Patent Publication Number: US-7713273-B2

Title: Device, system and method for delivering a curable material into bone

Description:
BACKGROUND 
     The present invention relates to devices and methods for stabilizing bone structures. More particularly, it relates to devices, systems and methods for delivering a curable, stabilizing material into a bone structure. 
     Surgical intervention at damaged or compromised bone sites has proven highly beneficial for patients, for example patients with back pain associated with vertebral damage. 
     Bones of the human skeletal system include mineralized tissue that can generally be categorized into two morphological groups: “cortical” bone and “cancellous” bone. Outer walls of all bones are composed of cortical bone, which has a dense, compact bone structure characterized by a microscopic porosity. Cancellous or “trabecular” bone forms the interior structure of bones. Cancellous bone is composed of a lattice of interconnected slender rods and plates known by the term “trabeculae.” 
     During certain bone procedures, cancellous bone is supplemented by an injection of a palliative (or curative) material employed to stabilize the trabeculae. For example, superior and inferior vertebrae in the spine can be beneficially stabilized by the injection of an appropriate, curable material (e.g., PMMA or other bone cement). In other procedures, percutaneous injection of stabilization material into vertebral compression fractures by, for example, transpedicular or parapedicular approaches, has proven beneficial in relieving pain and stabilizing damaged bone sites. Other skeletal bones (e.g., the femur) can be treated in a similar fashion. In any regard, bone in general, and cancellous bone in particular, can be strengthened and stabilized by a palliative injection of bone-compatible material. 
     The conventional technique for delivering the bone stabilizing material entails employment of a straight access device or cannula that bores (or otherwise cuts) through the cortical bone to gain access to the cancellous bone site. Bone stabilization material is then driven through the cannula to fill a portion of the cancellous bone at the bone site. To minimize invasiveness of the procedure, the cannula is typically a small diameter needle. 
     With the above in mind, because the needle cannula interacts with the cancellous bone and other soft tissue structures, an inherent risk exists that following initial insertion, the needle cannula might core or puncture other tissue and/or the bone mass being repaired (at a location apart from the insertion site). Thus, during percutaneous vertebroplasty, great care must be taken to avoid puncturing, coring, or otherwise rupturing the vertebral body. Similar post-insertion coring concerns arise in other interior bone repair procedures. Along these same lines, to minimize trauma and time required to complete the procedure, it is desirable that only a single bone site insertion be performed. Unfortunately, for many procedures, the surgical site in question cannot be fully accessed using a conventional, straight needle cannula. For example, with vertebroplasty, the confined nature of the inner vertebral body oftentimes requires two or more insertions with the straight needle cannula at different vertebral approach locations (“bipedicular” technique). It would be desirable to provide a system for delivering bone stabilizing material that can more readily adopt to the anatomical requirements of a particular delivery site, for example a system capable of promoting unipedicular vertebroplasty. 
     Instruments sold by Cook Medical under the OSTEO-RX™ product line utilize a curved needle to deliver bone stabilizing material as part of vertebroplasty or similar procedure. The curved needle purportedly enhances a surgeon&#39;s ability to locate and inject the stabilizing material at a desired site. Similar to a conventional straight needle cannula, the curved needle dispenses the curable material through a single, axial opening at the distal-most tip. However, the curved needle is used in combination with an outer cannula that assists in generally establishing access to the bone site as well as facilitating percutaneous delivery of the needle to the delivery site (within bone) in a desired fashion. More particularly, the outer cannula first gains access to the bone site, followed by distal sliding of the needle through the outer cannula. Once the needle&#39;s tip extends distal a distal end of the outer cannula, the needle tip is “exposed” relative to the bone site. To avoid coring, and thus potentially damaging, tissue when inserting the needle&#39;s distal tip into the bone site, an additional wire component is required, coaxially disposed within the needle and distally extending from the distal tip. The inner wire “protects” tissue or other bodily structures from traumatically contacting the distal tip of the needle as the tip is being positioned. The coaxial wire must be removed prior to infusing the bone stabilizing material through the needle. Further, the needle can only dispense the stabilizing material through the axial opening at the distal tip of the needle, perhaps impeding a surgeon&#39;s ability to infuse all desired areas and/or requiring an additional procedural step of “backing” the needle tip away from the desired delivery site. Also, because the needle tip, and thus the axial opening, is likely at or facing the bone defect (e.g., fracture in the vertebral body) being repaired, the stabilizing material may be injected directly at the defect, giving rise to a distinct possibility that the stabilizing material will forcibly progress through and outwardly from the defect. This is clearly undesirable. The issues and concerns described above in the context of percutaneous vertebroplasty can also arise in similar surgical procedures at other bone sites. 
     The injection of palliative materials into damaged or compromised bone sites has proven highly beneficial for patients. However, the known access and infusion techniques necessitate multiple needle sticks and/or risk coring bone or tissue. Therefore, a need exists for an improved device and system for delivering stabilizing material to damaged or compromised bone sites. 
     SUMMARY 
     Benefits achieved in accordance with principles of the disclosed invention include a delivery cannula providing a non-traumatic, blunt distal end that minimizes the risks of coring tissue or puncturing bone or tissue during intraosseous procedures without requiring additional components (such as separate wire). Other benefits relate to a delivery cannula defining at least one side orifice adjacent to a blunt distal end, where the orifice(s) permit a radial infusion of a curable material at a site within bone even in the case where the distal end is in contact with bone and/or tissue. Thus, a palliative bone procedure can be accomplished with reduced operating room time and with fewer approaches of surgical instruments to the bone site. For example, unipedicular vertebroplasty is readily accomplished. Further, virtually any area within the surgical site can be accessed. Also, the distal end of the delivery cannula can be placed as close as desired to a particular anatomical feature of the surgical site (e.g., a bone fracture) without fear that subsequently delivered material will forcibly progress into or through that feature. 
