US20050043737A1 - Structures for creating cavities in interior body regions - Google Patents

Abstract

A shaft having an axis and a distal end portion is adapted to be deployed inside a vertebral body through a cannula. A filament is carried by the distal end portion. A surface on the filament is movable between a collapsed condition sized and configured to be deployed with the shaft through the cannula and an extended position that extends radially from the shaft. A mechanism is coupled to the filament to extend the filament in situ radially from the shaft into contact with cancellous bone within the vertebral body. The surface, when extended, defines a structure capable of forming a cavity wholly within the vertebral body in the cancellous bone.

Description

RELATED APPLICATIONS
• This application is a divisional of application Ser. No. 10/208,391, filed Jul. 30, 2002 and entitled “Structures and Methods for Creating Cavities in Interior Body Regions,” which is a divisional of application Ser. No. 09/055,805, filed Apr. 6, 1998 (now U.S. Pat. No. 6,440,138).
FIELD OF THE INVENTION
• The 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 INVENTION
• Certain 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 INVENTION
• The invention provides a system comprising a cannula having an axis that establishes a percutaneous path leading into a vertebral body and a shaft having an axis and a distal end portion adapted to be deployed inside the vertebral body through the cannula. A filament carried by the distal end portion comprises a surface which is movable between a collapsed condition sized and configured to be deployed with the shaft through the cannula and an extended position that extends radially from the shaft. A mechanism is coupled to the filament to extend the filament in situ radially from the shaft into contact with cancellous bone within the vertebral body. The surface, when extended, defines a structure capable of forming a cavity wholly within the vertebral body in the 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
• FIG. 1 is a side view of a rotatable tool having a loop structure capable of forming a cavity in tissue, with the loop structure deployed beyond the associated catheter tube;
• FIG. 1A is an enlarged end view of the tool shown inFIG. 1;
• FIG. 2 is a side view of the tool shown inFIG. 1, with the loop structure retracted within the catheter tube;
• FIG. 3 is a side view of the tool shown inFIG. 1, with the loop structure deployed beyond the catheter tube to a greater extent than shown inFIG. 1;
• FIG. 4 is a side view of the tool shown inFIG. 1 inserted within a guide sheath for deployment in a targeted treatment area;
• FIG. 5 is a side view of another rotatable tool having a brush structure capable of forming a cavity in tissue, with the brush structure deployed beyond the associated drive tube;
• FIG. 5A is an enlarged end view of the tool shown inFIG. 5;
• FIG. 6 is a side view of the tool shown inFIG. 5, with the brush structure retracted within the drive tube;
• FIG. 7 is a side view of the tool shown inFIG. 5, with the brush structure deployed beyond the catheter tube to a greater extent than shown inFIG. 5, and with the brush structure being rotated to cause the associated bristles to flare outward;
• FIG. 8 is a side view of the tool shown inFIG. 7, with the brush structure deployed beyond the catheter tube to a greater extent than shown inFIG. 7, and with the brush structure still being rotated to cause the associated bristles to flare outward;
• FIG. 9 is a side view of an alternative tool having an array of bristles carried by a flexible shaft, which is capable of forming a cavity in tissue;
• FIG. 10 is a side view of the tool shown inFIG. 9 as it is being deployed inside a cannula;
• FIG. 11 is the tool shown inFIG. 9 when deployed in a soft tissue region bounded by hard tissue;
• FIG. 12 is a side view of a tool having a rotatable blade structure capable of forming a cavity in tissue;
• FIG. 13 is a side view of an alternative curved blade structure that the tool shown inFIG. 12 can incorporate;
• FIG. 14 is a side view of an alternative ring blade structure that the tool shown inFIG. 12 can incorporate;
• FIG. 15 is a side view of the ring blade structure shown inFIG. 14 while being introduced through a cannula;
• FIG. 16 is a side view of a rotating tool capable of forming a cavity in tissue, with an associated lumen to introduce a rinsing liquid and aspirate debris;
