Developable suture capturing device and stitching instrument system

Abstract

The invention discloses a developable suture capturing device and a stitching instrument system.According to the developable suture capturing device, a net-shaped base body of a capturing net is made of a high polymer material, and the surface of the net-shaped base body is treated, so that a microstructure is formed on the surface of the net-shaped base body, and the surface of the net-shaped base body becomes rough; therefore, a developing agent formed by mixing polysaccharide macromolecules and iodine contrast agents can be stably sprayed and attached to the surface of the net-shaped base body, the capturing net made of non-metal materials can be clearly developed under irradiation of X-rays, and the specific position of the capturing net in the body of a patient can be determined by means of the X-rays in an operation. The surface of the developing layer attached to the surface of the net-shaped base body is also rough by forming the microstructure on the surface of the net-shaped base body, so that under the condition that liquid such as blood is adsorbed on the suture and the suture is easy to slip, the capture net can effectively clamp the suture by means of the rough surface, and the effect of grasping the suture is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surgical suture capture, in particular to a visible suture capture device and a suturing system. BACKGROUND

[0002] One of the conditions of atrial septal defect is patent foramen ovale (PFO). Among the existing treatment methods for patent foramen ovale, there are mainly two methods of occlusion and suture. In the suture operation process, since the minimally invasive surgery is adopted, the operator cannot directly visually observe the abnormal area of the heart defect without the aid of any auxiliary tool, as in the traditional open chest surgery. For the instruments entering the heart defect area, the capture net used in the suture surgery instrument needs to be developed by a developing device so as to observe the position of the capture net. Therefore, the traditional capture net is made of metal wire, but the surface of the capture net made of metal wire is relatively smooth, which has the risk of being unable to effectively capture the suture in the operation process. SUMMARY

[0003] The main purpose of the present application is to provide a visible suture capture device and a suturing system, so as to solve the problem that the capture net made of metal material cannot effectively capture the suture in the prior art.

[0004] In a first aspect, the present application provides a visible suture capture device, which comprises a capture net, the capture net has an unfolded state and a folded state, the capture net can pass through the suture when being in the unfolded state, and the capture net can clamp the suture passing through the capture net when being in the folded state.

[0005] The capture net comprises a net-shaped base body and a developing layer, the net-shaped base body is made of a high polymer material, the developing layer is attached to the surface of the net-shaped base body, the developing layer can be developed under X-ray irradiation, and the capture net is prepared by the following steps: The surface of the net-shaped base body is treated; A polysaccharide polymer and an iodine contrast agent are mixed to form a developing agent; The developing agent is sprayed to the surface of the net-shaped base body by a spraying device to form the developing layer, and the visible capture net is prepared.

[0006] Further, the treatment of the surface of the net-shaped base body comprises plasma activation treatment of the surface of the net-shaped base body under vacuum state, and / or laser treatment of the surface of the net-shaped base body by laser.

[0007] Further, the treatment of the surface of the net-shaped base body comprises placing the mesh substrate in a vacuum chamber of a plasma device; connecting the mesh substrate with an electrode disc of the plasma device by conductive glue; vacuumizing the vacuum chamber to 5-17 mTorr; plasma-activating the surface of the mesh substrate.

[0008] Further, the processing of the surface of the mesh substrate comprises plasma surface activation of the surface of the mesh substrate by radio frequency bias plasma; and / or, the processing of the surface of the mesh substrate comprises: starting the electrode disc to rotate at a constant speed; using oxygen as the plasma excitation gas source; controlling the vacuum degree in the vacuum chamber to be kept at 15 mTorr; setting the power of the plasma device to be 30 W; plasma-activating the surface of the mesh substrate for 20-60 min; Alternatively, the processing of the surface of the mesh substrate comprises: starting the electrode disc to rotate at a constant speed; using nitrogen as the plasma excitation gas source; controlling the vacuum degree in the vacuum chamber to be kept at 25 mTorr; setting the power of the plasma device to be 50 W; plasma-activating the surface of the mesh substrate for 20-60 min.

[0009] Further, the mixing of the polysaccharide polymer and the iodine-based contrast agent to form the developing agent comprises: mixing iohexol and sodium carboxymethylcellulose powder in a mass ratio of 95:5, and then preparing the developing agent with a concentration of 10%; or, mixing iohexol and soluble chitosan powder in a mass ratio of 85:15, and then preparing the developing agent with a concentration of 10%; or, mixing ioversol and hyaluronic acid powder in a mass ratio of 90:10, and then preparing the developing agent with a concentration of 5%; and / or, the polysaccharide polymer is selected from any one of soluble chitosan, sodium alginate, hyaluronic acid and sodium carboxymethylcellulose; the iodine-based contrast agent is selected from any one of iodized oil, iopromide, iohexol, iopamidol, ioversol and iodixanol.

[0010] Further, the net-shaped base is made of degradable polymer material, and the polysaccharide polymer is made of degradable polymer material. Alternatively, the net-shaped base is made of degradable polymer material, and the polysaccharide polymer is made of non-degradable polymer material. Alternatively, the net-shaped base is made of non-degradable polymer material, and the polysaccharide polymer is made of degradable polymer material. Alternatively, the net-shaped base is made of non-degradable polymer material, and the polysaccharide polymer is made of non-degradable polymer material.

[0011] In a second aspect, the application further provides a suture system, which comprises a suture main body and the above-mentioned any one of the visualizable suture catching devices, and the visualizable suture catching device is movably arranged in the suture main body. The visualizable suture catching device further comprises a first connecting tube, the catching net has opposite first and second ends, the first end is fixedly connected to the first connecting tube, and the first connecting tube and the catching net jointly form a first channel. A guide wire is movably arranged in the first channel, the guide wire comprises a first segment and a second segment, the second segment extends out of the first channel at the second end, and the maximum diameter of the part of the second segment close to the first segment is greater than the inner diameter of the first channel. Under the action of an external force, the second end can be pulled close to the first end, so that the catching net is switched from the retracted state to the expanded state.