     Some aspects of the present invention relate to a delivery cannula device for delivering a curable material into bone. The device includes a delivery cannula and a hub forming a fluid port. The delivery cannula defines a proximal end, a deflectable segment, a distal end, a lumen, and at least one side orifice. The proximal end is axially open to the lumen. The deflectable segment is formed opposite the proximal end and terminates at the distal end that is otherwise axially closed. Further, the distal end has a blunt tip. The lumen extends from the proximal end and is fluidly connected to the side orifice(s). To this end, the side orifice(s) is formed adjacent to, and proximally space from, the distal end. Finally, the deflectable segment forms a curved shape in longitudinal extension and has a shape memory characteristic. With this configuration, the deflectable segment can be forced to a substantially straightened shape and will revert to the curved shape upon removal of the force. The hub is fluidly coupled to the proximal end of the delivery catheter. With this construction and during use, the distal end will not damage or core tissue when inserted into a delivery site within bone due to the blunt tip. Further, the side orifice(s) afford the ability to inject a curable material regardless of whether the distal end is lodged against bodily material, and can achieve more thorough dispensement. 
     Other aspects of the present invention relate to an intraosseous, curable material delivery system for delivering a curable material, such as bone cement, to a delivery site within bone. The system includes the delivery cannula and hub as described in the previous paragraph, along with a guide cannula. The delivery cannula and the guide cannula are sized such that the delivery cannula is slidable within the guide cannula. To this end, the deflectable segment is configured to deflect to a substantially straightened shape when inserted within the cannula and revert to the curved shape when extended distal the guide cannula for delivery of the curable material. In one embodiment, the guide cannula and the delivery cannula are sized to perform a vertebroplasty procedure. 
     Yet other aspects of the present invention relate to a method of stabilizing a bone structure of a human patient. The method includes providing a delivery cannula as previously described. A distal tip of a guide cannula is located within the bone structure. The delivery cannula is inserted within the guide cannula. In this regard, the deflectable segment deflects to a substantially straightened shape within the guide cannula. The delivery cannula is distally advanced relative to the guide cannula such that the distal end and at least a portion of the deflectable segment of the delivery cannula projects distal the distal tip of the guide cannula. To this end, the portion of the deflectable segment distal the distal tip of the guide cannula naturally reverts to the curved shape. The distal end of the delivery cannula is positioned adjacent a desired delivery site within the bone structure. A curable material is injected into the lumen. The injected curable material is delivered to the delivery site via the side orifice(s). Once delivered, the curable material is allowed to cure so as to stabilize the bone structure. In one embodiment, the method further includes rotating the delivery cannula relative to the guide cannula so as to alter a spatial position of the side orifice(s), thus affording the ability to inject the curable material in different planes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and are a part of this specification. Other embodiments of the present invention, and many of the intended advantages of the present invention, will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  illustrates components of an intraosseous curable material delivery system in accordance with principles of the present invention; 
         FIG. 2A  is a cross-sectional, exploded view of a delivery cannula device component of the system of  FIG. 1 ; 
         FIG. 2B  is a front view of a delivery cannula and hub portions of the device of  FIG. 2A ; 
         FIG. 3A  is an enlarged plan view of a distal portion of the delivery cannula of  FIG. 2A ; 
         FIG. 3B  is a cross-sectional view of the delivery cannula of  FIG. 3A ; 
         FIG. 4  is a cross-sectional view of the delivery cannula device of  FIG. 2A  upon final assembly; 
         FIG. 5  is a side plan view of an alternative delivery cannula device in accordance with principles of the present invention; 
         FIG. 6A  is a simplified plan view of an intraosseous curable material delivery system employed in a palliative bone procedure in accordance with principles of the present invention; 
         FIG. 6B  is a cross-sectional view of a portion of the system of  FIG. 6A ; 
         FIG. 6C  illustrates a final stage of a procedure performed by the system of  FIG. 6A ; 
         FIG. 6D  is a transverse, sectional view of a vertebral body in combination with a portion of the system of  FIG. 6A , illustrating injection of curable material; 
         FIG. 6E  is a transverse, sectional view of a vertebral body illustrating various vertebroplasty approach positions available in accordance with principles of the present invention; 
         FIGS. 7A and 7B  are simplified anterior views of a vertebral body, illustrating use of the system in accordance with principles of the present invention; and 
         FIGS. 8A and 8B  are simplified lateral views of a vertebral body, illustrating use of the system in accordance with principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates components of an intraosseous, curable material delivery system  20  according to principles of the present invention. The system  20  includes an outer guide cannula  22  and a delivery cannula device  26  (referenced generally). Details on the various components are provided below. In general terms, however, a portion of the delivery cannula device  26  is sized to be slidably disposed within the guide cannula  22  that otherwise serves to form and/or locate a desired delivery site within bone. Once positioned, the delivery cannula device  26  is employed to inject a curable, bone stabilizing material into the delivery site. The system  20  can be used for a number of different procedures, including, for example, vertebroplasty and other bone augmentation procedures in which curable material is delivered to a site within bone, as well as to remove or aspirate material from a site within bone. 
     The system  20 , and in particular the delivery cannula device  26 , is highly useful for delivering a curable material in the form of a bone cement material. The phrase “curable material” within the context of the substance that can be delivered by the system/device of the invention described herein is intended to refer to materials (e.g., composites, polymers, and the like) that have a fluid or flowable state or phase and a hardened, solid or cured state or phase. Curable materials include, but are not limited to injectable polymethylmethacrylate (PMMA) bone cement, which has a flowable state wherein it can be delivered (e.g., injected) by a cannula to a site and subsequently cures into hardened cement. Other materials, such as calcium phosphates, bone in-growth material, antibiotics, proteins, etc., could be used in place of or to augment, PMMA (but do not affect an overriding characteristic of the resultant formulation having a flowable state and a hardened, solid or cured state). This would allow the body to reabsorb the cement or improve the clinical outcome based on the type of filler implant material. With this in mind, and in one embodiment, the system  20  further includes a source (not shown) of curable material fluidly coupled to the delivery cannula device  26 . 
