Human implantable tissue expander

A human implantable tissue expander including a biocompatible implantable structural skeleton element having a predetermined overall three-dimensional shape and defining at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof and being operative, when implanted in human tissue, to permit fluid flow through the apertures and to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

FIELD OF THE INVENTION

The present invention relates to implantable tissue expanders.

BACKGROUND OF THE INVENTION

The following published patent documents are believed to represent the current state of the art:

French Patent Nos. 2,859,098 and 2,862,523; and

SUMMARY OF THE INVENTION

The present invention seeks to provide improved implantable tissue expanders.

There is thus provided in accordance with a preferred embodiment of the present invention a human implantable tissue expander including a biocompatible implantable structural skeleton element having a predetermined overall three-dimensional shape and defining at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof and being operative, when implanted in human tissue, to permit fluid flow through the apertures and to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

In accordance with a preferred embodiment of the present invention the human implantable tissue expander also includes at least one cap associated with an exterior of the skeleton element, the skeleton element being operative to maintain the at least one cap in a predetermined three-dimensional configuration generally independently of its orientation relative to gravitational acceleration. Preferably, the skeleton element is integrally formed with the at least one cap. Alternatively or additionally, the skeleton element and the cap are formed of the same material.

In accordance with another preferred embodiment of the present invention the skeleton element includes a plurality of ribs. Preferably, the skeleton element is operative when implanted in human tissue, to maintain a predetermined non-circularly symmetric three-dimensional configuration generally independently of its orientation relative to gravitational acceleration. Additionally or alternatively, the skeleton element is formed of one of polyurethane and silicone. Preferably, the skeleton element is formed by injection molding. Additionally or alternatively, the skeleton element is resilient.

In accordance with yet another preferred embodiment of the present invention the skeleton element is resiliently deformable to a deformed shape in which it has a substantially reduced minimum dimension, thereby to permit insertion of the skeleton element through an aperture in a cutaneous layer when the skeleton element is in the deformed shape and to allow the skeleton element, by virtue of its resiliency, to regain a desired original shape when placed at a desired location within the body.

There is also provided in accordance with another preferred embodiment of the present invention a human implantable tissue expander including a flexible enclosure for at least one material having at least one fluid flow characteristic and a flexible and resilient skeleton associated with the flexible enclosure and being operative to maintain the flexible enclosure in a predetermined three-dimensional configuration generally independently of its orientation relative to gravitational acceleration.

In accordance with a preferred embodiment of the present invention the flexible and resilient skeleton is integrally formed with the flexible enclosure. Preferably, the flexible and resilient skeleton and the flexible enclosure are formed of the same material.

In accordance with another preferred embodiment of the present invention the flexible and resilient skeleton includes a plurality of ribs. Preferably; the flexible and resilient skeleton is formed of one of polyurethane and silicone. Additionally or alternatively, the flexible and resilient skeleton is formed by injection molding.

In accordance with still another preferred embodiment of the present invention the flexible enclosure and the flexible and resilient skeleton are resiliently deformable to a deformed shape in which they have a substantially reduced overall minimum dimension, thereby to permit insertion of the flexible enclosure and the flexible and resilient skeleton through an aperture in a cutaneous layer when the flexible enclosure and the flexible and resilient skeleton are in the deformed shape and to allow the flexible enclosure and the flexible and resilient skeleton, by virtue of resiliency of the flexible and resilient skeleton, to regain a desired original shape when placed at a desired location within the body.

In accordance with yet another preferred embodiment of the present invention the at least one material is a gas. Alternatively, the at least one material is a liquid. As a further alternative, the at least one material is formed of particles.

In accordance with a further preferred embodiment of the present invention the flexible enclosure includes an injection port. Preferably, the flexible enclosure contains the at least one material. Additionally or alternatively, the flexible enclosure does not contain the at least one material when the flexible enclosure is inserted through the aperture.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made toFIGS. 1A-3B, which illustrate a breast tissue expander constructed and operative in accordance with a preferred embodiment of the present invention. The breast tissue expander ofFIGS. 1A-3Bis generally characterized in that it comprises a biocompatible, preferably resilient, implantable structural skeleton element100having a predetermined overall three-dimensional shape, defining at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof and being operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

The term “skeleton element” is used throughout to refer to an element which itself provides structural support and defines a predetermined three-dimensional shape, irrespective of whether and to what extent it is inflated or otherwise filled with a fluid or other material. It may thus be appreciated that a skeleton element is distinguished from prior art prostheses which comprise a flexible bag which is filled with a fluid or gel and whose three-dimensional shape is governed by the extent to which it is filled or is readily changeable in response to its orientation.

The skeleton element of the present invention may be incorporated in or associated with a fluid-filled enclosure to define a tissue expander. In such a case, the overall shape of the tissue expander is determined generally by the shape of the skeleton element rather than by the enclosure, the extent of its filling or its internal pressurization.

As seen inFIGS. 1A and 1B, the skeleton element100is typically in the shape of a truncated, generally conically-shaped coiled elongate element102having variously directed positioning barbs104located at base locations therealong. Elongate element102is preferably formed of a biocompatible plastic material, such as polyurethane or silicone. A suitable stiffener, such as a metal wire, may be incorporated in the elongate element102. Elongate element102preferably defines at least one wall portion106having formed therein apertures108, extending from an interior thereof to an exterior thereof, which are operative, when the breast tissue expander is implanted, to permit fluid flow therethrough.

As illustrated inFIG. 1C, it is a particular feature of a preferred embodiment of the present invention that skeleton element100is resiliently deformable from its normal shape, as shown inFIGS. 1A and 1Band designated generally inFIG. 1Cby reference numeral110, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral112, in which it has a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element100, in its deformed shape112, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element100, by virtue of its resiliency, to regain its normal shape110when placed at a desired location within the body (not shown).

Turning toFIGS. 2A and 2B, which illustrate the tissue expander in the form of skeleton element100implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element100, as it appears inFIGS. 1A and 1B, is maintained when the skeleton element100is implanted. Considering alsoFIGS. 3A and 3B, it is appreciated that the general three-dimensional configuration of the skeleton element100, as it appears inFIGS. 1A and 1B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 2B and 3B.

Reference is now made toFIGS. 4A-6B, which illustrate a breast tissue expander constructed and operative in accordance with another preferred embodiment of the present invention. The breast tissue expander ofFIGS. 4A-6Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element150entirely enclosed in a fluid enclosure152having a shape which is generally determined by the predetermined overall three-dimensional shape of the skeleton element150. The breast tissue expander ofFIGS. 4A-6Bis operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 4A and 4B, the skeleton element150is typically in the shape of a truncated, generally conically-shaped coiled elongate element154and the fluid enclosure152has variously directed positioning barbs156located at base locations therealong. Elongate element154is preferably formed of a biocompatible plastic material, such as polyurethane or silicone. A suitable stiffener, such as a metal wire, may be incorporated in the elongate element154. The fluid enclosure152is preferably formed of an elastomer, such as silicone, and preferably includes a conventional injection port158.

As illustrated inFIG. 4C, it is a particular feature of a preferred embodiment of the present invention that skeleton element150and fluid enclosure152are resiliently deformable from their normal shape, as shown inFIGS. 4A and 4Band designated generally inFIG. 4Cby reference numeral160, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral162, in which they have a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element150and the fluid enclosure152, in their deformed shape162, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element150and the fluid enclosure152, by virtue of the resiliency of the skeleton element, to regain their normal shape160when placed at a desired location within the body (not shown). It is appreciated that the skeleton element150may be separate from the fluid enclosure152as illustrated inFIG. 4C. Alternatively, the skeleton element150may be wholly or partially joined to the fluid enclosure152.

Turning toFIGS. 5A and 5B, which illustrate the tissue expander in the form of skeleton element150implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element150, as it appears inFIGS. 4A and 4B, is maintained when the tissue expander is implanted. Considering alsoFIGS. 6A and 6B, it is appreciated that the general three-dimensional configuration of the skeleton element150, as it appears inFIGS. 4A and 4B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 5B and 6B.

FIG. 5Cschematically illustrates changing the pressurization inside fluid enclosure152, as by injection of a fluid into the interior of the enclosure152via injection port158. Alternatively, a material formed of particles, which are preferably smaller in diameter than the diameter of the injection device, may be used to change the pressurization inside enclosure152. The change in pressurization may take place at any suitable time prior to or following implantation of the tissue expander.

Reference is now made toFIGS. 7A-9B, which illustrate a breast tissue expander constructed and operative in accordance with a further preferred embodiment of the present invention. The breast tissue expander ofFIGS. 7A-9Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element200having associated therewith a flexible cap202having a shape which is generally determined by the predetermined overall three-dimensional shape of the skeleton element200. The breast tissue expander ofFIGS. 7A-9Bdefines at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof is operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 7A and 7B, the skeleton element200is typically in the shape of a truncated, generally conically-shaped coiled elongate element204having variously directed positioning barbs206located at base locations therealong. Cap202and elongate element204are preferably formed of biocompatible plastic materials, such as polyurethane or silicone. A suitable stiffener, such as a metal wire, may be incorporated in the elongate element204. Elongate element204preferably defines at least one wall portion208having formed therein apertures210, extending from an interior thereof to an exterior thereof, which are operative, when the breast tissue expander is implanted, to permit fluid flow therethrough.

As illustrated inFIG. 7C, it is a particular feature of a preferred embodiment of the present invention that skeleton element200is resiliently deformable from its normal shape, as shown inFIGS. 7A and 7Band designated generally inFIG. 7Cby reference numeral212, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral214, in which it has a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element200, in its deformed shape214, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element200, by virtue of its resiliency, to regain its normal shape212when placed at a desired location within the body (not shown).

Turning toFIGS. 8A and 8B, which illustrate the tissue expander in the form of skeleton element200implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element200, as it appears inFIGS. 7A and 7B, is maintained when the tissue expander is implanted. Considering alsoFIGS. 9A and 9B, it is appreciated that the general three-dimensional configuration of the skeleton element200, as it appears inFIGS. 7A and 7B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 8B and 9B.

Reference is now made toFIGS. 10A-12B, which illustrate a breast tissue expander constructed and operative in accordance with yet another preferred embodiment of the present invention. The breast tissue expander ofFIGS. 10A-12Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element250having a predetermined overall three-dimensional shape and being operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 10A and 10B, the skeleton element250has a generally conical shape having a generally hemispherical vertex252. Skeleton element250includes a plurality of generally circular discs254extending radially outward from a core256(FIGS. 11B and 12B) and additionally supported by ribs258, defining at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof, which are operative, when the breast tissue expander is implanted, to permit fluid flow therethrough.

Skeleton element250preferably defines at least one wall portion260having formed therein apertures262, extending from an interior thereof to an exterior thereof, Variously directed positioning barbs264are located on a base disc266located at base locations therealong. Skeleton element250is preferably formed of a biocompatible plastic material as polyurethane or silicone.

As illustrated inFIG. 10C, it is a particular feature of a preferred embodiment of the present invention that skeleton element250is resiliently deformable from its normal shape, as shown inFIGS. 10A and 10Band designated generally inFIG. 10Cby reference numeral268, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral270, in which it has a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element250, in its deformed shape270, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element250, by virtue of its resiliency, to regain its normal shape268when placed at a desired location within the body (not shown).

Turning toFIGS. 11A and 11B, which illustrate the tissue expander in the form of skeleton element250implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element250, as it appears inFIGS. 10A and 10B, is maintained when the skeleton element250is implanted. Considering alsoFIGS. 12A and 12B, it is appreciated that the general three-dimensional configuration of the skeleton element250, as it appears inFIGS. 10A and 10B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 11B and 12B.

Reference is now made toFIGS. 13A-15B, which illustrate a breast tissue expander constructed and operative in accordance with still another preferred embodiment of the present invention. The breast tissue expander ofFIGS. 13A-15Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element300entirely enclosed in a fluid enclosure302having a shape which is generally determined by the predetermined overall three-dimensional shape of the skeleton element300. The breast tissue expander ofFIGS. 13A-15Bis operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 13A and 13B, the skeleton element300has a generally conical shape having a generally hemispherical vertex304. Skeleton element300is formed of a plurality of generally circular discs306extending radially outward from a core308(FIGS. 14B and 15B) and additionally supported by ribs310. Variously directed positioning barbs312are located on a base disc314located at base locations therealong. Skeleton element300is preferably formed of a biocompatible plastic material, such as polyurethane or silicone. The fluid enclosure302is preferably formed of an elastomer, such as silicone, and preferably includes a conventional injection port318.

As illustrated inFIG. 13C, it is a particular feature of a preferred embodiment of the present invention that skeleton element300and fluid enclosure302are resiliently deformable from their normal shape, as shown inFIGS. 13A and 13Band designated generally inFIG. 13Cby reference numeral320, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral322, in which they have a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element300and the fluid enclosure302, in their deformed shape322, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element300and the fluid enclosure302, by virtue of the resiliency of the skeleton element, to regain their normal shape320when placed at a desired location within the body (not shown). It is appreciated that the skeleton element300may be separate from the fluid enclosure302as illustrated inFIG. 13C. Alternatively, the skeleton element300may be wholly or partially joined to the fluid enclosure302.

