rus
DOI: 10.22184/1993-7296.FRos.2020.14.3.282.291
The article provides an overview of the applications of lasers in surgery, special attention is paid to the use of laser instruments in the field of coloproctology. The morphological data obtained in studies of the effect of laser radiation on biological tissues are presented. It is noted that the reparative reaction of various tissues in response to high-intensity laser exposure is of the same type and consists in their general regeneration with final healing by day 20–21.
The article provides an overview of the applications of lasers in surgery, special attention is paid to the use of laser instruments in the field of coloproctology. The morphological data obtained in studies of the effect of laser radiation on biological tissues are presented. It is noted that the reparative reaction of various tissues in response to high-intensity laser exposure is of the same type and consists in their general regeneration with final healing by day 20–21.
Теги: diode lasers hemorrhoids laser radiation surgery геморрой диодные лазеры лазерное излучение хирургия
Application of Lasers in Surgery
N. K. Zhizhin1, Yu. Yu. Kolbas2, Ev. V. Kuznetsov2
Foundation for the Support of Writers Central Polyclinics, CJSC, Moscow, Russia
Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia
The article provides an overview of the applications of lasers in surgery, special attention is paid to the use of laser instruments in the field of coloproctology. The morphological data obtained in studies of the effect of laser radiation on biological tissues are presented. It is noted that the reparative reaction of various tissues in response to high-intensity laser exposure is of the same type and consists in their general regeneration with final healing by day 20–21.
Key words: laser radiation, diode lasers, surgery, hemorrhoids
Received on: 24.02.2020
Accepted on: 22.04.2020
The results of the use of laser radiation in medicine have been known for a long time, since the invention of the laser [1, 2]. In urgent surgery, new types of lasers are actively used as an alternative to direct surgical methods. The characteristics of the output parameters of laser radiation and their correlation with the absorption of various chromophores of human biological tissues (Fig. 1) determine the possibility and mechanism of clinical application of various types of lasers. The basis of the effects that occur in biological tissues under the action of laser radiation is the thermophysical effect of radiation on absorbing tissues.
The emergence of each new type of laser instruments is associated with the development of new medical technologies. One of the first types of medical lasers was CO2 lasers. For medical applications use the generation of radiation at a wavelength of 10.6 microns. Water and organic compounds actively absorb this radiation. A variety of CO2 lasers operating in the continuous mode of generation of radiation or in the mode of generation of pulses, allows you to choose laser instruments for a wide range of medical applications. The radiation penetration depth for biological tissues of various types reaches up to 100 μm, the surface radiation exposure allows efficient tissue excision without negative thermal effects. This type of laser is used mainly in gynecology, otorhinolaryngology, cosmetology and general surgery [3] (Fig. 2).
The other most common type of medical lasers are garnet or neodymium (Nd) doped solid-state lasers. Among neodymium lasers, the Nd : YAG laser (operating radiation wavelength 1064 nm) is most in demand for medical purposes. The tool works both in continuous and in pulsed mode.
The pulse repetition rate varies up to hundreds of kilohertz, the pulse duration is less than one ps. Therefore, the power in the pulse can be hundreds of MW. A distinctive feature of Nd : YAG lasers is the availability of technical solutions for generating radiation at wavelengths of 532, 355, 266 and 213 nm. The main area of application of Nd : YAG lasers in medicine has become therapeutic. The technique of their application includes deep and volume coagulation, which provides high penetrating ability (up to 10 mm) of radiation into various biological tissues. The same property contributed to the widespread introduction of Nd : YAG lasers in dermatology and cosmetology [4]. However, it also limits the use of Nd : YAG lasers in surgery (except for ophthalmology), since the laser beam affects too large areas of tissue.
Excimer lasers with radiation in the UV range (λ = 157–351 nm) are used in ophthalmology (Fig. 4), where their use is aimed at the precision evaporation of the cornea [5] or therapeutic effect [6]. The variety of excimer lasers used is associated with the compositions of the active medium (gas mixture). The radiation wavelengths depend on the filling of the working medium of the laser: based on fluorine dimers or compounds of fluorine, bromine or chlorine with argon, krypton or xenon.