• FIG. 17 is a perspective side view of a tool having a linear movement blade structure capable of forming a cavity in tissue, with the blade structure deployed beyond the associated catheter tube in an operative position for use;
• FIG. 18 is an end view of the tool shown inFIG. 17, with the blade structure shown in its operative position for use;
• FIG. 19 is an end view of the tool shown inFIG. 17, with the blade structure shown in its rest position within the catheter tube;
• FIG. 20 is a side view of the tool shown inFIG. 17, with the blade structure shown in its rest position within the catheter tube, as also shown in an end view inFIG. 18;
• FIG. 21 is a side view of the tool shown inFIG. 17, with the blade structure deployed beyond the associated catheter tube in an operative position for use, as also shown in an end view inFIG. 18;
• FIG. 22 is a side view of a tool having a linear movement energy transmitter capable of forming a cavity in tissue, with the energy transmitter deployed beyond the associated catheter tube in an operative position for use;
• FIG. 23 is a top view of a human vertebra, with portions removed to reveal cancellous bone within the vertebral body, and with a guide sheath located for postero-lateral access;
• FIG. 24 is a side view of the vertebra shown inFIG. 23;
• FIG. 25 is a top view of the vertebra shown inFIG. 23, with the tool shown inFIG. 1 deployed to cut cancellous bone by rotating the loop structure, thereby forming a cavity;
• FIG. 26 is a top view of the vertebra shown inFIG. 23, with the tool shown inFIG. 5 deployed to cut cancellous bone by rotating the brush structure, thereby forming a cavity;
• FIG. 27 is a side view of the vertebra shown inFIG. 23, with the tool shown inFIG. 17 deployed to cut cancellous bone by moving the blade structure in a linear path, thereby forming a cavity;
• FIG. 28 is a side view of the vertebra shown inFIG. 23, with the tool shown inFIG. 22 deployed to cut cancellous bone using an energy transmitter, which is both rotatable and movable in a linear path, thereby forming a cavity;
• FIG. 29 is a side view of the vertebra shown inFIG. 23, after formation of a cavity by use of one of the tools shown in FIGS.25 to28, and with a second tool deployed to introduce material into the cavity for therapeutic purposes;
• FIG. 30 is a plan view of a sterile kit to store a single use cavity forming tool of a type previously shown; and
• FIG. 31 is an exploded perspective view of the sterile kit shown inFIG. 30.
• 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 EMBODIMENTS
• The 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
• FIG. 1 shows arotatable tool10 capable of forming a cavity in a targeted treatment area. Thetool10 comprises acatheter tube12 having a proximal and a distal end, respectively14 and16. Thecatheter tube12 preferable includes ahandle18 to aid in gripping and maneuvering thetube12. Thehandle18 can be made of a foam material secured about thecatheter tube12.
• Thecatheter tube12 carries acavity forming structure20 at itsdistal end16. In the illustrated embodiment, thestructure20 comprises afilament22 of resilient inert material, which is bent back upon itself and preformed with resilient memory to form a loop.
• The material from which thefilament22 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. Thefilament22 can, in cross section, be round, rectilinear, or an other configuration.
• AsFIG. 1A shows, thefilament22 radiates fromslots24 in a base26 carried by thedistal end16 of thecatheter tube12. The free ends28 of thefilament22 extend through thecatheter tube12 and are connected to aslide controller30 near thehandle18.
• AsFIG. 2 shows, sliding thecontroller30 aft (arrow A) retracts thefilament22 through theslots24, which progressively decreases the dimensions of theloop structure20. AsFIG. 2 shows, in its farthest aft position, thefilament22 is essentially fully withdrawn and does not project a significant distance beyond thedistal end16 of thecatheter tube12.
• AsFIG. 3 shows, sliding thecontroller30 forward (arrow F) advances thefilament22 through theslots24. Theloop structure20 forms, which projects beyond thedistal end16 of thecatheter tube12. As it is advanced progressively forward through theslots24, the dimensions of theloop structure20 progressively increase (compareFIG. 1 toFIG. 3). Thecontroller30 can includeindicia32, through which the physician can estimate the dimensions of theloop structure20.
