Implants and methods for forming implants

Abstract

The present embodiment relates to a three-dimensional implant for tissue reconstruction or augmentation, for insertion into a patient. The implant includes a plurality of strands forming a three-dimensional structure with a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. The sidewalls include a plurality of strand segments and a plurality of gaps, alternating such that a gap is formed between adjacent strand segments. The plurality of gaps are reversibly expandable gaps. The adjacent strand segments define a deflection capacity (δ) based on an object received in the reversibly expandable gap. The radius (R) of the strand segments and the gap length (gl) of the reversibly expandable gap determine a yield strength (σ). yield ), the elastic modulus of the material (E), and the deflection capacity δ of adjacent strand segments.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to European Patent Application No. 20186961.7, filed with the European Patent Office on July 21, 2020, the entire contents of which are incorporated herein for all purposes.

[0002] FIELD OF THE INVENTION The embodiments described herein relate to the field of implants, and more particularly to implants for insertion into a patient and methods for forming the implants. [Background technology]

[0003] Surgeries to insert implants into patients are performed worldwide. Depending on the required use of the implant, the implant may be required to meet certain criteria. Such criteria may relate to the shape of the implant and / or the mechanical stability of the implant. In some cases, such as when an implant is used in reconstructive surgery, the surgeon may need to handle the implant before, during, and / or after it is inserted into the patient. It is desirable for the implant to meet the geometric and mechanical criteria required by the patient and to be easily handled and / or manipulated by the surgeon performing the implant procedure. Summary of the Invention

[0004] Various embodiments are directed to providing an implant that can be flexibly tailored to meet the criteria required for the reconstruction of a patient's body part, while also enhancing and improving the handling and maneuverability of the implant by the operating surgeon.

[0005] Embodiments described herein relate to a three-dimensional implant for insertion into a patient. The implant includes a plurality of strands forming a three-dimensional structure. The three-dimensional structure includes a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. The sidewalls include a plurality of strand segments and a plurality of gaps, alternating such that a gap is formed between adjacent strand segments in the sidewall. The gaps are comprised of a gap length (gl) and a resting gap height (gh). The plurality of gaps are reversibly expandable gaps. The gap height increases with an object received by the gap, and the gap height decreases with the object removed from the gap. The plurality of strands have a yield strength (σ yield The radius (R) of the strands and the gap length (gl) of the reversibly expandable gap are determined by the yield strength (σ yield ), the elastic modulus of the material (E), and the deflection capacity δ of adjacent strand segments to form a reversibly expandable gap.

[0006] Various embodiments relate to an implant for use in guiding a needle through the implant for an implant procedure.

[0007] Various embodiments relate to a method for forming a three-dimensional implant. The method includes forming a plurality of strands to form a three-dimensional structure. The plurality of strands has a yield strength (σ yield) and a modulus of elasticity (E). The three-dimensional structure includes a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls, each of which includes a plurality of gaps and a plurality of consecutive strand segments of a plurality of strands. The strand segments and the gaps are alternately arranged such that a gap is formed between adjacent strand segments in the sidewall. The gaps are comprised of a gap length (gl) and a static gap height (gh). The plurality of gaps are reversibly expandable gaps. The height of the reversibly expandable gap increases with an object received in the gap, and the height of the gap decreases with the object removed from the gap. The radius (R) of the plurality of strands and the gap length (gl) of the reversibly expandable gap are related to the yield strength (σ yield ), the elastic modulus of the material (E), and the deflection capacity δ of adjacent strand segments to form a reversibly expandable gap.

[0008] Various embodiments relate to a three-dimensional implant for tissue reconstruction or augmentation, intended for insertion into a patient. The implant includes a plurality of planar layers. A first set of sublayers includes a plurality of strands oriented in a first direction. A second set of sublayers includes a plurality of strands oriented in a second direction. The sublayers of the first set of sublayers and the sublayers of the second set of sublayers are alternately arranged in a third direction. The layers form a three-dimensional structure including a plurality of hollow channels extending in the third direction, and the implant is compressible along at least the third direction. Each hollow channel includes a first sidewall extending in the third direction and consisting of alternating strand segments oriented in the first direction and gaps, and a second sidewall extending in the third direction and consisting of alternating strand segments oriented in the second direction and gaps. At least one of the first and second sidewalls of the hollow channel is contoured. The strand segments of the contoured sidewall belong to different layers of the implant, adjacent strand segments of the contoured sidewall are separated by gaps, and adjacent strand segments have a lateral offset relative to one another to create a pattern of peaks and troughs in the contoured sidewall.

[0009] Finally, the present invention also relates to a method of tissue reconstruction or augmentation, which method comprises implanting an implant as defined herein into the body of a subject.

[0010] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. It is understood that the accompanying drawings illustrate only some embodiments in accordance with the present disclosure and are therefore not to be considered limiting of its scope. The present disclosure will be described with additional specificity and detail through the use of the accompanying drawings in order that the advantages of the present disclosure may be more readily grasped. [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 1A shows a perspective view of a three-dimensional implant 100 for insertion into a patient. [Figure 1B] FIG. 1B shows a side cross-sectional view of a three-dimensional implant 100 for insertion into a patient. [Figure 1C] FIG. 1C shows a gap in the implant between two adjacent strand segments in the sidewall. [Figure 1D] FIG. 1D shows the first sublayer of the implant. [Figure 1E] FIG. 1E shows the second sublayer of the implant. [Figure 1F] FIG. 1F shows a beam with two simple supports undergoing deflection. [Figure 1G] FIG. 1G illustrates the deflection of adjacent strand segments upon needle insertion. [Figure 1H] FIG. 1H shows the arrangement of adjacent strand segments when the lateral offset is zero. [Figure 1I] FIG. 1I shows the arrangement of adjacent strand segments when the lateral offset is greater than zero. [Figure 2A] FIG. 2A shows a perspective view of a further implant for insertion into a patient. [Figure 2B] FIG. 2B shows a cross-sectional side view of a further implant for insertion into a patient. [Figure 3A] FIG. 3A shows a perspective view of an implant suitable for use as a breast implant. [Figure 3B] FIG. 3B shows a perspective side view of an implant including multiple contouring strands and surface filler strands. [Figure 3C] FIG. 3C shows a perspective top view of an implant including multiple contouring strands and surface filler strands. [Figure 3D] FIG. 3D shows a perspective view of the implant. [Figure 4A] FIG. 4A shows a reversibly expandable gapless implant. [Figure 4B] FIG. 4B shows an image of inserting a cannula for fat injection into an implant having a reversibly expandable gap. [Figure 4C] Figure 4C shows an example of an insertable region for a multi-injection study. [Figure 4D] FIG. 4D shows the stress-strain curves of strands of different materials. [Figure 5A] FIG. 5A shows the implant after a fat injection sham surgery. [Figure 5B] FIG. 5B shows an image of the implant after fat injection. [Figure 5C] FIG. 5C shows an image of the implant after fat injection. [Figure 5D] FIG. 5D shows an image of the implant after fat injection. [Figure 6] FIG. 6 shows a flow chart of a method 600 for forming an implant. [Figure 7A] FIG. 7A shows an implant having at least one contoured sidewall. [Figure 7B] FIG. 7B shows an implant having at least one contoured sidewall. [Figure 7C] FIG. 7C shows an implant having at least one contoured sidewall. [Figure 7D] FIG. 7D shows an implant having at least one contoured sidewall. [Figure 7E]FIG. 7E shows an implant having at least one contoured sidewall. [Figure 7F] FIG. 7F shows an implant having at least one contoured sidewall. [Figure 7G] FIG. 7G shows an implant having at least one contoured sidewall. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the following detailed description, reference is made to the accompanying drawings, which show, by way of illustration, specific embodiments in which the claimed subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the subject matter. It is to be understood that various embodiments, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented in other embodiments without departing from the spirit and scope of the claimed subject matter. References herein to "one embodiment" or "an embodiment" mean that the particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment encompassed within the specification. Thus, use of the phrases "one embodiment" or "in an embodiment" does not necessarily refer to the same embodiment. Furthermore, it will be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the claimed subject matter. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the subject matter is defined solely by the appended claims, appropriately interpreted, along with the full range of equivalents to which such claims are entitled. In the drawings, like numerals indicate identical or similar elements or features throughout the multiple views, and indicate that the elements depicted therein are not necessarily to scale relative to each other, rather individual elements may be enlarged or reduced for easier understanding in the context of this specification.

[0013] As used herein, the terms "over," "to," "between," and "on" may refer to the relative position of a layer with respect to another layer. When a layer is "over" or "on" another layer, it may be in direct contact with the other layer or there may be one or more intervening layers. A layer that is "between" layers may be in direct contact with the layer or there may be one or more intervening layers. As used herein, the phrase "A, B, and / or C" may mean "A," "B," "C," "A and B," "B and C," "A and C," and "A and B and C."

[0014] 1A and 1B show a perspective view and a side cross-sectional view, respectively, of an implant 100 for insertion into a patient.

[0015] As shown in FIG. 1A, implant 100 includes a plurality of strands 101 that form a three-dimensional structure 102. Three-dimensional structure 102 includes a plurality of hollow channels 103. Each hollow channel 103 includes a plurality of sidewalls 104. Sidewalls 104 include a plurality of strand segments 105 and a plurality of gaps 106 (shown in FIG. 1B) that are alternately arranged such that gaps 106 are formed between adjacent strand segments 105 in sidewalls 104. Gaps 106 are reversibly expandable.

[0016] In general, a hollow channel 103 may be formed by at least three sidewalls that are contiguous with one another (or, for example, intersect with one another) such that the hollow space is enclosed by the sidewalls. In the example of Figure 1A, multiple hollow channels 103 are shown, each having a square cross-section. One (or each) hollow channel 103 with a square cross-section may have four intersecting sidewalls 104.

[0017] FIG. 1B shows a cross-sectional side view of the implant 100 along line A-A'. The side view shows multiple strands (also called filaments) 101 of a three-dimensional structure 102, with the multiple (parallel) strands 101 forming sidewalls 104, 104A of two adjacent (e.g., directly adjacent) channels 103, 103A in the three-dimensional structure 102. As shown in FIG. 1B, taking hollow channel 103A as an example, hollow channel 103A may include a first sidewall 104A (shown as a sidewall parallel to the page) formed from multiple parallel strands 101. Hollow channel 103A may further include a second sidewall 104B (shown as strands entering and / or exiting the page), a third sidewall 104C (shown as strands entering and / or exiting the page), and a fourth sidewall (not shown). The third sidewall 104C may be the sidewall opposite the second sidewall 104B. Both the second sidewall 104B and the third sidewall 104C may be continuous with the first sidewall 104A and the fourth sidewall. The fourth sidewall may be the sidewall opposite the first sidewall 104A. Where the sidewalls intersect, their strands may alternate.

