Intraosseous nerve denervation device

Introsseous nerve denervation device

The present invention relates to a device for intraosseous nerve denervation.

In an effort to reduce low back pain through early intervention techniques, some researchers have focused on the nerves contained inside the vertebral bodies that are adjacent to the problematic disc. For example, WO-A-01/0157655 ("Heggeness") discloses the ablation of nerves contained inside the vertebral body by first piercing the vertebral body with a nerve ablation device, placing the tip of the device in the immediate vicinity of the nerve, and then performing the ablation of the nerves with the tip. The Heggeness document discloses the use of laser devices, electricity transmission devices, fluid transmission devices and thermal devices, and devices for carrying either chemotherapeutic or radioactive substances such as candidate nerve ablation devices.

In describing techniques that use electricity transmission devices, the Heggeness document discloses "raising the temperature of the tip 24 such that the intraosseous nerve is removed by the heat generated by the electrical current passing through tip".

The Heggeness document also discloses multiple procedures for accessing the intraosseous nerve (ION). However, each of these procedures essentially discloses or (i) drill a straight channel inside the vertebra so that placing an electrode tip near the end of that channel will bring the electrode tip quite close to the ION to perform its ablation, or ii) access the basivertebral nerve (BVN) through the vertebral foramen. None of these techniques identify how to effectively perform nerve ablation when the precise locations of the ION are unknown, or when the electrode tip cannot be maneuvered relatively close to the ION.

EP-A-1059067 ("Cosman") discloses an ablative treatment of metastatic bone tumors, including those found inside the spine. Pain relief is reportedly achieved by penetrating the bone wall with a suitable probe, and applying heat through the probe to remove

Either the bone tumor or the tissue near the bone tumor. The Cosman document teaches the use of both monopolar and bipolar probes in this application. Cosman's paper also teaches that treatment can also be used to remove nerves and nerve branches in and / or around the bone to desensitize them against an additional tumor invasion.

However, monopolar approaches require the use of a grounding panel below the patient and that allows energy to flow with respect to the probe and dissipate in the surrounding tissue. Because the path through which energy flows from a monopolar probe to its corresponding panel is not controlled, energy can flow undesirably through sensitive tissue, such as the spinal cord. Because this procedure can lead to local stimulation of muscle or unwanted nerve, it can be difficult or dangerous to operate in sensitive areas of the human body.

The Cosman document discloses devices whose electrodes can deviate from the axis of the access channel. In particular, the Cosman document discloses orientable tips, spring-type electrodes that take a straight shape inside the catheter and then bend after exiting the catheter. The Cosman document discloses that the curved part of the electrode may be a permanent rigid and robust curve, or it may be a flexible configuration such that it can be oriented, pushed or guided by the physician for placement in various locations. The Cosman document discloses that the electrodes may comprise a conduit made of an elastic or extremely elastic metal such as a nitinol or spring steel conduit such that the electrode can be inserted into straight segments of the cannula and still describes a curved path when the curved part emerges from the opening. The Cosman document also discloses an electrode that has a flexible but orientable tip that can define an arc, as configured by the doctor.

In sum, the Heggeness and Cosman documents disclose treatment procedures that assume that the electrode tip can be directed substantially towards the target tissue.

A few researchers have examined the effectiveness of bone heating with monopolar RF electrodes. DuPuy, AJR: 175, November 2000, 1263 to 1266 indicated a decreased heat transmission at a distance of 10 mm from the electrode through spongy bone in ex vivo studies. DuPuy indicates that local heat sinks from the rich epidural venous plexus and the pulsations of cerebrospinal fluid may explain the decreased heat transmission in the spongy bone. Tillotson, Investigative Radiology, 24:11, Nov. from 1989, 888 to 892, he studied percutaneous trigeminal ganglion ablation using RF energy, and determined that bone marrow necrosis was limited to a sphere of approximately 1 cm in diameter, regardless of the size of the probe and the duration of the heating. Tillotson also reports that Lindskog showed that heat transmission inside bone is clearly limited by blood flow, and that lethal temperatures cannot be maintained over long distances.

In sum, it seems that these researchers report that it seems that the well-vascularized nature of the bone limits the heating effect of RF electrodes at a distance of less than about 0.5 cm from the tip.

WO 96/36289 A discloses an endoscopic instrument that includes a hollow tube of small diameter, an axially removable wire extending through the tube, a manual actuator coupled to the proximal ends of the tube and the wire for axial displacement the wire in relation to the tube, a first end effector mechanically coupled to the distal end of the tube and having a proximal part that is provided with a curved guide channel, and a second end effector mechanically coupled to the distal end of the wire and rotatably coupled to the first end effector. When disposed as a bipolar instrument, the tube and traction wire are conductive, the end effectors are conductive and are partially covered with an insulating material. Both end effectors are preferably made of cast alloy coated with PTFE, and are rotatably coupled to each other with the help of an insulating ceramic bearing washer.

US-6312426 ("Goldberg") discloses an RF plate type electrode system to effect a large, uniform, and extended ablation of the tissue close to the plate type electrodes. In some embodiments, the plate-type electrodes are placed on the surface of the body tissue, in which the ablation is desired, and are configured to be arranged approximately parallel or towards each other, such that they produce a coagulating lesion. most of the body volume tissue between them. It seems that Goldberg's document is mainly focused on the treatment of tumors. Goldberg's paper states that an advantage of the system is that the surgeon does not need to determine the precise position of the tumor.

US-6139545 ("Utley") discloses a facial nerve ablation system that includes at least two bipolar probe electrodes separated from each other that encompass between them a region of percutaneous tissue that contains a branching of the facial nerve. Utley's paper teaches that the size and separation of the electrodes are set on purpose to penetrate the skin at a depth sufficient to encompass a nerve that is selected as a target or a nerve inside a defined region. The Utley document also teaches that the system makes possible the non-invasive selection of discrete motor nerve branches, which are small and interspersed in the muscle, making them difficult to see and detect, in order to select as a target specifically these for ablation. The Utley document does not disclose the use of such a system for the treatment of IONs, rigid probes, or deployable electrodes.

In attempting to place an electrode in the immediate vicinity of the BVN, the inventors of the present invention have determined that the approaches disclosed in the teachings of the art are somewhat problematic. In particular, although the location of the BVN is somewhat well known, the BVN is radiopermeable and thus its precise location cannot be easily identified by X-rays. Because the BVN is also extremely thin, deliberately placing the electrode in the immediate vicinity of the BVN can be problematic. In addition, because it seems that conventional RF electrodes heat only a rather limited bone volume, poor placement of the electrode tip with respect to the BVN can result in heating of a bone volume that does not contain the BVN.

For example, and referring to the drawings below, Figures 1 and 2 provide a representation of a treatment scheme that involves placing a conventional bipolar electrode device in the immediate vicinity of the ION. In these figures, the ION is represented by the continuous line that is identified as ION, while the dotted lines that are arranged vertically identify the edges of the area inside which the doctor thinks the ION is probably (that is, the ION presence zone, or "IRZ", ION presence zone). As shown in Figures 1 and 2, if the ION is substantially at the center of the ION presence zone, then the placement of the bipolar electrode or at the left limit of the ION presence zone (as in Figure 1) or substantially in the middle of the presence zone of the ION (as in Figure 2) successfully locates the electrodes in a region that allows the current flowing from the electrodes to flow through the ION. Because the current flowing through the ION can resistively and conductively heat the local bone tissue and the ION will be heated to therapeutically beneficial temperatures, these cases can provide a beneficial treatment of the ION.

However, and referring to Figure 3 below, if the ION is substantially on the right edge of the ION presence zone, then the placement of the bipolar electrodes on the left side of the ION presence zone is unable to locate the electrodes in a region that allows the current flowing from the electrodes to flow through the ION. Therefore, the current flowing through the electrodes cannot resist the ION resistively. In addition, because the bone is a heat sink that effectively limits heat transport to approximately 0.5 cm, the heat produced by the electrodes can dissipate effectively before it can reach the ION by conduction.

Similarly, and referring to Figure 4 below, if the ION is substantially on the left edge of the ION presence zone, then the placement of the bipolar electrodes in the middle of the ION presence zone is unable to locate the electrodes in a region that allows the current flowing from the electrodes to flow through the ION. Again, the current flowing through the electrodes cannot resist the ION resistively, and the heat sink quality of the bone can effectively dissipate the heat produced by the electrodes before it can reach the ION by driving.

Furthermore, even if the precise location of the BVN was known, it has been determined that it is difficult to access the back of the BVN from a transpedicular approach with a substantially straight probe.

Therefore, the present invention seeks to provide a system that allows the physician to heat the BVN without having to know the precise location of the BVN, and without having to precisely position the electrode tip near the part of the BVN that is going to be treated

The present invention relates to the production of a large but well controlled heating zone inside the bone tissue to therapeutically treat an ION inside the heating zone.