• In use (seeFIG. 4), thecatheter tube12 is carried for axial and rotational movement within a guide sheath orcannula34. The physician is able to freely slide thecatheter tube12 axially within the guide sheath34 (arrow S inFIG. 4). AsFIG. 4 shows, when fully confined by theguide sheath34, theloop structure20, if projecting a significant distance beyond thedistal end16, is collapsed by the surroundingsheath34. When free of theguide sheath34, theloop structure20 springs open to assume its normal dimension. Thereafter, the physician can operate thecontroller30 to alter the dimension of theloop structure20 at will.
• When free of theguide sheath34, the physician is also able to rotate the deployedloop structure20, by rotating thecatheter tube12 within the guide sheath34 (arrow R inFIG. 4). As will be described in greater detail alter, rotation of theloop structure20 slices or cut through surrounding tissue mass.
• The materials for thecatheter tube12 are selected to facilitate advancement and rotation of theloop structure20. Thecatheter tube12 can be constructed, for example, using standard flexible, medical grade plastic materials, like vinyl, nylon, polyethylenes, ionomer, polyurethane, and polyethylene tetraphthalate (PET). Thecatheter tube12 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.
• Thefilament22 preferably carries one or moreradiological markers36. Themarkers36 are made from known radiopaque materials, like platinum, gold, calcium, tantalum, and other heavy metals. At least onemarker36 is placed at or near the distal extremity of theloop structure20, while other markers can be placed at spaced apart locations on theloop structure20. Thedistal end16 of thecatheter tube12 can also carry markers. Themarkers36 permit radiologic visualization of theloop structure20 andcatheter tube12 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 theloop structure20 within the targeted treatment area.
• B. Rotatable Brush
• FIG. 5 shows an alternative embodiment of arotatable tool38 capable of forming a cavity in a targeted treatment area. Thetool38 comprises adrive shaft40, which is made from stiffer materials for good torsion transmission capabilities, e.g., stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys.
• Thedistal end42 of the drive shaft carries acavity forming structure44, which comprises an array offilaments forming bristles46. AsFIG. 5A shows, thebristles46 extend from spaced-apartslots48 in a base50 carried by thedistal end42 of thedrive shaft40.
• The material from which thebristles46 is made can be stainless steel, or injection molded inert plastic, or shape memory material, like nickel titanium. Thebristles46 can, in cross section, be round, rectilinear, or an other configuration.
• Theproximal end52 of thedrive shaft40 carries a fitting54 that, in use, is coupled to anelectric motor56 for rotating thedrive shaft40, and, with it, the bristles46 (arrows R inFIGS. 7 and 8). When rotated by themotor46, the bristles spread apart (asFIG. 7 shows), under the influence of centrifugal force, forming a brush-like structure44. Thebrush structure44, when rotating, cuts surrounding tissue mass in the targeted treatment area.
• The free ends58 of thebristles46 extend through thedrive shaft40 and are commonly connected to aslide controller60. AsFIG. 6 shows, sliding thecontroller60 aft (arrow A inFIG. 6) shortens the distance thebristles46 extend from thebase50. AsFIGS. 7 and 8 show, sliding thecontroller60 forward (arrow F inFIG. 8) lengthens the extension distance of thebristles46. Using thecontroller60, the physician is able to adjust the dimension of the cutting area (compareFIG. 7 andFIG. 8).
• The array ofbristles46 preferably includes one or moreradiological markers62, as previously described. Themarkers62 allow radiologic visualization of thebrush structure44 while in use within the targeted treatment area. Thecontroller60 can also includeindicia64 by which the physician can visually estimate the bristle extension distance. Thedistal end42 of thedrive shaft40 can also carry one ormore markers62.
• Thedrive shaft40 of thetool38 is, in use, carried for axial and rotational movement within the guide sheath orcannula34, in the same manner shown for thetool10 in Fig,4. The physician is able to freely slide thedrive shaft40 axially within the guide sheath to deploy it in the targeted treatment area. Once connected to thedrive motor56, thedrive shaft40 is free to rotate within theguide sheath34 to form thebrush structure44.
