Patent Description:
This invention pertains generally to generating passageways through tissue, and more particularly to creating curved paths in bone.

Recently, the technique of accessing the vertebral body through minimally invasive means has been developed through the surgical techniques used in vertebroplasty and kyphoplasty. Although accessing the vertebral segments of the spine through the pedicle and into the lateral / anterior section of the body of the vertebra is the primary method of placing a treatment device (e.g. a bone cement delivery device and/or an RF probe) into the vertebra, it is difficult to place a probe in the posterior midline section of the vertebra. Furthermore, accessing the posterior midline section of the S1 segment of the spine is difficult with a straight linear access route. A probe preferably needs to be capable of navigating to the posterior section of the S1 vertebral body as well as the same target area within a lumbar vertebral segment. In addition, it is contemplated that spinal segments in the cervical and thoracic spine may also be targeted.

In order to accurately and predictably place a treatment device in the posterior midline section of a lumbar vertebral body or S1 vertebral body, the device or probe needs to navigate to said area through varying densities of bone. However due to the varying densities of bone, it is difficult to navigate a probe in bone and ensure its positioning will be in the posterior midline section of the vertebral body.

<CIT> discloses means to insert instrumentation necessary for performing percutaneous diskectomy using laser energy to vaporize nucleus pulposus within a lumbar disc of the vertebral column.

Current techniques for tissue aspirations require a coaxial needle system that allows taking several aspirates through a guide needle without repositioning the guide needle. However the problem with this system is that after the first pass of the inner needle in to the lesion, subsequent passes tend of follow the same path within the mass, yielding only blood not diagnostic cells.

A scientific paper written by <NPL>," describes the use of a side exiting coaxial needle to allow for several aspiration biopsies. The guide needle has a side hole <NUM> from the distal tip. When a smaller needle is advanced through this new guide needle, the smaller needle is deflected by a ramp inside the guide, causing the smaller needle to exit through the side hole. Although this side exiting needle is able to deflect a bone aspiration needle, it does not guarantee that the needle exits the side hole in a linear direction into the tissue site. Once the tissue aspiration needle exits the needle, it will deviate from a linear path depending on the density of the tissue and inherent material strength of the needle. This is an inherent problem the device is unable to overcome.

Accordingly, an object of the present invention is a system for generating a path in bone that predictably follows a predetermined curved path.

The present invention is directed to systems to deploy and navigate a flexible treatment instrument, such as an RF bipolar probe, within bone. Although the systems described below are primarily directed to navigating bone through a vertebral member of the spine, and particularly to treat the BVN of a vertebral member, it is appreciated that the novel aspects of the present invention may be applied to any tissue segment of the body.

The first novel principle of this invention is the ability to navigate a curve or angle within varying densities of cancellous bone and create a straight channel at the end of the navigated curve or angle. Several systems are described.

The invention comprises a system for channeling a path into bone. The system comprises a trocar having a central channel and opening at its distal tip, and a cannula sized to be received in said central channel and delivered to said distal opening. The cannula has a deflectable tip with a preformed curve such that the tip straightens while being delivered through the trocar and regains its preformed curve upon exiting and extending past the distal opening of the trocar to generate a curved path in the bone corresponding to the preformed curve of the deflectable tip. The cannula comprises a central passageway having a diameter configured allow a treatment device to be delivered through the central passageway to a location beyond the curved path.

According to the invention, the system further includes a straight stylet configured to be installed in the trocar, wherein the straight stylet comprises a sharp distal tip that is configured to extend beyond the distal opening of the trocar to pierce the bone as the trocar is being delivered to a treatment location within the bone.

The system may further include a straightening stylet configured to be installed in the cannula, wherein the straightening stylet comprising a rigid construction configured to straighten the distal tip of the cannula when positioned in the trocar.

The straightening stylet further comprises a sharp distal end to pierce the bone, and the straightening stylet and cannula are installed in the trocar in place of the straight stylet as the trocar is delivered into the bone.