Referring now to Figures 5 and 6, a representation of an embodiment of the present invention is provided in which probes arranged respectively of electrodes E1 and E2 (not shown) treat the ION therapeutically. Figure 5 provides a schematic representation of the electric field EF that is produced in bone tissue by activation of the electrodes. In this case, the electric field is relatively thin. Figure 6 provides a schematic representation of the total heating zone THZ (total heating zone) produced by the electric field of Figure 5 including both an IR internal resistive heating zone (represented by an open circle) and a zone of OC outer conductor heating (represented by closed circles). In this case, the inner resistive zone is produced by the Joule heating of the bone tissue disposed inside the EF electric field, while the outer conductor zone is heated by heat conduction from the resistive heating zone.

Referring still to Figure 6, the inventors of the present invention have determined that by placing the active and return electrodes of an energy transmission device in a way that allows the electrodes to extend to both sides of the presence zone of the ION IRZ provides a large but well controlled total heating (IR + OC) zone inside the bone tissue to therapeutically treat the ION inside the heating zone. Because the total heating zone is large and the electrodes extend to both sides of the IRZ, there is a high level of confidence that a part of the ION will be present inside the total heating zone. Because the total heating zone is well controlled, there is no danger (as with monopolar systems) that the current flowing from the active electrode undesirably affects collateral tissue structures

Referring now to Figure 7, if the ION is in fact substantially at the center of the presence zone of the ION, then the placement of the bipolar electrodes in a way that extends to both sides of the presence zone of the ION allows the production of a zone of total heating between the electrodes that includes a part of the ION inside.

In addition, the present invention allows the physician to treat the ION therapeutically even when the ION is in fact at the edges of the zone of presence of the IRZ ION. Referring below to Figures 8 and 9, if the ION is substantially on the right edge (as in Figure 8) or on the left edge (as in Figure 9) of the IRZ ION presence zone, then The placement of bipolar electrodes in a way that extends to both sides of the ION presence zone still allows the production of a total heating zone between the electrodes that includes a part of the actual ION inside.

Therefore, the extension on both sides of the ION presence zone by the present invention successfully locates the electrodes such that the total heating zone produced by electrode activation includes the ION regardless of the actual location. of the ION inside the zone of presence of the ION IRZ, thus guaranteeing that the electrodes will always heat the ION at therapeutically beneficial temperatures.

In accordance with the present invention there is provided a device for the denervation of an intraosseous ION nerve in a bone, comprising:

a fixed probe comprising a tree having a longitudinal axis, a distal end part, a proximal end part and a longitudinal interior surface extending from the proximal end part; and a pivoting probe comprising a shaft having a longitudinal axis, a distal end part and a proximal end part, in which the distal end part is coupled so that it can pivot to the fixed probe; in which the pivoting probe shaft contains first and second electrodes for electrical connection with a power supply; and wherein the fixed probe comprises a recess that forms a lateral opening in the shaft of the fixed probe to accommodate the pivoting probe.

The device can be used in a procedure to therapeutically treat a bone that has an IOS intraosseous nerve that defines first and second sides of the bone, comprising the steps of:

insert an energy device that has an active electrode and a return electrode inside the bone, place the active electrode on the first side of the bone and the return electrode on the second side of the bone to define a total heating zone between the themselves, and apply a voltage of a frequency high enough between the active and return electrodes to generate a current between them to resistively resist the total heating zone sufficiently to denervate the ION.

In addition, the present invention provides a very controlled total heating zone that exists substantially only between the pair of electrodes. The ability of the present invention both to heat the BVN therapeutically with substantial certainty and to minimize the volume of bone tissue affected by heating appears to be novel in light of conventional bone-related technology.

Therefore, the present invention is additionally advantageous because it allows the physician to create a heating zone large enough to therapeutically treat the ION without requiring direct access to the ION.

Therefore, in the preferred embodiments, the present invention is advantageous because it does not require knowing the precise location of the ION, does not require direct access to the ION, and its controlled heating profile allows the physician to avoid heating the adjacent structures. such as healthy adjacent spongy bone tissue, spinal cord or opposite vertebral endplates.

The system of the invention can be used in a method for therapeutically treating a vertebral body having a BVN that defines first and second sides of the vertebral body, comprising the steps of:

<dl><dt>(to)</dt><dd> determine a zone of presence of BVN inside which the BVN is probably located, the zone of presence of BVN having a first side and a second side, </dd></dl>

<dl><dt>(b) </dt><dd>insert an energy device that has an active electrode and a return electrode inside the vertebral body, </dd></dl>

<dl><dt>(c) </dt><dd>place the active electrode on the first side of the presence zone and the return electrode on the second side of the presence zone to define a total heating zone between them, and </dd></dl>

<dl><dt>(d)</dt><dd> apply a voltage of a frequency high enough between the active and return electrodes to generate a current between them to resistively resist the total heating zone to a temperature sufficient to denervate the BVN. </dd></dl>

The invention is described with reference to the accompanying drawings, in which:

Figures 1 and 2 represent the treatment of BVN with a conventional bipolar electrode. Figures 3 and 4 represent the difficulty of treating a BVN with a conventional bipolar electrode. Figures 5 and 6 respectively represent views from above of an electric field and of a zone of total heating that is produced inside the bone tissue by an embodiment of the present invention. Figures 7 to 9 represent the treatment of BVN with a bipolar electrode apparatus of the present invention. Figures 10a and 10b disclose views in front and top cross-section of an extended ION that extends in a plane above the electrodes but inside the total heating zone. Figure 11 is a cross-sectional front view of an embodiment of the present invention in which the total heating zone has resistive heating zones of the bicircular type. Figure 12 depicts a top view of the treatment of BVN with a bipolar electrode apparatus of the present invention in which the distal ends of the probes are substantially in the midline of the vertebral body. Figure 13 discloses cross sections of components of a double probe apparatus which is not according to the present invention. Figure 14 discloses another apparatus that is not according to the present invention in which a part of the probe shaft acts as an electrode. Figures 15 to 18 disclose four arrangements in which at least a portion of the electrode faces thereof are arranged in a substantially parallel relationship. Figure 19 discloses a cross-sectional view of an apparatus that is also not according to the present invention, in which the cannula has an inner surface having a distal curve and a lateral opening. Figures 20a and 20b disclose cross-sectional views of an additional apparatus other than according to the present invention, in which the cannula has a proximal curve.

Figures 21a and 21b disclose cross-sectional views of an apparatus that is not according to the present invention, in which the probe has a rotated part containing an electrode. Figure 22 discloses a probe having inverse conical electrodes. Figure 23 discloses a probe that has a plurality of active electrodes and a plurality corresponding return electrodes. Figure 24 discloses a bipolar probe in which the return electrode has a surface area relatively large Figure 25 shows a cross-sectional view of an articulated probe having electrodes both active and return. Figure 26 discloses the treatment of a posterior part of the BVN with a bipolar electrode apparatus. Figures 27 a – d show views from above, anterior, lateral and in perspective with respect to the placement of a bipolar electrode device inside a vertebral body. Figures 28 a and 28b show the location of thermocouples T0 to T14 inside the body vertebral Figures 29 a – c show the temperatures recorded by thermocouples T0 to T14. Figures 30 a – b show the peak temperatures recorded by thermocouples T0 to T14 in the inside the vertebral body. Figures 31 a – e show top views of a preferred use of the articulated probe of the figure 25. Figure 32 shows an embodiment of a double articulated needle of the present invention.

For the purposes of the present invention, the "resistive heating zone" is the area of ​​bone tissue that is resistively heated due to a loss of energy in which the current flowing directly through the bone tissue incurs. Resistive heating, "Joule" effect heating and "near field" heating can be used interchangeably herein. The "conductive heating zone" is the area of ​​bone tissue that is heated due to heat conduction from an adjacent resistive heating zone. The THZ total heating zone in a bone tissue includes both the resistive heating zone and the conductive heating zone. The boundary between the conductor and the resistive heating zones is defined by the locations where the intensity of the electric field is 10% of the maximum intensity of the electric field between the electrodes. For the purposes of the present invention, the heating zones encompass the volume of bone tissue heated to at least 42 ° C by the present invention. For the purposes of the present invention, the "first and second sides" of a vertebral body are the lateral-lateral sides to which the BVN intersects.

The therapeutic treatment of the ION can be carried out in accordance with the present invention by resistive heating, conductor heating, or by hybrid heating.

In some embodiments, therapeutic heating of the ION is provided by both resistive and conductive heating. In some embodiments thereof, as in Figure 6, the electrodes are positioned such that the ION passes through the IR resistive heating zone, such that the length L1 of the ION is heated therapeutically by bone tissue. in the zone of resistive heating IR and the lengths L2 and L3 of the ION are heated therapeutically by the bone tissue in the zone of conductive heating OC.