• FIG. 9 shows an alternative embodiment of arotatable tool138 having an array offilaments forming bristles140, which is capable of forming a cavity in a targeted treatment area. Thetool138 includes aflexible drive shaft142, which is made, e.g., from twisted wire filaments, such stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys.
• Thebristles140 radially extend from thedrive shaft142, near its distal end. Thebristles140 can be made, e.g., from resilient stainless steel, or injection molded inert plastic, or shape memory material, like nickel titanium. Thebristles140 can, in cross section, be round, rectilinear, or an other configuration.
• AsFIG. 10 shows, thetool138 is introduced into the targeted tissue region through acannula144. When in thecannula144, theresilient bristles140 are compressed rearward to a low profile, enabling passage through the cannula. When free of thecannula144, theresilient bristles140 spring radially outward, ready for use.
• The proximal end of thedrive shaft142 carries a fitting146 that, in use, is coupled to anelectric motor148. Themotor148 rotates the drive shaft142 (arrow R inFIG. 11), and, with it, thebristles140.
• AsFIG. 11 shows, when deployed inside an interior body cavity with soft tissue S (e.g., cancellous bone bounded by hard tissue H (e.g., cortical bone), the physician can guide thetool138 through the soft tissue S by allowing the rotatingbristles140 to ride against the adjoining hard tissue H. Theflexible drive shaft142 bends to follow the contour of the hard tissue H, while the rotatingbristles140 cut adjoining soft tissue S, forming a cavity C.
• In the illustrated embodiment, thedrive shaft142 carries a pitchedblade151 at its distal end. Theblade151 rotates with thedrive shaft142. By engaging tissue, theblade151 generates a forward-pulling force, which helps to advance thedrive shaft142 and bristles140 through the soft tissue mass.
• In the illustrated embodiment, thebristles140, or thecannula144, or both include one or moreradiological markers153, as previously described. Themarkers153 allow radiologic visualization of thebristles140 while rotating and advancing within the targeted treatment area.
• C. Rotatable Blade Structure
• FIG. 12 shows an alternative embodiment of arotatable tool106 capable of forming a cavity in a targeted treatment area. Thetool106, like thetool38, comprises a generallystiff drive shaft108, made from, e.g., stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys, for good torsion transmission capabilities.
• The distal end of thedrive shaft108 carries acavity forming structure110, which comprises a cutting blade. Theblade110 can take various shapes.
• InFIGS. 12 and 13, theblade110 is generally L-shaped, having amain leg112 and ashort leg116. In the illustrated embodiment, themain leg112 of theblade110 is pitched radially forward of thedrive shaft axis114, at a small forward angle beyond perpendicular to the drive shaft. Themain leg112 may possess a generally straight configuration (asFIG. 12 shows), or, alternatively, it may present a generally curved surface (asFIG. 13 shows). In the illustrated embodiment, theshort leg116 of theblade110 is also pitched at a small forward angle from themain leg112, somewhat greater than perpendicular.
• InFIG. 14, theblade110 takes the shape of acontinuous ring126. As illustrated, thering126 is pitched slightly forward, e.g., at an angle slightly greater than perpendicular relative to thedrive shaft axis114.
• The material from which theblade110 is made can be stainless steel, or injection molded inert plastic. Thelegs112 and116 of theblade110 shown in FIGS.12 and13, and thering126 shown inFIG. 14, can, in cross section, be round, rectilinear, or an other configuration.
• When rotated (arrow R), theblade110 cuts a generally cylindrical path through surrounding tissue mass. The forward pitch of theblade110 reduces torque and provides stability and control as theblade110 advances, while rotating, through the tissue mass.
• Rotation of theblade110 can be accomplished manually or at higher speed by use of a motor. In the illustrated embodiment, the proximal end of thedrive shaft108 of thetool106 carries a fitting118. The fitting118 is coupled to anelectric motor120 to rotate thedrive shaft108, and, with it, theblade110.
• AsFIG. 15 shows, thedrive shaft108 of thetool108 is deployed subcutaneously into the targeted tissue area through a guide sheath orcannula124. Connected to thedrive motor120, thedrive shaft108 rotates within theguide sheath34, thereby rotating theblade110 to cut a cylindrical path P in the surrounding tissue mass TM. Theblade110 can be advanced and retracted, while rotating, in a reciprocal path (arrows F and A), by applying pushing and pulling forces upon thedrive shaft108. Theblade110 can also be withdrawn into thecannula124 to allow changing of the orientation of thecannula124. In this way, successive cylindrical paths can be cut through the tissue mass, through rotating and reciprocating theblade110, to thereby create a desired cavity shape.
• Theblade110, or the end of thecannula124, or both can carry one or moreradiological markers122, as previously described. Themarkers122 allow radiologic visualization of theblade110 and its position relative to thecannula34 while in use within the targeted treatment area.
• D. Rinsing and Aspiration
• AsFIG. 16 shows, any of thetools10,38,106, or138 can include aninterior lumen128. Thelumen128 is coupled via a Y-valve132 to aexternal source130 of fluid and anexternal vacuum source134.
• A rinsingliquid136, e.g., sterile saline, can be introduced from thesource130 through thelumen128 into the targeted tissue region as thetools10,38, or106 rotate and cut the tissue mass TM. The rinsingliquid136 reduces friction and conducts heat away from the tissue during the cutting operation. The rinsing liquid136 can be introduced continuously or intermittently while the tissue mass is being cut. The rinsing liquid136 can also carry an anticoagulant or other anti-clotting agent.
• By periodically coupling thelumen128 to thevacuum source134, liquids and debris can be aspirated from the targeted tissue region through thelumen128.
• II. Linear Movement Cavity Forming Structures
• A. Cutting Blade
• FIGS.17 to21 show alinear movement tool66 capable of forming a cavity in a targeted treatment area. Like thetool10, thetool66 comprises acatheter tube68 having a handle70 (seeFIG. 20) on itsproximal end72 to facilitate gripping and maneuvering thetube68.
• Thecatheter tube68 carries a linear movementcavity forming structure74 at itsdistal end76. In the illustrated embodiment, thestructure56 comprises a generallyrigid blade78, which projects at a side angle from the distal end76 (seeFIGS. 17 and 21). Theblade78 can be formed from stainless steel or cast or molded plastic.
• Astylet80 is carried by aninterior track82 within the catheter tube68 (seeFIGS. 18 and 19). Thetrack82 extends along the axis of thecatheter tube68. Thestylet80 is free to move in a linear aft path (arrow A inFIG. 20) and a linear forward path (arrow F inFIG. 21) within thetrack82. Thestylet80 is also free to rotate within the track82 (arrow R inFIG. 17).
• The far end of thestylet80 is coupled to theblade78. The near end of thestylet80 carries acontrol knob84. By rotating thecontrol knob84, the physician rotates theblade78 between an at rest position, shown inFIGS. 19 and 20, and an operating position, shown inFIGS. 17, 18, and21. When in the at rest position, the physician can push or pull upon thecontrol knob84 to move theblade78 in a linear path within the catheter tube (seeFIG. 20). By pushing on thecontrol knob84, the physician can move theblade78 outside thecatheter tube68, where it can be rotated into the operating condition (seeFIG. 21). When in the operating position, pushing and pulling on thecontrol knob84 moves the blade in linear strokes against surrounding tissue mass.
• In use, thecatheter tube68 is also carried for sliding and rotation within the guide sheath orcannula34, in the same manner shown inFIG. 4. The physician is able to freely slide thecatheter tube68 axially within theguide sheath34 to deploy thetool66 in the targeted treatment site. When deployed at the site, the physician can deploy theblade78 in the operating condition outside thecatheter tube68 and slide theblade78 along tissue in a linear path. Linear movement of theblade78 along tissue cuts the tissue. The physician is also able to rotate both thecatheter tube68 within theguide sheath34 and theblade78 within thecatheter tube68 to adjust the orientation and travel path of theblade78.
• Theblade78 can carry one or moreradiological markers86, as previously described, to allow radiologic visualization of theblade78 within the targeted treatment area.Indicia88 on thestylet80 can also allow the physician to visually approximate the extent of linear or rotational movement of theblade78. Thedistal end76 of thecatheter tube68 can also carry one ormore markers86.
