BRPI0607904A2 - device for containing material inside bone - Google Patents

Abstract

DEVICE FOR CONTAINING MATERIAL INSIDE BONE. The present invention relates to a resorptive containment device for use in treating bone voids and restoring the diseased or fractured anatomy. The resorptive containment device may be a balloon of varying size or shape to conform to the bone to be treated and may be employed on any type of bone in which collapsed cork bone fractures may be treated by restoring bone from its surface. internal. The containment device may be formed of a pluronie-based polymer and may degrade in vivo within weeks of implantation into the bone. The balloon may be multilayered to provide desired surface characteristics, puncture and tear resistance, or other beneficial properties as appropriate to the particular application of the device.

Description

"DEVICE FOR CONTAINING MATERIAL IN BONE, AND METHOD FOR FORMING A RESORVABLE CONTAINMENT DEVICE"

Cross Reference to Related Applications

This is a continuing portion of US patent application US10 / 636.549, filed August 8, 2003, which also claims the benefit, under US $ 35, of US patent application 09 / 908,899, filed July 20. US Patent No. 6,632,235 B2, which claims benefit under 35 US $ 119 (e) of provisional application 60 / 284,510 filed April 19, 2001. All of the foregoing documents are incorporated herein by reference. Field of the Invention

The present invention relates to a bone void containment device, a process for the manufacture of a bone void containment device and a method for use in orthopedic procedures for the treatment of bones and in particular for an improved device and method for fracture reduction and treatment of the spine. Background of the Invention

Medical balloons are commonly known to dilate and unblock the heart-feeding arteries (translumenal percutaneous coronary angioplasty) and other than coronary arteries (translumenal percutaneous non-coronary angioplasty). In angioplasty the balloon is wrapped tightly around a catheter shaft to minimize its profile and is inserted through the skin into the narrowed section of the artery. The balloon is typically inflated by a saline or radiopaque solution that is forced into the balloon through a syringe. Alternatively, for retraction, vacuum is applied to the balloon to empty it.

Medical balloons have also been used to treat bone fractures. A device for this purpose is disclosed in Berger U.S. Patent 5,423,850, which teaches a method and assembly for positioning a fractured tubular bone using a balloon catheter. The balloon is inserted away from the fracture site by an incision in the bone, and guidewires are used to transport the uninflated balloon through the medullary canal in addition to the fracture for positioning. The uninflated balloon is held securely in place by the positive pressure applied to the intramedullary walls of the bone. Once the balloon is positioned, the catheter tube attached to it is pulled with a calibrated force measuring device. Tightening the catheter with the balloon in place aligns the fracture and compresses together the proximal and distal portions of the fractured bone. The traction catheter is then attached to the bone at the insertion site by a screw or similar fixation device.

As one skilled in the art will readily confirm, there is a continuing need for new and innovative medical balloons and balloon catheters, and in particular a need for balloon catheter equipment to treat diseased and damaged bones. More specifically, there is a need for a low-profile, high-pressure, puncture, and tear-resistant medical balloon that can be used to restore the natural anatomy of a damaged cortical bone.

Summary of the Invention

The present invention relates to a device for containing material within the bone. The device may include a barrier member configured and adapted for insertion into bone, the barrier member having inner and outer surfaces defining an inner surface. The barrier member must be capable of preventing fluid within the space from passing through the inner surface to the outer surface. The barrier member may comprise a caprolactone-based polyurethane polymer, said barrier member being capable of degrading in vivo into biologically compatible substances. The barrier member may include a plurality of polymer layers. Additionally, the barrier member may comprise a caprolactone and Pluronic based polyurethane polymer. The barrier member should have a tensile strength between about 15 and about 50 MPa. For example, the barrier member may have a tensile strength between about 25 and about 35 MPa. The barrier member may have a Young's modulus between about 5 and 30.

In an exemplary embodiment the barrier member may have a Young modulus between about 15 and 25. The barrier member may have a rupture length between about 600 and 100. For example, the barrier member may have an elongation at rupture between about 850 and 950. The barrier member may have an average molecular weight between about 100,000 and 200,000 Dalton. For example, the barrier member may have an average molecular weight between about 150,000 and 190,000 Dalton. The mass may deteriorate in vivo after the device is implanted into bone or another part of the body. In an illustrative embodiment more than about 60% of the mass degrades in vivo after about 16 weeks of degradation. The mass may degrade in vivo to produce carbon dioxide, water and diamine. In a non-limiting example, the barrier member may be about 0.3 mm thick.

The present invention is also directed to methods of treating bone voids. One method may include access to a cavity in the bone where the cavity has one or more limiting surfaces and may contain organic material. The cavity should then be prepared to be substantially clean of organic material. The boundary surfaces of the cavity should be sprayed with a sealing spray prior to filling the cavity with a loader material. The method may also include cavity irrigation of the boundary surfaces for removal of organic material and porous bone. Cavity irrigation can also wash off limiting surfaces. The cavity may be aspirated to remove liquids and solid materials from the cavity and boundary surfaces. The method may include positioning a solid barrier formed of biologically resorbable material on the boundary surfaces and placing a liquid bone carrier against the barrier to fill the cavity. The method may also include preventing the transport of foreign matter from the cavity. This may involve obstructing openings in the limiting surfaces and obstructing voids in the porous bones. The method may also include blocking vascular passages on the cavity boundary surfaces. The method may also include obstruction of cracks in the cortical bone, where the cracks may extend to the cortical bone. The method may also use an instrument for placing seal on the boundary surfaces of the cavity. The method may also include carrier of liquid bone-containing material into the solid barrier member to form a containment device. The containment device may be filled with bone material from the magazine. The containment device may be loaded with bone loader bone material to substantially fill the cavity. The method may also comprise allowing the boot bone matter to heal. The containment device may be implanted within the bone. Spatial interrelationships between the containment device and the cavity can be interpreted by fluoroscopic imaging. One or more containment devices may be implanted within the bone. Improvement in the quality of fluoroscopic imaging can be achieved by allocating a distinctive radiographic signature to each retaining device implanted within the bone. Brief Description of the Drawings

Preferred features of the present invention are shown in the accompanying drawings, where similar reference characters designate similar elements in the various views, where: Fig. 1 shows a perspective view of a medical balloon catheter system according to the present invention.

Fig. 2 shows a perspective view of the balloon of Fig. 1.

Fig. 3 shows a side view of a balloon of the present invention.

Fig. 4 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 5 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 6 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 7 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 8 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 9 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 10 shows a sectional view perpendicular to the longitudinal axis of the balloon of Fig. 9.

Fig. 11 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 12 shows a sectional view perpendicular to the longitudinal axis of the balloon of Fig. 11.

Fig. 13 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 14 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 15 shows a top view of another embodiment of the balloon of Fig. 1.Fig. 16 shows a top view of another embodiment of the balloon of Fig. 1.

Fig. 17 shows a plan view of the catheter of Fig. 13.

Fig. 18 shows a plan view of a reinforcement insert for the catheter of Fig. 17.

Fig. 19 shows an enlarged sectional view along line 19-19 of Fig. 18.

Fig. 20 shows an enlarged sectional view along line 19 - 19 of another embodiment of the reinforcement insert of Fig. 18.

Fig. 21 shows an enlarged sectional view along line 19-19 of another embodiment of the reinforcement insert of Fig. 18.

Fig. 22 shows an enlarged sectional view along line 19-19 of another embodiment of the reinforcement insert of Fig. 18.

Fig. 23 shows an enlarged sectional view along line 19-19 of another embodiment of the reinforcement insert of Fig. 18.

Fig. 24 shows an enlarged sectional view along line 19-19 of another embodiment of the reinforcement insert of Fig. 18.

Fig. 25 shows a perspective view of an exemplary embodiment of a reinforcement insert for the catheter of Fig. 17.

Fig. 26 shows a partial sectional view along the longitudinal axis of another embodiment of the balloon catheter of Fig. 1.

Fig. 27 shows a sectional view through line 27 - 27 of Fig. 26.

Fig. 28 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 29 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 30 shows an intermediate perspective view of another embodiment of the balloon of Fig. 1.Fig. 31 shows a partial sectional view along the longitudinal axis of the fully constructed balloon of Fig. 30.

Fig. 32 shows a schematic representation of the balloon catheter construction of Fig. 30.

Fig.33 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 34 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 35 shows a perspective view of another embodiment of the balloon of Fig. 1.

Fig. 36 shows a plan view of another embodiment of the balloon catheter of Fig. 1.

Fig. 37 shows a sectional view through the line 37 - 37 of Fig. 36.

Fig. 38 shows a perspective view of an exemplary embodiment of a resorbable containment device.

Fig. 39 shows a perspective view of a mandrel for forming the resorbable holding device of Fig. 38.

Fig. 40 shows a perspective view of one embodiment of the resorbable holding device of Fig. 38 with a filament.

Fig. 41 shows a perspective view of another embodiment of the resorbable holding device of Fig. 38 with a filament.

Fig. 42 shows a perspective view of an exemplary embodiment of a filament for use with the mandrel of Fig. 39 in forming a resorbable holding device.

