CA2007883C - Plastic surgery device - Google Patents
Plastic surgery deviceInfo
- Publication number
- CA2007883C CA2007883C CA 2007883 CA2007883A CA2007883C CA 2007883 C CA2007883 C CA 2007883C CA 2007883 CA2007883 CA 2007883 CA 2007883 A CA2007883 A CA 2007883A CA 2007883 C CA2007883 C CA 2007883C
- Authority
- CA
- Canada
- Prior art keywords
- implants
- implant device
- soft tissue
- porous
- network
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Prostheses (AREA)
- Materials For Medical Uses (AREA)
Abstract
A novel plastic surgery implant device is disclosed in which the surface region is porous and has a network of interconnected pores. Soft tissue grows into the porous surface region and stabilizes the location of the implant device in its soft tissue environment.
Description
`- I 2~7~
TITLE OF lNv~r.~lON
PLASTIC SURGERY DEVICE
FIELD OF INVENTION
The present invention relates to plastic surgery devices and, in particular, to plastic surgery devices which achieve a more secure fixation than has previously been the case.
BACRGROUND TO THE lNV~r. l-lON
Reconstruction and cosmetic surgery is conducted on many parts of the human body, for example, the human breast. Such surgery often involves the implantation of bulking material within the existing tissue to augment existing tissue for cosmetic effect or to reconstruct surgically-removed tissue or to correct deformities.
Generally, such implantation is effected using a bulking member, which may be of a variety of shapes, depending on the effect desired.
Difficulties arise, however, with such conventional implants. Scar tissue forms around and encloses the implant. However, before such scar tissue can form, fluid often collects around the implant, which may be blood, and can lead to painful infections. In addition, the scar may contract in situ, causing discomfort and perhaps deformity. Such implants have been known to change orientation and even invert, which again leads to discomfort and deformity if the implant is of complex shape. Further, migration of the implant within the breast tissue is known, particularly in persons lacking good tissue, again with consequent discomfort and deformity.
A review Article describing augmentation mammaplasty generally and problems associated therewith was published by Fritz E. Barton, Jr., in Selected Readings in Plastic Surgery, Vol. 3, No. 29, Dec. 1985.
Further details of the prior art problems can be obtained by reference thereto.
TITLE OF lNv~r.~lON
PLASTIC SURGERY DEVICE
FIELD OF INVENTION
The present invention relates to plastic surgery devices and, in particular, to plastic surgery devices which achieve a more secure fixation than has previously been the case.
BACRGROUND TO THE lNV~r. l-lON
Reconstruction and cosmetic surgery is conducted on many parts of the human body, for example, the human breast. Such surgery often involves the implantation of bulking material within the existing tissue to augment existing tissue for cosmetic effect or to reconstruct surgically-removed tissue or to correct deformities.
Generally, such implantation is effected using a bulking member, which may be of a variety of shapes, depending on the effect desired.
Difficulties arise, however, with such conventional implants. Scar tissue forms around and encloses the implant. However, before such scar tissue can form, fluid often collects around the implant, which may be blood, and can lead to painful infections. In addition, the scar may contract in situ, causing discomfort and perhaps deformity. Such implants have been known to change orientation and even invert, which again leads to discomfort and deformity if the implant is of complex shape. Further, migration of the implant within the breast tissue is known, particularly in persons lacking good tissue, again with consequent discomfort and deformity.
A review Article describing augmentation mammaplasty generally and problems associated therewith was published by Fritz E. Barton, Jr., in Selected Readings in Plastic Surgery, Vol. 3, No. 29, Dec. 1985.
Further details of the prior art problems can be obtained by reference thereto.
2~ 883 -SUMMARY OF lNvh~llON
In accordance with the present invention, there is provided a novel plastic surgery implant device comprising a body having the shape and dimensions corresponding to the desired plastic surgery, having at least a portion of the outer surface of said body provided with a three-dimensional network of interconnected pores. The network of interconnected pores permits soft tissue engaging the surface of the plastic surgery implant device to grow through surface pores and into the subsurface network. The tissue ingrowth, in effect, incorporates the plastic surgery implant device into the tissue, thereby, eliminating the prior art problems discussed above.
DESCRIPTION OF ~K~hKKh~ EMBODIMENT
The present invention is applicable to a wide variety of plastic surgery devices which are required to be located within a soft tissue environment in the human body. In each case, a porous surface is provided, which permits the ingrowth of soft tissue into the surface of the implant, to provide a stable location of the implant, as a result of ingrowth of soft tissue into the porous surface.
