UA44805C2 - A METHOD OF CONNECTING SOFT BIOLOGICAL FABRICS AND DEVICES FOR ITS IMPLEMENTATION - Google Patents

Abstract

The method of connecting soft biological tissues and the device for its implementation provide for joining the tissue edges through high-frequency bipolar coagulation. The tissue edges are brought together and pressed with the electrodes. Then the high-frequency current is applied through the tissues being connected with the heating resulting in the intensive coagulation of the proteins. The heating is realized by the gradually increasing high-frequency voltage at the first stage followed by the fixed high-frequency voltage at the second stage. The high-frequency voltage is modulated by the low-frequency rectangular pulses. The high-frequency voltage is chosen within 20-100 V range and the frequency – within 50 kHz – 1.5 MHz range depending on the depth of the tissue layer and the type of the tissue under treatment. The highest voltage and the low frequency are employed for joining the thick tissue layers while the lowest voltage and high frequency – for joining the thin tissue layers. The low-frequency modulation is chosen within 4-20 Hz range also depending on the depth of the tissue layer and the type of the tissue under treatment. The pressure applied to tissue edges being joined is chosen within 0.5(106 – 2(106 Pа taking into account the properties of the tissues with further 1.2-2.0-fold increase at the end of the second stage to increase the strenth of tissue joining. The device for connecting soft biological tissues comprises the power supply with the transformer and the detectors of the current and voltage.

Description

Description of the invention

The invention relates to medicine and veterinary medicine, and more precisely to surgery. An ancient way of connecting 2 tissues and walls of organs after injuries and surgical manipulations is their stitching with threads of different structure and nature. Such suture materials can be non-absorbable and absorbable, natural and synthetic, mono- and multifilament.

Advantages of the suture method of fabric connection: - the strength of the performed seam both in the immediate and in the remote postoperative period; 70 - tightness of seams and the possibility of overlapping them in several rows overlapping each other; - relative simplicity and availability of tools -- needle holders, multi- and single-charge needles; the familiarity of a method developed over centuries. Disadvantages of the method: - leaving foreign material in the tissues (temporary -- for absorbable threads and permanent -- for threads made of mylar, propylene, metal wire); 19 - overcompression of suture tissues, which significantly affects the course of wound healing (temporary - for absorbable sutures and long-term - for non-absorbable sutures), which lead to the development of chronic inflammation in the tissues, the formation of "thread" complications, the elimination of which sometimes exceeds the complexity of the main surgical intervention; - allergic effect on the tissues of biological suture materials, which leads to festering of the wound; - thousand-fold potentiation of wound infection threads in wounds, which contributes to the development of postoperative complications; - forced leaving of suture material in wounds (in deep layers), which leads to an uncontrolled reaction of body tissues to them (cutting sutures in the walls of the gastrointestinal tract, respiratory tract, urinary tract); calcifications on threads in the biliary, urinary tracts and stomach. p. 29 These circumstances constantly cause the search for alternative ways of connecting fabrics, mainly seamless. Go)

Mechanical suturing with wire staples accelerates and simplifies the connection of tissues, but requires expensive and sometimes disposable equipment that can cause self-removal of staples and the development of microabscesses in the tissues of the most important organs, deformations and cicatricial narrowing of anastomoses.

Fabric gluing with synthetic and biological glues has the following advantages: o 30 - ease of application of adhesive preparations; Ha") by the speed of their transition to the solid state; the formation of hermetic connections; the possibility of manipulation in hard-to-reach places. co

Disadvantages: "And - by leaving a significant mass of adhesive film in the tissues, which prevents the healing of wounds; 325 - the toxic effect of most glues on fabrics; c - the formation of bedsores with the subsequent development of inflammation and the formation of fistulas; - weakening of the biological adhesive film and difficulties in preparing such an adhesive from donor blood in connection with the threat of HIV infection of patients; "- the high cost of medical adhesives and a small range of their varieties. Since 50 In recent years, for the connection of hollow organs, various protectors, rings, magnetic devices have become widespread, which have only one advantage - the speed of performing surgical manipulations with their help, and all

Iz" defects characteristic of foreign bodies left in the tissues for different periods of time.

Attempts to use laser devices for thermal adhesion are associated with the inconvenience of this method of welding tissues due to the peculiarities of the means of delivering the laser beam and its behavior with 45 limitations of the amount of heating in the depth of tissues with the high cost of laser equipment and non-standard equipment for manipulation. This method has not gained clinical distribution, despite its ten-year "" history and experience in the use of lasers in surgery and medicine.

Ultrasonic welding of fabrics remains questionable. The prototype of the proposed invention is high-frequency bipolar coagulation (Doletsky S.Ya., Drabkin R.L., Lenyushkin A.Y. High-frequency av! 20 zlektrohirurigia. -- M.: Medicine, 1980. -P.6-11).

The use of high-frequency currents in surgery has been known since the first quarter of our century. Thanks to the high-frequency sl current, vessels are sealed in surgical practice in order to stop bleeding (formation of hemostasis). High frequency currents are used for cutting fabrics. At the same time, small vessels are sealed simultaneously with cutting. In addition, various cauterizations are performed with high-frequency currents to eliminate the affected surface layers of tissues.

GF) The expected effect is achieved due to the property of the fabric to conduct an electric current. The current heats the tissue. The globular proteins present in the tissue are long molecules twisted into balls. When heated in the temperature range of 55...100 "С, the molecules are straightened and entangled - coagulation occurs.

Compressed walls of blood vessels during coagulation are united into one whole, due to which bleeding becomes impossible. 60 If you heat the fabric with an electric current above 100 "C, it will lose moisture, its resistance will increase, which will lead to a further increase in temperature and destruction of the fabric. This principle is based on the cutting of the fabric by the current flowing through it. The greatest heat release occurs near the scalpel, to near the edge of the scalpel with the tissue, the highest current density is 2" and therefore the highest energy release per unit volume. This part of the tissues is destroyed, forming an incision, the edges of which undergo thermal coagulation.

