111111
`
`1111111111111111111111111111111111111111111111111111111111111
`US007637948B2
`
`c12) United States Patent
`Corbitt, Jr.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,637,948 B2
`Dec. 29, 2009
`
`(54) TISSUE MARKING IMPLANT
`
`(75)
`
`Inventor: John D. Corbitt, Jr., Atlantis, FL (US)
`
`(73) Assignee: SenoRx, Inc., Irvine, CA (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 747 days.
`
`(21) Appl. No.: 11/108,785
`
`(22) Filed:
`
`Apr. 19, 2005
`
`(65)
`
`Prior Publication Data
`
`US 2005/0187624 Al
`
`Aug. 25, 2005
`
`Related U.S. Application Data
`
`(60) Continuation-in-part of application No. 10/627,718,
`filed on Jul. 28, 2003, now Pat. No. 6,881 ,226, which is
`a continuation of application No. 09/828,806, filed on
`Apr. 10, 2001, now Pat. No. 6,638,308, which is a
`division of application No. 09/169,351, filed on Oct. 9,
`1998, now Pat. No. 6,214,045.
`
`(60) Provisional application No. 60/091,306, filed on Jun.
`30, 1998, provisional application No. 60/077,639,
`filed on Mar. 11, 1998, provisional application No.
`60/061,588, filed on Oct. 10, 1997.
`
`(51)
`
`Int. Cl.
`A61F 2112
`(2006.01)
`(52) U.S. Cl. ........................................ 623/8; 623/23.75
`(58) Field of Classification Search . ... ... ... ... .. .. 623/7-8,
`623/23.75; 424/400
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,298,998 A
`4,428,082 A
`4,470,160 A
`4,740,208 A
`4,950,665 A *
`
`1111981 Naficy
`111984 Naficy
`9/1984 Cavon
`4/1988 Cavon
`8/1990 Floyd ...................... 514/222.8
`
`5,120,802 A
`5,522,896 A
`RE35,391 E
`5,626,611 A
`
`6/1992 Mares et al.
`6/1996 Prescott
`12/1996 Braurnan
`5/1997 Liu eta!.
`
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`
`0475 077 A2
`
`3/1992
`
`(Continued)
`
`OTHER PUBLICATIONS
`
`P. Eisolt, "Development of Technologies Aiding Large-Tissue
`Engineering", Biotechnol. Prog., vol. 14, No. 1, pp. 134-140, 1998.
`
`Primary Examiner-Suzette J Gherbi
`(74) Attorney, Agent, or Firm-Edward J. Lynch
`
`(57)
`
`ABSTRACT
`
`A tissue marking implant includes a matrix material and a dye
`marker. The implant, which can be formed entirely ofbiore(cid:173)
`sorbable material such as a collagen foam, is sized and shaped
`to replace excised tissue. The implant supports surrounding
`tissue upon implantation, while allowing for in-growth of
`fibrous tissue to replace the implant. According to various
`alternative embodiments, the implant is elastically compress(cid:173)
`ible, or can be formed from self-expanding foam or sponges,
`and can be implanted through a cannula or by injection, as
`well as by open procedures. The implant can carry therapeutic
`and diagnostic substances. The dye marker leaches from the
`implant such that a surgeon, upon subsequent surgical inter(cid:173)
`vention, visibly recognizes the tissue marked by the dye
`marker.
`
`17 Claims, 1 Drawing Sheet
`
`Focal Exhibit 1003 Page 1
`
`

`

`US 7,637,948 B2
`Page 2
`
`........... 623/1.39
`
`U.S. PATENT DOCUMENTS
`5,628,781 A * 5/1997 Williams et a!.
`10/1998 Knapp eta!.
`5,824,081 A
`5,869,080 A
`2/1999 McGregor
`7/1999 Janzen eta!.
`5,922,024 A
`6,066,325 A
`5/2000 Wallace eta!.
`6,161,034 A
`12/2000 Burbank et a!.
`6,214,045 B1
`4/2001 Corbitt, Jr. eta!.
`6,228,055 B1 * 5/2001 Foerster eta!. .............. 604/116
`6,316,522 B1
`1112001 Loomis eta!.
`6,403,758 B1
`6/2002 Loomis
`10/2003 Corbitt et a!.
