Medical modified polylactic acid material, preparation method and application thereof, and vascular anastomosis cannula device

Abstract

The invention provides a medical modified polylactic acid material, a preparation method and application thereof and a vascular anastomosis cannula device, and belongs to the field of absorbable materials and microsurgical instruments. The medical modified polylactic acid material is prepared from a polylactic acid copolymer, a hexamethylene diisocyanate tripolymer and an alcohol substance through a modification reaction. According to the invention, the hexamethylene diisocyanate tripolymer and the alcohol substance form a degradable and absorbable polyurethane material in the modification process, and the degradable and absorbable polyurethane material is utilized to modify the polylactic acid to form a cross-linked structure and an interpenetrating network structure, so that the mechanical properties of the polylactic acid can be improved to a great extent; the modified polylactic acid material with excellent mechanical strength, biological and blood compatibility and degradable absorbability is obtained, meanwhile, the contraction function and growth and development of blood vessels are not affected, foreign matter granuloma cannot be formed on outer membranes of the blood vessels, and the problems that a pure polylactic acid material is poor in mechanical property, and the contraction function and growth and development of the blood vessels are affected are solved.

Description

Technical Field

[0001] The invention relates to the technical field of absorbable materials and microsurgical instruments, and in particular to a medical modified polylactic acid material, a preparation method and application thereof, and a vascular anastomosis sleeve device. Background Art

[0002] Microsurgery is an important milestone in the development of surgical technology in the 20th century. Microvascular anastomosis is the technical basis of microsurgery and determines the success or failure of microsurgical repair and reconstruction. According to the anastomosis mechanism, vascular anastomosis technology mainly includes stapler method, magnetic tube method, needle ring method, anastomosis clip method, sleeve method, adhesive anastomosis, etc. The above-mentioned anastomosis devices can simplify the vascular anastomosis process and shorten the vascular anastomosis time, but there are also some defects and shortcomings. For example, the long-term retention of the needle ring in the needle ring method will cause vascular stiffness, affect the normal contraction of the blood vessels and restrict the growth of the blood vessels, and easily form foreign body granulomas in the adventitia of the blood vessels. The anastomosis clip method and the sleeve method can retain the normal vascular wall tissue and ensure the elasticity of the anastomosis, but the non-degradable anastomosis clip residue is still prone to form foreign body granulomas. The sheath method can efficiently anastomose small-caliber blood vessels, ensuring good anastomosis at both ends. The sheath device does not touch the inner wall of the lumen or the blood flow in the lumen. The patency rate after anastomosis is high, the leakage rate is low, and the incidence of postoperative vascular crisis is also low, which has significant advantages.

[0003] Chinese patent CN112294381A discloses a cannula device for microsurgical vascular and lymphatic anastomosis, but the cannula material is polyimide which is difficult to degrade and absorb, and is easy to form foreign body granulomas in the adventitia of the blood vessel. The prior art uses degradable and absorbable materials, such as polylactic acid, to prepare vascular anastomosis devices. After the vascular anastomosis is completed, the anastomosis cannula device is gradually degraded and absorbed in the body, and the degradation products have no obvious adverse effects on the matrix. However, the pure polylactic acid material has a lack of mechanical properties, which affects the contraction function and growth and development of the blood vessels. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a medical modified polylactic acid material and its preparation method and application, and a vascular anastomosis sleeve device. The medical modified polylactic acid material provided by the present invention has excellent mechanical strength, biological and blood compatibility, and degradable absorbability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a medical modified polylactic acid material, which is prepared by a modification reaction of the following raw materials: a polylactic acid copolymer, a hexamethylene diisocyanate trimer (HDI trimer) and an alcohol substance, wherein the alcohol substance comprises polytetramethylene furan diol (PTMG) and 1,4-butanediol.

[0007] Preferably, the molar ratio of the hexamethylene diisocyanate trimer to the alcohol substance is 1.0:1.0 to 1.0:2.0.

[0008] Preferably, the molar ratio of the hexamethylene diisocyanate trimer to the alcohol substance is 1.0:1.2 to 1.0:1.4.

[0009] Preferably, the mass ratio of the polylactic acid copolymer to the modifier is 7:1 to 10:1, and the modifier includes hexamethylene diisocyanate trimer and alcohol substances.

[0010] Preferably, the mass ratio of the polylactic acid copolymer to the modifier is 8:1 to 9:1.