     Given the above, the outer guide cannula  22  generally enables access of the delivery cannula device  26  to a bone site of interest, and thus can assume a wide variety of forms. In general terms, however, the guide cannula  22  is sized to slidably receive a portion of the delivery cannula device  26 , terminating in an open, distal tip  28 . The distal tip  28  can further be adapted to facilitate coring of bone tissue, such as when using the guide cannula  22  to form a delivery site within bone. To promote a desired interface between the guide cannula  22  and a portion of the delivery cannula device  26  otherwise slidably inserted within the guide cannula  22  during use (described below), in one embodiment, an inner diameter surface of the guide cannula  22  is highly smoothed to a matte or mirror finish (i.e., RMS range of 4-16). Regardless, and in some embodiments, the guide cannula  22  can further be attached, at a proximal end thereof, to a handle  30  for enhancing a surgeon&#39;s ability to manipulate the system  20 . Alternatively, the handle  30  can be eliminated. 
     The delivery cannula device  26  is shown in greater detail in  FIG. 2A , and generally includes a handle assembly  32  (referenced generally), a hub  34 , and a delivery cannula  36 . The hub port  34  forms a fluid port and is fluidly connected to the delivery cannula  36 , with the handle assembly  32  retaining the combination hub  34 /delivery cannula  36 . As described in greater detail below, the delivery cannula  36  is sized to be coaxially, slidably received within the guide cannula  22  ( FIG. 1 ), and is adapted to deliver a curable material injected therein via the hub  34 . 
     The handle assembly  32  includes, in one embodiment, a handle  40  and a retainer  42 . The handle  40  is adapted to receive the hub  34 , with the retainer  42  securing the hub  34  (and thus the delivery cannula  36 ) to the handle  40 . 
     The handle  40 , in one embodiment, includes a first section  44  and a second section  46 . The first section  44  is adapted for snap-fit assembly to the second section  46 , such as by complimentary annular protrusion(s)  48  and grooves  50 . Regardless, the first section  44  forms a central passage  52  extending inwardly from an exterior surface  54  thereof. 
     The second section  46  defines an internal aperture  56  that, upon final assembly of the handle  40 , is aligned with the central passage  52 . The aperture  56  can assume a variety of forms sized to receive the hub  34  in a nested manner. The nested interface between the handle  40  and the hub  34  is preferably adapted such that the hub  34  cannot rotate relative to the handle  40  upon final assembly (i.e., the hub  34 /handle  40  interface resists a torque imparted on either component such that rotational movement of the handle  40  results in an identical rotation of the hug  34 /delivery cannula  36  even when the delivery cannula  36  is inserted within a confined surgical site). Thus, in one embodiment, the aperture  56  and the hub  34  (as described below) have corresponding non-symmetrical or non-circular shapes in transverse cross-section. Relative to the longitudinal cross-sectional view of  FIG. 2A , the non-circular shape of the aperture  56  is characterized by the aperture  56  being defined by a sidewall  58  having a shoulder  60  corresponding with the shape of the hub  34  as described in greater detail below. Alternatively, the sidewall  58  can assume a variety of other configurations. Regardless, and in one embodiment, the second section  46  forms exterior threads  62 . 
     The retainer  42  is configured to secure the hub  34 /delivery cannula  36  to the handle  40 , and forms a central opening  64  defining a proximal portion  66  and a distal portion  68 . The proximal portion  66  forms the central opening  64  to have a diameter slightly greater than that of the hub  34 , along with internal threads  70  sized to threadably engage the exterior threads  62  of the handle  40 . The distal portion  68  forms the opening  64  to have a diameter approximating an outer diameter of the delivery cannula  36  so as to provide a more rigid connection between the handle assembly  32  and the hub  34 /delivery cannula  36 . Alternatively, the handle assembly  32  can assume a wide variety of other forms and in some embodiments can be eliminated entirely. 
     In one embodiment, the hub  34  is of a conventional fluid port design and defines a fluid passage  71  and an exterior thread  72  on a proximal end  74  thereof. In one embodiment, the thread  72  is a double start right hand Luer thread including a 5-millimeter lead, although other thread conformations and lead sizes are also acceptable. Regardless, as previously mentioned, in one embodiment, the hub  34  is configured to be rotatably “locked” relative to the handle assembly  32  upon final assembly. Thus, in one embodiment, a body of the hub  34  forms a generally cylindrical surface  76  a portion of which is flattened in an area  78 , as shown in  FIG. 2B . The size and shape of the flattened area  78  corresponds with the aperture sidewall  58  ( FIG. 2A ) provided with the handle  40  ( FIG. 2A ). 
     The hub  34  is formed, in one embodiment, of a sterilizable polymeric material. By way of example, the hub  34  can be formed of a polylac  717 C acrylonitrile-butadiene-styrene (ABS) copolymer, although other sterilizable polymers and/or copolymers are also acceptable. 
     Returning to  FIG. 2A , the delivery cannula  36  defines a proximal end  80  and a distal end  82 , and forms one or more side orifices  84  adjacent the distal end  80  and in fluid communication with an internal lumen  86 . In addition, the delivery cannula  36  includes a deflectable segment  88  (referenced generally) defining a pre-set curve or bend  90 . As described below, the deflectable segment  88 , and in particular the bend  90 , includes or extends from the distal end  82 , and has a shape memory attribute whereby the deflectable segment  88  can be forced from the curved shape (shown in  FIG. 2A ) to a substantially straightened shape, and will naturally revert back to the curved shape upon removal of the force. 