• B. Energy Transmitters
• Fig.22 shows an alternative embodiment of alinear movement tool90 capable of forming a cavity in a targeted treatment area. Thetool90 is physically constructed in the same way as thelinear movement tool66 just described, so common reference numerals are assigned.
• However, for thetool90 shownFIG. 22, the far end of thestylet80 carries, not acutting blade78, but instead atransmitter92 capable of transmitting energy that cuts tissue (shown bylines100 inFIG. 22). Aconnector94 couples thetransmitter92 to asource96 of the energy, through asuitable energy controller98.
• The type ofenergy100 that thetransmitter92 propagates to remove tissue in the targeted treatment area can vary. For example, thetransmitter92 can propagate ultrasonic energy at harmonic frequencies suitable for cutting the targeted tissue. Alternatively, thetransmitter92 can propagate laser energy at a suitable tissue cutting frequency.
• As before described, the near end of thestylet80 includes acontrol knob84. Using thecontrol knob84, the physician is able to move thetransmitter92 in a linear path (arrows A and F inFIG. 22) between a retracted position, housed with the catheter tube68 (like theblade78 shown inFIG. 20), and a range of extended positions outside thecatheter tube68, as shown inFIG. 22).
• As also described before, thecatheter tube68 of thetool90 is, in use, carried for sliding and rotation within the guide sheath orcannula34. The physician slides thecatheter tube68 axially within theguide sheath34 for deployment of thetool90 at the targeted treatment site. When deployed at the site, the physician operates thecontrol knob84 to linearly move and rotate thetransmitter92 to achieve a desired position in the targeted treatment area. The physician can also rotate thecatheter tube68 and thereby further adjust the location of thetransmitter92.
• Thetransmitter92 orstylet80 can carry one or moreradiological markers86, as previously described, to allow radiologic visualization of the position of thetransmitter92 within the targeted treatment area.Indicia88 on thestylet80 can also allow the physician to visually estimate the position of thetransmitter92. Thedistal end76 of thecatheter tube68 can also carry one ormore markers86.
• III. Use of Cavity Forming Tools
• Use of the various tools10 (FIGS.1 to4),38 (FIGS.5 to8),138 (FIGS.9 to11),106 (FIGS.12 to15),66 (FIGS.17 to21), and90 (FIG. 22) will now be described in the context of deployment in ahuman vertebra150.
• FIG. 23 shows thevertebra150 in coronal (top) view, andFIG. 24 shows thevertebra150 in lateral (side) view. It should be appreciated, however, the tool is not limited in its application to vertebrae. Thetools10,38,138,106,66, and90 can be deployed equally as well in long bones and other bone types.
• AsFIGS. 23 and 24 show, thevertebra150 includes avertebral body152, which extends on the anterior (i.e., front or chest) side of thevertebra150. Thevertebral body152 includes an exterior formed from compactcortical bone158. Thecortical bone158 encloses an interior volume of reticulated cancellous, or spongy, bone160 (also called medullary bone or trabecular bone).
• Thevertebral body152 is in the shape of an oval disk. AsFIGS. 23 and 24 show, access to the interior volume of thevertebral body152 can be achieved. e.g., by drilling anaccess portal162 through a side of thevertebral body152, which is called a postero-lateral approach. The portal162 for the postero-lateral approach enters at a posterior side of thebody152 and extends at angle forwardly toward the anterior of thebody152. The portal162 can be performed either with a closed, minimally invasive procedure or with an open procedure.
• Alternatively, access into the interior volume can be accomplished by drilling an access portal through either pedicle164 (identified inFIG. 23). This is called a transpedicular approach. It is the physician who ultimately decides which access site is indicated.
• AsFIGS. 23 and 24 show, the guide sheath34 (earlier shown inFIG. 4) is located in theaccess portal162. Under radiologic or CT monitoring, a selected one of thetools10,38,66, or90 can be introduced through theguide sheath34.
• A. Deployment and Use of the Loop Tool in a Vertebral Body
• When, for example, theloop tool10 is used, theloop structure20 is, if extended, collapsed by the guide sheath34 (as shown inFIG. 4), or otherwise retracted within the catheter tube12 (asFIG. 2 shows) during passage through theguide sheath34.
