Inflatable bone tamp with flow control and methods of use

An inflatable bone tamp is provided that includes a shaft defining a lumen. A balloon is coupled to the shaft such that a material can flow through the lumen and into the balloon to inflate the balloon. A connector is coupled to the shaft. The connector includes a first port and a second port. The ports are in communication with the lumen. A flow control device is coupled to the first port. The flow control device controls flow of the material through the first port and into the lumen. A damper is coupled to the second port. The damper controls pressure within the inflatable bone tamp when pressure within the inflatable bone tamp reaches a threshold. Kits, systems and methods are disclosed.

TECHNICAL FIELD

The present disclosure generally relates to medical devices for the treatment of bone disorders, and more particularly to devices and methods for treating spinal disorders, such as, for example, vertebral compression fractures.

BACKGROUND

Height loss is commonly associated with spinal fractures, such as, for example, vertebral compression fractures. Spinal fractures affect a large segment of osteoporotic patients. It is estimated that approximately 700,000 spinal fractures occur annually from osteoporosis, for example. Procedures have been developed to treat spinal fractures. One such procedure is kyphoplasty. Kyphoplasty is a minimally invasive procedure that is used to treat spinal fractures, such as, for example, vertebral compression fractures by inserting one or more balloons, such as, for example, compliant balloons inside a fractured vertebral body. The balloon or balloons are inflated within the fractured vertebral body such that the cancellous bone of the vertebral body is pushed towards cortical walls of the vertebral body to form a cavity within the vertebral body. The cavity is then at least partially filled with a material, such as, for example, bone cement.

However, conventional spinal fracture treatment procedures lack a means to control the inflation rate of the balloon or balloons. This may lead to uneven inflation, balloon ruptures, or suboptimal balloon performance. To achieve optimal results, there is a need to provide a balloon or balloons that are inflated slowly to allow the balloon or balloons to gradually compress bone and restore height to the vertebral body. Bone is a viscoplastic material that needs time to deform. Fast inflation does not allow the balloon to create a large cavity. Conventional spinal fracture treatment procedures rely on the physician to control the inflation rate of the balloon or balloons. Inflating at a lower rate is not typically desired because it leads to a longer procedure time. However, providing a more steady and uniform inflation rate as described herein will lead to better and more predictable patient outcomes.

SUMMARY

New devices and methods are provided for the treatment of bone disorders, and more particularly devices and methods for treating spinal disorders, such as, for example, vertebral compression fractures. In some embodiments, the devices comprise an inflatable bone tamp (IBT) that includes a shaft defining a lumen. A balloon is coupled to the shaft such that a material can flow through the lumen and into the balloon to inflate the balloon. A connector is coupled to the shaft. The connector includes a first port and a second port. The ports are in communication with the lumen. A flow control device is coupled to the first port. The flow control device controls flow of the material through the first port and into the lumen. A damper is coupled to the second port. The damper controls pressure within the inflatable bone tamp when pressure within the inflatable bone tamp reaches a threshold.

DETAILED DESCRIPTION

Various components of balloon catheter40may have material composites, including the above materials, to achieve various desired characteristics such as strength, rigidity, elasticity, compliance, biomechanical performance, durability and radiolucency or imaging preference. The components of balloon catheter40, individually or collectively, may also be fabricated from a heterogeneous material such as a combination of two or more of the above-described materials. The components of balloon catheter40may be monolithically formed, integrally connected or comprise fastening elements and/or instruments, as described herein.

Balloon catheter40comprises an outer shaft or cannula, such as, for example, cylindrical portion42and a balloon44coupled to cylindrical portion42. In the embodiments shown inFIGS. 1 and 2, a proximal portion44aof balloon44is coupled to cylindrical portion42and an opposite distal portion44bof balloon44is spaced apart from or nonadjacent to the cylindrical portion42. Cylindrical portion42is hollow and defines a passageway46. In some embodiments, passageway46is in communication with an internal chamber48of balloon44. In some embodiments, passageway46is configured to for passage of a material to move balloon44from an unexpanded configuration, such as, for example, an uninflated configuration to an expanded configuration, such as, for example, an inflated configuration. That is, a material may be moved through lumen or passageway46and into chamber48to move balloon44from the uninflated configuration to the inflated configuration. In some embodiments, when balloon44is in the inflated configuration, balloon44has a maximum diameter that is greater than the maximum diameter of balloon44when balloon44is in the uninflated configuration. That is, balloon44expands radially as balloon44moves from the uninflated configuration to the inflated configuration. In some embodiments, when balloon44is in the inflated configuration, balloon44has a maximum length that is greater than the maximum length of balloon44when balloon44is in the uninflated configuration. That is, balloon44expands longitudinally as balloon44moves from the uninflated configuration to the inflated configuration. In some embodiments, the material is a liquid, such as, for example, a contrast solution, saline or water. In some embodiments, passageway46is configured for passage of a material to move balloon44from the inflated configuration to the uninflated configuration, as discussed herein. That is, the material moves through passageway46and out of balloon catheter40to allow balloon44to deflate.