Bipolar and monopolar instruments are used to create hemostasis. A bipolar instrument is a pair of tweezers, the branches (or consoles) of which are isolated from each other and connected to a high-frequency generator. To seal the vessel, it must be pressed with such tweezers and a high-frequency voltage applied to the branch. An electric current will flow through the compressed walls of the vessel, which heats the tissue to a temperature at which intense protein coagulation occurs, which ensures the connection of the compressed walls of the vessel and stops the flow of blood through it.

The monopolar instrument consists of two parts: an active electrode in the form of a thin rod attached to one of the generator poles, and a passive electrode in the form of a flexible conductive 7/0 plate with a large surface attached to the second pole of the generator. The latter is placed under the body of the person undergoing surgery. The monopolar tool is used for cutting tissue, burns, and also for closing small vessels. The electrical circuit is closed through the active electrode, the tissue, the passive electrode and the high frequency power source. For the formation of hemostasis, a monopolar tool is less effective than a bipolar one, because the coagulation zone when using this tool is limited to a very small area in /5 immediate proximity to the tool.

The known experience of connection by means of high-frequency electrocoagulation of dissections of the aorta and veins along (5idaeei! V.,

OYumpp M. Te tespapizt oi Briood mevzve! siovyge ru podp iedcepsu eIesigosoadshiayop // Zygd., sSypesoYodu

Orzieiigisv. -- Osioreg 1965. -- R.823-831). Equipment designed to stop bleeding was used to restore the functions of damaged vessels. One of the main conclusions made by the authors of this work, 2o, is that this equipment and methods of performing the operation in this case do not allow to achieve the desired results. New equipment and means of its use are needed to minimize the undesirable effects of the high-frequency current on the tissues of the vessel walls and, above all, "excessive coagulation".

The closest to the declared device is the device. (Egre Viroyag No-tody! Veiervpa

Zepiseapieyita. p. 34, iid. 1), intended for electrocoagulation of vascular tissues. ch 4

The device consists of a transformer 1 connected to the network, a rectifier 2, a pulse regulator and)

C, an inverter with a high-frequency output transformer 4 and a pass-through capacitor 5, a cable 6 and a bipolar instrument 7. A pulse regulator stabilizes the voltage at the input of the inverter. The level of the stabilized voltage is regulated by a potentiometer, in addition, the device includes a foot switch, by pressing the MU, the surgeon turns on the device, and when it is released, it stops its operation. Due to the fact that the voltage is not smoothed after the rectifier, the pulse regulator works only during those periods of time when the voltage on the output capacitor of the regulator is greater than the instantaneous value of the rectified voltage. The device is equipped with a sound signal. The inverter is tuned to a frequency of about 300 kHz. The frequency is not adjustable.

Sealing of blood vessels - the formation of hemostasis using high frequency currents requires careful preparation of the instrument, especially the working surfaces of the electrodes, and the selection of the heating mode. If the necessary conditions for performing hemostasis are not met accurately enough, the joint is not formed or joint defects occur in the form of excessive burning, accompanied by tissue sticking to the instrument, and sometimes charring.

Efforts to reduce the probability of formation of defects consisted, first of all, in the search for information about the flow of the coagulation process so that it was possible to use this information for automatic control.

Thus, the US patent No. 4938761 "Viroiag eiesiosygodisa! rgosegv" provides for temperature measurement;» electrodes In the best case, it is possible to measure the temperature of the electrode at the point of its contact with the tissue. This information can be used for automatic control to prevent overheating of this contact and reduce the likelihood of tissue sticking to the electrode. However, this information does not reflect the true nature of the coagulation process in the inner layers of the tissue, which are subject to connection due to its sufficiently low thermal conductivity and relatively short time for the formation of the connection. ve German Patent No. 3838840 "Nospitedcep2 Koadshayopv-ogispipo iigo spigogdizpe meske" provides for the installation of two temperature sensors (thermocouples).

The first sensor is mounted in the current-carrying electrode, and the second - in the passive part of the instrument. o The difference in data is proportional to the excess temperature of the electrode relative to the temperature of the surrounding space. This technical solution, like the previous one, does not allow obtaining the necessary information about the course of tissue coagulation at the site of formation of the connection.

Several patents are known that protect methods of controlling the process of vascular coagulation: US patent Mo dv 4139759 "Misgorgosezzog sopigoei eiesigozygoisa! depegag", European patent Mo 0316469 "Nidn ytedcepsu zygdisa!| demise (o scsi apa og sozdshiayop bBiiodisa! yizztsev", German patent Mo 4009819 "NON-Spygydiedega!".

Ф) Yes, the European standard MO 0316469 provides for the stabilization of the voltage applied to the instrument through ka feedback, which acts on the power amplifier. US patent No. 4739759 provides for the use of microprocessor control of the voltage applied to the instrument without any feedback that reflects the coagulation process.

German patent Mo 4009819 protects a similar device with microprocessor control, which stabilizes the voltage at the input of the RF generator. The possibility of modulation is provided.

There is information about the creation of control systems (see Romadanov S.S. Zlektrohiruricheskie vysokochastotnie apparatii. -- Kyiv: DmP Polymed), which work either in the power stabilization mode, or in the 65 current or output voltage stabilization mode.

If the output current or voltage exceeds the preset values, the control system turns on the voltage stabilization mode. The main operating mode of the device is the power stabilization mode. It is also indicated (page 19) that a high-frequency signal (500...1760 kHz) must be modulated by a lower frequency signal (20...75 kHz). Unfortunately, according to the functional scheme given in the indicated literary source, it is impossible to imagine the constructive implementation of the device.

According to the author, such control systems increase the safety of the patient and the reliability of the device by eliminating dangerous uncontrolled modes.

The most perfect method of automatic control is described in the article MaeShoge et al. petozviais demise".

Through direct measurements, it was established that tissue impedance changes dramatically during coagulation.

At first it is large, and then decreases, reaches a minimum and increases again. Such dependence of impedance on time is used for control. The specified patent shows the functional scheme of the control system.

