US20020068974A1 - Expandable porous mesh bag device and methods of use for reduction, filling, fixation and supporting of bone - Google Patents

Abstract

Expandable fabric bags and methods of use for reduction, fixation, support and treatment of bone abnormalities such as tibial plateau fractures, femoral head necrosis, compression fractures of the spine and other bone abnormalities.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims priority from U.S. provisional application 60/219,853 filed Jul. 21, 2000, the entirety of which is incorporated herein by reference.[0001]
BACKGROUND OF THE INVENTION
• This invention relates to methods and devices for correcting bone abnormalities and involves use of a surgical mesh bag which is inserted into a prepared cavity in bone. The bag is inflated using bone replacement material to expand and fill the cavity.[0002]
• U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich describe a device and method for stabilizing the spinal segment with an expandable, porous fabric implant for insertion into the interior of a reamed out disc which is packed with material to facilitate bony fusion. In the present invention, a similar bag is used to correct bone abnormalities including, but not limited to, bone tumors and cysts, tibial plateau fractures, avascular necrosis of the femoral head and compression fractures of the spine.[0003]
• U.S. Pat. Nos. 5,108,404 and 4,969,888 to Scholten et al. describe a system for fixing osteoporotic bone using an inflatable balloon which compacts the bone to form a cavity into which bone cement is injected after the balloon is withdrawn. The invention requires the use of fluoroscopy to monitor the injection and to help guard against cement leakage through fissures in bone. Unfortunately, such leakage is known to occur in spite of these precautions. Since such leakage may cause serious injury, including paralysis, an improved device and method is needed.[0004]
• U.S. Pat. No. 5,972,015 to Scribner et al. describes a system of deploying a catheter tube into the interior of a vertebra and expanding a specially configured nonporous balloon therewithin to compact cancellous bone to form a cavity. The Scribner U.S. Pat. No. 5,972,015 approach utilizes a non-porous balloon which is inflated within the bone to cause compression. The cavity thus formed may then be filled with bone cement. Unfortunately, the bag used by Scribner may be ruptured during expansion to compact cancellous bone due to sharp projections found within the cavity to be expanded. Filling the cavity eventually formed could allow leakage of bone cement out of the bone against vessels or nerves which may cause undesirable complications.[0005]
• The present invention involves an improvement of all of the previous techniques and avoids complications that could occur with the system of U.S. Pat. No. 5,972,015.[0006]
• All U.S. patents, applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.[0007]
• The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. § 1.56(a) exists.[0008]
BRIEF SUMMARY OF THE INVENTION
• The invention provides a method of correcting numerous bone abnormalities including bone tumors and cysts, avascular necrosis of the femoral head, tibial plateau fractures and compression fractures of the spine. The abnormality may be corrected by first accessing and boring into the damaged tissue or bone and reaming out the damaged and/or diseased area using any of the presently accepted procedures or the damaged area may be prepared by expanding a bag within the damaged bone to compact cancellous bone. After removal and/or compaction of the damaged tissue the bone must be stabilized.[0009]
• In cases in which the bone is to be compacted, the methods and devices of this invention employ a catheter tube attached to an inflatable porous fabric bag as described in U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich, the disclosures of which are incorporated herein by reference. Those bags may be inflated with less fear of puncture and leakage of the inflation medium than thin walled rubber balloons. They may also be used over a Scribner balloon to protect the balloon from breakage and eventually seepage.[0010]
• The devices of U.S. Pat. Nos. 5,549,679 and 5,571,189 to Kuslich additionally provide the surgeon with the advantage of safely skipping the first balloon inflation steps of Scribner and Scholten, by expanding the bag through introduction of fill material, such as a bone repair medium thereby correcting the bony defect and deformity and stabilizing it in one step of the procedure.[0011]
• As indicated above, the damaged bone may be removed by any conventional reamer. Examples of reamers are described in U.S. Pat. No. 5,015,255; U.S. patent application Ser. No. 09/782,176, to Kuslich et al., entitled Expandable Reamer and filed Feb. 13, 2001; and U.S. patent application Ser. No. 09/827,202 to Peterson et al., entitled Circumferential Resecting Reamer Tool and filed Apr. 5, 2001. Other examples of reamers are know and may be used. After the damaged bone or tissue has been removed, bone repair medium may then be inserted into the cavity thus formed, via a catheter and expandable fabric bag as described in U.S. Pat. Nos. 5,549,679 and 5,571,189.[0012]
