A sling for treating stress urinary incontinence

Abstract

The application discloses a sling for treating stress urinary incontinence. The sling comprises a sling body, the middle part of the sling body extends to form a fixing arm at both ends, and an expanded polytetrafluoroethylene gasket is fixed to the middle part. The expanded polytetrafluoroethylene gasket comprises a middle area and an edge area, the middle area has a dense structure with a pore size less than 1 micrometer, and the pore size of the edge area gradually increases from the center to 15-30 micrometers. Alternatively, the expanded polytetrafluoroethylene gasket adopts a double-layer structure, comprising a supporting gasket and a bearing gasket, the supporting gasket has a uniform pore size of 15-30 micrometers, and the top surface of the bearing gasket has a dense structure in the middle part and the side surface, and the pore size of the edge area of the top surface gradually increases. According to the application, the dense center area blocks the tissue growth, the gradient edge area eliminates stress concentration, and the supporting gasket reduces the shock and buffering effect, so that the contact pressure peak value and the high-pressure contact area are reduced while the urethra is lifted, the stress concentration caused by the excessively high local pressure is reduced, and the risk of urethra erosion is reduced.

Description

Technical Field

[0001] This invention relates to the field of implantable medical devices, and in particular to a sling for treating stress urinary incontinence. Background Technology

[0002] Male stress urinary incontinence often occurs after radical prostatectomy or transurethral resection of the prostate (TURP), resulting in irreversible damage to the urethral sphincter complex and a significant decrease in urethral closure pressure. When the patient experiences a sudden increase in intra-abdominal pressure due to actions such as coughing, laughing, or lifting heavy objects, the damaged sphincter cannot generate sufficient compensatory closure force, leading to involuntary leakage of urine. Male urinary incontinence slings, as a minimally invasive, passive support implant, have become the preferred treatment for mild to moderate stress urinary incontinence. They restore the physiological coplanar closure of the urethra by lifting the bulbous urethra upwards.

[0003] Chinese patent CN214857827U discloses a urethral sling comprising a mesh, a protective sheath, and a traction line. After the sling is implanted and the protective sheath is removed, the mesh makes direct and continuous mechanical contact with the surrounding tissue. After implantation, the middle portion of the sling directly supports the thin layer of spongy tissue and mucosa on the ventral side of the bulbous urethra. When a patient coughs or lifts heavy objects, causing a sudden increase in abdominal pressure, the sling is instantly tightened and lifted. At this time, the edge of the mesh cuts into the soft urethral wall as a linear tension band. This contact method creates high local pressure and stress concentration, thereby increasing the risk of urethral erosion. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a sling for treating stress urinary incontinence, comprising a sling body, with two ends extending outward to form two symmetrical fixing arms. An expanded polytetrafluoroethylene (ePTFE) pad is fixedly connected to the middle of the sling body. The ePTFE pad has at least one layer structure with a height of 2-4 mm. The ePTFE pad has a top surface that contacts the urethra. The central region of the top surface has a dense structure with a pore size less than 1 μm. The pore size of the edge region of the top surface is larger than that of the central region, and the pore size of the edge region gradually increases from the inside out.

[0005] Furthermore, the expanded polytetrafluoroethylene gasket has a single-layer structure, and the pore size of the edge region gradually increases from the inside to the outside to 15-30 μm.

[0006] In another aspect, the present invention provides that the expanded polytetrafluoroethylene gasket has a double-layer structure, including a support gasket and a load-bearing gasket that wraps around and fixes the support gasket. The top surface of the load-bearing gasket constitutes the top surface, the middle part of the top surface of the load-bearing gasket constitutes the middle region, the edge region of the top surface of the load-bearing gasket constitutes the edge region, and the bottom surface of the support gasket is fixedly connected to the sling body.

[0007] Furthermore, the support pad has a uniform pore size of 15-30 μm, the top center and each side of the bearing pad are dense structures with pore sizes less than 1 μm, and the pore size of the edge region gradually increases from the inside to the outside to 15-30 μm.

[0008] Furthermore, the height of both the support pad and the bearing pad is 1-2 mm.