In some embodiments, cylindrical portion42is a hollow shaft or tube. In some embodiments, cylindrical portion42is flexible to allow cylindrical portion42to bend as cylindrical portion42is navigated through a patient's anatomy. For example, cylindrical portion42may be flexible to allow cylindrical portion42to be navigated along a curved path created by a medical practitioner in order to position balloon44at, in or near a target location or treatment zone, such as, for example, within a vertebral body. In embodiments wherein cylindrical portion42is flexible, cylindrical portion42can be bent without breaking cylindrical portion42. In some embodiments, cylindrical portion42is rigid such that cylindrical portion42cannot be bent without cylindrical portion42breaking. For example, cylindrical portion42may be rigid to provide strength to cylindrical portion42in applications wherein balloon catheter40is navigated along a straight path created by a medical practitioner in order to position balloon44at, in or near a target location or treatment zone, such as, for example, a space within a vertebral body. In some embodiments, cylindrical portion42is a polymer tube.

In some embodiments, balloon44is made from a resilient biocompatible material. In one embodiment, balloon44is a compliant balloon that resists stretching. In one embodiment, balloon44comprises polyolefin copolymer (POC), Polyurethane, Nylon. In one embodiment, balloon44is a non-compliant or semi-compliant balloon that stretches, at least to some degree. In one embodiment, balloon44comprises polyethylene terapthelate (PET). In some embodiments, balloon44can have various cross section configurations when balloon44is in the inflated configuration, such as, for example, oval, oblong, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. In some embodiments, an outer surface of balloon44may have various surface configurations, such as, for example, smooth and/or surface configurations to enhance fixation with tissue, such as, for example, rough, arcuate, undulating, porous, semi-porous, dimpled, polished and/or textured.

Balloon44can be a single or a multi-layered balloon, where each balloon layer has the same diameter and/or wall thickness, is comprised of the same material or materials having substantially identical mechanical properties, and has the same degree of molecular orientation in the body portion of the balloon. It will be apparent that in some situations it will be desirable to have some balloon layers having different thicknesses, materials, and/or degree of molecular orientations upon deflation, while at the same time having equivalent size, mechanical properties, and/or orientation upon inflation.

Balloon catheter40comprises a connector50that is coupled to cylindrical portion42. Connector50comprises a port52and a port54that is spaced apart from port52. One or more flow control devices, such as, for example, a flow control device56is coupled to port52such that a channel58of flow control device56is in communication with passageway46. This allows an inflation device, such as, for example, a syringe S to be coupled to port52such that syringe S can inject a material through channel58and passageway46and into inner cavity48to move balloon44from the uninflated configuration to the inflated configuration. Flow control device is configured to restrict or otherwise limit the rate of flow of a material as the material flows through channel58, as discussed herein. In some embodiments, channel58extends parallel and is coaxial with passageway46, as shown inFIGS. 1 and 2. In some embodiments, channel58may be disposed at alternate orientations, relative to passageway46, such as, for example, transverse, perpendicular and/or other angular orientations such as acute or obtuse and/or may be offset or staggered. In some embodiments, channel58may have various cross section configurations, such as, for example, oval, oblong, triangular, rectangular, square, polygonal, irregular, uniform, non-uniform, variable, tubular and/or tapered. In some embodiments, coupled to port52by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element.

In some embodiments, flow control device56is integrally formed with connector50such that flow control device56cannot be removed from connector50without breaking connector50and/or flow control device56. In some embodiments, flow control device56is removable from connector50to allow a medical practitioner to select between differently configured flow control devices that can be coupled to port52. For example, the medical practitioner can select a flow control device, such as, for example, flow control device56from a plurality of flow control devices that each restrict or otherwise limit the rate of flow of a material as the material flows through channel58differently. For example, when a faster rate of flow is desired, the medical practitioner can select the flow control device that allows for a faster rate of flow. If, on the other hand, a slower rate of flow is desired, the medical practitioner can select the flow control device that allows for a slower rate of flow. The differently configured flow control devices may be part of a kit, which is within the scope of the present disclosure. In embodiments wherein flow control device56is removable from connector50, flow control device56may be coupled to connector50by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element.

In some embodiments, channel58is tapered to restrict or otherwise limit the rate of flow of a material as the material flows through channel58and into passageway46. It is envisioned that this will slow the flow rate of the material as the material moves into interior cavity48of balloon44from passageway46to move balloon44from the uninflated configuration to the inflated configuration. That is, the flow rate of the material will be less when channel58is tapered than when channel is not tapered, such as, for example, when channel58has a uniform width or diameter.

Channel58can be tapered in different ways to restrict or otherwise limit the rate of flow of the material through channel58. In some embodiments, flow control device56comprises a convexly curved inner surface such that channel58is tapered from a proximal end of flow control device56to a midpoint of flow control device56and from a distal end of flow control device56to the midpoint, as shown inFIGS. 1 and 2. In some embodiments, the inner surface is continuously curved from the proximal end of flow control device56to the midpoint of flow control device56and continuously curved from the distal end of flow control device56to the midpoint. In some embodiments, the inner surface has a continuous radius of curvature from the proximal end of flow control device56to the midpoint of flow control device56and a continuous radius of curvature from the distal end of flow control device56to the midpoint. In some embodiments, channel58is tapered from the distal end of flow control device56to the proximal end of flow control device56, as shown inFIG. 1A. In some embodiments, channel58is tapered continuously from the proximal end of flow control device56to the distal end of flow control device56. In some embodiments, channel58is tapered from a proximal end of flow control device56to the distal end of flow control device56, as shown inFIG. 1B. In some embodiments, channel58is tapered continuously from the distal end of flow control device56to the proximal end of flow control device56. In some embodiments, channel58includes a stepped configuration, as shown inFIG. 1C, such that the diameter of channel58decreases incrementally along the length of channel58.

In one embodiment, shown inFIG. 1D, flow control device56comprises a member60positioned within channel58. Member60comprises one or a plurality of pores62that are in communication with channel58such that a material can move from an inflation device, such as, for example, syringe S, through pores62and into passageway46. In some embodiments, member60is an open cell foam material or spongiform material/structure. In some embodiments, at least one of pores62extends through opposite proximal and distal surfaces60a,60bof a respective member60. In some embodiments, at least one of pores62extends through one of proximal and distal surfaces60a,60bwithout extending through the other one of proximal and distal surfaces60a,60b. In some embodiments, at least one of pores62is in communication with at least another one of pores62. In some embodiments, pores62are interconnected with one another. In some embodiments, pores62are spaced apart from nonadjacent to one another and/or are not in communication with one another.

One or more valves, such as, for example, a check valve or damper64is coupled to port54. A cavity66of port54is in communication with passageway46. Damper64is in communication with passageway or cavity66of port54such that damper64is affected by pressure within passageway46. In some embodiments, damper64includes a biasing member, such as, for example, a coiled spring68that contracts or compresses in response to increased pressure within passageway46and expands in response to decreased pressure within passageway46. The compression and expansion of spring68allows damper64to smoothen pressure peaks within passageway46. As such, damper46can prevent pressure within passageway46from increasing too quickly, for example. That is, damper46takes the blunt force of the fast rising pressure within passageway46. In some embodiments, damper46is configured such that spring68will compress only when pressure within passageway46reaches a certain threshold.

In some embodiments, balloon catheter40comprises a plurality of dampers, such as, for example, damper64that can each be removably coupled to port54. In some embodiments, each of dampers64is configured such that springs68compress at a different threshold pressure. This allows a medical practitioner to select a damper64that works at a selected threshold pressure. In embodiments wherein dampers64are removable from connector50, damper64may be coupled to port54by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element.

In operation and use, an inflation device, such as, for example, syringe S is coupled to port52. In some embodiments, a distal tip of syringe S is coupled to flow control device56, as shown inFIG. 2. In some embodiments, the distal tip of syringe S includes outer threads that engage inner threads of flow control device56to couple syringe S to flow control device56. A plunger70of syringe S is moved in direction A shown inFIG. 2such that a tip72of plunger70pushes material, such as, for example, inflation material within a cavity74of a barrel76of syringe S out of cavity74. The material moves out of syringe S and through channel58of flow control device56. As the material moves through channel58, the rate of flow of the material is reduced, as discussed herein. That is, the rate of flow of the material decreases within channel58from the rate of flow when the material exits syringe S. The material then flows through passageway46at the reduced rate of flow and into inner cavity48of balloon44to move balloon from the uninflated configuration to the inflated configuration. As the material flows through passageway46, spring68of damper66will compress if pressure within passageway46reaches a certain threshold in order to smoothen pressure peaks within passageway46, as discussed herein. In some embodiments, the material may be withdrawn from balloon44by moving plunger70in the direction shown by arrow B inFIG. 2. In particular, moving plunger70in the direction shown by arrow B creates pressure that draws the material out of inner cavity48, through passageway46and channel58and into syringe S to move balloon44from the inflated configuration to the uninflated configuration.

In use, to treat a bone disorder, such as, for example, a spinal fracture, a medical practitioner obtains access to a target location including at least one vertebra, such as, for example, a fractured vertebra, in any appropriate manner, such as through incision and retraction of tissue. It is envisioned that the balloon catheter40may be used in any existing surgical method or technique including open surgery, mini-open surgery, minimally invasive surgery including percutaneous surgical implantation, whereby vertebra V is accessed through a micro-incision, or sleeve that provides a protected passageway to the area. Once access to the surgical site(s) are obtained, the particular surgical procedure is performed for treating the bone disorder.

Balloon catheter40is moved through the incision and positioned so that balloon44is positioned within a vertebral body of the fractured vertebra. In some embodiments, balloon44is moved into the vertebral body when balloon44is in the uninflated configuration. The material discussed above is moved through passageway46such that the material flows through passageway46, channel58and into cavity48of balloon44to move balloon44from the uninflated configuration to the inflated configuration. As balloon44is gradually inflated, balloon44pushes cancellous bone of the vertebral body towards cortical walls of the vertebral body to form a cavity within the vertebral body. In some embodiments, the cavity created by balloon44is filled with a material, such as, for example, bone cement.

In some embodiments, balloon catheter40comprises a shaft, such as, for example, an inner shaft84positioned within cylindrical portion42, as shown inFIGS. 3-5, for example. A distal portion of shaft84extends through an opening78of cylindrical portion42such that at least a portion of the distal portion of shaft84is positioned outside of passageway46of cylindrical portion42. Proximal portion44aof balloon44is coupled to a distal portion of cylindrical portion42and distal portion44bof balloon44is coupled to shaft84. In some embodiments, shaft84comprises an inner surface defining a passageway, such as, for example, a lumen86and one or a plurality of apertures88that are in communication with lumen86and cavity48of balloon44such that an inflation material can be moved through lumen86and apertures88and into cavity48to inflate balloon44. In some embodiments, apertures88are spaced apart from one another radially about a circumference of inner shaft84. In some embodiments, inner shaft84comprises an end wall90that defines a distal limit of lumen86. In some embodiments, balloon catheter40comprises a plug92in a distal end of shaft84that closes lumen86to define a distal limit of lumen86. In some embodiments, end wall90is a portion of plug92.

Connector50is coupled to shaft84such that channel58of flow control device56is in communication with lumen86. In some embodiments, channel58is coaxial with lumen86. In the embodiments shown inFIGS. 3-5, cavity66of port54is in communication with openings in cylindrical portion42and shaft84such that cavity66is in communication with lumen86. In some embodiments, cavity66is closed off from passageway46by a wall that defines cavity66such that cavity66is not in communication with passageway46. Connector50includes a port94that is spaced apart from port52and from port54. Port94includes a conduit96that is defined by a wall of port94. Conduit96is in communication with an opening in cylindrical portion42such that conduit96is in communication with passageway46. In some embodiments, conduit96is closed off from lumen86by a wall of shaft84that defines lumen86such that conduit96is not in communication with lumen86. A valve, such as, for example, an EZ prep valve98is coupled to port94. Valve98is configured for removal of inflation material from balloon catheter40, as discussed herein. In some embodiments, valve98is integrally formed with port94such that valve98cannot be removed from port94without breaking valve98and/or port94. In some embodiments, valve98is removable coupled to port94. Valve98may be coupled to port94by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element. Valve98includes a passage100that is in communication with conduit96. In some embodiments, a removable cap102is coupled to valve98to close off passage100, as shown inFIG. 3. In some embodiments, inner threads of cap102engage outer threads of valve98to couple cap102to valve98. In some embodiments, cap102may be coupled to valve98by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element. In some embodiments, cap102is a Luer cap.