It is envisaged to determine the influence of strulg and voltage on the tissue of the vessel, calculation of the current /5 value of the tissue impedance based on these data, determination of the impedance function, detection of whether the current impedance function is within the normal range or not, and if it is not, the heating of the tissue is stopped with an indication of whether another way of error. If the current impedance function deviates from the preset current value, the control system acts on the power supply to reduce the error. Fabric heating stops when the current impedance function reaches the set value.

The structure of the system that performs control according to the described algorithm is not mentioned in the literature known to us, including patent literature.

The well-known British patent Mo 2213381 "EIesigo-vygodisa! arragayi5 m/yy Iodu itredapse topiyuhipd", which provides a unit for registering instantaneous values of voltage and current. The machine adjusts the impedance above a set level and produces a warning or control signal, which, according to the patent, allows the surgeon to operate even if the operation site is out of his line of sight.

Note that this patent protects only part of the control system functions in the above patent and)

USA Mo 5403312.

Management of the coagulation process by tissue impedance is a certain step forward on the way to improving the equipment for electrocoagulation of blood vessels. However, it is still impossible to consider the problem of managing the coagulation process as finally solved, if we have in mind the more general problem of connecting different soft tissues. Our experiments showed that the impedance of tissue 7, other things being equal, varies widely. It is influenced by uncontrollable or difficult-to-control factors, such as the type of fabric, the thickness of the layer captured by the tool, the structure of the fabric, the condition of its surface and the surface of the tool, and others.

Based on what has been said, the state of the art prior to this application can be briefly formulated as follows: "- high-frequency electrocoagulation, in particular bipolar, is used to seal blood vessels (formation of hemostasis) without the possibility of restoring their functions; the experience of using high-frequency electrocoagulation to restore the functions of damaged vessels, which dates back to 1965, did not develop due to the insurmountable effects of the high-frequency current on the tissues of the vessel walls and, above all, "excessive coagulation"; "- there is no known experience of using high-frequency electrocoagulation to connect the tissues of other damaged organs in order to restore their functions; - a well-known device for high-frequency electrocoagulation of blood vessels with a voltage stabilization system on;" surgical instrument; - a known method of automatic control of the hemostasis formation process based on the electrical impedance of the tissue of the compressed vessel or on the speed of its change. The general disadvantage of all three listed known solutions is that the scope of their possible use is limited only to the formation of hemostasis, that is, the sealing of vessels without further restoration of their functions. o The main task of the proposed method and device is to improve the known method due to the fact that the heating is carried out in two stages, the heating parameters of each stage are determined for the connection of thick (tissues of the intestine, stomach, liver, etc.), thin tissues (epineurium and etc.) with the help of additional input of current and voltage sensors, as well as their connection with the existing elements of the device, which allows, due to the coagulation of proteins when heating the tissue with a high-frequency electric current, to restore the functions of the tissue and thereby improve the quality of its connection. 5B The task is achieved by the fact that in the method of connecting soft biological tissues, in which the edges of the connected layers of tissues are brought together and a high-frequency electric current is passed through the compressed tissue for

F) heating it to the temperature at which intensive coagulation of the protein contained in the tissue occurs, and the heating of the tissue is carried out in two stages. At the first stage, a constantly increasing voltage is applied. This stage ends when the resistance of the tissue reaches a minimum value, and the second stage proceeds at a constant voltage, because that corresponds to the end of the first stage, and is modulated by low-frequency pulses, for example, rectangular

Pulses, while the value of the constant voltage is chosen in the range from 20 to 100 V, the frequency of the current - from 50 kHz to 1.5 MHz, and the highest voltages and low frequencies are used to connect thick (tissues of intestines, stomach, liver, etc. ) of tissue layers, and the lowest voltages and high frequencies are for connecting thin (epineurium, etc.) tissue layers, while the tissue compression pressure is chosen in the range from 0.5-105 to 3-109 Pa, and 65 at the end of the second stages of heating increase it by 1.2...2.0 times and then remove it after 0.5...1.0s after turning off the current.

In addition, the modulation frequency of the current flowing through the fabric is chosen in the range from 4 to 20 Hz, and low modulation frequencies are used for thick layers of fabric, and slightly higher frequencies for thin layers.

At the end of the first stage of heating, the resistance of the fabric 7 is measured and, if it is greater or less, for

Limit values are set, heating is stopped.

The voltage drop on the fabric Sh and the current I flowing through it are determined through the voltage OO, the current im at the input of the high-frequency generator according to the formulas 0 - Ku -Kepu and /- Ko, where:

Ku and K»o are constant coefficients;

Ke is the equivalent resistance determined experimentally. 70 The resistance of fabric 7 is determined by the following relationship: 2 - SHO/, where:

I-- current;

Oh - the voltage on the electrodes, which is equal to the voltage drop on the fabric.

If it is greater or less than pre-set limit values, the heating of the tissue is stopped.

During the heating process, the minimum resistance of the fabric 7 ldip is determined, after which the relative resistance 7 is determined according to the following dependence: 2- 2/etc. and in the event that the relative resistance 7 reaches an experimentally determined value in advance, which corresponds to the formation of a connection, the heating of the fabrics is stopped.

The first stage of heating is carried out at a preset optimal speed for the tissues of this organ, and the increase in voltage is stopped when the resistance reaches a minimum value of 7 dip, and in the second stage, the heating of the tissues is stopped when 2 reaches a certain value, which corresponds to the formation of connections.

In addition, the task is also achieved by the fact that in the device for connecting soft biological tissues, which consists of a power source, which includes: a transformer, the output of which is connected to the filter capacity and the first input of the pulse regulator, the output of the latter connected to the first input of the inverter, the output of the inverter is connected to the surgical instrument through a pass-through capacitor, -- there are current and voltage sensors connected to the input of the inverter, and the outputs of these sensors are connected to sch g through a communication device input of the computer, the outputs of the latter - through the same communication device are connected by means of two separate control devices to the second input of the pulse regulator and to the second input of the inverter.