[0009] Furthermore, the top surface is a concave arc surface.

[0010] Furthermore, the sling body is made of polypropylene mesh.

[0011] Furthermore, a protective sleeve is fitted onto the fixed arm, and a traction line is fixed to the end of the protective sleeve via a heat shrink tubing.

[0012] Furthermore, the expanded polytetrafluoroethylene gasket is fixed to the sling body by heat pressing or sewing.

[0013] Furthermore, the bearing pad is wrapped and fixed around the periphery of the support pad by heat pressing.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] By placing an expanded polytetrafluoroethylene (ePTFE) pad in the middle of the sling body, direct contact between the mesh and the bulbous urethra is avoided. The dense structure in the middle region provides reliable support, while the gradually increasing pore size in the edge region makes the pad edge softer, preventing it from cutting into the urethral wall in the form of a linear tension band. This effectively disperses stress, reduces local pressure, and thus reduces the risk of urethral erosion.

[0016] Furthermore, by setting expanded polytetrafluoroethylene as a double-layer structure of a load-bearing pad and a support pad, the support pad adopts a large-pore structure with uniform pore size (15-30μm), which has good elasticity and can undergo slight deformation when the abdominal pressure rises suddenly to absorb the instantaneous impact force and play a shock-absorbing and buffering role; the top center and sides of the load-bearing pad are dense structures, while the top edge area has a gradient pore radial transition outward, reducing edge stress concentration. Attached Figure Description

[0017] It should be noted that the dimensions, proportions, and aperture sizes of all components shown in the accompanying drawings are illustrative and intended to clearly demonstrate the structural principles and features of the invention, and do not represent the actual proportions or dimensions of a product. The actual scope of protection of this invention is determined by the values ​​and limitations set forth in the claims and specification.

[0018] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the overall structure of another embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of an expanded polytetrafluoroethylene gasket according to an embodiment of the present invention.

[0021] Figure 4 This is a top view of an expanded polytetrafluoroethylene gasket according to an embodiment of the present invention.

[0022] Figure 5 This is a cross-sectional view of an expanded polytetrafluoroethylene gasket according to another embodiment of the present invention.

[0023] Figure 6 This is a schematic diagram of the hierarchical structure of the urethral pressure test according to the present invention.

[0024] Figure 7 This is a schematic diagram of the in vitro simulated urethra structure of the present invention.

[0025] Figure 8 This is a simulated two-dimensional contact pressure distribution diagram in vitro, as shown in Embodiment 1 of the present invention.

[0026] Explanation of the labels in the diagram:

[0027] 1. Sling body; 2. Fixing arm; 3. Expanded PTFE gasket; 31. Central area; 32. Edge area; 33. Supporting gasket; 34. Bearing gasket; 35. Top surface; 4. Protective sleeve; 5. Heat shrink tubing; 6. Traction line; 100. Urethral simulation assembly; 200. Pelvic floor support platform; 300. Abdominal pressure simulation system; 400. Urethral lifting mechanism. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Terminology Explanation:

[0030] Elastic modulus: In this application, it is used to describe the ability of a material to resist tensile or compressive deformation within its elastic range.

[0031] Compressive compliance: refers to the ability of an expanded polytetrafluoroethylene (ePTFE) gasket to undergo elastic compressive deformation along the direction of force when subjected to compressive stress perpendicular to the gasket plane. In this application, the support gasket, due to its uniform large-pore (15–30 μm) sponge-like porous structure, exhibits high compressive compliance because the pore walls can absorb compressive energy through elastic buckling and gradual collapse of the pores under pressure. This characteristic allows the support gasket to undergo slight deformation during a sudden increase in abdominal pressure to buffer the instantaneous impact force, thus playing a shock-absorbing role and reducing the peak stress transmitted to the urethral wall. The level of compressive compliance is related to the pore size, porosity, and intrinsic elastic modulus of the material. Within the pore size range of 15–30 μm, as the pore size increases, the porosity increases, and the compressive compliance increases accordingly.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment provides a sling for treating stress urinary incontinence, including a sling body 1 made of polypropylene large-pore mesh. Two symmetrical fixing arms 2 extend outward from the middle two ends of the sling body 1, and a smooth plastic protective sleeve 4 is fitted on the fixing arm 2. The end of the protective sleeve 4 is fixed with a traction line 6 for surgical puncture guidance through a heat shrink tube 5.

