Medical instrument for percutaneous selective winding and unwinding of fascia connective tissue

Abstract

The invention relates to the technical field of medical instruments, and discloses a medical instrument for percutaneously and selectively rolling and removing fascia connective tissue, the instrument is composed of a driving part and a rolling and removing part, the driving part is used for driving the rolling and removing part to rotate, and the rolling and removing part is provided with a blunt head and a spiral rolling and removing groove. In clinical operation, after the rolling-off part is inserted into the fascia layer and is started to rotate, part of connective tissue in the fascia can be rolled off, separated and stored through the spiral rolling-off groove, and finally targeted taking-out is achieved. According to the invention, minimally invasive, controllable and continuous connective tissue reeling operation can be realized in a fascia layer densely accompanied by nerve endings. Through the innovative design, the pain symptom of a patient can be relieved immediately, the function of an affected part can be recovered quickly, and an efficient and safe novel solution is provided for clinical treatment of fascia related diseases.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a medical device for percutaneous selective rolling and removing of fascial connective tissue. BACKGROUND

[0002] Nerve endings are the terminal part of the peripheral nervous system, responsible for transmitting somatic sensation, visceral sensation and motor instructions to target organs. At the subcutaneous and intermuscular septal level, nerve endings often accompany fascial tissue. Fascial tissue includes superficial fascia and deep fascia. Superficial fascia is located between the deep layer of dermis and deep fascia, mainly composed of loose connective tissue, elastic fibers, fat lobules, and small blood vessels, lymphatic vessels, sensory nerve endings. Recent studies have shown that fascia not only has mechanical sliding and nutritional metabolism functions, but also is an important receptor distribution area of various chronic pain (such as fascial pain syndrome, postoperative adhesion pain, neuropathic pain). When fascia appears abnormal hyperplasia of collagen fibers, cross-linking and scarring due to trauma, inflammation or degeneration, the local tension increases, which can cause persistent mechanical stimulation to the sensory nerve endings passing through it, causing pain sensitization and dysfunction.

[0003] In view of the above pain mechanism, clinical treatment usually adopts physical therapy (shock wave, ultrasound, needle-knife release), chemical nerve block or oral analgesic drugs. However, these methods focus on symptom control and are difficult to fundamentally relieve the compression of abnormal connective tissue on nerve endings. In terms of surgical means, although there are open fasciotomy or endoscopic adhesion release, the incision is large and the operation level is deep, which is easy to damage the normal fascial sliding layer and accompanying blood vessels, and the risk of postoperative scar adhesion is high. Therefore, how to selectively remove the diseased connective tissue under minimally invasive conditions while preserving the integrity of the normal fascia and nerve structure has become a technical problem to be solved. SUMMARY

[0004] The present application provides a medical device for percutaneous selective rolling and removing of fascial connective tissue, which can assist the operator to selectively remove the fascial diseased connective tissue under minimally invasive conditions, relieve the patient's pain immediately, and restore the function of the patient's part; and the operation is simple, the learning curve is short, the operation time is short, and the operating room occupancy and the labor intensity of the operator can be significantly reduced.

[0005] The medical device for percutaneous selective rolling and removing of fascial connective tissue provided by the present application comprises a driving part and a rolling and removing part; the driving part is in transmission connection with the rolling and removing part for driving the rolling and removing part to rotate around its axis; the rolling and removing part has a blunt head and a spiral rolling and removing groove extending along its axial direction, and when the rolling and removing part rotates, part of the connective tissue of the fascia is rolled and separated by the spiral rolling and removing groove and is accommodated in the spiral rolling and removing groove.

[0006] In a possible implementation, the main body of the unwinding portion is cylindrical or tapered rod-shaped, one end of the main body is integrally formed with a blunt head, the spiral unwinding groove starts from the end face of the blunt head and extends spirally along the axis of the main body, the length of the spiral unwinding groove ranges from 1 to 5 cm, and the maximum depth is 3 mm.

[0007] In a possible implementation, the end face of the blunt head is a continuous smooth curved surface without cutting function, and the curvature radius is not less than 0.6 times the maximum diameter of the main body of the unwinding portion.

[0008] In a possible implementation, the main body of the unwinding portion is provided with a negative pressure passage, one end of the negative pressure passage is communicated with the spiral unwinding groove, and the other end is used to be communicated with a negative pressure device.

[0009] In a possible implementation, the driving portion includes a power supply unit, a direct current motor and a control unit; the power supply unit is electrically connected with the direct current motor and the control unit respectively to supply power for the direct current motor and the control unit; the control unit is electrically connected with the direct current motor to control the operation of the direct current motor to make the unwinding portion perform a rotating action.