In embodiments in which the therapeutic heating of the ION is provided substantially by both resistive and conductive heating, it is preferred that the length L1 of the ION treated by resistive heating comprises at least 25% of the total therapeutically treated length of ION, more preferably at least 50%. In many embodiments, the peak temperature in the IR resistive heating zone is between 40 ° C and 60 ° C higher than the peak temperature in the conductive OC heating zone. Preferably, the peak temperature in the IR resistive heating zone is no more than 15 ° C higher than the peak temperature in the conductive heating zone OC, more preferably no more than 10 ° C, more preferably no more than 5 degrees.

Referring now to Figures 10a and 10b, in some embodiments, the therapeutic heating of the ION is essentially provided by the conductive heating zone OC. This may take place when the ION is in fact substantially away from the middle of the presence zone of the IRZ ION. In such a case, the electrodes are placed in such a way that the ION passes only through the conductive heating zone, such that the length L2 of the ION is heated therapeutically by means of bone tissue in the conductive heating zone. OC.

In preferred embodiments thereof, it is desired that the separation distance SD between the ION and the resistive heating zone IR be no more than 1 cm. This is desired because the closer the ION is to the resistive heating zone, the higher the temperature experienced by the length of ION L2 will be. More preferably, the separation distance is no more than 0.5 cm, more preferably no more than 0.2 cm.

In some embodiments, as in Figure 10, the electric field is strong enough to be substantially continuously between the two electrodes. This usually takes place when the electrodes are very close to each other (that is, no more than 5 mm apart). In others, however, as in Figure 11, the electric field is relatively weak and thus is substantially only in the vicinity of the two electrodes. In such cases, and referring to Figure 11 below, the inward flow of energy from the resistive IR heating zones conductively heats the intermediate area of ​​the OCI conductive heating zone. Preferably, the peak temperature in the IR resistive heating zone is no more than 15 ° C higher than the peak temperature in the intermediate conductive heating zone OC1, more preferably no more than 10 ° C, more preferably no more of 5 ° C.

In preferred embodiments, the present invention is carried out through a double probe system. In particular, the present invention preferably comprises an energy delivery device comprising a first probe having an active electrode and a second probe having a return electrode. Referring next to Figure 12, this double probe embodiment allows the surgeon to approach the BVN from separate sides of the vertebral body to easily extend to both sides of the IRZ with the electrodes. With such a device, the surgeon can place the first probe 601 that has an active electrode 603 on a first side of the vertebral body and the second probe 611 that has a return electrode 613 on a second side of the vertebral body, and then align the pair of electrodes so that their activation produces a zone of total heating that extends to both sides of the IRZ and therefore the BVN inside.

Because the alignment of the electrodes of such an apparatus to extend on both sides of the ION merely requires progressing the probes into the vertebral body, complicated navigation is not required. The inventors of the present invention have appreciated that, even if the location of the BVN is known precisely, conventional procedures for accessing the BVN require either i) that the BVN be found naturally inside the vertebral body in order to to intersect the axis of the pedicle (Heggeness document), or require a complicated probe or navigation configuration (such as those described in the Cosman document). Because the double probe approach simply requires a substantially linear advance of a pair of substantially straight probes, it is much simpler and / or much more robust than conventional procedures for accessing bone nerves. In fact, with this embodiment of the present invention, the physician can then desirably access the vertebral body through the pedicles with substantially straight probes and have a high confidence that their activation can therapeutically treat BVN.

The system of the invention can therefore be used in a method of therapeutically treating a vertebral body having a BVN, comprising the steps of:

provide an energy device that has an active electrode that has a first face and a return electrode that has a second face inside the vertebral body, and place the active electrode on the vertebral body to face a first direction, place the return electrode in the vertebral body to face a second direction, the first and second faces defining an angle 25 of no more than 60 °, and apply a voltage difference of a frequency high enough between the active and return electrodes to generate a current between them to produce a total heating zone to therapeutically heat the BVN.

The system of the invention can therefore be used in a method of therapeutically treating a vertebral body having a BVN, comprising the steps of:

provide an energy device having an active electrode and a return electrode, place the active and return electrodes on the vertebral body to define an electrode axis, the axis forming an angle between 50 and 90 ° with the BVN, and apply a voltage difference of a frequency high enough between the active and return electrodes to generate a current between them to produce a total heating zone to therapeutically heat the BVN.

Referring now to Figure 13, a double probe apparatus is provided comprising first 101 and a second 151 cannulas, a first 201 and a second 251 stilettos, a first 301 and a second 351 probes, and a power supply 401 in electrical connection with the probes. For simplicity, only a single cannula, stylet and probe will be described further. However, the expert will appreciate that the preferred arrangements use two sets of such devices.

Referring now to Figure 13, the cannula 101 comprises a shaft 103 having a longitudinal interior surface 105 through which it defines an internal diameter DC. The distal opening 109 of the cannula provides a working inlet for the probe. This is further sized to allow the distal end of the probe to progress beyond the distal end 107 of the cannula. The length Lc of the cannula is sized to reach from the patient's skin a location inside the spongy bone region of the target bone. Preferably, the cannula is made of a material selected from the group consisting of metal and polymer, and is preferably polymer. In many embodiments, the cannula is made of an insulating material in order to prevent a leakage current with respect to the probe from coming into contact with a tissue that is not selected as the target.

The cannula can be shaped in order to guide the probe toward the midline of the vertebral body. This inward guidance will help move the electrodes closer to the BVN. At least a part of the inner surface of the cannula is curved. At least half of the length of the inner surface of the cannula can be curved. Alternatively, substantially only the distal end portion of the inner surface of the cannula can be curved.

The stylet 201 comprises a tree 203 having a longitudinal axis A and a proximal end 205 and a distal end 207. Arranged at the distal end of the tree is a tip 209 adapted to pierce or drill through cortical bone. The outer diameter OD of the stiletto shaft is preferably adapted to be housed inside the inner diameter DC of the cannula.

The combination of the cannula and the stylet is referred to as a "needle with cannula". Access to the vertebral body can be achieved by first placing the stylet in the cannula to produce a needle with cannula, piercing the skin with the needle with cannula, and progressing the needle with cannula so that the stylet tip reaches a region of target tissue inside the spongy part of the vertebral body, and then removing the stylet. At this point, the cannula is conveniently in the region of target tissue to receive a probe.

The probe 301 comprises a shaft 303 having a longitudinal axis B, a distal end portion 305 and a proximal end portion 307. The first electrode 309, which has a first face 331 and a connection face 333, is disposed near the distal end part of the probe. The probe is designed in such a way that the connection face of the first electrode is placed in electrical connection with a first conductor 403 of the power supply. The shaft has a longitudinal interior surface 311 that extends from the proximal end portion to at least the first electrode. A wire 321 electrically connected at its first end 323 to the first electrode and having a second end 325 adapted to be electrically connected to a first conductor of a power supply is disposed within the interior surface.

Therefore, an intraosseous nerve denervation system is provided, comprising:

a cannula having a longitudinal interior surface, a stylet that has an outer diameter adapted to stay inside the inner surface longitudinal and a distal tip adapted to penetrate the cortical bone, and a first probe comprising:

an outer diameter adapted to be housed inside the longitudinal inner surface, and a first electrode, and a conductor in electrical connection with the first electrode.

The outer surface of the probe can be provided with depth marks in such a way that the doctor can capture the extent to which it has penetrated the vertebral body.

In some arrangements where a stylet with a cannula is inserted first, the stylet is removed and the cannula remains in place with its distal opening residing in the target tissue while the probe is inserted inside the cannula. In this arrangement, the cannula provides a secure entry for the probe, thereby ensuring that the probe can be inserted into the bone safely. This arrangement is especially preferred when the probe is made of a flexible material, or is formed with an irregular cross-section that can be attached to the bone undesirably during the advance of the probe inside the bone.

In the probe of Figure 13 which is disclosed above, the probe 301 has a blunt tip. Alternatively, the probe carrying an electrode may be configured to have a sharp distal tip that is sharp enough to penetrate the cortical bone. With such a tip, the doctor can eliminate stages in the procedure that are related to either the stylet or the stylet with cannula, and save time in this way.

Referring now to Figure 14, the electrode may include a part of the probe tree. For example, in the case of probe 1401, the probe comprises: an electrically conductive inner shaft 1403 in electrical connection with a power source 1409, and

an insulating outer jacket 1405 that is wound around a part of the tree.

In this configuration, the placement of the jacket provides an uninsulated distal shaft portion 1407 that can be used as an electrode. Preferably, the non-isolated distal part of the tree is between 3 mm and 8 mm in length, and is more preferably about 5 mm. In preferred embodiments thereof, the insulation is selected from the group consisting of polyimide tape, PTFE tape, and heat shrink tubing. The preferred thickness of the insulation varies between about 6.35 and about 12.7 µm (from 0.00025 to 0.0005 inches).

In other arrangements that use insulating sleeves, the jacket has either a groove or a longitudinally extending notch that exposes a longitudinal surface area of ​​the underlying tree, thereby producing either an essentially linear electrode or an essentially flat electrode. In such arrangements, the distal end of the tree may preferably be isolated. In other arrangements using insulating sleeves, the insulated portion may comprise a proximal sleeve and a distal sleeve that are positioned to provide a space therebetween that exposes a surface area of ​​the underlying tree to produce the electrode. In some arrangements, the proximal and the distal jacket substantially surround the tree to provide an annular electrode therebetween.