Heating of the connected areas of the fabric with a high-frequency current flowing through it is carried out in two stages, the first of which takes place with a constantly increasing voltage drop on the fabric, and the second - with a constant, modulated by low-frequency pulses, the stages are carried out using a current sensor and a voltage sensor, which are connected through a communication device with the object and with a computer, which contains several programs for controlling the welding process of various types of fabrics, which are made according to experimental data. at

The current modulation frequency is selected using the inverter, which transmits the corresponding signal through the device in communication with the object of the inverter control unit.

The selection of the compression force of the fabric depending on its type, thickness and stabilization of this force in the process of "heating the fabric with its increase at the end of heating is carried out with the help of high-frequency voltage from the "E inverter, which passes through the pass-through capacitors along the cable to the clamping tool, which connects areas of tissue.

Fabric resistance 7; and 7 are calculated using the above formulas using developed programs.

Automatic termination of the heating process after the relative impedance of the fabric reaches a pre-determined value, and the relative impedance is defined as the ratio of its current to the minimum in s value, which is observed directly in the process of forming the next connection, which is carried out using a current sensor and a voltage sensor. As soon as the current relative value of the impedance reaches the given ;" chain value: computer-object communication device-control unit with pulse regulator-pulse regulator -- a signal is received to reduce the output voltage of the pulse regulator

TO zero. The sound signal coming from the computer disappears, thanks to which the surgeon receives information about the end of heating the tissue, after which it is possible to remove the welding tool from the tissue.

The automation of determining the voltage drop for the second stage of tissue heating is carried out by measuring the current value of the tissue impedance at the first stage of heating, stopping the elevation and

Go! further stabilization of the voltage at the level corresponding to the minimum resistance value.

The improvement of the power source with the inverter is carried out due to the introduction of new blocks, such as the block for controlling the transistors of the pulse regulator and the control block for the inverter, as well as the presence of additional connections between the blocks.

The process of connecting tissues with subsequent restoration of their biological functions should be much more flexible and gentle than the process of sealing blood vessels. This is due to the greater variety of tissues that have to be connected, the difference in their properties, as well as the fact that during the formation of anastomoses, much larger volumes of tissues are affected than when sealing individual vessels. For the successful healing of anastomoses, it is necessary that (F) the amount of damaged tissue is minimal, and the damage itself is not too deep, that is, there is no "recoagulation".

The list of drawings in Fig. 1. Dependencies of high-frequency voltage O, current | and electrical resistance of tissue 2 from time (without modulation): a -- low voltage; b -- average; in -- high.

Fig. 2. Dependencies of the change in the effective value of the high-frequency voltage o) and the force of compression by the electrodes of the fabric P on time.

Fig. 3. Automatic control (stopping the heating of the fabric according to the relative resistance 2 - 2/2 65 - Fig. 4. Automatic control with elements of self-adjustment of voltage and the end of heating according to the relative resistance.

Fig. 5. Scheme of a power supply With an automatic control system.

Fig. 6. Boiling of intestines "side to side".

Fig. 7. Boiling of the liver.

Fig. 8. Boiling of the gall bladder.

Fig. 9. Nerve welding.

The essence of the invention 1. The formation of the contact is based on the following basic provisions: the electrodes with the tissue and the conducting /o channel (the first stage of tissue heating) are carried out by gradually increasing the high-frequency voltage on the electrodes, which excludes local overheating of the tissue or electrode-tissue contact.

Soft biological tissue consists of cells and intercellular fluid. Cells are limited by membranes that differ in high electrical resistance. Various ions, including proteins that carry charges in the solution, participate in the conduction of electric current. Since the membranes have weak conductivity, two adjacent 7/5 Cells can be considered as some kind of non-ideal capacitor.

In this regard, the tissue located between the electrodes can be imagined as a three-dimensional matrix, the constituent element of which is a capacitor, connected in series with the active resistance of the cell protoplasm and shunted by a large resistance through which the leakage current flows.

The formation of a monolithic coagulum, which unites together the connected tissues, can be imagined only when the membranes are torn and the protoplasms of the cells fuse. This process of fusion with subsequent coagulation probably proceeds in two directions.

The first direction is cell membrane penetration. This process proceeds gradually, requires an investment of energy, and has a chain character to some extent. Electrical penetration of the membrane must be prepared by heating and can occur at certain combinations of electric field strength and temperature. Breakthrough begins with cells that have the weakest or poorly oriented membranes. The intensity of the electric field on cells with punctured membranes decreases and, accordingly, increases on cells with still intact membranes. and)

The probability of breaking through the next cells increases, etc.

This process of reducing the electrical resistance of the fabric is confirmed by direct measurements (Fig. 1).

It is significant that the greater the voltage applied to the electrodes, the more significantly the resistance decreases. Another circumstance that should be paid attention to is that the increase in the volume of the captured tissue leads to a delay in the process of increasing the conductivity of the tissue due to the penetration of cells. It cannot be argued that these rules of dependence are enforced too strictly. Changes in tissue structure from operation to operation also have an effect. co

The second direction is tissue deformation under the action of electrode pressure. Under pressure, the tissue is stretched in a direction perpendicular to the axis of the electrodes. At high pressure, purely mechanical rupture is also possible - from5 some membranes. After electrical penetration, such rupture becomes more likely. "Mr

With a constant potential difference between the electrodes, deformation of the tissue is accompanied by an increase in the voltage of the electric field, which contributes to the penetration of membranes.

Thus, the initial stage of tissue heating is the formation of a continuous conduction chain.

Excessive acceleration of this process leads to local overheating of the fabric and an increase in the probability of its sticking to the tool. with c 2. Heating of the tissue (second stage) is carried out at a constant value of the high-frequency voltage on the electrodes. Thanks to this, the conditions for the formation of the connection are stabilized. Naturally, an anastomosis is formed;" successive formation of a number of compounds. Each previous connection electrically shunts the new connection that is formed. With a constant voltage drop across the electrodes, the shunt effect is reduced to

At least their Z. The frequency of the current is chosen depending on the type of fabric. Usually, when creating equipment for electrosurgery, the current frequency is chosen in the frequency range from 3000 to 2000 kHz. This range of pi currents is not felt by animals and humans. Apart from this unconditional indicator, no others, of course, are mentioned.

Go! We decided to check if this is the case.

We conducted special experiments in a wide range of frequencies, in particular, it was established that the best frequency for rat intestines is 50 kHz, at which we obtain the strongest connection and a strength dispersion close to the minimum. The frequency of 50 kHz is practically not perceived by the body and its use is possible. For the very thin tissue that surrounds the nerve column, a frequency of 1000 kHz is best. The effect of frequency on the strength of the connection is caused by the features of the formation and the geometry of the zone with broken integrity of the membranes. 4. The high-frequency voltage is modulated by low-frequency pulses from 4 to 20 Hz. in particular rectangular (Fig. 5).

F) For the coagulation process, which occurs with energy absorption, not only the temperature is important, but also the time spent at this temperature. As a special analysis showed, with low-frequency modulation, the necessary coagulation takes place with lower energy consumption and a lower temperature than with a continuous mode of heating.

Modulation with a frequency of 1 kHz does not give such an effect. 5. The fabric is heated when it is compressed by electrodes with a pressure of 0.5 to 3.0 (or 2.0) MPa, depending on the type of fabric. By the end of the second stage of heating, the pressure is increased by 1.2-2 times (Fig. 3).

Pressure is one of the main parameters that determine the welding mode. The pressure determines the process of formation b5 of the conductive channel, ensures the rupture of membranes, necessary for the formation of a monolithic coagulum.

Increasing the pressure at the end of the second stage of heating allows, as shown by direct experiments, to increase the strength of the connection by 10...20905. 6. During the operation, the surgeon does not have the opportunity to select the welding mode, which ensures the connection of the required quality. The only possible way that ensures the possibility of using welding in practical surgery is the use of computer technology. The surgeon must tell the computer the type of animal, its age, the operated organ, the type of tissue, and based on this information, the computer reproduces the welding mode that is in its memory, close to the optimal one. It is also necessary to provide for the correction of the regime by the surgeon himself, which he can perform during the operation, as well as by the computer during welding, taking into account the specific characteristics of the animal and possible obstacles (disturbances) associated with the conditions of the operation. 70 7. The following are among the probable disturbances affecting the welding process: a) contamination of the working surfaces of the electrodes; b) changing the thickness of the welded fabric layers; c) fluctuations in the force of tissue compression by electrodes; d) current shunting through adjacent areas of the tissue; e) inhomogeneities of the fabric falling into the zone of formation of the connection; f) increased temperature of the electrodes; g) variable state of the fabric surface (dry, wet, with traces of blood, etc.).

The automatic control system through appropriate feedback should change the heating mode 2o so that the spillover of disturbances is minimal. 8. Information about the progress of the process is obtained by changing the current values of the voltage on the electrodes and the current, dividing these values gives the current value of the tissue impedance. If by the end of the first stage of heating, which occurs at a gradually increasing voltage, the impedance has not decreased to the previously established value, which indicates, in particular, contamination of the working surfaces of the electrodes, then the heating of the tissue is stopped in order to avoid its excessive injury. For the same purpose, the heating process is interrupted at any moment if the impedance of the tissue is lower than the preset limit, which indicates i) compression of the tissue by the electrodes. 9. Control of the welding process with feedback, which stabilizes the dependence of tissue impedance on time or the rate of its change, is used, as already indicated above, in the sealing of blood vessels. We have no experience with the use of such control systems, and we have doubts about their success use even on the same type of fabric. Many factors affect the resistance of the tissue sandwiched between the electrodes. co

It is possible to more effectively stabilize the quality of the connection through automatic control, if you switch from the absolute resistance value to the relative one (Fig. 3). For this, during the heating process, determine "

Зз5 is the current value of tissue impedance. "Mr

But remember its minimum value of 7 grands, which is reached at a certain stage of heating the fabric.

Then they continue to determine the current value of the resistance and divide it by the nominal value, thus obtaining a relative value of 2 h. After reaching 7, a predetermined value, which corresponds to the moment of formation of a connection of the required quality, the heating is stopped. With the transition to management by relative value allows you to free yourself from the influence of many hard-to-control factors. ;" 10. For control, the values of many mode parameters are required, which should be defined in advance. However, many features of any particular connection may not be taken into account. Therefore, it is advisable to build the automatic regulation system in such a way that it includes elements of self-adjustment. For this, the initial stage of tissue heating is carried out by gradually increasing the voltage on the electrodes at a speed previously selected for this type of tissue. At the same time, the current value of resistance in the tissue is measured. When the resistance of the tissue reaches a minimum, the increase in voltage stops and stabilizes it at

Go! reached level (Fig. 4) At the same time, the minimum impedance values of 7 grandfathers are memorized, and then the relative current impedance value is determined. After reaching 7 preset values, the heating is stopped. sp Thus, they achieve a higher degree of probability of formation of connections of the required quality. 11. Direct measurements of current and voltage, determination of tissue impedance during connection formation are associated with a number of difficulties. We are primarily interested in the thermal effect created in the fabric by high-frequency currents. Therefore, we can limit ourselves to measuring the current and voltage at the inverter input. At a small no-load current of the high-frequency transformer, the current consumed by the inverter is proportional to the current,

F) flowing through the tissue. The voltage at the inverter input is proportional to the active voltage drop in the inverter-transformer-cable-tool-fabric circuit. Efficiency of the height energy conversion and transmission system.

Therefore, the voltage at the input of the inverter can be considered proportional to the voltage drop on the fabric. To implement the above-described method of connecting soft tissues, a power source is required - a high-frequency current generator controlled by a computer or a microprocessor device. Due to the fact that the surgeon does not have the opportunity to select the mode directly during the operation, the memory of the control device must contain all the necessary information for the tissues of various organs. Among them are: - frequency of alternating current of high frequency; 65 - alternating current modulation frequency; - rate of increase in alternating current voltage (first stage of heating);

- voltage drop on the fabric (second stage of heating); - the time taken from the moment of the start of heating to the moment of increasing the compression force of the tissue (if a tool with pressure stabilization at two levels is used); - heating time.

