3D printing tracheal stent and preparation method thereof

Abstract

The application discloses a 3D printing tracheal stent and a preparation method thereof. The stent comprises a plurality of meridional units and a plurality of weft units. The meridional unit is composed of a first meridional connecting segment, a second meridional connecting segment and a meridional inner convex elastic segment connecting the two. The weft unit is composed of a first weft connecting segment, a second weft connecting segment and a weft inner convex elastic segment connecting the two. A plurality of meridional units are sequentially connected in series along different meridional directions to form a plurality of meridional chains, which are arranged in a circumferential interval. A plurality of weft units are respectively connected between adjacent meridional chains to form a columnar mesh stent together with the meridional chains. The geometric-mechanical coupling characteristics of the meridional inner convex elastic segment and the weft inner convex elastic segment realize the decoupling of the stent support and compliance functions, and fundamentally eliminate the mechanical root cause of the stent displacement.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a 3D-printed tracheal stent and its preparation method. Background Technology

[0002] Tracheal stents are an important treatment for malignant or benign tracheal stenosis, tracheomalacia, tracheoesophageal fistula, and other diseases. By implanting a stent into the narrowed segment of the airway through interventional procedures, airway patency can be rapidly restored, improving patients' respiratory distress symptoms. Currently, commonly used tracheal stents in clinical practice are mainly divided into metallic stents (such as nickel-titanium shape memory alloy stents) and silicone stents, with structural forms including straight-tube and Y-shaped bifurcated types.

[0003] However, existing tracheal stents still present many technical challenges in clinical practice. Among these, stent displacement is one of the most common complications. The trachea undergoes complex axial expansion, radial dilation, and circumferential torsion during physiological activities such as breathing, coughing, and swallowing. Traditional stents, often monolithic structures with uniform stiffness distribution, cannot respond to deformations in different areas. When the trachea elongates axially, the stent is stretched, leading to relative displacement and shear forces between the stent and the tracheal wall. Over time, this can cause progressive stent displacement or even detachment.

[0004] The root of the problem lies in the fact that existing stent designs cannot simultaneously meet the dual requirements of "high radial support force" and "high axial compliance". Pursuing radial support force results in a rigid stent with poor compliance, easily damaging the mucosa; pursuing axial compliance results in a soft stent with insufficient anchoring force, easily displaced. In other words, current technology cannot achieve stable decoupling of radial support and axial compliance functions, leading to a risk of stent displacement after placement.

[0005] Therefore, it is of great significance to develop a tracheal stent that can provide stable radial support and autonomously adapt to the physiological deformation of the trachea. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention discloses a 3D printed tracheal stent and its preparation method, which can solve or at least alleviate one or more of the above-mentioned problems or other problems existing in the prior art.

[0007] This invention discloses a 3D-printed tracheal stent, comprising:

[0008] Multiple warp units, each warp unit including a first warp connecting segment, a second warp connecting segment, and a warp inward convex elastic segment connecting the first warp connecting segment and the second warp connecting segment; and

[0009] Multiple latitudinal units, each latitudinal unit including a first latitudinal connecting segment, a second latitudinal connecting segment, and a latitudinal inwardly convex elastic segment connecting the first latitudinal connecting segment and the second latitudinal connecting segment;

[0010] Among them, multiple meridional units are connected in series along different longitude directions to form multiple meridional chains, and the multiple meridional chains are arranged at intervals in the circumferential direction; multiple latitudinal units are respectively connected between two adjacent meridional chains, and the multiple meridional chains and multiple latitudinal units are interconnected to form a columnar grid support.

[0011] Both the meridional inward convex elastic segment and the latitudinal inward convex elastic segment protrude radially inward toward the columnar grid support, and are independently configured such that when the trachea deforms, through their own elastic deformation, they respectively drive the corresponding first meridional connecting segment, second meridional connecting segment, first latitudinal connecting segment and second latitudinal connecting segment to move synchronously with the inner wall of the trachea, so as to avoid relative sliding between each connecting segment and the inner wall of the trachea.

[0012] Compared with existing technologies, this invention constructs a columnar grid support with bidirectional mechanical decoupling capability through the array arrangement of warp and weft units. The warp inward convex elastic segment is responsible for absorbing axial expansion and contraction deformation, while the weft inward convex elastic segment is responsible for absorbing circumferential expansion and contraction deformation. The two work together to enable the support to achieve "follow-up displacement" in multiple motion dimensions, fundamentally eliminating the relative sliding between the support and the tracheal wall and significantly reducing the risk of displacement.

[0013] Preferably, the radially convex elastic segment is a single-turn helical spring, with its two ends connected to the first radial connecting segment and the second radial connecting segment, respectively.

[0014] The radially convex elastic section of the present invention adopts a single-turn helical spring. By utilizing the inherent geometric-mechanical coupling characteristics of the helical spring, which reduces the coil diameter when stretched axially and expands the coil diameter when compressed axially, the first and second radial connecting sections are respectively moved in accordance with the tracheal wall.

[0015] Preferably, the radially convex elastic segment includes two single-turn helical springs and a straight segment; the first ends of the two single-turn helical springs are respectively connected to the first radial connecting segment and the second radial connecting segment, and the second ends of the two single-turn helical springs are respectively connected to the two ends of the straight segment.

[0016] This invention employs a symmetrical structure with two single-turn helical springs connected in series by a straight segment, which can achieve a more uniform stress distribution under axial load. The straight segment also serves as a limiting function, allowing the stent to smoothly transition stiffness when subjected to high impact loads such as coughing, thus avoiding impact damage to the tracheal wall caused by sudden mechanical changes.

[0017] Preferably, the radially convex elastic segment includes a three-quarter turn helical spring segment, an arc segment, a straight segment, and a curved segment connected in sequence; the first radial connecting segment is connected to the starting end of the three-quarter turn helical spring segment, and the second radial connecting segment is connected to the end of the curved segment away from the straight segment; and the straight segment and the arc segment are located radially inside the first radial connecting segment.

[0018] This invention utilizes a three-quarter-turn helical spring segment combined with arc-shaped and straight segments to create a spatially discontinuous layout (including axially collinear / non-collinear intervals) between the first and second radial connecting segments. The corresponding tracheal inner wall regions of each segment do not overlap, nor do they have overlapping points or segments in their projections. When the trachea in the first radial connecting segment region deforms, this spatial arrangement prevents the deformation from directly causing synchronous movement of the second radial connecting segment. This ensures that the three-quarter-turn helical spring segment can independently absorb deformation, achieving mechanical decoupling between the first and second radial connecting segments. This solution further eliminates the kinematic coupling between the first and second radial connecting segments, achieving a more thorough mechanical decoupling, and is particularly suitable for applications with significant localized tracheal deformation.