Fig. 43 shows a perspective view of another embodiment of a filament for use with the mandrel of Fig. 39 in forming a resorbable holding device.

Detailed Descriptions of Preferred Embodiments

In the following descriptions any reference or orientation or direction is to be understood primarily as a convenience of description and is not intended in any way to limit the scope of the present invention.

Fig. 1 shows an apparatus 10 for use in reducing fractured bones according to the method of the present invention. Apparatus 10 comprises an inflatable device 15, a connector y 20, catheter shaft 25, balloon 30, and hub cavity 35. As shown in Fig. 1 balloon 10 is shown at the distal end of catheter shaft 25 prior to positioning. . The instruments illustrated in Fig. 1 are representative of tools and other devices that may be used in conjunction with the balloon. These tools, however, may not always be necessary or may be exchanged for different devices that perform similar, additional or different functions. For example, one of ordinary skill in the art would like the y-connector to be interchangeable with a wide variety of other suitable devices.

Balloon 30 may be used to treat any bone with a sufficiently large inner cavity sufficient to receive balloon 30. Nonlimiting examples of bones that are suitable candidates for anatomical restoration using the device and method of the present invention include vertebral bodies, canals bone marrow, calcaneal and tibial plateau. The balloon 30 may be designed and adapted to accommodate particular bone anatomies and different cavity shapes that may be made in these and other appropriate large bones.

Additionally, the balloon may be designed and configured to be positioned and remain in the bone cavity for an extended period of time. For example, the balloon may be inflated with natural or synthetic bone-carrying material or other appropriate inflation fluid once the balloon is located within the bone cavity. Once filled, the balloon is allowed to remain inside the bone for a prescribed period or perhaps indefinitely. The length of time the balloon stays within the bone may depend on specific conditions of the treated bone or the particular goal pursued by the treatment. For example, the balloon may remain within the cavity for less than one day, for several days, weeks, months or years or may remain permanently within the bone. As will be explained in more detail below, the balloon may also be adapted to serve as a prosthetic device outside a specific bone cavity such as between two adjacent vertebrae.

Additionally, the outer surface of the balloon may be treated with a coating or texture to help the balloon become more integrated with neighboring bone matter or to facilitate patient acceptance of the balloon. The choice of balloon materials, coatings and textures can also help prevent body rejection of the balloon. Similarly, the inner surface of the balloon may be textured or coated to improve balloon performance. For example, the inner surface of the balloon may be textured to increase adhesion between the balloon wall and the material within.

In another embodiment, the balloon may be designed to rupture, tear or otherwise open after the injected carrier material within the balloon has fixed or sufficiently geled, cured or solidified. The balloon can then be removed from the bone by leaving the charger material inside it. This approach may result in a more controlled positioning of the bone loader in the bone. This can be particularly beneficial where leakage of bone material from the loader out of damaged cortical bone may be a problem although other situations may occur where this configuration is also beneficial.

Alternatively, the balloon may be opened or ruptured to allow the carrier matter to let inflation fluid be released into the cavity. For example, the opening of the balloon may be predetermined such that the flow of the carrier matter flows in a desired direction. Further, the carrier matter can be held within the balloon until it is partially fixed so that breaking the balloon, the higher viscosity of the carrier matter limits the extent to which the carrier matter will travel.

The balloon can also be designed and configured to release inflation fluid into the cavity in a more controlled manner. For example, the balloon catheter may be provided with a mechanism for initiating the rupture process in a highly controlled manner. In one embodiment, predetermined seams in the balloon may immediately open and erupt at certain pressures. In another embodiment the seams may open only after prolonged exposure to a particular pressure, temperature or material.

One skilled in the art would appreciate any of the various ways of opening or breaking the balloon without departing from the spirit and scope of the present invention. For example, at least a portion of the balloon may be dissolved until the carrier matter is released into the bone cavity. In another example the balloon may rupture and be innocuously incorporated into the medium of the inflation fluid. In yet another example, the carrier matter may be designed to solidify upon contact with a chemical treatment applied to the balloon surface. In yet another embodiment, two balloons (or a single two-chambered balloon) may be designed and configured to release a combination of fluids which when mixed together react to form a carrier of inert material within the cavity. In another embodiment different areas of the seam or balloon may be designed to rupture at different predetermined pressures or at different times.

In addition, the balloon can be designed to open in many ways. For example, a surgeon may dissolve the balloon once the desired conditions for the bone material of the carrier have been achieved. A balloon adapted to rupture and release inflation fluid for direct contact with the cavity can also be designed and configured to tear along predetermined seams. The seams should run parallel to the longitudinal axis of the balloon and remain secure in the catheter at the distal end of the balloon, resembling an open banana peel. In another embodiment the predetermined seams may consist of a single spiral seam originating at the distal end of the balloon and ending at the distal end of the balloon resembling the peel of a peeled orange.

Other balloon adaptations may be provided to dissolve the balloon in a controlled manner. For example, the balloon may be constructed with fault zones adapted so that structural failures under a triggering condition may preferably occur in a localized area. For example, a balloon may have a failure zone comprising a thinner membrane. In another example the balloon may be designed to have no elastic reinforcing elements in a given region. In yet another example a balloon region may be made of a material that would collapse due to a chemical reaction. For example, the chemical reaction may be an oxidation or reduction reaction where the material may sacrificially neutralize a weak acid or base. In another example, the sacrificial region may comprise a pore type region model. The sacrificial region may comprise a specific model of pores that would form a latent perforation in the balloon membrane or which could be randomly distributed in a localized area. The ruptured balloon may then be removed from the bone cavity leaving behind the bone material of the balloon. To facilitate the removal of the ruptured balloon from the bone cavity, the balloon may be treated with chemical coatings or special substances, or may be textured to prevent the balloon from sticking to the loader material or cavity walls. In one embodiment the balloon may open at the distal end. This configuration may allow the balloon to be more easily removed from the bone cavity after the balloon has been opened or ruptured.

In addition, biologically resorbable balloons may be designed and configured in accordance with the present invention. For example, a positioned balloon comprising bio-resorbable polymers can be transformed by physiological conditions into harmless substances that are biologically compatible or naturally occurring in the body. These substances may remain in the patient or be expelled from the body via metabolic activity. In one example, a balloon designed to restore the anatomy of a vertebral body would be placed within a cavity prepared within the vertebra to be treated and inflated with a radiopaque material from the carrier. Immediately after inflation (or after the carrier material has been partially fixed) the balloon may be released, detached or detached from the catheter to remain within the bone. While the balloon is resorbed new bone can replace the matter of the charger. Alternatively, the carrier material may be converted by biological activity to bone or simply remain in bone.

As one skilled in the art will readily appreciate, a positioned balloon may be designed for partial or complete resorption. For example, a selectively resorbable balloon may be configured to produce a bio-inert implant, structure or configuration comprising a plurality of such things. For example, a balloon may have a resorbable component membrane and a biologically-structurally reinforcing component. In another example, a balloon designed to be selectively resorbed may form a series of bio-inert segments. These bio-inert segments may provide structural containment or reinforced interfaces at weakened positions of the cortical bone. The segments may also be designed to cooperate and beneficially dissipate postoperative stresses generated at the interface between the restored cortical bone and the loader material. The precise nature of this strain reduction can be adapted to a particular anatomy.

An implanted balloon can also be designed so that it can be reabsorbed only after certain conditions are met. For example, a balloon designed to contain in a particular region of unhealthy or damaged cortical bone may eventually be reabsorbed following one or more of the triggering conditions. In one example, the return of normal psychological conditions could trigger the decomposition of the implanted balloon. The triggering condition may involve conditions of relative temperature, pH, alkalinity, redox potential and osmotic pressure between the balloon and the surrounding bone or porous matter.

In another example a controlled chemical or radiological exposure could trigger the balloon decomposition. For example, a chemically triggered resorption may include, but is not limited to, a drug prescribed by a physician, a chemist specially developed to be delivered to the balloon via oral ingestion or intravenous injection. A discharge or electric current, exposure to high frequency sound or X-rays can also be used to trigger the biological resorption of the balloon.

Resorbable balloons may also provide an implanted balloon with beneficial nonstructural properties. For example, soluble compounds contained in a bio-resorbable capsule may offer certain clinical benefits. For example, a resorbable balloon may decompose when healthy porous bones remain in contact with the balloon for about six weeks. The decomposition of the balloon may then expose a medicament placed within the balloon structure as an inner lining. The drug may also be incorporated into the balloon matrix itself to provide a temporal release function for drug release. The medicament may promote further bone growth in general or in a particular area. Examples of other complementary benefits include, but are not limited to, antibacterial effects that prevent infections and agents that promote muscle, nerve or cartilaginous regeneration.

In use, the balloon 30 is inserted into the bone cavity that has been prepared to allow the balloon to be placed near the damaged cortical bone. Preferably the porous tissue and bone marrow within the bone and the area to be treated should be removed from the region prior to positioning the balloon. Clearing of the region to be treated may be accomplished either by dislocation or relocation of the porous bone and marrow to regions within the bone that will not be treated or, alternatively, by removing such materials from the bone. Alternatively, porous bone and marrow may be removed with a countersink or any other device.

