of prostate adenoma was the revision of indications for surgical treatment. Currently, the operation is considered unconditionally indicated only in the presence of complications of the disease. According to the recommendations of the 3rd meeting of the International Conciliation Committee on the problem of prostate adenoma (1995), absolute indications for surgical treatment are defined:

• delay urination (inability to urinate after even a single catheterization):
• repeated massive hematuria associated with prostate adenoma;
• renal failure due to prostate adenoma;
• stones of the bladder;
• repeated infection of the urinary tract due to prostate adenoma;
• large diverticulum of the bladder.

In addition, the operation is shown to patients, the prognosis of prostatic adenoma (prostate gland) in which it does not allow to expect a sufficient clinical effect from conservative methods (the presence of an increased average prostate share, pronounced infravesical obstruction, a large amount of residual urine) or if already conducted medication does not give necessary result. In other cases, conservative treatment may be recommended as the first stage.

Operation with adenoma of the prostate (prostate gland) can be undertaken for emergency indications or in a planned manner. Under urgent adenomectomy, it is meant to be performed outside the routine work on urgent indications. Urgent adenomectomy is emergency, when it must be performed within 24 hours from the acute onset of the disease (complications), and urgent, when it must be performed no later than 72 hours from the moment the patient enters the urological department.

[1], [2], [3], [4], [5], [6], [7],

Operation "emergency adenomectomy"

The operation "emergency adenomectomy" is shown:

• with life-threatening bleeding;
• with acute retention of urination and the general satisfactory state of the patient.

Acute urinary retention rarely passes by itself. In most cases, bladder catheterization is a forced measure.

Urgent adenomectomy is contraindicated in the presence of an acute inflammatory process in the urinary system, concomitant diseases in the stage of decompensation (stage III hypertension, chronic ischemic heart disease, diabetes mellitus, etc.), terminal stage of chronic renal failure.

The nature and purpose of preoperative preparation is determined by those deviations in the patient's state of health that must be eliminated in order to reduce the risk of complications and the severity of the postoperative period. In the presence of changes in the cardiovascular and respiratory system, appropriate medical therapy is carried out. Much attention is paid to the treatment of concomitant infection of the kidneys and urinary tract. To do this, patients are prescribed uroantiseptics and broad-spectrum antibiotics according to the sensitivity of the urine microflora, giving preference to the least nephrotoxic drugs. The condition of the blood coagulability system is examined and appropriate treatment is prescribed to prevent postoperative complications. In the presence of diabetes, antidiabetic therapy is performed, and if necessary, the patients are transferred to insulin injections. In the presence of concomitant chronic prostatitis before the operation, it is important to conduct an appropriate course of therapy.

A detailed description of the technique of various methods of operative treatment of prostate adenoma is given in special monographs and manuals on operative urology, therefore in this manual we will only consider general and principled positions.

Depending on the access to the prostate, there are chespuzubrusnuyu, retropubic, and transurethral adenomectomy.

Transurethral endourological treatment of prostate adenoma

During the last decade, TUR adenomas of the prostate are increasingly being introduced into clinical practice. The use of transurethral surgery significantly increased the indications for surgical treatment of patients with prostatic adenoma and concomitant intercurrent diseases, which until recently were doomed to lifelong urinary diversion by cystostomy. Perfection of endoscopic equipment and accumulated experience allowed to expand the capabilities of TUR and to apply this method in patients with large prostate adenoma (more than 60 cm ² ), as well as in retrotrigonal growth, which was previously a contraindication to this operation. The TOUR of the prostate can be performed both in a planned manner and under emergency indications (with an acute delay in urination).

Among the various methods of treating prostate adenoma, TUR currently occupies a leading position, which is undoubtedly due to its low traumatism and high efficiency. This method of surgical treatment has a number of advantages over an open surgery.

• No soft tissue injury when accessing the prostate.
• Clearly controlled hemostasis during surgery.
• Less prolonged rehabilitation of patients in the postoperative period.
• The possibility of surgical treatment in persons with intercurrent diseases.

To carry out the TUR, a certain instrumental and technical support is needed.

In the early postoperative period of TURP, it is also possible to develop bleeding associated with local fibrinolysis in prostate tissue or systemic intravascular coagulation.