[0019] Preferably, the radially convex elastic segment includes two three-quarter turn helical spring segments, two arc segments, and a straight segment; the first ends of the two three-quarter turn helical spring segments are respectively connected to the first radial connecting segment and the second radial connecting segment, the second ends of the two three-quarter turn helical spring segments are respectively connected to one end of the two arc segments, the other ends of the two arc segments are connected to each other through the straight segment, and the straight segment and the arc segment are located radially inside the first radial connecting segment.

[0020] This invention employs two symmetrically arranged three-quarter-turn helical spring segments, interconnected by arc-shaped and straight segments to form a "double-spring-rigid linkage" structure. The two three-quarter-turn helical spring segments extend from the first and second meridional connecting segments towards the center, respectively, and are interconnected by arc-shaped and straight segments. This creates a spatially discontinuous arrangement between the first and second meridional connecting segments, with no overlap in their projection areas on the trachea's inner wall. When deformation occurs on either side of the trachea, the three-quarter-turn helical spring segment on that side independently absorbs the deformation, while the middle straight segment acts as a limiter and load transfer mechanism, ensuring that the deformation absorption on both sides does not interfere with each other. Compared to a single-sided spring structure, the symmetrical arrangement of the double springs results in a more balanced mechanical response and a more uniform load distribution, making it particularly suitable for applications with large axial spacing between connecting segments or requiring bidirectional symmetrical follow-up.

[0021] Preferably, the convex elastic segment in the weft direction is a single-turn helical spring, with its two ends connected to the first weft connecting segment and the second weft connecting segment, respectively.

[0022] The latitudinal convex elastic section of the present invention adopts a single-turn helical spring. By utilizing the inherent geometric-mechanical coupling characteristics of the helical spring, which reduces the coil diameter when stretched axially and expands the coil diameter when compressed axially, the first latitudinal connecting section and the second latitudinal connecting section are respectively moved in accordance with the tracheal wall.

[0023] Preferably, the latitudinal inward convex elastic segment includes two single-turn helical springs and a straight segment; the first ends of the two single-turn helical springs are respectively connected to the first latitudinal connecting segment and the second latitudinal connecting segment, and the second ends of the two single-turn helical springs are respectively connected to the two ends of the straight segment.

[0024] This invention employs a symmetrical structure with two single-turn helical springs connected in series via a straight segment. This structure achieves a more uniform stress distribution under axial loads, while the straight segment also acts as a limiting element, ensuring a smooth transition in stiffness when the stent is subjected to high impact loads such as coughing, thus preventing abrupt mechanical changes that could damage the tracheal wall. When the same dual-spring series structure is used in both the longitudinal and latitudinal directions, the stent exhibits symmetrical mechanical response characteristics in both the axial and circumferential directions, simplifying design complexity and ensuring consistent movement across different directions.

[0025] Preferably, the latitudinal inward convex elastic segment includes a three-quarter turn helical spring segment, an arc segment, a straight segment, and a curved segment connected in sequence; the first latitudinal connecting segment is connected to the starting end of the three-quarter turn helical spring segment, and the second latitudinal connecting segment is connected to the end of the curved segment away from the straight segment; and the straight segment and the arc segment are located radially inside the first latitudinal connecting segment.

[0026] This invention employs the same three-quarter turn helical spring structure in the latitudinal convex elastic section as in the meridional convex elastic section, thus enabling the support to possess the same spatial arrangement and mechanical decoupling capability in the circumferential (latitudinal) direction. When the trachea undergoes circumferential expansion or contraction deformation, the corresponding tracheal inner wall regions of the first and second latitudinal connecting sections do not overlap in projection, effectively preventing the transmission of circumferential deformation of the trachea between the first and second latitudinal connecting sections. This achieves independent deformation absorption in both meridional and latitudinal directions, further enhancing the displacement decoupling performance of the columnar grid support in multiple motion dimensions.

[0027] Preferably, the latitudinal inward convex elastic segment includes two three-quarter turn helical spring segments, two arc segments, and a straight segment; the first ends of the two three-quarter turn helical spring segments are respectively connected to the first latitudinal connecting segment and the second latitudinal connecting segment, the second ends of the two three-quarter turn helical spring segments are respectively connected to one end of the two arc segments, the other ends of the two arc segments are connected to each other through the straight segment, and the straight segment and the arc segment are located radially inside the first latitudinal connecting segment.

[0028] This invention employs the same double three-quarter turn helical spring symmetrical structure in the latitudinal inward convex elastic segment as in the meridional inward convex elastic segment, thereby enabling the stent to possess the mechanical decoupling capability of bilateral symmetrical arrangement in the circumferential (latitudinal) direction. When the trachea undergoes circumferential expansion or contraction deformation, the spring segments on both sides independently absorb the deformation, while the straight segment in the middle ensures that the follow-up displacements on both sides are not coupled, and simultaneously ensures that the tracheal inner wall regions corresponding to each circumferential connecting segment do not have overlapping projections. The double three-quarter turn helical spring symmetrical structure in both the meridional and latitudinal directions gives the stent symmetrical and balanced mechanical properties in the axial and circumferential directions, making it particularly suitable for complex anatomical locations such as the tracheal carina that require highly adaptable follow-up movements in multiple directions.

[0029] A method for fabricating a tracheal stent using 3D printing as described above includes the following steps:

[0030] Step S1: Obtain three-dimensional anatomical data of the patient's trachea;

[0031] Step S2: Based on the three-dimensional anatomical data, establish a three-dimensional model of the columnar mesh support composed of the meridional units and the latitudinal units, and determine the structural parameters of each unit structure;

[0032] Step S3: Import the three-dimensional model into the 3D printing system;

[0033] Step S4: Using biodegradable polymer materials, a tracheal stent is obtained by integral molding through fused deposition modeling 3D printing technology.

[0034] This invention utilizes 3D printing to eliminate structurally weak areas such as weld points and connectors, resulting in a gradual surface erosion degradation mode rather than brittle fracture, significantly reducing the risk of sharp fragments falling off. The biodegradable polymer material allows the stent to safely disappear after fulfilling its mechanical support function (6-24 months), eliminating the need for a second surgery for removal, and can also serve as a drug delivery carrier.