Additionally the bone cavity may be irrigated and / or aspirated. Preferably aspiration should be sufficient to remove the bone marrow from within the region to be restored. In particular, a region as large as the entire balloon to be positioned should be aspirated in this manner. More preferably, the region to be aspirated should exceed the length of the entire balloon to be positioned by about 2 mm to 4 mm. Cleaning the cavity of substantially all bone marrow near or within the region to be treated may prove particularly useful for bone restoration and balloon incorporation as a prosthetic device to remain in the cavity.

Substantial cleaning of the entire bone marrow from the area to be treated can also provide better implant synthesis with cortical bone and prevent uncontrolled displacement of bone marrow out of damaged areas of cortical bone. For example, a balloon for restoration of a vertebral body may also comprise a prosthetic implant that will remain in the restored vertebra for an extended period of time. Substantial removal of the entire bone marrow from the vertebra region to be restored may provide a better contact surface between the bone to be restored and the implant.

For example, removing substantially all bone marrow from the treated bone region may reduce the potential for inadvertent and systemic damage caused by embolization of materials released into the vascular system. For vertebral bodies, removing the bone marrow may also reduce the potential for spinal cord damage from uncontrolled displacement during balloon placement or subsequent compression of the vertebrae and implant mass.

In addition, the cavity may be treated with a seal to help prevent or reduce the leakage of carrier material from the cavity or to help prevent bone materials or percolating body fluids into the cavity. Generally, sealants comprising fibrin or other suitable natural or synthetic constituents may be used for this purpose. The sealant may be applied at any suitable time or mode, such as spraying, irrigation, flushing, topical application. For example, the seal may be spray coated into the cavity before or after the balloon arrangement. In addition, the seal may be applied to the outer balloon as a coating such that the seal is dispatched to the cavity as the balloon is disposed.

In another example, the seal may be placed first within the treated area, and then an inflatable device may be used to push the seal out toward the cavity walls. The inflatable device may be rotated or axially moved to apply the seal. In addition, the balloon may not be fully pressurized or may be gradually pressurized while the sealant is being applied.

The viscosity or other properties of the seal may be varied according to the type of shipment and the procedure used. For example, it is preferred that the sealant be a gel if it is placed within the cavity and the balloon is used to apply it to the cavity walls. As described above, each of these optional steps with respect to the use of a seal may be performed after balloon inflation or before or at all.

Thereafter, the balloon 30 is inserted into the prepared cavity, where it is inflated by fluid (eg, saline or radiopaque) under precise pressure control. Preferably, the balloon 30 is inflated directly against the cortical bone to be restored via the inflation device 15. Thus, the arranged balloon presses the damaged cortical bone to a configuration that reduces fractures and restores the anatomy of the damaged cortical bone. .

Following fracture reduction, the balloon is deflated releasing the inflation pressure from the device. Preferably, the balloon may be further collapsed by applying negative pressure to the balloon by use of a suction syringe. The suction syringe may be the inflation device itself, or an additional syringe, or any other device suitable for deflating the balloon. After the balloon is sufficiently deflated, the balloon may be removed from the cavity, and the bone cavity may be irrigated or aspirated. Optionally, the cavity may also be seal-treated. The cavity can then be filled with bone carrier material. The bone carrier material may be natural or synthetic bone carrier material or any other bone cement. As described above, each of these optional steps can be performed after balloon inflation, or before or at all.

As more fully described below, the timing of balloon deflation and cavity filling with bone carrier material may be varied. In addition, the balloon may not be deflated before completing the surgical procedure. Instead, it may remain within the bone cavity for an extended period. Thus, the method of the present invention relates to creating a porous bone cavity, reducing fractures to the damaged cortical bone with a medical balloon, restoring the natural anatomy of the damaged bone, and filling the restored bone structure with carrier material.

The inflatable device may also be adapted to serve as a prosthetic device outside the bone. An example is that the balloon can be used as an artificial disc located between two adjacent vertebrae. Use of an inflatable device in this manner may allow replacement of the treated disk cores, or alternatively may be used for complete replacement of the treated disk. Portions of the treated disc may be removed prior to disposal of the inflatable device. The amount of disc material removed may depend on the condition of the treated disc and the degree to which the treated disc will be replaced or supported by the inflatable device. The treated disc can be entirely removed, for example when the inflatable device serves as a complete disc replacement. If the inflatable device is to support or replace the core or other portion of the treated disc, then less material, if any, may need to be removed prior to disposal.

The construction and shape of the inflatable device may vary according to its intended use with either a full disc replacement or a nuclear replacement. For example, an inflatable device intended to completely replace a treated disc may have a thinner balloon membrane or have coatings or other treatments that accurately replicate the anatomical structure of a natural disc. Some features include linings or textures on the outer surface of the inflatable device that help anchor or stick it to the vertebral end plates that interface with the artificial disc. The balloon membrane can also be configured to replicate the stiffness, mechanical behavior, and ring anatomy of a natural disc. The carrier material, similarly, may be tailored to have a mechanical behavior similar to that of a natural disk.

In another example, if the inflatable device is intended to treat only the disk core, the balloon may be designed with a thin wall membrane that conforms to the interior of the natural disk structures that remain intact. In addition, the balloon membrane may be resorbable so that the carrier material remains after the inflatable device has been disposed. Alternatively, the balloon membrane may be designed and configured to allow the balloon to be dissolved and removed from the patient during surgery. An advantage of this design would be that the balloon can function as a dispatching device that allows for the interoperable measurement of the volume of carrier material introduced into the patient. In addition, this design allows for interoperable volume adjustment so that loading material can be added or removed according to the patient's anatomy prior to permanent disposal. Other design features of the inflatable device and loading material described herein for other embodiments or uses may also be utilized when designing a balloon as an artificial disk.

In one embodiment of an artificial disc, the balloon is inflated with a radiopaque material to restore the natural spacing and alignment of the vertebrae. The inflation solution or material may be cured to form a viscous, elastic, deformable solid. Preferably, such a balloon may comprise implant processing material and mechanical properties that approximate a natural and healthy disc. For example, the balloon may be designed for long-term resistance to puncture and breakage damage, and the carrier material may be designed and configured to provide flexible, elastic, or fluid properties. Generally, the carrier material for a replacement disc balloon may comprise any suitable substance, including synthetic and biodegradable polymers, hydrogels, and elastomers. For example, a balloon may be partially filled with a hydrogel that is capable of absorbing large volumes of liquid and withstanding reversible swelling. A hydrogel filled balloon may also have a porous or selectively porous containment membrane that allows fluid to move in and out of the balloon as it is compressed or expanded. The carrier material may also be designed and configured to form a composite structure comprising a solid mass of materials.

Balloons of the present invention may also be adapted for use as a diversion instrument and an implant for intercorporeal fusion, such as for the lumbar and cervical regions. For example, an inflatable device of the present invention may be used for posterior lumbar interbody fusion (PLIF). A laminotomy, for example, may be performed to expose a window to the operating site comprising a disk space. The disc and superficial layers of the adjacent cartilaginous endplates can then be removed to expose the bleeding bone in preparation for receiving a pair of PLIF spacers. A balloon of the present invention may then be inserted into the disk space and inflated to deflect the vertebra. Controlled balloon inflation can ensure optimal vertebra deviation and facilitate maximum implant height and neural foraminal decompression. Fluoroscopy and a weak radiopaque inflation fluid can assist in determining when a segment is completely deviated.

If the balloon serves as a deflection instrument, a bone or synthetic allograft together with the porous bone graft or carrier material can then be implanted within the contralateral disc space. Once the implant and other materials are in the desired position, the balloon can be deflated and removed from the disk space and a second implant of the same height can be inserted into that space.

If the balloon serves as a spacer for intervertebral body fusion, the balloon may be inflated with a carrier material that adjusts to form a synthetic allograft implant in vivo. Once the implant has been properly formed, the balloon can be dissolved and removed from disk space. In another example, the inflated balloon is left intact and is separated from the catheter to remain within the disk space as a scaffold for new bone growth. As previously described, a balloon implant can also be resorbed by physiological conditions and expelled from the patient or transformed and reshaped for new bone growth.

For techniques involving multiple balloon arrangements or carrier material, different radiographic signatures may be used for each arrangement to enhance the quality of fluoroscopic imaging and to assist the surgeon in interpreting spatial relationships within the operating site. The use of different radiographic signatures can be used, for example, with inflatable devices when they are used as instruments (such as a bone restoration tool or as a diversion device), when they are used to dispatch bone carrier material, or when they are used as implants. Additionally, the use of different radiographic signatures may be used for multiple arrangements or loading materials. For example, a technique involving the arrangement of two balloons between adjacent vertebrae could benefit from this approach. Similarly, other orthopedic procedures, such as vertebroplasty, may also involve the arrangement of multiple balloons having different radiographic signatures. In another example, when the balloon of the present invention is used as a PLIF spacer, the loading material within the first of the two intervertebral spacer implant balloons may be provided with less radiopacity than the second implant. As one skilled in the art would readily appreciate, varying the radiopacity of the respective implants would facilitate fluoroscopic monitoring and second implant placement. In particular, this would prevent an implant disposed on a first side from blocking the fluoroscopic image of a second implant. This advantage can also be realized when different radiographic signatures are used in any situation involving multiple arrays, such as for multiple arrays of balloons or carrier materials as described above.

