A barbed suture and method of making same

Abstract

This invention belongs to the field of medical device technology and discloses a barbed suture and its preparation method. The barbed suture includes a suture body and barbs formed on the suture body. The preparation method involves irradiating the horizontally arranged suture body with a laser beam emitted from a laser, the temperature of which is higher than the melting temperature of the suture body. T m At the same time, it is lower than the thermal decomposition temperature of the suture body. T d The laser is positioned directly above or slightly above the suture body. The laser beam is decomposed into horizontal and vertical components. The horizontal component is parallel to the length of the suture body, and the vertical component points downwards. During irradiation, the laser reciprocates along a horizontal direction perpendicular to the length of the suture body, causing the laser beam to cut the suture body and form barbs. This invention allows the barbs to bend and curl upwards, achieving high-curvature barbs, and the resulting barbed sutures do not suffer from insufficient strength due to a reduction in suture diameter.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical supplies, and relates to a barbed suture and a preparation method thereof. BACKGROUND

[0002] In surgical operations, suture is the key material for connecting and fixing tissues. However, the traditional suture needs to be fixed by knotting, but knotting can cause unbalanced tension and induce local tissue ischemia or knot extrusion (providing a channel for bacterial invasion).

[0003] To solve the above problems, a barb structure is usually designed on the suture, which can be pierced into the tissue and locked in position during suturing, without the need for knotting to fix it, realizing "knotless suturing", simplifying the operation and improving the suturing efficiency. Moreover, this structure makes the suture "only go in but not come out", and each barb grasps the tissue like a one-way valve, continuously providing stable tension and reducing the risk of tissue sliding.

[0004] However, the current cutting of barbs on the suture is through laser beam subtractive cutting of the suture, which also reduces the diameter of the suture, and further leads to insufficient strength of the suture. In addition, the barb structure formed by the prior art has insufficient height, which also makes the holding force of the barb low, which is not safe and effective for suturing that needs to overcome a larger tension trauma.

[0005] For example, patent application US20130180966A1 discloses a laser cutting system and method for manufacturing self-locking suture, which first determines the first volume and the second volume of suture material on the surface of the suture, then guides the laser beam to irradiate the suture, moves from the root of the barb to the head of the barb to remove all suture material in the first volume except the second volume, and forms a slot on the suture, so that the second volume of suture material forms a tissue fixator protruding from the surface of the laser-cut suture, i.e. a barb with multiple conformations. The slot formed by the barb processed in this way cannot form a mechanically cut barb that is raised, which further leads to a low holding force of the barb on the suture. Moreover, this subtractive cutting of the suture also causes the diameter of the suture to decrease, which further leads to insufficient strength of the suture.

[0006] In summary, the existing technology focuses on the formation of the barb, ignoring the problems of the height of the barb after formation and the reduction of the strength of the suture.

[0007] Therefore, it is necessary to provide a preparation method of a barbed suture that can solve the above problems. SUMMARY

[0008] The purpose of the present application is to solve the problems existing in the prior art and provide a barbed suture and a preparation method thereof.

[0009] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0010] A preparation method of barbed suture, which adopts a laser to emit a laser beam to irradiate a suture body, the temperature of the laser beam is higher than the melting temperature T m of the suture body (to ensure local melting) and lower than the thermal decomposition temperature T d of the suture body (to avoid excessive melting or material degradation), and the suture body is arranged horizontally.

[0011] The laser is located above the suture body or above the side of the suture body, preferably above the side of the suture body, and the light beam direction vector of the laser beam is decomposed into a horizontal component and a vertical component, wherein the horizontal component is parallel to the length direction of the suture body, and the vertical component is downward.

[0012] During the irradiation process, the laser reciprocates along the horizontal direction perpendicular to the length direction of the suture body, so that the laser beam cuts the suture body to form a barb.

[0013] The preparation method of barbed suture as described above, the included angle θ between the light beam direction of the laser beam and the length direction of the suture body is preferably 10°-30°, and further preferably 20°, and this angle range can effectively form a barb structure while avoiding excessive damage to the suture body.

[0014] The preparation method of barbed suture as described above, the distance between the laser and the suture body is preferably 5-20 mm, and further preferably 20 mm, and a suitable distance is conducive to avoiding thermal damage and also conducive to avoiding the influence of energy attenuation on barb formation; the reciprocating speed of the laser is preferably 100-500 mm / s, and further preferably 300 mm / s, and a suitable speed is conducive to avoiding excessive formation and also conducive to avoiding incomplete barb formation; the preferred distance of single reciprocation of the laser (i.e. the total distance moved in the process that the laser starts from the starting position, passes through a certain path to reach the other end, and then returns to the starting position) is 1-3 times the diameter L c of the suture body, and the further preferred distance of single reciprocation of the laser is 1 times the diameter L c of the suture body.

[0015] The preparation method of barbed suture as described above, the glass transition temperature T g of the suture body is preferably -10-80°C, and further preferably -10-70°C, and needs to be higher than the body temperature (~37°C) to avoid softening in the body, and also needs to be lower than the laser processing temperature.