[0035] The present invention has the following beneficial effects:

[0036] This technical solution constructs a columnar grid support with bidirectional mechanical decoupling capability through the array arrangement of meridional and latitudinal units. The meridional inward convex elastic segment is responsible for absorbing axial expansion and contraction deformation, while the latitudinal inward convex elastic segment is responsible for absorbing circumferential expansion and contraction deformation. The two work together to enable the support to achieve "follow-up displacement" in multiple motion dimensions, fundamentally eliminating the relative sliding between the support and the tracheal wall and significantly reducing the risk of displacement. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of this disclosure, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0038] Figure 1 This is a schematic diagram of the tracheal stent in Embodiment 1 of the present invention;

[0039] Figure 2 This is a schematic diagram of the warp chain and weft unit in Embodiment 1 of the present invention;

[0040] Figure 3 This is a schematic diagram of the tracheal stent in Embodiment 2 of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the warp chain and weft unit in Embodiment 2 of the present invention;

[0042] Figure 5 This is a schematic diagram of the meridional unit in Embodiment 2 of the present invention;

[0043] Figure 6 This is a schematic diagram of the tracheal stent in Embodiment 3 of the present invention;

[0044] Figure 7 This is a schematic diagram of the warp chain and weft unit in Embodiment 3 of the present invention;

[0045] Figure 8 This is a schematic diagram of the structure of the warp and weft units in Embodiment 3 of the present invention;

[0046] Figure 9 This is a schematic diagram of the tracheal stent in Embodiment 4 of the present invention;

[0047] Figure 10 This is a schematic diagram of the warp chain and weft unit in Embodiment 4 of the present invention;

[0048] Figure 11 This is a schematic diagram of the structure of the warp and weft units in Embodiment 4 of the present invention;

[0049] Figure 12 This is a schematic diagram of the tracheal stent in Embodiment 5 of the present invention;

[0050] Figure 13 This is a schematic diagram of the warp chain and weft unit in Embodiment 5 of the present invention;

[0051] Figure 14 This is a schematic diagram of the structure of the warp and weft units in Embodiment 5 of the present invention;

[0052] Figure 15 A photograph of the tracheal stent prepared according to the present invention;

[0053] Figure 16 This is a simulation stress cloud diagram of axial tension based on a physical tracheal stent, as presented in this invention.

[0054] Figure 17 This is a force-displacement curve diagram based on the axial tensile simulation of a tracheal stent in this invention.

[0055] Figure 18 This is a lateral compression simulation stress cloud diagram based on a physical tracheal stent, as presented in this invention.

[0056] Figure 19 This is a force-displacement curve diagram based on the lateral compression simulation of a tracheal stent in this invention. Detailed Implementation

[0057] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods.

[0058] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0059] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0060] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0061] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] Example 1

[0064] like Figure 1-2 As shown, the 3D-printed tracheal stent of this embodiment includes multiple meridional units 11 and multiple latitudinal units 12.

[0065] The warp unit 11 includes a first warp connecting segment 111, a second warp connecting segment 112, and a warp-oriented inwardly convex elastic segment 113 connecting the first warp connecting segment 111 and the second warp connecting segment 112. The weft unit 12 includes a first weft connecting segment 121, a second weft connecting segment 122, and a weft-oriented inwardly convex elastic segment 123 connecting the first weft connecting segment 121 and the second weft connecting segment 122. The cross-sections of the warp unit 11 and the weft unit 12 can be circular or rectangular, or other cross-section shapes can be selected according to actual conditions.

[0066] Multiple meridional units 11 are connected in series along different longitude directions to form multiple meridional chains, which are arranged at intervals in the circumferential direction. Specifically, multiple meridional units 11 are connected in series along the same longitude direction (i.e., along the same axial line of the long axis of the trachea); in two adjacent meridional units, the first meridional connecting segment 111 of one meridional unit is directly connected to the second meridional connecting segment 112 of the adjacent meridional unit. In this way, multiple meridional units 11 are continuously connected along the axial direction to form a complete meridional chain; the multiple meridional chains are arranged at intervals in the circumferential direction to form the longitudinal skeleton of the stent.

[0067] Multiple latitudinal units 12 are connected between two adjacent longitudinal chains, and the longitudinal chains and latitudinal units 12 are interconnected to form a columnar grid support. Specifically, latitudinal units 12 are set up for lateral connection between two adjacent longitudinal chains in the circumferential direction; the first latitudinal connecting segment 121 of the latitudinal unit 12 connects to a longitudinal unit 11 on one of the longitudinal chains, and its second latitudinal connecting segment 122 connects to a longitudinal unit on the other adjacent longitudinal chain. In this way, the latitudinal units 12 connect adjacent longitudinal chains to each other, forming a stable grid structure together with the longitudinal chains.

[0068] Furthermore, in this embodiment, the specific location of the connecting nodes has been optimized. For example... Figure 2 As shown, between two adjacent warp chains, the first latitudinal connecting segment 121 of the latitudinal unit 12 can be connected to the first warp connecting segment 111 or the second warp connecting segment 112 of the warp unit on one warp chain, or to the connection point between two adjacent warp units; its second latitudinal connecting segment 122 can be correspondingly connected to the first warp connecting segment 111 or the second warp connecting segment 112 of the warp unit on another warp chain, or to the connection point between two adjacent warp units. These various connection methods can be selected according to the local mechanical requirements of the support or the optimization of the printing path, all of which can achieve reliable fixation between the latitudinal unit and the warp chain.

[0069] In this embodiment, both the longitudinally convex elastic segment 113 and the latitudinally convex elastic segment 123 protrude radially inward toward the columnar grid support, and are independently configured such that when the trachea deforms, through their own elastic deformation, they drive the corresponding first longitudinal connecting segment 111, second longitudinal connecting segment 112, first latitudinal connecting segment 121 and second latitudinal connecting segment 122 to move synchronously with the inner wall of the trachea, so as to avoid relative sliding between each connecting segment and the inner wall of the trachea.

[0070] When the meridional inward convex elastic segment 113 and the latitudinal inward convex elastic segment 123 are designed to bulge radially inward toward the columnar mesh stent, after the columnar mesh stent is placed into the patient's trachea, neither the meridional inward convex elastic segment 113 nor the latitudinal inward convex elastic segment 123 directly contacts the inside of the trachea. When the trachea deforms, the inner wall of the trachea causes the first meridional connecting segment 111, the second meridional connecting segment 112, the first latitudinal connecting segment 121, and the second latitudinal connecting segment 122 to move slightly or follow the movement. The meridional inward convex elastic segment 113 and the latitudinal inward convex elastic segment 123 will undergo corresponding deformation to avoid relative sliding of the first meridional connecting segment 111, the second meridional connecting segment 112, the first latitudinal connecting segment 121, and the second latitudinal connecting segment 122 relative to the inner wall of the trachea, which significantly reduces the risk of stent displacement.

[0071] When the meridional inward convex elastic segment 113 and the latitudinal inward convex elastic segment 123 are designed to bulge radially inward toward the columnar mesh stent, neither of them directly contacts the inner wall of the trachea after the stent is placed in the patient's trachea. When the trachea deforms, the inner wall of the trachea causes the first meridional connecting segment 111, the second meridional connecting segment 112, the first latitudinal connecting segment 121, and the second latitudinal connecting segment 122 to undergo follow-up displacement, while the meridional inward convex elastic segment 113 and the latitudinal inward convex elastic segment 123 undergo corresponding deformation to avoid relative sliding of each connecting segment relative to the inner wall of the trachea, thereby significantly reducing the risk of stent displacement.

[0072] In this embodiment, in order to ensure that the meridional inward convex elastic segment 113 has excellent elastic deformation and recovery capabilities, the meridional inward convex elastic segment 113 adopts a single-turn helical spring 113a (i.e., a single-turn spring structure), and its two ends are respectively connected to the first meridional connecting segment 111 and the second meridional connecting segment 112.

