Intestinal weight loss stent

Abstract

The application discloses an intestinal weight-reducing stent, which comprises a covered sleeve and a mesh positioning section. The covered sleeve is provided with double-layer composite covering film, the outer layer of which is a non-degradable film with multiple through holes, and the inner layer of which is a degradable film with multiple through holes, and the pore size of the through holes of the outer layer is larger than that of the inner layer. The mesh positioning section is provided with multiple types of optional auxiliary positioning structures, which can greatly reduce the risk of tissue damage during removal while ensuring stable anchoring. The intestinal weight-reducing stent realizes dynamic controllable weight-reducing effect, stable implantation and safe removal, and provides an effective minimally invasive solution for obesity treatment.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an intestinal weight loss stent that can be implanted in the human intestine to partially block nutrient absorption through physical means to achieve weight loss. Background Technology

[0002] An intestinal weight loss stent is an effective, minimally invasive, and reversible interventional weight loss device. It is temporarily placed in the duodenum, and the stent's cannula isolates the intestine from food, thereby reducing the duodenum's absorption of nutrients and achieving reversible weight loss.

[0003] Existing intestinal weight loss stents have the following drawbacks: First, the intestinal weight loss stent uses a metal mesh or sleeve structure, and the direct contact area between the stent body and the intestinal wall is too large, resulting in a strong foreign body sensation. Secondly, effective fixation and safe removal are difficult to achieve simultaneously. To ensure secure fixation, intestinal stents often employ rigid barbs, which can easily damage intestinal tissue during removal, inevitably leading to bleeding and perforation. To address this, some improved intestinal stents have adopted a gentle, wall-hugging design, relying solely on their own elastic expansion force for fixation. However, these devices are prone to displacement due to intestinal peristalsis and chyme flushing, which can range from affecting the treatment effect to causing obstruction in the distal intestine.

[0004] Third, existing intestinal weight loss stents have a single function and cannot achieve dynamic and adaptive adjustment of weight loss intensity. This is because the blocking efficiency of existing intestinal weight loss stents is fixed and cannot adapt to the different nutritional needs of individuals at different stages of weight loss. For example, during the rapid weight loss phase, highly efficient blocking of nutrient absorption is needed to quickly initiate weight loss; during the plateau phase, a moderate increase in nutrition is needed to overcome metabolic adaptation; and during the maintenance phase, more nutrient absorption is needed to establish long-term balance. Therefore, although existing intestinal weight loss stents are effective in the early stages of weight loss, they often lead to metabolic shocks and malnutrition during the plateau and maintenance phases over time.

[0005] In summary, there is an urgent need in this field for an intestinal weight loss stent with minimal foreign body sensation that can achieve stable and trauma-controlled anchoring in the key absorption site of the duodenum, can be safely, completely, and easily removed after treatment, and allows the stent's nutrient barrier function to adaptively adjust over time to simulate the physiological weight loss process, thereby improving the safety of treatment and user experience. Summary of the Invention

[0006] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides an intestinal weight loss stent to solve the technical problems mentioned in the background art.

[0007] In one aspect, the present invention provides an intestinal weight loss stent, comprising: a covered sheath and a mesh positioning segment connected to each other; the mesh positioning segment is positioned in the duodenal bulb and includes a mesh body, a retrieval hook, and an auxiliary positioning structure, wherein the retrieval hook and the auxiliary positioning structure are disposed on the mesh body, and the diameter of the mesh body is larger than the diameter of the covered sheath; the covered sheath is positioned in the duodenum and includes a spiral wire stent with a double-layer composite sheath on its surface, the double-layer composite sheath including an outer non-degradable sheath and an inner degradable sheath, the outer non-degradable sheath having a plurality of outer through holes, and the inner degradable sheath having a plurality of inner through holes at positions corresponding to the plurality of outer through holes, the outer through holes and the inner through holes having the same shape, the diameter of the outer through holes being larger than the diameter of the inner through holes before degradation, and the outer through holes and the inner through holes at least partially overlapping.