[0012] Further, the suture system further comprises a second connecting tube, the second end is fixedly connected to the second connecting tube, the first connecting tube, the catching net and the second connecting tube jointly form the first channel, and the maximum diameter of the part of the second segment close to the first segment is greater than the inner diameter of the second connecting tube.

[0013] Further, the second connecting tube comprises a first tube and a second tube, the first tube is sleeved on the outer periphery of the second tube, a clamping space is formed between the first tube and the second tube, the second end is fixedly connected in the clamping space, and the maximum diameter of the part of the second segment close to the first segment is greater than the inner diameter of the second tube.

[0014] Further, the first section of the guide wire is configured to form a limiting portion near the second section, the limiting portion is capable of being limited with the end face of the second tube near the first end, so that the guide wire is capable of pulling the catching net from the unfolding state to the folding state when the guide wire is extended from the first channel to the second end under the action of an external force. Alternatively, the suturing device system further comprises an elastic member made of a high polymer material, the elastic member is arranged in the first channel and located outside the first section, and the elastic member is used to drive the catching net from the unfolding state to the folding state.

[0015] Further, the second section and the first section form a limiting surface at the connection position, and the limiting surface is limited at the opening of the first channel near the second end. The limiting surface is an annular plane, and the limiting surface is perpendicular to the axial direction of the guide wire. Alternatively, the limiting surface is an annular inclined surface, and the diameter of the limiting surface gradually increases from the first section to the second section. Alternatively, the limiting surface is an annular inclined surface, and the diameter of the limiting surface gradually decreases from the first section to the second section.

[0016] Further, the guide wire further comprises a third section, the second section is connected between the first section and the third section, the diameter of the third section is substantially the same as the diameter of the first section, the diameters of the first section and the third section are both smaller than the diameter of the second section, and the second section and the third section form a guide surface at the connection position, the diameter of the guide surface gradually increases from the third section to the second section, so that the third section and the second section are smoothly connected.

[0017] In the visible suture capture device of the present application, the mesh base of the capture net is made of a polymer material, and the surface of the mesh base is treated to form a microstructure and become rough, so that the developing agent formed by mixing the polysaccharide polymer and the iodine contrast agent can be stably sprayed and attached to the surface of the mesh base, thereby forming the developing layer, so that the capture net made of a non-metal material can be clearly developed under the irradiation of X-rays, so that the specific position of the capture net in the patient's body can be determined by X-rays during the operation, and by forming a microstructure on the surface of the mesh base, the surface of the developing layer attached to the surface of the mesh base is also rough, so that in the case that the liquid such as blood adsorbed on the suture becomes slippery, the capture net can effectively clamp the suture by means of the rough surface, thereby improving the effect of clamping the suture, in addition, the mesh base made of a polymer has the characteristics of being more easily deformed relative to the capture net made of a metal material, so it is easier to switch between the expanded state and the collapsed state, thereby reducing the difficulty of the operator's operation, and reducing the extrusion of the state switching to the tissue near the patient's lesion, avoiding secondary injury to the patient. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a scanning electron microscope diagram of the mesh base without plasma treatment, and the surface of the mesh base is relatively smooth and flat.

[0019] Figure 2 It is a scanning electron microscope diagram of the mesh base in an embodiment disclosed by the present application, and the surface of the mesh base has a microstructure of microns, which helps the stable attachment of the developing layer.

[0020] Figure 3 It is a contrast imaging diagram of the capture net without plasma treatment, and the imaging of the capture net is almost invisible.

[0021] Figure 4 It is a contrast imaging diagram of the capture net in an embodiment disclosed by the present application, and the imaging of the capture net is clearly visible.

[0022] Figure 5 It is an XPS spectrum of the mesh base without plasma treatment.

[0023] Figure 6 It is an XPS spectrum of the mesh base treated by plasma for 30 minutes in an embodiment of the present application, compared with Figure 5 The proportion of polar functional groups containing carbon-oxygen single bond and carbon-oxygen double bond is significantly improved, indicating that the active groups of the mesh base after treatment are significantly increased.

[0024] Figure 7 This is a schematic diagram of contrast imaging of the capture net near the lesion (patent foramen ovale) in one embodiment of this application.

[0025] Figure 8 This is a schematic diagram of a stitching system in one embodiment of the present application, showing the capture net in a retracted state with a portion extending out of the second channel.

[0026] Figure 9 This is a schematic diagram of a stitching system in one embodiment of the present application, showing the capture net in a retracted state and fully extended from the second channel.

[0027] Figure 10 This is a schematic diagram of a stitching system in one embodiment of the present application, showing the capture net in an unfolded state with the second channel fully extended.

[0028] Figure 11 This is a schematic diagram of the cooperation between the capture net and the guide wire in one embodiment of this application.

[0029] Figure 12 This is a schematic diagram of the cooperation between the capture net and the guide wire in another embodiment disclosed in this application.

[0030] Figure 13 This is a schematic diagram of a guidewire in one embodiment of this application.

[0031] Figure 14 This is a schematic diagram illustrating the cooperation of the capture net, the second connecting pipe, and the first connecting pipe in one embodiment of this application.

[0032] Figure 15 This is a projection view of the capture net, the first connecting tube, and the guide wire along the direction from the second end to the first end in one embodiment of this application.

[0033] Figure 16 This is a partial structural diagram of a suture system in one embodiment of the present application, in which a puncture needle passes through the interatrial septum and a capture net.

[0034] Figure 17 This is a partial structural diagram of a suture system in one embodiment of the present application, in which the suture extends out of the puncture needle.

[0035] Figure 18 This is a partial structural diagram of the suture system in one embodiment of the present application, showing the puncture needle retracting into the needle insertion chamber.

[0036] Figure 19 This is a partial structural diagram of the stitching system in one embodiment of this application, in which the capture net is in a retracted state.

[0037] Figure 20This is a schematic diagram showing the atrial septal defect after it has been sutured.