• Alternatively, either a smaller than desired cavity may be formed into the bone to be enlarged by compaction or the cavity may be formed only by compaction through introduction of fill material into the bag. In either case, the bag may be positioned over the inflation balloon which is then inflated within the bone site to provide the degree of compaction required. The bag may then be filled with fill material, such as bone repair medium while the balloon remains in place within the bag. Alternatively, the balloon may be removed from the bag prior to filing the bag.[0013]
BRIEF DESCRIPTION OF THE DRAWINGS
• A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:[0014]
• FIG. 1 is a side elevational view of a vertebra that is fractured and in need of repair;[0015]
• FIG. 2 is a side view of the vertebra of FIG. 1 being reamed out with a reaming tool from the anterior approach;[0016]
• FIG. 3 is a top view of the vertebra of FIG. 1 showing the reamer forming a pair of cavities within the vertebra from the anterior approach;[0017]
• FIG. 4 is a side elevational view of the vertebra of FIG. 2 showing placement of an expandable fabric bag of the invention;[0018]
• FIG. 5 is a top elevational view of the vertebra of FIG. 3 showing a second of two expandable fabric bags of the invention being positioned;[0019]
• FIG. 6 is a side view of a vertebra being reamed from a posterior approach;[0020]
• FIG. 7 is a top view of the vertebra of FIG. 6 with a bag in place and a second cavity being reamed;[0021]
• FIG. 8 is a side elevational view of the vertebra of FIG. 6 with an expandable fabric bag of the invention in place;[0022]
• FIG. 9 is a top view of the vertebra of FIG. 7 with one bag inflated and the second bag being deployed;[0023]
• FIG. 10 is a side elevational view showing the vertebra cavity being expanded with an expandable fabric bag about an inflation device in cross-section;[0024]
• FIG. 11 shows the bag system of FIG. 10 with the vertebra in phantom to show the bag system;[0025]
• FIG. 12 is a view similar to FIG. 10 showing a different approach to the interior of the vertebra;[0026]
• FIG. 13 is a view similar to FIG. 11 showing the approach of FIG. 12;[0027]
• FIG. 14 shows the bag of FIG. 12 in a closed, filled and expanded position;[0028]
• FIG. 15 is a top view of the bag system of FIG. 12 being inflated through a catheter tube;[0029]
• FIG. 16 shows a femoral head with avascular necrosis;[0030]
• FIG. 17 shows the femoral head of FIG. 16 being reamed out;[0031]
• FIG. 18 shows placement of a bag system of the invention within the cavity in the femoral head;[0032]
• FIG. 19 is a side elevational view of a tibial plateau fracture;[0033]
• FIG. 20 is a side view of the fracture of FIG. 19 with a cavity being formed with a reamer; and[0034]
• FIG. 21 shows the tibial plateau fracture repaired with an expanded inflatable fabric bag in place.[0035]
DETAILED DESCRIPTION OF THE INVENTION
• In the following detailed description similar reference numerals are used to depict like elements in the various figures.[0036]
• FIG. 1 shows a[0037]typical vertebra10 havingcompression fractures12 that is in need of repair. As indicated above the damaged portion of thevertebra10 may be reamed out compacted or otherwise repaired. For example, FIG. 2 shows areamer14 entering thevertebra10 anteriorly to make anopening15 andcavity16. Alternatively,multiple cavities16 may be formed such as is shown in FIG. 3.
• As previously mentioned, the damaged portion of the[0038]vertebra10 may be compacted in addition to or instead of being reamed out. In FIG. 4 a delivery tube orcatheter20 is seen in the process of delivering anexpandable fabric bag22 into thevertebra10 or into acavity16 present therein. As indicated, thecavity16 may have been created through reaming, compaction by thebag22 or other device, or by other means. Once thebag22 is positioned within thevertebra10, thebag22 may be inflated or expanded to the limits of thecavity16 thus formed through insertion or injection offill material19 into the interior21 of thebag22.
• FIG. 5, shows a single filled[0039]expandable fabric bag22 in place with a second expandable bag which is being inserted and expanded within thecavity16.
• FIGS.[0040]6-9 illustrate a procedure in which theopening15 andcavity16 are created posteriorly. Regardless of the direction through which thevertebra10 is operated on, in all forms, thecavity16 which is formed is then filled with acceptable bone replacement material.
• [0041]Bone replacement material19 may be one or more of the following, or any other biocompatible material judged to have the desired physiologic response:
• A) Demineralized bone material, morselized bone graft, cortical, cancellous, or cortico-cancellous, including autograft, allograft, or xenograft.[0042]
• B) Any bone graft substitute or combination of bone graft substitutes, or combinations of bone graft and bone graft substitutes, or bone inducing substances, including but not limited to: Tricalcium phosphates, Tricalcium sulfates, Tricalcium carbonates, hydroxyapatite, bone morphogenic protein, calcified and/or decalcified bone derivative.[0043]
• C) Bone cements, such as ceramic and polymethylmethacrylate bone cements.[0044]
• The bone replacement material is inserted into the[0045]bag22 via a needle,catheter20 or other type of fill tool. The bone replacement material expands the bag to the limits of thecavity16.