[0008] Furthermore, the diameter of the outer layer through-hole is 1.0-2.5 mm, and the diameter of the inner layer through-hole before degradation is 0.2-0.8 mm.

[0009] Furthermore, the total surface area of ​​the outer layer through-holes accounts for 20%-40% of the total surface area of ​​the double-layer composite coating; the total surface area of ​​the inner layer through-holes before degradation accounts for 10%-20% of the total surface area of ​​the double-layer composite coating.

[0010] Furthermore, the auxiliary positioning structure includes a positioning retaining ring and positioning spikes, with biodegradable bio-adhesive filling the space between the retaining ring and the spikes. The longitudinal cross-section of the positioning retaining ring is T-shaped, and the retaining ring has a cylindrical base and a flange perpendicular to the axis of the base. The retaining ring is axially fixed to the metal wire of the mesh body through the cylindrical base. The positioning spikes have a pointed portion and an abutting portion. The pointed portion extends obliquely outward from the surface of the mesh body, and the abutting portion is an annular elastic element with a notch. The notch is smaller than the diameter of the cylindrical base. The end of the pointed portion is fixed at the middle position of the abutting portion, and the abutting portion elastically hugs the cylindrical base and abuts against the flange. The auxiliary positioning structure is configured such that circumferential relative movement can occur between the positioning spikes and the positioning retaining ring after the bio-adhesive is completely degraded. When the intestinal weight loss stent is removed, the positioning spikes and the positioning retaining ring can be separated.

[0011] Furthermore, the auxiliary positioning structure includes an integrally formed spike portion and a spiral winding portion. The spike portion extends obliquely outward from the surface of the mesh body, and the spiral winding portion is fixed on the metal wire of the mesh body.

[0012] Furthermore, the auxiliary positioning structure includes a spike portion and a biodegradable fixing portion. The spike portion is fixed to the mesh body by the biodegradable fixing portion and extends obliquely outward from the surface of the mesh body. The auxiliary positioning structure is configured to allow the spike portion to separate from the mesh body when the intestinal weight loss stent is removed, and to allow the spike portion to remain in the intestine.

[0013] Furthermore, the auxiliary positioning structure has a spike perpendicular to the surface of the mesh body and two support arms that extend obliquely outward from the surface of the mesh body. Each support arm has an inverted V-shaped bend for abutting against the intestinal wall.

[0014] Furthermore, the distance between the tip of the inverted V-shaped bend and the mesh body is greater than the distance between the tip of the spike and the mesh body.

[0015] Furthermore, the end of the mesh positioning section away from the film-coated sleeve is provided with an annular flange, the diameter of which is larger than the diameter of the mesh body.

[0016] Furthermore, both ends of the mesh positioning segment are provided with the annular flange.

[0017] The intestinal weight loss stent provided by this invention has the following beneficial effects: (1) The spiral metal wire structure has excellent longitudinal flexibility and can bend naturally with intestinal peristalsis, avoiding local rigid compression. The double-layer composite membrane on the surface provides a smooth biocompatible interface, which greatly reduces the direct friction between the metal wire and the intestinal wall mucosa. As the inner biodegradable membrane gradually degrades, the rigidity of the scaffold is further reduced slowly, making its mechanical properties closer to the surrounding soft tissue, which significantly improves the long-term tolerance of patients.

[0018] (2) Through the double-layer membrane design with large pores inside small pores, in the early stage of intestinal weight loss stent implantation, the inner membrane with small pores mainly forms a high barrier state, realizing rapid weight loss initiation; as the inner membrane degrades, the effective pore size gradually increases, the nutrient absorption rate rises slowly, the weight loss speed transitions naturally, avoiding metabolic shock and malnutrition during the plateau and maintenance periods, and realizing controllable weight loss process management.

[0019] (3) Through a variety of auxiliary positioning structures set on the mesh positioning segment, the intestinal weight loss stent can provide immediate and reliable radial support and axial anti-displacement capability in the early stage of implantation, and can also achieve safe separation of the anchoring component from the stent body through bio-adhesive degradation and structural separation when it is removed, which greatly reduces the risk of tearing damage to the intestinal wall when it is removed.

[0020] (4) The stent is divided into a covered sheath and a mesh positioning segment, which precisely correspond to the anatomical features of the duodenal tube and the duodenal bulb, respectively. The difference in diameter and the design of the annular flange form a natural physical barrier to prevent the stent from migrating distally. Attached Figure Description

[0021] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the intestinal weight loss stent provided in one embodiment of this application in the implanted state; Figure 2 This is a schematic diagram of a non-implantable intestinal weight loss stent provided in another embodiment of this application. Figure 1 ; Figure 3 This is a schematic diagram of a non-implantable intestinal weight loss stent provided in another embodiment of this application. Figure 2 ; Figure 4 This is a schematic diagram of an auxiliary positioning structure provided in another embodiment of this application. Figure 1 ; Figure 5 This is a schematic diagram of an auxiliary positioning structure provided in another embodiment of this application. Figure 2 ; Figure 6 This is a schematic diagram of an auxiliary positioning structure provided in another embodiment of this application. Figure 3 ; Figure 7 This is a schematic diagram of an auxiliary positioning structure provided in another embodiment of this application. Figure 4 ; Figure 8 This is a schematic diagram of an annular flange provided in another embodiment of this application.

[0022] Figure label: 1-Covered sheath; 11-Helical wire support; 12-Double-layer composite coating; 121-Outer layer through-hole; 122-Inner layer through-hole; 2-Mesh positioning segment; 21-Mesh body; 22-Removal hook; 23-Auxiliary positioning structure; 231-Positioning retaining ring; 231a-Base; 231b-Flange; 232-Positioning spike; 232a-Spike portion; 232b-Abutting portion; 233-Spike portion; 234-Helical winding portion; 235-Degradable fixing portion; 236-Vertical spike portion; 237-Supporting arm; 237a-Inverted V-shaped bend portion; 24-Annular flange; 100-Duodenum; 101-Duodenal bulb; 102-Stomach; 103-Pylorus. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In this embodiment, the term "proximal" refers to the end closer to the surgeon, and "distal" refers to the end further away from the surgeon.

[0025] See Figure 1 One embodiment of this application provides an intestinal weight loss stent, which includes an interconnected covered sheath 1 and a mesh positioning segment 2. The covered sheath 1 is positioned within the duodenum 100, and its special covered structure is a core component for performing nutrient barrier function. The mesh positioning segment 2 is positioned in the duodenal bulb 101, i.e., the region between the duodenum 100 and the pylorus 103, and its main function is to anchor the stent to prevent it from slipping into the distal small intestine and to provide an extraction interface.

[0026] The mesh positioning segment 2 includes a mesh body 21, a retrieval hook 22, and an auxiliary positioning structure 23. The mesh body 21 is preferably woven from metal wires with superelasticity and / or shape memory effect, such as nickel-titanium alloy. In its free state, it is tubular, with a diameter designed to be slightly larger than the intestinal diameter of the target implantation site, so that it can adhere to the intestinal wall by radial expansion force after release, providing basic fixation. The retrieval hook 22 is fixed to the front end of the mesh body 21 (near the pylorus), facilitating grasping by interventional instruments (such as snares) and providing a point of leverage for subsequent retrieval operations. The auxiliary positioning structure 23 is arranged on the mesh body 21 in various forms to enhance anchoring stability; its specific implementation will be detailed below. The diameter of the mesh body 21 is designed to be larger than the diameter of the covered sheath 1. This dimensional difference allows the stent to form a stepped structure at the junction of the duodenal bulb 101 and the duodenum 100, effectively resisting axial displacement forces generated by intestinal peristalsis and downward erosion of chyme.

[0027] The covered cannula 1 consists of a spiral wire scaffold 11 and a double-layer composite membrane 12 covering its surface. The spiral wire scaffold 11 can also be made of nickel-titanium alloy wire. Its spiral structure gives the scaffold good longitudinal flexibility, allowing it to adapt to intestinal curvature while maintaining sufficient radial support to keep the lumen patent. Furthermore, the spiral wire scaffold 11 has a smaller contact area with the intestinal wall compared to traditional cannulas or mesh scaffolds. These characteristics of the spiral wire scaffold 11 greatly reduce direct friction between the wire and the intestinal mucosa, making its mechanical properties closer to those of the surrounding soft tissue, reducing the patient's foreign body sensation, and significantly improving long-term patient tolerance.

[0028] See Figure 2 and Figure 3 The double-layer composite membrane 12 is composed of an outer non-degradable membrane and an inner degradable membrane. The outer non-degradable membrane is preferably a medical polymer material with excellent biocompatibility and stable mechanical properties, such as silicone rubber, expanded polytetrafluoroethylene (ePTFE), or polyurethane (PU). The inner degradable membrane is preferably a medical polymer material that can be hydrolyzed or enzymatically broken down in vivo, such as polylactic acid (PLA), polycaprolactone (PCL), or their copolymers (PLGA). The two membranes are tightly bonded together using a biocompatible adhesive lamination, hot pressing, or microspinning technology.

[0029] Furthermore, the outer non-degradable membrane has multiple outer through-holes 121, preferably distributed regularly and uniformly. The inner degradable membrane has inner through-holes 122 of the same shape but smaller diameter at the position corresponding to each outer through-hole 121. The through-holes on the two membranes at least partially overlap, preferably completely overlap, thus forming a composite channel with large pores surrounding smaller pores. In the initial implantation stage, the inner degradable membrane is intact, and chyme must pass through the inner through-holes 122 and the outer through-holes 121 sequentially to contact the intestinal wall. At this time, the effective pore diameter of the composite channel is equal to the pore diameter of the inner through-hole 122 (typically set to 0.2-0.8 mm), forming a fine sieve. It effectively blocks most solid components of chyme containing incompletely digested proteins and fat particles (mostly ranging in size from tens of micrometers to 2 mm), allowing only water, pancreatic and biliary digestive juices, electrolytes, vitamins, and a small amount of very small molecule nutrients to pass through. This transforms the dangerous blocking of chyme in the initial stages of weight loss into controlled screening, achieving both rapid initiation of weight loss and ensuring initial effectiveness, while also achieving safe weight loss and higher patient tolerance. In contrast, existing technologies use completely non-porous intestinal cannulas, which not only essentially completely isolate chyme but also essentially block the flow of digestive juices such as bile and pancreatic juice, as well as the absorption of basic electrolytes and water, posing high clinical risks and being unacceptable for long-term tolerance.

[0030] As implantation time progresses, the inner biodegradable membrane begins to degrade at a predetermined rate. The degradation process starts with molecular chain breakage, potentially leading to membrane thinning, dissolution and expansion of the pore edges, until the localized membrane completely disappears – this process is gradual. As the inner pores 122 enlarge, the effective pore size of the composite channel also gradually increases, steadily improving the intestinal absorption rate of nutrients. This precisely matches the nutritional needs of the plateau phase in the weight loss process; that is, a moderate increase in nutrient supply during the plateau phase helps stabilize the basal metabolic rate, preventing a decline in metabolic adaptation caused by prolonged excessive restriction, thus helping to break through the weight loss bottleneck. Once the inner biodegradable membrane is completely degraded, the effective pore size of the composite channel becomes the pore size of the outer pores 121 (usually set at 1.0-2.5 mm). At this point, larger chyme particles can pass through, and the intestinal absorption rate of nutrients reaches its peak. This stage precisely matches the nutritional needs of the maintenance phase in the weight loss process; that is, during the maintenance phase, only moderately restricted nutrient absorption supports the body in establishing a new, sustainable energy balance after reaching the target weight, effectively preventing weight rebound. Therefore, the double-layered membrane with large pores enclosing small pores enables an intelligent transition in the weight loss process from forced intervention to physiological coordination, which is more in line with the body's natural regulatory laws.

[0031] It should be noted that setting the pore size of the outer through-hole 121 to 1.0-2.5 mm and the pore size of the inner through-hole 122 to 0.2-0.8 mm is scientifically based on the size of the duodenal villi (approximately 0.5-1.5 mm) and the distribution of chyme particles. Since most of the inner pores are smaller than the villi diameter, they can effectively cover the villi tips; while most of the outer pores are larger than the villi diameter, which is sufficient to ensure the passage of chyme fluid.

[0032] Furthermore, for severely obese individuals who need to lose weight quickly, a biodegradable inner layer membrane with a smaller inner pore size and slower degradation can be selected, for example, an inner pore size of 0.2 mm; for moderately obese individuals, a biodegradable inner layer membrane with a slightly larger inner pore size and faster degradation can be selected, for example, an inner pore size of 0.5 mm; and for mildly obese individuals, a biodegradable inner layer membrane with the largest inner pore size and fastest degradation can be selected.

[0033] Furthermore, the total surface area of ​​the outer layer through-holes 121 accounts for 20%-40% of the total surface area of ​​the double-layer composite membrane 12; and the total surface area of ​​the inner layer through-holes 122 accounts for 10%-20% of the total surface area of ​​the double-layer composite membrane 12. This through-hole density range ensures sufficient nutrient barrier effect while retaining the necessary nutrient flow area, achieving a balance between weight loss speed and basic nutritional safety for the human body.

[0034] Optionally, the outer through-hole 121 and the inner through-hole 122 can be either circular holes (e.g., ...). Figure 2 As shown), it can also be a rectangular hole (such as...).Figure 3 (As shown), it can also be other shapes that are easy to process.

[0035] See Figures 4-7 In order to enable the intestinal weight loss stent to provide immediate and reliable radial support and axial anti-displacement capability in the early stage of implantation, and to be easily removed without damaging the intestinal wall, another embodiment of this application has designed several auxiliary positioning structures for the intestinal weight loss stent. The auxiliary positioning structures are different from the barbs or barbs fixed on the cannula or stent in the prior art, and can achieve reversible anchoring of the stent body.

[0036] (1) Separable retaining ring-anchoring spike structure See Figure 4In this embodiment, the auxiliary positioning structure 23 includes a positioning retaining ring 231 and a positioning spike 232. The longitudinal section of the positioning retaining ring 231 is T-shaped, with a cylindrical base 231a and a disc-shaped flange 231b perpendicular to the axis of the base 231a. The positioning retaining ring 231 is fitted and fixed (e.g., by laser welding or bonding) to a metal wire of the mesh body 21 through its base 231a. The flange 231b serves to support and limit movement. The positioning spike 232 has a spike portion 232a and an abutment portion 232b. The spike portion 232a extends obliquely outward from the surface of the mesh body 21 (the direction of extension is consistent with the direction of chyme transport in the intestine), and its end is designed as a sharp tip to facilitate penetration into the intestinal wall mucosa. The abutment portion 232b is a notched annular elastic element (or a C-shaped structure), with the notch slightly smaller than the diameter of the cylindrical base 231a. The end of the spike 232a is fixed in the middle position of this semi-annular structure. The positioning spike 232 is elastically engaged with the cylindrical base 231a of the positioning retaining ring 231 by the elastic semi-annular abutment portion 232b, and the end face of the abutment portion 232b abuts against the flange 231b of the positioning retaining ring 231. This connection method allows the positioning spike 232 to be restricted radially, but allows for a certain degree of movement in the circumferential direction. The gap between the base 231a of the positioning retaining ring 231 and the abutment portion 232b of the positioning spike 232, or around both, is filled with biodegradable bio-adhesive. The biodegradable bioadhesive is initially in a cured state, firmly bonding the positioning spike 232 to the positioning retaining ring 231, ensuring that the anchoring force is effectively transferred from the stent body to the positioning spike 232, thereby penetrating the intestinal wall to provide strong initial anchoring. After several weeks to months, the biodegradable bioadhesive has largely degraded in the intestinal fluid environment. At this point, the adhesive force between the positioning spike 232 and the positioning retaining ring 231 disappears, and it is only suspended on the base 231a by the semi-circular abutment part 232b, forming a semi-movable connection. When the weight loss is completed and the stent needs to be removed, the doctor pulls the weight loss stent by removing the hook 22. The axial tension on the positioning spike 232 causes its abutment part 232b to slide or rotate relative to the base 231a of the retaining ring, thereby tilting the spike part 232a from its original insertion direction and withdrawing it from the intestinal wall tissue in a slipping manner rather than a forced pull. This greatly reduces the risk of tissue tearing and bleeding. In extreme cases, if a positioning spur 232 is slightly tightly wrapped by tissue, the movable connection allows the positioning spur 232 to completely separate from the retaining ring 231 when the stent body is removed, thus safely leaving the positioning spur 232 in the body. Since the positioning spur 232 is usually made of thin, biocompatible metal wire (such as nickel-titanium alloy wire) and penetrates to a very shallow depth, it either remains in the body and integrates with the intestinal wall cells, or is subsequently carried out of the body by food, further ensuring the safety of the stent removal procedure.

[0037] (2) Spiral winding fixing structure See Figure 5In this embodiment, the auxiliary positioning structure 23 is integrally molded and includes a spike portion 233 and a spiral winding portion 234. The spike portion 233 extends obliquely outward from the surface of the mesh body 21 (extending in the direction of food flow within the intestine). The spiral winding portion 234 is tightly wound around one or more metal wires of the mesh body 21 like a spring, thereby achieving fixation. More preferably, the spiral winding portion 234 is movably connected to one or more metal wires of the mesh body 21. When the support body undergoes slight shape changes due to intestinal peristalsis or food passage, the movably connected spiral winding portion 234 allows the spike portion 233 integrally formed with it to slide or rotate slightly relative to the metal wires of the mesh body 21. This avoids rigidly transmitting the stress generated by local deformation to the spike portion that has pierced the intestinal wall, thereby preventing fatigue fracture of the spike root due to repeated bending and reducing the risk of continuous prying or cutting damage to the intestinal wall tissue caused by the spike. When the stent is removed, the helical winding portion 234 of the movable connection can slide or rotate relative to the axial traction force applied by the physician. This allows the anchoring puncture to more easily transition from an insertion position to a smooth withdrawal position, significantly reducing the likelihood of hooking and tearing intestinal wall tissue. Compared to fixation methods that require precision welding or bonding, this winding and movable connection method is simpler to manufacture, lower in cost, and reduces reliance on heat-affected zones or adhesive biocompatibility, thereby improving the overall reliability and consistency of the product.

[0038] (3) Biodegradable adhesive fixing structure See Figure 6 The auxiliary positioning structure 23 in this embodiment includes a spike portion 235a and a biodegradable fixing portion 235. The root of the spike portion 235a is bonded and fixed to the metal wire of the mesh body 21 through the biodegradable fixing portion 235. The material of the biodegradable fixing portion 235 can be similar to that of the inner biodegradable coating, such as polylactic acid, polycaprolactone, etc. In the early stage of implantation of the intestinal weight loss stent, the solidified biodegradable fixing portion 235 firmly fixes the spike portion 235a to the stent, providing anchoring force to the intestinal wall. When it is necessary to remove it, the biodegradable fixing portion 235 has been completely or partially degraded, and the connection strength between the spike portion 235a and the stent body is greatly weakened or disappeared. The spike portion 235a is very easy to separate from the stent body and remain in the body. The spike portion 235a remaining in the body is gradually wrapped by fibrous tissue, becoming a harmless foreign body, or is gradually carried out of the body with the peristalsis of food in the intestine.

[0039] (4) V-shaped spike composite support structure See Figure 7The auxiliary positioning structure 23 of this embodiment has a composite form, including a vertical spike 236 perpendicular to the surface of the mesh body 21, and two support arms 237 extending obliquely outward from the surface of the mesh body 21. Each support arm 237 ends in an inverted V-shaped bend 237a, the tip of which abuts against the intestinal wall. This is a hybrid anchoring mechanism combining insertion and support. Under the radial expansion force of the support, the two oblique support arms 237 and their inverted V-shaped bends 237a compress the intestinal wall, creating a localized depression and generating significant frictional resistance, thus providing the primary anti-displacement capability. The vertical spike 236 provides auxiliary insertion anchoring. Notably, the distance L1 between the tip of the inverted V-shaped bend 237a and the surface of the mesh body 21 is designed to be greater than the distance L2 between the tip of the vertical spike 236 and the surface of the mesh body 21.

[0040] During stent implantation and release, the inverted V-shaped bend 237a of the support arm 237 first contacts and compresses the intestinal wall, establishing initial stability, followed by the vertical spike 236 piercing the intestinal mucosa. This design avoids the spike penetrating the intestinal wall at the outset; the support arm 237 provides a distributed compressive contact surface, which is more resistant to the periodic peristalsis of the intestine than a single spike. More importantly, the contact point of the inverted V-shaped bend 237a is more prominent than that of the vertical spike 236, bearing the main load and reducing the penetration depth and stress of the vertical spike to some extent, thus lowering the risk of excessively deep puncture leading to difficult removal. When the stent is removed, the vertical spike 236 is easier to withdraw due to its shallower penetration into the intestinal wall, while the support arm 237 is also easier to detach due to compression rather than penetration.

[0041] See Figure 8 To further enhance anti-migration capabilities, an additional annular flange 24 is provided at one end of the mesh positioning segment 2. The diameter of the annular flange 24 is larger than the diameter of other areas of the mesh body 21. More preferably, annular flanges 24 are provided at both the proximal and distal ends of the mesh positioning segment 2. This annular flange 24 is equivalent to adding two radially larger protrusions to the anchoring segment of the stent. When the stent is in the ideal position, the annular flange 24 at the front end is engaged between the duodenal bulb 101 and the pylorus 103, while the annular flange 24 at the rear end is engaged at the junction of the duodenal bulb 101 and the duodenal tube, forming a double embedding effect, which greatly enhances axial stability. Even in the event of minor displacement, the flanges can more easily hook onto the folds of the intestinal wall, achieving rapid re-anchoring and preventing catastrophic long-distance displacement. This design significantly improves the long-term positional stability of the stent in the complex intestinal environment and is an important safety mechanism to prevent stent failure and displacement, especially suitable for patients with active intestinal peristalsis.

[0042] The clinical operation procedure of the intestinal weight loss stent of the present invention is as follows: The doctor inserted a compressed intestinal stent into a delivery catheter. Under X-ray fluoroscopy and endoscopic guidance, the delivery catheter was advanced through the mouth and esophagus to the stomach, and then further advanced until its tip passed through the pylorus 103 and entered the duodenum.

[0043] After precise positioning, the outer sheath of the delivery catheter is slowly retracted, and the stent gradually expands and unfolds. The mesh positioning segment 2 unfolds and anchors in the duodenal bulb 101, and the covered cannula 1 unfolds within the duodenal intestinal tract.

[0044] Post-surgery, the patient ate normally. After food was digested into chyme in the stomach, it was selectively filtered by the double-layer composite membrane 12 as it flowed through the covered cannula 1, reducing nutrient absorption and leading to gradual weight loss. The doctor can conduct regular follow-ups based on the weight loss progress and the patient's condition.

[0045] When the expected weight loss goal is reached or treatment needs to be terminated, the removal hook 22 is located through the endoscope, and after being grasped with a snare, the entire stent or its main part is gently removed through the mouth.

[0046] The above description is merely a preferred embodiment of the present invention. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to the specific combination of the above-described technical features, but should also cover other technical solutions formed by any combination of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. An intestinal weight loss stent, characterized in that, include: Interconnected coated sleeves and mesh positioning sections; The mesh positioning segment is positioned in the duodenal bulb and includes a mesh body, a removal hook, and an auxiliary positioning structure. The removal hook and the auxiliary positioning structure are disposed on the mesh body, and the diameter of the mesh body is larger than the diameter of the covered sheath. The covered tube is positioned inside the duodenum and includes a spiral metal wire support with a double-layer composite coating on its surface. The double-layer composite coating includes an outer non-degradable coating and an inner degradable coating. The outer non-degradable coating has multiple outer through holes, and the inner degradable coating has multiple inner through holes at positions corresponding to the multiple outer through holes. The outer and inner through holes have the same shape, and the diameter of the outer through holes is larger than the diameter of the inner through holes before degradation. The outer and inner through holes at least partially overlap.

2. The intestinal weight loss stent according to claim 1, characterized in that, The outer layer through-hole has a diameter of 1.0-2.5 mm, and the inner layer through-hole has a diameter of 0.2-0.8 mm before degradation.

3. The intestinal weight loss stent according to claim 2, characterized in that, The total surface area of ​​the outer layer through-holes accounts for 20%-40% of the total surface area of ​​the double-layer composite coating; the total surface area of ​​the inner layer through-holes before degradation accounts for 10%-20% of the total surface area of ​​the double-layer composite coating.

4. The intestinal weight loss stent according to claim 1, characterized in that: The auxiliary positioning structure includes a positioning retaining ring and a positioning spike, and the space between the positioning retaining ring and the positioning spike is filled with biodegradable bio-adhesive. The longitudinal section of the positioning retaining ring is T-shaped. The positioning retaining ring has a cylindrical base and a flange perpendicular to the axis of the base. The positioning retaining ring is axially fixed to the metal wire of the mesh body through the cylindrical base. The positioning spike has a spike and abutment. The spike extends obliquely outward from the surface of the mesh body. The abutment is an annular elastic member with a notch. The notch is smaller than the diameter of the cylindrical base. The end of the spike is fixed in the middle of the abutment. The abutment elastically hugs the cylindrical base and abuts against the flange. The auxiliary positioning structure is configured such that when the bio-adhesive is completely degraded, circumferential relative movement can occur between the positioning spikes and the positioning retaining ring; when the intestinal weight loss stent is removed, the positioning spikes and the positioning retaining ring can be separated.

5. The intestinal weight loss stent according to claim 1, characterized in that: The auxiliary positioning structure includes an integrally formed spike and a spiral winding portion. The spike extends obliquely outward from the surface of the mesh body, and the spiral winding portion is fixed on the metal wire of the mesh body.

6. The intestinal weight loss stent according to claim 1, characterized in that: The auxiliary positioning structure includes a spike and a biodegradable fixing part. The spike is fixed to the mesh body by the biodegradable fixing part and extends obliquely outward from the surface of the mesh body. The auxiliary positioning structure is configured to allow the spike to separate from the mesh body when the intestinal weight loss stent is removed, and to allow the spike to remain in the intestine.

7. The intestinal weight loss stent according to claim 1, characterized in that: The auxiliary positioning structure has a spike perpendicular to the surface of the mesh body and two support arms that extend obliquely outward from the surface of the mesh body. Each support arm has an inverted V-shaped bend for abutting against the intestinal wall.

8. The intestinal weight loss stent according to claim 7, characterized in that: The distance between the tip of the inverted V-shaped bend and the mesh body is greater than the distance between the tip of the spike and the mesh body.

9. The intestinal weight loss stent according to claim 1, characterized in that, The end of the mesh positioning section away from the film-coated sleeve is provided with an annular flange, the diameter of which is larger than the diameter of the mesh body.

10. An intestinal weight loss stent according to claim 9, characterized in that, Both ends of the mesh positioning section are provided with the annular flange.

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