The radiopacity of each implant can be varied by incorporating different concentrations of a radiopaque material into the balloon-inflating carrier material. For example, filler materials comprising two different concentrations of barium sulfate may be used. Similarly, different radiopaque materials having distinguishable fluoroscopic characteristics may be used.

Fig. 2 shows a medical balloon 40 of the construction described above inflated at approximately 1,378958MPa. Preferably, balloon 40 is made from a unitary layer of polyurethane material. Multiple balloon layers and coatings of other materials such as silicone may also be used. For example, the silky texture of an outer layer, or silicone coating, may be used to facilitate balloon insertion 40 or to achieve another clinical purpose. One of ordinary skill in the art would recognize that additional materials, layers and coatings and combinations thereof can be used to enhance the usefulness of balloon 40, for example, by increasing the capacity of the inflated vessel to resist puncture and tearing. Preferably, the unit wall thickness of balloon 40 may range from approximately about 1.5 mils (45.72 cm) to about 2.5 mils (76.2 cm). A unitary wall thickness, however, ranging from about 0.5 mils (15.24 cm) to about 3.5 mils (106.68 cm) may also be preferred for particular applications. The thickness of the optional layers or coatings may preferably range from approximately about 0 mils (0 cm) to about 4 mils (121.92 cm). Additionally, radiopaque indices (not shown) may be applied to the outer surface of balloon 40 to provide an enhanced visual means for estimating the degree of inflation and collapse.

A composite balloon comprising at least two materials which may serve as a reinforcing component and as a boundary forming component. The boundary forming component may be any suitable material used to form a balloon. Examples of such materials are more fully described herein. The reinforcing member may provide additional tensile strength to the balloon by collecting the tensile strength normally applied to the balloon boundary forming component. The reinforcing member may be designed and configured to distribute these forces equally about its structure, or may be designed and configured to form a spatial frame for the arranged balloon structure. The reinforcing member can facilitate better shape control for the balloon and provide a thinner boundary forming member.

In one embodiment, the reinforcing member member may be an interlaced matrix extending over selected areas of the balloon. In another embodiment, the interlaced matrix may encompass the balloon structure in its entirety. In another embodiment, the interlaced matrix is on the inside of the balloon boundary forming component. Conversely, in another embodiment, the interlaced matrix is located on the outside of the balloon boundary forming component. In one embodiment, the interlaced matrix is located within the boundary forming component. For example, a boundary forming component comprising a membrane could include an interlaced matrix within the membrane. The reinforcement strength of the interlaced matrix may be influenced by the type of material from which it is constructed, or by the shape and size of the individually interlaced reinforcement members.

Additionally, the reinforcing strength of the interlaced matrix can be determined by the tension of the weave. For example, a denser pattern for the interlaced matrix could provide greater strength but less flexibility than a less dense weave of a similar pattern. Also, different patterns may have different combinations of physical characteristics. The angle of intersecting interlocking limbs can also be varied to optimize the physical properties of the balloon. The interlaced matrix can therefore be customized to provide a certain combination of physical or chemical properties. These properties may include tensile and compressive strength, puncture resistance, chemical inertia, shape control, elasticity, flexibility, collapse ability, and the ability to maintain high levels of long-term performance. Interlaced materials may be comprised of any suitable material including nitinol, polyethylene, polyurethane, nylon, natural fibers (e.g. cotton), or synthetic fibers. One company that manufactures interlaced arrays of the type described above is Zynergy Core Technology.

As noted above, the fronting member may comprise a synthetic membrane formed of polyurethane or other materials as described for the general balloon construction. The membrane may be coated over the exterior to enhance non-reactive properties between the balloon and the body, or to ensure that a balloon will not stick to balloon inflation materials. In this way, a dissolved balloon can be removed without significant disturbance to the filled cavity. It is expected that a balloon formed of an interlaced membrane and matrix can be designed to operate at an internal pressure of about 2.068437MPa.

As previously described, the size and configuration of the inflation device may vary according to the particular bone to be restored. Fig. 3 illustrates a general construction of a balloon of the present invention. Features described in Fig. 3 include: D1 (the outer diameter of the balloon tubing); D2 (the outer diameter of the balloon working body); LI (the length of the balloon); L2 (the working length of balloon 70); a (the tapered angle of the proximal end of the balloon); and P (the angle of the distal end of the balloon). Angles a and f3 are measured from the longitudinal axis 80 of the balloon. Table 1 presents preferred values for the characteristics of the balloon construct illustrated in Fig. 3, as they may apply to particular bone anatomies. The values given in variation 1 represent generally preferred dimensions and characteristics. The values presented in variation 2, by comparison, represent more preferred criteria.

TABLE 1

PREFERRED AXIAL BALLOON MODES

<table> table see original document page 25 </column> </row> <table> As described in Table 1, a preferred balloon for a vertebral body would have tubing 60 with an outer diameter D1 ranging from about 1.5mm to about 3.0mm. Tubing 60 would also preferably be suitable for attachment to a 16 gauge catheter. As best shown in Fig. 3, balloon tip 65 can be sized to catheter requirements. Additionally, the outer diameter D2 would preferably range from about 8mm to about 26mm, and more preferably from about 12mm to about 20mm. Similarly, the proximal end 75 of balloon 70 may taper at an approximately uniform angle from the longitudinal axis 80 of balloon 70. Preferably, the angle a ranges from about 25 degrees to about 80 degrees, and more. preferably it ranges from about 45 to 60 degrees. The distal end 85 of the balloon 70 may also taper at an approximately uniform angle p from the longitudinal axis 80 of the balloon 70. Preferably, the angle p ranges from about 90 degrees to about 50 degrees, and more preferably. from about 60 to 86. In addition, the length L1 of the balloon 70 preferably ranges from about 15mm to about 30mm, and the working length L2 of the balloon 70 preferably ranges from about 15mm to about 30mm. 10mm to about 20mm. More preferably, however, the length L1 of balloon 70 ranges from about 20mm to 25mm, and the working length L2 of balloon 70 ranges from about 12mm to about 15mm.

Preferred embodiments described above include preferred balloon sizes and shapes comprising an interlaced matrix and membrane. As noted earlier, this balloon can be adapted to remain with a vertebral body, such as a prosthetic device or implant.

Figs. 4-6 show preferred embodiments of the axial balloon 70 described in Fig. 3 and Table 1. While the following discussion is directed to examples of balloon embodiments for vertebral body placement, such balloons may be used on any suitable bone. Thus, the dimensions and configurations of the balloon styles described in these figures may be varied to accommodate the type of bone or cavity in which the balloon is to be disposed.

Fig. 4 illustrates a style of uniform balloon design 90 having an axially uniform diameter D3 with a blunt distal end 95. In one embodiment, the total length L3 is about 20mm, the length of Working L4 is about 15mm, and the outside diameter D3 is about 12mm. In another embodiment, the total length L3 is about 20mm, the working length L4 is about 15mm, and the outside diameter D3 is about 8mm. In yet another embodiment, the total length L3 is about 15mm, the working length L4 is about 10mm, and the outside diameter D3 is about 8mm.

Fig. 5 illustrates a style of balloon embodiment with a central protrusion 100 having a constant outer diameter D4 in a central portion of the balloon 70, while having uniformly tapered ends 105. In one embodiment, a balloon with a protrusion The center piece has an overall L5 length of about 20mm, an L6 working length of about 8mm, a horizontal tapered distal end length L7 of about 5mm, and a total outer diameter D4 of about 12mm. In another embodiment, the total length L5 is about 20mm, the working length L4 is about 8mm, the horizontal length L7 of the tapered distal end is about 5mm, and the total outer diameter D4 of the balloon. It is about 8mm. In another embodiment, the total length L5 is about 15mm, the working length L4 is about 8mm, the horizontal length L7 of the tapered distal end is about 5mm, and the total outer diameter D4 of the balloon It is about 8mm. One skilled in the art would appreciate that the thin end of this balloon style may have other settings. For example, the balloon may have a series of uniform tapered lengths, rather than a single uniform tapered end. In addition, the balloon may have a curved tapered end rather than one or more uniform tapered lengths.

Similarly, the balloon may have a combination of uniform and curved lengths comprising the tapered end of the balloon. The tapered end can also be asymmetrical around the central axis of the balloon. A balloon comprising an interlaced matrix and membrane components may be of particular use in developing balloons having a tapered end or asymmetric geometry, because the interlaced material may be used to enhance shape control or create a spatial frame for the disposed balloon.

