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EP-4021345-B1 - SOFT TISSUE RECOSTRUCTION IMPLANTS AND FORMING METHOD THEREFOR

EP4021345B1EP 4021345 B1EP4021345 B1EP 4021345B1EP-4021345-B1

Inventors

  • Chhaya, Mohit Prashant
  • DESAI, Arpita
  • KHANI, Navid
  • LUCAROTTI, Sara

Dates

Publication Date
20260513
Application Date
20200904

Claims (15)

  1. A soft tissue reconstruction implant (100, 200, 300, 400, 500) for insertion into a patient, the implant comprising: a plurality of repeated unit cells (102) connected to each other to form a three-dimensional lattice structure (101), the unit cell (102) being a basic unit of the three-dimensional lattice structure, the three-dimensional lattice structure comprising a resting volume of the implant, wherein the plurality of unit cells (102) are arranged to form a porous network of the three-dimensional lattice structure, and wherein the three-dimensional lattice structure (101) is a reversibly compressible three-dimensional lattice structure, wherein the bulk porosity of the three-dimensional lattice structure (101) of the implant is at least 50 %; a plurality of surface filler portions arranged to form a plurality of surface filler columns (125) at the outer surface region (106); and a plurality of open columns at the outer surface region that are free from surface filler portions.
  2. The implant of claim 1, wherein individual unit cells (102) of the plurality of unit cells are reversibly compressible spring-like unit cells, wherein the three-dimensional lattice structure is compressible to at least 80% of its resting volume.
  3. The implant of claims 1 or 2, comprising layers of the unit cells stacked successively on top of each other, wherein edge regions of the layers of the three-dimensional lattice structure form an outer surface region of the implant, wherein the outer surface region represents a geometry of the patient's body part to be constructed by the implant.
  4. The implant of any one of claims 1 to 3, wherein the average pore size of openings at a first outer surface region (105) of the three-dimensional lattice structure (101) is at least 25 % larger than an average pore size of openings at a second outer surface region (106) of the three-dimensional lattice structure (101).
  5. The implant of any one of claims 1 to 4, wherein the three-dimensional lattice structure (101) comprises a first outer surface region (105) of the implant comprising a first surface curvature; and a second outer surface region (106) of the implant comprising a second surface curvature, wherein the second outer surface region (106) of the implant is contiguous to the first outer surface region (105) of the implant at a perimeter (107) of the first outer surface region (105), and wherein a geometry of the second outer surface region (106) represents a geometry of a breast region, a malar region, a gluteal region, or genital region to be constructed by the implant.
  6. The implant of claim 5, wherein the second outer surface region (106) comprises an upper pole portion (109) comprising a geometry of an upper portion of the breast to be constructed by the implant, and a lower pole portion (111) comprising a geometry of a lower portion of the breast to be constructed by the implant, wherein the upper pole portion (109) and lower pole portion (111) are coincident at an apex region (112) of the second outer surface region (106) of the three-dimensional lattice structure (101).
  7. The implant of claim 6, wherein a pore size of openings at a second outer surface region (106) of the implant increases from 0.5 mm at an upper pole interface region (114) to 2 mm or to 5 mm at an apex region of the second outer surface region, and from 10 mm, or 8 mm, or 6 mm at a lower pole interface region (115) up to 0.5 mm towards an apex region (112).
  8. The implant of claim 6, wherein a pore size of openings at a second outer surface region (106) of the implant increases from 0.5 mm at an upper pole interface region (114) to 2 mm or to 5 mm at an apex region of the second outer surface region, and from 0.5 mm at a lower pole interface region (115) up to 6 mm, or up to 8 mm, or up to 10 mm towards an apex region (112).
  9. The implant of any one of claims 4 to 8, wherein the surface porosity of the second outer surface region is less than the bulk porosity of the three-dimensional lattice structure of the implant.
  10. The implant of any one of claims 1 to 9, wherein the material density of the implant lies between 0.1 g/cm 3 and 2 g/cm 3 .
  11. The implant of any one of claims 1 to 10, wherein the three-dimensional lattice structure (101) comprises a first outer surface region (105) comprising a first layer (126) of an arrangement of layers (126), wherein each layer (126) of the arrangement of layers comprises a lattice arrangement comprising a plurality of two-dimensional unit cells (102), wherein two-dimensional unit cells of successive layers of the arrangement of layers form a plurality of hollow channels (118) extending between the first outer surface region (105) and a second outer surface region (106) of the three-dimensional lattice structure.
  12. The implant of any one of claims 1 to 11, comprising a first group of contouring lines (119) of a plurality of lines forming full contours around a perimeter of a first outer surface region of the implant, and a second group of contouring lines (121) of the plurality of lines, wherein each contouring line of the second group of contouring lines (121) forms a semi-contour around a second outer surface region of the implant, wherein the second group of contouring lines (121) are arranged successively with respect to each other between the first outer surface region (105) and an apex region (112) of the second outer surface region (106) of the implant.
  13. The implant of any one of claims 1 to 12, wherein a surface filler portion (122) comprises one or more filler lines (124) configured to at least partially fill an opening at an outer surface region of the three-dimensional lattice structure.