In some arrangements where a stylet with a cannula is used, both the stylet and the cannula are removed, and the probe is inserted into the hole created by the stylet with cannula. In this arrangement, the hole provides a large input for the probe. This arrangement retains the bone crown removed by the cannula, and thus is preferred when the probe has a relatively large diameter (for example, more than 8 mm in diameter).

In some arrangements in which a stylet with a cannula is used, the cannula comprises at least one electrode. In this arrangement, the cannula also acts as a probe. With this arrangement, the doctor can eliminate stages in the procedure that are related to the introduction of a body inside the cannula. In some arrangements, the outer surface of the cannula is provided with depth marks in such a way that the doctor can capture the extent to which the cannula has penetrated the vertebral body.

In some arrangements in which a stylet with a cannula is inserted first, the stylet comprises at least one electrode. In this arrangement, the stylet also acts as a probe. With this arrangement, the doctor can eliminate stages in the procedure that are related to the removal of the stylet and the introduction of a body inside the cannula. In some arrangements, the outer surface of the stylet is endowed with depth marks such that the doctor can capture the extent to which it has penetrated the vertebral body.

In conducting experiments with initial animals with a double probe device, the inventors of the present invention used a bipedicule approach as shown in Figure 12, such that each probe approached the ION at an angle 5 of 45 to approximately 55º. Because both the probes and the electrodes disposed thereon were essentially cylindrical, the inner faces 605, 615 of the electrodes produced an angle 25. Further tests of the configuration of Fig. 12 revealed somewhat higher temperatures at the distal part of the electrodes and somewhat lower temperatures near the proximal parts of the electrodes. Without the intention of sticking to a theory, it is believed that the shortest path between the distal regions produced a lower resistance region (compared to more proximal regions between electrodes) and thus resulted in the current following in a way the path of least resistance between the distal parts is preferred. Accordingly, the inventors of the present invention sought improvement against the relatively uneven temperature profile produced by the electrode design of Figure 12.

The inventors of the present invention modified the electrode design to reduce the angle 25 produced by the inner faces, such that the distance between the proximal end of the electrodes is more equal to the distance between the proximal end of the electrodes (it is say, the faces are more parallel). When the electrodes are provided in such a condition, their orientation reduces the importance of any path of least resistance, and thus the current flows more evenly through the face of each electrode, thereby providing uniform heating and Greater control over the system.

Therefore, an intraosseous nerve denervation device is provided, comprising:

a first probe that has an active electrode and a first conductor, a second probe that has a return electrode and a second conductor, means for creating first and second interior surfaces inside a bone to house the first and second probes, a power supply capable of generating a voltage difference between the active electrodes and of return, the source having third and fourth drivers, in which the first and third conductors are in electrical connection, and the second conductors and fourth are in electrical connection.

Preferably, the electrodes are arranged such that the angle 25 produced by the inner faces is less than 60 °, more preferably not more than 30 °. Even more preferably, the angle is less than 1 °. Most preferably, the inner faces are substantially parallel.

Referring now to Figure 15, in some device arrangements, substantially parallel electrodes are provided using conical electrodes 501 whose section decreases distally. In this figure 15, each cone electrode 501 has a distal end 503 having a diameter DD and a proximal end 505 having a diameter DP, in which the diameter of the distal end DD is larger than the diameter of the proximal end DP . Preferably, the angle and the decrease in cone section is substantially equal to angle 5. In this condition, the inner faces of the conical electrodes will be essentially parallel to each other.

Therefore, an intraosseous nerve denervation system is provided comprising:

a first probe having a first electrode and a first conductor in electrical connection with the first electrode, in which the first electrode has a proximal end having a proximal diameter and a distal end having a distal diameter, and the diameter of the end proximal is smaller than the diameter of the distal end, and a second probe having a second electrode and a second conductor in electrical connection with the first electrode, in which the second electrode has a proximal end having a proximal diameter and a distal end having a distal diameter, and the diameter of the proximal end is smaller than the diameter of the distal end, and in which the first and second electrodes are they have such that the electrodes are parallel.

In Figure 10, the conical shapes are frustoconic (that is, they are parts of a cone). Frustoconic electrodes are desirable in situations where tissue carbonization needs to be avoided, because the relatively large diameter of the distal end of the electrode cannot provide a path for high current density (in relation to the proximal end of the electrode). Frustoconic electrodes are also desirable in situations where the probes are arranged at a relatively high angle 5, in which the use of sharp tip electrodes would substantially shorten the distance between the distal electrode tips and thus create a path. Undesirable of significantly less resistance.

In some arrangements, the frustoconic electrode is shaped such that the diameter of its distal end DD is between about 10% and 25% of the diameter of its proximal end DP. In some arrangements, the frustoconic nature of the electrode is provided by physically sectioning the sharp distal end of the electrode. In others, the frustoconic nature of the electrode is provided by isolating the sharp distal end of an electrode.

As indicated above, when the probes are positioned such that their corresponding electrodes are parallel to each other, the electric field produced by electrode activation is substantially uniform between the distal and proximal parts of the electrodes. However, as the probes are oriented at an angle with respect to being in parallel, the electric field becomes more intense where the electrodes are closer to each other. In order to compensate for this non-uniform electric field, the cross section of the distal ends of the electrodes can be diminished. In this state of diminished cross-section, the regions of the electrodes that are closest to each other (for example, the tip) also have a smaller surface area (thereby reducing the electric field in that region), while the regions of the electrodes that are further apart (for example, the trunk) have a larger surface area (thereby increasing the electric field in that region). Usually, the effect is largely determined by cone size, electrode separation and the type of tissue between them.

In some preferred arrangements of the electrode of reduced cross-section, and referring next to Figure 16, the distal end of the electrode ends at a sharp point, such that the electrode has a more completely conical shape. Preferably, the conical electrode is shaped such that the diameter of its distal end is no more than 20% of the diameter of its proximal end, more preferably no more than 10%, more preferably no more than 1 %. In addition to compensate for the lack of uniformity in the electric field, the sharp point may also be adapted to penetrate the cortical layer of the vertebral body.

Referring now to Figure 17, in some arrangements, the current flows through an electrode having only a part of the conical or frustoconic shape. When electrodes of this type, which are called "sectorized cones", are oriented towards each other, their use is advantageous because they guarantee that the current will flow for the shortest distance, and thus provide efficiency. Sectorized cones can be produced by first manufacturing flat electrodes 511 and placing the flat electrode on a probe surface at a convenient angle 513. Alternatively, these can be produced by first manufacturing the conical electrode configuration of Figure 15, and masking then a part of the conical electrode with an insulating material. Unlike the arrangement of Figure 15, this sectorized cone embodiment requires careful alignment of the electrode faces and may require in vivo rotation of the electrodes to achieve the desired alignment.

Referring now to Figure 18, in other arrangements, substantially parallel electrodes can be provided using elbow-shaped probes 531. The elbow-shaped probes have a distal end 533 and a proximal end 535 that are located at an elbow 537. In some arrangements, the elbow can be produced during the manufacturing process (thus requiring a smaller diameter probe in order to fit through the cannula). In other arrangements, the elbow is produced in vivo, such as through the use of a tensile wire, a pivot or a memory effect metal disposed inside the probe.

Referring now to FIG. 19, in some arrangements, the first 551 and second 552 cannulas are each provided with a curved inner surface 553, 554 forming lateral distal openings 563, 564 at their distal end portions 555, 556 respective. When flexible probes 557, 558 containing an electrode 559, 560 are passed through the curved inner surface, the distal end 561, 562 of the probe fits similarly to the curved inner surface, thereby forming a internal angle to the probe £ determined by the proximal AP and distal AD axes of the probe. Preferably, this internal angle to the probe is between 90 and 135 degrees. Preferably, the internal angle to the probe is selected such that the distal axes AD of the probes leaving the cannulas form an angle of no more than 30 degrees, preferably not more than 10 degrees, more preferably form a substantially relationship parallel.

Therefore, an intraosseous nerve denervation system is provided, comprising:

a cannula having a longitudinal inside surface defining a first axis, a stylet having an outside diameter adapted to be housed inside the longitudinal inside surface and a distal tip adapted to penetrate the cortical bone, and a first probe having a outer diameter adapted to be housed inside the longitudinal inner surface, and a first electrode, and a conductor in electrical connection with the first electrode.

Referring now to Figures 20a and 20b, in some arrangements, first 701 and second 751 cannulas are each provided with a curved inner surface 703, 753 in their respective distal portions 705, 755, in which each inner surface has a proximal lateral opening 707, 757. The apparatus additionally comprises first and second probes 711, 761, each containing an electrode 713, 763. In some arrangements, the probe may settle in a distal region of the inner surface (as in Figure 20a) during the advancement of the cannula. Once the target tissue region is reached, then the probes are displaced proximally (by, for example, a tensile wire - not shown) and exit the proximal lateral openings such that the inner faces 715, 765 of the electrodes are oriented towards each other.

Therefore, an intraosseous nerve denervation system is provided, comprising:

a cannula having a longitudinal inside surface defining a first axis, a stylet having an outside diameter adapted to be housed inside the longitudinal inside surface and a distal tip adapted to penetrate the cortical bone, and a first probe having a outer diameter adapted to be housed inside the longitudinal inner surface, and a first electrode, and a conductor in electrical connection with the first electrode.

Referring now to Figure 21a and 21b, in some arrangements, at least one probe 801 comprises i) a distal part 803 having an electrode 805 and ii) a proximal part 807, the distal part being pivotally coupled to the proximal part by pivot 809. In some arrangements, two probes having such electrodes pivotally coupled are introduced through the cannulas in a first linear mode (shown in Figure 21a) to produce an angle 8 between the electrodes. Next, the respective pivots are actuated (by, for example, a tensile wire - not shown) to produce the angle configuration shown in Figure 21b that reduces the angle 8 between the electrodes. Preferably, the pivot places the electrodes in a substantially parallel relationship.

Therefore, an intraosseous nerve denervation system is provided comprising a first probe having a distal part having a first electrode, a proximal part comprising a first conductor in electrical connection with the first electrode, and a pivot connecting pivotally the proximal and distal parts of the probe.

In some arrangements, relatively uniform heating is provided by providing current density gradients. Referring now to Figure 22, in some arrangements, first 821 and second 831 probes have first 823 and second 833 electrodes having an inverted cone shape. In particular, each electrode has a relatively thick distal part 827, 837 and a relatively thin proximal part 825, 835. When this probe is activated, it is believed that the current density of this electrode will vary axially, with a relatively high current density present in the proximal part of each electrode (due to the smaller surface area) and a relatively low current density present in the distal part of the electrode (due to the greater surface area). This gradient of current density has to provide a more uniform heating zone when the electrodes are oriented by themselves at a significant angle, due to the preference for tip heating (which gives rise to the angle orientation of the electrodes ) is substantially balanced by the highest current density in the proximal parts of the electrodes.

Therefore, an intraosseous nerve denervation system is provided comprising a first probe having a first electrode and a first conductor in electrical connection with the first electrode, in which the first electrode has a proximal end having a proximal diameter and a distal end having a distal diameter, and in which the diameter of the proximal end is smaller than the diameter of the distal end.

Current density gradients can also be produced by providing a plurality of electrodes on each probe. Referring now to Figure 23, in some arrangements, the first and second electrodes each have a plurality of electrodes. In particular, the first probe 851 has first 853, second 854 and third 855 active electrodes, while the second probe 861 has first 863, second 864 and third 865 return electrodes. The voltage across the probes can be selected such that there is a rising voltage (and therefore a current) through the more widely separated electrodes (i.e., V855–865 &lt;V854–864 &lt;V853–863) . In some arrangements, the probes of Figure 23 are driven by multiple voltage sources (ie, a first voltage source to provide a voltage between the first active electrode 853 and the first return electrode 863, etc.).

The system can therefore be used in a procedure to therapeutically treat a vertebral body that has a BVN, comprising the steps of:

provide a first energy device that has distal and proximal active electrodes, provide a second energy device that has distal and proximal return electrodes, place the first and second energy devices in the vertebral body to define a first distance between the distal active electrode and distal return electrode, and a second distance between the proximal active electrode and the proximal return electrode, in which the first distance is less than the second distance, apply a first high frequency voltage between the active distal and distal return electrodes, and apply a second high frequency voltage between the proximal active and proximal return electrodes, in the that the first high frequency voltage is less than the second high frequency voltage.

Because multiple voltage sources can add complexity to the device, in other arrangements, differences in voltage can be predicted by a single voltage source using a poorly conductive electrode. In particular, in some arrangements thereof, the probe comprises an electrically conductive probe shaft and a plurality of insulating sleeves separated from one another in which the separation produces the electrodes of the figure.

2. 3. In this jacketed arrangement, the probe shaft can be made of a material that is a relatively bad electrical conductor (such as the tantalum) such that, when a single driving force is applied between the jacketed probes, the voltage is the highest in the proximal electrode 853, but the loss due to the bad conductance produces a substantially lower voltage in the distal electrode 855. This jacketed arrangement eliminates the need for multiple voltage sources.

In another double probe approach, in some arrangements, and referring next to Figure 24, an apparatus is provided having a first probe 871 having an active electrode 873, and a second probe 881 having a return electrode 883 , wherein the ratio of the surface area of ​​the active electrode to the surface area of ​​the return electrode is very high, that is, at least 2: 1 (more preferably at least 5: 1). In this condition, the current density will be very high in the active electrode and very low in the return electrode, so that the total heating zone THZ will take place essentially only around the active electrode. Because this device is essentially heated only at the active electrode, this device substantially mimics the heating profile of a monopolar electrode, although it provides the desirable safety feature of locally directing the current towards the return electrode.

Therefore, an intraosseous nerve denervation system is provided comprising:

a first probe that has an active electrode that has a first surface area, and a first conductor in electrical connection with the first electrode, a second probe that has a return electrode that has a second surface area, and a second conductor in electrical connection with the second electrode, in which the first surface area is at least twice as large as the second surface area, and means for creating a first and second interior surfaces inside a bone to accommodate the first and second probes.

Although the double probe approach has many benefits, in other embodiments of the present invention, an articulated probe having both active and return electrodes can be used in accordance with the present invention.

Referring now to Figure 25, an articulated device is provided. This device 900 comprises a fixed probe 901 and a probe that can pivot 951.

The fixed probe 901 comprises a shaft 903 having a longitudinal axis and a distal end portion 905 comprising a sharp distal tip 906 and a proximal end portion 907. The first electrode 909 is disposed near the distal end portion of the probe. The fixed probe is designed in such a way that the first electrode is placed in electrical connection with a first conductor of a power supply. In this particular embodiment, the shaft has a longitudinal interior surface 911 that extends from the proximal end portion to at least the first electrode. Inside the inner surface there is a first wire (not shown) electrically connected at its first end to the first electrode and having a second end adapted to electrically connect to a first conductor of a power source (which is not sample). The fixed probe also comprises a recess 927 that forms a lateral opening in the shaft and is designed to accommodate the probe that can pivot when it is in its unfolded mode.

The pivoting probe 951 comprises a shaft 933 having a longitudinal axis, a proximal end portion 955, and a distal end portion 957 pivotally coupled to the probe fixed by pivot 961. The pivot allows the pivoting probe pivot around the fixed probe. The second electrode 963 is disposed near the proximal end portion of the pivoting probe. The probe is designed in such a way that the second electrode is placed in electrical connection with a second conductor of the power supply.

The pivoting probe has an unfolded mode and an unfolded mode. In the non-deployed mode, the pivoting probe sits inside the recess of the fixed probe so that the axis of its shaft is essentially in line with the axis of the shaft of the fixed probe. In this state, the pivoting probe essentially hides inside the fixed probe. In the unfolded mode, the pivoting probe extends at a significant angle with respect to the fixed probe so that the axis of its tree forms an angle of at least 10 ° with the axis of the fixed probe tree.

In some embodiments, a push rod is used to deploy the pivoting probe. Push rod 975 comprises a proximal handle (not shown) for clamping and a distal end portion 977 that has a shape to access the inner surface of the fixed probe. The distal end portion has a tip 981 that has a shape that, when progressed distally, can push the proximal end portion of the probe that can pivot laterally to the outside of the recess.

Therefore, a device for the denervation of an ION in a bone is illustrated in Figure 25, comprising:

a fixed probe having a first electrode thereon in electrical connection with the power supply, and a pivoting probe comprising a second electrode having a distal part that pivotally engages the fixed probe.

The device that can pivot has both an active and a return electrode, and the device can be inserted through a single pedicle. The location of these electrodes may vary depending on the use of the device that can pivot. For example, when the active electrode is on the pivoting probe, instead of being on the proximal fixed pivot probe (as in Figure 25) the return electrode can be placed in a location on the pivoting probe that It is closer to the pivot.

In other embodiments, the locations of the active and return electrodes are reversed with respect to those described above.

In general, it is desirable to operate the present invention in a manner that produces a peak temperature in the target tissue between about 80 ° C and 95 ° C. When the peak temperature is below 80 ° C, temperatures outside the peak can quickly fall below approximately 45 ° C. When the peak temperature is above about 95 ° C, bone tissue exposed to that peak temperature may experience necrosis and cause carbonization. This carbonization reduces the electrical conductivity of the carbonized tissue, thus making it more difficult for RF current to pass through the target tissue beyond the carbonized zone and the target tissue beyond the carbonized zone to be resistively heated. In some embodiments, the peak temperature is preferably between 86 ° C and 94 ° C.

It is desirable to heat the volume of target tissue to a minimum temperature of at least 42 ° C. When the tissue experiences a temperature above 42 ° C, the nerves inside the target tissue may be desirably damaged. However, it is believed that denervation is a function of the total amount of energy delivered to the target tissue, that is, both the exposure temperature and the exposure time determine the total dose of energy delivered. Therefore, if the temperature of the target tissue reaches only about 42 ° C, it is then believed that the exposure time of the volume of target tissue at that temperature should be at least about 30 minutes and preferably at least 60 minutes in order of delivering the dose of energy that is considered necessary to denervate the nerves inside the target tissue.

Preferably, it is desirable to heat the volume of target tissue to a minimum temperature of at least 50 ° C. If the target tissue temperature reaches approximately 50 ° C, then it is believed that the exposure time of the target tissue volume at that temperature needs to be only in the range of about 2 minutes to 10 minutes to achieve denervation.

More preferably, it is desirable to heat the volume of target tissue to a minimum temperature of at least 60 ° C. If the temperature of the target tissue reaches approximately 60 ° C, it is then believed that the exposure time of the volume of target tissue at that temperature only needs to be in the range of about 0.01 minutes to 1.5 minutes to achieve denervation, preferably from 0.1 minutes to 0.25 minutes.

Usually, the period of time that an ION is exposed to therapeutic temperatures is generally related to the amount of time in which the electrodes are activated. However, because it has been observed that the total heating zone remains relatively hot even after the power has been turned off (and the electric field has been removed), the exposure time may include a period of time in which the current does not run through the electrodes.

In general, the more separate the electrodes are, the greater the probability that the ION is contained within the total heating zone. Therefore, in some embodiments, the electrodes are placed with a separation of at least 5 mm, more preferably with a separation of at least 10 mm. However, if the electrodes are too far apart, the electric field adopts an extreme bicircular shape in an undesirable way. Therefore, in many preferred embodiments, the electrodes are separated by a distance between 5 mm and 25 mm, more preferably between 5 mm and 15 mm, more preferably between 10 mm and 15 mm.

In some embodiments, it is desirable to heat the target tissue such that at least about 1 cc of bone tissue experiences the minimum temperature. This volume corresponds to a sphere that has a radius of approximately 0.6 cm. Alternatively, it is desirable to heat the target tissue such that the minimum temperature is achieved for each part of the bone no more than 0.6 cm from the point that the peak temperature experiences.

More preferably, it is desirable to heat the target tissue such that at least about 3 cc of bone experiences the minimum temperature. This volume corresponds to a sphere that has a radius of approximately 1 cm.

In a preferred embodiment, the present invention provides a heated steady-state zone having a peak temperature between 80 ° C and 95 ° C (and preferably between 86 ° C and 94 ° C), and heats at least 1 cc of bone (and preferably at least 3 cc of bone) at a temperature of at least 50 ° C (and preferably 60 ° C).

The system of the invention can therefore be used in a method of therapeutically treating a vertebral body having a BVN, comprising the steps of:

provide an energy device that has an active and a return electrode, insert the active electrode inside the vertebral body, insert the return electrode inside the vertebral body, and apply a voltage difference of a frequency high enough between the active and return electrodes to generate a current between them to produce a total heating zone that has a diameter of at least 0.5 cm and a steady state temperature of at least 50 ° C.

As indicated above, a peak temperature below about 100 ° C is desirable in order to avoid carbonization of adjacent tissue, vapor formation and tissue bursts. In some embodiments, this is achieved by providing the power supply with feedback means that allow the peak temperature inside the heating zone to be maintained at a desired target temperature, such as 90 ° C. In some embodiments, between approximately 24 watts and 30 watts of power are first supplied to the device in order to quickly heat the relatively cold bone, obtaining maximum amperage inside for approximately 10 to 15 seconds. As the bone is further heated to the target temperature, the feedback means gradually reduces the power input to the device to approximately 6 to 10 watts.

If the active electrode does not have active cooling means, it may become subject to conductor heating by the heated tissue, and the resulting increased temperature in the electrode can adversely affect the behavior by carbonizing the adjacent bone tissue. Accordingly, in some embodiments an active cold tip electrode may be employed. The cooled electrode helps keep the electrode temperature at a desired temperature. Active cooled tip electrodes are known in the art. Alternatively, the power supply can be designed to provide a pulse energy input. It has been determined that emitting the pulse current favorably allows heat to dissipate from the electrode tip, and thus the active electrode remains relatively cooler.

The following section refers to the general structure of the energy devices described above.

The apparatus may comprise an electrosurgical probe having a tree with a proximal end, a distal end, and at least one active electrode at or near the distal end. A connector is provided at or near the proximal end of the shaft to electrically couple the active electrode to a high frequency voltage source. In some embodiments, a return electrode coupled to the voltage source separates a sufficient distance from the active electrode to substantially avoid or minimize the occurrence of short circuits between them. The return electrode can be provided in one piece with the probe shaft or it can be separated from the shaft.

The electrosurgical probe or catheter may comprise a tree or a handpiece that has a proximal end and a distal end that supports one or more electrode terminal (s). The tree or handpiece can assume a wide variety of configurations, the main purpose being to mechanically support the active electrode and allow the treating physician to manipulate the electrode from a proximal end of the tree. The shaft can be rigid or flexible, with flexible shafts that are optionally combined with a generally rigid outer tube for mechanical support. The flexible shafts can be combined with tensile wires, actuators with shape memory effect, and other known mechanisms to effect a selective deflection of the distal end of the shaft to facilitate the positioning of the electrode arrangement. The shaft will normally include a plurality of wires or other conductive elements that extend axially therethrough to allow connection of the electrode arrangement to a connector at the proximal end of the shaft.

Preferably, the tree may be a rigid needle that is introduced through percutaneous penetration into the patient. However, for endoscopic procedures inside the spine, the tree will have an adequate diameter and length to allow the surgeon to reach the target site (for example, a disk) by placing the tree through the thoracic cavity, the abdomen or similar Therefore, the tree will usually have a length in the range of about 5.0 to 30.0 cm, and a diameter in the range of about 0.2 mm to about 10 mm. In any of these embodiments, the tree can also be introduced through rigid or flexible endoscopes.

The probe will include one or more active electrode (s) to apply electrical energy to tissues inside the spine. The probe may include one or more return electrode (s), or the return electrode may be placed on the patient's back, such as a dispersive panel. In one or another embodiment, sufficient electrical energy is applied through the probe to the active electrode (s) to necrot the blood supply

or the nerves inside the vertebral body.

The electrosurgical instrument may also be a catheter that is placed percutaneously and / or endoluminally inside the patient by insertion through a conventional or specialized guided catheter, or the invention may include a catheter having an electrode active or an arrangement of electrodes in one piece with its distal end. The catheter shaft can be rigid or flexible, with flexible shafts that are optionally combined with a generally rigid outer tube for mechanical support. Flexible shafts can be combined with tensile wires, actuators with shape memory effect, and other known mechanisms to effect a selective deflection of the distal end of the shaft to facilitate the positioning of the electrode or electrode arrangement. The catheter shaft will normally include a plurality of wires or other conductive elements that extend axially therethrough to allow connection of the electrode or electrode arrangement and the return electrode to a connector at the proximal end of the catheter shaft. The catheter shaft may include a guidewire to guide the catheter to the target site, or the catheter may comprise an orientable guiding catheter. The catheter may also include a substantially rigid distal end portion to increase the torque control of the distal end portion as the catheter is further advanced into the patient's body. Specific deployment means will be described in detail in connection with the figures below in this document.

Electrically conductive wires can run freely inside the inner surface of the catheter in a non-locked mode, or inside multiple lights inside the inner surface of the catheter.

The tip region of the instrument may comprise many independent electrode terminals that are designed to deliver electrical power in the vicinity of the tip. The selective application of electrical energy is achieved by connecting each individual electrode terminal and the return electrode to a power source that has independently controlled or limited current channels. The return electrode (s) may comprise a single tubular element of conductive material proximal to the electrode arrangement. Alternatively, the instrument may comprise an arrangement of return electrodes at the distal tip of the instrument (together with the active electrodes) to maintain electrical current at the tip. The application of high frequency voltage between the return electrode (s) and the electrode arrangement results in the generation of high electric field intensities at the distal tips of the electrode terminals with the conduction of a current of high frequency from each individual electrode terminal to the return electrode. The flow of current from each individual electrode terminal to the return electrode (s) is controlled by either active or passive means, or a combination thereof, to deliver electrical energy to the surrounding conductive fluid to while minimizing the delivery of energy to the surrounding (non-objective) tissue.

The temperature probes associated with the apparatus may preferably be arranged on or inside the electrode holder; between the electrodes (which is preferred in bipolar embodiments); or inside the electrodes (which is preferred for monopolar embodiments). In some embodiments in which the electrodes are placed on either side of the ION, a temperature probe is disposed between the electrodes or at the electrodes. In alternative embodiments, the drop-down portion of the temperature probe comprises a metal with memory effect.