[0073] In one embodiment, both the first meridional connecting segment 111 and the second meridional connecting segment 112 include straight segments and curved segments; wherein, the straight segment of the first meridional connecting segment 111 is connected to one end of the single-turn helical spring 113a through its curved segment, and the straight segment of the second meridional connecting segment 112 is connected to the other end of the single-turn helical spring 113a through its curved segment; the straight segments of the first meridional connecting segment 111 and the straight segments of the second meridional connecting segment 112 have the same axial centerline, and this axial centerline is parallel to the axial centerline of the support. In another embodiment, both the first meridional connecting segment 111 and the second meridional connecting segment 112 are straight segments, and both are directly connected to both ends of the single-turn helical spring 113a. In one embodiment, the first meridional connecting segment 111 and the second meridional connecting segment 112 are arranged in parallel and are both parallel to the axial centerline of the support.

[0074] In this embodiment, in order to ensure that the latitudinal convex elastic segment 123 has excellent elastic deformation and recovery capabilities, the latitudinal convex elastic segment 123 also adopts a single-turn helical spring 123a (i.e., a single-turn spring structure), and its two ends are respectively connected to the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122.

[0075] In one embodiment, both the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122 include arc segments and curved segments; wherein, the arc segment of the first latitudinal connecting segment 121 is connected to one end of the single-turn helical spring 123a through its curved segment, and the arc segment of the second latitudinal connecting segment 122 is connected to the other end of the single-turn helical spring 123a through its curved segment; and the arc segments of the first latitudinal connecting segment 121 and the arc segments of the second latitudinal connecting segment 122 are located on the same circumference. In another embodiment, both the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122 are arc segments, located on different circumferences and arranged in parallel, and the two arc segments are directly connected to both ends of the single-turn helical spring 123a.

[0076] The warp-to-back convex elastic segment 113 and the weft-to-back convex elastic segment 123 are configured to utilize the geometric-mechanical coupling characteristics of a single-turn helical spring, where the coil diameter decreases during tension (reduction) and increases during compression (expansion). This allows the spring to exhibit low stiffness (first stiffness) within a small deformation range (normal breathing), enabling the corresponding displacement of each connecting segment and the tracheal wall. When the deformation exceeds a preset dead zone (such as cough impact), the change in spring coil diameter tends to saturate, and the geometric constraint causes the stiffness to jump to the second stiffness, thereby resisting further displacement and preventing the support from shifting. This solution can achieve the above-mentioned nonlinear stiffness response through the geometric parameters of the spring (coil diameter, wire diameter, pitch), without the need for additional sensing or driving elements.

[0077] Specifically, the geometric parameters of the longitudinal inward convex elastic segment 113 and the latitudinal inward convex elastic segment 123 are configured as follows: wire diameter 0.6-3mm, coil diameter 2-4mm in its natural state, and pitch 0.8-3.0mm; when the absolute value of the corresponding relative displacement in the longitudinal or latitudinal direction is less than the first threshold, the spring structure is in a free deformation state, exhibiting the first stiffness, and realizing the follow-up displacement of each connecting segment and the tracheal wall; when the absolute value of the relative displacement in the longitudinal or latitudinal direction exceeds the second threshold, the spring structure experiences contact or geometric constraint saturation, exhibiting the second stiffness greater than the first stiffness, to resist displacement under cough impact; in the transition zone between the first and second thresholds, the stiffness gradually changes nonlinearly.

[0078] In this embodiment, the axial relative displacement refers to the change in distance between the first and second meridional connecting segments in the meridional unit along the longitude direction (the direction of the long axis of the trachea) relative to the natural state. The latitudinal relative displacement refers to the change in distance between the first and second latitudinal connecting segments in the latitudinal unit structure along the latitudinal direction (the direction of the circumferential tangent of the trachea) relative to the natural state. Both are represented by positive values ​​indicating moving away from each other (stretching) and negative values ​​indicating moving closer to each other (compression). Their absolute values ​​are used to determine the deformation stage of the spring (free deformation zone, transition zone, or contact zone).

[0079] For a single-turn helical spring, its stiffness is not constant with increasing deformation. In the small deformation stage (e.g., the absolute value of the axial relative displacement is less than the first threshold), the spring coils maintain sufficient clearance, and the spring mainly undergoes elastic deformation, exhibiting a basically constant first stiffness (low stiffness). As the deformation increases and enters the transition zone (between the first and second thresholds), the geometry of the spring coils changes significantly. The clearance between the coils gradually decreases, and the spatial radius of curvature of the spring wire changes, causing the spring stiffness to begin to increase nonlinearly. When the deformation exceeds the second threshold, the spring coils come into contact (compression state) or the geometric constraint tends to saturate, and the spring stiffness rises sharply to the second stiffness (high stiffness). At this point, the spring exhibits a significant resistance to further deformation.

[0080] This technical solution utilizes the inherent nonlinear stiffness characteristics of a single-turn helical spring. By rationally designing the spring's initial geometric parameters (wire diameter, coil diameter, initial pitch, etc.), it matches the spring's three response ranges—"low stiffness - transition zone - high stiffness"—with the characteristic displacements of tracheal physiological deformation (small displacement during normal breathing, large displacement during coughing). This achieves adaptive mechanical behavior of "following the movement during normal breathing and anchoring during coughing." No additional sensors or driving elements are required; this can be achieved solely through the spring's own geometric-mechanical coupling characteristics.

[0081] Example 2

[0082] like Figures 3 to 5 As shown, this embodiment is largely the same as the 3D printed tracheal stent in Embodiment 1, except for the structure of the radially convex elastic segment 21 in the radial unit 11.

[0083] like Figure 5 As shown, the inwardly convex elastic segment 21 includes two single-turn helical springs 21a and a straight segment 21b (i.e., a double-turn spring structure); the first ends of the two single-turn helical springs 21a are respectively connected to the first meridional connecting segment 111 and the second meridional connecting segment 112, and the second ends of the two single-turn helical springs 21a are respectively connected to the two ends of the straight segment 21b.

[0084] This combination approach has the following characteristics: The latitudinal direction employs a single-coil spring structure, which is simple and can adapt to the uniform expansion and contraction of the trachea circumferentially, maintaining the overall compliance of the stent in cross-section; the meridional direction uses a double-coil spring structure with a straight section, providing greater axial deformation travel and a smoother stiffness transition, suitable for areas requiring greater axial tension or compression. Therefore, this combination is particularly suitable for stent design near the carina or at the junction of the main and branch trachea, where good circumferential apposition is required during breathing and coughing, along with strong axial deformation adaptability and anti-displacement capabilities. For patients with lesions at the carina location, stenosis in the middle and lower segments of the main trachea, or accompanied by tracheomalacia, this combination can effectively resist axial displacement while ensuring circumferential tightness, reducing the risk of stent displacement.

