Systems and methods for off-axis tissue manipulation

A surgical system and method for manipulating tissue. A steerable assembly comprises a steerable instrument and a deformable conduit. The steerable instrument comprises a control element and a deflectable portion operatively connected to the control element. The steerable assembly is directed through an access cannula such that at least a portion of the steerable assembly protrudes from the distal end of the access cannula. The steerable instrument is actuated to move a deflectable portion of the steerable instrument and a distal portion of the deformable conduit away from the longitudinal axis of the access cannula so that the deformable conduit assumes a deformed position. The steerable instrument is retracted from the deformable conduit.

FIELD OF THE INVENTION

The present invention generally relates to systems and methods for manipulating tissue. More particularly, the systems and method involve off-axis tissue manipulation.

BACKGROUND OF THE INVENTION

Osteoporosis, trauma, tumors, stress and degenerative wear can cause defects in vertebrae for which surgical intervention is useful. One of the more common ailments is vertebral compression fractures. These and other pathologies of the vertebrae are often treated with implants that can stabilize a vertebra, restore vertebra height, or to relieve pain and restore natural movement of the spinal column. One form of treatment for a vertebra is kyphoplasty. Another form of treatment is vertebroplasty.

In a typical kyphoplasty procedure, an access cannula is first placed through the skin into a vertebra to provide access inside the vertebra for other tools. Due to the location of delicate spinal structures, the access cannula is carefully placed along traditional straight access paths such as a transpedicular approach to the vertebra. Once the access cannula is in position, an expandable structure is inserted through the access cannula and into the vertebra. The expandable structure is then expanded to compress cancellous bone within the vertebra. As a result, a cavity is created in the vertebra. Once the cavity is created, hardenable material is implanted into the cavity to stabilize the vertebra. In vertebroplasty procedures, the hardenable material is implanted into the vertebra without the use of an expandable structure, i.e., the hardenable material is implanted directly into the cancellous bone in the vertebra.

Often, however, treatment of the vertebra along a straight access path is difficult due to the location of the target treatment site. In some cases, treatment requires placement of the hardenable material at a location offset from the straight access path provided by the access cannula, e.g., more centrally located in the vertebra. In prior art methods, when faced with this situation, two access cannulae are placed along two straight access paths using two transpedicular approaches (i.e., bi-pedicular) and the kyphoplasty or vertebroplasty is carried out through both access cannulae. For instance, if performing kyphoplasty, two expandable structures are separately deployed into the vertebra through the access cannulae and two cavities are created and filled with hardenable material to provide the needed treatment.

Alternatively, some prior art tools are formed of shape memory material and have pre-formed bends or curves at their distal end, such as curved needles, to access off-axis locations in tissue. The pre-formed bends typically have fixed degrees of curvature. Depending on the surgery to be conducted, the pre fixed degrees of curvature of these tools may be unable to manipulate tissue at the target site in the manner desired, and therefore, lack versatility. In other words, because the prior art tools are pre-formed, they have a predetermined degree of curvature which does not allow their use in all types of surgical applications.

Therefore, there remains a need for systems and methods that utilize minimally invasive procedures for manipulating tissue in a position that is off-axis from traditional straight axis approaches.

SUMMARY OF THE INVENTION AND ADVANTAGES

A system for manipulating tissue is provided. The system comprises an access cannula for positioning in the tissue and a steerable assembly. The steerable assembly includes a steerable instrument and a deformable conduit. The steerable instrument is capable of being removably and at least partially, disposed, in the deformable conduit. The steerable instrument comprises a control element and a deflectable portion operatively connected to the control element. The steerable instrument is capable of assuming at least a substantially straight configuration and a curved configuration when the deflectable portion protrudes from the distal end of the access cannula. The steerable instrument is actuatable to move the deflectable portion away from the longitudinal axis of the access cannula in order to deform the deformable conduit so that the deformable conduit occupies a deformed position.

A system comprising an access cannula and a steerable instrument having a deflectable portion with a plurality of movable segments is also provided. The plurality of movable segments is collectively capable of assuming at least a substantially straight configuration and a curved configuration when the deflectable portion protrudes from a distal end of the access cannula. The steerable instrument is actuatable to move the deflectable portion away from the longitudinal axis of the access cannula in order to deform the deformable conduit so that the deformable conduit occupies a deformed position.

A surgical method for manipulating tissue is further provided. The surgical method utilizes an access cannula and a steerable assembly. The steerable assembly comprises a steerable instrument and a deformable conduit. The steerable instrument is removably, and at least partially, disposed within the deformable conduit. The steerable instrument comprises a control element and a deflectable portion operatively connected to the control element. The deflectable portion is capable of assuming at least a substantially straight configuration and a curved configuration when the deflectable portion protrudes from the distal end of the access cannula. The access cannula is positioned in the tissue to be manipulated. The steerable assembly is directed through the access cannula such that at least the portion of the steerable assembly protrudes from the distal end of the access cannula. The steerable instrument is actuated while the steerable instrument is at least partially disposed within the deformable conduit to move the deflectable portion of the steerable instrument and a distal end of the deformable conduit away from the longitudinal axis of the access cannula such that the deformable conduit occupies a deformed position. The steerable instrument is retracted from the deformable conduit after the deformable conduit occupies the deformed position.

Patient anatomy presents certain challenges for offset tissue manipulation that are not adequately addressed by existing systems and methods for off-axis procedures. Tissue density may vary greatly between patients, from soft tissues outside of bone, to soft cancellous bone in an osteoporotic fracture, to much harder bone in fractures from traumatic injury or metastatic disease. Vertebrae for example will also vary greatly in shape depending on the level being treated. Pedicles and vertebral bodies progressively decrease in size from lower lumbar to upper thoracic, and the pedicle angle (as measured from a sagittal plane) varies from approximately 45° at L5 to approximately 0° at T12. The disclosed systems and methods for off-axis procedures possess the combination of properties to allow for use in both a wide range of tissue densities and varying anatomical shapes.

These systems and methods advantageously allow a clinician to access off-axis locations offset from a straight access path without utilizing multiple access paths. However, it should be appreciated that multiple access paths could be used in some situations. Furthermore, the systems and methods may allow a clinician to adjust the angle the curvature to a plurality of different angles of curvature between a substantially straight configuration and a curved configuration such that a single tool may be suitable for a wide range of surgical conditions. This increases procedural flexibility while minimizing the challenges associated with multiple access cannula insertions.

DETAILED DESCRIPTION OF THE INVENTION

The systems and methods described herein may be used for a number of different procedures including, for example, kyphoplasty, vertebroplasty, and other bone augmentation procedures, including procedures in which an implant or other treatment is delivered to a tissue location, as well as possibly to compact, displace, remove or aspirate material from a tissue site. The systems and methods may also be used to treat tissue in other regions of the body, such as soft tissue or skin. The system may furthermore be used to deliver energy to tissue using radiofrequency ablation devices and techniques.

In one embodiment, the present systems and methods advantageously allow off-axis kyphoplasty and vertebroplasty to avoid the expense and challenges involved in bi-pedicular access of the vertebra. By allowing a clinician to access cancellous bone radially offset from the longitudinal axis of an access cannula, the clinician is able to access volumes of the vertebra which are not accessible using conventional kyphoplasty and vertebroplasty approaches.

The vertebra10includes two pedicles12, cortical bone14, and cancellous bone16, along with other bodily material (e.g., blood, marrow, and soft tissue). As a point of reference, the systems and methods of the present disclosure may be suitable or readily adapted by those of ordinary skill in the art for accessing a variety of bone sites. Thus, although the vertebra10is illustrated, it is to be understood that other bone sites may be accessed and treated by the systems and methods (e.g., pelvis, long bones, ribs, and sacrum).

Referring toFIG. 1, the system comprises an access cannula18and a steerable assembly20. The steerable assembly20comprises a steerable instrument22and a deformable conduit assembly26coupled to the steerable instrument22via a hub28. The deformable conduit assembly26includes a deformable conduit24. The steerable instrument22is capable of being removably and at least partially disposed in the deformable conduit24.

The steerable instrument22is actuatable in order to deform the deformable conduit24into a deformed configuration from a normally straight configuration. One example of the deformed configuration is shown inFIG. 1. By placing the deformable conduit24into the deformed configuration, other instruments, materials, etc. can be placed in the vertebra10through the deformable conduit24at a location that is offset from a longitudinal, straight access path created by the access cannula18.

Referring toFIGS. 2 and 3, the access cannula18is configured for being positioned and placed in the tissue at the target site along a straight, longitudinal access path using a stylet (not shown) coaxially disposed in the access cannula18. The access cannula18defines a lumen about a longitudinal axis A to provide access into the internal portion of the vertebra10. The access cannula18comprises a proximal end19configured for penetrating hard tissue and a distal end21configured for manipulation. The lumen is dimensioned to allow other instruments, such as the steerable instrument22and the deformable conduit24to pass there through. In certain embodiments, the access cannula18may range in size from 6 to 13 gauge.

A cannula handle30, shown inFIG. 8, may be attached to the proximal end19of the access cannula18for longitudinally or rotationally manipulating the access cannula18. The access cannula18preferably comprises surgical grade stainless steel, but may be made of known equivalent materials that are both biocompatible and substantially non-compliant, such as other medical alloys and plastics.

A cannula hub31may be fixedly mounted to the proximal end19of the access cannula18to prevent the access cannula18from moving relative to the cannula handle30. The cannula hub31may be molded onto the proximal end19of the access cannula18or fixed thereto in other conventional ways. Likewise, the cannula hub31may be fixed to the cannula handle30by conventional methods such as adhesive, press fit, or the like.

Referring toFIG. 3, in some embodiments, a cannula adapter32is provided adjacent to the cannula handle30. The cannula adapter32is rotationally and axially locked to the access cannula18using conventional methods (via cannula handle30). The cannula adapter32may simply act as an extension of the cannula handle30. The cannula adapter32is configured to interact with the hub28of the deformable conduit assembly26. For example, the cannula adapter32may provide for releasably axially fixed attachment to the hub28, to prevent the access cannula18from moving in a longitudinal direction relative to the hub28. The cannula adapter32may be integrally formed with, or otherwise fixed to, the access cannula18, or the cannula handle30, or may be releasably attached to the access cannula18or cannula handle30. Axially fixing the hub28relative to the access cannula18, which is fixed relative to the vertebra10, minimizes the potential for disruption of the deformable conduit24while the clinician performs other steps, such as retraction or withdrawal of the steerable instrument22, or delivering an implant or treatment through the deformable conduit24.

Referring toFIGS. 3-6, the cannula adapter32comprises a body33and lock ring34rotatable relative to the body33. Referring back toFIG. 1, the lock ring34is actuated by a clinician to lock the hub28axially in place with respect to the access cannula18, while allowing the hub28to rotate relative to the access cannula18. This allows the clinician to adjust the planar orientation of the steering instrument20while remaining axially locked in place. The lock ring34is configured to urge the cannula adapter32to engage a grooved section of the hub28. The grooved section of the hub28may comprise one or more spaced grooves35.

Referring toFIGS. 5 and 6, in one embodiment, the lock ring34comprises at least one locking ramp38. The lock ring34also may comprise one or more ring tabs40, for being engaged by a clinician to rotate the lock ring34. As the lock ring34is rotated by the clinician, the locking ramp38engages one or more cantilever arms42of the body33, moving the cantilever arms42inwards towards the center of the lock ring34. As the lock ring34is in a fully rotated position (seeFIG. 6), at least one locking surface36of the cantilever arms42engages one of the spaced grooves35in the grooved section of the hub28, to prevent axial movement of the hub28relative to the access cannula18. The cantilever arms42may comprise at least one cantilever tooth44possessing the locking surface36dimensioned to engage one or more of the spaced grooves35among the plurality of axially spaced grooves35located on the grooved section of the hub28.

The lock ring34may be configured to lock after rotation of less than 90, less than 60, less than 45, or less than 30, degrees of rotation relative to the access cannula18. In one embodiment, the lock ring34may comprise a recess that interacts with a stop member disposed on the cannula adapter32. After locking, the stop member may protrude into the recess of the lock ring34and prevent the lock ring34from rotating more than a predetermined amount in either direction. During operation, as the clinician rotates the lock ring34to axially lock the access cannula18to the hub28, the stop member eventually engages a surface forming the recess and prevents the clinician from rotating the lock ring34any further. Similarly, as the clinician reversibly rotates the lock ring34to release the hub28, the stop member eventually engages an opposing surface forming the recess and prevents the clinician from rotating the lock ring34any further. Alternative stop mechanisms are also contemplated which function to prevent over-rotation of the lock ring34relative to the cannula adapter32.

Referring again toFIG. 1, the system also comprises the steerable instrument22. The steerable instrument22has a length sufficient to extend beyond the distal end25of the deformable conduit24and the distal end21of the access cannula18. The steerable instrument22also has a diameter sufficient to be slidably disposed in a lumen of the deformable conduit24.

Referring toFIGS. 7, 7A, and 8, the steerable instrument22comprises a deflectable portion48capable of assuming at least a substantially straight configuration and a curved configuration. The steerable instrument22is actuated to assume the curved configuration when the deflectable portion48protrudes from the distal end21of the access cannula18. A distal end23of the steerable instrument22may be aligned with the distal end25of the deformable conduit24, or may protrude beyond the distal end25of the deformable conduit24. In some embodiments, the distal end23of the steerable instrument22extends beyond the distal end25of the deformable conduit24by at least 0.1, 0.5, 1, or 2, mm.

The substantially straight configuration of the deflectable portion48is substantially coaxial with the longitudinal axis A of the access cannula18when the steerable instrument22is at least partially disposed within the access cannula18. The phrase “substantially straight” refers to those configurations of the deflectable portion48where the distal end23of the steerable instrument is angled away from the longitudinal axis A of the access cannula18at an angle of curvature B of less than 15, 10, 5, 3, or 1, degrees.

Referring toFIGS. 7 and 8, the curved configuration of the steerable instrument22results in the distal end23of the deflectable portion48of the steerable instrument22being radially offset from the longitudinal axis A of the access cannula18. The distal end23of the deflectable portion48may be deflected through angles of curvature B ranging from about 10 degrees to 25, 35, 60, 90, 120, or 150, degrees, or more, relative to the longitudinal axis A of the access cannula18. InFIG. 8, the distal end23of the deflectable portion48is shown deflected by an angle of curvature B of approximately 90 degrees relative to the longitudinal axis A of the access cannula18. In other words, the steerable instrument22is actuatable and capable of assuming the substantially straight configuration, a fully actuated curved position, and any desired position in between.

In some embodiments, the deflectable portion48may be actuated into a plurality of different predetermined radially offset positions with each of the plurality of different predetermined radially offset positions having an angle of curvature B, based on the angle the distal end23of the steerable instrument22extends from the longitudinal axis A of the access cannula18. In one embodiment, the deflectable portion48may be capable of curving in a single plane of motion. Alternatively, the deflectable portion48may be capable of curving in multiple planes of motion.

When the steerable instrument22is actuated, the angle of curvature B of the distal end23of the deflectable portion48may be gradually manipulated until the desired angle of curvature B is achieved. In other words, the deflectable portion48of the single steerable instrument22is capable of assuming a variety of different angles of curvature B, based on the extent of actuation of the steerable instrument22. Furthermore, the radius of curvature can be determined by extending the deformable conduit24and/or the steerable instrument22through the distal end21of the access cannula to a greater degree with respect to one another.

Alternatively, the steerable instrument22may be pre-tensioned such that upon emergence from the distal end21of the access cannula18, the deflectable portion48immediately assumes the angle of curvature B associated with the extent of pre-tensioning.

The angle of curvature B of the deflectable portion48can be observed fluoroscopically, and/or by printed or other indicia associated with the steerable instrument22. The deformable conduit24may further include indicia visible under intraoperative imaging to assist in visualizing the deformable conduit24during placement. Such indicia may include radiopaque elements, such as metal reinforcement, filler material (e.g., barium sulfate) in the polymeric components, and/or one or more radiopaque markers (not shown). The curvature of the deflectable portion48allows the distal end23of the steerable instrument22to contact tissue which is radially offset from the longitudinal axis A of the access cannula18.

Referring again toFIG. 7, the steerable instrument22may comprise a tip50located on the distal end23of the deflectable portion48. The tip50may be sharp, rounded, or blunt. The tip50may optionally include a port52which allows the implant, such as a hardenable material, to be injected into hard tissue through the steerable instrument22. Alternatively, the tip50may be occluded such that no material can pass therethrough.