The electrode terminal (s) are preferably supported inside or by an inorganic insulating support that is placed near the distal end of the instrument shaft. The return electrode can be found on the instrument shaft, on another instrument or on the external surface of the patient (i.e., a dispersive panel). The immediate proximity of the double needle design with respect to the intraosseous nerve makes a bipolar design more preferable because it minimizes the flow of current through the non-target tissue and surrounding nerves. Therefore, the return electrode preferably either forms a single piece with the instrument body, or is another instrument that is in the immediate vicinity thereof. The proximal end of the instrument (s) will include the appropriate electrical connections to couple the return electrode (s) and the electrode terminal (s) to a high frequency power source, such as a generator electrosurgical

The active electrode (s) can have an active surface or part with surface geometries shaped to favor the electric field strength and the associated current density along the leading edges of the electrodes Suitable surface geometries can be obtained by creating electrode shapes that preferably include sharp edges, or creating roughnesses or other surface roughness on the active surface (s) of the electrodes. The electrode forms according to the present invention may include the use of formed wire (for example, by pulling a round wire through a forming matrix) to form electrodes with a variety of cross-sectional shapes, such as square , rectangular, L-shaped or V-shaped, or similar. The electrode edges can also be created by removing a portion of the elongated metal electrode to reshape the cross section. For example, the material can be rectified along the length of a round or hollow wire electrode to form D or C shaped wires, respectively, with edges oriented towards the cutting direction. Alternatively, the material can be removed at intervals with little separation along the length of the electrode to form transverse grooves, notches, wires or the like along the electrodes. In other embodiments, the probe may be sectorized such that a given circumference comprises an electrode region and an inactive region. In some embodiments, the inactive region is masked.

The return electrode is usually separated proximally with respect to the active electrode (s) as appropriate. In most of the embodiments described herein, the distal edge of the exposed surface of the return electrode separates approximately 5 to 25 mm from the proximal edge of the exposed surface of the electrode (s). ) active (s), in double needle inserts. Of course, this distance can vary with different voltage ranges, electrode geometry and depend on the proximity of the tissue structures to the active and return electrodes. The return electrode will usually have an exposed length in the range of about 1 to 20 mm.

The application of a high frequency voltage between the return electrode (s) and the electrode terminal (s) for a suitable time interval modifies the target tissue.

The devices may use a single active electrode terminal or an arrangement of separate electrode terminals around the distal surface of a catheter or probe. In the latter case, the electrode arrangement typically includes a plurality of electrode terminals of limited current and / or power controlled independently to selectively apply electrical energy to the target tissue while limiting the application of unwanted electrical energy. to the tissue and surrounding environment that results from power dissipation in surrounding electrically conductive fluids, such as blood, normal saline, and the like The electrode terminals can be of limited current independently by isolating the terminals from each other and connecting each terminal to a separate power source that is isolated from the other electrode terminals. Alternatively, the electrode terminals can be connected to each other at either the proximal or distal ends of the catheter to form a single wire that couples to a power source.

In a configuration, Each individual electrode terminal in the electrode arrangement is electrically isolated from all other electrode terminals in the arrangement inside said instrument and is connected to a power source that is insulated from each other. electrode terminals in the arrangement or a set of circuits that limit or interrupt the flow of current to the electrode terminal when a low resistivity material (for example, blood) results in a path of lower impedance between the return electrode and the individual electrode terminal. The isolated power sources for each individual electrode terminal can be separate power supply circuits that have internal impedance characteristics that limit the power to the associated electrode terminal when a low impedance return path is found. By way of example, the isolated power source may be a user selectable constant current source. In this embodiment, the lower impedance paths will automatically result in lower resistive heating levels because the heating is proportional to the square of the operating current multiplied by the impedance. Alternatively, a single power source can be connected to each of the electrode terminals through switches that can be operated independently, or by independent current limiting elements, such as coils, capacitors, resistors and / or combinations of the same. The current limiting elements may be provided in the instrument, in the connectors, in the cable, in the controller or along the conductor path from the controller to the distal tip of the instrument. Alternatively, resistance and / or capacity may take place on the surface of the active electrode terminal (s) due to oxide layers that form selected electrode terminals (eg, titanium or a resistive coating on the surface of metal, such as platinum).

The active electrode may comprise an electrode arrangement having a plurality of electrically insulated electrode terminals that are disposed on a contact surface, which can be a flat or non-flat surface and which can be found at the distal tip or above a lateral surface of the tree, or above both the tip and the lateral surface (s). The electrode arrangement will include at least two and preferably more electrode terminals, and may further comprise a temperature sensor. In a preferred aspect, each electrode terminal will be connected to the proximal connector by an electrically insulated conductor disposed inside the shaft. The conductors allow an independent electrical coupling of the electrode terminals to a high frequency power supply and to a control system with an optional temperature monitor for the operation of the probe. The control system preferably incorporates active and / or passive current limiting structures, which are designed to limit current flow when the associated electrode terminal is in contact with a low resistance return path back to the electrode. return.

The use of such electrode arrangements in electrosurgical procedures is particularly advantageous because it has been determined to limit the depth of tissue necrosis without substantially reducing power delivery. The voltage that is applied to each electrode terminal results in the electrical energy being imparted to any body structure that comes into contact with, or is placed in the immediate vicinity of, the electrode terminal, in which a flow of Current across all paths of low electrical impedance are preferably but not necessarily limited. Because some of the needles are hollow, a conductive fluid can be added through the needle and into the bone structure for the purpose of reducing electrical impedance and filling the spaces in the spongy bone to make them better conductors. for the needle

It should be clearly understood that the invention is not limited to electrically insulated electrode terminals, or even a plurality of electrode terminals. For example, the arrangement of active electrode terminals can be connected to a single conductor that extends through the catheter shaft to a source of high frequency current power. Alternatively, the instrument may incorporate a single electrode that extends directly through the catheter shaft or that connects to a single conductor that extends to the power source. The active electrode (s) may have balloon shapes, balloon eye shapes, spring shapes, twisted metal shapes, cone shapes, annular or solid tube shapes or the like. Alternatively, the electrode (s) may comprise a plurality of filaments, rigid or flexible brush electrode (s), edge effect brush electrode (s) on a tree side surface, continuous electrode (s) (s) or the like.

The voltage difference that is applied between the return electrode (s) and the electrode terminal (s) will be at a high frequency or radiofrequency, usually between about 50 kHz and 20 MHz, usually between about 100 kHz and 2.5 MHz, preferably between approximately 400 kHz and 1,000 kHz, often less than 600 kHz, and often between approximately 500 kHz and 600 kHz. The RMS voltage (mean square value) that is applied will normally be in the range of between about 5 volts and 1,000 volts, preferably in the range of about 10 volts and 200 volts, often between about 20 and 100 volts depending on the electrode terminal size, operating frequency and operating mode of the particular procedure. Lower peak to peak voltages will be used for tissue coagulation, thermal heating of tissue, or collagen contraction and will usually be in the range of 50 to 1,500, preferably 100 to 1,000 and more preferably 120 to 400 volts. peak to peak As discussed above, the voltage is normally delivered continuously with a sufficiently high frequency (for example, of the order of 50 kHz to 20 MHz) (compared to for example, lasers that claim small depths of necrosis, which are generally pulsed from approximately 10 to 20 Hz). In addition, the duty cycle of the sine wave (ie, the cumulative time in any interval of one second in which energy is applied) is preferably of the order of approximately 100% for the present invention, compared to pulsed lasers. which usually have a duty cycle of approximately 0.0001%.

The preferred power source of the present invention delivers a high frequency current that can be selected to generate average power levels that vary between several milliwatts and tens of watts per electrode, depending on the volume of target tissue being heated, and / or of the maximum allowable temperature selected for the instrument tip. The power source allows the user to select the power level according to the specific requirements of a particular procedure.

The power source can be of limited current or otherwise controlled, so that unwanted heating of the target tissue or surrounding (non-target) tissue does not take place. In a presently preferred embodiment of the present invention, current limiting coils are placed in series with each independent electrode terminal, in which the coil inductance is in the range of 10! H to 50,000! H, depending of the electrical properties of the target tissue, the desired heating rate of the tissue and the operating frequency. Alternatively, capacitor-coil (LC) circuit structures may be employed, as previously described in US-5697909. Additionally, current limiting resistors can be selected. Preferably, microprocessors are used to monitor the measured current and control the output to limit the current.

The area of ​​the tissue treatment surface can vary widely, and the tissue treatment surface can assume a variety of geometries, with particular areas and geometries that are selected for specific applications. The geometries can be flat, concave, convex, hemispherical, conical, "in-line" linear or virtually any other regular or irregular shape. More frequently, the active electrode (s) or electrode terminal (s) will be formed at the distal tip of the electrosurgical instrument tree, often being flat, disk-shaped, or hemispherical surfaces. for use in reperfiling procedures or being linear provisions for use in court. Alternatively or additionally, the active electrode (s) can be formed on the lateral surfaces of the electrosurgical instrument shaft (for example, in the form of a spatula), which facilitates access to certain structures of the body in endoscopic procedures.