  14. The implant of claim 1 to 13, wherein the c-value representing a softness of the implant lies between 20 N and 200 N, wherein the c-value is expressed by the formula: C = F 20 % − F 10 % ε 20 % − ε 10 % , wherein F 20 % is the force value, in N, at a compression of 20 %, wherein F 10 % is the force value, in N, at a compression of 10 %, wherein ε 10 % is the strain value at a compression of 10 %, and wherein ε 20 % is the strain value at a compression of 20 %.
  15. A method (800) for forming a soft tissue reconstruction implant, the method comprising: sequentially printing layers (830) to form a three-dimensionally (3D) printed lattice structure comprising repeated unit cells, the unit cell being a basic unit of the three-dimensional lattice structure, the 3D printed lattice structure defining a resting volume of the implant to be formed, wherein each printed layer comprises a lattice arrangement of two-dimensional unit cells, wherein the three-dimensionally printed lattice structure has a bulk porosity of at least 50 % such that the three-dimensional printed lattice structure is reversibly compressible, wherein a plurality of surface filler portions are arranged to form a plurality of surface filler columns at the outer surface region; and wherein a plurality of open columns at the outer surface region are free from surface filler portions.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the right of priority of European patent application 19195332.2 filed with the European Patent Office on 4 September 2019. FIELD OF THE INVENTION The embodiments described herein relate to the field implants, and in particular to implants suitable for soft tissue reconstruction to be inserted into a patient, and a method for forming an implant. The use of the implant for tissue reconstruction and/or tissue augmentation is described too. BACKGROUND OF THE INVENTION Breast augmentation and reconstruction mammaplasty have been in practice for decades and are highly prevalent surgeries performed worldwide. While overall patient satisfaction is high, common long-term effects include breast tissue atrophy, accelerated ptosis (e.g. drooping) and inframammary fold breakdown. Increasing evidence attributes these events to the durative loading and compressive forces introduced by breast implants. For example, mechanical challenges exceeding the elastic capacity of the breast tissue components eventually lead to irreversible tissue stretching. Traditional silicone implants may be filled with incompressible fluids, and may introduce a heavy load which causes tissue stretching. Moreover, over time silicone implants may burst causing health issues, and may lead to additional surgeries. Some implants may include space-occupying structures which may be filled with fluid. For example, International patent application WO 2016/038083 and Chhaya et al. Transformation of Breast Reconstruction via Additive Biomanufacturing. Sci. Rep. 6, 28030; doi: 10.1038/srep28030 (2016) discloses an implant that has a three-dimensional scaffold structure having voids, all of which are filled with space-occupying structures. The space-occupying structures are removably attached to the three-dimensional scaffold structure and are configured to prevent invasion of tissue and/or of individual cells. After implantation of the implant, e.g. 6-8 weeks after implantation of the implant) the space-occupying structure are removed in a second surgery from the residual parts of the implant and the site of implantation. Document WO2018130949 discloses an additive manufacturing method for producing reversibly compressible highly porous 3D scaffolds for medical implants. WO2017050837 describes a three-dimensional degradable medical implant for regeneration of soft tissue. CN109172044 and CN107280810 disclose degradable porous scaffolds comprising a three-dimensional boundary structure and an internal filling structure to be used for breast reconstruction. US2019247180 discloses three-dimensional absorbable implants for breast surgery and related manufacturing methods. CN207590799 describes a three-dimensional mesh-shaped implant for rhinoplasty and related 3D printing manufacturing method. CN107638231 discloses a soft tissue reconstruction implant which is in many aspects similar to the implant of the present invention. The implant comprises a plurality of repeated unit cells connected to each other and arranged to form a porous network of a reversibly compressible three-dimensional lattice structure having an overall porosity of 20 to 80%. SUMMARY The present invention is defined by the appended claims. Various embodiments relate to providing a lightweight implant which decreases the effects of ptosis in a patient and reduces adverse reactions by a patient to an implant. The embodiments described herein relate to an implant for insertion into a patient. The implant comprises a plurality of unit cells arranged to form a three-dimensional lattice structure, the three-dimensional structure comprising a resting volume of the implant. The plurality of unit cells are arranged to form a porous network of the three-dimensional structure, and the three-dimensional structure is a reversibly compressible three-dimensional structure, wherein a bulk porosity of the three-dimensional structure (101) of the implant is at least 50 %. Various embodiments relate to a further implant for insertion into a patient. The implant comprises a porous three-dimensional scaffold structure comprising an arrangement of unit cells, wherein the plurality of unit cells are arranged to form a porous network of the three-dimensional structure, wherein an average pore size of the plurality of unit cells of the three-dimensional structure is at least 0.5 mm. Various embodiments relate to a further implant for insertion into a patient. The implant comprises a three-dimensional porous scaffold structure comprising a plurality of hollow channels extending between a first outer surface region and a second outer surface region of the three-dimensional porous scaffold structure, wherein the porous scaffold structure comprises a surface-degradable polymer material. The first outer surface region is configured to face a chest wall of the patient receiving the implant, wherein a geometry of the second outer surface region represent