Among the plastic surgery devices to which the present invention is directed are mammary implants, tissue expander implants, nipple implants, vaginal stents, muscle implants, chin implants, otoplasty implants, orbitalplasty implants, rhinoplasty implants and trimmable blocks and sheats.
The implant devices to which the present invention is directed may take a variety of physical forms and shapes. The common element is the provision of a porous coating to permit ingrowth of soft tissue to achieve the desired fixation of location in its soft tissue environment. Generally, such implants take one of three physical forms, namely solid, hollow and pre-2(~)7883 -filled with gel material, or inflatable with a cavity for receipt of an inflating medium, such as gel, saline or air. In the latter structure, the implant sometimes is positioned in the desired location and then inflated to the desired degree of inflation in situ. The implant devices are formed with at least the tissue-contacting portions thereof formed of polymeric biocompatible materials which do not biodegrade.
One particular form of plastic surgery implant device to which the present invention is applicable is breast implants. Such breast implants may have any desired shape, which may have a round and domed structure of low or high profile, be of teardrop shape, of georgiade contour, or of any other convenient shape.
Such implants are pliable and generally have a liquid filling an enclosure to provide such pliability. The liquid usually is a gel, saline solution or a combination of the two. The enclosure is usually constructed of silicone rubber as a result of its flexibility and lack of toxicity.
As noted above, it is essential to the present invention to provide a porous surface structure on the implant device comprising a network of interconnected pores, to permit the ingrowth of soft tissue into the surface and incorporate the implant into its environment.
FORMATION OF POROUS SURFACE
A variety of techn;ques may be employed to form a porous surface in polymeric materials, which are the usual materials of construction of the implants. In one such procedure, the porous polymer structure may be formed by uniformly dispersing solvent-elutable particles in a continuous or discontinuous polymer phase, forming a coherent-shaped article from the dispersion having solvent-elutable particles substantially uniformly dispersed throughout the 2(~)7883 _ continuous solid polymer phase, and eluting the solvent-elutable particles from the article to provide a porous coated polymer product having interconnected pores therein.
A number of specific procedures may be utilized to carry out the above-described process, the particular one chosen depending on the shape of product desired, the nature of the polymer used and the form of product desired. One such procedure involves pulverizing the polymer to the required particle size, mixing the powder with solvent-elutable particles and compressing the mixture at pressures below about 100 psi and at a temperature in the range of about 20 to about 350F.
The compressed mixture may be molded or extruded to the desired shape and the resulting coherent-shaped article is leached to remove the solvent-elutable particles.
Another specific procedure which may be used involves blending together a moldable and/or extrudible, flexible polymer material and solvent-elutable particles in sufficient quantities to provide a continuous phase of polymer and a dispersed phase of solvent-elutable particles in the blend. Thereafter, the blend is molded or extruded to the desired shape and contacted with solvent to remove the solvent-elutable particles and leave an open network of interconnected pores throughout the body.
In a modification of this procedure, the polymer may be provided as a solution into which the polymer particles are mixed. After removal of the solvent, the molding or extruding and leaching operations are carried out.
Yet another specific procedure for forming the microporous polymer product involves initial formation of beads of polymer having a core of solvent-elutable material by polymer solution coating of the core material, compression molding or extruding of the beads 2t~7~383 .,_ to the desired shape and leaching the product to remove the solvent-elutable material.
A further specific procedure for the formation of a microporous polymeric product includes forming a viscous casting solution of the polymer, dispersing the solvent-elutable particles in the solution, casting the solution on to a casting surface, which may be the desired surface of the implant, and, after removal of solvent, eluting the solvent-elutable particles from the casted material.
Alternatively, where a sheet of porous material is to be formed, a tube of porous material first is formed and then is slit longitudinally to form the sheet. The tube may be formed by the viscous casting solution which is cast in a tube of inside diameter corresponding to the outside diameter of the desired tube. A plumb ball or other suitable device, such as a rod, of diameter corresponding to the desired inside diameter of the tube is drawn through the column of viscous material, resulting in the casting of the polymer on the inside of the tube.
Following drying of the casting, the polymer tube is removed, and the particles eluted to provide the porous structure. Following the elution step, the structure of the device, including its porosity, may be modified if desired, by heat treatment, such as, in an autoclave.
The solvent-elutable particles and the elution solvent used in the above described procedure preferably should be non-toxic in nature so that any residual material in the porous structure is not harmful to body tissues or blood in use. Typically, solvent-elutable particles are water-soluble, for example, sodium chloride or sodium carbonate particles, and solvent elution is achieved using water.