[0085] Example 3

[0086] like Figures 6 to 8 As shown, this embodiment is largely the same as the 3D printed tracheal stent in Embodiment 2, except for the structure of the latitudinal inward convex elastic segment 22 in the latitudinal unit 12.

[0087] like Figure 8 As shown, the latitudinal inward convex elastic segment 22 includes two single-turn helical springs 22a and a straight segment 22b (i.e., a double-turn spring structure); the first ends of the two single-turn helical springs 22a are respectively connected to the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122, and the second ends of the two single-turn helical springs 22a are respectively connected to the two ends of the straight segment 22b.

[0088] Compared to single-coil spring structures in both the longitudinal and latitudinal directions, this combination offers the following advantages: The double-coil spring structure connects two springs in series via a straight section in the middle. This disperses the deformation of the springs during axial tension or compression, resulting in a more uniform stress distribution, a larger total deformation stroke, and a smoother, more linear stiffness transition. Simultaneously, the straight section acts as a rigid connector, preventing direct collisions between coils during excessive spring compression and extending fatigue life. Therefore, this combination is particularly suitable for patients whose trachea needs to withstand large-scale, high-frequency deformations, such as those with severe tracheomalacia, chronic cough, or those requiring long-term intubation. For these patients, the dual-spring structure in both the longitudinal and latitudinal directions provides stable and compliant follow-up displacement during the respiratory cycle, effectively resisting stent fatigue and displacement caused by repeated deformation, while reducing local stress stimulation on the tracheal wall and lowering the risk of granulation tissue proliferation.

[0089] Example 4

[0090] like Figures 9 to 11 As shown, this embodiment is largely the same as the 3D printed tracheal stent in Embodiment 1, except for the structure of the meridional inward convex elastic segment 31 in the meridional unit 11 and the latitudinal inward convex elastic segment 32 in the latitudinal unit 12.

[0091] like Figure 11 As shown, the radially convex elastic segment 31 includes a three-quarter turn helical spring segment 31a, an arc segment 31b, a straight segment 31c, and a curved segment 31d (i.e., a three-quarter spring structure) connected in sequence; the first radial connecting segment 111 is connected to the starting end of the three-quarter turn helical spring segment 31a, and the second radial connecting segment 112 is connected to the end of the curved segment 31d away from the straight segment 31c; and the straight segment 31c and the arc segment 31b are located radially inside the first radial connecting segment 111.

[0092] like Figure 11 As shown, the latitudinal inward convex elastic segment 32 includes a three-quarter turn helical spring segment 32a, an arc segment 32b, a straight segment 32c, and a curved segment 32d (i.e., a three-quarter spring structure) connected in sequence; the first latitudinal connecting segment 121 is connected to the starting end of the three-quarter turn helical spring segment 32a, and the second latitudinal connecting segment 122 is connected to the end of the curved segment 32d away from the straight segment; and the straight segment 32c and the arc segment 32b are located inside the first latitudinal connecting segment 121 in the radial direction.

[0093] Both the meridional inward convex elastic segment 31 and the latitudinal inward convex elastic segment 32 adopt a three-quarter spring structure. In the meridional direction, the first meridional connecting segment 111 and the second meridional connecting segment 112 form a discontinuous spatial layout (including axially collinear / non-collinear interval arrangement), and there is no overlapping part or overlapping point or segment on the tracheal inner wall area corresponding to each of them. In the latitudinal direction, the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122 also have the same spatial arrangement, and there is no projection overlap between the tracheal inner wall areas corresponding to the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122. Compared with the conventional single-turn helical spring structure, the three-quarter spring structure can effectively avoid motion coupling caused by the projection overlap of the connecting segments, ensuring that when the trachea in one connecting segment area deforms, it will not directly drive the other connecting segment to move synchronously, thus achieving a more thorough mechanical decoupling. Therefore, this combination is particularly suitable for patients with short axial spacing between connecting segments or significant local tracheal deformation, such as stenosis near the carina, localized stenosis in the middle segment of the main trachea, or patients with local tracheal softening or collapse. For these patients, the three-quarter spring structure can provide precise follow-up displacement within a limited space, avoiding mutual interference between connecting segments, further reducing the risk of displacement, and reducing local stress concentration on the tracheal wall, which is beneficial for postoperative recovery and long-term stability. Short axial spacing between connecting segments refers to a small initial straight-line distance between the first and second meridional connecting segments along the long axis (longitudinal direction) of the trachea within the same meridional unit.

[0094] Example 5

[0095] like Figures 12 to 14 As shown, this embodiment is largely the same as the 3D printed tracheal stent in Embodiment 1, except for the structure of the meridional inward convex elastic segment 41 in the meridional unit 11 and the latitudinal inward convex elastic segment 42 in the latitudinal unit 12.

[0096] like Figure 14 As shown, the radially convex elastic segment 41 includes two three-quarter turn helical spring segments 41a, two arc segments 41b, and a straight segment 41c (i.e., a double three-quarter spring structure). The first ends of the two three-quarter turn helical spring segments 41a are respectively connected to the first radial connecting segment 111 and the second radial connecting segment 112. The second ends of the two three-quarter turn helical spring segments 41a are respectively connected to one end of the two arc segments 41b. The other ends of the two arc segments 41b are connected to each other through the straight segment 41c. The straight segment 41c and the arc segments 41b are located radially inside the first radial connecting segment 111.

[0097] like Figure 14 As shown, the latitudinal inward convex elastic segment 42 includes two three-quarter turn helical spring segments 42a, two arc segments 42b, and a straight segment 42c (i.e., a double three-quarter spring structure). The first ends of the two three-quarter turn helical spring segments 42a are respectively connected to the first latitudinal connecting segment 121 and the second latitudinal connecting segment 122. The second ends of the two three-quarter turn helical spring segments 42a are respectively connected to one end of the two arc segments 42b. The other ends of the two arc segments 42b are connected to each other through the straight segment 42c. The straight segment 42c and the arc segment 42b are located inside the first latitudinal connecting segment in the radial direction.

