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CA-3091515-C - EXPANDABLE ABSORBABLE IMPLANTS FOR BREAST RECONSTRUCTION AND AUGMENTATION

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Abstract

Expandable absorbable implants have been developed that are suitable for breast reconstruction following mastectomy. The implants can be implanted in the vicinity of a tissue expander, for example, by suturing to the detached edge of the pectoralis major muscle to function as a pectoralis extender, and used to form a sling for a tissue expander. The implants, which permit tissue-ingrowth and slowly degrade, can be expanded in the breast using a tissue expander in order to form a pocket for a permanent breast implant. After expansion, the tissue expander can be removed and replaced with a permanent breast implant. The expandable implants help reduce patient discomfort resulting from tissue expansion, and avoid the need to use allografts or xenografts to create the pocket for the tissue expander. The expandable absorbable implant preferably comprises poly-4-hydroxybutyrate or copolymer thereof.

Inventors

  • Skander Limem
  • Bhavin Shah
  • Said Rizk
  • Matthew Dubois
  • Simon F. Williams

Assignees

  • TEPHA, INC.

Dates

Publication Date
20260505
Application Date
20190219
Priority Date
20180220

Claims (20)

  1. We claim: 1. An expandable absorbable polymeric breast implant, wherein the implant comprises fibers, wherein the fibers are configured to be more oriented upon expansion of the implant, wherein the implant is configured to be expanded by 31% to 100% of its original dimension in one or more directions, and wherein a tensile strength or burst strength of the breast implant initially increases upon expansion of the breast implant.
  2. 2. The implant of claim 1, wherein one or more dimensions of the implant are configured to be expanded in vivo by 31% to 100% using a tissue expander.
  3. 3. The implant of claim 2, wherein one or more dimensions of the implant are configured to be expanded in vivo by 35% to 75% using the tissue expander.
  4. 4. The implant of claim 3, wherein one or more dimensions of the implant are configured to be expanded in vivo by 45% to 65% using the tissue expander.
  5. 5. The implant of any one of claims 2 to 4, wherein the implant is configured to be expanded within 4 months of implantation.
  6. 6. The implant of any one of claims 2 to 4, wherein the implant is configured to be expanded within 3 months of implantation.
  7. 7. The implant of any one of claims 2 to 4, wherein the implant is configured to be expanded within 2 months of implantation.
  8. 8. The implant of any one of claims 2 to 4, wherein the implant is configured to be expanded in the breast over a period ranging from the time of implantation to 6 months post implantation using the tissue expander.
  9. 9. The implant of any one of claims 2 to 4, wherein the implant is configured to be expanded in the breast over a period ranging from the time of implantation from 10 days post implantation to 8 weeks post-implantation, using the tissue expander.
  10. 10. The implant of claim 8 or 9, wherein the implant is expanded by filling the tissue expander with 1 cc to 150 cc of fluid or gas on one or more occasions.
  11. 11. The implant of claim 10, wherein the implant is expanded by filling the tissue expander with 50 cc to 120 cc of fluid on two to five occasions. 44
  12. 12. The implant of claim 10, wherein the implant is expanded by filling the tissue expander with 10 cc to 50 cc of gas each day until the desired expansion is obtained.
  13. 13. The implant of claim 12, wherein the implant is expanded by filling the tissue expander with 30 cc of gas, each day until the desired expansion is obtained.
  14. 14. The implant of any one of claims 1 to 13, wherein a thickness of the implant is between 100 µm and 1 cm.
  15. 15. The implant of any one of claims 1 to 13, wherein a thickness of the implant is between 500 µm and 5 mm.
  16. 16. The implant of any one of claims 1 to 13, wherein a thickness of the implant is between 1 mm and 3 mm.
  17. 17. The implant of any one of claims 1 to 16, wherein the dimensions of the implant are between 5 cm x 15 cm and 15 cm x 30 cm.
  18. 18. The implant of any one of claims 1-17, wherein the implant comprises one or more of the following: (i) a lattice, or (ii) a mesh.
  19. 19. fibers.
  20. 20. The implant of claim 18, wherein the lattice comprises struts, and the mesh comprises The implant of any one of claims 1-19, wherein the implant has average pore diameters that are: (i) greater than 75 µm, or (ii) less than 5 mm, or (iii) greater than 75 µm and less than 5 mm.

