Device for repairing wound surface after skin grafting or skin flap operation

Abstract

The device comprises a pre-stretching elastic film layer which is sequentially stacked, a gradient drainage layer is arranged below the pre-stretching elastic film layer, and sealing edges are arranged on the outer edges of the pre-stretching elastic film layer and the gradient drainage layer. The sealing edge surrounds the edges of the pre-stretching elastic film layer and the gradient drainage layer and is used for being bonded with the skin to form a closed cavity. Continuous negative pressure is provided through retraction force of the pre-stretched elastic thin film layer, compared with a traditional external pump, the cost is lower, use is more convenient, adhesion with a postoperative wound part is prevented through the arrangement of the anti-adhesion contact layer, and the postoperative wound part is prevented from being damaged. And meanwhile, the anti-adhesion contact layer is provided with a micron-sized bulge array and nano-sized surface textures, so that the anti-adhesion effect is further ensured, and the drainage efficiency is improved through the design of the gradient drainage layer.

Description

Technical Field

[0001] The present invention relates to the technical field of post-skin grafting repair, in particular to a device for repairing wounds after skin grafting or flap surgery. Background Art

[0002] After skin grafting or flap surgery, wound repair is an important clinical issue. The effect of wound recovery directly affects the patient's quality of life, functional recovery and aesthetics. Therefore, it is particularly important to develop effective wound repair devices. Traditional wound treatment methods mainly include the use of dressings, drug application, etc. With the development of biomaterials science, various new biomaterials have been used in wound treatment, such as biocompatible materials, polymer scaffolds and collagen, etc. These materials can provide a microenvironment suitable for cell attachment and growth, and promote wound healing. At present, the market demand for wound repair after skin grafting or flap surgery is increasing, especially in the healing of large-area wounds and chronic wounds.

[0003] However, the existing technology still has major deficiencies, such as: Traditional skin graft or flap postoperative management, manual bandaging, unstable pressure distribution, leading to flap ischemia or edema, damage to new tissue during replacement, increased patient pain, easy blockage of drainage tubes, seroma-induced infection, and existing negative pressure drainage devices (NPWT) rely on electric pumps and sensors, which are expensive and restrict patient activity. Summary of the Invention

[0004] The purpose of the present invention is to provide a device for repairing wounds after skin grafting or flap surgery, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A device for repairing wounds after skin grafting or flap surgery, comprising sequentially stacked pre-stretched elastic film layers, a gradient drainage layer disposed below the pre-stretched elastic film layers, and sealing edges disposed on the outer edges of the pre-stretched elastic film layers and the gradient drainage layer; The sealing edge surrounds the edges of the pre-stretched elastic film layer and the gradient drainage layer and is used to adhere to the skin to form a closed chamber; The gradient drainage layer includes a hydrophobic microporous barrier layer, a hydrophilic liquid storage and drainage layer, and an anti-adhesion contact layer. The hydrophobic microporous barrier layer contacts the bottom of the pre-stretched elastic film layer, the hydrophilic liquid storage and drainage layer is arranged below the hydrophobic microporous barrier layer, and the anti-adhesion contact layer is composed of a hydrophilic microporous layer and directly contacts the wound surface.

[0006] Preferably, the material of the pre-stretched elastic film layer is medical-grade silicone or polyurethane, the thickness is 0.05-0.3 mm, and the pre-stretching rate of the pre-stretched elastic film layer is 180%-250%.

[0007] Preferably, the hydrophobic microporous barrier layer is made of hydrophobically modified polyurethane foam or polypropylene melt-blown non-woven fabric.

[0008] Preferably, the surface of the anti-adhesion contact layer has a bionic micro-nano composite structure, and the anti-adhesion contact layer is provided with a micron-scale protrusion array and a nano-scale surface texture.

[0009] Preferably, the outside of the hydrophilic liquid storage and drainage layer is connected to a liquid storage bag through a drainage tube, and a one-way drainage valve is provided inside the drainage tube.

[0010] Preferably, a biodegradable sustained-release layer is provided between the anti-adhesion contact layer and the wound surface, and the biodegradable sustained-release layer is provided with loaded silver ions or fibroblast growth factor.

[0011] Preferably, the biodegradable sustained-release layer is composed of gelatin microspheres or alginate hydrogel.

[0012] Preferably, the hydrophilic liquid storage and drainage layer comprises longitudinally arranged capillary channels, and the channel diameter of the capillary channels is 100-300 μm.

[0013] Preferably, the pore size of the hydrophobic microporous barrier layer is 50-100 μm, the pore size of the hydrophilic liquid storage and drainage layer is 200-500 μm, and the pore size of the anti-adhesion contact layer is 20-50 μm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Providing continuous negative pressure through the retraction force of the pre-stretched elastic film layer, it is lower in cost and more convenient to use than traditional external pumps; 2. The anti-adhesion contact layer prevents adhesion to the postoperative trauma site. The anti-adhesion contact layer is also equipped with a micron-scale protrusion array and nano-scale surface texture to further ensure the anti-adhesion effect. 3. The design of the gradient drainage layer improves the drainage efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the gradient drainage layer of the present invention; Figure 3 Schematic diagram of the capillary channel of the present invention.

[0016] In the figure: 1. Pre-stretched elastic film layer; 2. Gradient drainage layer; 21. Hydrophobic microporous barrier layer; 221. Capillary channel; 22. Hydrophilic liquid storage drainage layer; 23. Anti-adhesion contact layer; 3. Sealing edge; 4. Drainage tube; 5. Liquid storage bag; 6. One-way drainage valve; 7. Biodegradable sustained-release layer. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] See also Figure 1-3 , the present invention provides a technical solution: A device for repairing wounds after skin grafting or flap surgery, characterized in that: it includes a pre-stretched elastic film layer 1 stacked in sequence, a gradient drainage layer 2 is provided below the pre-stretched elastic film layer 1, and a sealing edge 3 is provided on the outer edges of the pre-stretched elastic film layer 1 and the gradient drainage layer 2. The material of the pre-stretched elastic film layer 1 is medical grade silicone or polyurethane, with a thickness of 0.05-0.3mm, and the pre-stretching rate of the pre-stretched elastic film layer 1 is 180%-250%. The pre-stretched elastic film layer 1 in this embodiment adopts medical grade silicone or polyurethane with a thickness of 0.1mm, and is pre-stretched 180%-250% in one direction or two directions during manufacturing. Overheating and shaping are performed for fixed deformation. After covering the wound, a continuous negative pressure of 5-15kPa is generated due to elastic retraction. This structure forms the core frame of the closed negative pressure chamber. The pre-stretched elastic film layer 1 provides the power source, the gradient drainage layer 2 realizes the directional management of the liquid, and the sealing edge 3 ensures the airtightness of the chamber. The three work together to replace the traditional electric negative pressure device and realize passive operation. When the thickness of the pre-stretched elastic film layer 1 is less than 0.05mm, the negative pressure generated by the insufficient retraction force is less than 5kPa, and the wound flap cannot be effectively fitted. When the thickness is greater than 0.3mm, the elastic modulus is too high, resulting in a local pressure peak greater than 40kPa, which may cause ischemia.

[0019] The sealing edge 3 surrounds the edges of the pre-stretched elastic film layer 1 and the gradient drainage layer 2 and is used to adhere to the skin to form a closed chamber; The gradient drainage layer 2 includes a hydrophobic microporous barrier layer 21, a hydrophilic liquid storage drainage layer 22 and an anti-adhesion contact layer 23. The hydrophobic microporous barrier layer 21 contacts the bottom of the pre-stretched elastic film layer 1, and the hydrophilic liquid storage drainage layer 22 is arranged below the hydrophobic microporous barrier layer 21. The anti-adhesion contact layer 23 is composed of a hydrophilic microporous film and directly contacts the wound surface. The high contact angle of the hydrophobic microporous barrier layer 21 is greater than 110°, forming an anti-reflux valve, and using capillary tension to prevent liquid from flowing back to the wound surface. The hydrophilic liquid storage drainage layer 2 quickly absorbs and temporarily stores exudate through high porosity and hydrophilic groups. The anti-adhesion contact layer 23 adopts a microporous structure of 20-50μm to balance air permeability and isolation, and physically prevent granulation tissue from embedding.

[0020] The hydrophobic microporous barrier layer 21 is made of hydrophobically modified polyurethane foam or polypropylene melt-blown non-woven fabric. The hydrophobic microporous barrier layer 21 uses hydrophobically modified polyurethane foam to achieve chemical hydrophobicity through fluorination modification. The microporous structure of 50-100μm enhances capillary repulsion. If polypropylene melt-blown non-woven fabric is used, the fibers are randomly stacked to form a physical hydrophobic barrier, which reduces costs and can be sterilized at high temperatures.

[0021] The surface of the anti-adhesion contact layer 23 has a bionic micro-nano composite structure. The anti-adhesion contact layer 23 is provided with a micron-scale protrusion array and a nano-scale surface texture. The bionic anti-adhesion principle is adopted here. The micron-scale protrusion array has a diameter of 20μm and a height of 40μm, which reduces the wound contact area by 78% and can inhibit fibroblast attachment. The nano-scale surface texture is 200nm deep, forming an air cushion effect, causing the exudate to roll down in a spherical shape, thereby reducing cell adhesion and greatly reducing the risk of dressing change injury.

[0022] The outside of the hydrophilic liquid storage and drainage layer 22 is connected to a liquid storage bag 5 through a drainage tube 4. A one-way drainage valve 6 is provided inside the drainage tube 4. A split drainage structure is adopted here to avoid the valve body being integrated into the dressing: to prevent the increase of dressing, the thickness affecting the fitting force and local pressure concentration, the one-way drainage valve 6 threshold is 1.5-3kPa, and it is opened only when the liquid storage layer is saturated, that is, the hydraulic pressure is greater than the threshold, to prevent negative pressure leakage. The liquid storage bag 5 adopts transparent capacity visualization, which is convenient for medical staff to quantitatively evaluate the exudate.

[0023] A biodegradable sustained-release layer 7 is provided between the anti-adhesion contact layer 23 and the wound surface. Silver ions or fibroblast growth factor are loaded on the biodegradable sustained-release layer 7. The biodegradable sustained-release layer 7 is composed of gelatin microspheres or alginate hydrogels. The gelatin microspheres degrade within 3 days under the action of proteases and are suitable for antibacterial purposes during acute inflammation. The alginate hydrogel releases slowly for 7 days as the calcium ion concentration changes, matching the granulation tissue hyperplasia cycle. The silver ion loading is 0.5 mg / cm², which can kill 99% of Staphylococcus aureus with the lowest cytotoxicity.

[0024] The hydrophilic liquid storage drainage layer 22 includes longitudinally arranged capillary channels 221, and the channel diameter of the capillary channels 221 is 100-300 μm. The channel size of the capillary channels 221 in this embodiment is optimized based on fluid dynamics. If the diameter is less than 100 μm, the channel is easily blocked by protein, and if it is greater than 300 μm, the capillary effect fails. The capillary channels 221 are arranged longitudinally and use gravity to assist the liquid to flow in a directional manner toward the drainage tube 4.

[0025] The pore size of the hydrophobic microporous barrier layer 21 is 50-100 μm, the pore size of the hydrophilic liquid storage and drainage layer 22 is 200-500 μm, and the pore size of the anti-adhesion contact layer 23 is 20-50 μm.

[0026] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A device for wound repair after skin grafting or flap surgery, characterized by: It comprises pre-stretched elastic film layers (1) stacked in sequence, a gradient drainage layer (2) is provided below the pre-stretched elastic film layer (1), and sealing edges (3) are provided at the outer edges of the pre-stretched elastic film layer (1) and the gradient drainage layer (2); The sealing edge (3) surrounds the edges of the pre-stretched elastic film layer (1) and the gradient drainage layer (2) and is used to adhere to the skin to form a closed chamber; The gradient drainage layer (2) comprises a hydrophobic microporous barrier layer (21), a hydrophilic liquid storage and drainage layer (22) and an anti-adhesion contact layer (23), wherein the hydrophobic microporous barrier layer (21) contacts the lower portion of the pre-stretched elastic film layer (1), the hydrophilic liquid storage and drainage layer (22) is arranged below the hydrophobic microporous barrier layer (21), and the anti-adhesion contact layer (23) is composed of a hydrophilic microporous film and directly contacts the wound surface.

2. The device for wound repair after skin grafting or flap surgery according to claim 1, characterized in that: The material of the pre-stretched elastic film layer (1) is medical-grade silicone or polyurethane, with a thickness of 0.05-0.3 mm, and the pre-stretching rate of the pre-stretched elastic film layer (1) is 180%-250%.

3. The device for wound repair after skin grafting or flap surgery according to claim 2, characterized in that: The hydrophobic microporous barrier layer (21) is made of hydrophobically modified polyurethane foam or polypropylene melt-blown non-woven fabric.

4. The device for wound repair after skin grafting or flap surgery according to claim 3, characterized in that: The surface of the anti-adhesion contact layer (23) has a bionic micro-nano composite structure, and the anti-adhesion contact layer (23) is provided with a micron-scale protrusion array and a nano-scale surface texture.

5. The device for wound repair after skin grafting or flap surgery according to claim 1, characterized in that: The outside of the hydrophilic liquid storage and drainage layer (22) is connected to a liquid storage bag (5) via a drainage tube (4), and a one-way drainage valve (6) is provided inside the drainage tube (4).

6. The device for wound repair after skin grafting or flap surgery according to claim 1, characterized in that: A biodegradable slow-release layer (7) is provided between the anti-adhesion contact layer (23) and the wound surface, and the biodegradable slow-release layer (7) is provided with loaded silver ions or fibroblast growth factor.

7. The device for wound repair after skin grafting or flap surgery according to claim 6, characterized in that: The biodegradable sustained-release layer (7) is composed of gelatin microspheres or alginate hydrogel.

8. The device for wound repair after skin grafting or flap surgery according to claim 1, characterized in that: The hydrophilic liquid storage and drainage layer (22) comprises longitudinally arranged capillary channels (221), and the channel diameter of the capillary channels (221) is 100-300 μm.

9. The device for wound repair after skin grafting or flap surgery according to claim 1, characterized in that: The pore size of the hydrophobic microporous barrier layer (21) is 50-100 μm, the pore size of the hydrophilic liquid storage and drainage layer (22) is 200-500 μm, and the pore size of the anti-adhesion contact layer (23) is 20-50 μm.

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