A method (not claimed) consist of inserting a trocar into a region of bone comprises inserting a stylet into the trocar such that the stylet extends beyond the distal opening of the trocar, and inserting the stylet and trocar simultaneously into the region of bone such that the stylet pierces the bone as the trocar is being delivered to a treatment location.

In another example, delivering a cannula through the central channel comprises inserting a straightening stylet into the central passageway of the cannula, wherein the straightening stylet comprises a rigid construction configured to straighten the curved distal tip of the cannula, and inserting the straightening stylet and straightened cannula simultaneously into the trocar.

In an alternative example, the straightening stylet further comprises a sharp distal end to pierce the bone, wherein the straightening stylet and cannula are installed simultaneously along with the trocar as the trocar is delivered into the bone.

Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only:.

Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in <FIG>. It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein.

<FIG> and <FIG> illustrate a first embodiment of the present invention comprising a system or kit <NUM> for forming a path through bone. The system comprises a having a needle trocar <NUM> (the main body of the instrument set). The trocar <NUM> comprises an elongate shaft <NUM> having a handle <NUM> at its proximal end <NUM> and a central lumen <NUM> passing through to the distal end <NUM> of the trocar <NUM>. The central lumen <NUM> is generally sized to allow the other instruments in the system <NUM> to be slideably introduced into the patient to a treatment region. System <NUM> further comprises a straight stylet <NUM> having a sharp-tipped needle <NUM> at its distal end that is used with the needle trocar <NUM> to create the initial path through the soft tissue and cortical shell to allow access to the cancellous bone, a curved cannula <NUM> that is used to create/maintain the curved path within the bone/tissue. A straightening stylet <NUM> is used to straighten out the curve and load the curved cannula <NUM> into the needle trocar <NUM>. A curved stylet <NUM> is used in conjunction with the curved cannula <NUM> to create the curved path within the bone/tissue, and a channeling stylet <NUM> is used to create a working channel for a treatment device (such as RF probe <NUM>) beyond the end of the curved path created by the curved cannula <NUM>.

The surgical devices and surgical systems described may be used to deliver numerous types of treatment devices to varying regions of the body. Although the devices and systems of the present invention are particularly useful in navigating through bone, it is appreciated that they may also be used to navigate through soft tissue, or through channels or lumens in the body, particularly where one lumen may branch from another lumen.

The following examples illustrate the system <NUM> applied to generating a curve bone path in the vertebral body, and more particularly for creating a bone path via a transpedicular approach to access targeted regions in the spine. In particular, the system <NUM> may be used to deliver a treatment device to treat or ablate intraosseous nerves, and in particular that basivertebral nerve (BVN). Although the system and methods provide significant benefit in accessing the BVN, it is appreciated that the system <NUM> of the present invention may similarly be used to create a bone path in any part of the body.

<FIG> illustrates a cross-sectional view of a vertebra <NUM>. Recently, the existence of substantial intraosseous nerves <NUM> and nerve branches <NUM> within human vertebral bodies ("basivertebral nerves") have been identified. The nerve basivertebral <NUM> has at least one exit <NUM> point at a location along the nerve <NUM> where the nerve <NUM> exits the vertebral body <NUM> into the vertebral foramen <NUM>.

Preferably, the basivertebral nerves are at, or in close proximity to, the exit point <NUM>. Thus, the target region of the BVN <NUM> is located within the cancellous portion <NUM> of the bone (i.e., to the interior of the outer cortical bone region <NUM>), and proximal to the junction J of the BVN <NUM> having a plurality of branches <NUM> (e.g. between points A and B along nerve <NUM>). Treatment in this region is advantageous because only a single portion of the BVN <NUM> need be effectively treated to denervate or affect the entire system. Typically, treatment in accordance with this example can be effectuated by focusing in the region of the vertebral body located between <NUM>% (point A) and <NUM>% (point B) of the distance between the anterior and posterior ends of the vertebral body. In contrast, treatment of the BVN <NUM> in locations more downstream than the junction J require the denervation of each branch <NUM>.

In one approach for accessing the BVN, the patient's skin is penetrated with a surgical instrument which is then used to access the desired basivertebral nerves, i.e., percutaneously. In one example, a transpedicular approach is used for penetrating the vertebral cortex to access the BVN <NUM>. A passageway <NUM> is created between the transverse process <NUM> and spinous process <NUM> through the pedicle138 into the cancellous bone region <NUM> of the vertebral body <NUM> to access a region at or near the base of the nerve <NUM>. It is appreciated that a postereolateral approach (not shown) may also be used for accessing the nerve.

<FIG> illustrate a preferred method for accessing the BVN with the system <NUM> of the present invention. First, the straight stylet <NUM> is inserted in aperture <NUM> at the proximal end <NUM> of needle trocar <NUM>. The straight stylet <NUM> is advanced down the central lumen <NUM> (see <FIG>) of the trocar <NUM> until the proximal stop <NUM> abuts against handle <NUM> of the trocar <NUM>, at which point the distal tip <NUM> of straight stylet protrudes out of the distal end <NUM> of the trocar <NUM>. The tip <NUM> of the straight stylet <NUM> preferably comprises a sharp tip for piercing soft tissue and bone.

Referring now to <FIG>, the assembly (trocar <NUM> and straight stylus <NUM>) is advanced through soft tissue to the surface of the bone. Once the proper alignment is determined, the assembly is advanced through the cortical shell of pedicle <NUM> and into the cancellous interior <NUM> of the bone.

After the proper depth is achieved, the straight stylet <NUM> is removed from the trocar <NUM>, while the trocar <NUM> remains stationary within the vertebrae <NUM>. The straightening stylet <NUM> is inserted into proximal aperture <NUM> (see <FIG>)of the curved cannula <NUM> and advanced along the central lumen of the curved cannula <NUM> until the stop <NUM> of the stylet <NUM> abuts up to the proximal end of the curved cannula. This forces the distal tip of the straight stylet through the curved section <NUM> of the curved cannula <NUM> to straighten out the curve <NUM>. It is contemplated that the straight stylet comprise a hard, non-compliant material and the distal end <NUM> of the curved cannula <NUM> a compliant, yet memory retaining material (e.g. Nitinol, formed PEEK, etc.) such that the curved <NUM> section yields to the rigidity of the straightening stylet <NUM> when installed, yet retains its original curved shape when the stylet <NUM> is removed.

As shown in <FIG>, once the straightening stylet <NUM> is secure and the curved cannula <NUM> is straight, they are inserted into the needle trocar <NUM> and secured. Proper alignment (e.g. prevent rotation, orient curve direction during deployment) is maintained by aligning a flat on the upper portion <NUM> of the curved cannula <NUM> to an alignment pin secured perpendicularly into the needle trocar <NUM> handle <NUM>. Once the curved cannula <NUM> is secure, the straightening stylet <NUM> is removed, while the curved cannula <NUM> remains stationary within the trocar <NUM>.

Referring to <FIG>, the curved stylet <NUM> is then straightened out by sliding the small tube <NUM> proximally to distally on its shaft towards the distal tip <NUM> or from the distal tip <NUM> proximally on its shaft towards the proximal end <NUM>. Once the curved distal tip <NUM> is straightened out and fully retracted inside the small tube <NUM>, the curved stylet <NUM> is inserted into the proximal aperture <NUM> of the curved cannula <NUM>, which still resides inside the needle trocar <NUM>. As the curved stylet <NUM> is advanced into the curved cannula <NUM>, the small tube <NUM> is met by a stop <NUM> (see <FIG>). As the curved stylet <NUM> continues to advance the small tube <NUM> is held inside the handle of the curved cannula <NUM>. This allows the curve of the stylet <NUM> to be exposed inside the curved cannula <NUM>. To create the maximum force the curve of the two parts (<NUM> & <NUM>) must be aligned. To ensure alignment the cap on the curved stylet <NUM> has an alignment pin <NUM> which engages with alignment notch <NUM> on the proximal end of the curved cannula <NUM>.

Once the stylet <NUM> is fully seated and aligned with the curved cannula <NUM> the tip of the curved stylet <NUM> will protrude from the tip of the curved cannula <NUM> by about <NUM> to <NUM> (<NUM>/<NUM> to <NUM>/<NUM> inches). This protrusion will help to drive the curve in the direction of its orientation during deployment.

Referring now to <FIG>, with the curved stylet <NUM> and the curved cannula <NUM> engaged, the locking nut <NUM> at the top of the curved cannula <NUM> is rotated counter clockwise to allow the cannula <NUM> and stylet <NUM> to be advanced with relation to the needle trocar <NUM> such that the proximal end <NUM> about against <NUM>, advancing the curved cannula <NUM> and stylet <NUM> beyond the distal opening of trocar <NUM> to generate a curved path in the cancellous bone region <NUM>. As the curved cannula <NUM> and stylet <NUM> are advanced they will preferably curve at a radius of <NUM> to <NUM> (<NUM> to <NUM> inches). through cancellous bone and arc to an angle between <NUM> and <NUM> degrees. Once the curved cannula <NUM> and stylet <NUM> are deployed to the intended angle, the locking nut at the top of the curved cannula <NUM> is engaged with the needle trocar <NUM> to stop any additional advancement of the curved stylet cannula assembly.

Referring to <FIG> illustrate the tip of the curvet stylet <NUM>, which has been formed with two angles. To help the curve deployment in the proper direction the curve <NUM> of the curved stylet <NUM> is shaped in a predetermined orientation. The angle on the inside of the curve <NUM> is less than the angle on the outside of the curve <NUM>. This disparity in angle helps the stylet cannula assembly <NUM> & <NUM> curve in the bone as bone pushes against outside curve face <NUM> ensuring the curve radius is maintained during deployment.

Referring now to <FIG>, the curved stylet <NUM> is then removed and replaced by the channeling stylet <NUM>. The tip <NUM> of the channeling stylet <NUM> is advanced beyond the end <NUM> of the curved cannula <NUM> towards the intended target treatment zone.

Referring now to <FIG>, once the channeling stylet <NUM> reaches the target treatment zone, it is removed creating a working channel <NUM>. Channel <NUM> will generally have a first section <NUM> that crosses the cortical bone of the pedicle <NUM>, followed by a curved path <NUM>. These sections are occupied by curved cannula <NUM> such that a treatment device fed through the cannula <NUM> will have to follow the curve of the cannula <NUM> and not veer off in another direction. The channel may further comprise the linear extension <NUM> in the cancellous bone <NUM> to further advance the treatment device toward the treatment site T.

With the trocar <NUM> and curved cannula <NUM> still in place, a treatment device (e.g. treatment probe <NUM> shown in <FIG>, with an active element <NUM> on the distal end <NUM> of elongate flexible catheter <NUM> is delivered to the target treatment location T to perform a localized treatment.

In an example, the active element <NUM> is delivered to the treatment site and activated to delivery therapeutic treatment energy. The treatment probe may comprise an RF delivery probe having bipolar electrodes <NUM> and <NUM> that deliver a therapeutic level of heating to stimulate or ablate the nerve <NUM>.

It is appreciated that any number of treatment modalities may be delivered to the treatment site for therapeutic treatment. For example, treatment may be affected by monopolar or tripolar RF, ultrasound, radiation, steam, microwave, laser, or other heating means. Additionally, the treatment device may comprise a fluid delivery catheter that deposits an agent, e.g. bone cement, or other therapeutic agent, to the treatment site T. Alternatively, cryogenic cooling may be delivered for localized treatment of the BVN. Furthermore, treatment may be affected by any mechanical destruction and or removal means capable of severing or denervating the BVN. For example, a cutting blade, bur or mechanically actuated cutter typically used in the art of orthoscopic surgery may be used to affect denervation of the BVN.

In addition to or separate from treating the BVN, a sensor may be delivered to the region to preoperatively or postoperatively measure nerve conduction at the treatment region. In this configuration, the sensor may be delivered on a distal tip of a flexible probe that may or may not have treatment elements as well.

The goal of the treatment may be ablation, or necrosis of the target nerve or tissue, or some lesser degree of treatment to denervate the BVN. For example, the treatment energy or frequency may be just sufficient to stimulate the nerve to block the nerve from transmitting signal (e.g. signals indicating pain).

Once the treatment is complete, the probe <NUM> is withdrawn. The curved cannula <NUM> is then withdrawn into the needle trocar <NUM>. The needle trocar <NUM> with the curved cannula <NUM> is then removed and the access site is closed as prescribed by the physician.

In the above system <NUM>, the design of the curves <NUM> and <NUM> of the curved cannula <NUM> and curved stylet <NUM> is such that the flexible element (e.g. carrying the treatment device) can navigate through the angular range of deployment of the Nitinol tube of the curved cannula <NUM>. The curved nitinol tube <NUM> allows the flexible element to navigate through a curve within bone without veering off towards an unintended direction. Cancellous bone density varies from person to person. Therefore, creating a curved channel within varying density cancellous bone <NUM> will generally not predictably or accurately support and contain the treatment device as it tries to navigate the curved channel.

With the system <NUM> of the present invention, the treatment device <NUM> is deployed into the bone through the curved Nitinol tube of the curved cannula <NUM>, which supports the element as it traverses through the curve. When it departs from the tube, it will do so in a linear direction along path <NUM> towards the target zone. This allows the user to predictably and accurately deploy the treatment device towards the target zone T regardless of the density of the cancellous bone.

In some examples, a radius of curvature that is smaller than that which can be achieved with a large diameter Nitinol tube may be advantageous. To achieve this, the curved tube of the curved cannula <NUM> may take one of several forms. In one example, the tube <NUM> is formed from a rigid polymer that can be heat set in a particular curve. If the polymer was unable to hold the desired curve, an additional stylet (e.g. curved stylet <NUM>) of Nitinol, or other appropriate material, may also be used in conjunction with the polymer tube to achieve the desired curve. This proposed combination of material may encompass and number or variety of materials in multiple different diameters to achieve the desired curve. These combinations only need to ensure that the final outside element (e.g. trocar <NUM>) be "disengageable" from the internal elements and have an inner diameter sufficient to allow the desired treatment device <NUM> to pass to the treatment region T.

In an alternative example, of the curved cannula <NUM> may comprise a Nitinol tube having a pattern of reliefs or cuts (not shown) in the wall of the tube (particularly on the outer radius of the bend). The pattern of cuts or reliefs would allow the tube to bend into a radius tighter than a solid tube could without compromising the integrity of the tubing wall.

<FIG> illustrates example of the system or kit <NUM> that may be used to reduce the number of steps required for the procedure. This example includes a needle trocar <NUM>, straightening stylet <NUM>, used with the needle trocar <NUM> and the curved cannula <NUM> to create the initial path through the soft tissue and cortical shell to allow access to the cancellous bone, curved stylet <NUM> used in conjunction with the curved cannula <NUM> to create the curved path within the bone/tissue, and channeling stylet <NUM> used to create a working channel for the probe beyond the end of the curved path created by the curved stylet.

In one method (not claimed), the straightening stylet <NUM> is inserted into the curved cannula <NUM> and secured. The straightening stylet <NUM> has a sharp tip <NUM> designed to penetrate bone. Once the straightening stylet <NUM> is secure and the curved cannula <NUM> is straight, they are inserted into the needle trocar <NUM> and secured. The curved cannula <NUM> and straightening stylet <NUM> are inserted into the shaft <NUM> of the trocar <NUM> only as far as to have sharp tip <NUM> of the straightening stylet <NUM> protrude from the distal end <NUM> of the trocar <NUM>. Proper alignment is maintained by aligning a flat on the upper portion of the curved cannula <NUM> with a pin secured perpendicularly into the needle trocar <NUM> handle.

Referring now to <FIG>, once the curved cannula <NUM> is secure, the assembly (trocar <NUM>, curved cannula <NUM>, and straightening stylet <NUM>) is advanced through soft tissue to the surface of the bone. After finding the proper alignment at the pedicle <NUM> of vertebrae <NUM>, the assembly (trocar <NUM>, curved cannula <NUM>, and straightening stylet <NUM>) is advanced through the cortical shell <NUM> and into the cancellous interior <NUM> of the bone.

After the proper depth is achieved, the straightening stylet <NUM> is removed. The curved stylet <NUM> is then straightened out by sliding the small tube <NUM> on its shaft towards the distal tip <NUM>. The curved distal tip <NUM> is straightened out and fully retracted inside the small tube <NUM>, and then the curved stylet <NUM> is inserted into the curved cannula <NUM> which still resides inside the needle trocar <NUM>. Once the curved stylet <NUM> is inserted into the curved cannula <NUM>, the small tube <NUM> is met by a stop <NUM> (see <FIG>). As the curved stylet <NUM> continues to advance, the small tube <NUM> is held inside the handle of the curved cannula <NUM>. This allows the curve of the stylet <NUM> to be exposed inside the curved cannula <NUM>.

To create the maximum force, it is preferred that the curve of the two parts (<NUM> & <NUM>) are aligned. To ensure alignment the cap on the curved stylet <NUM> has an alignment pin, which engages with a notch on the top of the curved cannula <NUM>.

When the stylet <NUM> is fully seated and aligned with the curved cannula <NUM>, the tip of the curved stylet <NUM> will protrude from the tip of the curved cannula <NUM> by about <NUM>/<NUM> to <NUM>/<NUM> inches. This protrusion will help to drive the curved cannula <NUM> in the direction of its orientation during deployment. Once the curved stylet <NUM> and the curved cannula <NUM> are engaged, the lock nut at the top of the curved cannula <NUM> is rotated counter clockwise to allow the cannula <NUM> and stylet <NUM> to be advanced with relation to the needle trocar <NUM> (as shown in <FIG>). As the curved cannula and stylet are advanced they generate a curved path toward the treatment location T. Once the curved cannula <NUM> and stylet <NUM> are deployed to the intended angle, the lock nut at the top of the curved cannula <NUM> is engaged with the needle trocar <NUM> to stop any additional advancement of the curved stylet cannula assembly.

The curved stylet <NUM> is then removed and replaced by the channeling stylet <NUM>. The channeling stylet <NUM> is advanced beyond the end of the curved cannula <NUM> (see <FIG>) towards the intended target treatment zone creating a working channel for the active element to be inserted. Once the channeling stylet <NUM> reached the target treatment zone it is removed and replaced by the treatment device <NUM>, which is delivered to the treatment site T and activated.

Once the treatment is complete, the treatment device <NUM> is withdrawn. The curved cannula <NUM> is then withdrawn into the needle trocar <NUM>. The needle trocar <NUM> with the curved cannula <NUM> is then removed and the access site is closed as prescribed by the physician.

<FIG> illustrate detail views of a Nitinol wire for the curved stylet <NUM> (proximal end not shown). The wire comprises a shaft <NUM> having constant diameter D and a length Ls that may vary according to the application and desired depth to the treatment location. The wire has a preformed distal tip that is curved to have a radius r that redirects the distal tip <NUM> at an angle Θ with the shaft. As shown in <FIG>, angle Θ is shown to be approximately <NUM>°. However, it is appreciated that the preformed tip may have an angle ranging from a few degrees (slight deflection off axis), to up to <NUM>° (e.g. directing back toward the proximal end).

As shown in <FIG> detailing the distal tip <NUM>, the tip may have a distal extension LT that extends away from the shaft <NUM>. To promote channeling along a path that follows radius r, the distal tip <NUM> is configured with a dual-plane bevels <NUM> and <NUM>. Plane <NUM> is offset at angle β, and plane <NUM> is offset at angle α. This configuration of the leading- allows for the stylet and/or curved cannula to travel through bone in a path correlating to the specified curve in the stylet and/or cannula.

In the example illustrated in <FIG>, the curved stylet <NUM> has a shaft length Ls of approximately <NUM> in. , diameter D of approximately <NUM> in. , and a distal tip length LT of <NUM> (<NUM> inch), radius r of <NUM> (<NUM> inch), and angle β =<NUM>° and angle α= <NUM>°. It should be noted that the above dimensions are for illustration only, and may vary depending on the anatomy an tissue type.

It is appreciated that all the above examples may be provided as a kit of instruments to treat different regions of the body. For example, the location, orientation and angle of the treatment device with respect to the trocar <NUM> may be varied by providing a set of instruments at varying increments. This may be achieved by varying the curvature (<NUM>, <NUM>) in the curved cannula <NUM> and curved stylet <NUM>. The curvature may be varied by varying the radius of curvature r, the insertion depth (shaft length Ls and tip length LT, and/or the final exit angle Θ with respect to the trocar <NUM> central bore. Thus, the physician may select a different kit for treating a lumber spine segment as opposed to a cervical spine segment, as the anatomy will dictate the path that needs to be channeled.

Thus, when treating different spine segments, a set out of the kit may be selected to match the vertebra (or other region being treated). For example, delivering the treatment device at or near the BVN junction for a lumbar vertebra may have a different angle than for a cervical vertebra, and may vary from patient to patient. The set may be selected from the kit intraoperatively, or from a pre-surgery diagnostic evaluation (e.g. radiographic imaging of the target region).

It is appreciated that each of the instruments <NUM> and <NUM> detailed above may have any length, shape, or diameter desired or required to provide access to the treatment region (e.g. intraosseous nerve trunk) thereby facilitating effective treatment of the target region. For example, the size of the intraosseous nerve to be treated, the size of the passageway in the bone (e.g. pedicle <NUM>) for accessing the intraosseous nerve, and the location of the bone, and thus the intraosseous nerve, are factors that that may assist in determining the desired size and shape of the individual instruments.

The systems <NUM>, <NUM> described above may be used with a number of different treatment modalities for therapeutic treatment of the target region. For example, it is desirable to operate the treatment device <NUM> in a manner that ablates the tissue of the target region (e.g. BVN) to produce as described in <CIT>.

Claim 1:
A system (<NUM>) for navigating an instrument through bone and providing treatment within bone, the system (<NUM>) comprising:
a trocar (<NUM>) having a central channel and an opening at a distal tip (<NUM>) of the trocar (<NUM>);
a straight stylet (<NUM>) configured to be installed in the trocar (<NUM>), the straight stylet (<NUM>) comprising a sharp distal tip (<NUM>) that is configured to extend beyond the opening at the distal tip (<NUM>) of the trocar (<NUM>) and to pierce an outer cortical bone region of the bone;
a channeling instrument configured to be inserted through the trocar (<NUM>) after removal of the straight stylet (<NUM>) to create a predetermined-length linear path within a cancellous region of the bone toward a target treatment site (T); and
a treatment device (<NUM>) configured to provide a therapeutic treatment to the target treatment site (T).