Semiconductor (diode) lasers have become extremely competitive in the field of medicine. Due to the variety of design solutions and the wide range of materials used in their production, many different types of diode lasers have appeared. They have a wide spectrum of wavelengths (λ = 0.5–5 μm) and a wide range of powers. The ability to work in continuous and pulsed modes (with a pulse repetition rate of up to several megahertz and a pulse duration of up to one μs) reveals the potential for use in various medical technologies. A distinctive feature of diode lasers is a high efficiency (efficiency up to 90%), miniature size, low price, the combination of up to four lasers with different wavelengths and with the possibility of their simultaneous operation in one housing, as well as a significant working life (up to 50,000 hours). The most widespread use of diode lasers in the field of dermatology and cosmetology. However, due to the variety of output parameters and affordable price, diode lasers are currently one of the most common types of lasers in medicine (Fig. 5).
Laser radiation is actively used in the surgical correction of hemorrhoids. High-intensity laser radiation has been successfully used in abdominal surgery for more than 40 years [7, 8]. In the subject literature, one can find reports on the use of different parameters of laser radiation for coagulation of hemorrhoids, cavernous and vascular formations of the anorectal region [6, 9, 10].
Early publications of the 80–90s of the last century were devoted to the open use of CO2 lasers during hemorrhoidectomy – for excision or vaporization of nodes [11–13]. For the same purpose, Nd-YAG lasers were used [14]. With the advent of portable and easy-to-use diode high-energy lasers in the 90s of the last century, the range of laser radiation wavelengths expanded significantly, the reliability of laser devices increased, and their cost decreased [15].
The mechanism of interaction of high-energy lasers has been well studied and is described in detail in numerous publications [16, 17]. The radiation of these lasers primarily causes a thermal effect due to the absorption of light quanta by the tissues with the transformation of light energy into thermal energy. As a result, an increase in exceptionally high temperature appears on an extremely small area. As a result, instantaneous evaporation of tissue fluid occurs with coagulation of cellular structures and the development of coagulation laser tissue necrosis. Pigment substances such as melanin, carotene, hemoglobin, myoglobin (see Fig. 1), selectively absorb radiation with a wavelength of the visible part of the spectrum (from 0.40 to 0.70 μm). Radiation in the violet and blue parts of the spectrum of electromagnetic waves has the smallest penetrating power, and the greatest in red.
Near-infrared radiation (wavelengths 0.70–1.40 microns) penetrating the tissue most deeply, is primarily absorbed by cellular proteins. It was clearly established that, for a wavelength of 0.81 μm, the target chromophore is oxyhemoglobin [18]. With the introduction of the fiber into the lumen of the vessel and exposure to radiation of a given wavelength, local boiling of blood occurs with the formation of gas bubbles, which damage the vessel wall with thermal energy, starting with intima. Damage to the layers of the venous wall creates the conditions for the formation of an occlusive fixed extended thrombosis with subsequent fibrous degeneration of the wall and the termination of blood flow through the vessel. Laser radiation in the range of 0.81–1.06 μm wavelengths is characterized by high absorption in hemoglobin and low absorption in water (although until recently it was widely used for laser phlebobliteration) [19]. The indicated wavelengths are referred to as «hemoglobin-absorbing» laser systems (H‑lasers). When using them, obliteration of small diameter veins occurs in 90–97% of cases [20].
In 2003, at the International Congress in San Diego, M. Goldman reported the use of 1.32 μm Nd : YAG lasers for phlebocoagulation, the radiation of which is already noticeably absorbed not only in oxyhemoglobin, but also in water. Absorption of radiation of this wavelength in oxyhemoglobin still predominates over absorption in water [21]; therefore, assigning this radiation to «water-absorbing» or «water-specific» is not entirely correct [10, 22]. It is more correct to use this term for lasers with wavelengths closer to 1.5 μm, in which absorption in water will be predominant. Such lasers with a wavelength of 1.47–1.5–1.56 μm (denoted as W‑lasers) are actively used for phlebobliteration [23]. Radiation with a wavelength of 10.6 microns is almost completely absorbed by water molecules, slightly scattering in the tissues.