• The[0046]inventive bag22 may be a small fabric bag, about one to about four cm is diameter, being roughly spherical in shape, although other elliptical shapes and other geometric shapes may be used. The bag is pliable and malleable before itsinterior space21 is filled with the contents to be described. The material of thebag22 may be configured to take on the shape of the cavity in which the bag is placed. While in this initial condition, the bag may be passed, uninflated, through a relatively small tube or portal, perhaps about three mm to about one cm in diameter.
• The[0047]bag22 such as may best be seen in FIG. 9, is constructed in a special and novel way. Thebag22 may be constructed of afabric23.Fabric23 may be woven, knitted, braided or form-molded to a density that will allow ingress and egress of fluids and solutions and will allow the ingrowth and through-growth of blood vessels and fibrous tissue and bony trabeculae, but the fabric porosity is tight enough to retain small particles of enclosed material, such as ground up bone graft, or bone graft substitute such as hydroxyapatite or other osteoconductive biocompatible materials known to promote bone formation. Thefabric23 defines a plurality ofpores25. Generally, thepores25 of thefabric23 will have a diameter of about 0.25 mm or less to about 5.0 mm. The size is selected to allow tissue ingrowth while containing the material packed into the bag. If bone cement or other material is used which will not experience bone ingrowth, thepores25 may be much tighter to prevent egress of the media from within thebag22 out into thecavity16. This prevents leakage that could impinge upon nerves, blood vessels or the like if allowed to exit the bone.
• One or more of the[0048]pores25 may be used as afill opening27, wherein thefabric23 may be manipulated to enlarge a pore to a diameter potentially greater than 5 mm but no more than about 1 cm. Preferably thefill opening27 is less than about 5 mm in diameter. Such a pore/fill opening27 is sufficiently large to allow a catheter, needle, fill tube or other device for inserting or injecting fill material to pass through thefabric23 and into the interior21 of thebag22 without damaging the integrity of thebag22.
• When the[0049]bag22 is fully filled with fill material, the bag will form a self-retaining shape which substantially fills thecavity16. Once sufficiently full, the fill tool used to place fill material into thebag interior21 is removed from theopening27. Where theopening27 is not apore25 but rather a separate and distinct opening in thebag22, theopening27 may have a set diameter which requires sealing such as by tying, fastening, welding, gluing or other means of closing theopening27 after the bag has been filed. Where theopening27 is apore25, upon removal of the catheter or fill tool from theopening27 thefabric23 will contract to reduce the diameter of theopening27 to be substantially similar to that of the other pores25.
• The size and density of the pores determine the ease or difficulty with which materials may pass through the mesh. For instance, very small pores (<0.5 mm) would prohibit passage of all but the smallest particles and liquids. The pore size and density could be controlled in the manufacturing process, such that the final product would be matched to the needs of the surgeon. For example, if methylmethacrylate bone cement were to used, the pore size would need to be very small such as about less than 0.5 mm to about 1.0 mm, whereas, when bone graft or biocompatible ceramic granules are used, pore sizes ranging from about 1.0 mm to about 5.0 mm or more may be allowed. The fact that the[0050]fabric16 is properly porous would allow it to restrict potentially dangerous flow of the fill material outside the confines of the bag.
• The fabric is light, biocompatible, flexible and easily handled, and has very good tensile strength, and thus is unlikely to rip or tear during insertion and inflation. When the device is inflated, the device expands to fill a previously excavated[0051]cavity16.
• The use of the term “fabric” herein is meant to include the usual definition of that term and to include any material that functions like a fabric, that is, the “fabric” of the invention must have a plurality of[0052]pores25 through which material and fluid flow is allowed under the terms as described, and the “fabric” must be flexible enough to allow it to be collapsed and inserted into an opening smaller than the inflated bag size.
• The[0053]bag22 need not be woven and may be molded or otherwise formed as is well known in the art. The preferred material may provide the ability to tailor bioabsorbance rates. Any suture-type material used medically may be used to form thebag22. The bag may be formed of plastic or even metal. In at least oneembodiment bag22 is formed using a combination of resorbable and/or nonresorbable thread.Bag22 may include afill opening27 which may be a bushing that could be a bioabsorbable and/or nonbioabsorbable plastic, ceramic or metal. Theopening27 may also be such as hydroxyapatite or it could be plastic or metal. Theopening27 may also be characterized as apore25, wherein apore25 of thefabric23 has been expanded to allow acatheter20 or other fill device to pass into the interior21 of thebag22. Thebag22 could be formed from a solid material to which perforations are added. Thebag22 may be partially or totally absorbable, metal, plastic, woven, solid, film or an extruded balloon.