Late hemorrhages (on the 7th-8th, 13th-14th, 21st day) are most often associated with the departure of the postoperative scab. They, as a rule, have intermittent flow and in most cases they can be managed conservatively (haemostatic therapy, establishment of a urethral catheter with tension). With non-occlusive bleeding within a day, a repeated endoscopic intervention aimed at coagulation of bleeding vessels is indicated. In the pathogenesis of late bleeding an important role is played by the presence of chronic infection in the prostate, as well as the resulting purulent-inflammatory complications in the immediate postoperative period, contributing to inhibition of wound healing and early removal of the scab. Given this, all patients with a history of chronic infection of the lower urinary tract in the anamnesis need to conduct preoperative preparation in the form of antibiotic therapy, taking into account the etiology.

One of the terrible postoperative complications of TURP is the development of water intoxication (TUR syndrome), the frequency of which varies from 0.5 to 2%. In the pathogenesis of the TUR syndrome, the main role is played by the inflow into the bloodstream of a large amount of irrigation fluid during endoscopic surgery through the intersected venous vessels of different calibers when used for irrigation of the bladder during the operation of hypoosmolar solutions. The longer the operation lasts, the more the amount of fluid absorbed and the larger the diameter of the venous trunks, the more fluid can enter the venous collectors, determining the degree of water intoxication of the body. Consequently, an unrecognized venous sinus injury increases the likelihood of this complication. TUR-syndrome is manifested by a number of symptoms that arise already in the early postoperative period (during the first day). This bradycardia, lower blood pressure, changes in biochemical parameters and electrolyte blood composition (hyponatremia, hypokalemia) on the background of hypervolemia. Several stages can be distinguished in the development of the TUR syndrome. The initial manifestations, which should alert the urologist already during the operation, is considered an increase in blood pressure, the appearance of chills. If you do not take the necessary measures to correct this condition, then in the future note its sharp deterioration: a drop in blood pressure, massive hemolysis of red blood cells, development of oligoanuria. General anxiety, cyanosis, dyspnea, chest pain and seizures. In the absence of effect from the ongoing therapy of acute renal and hepatic insufficiency and gross electrolyte disturbances, the patient's death occurs.

When a TUR syndrome occurs, urgent conservative measures are needed to normalize the water-electrolyte balance and stabilize hemodynamics. For prevention of TUR-syndrome it is necessary:

• use only isotonic wash solutions;
• strive to reduce the time of operation due to improved visibility (the use of high-quality optical equipment, video-TUR). Perfection of skill of the urologist;
• strictly adhere to the principles of performing TURP prostate.

In addition, in order to prevent an increase in intravesical pressure, it is recommended to use resectoscopes with permanent irrigation of the fluid, special mechanical valves, active aspiration systems,

Among the inflammatory complications that occur after the TUR of the prostate, acute inflammatory diseases of the lower urinary tract and scrotum organs (urethritis, funiculitis, epididymoorkhitis, prostatevisculitis, cystitis) occupy the place, the cause of which is most often associated with exacerbation of a chronic infectious process against the background of the urethral catheter.

It is necessary to stop and on other complications TUR of the prostate is not the last place among which the iatrogenic injuries of the urinary tract are occupied. These are bladder injuries (perforation of the wall, damage to the Lieto triangle), damage to ureteral orifices, often occurring during resection of expressed intravesical lobes of hyperplastic prostate, damage to the urethra and prostate , which can cause a stricture of the urethra, a violation of the integrity of the external sphincter of the urethra, with leading to urinary incontinence, damage to the seed tubercle. Most often they arise at the stage of mastering the TUR technique when the technique of performing the operation is not observed, so the necessity of strict adherence to all the rules of transurethral interventions and the existence of a certain experience that allows the urologist to avoid these complications is obvious.

Among the late complications of TURP prostate is to note the stricture of the urethra and the sclerosis of the neck of the bladder. The stria of the urethra often occurs in the forelegs and is associated with three major factors: trauma of the mucosa during the endoscope's passage through the urethra, inflammatory changes in the urethra, and chemical damage to the urethra caused by the urethral catheter. Sclerosis of the neck of the bladder after TUR of the prostate is less common than after open adenomectomy. But the frequency of its occurrence is relatively high (8-15%). Most often this complication occurs in patients after TUR with small adenomas combined with chronic bacterial prostatitis.