[0038] The above figures include the following reference numerals: The capture net 11 includes a first end 111, a second end 112, a first connecting tube 12, a guide wire 13, a first section 131, a second section 132, a limiting surface 1321, a guiding surface 1322, a third section 133, a limiting part 134, a connecting rod part 1341, a hook part 1342, a first channel 14, a second connecting tube 15, a first tube 151, a second tube 152, a third connecting tube 21, a multi-lumen tube assembly 22, a needle insertion cavity 221, a positioning assembly 23, a positioning rod 231, a puncture needle 30, and a suture 40. Detailed Implementation

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0042] Please see Figures 1-10As shown, in a first aspect, this application provides a visible suture capture device, the visible suture capture device including a capture net 11, the capture net 11 having an unfolded state and a retracted state, the capture net 11 allowing sutures 40 to pass through when in the unfolded state, and the capture net 11 clamping the sutures 40 passing through the capture net 11 when in the retracted state.

[0043] The capture net 11 includes a mesh substrate and a developing layer. The mesh substrate is made of a polymer material, and the developing layer is attached to the surface of the mesh substrate. The developing layer can be developed under X-ray irradiation. The capture net 11 is prepared by the following steps: The surface of the mesh substrate is treated; Polysaccharide polymers are mixed with iodine-based contrast agents to form a contrast agent; The developing agent is sprayed onto the surface of the mesh substrate using a spraying device to form the developing layer, thereby preparing the developable capture net 11.

[0044] By using a polymer material to make the mesh substrate of the capture net 11, and by treating the surface of the mesh substrate to form a microstructure and roughen the surface, the contrast agent formed by the mixture of the polysaccharide polymer and the iodine contrast agent can be stably sprayed and adhered to the surface of the mesh substrate, thereby forming the contrast layer. Therefore, the capture net 11, made of non-metallic material, can be clearly visualized under X-ray irradiation, so that the specific location of the capture net 11 in the patient's body can be determined by X-ray during surgery. Furthermore, by forming a microstructure on the surface of the mesh substrate, the surface of the contrast layer attached to the mesh substrate is also rough. Therefore, when the suture 40 is slippery due to the adsorption of blood or other liquids, the capture net 11 can effectively clamp the suture 40 with the help of the rough surface, thereby improving the gripping effect of the suture 40.

[0045] In addition, the polymer-based mesh matrix is ​​more prone to yielding and deformation than the metal mesh 11, making it easier to switch between the unfolded and retracted states. This reduces the difficulty of the operator's operation and the risk of the mesh 11 compressing the tissues near the patient's lesion during the state switching process, thereby reducing secondary damage to the patient.

[0046] Furthermore, the above-mentioned preparation process is simple and fast, and the developing function of the capture net 11 can be achieved without the use of adhesives. The mesh substrate made of polymer materials can be quickly prepared by injection molding and has a stable structure. The developer can be further coated to enhance the adhesion of the developer to the surface of the mesh substrate, thereby enhancing the adhesion of the developing layer. This avoids the risk of the developing layer falling off during the switching between the retracted and extended states of the capture net 11, and also extends the service life of the capture net 11.

[0047] In the embodiments of this application, the treatment of the surface of the mesh substrate includes: performing plasma activation treatment on the surface of the mesh substrate under vacuum. By performing plasma activation treatment on the surface of the mesh substrate under vacuum, the surface of the mesh substrate can be thoroughly cleaned, and the proportion of polar groups on the surface of the mesh substrate can be increased. This allows the polar groups to form hydrogen bonds, dipole interactions, and electrostatic interactions between the iodine contrast agent and the polysaccharide polymer, significantly improving their compatibility and system stability. At the same time, the polar groups can enhance the wetting, spreading, and adsorption capacity of the contrast solution on the surface of biological tissues, improve the adhesion strength and retention time of the contrast solution on the surface of tissues or materials, make the contrast layer evenly distributed and less prone to loss, which is conducive to achieving clear and stable imaging.

[0048] Please see Figures 1-7 As shown in the embodiments of this application, the surface treatment of the mesh matrix includes: laser treatment of the surface of the mesh matrix by laser, thereby constructing a micron-nano-scale multi-scale composite rough structure on the surface of the mesh matrix, forming densely distributed micropores, pits, grooves, protrusions and melt-recast morphology on the surface, significantly increasing the actual specific surface area of ​​the mesh matrix; at the same time, the thermal and photochemical effects of the laser can cause polymer chains to break, oxidize and carbonize, and introduce hydroxyl, carboxyl, carbonyl and polar functional groups containing carbon-oxygen single bonds in situ on the surface of the mesh matrix, significantly improving the polarity and hydrophilicity of the surface of the mesh matrix.

[0049] The synergistic effect of the aforementioned surface structure and chemical properties provides physical anchoring and mechanical interlocking for the developing layer, enabling the developer to adhere more firmly to the surface of the mesh substrate. On the other hand, it significantly increases the effective contact area between the developer and the substrate, and strengthens the interfacial bonding force through hydrogen bonding, dipole-dipole interactions, and electrostatic adsorption. This significantly improves the adhesion, uniformity, and erosion resistance of the developer on the surface of the mesh substrate, effectively addressing problems such as developer detachment, uneven distribution, and insufficient adhesion.

[0050] In the embodiments of this application, the surface of the mesh substrate can be laser-treated first, and then plasma-activated in a vacuum state, so that the developing layer is more stably and uniformly attached to the surface of the mesh substrate.

[0051] In embodiments of this application, the treatment of the surface of the mesh substrate includes: The mesh matrix is ​​placed inside the vacuum chamber of the plasma device; The mesh substrate is connected to the electrode disk of the plasma device using conductive adhesive. The vacuum chamber was evacuated to 5-17 mTorr; The surface of the mesh substrate is subjected to plasma activation treatment.

[0052] By placing the mesh substrate in the vacuum chamber of the plasma processing device and fixing the mesh substrate to the electrode disk of the plasma device with conductive adhesive, it is ensured that the substrate is stable in position, does not shift or tilt in the vacuum and gas flow environment, so that the plasma can act uniformly on the surface of the substrate.

[0053] The vacuum chamber was then evacuated to achieve a vacuum level of 5–17 mTorr, in order to meet the conditions for stable plasma excitation.