[0098] Compared to the conventional single-turn helical spring structure, the double three-quarters spring structure has the following advantages: First, the two three-quarters-turn helical spring segments are symmetrically arranged. The first and second meridional connecting segments 111 and 112 in the meridional direction, as well as the first and second latitudinal connecting segments 121 and 122 in the latitudinal direction, form a spatially discontinuous layout without projected overlap. This completely eliminates motion coupling caused by overlapping connecting segments, ensuring that when the trachea in the region of the first meridional connecting segment 111 deforms in the same meridional unit, it will not directly drive the second meridional connecting segment 112 to move synchronously. It also ensures that in the same latitudinal unit, when the trachea in the region of the first meridional connecting segment 111 deforms, it will not directly drive the second meridional connecting segment 112 to move synchronously. When the trachea in the first latitudinal connecting segment 121 deforms, it does not directly drive the second latitudinal connecting segment 122 to move synchronously, achieving more complete mechanical decoupling. Secondly, the series design of the dual springs and straight segments significantly increases the total axial deformation stroke, resulting in a more uniform stress distribution and a smoother stiffness transition. This allows the stent to withstand greater tensile and compressive displacements without inter-coil contact or plastic deformation. Furthermore, the symmetrical structure of the two spring segments makes the stent's follow-up response more balanced in the meridional and latitudinal directions, making it particularly suitable for complex physiological environments that require maintaining low stiffness compliance over a large displacement range while providing sufficient anchoring force under extreme deformation. Therefore, this combination is particularly suitable for patients whose trachea needs to withstand large-scale, multi-directional, and high-frequency deformation, such as patients with extensive tracheomalacia, chronic intractable cough, and repeated displacement after multiple stent placements, as well as cases where the carina region and proximal main bronchus require both high axial and circumferential compliance and anti-displacement capabilities. For these patients, the dual three-quarter spring structure can provide stable, compliant, and sustained follow-up displacement during the respiratory cycle, significantly reducing the risk of stent displacement and granulation tissue proliferation, and extending the effective service life of the stent.

[0099] Based on the above embodiments, the first meridional connecting segment, the second meridional connecting segment, the first latitudinal connecting segment, and the second latitudinal connecting segment are collectively referred to as "connecting segments." According to the patient's specific anatomical characteristics and mechanical requirements, each connecting segment can be independently selected from one or more combinations of the following configurations: a combination of straight and curved segments, a single continuous straight segment, or an arc segment with a large radius of curvature. That is, the specific configuration of the connecting segment can be adaptively selected and combined according to clinical needs to achieve a smooth transition with the spring segment and optimal fit with the tracheal wall. Those skilled in the art should understand that the structure of the meridional inwardly convex elastic segment and the latitudinal inwardly convex elastic segment is not limited to a fixed combination. According to the patient's specific anatomical characteristics, lesion type, and mechanical requirements, the "single-coil spring structure," "double-coil spring structure," "three-quarters spring structure," and "double three-quarters spring structure" used in the meridional unit can be freely combined with the "single-coil spring structure," "double-coil spring structure," "three-quarters spring structure," and "double three-quarters spring structure" used in the latitudinal unit. For example, for patients whose main trachea needs to withstand significant axial deformation while requiring good circumferential compliance in the carina region, a double-coil spring structure in the meridional direction and a single-coil spring structure in the latitudinal direction can be selected. Conversely, for patients requiring complete elimination of overlapping projections in the connecting segments, a three-quarters spring structure or a double three-quarters spring structure in both the meridional and latitudinal directions can be chosen. This modular structural selection allows for precise customization of the stent's mechanical properties, meeting personalized treatment needs in various clinical scenarios, from benign stenosis and tracheomalacia to complex carina lesions.

[0100] Furthermore, this invention also provides a method for preparing a 3D-printed tracheal stent, comprising the following steps:

[0101] Step S1: Obtain three-dimensional anatomical data of the patient's trachea.

[0102] CT or MRI images of the patient's trachea are collected, and a three-dimensional model of the trachea is reconstructed using image processing software. Geometric parameters such as the length of the stenotic segment, the inner diameter, and the bifurcation angle of the carina are measured, and the axial displacement and circumferential change rate of the trachea during the respiratory cycle are obtained.

[0103] Step S2: Based on the three-dimensional anatomical data, establish a three-dimensional model of the columnar mesh support composed of the meridional units and the latitudinal units, and determine the structural parameters of each unit structure.

[0104] In 3D modeling software (such as CAD, SolidWorks, Rhino, or specialized medical modeling software), design the stent model based on the anatomical parameters obtained in step S1. Determine the number and arrangement of the meridional and latitudinal units, as well as the structural form of each unit (single-coil spring structure, double-coil spring structure, three-quarter spring structure, and double three-quarter spring structure). Set the geometric parameters of the spring structure, such as wire diameter, coil diameter, pitch, and length of each connecting segment, so that the stent exhibits low stiffness compliance during normal breathing and high stiffness anchoring force during coughing. After completing the modeling, export the STL format file.

[0105] Step S3: Import the three-dimensional model into the 3D printing system.

[0106] Import the STL model into the slicing software and set the FDM printing parameters: nozzle diameter 0.3–0.4 mm, layer height 0.15–0.2 mm, printing speed 10–50 mm / s (use the lower value for the spring section). Set the extrusion temperature and platform temperature according to the selected biodegradable polymer material, generate the printing path code, and then transfer it to the four-axis FDM printer.

[0107] Step S4: Using biodegradable polymer materials, a tracheal stent is obtained by integral molding through fused deposition modeling 3D printing technology.

[0108] The 3D-printed tracheal stent is integrally formed using biodegradable polymer fused deposition modeling (FDM). Key printing parameters are set as follows: nozzle temperature 110–140℃ (adjustable depending on the blending ratio), platform temperature 30–40℃, layer height 0.15–0.2 mm, spring section printing speed 10–20 mm / s (connecting section 30–50 mm / s), and nozzle diameter 0.3–0.4 mm. A four-axis linkage mode is used during printing, with A-axis rotation combined with X / Y / Z-axis movement to stack layers sequentially, ensuring simultaneous formation of warp and weft units. The dried biodegradable polymer filament is loaded into the printer, and printing is initiated. Warp and weft units are stacked layer by layer using A-axis rotation combined with X / Y / Z-axis movement, resulting in an integral structural unit. After printing, the support is removed, the unit is cleaned and dried, and sterilized and packaged after passing dimensional and biocompatibility tests.

[0109] The biodegradable polymer is selected from one or more of polycaprolactone (PCL), polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA), and poly(L-lactide-co-ε-caprolactone) (PLCL). Specifically, in this embodiment, the biodegradable polymer is selected from polycaprolactone (PCL) filaments.

[0110] To further verify the technical effectiveness of the above structural design, a tracheal stent (single-loop spring structure) was fabricated using the above method. The biodegradable polymer used was polycaprolactone (PCL) filament. The tracheal stent includes six warp chains and multiple weft units 12 connected between the warp chains, such as... Figure 15 As shown. The parameters of the tracheal stent are as follows:

[0111] Wire diameter: 1mm in the warp direction, 1.2mm in the weft direction; warp inward convex elastic section diameter: 2.8mm; warp inward convex elastic section pitch: 1.6mm; first warp connecting section length: 2.5mm; second warp connecting section length: 2.5mm; weft inward convex elastic section diameter: 3.0mm; weft inward convex elastic section pitch: 1.6mm; first weft connecting section length: 7.5mm; second weft connecting section length: 7.5mm; tracheal stent diameter in natural state: 26mm.

[0112] This invention simulates the axial tensile mechanical behavior of the support using finite element analysis software (such as Abaqus). The boundary conditions of the simulation model are set as follows: the bottom of the support is fixed, and a tensile displacement of 20 mm is applied axially at the top. The material parameters are set based on the measured mechanical properties of polycaprolactone (PCL). The stress cloud diagram extracted from the simulation is shown below. Figure 16 As shown, the force-displacement curve is as follows: Figure 17 As shown.

[0113] like Figure 16 As shown, the connecting sections (including the first and second meridional connecting sections) are dark blue (stress values ​​approximately 0–5 MPa), indicating that the connecting sections bear almost no stress during axial tension. The bending areas of the single-turn helical spring sections are red (stress values ​​approximately 15–23.386 MPa), with the maximum stress of 23.386 MPa occurring at the bend. The transition area between the single-turn helical spring section and the connecting sections is green to yellow (stress values ​​approximately 5–15 MPa), showing a smooth stress transition. Looking at the color bars on the left side of the stress cloud diagram, the color range corresponding to the values ​​of 11.693–13.642 MPa in the middle section covers most of the support structure. This range represents the main stress level of the support structure after axial tension of 20 mm. This stress value is far lower than the yield strength of polycaprolactone (PCL) filament (tested to be 20–30 MPa for pure PCL filament), indicating that the support structure is in the elastic deformation range, and the structure is unlikely to undergo plastic deformation or failure under this condition. The stress distribution characteristics described above indicate that the single-turn helical spring segment, as an independent deformation absorption unit, bears the main deformation load, while the connecting segment always maintains a low stress state, can adhere to the inner wall of the trachea and move synchronously with it, thus verifying the design principle of "mechanical decoupling between the connecting segment and the single-turn helical spring segment" of this invention.

[0114] like Figure 17 As shown, the loading curve exhibits a nonlinear response characteristic of softening followed by hardening. In the initial loading stage, the slope of the curve gradually decreases with increasing displacement, indicating a decrease in stiffness (softening). This stage corresponds to the structural compliance of a single-turn helical spring in the early stage of deformation—the coil diameter of the single-turn helical spring shrinks under axial tension, and the internal stress of the material redistributes, allowing the tracheal stent to adapt to the small deformation of the trachea with low resistance, achieving the follow-up displacement of the connection section and the tracheal wall. This is the first stiffness stage, corresponding to the mechanical requirements during normal breathing. As the displacement continues to increase, the slope of the curve gradually increases, and the stiffness begins to recover and continues to strengthen, indicating that the spring segment has entered the nonlinear hardening region. The spring coil gap decreases, and the geometric constraint tends to saturate. This is the second stiffness stage, where the tracheal stent resists further stretching with higher resistance, corresponding to high impact load scenarios such as coughing, effectively preventing the stent from being overstretched and displaced. This "softening then hardening" mechanical behavior is consistent with the mechanical response characteristics of natural gas pipes under physiological loads, which are "compliant and flexible during small deformations and resistant to excessive stretching during large deformations," achieving a biomimetic match with the biomechanical properties of natural gas pipes.

[0115] The unloading curves show that as the displacement decreases from its maximum, the load gradually decreases, indicating that the spring segment gradually recovers its deformation. Furthermore, the force value on the unloading curve is lower than that on the loading curve (e.g., at a displacement of approximately 5 mm, the loading curve force is approximately 1.5 N, while the unloading curve force is approximately 1.1-1.2 N), indicating that the spring segment dissipates some energy through material viscoelasticity during deformation, which helps absorb the energy of impact loads such as coughing and reduces the impact transmission to the tracheal wall. However, when the displacement decreases to a certain value, the load decreases in a reversed trend, slowly increasing as the displacement continues to decrease. When the displacement finally reaches zero, the load does not completely return to zero, indicating a certain residual load. This phenomenon reflects the viscoelastic hysteresis and partial non-fully recoverable molecular chain slippage of the PCL under large deformation. A moderate residual load helps the tracheal stent to quickly return to its original position after tracheal deformation, and the stress value corresponding to the residual load is far lower than the yield strength of the PCL, preventing continuous excessive pressure on the tracheal wall.

[0116] This invention also simulated the lateral compressive mechanical behavior of the support using finite element analysis software (such as Abaqus). The boundary conditions of the simulation model were set as follows: one side of the support was fixed, and a compressive displacement of 15 mm was applied to the other side. The material parameters were set based on the measured mechanical properties of polycaprolactone (PCL). The stress cloud diagram extracted from the simulation is shown below. Figure 18 As shown, the force-displacement curve is as follows: Figure 19 As shown.

[0117] like Figure 18As shown, the overall stress level of the tracheal stent is relatively low, with a maximum stress value of approximately 10.772 MPa, occurring at the bending point of the spring segment in the lateral compression area of ​​the tracheal stent. The latitudinal connecting segments (including the first and second latitudinal connecting segments) exhibit extremely low stress (dark blue to light blue area, stress value approximately 0–3.5 MPa), indicating that the connecting segments bear almost no stress during lateral compression. The stress in the transition area between the spring segment and the connecting segment shows a smooth transition (green to yellow area, stress value approximately 3.5–8 MPa). These stress distribution characteristics indicate that under lateral compression loads, the spring segment still acts as the main deformation-absorbing unit, absorbing compression displacement through changes in coil diameter, while the connecting segment maintains a low stress state throughout. This verifies the applicability of the design principle of "mechanical decoupling between the connecting segment and the spring segment" in this invention under radial loads.

[0118] like Figure 19 As shown, the loading curve exhibits a non-linear upward trend, with the slope gradually decreasing as displacement increases. Initially, the load increases rapidly with displacement, resulting in relatively high stiffness. As the compression displacement continues to increase, the curve flattens, and the load growth rate gradually decreases. This indicates that the spring segment undergoes a change in geometric configuration during lateral compression, with the spring coil gradually flattened. The structural stiffness (the slope of the tangent to the curve) gradually decreases with increasing deformation. This "stiffness reduction" softening characteristic suggests that within this compression displacement range, the spring is primarily in the elastic deformation stage and has not yet entered the geometric constraint saturation region. The decrease in stiffness in the later stages of compression slows the increase in resistance when the stent is subjected to large radial deformation, preventing excessive radial pressure on the tracheal wall. The unloading curve largely coincides with the loading curve, with no obvious hysteresis loop or residual load, indicating that the stent did not experience significant viscoelastic hysteresis or plastic deformation during lateral compression and possesses good elastic recovery capability.

[0119] Further comparison of lateral compression simulation results with axial tension simulation results reveals that the loading curve under axial tension exhibits a nonlinear characteristic of "softening initially and then hardening," while the loading curve under lateral compression exhibits a nonlinear characteristic of "gradual softening" (decreasing stiffness). The maximum stress under axial tension is approximately 23.386 MPa, while the maximum stress under lateral compression is approximately 10.772 MPa, with the lateral compression stress level being approximately 46% of that under axial tension. These differences indicate that the stent provides high-stiffness deformation absorption in the axial direction through the spring segment to resist displacement under high impact loads such as coughing; while in the radial direction, it achieves low-stiffness compressive compliance through the latitudinal unit structure, ensuring that the stent can follow the radial expansion and contraction of the trachea and avoid excessive radial pressure on the tracheal wall. This anisotropic mechanical response characteristic is highly compatible with the physiological and mechanical requirements of the trachea—the trachea needs to resist the anchoring force of displacement in the axial direction and needs to be compliant with respiratory movements in the radial direction.