Upon the surgeon's call, the specified information is automatically entered into the control device and played during the operation. It is possible to correct the regimen by the surgeon during the operation, if necessary. Correction can be carried out only on one parameter - high-frequency alternating current voltage.

In addition, the surgeon must receive information from the computer about the recommended dimensions of the working surface of 7/o electrodes and the force of tissue compression by them during welding, in order to avoid errors when choosing a tool.

If the method is used, in which the termination of heating is carried out at certain values relative to the impedance of the tissue, then the memory of the control device must contain data on these parameters for all organs on which it is possible to perform operations. In this case, the heating time data is only used for control functions. In particular, if the actual heating time turned out to be 1.5-2 times greater or less than /5 times that contained in the memory, the control device signals this to the surgeon so that he adjusts the high-frequency voltage in a greater or lesser direction. When using the method with adaptation elements, the voltage drop on the fabric is not introduced into the control device (the second stage of heating) - this voltage is fixed automatically when the resistance of the fabric reaches the minimum value. The voltage stabilizes at the reached level by the end of the second stage of heating. The latter is completed when the relative resistance reaches the specified level. Data on the heating time, as in the previous case, are used only for control functions. If this one. time is significantly different from what is stored in the memory, the control device gives a signal to the surgeon about this. If the actual time is different from the recommended time, the surgeon must introduce a correction for the rate of increase of the high-frequency voltage.

The device required for welding soft biological tissues (Fig. 5) consists of a power source A, a control system B, a cable C of a surgical instrument O, and a control pedal E. The power source includes: transformer 1, rectifier 2 , filter C, pulse regulator 4, inverter 5, pass-through capacitors 6, current 7 and voltage sensors 8, pulse regulator control units 9 (executed as an electronic unit based on a specialized pulse-width modulator chip), and inverter control unit 10 (made in the form of an electronic block based on a rectangular pulse generator with a frequency of 880 kHz). The control system consists of a communication device with the object 11 and a computer (or microprocessor device 12). The communication device with the object is connected to the pedal E, which the surgeon presses and starts the program for controlling the welding process, which is contained in the computer. co

Blocks 9 and 10 perform the function of matching the outputs of the communication device with the object with the input of the pulse regulator 4 and the inverter 5. The communication of the device 11 with the pulse regulator is carried out by an analog signal, proportional to the set output voltage of the regulator, and with the inverter by a digital signal by the code that sets the frequency "g of the inverter.

The computer memory contains several programs for controlling the welding process for different types of fabrics.

Using traditional means of communication with the computer, the surgeon finds the program he needs and informs the computer about it. Then the surgeon prepares the joint of tissue for its welding, compresses the sections of tissue to be welded with a welding tool, after which he presses /- with his foot on pedal E, which starts the program selected by the surgeon to control the welding process. From the computer 12, thanks to the devices 11 and 9, a signal proportional to the desired is received at the input of the pulse regulator;" gradually increasing output voltage. The computer notifies the surgeon about this with the help of a sound signal.

Along with this, signals proportional to current and voltage are received from sensors 7 and 8. After conversion into digital form, these signals are sent to the computer, where the current value of the impedance 7 is determined by means of the voltage-to-current division.

If the calculated current value is 7 less than the previous one, the voltage increases at the rate specified by the program. If, on the contrary, the current value of the impedance is greater than the previous one, the computer gives

Go! to the impulse regulator, the task corresponding to the stabilization of the output voltage of the regulator at the achieved level.

At the same time, the computer remembers the impedance as its minimum value of 7 pip. o At the next stage, the determination of the current value 7 continues, which is then divided by the computer into its minimum value of 7 pip. The result of division - the relative current resistance is compared by the computer with its limit value set by the control program.

As soon as the current relative value of the impedance reaches the specified value, a signal is sent through the circuit 12-11-9-4 to reduce the output voltage of the pulse regulator to zero. The sound signal coming from the computer disappears, thanks to which the surgeon receives information about the end of heating the tissue, after which (F, it is possible to remove the welding tool from the tissue. ka A digital code comes through the chain 12-11-10-5, which sets the frequency of the inverter, which depends on the selected welding process control program. v The communication device has two inputs connected to the current sensors 7 and voltage 8, two-way communication with the computer 12. One of the outputs of the communication device with the object is connected to the control unit of the pulse regulator 9, the other - to the control unit of the inverter 5.

In addition, the surgeon receives information via the sound channel of the computer about the activation of the device, about the premature termination of heating and, about the reasons for this disconnection, about the welding time exceeding the optimal limits for this tissue.

Thus, in the proposed method of connecting soft biological tissues, the edges of the tissue layers are brought together,

compress them and pass a high-frequency electric current through the compressed tissue to heat it to a temperature at which intensive coagulation of the protein contained in the tissue occurs. Fabrics are heated in two stages. At the first stage, a constantly increasing voltage is applied, and at the second - a constant voltage, modulated by low-frequency, for example, rectangular pulses. In this case, the value of the constant voltage is chosen in the range from 20 to 1008, the frequency of the current - in the range from 50 kHz to 1.5 MHz, and the highest voltage values, and low frequencies are used to connect thick (tissues of the intestine, stomach, liver and etc.) of tissue layers, the lowest voltages and high frequencies -- for connecting thin (epineurium, etc.) tissue layers. In this case, the fabric compression pressure is chosen in the range from 0.5-109 Pa to 3-105 Pa at the end of the second stage of heating 70, it is increased by 1.2...2.0 times and then removed after 0.5... 1.0s after power off.

The modulation frequency of the current flowing through the fabric is chosen within 4...20 Hz, and low modulation frequencies are used for thick layers of fabric, and higher frequencies are used for thin layers.

