rus
Issue #8/2021
N. K. Zhizhin, D. A. Ivanov, M. A. Ivanov, Y. Y. Kolbas, E. V. Kuznetsov, N. A. Kuzina, E. A. Shibeko
Optimization of Laser Radiation Parameters in the Surgical Treatment of Patients with Anorectal Pathology
Optimization of Laser Radiation Parameters in the Surgical Treatment of Patients with Anorectal Pathology
DOI: 10.22184/1993-7296.FRos.2021.15.8.676.686
The article presents a method for optimizing the parameters of laser radiation and a description of the developed computer program for patients with pathology of the anorectal area, as well as determines the criteria for choosing the levels of laser exposure. The practical results of the treatment of patients showed that the use of the developed method allowed reducing the level of exposure to laser radiation in 58% of patients. At the same time, 16 percent of patients had the exposure time increased, which resulted in carrying out a single surgery.
The article presents a method for optimizing the parameters of laser radiation and a description of the developed computer program for patients with pathology of the anorectal area, as well as determines the criteria for choosing the levels of laser exposure. The practical results of the treatment of patients showed that the use of the developed method allowed reducing the level of exposure to laser radiation in 58% of patients. At the same time, 16 percent of patients had the exposure time increased, which resulted in carrying out a single surgery.
Теги: diode laser hemorrhoids laser radiation software surgery tissue temperature геморрой диодный лазер лазерное излучение программное обеспечение температура ткани хирургия
Optimization of Laser Radiation Parameters in the Surgical Treatment of Patients with Anorectal Pathology
N. K. Zhizhin, D. A. Ivanov, M. A. Ivanov, Y. Y. Kolbas, E. V. Kuznetsov, N. A. Kuzina, E. A. Shibeko
Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow Federal Medical Center of the Federal Property Management Agency, Moscow
The article presents a method for optimizing the parameters of laser radiation and a description of the developed computer program for patients with pathology of the anorectal area, as well as determines the criteria for choosing the levels of laser exposure. The practical results of the treatment of patients showed that the use of the developed method allowed reducing the level of exposure to laser radiation in 58% of patients. At the same time, 16 percent of patients had the exposure time increased, which resulted in carrying out a single surgery.
Keywords: laser radiation, tissue temperature, software, diode laser, hemorrhoids, surgery
The article was received: 22.10.2021
The article was accepted: 17.11.2021
Laser technologies are extensively introduced into modern surgery. Semiconductor (diode) lasers are currently extremely competitive in the field of medicine. Due to the variety of design solutions and a wide list of materials used in the production, there are many different types of diode lasers with a wide range of possible powers and wavelengths (0.5–5 microns). A distinctive feature of diode lasers is their high efficiency, miniaturization, low price, and significant life cycle (up to 50,000 hours). The diode lasers are most commonly used in surgery. However, due to the variety of output parameters and affordable price, diode lasers are currently one of the most common types of lasers in coloproctology.
In the last decade, laser radiation has been actively used in the surgical correction of hemorrhoids. High-intensity laser radiation has been successfully used in abdominal surgery for more than 40 years [1–4]. In the issue-related literature, one can find reports on the use of various laser radiation parameters for coagulation of hemorrhoidal tumors, cavernous and vascular formations of the anorectal area. [2, 5] Miscellaneous information about the use of lasers in the treatment of anal fissures, rectal fistulas, condylomata, rectal polyps does not allow determining the algorithm of surgical treatment. The implementation of various laser surgical approaches in the pathology of the anorectal area has been developed, but there are no clear guidelines as to the mode of operation, beam power, and exposure time. The anthropometric data of patients are not taken into account at all.
Therefore, the aim of the work was to develop a program to optimize the use of laser radiation in the treatment of diseases of the anorectal area. To achieve the goal, the research team was assigned the following research objectives:
Materials and techniques
Research data on a sample of 362 patients treated with a diode laser within 3 years (2018–2020) were used to create a computer program. All patients had pathologies of the anorectal area. Surgical treatment of all patients was performed using a diode laser. The creation of the program involved the use of databases that contained anthropometric data of patients – height and weight, technical parameters of laser radiation – wavelength, beam power, and exposure time.