- Z~ 33 The particle size of the elutable particles to a large degree dictates the pore size in the polymer body, although irregular pore shapes generally result. Pore sizes from about 10 to about 500 microns are possible, 5using particles in the range of about -500 to about +100 mesh.
The pore size, volume and shape of the product may be controlled by varying the size, shape and distribution of the solvent-elutable particles and the 10weight ratio of the polymer, to achieve the properties desired in the end product, as described in more detail below.
Another procedure for the formation of a porous polymeric material is to cast the polymer around a 15lattice-work which then may be rolled or formed into the desired shape.
A further procedure for formation of a porous polymeric material involves providing a powdered solid polymer phase and a solvent phase including a solvent 20for the polymer. The liquid monomer phase is drawn rapidly through the polymer particles so as to allow dissolving of polymer at the surface of the polymer particles only and to cause the formation of particle-to-particle joints.
25The wholly porous product formed in this latter procedure may be combined with a rigid polymeric member, which may be the surface of the implant, to form a composite structure, if desired, as described in more detail below.
30The parameters of the porous surface should be such as to permit tissue ingrowth so as to stabilize the location of the implant.
The porous coating required in accordance with the present invention may wholly cover the outer surface of 35the implant or only partially so, depending on the 2~a~883 .
nature of the implant and its intended location in the human body.
The porous coating may be provided by direct coating or by physical modifications to the surface of the implant. Alternatively, a separate sheet of porous material may be provided, which then may be bonded to or wrapped about the external surface of the device. A
further alternative is to form the porous sheet material to the shape of the device, such as by thermal forming before associating the shaped sheet with the implant.
Where such a porous sheet is employed, the porous sheet may be wholly porous or may be formed as a composite of a porous surface adhered to a coherent substrate, either by in situ formation or by lamination.
Any of the procedures described above may be employed to form such sheet material. Another procedure which may be adopted involves winding of a thread of suitable material on a shaped mandrel and then cutting the resulting porous structure to form a sheet, such as is described in U.S. Patent No. 4,475,972.
The interstitial pore size of the network of interconnected pores is sufficient to permit ingrowth of soft tissue and generally ranges from about 20 to about 500 microns, preferably about 20 to about 50 microns.
The network of interconnected pores has a porosity which ranges from about 10 to about 90~, preferably about 35 to about 85%. The porous surface region of the implant provided in accordance with this invention generally has a thickness from about 50 microns to about lmm, preferably about 50 microns to about 250 microns.
SUMMARY OF DISCLOSURE
In summary of this disclosure, the present invention provides a novel plastic surgery implant device which does not suffer from the drawbacks of the prior art in that the porous surface promotes a stable location within the soft tissue environment.
- 2(~71 38~
~ ..
Modifications are possible within the scope of this invention.
In accordance with the present invention, there is provided a novel plastic surgery implant device comprising a body having the shape and dimensions corresponding to the desired plastic surgery, having at least a portion of the outer surface of said body provided with a three-dimensional network of interconnected pores. The network of interconnected pores permits soft tissue engaging the surface of the plastic surgery implant device to grow through surface pores and into the subsurface network. The tissue ingrowth, in effect, incorporates the plastic surgery implant device into the tissue, thereby, eliminating the prior art problems discussed above.
DESCRIPTION OF ~K~hKKh~ EMBODIMENT
The present invention is applicable to a wide variety of plastic surgery devices which are required to be located within a soft tissue environment in the human body. In each case, a porous surface is provided, which permits the ingrowth of soft tissue into the surface of the implant, to provide a stable location of the implant, as a result of ingrowth of soft tissue into the porous surface.
Among the plastic surgery devices to which the present invention is directed are mammary implants, tissue expander implants, nipple implants, vaginal stents, muscle implants, chin implants, otoplasty implants, orbitalplasty implants, rhinoplasty implants and trimmable blocks and sheats.
The implant devices to which the present invention is directed may take a variety of physical forms and shapes. The common element is the provision of a porous coating to permit ingrowth of soft tissue to achieve the desired fixation of location in its soft tissue environment. Generally, such implants take one of three physical forms, namely solid, hollow and pre-2(~)7883 -filled with gel material, or inflatable with a cavity for receipt of an inflating medium, such as gel, saline or air. In the latter structure, the implant sometimes is positioned in the desired location and then inflated to the desired degree of inflation in situ. The implant devices are formed with at least the tissue-contacting portions thereof formed of polymeric biocompatible materials which do not biodegrade.