Referring toFIG. 7A, the steerable instrument22includes a control element54. The deflectable portion48is operatively connected to the control element54. In the embodiment shown, the distal end55of the control element54is connected to the deflectable portion48. The deflection of the deflectable portion48of the steerable instrument22is accomplished by exerting tension on the control element54, or by moving the control element54in a longitudinal direction along a control axis C of the steerable instrument22. In one embodiment, as the steerable instrument22is actuated, the control element54is moved along the control axis C to control the angle of curvature B of the deflectable portion48.

Referring toFIG. 8, in one embodiment, the control element54operates in a plurality of tension modes including an operating tension mode that enables the deflectable portion48to place the deformable conduit24in the deformed position and a slack tension mode to allow withdrawal of the deflectable portion48of the steerable instrument22from the deformable conduit24without substantially displacing the deformed position of the deformable conduit24once deformation is complete. The phrase “substantially displacing” is intended to refer to displacement of the distal end25of the deformable conduit24, after the deformable conduit24maintains the deformed position, of more than 0, more than 0.1, more than 0.3, more than 0.5, more than 0.75, more than 1, or more than 3, cm, in a lateral direction relative to the position of the distal end25of the deformable conduit24before retraction. In the operating tension mode, at least some tension is placed on the control element54such that the deflectable portion48is prevented from returning to a non-actuated position (e.g., straight). Although tension is mentioned, it will be understood that a plurality of actuation modes could also be referenced, such as a positively actuated mode and a non-actuated mode for embodiments where tension is not used to actuate the steerable instrument22.

If the steerable instrument22is disposed outside the lumen of the deformable conduit24and the control element54is in the slack tension mode, the steerable instrument22assumes a substantially straight configuration. The slack tension mode allows the deflectable portion48to move freely, which allows easy retraction of the steerable instrument22through the deformable conduit24. In the slack tension mode, the steerable instrument22exerts substantially zero lateral force on the deformable conduit24as the steerable instrument22is withdrawn from the deformable conduit24. This allows the steerable instrument22to be slidably removed from the deformable conduit24after the deformable conduit24is in the deformed position relative to the longitudinal axis A of the access cannula18. In other words, when the steerable instrument22is operated in a slack tension mode, the deflectable portion48of the steerable instrument22becomes limp and exerts substantially no lateral force in any direction and is adapted to readily conform to the deformed position of the deformable conduit24without causing the deformable conduit24to be substantially displaced from the deformed position. This feature allows the deformable conduit24to maintain its position in softer tissues, such as osteoporotic bone, or tissues outside of bone.

In some embodiments, the control element54may comprise one or more wires, bands, rods, or cables, which are attached to the deflectable portion48. The control elements54may be spaced axially apart along the length of the deflectable portion48to allow the distal end23of steerable instrument22to move through compound bending curves. In the embodiment shown, the control element54is a single cable or wire attached to the deflectable portion48. The distal end of the control element54may be fastened to the distal end23of the deflectable portion48by welding, crimping, soldering, brazing, or other fastening technology.

Referring again toFIG. 8, the steerable instrument22may further comprise a steering handle56, and/or a control surface58. The steering handle56may allow the clinician to rotate the steerable instrument22relative to the access cannula18or the deformable conduit24. The proximal end57of the control element54may be disposed in the steering handle56. In one possible configuration, the control surface58may be at least partially disposed within the steering handle56. The control surface58is operatively connected to the control element54. Therefore, the control surface58may be manipulated by the clinician to cause the deflectable portion48of the steerable instrument22to occupy a position radially offset from the longitudinal axis A of the access cannula18and to assume a desired angle of curvature B. In other words, actuation of the control surface58may cause the deflectable portion48of the steerable instrument22to move away from the longitudinal axis A of the access cannula18. In certain exemplary embodiments, actuating the steerable instrument22comprises manually engaging the control surface58, to control the angle of curvature B of the deflectable portion48. However, the control surface58may also be engaged using mechanized, electric, or automated devices.

The control surface58may allow for continuous and positive adjustment of the angle of curvature B of the deflectable portion48throughout the entire range of possible angles of curvature B. In other embodiments, the control surface58may be configured for stepwise adjustment of the curvature of the deflectable portion48, to the plurality of possible angles of curvature B via a ratchet assembly68. Alternatively, the control surface58may be configured to place the control element54in one or more of the plurality of tension modes described above.

The control surface58may comprise a thumbwheel, slider, button, trigger, rotatable knob, or combinations thereof, and may be actuated by rotating, pulling, sliding, squeezing, or pushing the control surface58. The control surface58may be configured to allow for one-handed operation by a clinician.

Referring toFIG. 7A, the steerable instrument22further comprises a shaft60having a distal end51and a proximal end53. The control element54resides within a lumen of the shaft60, or may be provided external to the shaft60. The proximal end53of the shaft60is may be disposed within the steering handle56. The proximal end53of the shaft60is engaged by a mounting block62fixed to the steering handle56that maintains alignment of the shaft60within the steering handle56. The proximal end53of the shaft60is fixed to the mounting block62. In certain embodiments, the control element54passes through the shaft60and the proximal end of the control element54is operatively coupled to the control surface58.

In the embodiment shown, the steering handle56further comprises a guide cylinder64having a hole disposed there through. The control element54passes through the hole in the guide cylinder64. The proximal end57of the control element54is engaged by a crimp sleeve, weld, adhesive, or other fastening method to prevent the proximal end57of the control element54from being pulled back through the hole in the guide cylinder64during operation. A flexible member, such as a spring may be positioned to operably interact with both the control surface58and the control element54to control or limit the amount of force that the control surface58is able to apply to the control element54.

The steering handle56defines a void66. The guide cylinder64is slidably disposed in the void66to guide the guide cylinder64such that the guide cylinder64may move freely in a linear direction along the control axis C, substantially aligned with the shaft60but may not move transversely relative to the shaft60of the steerable instrument22. In one specific embodiment, the control surface58is presented by a trigger59, and the trigger59has a rear surface that engages the guide cylinder64as the trigger59pivots about the pivot P, which during actuation, induces tension in the control element54. The trigger59may be biased towards the slack tension mode by virtue of a trigger spring (not shown) or other device operable to bias the trigger in the non-actuated position. In certain embodiments, the control surface58is configured to apply force to the control element in only one direction of actuation. This allows the control surface58(and the control element54) to return to a rest position while remaining in slack mode, and prevents forces from other elements, such as springs, gravity, and inadvertent movement of the control surface58, from affecting the position of the deformable conduit24.

The ratchet assembly68interacts with the trigger59to selectively retain the deflectable portion48in one of the plurality of tension modes or angles of curvature B. Alternatively, or in addition to the ratchet assembly68being operatively connected to the control element54, the ratchet assembly68may be operatively connected to the control surface58. The ratchet assembly68may be selectively disengaged by touching a release button69or other device, such that the control element54may move freely between a non-actuated and an actuated position.

The ratchet assembly68may be disposed at least partially within the steering handle56. The ratchet assembly68may comprise a pawl70disposed within the steering handle56and a ratcheting member72. The ratcheting member72may comprise a plurality of teeth that are capable of being engaged by the pawl70. The pawl70may include one or more teeth which correspond to the teeth of the ratcheting member72. The ratchet assembly68may further comprise a mount to orient the ratcheting member72or pawl70such that engagement of the ratchet assembly68places the pawl70into operative position with respect to the ratcheting member72. In such embodiments, when the control element54is being actuated, the pawl70slides up over the edges of the trigger teeth of the ratcheting member72. When the control element54is no longer being actuated, the pawl70will engage one of the plurality of teeth of the ratcheting member72and prevent the control element54from returning to the non-actuated configuration until released by pressing release button69. Other configurations of the ratchet assembly68that are sufficient to selectively retain the deflectable portion48in one of the plurality of tension modes or curvature positions are also contemplated, such as a friction-based mechanism that selective retains the control element54in one of a plurality of frictionally engaged positions.

Referring toFIGS. 9-15, in one or more embodiments, the deflectable portion48of the steerable instrument22comprises a plurality of movable segments collectively capable of assuming at least the substantially straight configuration and the curved configuration. The size, shape, and/or spacing of the movable segments may affect the radius, angle of curvature, and/or limits of deflection for the deflectable portion48of the steerable instrument22. The plurality of movable segments may comprise a plurality of interlocking and individual links74. The phrase “individual links” refers to distinct and discrete members.