[0016] In the above-described method for preparing barbed sutures, the power P of the laser is preferably 1~80W, more preferably 11~54W. Appropriate power is beneficial for the smooth barb forming and also helps to avoid ablation of the suture body.

[0017] The laser beam irradiates the suture body for a time t, preferably 0.001~0.1s, more preferably 0.05~0.1s, as short pulses can reduce thermal effects;

[0018] The diameter L of the suture body c Preferably, the value is 0.00005~0.001m, more preferably 0.0002~0.000570m;

[0019] The thermal conductivity k of the suture body is preferably 0.1~0.3 W / (m·K), more preferably 0.2 W / (m·K). The low thermal conductivity can limit the heat-affected zone and avoid excessive heating of the material around the barbs.

[0020] The dynamic viscosity η of the suture body is preferably 10. 2 ~10 4 Pa·s, more preferably 100~200 Pa·s, dynamic viscosity affects the fluidity of the suture body and the sharpness of the barb forming during laser processing;

[0021] The surface tension γ of the suture body is preferably 0.02~0.05 N / m, more preferably 0.03~0.04 N / m. The surface tension controls the wettability and edge morphology of the suture body during barb forming.

[0022] The elastic modulus E of the suture body is preferably 1~10GPa, more preferably 1.5~2.0GPa. The elastic modulus needs to match the mechanical requirements of the surgical site (such as the need for moderate flexibility in soft tissue suturing). When the elastic modulus is 1~5GPa, absorbable materials can be selected, and when the elastic modulus is 2~10GPa, non-absorbable materials can be selected.

[0023] The diameter d of the laser beam is preferably 50~200μm, and more preferably 50mm;

[0024] Melting temperature T of the suture body m Preferably ≥373K, more preferably 373~543K, to ensure that local heating during laser processing does not lead to overall melting and deformation. When the melting temperature does not exceed 423K, absorbable materials such as PLA and PGA can be selected. When the melting temperature exceeds 423K, non-absorbable materials such as polypropylene and nylon can be selected.

[0025] The preferred ambient temperature T0 (i.e., cooling temperature) is higher than the glass transition temperature T of the suture body. gAt the same time, it is lower than the melting temperature T of the suture body. m This is conducive to the formation of a larger, more stable, and more ordered crystal structure, thereby increasing the strength of the barbs.

[0026] In the method for preparing a barbed suture as described above, preferably, the height h of the barb is first set, and then the power (energy density input per unit time) P of the laser, the time t for the laser beam to irradiate the suture body, and the diameter L of the suture body are found according to the following relationship. c The following parameters are considered: thermal conductivity of the suture body (characterizing thermal diffusivity) k; dynamic viscosity of the suture body (characterizing flow resistance in the molten state) η; surface tension of the suture body (characterizing surface energy in the molten state) γ; elastic modulus of the suture body (characterizing resistance to deformation) E; diameter of the laser beam d; melting temperature of the suture body T. m The ambient temperature is T0 before processing.

[0027] ;

[0028] In the formula, C is a comprehensive constant, preferably ranging from 0.1 to 10. Specific values ​​need to be experimentally calibrated. The units are used to ensure consistency between the units on both sides of the above relationship; v gas The gas flow rate is preferably 0.5~5 m / s, and more preferably 0.5~1 m / s; h, P, t, L c ,k,η,γ,E,d,T m The units of T0 are μm, W, s, m, W / (m·K), Pa·s, N / m, Pa, m, K, K, respectively.

[0029] The derivation of the above formula is as follows:

[0030] (1) Laser energy density ( Relationship between ) and melt volume (V)

[0031] Based on "circular light spot area" ) Calculate laser energy density ( Energy input per unit area):

[0032] ①;

[0033] Based on the principle of "energy conservation"—the input energy must overcome the material's thermal conduction losses, and the remaining energy is used for melting—the melt volume (V) is related to the laser energy density (…). It is directly proportional to thermal conductivity (k) and temperature difference (T). m -T0) is inversely proportional:

[0034] ②.

[0035] (2) Cooling rate (α) and gas flow rate (v) gas The relationship between )

[0036] Newton's law of cooling for forced convection cooling:

[0037] ③;

[0038] In the formula, The convective heat transfer coefficient is related to the gas flow rate as follows: (Empirical formula, applicable to air);

[0039] Let be the density of the suture material in its molten state, expressed in kg / m³. When the suture material is PLA... It is 1250 kg / m³;

[0040] Let be the specific heat capacity of the suture material in the molten state, J / (kg·K). When the suture material is PLA, It is 1800 J / (kg·K);

[0041] The diameter of the suture body;

[0042] therefore:

[0043] ④;

[0044] In the formula, These are constants related to the properties and geometry of the gas.

[0045] (3) The relationship between the flow of the suture body and the height (h) of the barbs

[0046] The flow of the suture body is controlled by the capillary number (Ca), which depends on the flow velocity (v), dynamic viscosity (η), and surface tension (γ) of the suture body. The calculation formula is as follows:

[0047] ⑤;

[0048] The relationship between the flow velocity (v) of the suture body and the height of the barb (h) and the time (t) of the laser beam irradiating the suture body is as follows:

[0049] ⑥;

[0050] The lower the surface tension (γ) of the suture body, the stronger the fluidity of the suture body, and the greater the height (h) of the barbs; the lower the dynamic viscosity (η) of the suture body, the stronger the fluidity of the suture body, and the greater the height (h) of the barbs; the longer the laser beam irradiates the suture body (t), the more complete the flow, and the greater the height (h) of the barbs; therefore, the relationship between the height (h) of the barbs, the surface tension (γ) of the suture body, the time (t) of the laser beam irradiating the suture body, and the dynamic viscosity (η) of the suture body is as follows:

[0051] ⑦.

[0052] (4) Cooling, curing and elastic recovery

[0053] The cooling rate (α) affects the curing time; a higher cooling rate (α) results in a shorter curing time and a smaller barb height (h). The elastic modulus (E) of the suture body inhibits deformation; a higher elastic modulus (E) of the suture body results in a stronger effect in inhibiting deformation and a smaller barb height (h). Therefore, the relationship between barb height (h), the elastic modulus (E) of the suture body, and the cooling rate (α) is as follows:

[0054] ⑧.

[0055] (5) Comprehensive coupling relationship

[0056] From formulas ⑦ and ⑧, it can be seen that the barb height is affected by both flow and cooling. Combining these factors, we get: — (Combined Formula 1);

[0057] Combining formula 1 and formula ④, we get: — (Combined Formula 2);

[0058] In Formula ②, the molten volume (V) is directly proportional to the laser power (P), while the height of the barb (h) depends on the amount of molten material. Therefore, the laser power (P) and the laser beam diameter (d) are introduced, combined with Formula ②. Substituting the terms into equation 2 and combining constants (such as π), we obtain the following relationship:

[0059] ;

[0060] In the formula, C is a dimensionless comprehensive constant, ranging from 0.1 to 10, and its specific value needs to be experimentally calibrated; v gas The gas flow rate is 0.5~5 m / s.

[0061] The final actual value of the barb height h is 90% to 99% of the set value of the barb height h. Therefore, the actual value of the barb height h is close to the set value of the barb height h. The above relationship can be used to guide production and processing to prepare barb sutures with ideal barb height h.

[0062] The present invention also provides a barbed suture, which is prepared by a method for preparing a barbed suture as described in any of the preceding claims, comprising a suture body and barbs formed on the suture body.

[0063] As described above, in a barbed suture, the barbs are preferably arranged in a spiral direction on the suture body.

[0064] The barbed suture described above has a barbed gripping force of 7.2~10.65N for the barbs.

[0065] The principle of this invention is as follows:

[0066] Existing technology uses a laser beam perpendicular to the length of the suture, penetrating it and then moving along a pre-set trajectory to cut the suture. During this cutting process, the laser beam heats the suture continuously, meaning that various points on the same line are simultaneously within the heat-affected zone (e.g., ...). Figure 1 As shown, the suture line represented by the dashed line in the diagram is heated simultaneously at this time. This continuous heating method first heats the suture line to a molten state, and then, under the continuous action of the laser beam, it is further heated until vaporization occurs. The vaporized material separates from the suture line and enters the surrounding air, ultimately forming only a groove on the suture line, and cannot form the raised barbs like those from mechanical cutting.

[0067] like Figure 2 As shown, the laser beam of this invention moves back and forth along the dotted line, employing point heating. Although the intervals are short, the heating of each point on the same line is sequential and intermittent. This allows the suture to remain molten after melting rather than being heated to vaporization, and provides sufficient time for movement under internal stress. When the laser beam returns, the material is reheated, preventing it from cooling to a glassy state, thus maintaining its movable state. This invention uses a laser beam to heat the suture, gradually ablating it from the tip of the barb towards the root. The laser beam heats the inner surface and root of the barb, melting the inner surface while the outer surface remains solid. Under internal stress, the uneven force on the inner and outer sides causes the barb to bend and curl, achieving a high degree of curl.

[0068] The method for preparing barbed sutures in this invention is not a traditional method of subtractive cutting of the suture, so there will be no situation where the strength is insufficient due to the reduction of the suture diameter.

[0069] Beneficial effects:

[0070] (1) The present invention uses point heating to make back-and-forth movement in the cutting area, so that the suture can remain in a molten state after melting instead of being heated to vaporization, and has enough time to move under internal stress. When the laser beam moves back, the material is heated again so that it does not cool to a glassy state, that is, it always remains in a movable state. This heating method can improve the crystallinity of the barb, thereby improving the strength of the barb.

[0071] (2) The present invention heats the suture with a laser beam, gradually ablates it from the tip of the barb to the root, and heats the inner side of the barb and the root of the barb, so that the inner side of the barb melts while the outer side remains solid. Under the action of internal stress, the inner and outer sides are subjected to uneven force, causing the barb to bend and lift up, thus achieving a barb with a high degree of lifting.

[0072] (3) The method of preparing barbed sutures in this invention is not the traditional method of subtractive cutting of sutures, so there will be no situation where the strength is insufficient due to the reduction of the diameter of the suture.

[0073] (4) The present invention controls the angle θ between the laser beam direction and the length direction of the suture body to be 10°~30°, which may effectively form a barb structure while avoiding excessive damage to the suture body. Attached Figure Description

[0074] Figure 1 This is a diagram illustrating the process of laser beam processing of sutures using existing technology. In the diagram, the dashed line represents the heating path of the suture, the red arrow indicates the direction of laser beam irradiation, and the blue line represents the outline of the barbs.

[0075] Figure 2 This is a diagram showing the path of the laser beam processing the suture during the present invention; in the diagram, the dashed line represents the heating path of the suture, and the blue line is the outline of the barbs;

[0076] Figure 3 This is a schematic diagram of the barbed suture of the present invention;

[0077] Figure 4 This is a schematic diagram of the processing of the barbed suture of the present invention. a is the front view, b is the top view, and c is a schematic diagram of the step-by-step forming of the circled area in a. In the figure, the black solid arrows are the vertical components of the laser beam, the black dashed arrows are the horizontal components of the laser beam, the red arrows indicate the irradiation direction of the laser beam, and the green arrows indicate the movement direction of the laser beam.

[0078] Figure 5 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment A1 and Comparative Example A1 of the present invention.

[0079] Figure 6 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment A2 and Comparative Example A2 of the present invention.

[0080] Figure 7 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment A3 and Comparative Example A3 of the present invention.

[0081] Figure 8 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment A4 and Comparative Example A4 of the present invention.

[0082] Figure 9 This is a schematic diagram of the barbed suture of the present invention;

[0083] Figure 10 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barb sutures in Embodiment B1 and Comparative Example B1 of the present invention.

[0084] Figure 11 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barb sutures in Embodiment B2 and Comparative Example B2 of the present invention.

[0085] Figure 12 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barb sutures in Embodiment B3 and Comparative Example B3 of the present invention.

[0086] Figure 13 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barb sutures in Embodiment B4 and Comparative Example B4 of the present invention.

[0087] Figure 14 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment C1 and Comparative Example C1 of the present invention.

[0088] Figure 15 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment C2 and Comparative Example C2 of the present invention.

[0089] Figure 16 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment C3 and Comparative Example C3 of the present invention.

[0090] Figure 17 This is a schematic diagram showing the gripping force of the barbs measured in five samples of barbed sutures in Embodiment C4 and Comparative Example C4 of the present invention. Detailed Implementation

[0091] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0092] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0093] Thermal conductivity: The suture bodies in each embodiment and comparative example were used as samples, and the thermal conductivity of the samples was tested according to the hot wire method in ASTM D5470 standard.

[0094] Dynamic viscosity: The suture bodies in each embodiment and comparative example were used as samples, and the dynamic viscosity of the samples was tested by the capillary rheometer method in ASTM D1238.

[0095] Surface tension: The suture bodies in each embodiment and comparative example were used as samples, and the surface tension of the samples was tested by the pendant drop method in ASTM D724-99.

[0096] Elastic modulus: The suture bodies in each embodiment and comparative example were used as samples, and the elastic modulus of the samples was tested by the uniaxial tensile test method in ASTM D2256.

[0097] The gripping force of the barbs: The barbed sutures prepared in each embodiment and comparative example were used as samples. Five samples of each type were selected for testing. The gripping force of the five samples was then tested using the soft tissue embedding stretching method, and the average value was calculated. The testing procedure was as follows: An 8cm incision was made in fresh pig muscle. Using the sample and the corresponding suture, double needles were inserted into the pig muscle from the middle of the incision and continuously sutured towards both ends. A single needle was inserted from one side of the incision and continuously sutured towards the other side. The needles were inserted and exited perpendicularly, with the insertion and exit distances consistent, and the suture depth greater than the suture distance. A backstitch was made at the end of the incision for fixation. Excess suture was trimmed after completion; no knotting was required. The stitch spacing was 0.7cm, and the total suture length was 10cm. After suturing, a tensile testing machine is used to hook the suture thread in the middle of the suture site and fix the sutured tissue at the other end. The test is conducted at a test speed of 20 mm / min until the suture thread comes off the suture site. At the same time, the maximum force when the suture thread is pulled out is recorded, which is the barb's gripping force.

[0098] Example A1

[0099] A method for preparing a barbed suture, comprising the following steps:

[0100] (1) Determine the material of the suture body and the diameter L of the suture body. c and ambient temperature T0;

[0101] The suture body is made of PPDO (polydioxanone), which determines its thermal conductivity k of 0.2 W / (m·K), dynamic viscosity η of 200 Pa·s, surface tension γ of 0.03 N / m, elastic modulus E of 1.5 GPa, and melting temperature T. m It is 383K;

[0102] The average diameter L of the suture body c It is 0.000535m;

[0103] The ambient temperature T0 is 293K;

[0104] (2) First, set the height h of the barb to 125 μm, and then determine the power P of the laser (using a 976 nm wavelength-stabilized semiconductor pump source) to be 19 W, the time t for the laser beam to irradiate the suture body to be 0.05 s, and the diameter d of the laser beam to be 0.00005 m according to the following relationship:

[0105] ;

[0106] In the formula, C is a comprehensive constant with a value of 0.1, and the unit is used to ensure that the units on both sides of the above relationship are consistent; v gas The gas flow rate is 1 m / s; h, P, t, L c ,k,η,γ,E,d,T m The units of T0 are μm, W, s, m, W / m·K, Pa·s, N / m, Pa, m, K, K, respectively.

[0107] (3) First, the suture body (its glass transition temperature T) g The laser is positioned horizontally (at -10°C) and placed above and to the side of the suture body. The direction vector of the laser beam is decomposed into a horizontal component and a vertical component. The horizontal component is parallel to the length direction of the suture body, and the vertical component points downward. The vertical distance between the laser and the suture body is 20 mm.

[0108] (4) The suture body is processed by irradiating it with a laser beam emitted by a laser. The processing procedure is as follows: Figure 4As shown, during irradiation, the laser reciprocates horizontally along the length of the suture body, causing the laser beam to cut the suture body and form barbs. The angle θ between the laser beam direction and the length of the suture body is 20°, the laser's reciprocating speed is 300 mm / s, and the distance of a single reciprocating motion is the average diameter L of the suture body. c 1 times.

[0109] The final barbed suture includes a suture body and barbs formed on the suture body;

[0110] Barbs on the suture line (such as barbs) Figure 3 The actual value of the height h (i.e., the average height of all barbs on the suture line) is 99% of the set value of the barb height h. The gripping force of the barbs on the suture line is 10.65 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 5 As shown; Figure 9 As shown, all barbs on the suture body are arranged in a spiral direction.

[0111] Comparative Example A1

[0112] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example A1, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example A1, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example A1.

[0113] The final barb holding force of the suture was 4.89 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 5 As shown.

[0114] Example A2

[0115] A method for preparing a barbed suture, basically the same as in Example A1, except that: the average diameter L of the suture body is... c It is 0.00037m;

[0116] In step (2), the height h of the barb is set to 96 μm, the power P of the laser is 14 W, and the gas flow rate v is... gas It is 0.6 m / s.

[0117] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 97% of the set value of the barb height h. The gripping force of the barbs on the suture line is 8.06 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 6 As shown; all barbs on the suture body are arranged in a spiral direction.

[0118] Comparative Example A2

[0119] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example A3, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example A2, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example A2.

[0120] The final barb gripping force of the barb on the suture line was 3.82 N. The gripping force of the barbs on the five samples used in the test was as follows: Figure 6 As shown.

[0121] Example A3

[0122] A method for preparing a barbed suture, basically the same as in Example A1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0003245m;

[0123] In step (2), the height h of the barb is set to 84 μm, the power P of the laser is 12 W, and the gas flow rate v is... gas It is 0.5 m / s.

[0124] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 95% of the set value of the barb height h. The gripping force of the barbs on the suture line is 8.30 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 7 As shown; all barbs on the suture body are arranged in a spiral direction.

[0125] Comparative Example A3

[0126] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example A3, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example A3, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example A3.

[0127] The final barb holding force of the suture was 3.67 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 7 As shown.

[0128] Example A4

[0129] A method for preparing a barbed suture, basically the same as in Example A1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0002245m;

[0130] In step (2), the height h of the barb is set to 53 μm, the power P of the laser is 11 W, and the gas flow rate v is...gas It is 0.5 m / s.

[0131] The final actual value of the barb height h on the suture line (i.e., the average value of all barb heights on the suture line) is 95% of the set value of the barb height h. The gripping force of the barbs on the suture line is 7.20 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 8 As shown; all barbs on the suture body are arranged in a spiral direction.

[0132] Comparative Example A4

[0133] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example A4, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example A4, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example A4.

[0134] The final barb holding force of the suture line was 3.70 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 8 As shown.

[0135] Comparing the gripping force of the barbs on the sutures prepared in Examples A1-A4 and Comparative Examples A1-A4, it can be seen that, compared with the blade cutting in Comparative Examples A1-A4, the laser beam heating of the suture in Examples A1-A4 gradually ablates from the tip of the barb towards the root. The laser beam heats the inner surface and root of the barb, melting the inner surface while the outer surface remains solid. Under the action of internal stress, the uneven force on the inner and outer sides causes the barb to bend and curl up, achieving a high degree of curling. In addition, by precisely controlling parameters such as power, laser beam diameter, and the time the laser beam irradiates the suture body, the laser can precisely control the size, shape, and distribution of the barbs, and the cut barbs are more uniform. Furthermore, the blade-cut barbs do not change the crystal structure of the suture material. The barb structure is smaller and softer. In application, the gripping force of the softer barbs on soft tissue is relatively low.

[0136] Comparative Example A5

[0137] A method for preparing a barbed suture, wherein the cutting object and cutting depth are the same as in Example A4, and the cutting is performed using a laser beam (same as in Example A4), wherein the beam direction of the laser beam is set to the horizontal direction and perpendicular to the length direction of the suture.

[0138] The experiment showed that the gripping force of the barbs on the suture line prepared in Comparative Example A5 was significantly lower than that in Example A4. This is because the processing method in Comparative Example A5 would result in the formation of a narrow groove on the suture line, making it impossible to form barbs that are raised like those produced by mechanical cutting, thus resulting in a lower gripping force of the barbs on the suture line.

[0139] Example B1

[0140] A method for preparing a barbed suture, comprising the following steps:

[0141] (1) Determine the material of the suture body and the diameter L of the suture body. c and ambient temperature T0;

[0142] The suture body is made of PET (polyester), which determines its thermal conductivity k of 0.2 W / (m·K), dynamic viscosity η of 200 Pa·s, surface tension γ of 0.04 N / m, elastic modulus E of 3 GPa, and melting temperature T. m It is 523K;

[0143] The average diameter L of the suture body c It is 0.000535m;

[0144] The ambient temperature T0 is 353K;

[0145] (2) First, set the height h of the barb to 142 μm, and then determine the power P of the laser (using a 976 nm wavelength-stabilized semiconductor pump source) to be 54 W, the time t for the laser beam to irradiate the suture body to be 0.1 s, and the diameter d of the laser beam to be 0.00005 m according to the following relationship:

[0146] ;

[0147] In the formula, C is a comprehensive constant with a value of 0.1, and the unit is used to ensure that the units on both sides of the above relationship are consistent; v gas The gas flow rate is 1 m / s; h, P, t, L c ,k,η,γ,E,d,T m The units of T0 are μm, W, s, m, W / m·K, Pa·s, N / m, Pa, m, K, K, respectively.

[0148] (3) First, the suture body (its glass transition temperature T) g The laser is positioned horizontally (at -10°C) and placed above and to the side of the suture body. The direction vector of the laser beam is decomposed into a horizontal component and a vertical component. The horizontal component is parallel to the length direction of the suture body, and the vertical component points downward. The vertical distance between the laser and the suture body is 20 mm.

[0149] (4) The suture body is processed by irradiating it with a laser beam. During the irradiation, the laser moves back and forth in a horizontal direction perpendicular to the length of the suture body, so that the laser beam cuts the suture body and forms barbs. The angle θ between the laser beam direction and the length of the suture body is 20°, the reciprocating speed of the laser is 300 mm / s, and the distance of a single reciprocating motion of the laser is the average diameter L of the suture body. c 1 times.

[0150] The final barbed suture includes a suture body and barbs formed on the suture body;

[0151] The actual value of the barb height h on the suture line (i.e., the average value of all barb heights on the suture line) is 96% of the set value of the barb height h. The gripping force of the barbs on the suture line is 10.93 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 10 As shown; all barbs on the suture body are arranged in a spiral direction.

[0152] Comparative Example B1

[0153] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example B1, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example B1, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example B1.

[0154] The final barb holding force of the suture line was 5.75 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 10 As shown.

[0155] Example B2

[0156] A method for preparing a barbed suture, basically the same as in Example B1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0003695m;

[0157] In step (2), the height h of the barb is set to 95 μm, the power P of the laser is 35 W, and the gas flow rate v is set to 35 μm. gas It is 0.6 m / s.

[0158] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 93% of the set value of the barb height h. The gripping force of the barbs on the suture line is 9.15N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 11 As shown; all barbs on the suture body are arranged in a spiral direction.

[0159] Comparative Example B2

[0160] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example B2, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example B2, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example B2.

[0161] The final barb holding force of the suture line was 4.33 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 11 As shown.

[0162] Example B3

[0163] A method for preparing a barbed suture, basically the same as in Example B1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0003245m;

[0164] In step (2), the height h of the barb is set to 83 μm, the power P of the laser is 30 W, and the gas flow rate v is... gas It is 0.5 m / s.

[0165] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 90% of the set value of the barb height h. The gripping force of the barbs on the suture line is 8.43 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 12 As shown; all barbs on the suture body are arranged in a spiral direction.

[0166] Comparative Example B3

[0167] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example B3, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example B3, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example B3.

[0168] The final barb holding force of the suture was 3.89 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 12 As shown.

[0169] Example B4

[0170] A method for preparing a barbed suture, basically the same as in Example B1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0002245m;

[0171] In step (2), the height h of the barb is set to 56 μm, the power P of the laser is 29 W, and the gas flow rate v is...gas It is 0.5 m / s.

[0172] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 90% of the set value of the barb height h. The gripping force of the barbs on the suture line is 7.63N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 13 As shown; all barbs on the suture body are arranged in a spiral direction.

[0173] Comparative Example B4

[0174] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example B4, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example B4, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example B4.

[0175] The final barb gripping force of the barb on the suture line was 3.62 N. The gripping force of the barbs on the five samples used in the test was as follows: Figure 13 As shown.

[0176] A comparison of the gripping force of the barbs on the sutures prepared in Examples B1-B4 and Comparative Examples B1-B4 shows that, compared to the blade cutting in Comparative Examples B1-B4, the laser beam heating of the suture in Examples B1-B4 gradually ablates from the tip of the barb towards the root. The laser beam heats the inner surface and root of the barb, melting the inner surface while the outer surface remains solid. Under internal stress, the uneven force on the inner and outer sides causes the barb to bend and curl up, achieving a high degree of curling. In addition, by precisely controlling parameters such as power, laser beam diameter, and the time the laser beam irradiates the suture body, the laser can precisely control the size, shape, and distribution of the barbs, resulting in more uniform and consistent barbs. Furthermore, the blade-cut barbs do not change the crystalline structure of the suture material. The barb structure is smaller and softer. In application, the gripping force of the softer barbs on soft tissue is relatively low.

[0177] Example C1

[0178] A method for preparing a barbed suture, comprising the following steps:

[0179] (1) Determine the material of the suture body and the diameter L of the suture body. c and ambient temperature T0;

[0180] The suture body is made of PP (polypropylene), which determines its thermal conductivity k of 0.2 W / (m·K), dynamic viscosity η of 100 Pa·s, surface tension γ of 0.03 N / m, elastic modulus E of 2 GPa, and melting temperature T. m It is 433K;

[0181] The average diameter L of the suture body c It is 0.000545m;

[0182] The ambient temperature T0 is 293K;

[0183] (2) First, set the height h of the barb to 143 μm, and then determine the power P of the laser (using a 976 nm wavelength-stabilized semiconductor pump source) to be 22 W, the time t for the laser beam to irradiate the suture body to be 0.05 s, and the diameter d of the laser beam to be 0.00005 m according to the following relationship:

[0184] ;

[0185] In the formula, C is a comprehensive constant with a value of 0.1, and the unit is used to ensure that the units on both sides of the above relationship are consistent; v gas The gas flow rate is 1 m / s; h, P, t, L c ,k,η,γ,E,d,T m The units of T0 are μm, W, s, m, W / m·K, Pa·s, N / m, Pa, m, K, K, respectively.

[0186] (3) First, the suture body (its glass transition temperature T) g The laser is positioned horizontally (at 70°C) and placed above and to the side of the suture body. The direction vector of the laser beam is decomposed into a horizontal component and a vertical component. The horizontal component is parallel to the length direction of the suture body, and the vertical component points downward. The vertical distance between the laser and the suture body is 20 mm.

[0187] (4) The suture body is processed by irradiating it with a laser beam. During the irradiation, the laser moves back and forth in a horizontal direction perpendicular to the length of the suture body, so that the laser beam cuts the suture body and forms barbs. The angle θ between the laser beam direction and the length of the suture body is 20°, the reciprocating speed of the laser is 300 mm / s, and the distance of a single reciprocating motion of the laser is the average diameter L of the suture body. c 1 times.

[0188] The final barbed suture includes a suture body and barbs formed on the suture body;

[0189] The actual value of the barb height h on the suture line (i.e., the average value of all barb heights on the suture line) is 96% of the set value of the barb height h. The gripping force of the barbs on the suture line is 10.48 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 14 As shown; all barbs on the suture body are arranged in a spiral direction.

[0190] Comparative Example C1

[0191] A method for preparing a barbed suture, wherein the cutting object is the same as in Example C1, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example C1, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example C1.

[0192] The final barb holding force of the suture was 5.5 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 14 As shown.

[0193] Example C2

[0194] A method for preparing a barbed suture, basically the same as in Example C1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0003695m;

[0195] In step (2), the height h of the barb is set to 99 μm, the power P of the laser is 15 W, and the gas flow rate v is... gas It is 0.6 m / s.

[0196] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 93% of the set value of the barb height h. The gripping force of the barbs on the suture line is 8.29 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 15 As shown; all barbs on the suture body are arranged in a spiral direction.

[0197] Comparative Example C2

[0198] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example C2, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example C2, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example C2.

[0199] The final barb gripping force of the barb on the suture line was 3.9 N. The gripping force of the barbs on the five samples used in the test was as follows: Figure 15 As shown.

[0200] Example C3

[0201] A method for preparing a barbed suture, basically the same as in Example C1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0003245m;

[0202] In step (2), the height h of the barb is set to 81 μm, the power P of the laser is 12 W, and the gas flow rate v is... gas It is 0.5 m / s.

[0203] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 90% of the set value of the barb height h. The gripping force of the barbs on the suture line is 8.24 N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 16 As shown; all barbs on the suture body are arranged in a spiral direction.

[0204] Comparative Example C3

[0205] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example C3, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example C3, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example C3.

[0206] The final barb gripping force of the obtained barb suture was 3.63 N. The gripping force of the barbs on the five samples used in the test was as follows: Figure 16 As shown.

[0207] Example C4

[0208] A method for preparing a barbed suture, basically the same as in Example C1, except that: in step (1), the average diameter L of the suture body is... c It is 0.0002245m;

[0209] In step (2), the height h of the barb is set to 56 μm, the power P of the laser is 12 W, and the gas flow rate v is... gas It is 0.5 m / s.

[0210] The final actual value of the barb height h on the suture line (i.e., the average height of all barbs on the suture line) is 90% of the set value of the barb height h. The gripping force of the barbs on the suture line is 7.55N. The gripping force of the barbs on the 5 samples used in the test is as follows: Figure 17 As shown; all barbs on the suture body are arranged in a spiral direction.

[0211] Comparative Example C4

[0212] A method for preparing a barbed suture, wherein the object to be cut is the same as in Example C4, the cutting method is oblique cutting with a blade, the oblique cutting depth is the same as in Example C4, and the angle between the oblique cutting direction and the length direction of the suture body is the same as the angle between the laser beam direction and the length direction of the suture body in Example C4.

[0213] The final barb holding force of the suture was 3.54 N. The holding force of the barbs on the five samples used in the test was as follows: Figure 17 As shown.

[0214] A comparison of the gripping force of the barbs on the sutures prepared in Examples C1-C4 and Comparative Examples C1-C4 shows that, compared to the blade cutting in Comparative Examples C1-C4, the laser beam heating of the suture in Examples C1-C4 gradually ablates from the tip of the barb towards the root. The laser beam heats the inner surface and root of the barb, melting the inner surface while the outer surface remains solid. Under internal stress, the uneven force on the inner and outer sides causes the barb to bend and curl up, achieving a high degree of curling. In addition, by precisely controlling parameters such as power, laser beam diameter, and the time the laser beam irradiates the suture body, the laser can precisely control the size, shape, and distribution of the barbs, resulting in more uniform and consistent barbs. Furthermore, the blade-cut barbs do not change the crystal structure of the suture material, and the barb structure is smaller and softer. In application, the gripping force of the softer barbs on soft tissue is relatively low.

[0215] The barb cutting method of the present invention is used in Examples B1-B4 and Examples C1-C4, and the gripping force of the barbs formed therefrom is superior to that of the prior art.

Claims

1. A method for preparing a barbed suture, comprising irradiating the suture body with a laser beam emitted from a laser, wherein the temperature of the laser beam is higher than the melting temperature T of the suture body. m At the same time, it is lower than the thermal decomposition temperature T of the suture body. d Its characteristics are, The suture body is arranged horizontally; The laser is located directly above or to the side of the suture body. The direction vector of the laser beam is decomposed into a horizontal component and a vertical component. The horizontal component is parallel to the length direction of the suture body, and the vertical component is downward. During the irradiation process, the laser moves back and forth in a horizontal direction perpendicular to the length of the suture body, causing the laser beam to cut the suture body and form barbs; The laser power P is 1~80W; The laser beam irradiates the suture body for a time t of 0.001~0.1s; The diameter L of the suture body c The value is 0.00005~0.001m; The thermal conductivity k of the suture body is 0.1~0.3 W / (m·K); The dynamic viscosity η of the suture body is 10. 2 ~10 4 Pa·s; The surface tension γ of the suture body is 0.02~0.05 N / m; The elastic modulus E of the suture body is 1~10 GPa; The diameter d of the laser beam is 50~200μm; Melting temperature T of the suture body m ≥373K; The ambient temperature T0 is higher than the glass transition temperature T of the suture body. g At the same time, it is lower than the melting temperature T of the suture body. m ; First, set the height h of the barb. Then, based on the following relationships, find the corresponding laser power P, the time t for the laser beam to irradiate the suture body, and the diameter L of the suture body. c The following parameters are considered: thermal conductivity k of the suture body, dynamic viscosity η of the suture body, surface tension γ of the suture body, elastic modulus E of the suture body, diameter d of the laser beam, and melting temperature T of the suture body. m The ambient temperature is T0 before processing. ； In the formula, C is a comprehensive constant with a value ranging from 0.1 to 10, and the unit is used to ensure that the units on both sides of the above relationship are consistent; v gas The gas flow rate is 0.5~5 m / s; h, P, t, L c ,k,η,γ,E,d,T m The units of T0 are μm, W, s, m, W / (m·K), Pa·s, N / m, Pa, m, K, K, respectively.

2. The method for preparing a barbed suture according to claim 1, characterized in that, The angle θ between the laser beam direction and the length direction of the suture body is 10°~30°.

3. The method for preparing a barbed suture according to claim 1, characterized in that, The vertical distance between the laser and the suture body is 5~20mm; the reciprocating speed of the laser is 100~500mm / s; the distance of a single reciprocating motion of the laser is the diameter L of the suture body. c 1 to 3 times.

4. The method for preparing a barbed suture according to claim 1, characterized in that, Glass transition temperature T of the suture body g The temperature ranges from -10°C to 80°C.

5. The method for preparing a barbed suture according to claim 1, characterized in that, The actual value of the barb height h is 90% to 99% of the set value of the barb height h.

6. A barbed suture, characterized in that, The suture is prepared by a method according to any one of claims 1 to 5, comprising a suture body and barbs formed on the suture body.

7. The barbed suture according to claim 6, characterized in that, The barbs are arranged in a spiral direction on the suture body.

8. The barbed suture according to claim 6, characterized in that, The gripping force of the barbs on the barbed suture line is 7.2~10.65N.

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