• In embodiments of the present invention a damaged tissue of a body, such as a[0054]vertebra10 may be treated in accordance with the following procedures such as are depicted in FIGS.1-9:
• Initially, the[0055]vertebra10 needing repair is surgically exposed by forming at least onecavity16. The cavity orcavities16 may be formed by several different means such as by reaming. Reaming may be accomplished by several means such as including the use of areamer14 such as, for example, the Kuslich Expandable Reamer, U.S. Pat. No. 5,015,255, the entire content of which is incorporated herein by reference. Next, the unexpanded mesh bag or Expandable Fabric Bag Device (EFBD)22 is inserted into the cavity or cavities viacatheter20 or other means. At some point, thefill material19 is prepared for insertion or injection into theEFBD22. Following preparation of thefill material19, the material is injected or otherwise inserted into thebag22 using sufficient pressure to fill thebag22 to its expanded state, thus producing rigidity and tension within the cavity orcavities16 to reach the degree of correction required by virtue of the compression fractures. Finally, thefill opening27 is closed to prevent egress ofinflation material19.
• FIGS.[0056]10-15 show a form of the invention in which aballoon30 andcatheter tube32 is employed. Theballoon30 is surrounded by anexpandable fabric bag22 to protect theballoon30 from being punctured during the inflation steps and to remain in place to prevent undesired egress of material injected into the cavity formed in the bone.Balloon30 may be any medical-grade elastomeric balloon. Theballoon30 may be constructed from latex, urethanes, thermoplasic elastomers or other substances suitable for use as an expandable member. Examples of suitable balloons include, but are not limited to: balloons utilized with the FOGARTY® occlusion catheter manufactured by Baxter Healthcare Corporation of Santa Ana, Calif.; balloons of the type described U.S. Pat. No. 5,972,015 to Scribner et al, and others. The methods involve placement of theexpandable fabric bag22 of the invention about theballoon30 of the Scribner et al. device. Theexpandable bag22 is left in place before thecavity16 is filled with bone substitute or bone cement. Theexpandable fabric bag22 prevents breakage of theballoon30 and greatly limits the ability of fill material from leaking out of the cavity through bone fissures where it could cause damage.
• As may best be seen in FIGS. 11, 13 and[0057]15, thebag22 may include aneck29 which extends outwardly from thebag22 to completely overlap the shape ofballoon30. Thebag22 and/orballoon30 may each have a variety of shapes and sizes.
• If desired, the[0058]expandable fabric bag22 may be used as the sole inflation device, eliminating the Scribner et al.balloon30 if the fabric porosity is tight and the inflation media is reasonably viscous.
• While many of the previous embodiments have described the use of the[0059]bag22 for repair of tissue such as a spinal body, in FIGS.16-18 show how thebag22 may be used in treating avascular necrosis of the femoral head. In FIG. 16, afemoral head40 is shown which is in need of repair. FIG. 17 shows the femoral head being reamed out with areamer14, such as previously described. Thereamer14 forms acavity16. In FIG. 18, abag22 is shown within thecavity16 formed within thefemoral head40. Theopening27 of thebag22 is closed off after being filled and expanded with bone substitute material.
• In an alternative embodiment, the Scribner et al. balloon as previously described, may also be used with the[0060]bag22 for repair of thefemoral head40.
• Turning to an embodiment of the invention shown in FIGS.[0061]19-21, atibial plateau48 is shown having afracture50. Thefracture50 is repaired by forming acavity16 with areamer14, such as is shown in FIG. 20. As is shown in FIG. 21, oncecavity16 is properly reamedbag22 may be inserted therein and filled withbone repair media19.
• Other tissue and bone abnormalities may also be treated with the inventive methods and[0062]bag22 described herein. The present invention is not limited to only treatment of spinal bodies, femoral heads, and tibial plateaus. Thebag22 and the methods of treatment described herein, may be utilized through out a mammalian body to treat many types of bone and tissue abnormalities including those described herein as well as others.
• In addition to being directed to the specific combinations of features claimed below, the invention is also directed to embodiments having other combinations of the dependent features claimed below and other combinations of the features described above.[0063]
• The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.[0064]
• Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from[0065]claim1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below (e.g. claim3 may be taken as alternatively dependent from claim2; claim5 may be taken as alternatively dependent on claim3, claim6 may be taken as alternatively dependent from claim3; claim7 may be taken as alternatively dependent from claims3,5 or6; etc.).