The plurality of individual links74allow the steerable instrument22to possess the slack mode, which enables withdrawal and retraction of the steering instrument22without substantially displacing the deformable conduit24from the deformed position. Furthermore, in one embodiment, the plurality of individual links74are in an unstrained state when the deflectable portion48assumes the substantially straight configuration. The unstrained state refers to a condition of the deflectable portion experiencing less than 3, 2.5, 2, 1.5, 1, or 0.5% strain. As a result, the clinician is not required to apply force to the control element54to straighten the deflectable portion48to the substantially straight configuration.

The plurality of individual links74, shaft60and/or control element54are capable of being actuated with less than 3, 2.5, 2, 1.5, 1, or 0.5% strain, which allows the steerable instrument22to be actuated multiple times without inducing fatigue of the individual links74and premature failure. Furthermore, the plurality of individual links74may be actuated to a fully-actuated position without any of the plurality of individual links74, the control element54, or the shaft60undergoing permanent deformation.

Referring toFIGS. 9-13, the plurality of individual links74comprises at least one first link76and at least one second link78. The distal end of the first link76engages a proximal end of the second link76. Referring toFIG. 9, a plurality of the first links76and a plurality of the second links78may be included to form the deflectable portion48. In the embodiment shown, the first and second links76,78are identical in configuration.

In the substantially straight configuration, each link of the deflectable portion48is substantially co-axial with the adjacent link. In the embodiment shown, a distal link77is provided to form the distal end23of the deflectable portion48and the shaft60is configured to receive one of the links76,78.

Each of the plurality of links74may be hollow to allow the control element54to pass therethrough. The distal end55of the control element54may be welded or otherwise fastened on an interior surface of the distal link77, or another link adjacent thereto. The actuation of the control element54may urge the distal link77in a proximal direction, which results in the curvature of the deflectable portion48, and the articulation of the remaining links. In some embodiments, the control element54is only attached to the distal link77and is not attached to the remaining links. However, in other embodiments, the control element54may be attached to two or more of the plurality of links74. In the embodiments shown, nine links74,77are shown with each adding 10 degrees deflection from shaft axis S to provide an angle of curvature B of 90 degrees for the deflectable portion48. The angle of curvature B, as shown inFIG. 10can be measured between a central shaft axis S of shaft60and a central distal axis D of distal link77.

Referring toFIGS. 10 and 13, the distal end of each of the link76,78comprises at least one slot80and the proximal end of each link76,78comprises at least one follower82. In the embodiment shown, each of links76,78have two slots80and two followers82. The followers82are configured to be movably disposed within the slots80of an adjacent link. The followers82and the slots80are arcuate in shape in some embodiments. The slots80may comprise an open-end and a closed end. In the actuated mode, the followers82of one link may touch the closed ends of the slots80of an adjacent link (SeeFIG. 10). In the non-actuated mode, the followers82of one link may be spaced apart from the closed end of the slots80of the adjacent link (SeeFIG. 9). As the steerable instrument22is actuated, the followers82follows the curve of the slots80until the end of the followers82contact the closed end of the slots80. In the embodiment shown, the shaft60includes two slots80at its distal end61. The followers82and slots80are configured such that longitudinally they are locked to one another. In other words, the followers82and the slots80, when constrained inside the deformable conduit24, provide for the links74being unable to be become disengaged from one another.

Referring toFIG. 12, the first link76may also comprise at least one protrusion84and the second link78may comprise at least one groove86, with the protrusions84sized to be movably disposed within the grooves86. Alternatively, the second link78may comprise the at least one protrusion84and the first link76comprise the at least one groove86. Referring toFIG. 11, in the embodiment shown, the first and second links76,78include both the two protrusions84and the two grooves86alternating on opposing ends. The interaction of the protrusions84and the corresponding grooves86provides additional torsional and lateral strength to the deflectable portion48. The protrusions84of the deflectable portion48that faces in the direction of curvature may be spaced from an end surface forming the corresponding grooves86of the steerable instrument22when not actuated, and may directly contact the end surfaces forming the grooves86upon actuation. In one specific embodiment, the protrusions84and the grooves86may be configured in an interlocking shape, such as a trapezoid where the protrusions84are wider at the top of the protrusions and the grooves86is correspondingly wider at the bottom, which would add additional strength and stability to the plurality of links74.

Referring toFIGS. 9 and 10, in certain embodiments, the intersection of the first link76and the second link78defines a gap104there between. The first link76and/or the second link78may comprise an angled portion90that defines a fulcrum92of rotation between the first link76and the second link78. The angled portion90is arranged at an acute angle relative to end surface94. By configuring the fulcrum92to be substantially coaxial with the curved surfaces of the slot80and follower82, the plurality of links74maintain multiple points of contact with one another during actuation of the steerable instrument22, which allows the plurality of links74to bear a substantial axial load via end surfaces94while the steerable instrument22is axially advanced through tissue, while also allowing the deflectable portion48of the steerable instrument22to exert a substantial lateral force on the deformable conduit24when the steerable instrument22is actuated. This allows the system and method to operate in harder tissue, such as non-osteoporotic cancellous bone without experiencing permanent deformation or failure. The length and angle of the angled portion90may be controlled to adjust the position of the fulcrum92. The angled portion90may be angled at 10, 20, 30, 40, 50, 60, 70, or 80 degrees or more relative to the distal end surface94of the corresponding link.

Referring toFIGS. 14 and 15, an alternative deflectable portion48ais shown that may be capable of deforming in multiple directions with the movable segment comprising a plurality of multi-directional links94. In such an embodiment, each of the plurality of multi-directional links94typically comprises at least two actuation holes96. The control element may comprise wires or cables disposed within each of these actuation holes96, allowing the deflectable portion48ato be articulated in multiple directions. By tensioning the control element that passes through a first actuation hole96ato a greater degree than the control element that passes through a second actuation hole96b, the deflectable portion48aassumes a curved configuration in a particular direction. The multi-directional links94may further comprise the slots, followers, protrusions, and/or grooves described above. Alternatively, the multi-directional links may comprise a multi-directional fulcrum98. The multi-directional fulcrum98may be rounded, such that the adjacent links may freely rotate in any direction as the deflectable portion48ais actuated. Alternatively, the deflectable portion48may be uni-directional.

Alternatively, a plurality of movable segments may comprise a plurality of hinge joints joined by a spine (not shown). The plurality of hinge joints assists in the reversible deflection of the deflectable portion of the steerable instrument. A hinged side of the deflectable portion shortens under compression, while the spine side of the deflectable portion retains its axial length, causing the deflectable portion to assume a relatively curved or deflected configuration as the control element is activated. The plurality of movable segments may be manufactured by laser cutting, electrical discharge machining, water jet cutting, or other suitable manufacturing method using a single metal tube using a pre-defined pattern, such that the tube is pre-assembled. The steerable instrument may comprise Nitinol, stainless steel, or other suitable metal alloy.

In another embodiment, the steerable instrument22does not allow a material to pass there through, and can be configured to utilize larger and stronger components, which will result in a more robust tool that can easily displace cancellous bone. In the embodiment shown, the steerable instrument22comprises a control element54disposed in the lumen defined in part by shaft60and in part by the plurality of links74, or movable segments. In one embodiment, the cross-sectional area of the lumen may be completely filled by the presence of the control element54. Alternatively, at least 25%, 40%, 55%, 65%, 75%, 85%, or 95% of the cross-sectional area of the lumen of the steerable instrument22may be occupied by the control element54. In the embodiment shown, the control element54substantially fills the lumen of the steerable instrument22. Depending on the proportion of the lumen occupied by the control element54, the lumen may function to allow the passage of the implant therethrough. Furthermore, the strength of the steerable instrument22may depend on the proportion of the lumen occupied by the control element54.

Referring toFIGS. 16-18, the deformable conduit24defines a lumen dimensioned to allow the steerable instrument22to be slid through the deformable conduit24. Referring toFIG. 1, the deformable conduit24is configured to retain the shape of the steerable instrument22when the steerable instrument22assumes the curved configuration and hence, the distal end25of the deformable conduit24is positioned at the desired location in the tissue.