[0034] like Figure 2-3 As shown, an expanded polytetrafluoroethylene (ePTFE) pad 3 is fixedly connected to the middle of the sling body 1 by heat pressing or sewing. Considering the anatomical characteristics of the male body, the bulbar urethra is cylindrical with physiological curvature, and is covered by the bulbospongiosus muscle. To prevent the flat mesh from linearly cutting the urethra, in this embodiment, the top surface of the ePTFE pad 3 (i.e., the side facing the urethra after implantation) is formed as a concave arc surface suitable for conforming to the physiological curvature of the human bulbar urethra.

[0035] like Figure 4As shown, the expanded polytetrafluoroethylene (ePTFE) pad 3 has a height of 2–4 mm and is divided into a central region 31 and surrounding edge regions 32. The central region 31 directly faces the weak area on the ventral side of the bulbous urethra and employs a dense structure with a pore size of less than 1 μm. This dense structure can block the deep ingrowth of macrophages and fibroblasts, avoiding tissue adhesion and thus reducing the risk of sling erosion into the urethra. The pore size of the edge regions 32 gradually increases from 1 μm to 15–30 μm from the central region 31 outwards (the pore size increases by 2–8 μm per millimeter radially), preferably 20 μm. This gradual pore structure causes the elastic modulus of the pad edge to gradually decrease, making the edge softer and avoiding the "stress concentration" cutting effect caused by rigid edges; at the same time, the pore size of 15–30 μm allows for moderate ingrowth of surrounding connective tissue, forming a stable fibrous wrap around the ePTFE pad 3 and preventing the sling from shifting during strenuous patient movement.

[0036] The expanded polytetrafluoroethylene (ePTFE) pad 3 can be prepared by the following method: medical-grade ePTFE resin is extruded as a paste, calendered, and then biaxially stretched at a temperature below its melting point. By controlling the temperature, stretching rate, and stretching ratio of the central and edge regions during the stretching process, a dense structure with a pore size of less than 1 μm is formed in the central region, and a gradient pore size gradually increases from 1 μm to 15-30 μm in the edge region (the pore size increases by 2-8 μm per millimeter radially). The pad is then heat-set to obtain the desired pad. Alternatively, the gradient structure can be formed by hot-pressing and laminating multilayer ePTFE films with different pore sizes. Although this embodiment is described in conjunction with the anatomy of the male bulbar urethra, those skilled in the art will understand that the sling of the present invention is also applicable to the treatment of female stress urinary incontinence, in which case only the top surface shape of the ePTFE pad needs to be adjusted to match the physiological curvature of the female urethra.

[0037] Example 2

[0038] like Figure 2 and Figure 5 As shown, this embodiment provides another sling for treating stress urinary incontinence. The difference from Embodiment 1 is that the expanded polytetrafluoroethylene (ePTFE) pad 3 in this embodiment adopts a "double-layer composite" design, including an inner support pad 33 and an outer load-bearing pad 34.

[0039] Specifically, the bottom surface of the support pad 33 is fixed to the sling body 1, and its overall aperture is uniform (15-30μm), preferably 20μm, with a height of 1-2mm. This large-aperture support pad has good elasticity and compressive resistance, which is equivalent to adding a "shock-absorbing buffer layer" between the mesh and the urethra.

[0040] The support pad 34 is tightly wrapped around the support pad 33 by hot pressing. The support pad 34 is cap-shaped, covering only the top and four sides of the support pad 33, leaving the bottom of the support pad 33 exposed and fixedly connected to the sling body 1. The height of the support pad 34 is 1-2 mm, and its top surface is formed as a concave arc surface. The center of the top surface and the four sides of the support pad 34 are dense structures with pores smaller than 1 μm to block tissue ingrowth; while the pore size of the edge area of ​​the top surface increases outward in a gradient to 15-30 μm, preferably 20 μm (the pore size increases by 2-8 μm per millimeter radially). Both the support pad 33 and the support pad 34 can be made of medical-grade ePTFE using the above-mentioned zoned temperature-controlled stretching process to obtain the corresponding pore sizes. Then, the support pad 34 is fused to the support pad 33 by hot pressing. The total height of the support pad 33 and the load-bearing pad 34 after being stacked is 2-4 mm, which is consistent with the height range of the expanded polytetrafluoroethylene pad in Example 1.

[0041] In this embodiment, when the patient coughs, causing a sudden increase in abdominal pressure, the sling body 1 tightens and rises instantly. At this time, the large-pore sponge-like structure inside the support pad 33 undergoes slight deformation to absorb the instantaneous impact force; simultaneously, the support pad 34 smoothly supports the urethra with its soft gradient edges and concave arc surface. Thus, the elastic deformation of the support pad buffers the instantaneous impact, the dense layer of the support pad blocks tissue ingrowth, and the gradient edges eliminate stress concentration. The sling can therefore stably support the urethra while avoiding severe tissue adhesion and erosion.

[0042] In vitro bulbous urethral contact pressure detection model

[0043] To verify the effectiveness of the sling provided by this invention for treating male stress urinary incontinence, particularly its ability to effectively reduce stress concentration and lower the risk of urethral erosion through the gradually varying pore size design of the expanded polytetrafluoroethylene (ePTFE) pad after elevating the bulbous urethra by 2–3 cm, an in vitro bulbous urethral contact pressure detection model was constructed as follows.

[0044] like Figure 7As shown, the model includes a urethral simulation component (100), a pelvic floor support platform (200), an abdominal pressure simulation system (300), and a sling installation and urethral lifting mechanism (400). The urethral simulation component consists of an inner thin-walled silicone tube and an outer polyvinyl alcohol hydrogel encapsulation, with a total length of 15–20 cm. The inner silicone tube has an inner diameter of 8 mm and a wall thickness of 0.5 mm, used to simulate the soft and collapsible urethral mucosa. The outer polyvinyl alcohol hydrogel is cylindrical, 3–4 mm thick, and tightly wraps the inner silicone tube, with its compressive elastic modulus controlled at 50–100 kPa, used to simulate the composite mechanical properties of the male urethral sponge and its tunica albuginea. Both ends of the urethral simulation component are fixed to the model support, one end being the fixed end, and the other end being connected to a fine-tuning screw that can apply axial pretension to simulate the natural tension state of the urethra in the body. The axial pretension of the urethral simulation component is set to 0.5–1.0 N, applied via a fine-tuning screw to simulate the natural tension state of the urethra within the body. The erosion risk threshold is preset to 30 kPa, meaning areas with contact pressure exceeding 30 kPa are considered high-pressure contact zones.

[0045] The pelvic floor support platform is a rigid base with a U-shaped groove. The width of the U-shaped groove is set to accommodate the urethral simulation component. The surface of the groove is covered with a 5mm thick silicone pad with a Shore A5-10 hardness to simulate the deep soft tissue of the perineum and provide bottom support. The urethral simulation component and support platform are placed in a sealable pressure chamber. An air pump and pressure controller are connected to the outside of the pressure chamber to pressurize the chamber to simulate increased abdominal pressure. The pressure adjustment range is 0-120cmH2O, used to simulate the Valsalva maneuver or the compression of the urethra by abdominal pressure during coughing.