At the end of the first stage of heating, the fabric resistance is measured 7. and if it is greater or less than the established limit values, the heating of the fabric is stopped.

The voltage drop on the fabric M and the current I flowing through it are determined by the voltage Ц and the current I at the input of the high-frequency generator according to the formulas

I-Kk(, Ke/ta

IeKoi, where:

Ku and K." -- constant coefficients; Ke is the equivalent resistance determined experimentally.

The impedance of the tissue 7 is determined by the dependence 4 - Ц//, where:

I-- current; y -- the voltage on the electrodes, which is equal to the voltage drop on the fabric, and if it is greater or less than the pre-set limit values, the heating of the fabric is stopped. with

In the heating process, the minimum impedance of 72 pip is determined, after which the relative impedance of 7 is determined according to the dependence: 2 -2/2ur | if the relative impedance 7 reaches a previously experimentally determined o value corresponding to the formation of a connection, stop heating the tissues.

The first stage of tissue heating is carried out at the optimum speed set in advance for the tissues of one organ, and the increase in voltage is stopped when the resistance reaches a minimum value of 7 dip, and in the second stage, tissue heating is stopped when 7 reaches a certain value that corresponds to the formation of connections. -

Before starting work, the primary winding of transformer 1 is connected to the network. The secondary voltage from the transformer is rectified by rectifier 2, the capacitance C is charged to the amplitude value of the secondary voltage. The pulse regulator 4 is in the closed state, the inverter 5 is de-energized. WITH

In order to start welding, the surgeon presses the pedal E, which gives a signal to start playing the mode "I welding, which is in the memory of the computer 12. The computer 12 through the communication device 11 gives signals to the devices 9 and 10 The conductivity of the pulse generator 4 is restored. The voltage and current at the input of the inverter 5 are monitored by the computer using sensors 7, 8 and a communication device. As soon as this voltage reaches the value determined by the program, the computer, through device 11 and device 9, closes the regulator 4. The next switching on 70 of the regulator 4 occurs after a time interval determined by the frequency of the pulse regulator. - s Simultaneously with the appearance of voltage, the inverter 5 begins to work with a frequency determined by the program available in the computer's memory, which transmits the corresponding analog signal through the device 11 of the block 10. 6 comes through the cable C to the clamp of the tool 0, which compresses the connected sections of the fabric.

After completing the program, the computer turns off the regulator through devices 11 and 9. "" Reactivation is carried out by the surgeon by pressing pedal 13 again. Devices of use: e I. Electrowelding of the large intestine of rabbits "side by side" (Fig. b). (ee) Under anesthesia, the large intestine is crossed and a 3...5 cm long segment is expanded. The ends of the intestine are turned in the form of 2...3 mm long cuffs, the mucous membrane is stretched and welded with a continuous suture, successively moving the welding tweezers with electrodes along the plane 2 mm? (1x2 mm). By pressing on the sl segment of the intestine, the tightness of the seams is checked, the cuffs are turned back and, in the same way, a gray-serous seam is performed.

After sealing the ends of the segments of the intestine, they are brought together with their side surfaces and the serous membranes of the segments are welded along the length of the intended dissection (length 2...4 cm) and at a distance of 4...5 mm from each other (a). Outside and parallel to the superimposed seroserous suture in the longitudinal direction, all layers of the intestinal wall are dissected (c) and bleeding from individual vessels is stopped with the same welding tweezers in the "coagulation" mode.

Electrical welding of the mucosal-submucosal layer of the anastomosis is performed, starting from its deep 60th part (c, 4) and moving circularly to the outer wall. They pay special attention to the processing of "corners", which is also observed when applying ordinary seams (e, y).

The final stage of the operation is the overlay of the external connection of the serous membranes (a-y). After checking by palpation the patency of the anastomosis and its impermeability to the contents left in the intestine, the anastomosis is considered complete, the wound of the abdominal wall is closed. 65 Welding mode:

Voltage - 45 V (gray-serous suture) 40 V (mucosal-muscular suture)

The pulse passage time is 1.2 and 14 s

Current frequency - 50 kHz

The voltage increase time is 150 ms

The modulation frequency is 6 Hz

The effort is 3.5 N at the beginning and 5 N at the end.

During the execution of each connection, the tweezers branches were gradually compressed: 0.2 s - compression of the edges of the tissue with a force of 3.5 N for approximately 0.8 s, increasing the force to 5.0 N, 0.4 s - holding under the maximum force . 70 According to hydraulic tests of superimposed anastomoses, this mode provides maximum anastomosis strength. 2. Electrocoagulation of a parenchymal organ (rabbit liver) -- Fig. 10.

Under anesthesia, mark the line (a) of the intended marginal resection of the liver (for example, a segment with a length of 3 cm).

Along the edge of the intended dissection, linear electrowelding of the tissue (B) is carried out with bipolar tweezers with a height of Змм electrodes and a plane of 3...4 mm? (1x3 or 1x4 mm) in such a way as not to violate the integrity of the connective tissue capsule of the organ. Along the formed coagulation track, the marginal area is excised without blood and bile leakage (p. 4).

Manipulation mode:

The seam is continuous;

Voltage -- ЗО В;

Time - 1.2 s;

Frequency -- 50 kHz; Pulse increase time -- 150 ms; Modulation frequency -- 6 Hz; The thickness of the welded fabric is 5...8 mm; Compression force -4 N. Ha

C. Welding of the rabbit gall bladder wall (Fig. 11). Under anesthesia, bile is evacuated from the gallbladder cavity with a syringe through an injection needle (a). The gallbladder wall is dissected lengthwise. The length of the dissection is 9) 2.0...2.5 cm (B). Are the edges of the dissection at a depth of up to 1 mm compressed between the electrodes of the welding tweezers with a plane of 1 mm? and are welded together along the entire thickness of the fabric (c). After the application of the linear seam (c) is completed, a sheet of the omentum covering it on IV) is welded all the way through to reinforce it with single application of tweezers (in the clinic, this is not necessary, since the thickness of the wall allows applying a layer-by-layer anastomosis). Welding mode: Continuous seam; Voltage -- ЗО В; . Time - 1.2 s; Frequency -- 50 kHz; at

Pulse increase time -- 150 ms; Modulation frequency -- 6 Hz; The thickness of the welded fabric is 1 mm; Force C compression -- Z N. 4. Welding of nerves (Fig. 12).