     The proximal end  80  is axially open to the lumen  86 . Conversely, the distal end  82  is axially closed to the lumen  86  (i.e., material cannot be axially expelled from the distal end  82  relative to an axis of the lumen  86 ). That is to say, material in the lumen  86  cannot be forced distally therefrom in an axial fashion. Further, the distal end  82  defines or includes a blunt tip  100 . For example, in one embodiment, the blunt tip  100  defines a hemispherical surface, although other blunt (i.e., curved or curvilinear) shapes or contours are also acceptable. The blunt tip surface  100  is adapted to provide a non-traumatic surface suitable for accessing, contacting and probing bone or tissue while minimizing the risk of puncture and/or coring of the tissue or damage to the bone. To enhance a desired softness, the blunt tip  100  can have a differing thickness as compared to a remainder of the delivery cannula  36  such as by sintering the distal end  82  to form the blunt tip  100  (when the delivery cannula  36  is initially provided as a continuous tube). Alternatively, the blunt tip  100  can be formed apart from a remainder of the delivery cannula  36  and subsequently attached to the delivery cannula  36  to form the distal end  82  (e.g., the delivery cannula  36  can include a first tubular body formed of a hardened material along with a second, solid body formed of a softer material attached (e.g., welded) to the tubular body to form the distal end  82 /blunt tip  100 ). 
     With reference to  FIGS. 2A and 2B , the side orifice(s)  84  is formed adjacent the distal end  82 , extending through a thickness of a sidewall of the delivery cannula  36 . In one embodiment, a single orifice  84  is provided, and is located “opposite” a direction of the bend  90 . In other words, relative to the longitudinal cross-sectional view of  FIG. 2A , a direction of the bend  90  serves to form the delivery cannula  36  to define an interior bend side  102  and an exterior bend side  104 . With these designations in mind, the side orifice  84  is formed along, and is open relative to, the exterior bend side  104 . It has surprisingly been found that by positioning the side orifice  84  “opposite” the bend  90 , users will experience enhanced control over the direction in which curable material is distributed from the delivery cannula  36 , as well as improved safety. Alternatively, a greater number of side orifices  84  can be provided that may or may not be circumferentially aligned and may or may not be located along the exterior bend side  104  of the delivery cannula  36 . In general, the side orifice  84  is offset at least a distance D 1  from the distal end  82 . In one embodiment, the distance D 1  is between 0.05 inches and 0.5 inches, and preferably the distance D 1  is between 0.1 inches and 0.25 inches. With this configuration, even when the blunt tip  100  is pressed against tissue or bone, the side orifice(s)  84  is “open” and thus available for dispensing (or aspirating) material. Further, the side orifice(s)  84  provides a radial dispensing or flow direction relative to a longitudinal axis of the delivery cannula  36 . 
     The side orifice(s)  84  can assume a wide variety of shapes and sizes (relative to an exterior surface of the delivery cannula  36 ). For example, the side orifice(s)  84  can be oval, circular, curvilinear, etc. In one embodiment, and with reference to  FIG. 3A , a chamfered region  106  can be formed about the side orifice  84  to eliminate sharp edges along an exterior of the delivery catheter  36  as well as to promote consistent flow of curable material from the side orifice  84  (via the expanding orifice size effectuated by the chamfered region  106 ). With embodiments where the side orifice  84  is non-circular, an orifice length L and width W are defined. To this end, the length L is greater than 0.050 inch, preferably greater than 0.075 inch, and even more preferably greater than 0.100 inch. While the width W of the side orifice  84  may or may not be less than the length L (e.g., on the order of 0.042 inch in one embodiment), the side orifice  84  is properly characterized as being relatively large, especially as compared to conventional bone cement delivery needles that otherwise provide only an axial orifice or opening at the distal tip. 
     In particular, and with additional reference to  FIG. 3B  (otherwise illustrating a cross-sectional view of the delivery cannula  36  taken through the side orifice  84 ), the delivery cannula  36  defines an inside diameter ID (i.e., a diameter of the lumen  86 ). The side orifice  84  is fluidly connected to the lumen  86  and extends in a radial fashion. With these conventions in mind, in one embodiment, the length L of the side orifice  84  is greater the inside diameter ID of the delivery cannula  36 . As such, at least one linear dimension of the side orifice  84  is larger than any orifice dimension that could otherwise be achieved were an orifice to be formed at the distal end  82  (i.e., an axially extending orifice). That is to say, an orifice formed at the distal end  82  of the delivery cannula  82  (as is conventionally employed in the bone cement delivery needle art) is limited in size (i.e., diameter) by the inside diameter ID of the delivery cannula  36 . In contrast, the side orifice  84  in accordance with principles of the present invention is much larger, presenting a distinct advantage when attempting to pass a low viscosity liquid (curable material such as bone cement) there through. 
     Returning to  FIG. 2A , in one embodiment, the delivery cannula  36  defines a continuous length between the proximal end  80  and the distal end  82 , with the deflectable segment  88 , and in particular the bend  90 , extending along approximately 25% of the length from the distal end  82  (where the “length” of the delivery cannula  36  is the length of extension from the hub  34  upon final assembly). In other embodiments suited for other surgical procedures, the deflectable segment  88 , and in particular the bend  90 , extends along between 10%-50% of the length of the delivery cannula  36  as measured from the distal end  82 . 
     To facilitate delivery of a curable material (e.g., bone cement) into a confined site within bone (such as with a vertebroplasty procedure), the deflectable segment  88  can be formed to define the bend  90  at a pre-determined radius of curvature R appropriate for the procedure in question. In one embodiment, the bend  90  is J-shaped (approximating at least a 90 degree bend) and defines the radius of curvature R to be less than 1.5 inches, preferably in the range of 0.25-1.5 inches. In one preferred embodiment, the bend  90  defines the radius of curvature R to be approximately 1 inch. Alternatively, and as described in greater detail below, the radius of curvature R can be greater or lesser, depending upon the particular procedure for which the delivery cannula  36  is to be employed. 