[0120] In summary, the lateral compression simulation results and the axial tension simulation results complement each other, jointly verifying the core mechanical design of this invention: the spring segment independently bears deformation loads in different directions through changes in coil diameter, the connecting segment always maintains a low stress state, and there is no relative sliding between it and the tracheal wall, fundamentally eliminating the mechanical root cause of stent displacement. The stent's good elastic recovery ability and suitable radial compliance under lateral compression further corroborate that the stent described in this invention can conform to the radial deformation of the trachea in clinical applications, making it suitable for patients with large local tracheal deformation.

[0121] It is worth noting that the human trachea undergoes complex deformation with multiple degrees of freedom during normal physiological activities. Studies have shown that the axial displacement of the trachea during quiet breathing is approximately 1–2 mm, while the axial displacement can reach 3–5 mm during coughing, with a tracheal circumference change rate of approximately 5%–15%. Taking the adult tracheal transverse diameter as approximately 20–25 mm, the radial displacement corresponding to the circumference change is approximately 1–3.75 mm. These physiological parameters constitute the basic load spectrum for the mechanical design of tracheal stents.

[0122] The simulation conditions of this invention are set as axial tension of 20 mm and lateral compression of 15 mm, which are equivalent to 10-20 times the normal respiratory displacement, 4-6.7 times the cough displacement, and 4-15 times the physiological radial displacement, respectively. Under such extreme loading conditions, the overall stress level of the stent remains within the elastic range of the PCL material, and the structure does not fail, verifying that the stent has sufficient mechanical safety margin and functional reliability. This result shows that the mechanical properties of the stent described in this invention fully cover the deformation requirements of the human trachea under physiological conditions such as normal breathing, deep breathing, and violent coughing, effectively avoiding structural failure or displacement caused by physiological loads, and meeting the mechanical requirements for clinical applications.

[0123] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure, and they should all be covered within the scope of the claims and specification of this disclosure.

Claims

1. A 3D-printed tracheal stent, characterized in that, include: Multiple warp units, each of the warp units including a first warp connecting segment, a second warp connecting segment, and a warp inward convex elastic segment connecting the first warp connecting segment and the second warp connecting segment; as well as Multiple latitudinal units, each latitudinal unit including a first latitudinal connecting segment, a second latitudinal connecting segment, and a latitudinal inwardly convex elastic segment connecting the first latitudinal connecting segment and the second latitudinal connecting segment; Among them, multiple meridional units are connected in series along different longitude directions to form multiple meridional chains, and the multiple meridional chains are arranged at intervals in the circumferential direction; multiple latitudinal units are respectively connected between two adjacent meridional chains, and the multiple meridional chains and multiple latitudinal units are interconnected to form a columnar grid support. Both the meridional inward convex elastic segment and the latitudinal inward convex elastic segment protrude radially inward toward the columnar grid support, and are independently configured such that when the trachea deforms, through their own elastic deformation, they respectively drive the corresponding first meridional connecting segment, second meridional connecting segment, first latitudinal connecting segment and second latitudinal connecting segment to move synchronously with the inner wall of the trachea, so as to avoid relative sliding between each connecting segment and the inner wall of the trachea.

2. The 3D-printed airway support according to claim 1, characterized in that: The radially convex elastic segment is a single-turn helical spring, with its two ends connected to the first radial connecting segment and the second radial connecting segment, respectively.

3. The 3D-printed airway support according to claim 1, characterized in that: The radially convex elastic segment includes two single-turn helical springs and a straight segment; the first ends of the two single-turn helical springs are respectively connected to the first radial connecting segment and the second radial connecting segment, and the second ends of the two single-turn helical springs are respectively connected to the two ends of the straight segment.

4. The 3D-printed tracheal stent according to claim 1, characterized in that: The radially convex elastic segment includes a three-quarter turn helical spring segment, an arc segment, a straight segment, and a curved segment connected in sequence; the first radial connecting segment is connected to the starting end of the three-quarter turn helical spring segment, and the second radial connecting segment is connected to the end of the curved segment away from the straight segment; and the straight segment and the arc segment are located radially inside the first radial connecting segment.

5. The 3D-printed airway support according to claim 1, characterized in that: The radially convex elastic segment includes two three-quarter turn helical spring segments, two arc segments, and one straight segment; the first ends of the two three-quarter turn helical spring segments are respectively connected to the first radial connecting segment and the second radial connecting segment, the second ends of the two three-quarter turn helical spring segments are respectively connected to one end of the two arc segments, the other ends of the two arc segments are connected to each other through the straight segment, and the straight segment and the arc segment are located radially inside the first radial connecting segment.

6. The 3D-printed tracheal stent according to claim 1, characterized in that: The convex elastic segment in the weft direction is a single-turn helical spring, with its two ends connected to the first weft connecting segment and the second weft connecting segment, respectively.

7. The 3D-printed airway support according to claim 1, characterized in that: The latitudinal inward convex elastic segment includes two single-turn helical springs and a straight segment; the first ends of the two single-turn helical springs are respectively connected to the first latitudinal connecting segment and the second latitudinal connecting segment, and the second ends of the two single-turn helical springs are respectively connected to the two ends of the straight segment.

8. The 3D-printed tracheal stent according to claim 1, characterized in that: The latitudinal inward convex elastic segment includes a three-quarter turn helical spring segment, an arc segment, a straight segment, and a curved segment connected in sequence; the first latitudinal connecting segment is connected to the starting end of the three-quarter turn helical spring segment, and the second latitudinal connecting segment is connected to the end of the curved segment away from the straight segment; and the straight segment and the arc segment are located radially inside the first latitudinal connecting segment.

9. The 3D-printed airway support according to claim 1, characterized in that: The latitudinal inward convex elastic segment includes two three-quarter turn helical spring segments, two arc segments, and one straight segment; the first ends of the two three-quarter turn helical spring segments are respectively connected to the first latitudinal connecting segment and the second latitudinal connecting segment, the second ends of the two three-quarter turn helical spring segments are respectively connected to one end of the two arc segments, the other ends of the two arc segments are connected to each other through the straight segment, and the straight segment and the arc segment are located radially inside the first latitudinal connecting segment.

10. A method for preparing a 3D-printed tracheal stent as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step S1: Obtain three-dimensional anatomical data of the patient's trachea; Step S2: Based on the three-dimensional anatomical data, establish a three-dimensional model of the columnar mesh support composed of the meridional units and the latitudinal units, and determine the structural parameters of each unit structure; Step S3: Import the three-dimensional model into the 3D printing system; Step S4: Using biodegradable polymer materials, a tracheal stent is obtained by integral molding through fused deposition modeling 3D printing technology.

Images