In operation and use, an inflation device, such as, for example, syringe S is coupled to port52. In some embodiments, the distal tip of syringe S is coupled to flow control device56, as shown inFIG. 4. In some embodiments, the distal tip of syringe S includes outer threads that engage inner threads of flow control device56to couple syringe S to flow control device56. Plunger70of syringe S is moved in direction C shown inFIG. 4such that tip72of plunger70pushes material, such as, for example, inflation material within cavity74of barrel76of syringe S out of cavity74. The material moves out of syringe S and through channel58of flow control device56. As the material moves through channel58, the rate of flow of the material is reduced, as discussed herein. That is, the rate of flow of the material decreases within channel58from the rate of flow when the material exits syringe S. The material then flows through lumen86and apertures88of shaft84at the reduced rate of flow and into inner cavity48of balloon44to move balloon from the uninflated configuration to the inflated configuration. As the material flows through lumen86, spring68of damper66will compress if pressure within lumen86reaches a certain threshold in order to smoothen pressure peaks within lumen86, as discussed herein. In some embodiments, the material fills all or a portion of passageway46as the material moves through apertures88and into inner cavity48.

In some embodiments, balloon44is moved from the inflated configuration to the uninflated configuration by removing cap102from valve98, as shown inFIG. 5. Once cap102is removed from valve98, the material in passageway46may flow out of balloon catheter40through conduit96and passage100in direction D shown inFIG. 5. In some embodiments, a suction device, such as, for example, a second syringe S may be coupled to valve98to assist in removing the material in passageway46from balloon catheter40. In some embodiments, coupled to port52by frictional engagement, threaded engagement, mutual grooves, screws, adhesive, nails, barbs and/or raised element. To remove the material in passageway46from balloon catheter40using second syringe S, plunger70of second syringe S is moved relative to barrel76in direction E shown inFIG. 4such that the material in inner cavity48of balloon44is drawn through passageway46, conduit96and passage100and into cavity74of syringe S. As the material exits inner cavity48, balloon44moves from the inflated configuration to the uninflated configuration. In some embodiments, balloon44is moved from the inflated configuration to the uninflated configuration while syringe S is coupled to flow control device56. In some embodiments, balloon44is moved from the inflated configuration to the uninflated configuration after syringe S is uncoupled from flow control device56.

In use, to treat a bone disorder, such as, for example, a spinal fracture, a medical practitioner obtains access to a target location including at least one vertebra, such as, for example, a fractured vertebra, in any appropriate manner, such as through incision and retraction of tissue. It is envisioned that the balloon catheter40may be used in any existing surgical method or technique including open surgery, mini-open surgery, minimally invasive surgery including percutaneous surgical implantation, whereby vertebra V is accessed through a micro-incision, or sleeve that provides a protected passageway to the area. Once access to the surgical site(s) are obtained, the particular surgical procedure is performed for treating the bone disorder.

Balloon catheter40is moved through the incision and positioned so that balloon44is positioned within a vertebral body of the fractured vertebra. In some embodiments, balloon44is moved into the vertebral body when balloon44is in the uninflated configuration. The material discussed above is moved through lumen86such that the material flows through channel58and lumen86and into cavity48of balloon44to move balloon44from the uninflated configuration to the inflated configuration. As balloon44is gradually inflated, balloon44pushes cancellous bone of the vertebral body towards cortical walls of the vertebral body to form a cavity within the vertebral body. In some embodiments, balloon44is moved from the inflated configuration to the uninflated configuration in the manner discussed herein. Balloon catheter may then be removed from the incision. Another device may be used to fill the cavity created by balloon44with a material, such as, for example, bone cement.

In some embodiments, a kit containing one or more components of balloon catheter40is provided. The kit may comprise components from any of the embodiments discussed herein. In some embodiments, the kit comprises one or more of the inflation materials discussed herein. The kit may also comprise one or more component to assist with inserting balloon catheter40into a patient, such as, for example, one or a plurality of cannulas. In some embodiments, the kit comprises a plurality of cannulas having different lengths configured for use with different size patients.