• Referring toFIG. 25, when theloop tool10 is deployed outside theguide sheath34 in thecancellous bone160, the physician operates thecontroller30 in the manner previously described to obtain a desired dimension for theloop structure20, which can be gauged by radiologic monitoring using the on-board markers36. The physician manually rotates theloop structure20 through surrounding cancellous bone160 (as indicated by arrows R inFIG. 25). Therotating loop structure20 cutscancellous bone160 and thereby forms a cavity C.A suction tube102, also deployed through theguide sheath34, removes cancellous bone cut by theloop structure20. Alternatively, thecatheter tube12 can include an interior lumen128 (as shown inFIG. 16) to serve as a suction tube as well as to convey a rinsing liquid into the cavity as it is being formed.
• Synchronous rotation and operation of thecontroller30 to enlarge the dimensions of theloop structure20 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, thebrush tool38 is used, the physician preferable withdraws thebristles46 during their passage through theguide sheath34, in the manner shown inFIG. 6.
• Referring toFIG. 26, when thebrush tool38 is deployed incancellous bone160 free of theguide sheath34, the physician advances the bristles46 a desired distance (as shown inFIG. 5), aided by radiologic monitoring of themarkers62, or theindicia32 previously described, or both. The physician connects thedrive shaft40 to themotor56 to rotate thebristles46, creating thebrush structure44. AsFIG. 26 shows, the rotatingbrush structure44 cutscancellous bone160 and forms a cavity C. The suction tube102 (or alumen128 in thedrive shaft40, as shown inFIG. 16) introduces a rinsing fluid (with an anticoagulant, if desired) and removes cancellous bone cut by thebrush structure44. By periodically stopping rotation of thebrush structure44 and operating the controller60 (previously described) to increase the forward extension of thebristles46, the physician able over time to create a cavity C having the desired dimensions.
• C. Deployment and use of the Linear Tools in a Vertebral Body
• When, for example, one of thelinear movement tools66 or90 are used, the physician preferable withdraws theblade78 or thetransmitter92 into thecatheter tube68 in the manner shown inFIG. 20, until thedistal end76 of thecatheter tube68 is free of theguide sheath34.
• Referring toFIG. 27, using theblade tool66, the physician operates thestylet80 forward (arrow F) and aft (arrow A) to move theblade78 in a linear path throughcancellous bone160. Theblade78 scrapes loose and cutscancellous bone160 along its path, which thesuction tube102 removes. A cavity C is thereby formed. Synchronous rotation (arrow R) and linear movement (arrows F and A) of theblade78 allow the physician to create a cavity C having a desired dimension.
• Referring toFIG. 28, using theenergy transmitting tool90, the physician rotates (arrow R) and pushes or pulls upon the stylet80 (arrows F and A) to position theenergy transmitter92 at desired locations incancellous bone160. Themarkers86 aid the location process. Transmission by thetransmitter92 of the selected energy cutscancellous bone160 for removal by thesuction tube102. A cavity C is thereby formed. Through purposeful maneuvering of thetransmitter92, the physician achieves a cavity C having the desired dimension.
• D. Deployment of Other Tools into the Cavity
• Once the desired cavity C is formed, the selectedtool10,38,66,90,106, or138 is withdrawn through theguide sheath34. AsFIG. 29 shows, another tool104 can now be deployed through theguide sheath34 into the formed cavity C. Thesecond tool104 can, for example, perform a diagnostic procedure. Alternatively, thesecond tool104 can perform a therapeutic procedure, e.g., by dispensing amaterial106 into the cavity C, such as, e.g., bone cement, allograft material, synthetic bone substitute, a medication, or a flowable material that sets to a hardened condition. Further details of the injection ofsuch materials106 into the cavity C for therapeutic purposes are found in U.S. Pat. Nos. 4,969,888 and 5,108,404 and in copending U.S. Pat. application Ser. No. 08/485,394, which are incorporated herein by reference.
