PATENT ABSTRACT
Systems and method create a cavity in cancellous bone by use of a system or kit that includes a cannula having an axis that establishes a percutaneous path leading into bone and a shaft having a distal end portion carrying an elongated loop structure or bristles capable of extension from the shaft to create a cavity forming structure. The shaft is movable relative to the axis of the cannula to move the cavity forming structure when extended within cancellous bone to form a cavity in the cancellous bone. A tool is sized for passage through the cannula. The tool is capable of dispensing a filling material into the cavity.

PATENT DESCRIPTION
RELATED APPLICATIONS 
     This application is a divisional of application Ser. No. 11/789,226, filed Apr. 24, 2007, and entitled Apparatus and Methods for Creating Cavities in Interior Body Regions,” which 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,” (now abandoned), 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 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 
     One aspect of the invention provides systems and methods for creating a cavity in cancellous bone. The systems and method comprise a cannula having an axis that establishes a percutaneous path leading into bone. The systems and method include a shaft having a distal end portion carrying an elongated loop structure or bristles capable of extension from the shaft to create a cavity forming structure. The shaft is sized for passage through the cannula into bone prior to extension of the elongated loop structure or bristles. The systems and methods include a controller to extend the elongated loop structure or bristles from the shaft in situ within cancellous bone to create the cavity forming structure. The shaft is movable relative to the axis of the cannula to move the cavity forming structure when extended within cancellous bone to form a cavity in the cancellous bone. The systems and methods include a tool sized for passage through the cannula, the tool being capable of dispensing a filling material into the cavity. 
     Another aspect of the invention provides a kit comprising a cannula having an axis that establishes a percutaneous path leading into bone and a shaft having a distal end portion carrying an elongated loop structure or bristles capable of extension from the shaft to create a cavity forming structure. The shaft is sized for passage through the cannula into bone prior to extension of the elongated loop structure or bristles. The kit includes a controller to extend the elongated loop structure or bristles from the shaft in situ within cancellous bone to create the cavity forming structure. The shaft is movable relative to the axis of the cannula to move the cavity forming structure when extended within cancellous bone to form a cavity in the cancellous bone. The kit includes a tool sized for passage through the cannula, the tool being capable of dispensing a filling material into the cavity. The kit includes instructions for creating a cavity in cancellous bone by deploying the cannula percutaneously to establish a path leading into bone, introducing the shaft by movement within and along the axis of the cannula to place the elongated loop structure or bristles inside cancellous bone, extending the cavity forming structure in situ within the cancellous bone from the shaft, moving the shaft to form a cavity in the cancellous bone, and introducing the tool by movement within and along the axis of the cannula, and conveying filling material through the tool into the cavity. 
     Another aspect of the invention provides media comprising instructions for creating a cavity in cancellous bone by deploying a cannula having an axis that establishes a percutaneous path leading into bone, introducing a shaft having a distal end portion carrying an elongated loop structure or bristles capable of extension from the shaft to create a cavity forming structure, by movement of the shaft within and along the axis of the cannula to place the elongated loop structure or bristles inside cancellous bone, extending the cavity forming structure in situ within the cancellous bone from the shaft, moving the shaft to form a cavity in the cancellous bone, and introducing a tool a tool sized for passage through the cannula, the tool being capable of dispensing a filling material into the cavity, by movement of the tool within and along the axis of the cannula, and conveying filling material through the tool into the cavity. 