The experiments were conducted on the sciatic nerve of a rat. After transection of the nerve (a) and hemostasis, excess fascicles were cut off. Two epineural sutures were applied with a 10/0 thread with an interval of 1807 along the circle (5) hE

The nerve was held by the handles and rotated to expose the posterior surface. With a bipolar microsurgical instrument, the epineurium was adapted along the back surface of the anastomosis, after which electrocoagulation was performed (c). The dimensions of the working surface of the electrodes are 0.4 x 0.5 mm. The manipulation was repeated in the direction "from one handle to the other (3...4 points, depending on the diameter of the nerve).

Then, in a similar way, the connection of the shells was carried out along the front surface of the anastomosis. Mode - with welding: Voltage -- 36 V; Welding time -- 50 s; Frequency -1000 kHz; Voltage increase time -- 15 ms; and Tissue compression force -- 0.3 N.» Advantages of the method: - the method is easy to use, requires the usual general surgical skills of operating on the stomach, intestines, liver, gall bladder and urinary bladder and other organs; t" - the method is carried out with the help of welding tweezers, familiar to surgeons, or simple devices, the use of which does not require special training; - the connection of fabrics can be made layer by layer or in bulk, the resulting seam is neat, aesthetic, (ee) airtight and reliable; o 50 - tests of the method on models of clinical operations in some types of animals (rabbits, white rats) showed its use in layer-by-layer closure of wounds, "end-to-end" and "end-to-side" intestinal welding, restoration of the integrity of the stomach, gall bladder and urinary bladder, which indicates the universality of the method and the possibility of expanding the range of clinical use; - absence of complications in the postoperative period in 90 95 animals, which could be associated with the use of the method itself, and not with mistakes in the introduction of anesthesia, technical errors of the surgeon; - the method reduces the duration of the operation by 50...60 95, facilitates the surgeon's work, makes it more rational and diverse; име) - surgeons who use the method for the first time, learn it without any particular complications, have a great desire to study it in more depth and apply it in their clinical practice. 60 Disadvantages of the method: - the possibility of tissue burns, which can be eliminated by automating the process and acquiring electrosurgical experience; - the initial strength of the anastomoses is less than with the sutural and mechanical suturing method, which does not significantly affect the outcome of the operation, but which requires some moral restructuring of surgeons. b5

Claims (8)

The formula of the invention 1. A method of connecting soft biological tissues, in which the edges of the connected layers of tissues are brought together and 2 a high-frequency electric current is passed through the compressed tissue to heat it to a temperature at which intensive coagulation of the protein contained in the tissue occurs, which differs in that tissue heating is carried out in two stages, in the first stage a constantly increasing voltage is applied, and in the second stage - a constant voltage modulated by low-frequency pulses, while the value of the constant voltage is chosen in the range from 20 to 100 V, the current frequency - from 50 kHz to 1.5 MHz, and the highest voltages and low frequencies 70 are used to connect thick (intestinal tissue, stomach, liver, etc.) tissue layers, and the lowest voltages and high frequencies to connect thin (epineurium, etc.) fabric layers, while the fabric compression pressure is chosen in the range from 0.5.109 to 3.105 Pa, and at the end of the second stage of heating, it is increased to 1.2...2.0 times and then removed after 0.5...1.0 sec. after turning off the current. 75 2. The method according to claim 1, which differs in that the modulation frequency of the current flowing through the fabric is chosen in the range from 4 to 20 Hz, and low modulation frequencies are used for thick layers of fabric, and slightly higher frequencies are used for thin layers. C. The method according to claim 1 or according to claims 1, 2, which differs in that at the end of the first stage of heating, the resistance of the fabric 7 is measured, and if it is greater or less than the set limit values, the heating is stopped. 20 4. The method according to item C, which differs in that the voltage drop on the fabric Ш and the current I flowing through it are determined through the voltage У,, the current im at the input of the high-frequency generator according to the formulas ШО - К/(Ц,, - Keiu) and I 2 Ko, where: Ku and K» are constant coefficients; KE - equivalent resistance, which is determined experimentally. 5. The method according to claim 1, which differs in that the determination of the impedance of the tissue 7 is carried out by dividing the drop of the voltage Ш 25 by the current I, which are determined by the formulas: (о) О0-КЦ,, - Ке. and) and! - Ka, where: Ц, and |, - voltage and current measured at the input of the inverter; yu 30 Ka. - equivalent resistance determined experimentally. b. The method according to claim 1 or claims 1, 2, which differs in that during the heating process, the minimum ("in") resistance of fabric 2 is determined, after which the relative resistance 7 is determined according to the following dependence: 2-2/7 kip and in the case, so if the relative resistance 2 reaches an experimentally determined value in advance, which corresponds to the formation of a connection, stop heating the tissues. "35 7. The method according to claim 1, which is distinguished by the fact that the first stage of heating is carried out at a pre-set optimal speed for the tissues of this organ, and the increase in voltage is stopped when the resistance reaches a minimum value of 7 pip, and in the second stage, tissue heating is stopped when 7 will reach a certain value corresponding to the formation of connections. 8. The device for connecting soft biological tissues consists of a power source, which "70 INCLUDES a transformer, the output of which is connected to the filter tank and the first input of the pulse regulator, and the output of the latter is connected to the first input inverter, the output of the inverter through a pass capacitor is connected to a surgical instrument, which differs in that it has current and voltage sensors connected to the input of the inverter, and the outputs of these sensors are connected through a communication device with the input of the computer, the outputs of the latter through the same communication device are connected by combining two separate control devices with the second input of the pulse regulator and with the second input of the inverter. sh» sh» (ee) o 50 sl F) ime) 60 b5