     Further, to facilitate ready deflection of the deflectable segment  88  from the curved shape to a substantially straightened state (such as when the delivery cannula  36  is inserted within the outer guide cannula  22  ( FIG. 1 )) and reversion back to the curved shape, the delivery cannula  36 , or at least the deflectable segment  88 , is formed of a shape memory metal. In one embodiment, the delivery cannula  36  comprises Nitinol™, a known shape memory alloy of nickel (Ni) and titanium (Ti). In one embodiment, the bend  90  is formed in the delivery cannula  36  by deforming a straight fluid delivery cannula under extreme heat for a prescribed period of time, which pre-sets a curved shape in the delivery cannula  36 . 
     In another embodiment, the pre-set curve or bend  90  is formed in an initially straight cannula by cold working the straight cannula and applying a mechanical stress. Cold working permanently locks a crystalline structure (for example, a partial martensitic crystalline structure) in a portion (i.e., the deflectable segment  88 ) of the cannula, while an unstressed portion remains in, for example, an austenitic structure. 
     In addition to Nitinol, other materials exhibiting this shape memory behavior can be employed, including superelastic or pseudoelastic copper alloys, such as alloys of copper, aluminum, and nickel, and alloys of copper, aluminum, and zinc, and alloys of copper and zinc. Regardless, the deflectable segment  88  is formed to be resilient and to naturally assume the desired radius of curvature R. In this manner, after the delivery cannula  36 , and in particular the deflectable segment  88 , is flexed to a substantially straightened shape (not shown), upon a subsequent relaxation, the deflectable segment  88  “remembers” the pre-set curved shape and reversibly relaxes/returns to the bend  90 , as described in detail below. 
     The above material selection in combination with delivery of curable liquid through one or more, relatively large side orifice(s) (otherwise positioned proximal of the distal end  82 ) and the blunt tip  100  has surprisingly been found to allow the delivery cannula  36  to be smaller and thinner than conventional bone cement delivery needles (i.e., having an outer diameter of approximately 0.125 inch, yet still provide sufficient structural integrity to perform all desired procedures entailing delivery of curable material to, or removal of material from, a site within bone. More particularly, and as best shown in  FIG. 3B , the delivery cannula  36  defines the inside diameter (ID) and an outside diameter (OD). In one embodiment, the inside diameter ID is in the range of 0.040-0.090 inch, preferably in the range of 0.050-0.080 inch, and more preferably in the range of 0.047-0.067 inch. The outside diameter OD is selected to permit the delivery cannula  36  to be co-axially received by the outer guide cannula  22  ( FIG. 1 ). With this in mind, and in one embodiment, the outside diameter OD is in the range of 0.030-0.10 inch, preferably not greater than 0.090 inch, more preferably in the range of 0.060-0.090 inch, and more preferably in the range of 0.072-0.082 inch. Thus, in one embodiment, the delivery cannula  36  is of a reduced outer diameter and thickness as compared to available bone cement delivery needles (e.g., the curved needle available with the OSTEO-RX™ product line has an outside diameter of 0.092 inch and a wall thickness of 0.027 inch). By way of example, but in no way limiting, an exemplary delivery catheter was constructed in accordance with principles of the present invention having an outside diameter of approximately 0.077 inch and a wall thickness of 0.015 inch, and was found to be highly suitable for performing a vertebroplasty procedure. This represents a distinct advancement not heretofore available to surgeons. 
     An additional feature of the delivery cannula  36  in accordance with one embodiment is best shown in the plan view of  FIG. 1 . More particularly, the delivery cannula  36  includes indicia  110  (reference generally) adjacent the proximal end  80 . The indicia  110  is indicative of a location of the distal end  82  relative to the distal tip  28  of the guide cannula  22  upon insertion of the delivery cannula  36  within the guide cannula  22 . For example, the indicia  110  can include first, second, and third depth markings  110   a ,  110   b ,  110   c . A longitudinal location of the first depth marking  110   a  relative to the distal end  82  (when the delivery cannula  36  is forced to a substantially straightened state) is commensurate with a length of the guide cannula  22  in combination with the handle  30  (where provided). That is to say, the first depth marking  110   a  is located at a linear distance from the distal end  82  such that upon insertion of the delivery cannula  36  within the guide cannula  22  (otherwise forcing the delivery cannula  36  to a substantially straightened state), when the distal end  82  is at or even with the distal tip  28  of the guide cannula  22 , the first depth marking  110   a  will be proximally adjacent or aligned with (and visible relative to) a proximal side of the handle  30 . Thus, a user can quickly and easily have visual confirmation that the distal end  82  is within the guide cannula  22 . The second and third depth markings  110   b ,  110   c  are proximally spaced from the first depth marking  110   a  at known increments (e.g., 0.5 cm, 1.0 cm, etc.) that represent length of distal extension of the distal end  82  relative to the distal tip  28 . For example, where the second depth marking  110   b  is longitudinally spaced (proximally) a distance of 0.5 cm from the first depth marking  110   a  and the third depth marking  110   c  is spaced 0.5 cm from the second depth marking  110   b , during use when the delivery cannula  36  is inserted within the guide cannula  22  such that the second depth marking  110   b  is aligned with the proximal side of the handle  30 , a user can visually confirm (from a location away from the surgical site and outside of the patient) that an approximately 0.5 cm length of the delivery cannula  36  is extending distal the distal tip  28  of the guide cannula  22 . Similarly, when the third marking  110   c  is aligned with the proximal side of the handle  30 , an approximately 1.0 cm length of the delivery cannula  36  is exposed distal the distal tip  28 . The indicial  110  can assume a wide variety of forms differing from that shown in  FIG. 1 , and in some embodiments can be eliminated. 
     With reference to  FIG. 4 , assembly of the delivery cannula device  26  includes first securing the hub  34  to the delivery cannula  36 . In one embodiment, the hub  34  is overmolded onto the delivery cannula  36 . To provide enhanced tensile strength at the hub  34 /delivery cannula  36  interface, in one embodiment, a support body  112  is secured to the delivery cannula  36  adjacent the proximal end  80  (referenced generally) prior to forming/overmolding the hub  34 . The support body  112  is preferably a rigid material amenable to affixment to the delivery cannula  36  material (e.g., where the delivery cannula  36  is formed of Nitinol, the support body  112  can also be formed of Nitinol as thus easily welded to the delivery cannula  36 ). The support body  112  can assume a variety of shapes and sizes, but in one embodiment, is rectangular (a thickness on the order of 0.035 inch, width on the order of 0.05 inch, and a length on the order of 0.2 inch, although other dimensions are equally acceptable) so that when applied to the otherwise circular (in transverse cross-section) delivery cannula  36 , the support body  112  provides flat surfaces onto which the hub  34  is overmolded. This flat surface area interface, in turn, overtly resists “slipping” of the hub  34  relative to the delivery cannula  36  and vice-versa in response to a tensile, compressive, and/or torsional force(s) placed on either component. For example, in instances where the distal end  82  of the delivery cannula  36  is inserted or lodged within bodily material (e.g., bone or tissue) at a surgical site and a proximal pulling force is placed on the hub  34  (for example, via the handle  40 ), the delivery cannula  36  will not detach from the hub  34  even though the distal end  82  “resists” proximal movement (due to lodgment within the bodily material). Similarly, a rotational or torsional force placed upon the hub  34  will consistently translate onto the delivery cannula  36  via the hub  34 /support piece  112  interface regardless of whether the distal end  82  “resists” rotational movement due to surgical site interactions. Alternatively, however, the support body  112  can be omitted and is not a necessary element. 
     Following attachment of the hub  34  to the delivery cannula  36 , the hub  34  is mounted within the handle assembly  32  as previously described. For example, the hub  34  is nested within the aperture  56  of the handle  40 , and the retainer  42  is coaxially disposed over the hub  34 /delivery cannula  36  and secured (e.g., threadably engaged) to the handle  40 . To this end, and in one embodiment, the hub  34  is oriented relative to delivery cannula  36  such that the flattened area  78  of the hub  34  “faces” a spatial direction of the bend  90 . The previously described configuration of the handle assembly  32  thus dictates that upon assembly of the hub  34  to the handle  40 , the bend  90  will also extend in a known spatial direction relative to the handle  40 . Alternatively, a spatial direction of the bend  90  relative to the handle  40  can be visually determined following mounting of the hub  34  thereto. Regardless, in one embodiment and as best shown in  FIG. 1 , the handle assembly  32  further includes directional indicia  114  (referenced generally) along an exterior of the handle  40  that provides a user with an indication of the bend  90  direction relative to the handle  40 . For example, in one embodiment, the directional indicia  114  includes an arrow  114   a  “pointing” at the direction of the bend  90 . With this configuration, a user can readily ascertain a spatial positioning of the bend  90  relative to the handle  40  when the bend  90  is inserted within the confines of a surgical site (and thus not otherwise visible to the user). The directional indicia  114  can be applied at various locations along the handle  40  such as on both major faces (one of which is visible in  FIG. 1 ) as well as a proximal end thereof, and can assume a variety of forms. In other embodiments, the directional indicia  114  can be eliminated. Regardless, following mounting of the hub  34  to the handle assembly  32 , the delivery cannula device  26  can be used to deliver a curable material into bone. 
     Although the delivery cannula device  26  has been described as including the delivery cannula  36  otherwise forming one side orifice  84 , a variety of other configurations are also acceptable. For example, two, circumferentially aligned side orifices can be provided. Further,  FIG. 5  illustrates portions of another embodiment delivery cannula device  120  in accordance with principles of the present invention. The delivery cannula device  120  includes a delivery cannula  122  that extends a length between a proximal end  124  and a distal end  126 , and a hub  128  coupled to the proximal end  124 . The delivery cannula  122  is similar to the delivery cannula  36  ( FIG. 2A ) described above (including a blunt tip), but forms a series of longitudinally aligned side orifices  130 , spaced along a length of the delivery cannula  122 , and fluidly connected to an internal lumen (not shown). Further, the delivery cannula  122  includes a deflectable segment  132  forming a pre-set curve  134 , similar to previous embodiments. 
     A distal-most side orifice  130   a  is offset the distance D 1  from the distal end  116 . Once again, the distance D 1  is, in one embodiment, in the range of 0.05-0.5 inch, preferably in the range of 0.1-0.25 inch. A longitudinal spacing between the remaining side orifices  130  proximal the distal-most side orifice  130   a  can vary. Preferably, however, the second side orifice  130   b  defines a smaller sized opening as compared to the distal-most side orifice  130   a , and the third side orifice  130   c  is smaller than the second side orifice  130   b . This reduction in side orifice size proximal the distal end  126  promotes consistent distribution of curable material otherwise being forced through the delivery cannula  122 . 
     While three of the side orifices  130  are shown, other configurations are also acceptable. For example, multiple side orifices (i.e., more than three side orifices) can be formed longitudinally along the length of the delivery cannula  122 , and in addition, the side orifices  130  can include more than one longitudinally aligned series of side orifices. In an exemplary embodiment, the side orifices  130  that are visible in  FIG. 5  are matched by another column of longitudinally aligned side orifices formed on an opposing side of the delivery cannula  122  (and therefore not visible in the view of  FIG. 5 ). Aspects of the present invention provide for the side orifices  130  to define circular side orifices, non-circular side orifices, or a set of circular and non-circular side orifices. 
     As a point of reference, the pre-set curve  134  is curved away from a central axis C of the delivery cannula  122  such that the curvature of the pre-set curve  134  is less than the radius of curvature R of the pre-set curve  90  ( FIG. 2A ) previously described, thus illustrating another embodiment in accordance with principles of the present invention. In addition, while the side orifices  130  are depicted as formed along the pre-set curve  134 , in another embodiment at least one of the side orifices  130  is formed proximal the pre-set curve  134 . 
     Regardless of an exact configuration, the assembled delivery cannula device (such as the delivery cannula device  26  of  FIG. 4 ) in accordance with principles of the present invention is highly useful in performing a wide variety of bone stabilizing procedures as part of an overall curable material delivery system. To this end,  FIG. 6A  illustrates an intraosseous curable material delivery system  150  according to one embodiment of the present invention, employed to perform a vertebroplasty procedure. The system  150  includes the outer guide cannula  22 , the delivery cannula device  26 , a curable material source  152  fluidly coupled to the delivery cannula device  26 , and a controller  154  coupled to at least the curable material source  152 . 
     The curable material source  152  includes, in one embodiment, a canister  160  containing a curable material as previously described, and tubing  164  extending from the canister  160  to the handle assembly  30  of the delivery cannula device  26 . In this regard, the tubing  164  terminates at a fitting  166  configured to removably attach to the hub  34 . In particular, the fitting  166  is configured to fit within the passage  52  of the handle  40  and removably couple to the hub  34 . In one embodiment, the fitting  166  threads onto a Luer thread defined by the hub  34 . In another embodiment, the fitting  166  snap-fits over the hub  34 . Alternatively, a wide variety of other attachment configurations are also available. 
     The controller  154  can assume any form known in the art and is coupled to the curable material source  152 . In an exemplary embodiment, the controller  154  controls a mass flow and a mass flow rate (i.e., a fluid delivery rate) of curable material from the canister  160  to the delivery cannula device  26 . The controller  154  can include a variety of actuators (e.g., switch(es), foot pedal(s), etc.) affording a user the ability to remotely control liquid flow into the delivery cannula  36 . Alternatively, manual control can be employed such that the controller  154  can be eliminated. 
     During a palliative bone procedure, with the delivery cannula  36  partially retracted within, or entirely removed from, the outer guide cannula  22 , the outer guide cannula  22  is located at a desired delivery site within bone. For example, in a vertebroplasty procedure the outer guide cannula  22  is introduced into a vertebra  180 , preferably at a pedicle  182 . In this regard, the vertebra  180  includes a vertebral body  184  defining a vertebral wall  186  surrounding bodily material (e.g., cancellous bone, blood, marrow, and other soft tissue)  188 . The pedicle  182  extends from the vertebral body  184  and surrounds a vertebral foramen  190 . In particular, the pedicle  182  is attached posteriorly to the vertebral body  184  and together they comprise the vertebrae  180  and form the walls of the vertebral foramen  190 . As a point of reference, the intraosseous system  150  is suitable for accessing a variety of bone sites. Thus, while a vertebra  180  is illustrated, it is to be understood that other bone sites can be accessed by the system  150  (i.e., femur, long bones, ribs, sacrum, etc.). 
     The outer guide cannula  22  forms an access path to a delivery site  192  (or forms the delivery site  192 ) through the pedicle  182  into the bodily material  188 . Thus, as illustrated, the outer guide cannula  22  has been driven through the pedicle  182  via a transpedicular approach. The transpedicular approach locates the outer guide cannula  22  between the mammillary process and the accessory process of the pedicle  182 . In this manner, the outer guide cannula  22  provides access to the delivery site  192  at the open, distal tip  28 . With other procedures, the outer guide cannula  22  can similarly perform a coring-like operation, forming an enlarged opening within bone. 
     Once the outer guide cannula  22  has formed, or is otherwise positioned within bone at, the desired delivery site  192 , the delivery cannula  36  is slidably inserted/distally advanced within the outer guide cannula  22 . As illustrated generally in  FIG. 6A , the distal end  82  of the delivery cannula  36  is poised at the distal tip  28  of the outer guide cannula  22 . Approximate alignment of the first depth marking  110   a  with the handle  30  provides a user with visual confirmation (at a point outside of the patient) of the distal end  82  positioning relative to the outer guide cannula  22  distal tip  28 . Prior to further distal movement, the delivery cannula  36  is entirely within the outer guide cannula  22  such that the deflectable segment  88  ( FIG. 2A ) of the delivery cannula  36  is constrained (i.e., flexed) to a substantially straightened shape that generally conforms to a shape of the outer guide cannula  22 . This relationship is shown more clearly in  FIG. 6B  whereby a force is effectively imparted by the guide cannula  22  onto the deflectable segment  88  due to the radius of curvature R ( FIG. 2A ) defined by the deflectable segment  88  in a “natural” state being larger than an inner diameter of the guide cannula  22 . This interaction essentially “removes” the pre-set curvature of the bend  90  ( FIG. 2A ), forcing or rendering the deflectable segment  88  to a substantially straightened state (it being understood that because an inner diameter of the guide cannula  22  is greater than the outside diameter of the delivery cannula  36 , the deflectable segment  88  will continue to have a slight curvature within in the guide cannula  22 ; thus, “substantially straightened” is in reference to the delivery cannula  36  being substantially, but not necessarily entirely, linear). Thus, prior to interaction with the delivery site  192  ( FIG. 6A ), the delivery cannula  36  is flexed in a substantially straight, non-curved orientation within the outer guide cannula  22 . 