This means an almost complete absorption of this radiation in the upper layers of the tissues of the irradiated object. Features of the action of laser radiation on tissue is also determined by the density of its power, the degree of focusing of the beam and depends on the physicochemical and biological characteristics of the irradiated tissues [8, 14].
The thermal effect of a high-energy laser is the main mechanism for the interaction of radiation with tissues. The temperature reaction of tissues depends on the power of laser radiation, its wavelength, beam diameter, exposure time, as well as the content of water and pigment in the irradiated tissues. The weakest and partially reversible reaction is protein denaturation, which occurs when tissues are heated to a temperature of 40–53 °C. In this case, there is a violation of procollagen and fibrin protein bonds with denaturation and melting of collagen. Nevertheless, the bonds of the collagen chains of protein molecules are preserved and, when the laser exposure ceases, they are restored again, although with some rearrangement of the matrix. An increase in temperature in tissues under conditions of exposure to laser radiation of more than 53 °C leads to irreversible damage. The manifestation of the effect of laser photodestruction begins at a temperature of 55 °C in the irradiated tissues. The initial phase of tissue destruction (protein degradation) develops at a temperature of 63 °C. At the same time, all structures of the collagen matrix undergo collapse and degradation (pyknotic changes in the nuclei are morphologically revealed in the cells). After the termination of the laser exposure, complete restoration of the cells and the reverse development of damage does not occur. Coagulation processes develop in tissues under the influence of laser radiation at a temperature of 63 °C, which, along with denaturation and dehydration of proteins, is accompanied by their contraction with compaction and a decrease in the volume of the main substance. Histologically, this is characterized by basophilic and pyknotic changes in cells with the presence of a network-like substance that occurs in the process of blood coagulation [21, 23].
An increase in temperature in tissues exposed to high-intensity laser radiation of more than 90 °C leads to the effect of tissue evaporation. Tissue fluid begins to boil with the formation of small vesicle vacuoles detected by histological examination. With laser exposure, which provokes an increase in temperature in tissues up to 100 °C, the liquid boils instantly with the formation of steam, rupture and destruction of cells. Morphologically, coagulation necrosis and protein denaturation with the presence of edema, vascular disorders, and hemorrhages in the surrounding tissues are detected in the affected area.
With an increase in temperature in tissues caused by laser exposure, from 500 °C or more, carbonization of tissues occurs with carbonization and complete destruction of the morphological structure. The morphology and morphometry of wounds arising from the action of high-intensity lasers on various tissues has been studied quite well [3, 19] and has a number of common features, significantly differing from the histological picture of wounds of other origin. Directly in the zone of laser exposure, coagulation necrosis of tissues is observed with the formation of a characteristic scab in the future. On the border with necrosis, edema, circulatory disorders in the form of hyperemia, stasis, diapedetic hemorrhages are determined. Typically, the area of thermal damage is sterile and minimal, not more than 0.15 mm. Coagulation of blood and lymph in the lumen of small vessels, with a diameter of 0.3–0.5 mm, provides hemo- and lymphostasis, which eliminates the possibility of bleeding from the wound and the development of congestive edema of the surrounding tissues.