[0046] During testing, the sling to be tested is placed directly below the urethral simulation assembly, with the upper surface of the expanded polytetrafluoroethylene (ePTFE) pad aligned with the bulbous urethral segment to be compressed. The two fixing arms of the sling extend from simulated obturator channels on either side of the U-shaped groove and are symmetrically connected to a high-precision electric displacement stage. A spring of known stiffness (preset to 5–15 N / mm based on the typical stiffness range of the abdominal wall fascia and subcutaneous tissue) is connected in series between each fixing arm and the displacement stage. The displacement stage is first pulled until the urethra is raised by 2 cm or 3 cm, then locked in position. Subsequently, when pressure is applied to the pressure chamber to simulate coughing, the spring is allowed to undergo corresponding passive deformation under abdominal pressure, thus more closely resembling the mechanical boundary conditions of the sling after subcutaneous fixation in clinical practice. This simulates the clinical state of the bulbous urethra being raised by 2 cm and 3 cm during surgery. The simulated closed-hole channel uses two rigid arc-shaped pipes with gradually decreasing inner diameters, extending outward and downward from both sides of the U-shaped groove. The pipe outlet is aligned with the clamp of the electric displacement table to simulate the actual path of the sling passing through the closed hole in the body.

[0047] like Figure 6As shown, a flexible thin-film pressure distribution sensor is pre-fixed between the expanded polytetrafluoroethylene (ePTFE) pad and the outer wall of the urethral simulation component. Its sensing area completely covers the central and edge areas of the pad and extends beyond part of the urethral surface. This sensor can record and generate a two-dimensional pressure distribution map of the contact interface in real time. The flexible thin-film pressure distribution sensor can be a Tekscan I-Scan system or a similar multi-point flexible pressure sensor. It is fixed between the implanted pad and the urethral simulation component using medical pressure-sensitive tape around the perimeter, ensuring that the sensing area is wrinkle-free and does not interfere with the contact interface. Specifically, the pressure range of the flexible thin-film pressure distribution sensor is 0-100 psi (approximately 0-0.69 MPa), and the sensing point density is not less than 248 points / cm². 2 The sensing point spacing is no greater than 0.6 mm. This range fully covers the contact pressure range (0-200 kPa) that this model may generate, and can sensitively capture pressure changes near the preset corrosion risk threshold of approximately 30 kPa. The sensing area size is customized according to the size of the expanded polytetrafluoroethylene gasket.

[0048] When using the above model for comparative verification, the following experimental groups were set up: Group A is the sling of Example 1 of the present invention, whose expanded polytetrafluoroethylene gasket has a dense central region (pore size <1μm) and an edge region where the radial edge of the pores gradually increases to 15-30μm; Group B is the sling of Example 2 of the present invention, whose expanded polytetrafluoroethylene gasket includes a support gasket with a uniform pore size of 15-30μm and a load-bearing gasket wrapped around it. The top center and side of the load-bearing gasket have a dense structure (pore size <1μm), and the pore size of the edge region of the top surface gradually increases from the center to 15-30μm; Group C is the control sling, whose gasket is expanded polytetrafluoroethylene with a uniform pore size, all of which are <1μm or all of which are 15-30μm. Each set of slings was installed and adjusted to the reference positions where the urethra was raised by 2cm and 3cm respectively. Two-dimensional contact pressure distribution maps were recorded under static conditions and under dynamic conditions where the pressure chamber was rapidly pressurized to simulate coughing (the pressure rose to 100cmH2O within 0.1 seconds).

[0049] Evaluation indicators should include at least the coefficient of variation of contact pressure, the maximum pressure value at the edge, the high-pressure contact area ratio, and the urethral compression pattern.

[0050] The coefficient of variation of contact pressure is the ratio of the standard deviation to the average value of the pressure values ​​in the contact area of ​​the gasket. The lower the value, the more uniform the pressure distribution and the less stress concentration.

[0051] The maximum pressure value at the edge is the peak pressure within the edge area of ​​the pad, which is directly related to the risk of urethral erosion.

[0052] The high-pressure contact area ratio is the percentage of the area (A2) where the contact pressure exceeds the preset erosion risk threshold to the total contact area (A1); High-pressure contact area ratio = A2 / A1.

[0053] Urethral compression morphology: Through a miniature endoscope probe placed inside the urethral lumen, the cross-sectional area and closure morphology of the urethral lumen at the compression point of the sling can be observed and measured. Ideal compression should cause the urethra to close gradually and smoothly.