As with other surgical procedures on the prostate, there is a risk of retrograde ejaculation with a frequency of 75 to 93% of cases in TUR, which must be taken into account when determining operative tactics in patients with a preserved sexual function.

Transurethral electrovaporization of the prostate

Along with TUR, a new method of treatment of prostate adenoma - electroporation (or electric evaporation) of the prostate is being introduced more and more recently. This method is based on the TUR technique using a standard endoscopic kit. The difference lies in the use of a new roller electrode (vaportrod, or roller), represented by several modifications, differing direction of energy distribution. In contrast to TUR, when electrovaporization occurs in the contact zone of the roller electrode with the prostate tissue, the tissue is evaporated with simultaneous drying and coagulation. By analogy with TUR, this operation can be called transurethral electro-vaporation of the prostate.

The current used for electropolarisation is 25-50% greater than with the standard TUR. The depth of coagulation with transurethral electro-evaporation is approximately 10 times higher than that of TUR, which significantly reduces the bleeding of the tissue during surgery. This advantageously distinguishes this treatment from TUR, which is accompanied by bleeding of varying intensity during the operation.

Due to the fact that the technician of the operation of transurethral electro-evaporation does not presuppose obtaining a material for histological examination with the aim of excluding latent prostate cancer, all patients need to conduct a serum blood test for the content of PSA. In the case of its increase before the operation, preliminary fine-needle multifocal prostate biopsy is shown.

Indications for transurethral electro-evaporation are the same as for TUR. Most often, epidural anesthesia is used to provide adequate analgesia during transurethral electro-evaporation. After surgery, the urethral catheter is set for 1-2 days.

The results of using transurethral electro-evaporation proved its effectiveness at small and medium sizes of the prostate, which allows treating this method of treatment as independent in this category of patients.

Electrointestion of prostate adenoma

Along with transurethral electroresection and electrovaporization, a wide range of other methods of electrosurgical treatment have recently been widely used: electrosurgery of the prostate. The method was proposed by E. Beer in 1930, but spread only in the 70s, when it was relatively widely used instead of TUR in patients with prostate adenoma and sclerosis of the neck of the bladder. In contrast to TUR, in which electrosurgical tissue removal is performed around the circumference by means of a cutting loop, the prostate tissue and the bladder neck are not removed during incision, but longitudinal incision is performed. Thus, with the incidence of the prostate, the need for a biopsy of the prostate in the preoperative period is evident with suspicion of a malignant process.

Indications for prostate dissection:

• young age of the patient with preserved sexual function;
• a small volume of the prostate (weight of the gland should not exceed 20-30 g);
• the distance from the seminal tubercle to the neck of the bladder is not more than 3.5-4.0 cm:
• predominantly intravesical growth of the adenoma;
• absence of malignant lesion of the prostate.

Electro-cinch is produced at 5, 7 and 12 hours on the conventional dial with a spear-shaped electrode. The incision is performed through the entire thickness of the hyperplastic tissue to the surgical capsule from a point 1.5 cm distal to the ureteral orifice. At the end of the operation, blood vessels are coagulated, and the bladder is drained with a urethral catheter for a day.

The advantage of this technique over others, where the dissection of the prostate is carried out on 4, 6 and 3, 8 and 9 hours of the conditioned dial, is to carry out an incision along the natural interstitial boundaries of the prostate, with less tissue trauma and the risk of bleeding. However, the final choice between dissection and resection is possible only with urethrocystoscopy. Which allows you to clearly define the size of the prostate and the shape of its growth.

[8], [9]

Prostate adenoma - surgery: methods of laser surgery

The history of the use of lasers in urology is more than 30 years old. The basis for the use of laser technologies in the treatment of prostate adenoma was the desire to improve the results of TUR by reducing the number of complications, primarily hemorrhagic. The energy of the laser is used for coagulation, dissection and evaporation of tissue. Up to 60-70% of laser energy is absorbed, and 30-40% is reflected by tissues. Absorption of laser radiation, caused by tissue effects and the depth of damage are due to the wavelength and power. The achieved thermal effect also depends on the type of tissues exposed to the effect, their combination and vascularization.

It should be borne in mind that high-power radiation, focused in a small volume, even with a relatively short application time, can quickly lead to carbonization of the tissue, which prevents further treatment. On the other hand, a lower energy density with a longer exposure time ensures deep coagulation.