     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 in  FIG. 1 ; 
         FIG. 2  is a side view of the tool shown in  FIG. 1 , with the loop structure retracted within the catheter tube; 
         FIG. 3  is a side view of the tool shown in  FIG. 1 , with the loop structure deployed beyond the catheter tube to a greater extent than shown in  FIG. 1 ; 
         FIG. 4  is a side view of the tool shown in  FIG. 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 in  FIG. 5 ; 
         FIG. 6  is a side view of the tool shown in  FIG. 5 , with the brush structure retracted within the drive tube; 
         FIG. 7  is a side view of the tool shown in  FIG. 5 , with the brush structure deployed beyond the catheter tube to a greater extent than shown in  FIG. 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 in  FIG. 7 , with the brush structure deployed beyond the catheter tube to a greater extent than shown in  FIG. 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 in  FIG. 9  as it is being deployed inside a cannula; 
         FIG. 11  is the tool shown in  FIG. 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 in  FIG. 12  can incorporate; 
         FIG. 14  is a side view of an alternative ring blade structure that the tool shown in  FIG. 12  can incorporate; 
         FIG. 15  is a side view of the ring blade structure shown in  FIG. 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 in  FIG. 17 , with the blade structure shown in its operative position for use; 
         FIG. 19  is an end view of the tool shown in  FIG. 17 , with the blade structure shown in its rest position within the catheter tube; 
         FIG. 20  is a side view of the tool shown in  FIG. 17 , with the blade structure shown in its rest position within the catheter tube, as also shown in an end view in  FIG. 18 ; 
         FIG. 21  is a side view of the tool shown in  FIG. 17 , with the blade structure deployed beyond the associated catheter tube in an operative position for use, as also shown in an end view in  FIG. 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 in  FIG. 23 ; 
         FIG. 25  is a top view of the vertebra shown in  FIG. 23 , with the tool shown in  FIG. 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 in  FIG. 23 , with the tool shown in  FIG. 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 in  FIG. 23 , with the tool shown in  FIG. 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 in  FIG. 23 , with the tool shown in  FIG. 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 in  FIG. 23 , after formation of a cavity by use of one of the tools shown in  FIGS. 25 to 28 , 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 in  FIG. 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 a rotatable tool  10  capable of forming a cavity in a targeted treatment area. The tool  10  comprises a catheter tube  12  having a proximal and a distal end, respectively  14  and  16 . The catheter tube  12  preferable includes a handle  18  to aid in gripping and maneuvering the tube  12 . The handle  18  can be made of a foam material secured about the catheter tube  12 . 
     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  FIG. 1A  shows, the filament  22  radiates from slots  24  in a base  26  carried by the distal end  16  of the catheter tube  12 . The free ends  28  of the filament  22  extend through the catheter tube  12  and are connected to a slide controller  30  near the handle  18 . 
     As  FIG. 2  shows, sliding the controller  30  aft (arrow A) retracts the filament  22  through the slots  24 , which progressively decreases the dimensions of the loop structure  20 . As  FIG. 2  shows, in its farthest aft position, the filament  22  is essentially fully withdrawn and does not project a significant distance beyond the distal end  16  of the catheter tube  12 . 
     As  FIG. 3  shows, sliding the controller  30  forward (arrow F) advances the filament  22  through the slots  24 . The loop structure  20  forms, which projects beyond the distal end  16  of the catheter tube  12 . As it is advanced progressively forward through the slots  24 , the dimensions of the loop structure  20  progressively increase (compare  FIG. 1  to  FIG. 3 ). The controller  30  can include indicia  32 , through which the physician can estimate the dimensions of the loop structure  20 . 
     In use (see  FIG. 4 ), the catheter tube  12  is carried for axial and rotational movement within a guide sheath or cannula  34 . The physician is able to freely slide the catheter tube  12  axially within the guide sheath  34  (arrow S in  FIG. 4 ). As  FIG. 4  shows, when fully confined by the guide sheath  34 , the loop structure  20 , if projecting a significant distance beyond the distal end  16 , is collapsed by the surrounding sheath  34 . When free of the guide sheath  34 , the loop structure  20  springs open to assume its normal dimension. Thereafter, the physician can operate the controller  30  to alter the dimension of the loop structure  20  at will. 
     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  FIG. 4 ). As will be described in greater detail alter, rotation of the loop structure  20  slices or cut through surrounding tissue mass. 
     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 
       FIG. 5  shows an alternative embodiment of a rotatable tool  38  capable of forming a cavity in a targeted treatment area. The tool  38  comprises a drive shaft  40 , which is made from stiffer materials for good torsion transmission capabilities, e.g., stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys. 
     The distal end  42  of the drive shaft carries a cavity forming structure  44 , which comprises an array of filaments forming bristles  46 . As  FIG. 5A  shows, the bristles  46  extend from spaced-apart slots  48  in a base  50  carried by the distal end  42  of the drive shaft  40 . 
     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  FIGS. 7 and 8 ). When rotated by the motor  46 , the bristles spread apart (as  FIG. 7  shows), under the influence of centrifugal force, forming a brush-like structure  44 . The brush structure  44 , when rotating, cuts surrounding tissue mass in the targeted treatment area. 