Fig. 6 illustrates a style of balloon distal protrusion 110 having a constant outer diameter D5 in a region abutting a blunt distal end 115, and a uniformly tapered proximal end 120. In one embodiment, the length Total L8 is about 20mm, L9 working length is about 8mm, and D5 outer diameter is about 12mm. In another embodiment, the total length L8 is about 20mm, the working length L9 is about 8mm, and the outside diameter D5 is about 8mm. In yet another embodiment, the total length L8 is about 15mm, the working length L9 is about 8mm, and the outside diameter D5 is about 8mm. As described earlier, one skilled in the art would appreciate that the tapered end of this balloon style may have other configurations. In addition, the surprising advantages of the balloon styles illustrated in Figs. 4-6 may be achieved using a curved or arcuate catheter.

Fig. 7 illustrates an example embodiment of the balloon of Fig. 4 having an arc of angle 0 along its working length. One skilled in the art would appreciate that more than one bow can be used on the catheter to provide surprising additional advantages to the device. Similarly, the catheter may be constructed from a shape memory metal so that the balloon may be positioned or disposed in one configuration and then repositioned or disposed in a second configuration in the surgeon's selective control. . In this way a balloon can be configured for optimal placement, placement and removal of the target cavity. For example, balloons fitted with shape memory catheters may be arranged to restore the natural anatomy of the right and left bones, or the right and left sides of the bones with a sagittal plane of symmetry. Preferably, as shown in Fig. 7 the arc of angle 0 is obtuse. In another embodiment, a number of successive arches may be incorporated into the balloon catheter to create a balloon with parallel central axes.

Similarly, the balloon styles illustrated in Figs. 4-6 and the more general balloon configurations defined by Fig. 3 and Table 1 may be angled from the central catheter.

Fig. 8 illustrates an example embodiment of balloon 70 with a uniformly angled protrusion 92. Angle 8 is preferably acute. One skilled in the art would appreciate that balloons formed for particular bone cavities or with additional surprising advantages can be developed using an angled or curved catheter made of shape memory metal as described above.

With reference to Figs. 9-16, preferred balloon configurations may also be developed from deflected balloons, including constructions with curved or angled catheters. Figs 9-12 illustrate general embodiments of an example deflected balloon.

Figs. 9 and 10 show a style of embodiment of a balloon 128, which is characterized by a deflected balloon 130 having a uniform circular protrusion 135 in the center of the balloon 130 and uniformly tapering the ends 140. The total length IOL of the balloon 130 is divided into a proximal tapered end, a central working section having uniform outer diameter D6, and a distal tapered end. The horizontal length of each of these sections can be defined relative to the distal end of the balloon. For example, the length Lll represents the horizontal distance from the distal tapered end plus the length of the center work section. Length L12 represents the horizontal length of the distal tapered end. Table 2 presents preferred general and preferred size variations for this balloon configuration by target bone anatomy. The values given in variation 1 represent generally preferred dimensions and characteristics. The values presented in variation 2, by comparison, represent more preferred criteria.

TABLE 2

PREFERRED EMBODIMENTS FOR CIRCULAR CROSS DEVIATED BALLOONS

<table> table see original document page 30 </column> </row> <table>

As described in Table 2, examples of following embodiments are directed primarily to vertebral bodies. In one embodiment, the total length IOL is about 20mm, the working length Lll is about 15mm, the horizontal distance L12 of the tapered distal end is about 3mm, and the outer diameter D6 of the circular protrusion is. about 6mm. In another embodiment, the balloon has similar dimensions except that the outside diameter D6 is about 8mm. In yet another embodiment, the balloon diameter D6 is about 12mm.

Figs. 11 and 12, in contrast, show a balloon embodiment 140 style, which is characterized by a deflected balloon 145 having a non-uniform circular protrusion 150 in the center of balloon 140 and uniformly tapered ends 155. The total length L3 of the Balloon 140 is divided into a tapered distal end, central functional section, and proximal tapered end. The balloon has no uniform cross section which can be defined by the vertical length LI6 and the width of cross section LI7. Length L14 represents the horizontal distance from the distal end of the balloon. Table 3 presents general and preferred size ranges for this balloon configuration by target bone anatomy. Values shown in range 1 represent generally preferred dimensions and characteristics. Values presented in the range of 2, by comparison, represent more preferred criteria.

TABLE 3

PREFERRED EMBODIMENTS FOR BALLOONS 20 OFFSET WITH NON-CIRCULAR CROSS SECTION

<table> table see original document page 31 </column> </row> <table>

As described in Table 3, the following exemplary embodiment is primarily directed to vertebral bodies. In one embodiment, the total length L13 is about 20mm, the functional length L14 is about 15mm, and the horizontal distance L15 from the tapered distal end is about 3mm. In addition, the vertical height L16 and lateral width L7 of balloon 145 are 14mm and 14mm, respectively.

With reference to Figs. 9 and 12, these general balloon embodiments and the present dimensions shown in Tables 2 and 3 may be combined to create complex balloons, which are inflatable structures comprised of a plurality of balloons. For example, Fig. 13 illustrates one embodiment of a complex balloon 160, and a catheter 165 adapted to employ two inflatable structures 130 and 145. In this exemplary embodiment, balloons 130 and 145 comprising complex inflatable structure 165 they are fully seated within catheter 160, and are employed through openings 170 around the circumference of catheter 165.

Fig. 14 illustrates one embodiment of a single balloon162 with two chambers 163 and 164, each of which is similar in shape to the deflected balloon style 145. In contrast, Fig. 15 illustrates another embodiment of the balloon of Fig. 14 where balloon chambers 166 and 167 are inclined with respect to longitudinal axis 158 of balloon catheter 165. In addition, in other general embodiments of complex balloons, as illustrated in Fig. 14, circular cross-section balloons , or other suitable geometric shapes, may be used.

In yet another exemplary complex balloon embodiment, Fig. 16 shows balloon 169 comprising two individual balloons 171 and 172, each having a tapered protrusion 173 and 174 which produce a complex, slanted embodiment of the balloon of Fig. 14. As the above explanation suggests, complex balloons may be constructed for bone geometries or particular clinical purposes. One skilled in the art would appreciate that tilted balloons, as illustrated in Figs. 15 and 16, may be made for anatomically correct fit as previously described without requiring an inclined catheter shaft. One skilled in the art would further appreciate the potential cost savings that a slant balloon construction may represent over a similarly shaped slant catheter balloon.

Figs. 17-25 illustrate exemplary embodiments of a catheter construction of the present invention. The basic components of the catheter are shown in Figs. 17-19. Additionally, illustrative embodiments of structural reinforcement elements are shown in Figs. 20-25. In general, the catheter may be constructed with a plurality of openings through which a balloon or plurality of balloons may be employed. For example, the catheter may have two openings through which a single balloon is employed. When the balloon is inflated, the opening-defining catheter reinforcing members cause the balloon to expand out of the catheter. Alternatively, a plurality of balloons may be employed through the windows at approximately the same time or in staggered succession. Balloons may also have different shapes, surface characteristics, or pressures to suit a particular clinical application. The following explanation illustrates non-limiting examples of the present invention using a windowed catheter through which a balloon or balloons are employed.

Fig. 17 illustrates the distal end 175 of catheter 165 of Fig. 13 in a profile view. Catheter 165 has an outer diameter D7, a proximal tip length L20, and two circumferentially opposed ballooning apertures 170 preferably the same length. The openings 170, however, may be of different length and size to accommodate a particular balloon. Remaining catheter material 180 between balloon use apertures 170 forms strips of width L21. Generally, the number of strips 180 corresponds to the number of balloon openings 170 provided in catheter 165. Similarly, the width L21 of each strip 180 may depend on the number of strips 180 provided and the outer diameter D7 of catheter 165.

Fig. 18 shows the principle of structural components of the catheter of Figs. 17 and 18. Catheter 165 is constructed of internal dimension D8, and a rod U 185 which is inserted into catheter 165 via an opening 190 at distal tip 175. The width L22 of the outer dimension of rod U 185 may be sized according to D8 so that the rod U 185 fits within and rests against the inner wall 190 of catheter 165. The length L24, the outer diameter of the individual rod 195, is related to the structural reinforcement required for the strips. intermediate catheters 180 located between the balloon use windows 170. Although the interior width L23 of the rod U 185 is related to the geometry of the interior of the catheter, the width L23 is also operatively configured to cooperate with the employed balloon or balloons.

In addition, the length L25 and length L26 of the rod U 185 preferably extend beyond the distal edge 200 of the balloon opening 170 to provide a suitable anchorage length L27 for the rod U 185 within the catheter 165. U25 and L26 U-rod segment lengths need not be equal. Rounded end 205 of stem U 185 may be fully recessed or may partially extend from proximal end 175 of catheter 165. In one embodiment, end 205 of stem U 185 is secured to catheter 165 by a solder-welded connection. white or hard solder. A glued fastener or other means of attachment may be used as well. For example, a snap joint fixation method may be used. Depending on the number of balloon openings 170 and catheter construction material 165, the number of reinforcing rods 185 will vary. Further, the means for joining a plurality of reinforcement rods 185 together and connecting the reinforcement rods 185 to catheter 165 may vary from the shown embodiments.

Fig. 19 is a sectional view through line 19-19 of Fig. 18 and shows individual reinforcing rods 195 with an exemplary cross section. In this illustrative embodiment, the reinforcing rod 206 has circular cross section. As one skilled in the art would appreciate, the reinforcement rod geometry can be selected to provide a beneficial combination of spacing and strength. For example, Figs. 20-25 illustrate individual reinforcing rods 195 with other illustrative geometric cross sections. The reinforcing rod of Fig. 20 shows a kidney-shaped cross-sectional embodiment.

Fig. 21 shows a cross-sectional reinforcing rod.

Figs. 22 and 23 show embodiments of reinforcing rod with rectangular or triangular cross sections respectively.

On the contrary, Fig. 24 shows an illustrative reinforcing rod with a circular cross section.

In addition, multiple rods may be used in place of a U-rod to accommodate a reinforced catheter with a plurality of ballooning openings. One skilled in the art will readily appreciate that a particular geometry of reinforcement rods may prove easier to manufacture, assemble or configure. Accordingly, one embodiment may prove to be a more cost-effective solution for a particular balloon configuration. For this reason, these embodiments are not intended to be a complete set of cross sections contemplated by the invention, only general illustrations of the reinforcement rod concept. Table 4 presents general dimensions for the catheter illustrated in Figs. 17-16. Values shown in range 1 represent generally preferred dimensions and characteristics. Values presented in range 2, by comparison, represent more preferred criteria.

TABLE 4

PREFERRED EMBODIMENTS FOR WINDOW CATHETERS

<table> table see original document page 36 </column> </row> <table> (a) Outside Diameter

(b) Inner Diameter

Reinforcing elements, alternatively, may be individual rails connected and oriented around the catheter perimeter by a plurality of spacer rings which are mounted on an inner lumen. The reinforcing elements may further be wire elements that are post-tensioned at the distal tip of the catheter. For this reason, the relative sizing of the balloon use window, catheter strips and reinforcement elements can be reconfigured to accommodate a particular anatomical, mechanical, therapeutic or clinical need.

For example, Fig. 25 shows a rod reinforcement structure shown in Figs. 17-24. The reinforcing member of Fig. 25 may be of tubular construction and provided with a notch 213 for use of one or more inflatable devices. The tubular reinforcement element may be formed by a special extrusion which provides, for example, thicker (i.e. sturdier) walls at selected locations. As one skilled in the art will appreciate, a tubular catheter reinforcing member may require more than one notch to accommodate a device with a plurality of balloon employment windows. Additionally, more than one balloon may be employed through each employment window. Thus, in one embodiment, a single balloon with a plurality of chambers may be employed through an employment window. In another embodiment, two separate balloons may be employed through a single job opening. In yet another embodiment, a single balloon with a plurality of chambers may be employed through an equal number of balloon employment openings.

Figs. 26-35 show complex illustrative embodiments constructed of balloons described in the above figures and tables.

Figs. 26 and 27 show a balloon catheter with three balloons and three employment windows. The complex balloon 210 comprises three deflected circular balloons 215 originating from a central catheter 220 and surrounded by an optional outer layer 225. In one embodiment, the individual balloons 215 are comprised of single layers. In another embodiment, the individual balloons may be formed from a plurality of layers and materials. Alternatively, in another embodiment, the complex balloon may comprise a single three-chamber balloon surrounded by an optional outer layer 225. One skilled in the art will readily appreciate that the thickness of each of the three layers may be different and that complex balloons can obtain large effective outside diameters with thinner balloon walls. In this way, a complex balloon can provide surprising benefits and high levels of clinical performance, including: increased puncture and tear resistance, unprecedented positioning capabilities, enhanced use, improved retractability, and ease of removal.

Figs. 28 and 29 illustrate embodiments of axial balloon 230 and 235 having uniform diameter and at least one integral pivot 240, which divides the functional length of the balloon into a plurality of segments. Adjacent balloon segments are free to move around the common joint. Fig. 30, in contrast, represents a deflected balloon 250 with two large chambers 225 connected in series. In one embodiment, a catheter tip 260 is inserted into balloon 250 to a nearly equidistant point 265 from balloon chambers 255. Referring to Fig. 31, the second chamber 270 of balloon 250 is then folded over tip 260 and in duplicate back along the length of the catheter 275. In addition, the overturned portion 270 of the balloon 255 may be attached to the non-turned portion 280 and attached to the catheter 275 near the proximal end of the balloon. In another embodiment, the folded chamber balloon is constructed of two layers. In yet another embodiment, an inner balloon is folded around the catheter and then the entire composite structure is then packaged within an additional outer layer. In one embodiment, the outer diameter D9 of balloon 250 ranges from 2mm to 12mm.

In yet another embodiment, shown in Fig. 32, a specially constructed catheter 290 may be used to provide fluid to the balloon chambers 255 in a sequential manner. During balloon inflation, fluid is prevented from being transported directly to the second chamber 270 of balloon 250 by a closed valve or block 295 in the catheter. Inflation fluid is directed to the first chamber 280 of balloon 250 via a port 300 located on the distal side of the lock 295 in catheter 290. The fluid partially charges the first balloon chamber 280 and then re-enters the catheter. 290 via an additional orifice 305 located over the proximal side of the lock 295 in catheter 290. As fluid continues to charge the first chamber 280 of balloon 250, fluid also begins to migrate through the proximal end of the blocked catheter 290 to second balloon chamber 270, via an opening at tip 260 of catheter 290.

As further shown in Fig. 32, proximal tip 260 of catheter 290 provides a fluidic connection between first, 280, and second, 270, balloon chambers 255. When balloon 255 is deflated, the fluid transport direction is reversed. In one embodiment, the lock 295 on catheter 290 is removed to allow fluid flow through the entire length of catheter 290. In another embodiment, a pressure activated valve opens to allow free fluid flow through the catheter. when the pressure in the second chamber 270 of balloon 250 becomes greater than a predetermined pressure in the first balloon chamber 280. In yet another embodiment, catheter lock 295 may be selectively controlled by the surgeon and formed of a metal with shape memory, which would provide bypass flow in one state, and direct flow by catheter in a second state.

One skilled in the art will readily appreciate that more orifices may be used as appropriate to effect the desired fluid transfer rate, and that an overturned multi-chambered balloon may be simple to assemble and test during manufacture. Thus, creating complex balloon embodiments from an overturned multiple chamber balloon 250 can also result in cost savings.

Similarly, Figs. 33-35 illustrate further examples of balloon embodiments 310, 315 and 320. Fig. 33, for example, illustrates an axially deflected balloon 325 with a uniform diameter D10 and curved shape. In one embodiment, the curved balloon 325 having longitudinal axis 330 may intimately contact the walls of the prepared bone cavity. Alignment forces applied to the balloon with bone damage facilitate a proper restoration of bone anatomy. In another embodiment, the curve is provided by a curved catheter or a shape memory metal catheter rather than shaping the shape in the balloon. In another embodiment, the curved balloon is formed of an axially deflected balloon 335 having nonuniform diameter. For example, the balloon of Fig. 34 has a diameter that varies along the longitudinal axis of the balloon. In the illustrative embodiment shown in Fig. 34, the largest diameter D11 is located at the longitudinal midpoint 340 of balloon 335. In yet another embodiment, shown in Fig. 35, balloon 320 has three chambers 350, two pivots. 355, and a curved center section 365. In another embodiment of the balloon of Fig. 35, the balloon structure 320 allows controlled inflation and deflation of the individual chambers 365, 370 and 375.

Fig. 36 illustrates a sectional view through the longitudinal axis of the spine, and shows a multi-chambered and balloon articulated 385 within a vertebral bone 390. In this embodiment, the complex balloon has the advantage of allowing selected chambers (e.g. chamber 395) are deflated first before other sections (e.g. chambers 400 and 405). In this way, cavity 410 could then be partially loaded with bone cement without deflating or removing the outer chambers of balloon 400 and 405 and the restored anatomy of bone 390 could be fully or approximately fully maintained during the fracture reduction transition. of bone for bone fixation. In another embodiment, bone loading material could be applied to the cavity when the balloon sections were deflated. In another series of embodiments, the multiple balloon chambers of Figs. 35-37 may be formed from shared septum membranes rather than narrow passages or joints.

Fig. 37, which is taken along line 37-37 of Fig. 36, illustrates a center catheter 420 with deflected circular balloons 425 and 430. When the top 430 and base 425 balloons are deflated, bone cement 430 is loaded against the outer wall 435 of the cavity 410 in the restored vertebra 390. Thereby, a controlled volume exchange between the inflated structure 430 425 and the bone loading material 430 is performed. Thus, multiple chamber balloons offer the potential for surprising advantages such as controlled volume exchange between restorative balloon and bone loading material. Similarly, an experienced technician would also readily appear that multiple chamber balloons can also be used for sequential loading of recovered bone cavities. For example, the inflated structure in a sturdier part of the bone may be deflated while balloons supporting weaker portions of the bone remain unemployed. The region of bone in which the balloon is deflated can then be loaded with bone loading material and allowed to harden or gel. Next, neighboring or other balloons may be selectively deflated and regions similarly charged. Thus, controlled deflation of a multiple chamber balloon provides temporary support to selected areas of the restored bone anatomy while other areas are loaded with bone loading material.