When utilizing the device in test run mode, a laser tool proves to be convenient for application: the device is easy to use (PLUG & PLAY technology is used, which simplifies the detection of a hardware component in the system without the need for user intervention), compact, convenient for transportation and use in various medical facilities during the working day. The interface placed on the touch screen uses the Russian language, as well as makes it possible to quickly use several operating modes when performing surgical interventions, sometimes even in one patient. Straight and radial light guides were used for all surgical interventions, with the 1.46‑micron radiation wavelength applied.
Hemorrhoidal disease was chosen as a biological model when writing the program. Straight light guides were used to treat hemorrhoids that resulted in the response of “white denaturation” of tissues. Sometimes the wounds were additionally stitched with a 3–0 Vicryl suture by means of a round needle for the purpose of additional hemostasis and mucosa lifting. When using radial light guides, the light guide was inserted percutaneously into the submucosal layer, and coagulation of hemorrhoids was carried out fanwise. The operation was carried out using a laser beam power of up to 8 W, with no response of “white denaturation” of tissues observed. Mucosal prolapse was lifted with a 3–0 Vicryl suture by means of a round needle. During the postoperative period, the pain syndrome was minimal and subsided on the 2nd day after the surgery, and the average period of disability was 10–12 days. The analysis of the pain syndrome was carried out using the Numeric Pain Rating Scale (NPRS).
The pain syndrome was 3–4 points when using straight light guides, 1–2 points when using radial light guides, by the 3rd day no pain syndrome was observed. All patients underwent epidural anesthesia (362 cases). This type of anesthesia involves the introduction of an anesthetic in the immediate vicinity of the spinal cord. Therefore, they are united by the concept of “central anesthesia”. In order to prevent the development of arterial hypotension, patients are subjected to volemic (infusion) load with solutions of crystalloids or solutions of colloids if necessary. This leads to an increase in preload and, consequently, to an increase in venous return and normalization of cardiac output. Dynamic monitoring of blood pressure, pulse, respiratory rate, and pulse oximetry is carried out during the initial examination of the patient, during preparation and anesthesia, as well as during the postoperative period.
It is implicit that devices that can be used for such treatment have also been proposed previously. For example, similar equipment using mechanical compression, ultrasound diagnostics, and ultrasound coagulation is proposed by Jimin Zhang et al [6].
The main difference between the use of laser radiation and ultrasonic heating or non-monochromatic photocoagulation is that it is capable of providing a selective effect on tissues with the right choice of radiation wavelength. This means that the use of laser radiation to solve the problem of blood coagulation in a vessel results in relatively low heating of the surrounding tissues [3].
For efficient coagulation of blood, radiation should be absorbed by hemoglobin to good effect, while the absorption of radiation by the tissues surrounding the vessel should be less so that the principle of selection is in place. To solve the problem of laser coagulation, it is also advisable to use a pulse-periodic mode of exposure, which will increase the efficiency of blood coagulation and ensure the safety of surrounding tissues due to a smaller heating zone.
It is also important to note the minimally invasive and convenient ways of delivering laser radiation to the affected area. Laser radiation is delivered to the area of exposure in the tissue thickness via a flexible optical fiber of small diameter using lenses, and the coagulation process itself can be carried out using endovasal laser obliteration and through the tissue [3, 5, 7–10].
Laser radiation has a number of other advantages: the area of thermal damage is kept sterile and does not exceed 0.15 mm. Coagulation of blood and lymph in the lumen of small vessels with a diameter of 0.3–0.5 mm provides hemostasis and lymphostases, which completely eliminates bleeding from the wound and the development of congestive edema of surrounding tissues [11,12].
Description of the laser equipment
To perform the research, the laser equipment is used (Fig.1) based on the ACT DUAL diode medical laser manufactured by Yurikon-Group LLC with radiation output through a radial optical fiber with a lens [12].