`6,638,308 B2
`7,044,957 B2 * 5/2006 Foerster eta!. .............. 606/185
`7,229,417 B2 * 6/2007 Foerster eta!. .............. 600/562
`
`7,297,725 B2 *
`7,534,452 B2
`2002/0022883 A1
`2003/0036803 A1
`2005/0175657 A1 *
`2005/0181007 A1 *
`
`1112007 Winterton eta!. ........... 523/107
`5/2009 Chernomorsky et a!.
`212002 Burg
`2/2003 McGhan
`8/2005 Hunter eta!. ............... 424/422
`8/2005 Hunter eta!. ............... 424/423
`
`FOREIGN PATENT DOCUMENTS
`
`EP
`0475 077 B1
`08-500274
`JP
`09-502371
`JP
`wo 94/16647
`wo
`wo 95/07057
`wo
`* cited by examiner
`
`3/1992
`111996
`3/1997
`8/1994
`3/1995
`
`Focal Exhibit 1003 Page 2
`
`

`

`U.S. Patent
`
`Dec. 29, 2009
`
`US 7,637,948 B2
`
`FIG. 1
`
`6
`
`FIG. 2
`
`10
`
`FIG. 4
`
`FIG. 3
`
`FIG. 6
`
`FIG. 5
`
`Focal Exhibit 1003 Page 3
`
`

`

`US 7,637,948 B2
`
`1
`TISSUE MARKING IMPLANT
`
`This application is a continuation in part of U.S. patent
`application Ser. No. 10/627,718, filed Jul. 28,2003, now U.S.
`Pat. No. 6,881,226, which is a continuation of U.S. patent
`application Ser. No. 09/828,806 filed Apr. 10, 2001, now U.S.
`Pat. No. 6,638,308, which is a division of U.S. patent appli(cid:173)
`cation Ser. No. 09/169,351, filed Oct. 9, 1998, now U.S. Pat.
`No. 6,214,045, which claims the benefit of U.S. Provisional
`Application Ser. No. 60/061,588, filed Oct. 10, 1997, U.S.
`Provisional Application Ser. No. 60/077,639, filed Mar. 11,
`1998, and U.S. Provisional Application Ser. No. 60/091,306,
`filed Jun. 30, 1998, the disclosure of which are incorporated
`herein by reference.
`
`BACKGROUND OF THE INVENTION
`
`The present invention relates to implantable prostheses.
`More particularly, the present invention relates to implantable
`breast prostheses designed to eliminate encapsulation and
`reduce scarring, and to replace tissue removed for purposes of
`biopsy or lumpectomy.
`
`DESCRIPTION OF THE RELATED ART
`
`Breast prostheses are utilized for augmentation mammo(cid:173)
`plasty and in cosmetic surgery. Prostheses are also indicated
`in breast cancer surgery, such as lumpectomies, where a por(cid:173)
`tion of the breast is removed and can leave some disfigure(cid:173)
`ment if not replaced by a similar amount of tissue and/or
`augmentation material.
`Similarly, biopsies can leave small dimples or imperfec- 35
`tions if remedial steps are not taken. About 1 million breast
`biopsies are performed in the United States annually. As a
`result, some 200,000 new breast cancers are diagnosed each
`year.
`Known methods of augmentation mammoplasty utilize 40
`silicone or saline implants. These methods have been com(cid:173)
`plicated post-operatively by encapsulation of the implants,
`which can occur to varying degrees. Encapsulation produces
`a hard area of scar tissue around the implant, resulting in a
`rigid, abnormally-shaped mount beneath the breast tissue or
`pectoralis muscle, depending upon the placement of the
`implant.
`Moreover, the known implant materials may not be indi(cid:173)
`cated for replacement of smaller amounts of tissue, as would 50
`be required to prevent dimpling after biopsies, for example.
`Further, the known implant materials are not amenable to
`resizing. In addition, known implants are not capable ofbeing
`implanted through a cannula or needle, and are not readily
`instilled with medicaments or chemical agents that would be 55
`useful in treating the patient.