Morphologically, the following zones of laser exposure to tissues are distinguished: a zone of coagulation necrosis in the form of a burn border; the zone of loose and compact layers of necrosis and the zone of inflammatory edema. The width of these zones depends on the type of laser and the wavelength of the beam it generates, as well as on the type of tissue. An important property of high-intensity laser radiation is a powerful bactericidal effect, the manifestation of which eliminates septic inflammation in the tissues of the affected area, usually referred to as «laser wounds». Weak exudation from the microvasculature of laser wounds, the absence of the release of kinins and other vasoactive substances from coagulated tissues leads to a weak leukocyte infiltration of them [14, 16]. Aseptic inflammation and the absence of edema in such tissues cause the early proliferation of macrophages, fibroblasts, which in turn contributes to the activation of the immune system and the synthesis of collagen and chalones responsible for tissue regeneration. The rapid accumulation in the tissues of glycosaminoglycans, which are the main substance of the connective tissue, mild exudation, the absence of leukocyte infiltration with a predominant reaction of macrophages and fibroblasts, promotes the healing of laser wounds by primary intention without rough scar formation. It should be noted that the reparative reaction of various tissues in response to a high-intensity laser exposure is of the same type [8, 10, 11] and consists in their general regeneration with final healing by 20–21 days.
The use of diode lasers in surgery allows for less traumatic, with minimal pain syndrome, optimization of surgical tactics in the treatment of anorectal diseases. Cytomorphological criteria when exposed to laser radiation on body tissues characterize it as nonbacterial and having a fast healing spectrum, without gross scarring.
There is no doubt that the use of lasers in medicine is promising, but require further study of the interaction of laser radiation with biological tissues. To use laser instruments in wide surgical practice, it is necessary to develop clinical methods for using diode lasers. In the treatment of general proctologic diseases of the anorectal zone, it is necessary to carry out the processes of morphological verification of the wound process of the tissues of the rectum and anal canal in order to optimize drug treatment.
Furthermore, it is important not to forget about the technical problems of introducing radiation from a diode laser into a fiber. Not all radiation coming out of the laser diode enters the leading mode, a part of the radiation flies past the fiber, and a part falls into the shell and then flows out. It is important to introduce modern technologies for introducing radiation into the optical fiber to ensure an effective therapeutic effect.
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ABOUT AUTHORS
N. K. Zhizhin, Cand. of Scien (Med.), gigin2000@mail.ru, ZAO Central’naya poliklinika Litfonda, Moscow, Russia.
ORCID:0000-0002-7825-3556
Yu. Yu. Kolbas, Dr. of Scien. (Eng.), tigra-e@rambler.ru, Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia.
ORCID:0000-0002-6867-0065
Ev. V. Kuznetsov, Dr. of Scien. (Eng.), Prof., bereg@niipolyus.ru, Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia.
N. K. Zhizhin1, Yu. Yu. Kolbas2, Ev. V. Kuznetsov2
Foundation for the Support of Writers Central Polyclinics, CJSC, Moscow, Russia
Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia
The article provides an overview of the applications of lasers in surgery, special attention is paid to the use of laser instruments in the field of coloproctology. The morphological data obtained in studies of the effect of laser radiation on biological tissues are presented. It is noted that the reparative reaction of various tissues in response to high-intensity laser exposure is of the same type and consists in their general regeneration with final healing by day 20–21.
Key words: laser radiation, diode lasers, surgery, hemorrhoids
Received on: 24.02.2020
Accepted on: 22.04.2020
The results of the use of laser radiation in medicine have been known for a long time, since the invention of the laser [1, 2]. In urgent surgery, new types of lasers are actively used as an alternative to direct surgical methods. The characteristics of the output parameters of laser radiation and their correlation with the absorption of various chromophores of human biological tissues (Fig. 1) determine the possibility and mechanism of clinical application of various types of lasers. The basis of the effects that occur in biological tissues under the action of laser radiation is the thermophysical effect of radiation on absorbing tissues.
The emergence of each new type of laser instruments is associated with the development of new medical technologies. One of the first types of medical lasers was CO2 lasers. For medical applications use the generation of radiation at a wavelength of 10.6 microns. Water and organic compounds actively absorb this radiation. A variety of CO2 lasers operating in the continuous mode of generation of radiation or in the mode of generation of pulses, allows you to choose laser instruments for a wide range of medical applications. The radiation penetration depth for biological tissues of various types reaches up to 100 μm, the surface radiation exposure allows efficient tissue excision without negative thermal effects. This type of laser is used mainly in gynecology, otorhinolaryngology, cosmetology and general surgery [3] (Fig. 2).