[0054] Based on the above model, the following groups of slings were tested:

[0055] Group A: Embodiment 1 of the present invention: sling (single-layer graded pore size ePTFE gasket, dense structure in the central region with pore size less than 1μm, and pore size in the edge region gradually increasing from 1μm to 15-30μm).

[0056] Group B1: The sling of Embodiment 2 of the present invention has a uniform aperture of 15μm for the support pad and a maximum aperture of 15μm for the top edge area of ​​the bearing pad.

[0057] Group B2: The sling of Embodiment 2 of the present invention has a uniform aperture of 20μm for the support pad and a maximum aperture of 20μm for the top edge area of ​​the bearing pad.

[0058] Group B3: The sling of Embodiment 2 of the present invention has a uniform aperture of 30μm for the support pad and a maximum aperture of 30μm for the top edge area of ​​the bearing pad.

[0059] Group C1: Uniform pore size ePTFE gasket sling, all gasket pore sizes are less than 1μm.

[0060] Group C2: Uniform pore size ePTFE gasket sling, all gasket pores are 20μm.

[0061] Group D: Slings without ePTFE pads, i.e., the polypropylene mesh sling body is in direct contact with the urethral simulation component.

[0062] Verification results

[0063] The tests were conducted under static and simulated dynamic cough conditions, with urethral elevation displacements set at 2 cm and 3 cm. The data trends were consistent across both elevation heights, with more significant differences between groups observed at 3 cm elevation. The following explanation uses typical data from the 3 cm elevation dynamic cough condition as a representative example. The main test results are shown in the table below:

[0064] Table 1. Simulation test results of different slings

[0065] Group Contact pressure variation coefficient Maximum edge pressure (kPa) High-voltage contact area ratio (%) Observation of urethral compression morphology A 0.25±0.03 38±5 12±3 The urethra closes smoothly and gradually, with the closed segment approximately 1.2 cm in length. B1 0.23±0.03 35±4 10±2 The urethra closes smoothly and gradually, with the closed segment approximately 1.3 cm in length. B2 0.22±0.03 31±4 8±2 The urethra closes smoothly and gradually, with the closed segment approximately 1.4 cm in length. B3 0.20±0.03 28±5 7±3 The urethra closes smoothly and gradually, with a closure segment approximately 1.5 cm in length, exhibiting better tissue compliance. C1 0.48±0.06 72±8 35±5 A steep, narrowing ring appears at the edge of the pad, causing the lumen to close abruptly. C2 0.40±0.05 55±6 28±4 The pressure area of ​​the urethra is generally collapsed and soft, but the closure shape is irregular. D 0.65±0.06 96±12 52±7 The urethra shows linear indentations, with visible localized incision-like closures, and the simulated mucosa exhibits obvious folds.

[0066] Under the condition of a 2cm elevation, the coefficient of variation of contact pressure and the maximum edge pressure value of each group were lower than the corresponding values ​​under the condition of 3cm. However, the ranking of the groups was consistent with the table above. The indicators of groups A and groups B1 to B3 were still significantly better than those of the control groups, indicating that the beneficial effects of the present invention can be reflected under different elevation heights.

[0067] Results Analysis

[0068] As can be seen from the results in Table 1, the coefficients of variation of contact pressure in group A and groups B1, B2, and B3 are significantly lower than those in the control groups, indicating that the gradual aperture design provided by the present invention makes the contact pressure distribution more uniform and effectively avoids stress concentration. Figure 8 The diagram shows the two-dimensional contact pressure distribution of group A, revealing that the pressure gradually decreases from the center to the edges. The maximum edge pressure and high-pressure contact area ratio of all three groups of double-layer composite gaskets (B1–B3) were controlled at low levels. Furthermore, as the pore size increased from 15 μm to 30 μm, none of the indicators deteriorated; in fact, compliance showed a slight improvement. This indicates that the expected shock absorption, stress dispersion, and corrosion prevention effects can be achieved in the edge areas of both the support and load-bearing gaskets within the range of 15–30 μm. In contrast, the peak edge pressure of the uniformly compacted gasket (C1) and the gasketless mesh (D) reached as high as 72 kPa and 96 kPa, respectively, with high-pressure contact area ratios of 35% and 52%, far exceeding the corrosion risk threshold. Urethral endoscopy further confirmed that the compression in groups A and B1–B3 caused a smooth, gradual closure of the urethral lumen, while C1 exhibited a steep, cutting-like narrowing ring, and D formed a linear depression, resulting in a significant shearing effect on the urethral wall.