[0054] After reaching the target vacuum level, the power supply of the plasma device is turned on to perform plasma activation treatment on the surface of the mesh substrate. Through high-energy particle bombardment, etching and oxidation, polar groups such as hydroxyl, carboxyl and carbonyl groups are introduced into the surface of the mesh substrate to increase the surface energy, thereby enhancing the adhesion between the developing layer and the mesh substrate.

[0055] In the embodiments of this application, the processing of the surface of the mesh substrate includes: performing plasma surface activation treatment on the surface of the mesh substrate by radio frequency bias plasma, thereby enabling deep etching of the surface of the mesh substrate. By controlling the parameters of the radio frequency bias, the etching depth and surface morphology can be precisely controlled, thereby improving the surface energy of the surface of the mesh substrate and thus strengthening the adhesion between the developing layer and the mesh substrate.

[0056] In the embodiments of this application, the capture net is prepared through the following steps: The mesh substrate was attached to the electrode disk using conductive adhesive and then placed into the plasma device. A vacuum of 5-17 mTorr was then evacuated.

[0057] Parameters were set in the CNC system, and the electrode disk was started to rotate, ensuring uniform etching so that the developer could adhere evenly to the surface of the mesh substrate, thus enabling stable and uniform development under X-ray irradiation. Oxygen was used as the plasma excitation gas source. The gas flow rate was adjusted, the gas pressure was adjusted to 15 mTorr, the power was set to 30 W, and the etching time was 20-60 min. Subsequently, the gas pressure was restored, and the electrode disk and the mesh substrate were removed.

[0058] Iohexol and sodium carboxymethyl cellulose powder were mixed at a mass ratio of 95:5 to prepare a developer with a concentration of 10%.

[0059] A contrast agent spraying solution is added to the spray gun container, and the treated mesh substrate surface is sprayed through the spray gun to obtain the capture net 11 with the developing layer.

[0060] The etching time mentioned above can be 20 min or 60 min, or any time between 20 min and 60 min, for example, it can also be 25 min, 30 min, 40 min, 52 min, 55 min, etc., which will not be listed here.

[0061] In the embodiments of this application, the capture net 11 is prepared through the following steps: The mesh substrate was attached to the electrode disk using conductive adhesive and then placed into the plasma device. A vacuum of 5-17 mTorr was then evacuated.

[0062] Parameters were set in the CNC system, and the electrode disk was started to rotate, ensuring uniform etching so that the developer could adhere evenly to the surface of the mesh substrate, thus enabling stable and uniform development under X-ray irradiation. Oxygen was used as the plasma excitation gas source. The gas flow rate was adjusted, the gas pressure was adjusted to 15 mTorr, the power was set to 30 W, and the etching time was 20-60 min. Subsequently, the gas pressure was restored, and the electrode disk and the mesh substrate were removed.

[0063] Iohexol and soluble chitosan powder were mixed at a mass ratio of 85:15 to prepare a 10% developer.

[0064] A contrast agent spraying solution is added to the spray gun container, and the treated mesh substrate surface is sprayed through the spray gun to obtain the capture net 11 with the developing layer.

[0065] The etching time mentioned above can be 20 min or 60 min, or any time between 20 min and 60 min, for example, it can also be 25 min, 30 min, 40 min, 52 min, 55 min, etc., which will not be listed here.

[0066] In the embodiments of this application, the capture net 11 is prepared through the following steps: The mesh substrate was attached to the electrode disk using conductive adhesive and then placed into the plasma device. A vacuum of 5-17 mTorr was then evacuated.

[0067] Parameters were set in the CNC system, and the electrode disk was started to rotate, ensuring uniform etching so that the developer could adhere evenly to the surface of the mesh substrate, thus enabling stable and uniform development under X-ray irradiation. Nitrogen was used as the plasma excitation gas source. The gas flow rate was adjusted, the gas pressure was set to 25 mTorr, the power was set to 50 W, and the etching time was 20-60 min. Subsequently, the gas pressure was restored, and the electrode disk and the mesh substrate were removed.

[0068] Iodophorol and hyaluronic acid powder are mixed at a mass ratio of 90:10 to prepare a developer with a concentration of 5%.

[0069] A contrast agent spraying solution is added to the spray gun container, and the treated mesh substrate surface is sprayed through the spray gun to obtain the capture net 11 with the developing layer.

[0070] The etching time mentioned above can be 20 min or 60 min, or any time between 20 min and 60 min, for example, it can also be 25 min, 30 min, 40 min, 52 min, 55 min, etc., which will not be listed here.

[0071] In the embodiments of this application, the polysaccharide polymer is selected from any one of soluble chitosan, sodium alginate, hyaluronic acid and sodium carboxymethyl cellulose, which can further enhance the adhesion of iodine-based contrast agents to the material surface and can form a gel to make the contrast agent more stably adhered to the surface of the mesh substrate, thereby making the imaging layer stably adhered to the surface of the mesh substrate.

[0072] In the embodiments of this application, the iodine-based contrast agent is selected from any one of iodized oil, iopromide, iohexol, iopamidol, iodofol, and iodixanol. Therefore, even if there is a contrast agent remaining in the patient's body during the operation, it can be excreted through kidney metabolism.

[0073] In the embodiments of this application, the mesh matrix is ​​made of a biodegradable polymer material, and the polysaccharide polymer is made of a biodegradable polymer material. Therefore, the capture net 11 can be completely degraded.

[0074] In the embodiments of this application, the mesh matrix is ​​made of a biodegradable polymer material, and the polysaccharide polymer is made of a non-biodegradable polymer material. Therefore, the mesh matrix is ​​biodegradable, and the polysaccharide polymer is non-biodegradable, so the capture net 11 can be partially degraded.

[0075] In the embodiments of this application, the mesh matrix is ​​made of a non-degradable polymer material, and the polysaccharide polymer is made of a degradable polymer material. Therefore, the mesh matrix is ​​not degradable, while the polysaccharide polymer is degradable. Thus, the capture net 11 can be partially degraded.

[0076] In the embodiments of this application, the mesh matrix is ​​made of a non-degradable polymer material, and the polysaccharide polymer is also made of a non-degradable polymer material. Therefore, the capture net 11 is not degradable.