One particular form of plastic surgery implant device to which the present invention is applicable is breast implants. Such breast implants may have any desired shape, which may have a round and domed structure of low or high profile, be of teardrop shape, of georgiade contour, or of any other convenient shape.
Such implants are pliable and generally have a liquid filling an enclosure to provide such pliability. The liquid usually is a gel, saline solution or a combination of the two. The enclosure is usually constructed of silicone rubber as a result of its flexibility and lack of toxicity.
As noted above, it is essential to the present invention to provide a porous surface structure on the implant device comprising a network of interconnected pores, to permit the ingrowth of soft tissue into the surface and incorporate the implant into its environment.
FORMATION OF POROUS SURFACE
A variety of techn;ques may be employed to form a porous surface in polymeric materials, which are the usual materials of construction of the implants. In one such procedure, the porous polymer structure may be formed by uniformly dispersing solvent-elutable particles in a continuous or discontinuous polymer phase, forming a coherent-shaped article from the dispersion having solvent-elutable particles substantially uniformly dispersed throughout the 2(~)7883 _ continuous solid polymer phase, and eluting the solvent-elutable particles from the article to provide a porous coated polymer product having interconnected pores therein.
A number of specific procedures may be utilized to carry out the above-described process, the particular one chosen depending on the shape of product desired, the nature of the polymer used and the form of product desired. One such procedure involves pulverizing the polymer to the required particle size, mixing the powder with solvent-elutable particles and compressing the mixture at pressures below about 100 psi and at a temperature in the range of about 20 to about 350F.
The compressed mixture may be molded or extruded to the desired shape and the resulting coherent-shaped article is leached to remove the solvent-elutable particles.
Another specific procedure which may be used involves blending together a moldable and/or extrudible, flexible polymer material and solvent-elutable particles in sufficient quantities to provide a continuous phase of polymer and a dispersed phase of solvent-elutable particles in the blend. Thereafter, the blend is molded or extruded to the desired shape and contacted with solvent to remove the solvent-elutable particles and leave an open network of interconnected pores throughout the body.
In a modification of this procedure, the polymer may be provided as a solution into which the polymer particles are mixed. After removal of the solvent, the molding or extruding and leaching operations are carried out.
Yet another specific procedure for forming the microporous polymer product involves initial formation of beads of polymer having a core of solvent-elutable material by polymer solution coating of the core material, compression molding or extruding of the beads 2t~7~383 .,_ to the desired shape and leaching the product to remove the solvent-elutable material.
A further specific procedure for the formation of a microporous polymeric product includes forming a viscous casting solution of the polymer, dispersing the solvent-elutable particles in the solution, casting the solution on to a casting surface, which may be the desired surface of the implant, and, after removal of solvent, eluting the solvent-elutable particles from the casted material.
Alternatively, where a sheet of porous material is to be formed, a tube of porous material first is formed and then is slit longitudinally to form the sheet. The tube may be formed by the viscous casting solution which is cast in a tube of inside diameter corresponding to the outside diameter of the desired tube. A plumb ball or other suitable device, such as a rod, of diameter corresponding to the desired inside diameter of the tube is drawn through the column of viscous material, resulting in the casting of the polymer on the inside of the tube.
Following drying of the casting, the polymer tube is removed, and the particles eluted to provide the porous structure. Following the elution step, the structure of the device, including its porosity, may be modified if desired, by heat treatment, such as, in an autoclave.
The solvent-elutable particles and the elution solvent used in the above described procedure preferably should be non-toxic in nature so that any residual material in the porous structure is not harmful to body tissues or blood in use. Typically, solvent-elutable particles are water-soluble, for example, sodium chloride or sodium carbonate particles, and solvent elution is achieved using water.
- Z~ 33 The particle size of the elutable particles to a large degree dictates the pore size in the polymer body, although irregular pore shapes generally result. Pore sizes from about 10 to about 500 microns are possible, 5using particles in the range of about -500 to about +100 mesh.
The pore size, volume and shape of the product may be controlled by varying the size, shape and distribution of the solvent-elutable particles and the 10weight ratio of the polymer, to achieve the properties desired in the end product, as described in more detail below.
Another procedure for the formation of a porous polymeric material is to cast the polymer around a 15lattice-work which then may be rolled or formed into the desired shape.
A further procedure for formation of a porous polymeric material involves providing a powdered solid polymer phase and a solvent phase including a solvent 20for the polymer. The liquid monomer phase is drawn rapidly through the polymer particles so as to allow dissolving of polymer at the surface of the polymer particles only and to cause the formation of particle-to-particle joints.