The deformable conduit24is sized for insertion within the lumen of the access cannula18and includes a proximal end27and the distal end25. The deformable conduit24is dimensioned to have a sufficient length to extend through and be operable beyond the distal end21of the access cannula18. The deformable conduit24may be employed to deliver hardenable material to the target site. Thus, the deformable conduit24has an outer diameter that is smaller than a diameter of the lumen of the access cannula18; however, the outer diameter of deformable conduit24preferably will not be so small as to allow hardenable material to readily travel around the outside of the deformable conduit24and back into the access cannula18.

In certain embodiments, an inner lumen diameter of the deformable conduit24may be preferably optimized to allow a minimal exterior delivery pressure profile while maximizing the amount of hardenable material that can be delivered, such as bone cement. In one embodiment, the percentage of the lumen diameter with respect to the outside diameter of the deformable conduit24is at least about 60%, 65%, 70%, 75%, 80%, 85%, 95% or more.

The deformable conduit24may include depth markings (not shown) along a proximal section that facilitates desired locating of the distal end25of the deformable conduit24relative to the distal end21of the access cannula18during use. The deformable conduit24or the steerable instrument22may also include indicia (not shown) that show the direction of the curvature.

Referring toFIGS. 16 and 17, the hub28partially surrounds the deformable conduit24and is slidably coupled to the proximal end27of the deformable conduit24. The hub28comprises a proximal hub connector100, and a distal hub connector102. The hub defines a central passage99. The deformable conduit24is slidably disposed within the central passage99of the hub28such that the deformable conduit24can move in an axial direction relative to the hub28. The hub28may comprise a polymeric material, such as ABS, nylon, polyether block amides, or other thermoplastic.

Referring toFIG. 17, the proximal hub connector100of the hub28is configured to connect to the steerable instrument22, an expandable member, an implant delivery system, cavity creation tool, or other device. The proximal hub connector100may utilize a detent system to ensure that the hub28is axially fixed and rotationally fixed to the steerable instrument, expandable member, implant delivery system, etc. In such an embodiment, the proximal hub connector100may include one or more latches104with detent fingers (not numbered) extending proximally from the proximal hub connector100which are configured to releasably engage a notch106, void, groove, or other connector of the steerable instrument, expandable member, or implant delivery system so that the hub28is axially and rotationally fixed to the steerable instrument, expandable member, etc. The distal end of the latch104may function as a lever107, such that pressing the distal portion of the latch104towards the hub28results in the release of the detent system (the proximal end of the latch104is urged outward, thus releasing from the notch106of the corresponding component). It is also contemplated that the latch104and notch106could be replaced with other retention systems that are capable of fixing the hub axially and rotationally to the steerable instrument.

Referring toFIG. 18, the hub28is configured to connect to the access cannula18via the distal hub connector102. The distal end29of hub28has an opening (not numbered) through which the deformable conduit24slides during operation. In some embodiments, the distal hub connector102is configured to connect to the cannula adapter32. The distal hub connector102includes the grooved section of hub28previously described. The distal hub connector102interacts with the cannula adapter32to form an axial locking mechanism. In one specific embodiment previously described, the grooved section of the distal hub connector102interacts with the lock ring34to lock the hub28and cantilever arms42of body33axially in place with respect to the access cannula18, while allowing the hub28, and the deformable conduit24, to rotate relative to the access cannula18. As described above, the grooved section of the distal hub connector102may comprise one or more spaced grooves35spaced to correspond to a specific predetermined depth of the deformable conduit24relative to access cannula18depending on which spaced groove35is engaged by the cannula adapter32.

In another embodiment (not shown), the hub28may interact with the access cannula18in a manner that is not rigidly fixed. In such an alternative, the hub28employs axial force resulting from the flexure of a component or friction to resist relative movement of the access cannula18relative to the hub28. This axial force may be provided from frictional forces arising from moving parts, or from interaction of one component with an elastomeric member, such as o-ring.

Referring again toFIG. 16, the deformable conduit assembly26may comprise an axial controller110configured to urge the deformable conduit24in the axial direction relative to the hub28, within the distal end opening of the hub28and the access cannula18, without moving the access cannula18or the hub28in the axial direction. The axial controller110comprises a conduit control surface114operatively connected to the deformable conduit24. In such an embodiment, the hub28may comprise one or more guiding slots112that allow the conduit control surface114to be disposed there through. The conduit control surface114may be engaged to urge the deformable conduit24in a proximal or a distal direction relative to the hub28. This may allow the clinician to expose the expandable structure128without disturbing the expandable member126. The function may also be useful for urging the expandable structure128back into the deformable conduit24prior to withdrawal of the expandable structure128after use.

In the embodiment shown inFIG. 18, the axial controller110includes a control body111fixed to the proximal end27of the deformable conduit24. The control body111has a diameter smaller than the passage99of the hub28such that the control body111may be slidably disposed in the hub28. The control body111may comprise a tube concentrically fixed on the outer circumference of the deformable conduit24. The control body111may be coaxially positioned within the passage99of the hub28. The axial controller110comprises one or more arms113extending from the control body111. The arms113may be dimensioned and oriented to protrude though the guiding slots112. Each of slots112has a closed end that acts as a stop for the arms113to limit the amount of distal movement of the deformable conduit24. The arms113present the conduit control surfaces114. Alternative conduit control surfaces114are also contemplated, such as threaded surfaces, a helical slot and follower, or rack and pinion device. In one example, a clinician may urge the conduit control surface114axially to urge the deformable conduit24axially, such that the axial position of the deformable conduit24changes relative to the access cannula18and relative to the hub28. In another example, indicia (visible, tactile, or audible) may be provided with the deformable conduit24or expandable structure128to allow the clinician to set a precise amount of desired exposure of the expandable structure128, thus allowing the deformable conduit24to affect the proportion of the expandable structure128that contacts tissue.

The axial controller110may also function to guide the deformable conduit24such that the deformable conduit24does not rotate relative to the hub28of the deformable conduit assembly26. In one specific embodiment, this guiding function may be accomplished by positioning the conduit control surfaces114within the one or more guiding slots112of the hub28such that the conduit control surfaces114are constrained rotationally relative to the hub28, and therefore prevent the deformable conduit24from rotating relative to the hub28. The arms113may simultaneously prevent the hub28from rotating relative to the deformable conduit24. Thus, the rotational arrangement of the hub28and the deformable conduit24may be rotationally fixed to one another.

Alternatively, or in addition to such an embodiment, the control body111may comprise an alignment feature116which ensures that the control body111does not rotate in the passage99relative to the hub28. The alignment feature116may comprise a protrusion sized to slide within a channel118disposed in the hub28. The protrusion116and the channel118may be complementarily dimensioned such that the protrusion116may slide longitudinally within the channel118as the deformable conduit24moves relative to the hub28.

As shown inFIG. 16, the control body111may comprise a proximal end defining a proximal abutting surface. The proximal abutting surface may abut a distal abutting surface of the handle56of the steerable instrument22when the steerable instrument is rotationally and axially locked to the hub28, thereby constraining axial movement of the deformable conduit24so that the deformable conduit24does not move axially relative to the steering instrument22during insertion of the steerable assembly20in the access cannula18and the vertebra10.

In other embodiments, the hub28is not employed and the deformable conduit24is deployable in the access cannula18. In these embodiments, a handle may be fixed to the deformable conduit24. The deformable conduit24may be moved relative to the access cannula18to control the placement of the distal end25of the deformable conduit24.

Referring toFIGS. 19 and 20, in certain embodiments, the deformable conduit24may be a multi-layer, internally-reinforced, tube. This allows the deformable conduit24to potentially possess a combination of attributes; including high hoop strength to resist internal pressure, high axial strength for pushability, and a low lateral stiffness to allow the deformable conduit24to maintain the deformed position in softer tissues. In the embodiment shown, the deformable conduit24comprises a reinforcement120, a liner122, and/or a sheath124. However, it is also contemplated that the multi-layer tube may include 2, 4, 5, 6, or more layers. The reinforcement120typically comprises a braid, a coil, weave, or one or more longitudinal strands of reinforcing material. The reinforcing material may possess a circular, flattened rectangular, or oval cross-section, in order to optimize strength and stiffness properties while minimizing radial thickness. The reinforcing material typically comprises metal, fabric, plastic, fiberglass or alternative materials that have minimal elasticity upon deformation. In one specific embodiment, the reinforcement120comprises a braid comprising stainless steel.

The liner122may comprise a lubricious polymer. The lubricious polymer is a material that allows components such as the steerable instrument22to easily slide adjacent to the liner122. The liner122is typically inert and biologically compatible. In exemplary embodiments, the inner liner122comprises a fluoropolymer, PEBA, nylon, or combinations thereof. The inner liner122may be coated with a lubricant or coating to enhance lubricity, abrasion resistance, or another desired property.

The sheath124may comprise a polymer that is capable of resisting abrasion while contacting hard tissue or the access cannula18and is sufficiently strong to traverse hard tissue, such as bone. For example, the sheath124may comprise a thermoplastic elastomer, such as a polyether block amides or nylon.

The reinforcement120, the liner122, and the sheath124may be distinct layers. Referring toFIG. 19, the reinforcement120, the liner122, and the sheath124, may be concentrically arranged, with each element forming a distinct layer of the deformable conduit24. Alternatively, the reinforcement120may be at least partially embedded in the liner122, the sheath124, or both the liner122and the sheath124. Alternatively still, the reinforcement120may be completely embedded in single polymeric tube, with no other layers being present.

Referring toFIG. 20, the density of the reinforcement120may vary along the longitudinal dimension of the deformable conduit24. For example, a distal portion of the deformable conduit24may include less of the reinforcement material per centimeter than a proximal portion to allow for improved flexibility of the distal portion of the deformable conduit24or improved pushability of the proximal portion of deformable conduit24. Alternatively, the amount of the reinforcement material in the deformable conduit24at the distal portion may be equal to, or less than the density of the reinforcement material at the proximal portion. It is also contemplated that the reinforcement120may not extend the entire length of the deformable conduit24; rather, the reinforcement120may be provided in less than 90, 75, 50, or 25% of the length of the deformable conduit24.

Referring toFIGS. 21-23, in certain embodiments, the system further comprises an expandable member126. The expandable member126may comprise an expandable structure128, such as a balloon, stent, flexible bands (such as metal bands) or other device capable of increasing in size in the radial direction. In certain embodiments, the expandable structure128is capable of expanding to a diameter to a size larger than the diameter of the deformable conduit24. The expandable member126is typically biocompatible and dimensioned and configured to be inserted through the deformable conduit24in the deformed position. The expandable member126may further comprise one or more components appropriate for forming a cavity or void within tissue. Alternative to the expandable member, the system may employ an alternative cavity creation tool that does not expand to create the cavity.

In some constructions, the expandable member126may include one or more inflatable members (e.g., a single balloon, multiple balloons, a single balloon with two or more discernable inflation zones) constructed to transition between a contracted state in which the inflatable member may be passed through the lumen of the deformable conduit24or the access cannula18, and an expanded state in which the inflatable member expands and displaces cancellous bone16or other tissue.

Referring toFIG. 21, in the illustrated embodiment, the expandable member126typically includes an inner catheter tube134having a distal end135. The inner catheter tube134may comprise vinyl, nylon, polyethylenes, ionomer, polyurethane, and polyethylene tetra phthalate (PET). The inner catheter tube134may further comprise one or more rigid materials to impart greater stiffness and thereby aid in its manipulation, such as stainless steel, nickel-titanium alloys (Nitinol™ material), and other metal alloys. The inner catheter tube134may include multiple holes to allow inflation fluid to pass from the proximal end of the expandable member126, through the inner catheter tube134, in order to inflate the expandable structure128.

The expandable member126may further comprise an outer catheter tube136. The outer catheter tube136may comprise multiple layers, or multiple concentric tubes. The inner layer of the outer catheter tube136may comprise a relatively stiff polymer for pressure resistance, and the outer layer of the outer catheter tube136may comprise a relatively soft polymer that allows for adhesion between the outer layer and the expandable structure128. The distal end of the outer catheter tube136may abut the proximal end of the expandable structure128. The outer catheter tube136may be partially disposed within the expandable structure128, with the outer layer of the catheter tube136bonded to the proximal end of the expandable structure128.

In some embodiments, at least a portion of the inner catheter tube134may be configured with relief features to allow the inner catheter tube134to bend freely to allow for advancement through the deformable conduit24while minimizing undesired movement of the deformable conduit24. The relief features may comprise grooves, thinned areas, or a helical spiral cut through the inner catheter tube134. In the embodiment shown, the inner catheter tube134comprises a helical spiral cut. The helical spiral cut may improve the pushability of the expandable member126by acting as a spring compressed to solid height.

For embodiments where the inner catheter tube134is spirally cut, the pitch of the spiral cut may vary along the longitudinal dimension of the inner catheter tube134. For example, the distal portion of the inner catheter tube134may have a greater concentration of cuts per centimeter than the proximal portion to allow for improved flexibility of the distal portion of the inner catheter tube134relative to the proximal portion. Alternatively, the proximal portion of the inner catheter tube134may have a lesser concentration of cuts per centimeter to allow for improved stiffness and pushability of the proximal portion of the expandable member126. The spiral cut may be pitched at a ratio ranging from 0.1 to 10 rotations per centimeter of the inner catheter tube134depending on the desired stiffness of the inner catheter tube134. Alternatively, the spiral cut may be pitched at a ratio ranging from 0.5 to 8, or 1 to 3, rotations per centimeter of the inner catheter tube134. It is also contemplated that the outer catheter tube136may comprise one or more relief structures in a manner similar to the inner catheter tube134described above.

In certain embodiments, the expandable member126may comprise a stylet138. The stylet138can be flexible or rigid, and may comprise a plastic, or metal material. The stylet138may be dimensioned and configured to slide in a lumen of the inner catheter tube134, or in the gap between outer catheter tube136and inner catheter tube134.

The stylet138may include a threaded coupling to secure the stylet138to the expandable structure128to prevent movement of the stylet138during deployment of the expandable structure128. The presence of the stylet138provides axial strength as the expandable structure128is urged through the access cannula18or the deformable conduit24. Once the expandable structure128is free of the deformable conduit24(or the access cannula18) and is disposed within tissue, the stylet138can be withdrawn. The lumen of the inner catheter tube134(or the gap between outer catheter tube136and inner catheter tube134) can serve as a pathway for inflating the expandable member126, introducing rinsing liquid, to aspirate debris from the tissue, or to introduce hardenable material, such as bone cement. The inner catheter tube134may contain at least one opening in fluid communication with the inner volume of the expandable structure128. Alternatively, the inner catheter tube134or the gap between inner catheter tube134and outer catheter tube136may contain at least one opening in fluid communication with the tissue being treated.

In one specific embodiment, the inner catheter tube134may be disjoined from the outer catheter tube136and slidably disposed on the stylet138, such that during expansion of the expandable structure128, the inner catheter tube134is urged distally from outer catheter tube136. The inner catheter tube134may be configured to exert no axial force on expandable structure128. Alternatively, the inner catheter tube134may be configured to exert an axial force on the expandable structure128to affect the expanded shape.

In certain embodiments, an object or device may be inserted into inner catheter tube134to allow the clinician to apply force to expandable member128. This device may comprise the stylet138configured in a pre-formed shape to allow directional control of the expandable member126. Alternatively, a device similar to the steering instrument22, but having different dimensions, may be inserted into inner catheter tube134for further control of the expandable member126.

As an alternative to the inner catheter tube134, a solid member may be utilized (not shown). In such an embodiment, the gap between the solid member and the outer catheter tube136may allow fluid to enter and expand the expandable structure. The solid member may comprise one or more of medical alloys and polymeric materials described above. The solid member may comprise one of more of the relief features described above with respect to the inner catheter tube.

The expandable structure128may comprise a plurality of shapes, such as an hour-glass, spherical, elliptical, rectangular, pyramidal, egg-shaped, or kidney-shaped. In certain embodiments, the size and shape of the expandable structure128may be restrained with one or more additional components, such as internal and/or external restraints. In preferred embodiments the expandable structure128will be structurally robust, able to withstand (e.g., not burst) expected inflation pressures when in contact with tissue. The expandable member126may further comprise one or more additional components connected or operable through the proximal region for actuating the corresponding expandable member126, such as an inflator.

In another embodiment, the expandable member126may include a plurality of expandable structures128. The number of expandable structures128utilized in the procedure may be controlled by utilizing separate actuation passages (e.g. lumens) or members within in the expandable member126, or by using the deformable conduit24to expose only the desired number of expandable structures to the tissue. Indicia (visible, tactile, or audible) may be provided to indicate the number of expandable structures128.

Referring toFIGS. 22 and 23, the expandable member126may comprise a housing130, having one or more detent features, such as notches, such that the housing130of the expandable member126can be axially fixed relative to the access cannula18and so that the position of the expandable structure128does not move relative to the access cannula18. This connection be accomplished using the latches104similar to the connection of the steering instrument22to the hub28. This serves to prevent inadvertent axial movement of the expandable member126that may occur during retraction of the deformable conduit24or actuation of the expandable member126. In one embodiment, the housing130of the expandable member126is configured to connect to the hub28of the deformable conduit assembly26. The hub28may fixedly engage the housing130or some other portion of the expandable member126, to axially fix the position of the expandable structure128relative to the position of the access cannula18, such that the deformable conduit24may move axially relative to the access cannula18without moving the expandable member126, including not moving the expandable structure128. The housing130may have features to facilitate gripping and maneuvering of the expandable member126. Finally, the housing130may include features for attachment to another instrument, such as an inflator.

In one preferred embodiment, the expandable member126is dimensioned to extend through the deformable conduit24such that the distal end127of the expandable member126, upon insertion into the deformable conduit24, does not protrude beyond the distal end25of the deformable conduit24when the deformable conduit24is fully deployed. In this configuration, the expandable structure128stays within the lumen of the deformable conduit24until the deformable conduit24is retracted. This facilitates easier and more accurate introduction of the expandable member126into the desired location by not requiring the expandable member126to displace tissue during deployment, and may protect the expandable structure128from external damage during introductory movement into tissue.

The access cannula18, steerable instrument22, deformable conduit24, and/or the expandable member126may include one or more visual indicia (e.g., markings on the clinician-held end, radio-opaque indicia at or near the distal end), tactile indicia (e.g. change in axial force felt by the clinician), or audible indicia (e.g. clicking sounds) that enable a clinician to determine the relative positions of those components to perform the methods described below.

Referring toFIG. 24, the system may further comprise an implant140and an implant delivery system142. The implant140may comprise a biocompatible material that is configured to remain adjacent to tissue permanently, semi-permanently, or temporarily. The implant140may comprise a hardenable material, bag, sheath, stent, and/or any combination thereof.

The phrase “hardenable material” 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. Hardenable materials may include, but are not limited to, injectable bone cements (such as polymethylmethacrylate (PMMA) bone curable material), which have a flowable state wherein they may be delivered (e.g., injected) by a cannula to a site and subsequently cure into hardened, cured material. Other materials such as calcium phosphates, bone in-growth materials, antibiotics, proteins, etc., may be used in place of, or to augment the hardenable material. Mixtures of different hardenable materials may also be used.

The implant delivery system142may assume various forms appropriate for delivering the desired implant140(e.g., for delivering the hardenable material or other implant type). In certain embodiments, the implant delivery system142may comprise a chamber filled with a volume of hardenable material and any suitable injection system or pumping mechanism to transmit the hardenable material out of the chamber and through the deformable conduit24. Alternatively, the implant delivery system142may comprise a hand injection system where a clinician applies force by hand to a syringe. The force is then translated into pressure on the hardenable material which causes the hardenable material to flow out of the syringe. A motorized system may also be used to apply force. A nozzle may be connected to the implant delivery system142. The nozzle may comprise a tube configured for coaxial insertion into the deformable conduit24, thus allowing delivery of material through the deformable conduit24without contacting the inner walls of the deformable conduit24.

The implant delivery system142may connect to the deformable conduit24such that the implant140may be delivered through the lumen of the deformable conduit24to the target site. The implant delivery system142may connect to the proximal end of the hub28such that the deformable conduit24can be gradually or immediately retracted during the step of placing the implant140. This locking can be accomplished using the latches104of the hub28to engage one or more notches located on the implant delivery system, similar to the notches of the expandable member126. Another embodiment may include an adapter configured to allow attachment of a cement cannula (e.g., a rigid tube configured to be filled with hardenable material) to the deformable conduit24, thus allowing the clinician to urge material through the deformable conduit24by using an instrument to displace material from the cement cannula.

In yet another embodiment, the system may comprise an aspiration device. The aspiration device functions to extract unwanted tissue, marrow products (blood precursors and marrow fat) that get displaced during performance of the described method. The system may be configured for aspiration from a lumen or gap within or between parts (e.g. a lumen within the expandable member126or deformable conduit24, from the gap between the expandable member126and the deformable conduit24, or from the gap between the deformable conduit24and the access cannula18). The aspiration device may comprise a suction port and a seal that allows passage of instruments while preventing escape of fluids (i.e. a hemostasis valve) that attaches to or is integral to the access cannula18or the deformable conduit24. The hemostasis valve may also connect to a suction tube. The hemostasis valve may be connected to a vacuum pump or a vacuum-generating syringe, and may have a check valve a fluid/tissue collection chamber. If performing a bi-pedicular procedure, the aspiration device could be used to aspirate on the contra lateral side which could influence the implant140to come across the midline. The aspiration device may be integrated with the implant delivery system142or may be used independently of the implant delivery system142. The aspiration device may be utilized in combination with the various devices and methods disclosed herein.

This disclosure also relates to a surgical method for manipulating tissue. The method may comprise providing the access cannula18, the steerable assembly20, and the implant140. The steerable assembly20comprises the steerable instrument22and the deformable conduit24with the steerable instrument22removably disposed within the deformable conduit24.

Referring again toFIG. 1, the target site for manipulation may be identified by a clinician. Identification of the target site may include locating a pre-determined location within tissue for surgical intervention. In one embodiment, identifying the target site may comprise locating a central location in the cancellous bone16of the vertebra10that will support height-restoration and/or structural augmentation that preferably is at least generally symmetrical with respect to the vertebra10. Several distinct methods are described herein. Although they are described individually, it is to be appreciated that the steps may be interchangeable and may be substituted with one or more alternative steps.

The following methods may be accomplished under either a local anesthetic or short-duration general anesthetic. The procedure is typically performed using intraoperative imaging such as fluoroscopy or CT. Once the area of the spine is anesthetized, an incision is made and a penetrating guide pin may be used to perforate the tissue and gain access to the target site. An expander may be slid over the guide pin to further retract tissue. The clinician slides the access cannula18over the expander and guide pin until the end surface of the access cannula18penetrates the vertebra10. The clinician then removes the guide pin and expander and inserts the drill to create a channel in the cortical bone14. The clinician can now remove the drill leaving only the access cannula18. In alternative embodiments, the guide pin and/or an expander are not used, but instead, the access cannula18is placed through the tissue with an access stylet coaxially locked to the access cannula. The access stylet has a sharp distal end to core into the cortical bone of the vertebra10. The access cannula18may have a similarly sharp distal end21to penetrate the vertebra10with the access stylet. Once the access cannula18is in place in the cancellous bone16, the access stylet is removed. Once the channel through the pedicle12and into the vertebra10is created, various methods may be used to stabilize the subject vertebra10.

Referring toFIG. 1, the method may further comprise directing the steerable assembly20through the access cannula18such that at least a portion of the steerable assembly20protrudes from the distal end21of the access cannula18into tissue at the target site. More specifically, the method may include positioning the steerable instrument22in the deformable conduit24until the latches106lock into the notches106in steerable instrument22and then sliding this steerable assembly20through the access cannula18to the target site. The fluoroscope imaging is continuously observed during insertion to verify placement of the deformable conduit24into the target tissue. If the steerable instrument22includes depth markings, the appropriate depth marking of the steerable instrument22will be aligned with the corresponding line on the access cannula18as additional confirmation that the distal end of the steerable instrument22is extended to the target site in the tissue to be manipulated.

As the steerable instrument22is advanced out of the distal end21of the access cannula18, the steerable instrument22may be simultaneously actuated while the deflectable portion48of the steerable instrument22is disposed within the deformable conduit24to move the distal end23of the steerable instrument22and the distal end25of the deformable conduit24away from the longitudinal axis A of the access cannula18such that the deformable conduit24occupies the deformed position. The step of actuating the steerable instrument22comprises deflecting the deflectable portion48of the steerable instrument22to the curved configuration. As the steerable instrument22is actuated to cause the deflectable portion48to curve, the distal end25of the deformable conduit24moves in the same direction, resulting in the formation of a channel, void, or cavity in the tissue. The clinician can influence the size and shape of the channel based on the degree of actuation of the steerable instrument22and whether the steerable instrument22is rotated during actuation.