     The delivery cannula device  26 , and in particular the delivery cannula  36 , is then distally advanced within the guide cannula  22  as shown in  FIG. 6C . In particular, the delivery cannula  36  is distally maneuvered such that at least a portion of the deflectable segment  88  extends beyond the open tip  28  of the guide cannula  22  and into the delivery site  192 . The now unrestrained portion of the deflectable segment  88  naturally deflects laterally (from the substantially straight shape described above) upon exiting the guide catheter  22 , reverting to the pre-set curvature of the bend  90  previously described due to the shape memory characteristic. The user can visually confirm a length of distal extension of the delivery catheter  36  from the guide catheter  22  via a longitudinal positioning of the indicia  110   b  or  110   c  (the indicia  110   c  being visible in  FIG. 6C ) relative to the handle  30 . Further, the directional indicia  114  indicates to a user (at a point outside of the patient) a spatial direction of the bend  90  within the delivery site  192  relative to a spatial position of the handle  40 . 
     In connection with distal advancement of the delivery cannula  36 , the blunt tip  100  of the distal end  82  is hemispherically shaped (or other non-sharpened or blunt shape) and thus atraumatic relative to contacted tissue/bone. In this manner, the blunt tip  100  can contact and/or probe the vertebral wall  186  with a minimum of risk in puncturing or coring the vertebral body  184 . Thus, the blunt tip  100  offers an advantage over the conventional, sharp-edged bone cement delivery needles, and does not require a separate wire to prevent coring as is otherwise necessary with available curved needles. 
     The side orifice  84  is offset from the distal end  82  and is, therefore, available to deliver curable material into, and remove bodily material from, the delivery site  192 . In particular, the side orifice  84  can eject curable material radially from, and aspirate bodily material into, the delivery cannula  36 , even when the distal end  82  is pressed against a surface, such as an interior wall of the vertebral body  184 . 
     With the above in mind, in one embodiment, the fluid source  152  is then operated (e.g., via the controller  154 ) to deliver a curable material (not shown) to the delivery cannula  36  via the hub  34 . Curable material entering the delivery cannula  36  is forced through the lumen  86  ( FIG. 2A ) towards the side orifice  84 . As shown in  FIG. 6D , the curable material is then dispensed/injected from the delivery cannula  36  in a radial fashion from the side orifice(s)  84  and into the delivery site  192  in a cloud-like pattern  194 . Alternatively or in addition, the delivery site  192  can be aspirated by replacing the curable material source  152  ( FIG. 6A ) with a vacuum source (not shown). 
     Importantly, by injecting the curable material radially from a side of the delivery cannula  36  rather than axially from the distal most end (as will otherwise occur with conventional delivery needles), the system  150  ( FIG. 6A ) can avoid forcing the curable material into a fracture or other defect that may in turn lead to undesirable leaking of the curable material through the fracture. By way of example,  FIG. 6D  illustrates a fracture  196  in the vertebral body wall  186 . Vertebroplasty is a common solution to such vertebral fractures, with the accepted repair technique entailing positioning the distal end  82  at or “facing” the fracture  196  to ensure that the curable material is dispensed in relatively close proximity thereto. With known delivery needles, this preferred approach results in the curable material being injected directly toward the fracture  196 . In contrast, with the delivery catheter  36  of the present invention, the distal end  82  is still “facing” the fracture  196 , yet the injected curable material cloud  194  is not forced directly toward the fracture  196 . Instead, the curable material cloud  194  indirectly reaches the fracture  196  with minimal retained propulsion force such that the curable material cloud  194  is unlikely to forcibly “leak” through the fracture  196 . However, the delivery site  192  is, as a whole, still filled with the curable material cloud  194  to effectuate the desired repair. 
     As shown in  FIG. 6D , an entirety of the delivery site  192  is accessible by the delivery cannula  36 . To this end, while the guide cannula  22  has been inserted via a right posterior-lateral approach, the system  150  can effectuate a vertebroplasty procedure from a left posterior lateral approach, or to right or left anterior lateral approaches as shown in  FIG. 6E . 
     In one embodiment, and returning to  FIG. 6C , a desired volume of the curable material is delivered entirely through the delivery cannula  36 . In other embodiments in accordance with principles of the present invention, after injecting a first volume of curable material through the delivery cannula  36 , the delivery cannula  36  is disconnected from the curable material source  152  and removed from the guide cannula  22 . The curable material source  152  is then fluidly connected to the guide cannula  22  (e.g., the fitting  166  is fluidly connected to a corresponding fluid port/hub provided with the handle  30 ) and then operated to inject a second volume of curable material to the delivery site  192  via the guide cannula  22 . 
     In more general terms, during the palliative bone procedure, a clinician operating the intraosseous system  150  extends a portion of the pre-set curve  90  into the delivery site  192  otherwise defined within bone. In one embodiment, a subsequent rotation of the delivery cannula  36  rotates a spatial position of the side orifice  84  relative to the delivery site  192 , thus accessing multiple planes of the delivery site  192  with only one “stick” of the outer guide cannula  22 . Thus, by a combination of retracting the delivery cannula  36  within the outer guide cannula  22 , distally advancing the delivery cannula  36  relative to the outer guide cannula  22 , and by rotating the delivery cannula  36 , multiple planes and multiple regions of the bone site of interest can be accessed by the delivery cannula  36  with a single approach of the outer guide cannula  22 . Thus, for example, a unipedicular vertebroplasty can be accomplished with the system  150 .  FIGS. 7A-8B  generally illustrate ( FIGS. 7A and 7B  from an anterior perspective;  FIGS. 8A and 8B  from a left lateral perspective) various planes/regions of the vertebral body  182  accessible with rotation and/or advancement of the delivery cannula  36  relative to the guide cannula  22  (again with the guide cannula  22  remaining stationary). Notably, in the drawings of  FIGS. 7A-8B , a direction of the bend defined by the delivery cannula  36  is not necessarily perpendicular to the plane of the page, such that the bend may not be fully evident in each view. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. For example, while specific reference has been made to vertebroplasty procedures, the devices, systems, and methods in accordance with principles of the present invention are equally applicable to delivering curable material within multiple other bones of a patient.