Claims (24)

1. A method of treating a bone abnormality in a body comprising the following steps:

exposing an area of bone having an abnormality;

forming at least one cavity in the bone, wherein a portion of the at least one cavity defines an opening;

inserting an expandable, empty fabric bag into the at least one cavity through the opening, the bag being formed of a fabric wall that includes a plurality of bag openings between about 0.25 to about 5.0 mm in diameter, the bag defining an interior and having an exterior;

packing the bag through a fill opening with material that will support or promote bone growth through the fabric wall, the packing causing said bag to expand until the bag and material combination form a self-retaining rigid shape wherein the exterior of the bag is substantially in contact with the bone of the cavity, the plurality of bag openings constructed and arranged to substantially prevent the material from passing from the interior of the bag to the exterior of the bag; and

closing said fill opening to prevent loss of the material from the bag interior.

2. The method ofclaim 1 wherein the bone abnormality is selected from a member of the group consisting of: bone tumors, cysts, avascular necrosis of the femoral head, tibial plateau fractures, compression fractures of the spine and any combination thereof

3. The method ofclaim 1 wherein the area of bone is a vertebra, the vertebra comprising at least one compression fracture.

4. The method ofclaim 1 wherein the area of bone is a femoral head, the femoral head comprising an avascular necrosis.

5. The method ofclaim 1 wherein the area of bone is a tibial plateau, the tibial plateau comprising at least one fracture.

6. The method ofclaim 1 wherein when packing the bag with the material, the fill opening has a diameter of between about 0.25 to about 5.0 mm in diameter.

7. The method ofclaim 1 wherein when packing the bag with the material, the fill opening has a diameter greater than the diameter of the plurality of bag openings, after the bag is packed with fill material the diameter of the fill opening is at least as small as the diameter of the plurality of bag openings.

8. The method ofclaim 7 wherein the fill opening has a diameter of between about 3 mm to about 1 cm.

9. The method ofclaim 1 wherein the fill opening is characterized as self-closing.

10. The method ofclaim 1 wherein formation of the cavity comprises the following steps:

boring into the area of the bone to form the opening;

inserting a reamer tool into the opening; and

excising out a quantity of bone from the area with the reamer tool, the quantity of bone being sufficient to form the cavity.

11. The method ofclaim 1 wherein formation of the cavity comprises the following steps:

boring into the area of the bone to form the opening;

inserting an expandable compaction member into the opening; and

inflating the compaction member thereby compacting a quantity of bone, the quantity of bone being sufficient to form the cavity.

12. The method ofclaim 11 wherein the expandable compaction member is the fabric bag.

13. The method ofclaim 1 further comprising the following steps:

disposing the fabric bag about a body adapted to assume a collapsed geometry for deployment into the bag, the body being expandable to an expanded geometry for compacting cancellous bone; and

expanding the body within the bag, the expansion of the body expanding the bag.