• 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 selectedtool10,38,66,90,106, or138 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 selectedtool10,36,66,90,106, or138 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 selectedtool10,36,66,90,106, or138 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 thetools10,38,138,106,66, or90 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, eachsingle use tool10,38,66,90,106, or138 is packaged in a sterile kit500 (seeFIGS. 30 and 31) prior to deployment in bone.
• AsFIGS. 30 and 31 show, thekit500 includes aninterior tray508. Thetray508 holds the particular cavity forming tool (generically designated502) in a lay-flat, straightened condition during sterilization and storage prior to its first use. Thetray508 can be formed from die cut cardboard or thermoformed plastic material. Thetray508 includes one or more spaced aparttabs510, which hold thetool502 in the desired lay-flat, straightened condition.
• Thekit500 includes aninner wrap512, which is peripherally sealed by heat or the like, to enclose thetray508 from contact with the outside environment. One end of theinner wrap512 includes a conventional peal-away seal514 (seeFIG. 31), to provide quick access to thetray508 upon instance of use, which preferably occurs in a sterile environment, such as within an operating room.
• Thekit500 also includes anouter wrap516, which is also peripherally sealed by heat or the like, to enclosed theinner wrap512. One end of theouter wrap516 includes a conventional peal-away seal518 (seeFIG. 31), to provide access to theinner wrap512, which can be removed from theouter wrap516 in anticipation of imminent use of thetool502, without compromising sterility of thetool502 itself.
• Both inner andouter wraps512 and516 (seeFIG. 31) each includes a peripherally sealedtop sheet520 andbottom sheet522. In the illustrated embodiment, thetop sheet520 is made of transparent plastic film, like polyethylene or MYLAR™ material, to allow visual identification of the contents of thekit500. Thebottom sheet522 is made from a material that is permeable to EtO sterilization gas, e.g., TYVEC™ plastic material (available from DuPont).
• Thesterile kit500 also carries a label or insert506, which includes the statement “For Single Patient Use Only” (or comparable language) to affirmatively caution against reuse of the contents of thekit500. Thelabel506 also preferably affirmatively instructs against resterilization of thetool502. Thelabel506 also preferably instructs the physician or user to dispose of thetool502 and the entire contents of thekit500 upon use in accordance with applicable biological waste procedures. The presence of thetool502 packaged in thekit500 verifies to the physician or user that thetool502 is sterile and has not be subjected to prior use. The physician or user is thereby assured that thetool502 meets established performance and sterility specifications, and will have the desired configuration when expanded for use.
• Thekit500 also preferably includes directions foruse524, which instruct the physician regarding the use of thetool502 for creating a cavity in cancellous bone in the manners previously described. For example, thedirections524 instruct the physician to deploy and manipulate thetool502 inside bone to cut cancellous bone and form a cavity. Thedirections524 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 (5)

1. A system comprising

a cannula having an axis that establishes a percutaneous path leading into a vertebral body,

a shaft having an axis and a distal end portion adapted to be deployed inside the vertebral body through the cannula,

a filament carried by the distal end portion comprising a surface which is movable between a collapsed condition sized and configured to be deployed with the shaft through the cannula and an extended position that extends radially from the shaft, and

a mechanism coupled to the filament to extend the filament in situ radially from the shaft into contact with cancellous bone within the vertebral body, the surface, when extended, defining a structure capable of forming a cavity wholly within the vertebral body in the cancellous bone.

2. A system according toclaim 1, further including

a tool to convey a filling material into the cavity.

3. A system according toclaim 1

wherein the surface carries at least one marker to aid visualizing the structure inside bone.

4. A system according toclaim 1 wherein the structure, when extended, is deployed at an axis that transverses the axis of the shaft.

5. A system according toclaim 1

wherein the shaft is flexible.

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