[0077] In the embodiments of this application, the developer can be applied to the mesh substrate by multiple sprayings. That is, after each spraying of the developer, it is necessary to wait for the currently sprayed developer to dry before the next spraying.

[0078] In the embodiments of this application, the developer is sprayed 1-6 times, that is, the developer can be sprayed 1 time, 2 times, 3 times, 4 times, 5 times, or 6 times, and no specific number is specified here.

[0079] In the embodiments of this application, when the developer is sprayed 6 times, the content of iodine-based contrast agent in the developing layer is the highest. When the developer is sprayed more than 6 times, there may be a phenomenon of developer shedding.

[0080] In the embodiments of this application, the spraying time for each application is 5S-20S. That is to say, the spraying time for each application can be a fixed 5S, 8S, 10S, 12S, 15S, 17S, or 20S. Alternatively, the spraying time for some applications can be the same, or the spraying time for each application can be different. No specific limitation is made here.

[0081] Please refer to the patent "A Device for Grabbing Sutures" with publication number "CN119074090B". This patent discloses that existing capture nets are made of metal so that they can be visualized in vivo when exposed to X-rays. Also, the patent with publication number "CN119074090B" contains... Figure 3The schematic diagram of the planar structure of the capture net shows that the connector in the distal structure of the capture net is a blind-end fixed structure and does not have the first channel mentioned in this application. Also, please refer to the patent application with publication number CN119235384A, "Integrated Locking and Cutting Device, Thread Hooking Device and Locking and Cutting Integrated System for Medical Sutures," which discloses the locking and cutting process and operation of medical sutures, and specifically discloses how the thread fixing component is squeezed and locks the passing suture.

[0082] Because the guidewire in the existing suture system cannot be pre-installed with the capture net on the suture body, the surgeon must first pass the guidewire through the foramen ovale from the right atrium into the left atrium during the existing patent foramen ovale closure surgery procedure. Then, the sheath enters the right atrium along the guidewire and approaches the interatrial septum. Next, the guidewire is withdrawn, the capture net is inserted into the left atrium and unfolded, the puncture needle is pushed to puncture the defect tissue, the suture is pushed out of the puncture needle, the capture net is then gathered to capture the passed suture, the suture is pulled out of the body, and the locking and cutting integrated device is used to knot and cut the excess suture. Therefore, the procedure is cumbersome for the surgeon when operating the existing suture system, increasing the operation time and surgical risks.

[0083] In addition, during the process of retracting the capture net, it is necessary to pull the capture net from the unfolded state toward the proximal end into the containment tube. The containment tube is used to limit the capture net so that it can switch from the unfolded state to the retracted state. However, during this process, there is a risk of tissue being trapped in the gap between the capture net and the containment tube, as well as the problem of difficulty in retracting the capture net.

[0084] Please see Figures 8-13 As shown, in a second aspect, this application also provides a suture system, the suture system including the radiopaque suture capture device and a suture body, the radiopaque suture capture device being movably inserted through the suture body, and the radiopaque suture capture device including the capture net 11, the first connecting tube 12, and the guide wire 13. The capture net 11 has a first end 111 and a second end 112 opposite to each other. The first end 111 is fixedly connected to the first connecting tube 12, and the first connecting tube 12 and the capture net 11 together form a first channel 14; the guide wire 13 is movably inserted through the first channel 14, the guide wire 13 including a first segment 131 and a second segment 132, the second segment 132 extending out of the first channel 14 from the second end 112, and the maximum diameter of the portion of the second segment 132 near the first segment 131 is greater than the inner diameter of the first channel 14, so that the second segment 132 will not retract into the first channel 14.

[0085] Further, please refer to Figures 10-12 As shown, the capture net 11 has a retracted state and an extended state. Under the action of external force, the guide wire 13 can pull the second end 112 closer to the first end 111, so that the capture net 11 switches from the retracted state to the extended state. If the guide wire 13 does not apply force to the second end 112, or if the force applied by the guide wire 13 to the second end 112 is less than the force required to drive the second end 112 closer to the first end 111, the capture net 11 will remain in the retracted state.

[0086] In the embodiments of this application, the first channel 14 is formed by setting the first connecting pipe 12 and the capture net 11 together, and the guide wire 13 is movably passed through the first channel 14. The second segment 132 of the guide wire 13 is set to extend out of the first channel 14 at the second end 112, and the maximum diameter of the part of the second segment 132 near the first segment 131 is greater than the inner diameter of the first channel 14, so that the second segment 132 is always limited to the outside of the second end 112 of the capture net 11 away from the first connecting pipe 12. Therefore, under external force, the guide wire 13 can pull the second end 112 closer to the first end 111, so that the capturing net 11 switches from the retracted state to the unfolded state, thereby enabling the capturing net 11 to grasp the suture 40. Furthermore, when the capturing net 11 is not subjected to external force or the external force is small, the capturing net 11 will remain in the retracted state. Therefore, this application not only pre-installs the capturing net 11 and the guide wire 13 in the suture system to shorten surgical time and improve surgical and operational efficiency, but also cleverly utilizes the guide wire 13 in conjunction with the first connecting tube 12 to achieve the transition of the capturing net 11 between the retracted and unfolded states. This design allows the capture net 11 to switch from the unfolded state to the retracted state under the action of the guide wire 13. This avoids the need for a dedicated pipe to transport the capture net 11 to achieve the switch from the unfolded state to the retracted state. Furthermore, the guide wire 13 cleverly guides the capture net 11, allowing it to smoothly enter the left atrium. Therefore, it avoids the risk of tissue being accidentally caught during the switch from the unfolded state to the retracted state, as well as the risk of difficulty in retracting the capture net 11. It also reduces the need for a dedicated pipe, thereby simplifying the overall structure and assembly steps of the suture system.