     The free ends  58  of the bristles  46  extend through the drive shaft  40  and are commonly connected to a slide controller  60 . As  FIG. 6  shows, sliding the controller  60  aft (arrow A in  FIG. 6 ) shortens the distance the bristles  46  extend from the base  50 . As  FIGS. 7 and 8  show, sliding the controller  60  forward (arrow F in  FIG. 8 ) lengthens the extension distance of the bristles  46 . Using the controller  60 , the physician is able to adjust the dimension of the cutting area (compare  FIG. 7  and  FIG. 8 ). 
     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  FIG. 4 . The physician is able to freely slide the drive shaft  40  axially within the guide sheath to deploy it in the targeted treatment area. Once connected to the drive motor  56 , the drive shaft  40  is free to rotate within the guide sheath  34  to form the brush structure  44 . 
       FIG. 9  shows an alternative embodiment of a rotatable tool  138  having an array of filaments forming bristles  140 , which is capable of forming a cavity in a targeted treatment area. The tool  138  includes a flexible drive shaft  142 , which is made, e.g., from twisted wire filaments, such stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys. 
     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  FIG. 10  shows, the tool  138  is introduced into the targeted tissue region through a cannula  144 . When in the cannula  144 , the resilient bristles  140  are compressed rearward to a low profile, enabling passage through the cannula. When free of the cannula  144 , the resilient bristles  140  spring radially outward, ready for use. 
     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  FIG. 11 ), and, with it, the bristles  140 . 
     As  FIG. 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 the tool  138  through the soft tissue S by allowing the rotating bristles  140  to ride against the adjoining hard tissue H. The flexible drive shaft  142  bends to follow the contour of the hard tissue H, while the rotating bristles  140  cut adjoining soft tissue S, forming a cavity C. 
     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 
       FIG. 12  shows an alternative embodiment of a rotatable tool  106  capable of forming a cavity in a targeted treatment area. The tool  106 , like the tool  38 , comprises a generally stiff drive shaft  108 , made from, e.g., stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys, for good torsion transmission capabilities. 
     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  FIGS. 12 and 13 , the blade  110  is generally L-shaped, having a main leg  112  and a short leg  116 . In the illustrated embodiment, the main leg  112  of the blade  110  is pitched radially forward of the drive shaft axis  114 , at a small forward angle beyond perpendicular to the drive shaft. The main leg  112  may possess a generally straight configuration (as  FIG. 12  shows), or, alternatively, it may present a generally curved surface (as  FIG. 13  shows). In the illustrated embodiment, the short leg  116  of the blade  110  is also pitched at a small forward angle from the main leg  112 , somewhat greater than perpendicular. 
     In  FIG. 14 , the blade  110  takes the shape of a continuous ring  126 . As illustrated, the ring  126  is pitched slightly forward, e.g., at an angle slightly greater than perpendicular relative to the drive shaft axis  114 . 
     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  FIGS. 12 and 13 , and the ring  126  shown in  FIG. 14 , can, in cross section, be round, rectilinear, or another configuration. 
     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  FIG. 15  shows, the drive shaft  108  of the tool  108  is deployed subcutaneously into the targeted tissue area through a guide sheath or cannula  124 . Connected to the drive motor  120 , the drive shaft  108  rotates within the guide sheath  34 , thereby rotating the blade  110  to cut a cylindrical path P in the surrounding tissue mass TM. The blade  110  can be advanced and retracted, while rotating, in a reciprocal path (arrows F and A), by applying pushing and pulling forces upon the drive shaft  108 . The blade  110  can also be withdrawn into the cannula  124  to allow changing of the orientation of the cannula  124 . In this way, successive cylindrical paths can be cut through the tissue mass, through rotating and reciprocating the blade  110 , to thereby create a desired cavity shape. 
     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  FIG. 16  shows, any of the tools  10 ,  38 ,  106 , or  138  can include an interior lumen  128 . The lumen  128  is coupled via a Y-valve  132  to a external source  130  of fluid and an external vacuum source  134 . 
     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  FIG. 20 ) on its proximal end  72  to facilitate gripping and maneuvering the tube  68 . 
     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  FIGS. 17 and 21 ). The blade  78  can be formed from stainless steel or cast or molded plastic. 
     A stylet  80  is carried by an interior track  82  within the catheter tube  68  (see  FIGS. 18 and 19 ). The track  82  extends along the axis of the catheter tube  68 . The stylet  80  is free to move in a linear aft path (arrow A in  FIG. 20 ) and a linear forward path (arrow F in  FIG. 21 ) within the track  82 . The stylet  80  is also free to rotate within the track  82  (arrow R in  FIG. 17 ). 
     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  FIGS. 19 and 20 , and an operating position, shown in  FIGS. 17 ,  18 , and  21 . When in the at rest position, the physician can push or pull upon the control knob  84  to move the blade  78  in a linear path within the catheter tube (see  FIG. 20 ). By pushing on the control knob  84 , the physician can move the blade  78  outside the catheter tube  68 , where it can be rotated into the operating condition (see  FIG. 21 ). When in the operating position, pushing and pulling on the control knob  84  moves the blade in linear strokes against surrounding tissue mass. 
     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  FIG. 4 . The physician is able to freely slide the catheter tube  68  axially within the guide sheath  34  to deploy the tool  66  in the targeted treatment site. When deployed at the site, the physician can deploy the blade  78  in the operating condition outside the catheter tube  68  and slide the blade  78  along tissue in a linear path. Linear movement of the blade  78  along tissue cuts the tissue. The physician is also able to rotate both the catheter tube  68  within the guide sheath  34  and the blade  78  within the catheter tube  68  to adjust the orientation and travel path of the blade  78 . 
     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 
       FIG. 22  shows an alternative embodiment of a linear movement tool  90  capable of forming a cavity in a targeted treatment area. The tool  90  is physically constructed in the same way as the linear movement tool  66  just described, so common reference numerals are assigned. 
     However, for the tool  90  shown  FIG. 22 , the far end of the stylet  80  carries, not a cutting blade  78 , but instead a transmitter  92  capable of transmitting energy that cuts tissue (shown by lines  100  in  FIG. 22 ). A connector  94  couples the transmitter  92  to a source  96  of the energy, through a suitable energy controller  98 . 
     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  FIG. 22 ) between a retracted position, housed with the catheter tube  68  (like the blade  78  shown in  FIG. 20 ), and a range of extended positions outside the catheter tube  68 , as shown in  FIG. 22 ). 
     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  ( FIG. 22 ) will now be described in the context of deployment in a human vertebra  150 . 
       FIG. 23  shows the vertebra  150  in coronal (top) view, and  FIG. 24  shows the vertebra  150  in lateral (side) view. It should be appreciated, however, the tool is not limited in its application to vertebrae. The tools  10 ,  38 ,  138 ,  106 ,  66 , and  90  can be deployed equally as well in long bones and other bone types. 
     As  FIGS. 23 and 24  show, the vertebra  150  includes a vertebral body  152 , which extends on the anterior (i.e., front or chest) side of the vertebra  150 . The vertebral body  152  includes an exterior formed from compact cortical bone  158 . The cortical bone  158  encloses an interior volume of reticulated cancellous, or spongy, bone  160  (also called medullary bone or trabecular bone). 
     The vertebral body  152  is in the shape of an oval disk. As  FIGS. 23 and 24  show, access to the interior volume of the vertebral body  152  can be achieved. e.g., by drilling an access portal  162  through a side of the vertebral body  152 , which is called a postero-lateral approach. The portal  162  for the postero-lateral approach enters at a posterior side of the body  152  and extends at angle forwardly toward the anterior of the body  152 . The portal  162  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 pedicle  164  (identified in  FIG. 23 ). This is called a transpedicular approach. It is the physician who ultimately decides which access site is indicated. 
     As  FIGS. 23 and 24  show, the guide sheath  34  (earlier shown in  FIG. 4 ) is located in the access portal  162 . Under radiologic or CT monitoring, a selected one of the tools  10 ,  38 ,  66 , or  90  can be introduced through the guide sheath  34 . 
     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  FIG. 4 ), or otherwise retracted within the catheter tube  12  (as  FIG. 2  shows) during passage through the guide sheath  34 . 
     Referring to  FIG. 25 , when the loop tool  10  is deployed outside the guide sheath  34  in the cancellous bone  160 , the physician operates the controller  30  in the manner previously described to obtain a desired dimension for the loop structure  20 , which can be gauged by radiologic monitoring using the on-board markers  36 . The physician manually rotates the loop structure  20  through surrounding cancellous bone  160  (as indicated by arrows R in  FIG. 25 ). The rotating loop structure  20  cuts cancellous bone  160  and thereby forms a cavity C. A suction tube  102 , also deployed through the guide sheath  34 , removes cancellous bone cut by the loop structure  20 . Alternatively, the catheter tube  12  can include an interior lumen  128  (as shown in  FIG. 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 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  FIG. 6 . 
     Referring to  FIG. 26 , when the brush tool  38  is deployed in cancellous bone  160  free of the guide sheath  34 , the physician advances the bristles  46  a desired distance (as shown in  FIG. 5 ), aided by radiologic monitoring of the markers  62 , or the indicia  32  previously described, or both. The physician connects the drive shaft  40  to the motor  56  to rotate the bristles  46 , creating the brush structure  44 . As  FIG. 26  shows, the rotating brush structure  44  cuts cancellous bone  160  and forms a cavity C. The suction tube  102  (or a lumen  128  in the drive shaft  40 , as shown in  FIG. 16 ) introduces a rinsing fluid (with an anticoagulant, if desired) and removes cancellous bone cut by the brush structure  44 . By periodically stopping rotation of the brush structure  44  and operating the controller  60  (previously described) to increase the forward extension of the bristles  46 , 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 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  FIG. 20 , until the distal end  76  of the catheter tube  68  is free of the guide sheath  34 . 
     Referring to  FIG. 27 , using the blade tool  66 , the physician operates the stylet  80  forward (arrow F) and aft (arrow A) to move the blade  78  in a linear path through cancellous bone  160 . The blade  78  scrapes loose and cuts cancellous bone  160  along its path, which the suction tube  102  removes. A cavity C is thereby formed. Synchronous rotation (arrow R) and linear movement (arrows F and A) of the blade  78  allow the physician to create a cavity C having a desired dimension. 
     Referring to  FIG. 28 , using the energy transmitting tool  90 , the physician rotates (arrow R) and pushes or pulls upon the stylet  80  (arrows F and A) to position the energy transmitter  92  at desired locations in cancellous bone  160 . The markers  86  aid the location process. Transmission by the transmitter  92  of the selected energy cuts cancellous bone  160  for removal by the suction tube  102 . A cavity C is thereby formed. Through purposeful maneuvering of the transmitter  92 , 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 selected tool  10 ,  38 ,  66 ,  90 ,  106 , or  138  is withdrawn through the guide sheath  34 . As  FIG. 29  shows, an other tool  104  can now be deployed through the guide sheath  34  into the formed cavity C. The second tool  104  can, for example, perform a diagnostic procedure. Alternatively, the second tool  104  can perform a therapeutic procedure, e.g., by dispensing a material  106  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 of such materials  106  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. patent 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 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  FIGS. 30 and 31 ) prior to deployment in bone. 
     As  FIGS. 30 and 31  show, the kit  500  includes an interior tray  508 . The tray  508  holds the particular cavity forming tool (generically designated  502 ) in a lay-flat, straightened condition during sterilization and storage prior to its first use. The tray  508  can be formed from die cut cardboard or thermoformed plastic material. The tray  508  includes one or more spaced apart tabs  510 , which hold the tool  502  in the desired lay-flat, straightened condition. 
     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  FIG. 31 ), to provide quick access to the tray  508  upon instance of use, which preferably occurs in a sterile environment, such as within an operating room. 
     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  FIG. 31 ), to provide access to the inner wrap  512 , which can be removed from the outer wrap  516  in anticipation of imminent use of the tool  502 , without compromising sterility of the tool  502  itself. 
     Both inner and outer wraps  512  and  516  (see  FIG. 31 ) each includes a peripherally sealed top sheet  520  and bottom sheet  522 . In the illustrated embodiment, the top sheet  520  is made of transparent plastic film, like polyethylene or MYLAR™ material, to allow visual identification of the contents of the kit  500 . The bottom sheet  522  is made from a material that is permeable to EtO sterilization gas, e.g., TYVEC™ plastic material (available from DuPont). 
     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.