Coagulation and evaporation refer to the basic techniques of laser surgery of prostate adenoma. Treatment can be carried out by contact and non-contact methods.

• Laser vaporization of the prostate.
  • Non-contact (Side-fire).
  • Contact.
• Laser coagulation of the prostate.
  • Non-contact (Side-fire).
  • Contact.
  • Interstitial.

A combined method is also applied, using these techniques simultaneously. Separately, the method of interstitial laser coagulation of the prostate is distinguished.

For remote (contactless) endoscopic laser coagulation, fiber optic fibers such as Urolase (Bard), Side-fire (Myriadlase), ADD (Laserscope), Prolase-II (Cytocare), Ablaster (Microva-sive) with special tips guiding the laser beam under angle to the longitudinal axis of the fiber. In this case, the angle of incidence in various designs is from 35 ° to 105 °. In foreign literature, the method is called visual (endoscopic) laser ablation of the prostate (VLAP or ELAP). The contactless technique differs from the contact by a smaller concentration of energy, since the removal of the fiber tip from the tissue surface increases the scattering of the laser beam and reduces the energy density.

Transurethral contact laser vaporization of the prostate under endoscopic control is carried out by direct contact of the fiber tip with tissue. At the same time, due to the creation of a large energy density at the point of contact, the fibers and the fabric reach a high temperature, leading to an evaporation effect. For contact vaporization, fibers with special sapphire tips or light guides with a lateral beam direction are used, the tip of which is protected by a special quartz cap: STL, Ultraline, Prolase-I.

The advantage of the method is the possibility of simultaneous removal of hyperplastic tissue under the control of vision. However, this procedure requires a lot of energy and is more time-consuming than a non-contact technique. So. Energy costs for an adenoma of 20-40 g are 32 to 59.5 kJ, and for masses of more than 40 g, they can reach 62-225 kJ with a duration of the procedure from 20 to 110 minutes. Usually, the power is 60-80W.

The frequency of intra- and postoperative bleeding, urinary incontinence, sexual disorders and urethral stricture during contact vaporization is significantly lower than with TUR. One of the most frequent complications of the method is a prolonged postoperative urinary retention, which occurs in 5-8% of patients.

Combined technology implies a combination of contact and non-contact techniques. The operation is divided into 2 stages. First, the prostate is dissected at 5, 7 and 12 hours of the conditioned dial by contact, and then the hyperplastic tissue is coagulated for 2, 6 and 10 hours, respectively. The method gives good results with a small number of complications.

Recently, there have been reports of a new endoscopic method of resection of prostate adenoma using a holmium laser. The technique of the operation differs significantly from that described above. The holmium laser provides the best evaporation effect with a smaller (up to 2 mm) coagulation depth, which allows it to be successfully used for tissue dissection. The method implies the resection of the middle and lateral lobes of the prostate along the periphery, followed by their dissection in the transverse direction and removal. This technique needs to be studied further.

The least invasive method of laser therapy for prostate adenoma is interstitial laser coagulation of the prostate, in which a light guide (5 CH) is injected directly into the prostate tissue by transurethral under endoscopic control or transperitoneally under ultrasound guidance. For this purpose, fiber optic fibers with pointed tips are used, which diffusely scatter laser radiation in the form of a sphere.

After insertion of the tip into the prostate tissue, it takes a long (3-10 min) heating to 66-100 ° C, induced by a laser at a low power level (5-20 W). The use of low energies is necessary to prevent the carbonization (charring) of the tissue, which reduces the penetration of laser radiation and can cause overheating and damage to the tip itself. Treatment is carried out under epidural or intravenous anesthesia. As a result of the action around the tip, a zone of coagulative necrosis with a diameter of up to 2.5-3 cm is formed. Depending on the size and configuration of the prostate, it becomes necessary to change the position of the fiber 2 to 10 times during the procedure. Which affects the total duration of the operation. The average operation time is 30 minutes. At the same time, the total dose of energy is from 2.4 to 48 kJ (average 8.678 kJ).

Treatment of patients reliably reduces the severity of the symptoms of the disease. Increases Qmax, decreases Vost, and the volume of the prostate gland decreases by 5-48%. After laser therapy, irritative symptoms and temporary postoperative urinary incontinence are observed less frequently than after TUR. Of the complications in the early postoperative period, irrational symptoms in 12.6%, bacteriuria in 35.6%, pain in 0.4%, secondary bleeding in 2.1% and stress urinary incontinence in 0.4% of patients.

Thus, the methods of laser surgical treatment of prostate adenoma are clinically effective and relatively safe. The main reason that limits their distribution. Economic: the cost of the necessary equipment for laser surgery is many times greater than that for standard electrosection or electropolarization of the prostate.

Transurethral microwave thermotherapy

Fundamentally, other processes are observed in the regime of thermotherapy (45-70 ° C) when the threshold for the temperature tolerance of prostate cells corresponding to 45 ° C is reached. The upper temperature limit of the thermotherapy regimen is currently not clearly defined. Different authors give values in the range 55-80 ° C. Thermotherapy is a minimally invasive method, based on the effect on the prostate tissue of unfocused electromagnetic energy. At the same time, energy is supplied to the prostate with a transurethral antenna. The thermal therapy session is usually one-time, lasting 60 minutes.

Transurethral access provides:

• the primary effect on the neck of the bladder and prostatic section of the urethra localization area of alpha-adrenergic receptors;
• the primary effect on the transitional zone of the prostate, where the main centers of proliferation of adenoma are concentrated;
• The best conditions for creating a channel of urine outflow (taking into account the small depth of penetration of microwaves).

The mechanism of action of transurethral microwave thermometry is the formation of a necrosis zone in the depth of the prostate tissue while maintaining the prostatic section of the urethra intact. In this regard, almost all devices of microwave thermotherapy are equipped with a cooling system. Consequence of temperature influence formation in the depth of the prostate of the focus of necrosis. Subsequent replacement of necrotic areas with a denser fibrous tissue leads to traction of the urethral wall to the periphery, which reduces the urethral resistance and IVO. In addition, thermal denaturation of the alpha-adrenergic receptors of the neck of the bladder, prostate and prostatic section of the urethra explains the effect of transurethral microwave thermometry on the dynamic component of obstruction by a stable alpha-adrenoblockade. The specific effect of microwaves on the prostate tissue leads to the formation of a zone of ultrastructural cellular changes around the focus of necrosis, in which an antiproliferative effect of thermotherapy appears. The effects characteristic of hyperthermia are observed at the periphery of the hot spot.

The principal point of planning a thermal therapy session in a specific clinical situation is the use of an optimal dose of absorbed energy. Which is determined by the ratio of output power and cooling mode of the urethra. It should be borne in mind that insufficient cooling can lead to an increase in the number of complications due to thermal trauma to the urethra, while too intense cooling leads to a decrease in the effectiveness of thermal exposure. The lower the temperature of the coolant, the lower the maximum temperature in the depth of the tissue and, correspondingly, at a greater distance from the urethra, there is a maximum temperature peak.

Comparison of urodynamic parameters after transurethral microwave thermometry and TUR shows that operative treatment has a significant advantage, but this thermal method has a comparable symptomatic effect. But, given the postoperative complications. It can be said that thermal treatment is much safer than electroresection.

The following adverse reactions were observed during thermotherapy: bladder spasm (in 70% of patients), minor hematuria (50-70%), dysuria (48%), pain in the urethra or perineum (43%). These symptoms did not require discontinuation of treatment and disappeared on their own after a while. In 8.14% of patients after thermotherapy, ejaculation disorders were noted.

The most frequent complication of thermal therapy was acute urinary retention, which was observed in almost all patients who underwent high-intensity exposure. The development of acute urinary retention requires drainage of the bladder with a urethral catheter or by trocar cystostomy.

Transurethral radiofrequency thermal destruction

The idea of a severe temperature effect with pronounced obstructive manifestations was realized in the method of transurethral radiofrequency thermal destruction (or thermoablation) of the prostate (70-82 ° C). This method is based on the use of the energy of electromagnetic oscillations of the long-wave radio range. In contrast to other types of electromagnetic energy, the penetration of radio emission is much less dependent on the properties of the medium. This makes it possible to use this method for prostate adenoma in combination with pronounced sclerotic changes and calcification of the prostate, i.e. When the application of other types of thermal treatment is limited.