The deformed position is defined as a position of the deformable conduit24assumed after the steerable instrument22urges the distal end25of the deformable conduit24away from the distal end of the access cannula18. Accordingly, the deformable conduit24can assume a variety of deformed positions, each having a different angle of curvature and radius based on the position of the distal end25of the deformable conduit24relative to the longitudinal axis A of the access cannula18. In this manner, a clinician may determine a desirable curvature to reach the target site and actuate the steerable instrument22to a degree sufficient so that the deflectable portion48assumes the desired angle of curvature and radius, which in turn deforms the deformable conduit24to assume substantially the same angle of curvature. The clinician is able to observe the placement of the various components under intraoperative imaging due to inherent radiopacity of certain elements of the steerable assembly20

The step of actuating the steerable instrument22comprises manually engaging the control surface58. This manual engagement may comprise squeezing, rotating, or sliding the control surface58to actuate the control element54of the steerable instrument22. The clinician may obtain feedback on the degree of actuation from indices previously described (visible, tactile, audible) and by direct visualization steerable assembly20in the tissue with intraoperative imaging. Actuation of the control element54(or control surface58) may be performed at any time during the advancement of steerable assembly20, including before, during, or after the distal end of the steerable assembly20has entered the tissue. There may be certain advantages to actuating before the steerable instrument22begins exiting distal end of the access cannula18. This causes potential energy to be stored within the steerable instrument22, which results in immediate lateral deflection of the deflectable portion48of steerable instrument22as the steerable instrument22is advanced distally from the access cannula18. The clinician may employ feedback from the device (visible, tactile, or audible) to impart a desired amount of energy to the mechanism that will result in a desired amount of curvature upon advancement. If the steerable instrument22includes a locking mechanism as described before, the clinician may stop applying force to the control element54(or control surface58) and allow the locking mechanism to retain and release the stored energy during advancement of the steerable assembly20. This may allow the clinician to focus less attention on actuating the steerable instrument22and more on safely reaching the target location in the tissue.

The method may, upon reaching the target tissue, comprise locking the hub28of the deformable conduit assembly26at least axially in place with respect to the access cannula18, which allows passage or withdrawal of instruments within the deformable conduit24without moving the deformable conduit24. The locking mechanism may allow the deformable conduit24to rotate relative to the access cannula18to facilitate rotation of the steering instrument22or other instrument disposed within the deformable conduit24. In one exemplary embodiment, the step of locking the hub28of the deformable conduit assembly26axially in place with respect to the access cannula18comprises rotating the lock ring34to lock the hub28of the deformable conduit assembly26in place.

Referring toFIG. 25, the method may further comprise retracting and removing the steerable instrument22from the deformable conduit24after actuation of the steerable instrument22. This includes retracting the steerable instrument22from the deformable conduit24when the control element54is operating in the slack tension mode without causing the deformable conduit24to deviate substantially from the deformed position. The steerable instrument22is generally retracted in an axial direction from within the deformable conduit24such that the deformable conduit24is no longer occluded by the steerable instrument22and can allow other components to be disposed within the lumen of the deformable conduit24, such as the expandable structure128or the implant140.

In certain embodiments, the method may comprise releasing the tension of the steerable instrument22before retracting the steerable instrument22from the deformable conduit24such that the distal end23of the steerable instrument22is adapted to readily conform to the deformed position of the deformable conduit24without causing the deformable conduit24to be substantially displaced from the deformed position. In one embodiment, the step of releasing may comprise operating in the slack tension mode of the steerable instrument22. By releasing the tension of the steerable instrument22before retracting, the deformable conduit24is less likely to be deformed by the retraction of the steerable instrument22. Reducing the amount of deformation ensures that the distal end25of the deformable conduit24remains adjacent to the target site, which allows precise placement of the implant140and/or the expandable structure128.

Referring toFIGS. 26-28, in some embodiments the expandable member126is utilized. The method comprises inserting the expandable member126through the deformable conduit24(FIG. 26), retracting the deformable conduit24to expose the expandable structure128(FIG. 27), and expanding the expandable structure128to form a cavity in the tissue (FIG. 28). In such embodiments, the step of placing the implant140is further defined as placing the implant140at least partially within the cavity formed by the expandable structure128. Once the cavity is formed, the expandable structure128may then be returned to its contracted (e.g., deflated) state, and retracted from the deformable conduit24.

The clinician identifies the shape of the tissue to be displaced and the local structures that could be damaged if the expandable structure128were expanded in an improper fashion. The clinician is also able to identify the expanded shape of the expandable structure128inside tissue based upon prior analysis of the morphology of the target site using, for example, plain film x-ray, fluoroscopic x-ray, or MRI or CT scanning. When the expandable structure128is used in bone in combination with a hardenable material, the expanded shape inside is selected to optimize the formation of a cavity that, e.g., when filled with the hardenable material, provides support across the region of the bone being treated. The expandable structure128is typically sized such that at least 25, 50, 75, or 90, % of cancellous bone16should be compressed.

The step of expanding the expandable member126may result in contacting tissue with the expandable structure128, such as cancellous bone16. In some configurations, the step of expanding the expandable structure128to form a cavity is further defined as expanding the expandable structure128in a position radially offset from the longitudinal axis A of the access cannula18.

The method further comprises locking the expandable member126in place such that the expandable member126is restricted from moving in a longitudinal direction with respect to the access cannula18. The expandable member126may be locked in position relative to the hub28of the deformable conduit assembly26, thus statically defining the position of the expandable structure128with respect to the access cannula18. This locking may allow independent motion of the deformable conduit24relative to the expandable structure128.

Referring toFIG. 27, the method may further comprise retracting the deformable conduit24in a longitudinal direction relative to the access cannula18while the expandable member126remains in a substantially constant position with respect to the access cannula18such that at least a portion of the expandable structure128becomes at least partially uncovered by the deformable conduit24. The expandable structure128may be fully uncovered, or may be uncovered by only 25, 35, 45, 55, 65, 75, or 85 or more, %, based on the longitudinal dimension of the expandable structure128. In embodiments where the expandable structure128is not fully uncovered, the method may comprise expanding the expandable structure128while the expandable structure128remains at least partially disposed and constrained within the deformable conduit24. This may allow the clinician to more directly control the shape of the cavity created by the expandable structure. The clinician may use indicia (visible, tactile, or audible) provided with the deformable conduit24or expandable structure128to set the amount of desired exposure of the expandable member126.

Referring again toFIG. 24, the method includes placing an implant140into the tissue through the access cannula18or the deformable conduit24. The step of placing the implant140may further comprise injecting the hardenable material into the channel formed by the steerable assembly20. Alternatively, the step of placing the implant140may further comprise placing the hardenable material through the deformable conduit24. In certain embodiments, the method comprises locking the implant delivery system142in place with respect to the access cannula18and the hub28of the deformable conduit24, which allows the deformable conduit24to move axially with respect to the implant delivery system142, without substantially moving the implant delivery system142or the access cannula18. Along these lines, the method may comprise retracting the deformable conduit24in a longitudinal direction relative to the access cannula18while simultaneously urging hardenable material through the deformable conduit24. This allows the hardenable material to occupy the entire channel once occupied by the deformable conduit24in the tissue to be displaced. The retraction may be performed gradually at a variety of speeds.

It is to be understood that the appended claims are not limited to express and particular systems or methods described in the detailed description, which may vary between particular embodiments that fall within the scope of the appended claims.

It is also to be understood that any ranges and subranges relied upon in describing various embodiments of the present invention independently and collectively fall within the scope of the appended claims and are understood to describe and contemplate all ranges, including whole and/or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present invention and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range “of from 0.1 to 0.9” may be further delineated into a lower third, i.e., from 0.1 to 0.3, a middle third, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims and may be relied upon individually and/or collectively and provide adequate support for specific embodiments within the scope of the appended claims.

In addition, with respect to the language which defines or modifies a range, such as “at least,” “greater than,” “less than,” “no more than,” and the like, it is to be understood that such language includes subranges and/or an upper or lower limit. As another example, a range of “at least 10” inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange from 25 to 35, and so on, and each subrange may be relied upon individually and/or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range “of from 1 to 9” includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims.