Apparatus and method for creating cavities in interior body regions
A shaft member is sized and configured for introduction through a percutaneous access path into a cancellous bone volume. The shaft has an elongated axis. A cutting blade is sized and configured to be carried by the shaft member and project radially outward of the elongated axis into contact with cancellous bone. The cutting blade is capable of cutting cancellous bone in a path about the elongated axis in response to rotation of the shaft member within cancellous bone.
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This application is a divisional of application Ser. No. 10/958,944, filed Oct. 5, 2004, and entitled “Structures and Methods for Creating Cavities in Interior Body Regions,” which is a divisional of application Ser. No. 10/208,391, filed Jul. 30, 2002 (now U.S. Pat. No. 6,863,672), which is a divisional of application Ser. No. 09/055,805, filed Apr. 6, 1998 (now U.S. Pat. No. 6,440,138), each of which is incorporated herein by reference.
FIELD OF THE INVENTIONThe invention relates to structures and procedures, which, in use, form cavities in interior body regions of humans and other animals for diagnostic or therapeutic purposes.
BACKGROUND OF THE INVENTIONCertain diagnostic or therapeutic procedures require the formation of a cavity in an interior body region.
For example, as disclosed in U.S. Pat. Nos. 4,969,888 and 5,108,404, an expandable body is deployed to form a cavity in cancellous bone tissue, as part of a therapeutic procedure that fixes fractures or other abnormal bone conditions, both osteoporotic and non-osteoporotic in origin. The expandable body compresses the cancellous bone to form an interior cavity. The cavity receives a filling material, which provides renewed interior structural support for cortical bone.
This procedure can be used to treat cortical bone, which due to osteoporosis, avascular necrosis, cancer, or trauma, is fractured or is prone to compression fracture or collapse. These conditions, if not successfully treated, can result in deformities, chronic complications, and an overall adverse impact upon the quality of life.
A demand exists for alternative systems or methods which, like the expandable body shown in U.S. Pat. Nos. 4,969,888 and 5,108,404, are capable of forming cavities in bone and other interior body regions in safe and efficacious ways.
SUMMARY OF THE INVENTIONThe invention provides an apparatus and associated method that comprise a shaft member sized and configured for introduction through a percutaneous access path into a cancellous bone volume. The shaft has an elongated axis. The apparatus and method also include a cutting blade sized and configured to be carried by the shaft member and project radially outward of the elongated axis into contact with cancellous bone. The cutting blade is capable of cutting cancellous bone in a path about the elongated axis in response to rotation of the shaft member within cancellous bone.
Features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSThe systems and methods embodying the invention can be adapted for use virtually in any interior body region, where the formation of a cavity within tissue is required for a therapeutic or diagnostic purpose. The preferred embodiments show the invention in association with systems and methods used to treat bones. This is because the systems and methods which embody the invention are well suited for use in this environment. It should be appreciated that the systems and methods which embody features of the invention can be used in other interior body regions, as well.
I. Rotatable Cavity Forming Structures
A. Rotatable Loop Structure
The catheter tube 12 carries a cavity forming structure 20 at its distal end 16. In the illustrated embodiment, the structure 20 comprises a filament 22 of resilient inert material, which is bent back upon itself and preformed with resilient memory to form a loop.
The material from which the filament 22 is made can be resilient, inert wire, like stainless steel. Alternatively, resilient injection molded inert plastic or shape memory material, like nickel titanium (commercially available as Nitinol™ material), can also be used. The filament 22 can, in cross section, be round, rectilinear, or an other configuration.
As
As
As
In use (see
When free of the guide sheath 34, the physician is also able to rotate the deployed loop structure 20, by rotating the catheter tube 12 within the guide sheath 34 (arrow R in
The materials for the catheter tube 12 are selected to facilitate advancement and rotation of the loop structure 20. The catheter tube 12 can be constructed, for example, using standard flexible, medical grade plastic materials, like vinyl, nylon, polyethylenes, ionomer, polyurethane, and polyethylene tetraphthalate (PET). The catheter tube 12 can also include more rigid materials to impart greater stiffness and thereby aid in its manipulation and torque transmission capabilities. More rigid materials that can be used for this purpose include stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys.
The filament 22 preferably carries one or more radiological markers 36. The markers 36 are made from known radiopaque materials, like platinum, gold, calcium, tantalum, and other heavy metals. At least one marker 36 is placed at or near the distal extremity of the loop structure 20, while other markers can be placed at spaced apart locations on the loop structure 20. The distal end 16 of the catheter tube 12 can also carry markers. The markers 36 permit radiologic visualization of the loop structure 20 and catheter tube 12 within the targeted treatment area.
Of course, other forms of markers can be used to allow the physician to visualize the location and shape of the loop structure 20 within the targeted treatment area.
B. Rotatable Brush
The distal end 42 of the drive shaft carries a cavity forming structure 44, which comprises an array of filaments forming bristles 46. As
The material from which the bristles 46 is made can be stainless steel, or injection molded inert plastic, or shape memory material, like nickel titanium. The bristles 46 can, in cross section, be round, rectilinear, or an other configuration.
The proximal end 52 of the drive shaft 40 carries a fitting 54 that, in use, is coupled to an electric motor 56 for rotating the drive shaft 40, and, with it, the bristles 46 (arrows R in
The free ends 58 of the bristles 46 extend through the drive shaft 40 and are commonly connected to a slide controller 60. As
The array of bristles 46 preferably includes one or more radiological markers 62, as previously described. The markers 62 allow radiologic visualization of the brush structure 44 while in use within the targeted treatment area. The controller 60 can also include indicia 64 by which the physician can visually estimate the bristle extension distance. The distal end 42 of the drive shaft 40 can also carry one or more markers 62.
The drive shaft 40 of the tool 38 is, in use, carried for axial and rotational movement within the guide sheath or cannula 34, in the same manner shown for the tool 10 in
The bristles 140 radially extend from the drive shaft 142, near its distal end. The bristles 140 can be made, e.g., from resilient stainless steel, or injection molded inert plastic, or shape memory material, like nickel titanium. The bristles 140 can, in cross section, be round, rectilinear, or an other configuration.
As
The proximal end of the drive shaft 142 carries a fitting 146 that, in use, is coupled to an electric motor 148. The motor 148 rotates the drive shaft 142 (arrow R in
As
In the illustrated embodiment, the drive shaft 142 carries a pitched blade 151 at its distal end. The blade 151 rotates with the drive shaft 142. By engaging tissue, the blade 151 generates a forward-pulling force, which helps to advance the drive shaft 142 and bristles 140 through the soft tissue mass.
In the illustrated embodiment, the bristles 140, or the cannula 144, or both include one or more radiological markers 153, as previously described. The markers 153 allow radiologic visualization of the bristles 140 while rotating and advancing within the targeted treatment area.
C. Rotatable Blade Structure
The distal end of the drive shaft 108 carries a cavity forming structure 110, which comprises a cutting blade. The blade 110 can take various shapes.
In
In
The material from which the blade 110 is made can be stainless steel, or injection molded inert plastic. The legs 112 and 116 of the blade 110 shown in
When rotated (arrow R), the blade 110 cuts a generally cylindrical path through surrounding tissue mass. The forward pitch of the blade 110 reduces torque and provides stability and control as the blade 110 advances, while rotating, through the tissue mass.
Rotation of the blade 110 can be accomplished manually or at higher speed by use of a motor. In the illustrated embodiment, the proximal end of the drive shaft 108 of the tool 106 carries a fitting 118. The fitting 118 is coupled to an electric motor 120 to rotate the drive shaft 108, and, with it, the blade 110.
As
The blade 110, or the end of the cannula 124, or both can carry one or more radiological markers 122, as previously described. The markers 122 allow radiologic visualization of the blade 110 and its position relative to the cannula 34 while in use within the targeted treatment area.
D. Rinsing and Aspiration
As
A rinsing liquid 136, e.g., sterile saline, can be introduced from the source 130 through the lumen 128 into the targeted tissue region as the tools 10, 38, or 106 rotate and cut the tissue mass TM. The rinsing liquid 136 reduces friction and conducts heat away from the tissue during the cutting operation. The rinsing liquid 136 can be introduced continuously or intermittently while the tissue mass is being cut. The rinsing liquid 136 can also carry an anticoagulant or other anti-clotting agent.
By periodically coupling the lumen 128 to the vacuum source 134, liquids and debris can be aspirated from the targeted tissue region through the lumen 128.
II. Linear Movement Cavity Forming Structures
A. Cutting Blade
FIGS. 17 to 21 show a linear movement tool 66 capable of forming a cavity in a targeted treatment area. Like the tool 10, the tool 66 comprises a catheter tube 68 having a handle 70 (see
The catheter tube 68 carries a linear movement cavity forming structure 74 at its distal end 76. In the illustrated embodiment, the structure 56 comprises a generally rigid blade 78, which projects at a side angle from the distal end 76 (see
A stylet 80 is carried by an interior track 82 within the catheter tube 68 (see
The far end of the stylet 80 is coupled to the blade 78. The near end of the stylet 80 carries a control knob 84. By rotating the control knob 84, the physician rotates the blade 78 between an at rest position, shown in
In use, the catheter tube 68 is also carried for sliding and rotation within the guide sheath or cannula 34, in the same manner shown in
The blade 78 can carry one or more radiological markers 86, as previously described, to allow radiologic visualization of the blade 78 within the targeted treatment area. Indicia 88 on the stylet 80 can also allow the physician to visually approximate the extent of linear or rotational movement of the blade 78. The distal end 76 of the catheter tube 68 can also carry one or more markers 86.
B. Energy Transmitters
However, for the tool 90 shown
The type of energy 100 that the transmitter 92 propagates to remove tissue in the targeted treatment area can vary. For example, the transmitter 92 can propagate ultrasonic energy at harmonic frequencies suitable for cutting the targeted tissue. Alternatively, the transmitter 92 can propagate laser energy at a suitable tissue cutting frequency.
As before described, the near end of the stylet 80 includes a control knob 84. Using the control knob 84, the physician is able to move the transmitter 92 in a linear path (arrows A and F in
As also described before, the catheter tube 68 of the tool 90 is, in use, carried for sliding and rotation within the guide sheath or cannula 34. The physician slides the catheter tube 68 axially within the guide sheath 34 for deployment of the tool 90 at the targeted treatment site. When deployed at the site, the physician operates the control knob 84 to linearly move and rotate the transmitter 92 to achieve a desired position in the targeted treatment area. The physician can also rotate the catheter tube 68 and thereby further adjust the location of the transmitter 92.
The transmitter 92 or stylet 80 can carry one or more radiological markers 86, as previously described, to allow radiologic visualization of the position of the transmitter 92 within the targeted treatment area. Indicia 88 on the stylet 80 can also allow the physician to visually estimate the position of the transmitter 92. The distal end 76 of the catheter tube 68 can also carry one or more markers 86.
III. Use of Cavity Forming Tools
Use of the various tools 10 (FIGS. 1 to 4), 38 (FIGS. 5 to 8) , 138 (FIGS. 9 to 11) , 106 (FIGS. 12 to 15), 66 (FIGS. 17 to 21), and 90 (
As
The vertebral body 152 is in the shape of an oval disk. As
Alternatively, access into the interior volume can be accomplished by drilling an access portal through either pedicle 164 (identified in
As
A. Deployment and Use of the Loop Tool in a Vertebral Body
When, for example, the loop tool 10 is used, the loop structure 20 is, if extended, collapsed by the guide sheath 34 (as shown in
Referring to
Synchronous rotation and operation of the controller 30 to enlarge the dimensions of the loop structure 20 during the procedure allows the physician to achieve a create a cavity C of desired dimension. Representative dimensions for a cavity C will be discussed in greater detail later.
B. Deployment and Use of the Brush Tool in a Vertebral Body
When, for example, the brush tool 38 is used, the physician preferable withdraws the bristles 46 during their passage through the guide sheath 34, in the manner shown in
Referring to
C. Deployment and Use of the Linear Tools in a Vertebral Body
When, for example, one of the linear movement tools 66 or 90 are used, the physician preferable withdraws the blade 78 or the transmitter 92 into the catheter tube 68 in the manner shown in
Referring to
Referring to
D. Deployment of Other Tools into the Cavity
Once the desired cavity C is formed, the selected tool 10, 38, 66, 90, 106, or 138 is withdrawn through the guide sheath 34. As
E. Bone Cavity Dimensions
The size of the cavity C varies according to the therapeutic or diagnostic procedure performed.
At least about 30% of the cancellous bone volume needs to be removed in cases where the bone disease causing fracture (or the risk of fracture) is the loss of cancellous bone mass (as in osteoporosis). The preferred range is about 30% to 90% of the cancellous bone volume. Removal of less of the cancellous bone volume can leave too much of the diseased cancellous bone at the treated site. The diseased cancellous bone remains weak and can later collapse, causing fracture, despite treatment.
However, there are times when a lesser amount of cancellous bone removal is indicated. For example, when the bone disease being treated is localized, such as in avascular necrosis, or where local loss of blood supply is killing bone in a limited area, the selected tool 10, 38, 66, 90, 106, or 138 can remove a smaller volume of total bone. This is because the diseased area requiring treatment is smaller.
Another exception lies in the use of a selected tool 10, 36, 66, 90, 106, or 138 to improve insertion of solid materials in defined shapes, like hydroxyapatite and components in total joint replacement. In these cases, the amount of tissue that needs to be removed is defined by the size of the material being inserted.
Yet another exception lays the use of a selected tool 10, 36, 66, 90, 106, or 138 in bones to create cavities to aid in the delivery of therapeutic substances, as disclosed in copending U.S. patent application Ser. No. 08/485,394. In this case, the cancellous bone may or may not be diseased or adversely affected. Healthy cancellous bone can be sacrificed by significant compaction to improve the delivery of a drug or growth factor which has an important therapeutic purpose. In this application, the size of the cavity is chosen by the desired amount of therapeutic substance sought to be delivered. In this case, the bone with the drug inside is supported while the drug works, and the bone heals through exterior casting or current interior or exterior fixation devices.
IV. Single Use Sterile Kit
A single use of any one of the tools 10, 38, 138, 106, 66, or 90 creates contact with surrounding cortical and cancellous bone. This contact can damage the tools, creating localized regions of weakness, which may escape detection. The existence of localized regions of weakness can unpredictably cause overall structural failure during a subsequent use.
In addition, exposure to blood and tissue during a single use can entrap biological components on or within the tools. Despite cleaning and subsequent sterilization, the presence of entrapped biological components can lead to unacceptable pyrogenic reactions.
As a result, following first use, the tools may not meet established performance and sterilization specifications. The effects of material stress and damage caused during a single use, coupled with the possibility of pyrogen reactions even after resterilization, reasonably justify imposing a single use restriction upon the tools for deployment in bone.
To protect patients from the potential adverse consequences occasioned by multiple use, which include disease transmission, or material stress and instability, or decreased or unpredictable performance, each single use tool 10, 38, 66, 90, 106, or 138 is packaged in a sterile kit 500 (see
As
The kit 500 includes an inner wrap 512, which is peripherally sealed by heat or the like, to enclose the tray 508 from contact with the outside environment. One end of the inner wrap 512 includes a conventional peal-away seal 514 (see
The kit 500 also includes an outer wrap 516, which is also peripherally sealed by heat or the like, to enclosed the inner wrap 512. One end of the outer wrap 516 includes a conventional peal-away seal 518 (see
Both inner and outer wraps 512 and 516 (see
The sterile kit 500 also carries a label or insert 506, which includes the statement “For Single Patient Use Only” (or comparable language) to affirmatively caution against reuse of the contents of the kit 500. The label 506 also preferably affirmatively instructs against resterilization of the tool 502. The label 506 also preferably instructs the physician or user to dispose of the tool 502 and the entire contents of the kit 500 upon use in accordance with applicable biological waste procedures. The presence of the tool 502 packaged in the kit 500 verifies to the physician or user that the tool 502 is sterile and has not be subjected to prior use. The physician or user is thereby assured that the tool 502 meets established performance and sterility specifications, and will have the desired configuration when expanded for use.
The kit 500 also preferably includes directions for use 524, which instruct the physician regarding the use of the tool 502 for creating a cavity in cancellous bone in the manners previously described. For example, the directions 524 instruct the physician to deploy and manipulate the tool 502 inside bone to cut cancellous bone and form a cavity. The directions 524 can also instruct the physician to fill the cavity with a material, e.g., bone cement, allograft material, synthetic bone substitute, a medication, or a flowable material that sets to a hardened condition.
The features of the invention are set forth in the following claims.
Claims
1. An assembly comprising
- a shaft member sized and configured for introduction through a percutaneous access path into a cancellous bone volume, the shaft having an elongated axis, and
- a cutting blade sized and configured to be carried by the shaft member and project radially outward of the elongated axis into contact with cancellous bone, the cutting blade being capable of cutting cancellous bone in a path about the elongated axis in response to rotation of the shaft member within cancellous bone.
2. An assembly according to claim 1
- further including a tool to convey a volume of bone filling material into cancellous bone cut by the cutting blade.
3. An assembly according to claim 1
- wherein the cutting blade comprises a metal material.
4. An assembly according to claim 1
- wherein the cutting blade comprises a plastic material.
5. A system according to claim 1
- wherein the cutting blade comprises a curved surface.
6. A system according to claim 1
- wherein the cutting blade defines at least a portion of a loop.
7. A system according to claim 1
- wherein the cutting blade comprises a round cross section.
8. A system according to claim 1
- wherein the cutting blade comprises a rectilinear cross section.
9. A system according to claim 1
- wherein the cutting blade is pitched relative to the elongated axis.
10. A system according to claim 1
- wherein at least a portion of the cutting blade is radiopaque.
11. A system according to claim 1
- wherein at least a portion of the cutting blade includes a material that permits remote visualization of the cutting blade.
12. A system according to claim 1
- wherein the path cut by the cutting blade forms, at least in part, a cavity.
13. A method comprising
- providing a tool comprising a shaft member having an elongated axis and a cutting blade carried by the shaft member and project radially outward of the elongated axis into contact with cancellous bone, the cutting blade being capable of cutting cancellous bone in a path about the elongated axis in response to rotation of the shaft member within cancellous bone,
- establishing a percutaneous access path leading into a cancellous bone volume,
- introducing the tool through the access path, and
- rotating the shaft to cut cancellous bone in a path about the elongated axis.
14. A method according to claim 13
- further including conveying a bone filling material into cancellous bone cut by the cutting blade.
15. A system according to claim 1
- wherein rotation of the shaft forms, at least in part, a cavity in cancellous bone.
Type: Application
Filed: Apr 24, 2007
Publication Date: Aug 23, 2007
Applicant:
Inventors: Mark Reiley (Piedmont, CA), Arie Scholten (Fremont, CA)
Application Number: 11/789,226
International Classification: A61B 17/00 (20060101);