[0018] One (or each) sidewall 104 of a channel 103, such as the sidewall 104A of the hollow channel 103A, may include multiple continuous strand segments 105A arranged consecutively in the z-direction (vertically). Each strand segment 105A may be part (or segment) of a longer continuous strand 101 that forms part of another sidewall 104 or the channel 103. If desired, the multiple continuous strand segments 105A forming the sidewall 104A of the hollow channel 103A may be substantially parallel to one another. Each sidewall 104A may further include multiple gaps 106A. The multiple gaps 106A and multiple strand segments 105A of the hollow channel 103A may be arranged alternately such that a gap 106A (e.g., one) may be located between adjacent (e.g., directly adjacent) strand segments 105A of the sidewall 104A (e.g., between two consecutive strand segments 105A of the sidewall 104A). Adjacent (eg, immediately adjacent or, eg, contiguous) strand segments may be separated by gaps 106A.

[0019] FIG. 1C shows a gap 106A between two adjacent strand segments 105A in a (single) sidewall 104A of a hollow channel 103A of implant 100.

[0020] The gap 106A, sometimes referred to as a slit and / or a spacing, refers to a blank space between the lengths of two adjacent strand segments 105A. The gap 106A may be defined by two pairs of intersecting strands 101 that form the periphery of the gap 106A (e.g., define or enclose the gap 106A). The first pair of strand segments 105A (parallel to the y-direction) of the first sidewall 104A may be opposing strands and / or may be substantially parallel to each other, as desired. The second pair of strand segments 105B, 105C may be opposing strands of the second and third sidewalls 104B, 104C and may be substantially parallel to each other. The gap 106A may be an area surrounded by the two pairs of intersecting strands. The first pair of strand segments 105A forming the gap 106A may be adjacent strand segments 105A in the same (first) sidewall 104A of the hollow channel 103A, and the second pair of strand segments may be opposing strands in the second sidewall 104B and the third sidewall 104C.

[0021] The gap 106A may have or be defined by a baseline gap height gh. The baseline (or resting) gap height gh may be the minimum (or smallest) height between two adjacent strands 105A when the implant 100 is at rest. Additionally or alternatively, the baseline gap height gh may be the height of the gap 106A at a midpoint region of the gap 106A (e.g., the midpoint region of the strand segments 105A of the gap 106A). Additionally or alternatively, the baseline gap height may be the average (mean) gap height of 80% or more of the gaps of the implant when the implant is at rest. Furthermore, the gap 106A may have or be defined by a baseline gap length gl, which is the maximal or largest dimension of the gap 106A. Additionally, the baseline gap length g may be the length of the strand segment between the second pair of strands 105B, 105C, such as between the two nearest edges of the first strand 105B and the second strand 105C (FIG. 1C), or alternatively, from the center of the first strand 105B to the center of the second strand 105C (FIG. 1G). The second pair of strands may be fused to the strand segments of the first pair where the two pairs intersect, and the second pair of strands may form simple supports for the strand segments of the first pair at both ends of the gap length g.

[0022] The two pairs of intersecting strands 101 may be fused or joined at the intersection region. Additionally, or optionally, the opposing strand segments 105A may have some slack or droop such that the baseline gap height gh is equal to or less than the average strand diameter d. As the gap height is expanded, the shape of the gap 106 may be changed or modified (e.g., by inserting a needle into the gap). Optionally, the area enclosed by the two pairs of intersecting strand segments 105A, 105B, and 105C may remain unchanged. Alternatively, or optionally, the area enclosed by the two pairs of intersecting strands 101 may increase to 110% or more (e.g., 120% or more, e.g., 150% or more, e.g., 200% or more, e.g., 120%-250%, e.g., 120%-200%) of the area originally enclosed.

[0023] FIG. 1C also illustrates the spring-like characteristics of the reversibly expandable gap 106 (e.g., gap 106A). When a tensile force (indicated by opposing arrows 113, 114) is applied to opposing strand segments 105A of gap 106A, the gap height gh increases. Additionally, opposing strand segments 105A of gap 106A may each be subjected to opposing tensile forces. When a tensile force is applied to the strand segments 105A of gap 106A, gap 106A may be configured to be expandable relative to a baseline gap height gh. For example, the reversibly expandable gap 106 may be expandable to 110% or more (or, e.g., 120% or more, or, e.g., 150% or more, or, e.g., 200% or more, or, e.g., between 110% and 250%, or, e.g., between 120% and 250%, or, e.g., between 120% and 200%) of the baseline gap height gh and / or average strand diameter d. The reversibly expandable gap 106A can recover or return to its original (resting) gap height after the tensile force (113, 114) is removed from the strands 105A in the gap 106A (even at the same ambient pressure and temperature). For example, the reversibly expandable gap 106A may be configured to recover or return to less than 110% (or, e.g., less than 105%, or, e.g., 100%, or, e.g., 80%-115%, or, e.g., 90%-110%) of its original gap height g and / or average strand diameter d after the tensile force acting on the strands 105A is removed.

[0024] Optionally, the baseline gap length gl may be two or more times (or, e.g., five or more times, or, e.g., ten or more times) the baseline gap height gh. Optionally, the baseline gap height gh may be between 0.05 mm and 5 mm (or, e.g., between 0.1 mm and 2 mm, or, e.g., between 0.5 mm and 1.5 mm). Optionally, the average thickness of the plurality of strands 101 may be between 0.05 mm and 5 mm (or, e.g., between 0.1 mm and 2 mm, or, e.g., between 0.5 mm and 1.5 mm). Optionally, the baseline gap length gl may be two or more times (or, e.g., five or more times, or, e.g., ten or more times) greater than the diameter d (or thickness) of the strand 101. For example, the baseline gap length gl may be less than 25 mm (or, e.g., between 0.5 mm and 25 mm). Optionally, the baseline gap height gh may be 40% to 100% (or, for example, 40% to 80%, or, for example, 40% to 60%) of the average (mean) strand diameter d of the strands 101 of the implant. While FIG. 1C shows only one strand segment 105B, 105C for each of the second sidewall 104B and the third sidewall 104C, it can be understood that multiple strands for each of the second sidewall 104B and the third sidewall 104C may be disposed between the first pair of strand segments 105A of the first sidewall 104A. In this case, the baseline gap height gh may depend on the total thickness of the second pair of strands in the z-direction. For example, the baseline gap height gh may be 40% to 100% (or, for example, 40% to 80%, or, for example, 40% to 60%) of the total thickness of the second pair of strands in the z-direction.

[0025] As shown in FIG. 1B , each hollow channel 103, 103A may include at least a first sidewall 104A including a first plurality of continuous strand segments 105A and a first plurality of reversibly expandable gaps 106. The hollow channel 103A may further include a second sidewall 104B including a second plurality of continuous strand segments and a second plurality of reversibly expandable gaps. The second sidewall 104B may be continuous with the first sidewall 104A. The strand segments 105A of the first plurality of continuous strand segments 105A and the strand segments 105B of the second plurality of continuous strand segments 105B may be alternately arranged in a direction between a first end 137 of the longitudinal axis of the hollow channel 103A and a second end 138 of the longitudinal axis of the hollow channel 103A.

[0026] The two sidewalls 104, 104A of adjacent channels 103, 103A may be separated (or divided) by a further sidewall 104B. The further sidewall 104B may comprise multiple strands (shown in FIG. 1B as entering the page). The strands of the further sidewall 104B may intersect with the strands 101 forming the sidewalls 104A, 104A. The channels of the multiple hollow channels 103 may be arranged adjacent to each other (e.g., directly adjacent). The adjacent channels 103A, 103B may share a common sidewall 104B.

[0027] The implant 100 may have different sizes depending on the purpose of the implant. In the x-direction, the implant may have a dimension of up to 30 cm (or, for example, between 1 cm and 30 cm, or, for example, between 10 cm and 15 cm). In the y-direction, the implant may have a dimension of up to 30 cm (or, for example, between 1 cm and 30 cm, or, for example, between 10 cm and 15 cm). In the z-direction, the implant may have a dimension of up to 30 cm (or, for example, between 1 cm and 30 cm, or, for example, between 10 cm and 15 cm).

[0028] The multiple strands 101 of the three-dimensional structure 102 of the implant 100 may constitute (or make up) the implant's material volume. The material volume occupied by the multiple strands 101 may be 5% to 70% (or, for example, 50% to 70%, or, for example, 50% to 60%) of the total static implant volume. Additionally, or if desired, the implant's gaps 106 may constitute (or include) 30% to 95% (or, for example, 30% to 50%, or, for example, 40% to 50%) of the total static implant volume. Of the material volume of the implant's three-dimensional structure 102, the implant's multiple sidewalls 104 may constitute (or include) 80% to 100% of the material volume. The remainder of the implant's material volume not formed by the multiple sidewalls 104 may be contributions from, for example, contour lines and / or surface filler lines. Optionally, the strand segments 105 of a sidewall 104 may constitute (or make up) less than 90% (or, e.g., less than 50%, or, e.g., 50%-70%, or, e.g., 50%-60%) of the sidewall 104, with the remainder of the sidewall 104 being occupied by gaps 106. Optionally, at least 80% (or, e.g., at least 95%, or, e.g., 100%) of all sidewalls 104 of the plurality of sidewalls 104 may include reversibly expandable gaps 106. Additionally, or optionally, at least 50% (or, e.g., at least 60%, or, e.g., at least 70%) of all gaps 106 of the implant 100 are reversibly expandable gaps.

[0029] As shown in FIG. 1A, the implant 100 may form (or be fabricated into) a three-dimensional structure 102, which may be a mesh-like structure or a scaffold structure. For example, a plurality of strands 101 (or lines) may be configured to form a mesh-like three-dimensional structure 102. The three-dimensional structure 102 may define (or have) a rest volume of the implant 100. The rest volume (cm) of the implant 100 may be 3) may be the volume of the implant 100 before insertion of the implant 100 into a patient to build and / or reconstruct soft tissue. The rest volume of the implant 100 may be the volume of the implant 100 in a resting state. The implant 100 in a resting state may be an implant in a state in which only one outer surface of the implant 100 (e.g., outer surface 108) is subjected to an external force, such as when the implant 100 is resting on (or in contact with, or sitting on) a carrier surface (e.g., a table surface, or, e.g., a board). For example, the implant 100 in a resting state may mean that the first outer surface 108 of the implant may be in contact with the carrier surface, and the second (opposing) outer surface 109 may not be subjected to any tensile and / or compressive forces. In other words, the rest volume of the implant 100 may be the volume of the implant 100 in a state in which no opposing compressive or tensile forces are acting on the surface of the implant. The rest volume of the implant 100 may be derived based on the build volume (desired or required volume) of the implant 100 to be inserted into a patient. For example, if desired, implant 100 may be configured to be compressible below the build volume such that implant 100 constitutes or reaches the build volume after insertion into the patient.

[0030] The plurality of strands 101 may be a plurality of wires or cord-like materials. The strands 101 (or lines, or filaments) may have a length and a cross-sectional diameter d. The diameter of the strands 101 may be an average dimension of the strands 101, such as the smallest cross-sectional dimension of the strands 101. Optionally, the length of the strands 101 may be greater than the diameter of the strands 101 (e.g., at least 5 times greater, or at least 10 times greater, or at least 20 times greater). The strand diameter may be, for example, between 300 μm and 350 μm, as desired.