The other most common type of medical lasers are garnet or neodymium (Nd) doped solid-state lasers. Among neodymium lasers, the Nd : YAG laser (operating radiation wavelength 1064 nm) is most in demand for medical purposes. The tool works both in continuous and in pulsed mode.
The pulse repetition rate varies up to hundreds of kilohertz, the pulse duration is less than one ps. Therefore, the power in the pulse can be hundreds of MW. A distinctive feature of Nd : YAG lasers is the availability of technical solutions for generating radiation at wavelengths of 532, 355, 266 and 213 nm. The main area of application of Nd : YAG lasers in medicine has become therapeutic. The technique of their application includes deep and volume coagulation, which provides high penetrating ability (up to 10 mm) of radiation into various biological tissues. The same property contributed to the widespread introduction of Nd : YAG lasers in dermatology and cosmetology [4]. However, it also limits the use of Nd : YAG lasers in surgery (except for ophthalmology), since the laser beam affects too large areas of tissue.
Excimer lasers with radiation in the UV range (λ = 157–351 nm) are used in ophthalmology (Fig. 4), where their use is aimed at the precision evaporation of the cornea [5] or therapeutic effect [6]. The variety of excimer lasers used is associated with the compositions of the active medium (gas mixture). The radiation wavelengths depend on the filling of the working medium of the laser: based on fluorine dimers or compounds of fluorine, bromine or chlorine with argon, krypton or xenon.
Semiconductor (diode) lasers have become extremely competitive in the field of medicine. Due to the variety of design solutions and the wide range of materials used in their production, many different types of diode lasers have appeared. They have a wide spectrum of wavelengths (λ = 0.5–5 μm) and a wide range of powers. The ability to work in continuous and pulsed modes (with a pulse repetition rate of up to several megahertz and a pulse duration of up to one μs) reveals the potential for use in various medical technologies. A distinctive feature of diode lasers is a high efficiency (efficiency up to 90%), miniature size, low price, the combination of up to four lasers with different wavelengths and with the possibility of their simultaneous operation in one housing, as well as a significant working life (up to 50,000 hours). The most widespread use of diode lasers in the field of dermatology and cosmetology. However, due to the variety of output parameters and affordable price, diode lasers are currently one of the most common types of lasers in medicine (Fig. 5).
Laser radiation is actively used in the surgical correction of hemorrhoids. High-intensity laser radiation has been successfully used in abdominal surgery for more than 40 years [7, 8]. In the subject literature, one can find reports on the use of different parameters of laser radiation for coagulation of hemorrhoids, cavernous and vascular formations of the anorectal region [6, 9, 10].
Early publications of the 80–90s of the last century were devoted to the open use of CO2 lasers during hemorrhoidectomy – for excision or vaporization of nodes [11–13]. For the same purpose, Nd-YAG lasers were used [14]. With the advent of portable and easy-to-use diode high-energy lasers in the 90s of the last century, the range of laser radiation wavelengths expanded significantly, the reliability of laser devices increased, and their cost decreased [15].
The mechanism of interaction of high-energy lasers has been well studied and is described in detail in numerous publications [16, 17]. The radiation of these lasers primarily causes a thermal effect due to the absorption of light quanta by the tissues with the transformation of light energy into thermal energy. As a result, an increase in exceptionally high temperature appears on an extremely small area. As a result, instantaneous evaporation of tissue fluid occurs with coagulation of cellular structures and the development of coagulation laser tissue necrosis. Pigment substances such as melanin, carotene, hemoglobin, myoglobin (see Fig. 1), selectively absorb radiation with a wavelength of the visible part of the spectrum (from 0.40 to 0.70 μm). Radiation in the violet and blue parts of the spectrum of electromagnetic waves has the smallest penetrating power, and the greatest in red.