[0010] In a possible implementation, the locked-rotor torque of the direct current motor ranges from 10 to 60 Nm, and the control unit is configured to: in the initial contact stage, control the direct current motor to output a set torque; in the unwinding traction stage, control the rotating speed of the direct current motor to linearly rise, and the output torque does not exceed a preset maximum limited torque; and in the high-tension cutting stage, control the direct current motor to output a set rotating speed.

[0011] In a possible implementation, the control unit is specifically configured to: when powered on, enter the initial contact stage, control the direct current motor to output a set torque; monitor the real-time current of the direct current motor; if the real-time current is greater than a preset first threshold value and the surge rate of the real-time current is greater than a preset second threshold value, enter the unwinding traction stage, control the rotating speed of the direct current motor to linearly rise, and the output torque does not exceed a preset maximum limited torque.

[0012] In a possible implementation, the control unit is specifically configured to: in the unwinding traction stage, if the real-time current is greater than a preset third threshold value and the fluctuation rate of the real-time current is less than a preset fourth threshold value, enter the high-tension cutting stage, and control the direct current motor to output a set rotating speed.

[0013] In a possible implementation, the control unit is further configured to: in the high-tension cutting stage, control the direct current motor to output the rotating speed in a pulse mode.

[0014] In one possible implementation, the set rotational speed includes a first rotational speed and a second rotational speed, the second rotational speed being less than the first rotational speed. If the winding direction is parallel to the fiber direction, the set rotational speed is the first rotational speed; if the winding resistance is small, the set rotational speed is the second rotational speed.

[0015] This invention provides a medical device for percutaneous selective fascial connective tissue removal, comprising a driving unit and a removal unit. The driving unit can drive the removal unit to rotate. The removal unit has a blunt head and a spiral removal groove. The blunt head, while performing blunt dissection, uses its spherical or oval surface to push outwards the tiny nerve endings and blood vessels passing through the fascia, forming a "mechanical avoidance zone." The spiral removal groove can produce a shearing-winding effect on collagen fibers, while minimizing the probability of damage to elastic fibers, fat lobules, and nerve structures. Thus, while relieving abnormal tension compression, it preserves a certain degree of integrity of sensory nerves. Therefore, using the medical device provided by this invention, a minimally invasive, controllable, and continuous connective tissue removal procedure can be performed in the fascial layer accompanying nerve endings, immediately relieving patient pain and restoring function to the affected area.

[0016] Furthermore, the medical device provided by this invention has an overall outer diameter of less than 5 mm for the roll-off part, which can be operated percutaneously under local anesthesia; the synergistic effect of the blunt head and the spiral groove reduces additional damage to the dermis, deep fascia and muscle layer, and no sutures are required or only a single needle is needed for closure after surgery, resulting in rapid wound healing and a significantly reduced scar formation rate after surgery.

[0017] Furthermore, the medical device provided by this invention is easy to operate and has a short learning curve. The roll-up part can be quickly connected to the drive part, and the surgeon only needs to control the needle insertion depth and the start and stop of rotation to complete all the roll-up steps. With the help of ultrasound or surface marking for positioning, the overall operation time, including anesthesia time, is shortened to within 60 minutes, which significantly reduces the occupancy of the operating room and the labor intensity of the surgeon.

[0018] This invention achieves "precise detachment" of connective tissue in fascial lesions for the first time, filling the technological gap in specialized instruments for nerve ending detachment surgery, and has significant clinical value and market prospects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the medical device for percutaneous selective fascia connective tissue provided in an embodiment of the present invention; Figure 2 is a schematic diagram of a rolling-off part structure of a medical instrument for transdermally selectively rolling off fascial connective tissue provided by an embodiment of the present application; Figure 3 is a control flowchart of a driving part of a medical instrument for transdermally selectively rolling off fascial connective tissue provided by an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor should fall within the scope of protection of the present application.

[0022] The terms "include", and other any variations thereof, in the specification and claims of the present application and the above-described drawings, refer to "including but not limited to", and are intended to cover non-exclusive inclusion, and are not limited to the examples listed in the text. In addition, the terms "first" and "second" and the like are used to distinguish different objects, rather than to describe a specific order.

[0023] First, the application scenario of the present application is described. As mentioned in the background, as of now, there is no medical instrument specially used for "transdermally selectively rolling off fascial connective tissue". The existing soft tissue biopsy instruments, such as spring biopsy needles and rotary biopsy devices, are designed to obtain solid tissue blocks or columnar cores, and it is difficult to achieve a series of continuous operations such as "directed rolling - continuous stripping - immediate removal". The blunt dissection cannula or fascial stripper commonly used in cosmetic surgery has problems of lack of precise control of rolling thickness, force, and nerve avoidance, and cannot remove fascial tissue from the body.