Description

EXPANDABLEABSORBABLEIMPLANTSFORBREAST RECONSTRUCTION AND AUGMENTATION CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Application No. 62/632,498, filed on February 20, 2018. FIELD OF THE INVENTION The present invention generally relates to the field of surgery, and more particularly, the invention relates to expandable absorbable implants that can be used in conjunction with tissue expanders in breast reconstruction and breast augmentation. The expandable implant can be implanted in the vicinity of a tissue expander in the breast, expanded upon inflation of the tissue expander, and allows tissue in-growth into the implant as the implant degrades. After expansion, the tissue expander may be removed from the breast, and replaced with a permanent breast implant. The implants are suitable for use in patients that have elected breast reconstruction following a mastectomy. BACKGROUND OF THE INVENTION Breast reconstruction following mastectomy has become an integral and important part of breast cancer treatment with the surgery providing the patient with both aesthetic and psychosocial benefits. Nearly 65% of US breast reconstruction procedures now use a tissue expander (TE) which is temporarily implanted in the breast to create a pocket for a permanent breast implant in the first step of the procedure. The TE is then removed and replaced with a permanent breast implant in a second step. In the first step of the reconstruction procedure, the pectoralis major muscle and serratus anterior muscle are released, elevated, and used to cover the TE. The TE may then be expanded by injecting liquid or gas into the device. Expansion is normally started 10 to 14 days after implantation of the TE, and repeated every 1-4 weeks. The TE is often filled with up to 50% of the final volume intraoperatively. Typically, 60-120 cm3 of saline is injected into the TE each time thereafter, and expansion is usually completed within 2 months. 1 Date Rer;ue/Date Received 2023-01-10 A more recent modification of the TE breast reconstruction procedure is to use an acellular dermal matrix (ADM) to help cover the TE (Bertozzi, N. Ann Med Surg. 21:34-44 (2017)). In a typical procedure, the pectoralis major muscle is mobilized, and the ADM is attached to the edge of the muscle in order to create a sling and submuscular pocket for the TE. The use of ADM eliminates the need to release and elevate the serratus anterior muscle, the pectoralis minor muscle, and the rectus abdominis fascia, and consequently, reduces postoperative pain. Other advantages of using an ADM include (i) creation of a larger pocket size, (ii) the ability to use a larger intraoperative fill volume for the TE and more rapid expansion, (iii) reduced incidence of capsular contracture formation, and (iv) improvements in aesthetic results, including a more natural shape and better definition of the lower pole. While the use of ADM materials has many advantages, there are a number of significant disadvantages to their use. First, ADM resists stretching which puts undue stress on the pectoralis major muscle, and can be uncomfortable for the patient. Second, ADM tends to be very expensive. And, third, ADM is an animal or human derived implant with an associated risk of disease transmission. A few researchers have sought alternatives to using an ADM as a pectoralis extender. US Patent Application No. 20120022646 to Mortarino and Altman discloses a method of using a silk scaffold device in two-stage breast reconstruction. The scaffolds, now known as SERI® Surgical Scaffold, however, were designed to preserve mechanical stability, for example, using a "node-lock" design, and therefore were not designed to expand when sutured in place, and the TE inflated. As reported by Jewell et al. Ann. N. Y. Acad Sci. 1358:44-55 (2015), the silk scaffolds have only a 7% elongation to break in the transverse direction and approximately a 4% elongation to break in the vertical direction which means that these scaffolds will resist expansion as the TE is expanded. US Patent No. 8,858,629 to Moses discloses systems and methods for mastopexy (breast lift procedures), including TephaFLEX™ mesh, made 2 Date Rer;ue/Date Received 2023-01-10 from Tepha's P4HB™ polymer (poly-4-hydroxybutyrate polymer), but does not disclose an expandable mesh made from P4HB suitable for use with a TE in breast reconstruction. Instead, a highly oriented P4HB mesh is disclosed that is designed to support the breast in a breast lift procedure, and not stretch after implantation (since stretching would result in ptosis). US Patent No. 9,532,867 to Felix discloses absorbable implants for breast surgery that confer shape to the breast, and that cannot stretch more than 30% of their original length. The implants are designed to support the breast following surgery to prevent ptosis, and are not designed for use with a TE for breast reconstruction. US Patent No. 9,566,370 to Mathisen di