Fig. 38 shows an example embodiment of a balloon or containment device 440 which may be formed of biodegradable materials 445. All or part of the containment device 440 may be resorbable. Suitable biodegradable materials may comprise non-polymers (e.g. collagen), conventional biodegradable polymer materials (e.g. 70:30 materials with or without plasticizers), or polymers specially formulated for medical applications (e.g. biodegradable polyurethanes).

Non-mimicking examples of specially formulated biodegradable polyurethanes are disclosed in the following published example materials, the contents of which are fully incorporated herein by reference: (1) Gorna, K., and Gogolewski, S. "In vitro degradation of novel medical biodegradable aliphatic polyurethanes" based on e-caprolactone and Pluronics® with various hydrophilicities, "Polymer Degradation and Stability 65 (2002), pp. 9-13. 113-122; and (2) Gorna, K., and Gogolewski, S., "Novel Biodegradable Polyurethanes for Medical Applications", Synthetic Bioabsorbable Polymers for Implants, ASTM STP 1396, CM Agrawal, JE Parr, and ST Lin, Eds./American Society for Testing and Materials, WestConshohocken, PA, 2000.

However, the balloon or containment device need not comprise a resorbable material. For example, the containment device may comprise an inherently rigid polyester material that is prepared as a barrier sufficiently thin to have the desired flexibility and strength for use as a balloon or containment device. Such a barrier may be formed with or without conventional plasticizers known in the related art.

The containment device may have one or more openings 442 for receiving loading material. The containment device may be used to contain and capture various bone void carriers, such as bone cement, calcium phosphate cement, bone chips, and demineralized bone, within a bone void. The containment device 400 is inserted into a void in the bone, and the containment device is then filled with a bone void carrier. The bone void loader material may expand the containment device into the available space, or the containment device may be placed against the bone void surfaces in a partially or fully expanded position and then loaded with the void loader. bone. The device contains the carrier material, preventing extravasation (extra-bone flow) of the carrier material to surrounding tissues, which then degrades in vivo. The containment device can be used, for example, for loading bone voids into the vertebral bodies of the spine as well as long bones and the craniomaxillofacial skeleton.

Resorbable portions of the containment device may be formed from polymer films made of synthetic materials, natural materials, modified natural materials and combinations thereof. For example, materials suitable for synthesizing polymer films for the dispensing device may be formed entirely or in part of e-caprolactone-based polyurethanobiodegradable (e.g., polycaprolactone-based elastomers), which may be melt-formed into a film. solution (eg dip coating). The device may also be formed from a fusion. Another suitable polyurethane is based on polycaprolactone-polyethylene oxide-polypropylene oxide-polyethylene oxide (Pluronic). Pluronic may be dissolved, for example, in tetrahydrofuran.

Resorbable materials for preparing the containment device may also include polymers such as polyhydroxy acids, polyamines, polyamino acids, amino acid copolymers and glutaminic acid, polyorthoesters, polyanhydrides, polyamides, polydioxanone, polydioxanediones, polyestereamides, polyalic acid, diol / oxide polyesters or highly purified succinics, polycaprolactone, copolyoxalates, polycarbonates or poly (glutamic-co-leucine). Preferably used polyhydroxy acids may comprise polycopralactone, poly (L-lactide), poly (D-lactide), poly (L / D-lactide), poly (L / DL-lactide), polyglycolide, lactide and glycolide copolymers of various compositions. copolymers of said lactides and / or glycolides with other polyesters, trimethylene carbonate and glycolide copolymers, poly (trimethylene glycolide carbonate), polyhydroxybutyrate, polyhydroxyvalerate, hydroxybutyrate and hydroxyvalerate copolymers of various compositions. Other materials which may be used as additives are resorbable polymer matrix-containing composite systems and resorbable and ceramic based glasses, for example tricalcium phosphate and / or hydroxyapatite, mixed with the polymer prior to processing.

Polymeric films to form a containment device may preferably be specially designed to exhibit one or more desired properties. Specifically, polymeric films may be formulated to have specific mechanical or chemical properties. For example, polymeric films may be designed to have a Young low modulus; a high tensile strength; a fast speed of resorption; and a high elongation at break.

Polymeric films may be formulated for different rates of degradation in vivo. A polymeric film can be designed to degrade substantially in a matter of months, weeks or days. In an illustrative embodiment, a polyurethane film made of a polyurethane polymer may be designed to have a thickness of about 0.3mm and may be designed to substantially degrade in vivo within one year after implantation. In another embodiment, the polyurethane film may be designed to substantially degrade in vivo within 16 weeks after implantation. Thus, the rate of resorption and the loss of mechanical properties of the in vivo containment device can be adapted to allow maintenance of its functionality during a period of postoperative convalescence. The rate of resorption may preferably be controlled taking into account such factors as polymer weight, crystallinity, polymer chain orientation, material purity, the presence of decopolymer unit in the chain. The presence of voids (porosity) will affect the speed of resorption. In general, the rate of resorption increases in the presence of a material with voids, pores, impurities, copolymer units. The rate of degradation decreases with increasing polymer molecular weight, crystallinity and chain orientation.

Preferably, a suitable polymeric material may have an in vivo degradation rate in the range of 6 weeks to 24 months. Average molecular weight viscosity of polymers to be suitable for retainer preparation may be in the range of 30,000 to 900,000 and preferably 180,000 for elastic or semi-elastic restraint devices and preferably 300,000 to 400,000 for harder implants. Clinical treatment may also affect the polymer formulation and containment device properties. For example, a balloon or containment device to be implanted within a more severely damaged bone may require a containment device designed to degrade more slowly to provide additional structural integrity to the implant or some other therapeutic benefit. A polyurethane-based containment device, therefore, may include therapeutic materials that are beneficially released during device degradation as part of a longer-term or predetermined therapy. For example, the containment device may be designed to substantially subside over a target period of several months. In a bone void loading application, where it may be a primary objective to prevent extra-bone flow of bone-carrying material, the biodegradable polymer may preferably have a low Young modulus, high tensile strength, rapid resorption and great lengthening. The rate of film degradation can then be formulated to meet such a clinical need. In addition, the polymeric film may degrade in vivo to produce biocompatible end products that do not adversely affect the bone carrier that has been placed inside the balloon or containment device. For example, degradation products of a suitable urethane polymer device may include carbon dioxide, water and diamine.

Resorbable or degradable polymeric and / or polymeric-ceramic materials to form containment devices may have a Young modulus in the range of 1 to 10OMPa and a tensile strength in the range of 1 to 10OMPa. Young's modulus should preferably be in the range of 5 to 50MPa, more preferably in the range of 15 to 25MPa. The tensile strength should preferably be in the range of 15 to 50MPa, more preferably in the range of 25 to 35MPa. For example, the containment device may be formed of polyurethane materials synthesized from mixtures of polyethylene oxide with caprolactone or mixtures of polycaprolactone as ethylene oxide-propylene ethylene oxide triblock copolymers. These materials can have a range tensile strength of 35 to 47MPa, modules in the range of 22 to 3 IMPA. and elongation at break in the range of 600% to 900%. These materials can undergo rapid degradation. One embodiment of a caprolactone and pluronic formed polyurethane containment device (PEO-PPO-PEO) may lose 65% of its mass after about 16 weeks of degradation in vivo.

Table 5 summarizes representative values of the physical characteristics of several slides prepared from pluronic solutions (ie polycaprolactone-polyethylene oxide-polypropylbo oxide). Each blade had an area of about 150mm x 150mm and was about 0.3mm thick.

TABLE 5

ILLUSTRATIVE PHYSICAL PROPERTIES FOR RESERVABLE IMMERIABLE POLY DELAMINE EXAMPLES

<table> table see original document page 46 </column> </row> <table> Notes:

(a) Pluronic (polycaprolactone-polyethylene oxide-polypropylene oxide-polyethylene oxide);

(b) Polycaprolactone, and polyethylene oxide;

(c) e-caprolactone.

Table 6, by contrast, summarizes the preferred physical properties for a pluronic based containment device for low pressure applications. In this application, the containment device may be designed to prevent leakage when a void in the bone is loaded with a carrier material such as debris cement.

TABLE 6

PHYSICAL PROPERTIES SELECTED FOR AN EXEMPLODE RESERVABLE CONTAINMENT DEVICE (A)

<table> table see original document page 47 </column> </row> <table>

(a) Pluronic based film, area (150mm x 150mm), thickness (0.3mm).