[0011] Preferably, the modification reaction is carried out at a temperature of 150 to 180° C., a pressure of 0.07 to 0.1 MPa, and a time of 0.5 to 2 h.

[0012] The present invention also provides a method for preparing the medical modified polylactic acid material described in the above technical solution, comprising the following steps:

[0013] The polylactic acid copolymer, hexamethylene diisocyanate trimer and alcohol substances are mixed and subjected to modification reaction to obtain the medical modified polylactic acid material.

[0014] The present invention also provides the use of the medical modified polylactic acid material described in the above technical solution in the preparation of microsurgical operating devices.

[0015] The present invention also provides a vascular anastomosis sleeve device, comprising: a first catheter, one end of the first catheter is connected to a second catheter via a connecting sleeve, the outer surface of the connecting sleeve is provided with an annular groove, the outer wall of the second catheter is integrally provided with two annular protrusions, the outer diameter of the first catheter is greater than the outer diameter of the second catheter, the inner diameter of the first catheter is greater than the inner diameter of the second catheter, a handle is provided at one end of the first catheter away from the connecting sleeve, and the materials of the first catheter, the second catheter and the connecting sleeve are independently the medical modified polylactic acid material described in the above technical solution.

[0016] Preferably, the inner diameter of the first conduit is 0.5 mm to 1.0 mm, and the inner diameter of the second conduit is 0.2 to 0.8 mm.

[0017] The invention provides a medical modified polylactic acid material, which is prepared by a modification reaction of the following raw materials: a polylactic acid copolymer, a hexamethylene diisocyanate trimer and an alcohol substance, wherein the alcohol substance comprises polytetramethylene furan diol and 1,4-butanediol.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In the present invention, hexamethylene diisocyanate trimer and alcohol substances form a degradable and absorbable polyurethane material during the modification process, and the degradable and absorbable polyurethane material is used to modify polylactic acid to form a cross-linked structure and an interpenetrating network structure, which can greatly improve the mechanical properties of polylactic acid, and obtain a modified polylactic acid material with excellent mechanical strength, biological and blood compatibility, and degradable absorbability (the degradation and absorption time limit of the medical modified polylactic acid material in the body is 3 to 12 months). The modified polylactic acid material has good biocompatibility and no toxic side effects, can be used for in vivo implantation, can be gradually degraded and absorbed in the body by itself, and does not affect the contraction function and growth and development of blood vessels, nor does it form foreign body granulomas in the adventitia of blood vessels, thereby solving the problem that pure polylactic acid materials have insufficient mechanical properties and affect the contraction function and growth and development of blood vessels.

[0020] The present invention also provides a method for preparing the medical modified polylactic acid material described in the above technical solution, and the reaction conditions are easy to control and industrial-scale production is easy to achieve.

[0021] The present invention also provides a vascular anastomosis sleeve device, which can be customized in batches according to the actual size of the blood vessel, has high cost performance, and the sleeve device does not contact the inner wall of the lumen and the blood flow in the lumen, and can significantly improve the vascular anastomosis patency rate when the anastomosis caliber of the blood vessel ends does not match, thereby meeting the requirements of vascular anastomosis technology in microsurgery.

[0022] Furthermore, the vascular anastomosis sleeve device of the present invention can solve the current problem of small blood vessel anastomosis, overcome the problem of foreign body granulomas formed in the vascular adventitia by non-degradable and absorbable vascular anastomosis devices, and can be efficiently used for in vivo implantation, vascular anastomosis and organ transplantation, etc. The vascular anastomosis sleeve device of the present invention is widely applicable, has a wide application value, and has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the vascular anastomosis sleeve device of the present invention;

[0024] Figure 2 It is a schematic diagram of the vascular anastomosis sleeve device of the present invention being used for vascular anastomosis;

[0025] Figure 3 The cross-sectional morphology scanning electron microscope image of the medical modified polylactic acid material prepared in Example 1;

[0026] Figure 4 Biocompatibility evaluation of the medical modified polylactic acid material prepared in Example 1 - L929 cell viability;

[0027] Figure 5 Biocompatibility evaluation of the medical modified polylactic acid material prepared in Example 1 - NIH3T3 cell viability;

[0028] Figure 6 Biocompatibility evaluation of the medical modified polylactic acid material prepared in Example 1 - RSC96 cell viability. DETAILED DESCRIPTION

[0029] The invention provides a medical modified polylactic acid material, which is prepared by a modification reaction of the following raw materials: a polylactic acid copolymer, a hexamethylene diisocyanate trimer and an alcohol substance, wherein the alcohol substance comprises polytetramethylene furan diol and 1,4-butanediol.

[0030] In the present invention, the molar ratio of the hexamethylene diisocyanate trimer to the alcohol substance is preferably 1.0:1.0 to 1.0:2.0, and more preferably 1.0:1.2 to 1.0:1.4.

[0031] In the present invention, the molar ratio of the polytetrahydrofuran diol to 1,4-butanediol is preferably 4:1 to 10:1, more preferably 5:1 to 7:1, specifically 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1.

[0032] In the present invention, the mass ratio of the polylactic acid copolymer to the modifier is preferably 7:1 to 10:1, more preferably 8:1 to 9:1, and the modifier includes hexamethylene diisocyanate trimer and alcohol substances.

[0033] In the present invention, the polylactic acid copolymer is preferably prepared by a method comprising the following steps:

[0034] The polylactic acid copolymer is obtained by carrying out polycondensation reaction with anhydrous lactic acid as a raw material and stannous octoate as a catalyst.

[0035] In the present invention, the mass ratio of the anhydrous lactic acid to stannous octoate is preferably 1:0.005-0.01, more preferably 1:0.007-0.009, and most preferably 1:0.008.

[0036] In the present invention, the temperature of the polycondensation reaction is preferably 150-180° C., more preferably 160-170° C., the pressure is preferably 0.07-0.1 MPa, more preferably 0.08-0.1 MPa, and the time is preferably 6-10 h, more preferably 7-9 h.

[0037] In the present invention, the temperature of the modification reaction is preferably 150-180°C, more preferably 160-170°C, the pressure is preferably 0.07-0.1 MPa, more preferably 0.08-0.1 MPa, and the time is preferably 0.5-2 h, more preferably 0.5-1 h.

[0038] In the present invention, during the modification reaction, the isocyanate groups on the HDI trimer react with the hydroxyl groups on the PTMG and 1,4-butanediol to obtain polyurethane, and the polyurethane then reacts with the polylactic acid copolymer.

[0039] The present invention also provides a method for preparing the medical modified polylactic acid material described in the above technical solution, comprising the following steps:

[0040] The polylactic acid copolymer, hexamethylene diisocyanate trimer and alcohol substances are mixed and subjected to modification reaction to obtain the medical modified polylactic acid material.

[0041] In the present invention, the parameters of the modification reaction are preferably consistent with the above scheme, which will not be described in detail here.

[0042] The present invention also provides the use of the medical modified polylactic acid material described in the above technical solution in the preparation of microsurgical operating devices.

[0043] The present invention also provides a vascular anastomosis sleeve device, comprising: a first catheter, one end of the first catheter is connected to a second catheter via a connecting sleeve, the outer surface of the connecting sleeve is provided with an annular groove, the outer wall of the second catheter is integrally provided with two annular protrusions, the outer diameter of the first catheter is greater than the outer diameter of the second catheter, the inner diameter of the first catheter is greater than the inner diameter of the second catheter, a handle is provided at one end of the first catheter away from the connecting sleeve, and the materials of the first catheter, the second catheter and the connecting sleeve are independently the medical modified polylactic acid material described in the above technical solution.

[0044] Figure 1 The vascular anastomosis sleeve device of the present invention is a schematic diagram of the structure. Figure 1 The vascular anastomosis cannula device of the present invention will be described.

[0045] The vascular anastomosis sleeve device of the present invention comprises a first catheter.

[0046] In the present invention, the inner diameter of the first conduit is preferably 0.5 mm to 1.0 mm.

[0047] In the present invention, the inner diameter of the second catheter is preferably 0.2-0.8 mm; the function of the second catheter is to facilitate the flipping of the blood vessel and to facilitate the connection of two blood vessels.

[0048] In the present invention, the wall thickness of the first conduit, the second conduit and the connecting sleeve is preferably independently 0.03 to 0.06 mm.

[0049] In the present invention, one end of the connecting sleeve matches the first conduit, and the other end matches the second conduit.

[0050] In the present invention, the total length of the first catheter, the second catheter and the connecting sleeve is preferably 1.0 to 1.5 cm, and the length of each part is preferably set according to actual patient needs.

[0051] In the present invention, the handle portion is preferably arc-shaped, and its maximum inner diameter is the same as that of the first catheter. The cross-sectional circumference of the handle portion is preferably 1 / 2 of the cross-sectional circumference of the first catheter. The function of the handle portion is to provide convenient conditions for clamping the vascular clamp, which is beneficial to the vascular anastomosis operation.

[0052] In the present invention, the inner diameter of the sleeve device is preferably customized according to the actual diameter of the blood vessel to be anastomosed, and can be suitable for anastomosis of blood vessels of different sizes.

[0053] In the present invention, the annular protrusion is used to assist in the inversion of the blood vessel and the fixation of the suture ligation after the sleeve connection.

[0054] Figure 2 The schematic diagram of the vascular anastomosis cannula device of the present invention for vascular anastomosis is shown in FIG. According to the diameter of the blood vessel, the vascular anastomosis cannula device of corresponding size is customized. First, the blood vessel A is inserted into the cannula device, and the first catheter is connected to the second catheter, and sufficient blood vessel length is reserved to facilitate the inversion of the blood vessel A (see FIG. Figure 2 In (a), a single-clip hemostatic clip is used to fix the blood vessel a and the cannula device together and rotated to a suitable angle, and the wall of the blood vessel a is flipped away from the annular protrusion to expose the intima and lumen of the blood vessel a (see Figure 2 (b)); and use a degradable silk thread to tie a knot and fix it, loosen the hemostatic clamp, and then use a double hemostatic clamp to bring the cannula of blood vessel a close to the blood vessel to be anastomosed, and connect the blood vessel to be anastomosed on the cannula device to another annular protrusion, and use a degradable silk thread to tie a knot and fix it at the groove, and loosen the double hemostatic clamp to complete the vascular anastomosis (see Figure 2 (c) and (d)).

[0055] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] Preparation of medical modified polylactic acid materials:

[0058] With anhydrous lactic acid as raw material and stannous octoate as catalyst, the mass ratio of anhydrous lactic acid to stannous octoate is 1:0.008, and the polylactic acid copolymer A is obtained by direct melt polycondensation at 170°C and 0.09MPa for 8 hours; then the polylactic acid copolymer A is melted by heating, and hexamethylene diisocyanate trimer B, polytetrahydrofuran diol C and 1,4-butanediol D are added, wherein the molar ratio of B to alcohol substances (alcohol substances include C and D, and the molar ratio of C to D is 5:1) is 1.0:1.2, and the mass ratio of A to the sum of B+C+D is 9:1. At 170°C and 0.09MPa, the reaction is continued for 1 hour to obtain a medical modified polylactic acid material.

[0059] After testing, compared with polylactic acid, the tensile strength of the prepared medical modified polylactic acid material is 120kg / mm 2 Increased to 265kg / mm 2 , the elongation at break increased from 17% to 60%.

[0060] Figure 3 This is a scanning electron microscope image of the cross-sectional morphology of the medical modified polylactic acid material prepared in Example 1. It can be seen that the prepared medical modified polylactic acid material exhibits ductile fracture behavior.

[0061] A vascular anastomosis sleeve device is prepared using the medical modified polylactic acid material prepared in Example 1, wherein the materials of the first catheter, the second catheter and the connecting sleeve are all the medical modified polylactic acid material prepared in Example 1, and the vascular anastomosis sleeve device comprises a first catheter, one end of the first catheter is connected to the second catheter through a connecting sleeve, an annular groove is provided on the outer surface of the connecting sleeve, and two annular protrusions are integrally provided on the outer wall of the second catheter 2 for fixing the blood vessel, the inner diameter of the first catheter is 0.5 mm, the inner diameter of the second catheter is 0.2 mm, and a handle is provided at one end of the first catheter away from the connecting sleeve, the wall thickness of the first catheter, the connecting sleeve and the second catheter 2 are all 0.06 mm, the handle is arc-shaped, the maximum inner diameter is the same as the maximum inner diameter of the first catheter, and the cross-sectional circumference of the handle is 1 / 2 of the cross-sectional circumference of the first catheter.

[0062] The use process of the vascular anastomosis sleeve device of this embodiment is as follows: customize the sleeve device of corresponding size according to actual needs, first insert blood vessel a into the vascular anastomosis sleeve device, from the first catheter to the second catheter and retain enough blood vessel length to facilitate the flipping of blood vessel a, use a single-clip hemostatic clamp to fix blood vessel a and the vascular anastomosis sleeve device together and rotate to a suitable angle, flip the wall of blood vessel a away from the annular protrusion, expose the inner membrane and lumen of blood vessel a; and use degradable silk thread to tie a knot to fix, and release the hemostatic clamp. Then use a double hemostatic clamp to bring the sleeve of blood vessel a close to the blood vessel to be anastomosed, and connect the blood vessel to be anastomosed on the sleeve device to another annular protrusion, and use a degradable silk thread to tie a knot to fix it at the groove, and release the double hemostatic clamp to complete the vascular anastomosis.

[0063] The degradation and absorption time of the medical modified polylactic acid material prepared in this embodiment in the body is 8 months.

[0064] Biocompatibility test: CCK-8 test was used for biocompatibility test. The cytotoxicity of medical polylactic acid film was tested by co-culturing with L929, NIH3T3 and RSC96 cell lines. The complete growth medium was Dulbecco's modified Eagle's medium (DMEM) (Gibco), supplemented with 10% fetal bovine serum (Gibco), 1.0×10 5 U / L penicillin (Hyclone) and 100mg / L streptomycin (Hyclone) and 250mM L-glutamine. L929, NIH3T3, and RSC96 cells were inoculated in 96-well plates, with a density of 10,000 cells per well for 24 hours, 8,000 cells per well for 48 hours, and 6,000 cells per well for 72 hours, and cultured in a humidified environment containing 5% CO2 and 37°C. After 24 hours of culture, the culture medium was removed and different concentrations of drug-containing copolymer culture medium were added (the drug was sterilized by ultraviolet irradiation for 30 minutes in advance). After 24, 48, and 72 hours, the culture medium was removed, and 100μL of CCK-8 reagent and colorless culture medium (concentration ratio of 1:10) reagent mixture was added to each well, and then placed in an incubator for incubation for 1.5 hours, taken out, and read the plate with a wavelength of 450nm under an ELISA reader. The experiment was repeated 4 times for each group.

[0065] Figure 4 Evaluation of biocompatibility of the medical modified polylactic acid material prepared in Example 1 - L929 cell viability, Figure 5 Biocompatibility evaluation of the medical modified polylactic acid material prepared in Example 1 - NIH3T3 cell viability, Figure 6 The biocompatibility evaluation of the medical modified polylactic acid material prepared in Example 1 - RSC96 cell viability shows that the cell viability of the medical modified polylactic acid material prepared in this example is >85%, and has good biocompatibility.

[0066] Example 2

[0067] Preparation of medical modified polylactic acid materials:

[0068] With anhydrous lactic acid as raw material and stannous octoate as catalyst, the mass ratio of anhydrous lactic acid to stannous octoate is 1:0.008, and the polylactic acid copolymer A is obtained by direct melt polycondensation at 170°C and 0.09MPa for 8 hours; then the polylactic acid copolymer A is melted by heating, and hexamethylene diisocyanate trimer B, polytetrahydrofuran diol C and 1,4-butanediol D are added, wherein the molar ratio of B to alcohol substances (alcohol substances include C and D, and the molar ratio of C to D is 6:1) is 1.0:1.2, and the mass ratio of A to the sum of B+C+D is 9:1, and the reaction is continued at 170°C and 0.09MPa for 1 hour to obtain a medical modified polylactic acid material.

[0069] After testing, compared with polylactic acid, the tensile strength of the prepared medical modified polylactic acid material is 120kg / mm 2 Increased to 189kg / mm 2 , the elongation at break increased from 17% to 57%.

[0070] The medical modified polylactic acid material prepared in Example 2 is used to prepare a vascular anastomosis sleeve device. The structural parameters of the vascular anastomosis sleeve device are the same as those in Example 1. The use process of the vascular anastomosis sleeve device in this example is the same as that in Example 1.

[0071] The degradation and absorption time of the medical modified polylactic acid material prepared in this embodiment in the body is 10 months.

[0072] The biocompatibility test was the same as in Example 1. The test results showed that the cell activity was >85%, indicating that the medical modified polylactic acid material prepared in this example has good biocompatibility.

[0073] Example 3

[0074] Preparation of medical modified polylactic acid materials:

[0075] With anhydrous lactic acid as raw material and stannous octoate as catalyst, the mass ratio of anhydrous lactic acid to stannous octoate is 1:0.01, and the polylactic acid copolymer A is obtained by direct melt polycondensation at 170°C and 0.09MPa for 7 hours; then the polylactic acid copolymer A is melted by heating, and hexamethylene diisocyanate trimer B, polytetrahydrofuran diol C and 1,4-butanediol D are added, wherein the molar ratio of B to alcohol substances (alcohol substances include C and D, and the molar ratio of C to D is 5:1) is 1.0:1.4, and the mass ratio of A to the sum of B+C+D is 7:1. At 170°C and 0.09MPa, the reaction is continued for 1 hour to obtain a medical modified polylactic acid material.

[0076] After testing, compared with polylactic acid, the tensile strength of the prepared medical modified polylactic acid material is 120kg / mm 2 Increased to 203kg / mm 2, the elongation at break increased from 17% to 48%.

[0077] The medical modified polylactic acid material prepared in Example 3 is used to prepare a vascular anastomosis sleeve device. The structural parameters of the vascular anastomosis sleeve device are the same as those in Example 1. The use process of the vascular anastomosis sleeve device in this example is the same as that in Example 1.

[0078] The degradation and absorption time of the medical modified polylactic acid material prepared in this embodiment in the body is 9 months.

[0079] The biocompatibility test was the same as in Example 1. The test results showed that the cell activity was >85%, indicating that the medical modified polylactic acid material prepared in this example has good biocompatibility.

[0080] In summary, the biodegradable and absorbable medical modified polylactic acid material prepared by the present invention has good biocompatibility, no obvious toxicity, does not affect the growth and development of cells, can be used in vivo, and can greatly improve the mechanical properties of polylactic acid.

[0081] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A medical modified polylactic acid material, characterized in that: The invention is prepared by modification reaction of the following raw materials: polylactic acid copolymer, hexamethylene diisocyanate trimer and alcohol substances, wherein the alcohol substances include polytetrahydrofuran diol and 1,4-butanediol.

2. The medical modified polylactic acid material according to claim 1, characterized in that: The molar ratio of the hexamethylene diisocyanate trimer to the alcohol substance is 1.0:1.0 to 1.0:2.

0.

3. The medical modified polylactic acid material according to claim 2, characterized in that: The molar ratio of the hexamethylene diisocyanate trimer to the alcohol substance is 1.0:1.2 to 1.0:1.

4.

4. The medical modified polylactic acid material according to claim 1 or 2, characterized in that: The mass ratio of the polylactic acid copolymer to the modifier is 7:1 to 10:1, and the modifier includes hexamethylene diisocyanate trimer and alcohol substances.

5. The medical modified polylactic acid material according to claim 4, characterized in that: The mass ratio of the polylactic acid copolymer to the modifier is 8:1 to 9:

1.

6. The medical modified polylactic acid material according to claim 1, characterized in that: The modification reaction is carried out at a temperature of 150 to 180° C., a pressure of 0.07 to 0.1 MPa, and a time of 0.5 to 2 hours.

7. The method for preparing the medical modified polylactic acid material according to any one of claims 1 to 6, characterized in that: The following steps are involved: The polylactic acid copolymer, hexamethylene diisocyanate trimer and alcohol substances are mixed and subjected to modification reaction to obtain the medical modified polylactic acid material.

8. Use of the medical modified polylactic acid material according to any one of claims 1 to 6 in the preparation of microsurgical devices.

9. A vascular anastomosis sleeve device, characterized in that: include: A first catheter, one end of the first catheter is connected to a second catheter via a connecting sleeve, an annular groove is provided on the outer surface of the connecting sleeve, two annular protrusions are integrally provided on the outer wall of the second catheter, the outer diameter of the first catheter is greater than the outer diameter of the second catheter, the inner diameter of the first catheter is greater than the inner diameter of the second catheter, a handle is provided at one end of the first catheter away from the connecting sleeve, and the materials of the first catheter, the second catheter and the connecting sleeve are independently the medical modified polylactic acid material according to any one of claims 1 to 6.

10. The vascular anastomosis sleeve device according to claim 9, characterized in that: The inner diameter of the first conduit is 0.5 mm to 1.0 mm, and the inner diameter of the second conduit is 0.2 mm to 0.8 mm.

Images