The devices of the present invention can be used suitably for insertion into any hard tissue in the human body. In some embodiments, the hard tissue is bone. In other embodiments, the hard tissue is cartilage. In preferred embodiments, when bone is selected as the tissue of choice, the bone is a vertebral body. Preferably, the present invention is adapted to pierce the hard cortical bone layer and penetrate at least a portion of the underlying spongy bone. In some embodiments, the probe progresses inside the bone at a distance of at least Y from the cross section of the bone defined by the advance of the probe.

In some embodiments, the present invention is practiced in vertebral bodies substantially free of tumors. In others, the present invention is practiced in vertebral bodies that have tumors.

The system of the invention can be used in a method of therapeutically treating a healthy vertebral body having a BVN, which comprises the steps of:

provide an energy device that has an active and a return electrode, insert the active electrode into the healthy vertebral body, insert the return electrode into the healthy vertebral body, place the active electrode on a first side of the healthy vertebral body and the return electrode on a second side of the healthy vertebral body, and apply a voltage difference of a frequency high enough between the active and return electrodes to generate a current between them to produce a total heating zone to heat therapeutically the BVN.

In a device that uses two separate probes, the device is inserted into the hard tissue (preferably bone, more preferably the vertebral body) through two access points. In preferred arrangements, the pair of separate probes is adapted to denervate the BVN and be introduced through separate pedicles in a transpedicular manner. In other arrangements, each of the pair of separate probes is introduced into the vertebral body extrapedicularly. In other arrangements, a first of the pair of separate probes is introduced into the vertebral body extrapedicularly and the second is introduced into the vertebral body transpedicularly. In embodiments that use a single articulated device, the device is introduced through a single pedicle.

Referring now to Figure 26, in some arrangements, the target region of the BVN is located inside the spongy part of the bone (i.e., into the region of the outer cortical bone), and proximal to the point of J junction of the BVN having a plurality of branches. Treatment in this region is advantageous because only one part of the BVN needs to be treated effectively to denervate the entire system. In contrast, the treatment of BVN in locations further downstream than the junction point requires the denervation of each branch.

The system can therefore be used in a procedure to therapeutically treat a vertebral body that has an outer cortical bone region and an inner spongy bone region, and a BVN that has a trunk that extends from the cortical bone region outside towards the inside of the inner spongy region and branches that extend from the trunk to define a BVN junction point, which comprises the steps of:

insert an energy device inside the vertebral body, and apply energy exclusively inside the spongy bone region inside the vertebral body between, but not including the BVN junction point and the outer cortical bone region, to denervate the BVN.

Usually, the treatment according to this embodiment can be carried out by placing the electrodes in the region of the vertebral body that is between 60% (point A) and 90% (point B) of the distance between the anterior and posterior ends of the body vertebral, as shown in figure 26.

Example I

This predictive example describes a preferred embodiment of a double probe of the type described above.

First, after induction of an adequate amount of local anesthesia, the human patient is placed in a prone position on the table. The C-arm of an X-ray device is positioned such that X-rays are perpendicular to the axis of the spine. This positioning provides a lateral view of the vertebral body, which allows the surgeon to see the access of the device inside the vertebral body.

Next, a stylet with a cannula comprising an inner stylet and an outer cannula are inserted into the skin on each of the respective pedicles so that the distal tip of each stylet is in the immediate vicinity of the respective pedicle.

Next, the probe is advanced internally into the body such that the stylet tips pierce through the skin, into and through the pedicle, and then into the vertebral body. The stylet is advanced until the tips reach the anterior – posterior midline of the vertebral body.

Next, the stylet is removed and the probe is inserted into the cannula and progressed until the first and second electrodes each reach the midline of the vertebral body. The location of the two probes is shown from various perspectives in Figure 27 a – d.

Next, the power supply is activated to provide a voltage between the first and second electrodes. The amount of voltage across the electrodes is sufficient to produce an electric current between the first and second electrodes. This current provides a resistive heating of the tissue disposed between the electrodes in an amount sufficient to raise the temperature of the local part of the BVN to at least 45 ° C, thereby denervating the BVN.

Example II

This example describes the effectiveness of heating a large area of ​​a vertebral body with a bipolar energy device.

A pair of probes were inserted into a vertebral body of a porcine corpse such that the electrode tips were substantially in the midline and were approximately 4 mm apart. Each electrode had a cylindrical shape, a length of approximately 20 mm, and a diameter of approximately 1.65 mm2 (16 gauge) to produce a surface area of ​​approximately 100 mm2.

Next, and referring in this case to Figures 28a and 28b, thermocouples 0 to 14 were placed inside the vertebral body at the 15 locations. Thermocouples 0 to 4 were placed midway between the electrode tips and were separated by a distance of 2 mm. Thermocouples 5 to 9 were placed approximately midway between the tips of the probe, and were vertically separated by a distance of 2 mm. Thermocouples 10 to 14 were placed along the distal part of the probe and were separated. for a distance of 5 mm.

Next, a potential difference of approximately 57 volts was applied across the electrodes, and the temperature rise in the tissue was recorded at the thermocouple locations. These temperatures are provided in Figures 29 a – c. In general, the temperature at each location rose steadily from approximately 22 ° C to its peak temperature in approximately 200 to 300 seconds, after which the feedback controls maintained peak temperatures.

Figures 30a and 30b provide the peak temperatures recorded for each thermocouple. The analysis of the result of Figure 17a and 17b reveals that peak temperatures between about 80 ° C and 95 ° C could be maintained over substantial distances. In particular, a temperature of 79.4 degrees was reached around 10 mm along the electrode (T11); temperatures of between 76.7 and 80.3 ° C were reached at a depth of approximately 4 mm inside the tissue (T5 and T9); and a temperature of 76.8 ° C was reached around 10 mm along the electrode (T3).

The positive results provided by this example are of great importance for the problem of therapeutic warming of IONs, and BVN in particular. In particular, the results of thermocouples T5 to 9 indicate that if an ION was along the z axis no more than 2 mm from the assumed center of the IRZ, then the ION can be treated sufficiently up to at least 80 ° C. Similarly, the results of thermocouples T0 to 4 indicate that as much as a length of 16 mm of ION can be treated sufficiently up to at least 80 ° C. Finally, the results of thermocouples T 10 to 14 indicate that the ION can move laterally with respect to the center in the IRZ by as much as 2 mm and at least about 10 mm in length can be treated sufficiently up to at least 80 ° C.

Example III

This example describes a preferred articulated probe embodiment of the present invention.

The initial steps described above in Example I are carried out in such a way that the articulated probe is suspended on the patient's skin and held in place by a ratchet-type gun. See figure 31a.

Next, the distal end of the articulated probe is inserted into a pedicle inside the skin such that the distal end of the fixed probe is in the immediate vicinity of the pedicle.

Referring next to Figure 31b, the probe is advanced internally into the body such that the distal tip penetrates through the skin, into and through the pedicle, and then into the vertebral body. The distal tip is progressed until it reaches approximately 30% beyond the anterior – posterior midline of the vertebral body.

Referring next to Figure 31c, the distal end of the push rod is inserted into the interior surface of the fixed probe and progressed until the angled part of the push rod comes into contact with the angled part of the probe that can pivot, thereby pushing the probe that can pivot outside the recess. The pivoting probe is then in a partially deployed mode.

Referring now to Figure 31d, the apparatus is slightly removed from the body. As this takes place, the bone that is disposed between the pivoting probe and the fixed probe prevents the pivoting probe from being removed along with the fixed probe, but rather forces the opening of the pivot means , thus bringing the axis of the probe that can pivot to a substantially normal position with respect to the axis of the fixed probe. The pivoting probe is then in an extended mode.

Next, the power supply is activated to provide a voltage between the first and second electrodes. The amount of voltage across the electrodes is sufficient to produce an electric current between the first and second electrodes. This current provides a resistive heating of the tissue disposed between the electrodes in an amount sufficient to raise the temperature of the local part of the BVN to at least 45 ° C, thereby denervating the BVN.

Next, the fixed probe is pushed forward to bring the probe that can pivot back into the recess.

Referring now to Figures 31 e, the probe is removed from the body.

Example IV

Referring now to Figure 32, an embodiment of a double articulated needle of the present invention is provided, in which each of the articulated needles is advanced downstream by the pedicles of the vertebral body, and each of the probes that can pivot is deployed at an angle of less than 90 degrees, so that the electrodes themselves on them are aligned in an essentially parallel relationship. Because the electric field produced by this embodiment is relatively uniform between the electrodes, the resulting total heating zone is also desirably homogeneous. Because the electrodes are deployed in the central back of the vertebral body, the BVN desirably desnervates near its trunk.