25The wholly porous product formed in this latter procedure may be combined with a rigid polymeric member, which may be the surface of the implant, to form a composite structure, if desired, as described in more detail below.
30The parameters of the porous surface should be such as to permit tissue ingrowth so as to stabilize the location of the implant.
The porous coating required in accordance with the present invention may wholly cover the outer surface of 35the implant or only partially so, depending on the 2~a~883 .
nature of the implant and its intended location in the human body.
The porous coating may be provided by direct coating or by physical modifications to the surface of the implant. Alternatively, a separate sheet of porous material may be provided, which then may be bonded to or wrapped about the external surface of the device. A
further alternative is to form the porous sheet material to the shape of the device, such as by thermal forming before associating the shaped sheet with the implant.
Where such a porous sheet is employed, the porous sheet may be wholly porous or may be formed as a composite of a porous surface adhered to a coherent substrate, either by in situ formation or by lamination.
Any of the procedures described above may be employed to form such sheet material. Another procedure which may be adopted involves winding of a thread of suitable material on a shaped mandrel and then cutting the resulting porous structure to form a sheet, such as is described in U.S. Patent No. 4,475,972.
The interstitial pore size of the network of interconnected pores is sufficient to permit ingrowth of soft tissue and generally ranges from about 20 to about 500 microns, preferably about 20 to about 50 microns.
The network of interconnected pores has a porosity which ranges from about 10 to about 90~, preferably about 35 to about 85%. The porous surface region of the implant provided in accordance with this invention generally has a thickness from about 50 microns to about lmm, preferably about 50 microns to about 250 microns.
SUMMARY OF DISCLOSURE
In summary of this disclosure, the present invention provides a novel plastic surgery implant device which does not suffer from the drawbacks of the prior art in that the porous surface promotes a stable location within the soft tissue environment.
- 2(~71 38~
~ ..
Modifications are possible within the scope of this invention.
Claims (8)
1. A plastic surgery implant device useful for reconstruction and cosmetic surgery in an implanted soft tissue environment in the human body, comprising:
a body having the shape and dimensions corresponding to the desired plastic surgery to effect the reconstruction and cosmetic surgery, and at least a portion of an outer soft tissue-engaging surface being porous and formed of polymeric biocompatible material resistant to biodegradation and provided with a network of interconnected pores to engage soft tissue in the implanted environment, the network of pores being dimensioned to permit growth of soft tissue into the porous surface to stabilize the location of the plastic surgery implant device in its implanted soft tissue environment.
a body having the shape and dimensions corresponding to the desired plastic surgery to effect the reconstruction and cosmetic surgery, and at least a portion of an outer soft tissue-engaging surface being porous and formed of polymeric biocompatible material resistant to biodegradation and provided with a network of interconnected pores to engage soft tissue in the implanted environment, the network of pores being dimensioned to permit growth of soft tissue into the porous surface to stabilize the location of the plastic surgery implant device in its implanted soft tissue environment.
2. The implant device claimed in claim 1, wherein the network of interconnected pores has an interstitial pore size of from about 20 to about 500 microns.
3. The implant device claimed in claim 2, wherein the network of interconnected pores has an interstitial pore size of from about 20 to about 50 microns.
4. The implant device claimed in claim 3, wherein the network of interconnected pores has a porosity of about 10 to about 90%.
5. The implant device claimed in claim 4, wherein the porosity is about 35% to about 85%.
6. The implant device claimed in any one of claims 1, 2, 3, 4 or 5, characterized in that the porous surface has a thickness of about 50 microns to about 1 mm.
7. The implant device claimed in claim 6, characterized in that the porous surface has a thickness of about 50 microns to about 250 microns.
8. The implant device claimed in clalim 1, 2, 3, 4, 5, 6 or 7 which is selected from the group consisting of mammary implants, tissue expander implants, nipple implants, vaginal stents, muscle implants, chin implants, otoplasty implants, orbitoplasty implants and rhinoplasty implants.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US332,850 | 1981-12-21 | ||
| US33285089A | 1989-02-28 | 1989-02-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2007883A1 CA2007883A1 (en) | 1990-08-31 |
| CA2007883C true CA2007883C (en) | 1995-12-26 |
Family
ID=23300120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2007883 Expired - Fee Related CA2007883C (en) | 1989-02-28 | 1990-01-16 | Plastic surgery device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2007883C (en) |
-
1990
- 1990-01-16 CA CA 2007883 patent/CA2007883C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2007883A1 (en) | 1990-08-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |