Patent Description:
One treatment modality includes vertebral augmentation in which the height of the vertebral body is elevated or restored, and stabilized at the elevated or restored height. A vertebroplasty includes delivering curable material, for example a bone cement, within an interior of the vertebral body. The material interdigitates with cancellous bone and cures to stabilize the vertebral body. A kyphoplasty includes creating a cavity within the interior of the vertebral body by compressing the cancellous bone with an expandable member such as a balloon, and delivering the curable material into the cavity. The expandable member may facilitate elevating or restoring the height of the vertebral body.

Accessing the interior of the vertebral body often includes percutaneously placing an access cannula through a pedicle of the vertebra. Owing to the structure of the vertebra, accessing a location on the contralateral side of the vertebral body is not especially feasible with straight instrumentation. As such, one existing kyphoplasty technique employs a bipedicular approach in which two access cannulas are placed, followed by two expandable members each positioned ipsilaterally within the interior of the vertebral body. The bipedicular approach undesirably requires twice the trauma to tissue, and often requires twice the instrumentation.

Of particular interest is a unipedicular approach in which the instrumentation is designed to access locations of the interior of the vertebral body offset from a longitudinal axis of the access cannula, including locations on the contralateral side of the vertebral body. One exemplary system utilizing the unipedicular approach is disclosed in <CIT>, and sold under the tradename Avaflex by Stryker Corporation (Kalamazoo, Mich. While the disclosure realizes the benefits of the unipedicular approach, there is further need in the art for systems and methods for off-axis vertebral augmentation.

<CIT> discloses devices for augmenting bone, such as in performing vertebroplasty. A bone cement injection needle is provided, having a laterally deflectable distal end. The distal end may be provided with a cavity creation element, such as an inflatable balloon. Systems are also disclosed, including the steerable injection needle, introducer and stylet. The system may additionally include a cement delivery gun, one-time use disposable cement cartridges and a cement mixing chamber.

<CIT> discloses devices that displace bone or other hard tissue to create a cavity in the tissue, where such devices rely on a driving mechanism for providing moving of the device to form a profile that improves displacement of the tissue. These devices also allow for creating a path or cavity in bone for insertion of bone cement or other filler to treat a fracture or other condition in the bone.

Further developments are set forth in the dependent claims. The appended claims do not include a method claim. Aspects falling within the scope of the claims or useful for understanding the claimed invention are set forth below.

A first aspect of the present disclosure is directed to method of augmenting a vertebral body (not claimed). A distal end of an access cannula is positioned within the vertebral body such that a lumen of the access cannula provides access to an interior region of the vertebral body along a longitudinal axis. A shaft of the introducer device and the sheath are directed to within the access cannula such that the distal portion of the introducer device and the flexible region of the sheath remains within the access cannula. The introducer device is in an unconstrained state in which a pulling element is at a first tension. Thereafter, an input to an actuator to move the introducer device from the unconstrained state to a constrained state in which the pulling element is at a second tension greater than the first tension. The access cannula prevents the distal portion of the shaft and the distal portion of the sheath from assuming a curve from the longitudinal axis. Thereafter, the introducer device and the sheath device are advanced relative to the access cannula with the introducer device in the constrained state such that the distal portion of the introducer device and the distal portion of the sheath assume the curve within the vertebral body with advancement beyond the distal end of the access cannula.

In certain implementations, the distal portion of the introducer device and the flexible region of the sheath and configured to plunge through cancellous bone within the vertebral body while assuming the curve. Prior to plunging, a distal end of the sheath may be positioned in registration with the distal end of the access cannula. Indicia disposed on the sheath may be aligned with a hub of the access cannula so as to position the distal end of the distal portion in registration with the distal end of the access cannula.

In certain implementations another input may be provided to the actuator to move or return the introducer device from the constrained state to the unconstrained state. The introducer device may be removed from the sheath device. In particular, the pulling element being at the first tension in the unconstrained state provides for removal of the introducer device from the sheath with the flexible region of the sheath remaining curved within the vertebral body. The cancellous bone of the vertebral body may at least partially support the curve. Should the curve not be positioned in the desired orientation, for example, the introducer device may be redirected through the sheath device. Thereafter, still another input to the actuator to move the introducer device from the unconstrained state to the constrained state so as to reestablish the curve of the flexible region to selectively adjust the orientation of the curve. The adjustment may not require the removal of the sheath device from the access cannula. Thereafter, the introducer device may be returned to the unconstrained state, and removed from the sheath device.

In certain implementations, the system includes a spacer lock defining an aperture and including legs defining at least one slot. The legs of the spacer lock may be engaged with a cannula hub of the access cannula such that the aperture is aligned with the lumen. A sheath hub of the sheath is disposed within the slot(s). A treatment device may be directed through the aperture to within the sheath. The treatment device is flexible to bend along the curve of the flexible region of the sheath disposed within the vertebral body. The sheath hub may be proximally moved within the slot(s) of the spacer lock with corresponding movement of the sheath, thereby exposing the treatment device at a target location within the vertebral body. Augmentation of tissue of the vertebral body may be performed at the target location with the treatment device. The treatment device may be one of a cavity-forming device configured to displace tissue, an electrode probe configured to ablate tissue, a drill device for cutting tissue, and a tissue capturing device for tissue biopsy, among others. An input may be provided to the lock actuator of the spacer lock to disengage the lock actuator from a shaft of the treatment device. The treatment device may be moved within the aperture of the spacer lock to selectively adjust a position of the treatment device relative to the access cannula. The input may then be removed to reengage the lock mechanism and the shaft of the treatment device, thereby preventing further movement of the treatment device relative to the access cannula.

In certain implementations, the treatment device may be removed from the sheath. A curved path remains in the vertebral body that is along the curve previously assumed by the introducer device. The flexible region of the sheath is advanced relative to the distal end of the access cannula. A preformed bend of a polymeric sleeve associated with the flexible region of the sheath facilitates the sheath following the curved path. Curable material may be delivered through the sheath to within the vertebral body. The polymeric sleeve may also prevent egress of the curable material through articulating features of the metal tube.

A second aspect of the present disclosure is directed to system of augmenting a vertebral body. An access cannula includes a cannula hub, and a cannula shaft extending from the cannula hub. The cannula shaft includes a distal end positionable within the vertebral body and defining a lumen along a longitudinal axis. An introducer device includes an actuator, a shaft, and a pulling element. The actuator configured to receive an input from a user. The shaft includes a proximal portion that is rigid, and a distal portion that is articulable. The pulling element is coupled to the actuator and configured to be tensioned to move the introducer device from an unconstrained state in which the distal portion is oriented along the longitudinal axis, and a constrained state in which the distal portion is configured to assume a curve away from the longitudinal axis. The shaft is removably disposed within a sheath. The sheath includes a metal tube having articulating features to define a flexible region configured to extend along the distal portion of the shaft, and a polymeric sleeve coupled to the metal tube and extending between opposing ends of the flexible region. The polymeric sleeve is configured to prevent egress of curable material being delivered through the sheath through the articulating features.

In certain implementations, the polymeric sleeve is disposed within the metal tube. Alternatively, metal tube may be disposed within the polymeric sleeve. In particular, the polymeric sleeve may extend over the proximal portion to a sheath hub of the sheath. The polymeric sleeve may include a preformed bend. A helical cut pattern may be disposed within the flexible region of the metal tube.

In a third aspect of the disclosure is directed to a method of augmenting a vertebral body (not claimed) with the system according to the second aspect of the disclosure, and optionally, any of its corresponding implementations. The system of the second aspect of the disclosure, and optionally, any of its corresponding implementations, may be used to perform the method according to the first aspect of the disclosure.

A fourth aspect of the disclosure is directed to a system for augmenting a vertebral body. An access cannula includes a cannula hub, and a cannula shaft extending from the cannula hub. The cannula shaft includes a distal end positionable within the vertebral body and defining a lumen along a longitudinal axis. An introducer device includes a shaft includes a distal portion configured to assume a curve when deployed beyond the distal end of the cannula shaft. A sheath device includes a sheath hub, and a sheath extending from the sheath hub. The shaft is removably disposed within the sheath. A spacer lock is configured to facilitate proximal movement of the sheath relative to the access cannula. The spacer lock includes legs configured to be removably positioned in abutment with an engagement surface of the access cannula, and defining at least one slot sized and shaped to slidably receive the sheath hub and prevent rotation of the sheath relative to the spacer lock.

In certain implementations, the spacer lock is configured to rest upon the engagement surface under influence of gravity without an additional coupling mechanism. The cannula hub may include handles spaced proximal to the engagement surface. The legs and the handles are positioned in an interlocking arrangement such that opposing aspects of at least one of the handles may prevent rotation of the spacer lock relative to the access cannula. The sheath hub being disposed within the slots prevents rotation of the sheath relative to the spacer lock, and optionally relative to the access cannula.

In certain implementations, the spacer lock further includes a lock actuator configured to receive an input from a user, and a lock mechanism configured to releasably engage the shaft of a treatment device in response to the lock actuator receiving the input so as to selectively permit movement of the treatment device relative to the sheath device. The lock mechanism may include a torsion spring configured to bias the lock actuator a closed state in which the lock mechanism engages the shaft of the treatment device. The lock mechanism may include a disc having thinned regions defining slots and an opening. The thinned regions are configured to resiliently deflect under force from the input to the lock actuator. The lock mechanism is configured to be in a natural or closed state in which a size of the opening is slightly smaller than an outer diameter of the shaft of the treatment device.

In some implementations, the spacer lock of the fourth aspect may be included with the system according to the second aspect of the disclosure, and optionally, any of its corresponding implementations.

A fifth aspect of the disclosure is directed to a system for augmenting a vertebral body. An access cannula includes a cannula hub, and a cannula shaft extending from the cannula hub. The cannula shaft includes a distal end positionable within the vertebral body and defining a lumen along a longitudinal axis. An introducer device includes a shaft includes a distal portion configured to assume a curve when deployed beyond the distal end of the cannula shaft. A sheath device includes a sheath hub, and a sheath extending from the sheath hub. The shaft is removably disposed within the sheath. A spacer lock configured to facilitate proximal movement of the sheath relative to the access cannula. The spacer lock includes a lock mechanism defining an aperture sized to slidably receive the tube, and a lock actuator coupled to the lock mechanism. The lock actuator is configured to receive an input from a user to selectively permit movement of a cavity-forming device relative to the access cannula or the sheath device.

In certain implementations, the lock mechanism biased to a closed state. The spacer lock may include legs, and flanges may extend radially outwardly from the legs to provide a proximal surface for accommodating a thumb of a hand of a user. The cannula hub may include handles with the legs and the handles positioned in an interlocking arrangement to prevent rotation of the spacer lock relative to the access cannula.

In some implementations, the spacer lock of the fifth aspect of the disclosure may be included with the system according to the second aspect, and optionally, any of its corresponding implementations.

A sixth aspect of the disclosure is directed to a method of augmenting a vertebral body (not claimed). A distal end of an access cannula is directed within the vertebral body to provide access to an interior region of the vertebral body along a longitudinal axis. A shaft of the introducer device and a sheath are directed to within the access cannula. The introducer device is operated to cause a distal portion of the shaft and a flexible region of the sheath to assume a curve within the interior region of the vertebral body. The shaft is removed from the sheath. The flexible region of the sheath remains along the curve. Thereafter, the sheath hub is aligned with at least one slot of the spacer lock. Legs of the spacer lock are positioned on an engagement surface of the access cannula such that the spacer lock is disposed within the slot(s). Rotation of the sheath relative to the spacer lock is prevented. The sheath hub is moved proximally within the slot(s) to move the sheath relative to the access cannula, and optionally relative to a treatment device.

In certain implementations, an expandable member and a tube of a cavity-forming device are directed through an aperture in the spacer lock such that the expandable member is in registration with a distal end of the sheath and the hub contacts the spacer lock. The sheath hub may be moved within the slot(s) towards the hub so as to expose the expandable member beyond the distal end of the sheath. An input may be provided to a lock actuator of the spacer lock to disengage the lock actuator from the tube of the cavity-forming device. The tube may be moved within the aperture of the spacer lock to selectively adjust a position of the expandable member relative to the access cannula or the sheath. The spacer lock and the cavity-forming device may be decoupled from the access cannula, thereby exposing a Luer fitting on the sheath hub.

In certain implementations, an electrode shaft is directed through an aperture in the spacer lock such that a probe of an electrode probe is in registration with a distal end of the sheath and the electrode hub contacts the spacer lock. The sheath hub may be moved within the slot(s) towards the electrode hub so as to expose the probe beyond the distal end of the sheath.

In some implementations, the spacer lock of the sixth aspect may be included with the system according to the second aspect, and optionally, any of its corresponding implementations.

A seventh aspect of the disclosure is directed to an introducer device for augmenting a vertebral body. A handle defining a proximal opening and includes a ramp, and a retention feature adjacent the ramp. A shaft includes a proximal portion that is rigid and defining a longitudinal axis, and a distal portion that is articulable. The shaft is configured to be removably disposed within a sheath. A pulling element is coupled to the distal portion and configured to be tensioned to move the introducer device from an unconstrained state in which the distal portion is oriented along the longitudinal axis, and a constrained state in which the distal portion is configured to assume a curve away from the longitudinal axis. An actuator is pivotably coupled to the handle and coupled to the pulling element. The actuator includes a control member defining a control surface, a resilient arm extending from the control member in a direction opposite the control surface so as to be disposed within the handle, and a lock head at an end of the resilient arm. The control surface is configured to receive an input from a user to pivotably move the control member towards the handle and the lock head towards the proximal opening. The resilient arm is configured to deflect as the lock head moves along the ramp, and return to an original state for releasable engagement between the lock head and the retention feature so as to lock the introducer device in the constrained state.

In certain implementations, the lock head extends through the proximal opening when the lock head engages the retention feature. The lock head may include a proximally-facing protrusion having a release surface configured to be actuated by a thumb of a hand of a user.

In some implementations, the actuator of the seventh aspect may be included with the introducer device of the systems according to the second, fourth, fifth and sixth aspects, and optionally, any of their corresponding implementations. The handle may be formed as a pistol grip having a frame from which the shaft extends. The frame includes shoulders defining a void configured to receive removably the sheath hub so as to prevent rotation of the sheath device relative to the introducer device. The pistol grip may include a handle and define a proximal surface of the handle. The proximal surface may be flattened and/or at least substantially planar so as to receive an impact from a surgical mallet. The handle may include indicia disposed on the proximal surface and configured to identify a direction of the curve of the distal portion with the introducer device in the constrained state.

An eighth of the disclosure is directed to a method of augmenting a vertebral body (not claimed). A distal end of an access cannula may be positioned within the vertebral body to provide access to an interior region of the vertebral body along a longitudinal axis. A handle of the introducer device is grasped. A shaft of the introducer device and the sheath are directed within the access cannula such that the distal portion of the introducer device and the distal portion of the sheath are beyond the distal end of the access cannula. The introducer device is operated by pivoting the control member relative to the handle to cause the pulling element to be tensioned to move the introducer device from an unconstrained state in which the distal portion of the shaft is oriented along the longitudinal axis, and a constrained state in which the distal portion is configured to assume a curve away from the longitudinal axis. A ramp of the handle is deflected as the resilient arm moves along the ramp and engages a retention feature of the handle. A release surface extending through the proximal opening is depressed to disengage the lock head from the retention feature to move the introducer device from the constrained state to the unconstrained state.

In some implementations, the method of the eigtht aspect may be included with the systems according to the second, fourth, fifth, sixth and seventh aspects, and optionally, any of their corresponding implementations.

A ninth aspect of the disclosure is directed to a sheath device for a system for augmenting a vertebral body. A sheath includes a proximal portion extending from a sheath hub along a longitudinal axis and comprising metal, and a distal portion comprising polymeric material. The proximal portion is coupled to the distal portion at an interface including a plurality of protrusions on each of the proximal portion and the distal portion configured to engage one another and provide a constant inner diameter and a constant outer diameter across the interface.

In certain implementations, the plurality of protrusions is disposed equiangularly about the longitudinal axis. Each of the plurality of protrusions may include a thinned region widening into a bulbous or circular profile. Alternatively, each of the plurality of protrusions on the proximal portion comprises a barb. Alternatively, each of the plurality of protrusions of the proximal portion comprises a tine that is wavy in shape.

In some implementations, the sheath of the ninth aspect may be included with the systems according to the second, fourth, fifth, sixth and seventh aspects, and optionally, any of their corresponding implementations.

A tenth aspect of the disclosure is directed to a system for augmenting a vertebral body. An access cannula includes a cannula hub, and a cannula shaft extending from the cannula hub. The cannula shaft includes a distal end positionable within the vertebral body and defining a lumen along a longitudinal axis. An introducer device includes an actuator, a shaft, and a pulling element. The actuator configured to receive an input from a user. The shaft includes a proximal portion that is rigid, and a distal portion. The pulling element is coupled to the actuator and to the distal portion. The pulling element configured to be tensioned to move the introducer device from an unconstrained state in which the distal portion is oriented along the longitudinal axis, and a constrained state in which the distal portion is configured to assume a curve away from the longitudinal axis. The shaft is removably disposed within a sheath. The sheath includes a distal end, a flexible region configured to be positioned along the distal portion of the shaft, and indicia disposed on the sheath. The access cannula and the introducer device have complementary lengths such that, when the indicia is in alignment with a proximal end of the cannula hub, the distal end of the sheath is in registration with the distal end of the access cannula.

In some implementations, the indicia of the tenth aspect may be included with the systems according to the second, fourth, fifth, sixth, seventh and ninth aspects, and optionally, any of their corresponding implementations.

An eleventh aspect of the present disclosure is directed to a method of augmenting a vertebral body (not claimed). A distal end of the access cannula is positioned within the vertebral body to provide access to an interior region of the vertebral body along a longitudinal axis. The shaft of the introducer device and the sheath are directed beyond the access cannula. The introducer device is operated to cause the distal portion of the shaft and the flexible region of the sheath to assume a curve within the interior region of the vertebral body. The introducer device is removed from the sheath device with the flexible region of the sheath remaining in the curve. A drill device is directed through the sheath device and resecting tissue within the vertebral body, thereby leaving a bore. The drill device is removed from the sheath device.

In certain implementations, an electrode shaft of an electrode probe is directed through the sheath. A probe may be exposed beyond the distal end of the sheath and within the bore. The probe is operated to ablate tissue within the vertebral body. An expandable member is directed through the sheath to be exposed beyond the distal end of the sheath and within the bore. The expandable member may be directed into the bore before or after ablation of the tissue. The expandable member may be inflated to provide a cavity within the vertebral body. The expandable member is deflated, and then removed from the sheath. Curable material through the sheath to within the cavity of the vertebral body.

In some implementations, the drill device, the electrode probe, and/or the cavity-forming device of the method according to the eleventh aspect may be included with the systems according to the second, fourth, fifth, sixth, seventh, ninth and tenth aspects, and optionally, any of their corresponding implementations.

A twelfth aspect of the present disclosure is directed to method of augmenting a vertebral body (not claimed). A distal end of an access cannula is positioned within the vertebral body to provide access to an interior region of the vertebral body along a longitudinal axis. A shaft of an introducer device and a sheath is directed beyond the access cannula. The introducer device is operated to cause the distal portion of the shaft and the flexible region of the sheath to assume a curve within the interior region of the vertebral body. The introducer device is removed from the sheath device with the flexible region of the sheath remaining in the curve. A biopsy device is directed through the sheath device and capture a tissue sample within the vertebral body. The biopsy device is removed from the sheath device.

In some implementations, the biopsy device of the method according to the twelfth aspect may be included with the systems according to the second, fourth, fifth, sixth, seventh, ninth, tenth aspects and eleventh, and optionally, any of their corresponding implementations.

A thirteenth aspect of the present disclosure is directed to method of augmenting a bone (not claimed). A distal end of an access cannula is positioned within the bone to provide access to an interior region of the bone along a longitudinal axis. A shaft of an introducer device and a sheath is directed beyond the access cannula. The introducer device is operated to cause the distal portion of the shaft and the flexible region of the sheath to assume a curve within the interior region of the bone. The introducer device is removed from the sheath device with the flexible region of the sheath remaining in the curve. An electrode shaft through the sheath, and the probe of the electrode device is exposed beyond the distal end of the sheath. The probe is operated to ablate tissue within the bone.

In certain implementations the bone is one of a vertebral body, a cranium, a long bone, and an ilium. The methods and systems according to the first through twelfth aspects may be operable to augment any bone of the body.

In certain implementations, methods and systems according to the first through thirteenth aspects may be operable to augment non-osseous anatomy, for example, ear, nose, and throat (ENT) or other difficult to access anatomy with straight instrumentation.

Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

<FIG> shows a system <NUM> for augmenting anatomy. The system <NUM> includes an introducer device <NUM>, an access cannula <NUM>, and a sheath device <NUM>. The system <NUM> may further include a treatment device (e.g., a cavity-forming device <NUM>) and a spacer lock <NUM>. As schematically represented by the broken lines of <FIG>, the certain components of the system <NUM> are removably couplable to and/or deployable through one another in a manner that facilitates off-axis access within the anatomy of interest. An exemplary procedure to be described throughout the present disclosure is augmentation of vertebral body for performing a vertebroplasty, kyphoplasty, ablation, biopsy, drilling and/or other related procedure. In certain implementations, the system <NUM> may be configured to augment other bones of the body, for example, a cranium, a long bone, and an ilium. Alternatively, the system <NUM> may be configured to augment non-osseous anatomy, for example, ear, nose, and throat (ENT) or other difficult to access anatomy with straight instrumentation.

The access cannula <NUM> includes a cannula hub <NUM>, and a cannula shaft <NUM> extending from the cannula hub <NUM>. The cannula shaft <NUM> includes a proximal end <NUM> coupled to the cannula hub <NUM>, and a distal end <NUM> opposite the proximal end <NUM>. The cannula shaft <NUM> may be straight and define a lumen (not identified) extending between the proximal and distal ends <NUM>, <NUM> such that the cannula shaft <NUM> is tubular in shape. The cannula shaft <NUM> may comprise or be formed from biocompatible materials with sufficient mechanical properties to maintain integrity as the cannula shaft <NUM> is driven through the pedicle of the vertebra. The system <NUM> may include a trocar (not shown) removably positioned within the cannula shaft <NUM> during placement of the distal end <NUM> of the cannula shaft <NUM> into the vertebral body. The trocar may include a length slightly greater than a length of the cannula shaft <NUM> such that a sharp tip of the trocar pierces the cortical bone of the cortical rim, and the trocar prevents coring of tissue within the lumen of the cannula shaft <NUM>. Once the distal end <NUM> of the cannula shaft <NUM> is positioned within the vertebral body, the trocar is removed. The access cannula <NUM> provides a working channel to within the interior region of the vertebral body along a longitudinal axis defined by the cannula shaft <NUM>. The cannula hub <NUM> is exposed above the tissue overlying the vertebra, and certain components of the system <NUM> are configured to be directed through the working channel of the access cannula <NUM>.

The introducer device <NUM> - to which the sheath device <NUM> may be removably coupled - may be directed within or through the access cannula <NUM>. The introducer device <NUM> may be actuated to form a curved path within the vertebral body with advancement of the introducer device <NUM> beyond the access cannula <NUM>. With reference to <FIG>, the introducer device <NUM> includes an actuator <NUM>, and a shaft <NUM> extending from the actuator <NUM>. The actuator <NUM> is configured to receive an input from a practitioner or user to actuate the introducer device <NUM> from an unconstrained state in which the shaft <NUM> of the introducer device <NUM> is straight and may be inserted or removed from the cannula shaft <NUM> of the access cannula <NUM>, respectively. The introducer device <NUM> is actuated from the unconstrained state to a constrained state in which a distal portion <NUM> of the shaft <NUM> is urged away from the longitudinal axis. <FIG> and <FIG> show the introducer device <NUM> in the unconstrained state, and <FIG> shows the introducer device <NUM> in the constrained state. The actuator <NUM> includes a housing <NUM>, and a control member <NUM> movably coupled to the housing <NUM>. The illustrated implementation shows the housing <NUM> and the control member <NUM> in a "pistol-grip" arrangement in which a handle <NUM> of the housing <NUM> is configured to rest in a palm of a hand of the practitioner, and the control member <NUM> configured to be pivotably pulled towards or released away from the handle <NUM> with one or more fingers of the hand of the practitioner. Other arrangements of the actuator <NUM> are contemplated, for example a rotary knob disclosed in <CIT>. A frame <NUM> may be integrally formed with and extend distal to (or forward of) the handle <NUM> in a generally L-shaped arrangement. As used herein, distal or distally refers to a direction away from the practitioner, and proximal or proximally refers to a direction towards the practitioner. The housing <NUM> may comprise mirrored housing shells <NUM>, <NUM> joined together, which may be manufactured from polymers, metals, composites, and combinations thereof. For example, each of the housing shells <NUM>, <NUM> may be injection molded so as to be low cost and disposable after a single use. The housing shells <NUM>, <NUM> may at least partially define an interior of the housing <NUM> sized and shaped to accommodate several components of the actuator <NUM> to be described.

Near its distal end, the frame <NUM> of the housing <NUM> may include shoulders <NUM> defining a slot <NUM> therebetween. One of the housing shells <NUM> includes one of the shoulders <NUM>, and the other one of the housing shells <NUM> includes the other one of the shoulders <NUM> such that the shoulders <NUM> are generally positioned at the three and six o'clock positions. The slot <NUM> is oriented vertically between the shoulders <NUM> and sized to receive a hub <NUM> of the sheath device <NUM>, as best shown in <FIG>. More particularly, the hub <NUM> of the sheath device <NUM> includes flats <NUM> (see also <FIG>) positioned adjacent a respective one of the shoulders <NUM> when the hub <NUM> is removably and slidably received within the slot <NUM> of the frame <NUM>. The resulting arrangement prevents rotation of the sheath device <NUM> relative to the introducer device <NUM>. As such, a hand of the practitioner is freed from separately having to maintain the rotational position of the sheath device <NUM> as he or she manipulates the introducer device <NUM> to a desired orientation. The resulting arrangement may further facilitate ease with retraction and removal of the introducer device <NUM> from the sheath device <NUM> after deployment within the vertebral body in a manner to be further explained. Still further, the resulting arrangement may prevent or twisting or kinking of the sheath device <NUM> as the practitioner manipulates the introducer device <NUM> in the constrained state against resistance of the cancellous bone in the vertebral body. The hub <NUM> of the sheath device <NUM> may further include wings <NUM> positioned between the flats <NUM> so as to be aligned with the slot <NUM> of the frame <NUM> when the hub <NUM> is removably and slidably received within the slot <NUM> of the frame <NUM>. The wings <NUM> may provide not only ergonomic surfaces for one or more fingers of the physician, but also a visual indication as to a direction of curvature of the introducer device <NUM> once actuated to the constrained state. Further indication of the direction of curvature of the introducer device <NUM> once actuated to the constrained state may be provided elsewhere on the housing <NUM>. In one implementation, indicia <NUM> such as a line may be positioned on a proximal side of the frame <NUM>. The indicia <NUM> and an upper one of the wings <NUM> may function as rear and forward sights, respectively - which are already within his or her field of view over the surgical site, to provide intuitive guidance to the practitioner. Additionally or alternatively, the indicia <NUM> may be positioned on one or both the wings <NUM> of the sheath device <NUM>. The indicia <NUM> may be on an upper one of the wings <NUM> corresponding to a direction of curvature of the flexible distal portion <NUM> of the sheath device <NUM>, as generally shown in <FIG>. Subsequent to removal of the introducer device <NUM> from the sheath device <NUM>, the indicia <NUM> being positioned on the wings <NUM> provide visual indication as to the direction of curvature of the flexible distal portion <NUM> within the vertebral body. By extension, the indicia <NUM> may provide further visual indication as to the direction that subsequent components directed through the sheath device <NUM> may be extend from the flexible distal portion <NUM>.

The proximal side of the frame <NUM> may include a flattened surface <NUM> (see <FIG>) configured to receive an impact force from a surgical mallet or the like. During deployment of the introducer device <NUM> beyond the distal end <NUM> of the access cannula <NUM>, it may be indicated to impact the flattened surface <NUM> with the mallet one or more times to facilitate channeling of the introducer device <NUM> through the cancellous bone of the vertebral body. Likewise, the impacting may facilitate channeling of the introducer device <NUM> through necrotic tissue or tumorous tissue that may be present within the vertebral body. The flattened surface <NUM> may be positioned proximal to the handle <NUM> to define a proximal end of the introducer device <NUM>. The flattened surface <NUM> may be at least substantially planar, and further may be at least substantially circular. The circularity of the flattened surface <NUM> may corresponding in shape and size to a head of the mallet, thus providing an intuitive indication of the appropriate location to impact the introducer device <NUM> with the surgical mallet. Further, with the frame <NUM> and the handle <NUM> forming the pistol grip, the user may firmly support the handle <NUM> in one hand while impacting the flattened surface <NUM> of the frame <NUM> with the mallet being held in the other hand.

The shaft <NUM> of the introducer device <NUM> includes a rigid proximal portion <NUM> and the flexible distal portion <NUM>. Referring now to <FIG> and <FIG>, the proximal portion <NUM> of the shaft <NUM> extends through a bore of the frame <NUM> to a position within the interior of the handle <NUM>. The proximal portion <NUM> of the shaft <NUM> may be axially and rotationally fixed relative to the actuator <NUM>. A retaining block <NUM> may be disposed within the interior of the handle <NUM> with a proximal end of the proximal portion <NUM> of the shaft <NUM> being secured to the retaining block <NUM>. The proximal portion <NUM> may be formed from rigid material(s) with sufficient mechanical properties to avoid more than minimal flexure.

The distal portion <NUM> extends from the proximal portion <NUM>. With further reference to <FIG> and <FIG>, a transition between the proximal portion <NUM> and the distal portion <NUM> may be defined by a first of a series of geometries within the shaft <NUM>. The series of geometries may provide a series of interconnected segments <NUM>. The interconnected segments <NUM> may be of unitary construction. In other words, the segments <NUM> may not be discrete links, but rather subportions of the distal portion <NUM> configured to articulate relative to one another. As a result, the shaft <NUM> including the proximal and distal portions <NUM>, <NUM> may comprise or be formed from a single piece of metal. In one implementation, the geometries may be laser cut into the single piece of metal. More particularly, the geometries may take the form of slots <NUM> defined within an upper side of the distal portion <NUM>. The slots <NUM> may be T-shaped as shown in <FIG>. The geometries may further include protrusions <NUM> corresponding to the shape of the slots <NUM>. The protrusions <NUM> may also be T-shaped. With the introducer device <NUM> in the unconstrained state and the distal portion <NUM> generally straight, gaps are between the protrusions <NUM> and an adjacent edge of the slots <NUM>. As the introducer device <NUM> is moved to the constrained state, the gaps between the protrusions <NUM> and the adjacent edges of the slots <NUM> are closed. Further tension provided by a pulling element <NUM> with the contact of the adjacent segments <NUM> provides rigidity to the distal portion <NUM>. The tension is sufficient for the introducer device <NUM> to assume and/or maintain a curve within the vertebral body with advancement of the distal portion <NUM> beyond the distal end <NUM> of the access cannula <NUM>.

The slots <NUM> and protrusions <NUM> may be disposed on an upper or concave side of the distal portion <NUM>, as generally appreciated from <FIG>. With further reference to <FIG>, extending from the slots <NUM> are first slits <NUM>, and the first slits <NUM> extend about a portion of the outer diameter of the distal portion <NUM>. The first slits <NUM> may be oriented transverse to the longitudinal axis. The first slits <NUM> of the illustrated implementation extend about a majority of the outer diameter. Further geometries may be disposed on a lower or convex side of the distal portion <NUM>, and those geometries may interconnect the segments <NUM>. More specifically, the first slits <NUM> terminate at second slits <NUM> to define spine sections <NUM> between opposing pairs of the second slits <NUM>. The second slits <NUM> may be angled relative to the first slits <NUM>, for example, at right angles such that the second slits <NUM> are oriented parallel to the longitudinal axis of the distal portion <NUM>. Owing to the flexibility of the material forming the distal portion <NUM>, the spine sections <NUM> are configured to flex. The flexure of the spine sections <NUM> is at least sufficient to permit the protrusions <NUM> to move within the slots <NUM> into contact with the adjacent edges as previously described. The resulting arrangement provides for relative movement of the segments <NUM> and, in the aggregate, articulation of the distal portion <NUM> over its length. The extent of articulation or curvature of the distal portion <NUM> may be selectively controlled through selective tensioning of the pulling element <NUM>. The angle of articulation or curvature may be designed within the range of approximately <NUM> to <NUM> degrees, and more particularly within the range of approximately <NUM> to <NUM> degrees, and even more particularly within the range of approximately <NUM> to <NUM> degrees. <FIG>, <FIG> and <FIG> show the distal portion <NUM> oriented at an angle of approximately <NUM> degrees relative to the proximal portion <NUM>. In alternative implementations, the reverse configuration is contemplated in which the slots <NUM> and protrusions <NUM> may be disposed on the lower or concave side of the distal portion <NUM>, and the first and second slits <NUM>, <NUM> are disposed on the upper or concave side of the distal portion <NUM>.

It is contemplated that the user may rotate the introducer device <NUM> during or after deployment of the distal portion <NUM> within the vertebral body in order to steer the distal portion <NUM> to a target location. Owing to the presence of cancellous bone within the vertebral body, the distal portion <NUM> including the segments <NUM> endure torqueing as the introducer device <NUM> is rotated. The segments <NUM> of the distal portion <NUM> may advantageously be designed to achieve the desired steerability while providing compliance or flexibility of the segments <NUM> to handle the torque. In certain implementations, lateral aspects of the slots <NUM> and/or lateral aspects of the protrusions <NUM> (see <FIG>) may be sized to define a gap of a specific size such that adjacent segments <NUM> may be free to rotate slightly relative to one another prior to the complementary lateral aspects engage one another. The "rotational play" between the adjacent segments <NUM> may limit torqueing on the segments <NUM> during initial rotation of the introducer device <NUM>. Once the complementary lateral aspects engage one another, the segments <NUM> become rigid in nature and preserve steerability with subsequent rotation of the introducer device <NUM>.

With the introducer device <NUM> being rotated in the constrained state, it should be appreciated that more proximal segments <NUM> endure more torque than more distal segments <NUM>. For example, the counteracting forces from the cancellous bone on a distal end <NUM> of the shaft <NUM> result in heightened torque on a proximal-most one of the segments <NUM> (i.e., adjacent the proximal portion <NUM>) with further rotation of the introducer device <NUM>. The introducer device <NUM> of the present disclosure advantageously contemplates varying the design of individual segments <NUM> to account for the gradient of anticipated torque along a length of the distal portion <NUM>. In one implementation, the aforementioned gaps between the complementary lateral aspects of the slots <NUM> and the protrusions <NUM> may decrease more distally along a length of the distal portion <NUM>. The arrangement results in more distal adjacent segments <NUM> being more rigid in function relative to more proximal adjacent segments <NUM> during rotation of the introducer device <NUM>. In another implementation and with reference to <FIG>, the spine sections <NUM> may be of varying widths along the length of the distal portion <NUM>. More particularly, the width of the spine sections <NUM> may progressively decrease distally along the length of the distal portion <NUM> such that the spine sections <NUM> of the proximal-most segments <NUM> are wider to endure greater torque. The reverse configurations of the gaps and/or the spine sections <NUM> are contemplated as well.

Referring again to <FIG> and <FIG>, the pulling element <NUM> is coupled to the actuator <NUM> and the shaft <NUM>, and more particularly the distal portion <NUM> of the shaft <NUM>. The pulling element <NUM> includes a proximal end coupled to the control member <NUM> of the actuator <NUM>. The pulling element <NUM> may be secured to the control member <NUM> with an interference connector <NUM>, for example a ferrule, nut, swaged sleeve, clamp, or other suitable connector. The connector <NUM> may be sized to movably ride within a slot defined by complementary pockets in each of the housing shells <NUM>, <NUM>. An input to the control member <NUM> (e.g., pulled towards the handle <NUM>) urges the connector <NUM> proximally within the slot, thereby tensioning the pulling element <NUM>.

The pulling element <NUM> includes a distal end coupled to the shaft <NUM> at or near its distal end <NUM>. The pulling element <NUM> extends through a lumen <NUM> of the shaft <NUM>, and may be joined at or near the distal end <NUM> of the shaft <NUM> through brazing, welding, adhesive, interference fit, or other suitable joining process. The distal end of the pulling element <NUM> may be coterminous with the distal end <NUM> of the shaft <NUM>. The pulling element <NUM> may be monolithic in construction and comprise or be formed from a metal, polymer, composite, or combination thereof. For example, the pulling element <NUM> may be a wire rope, a wire, a rod, and the like, of solid or hollow construction.

In certain implementations, the pulling element <NUM> may be coupled to the shaft <NUM> with a hypotube (not shown). The hypotube may have an inner diameter slightly greater than an outer diameter of the pulling element <NUM>, and an outer diameter slightly less than an inner diameter of the shaft <NUM>. The hypotube may have a length sized to be disposed within a distalmost of the interconnected segments <NUM>. In one example, the hypotube has a length of approximately three millimeters. The hypotube may be secured over a distal end of the pulling element <NUM>, for example, by crimping. The outer surface of the hypotube may then be welded or otherwise secured to the inner surface of the shaft <NUM>. The hypotube being crimped onto the pulling element <NUM> may preserve the tensile strength of the pulling element <NUM> relative to implementations where welding may anneal the pulling element <NUM> with corresponding reduction in tensile strength.

As previously mentioned, the pulling element <NUM> is configured to be selectively tensioned to alter the extent of the articulation or curvature of the distal portion <NUM>. With the introducer device <NUM> in the unconstrained state (see <FIG>), minimal or zero tension may be exerted on the pulling element <NUM>, also referred to herein as a first tension. It should be appreciated that some minimal tension may be on the pulling element <NUM> in the unconstrained state. The input to the control member <NUM> increases the tension on the pulling element <NUM> to move the introducer device <NUM> to the constrained state, also referred to herein as a second tension. The second tension is greater than the first tension.

The actuator <NUM> may be locked with the introducer device <NUM> in the constrained state. The actuator <NUM> may include a locking mechanism <NUM> for operably coupling the housing <NUM> and the control member <NUM> and configured to permit selective locking of the control member <NUM>. The locking mechanism <NUM> of the implementation shown in <FIG> and <FIG> provides for simplified, cost-effective construction and intuitive operation. Each of the shells <NUM>, <NUM> includes the handle <NUM> defines a proximal opening <NUM> and includes a ramp <NUM> and a retention feature <NUM> adjacent the ramp <NUM>. The ramp <NUM> and the retention feature <NUM> may define an upper portion of the proximal opening <NUM>, and the proximal opening <NUM> may be ergonomically positioned on the handle <NUM> to be easily accessible by the thumb of the practitioner when holding the actuator <NUM> of the introducer device <NUM> (see <FIG>). The locking mechanism <NUM> may further include an arm <NUM> coupled to and extending from the control member <NUM> in a direction opposite the control surface <NUM>. <FIG> and <FIG> show the arm <NUM> extending proximally from the control member <NUM> towards the handle <NUM>. A lock head <NUM> is at the end of the arm <NUM>. The arm <NUM> and lock head <NUM> are arranged and dimensioned such that, as the control member <NUM> is pivoted towards the handle <NUM> as the actuator <NUM> is actuated, the lock head <NUM> moves towards and assumes a position within the proximal opening <NUM>.

The lock head <NUM> is configured to releasably engage the retention feature <NUM> of the handle <NUM>. The arm <NUM> is resilient and configured to deflect as the lock head <NUM> moves along the ramp <NUM> of the handle <NUM>. More particularly, as the control member <NUM> is pivoted towards the handle <NUM>, an upper surface of the lock head <NUM> contacts the ramp <NUM>. The interference between the lock head <NUM> and the ramp <NUM> results in the arm <NUM> deflecting downwardly with further pivoting of the control member <NUM> with force sufficient to overcome the interference. A notch <NUM> on the lock head <NUM> moves past the ramp <NUM>, and the dimensions of the notch <NUM> permit the arm <NUM> to resiliently return to an original state in which the notch <NUM> engages the retention feature <NUM>, as shown in <FIG>. The resilient return of the arm <NUM> is sudden, and the lock head <NUM> contacting the retention feature <NUM> may result in an audible and/or tactile feedback to the practitioner. Particularly when the actuator <NUM>, including the control member <NUM>, the handle <NUM>, the arm <NUM>, and the lock head <NUM> are formed from plastic, the plastic-on-plastic impact may make a sound audible to the practitioner. Along those lines, the locking mechanism <NUM> of the present disclosure provides for a low-cost design that is more easily manufacturable than, for example, a ratchet mechanism. It should be understood that the other suitable mechanism for selectively locking the introducer device <NUM> in the constrained state are contemplated. One suitable example is described in <CIT>, in which a ratchet is configured to be selectively locked one of a plurality of positions corresponding to different tensions on the pulling element and different angles of curvature of the steering instrument.

With the locking mechanism <NUM> locked, the tension of the pulling element <NUM> is maintained, and thus the introducer device <NUM> is maintained in the constrained state. As mentioned, the lock head <NUM> extends through the proximal opening <NUM>. The lock head <NUM> includes a release surface <NUM> positioned proximal to the proximal opening <NUM> so as to be engageable by the thumb of the practitioner. In manners to be described, once the introducer device <NUM> is actuated and positioned within the vertebral body, the workflow includes the step of removing the introducer device <NUM> from the sheath device <NUM>. The introducer device <NUM> should be moved to the unconstrained state to do so, otherwise the curvature of the distal portion <NUM> - having rigidity from the tension of the pulling element <NUM> are previously explained - would prevent the practitioner from removing the introducer device <NUM> from the sheath device <NUM>. In an ergonomic and intuitive step, the practitioner may simply engage the release surface <NUM> and urge the lock head <NUM>, against the bias of the arm <NUM>, out of engagement with the retention feature <NUM>. The residual tension on the pulling element <NUM> may urge the control member <NUM> distally, and the introducer device <NUM> assumes the unconstrained state. The lock head <NUM> may no longer be within the proximal opening <NUM>, providing a visual indication of the practitioner that the locking mechanism <NUM> has been disengaged and the introducer device <NUM> is in the unconstrained state.

As previously mentioned, the introducer device <NUM> may be operably coupled to the sheath device <NUM> when deployed into the vertebral body, and the workflow may include the step of removing the introducer device <NUM> from the sheath device <NUM>. Subsequently, components of the system <NUM> may be deployed through the sheath device <NUM>. Referring now to <FIG>, the sheath device <NUM> includes the hub <NUM>, and a sheath <NUM> extending from the hub <NUM>. The hub <NUM> may include a fitting <NUM> in communication with a lumen <NUM> of the sheath <NUM> and configured to be removably coupled with another component of the system <NUM>. One exemplary fitting is a Luer fitting.

At least a region of the sheath <NUM> is flexible and configured to conform to the shaft <NUM>, and more particularly to the distal portion <NUM> of the shaft <NUM> as the introducer device <NUM> moved from the constrained state to the unconstrained state. With concurrent reference to <FIG>, the flexible region <NUM> extends from a proximal portion <NUM> of the sheath <NUM>. The proximal portion <NUM> is coupled to and extends distally from the hub <NUM>, and the proximal portion <NUM> may be flexible or rigid. In the illustrated implementation, the proximal portion <NUM> is rigid and comprise or be formed from biocompatible materials with sufficient mechanical properties to maintain integrity as the sheath device <NUM> is retracted and advanced in a manner to be described. One exemplary material is stainless steel. The flexible region <NUM> may be coupled to or integrally formed with the proximal portion <NUM>. In one example, the flexible region <NUM> may be a separate component joined with the proximal portion <NUM> at a lap joint. The flexibility of the flexible region <NUM> may be due to a helical pattern extending between opposing ends <NUM> of the flexible region <NUM>. The helical pattern may be formed by laser cutting or other suitable manufacturing process, and it is to be understood that a helix is one exemplary geometry.

Each of the flexible region <NUM> and the proximal portion <NUM> defines a portion of the lumen <NUM>. With the shaft <NUM> of the introducer device <NUM> disposed within the lumen <NUM> of the sheath <NUM> of the sheath device <NUM>, the flexible region <NUM> of the sheath <NUM> is axially aligned with the distal portion <NUM> of the shaft <NUM>. As a result, providing an input to the actuator <NUM> to move the introducer device <NUM> from the unconstrained state to the constrained state, the flexible region <NUM> of the sheath <NUM> assumes a curve corresponding to the articulation or curvature of the distal portion <NUM> of the shaft <NUM>. As the flexible region <NUM> of the sheath <NUM> assumes the curve within the vertebral body, portions of the helical pattern may become spaced apart. In other words, small gaps may become present on the convex side of the helical pattern. As to be described, however, curable material - which is initially flowable - is to be directed through the sheath <NUM> of the sheath device <NUM>. It may not be desirable for egress of the curable material through the small gaps, as the target location is generally considered to be at a distal end <NUM> of the sheath <NUM>. Stated differently, it is generally desirable for the curable material to be directed through and out of the lumen <NUM> at the distal end <NUM> of the sheath <NUM>. The sheath <NUM> of the present disclosure advantageously prevents such egress by including a sleeve <NUM> coaxially disposed within or exterior to the flexible region <NUM> of the sheath <NUM>. As best shown in <FIG>, the sleeve <NUM> is coupled to the sheath <NUM> at or near the opposing ends <NUM> of the flexible region <NUM>. The sleeve <NUM> is polymeric so as to have the necessary elasticity and flexibility to traverse the curve assumed by the flexible region <NUM>. Whereas <FIG> shows the sleeve <NUM> disposed within the flexible region <NUM>, a reverse configuration is contemplated in which the sleeve <NUM> is disposed on an exterior of the flexible region <NUM>. In operation, the curable material being directed through the sheath <NUM> encounters the sleeve <NUM> so as to traverse the curve to be directed through the lumen <NUM> at the distal end <NUM> of the sheath <NUM>.

In certain implementations, the sleeve <NUM> may be preformed with a curve. The preformed curve may facilitate the flexible region <NUM> to curve when the introducer device <NUM> is removed from the sheath device <NUM>. Additionally or alternatively, the flexible region <NUM> of the sheath <NUM> may be preformed with a curve. The preformed curve may also facilitate the flexible region <NUM> to curve when the introducer device <NUM> is removed from the sheath device <NUM>. For example, the flexible region <NUM> may be metal, and the preformed curve may be plastically deformed during manufacturing of the sheath <NUM>. For another example, the preformed curve of the metal may be facilitated with the geometries such as the helix. The preformed curve of the flexible region <NUM> and/or the sleeve <NUM> may be designed with a curvature within the range of approximately <NUM> to <NUM> degrees, and more particularly within the range of approximately <NUM> to <NUM> degrees, and even more particularly within the range of approximately <NUM> to <NUM> degrees. In one implementation, the preformed curve may be approximately <NUM> degrees. The preformed curve may advantageously facilitate the sheath <NUM> traversing the curved path within the cancellous bone during advance of the sheath <NUM> with the introducer device <NUM>. The curved path may be created with more reproducibility, as there is less reliance on the introducer device <NUM> in the constrained state. In other words, the introducer device <NUM> and the sheath device <NUM> cooperate by each providing a portion of the lateral forces to impart the curve within the cancellous bone. Additionally, the preformed curve may advantageously facilitate the sheath <NUM> traversing the curved path within the cancellous bone during advance of the sheath <NUM> without the introducer device <NUM>. For example, after deployment and removal of the cavity-forming device <NUM> and prior to the deployment of curable material to within the cavity, it may be desirable to advance of the sheath <NUM> to a distal margin of the cavity. The preformed curve may avoid the distal end <NUM> of the sheath <NUM> "bottoming out" or snagging the convex side of the curved path and/or the cavity.

Referring now to <FIG>, the flexible region <NUM> may comprise or be formed from a flexible biocompatible polymer having sufficient hoop strength to patent upon removal of the introducer device <NUM> from the sheath <NUM>. Suitable flexible polymers include polypropylene, polyether ether ketone (PEEK), and the like. More particularly, the polymeric region <NUM> is coupled to the proximal portion <NUM> at an interface <NUM> having protrusions <NUM> resulting in a constant contour of the lumen <NUM> (i.e., the inner diameter), as best shown in <FIG>, and a constant outer diameter. The protrusions <NUM> include complementary fingers or tines configured to be joined to one another. An adhesive or other joining process may also be utilized to strengthen the interface <NUM>. The protrusions <NUM> may be radially disposed about the polymeric region <NUM> and the proximal portion <NUM>. The protrusions <NUM> may be further disposed equiangularly about the longitudinal axis. <FIG> show each of the protrusions having a neck <NUM>, and a head <NUM> larger than the neck <NUM>. The neck <NUM> may be a thinned region widening into a bulbous or circular profile defining the head <NUM>. The head <NUM> engaging the neck <NUM> of an adjacent one of the fingers <NUM> provides an axial retention force. Alternative implementations are shown in <FIG> shows each side of the tines <NUM> including serrations <NUM> to provide a barb. <FIG> shows every other neck <NUM> is longer so that the heads <NUM> are axially staggered. <FIG> shows the tines being wavy in shape and tapering to a point.

In another implementation, an entirety of the sheath <NUM> may comprise or be formed from a flexible biocompatible polymer having sufficient hoop strength to patent upon removal of the introducer device <NUM> from the sheath <NUM>. In other words, from distal to the hub <NUM> to the distal end <NUM>, the sheath <NUM> may be polymeric. Suitable flexible polymers include polypropylene, polyether ether ketone (PEEK), and the like. The implementation of the sheath <NUM> formed entirely from the flexible biocompatible polymer may also include a preformed curve. A heat-based process may impart the preformed curve in the polymer. The preformed curve may facilitate the flexible region <NUM> to curve when the introducer device <NUM> is removed from the sheath device <NUM>. Additionally or alternatively, the flexible region <NUM> of the sheath <NUM> may be preformed with a curve. The preformed curve may also facilitate the flexible region <NUM> to curve when the introducer device <NUM> is removed from the sheath device <NUM>. The preformed curve may be a curvature within the range of approximately <NUM> to <NUM> degrees, and more particularly within the range of approximately <NUM> to <NUM> degrees, and even more particularly within the range of approximately <NUM> to <NUM> degrees. In one implementation, the preformed curve may be approximately <NUM> degrees. Further, the polymer sheath <NUM> may include a reinforcement, such as braiding and/or coiling, with metal or other polymers. The polymer sheath <NUM> being of unitary construction may provide simplified design and/or reduced manufacturing costs. Still further, the polymer sheath <NUM> may be filled with a radiopaque material, such as barium or tungsten. With polymers being less visible on fluoroscopy, and the entirety of the sheath <NUM> being a polymer, the radiopaque material may be particularly well suited to facilitate real-time visual guidance with fluoroscopy subsequent to removal of the introducer device <NUM> from the sheath device <NUM>.

A workflow of performing a vertebral augmentation with the system <NUM> will now be described with particular reference to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. The vertebra with the offending vertebral body may be confirmed on fluoroscopic imaging. An incision may be made in the overlying paraspinal musculature lateral of midline generally in alignment with one of the pedicles of the vertebra. The distal end <NUM> of the access cannula <NUM>, with the trocar disposed therein, is directed through the pedicle a position beyond the cortical rim and within the interior region of the vertebral body, and the trocar is removed. The access cannula <NUM> provides the working channel to within the interior region of the vertebral body along the longitudinal axis. The cannula hub <NUM> is exposed and configured to be engaged by the introducer device <NUM>.

The shaft <NUM> of the introducer device <NUM> has a length sufficient to extend through and be operable beyond the distal end <NUM> of the access cannula <NUM>. Likewise, the sheath <NUM> of the sheath device <NUM> has a length sufficient to extend through and be operable beyond the distal end <NUM> of the access cannula <NUM>, and the length of the shaft <NUM> may further extend through the distal end <NUM> of the sheath <NUM>. <FIG> shows the distal end <NUM> of the shaft <NUM> being slightly distal to the distal end <NUM> of the sheath <NUM>. Each of the distal ends <NUM>, <NUM> may include a reverse bevel to facilitate penetration of the cancellous bone during deployment of the system <NUM>. The bevel may be fabricated through electrochemical grind, electrical discharge machining (EDM), or other suitable manufacturing process. With the introducer device <NUM> operably coupled to the sheath device <NUM> and the components positioned near in operable engagement with the cannula hub <NUM> of the access cannula <NUM>, as shown in <FIG>, the distal portion <NUM> of the introducer device <NUM> and the flexible region <NUM> of the sheath <NUM> is configured beyond the distal end <NUM> of the cannula shaft <NUM>.

The workflow includes directing the shaft of the introducer device <NUM> and the sheath <NUM> to within the access cannula <NUM> such that the distal portion <NUM> of the introducer device <NUM>. The introducer device <NUM> is in the unconstrained state in which the pulling element <NUM> is at the first tension that is zero or near zero. Furthermore, the flexible region <NUM> of the sheath <NUM> remains within the access cannula <NUM>. In other words, the distal ends <NUM>, <NUM> of the shaft <NUM> and the sheath <NUM> are positioned proximal to or in registration with the distal end <NUM> of the access cannula <NUM>. This may be facilitated with indicia <NUM> disposed on the sheath <NUM> (see <FIG>). The indicia <NUM> may be aligned with the hub <NUM> of the access cannula <NUM> such that, when the indicia <NUM> is in alignment with a proximal end of the cannula hub <NUM>, the distal end <NUM> of the sheath <NUM> is in registration with the distal end <NUM> of the access cannula <NUM>. Thereafter, an input is provided to the actuator <NUM> to move the introducer device <NUM>, for example, pivoting the control member <NUM> towards the handle <NUM>. The pivoting of the control member <NUM> to which the pulling element <NUM> is coupled, moves the introducer device <NUM> from the unconstrained state to the constrained state in which the pulling element <NUM> is at the second tension greater than the first tension. As previously described, this would otherwise result in the distal portion <NUM> of the introducer device <NUM> being articulated and the flexible region <NUM> of the sheath <NUM> assuming a curve from the longitudinal axis; however, the access cannula <NUM> prevents the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> from doing so. An appreciable amount of potential energy is stored in the pulling element <NUM> at the second tension.

The physical characteristics of the pulling element <NUM> (e.g., modulus of elasticity) is such that the locking mechanism <NUM> of the introducer device <NUM> may be actuated to the locked state despite the cannula shaft <NUM> constraining the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> from assuming the curve. As previously described, the arm <NUM> of the locking mechanism <NUM> flexes until the lock head <NUM> passes the ramp <NUM>, and resiliently returns to provide interface engagement between the notch <NUM> and the retention feature <NUM>. An audible and/or tactile indication may be provided to the practitioner that the introducer device <NUM> is locked in the constrained state. The lock head <NUM> is positioned thorough the proximal opening <NUM> as shown in <FIG>.

Prior to or after moving the introducer device <NUM> from the unconstrained state to the constrained state, the introducer device <NUM> and the sheath device <NUM> may be rotated relative to the access cannula <NUM> onto a desired, anticipated plane of curvature (once advanced within the vertebral body). The handle <NUM> may be rotated, and owing to the engagement of the flats <NUM> of the hub <NUM> and the shoulders <NUM> of the frame <NUM>, the sheath device <NUM> is correspondingly rotated. The desired plane of curvature may be provided by the indicia <NUM> on the proximal side of the frame <NUM> and/or the wings <NUM> of the hub <NUM>.

Thereafter, the introducer device <NUM> and the sheath device <NUM> are advanced relative to the access cannula <NUM> with the introducer device <NUM> in the constrained state. The distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> are moved distally beyond the distal end <NUM> of the access cannula <NUM> to within the vertebral body. The pulling element <NUM> is at the second tension and, as the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> are moved beyond the distal end <NUM> of the access cannula <NUM>, the stored potential energy causes the distal portion <NUM> of the shaft <NUM> to articulate or curve. The flexible region <NUM> of the sheath <NUM> correspondingly assumes the curve. The advancement may be characterized the components plunging through cancellous bone of the vertebral body while simultaneously assuming the curve. The result is shown in <FIG>. The distal ends <NUM>, <NUM> of the shaft <NUM> and the sheath <NUM> are positioned at the target site offset from the longitudinal axis.

Thereafter, it is indicated to remove introducer device <NUM> from the sheath device <NUM> with the distal end <NUM> of the sheath <NUM> remaining positioned at the target site offset from the longitudinal axis. The lumen <NUM> of the sheath <NUM> provides a pathway to the target site to locations within the vertebral body with the pathway facilitating the remaining steps of the vertebral augmentation procedure. Owing to the tension on the pulling element <NUM> and the slot <NUM> and protrusion <NUM> engagement, the distal portion <NUM> of the shaft <NUM> has rigidity that prevents removal of the shaft <NUM> from the sheath <NUM>. Therefore, it may be indicated to lessen or remove the tension from the pulling element <NUM>. The locking mechanism <NUM> is actuated from the locked state to the unlocked state. In particular, an input is provided to the release surface <NUM> to disengage the lock head <NUM> from the retention feature <NUM>, and the pulling element <NUM> at least substantially returns to the first tension. Owing to the presence of cancellous bone within which the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> have assumed a curve, moving the locking mechanism <NUM> to the unlocked state may not result in the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath <NUM> returning to a straight. The introducer device <NUM>, however, moves from the constrained state to the unconstrained state, whereby pulling element <NUM> being at the first tension provides for removal of the introducer device <NUM> from the sheath device <NUM> with the flexible region <NUM> of the sheath <NUM> remaining curved within the vertebral body. The result in shown in <FIG>.

The position of the distal end <NUM> of the sheath <NUM> may be confirmed via fluoroscopy. The sheath <NUM> being metal may be visible on fluoroscopy, and in implementations using the polymer region, one exemplary manner to confirm the position includes radiopaque markers as disclosed in <CIT>. Should the position of the distal end <NUM> be suboptimal prior to removal of the introducer device <NUM> from the sheath device <NUM>, the system <NUM> advantageously facilitates repositioning of the sheath device <NUM> without requiring the sheath device <NUM> be removed from the access cannula <NUM> to be redeployed. Existing systems may require removal of the sheath device <NUM>, which may undesirably increase the likelihood of material degradation of the sheath <NUM>. For example, in cases where a sheath is formed only from a polymer such as PEEK, there may be pronounced frictional forces on the sheath from the distal end <NUM> of the access cannula <NUM> as it is being removed. With the system <NUM> including the introducer device <NUM>, the practitioner may provide another input to the actuator <NUM> to increase the tension the pulling element <NUM> while the distal portion <NUM> of the shaft <NUM> and the flexible region <NUM> of the sheath device <NUM> are within the interior region of the vertebral body. The practitioner may manipulate the handle <NUM> as desired, then return the introducer device <NUM> to the unconstrained state at a second or subsequent target site that is offset from the longitudinal axis. It is understood that any number of subsequent inputs may be provided to the control member <NUM>, and multiple inputs may be provided for creating a cavity of a desired shape within the interior region of the vertebral body.

In certain implementations, it may be desirable to reposition the sheath <NUM> after removal of the introducer device <NUM> from the sheath <NUM>. With the introducer device <NUM> in the unconstrained state, the shaft <NUM> may be redirected through the sheath <NUM> that is already positioned within the vertebral body. Once the introducer device <NUM> is deployed, the input(s) may be provided to and removed from the control member <NUM> of the actuator <NUM> to tension the pulling element <NUM> and reposition the sheath <NUM> at the second or subsequent target site. The shaft <NUM> of the introducer device <NUM> may again be removed from the sheath <NUM> with the sheath <NUM> remaining positioned at the second or subsequent target site offset from the longitudinal axis.

With the introducer device <NUM> removed from the sheath device <NUM> and with the distal end <NUM> of the sheath <NUM> remaining positioned at the target site offset from the longitudinal axis, the treatment device may be deployed through the sheath device <NUM>. The treatment device may be a cavity-forming device <NUM> configured to displace tissue as part of a kyphoplasty procedure. Additionally or alternatively, the treatment device may be an electrode probe <NUM> device configured to ablate tissue. Other vertebral augmentation components are contemplated, for example, a drill device and/or a tissue biopsy device. The treatment device is directed through the sheath device <NUM> and near or in registration with the distal end <NUM> of the sheath <NUM>, after which the sheath <NUM> is retracted relative to the component to expose the component at the target location. In order to facilitate the retraction of the sheath <NUM> in an ergonomic and intuitive manner, the system <NUM> includes the spacer lock <NUM>. Referring now to <FIG>, the spacer lock <NUM> includes legs <NUM> extending from a hub <NUM> and defining at least one slot <NUM>. The illustrated implementation includes two of the slots <NUM>. A distal end <NUM> of the legs <NUM> are configured to be removably positioned in abutment with an engagement surface <NUM> of the hub <NUM> of the access cannula <NUM>. With the access cannula <NUM> generally extending upwardly from the back of the patient positioned prone on the operative table, the spacer lock <NUM> is configured to rest upon the engagement surface <NUM> under the influence of gravity without any additional coupling mechanism. Further, the slots <NUM> are sized and shaped to slidably receive the wings <NUM> of the hub <NUM> of the sheath device <NUM>. A distance between the legs <NUM> may be larger than a distance between the flats <NUM> of the hub <NUM> of the access cannula <NUM> such that, with the wings <NUM> of the hub <NUM> slidably received within the slots <NUM>, each of the legs <NUM> is disposed adjacent a respective one of the flats <NUM>.

The hub <NUM> of the access cannula <NUM> may include at least one handle <NUM> extending from and positioned proximal to the engagement surface <NUM>. The handle <NUM> extends between opposing sides of the hub <NUM>, as best shown in <FIG>. The distal end <NUM> of the legs <NUM> are configured to be removably positioned in abutment with the engagement surface <NUM> of the hub <NUM> adjacent the handle <NUM>. Further, the hub <NUM> of the sheath device <NUM> is configured to be disposed within the slots <NUM> of the spacer lock <NUM>, the spacer lock <NUM> is prevented from "tipping," laterally or otherwise, relative to the access cannula <NUM>. As a result, despite the spacer lock <NUM> not being fixedly or removably secured to the access cannula <NUM> (i.e., without any additional coupling mechanism), movement of the spacer lock <NUM> relative to the access cannula <NUM> is constrained in four degrees of freedom. The two degrees of freedom by which the spacer lock <NUM> may move relative to the access cannula <NUM> is proximal translation during removal of the spacer lock <NUM>, and rotation about a longitudinal axis of the sheath device <NUM>. The resulting arrangement is shown in <FIG>. It is contemplated that each of the spacer lock <NUM> and the hub <NUM> of the access cannula <NUM> may include complementary coupling features (not shown), for example a releasable detent, configured to removably couple the spacer lock <NUM> to the access cannula <NUM>.

The cavity-forming device <NUM> may be packaged as operably coupled to the spacer lock <NUM>. The hub <NUM> of the spacer lock <NUM> defines an aperture <NUM> in communication with a void between the legs <NUM>. The aperture <NUM> may be centered on the hub <NUM> and configured to be coaxially aligned with the fitting <NUM> of the hub <NUM> of the sheath device <NUM> and a fitting <NUM> of the hub <NUM> of the access cannula <NUM>, as shown in <FIG>. The aperture <NUM> is sized to receive the component of the system <NUM>, in this case, a tube <NUM> of the cavity-forming device <NUM>. Thus, the tube <NUM> extends through the aperture <NUM>, and an expandable member <NUM> is directed through the fitting <NUM> of the hub <NUM> of the sheath device <NUM> and guided through the lumen <NUM> as the spacer lock <NUM> is moved into engagement with the access cannula <NUM>. Alternatively, it is contemplated that the cavity-forming device <NUM> is not operably coupled to the spacer lock <NUM>, and the spacer lock <NUM> may be positioned in engagement with the access cannula <NUM>, after which the expandable member <NUM> is directed through the aperture <NUM>, followed by the tube <NUM> and the fitting <NUM> of the hub <NUM>. In either implementation of the workflow, the resulting arrangement is shown in <FIG>.

The cavity-forming device <NUM> may include a support member <NUM> extending along at least a portion of the tube <NUM>. As best shown in <FIG>, the support member <NUM> is coaxially arranged on an outer diameter of the tube <NUM>. In certain implementations, the support member <NUM> may extend from near the hub <NUM> to a location positioned distal the spacer lock <NUM> when the spacer lock <NUM> is positioned in engagement with the hub <NUM> of the access cannula <NUM>. More particularly, the support member <NUM> may extend from a position proximal to the aperture <NUM> of the spacer lock <NUM> to a position distal to the fitting <NUM> of the sheath device <NUM> when the spacer lock <NUM> is positioned in engagement with the hub <NUM> of the access cannula <NUM>. Whereas the tube <NUM> of the cavity-forming device <NUM> may be flexible, the support member <NUM> may be relatively rigid. In one example, the support member <NUM> is formed from a metal and/or hard polymer. As a result, the support member <NUM> effectively prevents the spacer lock <NUM> from "tipping," laterally or otherwise, relative to the access cannula <NUM>, especially with the spacer lock <NUM> configured to rest upon the engagement surface <NUM> of the access cannula <NUM> generally extending upwardly from the back of the patient positioned prone on the operative table without any additional coupling mechanism.

With further reference to <FIG>, the tube <NUM> extends from a hub <NUM>, and the expandable member <NUM> is disposed at a distal end of the tube <NUM>. The hub <NUM> includes a fitting adapted to be coupled with a fluid line in communication with a source of incompressible fluid (not shown), for example, air. The expandable member <NUM> is configured to receive fluid from the source of fluid through the hub <NUM> and the tube <NUM> to be moved between a deflated state and an inflated state having a volume greater than the deflated state. In the deflated state, the expandable member <NUM> and the tube <NUM> are sized to be slidably inserted or directed through the lumen <NUM> of the sheath <NUM>. A combined length of the tube <NUM> and the expandable member <NUM> may be approximately equal to the length of the sheath <NUM> such that, with the hub <NUM> positioned adjacent the hub <NUM> of the spacer lock <NUM>, a distal end of the expandable member <NUM> is in registration with the distal end <NUM> of the sheath <NUM>. Alternatively, the combined length may be such that the expandable member <NUM> is positioned beyond the distal end <NUM> of the sheath <NUM>. The expandable member <NUM> is moved to the inflated state to compress or otherwise displace cancellous bone within the vertebral body at the target site. Returning the expandable member <NUM> to the deflated state may result in a cavity being formed within the cancellous bone for delivery of the curable material (see <FIG>).

The tube <NUM> and/or the expandable member <NUM> are sufficiently flexible to follow the pathway defined by the lumen <NUM> of the sheath <NUM>, including the flexible region <NUM> in the curved configuration. In other words, directing the expandable member <NUM> through the sheath <NUM> should not alter the curvature of the flexible region <NUM> of the sheath <NUM>. Owing to the flexibility of the tube <NUM> and/or the expandable member <NUM>, the cavity-forming device <NUM> may lack sufficient columnar strength to be advanced beyond the distal end <NUM> of the sheath <NUM> to penetrate the cancellous bone of the interior region. Additionally or alternatively, urging the cavity-forming device <NUM> to penetrate the cancellous bone may result in the trabeculae of the cancellous bone causing the expandable member <NUM> to deviate from the desired path previously created by the introducer device <NUM> and/or the target site previously accessed by the introducer device <NUM>. The system <NUM> of the present disclosure advantageously provides for moving the sheath <NUM> relative to the cavity-forming device <NUM> in a manner to unsheathe and sheathe the expandable member <NUM>. The spacer lock <NUM> provides for the unsheathing and sheathing the expandable member <NUM> with a syringe-style input that is both ergonomic and intuitive to the practitioner. The presence of the support member <NUM> facilitates the syringe-style input by supporting the tube <NUM> of the cavity-forming device <NUM> above a proximal side of the spacer lock <NUM>.

The spacer lock <NUM>, in cooperation with the hub <NUM> of the sheath device <NUM>, facilitates the syringe-style input. With continued reference to <FIG> and <FIG>, the spacer lock <NUM> is configured to facilitate proximal and distal movement of the sheath <NUM> relative to the access cannula <NUM> while maintaining a position of the cavity-forming device <NUM> relative to the access cannula <NUM>. The result includes proximal and distal movement of the sheath <NUM> including the sheath <NUM> relative to the cavity-forming device <NUM> including the expandable member <NUM>, hence unsheathing and sheathing the expandable member <NUM>, respectively. It is to be understood that the spacer lock <NUM> is an optional feature of the system <NUM>, and more conventional methods may also be utilized.

<FIG> shows the sheath device <NUM> in a first position in which the hub <NUM> of the sheath device <NUM> is near the hub <NUM> of the access cannula <NUM>, and the flexible region <NUM> is exposed beyond the distal end <NUM> of the access cannula <NUM>. The distal end of the expandable member <NUM> is in registration with the distal end <NUM> of the sheath <NUM> such that the expandable member <NUM> is at least partially disposed within the flexible region <NUM> of the sheath <NUM>. The hub <NUM> of the spacer lock <NUM> includes at least one grip surface <NUM>. The hub <NUM> may include two grip surfaces <NUM> positioned opposite the aperture <NUM>. The grip surfaces <NUM> are sized to be engaged by a thumb of the practitioner, and the grip surfaces <NUM> may include raised features configured to facilitate the same. The wings <NUM> of the hub <NUM> are oriented parallel to the grip surfaces <NUM>, and the wings <NUM> are configured to be engaged by finger(s) of the practitioner. In one example, one of the wings <NUM> is configured to be engaged by the index finger of the practitioner, the other one of the wings <NUM> is configured to be engaged by the middle finger of the practitioner. With the thumb concurrently engaging one of the grip surfaces <NUM>, the result is the aforementioned syringe-style input. The syringe-style input is economic and well-known to practitioners. As a result, the practitioner may intuitively squeeze the fingers towards the thumb to move the hub <NUM> and the sheath <NUM> from the first position to a second position in which the hub <NUM> is positioned relative to the first position. As shown in <FIG>, the hub <NUM> of the sheath device <NUM> is positioned nearer or adjacent to the hub <NUM> of the spacer lock <NUM> in the second position. The hub <NUM> may be moved a desired distance, and/or a set distance until contacting the hub <NUM> of the spacer lock <NUM>. The set distance may correspond to at least the distance required to unsheathe the expandable member <NUM> based on its length. The movement of the sheath <NUM> relative to the access cannula <NUM> and the cavity-forming device <NUM> exposes the expandable member <NUM> at the target site. The expandable member <NUM>, as shown, occupies the curve previously assumed by the flexible region <NUM> of the sheath <NUM>. The expandable member <NUM> remains on the curve owing to the curved path created during deployment of the introducer device <NUM> as well as the cancellous bone defining the curved path. The expandable member <NUM> is unsheathed and exposed within the interior region of the vertebral body in the deflated state, after which the expandable member <NUM> may be moved to the inflated state to displace the cancellous bone.

The expandable member <NUM> is returned to the deflated state to form the cavity within the cancellous bone for delivery of the curable material (see <FIG>). The expandable member <NUM> is sheathed. In one example, with the expandable member <NUM> deflated, the hub <NUM> is moved from the second position to the first position in which the flexible region <NUM> again is exposed beyond the distal end <NUM> of the access cannula <NUM> and the expandable member <NUM> is again at least partially disposed within the flexible region <NUM> of the sheath <NUM>. In another example, a proximal input may be provided to the expandable member hub <NUM> to move moving the expandable member <NUM> into and through the sheath <NUM>, after which the hub <NUM> is moved from the second position to the first position to reassume the curve with the distal end <NUM> of the sheath <NUM> is at the target site. With the expandable member <NUM> sheathed, it may be removed from the access cannula <NUM>.

A vertebral augmentation kit including the introducer device <NUM>, the access cannula <NUM>, the sheath device <NUM>, the spacer lock <NUM>, and the cavity-forming device <NUM>. In certain implementations, the kit may include more than one cavity-forming device <NUM>. In particular, each of the cavity-forming devices <NUM> may include an expandable member <NUM> of a different dimension, which may be selectively deployed based on a desired cavity size and/or anatomical dimensions of the vertebral body of the patient. For example, the kit may include three cavity-forming devices <NUM> having expandable members <NUM> with axial length of <NUM> millimeters (mm), <NUM> millimeters, and <NUM> millimeters. Given that the sheath <NUM> of the sheath device <NUM> has a fixed length, the differing lengths of the expandable members <NUM> may necessitate selective adjustment of the cavity-forming device <NUM> relative to the sheath device <NUM> in order to properly unsheathe the expandable member <NUM>. Additionally or alternatively, the spacer lock <NUM> of the present system <NUM> advantageously provides for maintaining a selective position of the cavity-forming device <NUM> during unsheathing of the expandable member <NUM>. As such, the practitioner may selectively position the expandable member <NUM> (and/or treatment device) contralaterally, midline, or ipsilaterally, and the spacer lock <NUM> maintains the position as the practitioner performs other steps of the vertebral augmentation procedure.

Referring now to <FIG>, the spacer lock <NUM> includes the hub <NUM>, and the legs <NUM> extending from the hub <NUM>. The hub <NUM> defines the aperture <NUM>, and the legs <NUM> define the void space in communication with the aperture <NUM>. The hub <NUM> includes a lower housing <NUM> from which the legs <NUM> extend, and an upper housing <NUM> secured to the lower housing <NUM>. A lock mechanism <NUM> is operably coupled to the lower and upper housings <NUM>, <NUM>, and includes a lock actuator <NUM>. The lock mechanism <NUM> includes a biasing element <NUM>, for example, a torsion spring shown in <FIG>. The lock actuator <NUM> may be a U-shaped component including an input surface <NUM> and a first lock surface <NUM>. The lock actuator <NUM> is pivotally coupled to the hub <NUM>, in particular the lower and upper housings <NUM>, <NUM>. The lower housing <NUM> includes a second lock surface <NUM>. The first and second lock surfaces <NUM>, <NUM> at least partially surround the aperture <NUM> of the lower housing <NUM>. The biasing element <NUM> is operably coupled to the lower housing <NUM> and the lock actuator <NUM>, and the biasing element <NUM> is configured to bias the lock actuator <NUM> to a closed state in which a shaft of the treatment device is effectively squeezed between the first and second lock surfaces <NUM>, <NUM>. The torsion spring biases the first lock surface <NUM> towards the second lock surface <NUM> to engage the shaft of the treatment device.

The lock actuator <NUM>, in particular the input surface <NUM>, is configured to receive an input from a user to selectively permit movement of the treatment device relative to the access cannula <NUM> or the sheath device <NUM>. With continued reference to <FIG>, the input to the input surface <NUM> pivots the lock actuator <NUM> against the bias of the biasing element <NUM> to move the lock mechanism from the closed state to an open state in which the distance between the first and second lock surfaces <NUM>, <NUM> is increased. The increase in distance lessens or eliminates the squeezing on the treatment device, after which the treatment device may be selectively moved relative to the spacer lock <NUM>. For example, the input surface <NUM> may be actuated with one hand of the practitioner, and with the other hand the practitioner proximally retracts the treatment device. Once positioned as desired, the practitioner merely removed the input to the input surface <NUM>, after which the biasing element <NUM> returns the lock mechanism <NUM> from the open state to the closed state in which movement of the treatment device is again prevented.

<FIG> shows another implementation of the spacer lock <NUM>. The lock mechanism <NUM> includes the lock actuator <NUM> having the input surface <NUM>, and the biasing element <NUM> operably coupled to the lock actuator <NUM> and the hub <NUM>. The biasing element <NUM> may be a disc <NUM> having an opening and slots <NUM>, <NUM> extending radially from the opening. The disc <NUM> may be coupled to the lower housing <NUM> such that the opening is coaxially aligned with the aperture <NUM>. One of the slots <NUM> extends to the outer edge of the disc <NUM>, and the other slots <NUM> result in thinned regions of the disc <NUM> that are configured to resiliently deflect when engaged by the lock actuator <NUM>. In a natural or closed state, a size of the opening is slightly smaller than a shaft of the treatment device such that the treatment device is prevented from moving relative to the spacer lock <NUM>. The shaft of the treatment device is effectively "pinched" between tips of flanges defined by the slots <NUM>, <NUM>. For example, the tips of flanges defined by the slots <NUM>, <NUM> pinches the support member <NUM> of the cavity-forming device <NUM>.

The lock actuator <NUM> is slidably coupled to the hub <NUM>. The lock actuator <NUM> may include rails <NUM> configured to engage slots <NUM> of the lower housing <NUM>. A pin (not shown) slidably disposed with a cavity <NUM> permits the slidable movement of the lock actuator <NUM> relative to the lower housing <NUM>, but prevents the lock actuator <NUM> from decoupling from the same. The lock actuator <NUM> may include a protrusion <NUM> shaped complementary to the slot <NUM>. In the illustrated implementation, the slot <NUM> and the protrusion <NUM> are complementarily triangular when viewed in plan. In the natural or closed state, the protrusion <NUM> is positioned within the slot <NUM>, and the position of the shaft of the treatment device is maintained by engagement of the tips of flanges defined by the slots <NUM>, <NUM>. For example, the tips of flanges defined by the slots <NUM>, <NUM> pinches the support member <NUM> of the cavity-forming device <NUM>. An input may be provided to the input surface <NUM> to move the lock mechanism <NUM> from the natural or closed state to the open state in which movement of the treatment device is permitted relative to the spacer lock <NUM>. The lock actuator <NUM> is slidably moved relative to the hub <NUM>, and the protrusion <NUM> forces the thinned regions of the disc <NUM> to resiliently deflect, for example, radially outward relative to the aperture <NUM>. The resilient deflection of the thinned regions results in a diameter of the opening to increase in the open state by an extent sufficient to permit movement of the shaft of the treatment device relative to the spacer lock <NUM>. Once the treatment device has been moved to the desired position, the input to the input surface <NUM> is removed. The potential energy stored in the resiliently deflected thinned regions of the disc <NUM> is released, and the lock actuator <NUM> is slidably moved relative to the hub <NUM> to an initial position. The lock mechanism <NUM> is returned to the natural or closed state, after which further movement of the treatment device relative to the spacer lock <NUM> is prevented. The above steps may be repeated as many times as desired.

An exemplary workflow of the spacer lock <NUM> will now be described in the context of the cavity-forming device <NUM> during a kyphoplasty procedure. The introducer device <NUM> and the sheath device <NUM> are deployed, and the introducer device <NUM> is removed from the sheath device <NUM>. The cavity-forming device <NUM> is directed through the aperture <NUM> of the spacer lock <NUM> either before or after operably positioning the spacer lock <NUM> in engagement with the hub <NUM> of the access cannula <NUM>. With the hub <NUM> engaging the hub <NUM> of the spacer lock <NUM>, the distal end of the expandable member <NUM> may be in registration with the distal end <NUM> of the sheath <NUM>. The lock mechanism <NUM> is in the closed state such that engagement of the tube <NUM> by the lock actuator <NUM> prevents movement of the cavity-forming device <NUM> relative to the spacer lock <NUM> (and thus also relative to the access cannula <NUM> and the sheath device <NUM>). Using the syringe-style input, the expandable member <NUM> is unsheathed in a contralateral position within the vertebral body. In particular, because the spacer lock <NUM> engages the support member <NUM> and/or the tube <NUM>, moving the hub <NUM> of the sheath device <NUM> within the slots <NUM> of the spacer lock <NUM> results in corresponding movement of the distal end <NUM> of the sheath <NUM> to expose the expandable member <NUM> at the target site. The expandable member <NUM> is inflated to create a cavity within the vertebral body. In one example, the practitioner may wish to create a second cavity that is positioned ipsilaterally to the midline. After resheathing the expandable member <NUM>, the input is provided to the input surface <NUM> of the spacer lock <NUM> to move the lock mechanism <NUM> from the closed state to the open state. With the lock mechanism <NUM> in the open state, another input provided to the hub <NUM> proximally retracts the cavity-forming device <NUM> to the desired position. The input is released, and the lock mechanism <NUM> returns to the closed state. Again, using the syringe-style input, the expandable member <NUM> is unsheathed in the ipsilateral position within the vertebral body. During both instances where the expandable member <NUM> is unsheathed, the practitioner need not separately maintain the position of the cavity-forming device <NUM>, thereby freeing him or her to focus on other aspects of the procedure.

In another example with the cavity-forming device <NUM>, the practitioner may decide that the <NUM>-millimeter expandable member is indicated. Given the relative size of the expandable member <NUM> relative to the vertebral body, it may be necessary to position the expandable member <NUM> on the midline of the vertebral body. As mentioned, however, the distal end <NUM> of the sheath <NUM> may be positioned contralaterally when deployed, and the distal end of the expandable member <NUM> may be in registration with the distal end <NUM> of the sheath <NUM>. In order to position the expandable member <NUM> on the midline of the vertebral body, a slight proximal retraction of the cavity-forming device <NUM> may be indicated. The spacer lock <NUM> facilitates the proximal retraction of the cavity-forming device <NUM> without the practitioner needing to manually maintain its position, which is particularly beneficial during the subsequent unsheathing the expandable member <NUM> on the midline.

Another exemplary workflow of the spacer lock <NUM> will now be described in the context of an electrode probe <NUM> during a tissue ablation procedure. Referring to <FIG>, the electrode probe <NUM> may include a hub <NUM>, a shaft <NUM>, and at least one emitter <NUM> at the end of the shaft <NUM>. The electrode probe <NUM> is configured to be coupled to a source of electrical energy, and to provide the energy at the target site to ablate tissue. The tissue to be ablated may be a tumor, a nerve, or the like. In one example, the tissue may be the basivertebral nerve having a main branch that extends anteriorly to within the vertebral body generally along the midline of the same. As such, with the introducer device <NUM> configured to access contralateral positions within the vertebral body, the system <NUM> is well suited to ablate the basivertebral nerve. The introducer device <NUM> and the sheath device <NUM> are deployed, and the introducer device <NUM> is removed from the sheath device <NUM>. The electrode probe <NUM> is directed through the aperture <NUM> of the spacer lock <NUM> either before or after operably positioning the spacer lock <NUM> in engagement with the hub <NUM> of the access cannula <NUM>. With the electrode hub <NUM> engaging the hub <NUM> of the spacer lock <NUM>, the distal end of the emitter(s) <NUM> may be in registration with the distal end <NUM> of the sheath <NUM>. This contralateral positioning of the emitter(s) <NUM> may be suboptimal for ablation of the basivertebral nerve. As a result, the input is provided to the input surface <NUM> of the spacer lock <NUM> to move the lock mechanism <NUM> from the closed state to the open state. With the lock mechanism <NUM> in the open state, another input provided to the electrode hub <NUM> to adjust the emitter(s) <NUM> to the desired position. The input is released, and the lock mechanism <NUM> returns to the closed state. Using the syringe-style input, the emitter(s) <NUM> is unsheathed in the desired position within the vertebral body. The emitter(s) <NUM> is powered to supply electrical energy to ablate the basivertebral nerve.

It is understood that the ablation of tissue is an optional step, and it may occur before or after creation of the cavity with the cavity-forming device <NUM>. Further, it may be desirable to drill a bore within the vertebral body prior to or after positioning of the emitter(s) <NUM> and/or the expandable member <NUM> of the cavity-forming device <NUM>. For example, the introducer device <NUM>, the sheath device <NUM>, the cavity-forming device <NUM>, and/or any other component of the system <NUM> may encounter a bone tumor. In order to access within the tumor for optimal placement of the emitter(s) <NUM>, a drill device <NUM> may be directed through the sheath <NUM>. <FIG> shows the drill device <NUM> including a handpiece <NUM>, a shaft <NUM> extending from the handpiece <NUM>, and a drill tip <NUM> coupled to the shaft <NUM>. The shaft <NUM> includes a flexible region configured to navigate the curve assumed by the flexible region <NUM> of the sheath <NUM>. The drill device <NUM> may be deployed beyond the distal end <NUM> of the sheath <NUM>, and operated to resect the tumor. The drill device may be powered or manual. One exemplary drill device is the MicroFX Osteochondral Drilling (OCD) system manufactured by Stryker Corporation (Kalamazoo, Mich. A manual drill device may include a knurled handle. The introducer device <NUM>, the sheath device <NUM>, the cavity-forming device <NUM>, and/or any other component of the system <NUM> may encounter necrotic tissue. In order to access within the vertebral body for optimal placement of the emitter(s) <NUM> for ablation of the basivertebral nerve, the drill device <NUM> may be used in the aforementioned manner. It is understood that the drill device <NUM> and corresponding workflow steps are optional. It is further contemplated that a biopsy needle may be used in the aforementioned manner to obtain a tissue sample for biopsy. The biopsy needle may include a flexible region configured to navigate the curve assumed by the flexible region <NUM> of the sheath <NUM>. The biopsy needle may be deployed beyond the distal end <NUM> of the sheath <NUM>, and operated to, for example, obtain a core sample of the tumor.

The workflow may include delivering curable material (also known as bone cement) to within the vertebral body. This may be done with or without creating a cavity to receive the curable material. A curable material delivery system suitable for use with the system <NUM> of the present disclosure is described in commonly-owned International Patent Publication No. <CIT>, and <CIT>, and sold under the tradename PCD System by Stryker Corporation (Kalamazoo, Mich. Still another suitable cement delivery system is disclosed in commonly owned <CIT>.

Referring to <FIG>, the cement delivery system may include a tube <NUM> and a coupler <NUM> is adapted to be coupled to the fitting <NUM> of the sheath hub <NUM>, as shown in <FIG>. Curable material is delivered through the sheath <NUM> to the target site. During the delivery the curable material, the hub <NUM> of the sheath device <NUM> may be moved from the first position to the second position such that the sheath <NUM> may be proximally retracting while the curable material is being delivered in a retrograde manner. The sheath <NUM> is removed from the access cannula <NUM>. The trocar may be reintroduced through the access cannula <NUM>, and the access cannula <NUM> and trocar removed from the vertebral body. The overlying tissue may be sutured.

Referring now to <FIG>, various configurations for deploying the treatment device within the vertebral body with a bipedicular approach are illustrated. As previously discussed, certain aspects of the disclosure are directed to accessing the contralateral side of the vertebral body through a unipedicular approach. For another example, certain aspects of the present disclosure are directed to accessing the midline through a unipedicular approach for ablation of the basivertebral nerve. Utilizing the bipedicular approach in which there are two of the systems <NUM> of the present disclosure advantageously provides access to nearly all regions of the interior of the vertebral body. The illustrated figures show a schematic representation of the treatment device within the vertebral body, for example, after being deployed through the sheath <NUM> as previously explained. In a preferred implementation, the treatment device is representative of the electrode probe <NUM> previously described, in which the emitters <NUM> of each of the electrode probes <NUM> are configured to be deployed in complementary configurations within the vertebral body to effectuate desired heating patterns once operated. One exemplary electrode probe that is sufficiently flexible for navigating the curved distal portion is described in <CIT>. The electrode probe <NUM> may be bipolar or monopolar. It is contemplated that the electrode probe <NUM> may be irrigated such that a fluid is infused into the adjacent tissue prior to and/or during ablation. It is further contemplated that the electrode probe <NUM> may be cooled, for example, by circulating a fluid within pathways internal to the electrode probe <NUM>.

<FIG> illustrates a bipedicular approach in which each of the systems <NUM> are used to deploy the treatment devices ipsilaterally. Should this be known preoperatively, the angle of approach on the pedicles themselves may be adjusted owing to the curve anticipated to be assumed by the system <NUM> and ultimately the treatment device. Should this be desired after the access cannula <NUM> (and trocar) are deployed within the pedicle of the vertebral body, then adjustments may be made to the position the distal end <NUM> of the access cannula <NUM> at a specific point within the (bony) pedicle in anticipation of the curve of the introducer device <NUM>, which, in certain implementations, is known and reproducible. <FIG> shows each of the treatment devices positioned ipsilaterally and symmetrical about the midline of the vertebral body. Further, ends of the treatment devices are substantially in the same position in the anterior-posterior direction. <FIG> show each of the treatment devices positioned substantially in the same position in the caudio-cranial direction.

<FIG> illustrate a bipedicular approach in which the systems <NUM> are used to deploy one of the treatment devices ipsilaterally and the other one of the treatment devices contralaterally. The treatment device deployed ipsilaterally is on-axis, whereas the treatment device deployed contralaterally is curved in manners previously described. <FIG> shows the end of the on-axis treatment device positioned anteriorly relative to the end of the off-axis treatment device. The reverse configuration is contemplated. <FIG> shows the end of the on-axis treatment device positioned cranially relative to the end of the off-axis treatment device. The reverse configuration is contemplated.

<FIG> illustrate a bipedicular approach in which each of the systems <NUM> are used to deploy the treatment devices contralaterally. The treatment devices are deployed off-axis and may be considered to overlap in the medio-lateral direction. <FIG> shows the end of one the treatment devices positioned anteriorly relative to the end of the other treatment device. The reverse configuration is contemplated. <FIG> show each of the treatment devices positioned substantially in the same position in the caudio-cranial direction.

Claim 1:
A system (<NUM>) for augmenting a vertebral body, the system comprising:
an access cannula (<NUM>) comprising a cannula hub (<NUM>), and a cannula shaft (<NUM>) extending from the cannula hub (<NUM>) with the cannula shaft (<NUM>) comprising a distal end (<NUM>) positionable within the vertebral body and defining a lumen along a longitudinal axis;
an introducer device (<NUM>) comprising a shaft (<NUM>) comprising a distal portion (<NUM>) configured to be curved when deployed beyond the distal end (<NUM>) of the cannula shaft (<NUM>);
a sheath device (<NUM>) comprising a sheath hub (<NUM>), and a sheath (<NUM>) extending from the sheath hub (<NUM>), wherein the shaft (<NUM>) is removably disposed within the sheath (<NUM>); and
a spacer lock (<NUM>) configured to facilitate proximal movement of the sheath (<NUM>) relative to the access cannula (<NUM>), the spacer lock (<NUM>) comprising legs (<NUM>) configured to be positioned in abutment with the cannula hub (<NUM>), and defining at least one slot (<NUM>) sized to slidably receive the sheath hub (<NUM>).