[0031] The term hollow channel 103 may refer to a channel in which at least 70% (or, e.g., at least 80%, or, e.g., at least 90%) of the channel volume enclosed by the sidewalls of the channel is unfilled or unoccupied by material such as strand segments or strands. For example, hollow channel 103 may not necessarily be limited to being a channel that is completely (100%) unfilled.

[0032] The three-dimensional structure 102 may include multiple substantially planar layers (e.g., parallel to the xy plane) sequentially arranged or stacked on top of each other in the z-direction 107 (e.g., vertical direction). Optionally, each planar layer may include multiple strands 101 forming a two-dimensional lattice array of unit cells. The individual layers of the implant 100 may be sequentially arranged (stacked and / or above and below each other) such that the unit cells of successive layers (formed on top of each other) may form multiple hollow channels 103. Each channel 103 may be formed from (or may include) columns of unit cells from successive layers stacked on top of each other. For example, in the implant 100 shown in FIGS. 1A-1C, the implant 100 may include multiple layers of primarily square-shaped unit cells arranged on top of each other to form hollow channels 103 having square cross-sections. If desired, the unit cell may be regularly repeated throughout 50% or more (or, for example, 80% or more, or, for example, 90% or more, or, for example, 95% or more) of the quiescent volume of the three-dimensional lattice structure 102. Thus, the lattice structure 102 may include multiple adjacent (e.g., directly adjacent) unit cells connected to one another throughout the lattice structure 102. A unit cell may be the smallest and most fundamental unit of the three-dimensional lattice structure 102.

[0033] Optionally, each planar layer of the unit cell may include a first sublayer (or first sublayers) including strands oriented in a first direction and an adjacent second sublayer (or second sublayers) including strands oriented in a second direction different from the first direction.

[0034] FIG. 1D illustrates a first sublayer 115 of the implant 100, which includes strands 101 oriented in a first direction (e.g., the y-direction). FIG. 1E illustrates a second sublayer 116 of the implant 100, which includes strands 101 oriented in a second direction (e.g., the x-direction). Optionally, the strands 101 within each sublayer may be parallel to one another (e.g., acute angles between strands within a sublayer, or optimal for sinusoidal strands, may be within ±5°). The strands 101 of the first sublayer 115 and the second sublayer 116 may intersect at intersections or intersection regions to form a two-dimensional lattice array of sublayers. Optionally, the strands 101 of (or, for example, within) each sublayer 115, 116 may be part of a continuous strand that meanders continuously from the start point S of the sublayer to the end point E of the sublayer. For example, optionally, the strands of the first sublayer 115 may be part of a continuous sublayer strand that meanders continuously from the start point S of the first sublayer to the end point E of the sublayer. Optionally, the strands of the second sublayer 116 may be part of a continuous sublayer strand that meanders continuously from the start point S of the second sublayer to the end point E of the second sublayer. The continuous strands of the sublayers may have multiple straight portions oriented in a first direction. The multiple straight portions of the sublayers may be connected by meandering portions. The meandering portions may be formed at least partially at the boundary or perimeter of the layer and may also form sidewalls of surface filler lines or channels at the surface of the implant. Each sublayer can have its own boundary or perimeter along which the meandering portions (or surface filler lines) are formed. If desired, the strands may be straight strands, or alternatively, the strands may be sinusoidal zig-zag strands, and the unit cell may have a "free-form" shape.

[0035] The first sublayer 115 and the second sublayer 116 may be arranged such that their respective strands 101 intersect to form a two-dimensional lattice array of unit cells. The intersecting strands 101 of the first sublayer 115 and the second sublayer 116 may be arranged such that each unit cell formed from the intersecting strands may include a pore having a pore diameter or may be referred to as a pore having a pore diameter. The intersecting strands may form or define the geometry (e.g., shape, dimensions, pore diameter) of the individual unit cells. Each two-dimensional unit cell may have a pore diameter that defines the dimensions of the unit cell. The pore diameter of a two-dimensional unit cell may be described in terms of its diameter, width, and / or pore area; for example, the pore diameter w of a unit cell of a layer may be referred to as the diameter or width of a hollow channel 103 (as shown in FIG. 1A). Optionally, the average pore size of the plurality of unit cells of the three-dimensional structure 102 may be at least 0.5 mm (or, e.g., at least 0.75 mm, or, e.g., at least 0.8 mm, or, e.g., at least 1 mm, or, e.g., at least 1.5 mm, or, e.g., at least 2 mm, or, e.g., at least 5 mm). The pore area of ​​at least 25% (or, e.g., at least 70%, or, e.g., at least 80%) of the surface pores of the three-dimensional structure 102 may be at least 0.75 mm. 2 (or e.g. at least 1 mm 2 , or for example at least 3 mm 2 The surface pore area may be the area enclosed by the intersecting strands that define the surface pore.

[0036] The plurality of two-dimensional unit cells may be polygonal, triangular, diamond, rhombic, square, elliptical, sinusoidal, and / or hexagonal. The implant 100 may optionally include unit cells having predominantly (e.g., 50% or more, or, e.g., 60% or more, or, e.g., 70% or more, or, e.g., 80% or more) one of these shapes throughout the volume of the implant 100; alternatively, it may be understood that the implant 100 may include unit cells having a variety of different shapes. The sidewalls 104 of the hollow channel 103 may be formed from a plurality of strands 101 lying substantially parallel to the xy plane, stacked perpendicular to the z direction (third direction), and oriented in substantially the same direction. The sidewalls 104 of the hollow channel 103 may be arranged so that the cross-sectional shape of the hollow channel 103 is any one of the following shapes: polygonal, triangular, diamond, rhombus, square, elliptical, sinusoidal, and hexagonal.

[0037] Compared to pores, gaps 106 of implant 100 may (or may be) refer to the smallest spacing between any adjacent strands forming hollow channel 103. For example, gaps 106 may have the smallest area enclosed by the strands of the implant (e.g., the smallest gap area) compared to the pore area of ​​the unit cell. Optionally, the gap area of ​​gap 106 (which may be the area enclosed by two pairs of opposing strands defining gap 106) may be less than 50% (or, e.g., less than 40%, or, e.g., less than 30%) of the pore area.

[0038] Each hollow channel 103 may extend along its longitudinal axis. The longitudinal axis may be a line including the midpoint of the sidewall of the hollow channel 103. The hollow channel 103 may extend, for example, between the first outer surface region 108 and the second outer surface region 109 of the three-dimensional structure 102. The channels 103 of the plurality of hollow channels 103 (e.g., each channel, or, for example, one or more channels 103, as needed) may be configured to extend from the first outer surface region 108 toward the second outer surface region 109. The exact position and / or angle of inclination of the plurality of hollow channels 103 can be configured according to the patient's needs. If needed, the plurality of hollow channels 103 may be parallel to one another (e.g., the acute angle between the sidewalls of adjacent channels may be within ±5°). Alternatively, the plurality of hollow channels 103 may converge toward a convergence region (or point), which may be located outside the first exterior surface region 108 or the second exterior surface region 109. Optionally, the hollow channels 103 may include zigzag channels, inclined channels, and / or tapered channels. Optionally, the hollow channels 103 may be inclined relative to the first exterior surface region 108. For example, among unit cells forming a column of unit cells, a unit cell of a second layer may have a lateral offset (in the x or y direction) relative to an adjacent unit cell of the first layer. The lateral offset between the first and second unit cells may be 0% to 50% (or, for example, 0% to 20%, or, for example, 5% to 10%) of the pore diameter of the unit cell. Optionally, within the same column, each unit cell of each layer may have the same lateral offset relative to the unit cell of the immediately preceding layer. Optionally, at least 80% (or e.g., at least 70%, or e.g., at least 50%) of the unit cells of the same column (forming the same channel) may have the same pore size and the same pore shape. Alternatively, in the case of tapered channels, the unit cells forming the same channel may have different pore sizes (e.g., the pore sizes of the unit cells may decrease or increase toward one of the outer surface regions).

[0039] The plurality of strands 101 may be configured such that the gap 106A is reversibly expandable even when the implant is at rest and / or when the implant 100 is compressed. When a compressive force (physical or mechanical) is applied to the outer surfaces of the implant 100, the implant 100 is compressible to less than 80% (or, for example, less than 70%, or, for example, less than 60%, or, for example, less than 50%, or, for example, less than 30%, or, for example, between 30% and 95%, or, for example, between 45% and 80%, or, for example, between 45% and 70%, or, for example, between 80% and 95%) of its resting volume.

[0040] The expandability of the implant gap can be described with reference to the deflection of a beam. The implant gap is expandable, meaning that the strands are capable of deflecting and / or bending without breaking in response to one or more forces acting on the strands such that the gap height between two adjacent strand segments increases. The bending stress σ of a beam (or strand segment) that simply bends in response to an applied external force can be expressed as:

number

[0041] Such a beam is simply supported at both ends, as shown in Figure 1F. The bending moment is the reaction that occurs in a beam when an external force or moment is applied to the beam. σ is the bending stress; M is the bending moment; C is the distance from the neutral axis; and I is the moment of inertia of the cross section of the beam. The maximum bending moment M that can be produced by a load applied midway between the supports can be described or defined by the following equation:

number

[0042] where L is the length of the beam and F is the force acting on the beam. Maximum bending stress σ maxcan be expressed as follows:

number

[0043] M is the maximum bending moment, and C max is the maximum distance from the neutral axis. I is the moment of inertia of the cross section of the beam. The deflection δ of a central load on a beam with two simple supports is given by

number

[0044] where L is the length of the beam, F is the applied force, E is Young's modulus, and I is the moment of inertia of the beam. Considering implant 100, the deflection capacity δ of the implant's strands can result in gap widening. The deflection capacity may reflect or be itself a desired deflection capacity of the strands and / or a desired expandability of the gap height (e.g., how far the gap is expected to widen).

[0045] FIG. 1G shows an illustration of the implant shown in FIG. 1C. As shown in FIG. 1G, insertion of a needle 155 into the gap can exert one or more forces 113, 114 on the implant. The needle can have a diameter nd greater than the baseline gap height gh. The gap length can be represented by gl, which can be the length of the strand segment between the center of the first strand 105B and the center of the second strand 105C. The first and second strands 105C can function as simple supports for adjacent strand segments 105 in the gap.

[0046] The insertion of the needle results in a deflection δ in each of two consecutive strand segments 105A. Each strand segment 105A can behave like a beam with two simple supports 105B, 105C, which are subjected to bending stress. The deflection of the adjacent strand segment 105A caused by the insertion of the needle can be represented by the dotted line. The deflection can be expressed as:

number

[0047] The maximum bending stress in the strand, which may be subjected to forces such as those caused by the insertion of needle 155, is given by:

number

[0048] R may be the radius of the strand (e.g., d=2×R).