Mounted on the basis of the urethral catheter, the antenna converts the energy of the high frequency electromagnetic field into thermal energy, which causes destruction of tissues as a result of local temperature increase to 80 ° C and higher. As a result of a single hour procedure around the prostatic section of the urethra in a radius of 10 mm or more, an extensive zone of coagulation necrosis occurs. After rejection of necrotic masses after 6-8 weeks, a cavity is formed in this region, which leads to the elimination of infravesical obstruction. Due to the fact that the method implies thermal destruction of the prostatic section of the urethra, the need for its cooling disappears. Only local cooling of the region of the seminal tubercle and the striated sphincter is produced. The computer security system does not allow the temperature in the area of the anterior wall of the rectum to rise above the critical level of 42 ° C. Considering the large volume of tissues that are subject to destruction, the method can be used in patients with severe infravesical obstruction and with cystostomic drainage to restore independent urination.

A comparison of the results of transurethral radiofrequency thermodestruction and TUR showed that this method can not compete with operative treatment, but in some cases they show comparable results.

The most common complication of transurethral radiofrequency thermodestruction with preserved independent urination is an acute delay in urination, which develops in almost all patients. Expressed destructive changes in the area of the prostatic urethra make objective difficulties in conducting the urethral catheter. Which requires emergency cystostomy. Considering the need for prolonged drainage of the bladder (up to 10 days or more), it is advisable to perform the procedure with puncture cystostomy.

Balloon dilatation

Balloon dilatation - a direction in the treatment of prostate adenoma, based on attempts at mechanical dilatation of the prostatic urethra, has a long history. The metal dilator was first used for this purpose by Mercier in 1844. Later, several different balloon systems for dilatation were proposed. There is also a combination of balloon dilatation of the prostatic section of the urethra with a simultaneous session of water hyperthermia. In this case, a liquid heated to 58-60 ° C is supplied under pressure to the cylinder.

Theoretically, the effect of balloon dilatation is a mechanical expansion of the urethra, commissurotomy (intersection of the anterior and posterior inter-lobar commissures). Compression of the prostate and the effect on the alpha-adrenoreceptors of the neck of the bladder and the prostatic department of the urethra.

Manipulation is performed under local anesthesia with an endourethral gel. The balloon catheter is placed under endoscopic or radiographic control. Expansion of the balloon is carried out at a pressure of 3-4 atm. Up to about 70-90 CH.

Clinical observations demonstrate a short-term positive dynamics of subjective and objective indicators in about 70% of patients. However, after a year, the effect remains only in 25% of patients. The most common complication of the method is macrohematuria. The results of subsequent randomized trials indicated unsatisfactory long-term balloon dilation results, and therefore the 3rd International Meeting on Prostate Hyperplasia did not recommend this method for widespread use.

[10], [11], [12], [13], [14], [15], [16]

Urethral stents

To the palliative methods of eliminating the infravesical obstruction in prostate adenoma is the setting of endourethral stents, the increase in interest to which is noted recently. The implantation of urethral stents can be used as an independent treatment for prostate adenoma or as the final stage of various treatment methods, when adequate long-term drainage of the bladder should be ensured. The main arguments in favor of the use of internal drainage systems are a reduction in the risk of urinary infection, a reduction in the length of hospitalization, and rapid social adaptation of the patient. The use of stents is contraindicated in the presence of recurrent urinary infection, stones and neoplasms of the bladder, neurogenic bladder, urinary incontinence and dementia.

For intra-urethral drainage of the bladder, several devices of different design have been proposed, which, by the time spent in the back of the urethra, can be divided into temporary and permanent ones. Temporary stents include intraurethral catheters, urological spirals of I and II generation, and also self-absorbing stents.

Intraurethral catheters Nissenkorn and Barnes are made of polyurethane. They have on the end a fixing socket (like the Maleko) and a thread for extraction. The cases of installation of a Nissenkorn catheter for up to 16 months are described.

The temporary stents of the first generation include Urospiral, Endospire and Prostacath. This type of stent is a tightly twisted steel spiral with a diameter of 20 to 30 CH. Which ends with a bridge and a fixing ring. They produce stents of several sizes, with Endospire and Prostacath having a gold coating. The main fragment of the spiral is placed in the prostatic. And the fixing ring - in the bulbar section of the urethra so. That the transitional bridge was in the area of the external sphincter of the bladder. The stents are placed under X-ray or ultrasound control using endoscopic instruments or special catheters.

Use of perspective materials, for example titanium-nickel alloys with the memory effect (nitinol). Led to the emergence of second-generation second generation Memokath and Prostacoil.