`Accordingly, a need exists for implants and methods that
`can be adapted for replacement of small as well as large
`amounts of tissue. A need also exists for implants that can be 60
`delivered through cannulae or needles, as well as being able to
`significantly reduce or eliminate encapsulation, resulting in a
`prolonged, aesthetically pleasing, soft mound below the
`breast tissue or pectoralis muscle. In addition, a need exists
`for implants into which useful substances, such as beneficial 65
`medications, chemical agents, hormonal treatments, stem
`cells, such as adipocytes, cellular precursors and components,
`
`45
`
`2
`and radiation media can be instilled to enhance the treatment
`capabilities of the implant in cancer and other breast pathol(cid:173)
`ogy.
`
`BRIEF SUMMARY OF THE INVENTION
`
`The present invention overcomes deficiency of the prior
`art, such as those noted above, by providing an implant in
`which at least the outer portion of the implant, and as much as
`10 the entire implant, is made of a resorbable material. The
`implant is sized and shaped to reduce excised tissue. Prefer(cid:173)
`ably, the implant provides a support structure in the form of a
`framework or scaffold for the surrounding tissue after
`implantation. The support structure preferably is porous to
`15 permit the in-growth of fibrous replacement tissue. Advanta(cid:173)
`geously, replacement tissue in-growth takes place without
`encapsulation and with reduced scarring.
`According to an embodiment of the invention, excised
`tissue is replaced by installing an implant having at least an
`20 outer shell of resorbable material. The implant is sized and
`shaped to replace the excised tissue. The implant supports
`surrounding tissue while fibrous tissue replaces the resorb(cid:173)
`able portion of the implant.
`In a further development, at least a portion of the implant
`25 can be provided in the form of a compressible or non-com(cid:173)
`pressible sponge or foam, or a self-expanding sponge or
`foam. The sponge or foam provides a porous support matrix
`for surrounding and in-growing tissue. In the form of a com(cid:173)
`pressible, expandable, or self-expanding sponge or foam, the
`30 implant advantageously can be inserted through a cannula or
`a needle, or optionally can be directly inserted. Additionally,
`the implant can be instilled with beneficial materials, such as
`indicated medicaments, therapeutics, or diagnostic agents, as
`well as matrix enhancing additives.
`Other features and advantages of the present invention will
`become apparent from the following description of the inven(cid:173)
`tion which refers to the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a schematic elevation of a breast implant accord(cid:173)
`ing to a preferred embodiment of the present invention.
`FIG. 2 is a schematic sectional view of a breast after
`implantation of the implant of FIG. 1.
`FIG. 3 is a schematic sectional view of a breast after
`implantation of an alternative embodiment of the implant of
`the present invention.
`FIG. 4 is a schematic sectional view of a breast implant
`according to a second alternative embodiment of the present
`invention.
`FIG. 5 is a schematic sectional view of a breast after imple(cid:173)
`mentation of the implant of FIG. 4.
`FIG. 6 is a schematic sectional view of a breast implant and
`a method of insertion according to further alternative embodi(cid:173)
`ments of the present invention, particularly for cases involv(cid:173)
`ing the removal of smaller pieces of tissue such as by biopsy
`and lumpectomy.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`Referring initially to FIGS. 1 and 2, an implant 2 has an
`outer shell 4 made of a biosorbable material woven into a
`mesh. The inner contents of the implant are fluids such as
`saline and autologous blood products.
`Outer shell 4 is made entirely of biosorbable materials,
`such as collagens or polyglycolic acids, for example. Over a
`period of approximately three weeks to six months, the outer
`
`Focal Exhibit 1003 Page 4
`
`

`

`US 7,637,948 B2
`
`4
`3
`shell dissolves, leaving the inner contents 6 present inside the
`distal end of the carmula into the implant site, where the
`resilient implant 20 expands to fill the implant site space.
`breast. Hard encapsulation will not occur because there is not
`The force for advancing the sponge or foam material
`a foreign body contained within the prosthetic space.
`through the cannula can be applied directly to the implant, or
`Referring to FIG. 3, implantation of an alternative embodi(cid:173)
`indirectly using fluids, for example. Advantageously, the
`ment of implant 2 is illustrated in which the outer shell 4
`implant can be used in conjunction with stereotactic biopsy
`includes both biosorbable material, and non-absorbable
`instrumentation, such as theABBI® System, the MIB System
`material, such as monofilament polypropylene fibers. Outer
`by US Surgical, or the Manmwtome® System by Johnson
`shell 4 is provided as a mesh or weave of the mixed material,
`and Johnson.