[0049] Using equations (3) and (4),

number

[0050] and the maximum stress σ max The following formula is obtained.

number

[0051] For elastic deformation, σ max The value of σ is the yield strength of the strand material. yield Therefore, we can apply the rule that

number

[0052] The deflection capacity δ can be expressed by the following formula:

number

[0053] The reversibly expandable gap 106 may be expandable to 110%-250% of the baseline gap height gh. This can occur when the needle diameter nd is 110%-250% of the baseline gap height gh. These parameters can be expressed by the following equation:

number

[0054] and,

number

[0055] E and σ yield are the material properties of the strand material of the implant 100. The radius of the strand, R, and the length of the strand segment between the two supports 105B, 105C, gl, are the geometric characteristics of the strand of the implant 100. Equation (10) can be obtained based on equation (7).

number

[0056] 1G in a zx cross section. In some instances, the lateral offset of one strand segment 105A relative to its adjacent strand segment 105A in the next layer is equal to 0 along the xy plane (or horizontally) (offset=0). In these cases, the baseline gap height gh may simply be equal to the average strand diameter d or 2R.

[0057] Alternatively, as shown in Figure 1I, the lateral offset of one strand segment 105A relative to its adjacent strand segment 105A in the next layer along or parallel to the xy plane may be greater than 0. In such a case, the gap height gh can be expressed as:

number

[0058] lt may be referred to as the layer thickness. The dimension 2×lt may be the distance measured in the z-direction between the midpoint of a first strand segment 105A and the midpoint of a second adjacent strand segment 105A. The dimension 2×lt may be the offset in the z-direction, while the lateral offset may be the offset in the x- or y-direction. The lateral offset value between adjacent strand segments may be 0% to 99% (or, for example, 0% to 50%, or, for example, 0% to 10%) of the gap length gl.

[0059] 2A and 2B show a perspective view and a side cross-sectional view, respectively, of implant 200 for insertion into a patient. Implant 200 may include one, more, or all of the features described in connection with FIGS. 1A-1E. Implant 200 may have different dimensions compared to implant 100, such as a different gap height / gap length ratio. For example, baseline gap height gh may be similar to baseline gap length gl (e.g., 95%-100% of the baseline gap length).

[0060] The implants 100, 200 may be any type of implant suitable for insertion into a living subject, such as a human or animal body. The implants 100, 200 may be skeletal implants for bone tissue, or implants for any soft tissue portion of a human or animal body. The implants may be breast or pectoral implants (the latter may be used for treating pectoral muscle deformities such as pectus excavatum), or implants for other parts of the body, such as the buttocks (also known as hips), calves, cheeks, or other facial areas, or testicular implants. It should be noted in this context that pectoral muscle deformities such as pectus excavatum can affect both men and women, and thus pectus excavatum in both male and female subjects can be treated with the implants of the present invention. In line with the above, the implants of the present invention may take any suitable form, depending solely on the tissue to be reconstructed or augmented. The implants may, for example, have the form of a buttock implant, as described in U.S. Pat. No. 10,004,585. Depending on the type of implant required, the geometry of the implants 100, 200 (eg, the size and / or shape of the implant) may be tailored to meet the criteria required for the implant.

[0061] 3A shows a perspective view of an implant 300 suitable for use as a breast implant. The implant 300 may include one or more or all of the features of the implants described in connection with FIGS. 1A-2B. Although the implant 300 is described with respect to a breast implant, such an implant may also be useful in other areas of the body, such as the chest, buttocks, calves, or areas of the face, such as the cheeks (see above).

[0062] As shown in FIG. 3A, implant 300 includes a plurality of strands 101 that form a three-dimensional structure 302. Three-dimensional structure 302 includes a plurality of hollow channels 103. Each hollow channel 103 includes a plurality of sidewalls 104. Sidewalls 104 include a plurality of strand segments 105 and a plurality of gaps 106 that are alternately arranged such that gaps 106 are formed between adjacent strand segments 105 of sidewalls 104. Gaps 106 are reversibly expandable gaps.

[0063] The three-dimensional structure 302 of the implant 300 may include a first outer surface region 308 and a second (different and / or opposing) outer surface region 309. An outer surface region may be understood to refer to (or may be) the outermost surface, outermost layer, and / or outermost contour of the implant 300. The outermost surface and outermost contour may be formed from one or more layers or lines. An outer surface region may refer to (or may be) the outermost layers of the implant 300 (e.g., a single outermost layer, or, for example, multiple outermost layers). An outer surface region may refer to the surface of the implant 300 that faces the exterior.

[0064] The first outer surface region 308 of the implant 300 may include or have a first surface curvature. The first outer surface region 308 of the implant 300 may be the most planar (or, for example, flattest) surface of the implant 300. For example, the first outer surface region 308 may be the flattest surface of the implant and / or the surface having the least amount of curvature. As shown in FIG. 3A , the first outer surface region 308 of the implant 300 may be substantially parallel to a two-dimensional (xy) Cartesian plane. Alternatively, or if desired, the best-fit plane of the first outer surface region 308 may be parallel to the two-dimensional (xy) Cartesian plane.

[0065] The second outer surface region 309 may have a geometry (e.g., shape, curvature, size) that represents the shape of the patient's breast that will be constructed with the implant 300. The second outer surface region 309 of the implant 300 may include or have a second surface curvature that is different from the first surface curvature. The second surface curvature may be greater than the first surface curvature. The second outer surface region 309 of the implant 300 may be contiguous (e.g., adjacent) to the first outer surface region 308 of the implant 300 around a perimeter 317 (e.g., periphery) of the first outer surface region 308. For example, the second outer surface region 309 of the implant 300 may abut the first outer surface region 308, and the perimeter 317 of the first outer surface region 308 may be a shared edge (or interface) between the first outer surface region 308 and the second outer surface region 309. Additionally or optionally, the second outer surface region 309 may include an apex region 318 at the second outer surface region 309. The location (or position) of the apex region 318 on the second outer surface region 309 of the implant may be based on (and / or may correspond to) the location (or position) of the nipple / areola of the breast created by the implant 300.

[0066] Optionally, the acute inclination angle between one or more sidewalls and a reference axis (e.g., x-axis) representing the first exterior surface region may be less than 90° (or, for example, less than 60°). The reference axis may be based on a plane or a best-fit line of the first exterior surface region 108. Optionally, or alternatively, the acute inclination angle between one or more sidewalls 104 and the reference axis may be approximately 90° (e.g., the channels may be vertical channels, as shown in Figures 1A-2B). The plurality of hollow channels 103 may be comprised of 5 to 1000 hollow channels (or, for example, 5 to 60 channels, or, for example, 8 to 20 channels).

[0067] The three-dimensional structure 302 of the implant 300 may be a reversibly compressible three-dimensional structure 302. For example, the individual unit cells of the implant 300 may be spring-like unit cells. The spring-like unit cells may be compressible to at least 80% (or, e.g., at least 70%, or, e.g., at least 60%, or, e.g., at least 50%, or, e.g., at least 30%) of their original volume. By being reversibly compressible, each unit cell is able to recover or return to its original (resting) volume after a compressive force is removed (even at the same ambient pressure and temperature). The reversibly compressible spring-like unit cells may be configured to recover to 80%-100% (or, e.g., 95%-100%, or, e.g., 98%-100%) of their original volume after a compressive force applied to the implant 300 is removed.

[0068] The softness of the implant 300 can be expressed by the c value, which can be expressed by the following formula:

number

[0069] F 20% is the force value (N) at 20% compression, F 10% is the force value (N) at 10% compression, and ε 10% is the strain value at 10% compression, and ε 20% is the strain value at 20% compression. The c value representing the softness of the implant 300 may be, for example, 20N to 190N (or, for example, 20N to 150N, or, for example, 30N to 100N, or, for example, 30N to 40N).

[0070] The material density ρ of the implant 300 is 0.1 gr / cm 3 ~2gr / cm 3 (or e.g. 0.1gr / cm 3 ~1gr / cm 3 , or for example 0.1gr / cm 3 ~0.5gr / cm 3) The material density can be determined by dividing the weight of the implant 300 by the resting volume of the implant prior to insertion into the patient. By comparison, the material density of silicone is 0.98 gr / cm 3 The material density of saline is 1.005gr / cm 3 Thus, the weight of implant 300 may be 10%-20% (or, for example, 10%-15%) of its volume in milliliters, or 10%-20% (or, for example, 10%-15%) of a conventional non-porous silicone / saline implant (whose weight in grams is approximately the same as its volume in milliliters). As an example, implant 300 having a volume of 250 ml weighs 25 g, whereas a conventional silicone implant having a volume of 250 ml weighs 240 g, and a saline implant having a volume of 250 ml weighs 250 g. One, more, or all of these features result in an implant with a lightweight framework, which can achieve a weight reduction of 90% compared to conventional implants.

[0071] The strands 101 of the implant 300 may be formed from a polymeric material, such as a surface degradable polymer. A surface degradable polymeric material may include or be a polymeric material that degrades primarily via a surface degradation mechanism, as opposed to bulk degradation. The strands 101 may include, be formed from, or be made from a biodegradable material. The biodegradable material may be selected from the group consisting of polycaprolactone, poly(1,3-trimethylene carbonate), polylactide, polyglycolide, poly(ester amide), poly(ethylene glycol) / poly(butylene terephthalate), poly(glycerol sebacate), poly(1,8-octanediol-co-citric acid), poly(1,10-decanediol-co-D,L-lactic acid), poly(diol citrate), poly(glycolide-co-caprolactone), poly(1,3-trimethylene carbonate-co-lactide), poly(1,3-trimethylene carbonate-co-caprolactone), and copolymers of at least two of these materials. Optionally, the biodegradable material may be polycaprolactone. Optionally, the biodegradable material may be a copolymer of polycaprolactone and either poly-trimethylene carbonate or polylactide. Alternatively, the plurality of strands 101 may comprise a non-degradable material such as nylon. The thickness (or diameter) of the plurality of strands 101 may be selected so that the strands are flexible. Bulk PCL may have, for example, an elastic modulus (E) of 216 MPa, a tensile strength of 10 MPa, and a stress at break of 26.5 MPa.

[0072] Equation (10) above can be applied to the design of the implants described herein. 2 can be selected based on the material properties (such as Young's modulus and yield strength) of the material from which the implant is made and the desired deflection capacity δ based on surgical requirements, such as the size of the needle used by the surgeon.

[0073] For example, the material used to form implant 300 may have an elastic modulus of 270 MPa and a yield strength σ of 12.5 MPa. yield The needle used may have a diameter of 2 mm.

[0074] Geometric characteristics associated with the implant may be selected, such as lateral offset, layer thickness, radius, and gap length. For example, the lateral offset may be 1 mm, the layer thickness lt may be 0.2 mm, the radius R may be 0.175 mm, and the gap length gl may be 6 mm.

[0075] Using equation (11) above, the value of the gap height can be calculated or determined, where

number

[0076] Using equation (8) above, the value of the deflection capacity can be calculated or determined, where:

number

[0077] Using the above formula (10), R / gl 2 Calculating the upper limit of

number

[0078] Additionally or optionally, the implant 300 may further include a plurality of contouring strands 319 disposed on an outer surface region of the implant 300 (eg, on the second outer surface region 309).

[0079] 3B and 3C show perspective side and top views of an implant 300 further including a plurality of contouring strands 319 and surface filler strands 322. FIG.