[0024] Based on the above status quo, the present application provides a special instrument, which can be transdermally punctured under local anesthesia to quantitatively, directionally and segmentally roll off fascial connective tissue. It can not only relieve nerve compression, but also maximize the preservation of fascial sliding function, which helps to relieve pain and restore the function of the corresponding part of the patient, and fills the gap in the current technical field.

[0025] The medical instrument for transdermally selectively rolling off fascial connective tissue disclosed in the present application is mainly improved in mechanical structure and motor control.

[0026] In terms of mechanical mechanism, the device has a specially designed unwinding part, which has a blunt head and a spiral unwinding groove. During the operation, the unwinding part can selectively produce shearing and winding storage effect on collagen fibers, and the damage to elastic fibers, fat lobules and nerve structures is minimal. In this way, while relieving abnormal tension compression, the sensory nerve can be kept intact to a certain extent.

[0027] In terms of motor control, considering that fascia tissue presents special mechanical properties during unwinding, i.e. fascia modulus changes with the degree of stretching, the texture is very soft at the initial stage, and the stiffness increases sharply after tightening. Based on this property, the application controls the DC motor in three stages to improve the unwinding effect and efficiency, reduce the operation difficulty and shorten the operation time.

[0028] The implementation of the application will be described in detail below in combination with specific drawings: Figure 1 A structure schematic diagram of a medical device for percutaneous selective unwinding of fascia connective tissue is provided for the embodiment of the application, Figure 2 A structure schematic diagram of the unwinding part of the medical device.

[0029] Referring to Figure 1 The medical device comprises a driving part 10 and an unwinding part 11; the driving part 10 is in transmission connection with the unwinding part 11, and the driving part 10 is used to drive the unwinding part 11 to rotate around its axis.

[0030] Referring to Figure 2 The unwinding part 11 has a blunt head 111 and a spiral unwinding groove 112 extending along its axial direction. When the unwinding part 11 rotates, it can cut off and separate part of the connective tissue of the fascia through the spiral unwinding groove 112 and store it in the spiral unwinding groove 112.

[0031] The device provided by the application is mainly used for surgical operation in the shallow fascia area, and can also be selectively used for surgical operation in some deep fascia area.

[0032] In the above design of the application, the blunt head 111 can be spherical or oval. This shape will not easily pierce or cut the tissue, and because the nerves and blood vessels are relatively soft and elastic, they will be pushed away when encountering the blunt spherical surface, while the collagen fibers are more tough and can be easily wound by the unwinding groove structure during rotation. Therefore, the blunt head 111 can separate the tissue while pushing the small nerve endings and blood vessels passing through the fascia to the outside to form a mechanical avoidance zone. This makes the spiral unwinding groove 112 only produce shearing and winding effect on collagen fibers, and the damage to elastic fibers, fat lobules and nerve structures is minimal, thereby relieving abnormal tension compression while keeping the sensory nerve intact to a certain extent.

[0033] In a specific implementation, the main body 110 of the roll-off part 11 can be cylindrical or tapered rod-shaped, one end of the main body 110 is integrally formed with a blunt head, and the spiral roll-off groove 112 starts from the end face of the blunt head 111 and extends spirally along the main body axis, the length of the spiral roll-off groove 112 can range from 1 to 5 centimeters, and the maximum depth can not exceed 3 millimeters.

[0034] In practical application, five types of roll-off parts can be provided, and the lengths of the spiral roll-off grooves of the five types of roll-off parts are 1 centimeter, 2 centimeters, 3 centimeters, 4 centimeters and 5 centimeters respectively. The specific selection of which type of roll-off part during surgery can be determined by the operator according to the specific surgical site and the severity of the patient's symptoms.

[0035] In practical application, each type of roll-off part can further include three different depths of spiral roll-off grooves, for example, spiral roll-off grooves with depths of 1 millimeter, 2 millimeters and 3 millimeters. Similarly, the operator can choose according to the specific surgical site and the severity of the patient's symptoms.

[0036] The embodiments of the present application provide a variety of types of roll-off parts for the operator to choose from, and the length and depth of the roll-off part instrument are matched, which can not only maintain a certain amount of roll-off to avoid excessive roll-off, but also help to shorten the operation time.

[0037] In a specific implementation, the end face of the blunt head 111 can be a continuous smooth curved surface (spherical or oval) without cutting function, and the curvature radius is not less than 0.6 times the maximum diameter of the roll-off part main body 110. This design is more helpful to achieve blunt separation of fascia, and at the same time, it can push the tiny nerve endings and blood vessels passing through the fascia to the outside to form a mechanical avoidance zone.

[0038] Referring to Figure 2 In another implementation, a negative pressure passage 113 can be provided in the main body of the roll-off part 11, one end of the negative pressure passage 113 is in communication with the spiral roll-off groove 112 (not shown in Figure 2 The other end is used to communicate with the negative pressure equipment.

[0039] In this embodiment, the negative pressure passage 113 can be a hollow passage provided in the roll-off part main body (integrally formed during production and manufacturing), or a hollow pipe inserted in the roll-off part main body. During surgery, the negative pressure passage 113 can be used to extract air inside the negative pressure passage 113 by a negative pressure device, so that the inside of the negative pressure passage 113 maintains a negative pressure state, which is conducive to the entry of the roll-off material into the groove and the retention of the roll-off material in the groove without falling off. After a roll-off is completed, the negative pressure passage 113 can also be filled with gas to make the roll-off material fall off quickly, which facilitates the progress of the operation.

[0040] Next, the improvement of the application in motor control is introduced. Considering that the mechanical properties of fascia tissue are different from conventional materials, the modulus of fascia changes with the degree of stretching during unwinding, and the modulus increases sharply after the initial stage of softening. Therefore, the unwinding force needs to be controlled to improve the unwinding effect and efficiency under the premise of safety. This is reflected in the control strategy of the control unit 103 of the driving part 10, which can accurately control the output of the DC motor 102 to match the mechanical properties of the fascia.

[0041] Referring to Figure 1 As shown in the figure, first, the architecture of the driving part 10 is introduced. In the embodiment of the application, the driving part 10 can include a power supply unit 101, a DC motor 102 and a control unit 103, wherein the power supply unit 101 is electrically connected with the DC motor 102 and the control unit 103 respectively, and supplies power to the DC motor 102 and the control unit 103; the control unit 103 is electrically connected with the DC motor 102, and controls the operation of the DC motor 102 to make the unwinding part 11 perform a rotating action.

[0042] It should be noted that in the embodiment of the application, the selected DC motor has a locked-rotor torque of not less than 10 Nm and not more than 60 Nm.

[0043] The so-called locked-rotor torque is the maximum torque that the DC motor can produce under the condition of zero speed and rated voltage, which reflects the ability of the motor to start and overcome large resistance. Setting the locked-rotor torque to be not less than 10 Nm can ensure that the DC motor has sufficient starting ability to ensure that the motor can successfully drive the load to start.

[0044] And the locked-rotor torque is limited to not more than 60 Nm, which is considered from the perspective of electrical protection and temperature rise limitation. Because the larger the locked-rotor torque is, the larger the corresponding locked-rotor current is. The locked-rotor current corresponding to this upper limit value is a key basis for designing power capacity, wire specifications and overcurrent protection devices (such as fuses, circuit breakers, etc.). The overcurrent protection device must act quickly when the motor generates a current reaching the upper limit due to locked-rotor to avoid the motor from being burned due to overheating and prevent safety accidents. When the motor is locked, a large amount of current is almost entirely converted into heat energy, and the current corresponding to the upper limit locked-rotor torque will cause the most serious instantaneous temperature rise. Although locked-rotor is a transient condition, its impact on the thermal state of the motor must be fully considered during the design process, especially in applications where frequent starting or accidental locked-rotor may occur.

[0045] In this embodiment, the control strategy of the control unit 103 is divided into three stages, namely the initial contact stage, the unwinding traction stage and the high-tension cutting stage.

[0046] In the initial contact stage, the DC motor is controlled to output a set torque. This stage uses constant torque output mode, which is independent of the rotation speed, and the purpose is to ensure that the connective tissue in contact with the spiral unwinding groove can be gently embedded.

[0047] Specifically, the initial contact stage refers to the period after the unwinding part enters the fascia layer and before it starts to rotate or just starts to rotate. At this time, the fascia presents an initial soft characteristic, and its Young's modulus is about 0.1 to 5 MPa. In this low strain state, the fascia has a viscous fluid characteristic. If a high rotation speed is used, the tissue will slip in the notch of the spiral unwinding groove and cannot be smoothly wound in. Therefore, by using a low rotation speed (non-constant) and high torque (constant) mode, the contacted tissue can be gently embedded in the spiral unwinding groove, preventing slipping and ensuring that the spiral unwinding groove can slowly bite the tissue.

[0048] For example, the set torque range can be 1 to 5 millinewton-meters, and the corresponding rotation speed is about 10 to 100 revolutions per minute (RPM). In this embodiment, the size of the set torque depends on the tissue resistance and the rotation radius of the instrument, and the tissue resistance depends on the effective contact area of the unwinding groove with the tissue, which can be determined according to the length and depth of the unwinding groove.

[0049] In this embodiment, the low rotation speed (non-constant) and high torque (constant) mode can make the tissue deform slowly and smoothly "bite" into the unwinding groove, effectively avoiding tissue slipping. This is because high rotation speed increases shear force, which can easily cause tissue to slip. The initial rotation speed can be set to 50 revolutions per minute, which can ensure the biting efficiency and safety. When the tissue resistance is not greater than the set constant torque, the motor can maintain the initial rotation speed; if the resistance is greater than the set constant torque, the rotation speed will decrease; when the resistance continues to increase and reaches a preset condition, it enters the unwinding traction stage.

[0050] In the unwinding traction stage, the control strategy is to control the rotation speed of the DC motor to linearly increase, and to ensure that the output torque does not exceed the preset maximum limited torque.

[0051] As the unwinding part continues to rotate in this stage, the collagen fibers will gradually align and tighten with rotation, and at this time the modulus of the fascia rises to about 5 to 20 MPa. Since the fascia has entered the "strain hardening" critical point, if the rotation speed is insufficient, the unwinding process may stop; if the rotation speed is too high, it may cause fiber rupture. Therefore, it is necessary to gradually increase the rotation speed to maintain the winding efficiency. In terms of specific implementation of the control strategy, the rotation speed of the DC motor is controlled to linearly increase.

[0052] For example, in the unwinding traction stage, the linear rising rate of the DC motor speed can be set as 100 RPM / s, which is beneficial to balance the winding efficiency and process stability. Meanwhile, the preset maximum limited torque is set as 8 mN*m. Generally, in the unwinding traction stage, the speed can be linearly raised to 600 rpm.

[0053] In the high-tension cutting stage, the DC motor can be controlled to output at a preset speed.

[0054] In the present embodiment, as the unwinding operation continuously advances, the stiffness of the fascia increases sharply, and the modulus is greater than 20 MPa. In this high modulus state, the brittleness of the tissue increases, and at this time, short-time high speed can be used to achieve the effect of "micro-invasive shearing". Therefore, in this stage, the DC motor can be controlled to operate at a preset high speed, and the already tightened tissue is cut off by high-speed rotation, thereby reducing tissue residues. For example, the preset speed in this stage can be 800 RPM.

[0055] The present application adapts to the nonlinear hardening characteristics of the fascia through the dynamic switching of the three stages of low-speed occlusion, medium-speed traction and high-speed disconnection, and fully considers the safety, convenience and efficiency of the unwinding operation. In the actual operation process, the operator can repeat the unwinding process by starting and stopping, and each start and stop can reuse the control strategy of the three-stage dynamic switching unwinding.

[0056] In the present embodiment, the change of the real-time current of the motor can be used to feedback the change of the mechanical properties of the fascia, and then trigger the switching of the three control stages.

[0057] Figure 3 is the control flowchart of the driving part of the medical instrument for percutaneous selective unwinding of fascial connective tissue provided in the present embodiment, as shown in the accompanying Figure 3 The specific process is as follows: Step 301, after power-on starting, enter the initial contact stage, control the DC motor to output at a preset torque; Step 302, monitor the real-time current of the DC motor; Step 303, if the real-time current is greater than a preset first threshold value, and the rising rate of the real-time current is greater than a preset second threshold value, enter the unwinding traction stage, control the speed of the DC motor to linearly rise, and the output torque does not exceed the preset maximum limited torque.

[0058] Step 304, in the unwinding traction stage, if the real-time current is greater than a preset third threshold value, and the fluctuation rate of the real-time current is less than a preset fourth threshold value, enter the high-tension cutting stage, control the DC motor to output at a preset speed.

[0059] In the present embodiment, the currents in different stages present different characteristics: Initial contact stage: the current slowly rises, generally the rising slope is not greater than 5% per second, which can be determined by monitoring the real-time current.

[0060] Roll-off traction stage: the current will linearly shake up, the slope is not less than 10% per second, which can be determined by monitoring the real-time current and the current rising rate.

[0061] High tension cutting stage: the current will appear high oscillation (±5%) or sudden drop (tissue rupture), which can also be determined by monitoring the real-time current value.

[0062] After the power is started, the system enters the initial contact stage, in which the control DC motor outputs according to the set torque. Then the real-time current of the DC motor is continuously monitored, once the real-time current is greater than the preset first threshold value and the real-time current rising rate is greater than the preset second threshold value, the system enters the roll-off traction stage. At this time, the speed of the control DC motor is linearly increased, while ensuring that the output torque does not exceed the preset maximum limited torque. In the roll-off traction stage, if the real-time current is greater than the preset third threshold value and the fluctuation rate of the real-time current is less than the preset fourth threshold value, the system enters the high tension cutting stage. In this stage, the control DC motor outputs according to the set speed.

[0063] The first threshold value, the second threshold value, the third threshold value and the fourth threshold value can be determined based on test data, which is not limited here.

[0064] The specific control method of controlling the DC motor to output according to the set torque in the initial contact stage, controlling the speed of the DC motor to linearly increase and ensuring that the output torque does not exceed the preset maximum limited torque in the roll-off traction stage, and controlling the DC motor to output according to the set speed in the high tension cutting stage will be introduced below.

[0065] It should be noted that the following specific control method is only an example and is not limited to this method. In fact, other control methods in the prior art can also achieve the control of the above-mentioned DC motor characteristics, thereby achieving the purpose of the present application.

[0066] For example, in the initial contact stage, one way to control the DC motor to output according to the set torque is as follows: As we know, the output torque T of the DC motor is proportional to the armature current (i.e. the real-time current) Ia, which can be expressed by the formula: T=Kt×Ia. Here Kt is called the torque constant of the motor, which is determined by the design of the motor, and the unit is usually newton-meter per ampere. Therefore, accurate control of the armature current is the key to accurate control of the torque, as long as the armature current can be accurately regulated, the output torque of the motor can be accurately controlled. Based on this principle, we can achieve this goal through current closed-loop control (also called torque control loop).

[0067] The specific operation steps are as follows: First step, set the target current: first, according to the required target torque T_ref and the torque constant Kt of the motor to calculate the target current Ia_ref, the calculation formula is Ia_ref=T_ref / Kt. The target current value calculated is used as input to the current controller.

[0068] Second step, get real-time current: next, the real-time current detection value Ia_actual of the DC motor needs to be obtained. This can be achieved with the help of a current sensor, such as a low resistance sampling resistor combined with a differential amplifier, or a Hall effect current sensor, etc., which can measure the current value flowing through the motor armature in real time.

[0069] Third step, error calculation and control signal generation: through the current controller (here taking the commonly used PI controller as an example), compare the target current Ia_ref and the real-time measured current value Ia_actual, and calculate the error I_error=Ia_ref-Ia_actual between them.

[0070] The PI controller can calculate a control signal according to this error I_error, which is usually a PWM (pulse width modulation) duty cycle command or a voltage command. Among them, the proportional term P provides fast response and reduces error as much as possible; the integral term I is used to eliminate steady-state error and ensure that the actual current can accurately track the target current.

[0071] Fourth step, power drive and current control: the power drive circuit (such as the commonly used H-bridge driver) will receive the control signal (PWM signal) from the current controller. The H-bridge driver drives the internal power switch tube (such as MOSFET field effect tube or IGBT insulated gate bipolar transistor) to apply DC power voltage to both ends of the motor armature in PWM mode. By adjusting the duty cycle of the PWM signal, the average voltage applied to the motor can be adjusted, and the control of the real-time current value can be realized.

[0072] Fifth step, closed-loop feedback: the last step is to realize closed-loop feedback, the real-time current value is continuously measured and fed back to the current controller, forming a closed-loop system. In this closed-loop system, the current controller will continuously adjust the PWM duty cycle so that the actual measured real-time current Ia_actual is as close as possible to the target current Ia_ref, thereby maintaining the set torque output.

[0073] For example, during the winding and unwinding traction phase, to achieve a linear increase in the DC motor speed while ensuring that the output torque does not exceed the preset maximum limit torque, a classic speed-current dual closed-loop cascaded control structure can be used, with a torque (current) limiter added to the output of the speed loop. The specific implementation method is as follows: First, a speed ramp generator can be used. Its function is to convert the user-defined target speed N_target (usually given as a step signal) into a ramp signal N_ref(t) that increases linearly with time. Simultaneously, the ramp slope S (in RPM / s) needs to be set. This slope S determines the magnitude of the motor's acceleration, effectively avoiding the severe impact caused by step speed commands and the resulting instantaneous high current or high torque requests. The generated N_ref(t) can then be used as the input signal for the speed controller.

[0074] Next, let's look at the speed controller. Its inputs include N_ref(t) output from the ramp generator, and the actual rotational speed N_actual fed back from a speed sensor (such as an encoder). Based on these two inputs, the speed controller outputs an unlimited torque request value I_ref_unlimited. Specifically: When N_actual is less than N_ref, it means that the motor needs to accelerate. At this time, the speed error e_n is greater than 0, and the PI controller will output a positive I_ref_unlimited to request the torque required for acceleration.

[0075] When N_actual is greater than N_ref, it means that the motor needs to decelerate. At this time, the speed error e_n is less than 0, and the PI controller outputs a negative I_ref_unlimited, which means it requests braking torque.

[0076] To ensure that the torque is not overloaded, a torque / current limiter can be introduced. The input to this limiter is the unlimited torque request value I_ref_unlimited output from the speed controller, and its key parameter is the current value I_max corresponding to the maximum allowable torque.

[0077] Determining I_max requires comprehensive consideration of factors such as the motor's rated current, driver capability, heat dissipation conditions, and mechanical strength limitations. The calculation formula is I_max = T_max / Kt. The limiter outputs the limited safe torque / current command value I_ref_limited, which will be used as the input to the current controller. The specific calculation process is as follows: If |I_ref_unlimited| is not greater than I_max, it means the request value is within the safe range, so I_ref_limited = I_ref_unlimited, and it can be passed directly.

[0078] If |I_ref_unlimited| is greater than I_max, further judgment is needed: When I_ref_unlimited is greater than 0, i.e. acceleration request, I_ref_limited = +I_max. When I_ref_unlimited is less than 0, i.e. deceleration request, I_ref_limited = -I_max (or set negative limit value -I_brake_max according to specific braking strategy).

[0079] Then look at the current controller, its input is the limiter output I_ref_limited and the actual armature current I_actual feedback through the current sensor (such as Hall sensor). The output of the current controller is the PWM duty command, with which the motor current I_actual can be accurately and quickly controlled to track I_ref_limited, and thus the precise control of the motor output torque is realized.

[0080] Finally, the power drive circuit, such as the common H-bridge driver. It receives the PWM signal output by the current controller, adjusts the average voltage Va applied to the motor by driving the H-bridge power switch tube, and finally realizes the precise control of the current.

[0081] In the whole control process, parameter acquisition is also very important. The actual speed N_actual of the motor can be measured in real time by the speed sensor (such as encoder) and fed back to the speed controller; at the same time, the actual armature current I_actual is measured in real time by the current sensor (such as Hall sensor) and fed back to the current controller, in order to realize accurate closed-loop control.

[0082] For example, the speed of a DC motor is closely related to the voltage applied to the armature, the load torque, and the back electromotive force constant of the motor. Among these factors, the key to controlling the speed is to adjust the voltage applied to the motor. However, since the load change will affect the speed, a closed-loop feedback mechanism is needed to overcome this effect. The relevant formula is: N=(Va - Ia×Ra) / Ke Where N represents the motor speed; Va is the voltage applied to the armature; Ia is the real-time current value, that is, the armature current; Ra represents the armature resistance; and Ke is the back electromotive force constant of the motor, usually in units of V / (rad / s) or V / rpm. As can be seen from the formula, the speed N is mainly affected by the applied voltage Va (because Ia x Ra is usually relatively small). But once the load changes, Ia will change, which in turn affects the speed, so closed-loop control must be used. Here, the double-closed-loop structure composed of speed closed-loop control and embedded current loop can be used, where the outer loop is the speed loop and the inner loop is the current loop (also known as the torque loop). The specific implementation steps are as follows: First, set the target speed N_ref: input the desired motor speed (target speed) N_ref into the system, and at the same time, use a speed sensor (such as an encoder, a tachometer generator, or a Hall sensor, etc.) to measure the actual speed N_actual of the motor in real time. These speed sensors can convert the rotation information of the motor into an electrical signal, so that the actual speed can be accurately obtained.

[0083] Second, use a speed controller (here, a common PI controller can be used) to compare the target speed N_ref and the actual speed N_actual, and calculate the speed error N_error = N_ref - N_actual. The PI controller will adjust the output according to this speed error to make the motor speed tend to the target value.

[0084] After that, the PI controller calculates a target current value Ia_ref_speed based on N_error. This Ia_ref_speed represents the amount of torque that the motor needs to generate to achieve acceleration or deceleration to achieve the target speed under the current speed error. It should be noted that Ia_ref_speed will be limited within the maximum current range allowed by the motor and the driver to ensure safe and stable operation of the system.

[0085] Then, the current controller (i.e., the torque control loop) receives the target current Ia_ref_speed from the speed controller, while obtaining the actual armature current Ia_actual in real time. Next, the PI controller compares Ia_ref_speed and Ia_actual to calculate the current error I_error and outputs a control signal (i.e., a PWM duty cycle command) to the power drive circuit (such as a common H-bridge driver). After receiving the PWM signal from the current controller, the power drive circuit drives the H-bridge switch tube to control the current and speed of the motor by adjusting the average voltage Va applied to the motor.

[0086] In the embodiment, the rotation speed and current signals form a double closed-loop feedback. The speed loop generates torque (current) demand according to the difference between the actual rotation speed and the target rotation speed, and the current loop accurately implements the torque demand. This structure enables the system to quickly respond to load changes. For example, when the load suddenly increases and the rotation speed drops, the speed loop will immediately require a larger torque / current to maintain the motor rotation speed stable.

[0087] In an implementation, during the high-tension cutting stage, the DC motor can be controlled to output rotation speed in a pulse mode.

[0088] Specifically, during the high-tension cutting stage, if a certain preset time elapses and the operator does not actively stop the operation, the system automatically enters the pulse mode. In this mode, the DC motor is controlled to run at a set rotation speed for a preset time, such as 0.3 to 0.5 seconds, and then is braked for another preset time, such as 50 milliseconds. In this way, the pulling of deep tissues can be effectively prevented.

[0089] In an implementation, the set rotation speed is divided into a first rotation speed and a second rotation speed, wherein the second rotation speed is smaller than the first rotation speed. Specifically, if the winding direction is parallel to the fiber direction, the set rotation speed is the first rotation speed; if the resistance encountered during winding is small, the set rotation speed is the second rotation speed.

[0090] In actual application scenarios, due to the different winding positions and surgical incision locations, there can be two winding methods, parallel to the fiber direction and perpendicular to the fiber direction. Since the winding forces required for different winding directions are different, the device involved in the present application is provided with two set rotation speeds, so that the surgical operator can flexibly select the appropriate set rotation speed according to different operating conditions.

[0091] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A medical device for the percutaneous selective detachment of fascial connective tissue, characterized in that, Includes a drive section and a winding / unwinding section; The driving unit is connected to the unwinding unit and is used to drive the unwinding unit to rotate around its axis. The roll-off section has a blunt head and a spiral roll-off groove extending along its axial direction. When the roll-off section rotates, it rolls off part of the connective tissue of the fascia through the spiral roll-off groove and collects it in the spiral roll-off groove.

2. The medical device for percutaneous selective fascia connective tissue removal as described in claim 1, characterized in that, The main body of the roll-out section is cylindrical or tapered rod-shaped. One end of the main body is integrally formed with the blunt head. The spiral roll-out groove starts from the end face of the blunt head and extends spirally along the main body axis. The length of the spiral roll-out groove ranges from 5 cm to 3 mm.

3. The medical device for percutaneous selective fascia connective tissue removal as described in claim 1, characterized in that, The end face of the blunt head is a continuous smooth curved surface without cutting function, and the radius of curvature is not less than 0.6 times the maximum diameter of the main body of the roll-off part.

4. The medical device for percutaneous selective fascia connective tissue retraction as described in any one of claims 1 to 3, characterized in that, The main body of the unwinding section is provided with a negative pressure passage. One end of the negative pressure passage is connected to the spiral unwinding groove, and the other end is used to connect to a negative pressure device.

5. The medical device for percutaneous selective fascia connective tissue removal as described in claim 4, characterized in that, The drive unit includes a power supply unit, a DC motor, and a control unit; The power supply unit is electrically connected to the DC motor and the control unit respectively, and supplies power to the DC motor and the control unit; The control unit is electrically connected to the DC motor, and controls the operation of the DC motor to make the unwinding part perform a rotation action.

6. The medical device for percutaneous selective fascia connective tissue removal as described in claim 5, characterized in that, The stall torque of the DC motor is between 10 and 60 Nm, and the control unit is used for: During the initial contact phase, the DC motor is controlled to output a set torque. During the winding and unwinding phase, the speed of the DC motor is controlled to increase linearly, and the output torque does not exceed the preset maximum limit torque. During the high-tension cutting phase, the DC motor is controlled to output at a set speed.

7. The medical device for percutaneous selective fascia connective tissue removal as described in claim 6, characterized in that, The control unit is specifically used for: Upon power-on startup, the system enters the initial contact phase, controlling the DC motor to output a set torque. Monitor the real-time current of a DC motor; If the real-time current is greater than a preset first threshold and the rate of increase of the real-time current is greater than a preset second threshold, then the winding and unwinding traction stage is entered, and the speed of the DC motor is controlled to increase linearly, and the output torque does not exceed the preset maximum limit torque.

8. The medical device for percutaneous selective fascia connective tissue removal as described in claim 7, characterized in that, The control unit is specifically used to: in the winding and unwinding traction stage, if the real-time current is greater than a preset third threshold and the fluctuation rate of the real-time current is less than a preset fourth threshold, then enter the high-tension cutting stage and control the DC motor to output at a set speed.

9. The medical device for percutaneous selective fascia connective tissue removal as described in claim 8, characterized in that, The control unit is also used to: control the DC motor to output speed in a pulse manner during the high-tension cutting stage.

10. The medical device for percutaneous selective fascia connective tissue removal as described in claim 8, characterized in that, The set rotation speed includes a first rotation speed and a second rotation speed, wherein the second rotation speed is less than the first rotation speed. If the winding direction is parallel to the fiber direction, then the set rotation speed is the first rotation speed. If the winding resistance is low, then the set rotational speed is the second rotational speed.

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