The advantage of stents with memory effect is their ability to change their sizes under the influence of different temperatures. The Memokath stent is a Urospiral with an external diameter of 22 SN and an internal 18 CH. Before injection, the stent is cooled and placed in the prostatic section of the urethra under visual control with a flexible cystoscope. When irrigation with a solution heated to 50 ° C, the stent expands and densely fixed to the wall of the urethra. If necessary, the urethra is irrigated with a cold solution (10 ° C), after which the stent can be easily moved to a new position or removed.

The Prostacoil helix is also made of nitinol and consists of two fragments connected by a bridge. Its diameter in the cooled state is 17 CH, while in the expanded form it reaches 24-30 CH. Stents of 40 to 80 mm in length are produced. The stent is placed in a cooled state with the help of a special catheter-conductor under X-ray or ultrasound control. A long fragment of the spiral is set in the prostatic, and a short one in the tabloid section of the urethra. The stent is extracted as described above.

Clinical results indicate a high effectiveness of temporary stents. According to various authors, symptomatic improvement is observed in 50-95% of patients.

After stent placement, the urodynamic parameters improve, and Qmax can increase 2-3 times. There is a significant decrease in V and decrease in detrusor pressure according to cystomanometry.

Complications of internal drainage with temporary stents:

• stent migration;
• urinary infection;
• incrustation of the stent;
• Irritative symptoms and stress urinary incontinence;
• urethrorrhagia.

Their frequency depends on the type of stent and the timing of drainage. More complications are noted when using stents of the first generation. Clinical experience with the use of Memokath and Prostacoil spirals testifies to the incidence of complications of 7-9%, and cases of stent migration and their incrustation were practically absent.

The production of bioresorbable stents is referred to as the latest biotechnology. And their clinical application is at the experimental stage. They are of the form of an ursopirali, they are made from polyglycolic acid polymers. Stents with different programmed resorption time from 3 to 25 weeks were developed and tested: PGA 3-4 weeks. PDLLA 2 months: PLLA - 4-6 months. They are planned to be used for internal drainage of the bladder after various endoscopic and thermal procedures (laser ablation, laser or radiofrequency interstitial coagulation of the prostate, transurethral thermotherapy, thermotherapy, focused ultrasound thermoablation, etc.). The first experience in the clinical use of self-resorbable stents indicates a good result with a minimal number of complications.

Permanent stents are designed for lifelong drainage of the bladder and look like an elastic mesh tube made of metal wire. They include: titanium stent ASI. Urolume Wallstent. Ultraflex and Memotherm. After the stent is installed, the mucous membrane of the urethra sprouts its mesh structure, followed by epithelization after 3-6 months. In this regard, after a long stand, remove the stent is almost impossible.

The ASI stent made from titanium is a collapsible structure with a diameter of 26 CH, which is placed on the balloon of the urethral catheter before administration. The stent is placed under X-ray or ultrasound. After inflation of the balloon in the area of the prostatic section of the urethra it spreads up to 33 CH, due to which it is firmly fixed to the urethral wall.

Stents Urolume and Uroflex have a similar device and a kind of spiraling metal mesh. Urolume produced in length from 15 to 40 mm and in straightened state has a diameter of 42 CH. Stents of this type are installed under endoscopic control with a special tube with an optical channel. Inside which the stent is in a compressed state. After choosing a position with a special pusher, the stent is moved to the urethra, where it is straightened and fixed due to its elastic properties. However, with an error in positioning, moving the stent to a new position is almost impossible, which requires its removal.

The Memotherm stent is also a mesh structure that. However, it has a different weaving from its previous devices, it is made of nitinol. Initially, it is installed with a similar tool as described above. If it is necessary to change the position of the stent, it is irrigated with a cold solution, after which it can be displaced or removed. It is possible to re-install the stent in the cooled state with the help of endoscopic forceps. After heating, the stent is straightened and fixed in this position to the urethral wall.

Thus, based on the analysis of existing methods of treating prostate adenoma, it can be said that at the present stage of urology development there is no ideal method. An impressive arsenal of tools used today, poses a difficult task for specialists to choose the method that best suits the specific clinical situation. The determination of indications for this or that kind of impact eventually leads to a balance between the efficacy and safety level of the treatment method in question. One of the determining factors is ensuring the necessary quality of life for the patient.