Near-infrared radiation (wavelengths 0.70–1.40 microns) penetrating the tissue most deeply, is primarily absorbed by cellular proteins. It was clearly established that, for a wavelength of 0.81 μm, the target chromophore is oxyhemoglobin [18]. With the introduction of the fiber into the lumen of the vessel and exposure to radiation of a given wavelength, local boiling of blood occurs with the formation of gas bubbles, which damage the vessel wall with thermal energy, starting with intima. Damage to the layers of the venous wall creates the conditions for the formation of an occlusive fixed extended thrombosis with subsequent fibrous degeneration of the wall and the termination of blood flow through the vessel. Laser radiation in the range of 0.81–1.06 μm wavelengths is characterized by high absorption in hemoglobin and low absorption in water (although until recently it was widely used for laser phlebobliteration) [19]. The indicated wavelengths are referred to as «hemoglobin-absorbing» laser systems (H‑lasers). When using them, obliteration of small diameter veins occurs in 90–97% of cases [20].
In 2003, at the International Congress in San Diego, M. Goldman reported the use of 1.32 μm Nd : YAG lasers for phlebocoagulation, the radiation of which is already noticeably absorbed not only in oxyhemoglobin, but also in water. Absorption of radiation of this wavelength in oxyhemoglobin still predominates over absorption in water [21]; therefore, assigning this radiation to «water-absorbing» or «water-specific» is not entirely correct [10, 22]. It is more correct to use this term for lasers with wavelengths closer to 1.5 μm, in which absorption in water will be predominant. Such lasers with a wavelength of 1.47–1.5–1.56 μm (denoted as W‑lasers) are actively used for phlebobliteration [23]. Radiation with a wavelength of 10.6 microns is almost completely absorbed by water molecules, slightly scattering in the tissues.
This means an almost complete absorption of this radiation in the upper layers of the tissues of the irradiated object. Features of the action of laser radiation on tissue is also determined by the density of its power, the degree of focusing of the beam and depends on the physicochemical and biological characteristics of the irradiated tissues [8, 14].
The thermal effect of a high-energy laser is the main mechanism for the interaction of radiation with tissues. The temperature reaction of tissues depends on the power of laser radiation, its wavelength, beam diameter, exposure time, as well as the content of water and pigment in the irradiated tissues. The weakest and partially reversible reaction is protein denaturation, which occurs when tissues are heated to a temperature of 40–53 °C. In this case, there is a violation of procollagen and fibrin protein bonds with denaturation and melting of collagen. Nevertheless, the bonds of the collagen chains of protein molecules are preserved and, when the laser exposure ceases, they are restored again, although with some rearrangement of the matrix. An increase in temperature in tissues under conditions of exposure to laser radiation of more than 53 °C leads to irreversible damage. The manifestation of the effect of laser photodestruction begins at a temperature of 55 °C in the irradiated tissues. The initial phase of tissue destruction (protein degradation) develops at a temperature of 63 °C. At the same time, all structures of the collagen matrix undergo collapse and degradation (pyknotic changes in the nuclei are morphologically revealed in the cells). After the termination of the laser exposure, complete restoration of the cells and the reverse development of damage does not occur. Coagulation processes develop in tissues under the influence of laser radiation at a temperature of 63 °C, which, along with denaturation and dehydration of proteins, is accompanied by their contraction with compaction and a decrease in the volume of the main substance. Histologically, this is characterized by basophilic and pyknotic changes in cells with the presence of a network-like substance that occurs in the process of blood coagulation [21, 23].
An increase in temperature in tissues exposed to high-intensity laser radiation of more than 90 °C leads to the effect of tissue evaporation. Tissue fluid begins to boil with the formation of small vesicle vacuoles detected by histological examination. With laser exposure, which provokes an increase in temperature in tissues up to 100 °C, the liquid boils instantly with the formation of steam, rupture and destruction of cells. Morphologically, coagulation necrosis and protein denaturation with the presence of edema, vascular disorders, and hemorrhages in the surrounding tissues are detected in the affected area.
With an increase in temperature in tissues caused by laser exposure, from 500 °C or more, carbonization of tissues occurs with carbonization and complete destruction of the morphological structure. The morphology and morphometry of wounds arising from the action of high-intensity lasers on various tissues has been studied quite well [3, 19] and has a number of common features, significantly differing from the histological picture of wounds of other origin. Directly in the zone of laser exposure, coagulation necrosis of tissues is observed with the formation of a characteristic scab in the future. On the border with necrosis, edema, circulatory disorders in the form of hyperemia, stasis, diapedetic hemorrhages are determined. Typically, the area of thermal damage is sterile and minimal, not more than 0.15 mm. Coagulation of blood and lymph in the lumen of small vessels, with a diameter of 0.3–0.5 mm, provides hemo- and lymphostasis, which eliminates the possibility of bleeding from the wound and the development of congestive edema of the surrounding tissues.
Morphologically, the following zones of laser exposure to tissues are distinguished: a zone of coagulation necrosis in the form of a burn border; the zone of loose and compact layers of necrosis and the zone of inflammatory edema. The width of these zones depends on the type of laser and the wavelength of the beam it generates, as well as on the type of tissue. An important property of high-intensity laser radiation is a powerful bactericidal effect, the manifestation of which eliminates septic inflammation in the tissues of the affected area, usually referred to as «laser wounds». Weak exudation from the microvasculature of laser wounds, the absence of the release of kinins and other vasoactive substances from coagulated tissues leads to a weak leukocyte infiltration of them [14, 16]. Aseptic inflammation and the absence of edema in such tissues cause the early proliferation of macrophages, fibroblasts, which in turn contributes to the activation of the immune system and the synthesis of collagen and chalones responsible for tissue regeneration. The rapid accumulation in the tissues of glycosaminoglycans, which are the main substance of the connective tissue, mild exudation, the absence of leukocyte infiltration with a predominant reaction of macrophages and fibroblasts, promotes the healing of laser wounds by primary intention without rough scar formation. It should be noted that the reparative reaction of various tissues in response to a high-intensity laser exposure is of the same type [8, 10, 11] and consists in their general regeneration with final healing by 20–21 days.
The use of diode lasers in surgery allows for less traumatic, with minimal pain syndrome, optimization of surgical tactics in the treatment of anorectal diseases. Cytomorphological criteria when exposed to laser radiation on body tissues characterize it as nonbacterial and having a fast healing spectrum, without gross scarring.
There is no doubt that the use of lasers in medicine is promising, but require further study of the interaction of laser radiation with biological tissues. To use laser instruments in wide surgical practice, it is necessary to develop clinical methods for using diode lasers. In the treatment of general proctologic diseases of the anorectal zone, it is necessary to carry out the processes of morphological verification of the wound process of the tissues of the rectum and anal canal in order to optimize drug treatment.
Furthermore, it is important not to forget about the technical problems of introducing radiation from a diode laser into a fiber. Not all radiation coming out of the laser diode enters the leading mode, a part of the radiation flies past the fiber, and a part falls into the shell and then flows out. It is important to introduce modern technologies for introducing radiation into the optical fiber to ensure an effective therapeutic effect.
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ABOUT AUTHORS
N. K. Zhizhin, Cand. of Scien (Med.), gigin2000@mail.ru, ZAO Central’naya poliklinika Litfonda, Moscow, Russia.
ORCID:0000-0002-7825-3556
Yu. Yu. Kolbas, Dr. of Scien. (Eng.), tigra-e@rambler.ru, Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia.
ORCID:0000-0002-6867-0065
Ev. V. Kuznetsov, Dr. of Scien. (Eng.), Prof., bereg@niipolyus.ru, Research and Development Institute «Polyus» named after M. F. Stelmakh, Moscow, Russia.
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