`surrounding contents 6 as described above. After a resorption
`As a further alternative, the sponge or foam implant of the
`period, contents 6 remain surrounded by a skeletal outer shell 10
`present invention can form all or part of a larger implant, such
`made up of non-absorbable fibers 8.
`as those described above. Accordingly, the tissue supporting
`Advantageously, the proportions and spacing of the two
`sponge or foam or foam matrix will form, for example, all or
`types of materials can be altered to provide the desired prop(cid:173)
`part of the outer shell4 of implant 2. Implantation using open
`erties of containment using a minimal amount of nonabsorb(cid:173)
`15 procedures usually would be indicated when the sponge
`able material. Accordingly, the non-absorbable fibers 8 which
`implant of the present invention is used as all or part of a larger
`remain after the biosorbable materials resorb will act as a
`implant. Accordingly, the sponge or implant would be placed
`scaffolding to allow the prosthesis to hold its shape; however,
`directly into the biopsy or lumpectomy cavity.
`because of the limited amount of foreign material, encapsu(cid:173)
`In addition, the implant 20 can be provided in the form of
`lation and scarring are decreased.
`20 a self-expanding foam, which can be injected through a tubu(cid:173)
`Referring to FIGS. 4 and 5, a second alternative embodi(cid:173)
`lar member 22 such as a needle or carmula in a metered
`ment of the present invention is shown. A prosthesis 10 fea(cid:173)
`amount. An appropriate amount of foam-forming materials
`tures two capsules, a larger, outer capsule 12 made of bio(cid:173)
`can be inserted through carmula 22 and allowed to expand or
`sorbable materials, and a smaller inner capsule 14 made of a
`form a matrix within the cavity created by the excised tissue.
`non-absorbable material. Inner capsule 14 also can be made
`Alternatively, a specialized, applicator may be used to inject
`partially resorbable as in the first alternative embodiment 25
`the desired amount of the foam. The amount of foam is
`above. Outer capsule 12 and inner capsule 14 can be separated
`preselected to allow sufficient expansion to fill the void left by
`by a thin layer 16 of saline or autologous fluids such as those
`the excision and support the surrounding tissue to prevent
`described above. Inner capsule 14 surrounds a more perma(cid:173)
`dimpling.
`nent member 18 made of autologous fluids or saline, for
`Following insertion of the implant, such as by an open
`example.
`method or one of the stereotactic methods described above,
`After implantation, outer capsule 12 dissolves, thus pre(cid:173)
`the resorbable implant occupies the breast tissue cavity and
`venting hardening by encapsulation of the prosthesis. The
`supports the surrounding tissue until such time as it resorbs or
`supply of fluid 16 between the capsules (a few to several
`biodegrades. After initial implantation, the patient's own flu-
`c.c.'s) is absorbed by the body once released by the dissolu(cid:173)
`35 ids, fibroblast, and stem cells, such adipocytes, vascular stem
`tion of outer capsule 12.
`cells, and others, permeates the sponge prosthesis. In the case
`Referring to FIG. 6, a further alternative embodiment of the
`of a small implant, such permeation would occur naturally,
`present invention includes an implant prosthesis 20 provided
`subsequent to implantation. In the case of a larger implant,
`in the form of a matrix framework, such as a sponge or foam.
`providing the implant at least partially filled with fluids prior
`The implant, which preferably is entirely biodegradable (re(cid:173)
`40 to implantation may be indicated.
`sorbable ), has a porous structure which supports the sur(cid:173)
`Advantageously, the new prosthesis decreases encapsula(cid:173)
`rounding tissue and provides a framework for the in-growth
`tion after implantation. Various biosorbable materials can be
`of fibrous tissue material. FIG. 6 illustrates tissue portion 24
`used in the implant of the present invention. Known biosorb(cid:173)
`surrounding implant 20 into which marker dye included in the
`able materials include polyglycolic acid (Dexon, Davis &
`implant, and described further below, has leached over time
`45 Geck); polyglactinmaterial (Vicryl, Ethicon); poliglecaprone
`from the implant, thereby marking the tissue. Accordingly, a
`(Monocryl, Ethicon); and synthetic absorbable lactomer 9-1
`surgeon performing a subsequent procedure easily will rec(cid:173)
`(Polysorb, United States Surgical Corporation).