Turning toFIGS. 14A and 14B, which illustrate the tissue expander in the form of skeleton element300implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element300, as it appears inFIGS. 13A and 13B, is maintained when the skeleton element300is implanted. Considering alsoFIGS. 15A and 15B, it is appreciated that the general three-dimensional configuration of the skeleton element300, as it appears inFIGS. 13A and 13B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 14B and 15B.

It is appreciated that the pressurization inside fluid enclosure302may be changed, as by injection of a gas or a liquid into the interior of the enclosure302via a suitable injection port, such as injection port318. Alternatively, a material formed of particles, which are preferably smaller in diameter than the diameter of the injection device (not shown), may be used to change the pressurization inside enclosure302. Such a change in pressurization may take place at any suitable time prior to or following implantation of the tissue expander.

Reference is now made toFIGS. 16A-18B, which illustrate a breast tissue expander constructed and operative in accordance with still another preferred embodiment of the present invention. The breast tissue expander ofFIGS. 16A-18Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element350having a predetermined overall three-dimensional shape and being operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 16A and 16B, the skeleton element350is typically in the shape of a cage formed of a generally parallel array of differently sized and shaped bent elongate elements352which are held together by one or more transverse elongate elements, here including a surrounding elongate element354and two other elongate elements, designated respectively by reference numerals356and358. Skeleton element350preferably defines at least one wall portion360having formed therein apertures362, extending from an interior thereof to an exterior thereof, which are operative, when the breast tissue expander is implanted, to permit fluid flow therethrough.

It is appreciated that one or more of the various bent elongate elements352,354,356and358may have differing mechanical characteristics such as stiffness and resiliency. The skeleton element350may be integrally formed, as by injection molding. The skeleton element350may include variously directed positioning barbs363located at base locations therealong, and is preferably formed of a biocompatible plastic material, such as polyurethane or silicone.

As seen inFIG. 16C, which illustrates the breast tissue expander ofFIGS. 16A and 16Brotated by approximately 45 degrees counter clockwise with respect to the orientation shown inFIG. 16A, it is a particular feature of a preferred embodiment of the present invention that skeleton element350is resiliently deformable from its normal shape, as shown inFIGS. 16A and 16Band designated generally inFIG. 16Cby reference numeral364, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral366, in which it has a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element350, in its deformed shape366, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element350, by virtue of its resiliency, to regain its normal shape364when placed at a desired location within the body (not shown).

Turning toFIGS. 17A and 17B, which illustrate the tissue expander in the form of skeleton element350implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element350, as it appears inFIGS. 17A and 17B, is maintained when the skeleton element350is implanted. Considering alsoFIGS. 18A and 18B, it is appreciated that the general three-dimensional configuration of the skeleton element350, as it appears inFIGS. 18A and 18B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 17B and 18B.

Reference is now made toFIGS. 19A-21B, which illustrate a breast tissue expander constructed and operative in accordance with still another preferred embodiment of the present invention. The breast tissue expander ofFIGS. 19A-21Bis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element400entirely enclosed in a fluid enclosure402having a shape which is generally determined by the predetermined overall three-dimensional shape of the skeleton element400. The breast tissue expander ofFIGS. 19A-21Bis operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 19A and 19B, the skeleton element400is typically in the shape of a cage formed of a generally parallel array of differently sized and shaped bent elongate elements404which are held together by one or more transverse elongate elements, here including a surrounding elongate element406and two other elongate elements, designated respectively by reference numerals408and410. It is appreciated that one or more of the various bent elongate elements404,406,408and410may have differing mechanical characteristics such as stiffness and resiliency. The skeleton element400may be integrally formed, as by injection molding, and is preferably formed of a biocompatible plastic material, such as polyurethane or silicone.

The fluid enclosure402may include variously directed positioning barbs412located at base locations therealong. The fluid enclosure402is preferably formed of an elastomer, such as silicone, and preferably includes a conventional injection port414.

As seen inFIG. 19C, which illustrates the breast tissue expander ofFIGS. 19A and 19Brotated by approximately 45 degrees counter clockwise with respect to the orientation shown inFIG. 19A, it is a particular feature of a preferred embodiment of the present invention that skeleton element400and fluid enclosure402are resiliently deformable from their normal shape, as shown inFIGS. 19A and 19Band designated generally inFIG. 19Cby reference numeral420, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral422, in which they have a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element400and the fluid enclosure402, in their deformed shape422, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element400and the fluid enclosure402, by virtue of the resiliency of the skeleton element, to regain their normal shape420when placed at a desired location within the body (not shown). It is appreciated that the skeleton element400may be separate from the fluid enclosure402as illustrated inFIG. 19C. Alternatively, the skeleton element400may be wholly or partially joined to the fluid enclosure402.

Turning toFIGS. 20A and 20B, which illustrate the tissue expander in the form of skeleton element400implanted in a breast, it is seen that the general three-dimensional configuration of the skeleton element400, as it appears inFIGS. 19A and 19B, is maintained when the skeleton element400is implanted. Considering alsoFIGS. 21A and 21B, it is appreciated that the general three-dimensional configuration of the skeleton element400, as it appears inFIGS. 19A and 19B, is maintained essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 20B and 21B.

It is appreciated that the pressurization inside fluid enclosure402may be changed, as by injection of a gas or a liquid into the interior of the enclosure402via a suitable injection port, such as injection port414. Alternatively, a material formed of particles, which are preferably smaller in diameter than the diameter of the injection device (not shown), may be used to change the pressurization inside enclosure402. Such a change in pressurization may take place at any suitable time prior to or following implantation of the tissue expander.

Reference is now made toFIGS. 22A-22C, which illustrate a tissue expander constructed and operative in accordance with a further preferred embodiment of the present invention. The tissue expander ofFIGS. 22A-22Cis generally characterized in that it comprises a biocompatible resilient implantable structural skeleton element500having associated therewith a flexible cap502having a shape, which is generally determined by the predetermined overall three-dimensional shape of the skeleton element500. The tissue expander ofFIGS. 22A-22Cdefines at least one wall portion having formed therein apertures extending from an interior thereof to an exterior thereof and is operative, when implanted in human tissue, to generally maintain the predetermined three-dimensional shape generally independently of its orientation relative to gravitational acceleration.

As seen inFIGS. 22A and 22B, the skeleton element500is typically in the shape of a truncated, generally conically-shaped coiled elongate element504and the cap502is preferably formed with variously directed positioning barbs506located on a base508. Cap502and elongate element504are preferably formed of biocompatible plastic materials, such as polyurethane or silicone. A suitable stiffener, such as a metal wire, may be incorporated in the elongate element504. Elongate element504preferably defines at least one wall portion510having formed therein apertures512, extending from an interior thereof to an exterior thereof, which are operative, when the tissue expander is implanted, to permit fluid flow therethrough.

As illustrated inFIG. 22C, it is a particular feature of a preferred embodiment of the present invention that skeleton element500is resiliently deformable from its normal shape, as shown inFIGS. 22A and 228and designated generally inFIG. 22Cby reference numeral514, having a minimum dimension L1, to a deformed shape, designated generally by reference numeral516, in which it has a substantially reduced minimum dimension L2, thereby to permit insertion of the skeleton element500, in its deformed shape516, through an aperture (not shown) in a cutaneous layer (not shown) and to allow the skeleton element500, by virtue of its resiliency, to regain its normal shape514when placed at a desired location within the body (not shown).

Reference is now made toFIGS. 23A,23B and23C, which are simplified pictorial illustrations of tissue expanders of the type shown inFIGS. 22A and 22Bimplanted in the buttocks of a patient.

It is seen that the general three-dimensional configuration of the skeleton element500is maintained when the buttocks expander is implanted, and is essentially unchanged irrespective of whether the patient is standing or lying prone, as shown by distance A inFIGS. 23B and 23C.

It is appreciated that the tissue expanders described hereinabove with reference toFIGS. 1A-23Care examples of various types of tissue expanders not limited in their application to breasts and buttocks. Similar tissue expanders may be utilized to expand any suitable human tissue.

It is appreciated that some or all of the biocompatible materials employed in the tissue expanders described hereinabove may contain medicinal materials which may be released into the surrounding tissue or into the fluid enclosure at a desired rate.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as modifications and variations thereof as would occur to a person of skill in the art upon reading the foregoing specification and which are not in the prior art.