Radiation with a wavelength of 1470 nm is used. The power and duration of exposure varies widely – power up to 16 W, duration of exposure in one pulse up to 1000 ms. The total exposure time can be set by anyone, since any number of repetitive pulses is set.
Program Description
The developed program is equipped with an intuitive interface (Fig. 2). To calculate a personalized mathematical model, several input parameters (wavelength, exposure temperature, patient’s skin type, laser beam diameter, and power) should be entered. It is also necessary to enter the patient’s data, namely: full name, gender, and age. After calculations are made, the interface allows the surgeon to see how the temperature of the tissue will change when the laser is exposed to the biological tissue at different times and different depths from the surface and along the beam section.
The calculated parameters and patient data are recorded in the program database (Fig. 3), which can be used to collect anonymous statistics for the purpose of further development of the program and procedure.
The following algorithm is used to calculate the mathematical model:
1. The temperature variation of the cylinder in question that is under the influence of the laser in the horizontal and vertical directions should be calculated as follows:
, (1)
where C is the heat capacity of the biological tissue, mi is the mass of the cylinder in question at the integration step, Qi is the amount of heat transferred, i is the step number.
2. The amount of heat transferred between the layers due to diffusion should be calculated as follows:
, (2)
where S is the cross-section area, di is the cross-section diameter at the step, is the coefficient of thermal conductivity, dt is the time step of the integration;
2. Calculations, as specified in clauses 1 and 2, should be recursively performed until the calculated temperature of the layer with a given depth (Formula 3) is equal to the set temperature.
. (3)
The constants used by the program (reflection coefficients, heat capacity and thermal conductivity of biological tissue) necessary for calculation are made available in Table 2.
Discussion of the Results Obtained
The results of the developed algorithm employed and the program applied are presented below. A total of 362 patients were treated, the distribution of which by gender, age, and diagnosis of the disease is shown in Figures 4–6.
Without using a calculation program, the treatment algorithm provided for setting the output power of the diode laser at 10 W and varying the exposure time in the range of 800–3200 ms, depending on the diameter of the treated area as a subjective choice of the surgeon. On the one hand, this caused excessive tissue damage, on the other hand, repeated treatment was required in certain cases.
The use of the calculation program eliminated this downside. Consequently, the choice of parameters of the impacting laser radiation became personalized. As can be seen from the diagram in Fig.7, for 41.45% of patients, the laser radiation power was reduced by 20%, and for 29.57%, the power had to be reduced even by 30%.
The diagram in Fig.8 shows that the exposure time had to be significantly increased up to 12,000 ms for almost 16% of patients. But the surgery was completed in 1 cycle without having to apply the exposure repeatedly.
Conclusion
Consideration of the anthropometric parameters facilitates optimizing the radiation power, which further improves the morphometric parameters of the wound process, as well as reduces the wound healing period.
All these data were taken into account when writing the computer program, the following parameters were entered – the patient’s height, weight, exposure time in seconds, wavelength, radiation power in watts. All these data were further processed and laser exposure was personalized using mathematical modeling methods.
The developed software can be used to personalize the laser effect on the tissues individually for each patient. The biological model – hemorrhoids – requires further development of cytological and histological parameters, with individual data to be taken into account.
The development of software improvement based on the created model, taking into account the risk measuring parameters, will expand the potential of the application of diode lasers in coloproctology. And this method of laser surgery will be widely used by doctors.
ABOUT AUTHORS
Nikita Kirillovich Zhizhin. Senior Researcher, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of surgical treatment procedure.
ORCID: 0000-0002-7825-3556
Dmitry Alekseyevich Ivanov. Principal Software Engineer, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of user programs, databases.
ORCID: 0000-0001-9381-0747
Maxim Alekseyevich Ivanov. Head of the Laboratory, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of a software algorithm for the implementation of a mathematical model.
ORCID: 0000-0003-2738-0990
Yuriy Yuriyevich Kolbas. Deputy Head of Research and Manufacturing Complex‑470,
Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of a mathematical model.
ORCID: 0000-0002-6867-0065
Yevgeny Viktorovich Kuznetsov. General Director, Doctor of Engineering Science, Professor. Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of calculation procedure
ORCID: 0000-0002-3530-478x
Nadezhda Alekseyevna Kuzina. Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of a patient database.
ORCID: 0000-0001-5594-1260
Yelena Anatolyevna Shibeko. Head of the Therapeutic Department Federal Medical Center of the Federal Property Management Agency.
Completed tasks: Development of post-surgery treatment procedure and collection of patient data.
ORCID: 0000-0001-6356-0089
N. K. Zhizhin, D. A. Ivanov, M. A. Ivanov, Y. Y. Kolbas, E. V. Kuznetsov, N. A. Kuzina, E. A. Shibeko
Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow Federal Medical Center of the Federal Property Management Agency, Moscow
The article presents a method for optimizing the parameters of laser radiation and a description of the developed computer program for patients with pathology of the anorectal area, as well as determines the criteria for choosing the levels of laser exposure. The practical results of the treatment of patients showed that the use of the developed method allowed reducing the level of exposure to laser radiation in 58% of patients. At the same time, 16 percent of patients had the exposure time increased, which resulted in carrying out a single surgery.
Keywords: laser radiation, tissue temperature, software, diode laser, hemorrhoids, surgery
The article was received: 22.10.2021
The article was accepted: 17.11.2021
Laser technologies are extensively introduced into modern surgery. Semiconductor (diode) lasers are currently extremely competitive in the field of medicine. Due to the variety of design solutions and a wide list of materials used in the production, there are many different types of diode lasers with a wide range of possible powers and wavelengths (0.5–5 microns). A distinctive feature of diode lasers is their high efficiency, miniaturization, low price, and significant life cycle (up to 50,000 hours). The diode lasers are most commonly used in surgery. However, due to the variety of output parameters and affordable price, diode lasers are currently one of the most common types of lasers in coloproctology.
In the last decade, laser radiation has been actively used in the surgical correction of hemorrhoids. High-intensity laser radiation has been successfully used in abdominal surgery for more than 40 years [1–4]. In the issue-related literature, one can find reports on the use of various laser radiation parameters for coagulation of hemorrhoidal tumors, cavernous and vascular formations of the anorectal area. [2, 5] Miscellaneous information about the use of lasers in the treatment of anal fissures, rectal fistulas, condylomata, rectal polyps does not allow determining the algorithm of surgical treatment. The implementation of various laser surgical approaches in the pathology of the anorectal area has been developed, but there are no clear guidelines as to the mode of operation, beam power, and exposure time. The anthropometric data of patients are not taken into account at all.
Therefore, the aim of the work was to develop a program to optimize the use of laser radiation in the treatment of diseases of the anorectal area. To achieve the goal, the research team was assigned the following research objectives:
- A computer module should be created, taking into account anthropometric data to optimize the beam power and the time of its exposure;
- The procedure for using laser treatment for diseases of the anorectal area should be personalized.
- Hemorrhoidal disease should be used as a biological model for writing an information computer program;
- A computer database should be created to minimize the risks of using lasers in the treatment of anorectal diseases
Materials and techniques
Research data on a sample of 362 patients treated with a diode laser within 3 years (2018–2020) were used to create a computer program. All patients had pathologies of the anorectal area. Surgical treatment of all patients was performed using a diode laser. The creation of the program involved the use of databases that contained anthropometric data of patients – height and weight, technical parameters of laser radiation – wavelength, beam power, and exposure time.
When utilizing the device in test run mode, a laser tool proves to be convenient for application: the device is easy to use (PLUG & PLAY technology is used, which simplifies the detection of a hardware component in the system without the need for user intervention), compact, convenient for transportation and use in various medical facilities during the working day. The interface placed on the touch screen uses the Russian language, as well as makes it possible to quickly use several operating modes when performing surgical interventions, sometimes even in one patient. Straight and radial light guides were used for all surgical interventions, with the 1.46‑micron radiation wavelength applied.
Hemorrhoidal disease was chosen as a biological model when writing the program. Straight light guides were used to treat hemorrhoids that resulted in the response of “white denaturation” of tissues. Sometimes the wounds were additionally stitched with a 3–0 Vicryl suture by means of a round needle for the purpose of additional hemostasis and mucosa lifting. When using radial light guides, the light guide was inserted percutaneously into the submucosal layer, and coagulation of hemorrhoids was carried out fanwise. The operation was carried out using a laser beam power of up to 8 W, with no response of “white denaturation” of tissues observed. Mucosal prolapse was lifted with a 3–0 Vicryl suture by means of a round needle. During the postoperative period, the pain syndrome was minimal and subsided on the 2nd day after the surgery, and the average period of disability was 10–12 days. The analysis of the pain syndrome was carried out using the Numeric Pain Rating Scale (NPRS).
The pain syndrome was 3–4 points when using straight light guides, 1–2 points when using radial light guides, by the 3rd day no pain syndrome was observed. All patients underwent epidural anesthesia (362 cases). This type of anesthesia involves the introduction of an anesthetic in the immediate vicinity of the spinal cord. Therefore, they are united by the concept of “central anesthesia”. In order to prevent the development of arterial hypotension, patients are subjected to volemic (infusion) load with solutions of crystalloids or solutions of colloids if necessary. This leads to an increase in preload and, consequently, to an increase in venous return and normalization of cardiac output. Dynamic monitoring of blood pressure, pulse, respiratory rate, and pulse oximetry is carried out during the initial examination of the patient, during preparation and anesthesia, as well as during the postoperative period.
It is implicit that devices that can be used for such treatment have also been proposed previously. For example, similar equipment using mechanical compression, ultrasound diagnostics, and ultrasound coagulation is proposed by Jimin Zhang et al [6].
The main difference between the use of laser radiation and ultrasonic heating or non-monochromatic photocoagulation is that it is capable of providing a selective effect on tissues with the right choice of radiation wavelength. This means that the use of laser radiation to solve the problem of blood coagulation in a vessel results in relatively low heating of the surrounding tissues [3].
For efficient coagulation of blood, radiation should be absorbed by hemoglobin to good effect, while the absorption of radiation by the tissues surrounding the vessel should be less so that the principle of selection is in place. To solve the problem of laser coagulation, it is also advisable to use a pulse-periodic mode of exposure, which will increase the efficiency of blood coagulation and ensure the safety of surrounding tissues due to a smaller heating zone.
It is also important to note the minimally invasive and convenient ways of delivering laser radiation to the affected area. Laser radiation is delivered to the area of exposure in the tissue thickness via a flexible optical fiber of small diameter using lenses, and the coagulation process itself can be carried out using endovasal laser obliteration and through the tissue [3, 5, 7–10].
Laser radiation has a number of other advantages: the area of thermal damage is kept sterile and does not exceed 0.15 mm. Coagulation of blood and lymph in the lumen of small vessels with a diameter of 0.3–0.5 mm provides hemostasis and lymphostases, which completely eliminates bleeding from the wound and the development of congestive edema of surrounding tissues [11,12].
Description of the laser equipment
To perform the research, the laser equipment is used (Fig.1) based on the ACT DUAL diode medical laser manufactured by Yurikon-Group LLC with radiation output through a radial optical fiber with a lens [12].
Radiation with a wavelength of 1470 nm is used. The power and duration of exposure varies widely – power up to 16 W, duration of exposure in one pulse up to 1000 ms. The total exposure time can be set by anyone, since any number of repetitive pulses is set.
Program Description
The developed program is equipped with an intuitive interface (Fig. 2). To calculate a personalized mathematical model, several input parameters (wavelength, exposure temperature, patient’s skin type, laser beam diameter, and power) should be entered. It is also necessary to enter the patient’s data, namely: full name, gender, and age. After calculations are made, the interface allows the surgeon to see how the temperature of the tissue will change when the laser is exposed to the biological tissue at different times and different depths from the surface and along the beam section.