Resorbable containment devices may be made by solution molding successive layers of polymeric film onto a mandrel or mold. For example, a Pluronic based polyurethane polymer having a viscosity - average molecular weight of 104,000 Dalton may be used to prepare the polymeric film. In another example, a Pluronic-based polyurethane may be dissolved in tetrahydrofuran to prepare a 2.5 weight / voltage-% solution. Other Pluronic-based polymeric materials having a different average molecular weight viscosity and / or polymer concentration may also be used to prepare polymeric application for the containment device. Pluronic based materials having an average molecular weight viscosity of 180,000 Dalton, a polymer concentration of 3%, 4%, or 5% can be prepared as well. The concentration of the copolymer unit in the polymer may be in the range of about 1 to about 99% and preferably in the range of about 2.5 to about 35%. The polymeric material may have at least one partially oriented structure.

Referring to Fig. 38, the resorbable containment device 440 may be formed by solution molding a polymeric film onto a mandrel or mold 450 (shown in Fig. 39). In general, polymer concentration affects the number of layers that may need to be deposited on a mandrel or mold to achieve the desired biodegradable film thickness. For example, solution casting of 25 to 30 layers of polymer may be required to form a film having a thickness of approximately 0.3mm over a mandrel through a solution of pluronic material having, for example, an average pesomolecular viscosity of 104,000 Dalton. . The resulting polymeric film may have a tensile strength of about 26MPa and an 18MPa fence tensile modulus. Similarly, 25- to 30-layer polymer solution molding can form a film having a thickness of approximately 0.3mm over a mandrel of a solution of depluronic material having, for example, an average molecular weight viscosity of 180,000 Dalton. This polymeric film can have a tensile strength of about 35MPa and a tensile modulus of about 22MPa. Less than 25-30 layers of polymeric film may need to be deposited on the mandrel to obtain a similar film thickness when the concentration of polymer solution is greater.

Referring to Fig. 39, a preferred method for making a containment device from a pluronic-based solution is to provide a mandrel 450 with a first portion 455 having a containment device (or balloon) shape to be formed and a second coupled portion 460. to the first portion having a handle to allow insertion of mold 450 into the polymer solution and rotating the mold 450 to evenly distribute the polymer solution over the mold surface 465. Preferably, the mandrel 450 may be formed of stainless steel and may be polished to facilitate the removal of the molded balloon. Alternatively, the mandrel 450 may be made of PTFE (ie Teflon ™). Wrinkles that may form during polymer solidification on the film surface may result in lower tensile strength and lower tensile modulus.

Referring again to Fig. 38, the device wall 470 may preferably have a regular surface and substantially uniform thickness. Resorbable containment device 440 may also have any texture, shape, or size as described above. Of this, the inflatable devices shown in Figs. 4-16 (or molds having a similar shape) may be used for solution molding of a resorbable containment device. For example, the balloon of Fig. 6 may be used as the mold for solution molding of a resorbable holding device. The mold may be treated with one or more materials, such as by spraying or dipping to provide a lubricating barrier to facilitate separation of the newly formed resorbable containment device from the balloon mold. For example, materials that melt at a temperature lower than the polymer device may be used as the sacrificial layer to separate the polymer containment device from the mold.

Referring to Fig. 40, an absorbable containment device 485 formed of composite materials may also be formed by solution molding. For example, the resilient containment device 475 may incorporate a filament 480, which may be formed of biodegradable materials, bio-inert materials, or a combination thereof. Filament 480, for example, may be formed of a medical grade metal, polymer material, suture material or other suitable composition. The filament 480 need not provide uniform coverage over the containment device 475 and may be selectively placed in certain areas of the containment device. One or more filaments may also form a tissue member. The filament 480 may cover a containment device in a uniform or non-uniform manner. For example, filament 480 with an increasingly dense pattern 485 of placement on tapered sections 490 of retention device 475 may be used.

Fig. 41 shows an exemplary containment device 475 having a filament 480 with a placement pattern 495 having a higher filament density 480 than the device shown in Fig. 40. Figs. 42 and 43 show exemplary embodiments of preformed stockings 500, 505 of filament 480 which may be placed over a mold like mold 450 shown in Fig. 39. Filament 480 may otherwise be bandaged over mold 450 to from a reel of material. The reel may contain a single strand, or filament, or may comprise more than one strand which has been weaved together to form a composite rope. Similarly, the reel may contain coated or coaxial wires and strings.

A resorbable containment device 440 may then be molded by solution onto the mold 450 and filament 480. The filament 480 may also be placed over a partially or completely molded containment device. Molding of additional resorbable polymer solution can then be applied to partially or completely cover the tapering. Thus, a resilient holding device 440 may be formed with a filament 480 located within the resilient holding device wall 445, on the inner surface of the holding device, or on the outer surface 470 of the holding device.

Resorbable containment devices may also be made from individually molded molds. Individually formed sections of resorbable polymer may be applied directly to the bone or may be combined to create larger barriers or containment structures. For example, individual parts of a decomposition containment device may be joined and / or sealed together for low pressure loading with bone cement in vivo by drip coating joints between individual parts of the pluronic based solution and composite delivery device. Alternatively, any suitable adhesive may be used to join pieces together in a unitary structure. Individual sections of resorbable polymer may also be sewn together with suture material. The seam may be designed to provide a leak free structure or may require additional sealing of the seams. Automatic spray coating of CAD / CAM formed molds and other known processes may be used to form containment devices for a wide variety of shapes, sizes and materials. . Resorbable containment devices can also be produced using standard polymer processing techniques, primarily by injection molding, compression molding and polymerization in the mold.

While the above invention has been described with reference to preferred embodiments, it should be remembered that the scope of the present invention is not limited to these embodiments. For example, the containment device may be formed with a filament extending from the resorbable polymer to form a free end. The free end may be used to secure the containment device or tie the opening. The above embodiments may also be modified so that some features of one embodiment are used with features of another embodiment. One skilled in the art may find variations of these preferred embodiments which, however, will be within the spirit of the present invention, the scope of which is defined by the claims set forth below.

Claims (31)

1. Device for containing material within bone, comprising: a barrier member configured and adapted for insertion into bone, the barrier member having internal and external surfaces, the internal surface defining a space, where the barrier member is capable of preventing fluid within the space from passing through the inner surface to the outer surface, and the barrier member comprising a polyurethane polymer based on at least one of the group consisting of caprolactone and Pluronic, so that the barrier member is capable of degrade into biologically compatible living substances. Device according to claim 1, characterized in that the flexible material comprises a plasticizer. Device according to claim 2, characterized in that the flexible material is a resorbable material. Device according to claim 3, characterized in that the flexible material has high elongation. Device according to claim 1, characterized in that the flexible material has an elongation at break of between about 1,000% and 2,000%. Device according to claim 1, characterized in that the flexible material has a Young modulus between about 10OMPa and about 10OMPa. Device according to claim 1, characterized in that the flexible material has a tensile strength at break of about 5 and about 10OMPa. Device according to claim 1, characterized in that the barrier member comprises a plurality of layers. Device according to claim 8, characterized in that the barrier member has a tensile strength between about 15 and about 50MPa. Device according to claim 8, characterized in that the barrier member has a tensile strength between about 25MPa and about 35MPa. Device according to claim 8, characterized in that the barrier member has a Young modulus between about 5MPa and about 30MPa. Device according to claim 11, characterized in that the barrier member has a Young modulus of about 15MPa and about 25MPa. Device according to claim 11, characterized in that the barrier member has an elongation at break of between about 600% and 1000%. Device according to claim 13, characterized in that the barrier member has an elongation at break of between about 850% and 950%. Device according to claim 13, characterized in that the barrier member has an average molecular weight between about 100,000 and about 200,000 Dalton. Device according to claim 15, characterized in that the barrier member has an average molecular weight between about 150,000 and about 190,000 Dalton. Device according to claim 1, characterized in that the barrier member has mass and the mass degrades in vivo after the device is implanted into bone. Device according to claim 17, characterized in that more than 60% of the mass degrades after about 2 weeks of in vivo degradation. Device according to claim 18, characterized in that the barrier member has a thickness of about 0.5 mm. Device according to Claim 19, characterized in that the mass degrades in vivo to produce carbon dioxide, water and diamine. A method of forming a resilient containment device, comprising: providing a mold, providing a polymer, depositing a plurality of layers of the polymer onto the mold to form the resorbable containment device; remove the resorbable containment device from the mold. The method of claim 21, further comprising treating the mold with at least one lubricating material to provide a lubricating barrier to facilitate removal of the resorbable mold holding device. A method according to claim 22, characterized in that it further comprises spraying the mold with at least one lubricating material. A method according to claim 22, characterized in that it further comprises dipping the mold into less a lubricating material. A method according to claim 21, characterized in that it further comprises positioning at least one filament over the mold. The method of claim 25, characterized in that it further comprises forming a woven limb with appeal minus a filament. A method according to claim 21, characterized in that it further comprises positioning at least one filament over one of a partially formed and fully resorbable containment device. A method according to claim 21, characterized in that it further comprises: positioning at least one filament over a partially formed resorbable holding device and depositing additional polymer on the filament side wall. A method according to claim 21, characterized in that it further comprises forming the stainless steel mold and the stainless steel perch. A method according to claim 21, characterized in that it further comprises forming the PTFE mold. The method of claim 21, characterized in that the step of depositing a plurality of polymer layers onto the mold comprises melting the solution.