[0087] In existing technology, when a metal capture net switches from an unfolded state to a retracted state, a push-pull mechanism is used to push the connecting wires inward, i.e., push the connecting wires away from the push-pull mechanism. This allows the capture net to change from an unfolded state to a retracted state under the limiting action of the net's storage tube. Therefore, the existing net storage tube is also made of a rigid material. Consequently, in this existing technology, during the switch from an unfolded state to a retracted state, the seams passing through the capture net are subjected to rigid friction between the capture net (metal) and the net storage tube (rigid material) at their open ends, leading to wear or breakage of the seams. There are several risks involved. If the suture breaks, the surgery will fail immediately, requiring a repeat suturing procedure, which increases both cost and risk. If the suture wears down, it may break during the subsequent tightening process due to pressure from the locking pins, leading to further failure and requiring a repeat suturing procedure, again increasing cost and risk. Even if the locking pins do not break the worn suture, there is still a risk that the worn suture may break due to tissue movement near the foramen ovale during the healing process after surgery (at the patent foramen ovale), caused by the continuous beating of the heart, resulting in surgical failure.

[0088] Compared to the risk of surgical failure in the prior art, this application uses a non-metallic capture net 11 and pre-switches the capture net 11 from the unfolded state to the retracted state before it enters the first channel 14. This effectively avoids the problem of suture breakage or wear caused by friction between the capture net 11 and the net housing tube, thereby further improving the success rate of the surgery.

[0089] In the embodiments of this application, the first end 111 may be fixedly connected to the inner side wall of the first connecting pipe 12, or fixedly connected to the outer side wall of the first connecting pipe 12, or fixedly connected to the end face of the first connecting pipe 12, without being specifically limited here.

[0090] In the embodiments of this application, please refer to Figures 13-15 As shown, the stitching system also includes a second connecting tube 15. The second end 112 is fixedly connected to the second connecting tube 15. By setting the second connecting tube 15, the two ends of each of the capture wires constituting the capture net 11 can be fixedly connected to the first connecting tube 12 and the second connecting tube 15 respectively, so that the first connecting tube 12, the capture net 11 and the second connecting tube 15 together form the first channel 14.

[0091] Furthermore, the maximum diameter of the portion of the second segment 132 closest to the first segment 131 is greater than the inner diameter of the second connecting tube 15. Therefore, during the process of the guide wire 13 cooperating with the second connecting tube 15 to switch the capture net 11 from the retracted state to the unfolded state under the action of external force, the second connecting tube 15 will limit the second segment 132 so that the guide wire 13 can pull the second end 112 closer to the first end 111.

[0092] In the embodiments of this application, the second connecting tube 15 is a single tube with uniform specifications, and each of the capture wires corresponding to the second end 112 of the capture net 11 is fixedly connected to the outer periphery of the second connecting tube 15 so that the guide wire 13 can smoothly pass through the inside of the second connecting tube 15.

[0093] It is understood that each of the capture wires corresponding to the second end 112 of the capture net 11 can also be fixedly connected to the inner side or end face of the second connecting tube 15, without specific limitation here.

[0094] In the embodiments of this application, please refer to Figures 12-15 As shown, the second connecting tube 15 includes a first tube 151 and a second tube 152. The first tube 151 is sleeved on the outer periphery of the second tube 152, and a clamping space is formed between the first tube 151 and the second tube 152. The second end 112 is fixedly connected in the clamping space. The maximum diameter of the portion of the second segment 132 near the first segment 131 is greater than the inner diameter of the second tube 152, thereby using the second tube 152 to limit the guide wire 13, so that the guide wire 13 can cooperate with the first connecting tube 12 and the second connecting tube 15 to switch the capture net 11 from the retracted state to the unfolded state.

[0095] In an embodiment of this application, the first segment 131 of the guide wire 13 is configured with a limiting part 134 near the second segment 132. The limiting part 134 can limit each other with the end face of the second tube 152 near the first end 111, so that when the guide wire 13 extends from the second end 112 into the first channel 14 under the action of external force, it pulls the capture net 11 from the unfolded state to the retracted state.

[0096] By setting the limiting part 134 and the second tube 152 to limit each other, the capture net 11 can be quickly switched from the unfolded state to the retracted state by the pull of the guide wire 13, thereby ensuring that the capture net 11 can be completely reset to the retracted state. In this way, the capture net 11 in the retracted state can effectively clamp the passing suture 40 and pull the suture 40 out of the patient's body, which is convenient for subsequent knotting of the suture 40.

[0097] In an embodiment of this application, the limiting part 134 may be a hook, which includes a connecting rod and a hook. The connecting rod is connected to the hook and the rod is connected to the first segment 131. When it is necessary to restore the capture net 11 to the folded state, the guide wire 13 is pushed to the distal end so that the second tube 152 moves away from the first end 111, thereby completely restoring the capture net 11 to the folded state, which facilitates the withdrawal of the capture net 11 from the patient's body.

[0098] In the embodiments of this application, the limiting portion 134 may also be a limiting protrusion, which is located outside the first segment 131 and protrudes outward along the radial direction of the first segment 131.

[0099] In embodiments of this application, the stitching system further includes an elastic element made of a polymer material, therefore, the elastic element itself does not have a imaging function. The elastic element is disposed within the first channel 14 and located outside the first segment 131, and the elastic element is used to drive the capture net 11 to switch from the unfolded state to the retracted state.

[0100] The elastic element is always in a state of elastic compression within the elastic deformation range. When the capture net 11 is in the unfolded state, the elastic element is in the maximum compression state within the elastic deformation range. When the capture net 11 is in the retracted state, the elastic element is in the minimum compression state within the elastic deformation range.

[0101] By setting the elastic element, the capture net 11 can switch from the unfolded state to the retracted state more quickly and efficiently, and ensure that the capture net 11 can be completely reset to the retracted state, thereby ensuring the clamping effect of the capture net 11 on the passing sewing thread 40, and further preventing the passing sewing thread 40 from slipping and loosening.

[0102] In the embodiments of this application, the two ends of the elastic member abut against the two opposite end faces of the first tube 151 and the first connecting tube 12, so that the elastic member can drive the capture net 11 from the unfolded state to the retracted state by elastically squeezing the first tube 151 and the first connecting tube 12.

[0103] In the embodiments of this application, please refer to Figure 13 As shown, a limiting surface 1321 is formed at the connection between the second segment 132 and the first segment 131. The limiting surface 1321 is limited at the opening of the first channel 14 near the second end 112, so that when the guide wire 13 retracts toward the first channel 14 under the action of external force, it can drive the capture net 11 to switch from the retracted state to the unfolded state and remain in the unfolded state.

[0104] In the embodiments of this application, the limiting surface 1321 is an annular plane, and the limiting surface 1321 is perpendicular to the axial direction of the guide wire 13; or, the limiting surface 1321 is an annular inclined surface, and the diameter of the limiting surface 1321 gradually increases from the first segment 131 toward the second segment 132; or, the limiting surface 1321 is an annular inclined surface, and the diameter of the limiting surface 1321 gradually decreases from the first segment 131 toward the second segment 132. By setting the limiting surface 1321 to an annular plane or an annular inclined surface, the guide wire 13 can stably abut against the second connecting pipe 15, thereby enabling the guide wire 13 to cooperate with the first connecting pipe 12 and the second connecting pipe 15 to switch the capture net 11 from the retracted state to the unfolded state.

[0105] In the embodiments of this application, please refer to Figure 13 As shown, the guidewire 13 also includes a third segment 133. The second segment 132 is connected between the first segment 131 and the third segment 133. Therefore, the first segment 131, the second segment 132, and the third segment 133 are arranged sequentially. The diameter of the third segment 133 is basically the same as the diameter of the first segment 131, and the diameters of both the first segment 131 and the third segment 133 are smaller than the diameter of the second segment 132, thereby allowing the third segment 133 to easily bend and pass through to smoothly establish a treatment path.

[0106] Please see Figures 16-19As shown in the embodiment of this application, a guide surface 1322 is formed at the connection between the second segment 132 and the third segment 133. The guide surface 1322 can smoothly guide the guide wire 13 through the atrial septal defect, and when the limiting surface 1321 abuts against the second connecting tube 15, the guide surface 1322 can also simultaneously guide the second connecting tube 15, the capture net 11 and the first connecting tube 12 smoothly from the right atrium through the atrial septal defect into the left atrium, thereby avoiding the end face of the second connecting tube 15 connected to the capture net 11 from pushing against the tissue near the defect when passing through the defect.

[0107] In embodiments of this application, the diameter of the guide surface 1322 gradually increases from the third segment 133 toward the second segment 132, so that the third segment 133 and the second segment 132 are smoothly connected. The guide surface 1322 can be an annular inclined surface or a spherical surface; no specific limitation is made here.

[0108] In embodiments of this application, the suture body includes a first operating end, a second operating end, a third operating end, a third connecting tube 21, a multi-lumen tube assembly 22, and a positioning assembly 23.

[0109] The end of the first connecting pipe 12 away from the capture net 11 is connected to the first operating end. By operating the first operating end, the first connecting pipe 12 can be controlled to move within the second channel, so that the capture net 11 extends out of the second channel or retracts into the second channel.

[0110] The second operating end is close to the first operating end, and the third connecting pipe 21 is connected to the second operating end. The third connecting pipe 21 is used to accommodate the capture net 11, the first connecting pipe 12, the multi-cavity tube assembly 22, and the positioning assembly 23 to protect the capture net 11, the first connecting pipe 12, the multi-cavity tube assembly 22, and the positioning assembly 23.

[0111] The third operating end is close to the first operating end. The multi-lumen tube assembly 22 is connected to the third operating end. The multi-lumen tube assembly 22 is inserted into the third connecting tube 21. The multi-lumen tube assembly 22 is configured to form the second channel and a plurality of needle-piercing chambers 221. The capture net 11 and the first connecting tube 12 are movably inserted into the second channel. Each needle-piercing chamber 221 is used for a puncture needle 30 to pass through, and each puncture needle 30 is used for a suture 40 to pass through.

[0112] Please see Figures 16-19As shown, when the capture net 11 is in the unfolded state and close to the atrial septum in the left atrium, the puncture needles 30, which are inserted into each of the needle insertion cavities 221, will extend obliquely outward from the multi-lumen tube assembly 22 and pass through the atrial septal tissue near the atrial septal defect and the capture net 11 in sequence. Then, the sutures 40 are pushed out from the puncture needles 30, so that the sutures 40 pass through the capture net 11. Then, each of the puncture needles 30 is withdrawn into the corresponding needle insertion cavity 221. Then, the capture net 11 is switched to the closed state until the capture net 11 and the first connecting tube 12 exit the second channel, thereby leading each of the sutures 40 after passing through the tissue out of the patient's body. Then, the sutures 40 are locked and excess sutures 40 are cut off by the suture locking and cutting device, thereby completing the operation.

[0113] In embodiments of this application, the multi-lumen tube assembly 22 is provided with at least two (preferably four) needle insertion lumens 221, and each needle insertion lumen 221 is evenly distributed so that each puncture needle 30 can evenly pass through the atrial septum tissue near the corresponding defect.

[0114] The positioning component 23 includes multiple positioning rods 231, each of which is disposed between the multi-cavity tube assembly 22 and the third connecting tube 21. The positioning component 23 has a first state and a second state. When the positioning component 23 is in the first state, each of the positioning rods 231 extends out of the third connecting tube 21 and extends radially along the third connecting tube 21. When the positioning component 23 is in the second state, each of the positioning rods 231 is received inside the third connecting tube 21 so that the multi-cavity tube assembly 22 and the positioning component 23 can move synchronously within the sheath.

[0115] Please see Figure 20 As shown in the embodiments of this application, the suture system further includes a suture locking and cutting device, which is used to lock and cut off excess sutures 40 after passing through the atrial septum tissue near the defect.

[0116] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0117] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0118] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A visible suture capture device, characterized in that, The device includes a capture net having an extended state and a retracted state. When the capture net is in the extended state, it allows sewing threads to pass through, and when the capture net is in the retracted state, it can clamp the sewing threads that have passed through it. The capture net comprises a mesh substrate and a developing layer. The mesh substrate is made of a polymer material, and the developing layer is attached to the surface of the mesh substrate. The developing layer is visible under X-ray irradiation. The capture net is prepared by the following steps: The surface of the mesh substrate is treated; Polysaccharide polymers are mixed with iodine-based contrast agents to form a contrast agent; The developing agent is sprayed onto the surface of the mesh substrate using a spraying device to form the developing layer, thereby preparing the developable capture net.

2. The visible suture capture device according to claim 1, characterized in that, The treatment of the surface of the mesh substrate includes: performing plasma activation treatment on the surface of the mesh substrate under vacuum conditions, and / or performing laser treatment on the surface of the mesh substrate.

3. The visible suture capture device according to claim 1, characterized in that, The surface treatment of the mesh substrate includes: The mesh matrix is ​​placed inside the vacuum chamber of the plasma device; The mesh substrate is connected to the electrode disk of the plasma device using conductive adhesive. The vacuum chamber was evacuated to 5-17 mTorr; The surface of the mesh substrate is subjected to plasma activation treatment.

4. The visible suture capture device according to claim 3, characterized in that, The process of treating the surface of the mesh substrate includes: performing plasma surface activation treatment on the surface of the mesh substrate using radio frequency bias plasma; And / or, the treatment of the surface of the mesh substrate includes: The electrode disk is started to rotate at a constant speed; Oxygen is used as the plasma excitation gas source; The vacuum level inside the vacuum chamber is maintained at 15 mTorr; The power of the plasma device is set to 30W; The surface of the mesh substrate is subjected to plasma activation treatment for 20-60 minutes; Alternatively, the treatment of the surface of the mesh substrate may include: The electrode disk is started to rotate at a constant speed; Nitrogen gas was used as the plasma excitation gas source. The vacuum level inside the vacuum chamber is maintained at 25 mTorr; The power of the plasma device is set to 50W; The surface of the mesh substrate is subjected to plasma activation treatment for 20-60 minutes.

5. The visible suture capture device according to claim 1, characterized in that, The method of mixing polysaccharide polymers with iodine-based contrast agents to form a contrast agent includes: Iohexol and sodium carboxymethyl cellulose powder were mixed at a mass ratio of 95:5 to prepare a developer with a concentration of 10%. Alternatively, the developer can be prepared by mixing iohexol and soluble chitosan powder at a mass ratio of 85:15 to a concentration of 10%. Alternatively, the developer can be prepared by mixing iodofol and hyaluronic acid powder at a mass ratio of 90:10, resulting in a concentration of 5%. And / or, the polysaccharide polymer is selected from any one of soluble chitosan, sodium alginate, hyaluronic acid and sodium carboxymethyl cellulose; The iodine-based contrast agent is selected from any one of iodized oil, iopromide, iohexol, iopamidol, iofluoxetine, and iodixanol.

6. The visible suture capture device according to claim 1, characterized in that, The network matrix is ​​made of a biodegradable polymer material, and the polysaccharide polymer is also made of a biodegradable polymer material. Alternatively, the network matrix may be made of a biodegradable polymer material, and the polysaccharide polymer may be made of a non-biodegradable polymer material. Alternatively, the network matrix may be made of a non-degradable polymer material, and the polysaccharide polymer may be made of a degradable polymer material. Alternatively, the network matrix may be made of a non-degradable polymer material, and the polysaccharide polymer may be made of a non-degradable polymer material.

7. A suture system, characterized in that, The suture system includes a suture body and a radiopaque suture-catching device as described in any one of claims 1-6, wherein the radiopaque suture-catching device is movably disposed within the suture body; The visible suture capture device further includes a first connecting tube, and the capture net has a first end and a second end opposite to each other. The first end is fixedly connected to the first connecting tube, and the first connecting tube and the capture net together form a first channel. as well as A guidewire, which is movably inserted through the first channel, includes a first segment and a second segment, the second segment extending out of the first channel at its second end, and the maximum diameter of the portion of the second segment near the first segment is greater than the inner diameter of the first channel; The guide wire can be pulled closer to the first end under the action of external force, so that the capture net can switch from the retracted state to the unfolded state.

8. The suture system according to claim 7, characterized in that, The stitching system also includes a second connecting tube, with the second end fixedly connected to the second connecting tube. The first connecting tube, the capture net, and the second connecting tube together form the first channel. The maximum diameter of the second segment near the first segment is greater than the inner diameter of the second connecting tube.

9. The suture system according to claim 8, characterized in that, The second connecting tube includes a first tube and a second tube. The first tube is sleeved on the outer periphery of the second tube, and a clamping space is formed between the first tube and the second tube. The second end is fixedly connected in the clamping space, and the maximum diameter of the portion of the second section near the first section is greater than the inner diameter of the second tube.

10. The suture system according to claim 9, characterized in that, The first section of the guide wire is configured with a limiting part near the second section. The limiting part can limit the end face of the second tube near the first end, so that when the guide wire extends out of the first channel from the second end under the action of external force, it can pull the capture net from the unfolded state to the retracted state. Alternatively, the stitching system may further include an elastic element made of a polymer material, which is disposed within the first channel and located on the outside of the first segment. The elastic element is used to drive the capture net to switch from the deployed state to the retracted state.

11. The suture system according to claim 7, characterized in that, A limiting surface is formed at the connection between the second segment and the first segment, and the limiting surface limits the opening of the first channel near the second end; The limiting surface is an annular plane, and the limiting surface is perpendicular to the axial direction of the guide wire; Alternatively, the limiting surface is an annular inclined surface, and the diameter of the limiting surface gradually increases from the first segment toward the second segment; Alternatively, the limiting surface is an annular inclined surface, and the diameter of the limiting surface gradually decreases from the first segment toward the second segment.

12. The suture system according to claim 7, characterized in that, The guidewire further includes a third segment, with the second segment connected between the first segment and the third segment. The diameter of the third segment is substantially the same as that of the first segment, and the diameters of both the first segment and the third segment are smaller than the diameter of the second segment. A guide surface is formed at the connection between the second segment and the third segment, and the diameter of the guide surface gradually increases from the third segment toward the second segment to ensure a smooth connection between the third segment and the second segment.

Images