The calculated parameters and patient data are recorded in the program database (Fig. 3), which can be used to collect anonymous statistics for the purpose of further development of the program and procedure.
The following algorithm is used to calculate the mathematical model:
1. The temperature variation of the cylinder in question that is under the influence of the laser in the horizontal and vertical directions should be calculated as follows:
, (1)
where C is the heat capacity of the biological tissue, mi is the mass of the cylinder in question at the integration step, Qi is the amount of heat transferred, i is the step number.
2. The amount of heat transferred between the layers due to diffusion should be calculated as follows:
, (2)
where S is the cross-section area, di is the cross-section diameter at the step, is the coefficient of thermal conductivity, dt is the time step of the integration;
2. Calculations, as specified in clauses 1 and 2, should be recursively performed until the calculated temperature of the layer with a given depth (Formula 3) is equal to the set temperature.
. (3)
The constants used by the program (reflection coefficients, heat capacity and thermal conductivity of biological tissue) necessary for calculation are made available in Table 2.
Discussion of the Results Obtained
The results of the developed algorithm employed and the program applied are presented below. A total of 362 patients were treated, the distribution of which by gender, age, and diagnosis of the disease is shown in Figures 4–6.
Without using a calculation program, the treatment algorithm provided for setting the output power of the diode laser at 10 W and varying the exposure time in the range of 800–3200 ms, depending on the diameter of the treated area as a subjective choice of the surgeon. On the one hand, this caused excessive tissue damage, on the other hand, repeated treatment was required in certain cases.
The use of the calculation program eliminated this downside. Consequently, the choice of parameters of the impacting laser radiation became personalized. As can be seen from the diagram in Fig.7, for 41.45% of patients, the laser radiation power was reduced by 20%, and for 29.57%, the power had to be reduced even by 30%.
The diagram in Fig.8 shows that the exposure time had to be significantly increased up to 12,000 ms for almost 16% of patients. But the surgery was completed in 1 cycle without having to apply the exposure repeatedly.
Conclusion
Consideration of the anthropometric parameters facilitates optimizing the radiation power, which further improves the morphometric parameters of the wound process, as well as reduces the wound healing period.
All these data were taken into account when writing the computer program, the following parameters were entered – the patient’s height, weight, exposure time in seconds, wavelength, radiation power in watts. All these data were further processed and laser exposure was personalized using mathematical modeling methods.
The developed software can be used to personalize the laser effect on the tissues individually for each patient. The biological model – hemorrhoids – requires further development of cytological and histological parameters, with individual data to be taken into account.
The development of software improvement based on the created model, taking into account the risk measuring parameters, will expand the potential of the application of diode lasers in coloproctology. And this method of laser surgery will be widely used by doctors.
ABOUT AUTHORS
Nikita Kirillovich Zhizhin. Senior Researcher, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of surgical treatment procedure.
ORCID: 0000-0002-7825-3556
Dmitry Alekseyevich Ivanov. Principal Software Engineer, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of user programs, databases.
ORCID: 0000-0001-9381-0747
Maxim Alekseyevich Ivanov. Head of the Laboratory, Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of a software algorithm for the implementation of a mathematical model.
ORCID: 0000-0003-2738-0990
Yuriy Yuriyevich Kolbas. Deputy Head of Research and Manufacturing Complex‑470,
Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Creation of a mathematical model.
ORCID: 0000-0002-6867-0065
Yevgeny Viktorovich Kuznetsov. General Director, Doctor of Engineering Science, Professor. Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of calculation procedure
ORCID: 0000-0002-3530-478x
Nadezhda Alekseyevna Kuzina. Research and Development Institute “Polyus” named after M. F. Stelmakh, Moscow. Completed tasks: Development of a patient database.
ORCID: 0000-0001-5594-1260
Yelena Anatolyevna Shibeko. Head of the Therapeutic Department Federal Medical Center of the Federal Property Management Agency.
Completed tasks: Development of post-surgery treatment procedure and collection of patient data.
ORCID: 0000-0001-6356-0089
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