`ognize the tissue surrounding the previous excision.
`Other foamable materials that can be utilized in the present
`According to a preferred embodiment, the implant is pro(cid:173)
`invention include, without limitation, proteins such as col-
`vided in the form of a foam or sponge which can be modified 50 lagen, fibronectin, laminin and fibrin, most preferably col(cid:173)
`by a surgeon prior to implantation, such as at a lumpectomy or
`lagen, and high molecular weight polysaccharides, such as
`biopsy site, simply by trimming the sponge to the appropriate
`heparan sulphate, chondroitin sulphate, hyaluronic acid and
`size and shape. Alternatively, the implant can be a pre-shaped
`dermatan sulphate. Mixtures of any of the aforementioned
`prosthesis of appropriate size, or an appropriate amount of
`materials also can be used, as required.
`foam or foam-forming materials. Optionally, the foam can be 55
`The materials can be modified, by cross-linking for
`provided as a self-expanding matrix that either is compressed,
`example, to control degradation rates over varying lengths of
`or forms in situ. Advantageously, the implant can be modified
`time, after which they are substantially or completely
`to correspond to the breast tissue that either has been
`resorbed.
`removed, requires replacement, or requires augmentation.
`Foams can be formed by various means known to those
`The foam or sponge matrix is sufficiently resilient to support 60
`skilled in the art, including injecting an aerosol into a gel, and
`the surrounding tissue without collapsing.
`freeze-drying aqueous dispersions of the foam-forming mate(cid:173)
`A preferred embodiment of implantation is illustrated
`rial. Foaming agents can be included to promote formation of
`schematically in FIG. 6, whereby the implant is elastically
`the foam. In addition, stabilizing agents can be included to
`compressible, and is delivered using a carmula or needle 22
`enhance foam stability. The foams can be extruded or formed
`inserted into the breast. A single implant 20 is shown being 65
`in situ.
`compressed so as to fit within carmula 22. A force is applied
`According to the present invention, these products may be
`mixed with one another or combined to provide various
`to drive the compressed implant distally through and out the
`
`30
`
`Focal Exhibit 1003 Page 5
`
`

`

`US 7,637,948 B2
`
`5
`resorption times or gradients, and/or may be interrelated with
`non-absorbable materials, such as polypropylene or PTFE
`(polytetrafluoroethylene) sold as (Gore-Tex®) material, for
`example. In an instance where a non-absorbable material is
`utilized, the non-resorbable implant section will remain par(cid:173)
`tially intact as a permanent structure.
`In each of the embodiment, the resorbable portions of the
`prosthesis ultimately biodegrades, and the patient is left with
`autologous tissue, some of which may have been implanted,
`ora permanent implant such as saline, as a filler for the biopsy 10
`cavity, thus preserving the contour of the breast and prevent(cid:173)
`ing indentation of the overlying skin.
`The implants of the present invention further can be
`instilled, before or after implantation, with indicated medi(cid:173)
`cines and other chemical or diagnostic agents. Examples of 15
`such agents include, but are not limited to, antibiotics, che(cid:173)
`motherapies, other cancer therapies, brachytherapeutic mate(cid:173)
`rial for local radiation effect, x-ray opaque or metallic mate(cid:173)
`rial for identification of the area, hemostatic material for
`control ofbleeding, growth factor hormones, immune system 20
`factors, gene therapies, biochemical indicators or vectors, and
`other types of therapeutic or diagnostic materials which may
`enhance the treatment of the patient.
`The breast implant preferably includes a permanent or
`temporary dye marker such as, but not limited to, indigo 25
`carmine or methylene blue. This marker serves as a visual
`identification of the area that has been biopsied or a lumpec(cid:173)
`tomy has been performed so that in the future an operating
`surgeon can identify the surrounding tissue before he violates
`the previously biopsied cavity. These dyes leach into the 30
`breast tissue giving the surgeon an indication when he is
`nearing the point of interest, that being a previous biopsy site
`particularly if it is positive for a cancer or if it is a site for
`which a lumpectomy has been previously performed and the
`pathologist advises us that there is residual cancer. The sur- 35
`geon can thus remove any of the surrounding breast tissue that
`contains dye and depending upon its concentration and the
`distance that it has traveled from the biopsy site will give us an
`indication of how much tissue should appropriately be
`removed.
`This dye may be integrated with a bioabsorbable material
`such as, but not limited to collagen or may be in a separate
`capsule that is inserted with the bioabsorbable material as
`well as a metallic device for radiographic identification.
`These two dyes are very dark colored dyes and these do 45
`leach through the breast tissue but will not stain the overlying
`skin.
`The present invention has been described particularly in
`connection with a breast implant, but it will be obvious to
`those of skill in the art that the invention can have application 50
`to other parts of the body, such as the face, and generally to
`other soft tissue or bone. Accordingly, the invention is appli(cid:173)
`cable to replacing missing or damaged soft tissue, structural
`tissue or bone, or for cosmetic tissue or bone replacement.
`Although the present invention has been described in rela- 55
`tion to particular embodiments thereof, many other variations
`and modifications and other uses will become apparent to
`those skilled in the art. It is preferred, therefore, that the
`present invention be limited not only by the specific disclo-
`sure herein, but only by the appended claims.
`
`40
`
`60
`
`What is claimed as new and desired to be protected by
`Letters Patent of the United States is:
`1. An implant system for filling a cavity formed by removal
`of soft tissue from a site within a patient's breast comprising:
`
`6
`an elongated delivery cannula having a proximal and a
`distal end and an inner lumen extending therein;
`a compressed resilient implant disposed within the inner
`lumen of the delivery catheter and formed of foamed or
`sponge matrix material which is at least in part bioab(cid:173)
`sorbable and which has a marking material, the implant
`being formed to fit the cavity in the patient's breast, and
`configured to support tissue surrounding the cavity
`when delivered thereto and expanded therein and to
`allow in-growth of fibrous tissue into and replacing at
`least a portion of the foamed or sponge matrix material.
`2. The implant system of claim 1, wherein the marking
`material is a dye.
`3. The implant system of claim 2, wherein the dye is one of
`indigo carmine and methylene blue.
`4. The implant system of claim 1, wherein the matrix
`material is elastically compressible.
`5. The implant system of claim 1, wherein the matrix
`material is formed of a foamed bioabsorbable protein.
`6. The implant system of claim 1, wherein the matrix
`material is formed of a foamed collagen.
`7. The implant system of claim 1, wherein the matrix
`contains at least one medicinal, therapeutic, or diagnostic
`substance.
`8. The implant system of claim 7, wherein the at least one
`substance is selected from the group consisting of radiation
`materials, antibiotics, chemotherapies, cancer therapeutics,
`hemostatic materials, hormone therapeutics, and radio(cid:173)
`graphic markers.
`9. The implant system of claim 1, wherein the implant has
`a shell containing the matrix material.
`10. The implant system of claim 9, wherein the shell com(cid:173)
`prises compressed matrix material.
`11. The implant system of claim 9, wherein the shell com(cid:173)
`pletely surrounds the matrix material.
`12. The implant system of claim 1 wherein the marker
`material is a radiographic element.
`13. The implant system of claim 12 wherein the radio(cid:173)
`graphic element is formed of a metallic material.
`14. A tissue marking implant system for filling a cavity
`formed by removal of soft tissue from a site within a patient's
`breast comprising:
`an elongated delivery cannula having a proximal and a
`distal end and an inner lumen extending therein;
`an expandable matrix of collagen material compressed
`within the inner lumen of the delivery carmula, the
`matrix having a porous structure configured for support(cid:173)
`ing tissue surrounding the cavity formed in the patient's
`breast and configured to provide a framework for the
`in-growth of fibrous tissue into the matrix when
`deployed from the distal end of the delivery cannula and
`disposed within the cavity formed in the patient's breast;
`and
`a dye marker supported by the matrix for dispersion within
`the cavity.
`15. The tissue implant of claim 14, wherein the porous
`structure of the matrix comprises a foam.
`16. The tissue implant of claim 14, wherein the porous
`structure of the matrix comprises a resilient framework which
`expands resiliently within the cavity in the patient's breast to
`support tissue surrounding the cavity.
`17. The tissue implant of claim 14, wherein the porous
`structure of the matrix is self-expanding within the patient's
`breast.
`
`* * * * *
`
`Focal Exhibit 1003 Page 6
`
`