[0069] The above comparison shows that the expanded polytetrafluoroethylene pad of the sling of the present invention, through the dense structure in the central region to block tissue ingrowth, the gradient transition zone at the edge to reduce stress concentration, and the shock absorption and buffering effect of the support pad in the double-layer structure, can provide sufficient lifting to the bulbous urethra while reducing the peak contact pressure and high-pressure contact area, reducing excessive local tissue pressure in the bulbous urethra and thus reducing stress concentration, thereby reducing urethral erosion.

[0070] The above specific embodiments are detailed illustrative examples of the present invention. The scope of the technical solutions covered by these embodiments should be defined by the claims, but is not limited thereto. Any modifications, equivalent substitutions, improvements, etc., made based on the concept of the present invention within the scope of protection of the claims should be included within the scope of protection of the present invention.

Claims

1. A sling for treating stress urinary incontinence, comprising a sling body (1), the sling body (1) comprising a main body portion (11) and two symmetrical fixing arms (2) respectively outwardly extended from two ends of the main body portion (11), characterized in that, The main body (11) is fixedly connected to an expanded polytetrafluoroethylene (PTFE) gasket (3). The expanded polytetrafluoroethylene gasket (3) has at least one layer structure with a height of 2-4 mm. The expanded polytetrafluoroethylene gasket (3) has a top surface (35) that contacts the urethra. The middle region (31) of the top surface (35) has a dense structure with a pore size of less than 1 μm. The pore size of the edge region (32) of the top surface (35) is larger than that of the middle region (31), and the pore size of the edge region (32) gradually increases from the inside to the outside.

2. A sling for the treatment of stress urinary incontinence according to claim 1, characterised in that, The expanded polytetrafluoroethylene gasket (3) has a single-layer structure, and the pore size of the edge region (32) gradually increases from the inside to the outside to 15-30 μm.

3. A sling for treating stress urinary incontinence according to claim 1, characterized in that, The expanded polytetrafluoroethylene gasket (3) has a double-layer structure, including a support gasket (33) and a bearing gasket (34) that is wrapped and fixed around the support gasket (33). The top surface of the bearing gasket (34) constitutes the top surface (35), the middle part of the top surface of the bearing gasket (34) constitutes the middle region (31), the edge region of the top surface of the bearing gasket (34) constitutes the edge region (32), and the bottom surface of the support gasket (33) is fixedly connected to the main body (11).

4. A sling for treating stress urinary incontinence according to claim 3, characterized in that, The support pad (33) has a uniform pore size of 15-30 μm. The top center and each side of the bearing pad (34) are dense structures with a pore size of less than 1 μm. The pore size of the edge region (32) gradually increases from the inside to the outside to 15-30 μm.

5. A sling for treating stress urinary incontinence according to claim 3, characterized in that, The height of both the support pad (33) and the bearing pad (34) is 1-2 mm.

6. A sling for treating stress urinary incontinence according to claim 1 or 3, characterized in that, The top surface (35) is a concave arc surface.

7. A sling for treating stress urinary incontinence according to claim 1 or 3, characterized in that, The sling body (1) is a polypropylene mesh.

8. A sling for treating stress urinary incontinence according to claim 1 or 3, characterized in that, The fixed arm (2) is fitted with a protective sleeve (4), and the end of the protective sleeve (4) is fixed with a traction line (6) through a heat shrink tube (5).

9. A sling for treating stress urinary incontinence according to claim 1 or 3, characterized in that, The expanded polytetrafluoroethylene gasket (3) is fixed to the sling body (1) by hot pressing or sewing.

10. A sling for treating stress urinary incontinence according to claim 3, characterized in that, The bearing pad (34) is wrapped and fixed around the support pad (33) by hot pressing.

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