14. The method ofclaim 13 comprising the additional step of:

removing the body from the bag after the body is expanded to the expanded geometry.

15. A method of treating one or more compression fractures in a vertebra comprising the following steps:

exposing an area of the vertebra having the one or more compression fractures;

boring at least one opening into the vertebra;

forming at least one cavity in the vertebra, wherein a portion of the at least one cavity defines the opening;

inserting an expandable, empty fabric bag into the at least one cavity through the opening, the bag being formed of a fabric wall that includes a plurality of bag openings between about 0.25 to about 5.0 mm in diameter, the bag defining an interior and having an exterior;

packing the bag through a fill opening with material that will promote bone growth through the fabric wall, the packing causing said bag to expand until the bag and material combination form a self-retaining rigid shape wherein the exterior of the bag is substantially in contact with vertebral bone of the cavity, the plurality of bag openings constructed and arranged to prevent the material from passing from the interior of the bag to the exterior of the bag; and

closing said fill opening to prevent loss of the material from the bag interior.

16. The method ofclaim 15 wherein the cavity is formed by reaming or compacting cancellous bone of the vertebra.

17. A method of treating avascular necrosis of a femoral head comprising the following steps:

exposing an area of the femoral head having avascular necrosis;

boring at least one opening into the femoral head;

forming at least one cavity in the femoral head, wherein a portion of the at least one cavity defines the opening;

inserting an expandable, empty fabric bag into the at least one cavity through the opening, the bag being formed of a fabric wall that includes a plurality of bag openings between about 0.25 to about 5.0 mm in diameter, the bag defining an interior and having an exterior;

packing the bag through a fill opening with material that will promote bone growth through the fabric wall, the packing causing said bag to expand until the bag and material combination form a self-retaining rigid shape wherein the exterior of the bag is substantially in contact with bone of the cavity in the femoral head, the plurality of bag openings constructed and arranged to prevent the material from passing from the interior of the bag to the exterior of the bag; and

closing said fill opening to prevent loss of the material from the bag interior.

18. The method ofclaim 17 wherein the cavity is formed by reaming or compacting cancellous bone of the femoral head.

19. A method of treating a tibial plateau having one or more fractures, comprising the following steps:

exposing an area of the tibial plateau having one or more fractures;

boring at least one opening into the tibial plateau;

forming at least one cavity in the tibial plateau, wherein a portion of the at least one cavity defines the opening;

inserting an expandable, empty fabric bag into the at least one cavity through the opening, the bag being formed of a fabric wall that includes a plurality of bag openings between about 0.25 to about 5.0 mm in diameter, the bag defining an interior and having an exterior;

packing the bag through a fill opening with material that will promote bone growth through the fabric wall, the packing causing said bag to expand until the bag and material combination form a self-retaining rigid shape wherein the exterior of the bag is substantially in contact with bone of the cavity within the tibial plateau, the plurality of bag openings constructed and arranged to prevent the material from passing from the interior of the bag to the exterior of the bag; and

closing said fill opening to prevent loss of the material from the bag interior.

20. The method ofclaim 19 wherein the cavity is formed by reaming or compacting cancellous bone of the tibial plateau.

21. A device for compacting cancellous bone comprising:

an inner layer and an outer layer, the outer layer defining a flexible material which at least partially surrounds the inner layer, the inner layer defining an elastomeric body, the outer layer including a plurality of pores which extend therethrough, the inner layer and outer layer combination define an expandable body adapted to assume a collapsed geometry for deployment into bone and an expanded geometry for compacting cancellous bone to form a cavity, the inner layer defining a substantially hollow chamber, the inner layer and outer layer defining at least one opening, the expandable body constructed and arranged to expand from the collapsed geometry to the expanded geometry when a predetermined amount of fill material is placed within the substantially hollow chamber through the at least one opening, the outer layer constructed and arranged to prevent penetration of the inner layer by the cancellous bone encountered during expansion of the expandable body.

22. The device ofclaim 21 wherein the inner layer is a medical balloon.

23. The device ofclaim 22 wherein the medical balloon is at least partially constructed from at least one member of the group consisting of: latex, thermoplastic elastomers, urethanes, and any combination thereof.

24. The device ofclaim 21 wherein the outer layer is an expandable mesh bag.

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