A tissue-adaptive method for ultrasonic cutting hemostatic scalpel

Abstract

This invention relates to a tissue-adaptive method for ultrasonic cutting hemostatic knives. It solves the problem of existing ultrasonic cutting hemostatic knives having a single operating power and poor coagulation effect for different blood vessel walls. It includes S1, using an ultrasonic knives to grasp the tissue to be grasped; S2, identifying the type of tissue to be grasped; S3, adjusting the dynamic impedance value of the ultrasonic knives according to the properties of the grasped tissue; and S4, changing the operating frequency of the ultrasonic knives at different time intervals during tissue cutting. The advantages of this invention are: it can automatically adjust the output power during cutting according to different tissues, improving cutting effect and tissue coagulation ability.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and more specifically to a tissue adaptation method for an ultrasonic cutting hemostatic knife. Background Technology

[0002] Ultrasonic cutting hemostatic scalpels are typically driven by a constant power or constant current to achieve optimal cutting speed. However, in actual surgery, due to the varying densities, hardness, and fluid content of different tissues—for example, certain cancerous tissues and the ovarian suspensory ligaments have relatively high density and hardness—if the ultrasonic scalpel is driven by a single constant power or constant current, it can easily lead to prolonged cutting time, a rapid increase in scalpel tip temperature, and severe tissue carbonization. For vascular tissue, because there are significant differences in vessel diameter and the wall thickness of veins and arteries, an ultrasonic scalpel driven by a single constant power or constant current may have good cutting and coagulation effects on some vessels with similar characteristics, but its coagulation effect is poor on vessels with varying wall thicknesses. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned problems by providing a clamping device for welding pipe fittings.

[0004] To achieve the above objectives, the present invention employs the following technical solution: a tissue adaptive method for an ultrasonic cutting hemostatic scalpel, the method comprising the following steps:

[0005] S1. Use an ultrasonic scalpel to clamp the tissue that needs to be clamped;

[0006] S2. Identify the type of tissue being sandwiched;

[0007] S3. Adjust the dynamic impedance value of the dynamic ultrasonic scalpel according to the properties of the tissue being clamped.

[0008] S4. During the tissue cutting process, the working frequency of the ultrasonic scalpel is changed in different time periods.

[0009] By recognizing the tissue being grasped, the ultrasonic scalpel flexibly changes its dynamic impedance under excitation based on differences in tissue density, viscosity, and strain. During the cutting process, it adjusts the working frequency of the ultrasonic scalpel according to the cutting time period. It can automatically adjust and output specific power values ​​for different tissues, effectively enhancing the coagulation ability of blood vessels, adapting to a variety of different tissues, and controlling the cutting speed and blade temperature within an ideal range, thereby improving the cutting effect of the ultrasonic scalpel.

[0010] In step S1, after the ultrasonic scalpel receives the start signal, it starts outputting at the frequency at the end of the last cut. The phase difference and phase lead-lag relationship of the feedback voltage and current are detected in real time. The PID algorithm is used to control the frequency change step size to quickly find the resonant frequency.

[0011] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, step S2 specifically includes the following steps:

[0012] S21. The ultrasonic scalpel main unit operates at constant power, driving the transducer and scalpel head to vibrate;

[0013] S22. Collect the current, voltage, and impedance values ​​during the operation of the transducer using a PID control model;

[0014] S23. Acquire the resonant frequency value of the cutting head through the PID control model;

[0015] S24. Calculate the impedance slope and frequency slope using the calculation formula;

[0016] S25. Compare the calculation results with the data in the frequency slope vector table, and take the closest data to obtain the tissue type.

[0017] By collecting data through a PID control model, we can ensure the accuracy of the data and make the output more stable.

[0018] In the tissue-adaptive method for ultrasonic cutting hemostatic knives described above, the calculation formula is as follows:

[0019]

[0020] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, the frequency slope vector table is as follows:

[0021] ;

[0022] Each pair of rows represents the parameters of the starting impedance (kn0), ending impedance (kn1), impedance change rate (k(n+1)0), and frequency change rate (k(n+1)1) of a characteristic organization.

[0023] In the tissue adaptive method for ultrasonic cutting hemostatic knife described above, in step S3, when the ultrasonic scalpel head grasps the tissue, due to the differences in density, viscosity and strain of each tissue, the dynamic impedance has significant differences. The dynamic impedance performance changes in real time according to the different tissue changes, so that the tissue moisture evaporates quickly.

[0024] The ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance change rate decreases significantly, the saved impedance change rate and frequency change rate are compared with the pre-stored frequency slope vector table to determine the tissue type.

[0025] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, in step S4, the time periods are as follows:

[0026] a. Time period 0-t1: Organizational judgment phase;

[0027] b. t1-t2 time period: constant power cutting stage;

[0028] c. The time period from t2 to t3: the cutting is complete.

[0029] During the 0-t1 time period, the initial impedance, final impedance, impedance change rate, and frequency change rate of each tissue are compiled into a 2-column, m-row frequency slope vector table. This frequency slope vector table is pre-stored in the host memory. Each time the system starts working and reaches the t1 time period, the four parameters of initial impedance, final impedance, impedance change rate, and frequency change rate are compared with the vector table. The data in rows n and n+1 that are closest to the frequency slope vector table are selected. That is, this tissue type is closest to the tissue in rows n and n+1. At the same time, the system pre-stores the power value that matches each characteristic value and applies the matching power value during the t1-t2 time period.

[0030] In the tissue adaptive method for ultrasonic cutting hemostatic knife described above, during the 0-t1 time period, the tissue has a high fluid content in the initial state. During this stage, the ultrasonic knife exhibits the ultrasonic knife cavitation effect, which causes the tissue water to evaporate rapidly.

[0031] During the 0-t1 time period, the ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance change rate decreases significantly, the saved impedance change rate and frequency change rate are compared with the pre-stored vector table to determine the tissue type.

[0032] A specific power level is applied according to the tissue type. For blood vessels, a smaller power value is applied compared to other tissues. Similarly, during this stage, the ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance slope starts to increase continuously, that is, when the t1-t2 time period is reached, coagulation is completed. During the working period of the ultrasonic scalpel, the tissue is coagulated and hemostasis is achieved through heat.

[0033] When identifying and cutting tissue, specific power values ​​are output at different time points, which can effectively enhance the coagulation ability of blood vessels according to the actual situation.

[0034] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, during the t1-t2 time period, the ultrasonic scalpel exhibits a mechanical effect as the liquid evaporates;

[0035] When the tissue is cut and severed, the ultrasonic scalpel head comes into contact with the tissue pad, causing changes in the impedance and operating frequency of the ultrasonic scalpel. The ultrasonic scalpel head heats up due to direct friction with the tissue pad, and the resonant frequency decreases.

[0036] During this phase, the resonant frequency rises briefly and then drops rapidly, indicating that the tissue has been completely severed. The ultrasonic scalpel contacts the tissue, and the heat from the scalpel tip rises rapidly, causing the resonant frequency to drop rapidly.

[0037] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, during the t2-t3 time period, the tissue cutting is completed, and the ultrasonic scalpel host actively reduces the energy output until the energy output stops.

[0038] During this stage, the ultrasonic scalpel gradually stops outputting energy and provides an audible signal indicating that the cutting is complete.

[0039] In the tissue adaptive method for ultrasonic cutting hemostatic scalpel described above, tissue coagulation and hemostasis are achieved through heat during the operation of the ultrasonic scalpel.

[0040] Compared with existing technologies, the advantages of this invention are: it can identify the tissue to be cut according to the calculation formula, and the ultrasonic scalpel outputs specific power at different time periods during the cutting process, thereby enhancing the coagulation ability of blood vessels, adapting to the cutting of various tissues, and controlling the cutting speed and cutting temperature of the ultrasonic scalpel head within a reasonable range, thus improving the cutting effect. Attached Figure Description

[0041] Figure 1 This is the equivalent circuit diagram of the ultrasonic scalpel in this invention;

[0042] Figure 2 This is a graph showing the impedance change of intestinal tissue during cutting in this invention.

[0043] Figure 3 This is a graph showing the frequency change of the mesangial tissue during cutting in this invention;

[0044] Figure 4 This is a schematic diagram of the PID control model principle in this invention;

[0045] Figure 5 This is a diagram showing the change in coagulation current in the 5mm brachial artery in this invention;

[0046] Figure 6 This is a graph showing the temperature change over a time period in this invention. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] A tissue-adaptive method for ultrasonic cutting hemostatic scalpel, comprising the following steps:

[0049] S1. Use an ultrasonic scalpel to clamp the tissue that needs to be clamped;

[0050] S2. Identify the type of tissue being sandwiched;

[0051] S3. Adjust the dynamic impedance value of the dynamic ultrasonic scalpel according to the properties of the tissue being clamped.

[0052] S4. During the tissue cutting process, the working frequency of the ultrasonic scalpel is changed in different time periods.

[0053] In step S1, after the ultrasonic scalpel receives the start signal, it starts outputting at the frequency at the end of the last cut. The phase difference and phase lead-lag relationship of the feedback voltage and current are detected in real time. The PID algorithm is used to control the frequency change step size to quickly find the resonant frequency.

[0054] Step S2 specifically includes the following steps:

[0055] S21. The ultrasonic scalpel main unit operates at constant power, driving the transducer and scalpel head to vibrate;

[0056] S22. Collect the current, voltage, and impedance values ​​during the operation of the transducer using a PID control model;

[0057] S23. Acquire the resonant frequency value of the cutting head through the PID control model;

[0058] S24. Calculate the impedance slope and frequency slope using the calculation formula;

[0059] S25. Compare the calculation results with the data in the frequency slope vector table, and take the closest data to obtain the tissue type.

[0060] The principle of the PID control model is as follows: Figure 4 As shown.

[0061] Furthermore, the calculation formula is as follows:

[0062] ,

[0063] In the formula: k: the cumulative value of the impedance or frequency change slope;

[0064] m: Number of times accumulated;

[0065] s: A calculation coefficient used to reduce calculation errors, such as s=100 when calculating impedance and s=10 when calculating frequency;

[0066] dy: The impedance difference and frequency difference between the two samples;

[0067] dt: The time interval between two samplings.

[0068] In detail, the frequency slope vector table is as follows:

[0069] ;

[0070] Each pair of rows represents the parameters of the starting impedance, ending impedance, rate of change of impedance, and rate of change of frequency for a specific type of organization.

[0071] like Figure 1-2 As shown, when the ultrasonic scalpel head grips tissue, the dynamic impedance R1 varies significantly due to differences in density, viscosity, and strain of different tissues. When cutting intestinal tissue, the dynamic impedance performance changes in real time according to tissue changes.

[0072] The frequency slope vector table was obtained through cutting experiments on a large number of different tissues, and the calculation formula yielded a vector table of impedance slope and frequency slope. Each row in the frequency slope vector represents the impedance and frequency characteristics of a tissue.

[0073] like Figure 6 The cutting temperature change graph shown below, in step S4, the time periods are as follows:

[0074] a. Time period 0-t1: Organizational judgment phase;

[0075] b. t1-t2 time period: constant power cutting stage;

[0076] c. The time period from t2 to t3: the cutting is complete.

[0077] By conducting numerous cutting experiments on several tissues of different sizes and thicknesses from different locations and tissues, during the 0-t1 time period, the initial impedance, final impedance, impedance change rate, and frequency change rate of each tissue were compiled into a 2-column m-row frequency slope vector table. This frequency slope vector table is pre-stored in the host memory. Each time the system starts working and reaches the t1 time period, the four parameters of initial impedance, final impedance, impedance change rate, and frequency change rate are compared with the vector table. The data in rows n and n+1 that are closest to the frequency slope vector table are selected, that is, the tissue type is closest to the tissue in rows n and n+1. At the same time, the system pre-stores the power value that matches each characteristic value, and applies the matching power value during the t1-t2 time period.

[0078] like Figure 2-3 As shown, during the 0-t1 time period, when the ultrasonic scalpel cuts the intestinal and mesenteric tissues, the tissues have a high fluid content in the initial state. During this stage, the ultrasonic scalpel exhibits the cavitation effect, which causes the tissue water to evaporate rapidly.

[0079] During the 0-t1 time period, the ultrasonic scalpel host outputs a constant current to drive the transducer and scalpel head to vibrate, thus preparing data for the PID control model to collect data.

[0080] The ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance change rate decreases significantly, the saved impedance change rate and frequency change rate are compared with the pre-stored vector table to determine the tissue type.

[0081] A specific power level is applied according to the tissue type. For blood vessels, a smaller power value is applied compared to other tissues. Similarly, during this stage, the ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance slope starts to increase continuously, that is, when the t1-t2 time period is reached, coagulation is completed. During the working period of the ultrasonic scalpel, the tissue is coagulated and hemostasis is achieved through heat.

[0082] During the t1-t2 time period, as the liquid evaporates, the ultrasonic scalpel exhibits both mechanical and thermal effects.

[0083] When the tissue is cut and severed, the ultrasonic scalpel head comes into contact with the tissue pad, causing changes in the impedance and operating frequency of the ultrasonic scalpel. The ultrasonic scalpel head heats up due to direct friction with the tissue pad, and the resonant frequency decreases.

[0084] During this phase, the resonant frequency rises briefly and then drops rapidly, indicating that the tissue has been completely severed. The ultrasonic scalpel contacts the tissue, and the heat from the scalpel tip rises rapidly, causing the resonant frequency to drop rapidly.

[0085] During the t2-t3 time period, the tissue cutting is completed, and the ultrasonic scalpel host actively reduces the energy output until it stops, extending the service life of the ultrasonic scalpel head.

[0086] like Figure 5 As shown, during the t1-t3 time period, based on the output current curve of the 5mm brachial artery vascular occlusion, it can be seen that specific power values ​​are output for different tissues, enhancing the vascular occlusion ability and adapting to the cutting of various different tissues, keeping the cutting speed and blade temperature within the ideal range. Subsequently, changes in the detection frequency are monitored. Figure 3 When the frequency changes during the t2-t3 time period, the tissue has been completely cut, and the host reduces the energy output until it stops.

[0087] The cutting and hemostasis of ultrasonic scalpel is based on mechanical effect, ultrasonic cavitation effect and thermal effect. Among them, mechanical effect is the main effect of ultrasonic scalpel cutting. High-frequency vibration causes tissue to stretch and generate tensile tension in the tissue. When the tensile tension exceeds the elastic limit of the tissue, the hydrogen bonds of protein molecules in the cell break, thereby producing a cutting and separation effect.

[0088] The ultrasonic cavitation effect occurs when an ultrasonic scalpel acts on tissue, causing a large number of small bubbles to be generated in the tissue fluid. Tensile stress occurs locally in the fluid, forming a negative pressure area. In this area, a large number of microbubbles in the cellular fluid expand rapidly and evaporate at low temperature, and then collapse at the tissue interface, resulting in the destruction of cell structure.

[0089] The thermal effect is generated when ultrasound waves, with their high frequency and energy, are absorbed by tissue. When the tissue temperature reaches above 60°C, proteins in the blood vessels denature, and broken protein hydrogen bonds reconnect, forming viscous coagulation proteins that seal the incision, achieving hemostasis. Simultaneously, the temperature rise caused by the thermal effect increases the activity of thrombin in the blood near the cutting tip area, accelerating the coagulation process.

[0090] During the operation of the ultrasonic scalpel, heat is used to achieve coagulation and hemostasis of the tissue.

[0091] Furthermore, the main source of heat is:

[0092] 1. Generated by high-speed vibration of the blade and friction with the tissue;

[0093] 2. Heat generated by ultrasonic cavitation effect;

[0094] 3. The vibration of the blade causes the protein molecules in the tissue to vibrate, thereby generating stress and strain inside the tissue, which are then converted into viscoelastic heat energy.

[0095] Frictional heat and viscoelastic heat are the main sources of heat for blood clotting. During ultrasonic scalpel cutting, tissue stress and the coefficient of friction determine the amount of heat generated by viscoelastic heat and frictional heat. The amount of heat accumulated by the cutting head varies for different tissues, and the mechanical properties also differ. These mechanical properties and heat can affect the drift of the cutting head's resonant frequency.

[0096] In summary, the principle of this embodiment is as follows: the ultrasonic scalpel clamps the tissue to be cut with constant power, the PID control model is used to collect the operating data of the transducer and the ultrasonic scalpel, and the impedance slope and frequency slope are calculated by calculation formula. The calculation results are compared with the data in the frequency slope vector table to obtain the type of the clamped tissue.

[0097] The ultrasonic scalpel automatically adjusts its output power according to tissue type and time period, thereby regulating the cutting speed and temperature of the ultrasonic scalpel head during different cutting processes, and thus enhancing the coagulation effect of blood vessels.

[0098] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A tissue-adaptive method for ultrasonic cutting hemostatic scalpels, characterized in that, This method includes the following steps: S1. Use an ultrasonic scalpel to remove the required tissue; S2. Identify the type of tissue being sandwiched; S3. Adjust the dynamic impedance value of the ultrasonic scalpel according to the properties of the tissue being gripped; S4. During the tissue cutting process, the working frequency of the ultrasonic scalpel is changed in different time periods. Step S2 specifically includes the following steps: S21. The ultrasonic scalpel main unit operates at constant power, driving the transducer and scalpel head to vibrate; S22. Collect the current, voltage, and impedance values ​​during the operation of the transducer using a PID control model; S23. Acquire the resonant frequency value of the cutting head through the PID control model; S24. Calculate the impedance slope and frequency slope using the calculation formula; S25. Compare the calculation results with the data in the frequency slope vector table, and take the closest data to obtain the type of tissue. The calculation formula is as follows: ， In the formula, k: The cumulative value of the slope of impedance or frequency change; m: Number of times accumulated; s: A calculation coefficient to reduce calculation errors; dy: The impedance difference and frequency difference between the two samples; dt: the time interval between two samplings; The frequency slope vector table is as follows: ； Each pair of rows represents the parameters of the starting impedance, ending impedance, rate of change of impedance, and rate of change of frequency for a specific type of organization. In step S4, the time periods are as follows: a. Time period 0-t1: Organizational judgment phase; b. t1-t2 time period: constant power cutting stage; c. Time period t2-t3: Cutting completed; During the 0-t1 time period, the initial impedance, final impedance, impedance change rate, and frequency change rate of each tissue are compiled into a 2-column, m-row frequency slope vector table. This frequency slope vector table is pre-stored in the host memory. Each time the system starts working and reaches the t1 time period, the four parameters of initial impedance, final impedance, impedance change rate, and frequency change rate are compared with the vector table. The data in rows n and n+1 that are closest to the frequency slope vector table are selected. That is, this tissue type is closest to the tissue in rows n and n+1. At the same time, the system pre-stores the power value that matches each characteristic value and applies the matching power value during the t1-t2 time period.

2. The tissue adaptive method for an ultrasonic cutting hemostatic scalpel according to claim 1, in step S1, after the ultrasonic scalpel obtains the start signal, it starts outputting at the frequency at the end of the last cutting, and detects the phase difference and phase lead-lag relationship of the feedback voltage and current in real time, and uses a PID algorithm to control the frequency change step size to quickly find the resonant frequency.

3. The tissue adaptive method for an ultrasonic cutting hemostatic scalpel according to claim 1, characterized in that, In step S3, when the ultrasonic scalpel head grasps tissue, the dynamic impedance varies significantly due to the differences in density, viscosity, and strain of each tissue. The dynamic impedance performance changes in real time according to the changes in different tissues. The ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance change rate decreases significantly, the saved impedance change rate and frequency change rate are compared with the pre-stored frequency slope vector table to determine the tissue type.

4. A tissue adaptive method for an ultrasonic cutting hemostatic scalpel according to claim 3, characterized in that, During the 0-t1 time period, the tissue has a high fluid content in its initial state. During this stage, the ultrasonic scalpel exhibits the cavitation effect of the ultrasonic scalpel, causing the tissue water to evaporate rapidly. During the 0-t1 time period, the ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance change rate decreases significantly, the saved impedance change rate and frequency change rate are compared with the pre-stored vector table to determine the tissue type. A specific power level is applied according to the tissue type. For blood vessels, a smaller power value is applied compared to other tissues. Similarly, during this stage, the ultrasonic scalpel host samples, calculates, and saves the impedance value and resonant frequency every 2ms. The ultrasonic scalpel host calculates and saves the impedance and frequency change rate every 20ms. When the impedance slope starts to increase continuously, that is, when the t1-t2 time period is reached, coagulation is completed. During the working period of the ultrasonic scalpel, the tissue is coagulated and hemostasis is achieved through heat.

5. A tissue adaptive method for an ultrasonic cutting hemostatic scalpel according to claim 4, characterized in that, During the t1-t2 time period, as the fluid in the tissue evaporates, the ultrasonic scalpel exhibits both mechanical and thermal effects. When the tissue is cut and severed, the ultrasonic scalpel head comes into contact with the tissue pad, and the impedance value and operating frequency of the ultrasonic scalpel change. The ultrasonic scalpel head rubs directly against the tissue pad, causing the ultrasonic scalpel head to heat up and the resonant frequency to decrease. During this phase, the resonant frequency rises briefly and then drops rapidly, indicating that the tissue has been completely severed. The ultrasonic scalpel contacts the tissue, and the heat from the scalpel tip rises rapidly, causing the resonant frequency to drop rapidly.

6. A tissue adaptive method for an ultrasonic cutting hemostatic scalpel according to claim 5, characterized in that, During the t2-t3 time period, the tissue cutting is completed, and the ultrasonic scalpel host actively reduces the energy output until it stops. During this stage, the ultrasonic scalpel host gradually stops the energy output and provides an audible prompt that the cutting is complete.

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