[0080] As shown in FIGS. 3B and 3C , the plurality of strands forming the implant 300 may include a plurality of contouring strands 319 and surface filler strands 322. Each contouring strand 319 may form a semi-contour around the second outer surface region 309. The semi-contour of the contouring strand 319 may extend only partially (e.g., 30% to 80%, or, for example, 40% to 70%, or, for example, 50% to 70%) around the layer. The plurality of contouring strands 319 may be arranged consecutively (e.g., consecutively) between the first outer surface region 308 and the apex region 318. The plurality of contouring strands 319 may further be arranged such that adjacent contouring strands 319 are separated by a reversibly expandable gap 106. For example, the reversibly expandable contouring gap 106 may be formed between adjacent strand segments of the plurality of contouring strands 319.

[0081] As shown in FIG. 3D , the implant 300 may further include surface filler strands 322 formed on the outermost surface of the three-dimensional structure 302. Optionally, the multiple surface filler strands 322 may be arranged in columns 323 (or strips) in the second outer surface region. Each surface filler column 323 may include multiple surface filler strands 322 and multiple reversibly expandable surface gaps. Each reversibly expandable surface gap may be formed between adjacent surface filler strands 322 in the column 323. The surface filler columns 323 may be arranged adjacent to open columns 324. The open columns may include (or be) surface columns that do not include surface filler portions. Optionally, the multiple surface filler columns 323 and the multiple open columns 324 may be arranged alternately in the outer surface region (e.g., the second outer surface region 309). Optionally, the multiple surface filler columns 323 and the multiple open columns 324 may be arranged in a cross shape in the outer surface region.

[0082] A plurality of hollow channels 103 may extend through the bulk of the implant 300. Adjacent strand segments may be separated by a reversibly expandable gap.

[0083] The implant 300 can be inserted into the breast patient's area. After the implant 300 is inserted into the patient, fat injection may be required. This may be necessary because the regenerated tissue that "regrows" inside the implant has been observed to be harder than natural breast tissue. Therefore, to achieve a final state as soft as natural breast tissue, an appropriate percentage of fat can be collected, for example by liposuction, and injected into the implant 300 using a specific cannula (or needle). The reversibly expandable gap 106 of the implant 300 allows for avoiding problems with the injection procedure (e.g., injections that perforate the structure multiple times, damaging strands and affecting the integrity of the entire structure of the implant 300).

[0084] The implant 300 may be an implant for use in guiding a needle through the implant for an implant procedure. The implant 300 may be configured to receive an elongated object (such as a needle for fat injection) within the bulk of the three-dimensional structure 302. The elongated object may have a diameter greater than the baseline gap height gh of the gap 106 of the implant. For example, the diameter of the elongated object may be 110% to 250% of the baseline gap height gh of the gap 106 of the implant. Furthermore, the elongated object may have a length greater than at least two times (or five times, or ten times) the width of the hollow channel. The multiple strands may be configured such that the height of the gap 106 increases when the object is received by the gap, and decreases when the object is removed from the gap 106. Such needles or cannulas may have a diameter of at least 0.8 mm (or e.g., at least 2 mm, or e.g., at least 4 mm, or e.g., between 0.8 mm and 4 mm, or e.g., between 0.8 mm and 3 mm) and a length of at least 2 cm. 80% or more (or e.g., 90% or more, or e.g., all) of all gaps in implant 300 having a baseline gap height of less than 1 mm may be reversibly expandable gaps.

[0085] FIG. 4A shows implants 100, 200, and 300 without a reversibly expandable gap.

[0086] Unlike implants 100, 200, and 300 with reversibly expandable gaps 106, the implant of FIG. 4A requires the surgeon to insert the fat injection needle into a precise location. For example, after inserting the implant into a patient, the surgeon must visually locate the implant's largest openings. These largest openings may be channel pores that define the channel ends, and their pore area may be at least two times larger than the gap area. The surgeon must then insert the needle into the pores precisely along the channel length (e.g., along the longitudinal axis of the channel). If the surgeon cannot visually locate the channel ends, or if the surgeon inserts the needle into the implant at an angle that is not aligned with the channel length, or if the surgeon inserts the needle into the sidewall of the channel, injection from the needle may damage the implant strands and / or the implant's three-dimensional structure.

[0087] FIG. 4B shows an image of inserting a cannula for fat injection into the implant 300. The implant 300 allows a surgeon to blindly insert a needle into the implant 300 from anywhere on the implant (e.g., any surface). The implant 300 with the reversibly expandable gap 106 allows a needle to be inserted into the breast implant from any direction at the second outer surface region 309 of the implant and / or through any sidewall 104 within the bulk of the implant 300. The needle may be inserted initially through the bulk internal structure of the implant 300 from an insertion region of the implant 300. The insertion region may be a randomly selected region of the implant. The needle may be inserted such that it crosses and / or enters several (e.g., multiple) hollow channels 103 simultaneously and penetrates several (e.g., multiple) sidewalls. In other words, the needle may be inserted through multiple hollow channels 103 simultaneously. The needle can then be withdrawn from the implant 300 in a stepwise fashion over multiple withdrawal steps. After each withdrawal step, fat can be injected from the needle into the implant. This alternating process of needle withdrawal and fat injection is repeated until the needle is completely withdrawn from the implant. This process, beginning with blind injection, may be performed repeatedly from multiple random insertion areas. The number of times this process is performed (e.g., at least 20 times, or at least 30 times, or at least 60 times) may be based on the number of injections and / or the amount of fat injection required. Frequent needle insertions may be required during surgery. The implant 300 allows for an expedited surgical process, as the surgeon no longer needs to visually locate each channel and opening before inserting the needle, but can instead perform a blind insertion. Additionally, the implant 300 allows for a cannula to penetrate multiple sidewalls 104 and channels 103 simultaneously, which may also expedite the surgical process.Furthermore, because the gap 106 can accommodate the entry of the cannula, neither the implant 300 nor the cannula will be damaged. Thus, the inserted implant 300 has improved structural integrity compared to an implant 300 that does not implement a reversibly expandable gap.

[0088] FIG. 4C shows an example of an insertable region for multi-injection testing. A certain number of injections (e.g., 60 injections) can be divided into three broad injection sites (431, 432, 433). For example, 20 injections may be performed across each region. Injections (e.g., needle insertion) may be performed such that the needle is inserted at any angle relative to the first exterior surface region 308 of the implant. For example, the needle may be inserted flat or at an oblique or oblique angle relative to the first exterior surface region 308.

[0089] The strands 101 may be configured to allow the gap 106 of the implant 300 to be reversibly expandable both when the implant is at rest and when the implant 300 is compressed (e.g., while the implant 300 is in the body). A compressed implant may be an implant that is compressed to less than 90% (or, e.g., less than 70%, or, e.g., less than 60%, or, e.g., less than 50%, or, e.g., less than 30%) of its resting volume. The height of the gap 106 may increase to greater than 110% (or, e.g., greater than 150%, or, e.g., greater than 200%, or, e.g., between 120% and 250%, or, e.g., between 120% and 200%) of the baseline gap height gh and / or the average strand diameter d, depending on the object accommodated by the gap 106. The reversibly expandable gap 106 may be configured to recover or return to (or decrease to) at least 110% (or, e.g., at least 105%, or, e.g., 100%, or, e.g., 80%-115%, or, e.g., 90%-110%) of its original gap height and / or average strand diameter d upon removal of the object from the gap 106.

[0090] To accommodate each needle insertion, the plurality of strands 101 may be arranged such that the reversibly expandable gaps 106 of at least two (or, e.g., two or more, or, e.g., three or more, or, e.g., five or more) consecutive hollow channels are simultaneously expandable by objects simultaneously received by the gaps of the at least two consecutive hollow channels. The plurality of strands 101 may be arranged such that the reversibly expandable gaps 106 of at least two (or, e.g., two or more, or, e.g., three or more, or, e.g., five or more) distinct sidewalls 104 of the implant 300 are simultaneously expandable by objects simultaneously received by the gaps of the at least two (or, e.g., two or more, or, e.g., three or more, or, e.g., five or more) distinct sidewalls. The expansion of the gaps 106 may occur without increasing or changing the overall resting volume (or build-up volume) of the implant 300. In other words, the reversibly expandable gaps may be configured to expand while the overall volume of the implant 300 remains constant or even under compression.

[0091] The surgeon inserting the needle should be able to penetrate the bulk of the implant without damaging the structure. For example, the filament surrounding the gap should be able to bend, stretch, or move out of the way without breaking. Furthermore, the surgeon only needs to exert a force of 50 N or less (or, for example, 2 N to 50 N, or, for example, 5 N to 20 N, or, for example, 5 N to 10 N) to insert the needle through the gap. For example, upon receiving a force of 10 N from an injection needle, the filament reversibly deforms (lengthens, stretches, or moves) to allow the needle to pass through the gap. The material itself can be selected so that the filament does not break at this stretch point.

[0092] Figure 4D shows the stress-strain curves of strands made from different materials, including stainless steel, polylactic acid plastic PLA, and polycaprolactone PCL.

[0093] The break point of a stainless steel strand can be 32% strain under a stress of 720 MPa. A PLA strand can break at a strain of 5% when stressed at 40 MPa. A PCL strand has a strain-to-break value of 460% (under a stress of less than 50 MPa), about 15 times that of a stainless steel strand and about 70 times that of a PLA strand. Because of its high break strain, PCL can accept large deformations, meaning it can stretch at least four times its original length.

[0094] The material for forming the plurality of strands may be selected to have a break point on a stress-strain diagram where the strain at break is greater than 30% and the stress at break is less than 250 MPa.

[0095] The material of the implant strands exhibits stress-strain behavior similar to PCL. For example, the break point on the stress-strain diagram may be greater than 30% (or, e.g., greater than 100%, or, e.g., greater than 200%, or, e.g., greater than 300%, or, e.g., greater than 400%), and the stress may be less than 50 MPa, or between 10 MPa and 250 MPa (or, e.g., between 10 MPa and 100 MPa, or, e.g., between 10 MPa and 50 MPa, or, e.g., between 10 and 30 MPa). Optionally, the break point of a strand in a plurality of strands may be greater than 30% (or, e.g., greater than 100%, or, e.g., greater than 200%, or, e.g., greater than 300%, or, e.g., greater than 400%), and the corresponding stress may be less than 50 MPa (or, e.g., between 10 MPa and 250 MPa, or, e.g., between 10 MPa and 100 MPa, or, e.g., between 10 MPa and 50 MPa, or, e.g., between 10 and 30 MPa).

[0096] For example, when the distance between two adjacent strands varies between 0.56 mm and 1.84 mm and the needle diameter is 2 mm, PCL can easily deform during needle penetration into the wall without reaching the breaking point, whereas PLA and stainless steel cannot withstand such deformation and reach the breaking point during needle penetration.

[0097] 5A shows an implant such as implant 300 after a sham surgery. During the sham surgery, implant 300 was inserted into a pig. Implant 300 was blindly (randomly) injected with fat. Upon removal, the three-dimensional skeletal structure 302 of implant 300 was shown to be filled with fat and to be evenly distributed despite the blind (random) injection.

[0098] Figures 5B, 5C, and 5D show images of the implant 300 after blind injection, respectively. Figure 5C shows that fat is evenly distributed throughout the implant 300. White represents fat, and black represents air. Mechanical testing (e.g., tensile, compression, and shear tests) was performed to evaluate changes in the dimensions and / or mechanical properties of the scaffold before fat injection. Tensile tests (by friction) were performed for 11,112 cycles at a frequency of 0.4 Hz, and the results confirmed that the dimensions (width, projections, and height), softness (c value), and shear strength (Fmax) of the scaffold remained within the implant's specifications. In other words, the tensile strength of the implant 300 was not compromised. Comparing the softness index (which is a good indicator of scaffold integrity) after testing with the results before testing, only a decrease of approximately 10% was detected. Therefore, although the scaffold experienced a reasonable and expected loss in mechanical properties, the integrity of the scaffold was not affected.

[0099] FIG. 6 shows a flow chart of a method 600 for forming an implant of the present invention.

[0100] The method 600 includes forming 620 a plurality of strands to form a three-dimensional structure. The plurality of strands has a yield strength (σ yieldThe three-dimensional structure is formed from a material having a radius (R) and a modulus of elasticity (E). The three-dimensional structure includes a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. The sidewalls include a plurality of gaps and a plurality of consecutive strand segments of a plurality of strands. The strand segments and the gaps are alternately arranged such that gaps are formed between adjacent strand segments of the sidewalls, the gaps being composed of a gap length (gl) and a static gap height (gh). The plurality of gaps are reversibly expandable gaps. Adjacent strand segments of a reversibly expandable gap have a deflection capacity (δ) in response to an object being received by the gap such that an increased gap height is achieved between the adjacent strand segments. In response to an object being removed from the gap, the gap returns toward the static gap height. The radius (R) of the plurality of strands and the gap length (gl) of each of the plurality of gaps are based on the yield strength and modulus of elasticity of the material.

[0101] Step 620 of forming the plurality of strands may include sequentially printing multiple layers, where the layers comprise a lattice array of two-dimensional unit cells. The multiple layers may be arranged such that the aligned unit cells of successive layers of the multiple layers form hollow channels of the plurality of channels. The implant may be formed by sequentially forming layers (or 3D printing, for example, by fused deposition modeling) to form a three-dimensional (3D) printed scaffold structure. Printing may be performed layer-by-layer in the printing direction (e.g., the z-direction) such that a sequential array of successive layers is formed in the printing direction. Sequentially arranging (by printing) layers on top of each other may result in the formation of a three-dimensional structure in which the edges (or perimeters) of the multiple layers define the shape and / or geometry of the resulting implant. Alternatively, the plurality of strands may be formed by any three-dimensional printing method, such as selective laser sintering (SLS). If desired, the three-dimensional structure may be formed by a printing process based on more than two-dimensional motion, for example, a five-dimensional (5D) printing process or a six-dimensional (6D) printing process.

[0102] Method 600 may optionally further include step 610 of determining at least one of the following parameters (e.g., before step 620 of forming the plurality of strands). The determined parameters may include the number of hollow channels in the three-dimensional structure to be formed, the number of layers in the three-dimensional structure to be formed, and the dimensions of the unit cell to be formed. Further, the determined parameters may include the gap length g l between adjacent strands in a layer and the gap height gh of the gap between adjacent strands in the sidewall of the channel. Further, the determined parameters may include the diameter d of the plurality of strands to be formed.

[0103] The parameter determining step 610 may include determining a deflection capacity (δ) of the reversibly expandable gap based on an object accommodated by the reversibly expandable gap. The parameter determining step 610 may further include determining material properties of the plurality of strands to be formed, the material properties including the yield strength (σ) of the material. yield ) and Young's modulus (E). Step 610 of determining the parameters may further include determining a radius (R) and a gap length (gl) of each strand segment of the plurality of strand segments to be formed. Step 610 of determining the parameters may further include determining the number of hollow channels of the three-dimensional structure to be formed, the number of layers of the three-dimensional structure to be formed, and / or the dimensions of a unit cell.

[0104] After determining the parameters to form a three-dimensional structure containing a reversibly expandable gap, multiple strands may be formed. For example, R / gl 2 ≦σ yield The parameters may be determined such that the dimensional relationship between the number of hollow channels and the layer is 1 / 12Eδ. The three-dimensional structure formed may include at least one of the following parameters: a determined number of hollow channels, a determined number of layers, a determined unit cell dimension, a determined gap length g / between adjacent strands within a layer, a determined gap height gh between adjacent strands within a sidewall of a channel, and a determined diameter of the plurality of strands. The three-dimensional structure formed by method 600 may be any of the three-dimensional structures of implants 100, 200, and 300 described in connection with FIGS. 1A-5C.

[0105] 7A-7G show example implants 700A-700F that include channels with oscillating (e.g., undulating, or e.g., zigzag, or sinusoidal) sidewalls. Implants 700A-700F can include one, more, or all of the features already described in connection with FIGS. 1A-6. For example, implants 700A-700F can include a reversibly expandable gap as described in connection with the implants of FIGS. 1A-6.

[0106] FIG. 7A shows a three-dimensional soft tissue implant 700A for insertion into a patient. The implant 700A includes a plurality of strands 101 forming a three-dimensional structure. The three-dimensional structure includes a plurality of hollow channels 103. Each hollow channel 103 includes a plurality of intersecting sidewalls 134. Each sidewall 134 includes a plurality of alternating strand segments 105 and a plurality of gaps 106. At least one sidewall 134 of the hollow channels 103 is undulating (e.g., an oscillating, zigzag, and / or sinusoidal sidewall). Optionally, each hollow channel 103 may include a first undulating sidewall 134 and a second undulating sidewall 134 facing opposite the first undulating sidewall 134.

[0107] A hollow channel 103 having at least one undulating sidewall can be referred to as an undulating (e.g., zigzag and / or sinusoidal) channel. A (or each) zigzag (or sinusoidal) channel 103 may be a channel in which at least two opposing sidewalls of the channel are disposed relative to one another such that the channel zigzags between a first end 137 (proximal end) of the channel and a second end 138 (distal end) of the channel 103. For example, a zigzag channel 103 may have a first zigzag sidewall 134 and a second zigzag sidewall 134 opposing the first zigzag sidewall. Each zigzag sidewall 134 of the zigzag channel may comprise a plurality of strands 101 arranged consecutively in the z-direction. The strands 101 may be substantially parallel to one another and perpendicular to the z-direction. The consecutively arranged strands 101 of the zigzag sidewall 134 may be laterally offset from one another and arranged to form a pattern of peaks 135 and troughs 136 along the sidewall 134. The strand segments of the contoured sidewall belong to different layers of the implant. Adjacent strand segments of the contoured sidewall are separated by gaps (e.g., the reversibly expandable gaps described in any of Figures 1-6) and are laterally offset from one another to form the pattern of peaks and troughs in the contoured sidewall.

[0108] Each hollow channel is defined by at least three sidewalls that are contiguous with one another. The peaks and troughs of the undulating sidewalls are formed by lateral offsets between adjacent strand segments of the plurality of strand segments of the sidewalls. The peaks and troughs alternate between the first distal end of the channel and the second distal end of the channel.

[0109] An undulating portion (e.g., a zigzag or sinusoidal portion) may also be understood as having a plurality of alternating peaks (maxima) 135 and troughs (minima) 136 from the first end 137 of the channel 103 to the second end 138 of the channel 103 (and / or between the first end 137 of the channel 103 and the second end 138 of the channel 103). These peaks 135 and troughs 136 are visible from a vertical cross section through the sidewall (e.g., through the z-direction). Such a vertical cross section may be perpendicular to the strand direction and may be a cross section through and / or parallel to the channel length.

[0110] The peaks 135 (and / or troughs 136) may be formed from strands of the zigzag sidewall 134 that are arranged such that an angle θ (e.g., θt or θp) is formed between a first plurality of consecutive strands 745 and an immediately adjacent second plurality of consecutive strands 746 in the zigzag sidewall 134. The angle θt may be the angle formed between the first plurality of consecutive strands 745 and the immediately adjacent second plurality of consecutive strands 746 at the troughs of the undulating portion, and the angle θp may be the angle formed between the second plurality of consecutive strands 746 and the immediately adjacent (third) second plurality of consecutive strands at the peaks of the undulating portion. An undulating portion may be one in which θt and / or θp are less than 180°. In contrast, a straight sidewall may have θ equal to 180° along the entire channel length.

[0111] The undulating portion of channel 103 may include at least one θt and / or θp angle that is less than 180°. Optionally, the undulating portion of zigzag channel 103 may include 1 to 1000 (or, for example, 2 to 50, or, for example, 2 to 25) peaks and troughs.

[0112] Figure 7A shows an example of an implant 700A. Figure 7A includes a three-dimensional perspective cross-sectional view (top image) and a two-dimensional cross-sectional view (bottom image) of implant 700A. Implant 700A includes at least one contoured sidewall portion, where the contoured portion is a zigzag portion.

[0113] 7A , the geometries of the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 may be dependent on one another (or, e.g., identical, or, e.g., similar to one another) disregarding manufacturing variations. Use of the term “similar” may be understood to mean that the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 (and / or the zigzag longitudinal axis 742A) may have one or more or all of the same characteristics as one another and / or that the first zigzag sidewall and the second zigzag sidewall may have the same or similar geometries or features over 80% or more (or, e.g., 90% or more, or, e.g., 95% or more, or, e.g., 100%) of the channel length of at least one of the first zigzag sidewall 134 and the second zigzag sidewall 134. One such characteristic may be the number of peaks 135 and troughs 136 along the channel length. Another such characteristic may be the peak-to-trough height, which is the vertical height between a peak and an immediately adjacent trough. Another such characteristic may be the peak-to-peak width, which is between immediately successive peaks. Another such characteristic may be the trough-to-trough width, which is between immediately successive troughs.

[0114] For example, a first zigzag sidewall 134 and an opposing second zigzag sidewall 134 may have a similar pattern of peaks 135 and troughs 136. For example, the θt and θp arrangement of the first sidewall portion 134 may be identical to the θt and θp arrangement of the second sidewall portion 134. Additionally, or optionally, the peaks 135 and troughs 136 of the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 may be positioned relative to one another such that the (minimum or minimum) diameter between the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 along the length of the channel is constant. For example, the (minimum or minimum) diameter between the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 along the length of the channel may have a deviation of less than 10%. Additionally, the zigzag longitudinal axis 742A may have a similar (or the same) geometric shape as at least one of the first zigzag sidewall 134 and the second zigzag sidewall 134 (eg, both sidewalls).

[0115] The first zigzag sidewall portion 134 and the second zigzag sidewall portion 134 may be similar (or identical) along at least 80% (or, e.g., at least 90%, or, e.g., at least 95%, or, e.g., 100%) of the channel length in at least one of the first zigzag sidewall portion 134 and the second zigzag sidewall portion 134. For example, the relative lateral offset (x-direction) between successive strands of the first zigzag sidewall 134 may be the same as the relative lateral offset (x-direction) between successive strands of the second zigzag sidewall 134, ignoring manufacturing variations along at least 80% of the channel length in at least one of the first zigzag sidewall portion 134 and the second zigzag sidewall portion.

[0116] The longitudinal axis may include or be defined by multiple midpoints along the channel length of the channel 103. The multiple midpoints may be midpoints of the (minimum or smallest) diameter dmin between the first and second sidewalls along the channel length. The peaks 135 and troughs 136 of the first and second zigzag sidewalls may be positioned relative to one another such that the zigzag longitudinal axis 742A extends between the first end of the channel and the second end of the channel. The zigzag longitudinal axis 742A may have a similar pattern as the first and second zigzag sidewalls.

[0117] FIG. 7B shows an example of a further implant 700B. FIG. 7B includes a three-dimensional perspective cross-sectional view (top image) and a two-dimensional cross-sectional view (bottom image) of implant 700B. Implant 700B may be similar to implant 700A and may include one, more, or all of the features of implant 700A. However, in implant 700B, second sidewall portion 134 may be a mirror image of first and second sidewall portions 134 about longitudinal axis 742B.

[0118] FIG. 7C shows an example of a further implant 700C. FIG. 7C includes a three-dimensional perspective cross-sectional view (top image) and a two-dimensional cross-sectional view (bottom image) of implant 700C. Implant 700C may be similar to implant 700A and may include one, more, or all of the features of implant 700A. However, in implant 700C, the undulating portion of channel 103 is sinusoidal rather than zigzag.

[0119] In a sinusoidal sidewall portion, the tangent along the first plurality of consecutive strands 745 can be a varying tangent (e.g., gradually changing, e.g., gradually decreasing), and the tangent along the second plurality of consecutive strands 746 can also be a varying tangent (e.g., gradually changing, e.g., gradually increasing). In a zigzag sidewall portion, the tangent along the first plurality of consecutive strands 745 can be a constant tangent (e.g., a fixed tangent value, e.g., a positive tangent), and the tangent along the second plurality of consecutive strands 746 can also be a constant tangent (e.g., a fixed tangent value, e.g., a negative tangent).

[0120] FIG. 7D shows an example of a further implant 700D. FIG. 7D includes a three-dimensional perspective cross-section (top image) and a two-dimensional cross-section (bottom image) of implant 700D. Implant 700D may be similar to implant 700C and may include one, more, or all of the features of implant 700C. However, in implant 700D, second sidewall portion 134 may be a mirror image of first and second sidewall portions 134 about longitudinal axis 742D.

[0121] Figure 7E shows an example of a further implant 700E. Figure 7E includes a three-dimensional perspective cross-section (top image) and a two-dimensional cross-section (bottom image) of implant 700E. Implant 700E may be similar to implants 700A-700D and may include one, more, or all of the features of implants 700A-700D.

[0122] As shown for implant 700E, the contoured portion may include a zigzag portion, and the angle θ of the contoured portion (e.g., θt or θp) may be different (or vary) from one another within the contoured portion of sidewall 134. Varying the angle θ may vary the softness of the implant. For example, portions of the implant with a smaller θ may be softer than portions of the implant with a larger θ. Additionally, or if desired, characteristics such as peak-to-trough height hpt, peak-to-peak width wpp, and / or trough-to-trough width wtt may vary (be different from one another) within the contoured portion of sidewall 134.

[0123] It will be appreciated that the features of Figures 7A-7G may be combined with one another to form an implant having a desired softness and resilience.

[0124] A (or each) contoured sidewall may include at least one of a zigzag portion and a sinusoidal portion. If desired, the zigzag (or sinusoidal) portion may extend the entire length of the channel 103 (or may include the entire length of the channel 103). Alternatively, the zigzag (or sinusoidal) portion may extend over (or include) a selected portion (e.g., a percentage, a subportion, or a segment) of the entire length of the channel 103. In some examples, one or more or all of these parameters (angles θt, θp, hpt, wpp, wtt) may be constant (e.g., the same) throughout (or within) the contoured portion. In other examples, these parameters may vary throughout (or within) the contoured portion. In some examples, the contoured portion may include the entire (e.g., full) length of the sidewall 134. In some examples, the contoured portion may comprise 10%-90% (or, for example, 20%-80%, or, for example, 30%-70%) of the entire sidewall 134. For example, the sidewall may include contoured portions and straight portions. In some examples, the sidewall 134 may include any number and / or combination of zigzag portions, sinusoidal portions, and straight portions.

[0125] The sidewalls 134 of the channel 103 (e.g., the sidewalls surrounding the channel 103) may be similar (the same, or e.g., identical) to one another. Alternatively, or if desired, they may be dependent on one another (e.g., mirror images of one another). Alternatively, or if desired, they may be different from one another. In some examples, all of the sidewalls of the implant may be sinusoidal sidewalls. In other examples, all of the sidewalls of the implant may be zigzag sidewalls. In some examples, the sidewalls of the implant may be a mixture of zigzag and sinusoidal sidewalls.

[0126] Figure 7F shows an example of a further implant 700F. Figure 7F includes a three-dimensional perspective cross-sectional view (top image) and a two-dimensional cross-sectional view (bottom image) of implant 700F. Implant 700F may be similar to implants 700A-700E and may include one, more, or all of the features of the implants.

[0127] While Figures 7A-7E show channels that run parallel to the z-direction, as shown in Figure 7F, implant 700F may include angled zigzag (sinusoidal) channels.

[0128] In an inclined channel, the acute inclination angle k between the longitudinal axis 742E and a reference axis representing the first outer surface area (e.g., the x-axis or y-axis) may be less than 90°, or, for example, less than 60°.

[0129] Figure 7G shows an example of a further implant 700G. Figure 7G includes a three-dimensional perspective cross-sectional view (top image) and a two-dimensional cross-sectional view (bottom image) of implant 700G. Implant 700G may be similar to implants 700A-700F and may include one, more, or all of the features of implants 700A-700F.

[0130] 7G shows a sidewall having fractal zigzags (e.g., zigzags within zigzags). In other words, the first plurality of continuous strands 745 may include zigzags instead of forming a smooth surface. Additionally, or optionally, the second plurality of continuous strands 746 may include zigzags instead of forming a smooth surface or line.

[0131] 7A-7G, the peak-to-trough height hpt, which is the vertical height between a peak and an adjacent trough, and the peak-to-peak width wpp (and / or trough-to-trough width wtt) between immediately successive peaks may be 1%-99% (or, for example, 1%-50%, or, for example, 1%-20%, or, for example, 1%-5%) of the maximum dimension of the implant. The maximum dimension of the implant may be the maximum dimension of the implant in the x-, y-, or z-direction.

[0132] It will be understood that the features described with respect to the various embodiments of Figures 1A to 7G may be combined with one another. The present invention is further characterized by the following:

[0133] Item 1: A three-dimensional implant for insertion into a patient. The implant includes a plurality of strands forming a three-dimensional structure. The three-dimensional structure includes a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. The sidewalls include a plurality of strand segments and a plurality of gaps, alternating such that a gap is formed between adjacent strand segments of the sidewalls. The plurality of gaps are reversibly expandable gaps.

[0134] Item 2: The implant according to item 1, wherein the reversibly expandable gap is expandable to greater than 110% of the baseline gap height.

[0135] Item 3: The implant of items 1 or 2, wherein the reversibly expandable gap is expandable to a baseline gap height, the baseline gap height being the minimum height of the gap when the implant is at rest.

[0136] Item 4: The implant of any one of items 1 to 3, wherein the reversibly expandable gap is expandable relative to a baseline gap height.

[0137] Item 5: The implant of any one of items 1 to 4, wherein the reversibly expandable gap is expandable relative to a baseline gap height, and the baseline gap height of the gap is between 0.1 mm and 2 mm.

[0138] Item 6: An implant according to any one of items 1 to 5, wherein the reversibly expandable gap is expandable relative to a baseline gap height, and the baseline gap length is at least two times greater than the baseline gap height.

[0139] Item 7: The implant of any one of items 1 to 6, wherein the plurality of strands are configured such that the gaps of the plurality of gaps are reversibly expandable when the implant is at rest and when the implant is compressed.

[0140] Item 8: The implant according to any one of Items 1 to 7, wherein the implant is reversibly compressible to less than 80% of its rest volume, wherein the rest volume refers to the volume of the implant when the implant is released from tensile and compressive forces.

[0141] Item 9: An implant according to any one of items 1 to 8, wherein the implant is configured to receive an elongated object within the bulk of the three-dimensional structure.

[0142] Item 10: The implant described in Item 9, wherein the elongated object has a diameter greater than the baseline gap height of the reversibly expandable gap, and the elongated object has a length greater than twice the width of the hollow channel.

[0143] Item 11: The implant of any one of items 1-10, wherein the plurality of strands are configured such that an object received by the gap increases the height of the gap and an object removed from the gap decreases the height of the gap, wherein the object has a diameter greater than the baseline gap height of the gap.

[0144] Item 12: The implant according to item 11, wherein the gap height is the smallest dimension of the gap measured at the midpoint of the gap.

[0145] Item 13: The implant of items 11 or 12, wherein the gap height increases to more than 110% of the baseline gap height with the object received by the gap, and the gap height decreases to less than 105% of the baseline gap height with the object removed from the gap.

[0146] Item 14: The implant according to any one of items 11 to 13, wherein the plurality of strands are arranged such that the reversibly expandable gaps of at least two different sidewalls are simultaneously expandable by an object simultaneously received by the gaps of the at least two different sidewalls.

[0147] Item 15: An implant according to any one of items 11 to 14, wherein the plurality of strands are arranged such that the reversibly expandable gaps of at least two consecutive hollow channels are simultaneously expandable by receiving an object through the gaps of the at least two consecutive hollow channels simultaneously.

[0148] Item 16: The implant according to any one of items 9 to 15, wherein the object is a needle.

[0149] Item 17: The implant according to item 16, wherein the needle has a diameter of at least 1 mm and a length of at least 2 cm.

[0150] Item 18: The implant described in Item 1, wherein each hollow channel extends along a longitudinal axis of the hollow channel and the plurality of strand segments are arranged consecutively in a direction between a first end of the longitudinal axis and a second end of the longitudinal axis.

[0151] Item 19: The implant according to any one of items 1 to 18, wherein the plurality of continuous strand segments forming the sidewalls of the hollow channel are substantially parallel to one another.

[0152] Item 20: The implant according to any one of items 1 to 19, wherein each hollow channel comprises at least a first sidewall including a first plurality of contiguous strand segments and a first plurality of reversibly expandable gaps, and a second sidewall including a second plurality of contiguous strand segments and a second plurality of reversibly expandable gaps, the second sidewall being continuous with the first sidewall, and the strand segments of the first plurality of contiguous strand segments and the strand segments of the second plurality of contiguous strand segments being alternately arranged in a direction between a first end of the longitudinal axis and a second end of the longitudinal axis.

[0153] Item 21: The implant according to any one of items 1 to 20, wherein the channels of the plurality of hollow channels are arranged adjacent to each other and adjacent channels share a common sidewall.

[0154] Item 22: The implant according to any one of Items 1 to 21, wherein the multiple sidewalls of the hollow channel are arranged so that the cross-sectional shape of the hollow channel has any one shape selected from the group consisting of polygon, triangle, diamond, rhombus, square, ellipse, sine wave, and hexagon.

[0155] Item 23: The implant according to any one of items 1 to 22, wherein 80% or more of all sidewalls of the plurality of sidewalls include a reversibly expandable gap.

[0156] Item 24: The implant according to any one of items 1 to 23, wherein 50% or more of all gaps in the plurality of sidewalls are reversibly expandable gaps.

[0157] Item 25: The implant of any one of items 1 to 24, wherein a strand break point in the plurality of strands is defined by a strain greater than 30% and a corresponding stress less than 250 MPa.

[0158] Item 26: The implant according to any one of items 1 to 25, wherein the plurality of strands are made of a polymer material.

[0159] Item 27: The implant according to item 26, wherein the flexible polymer material comprises at least one material from the group of flexible polymer materials consisting of polycaprolactone, poly(1,3-trimethylene carbonate), polylactide, polyglycolide, poly(ester amide), poly(ethylene glycol) / poly(butylene terephthalate), poly(glycerol sebacate), poly(1,8-octanediol-co-citric acid), poly(1,10-decanediol-co-D,L-lactic acid), poly(diol citrate), poly(glycolide-co-caprolactone), poly(1,3-trimethylene carbonate-co-lactide), poly(1,3-trimethylene carbonate-co-caprolactone) and copolymers of at least two of these materials.

[0160] Item 28: The implant according to any one of items 1 to 27, wherein the strand thickness of the plurality of strands is between 0.05 mm and 2 mm.

[0161] Item 29: The implant according to any one of items 1 to 28, wherein the plurality of strands constitute a material volume, and the material volume is 5% to 50% of the total implant volume of the implant.

[0162] Item 30: The implant of item 29, wherein the plurality of sidewalls constitutes 80% or more of the material volume of the three-dimensional structure.

[0163] Item 31: The implant according to any one of items 1 to 30, wherein the implant comprises multiple layers of strands arranged on top of each other, the multiple layers of strands forming an array of unit cells of a three-dimensional structure.

[0164] Item 32: The implant of any one of items 1 to 31, further comprising one or more contouring strands disposed on an outer surface region of the implant, the plurality of contouring strands being arranged such that a plurality of reversibly expandable contouring gaps are formed between adjacent strand segments of the plurality of contouring strands.

[0165] Item 33: An implant according to any one of items 1 to 32 for use in guiding a needle through the implant for an implant surgery.

[0166] Item 34: A method for forming an implant. The method includes forming a plurality of strands to form a three-dimensional structure. The three-dimensional structure includes a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. The sidewalls include a plurality of gaps and a plurality of consecutive strand segments of the plurality of strands. The strand segments and the gaps are alternately arranged such that gaps are formed between adjacent strand segments of the sidewalls. The gaps are reversibly expandable.

[0167] Item 35: The method of item 34, wherein forming the plurality of strands comprises sequentially printing a plurality of layers, the layers comprising a lattice array of two-dimensional unit cells, the plurality of layers being arranged such that the aligned unit cells of successive layers of the plurality of layers form hollow channels of the plurality of channels.

[0168] Item 36: The method of Item 34 or 35, further comprising: determining at least one of the number of hollow channels of the three-dimensional structure to be formed, the number of layers of the three-dimensional structure to be formed, and the dimensions of a unit cell; and forming a plurality of strands so as to form a three-dimensional structure including a reversibly expandable gap, wherein the three-dimensional structure includes the determined number of hollow channels, the determined number of layers, and the determined dimensions of a unit cell.

[0169] Item 37: The method of any one of items 34 to 36, wherein the reversibly expandable gap is expandable to greater than 110% of the baseline gap height.

[0170] Item 38: The method of any one of items 34 to 37, wherein the reversibly expandable gap is expandable to a baseline gap height, the baseline gap height being the minimum height of the gap when the implant is at rest.

[0171] Item 39: A three-dimensional soft tissue implant for insertion into a patient. The implant includes a plurality of strands forming a three-dimensional structure including a plurality of hollow channels. Each hollow channel includes a plurality of sidewalls. Each sidewall includes a plurality of alternating strand segments and a plurality of gaps. At least one sidewall of the hollow channel is a contoured sidewall.

[0172] Item 40: The implant of item 39, wherein the contoured sidewall includes at least one of a zigzag portion and a sinusoidal portion.

[0173] Item 41: The implant of item 39 or 40, wherein each hollow channel comprises a first contoured sidewall and a second contoured sidewall.

[0174] Item 42: A method for tissue reconstruction or tissue augmentation, comprising implanting into the body of a subject an implant defined in any one of Items 1 to 33 or any one of Items 39 to 41, which has been produced by the method defined in any one of Items 34 to 38.

[0175] Item 43: The method of item 42, including reconstruction of a body part.

[0176] Item 44: The method of Item 43, wherein the body part is selected from the group consisting of the breast, chest, buttocks, calf, and part of the face.

[0177] Item 45: The method according to Item 44, wherein the part of the face is the cheek.

[0178] Item 46: The method of Item 44, wherein the subject has pectus excavatum.

[0179] Item 47: The method according to any one of items 42 to 44, including breast reconstruction.

[0180] Item 48: The method of item 47, wherein the breast reconstruction is performed after a lumpectomy or mastectomy.

[0181] Having thus described the embodiments of the present invention in detail, it will be understood that the invention as defined by the appended claims is capable of many obvious variations without departing from its spirit or scope and therefore should not be limited to the specific details set forth in the above description.

Claims

1. A three-dimensional implant (100, 200, 300) for soft tissue reconstruction or soft tissue augmentation for insertion into a patient, comprising: The implant comprises a plurality of strands (101) forming a three-dimensional structure (102); The three-dimensional structure (102) comprises a plurality of hollow channels (103), Each of the hollow channels (103) comprises a plurality of sidewalls (104); the sidewall (104) comprises a plurality of strand segments (105) and a plurality of gaps (106) arranged alternately such that a gap (106) is formed between adjacent strand segments (105) in the sidewall; The gap is composed of a gap length (gl) and a static gap height (gh), the plurality of gaps (106) are reversibly expandable gaps; the height of the reversibly expandable gap is increased by an object (155) received by the gap causing a deflection (δ) in each of the adjacent strand segments; the height of the reversibly expandable gap decreases as the object is removed from the gap; the plurality of strands (101) are formed from a material having a yield strength (σ) and a modulus of elasticity (E); Each strand (101) has a length and a cross-sectional diameter; the ratio of the radius (R) of the strand segment (105) to the square of the gap length (gl) of the reversibly expandable gap is based on the yield strength (σyield) of the material, the elastic modulus (E) of the material, and the deflection capacity (δ) of the strand segment (105) of the gap (106); the deflection capacity (δ) is the deflection of the adjacent strand segments caused by the insertion of the object into the gap; An implant characterized in that the ratio of the radius (R) of the strand segment (105) to the square of the gap length (gl) of the reversibly expandable gap (106) is expressed by the following formula, where δ represents the bending capacity of the strand segment of the gap: [Equation 1]

2. 10. The implant of claim 1, An implant characterized in that the ratio of the radius (R) of the strand segment (105) to the square of the gap length (gl) of the reversibly expandable gap (106) is proportional to the ratio between the yield strength (σyield) of the material and the product of the elastic modulus (E) and the deflection capacity (δ) of the strand segment (105) of the gap (106).

3. 3. The implant according to claim 1 or 2, The implant is characterized in that the deflection capacity (δ) of the strand segments of the reversibly expandable gap (106) is between 0.05 and 0.75 times the rest gap height (gh) of the gap.

4. 4. The implant according to claim 1, The reversibly expandable gap (106) is expandable relative to the resting gap height; The rest gap height is the minimum or minimum height between the adjacent strand segments when the implant is at rest.

5. 5. The implant according to claim 1, the channels of the plurality of hollow channels (103) are arranged adjacent to each other; An implant characterized in that adjacent channels share a common sidewall.

6. 6. The implant according to claim 1, An implant, wherein 80% or more of all of said sidewalls (104) of said plurality of sidewalls include said reversibly expandable gap (106).

7. 7. The implant according to claim 1, An implant, wherein 50% or more of all gaps in said plurality of sidewalls (104) are reversibly expandable gaps (106).

8. 8. The implant according to claim 1, the material for forming the plurality of strands has a break point on a stress-strain diagram; The implant has a strain at break greater than 30% and a stress at break less than 250 MPa.

9. 9. The implant according to any one of claims 1 to 8, The plurality of strands (101) comprises a volume of material; The implant, wherein the material volume is 5% to 50% of the total implant volume of the implant.

10. 10. The implant according to any one of claims 1 to 9, further comprising one or more contouring strands (319) disposed on an outer surface region of said implant; The implant is characterized in that the plurality of contouring strands (319) are arranged such that a plurality of reversibly expandable contouring gaps are formed between adjacent strand segments of the plurality of contouring strands.

11. 11. The implant according to any one of claims 1 to 10, The implant, wherein the plurality of hollow channels (103) includes at least one of sinusoidal channels and zigzag channels.

12. The implant according to any one of claims 1 to 11, The implant is a breast implant.

13. 13. The implant according to any one of claims 1 to 12, An implant characterized in that it is used to guide a needle through said implant for implant surgery.

14. 1. A method for forming a three-dimensional soft tissue implant, comprising: The method includes forming (620) a plurality of strands to form a three-dimensional structure; the plurality of strands are formed from a material having a yield strength (σ) and a modulus of elasticity (E); the three-dimensional structure includes a plurality of hollow channels; Each hollow channel comprises a plurality of sidewalls; the sidewall includes a plurality of gaps and a plurality of consecutive strand segments of the plurality of strands; the plurality of strand segments and the plurality of gaps are alternately arranged such that a gap is formed between adjacent strand segments in the sidewall; The gap is composed of a gap length (gl) and a static gap height (gh), the plurality of gaps are reversibly expandable gaps; the height of the reversibly expandable gap increases with an object received by the gap causing a deflection (δ) in each of the adjacent strand segments; the height of the reversibly expandable gap decreases as the object is removed from the gap; Each strand (101) has a length and a cross-sectional diameter; the diameters of the strands are selected such that a radius (R) of the strands and a gap length (gl) of the reversibly expandable gap are based on a yield strength (σ), the elastic modulus (E) of the material, and a deflection capacity δ of the adjacent strand segments forming the reversibly expandable gap; 10. A method for forming a three-dimensional soft tissue implant, wherein the deflection capacity (δ) is the deflection of the adjacent strand segments caused by the insertion of the object into the gap.

15. 15. The method for forming a three-dimensional soft tissue implant according to claim 14, determining the deflection capacity (δ) of the reversibly expandable gap based on an object received by the reversibly expandable gap; determining material properties of the plurality of strands to be formed, including the yield strength (σ) and Young's modulus (E) of the material; determining a radius (R) and gap length (gl) for each strand segment of the plurality of strand segments to be formed; 3. A method for forming a three-dimensional soft tissue implant, further comprising:

16. The method for forming a three-dimensional soft tissue implant according to claim 14 or 15, A method for forming a three-dimensional soft tissue implant, wherein the three-dimensional soft tissue implant is a breast implant.

Images