Patent Publication Number: US-2022218434-A1

Title: Devices, systems, and methods facilitating access to and mapping of target tissue

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of, and priority to, U.S. Provisional Patent Application No. 63/137,465, filed on Jan. 14, 2021, the entire contents of which are hereby incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates generally to tissue access and mapping and, more particularly, to devices, systems, and methods facilitating access to and mapping of target tissue, e.g., a spinal tumor within a vertebra, for performing a surgical task, e.g., ablation, on the target tissue. 
     BACKGROUND 
     Treatment of certain diseases requires destruction of malignant tissue growths, e.g., tumors. Tumor tissue can be destroyed via ablation, which involves heating the tumor tissue to sufficiently high temperatures to destroy, e.g., ablate, the tumor tissue while maintaining surrounding healthy tissue at lower temperatures to avoid irreversible damage to the surrounding healthy tissue. Such ablation may be accomplished by applying electromagnetic energy such as RF energy or microwave energy to the tumor tissue to heat and, thereby, ablate the tumor tissue. 
     Nerve pain and spinal metastases are some of the most common causes of severe pain among patients with cancer. Spinal tumor ablation using electromagnetic radiation can be used for the palliative treatment of painful metastases and nerve pain secondary to advanced cancer disease. Accessing and mapping the spinal tumor prior to performing the ablation facilitates effective ablation of the spinal tumor while inhibiting irreversible damage to the surrounding healthy tissue. 
     SUMMARY 
     As used herein, the term “distal” refers to the portion that is being described which is farther from an operator, while the term “proximal” refers to the portion that is being described which is closer to the operator. Terms including “generally,” “about,” “substantially,” and the like, as utilized herein, are meant to encompass variations, e.g., manufacturing tolerances, material tolerances, use and environmental tolerances, measurement variations, and/or other variations, up to and including plus or minus 10 percent. Further, any or all of the aspects described herein, to the extent consistent, may be used in conjunction with any or all of the other aspects described herein. 
     Provided in accordance with aspects of the present disclosure is a surgical access system including a cannula, a mapping spacer, and a trocar. The cannula includes a proximal base and an elongated cannula body extending distally from the proximal base. The mapping spacer is configured to releasably engage the proximal base of the cannula and includes first and second uprights defining a slot therebetween. The trocar includes a proximal handle and an elongated trocar body extending distally from the proximal handle to a distal cutting tip. The elongated trocar body is configured for insertion through the mapping spacer and the cannula such that the distal cutting tip extends distally from the elongated cannula body. In a first orientation of the trocar relative to the mapping spacer, the proximal handle is configured to abut the first and second uprights to inhibit extension of the distal cutting tip from the proximal base beyond an initial position. In a second orientation of the trocar relative to the mapping spacer, the proximal handle is configured to slide through the slot of the mapping spacer to enable extension of the distal cutting tip distally from the initial position towards an extended position. 
     In an aspect of the present disclosure, the mapping spacer includes markings disposed on at least one of the first or second uprights to enable determination of a depth of extension of the distal cutting tip from the initial position towards the extended position. In such aspects, the proximal handle of the trocar may include a reference point for comparison with the markings to enable determination of the depth of extension. 
     In another aspect of the present disclosure, the trocar is rotatable 90 degrees relative to the mapping spacer to transition between the first and second orientations. 
     In still another aspect of the present disclosure, the proximal handle includes first and second shoulders extending outwardly therefrom. In the first orientation of the trocar, the first and second shoulders are substantially aligned with the first and second uprights, respectively. In the second orientation, the first and second shoulders are substantially perpendicular relative to the first and second uprights. 
     In yet another aspect of the present disclosure, the proximal base of the cannula defines a coupler configured to releasably engage a coupler of the mapping spacer. The couplers, in aspects, may define complementary threading to enable threaded engagement of the mapping spacer with the proximal base of the cannula. 
     In still yet another aspect of the present disclosure, the proximal base of the cannula and a distal face of the mapping spacer include at least one of complementary alignment features or complementary engagement features to enable alignment or engagement, respectively, of the proximal base of the cannula and the mapping spacer with one another. 
     In another aspect of the present disclosure, a proximal face of the mapping spacer and the proximal handle of the trocar include at least one of complementary alignment features or complementary engagement features to enable alignment or engagement, respectively, of the mapping spacer and the proximal handle of the trocar in the first orientation of the trocar. 
     In another aspect of the present disclosure, the access system further includes an ablation device including an ablation probe configured for insertion through the elongated cannula body in the absence of the elongated trocar body. 
     In yet another aspect of the present disclosure, the elongated cannula body includes markings disposed thereon to enable determination of insertion thereof. Additionally or alternatively, the elongated cannula body includes a proximal section defining a first diameter, a distal section defining a second, smaller diameter, and a transition section extending between and interconnecting the proximal and distal sections. 
     A method of surgery in accordance with aspects of the present disclosure includes engaging a mapping spacer with a proximal base of a cannula, wherein the cannula includes an elongated cannula body extending distally from the proximal base. The method further includes inserting a trocar, in a first orientation, through the mapping spacer and the cannula until a proximal handle of the trocar abuts the mapping spacer to define an initial position wherein a distal cutting tip of the trocar extends distally an initial distance from the elongated cannula body. The method additionally includes advancing the cannula, the mapping spacer, and the trocar together with one another such that the distal cutting tip of the trocar is advanced distally through tissue. The proximal handle of the trocar is rotated from the first orientation to a second orientation such that the proximal handle is aligned with a slot defined through the mapping spacer. Thereafter, the trocar is advanced distally relative to the cannula and the mapping spacer such that the proximal handle slides distally through the slot of the mapping spacer and such that the distal cutting tip is advanced further distally through tissue from the initial position towards an extended position. 
     In an aspect of the present disclosure, the method further includes determining a distance the distal cutting tip is advanced from the initial position towards the extended position using markings on the mapping spacer. 
     In another aspect of the present disclosure, advancing the cannula, the mapping spacer, and the trocar together with one another includes advancing the distal cutting tip of the trocar to a proximal side of target tissue. Advancing the trocar distally relative to the cannula and the mapping spacer, in such aspects, may include advancing the distal cutting tip of the trocar through the target tissue to a distal side of the target tissue. A dimension of the target tissue may thus be determined using markings on the mapping spacer. 
     In still another aspect of the present disclosure, the method further includes withdrawing the trocar, disengaging the mapping spacer from the proximal base of the cannula, inserting an ablation probe through the cannula such that a distal portion of the ablation probe extends distally from the elongated cannula body into target tissue, and energizing the ablation probe to ablate the target tissue. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects and features of the present disclosure will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals identify similar or identical elements. 
         FIG. 1A  is a perspective view of an access system provided in accordance with the present disclosure including a cannula, a mapping spacer, and a trocar, wherein the access system is disposed in an insertion configuration; 
         FIG. 1B  is a perspective view of the access system of  FIG. 1A , wherein the access system is disposed in a mapping configuration; 
         FIG. 2  is an exploded, perspective view of the access system of  FIG. 1A ; 
         FIG. 3  is a perspective view of the access system of  FIG. 1A  disposed in the insertion configuration and extending into a vertebra with the trocar disposed at a proximal side of a spinal tumor to be ablated; 
         FIG. 4  is a perspective view of the access system of  FIG. 1A  disposed in the mapping configuration and extending into a vertebra with the trocar disposed through the spinal tumor to a distal side thereof; 
         FIG. 5  is a side view of an ablation device configured for use with the access system of  FIG. 1A ; and 
         FIG. 6  is a perspective view of the ablation device of  FIG. 5  inserted through the cannula of the access system of  FIG. 1A , into the vertebra, and into the spinal tumor for ablating the spinal tumor. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A, 1B, and 2  illustrate an access system in accordance with the present disclosure shown generally identified by reference numeral  10 . Access system  10  may be utilized to facilitate access to and mapping of, for example, a spinal tumor within a vertebra to facilitate spinal tumor ablation, as detailed below, or may be utilized to facilitate access to and/or mapping of other tissue structures, tissue at other anatomical locations, and/or for otherwise treating tissue. Access system  10  generally includes a cannula  100 , a mapping spacer  200 , and an insertion device such as a trocar  300 . 
     Cannula  100  of access system  10  includes an elongated tubular body  110  and a proximal base  140 . Elongated cannula body  110  defines a lumen  112  extending longitudinally therethrough. Elongated cannula body  110  may define a substantially constant diameter along its length, may include two or more sections of different diameter, and/or may include one or more tapered sections. For example, elongated cannula body  110  may include a proximal section  114  of a first diameter and a distal section  116  of a second, smaller diameter. A transition section  118  may be disposed between and interconnect the proximal and distal sections  114 ,  116  to define a smooth transition between the proximal and distal sections  114 ,  116 . Other configurations are also contemplated. In aspects, elongated cannula body  110  defines a plurality of depth markers  120  (each including a demarcation line and a reference indicium, for example) spaced-apart along at least a portion of the length of elongated cannula body  110 . Depth markers  120  may be configured to facilitate visual, echogenic, radiogenic, fluorogenic, and/or other suitable identification of an insertion depth of elongated cannula body  110  into a patient and/or an anatomical structure within the patient. 
     Proximal base  140  of cannula  100  includes a base body  142 , a neck  144  extending distally from base body  142 , and a coupler  146  extending proximally from base body  142 . Base body  142  is configured to facilitate grasping and manipulation by an operator, and defines a pair of outwardly-extending shoulders  148 . One or both of shoulders  148  may include an alignment feature  152 , e.g., a recess, and/or an engagement feature  154 , e.g., a cantilever engagement arm. Neck  144 , as noted above, extends distally from base body  142  and supports a proximal end portion of elongated cannula body  110 , e.g., therein, thereon, or otherwise attached thereto. Coupler  146  extends proximally from base body  142  and cooperates with base body  142  and neck  144  to define a lumen  156  extending longitudinally through proximal base  140 . Lumen  156  is disposed coaxially and in communication with lumen  112  of elongated cannula body  110 . Coupler  146  includes threading  158  or other suitable engagement feature(s) on an exterior surface thereof or otherwise positioned. 
     Continuing with reference to  FIGS. 1A-2 , mapping spacer  200  of access system  10  may be formed as a single, monolithic component, e.g., via injection molding, 3D printing, etc., or may be formed via attachments of plural components. Mapping spacer  200  defines a generally U-shaped configuration and having a pair of spaced-apart uprights  212  separated by a slot  214  and interconnected at distal ends thereof via a distal backspan  216 . Either or both uprights  212  includes a plurality of depth markers  218  spaced-apart along at least a portion of the length of mapping spacer  200 . Depth markers  218  may be embossed on either or both sides of either or both uprights  212 , e.g., during formation of mapping spacer  200 , or may be adhered, printed, or otherwise attached on either or both sides of either or both uprights  212 . Depth markers  218 , as detailed below, are configured to facilitate visual identification of a depth of advancement of an insertion device, e.g., trocar  300 , from elongated cannula body  110  of cannula  100 . One or both of uprights  212  may additionally include an alignment feature  220 , e.g., a tab, and/or an engagement feature (not shown), e.g., a catch, on a distal face  213   a  thereof. Alternatively or additionally, one or both of uprights  212  may include an alignment feature  221 , e.g., a recess, a proximal face  213   b  thereof. 
     Distal backspan  216  of mapping spacer  200  includes a coupler  222  defining a lumen  224  extending longitudinally therethrough. Coupler  222  includes threads  226  or other suitable engagement feature(s) on an interior surface thereof surrounding lumen  224  or otherwise positioned. Threading  226  of coupler  222  of mapping spacer  200  is complementary to threading  158  of coupler  146  of cannula  100  to enable threaded engagement of coupler  222  about coupler  146 , although other suitable complementary engagements are also contemplated. Upon sufficient threaded engagement of coupler  222  of mapping spacer  200  about coupler  146  of cannula  100 , the alignment feature  220  of mapping spacer  200  is engaged with the alignment feature  142  of cannula  100 , e.g., the tab is received within the recess, and the engagement feature  154  of cannula  100  is engaged with the engagement feature (not shown) of mapping spacer  200 , e.g., the cantilever engagement arm is snap-fit into engagement within the catch. In this manner, mapping spacer  200  is secured to cannula  100  in fixed orientation relative thereto. In this engaged condition, lumen  224  of mapping spacer  200 , lumen  156  of proximal base  140  of cannula  100 , and lumen  112  of elongated cannula body  110  of cannula  100  are coaxially disposed and in communication with one another to permit insertion an insertion device, e.g., trocar  300 , therethrough. 
     Referring still to  FIGS. 1A-2 , trocar  300  of access system  10  includes an elongated trocar body  310  and a proximal handle  320  supporting elongated trocar body  310  at a proximal end of elongated trocar body  310 . Elongated trocar body  310  defines a suitable diameter and length to enable insertion of elongated trocar body  310  through mapping spacer  200  and cannula  100  and into an internal surgical site. Elongated trocar body  310  may include a distal cutting tip  312  configured to penetrate tissue including hard tissue such as bone. Distal cutting tip  312  may define one or more cutting points, cutting edges, and/or other suitable cutting features to facilitate penetrating, e.g., malleting, tissue to define an access pathway to an internal surgical site, e.g., a spinal tumor within a vertebra. Elongated trocar body  310  may be rigid, semi-rigid, malleable, resiliently flexible, or otherwise configured and may define a linear configuration or a pre-bent configuration. Elongated cannula body  110  of cannula  100  may, similarly or differently, be rigid, semi-rigid, malleable, resiliently flexible, or otherwise configured and may define a linear configuration or a pre-bent configuration. In this manner, elongated cannula body  110  of cannula  100  and elongated trocar body  310  of trocar  300  may be configured to enable use of access system  10  to facilitate access to any anatomical location from any directional approach. 
     Proximal handle  320  of trocar  300  supports the proximal end of elongated trocar body  310  and includes a pair of outwardly-extending shoulders  324 . Shoulders  324  facilitate grasping and manipulation of proximal handle  320 . One or both of shoulders  324  may further include an alignment feature  326  (and/or an engagement feature), e.g., a tab, extending therefrom. In aspects, shoulder  324  includes an alignment feature  326  (and/or an engagement feature) on a front side of proximal handle  320  while the other shoulder  324  includes an alignment feature  326  (and/or an engagement feature) on an opposite, rear side of proximal handle  320 . In such aspects, mapping spacer  200  may be configured with an alignment feature  221  (and/or an engagement feature), e.g., a tab, on the proximal face  213   b  of one of the uprights  212  on a front side thereof and another alignment feature  221  (and/or an engagement feature), e.g., a tab, on the proximal face  213   b  of the other upright  212  on a rear side thereof. In this manner, with shoulders  324  of proximal handle  320  of trocar  300  substantially aligned with uprights  212  of mapping spacer  200 , elongated trocar body  310  of trocar  300  may be inserted through mapping spacer  200  and cannula  100  until proximal handle  320  abuts proximal face  213   b  of mapping spacer  200 , whereby alignment features  221  are received within alignment features  326  to rotationally fix and, in some aspects, engage (via engagement features), proximal handle  320  of trocar  300  and mapping spacer  200  with one another (see  FIG. 1A ). 
     Referring in particular to  FIG. 1A , with mapping spacer  200  engaged with cannula  100  as detailed above, and trocar  300  abutting (and, in aspects, engaged with) mapping spacer  200  in the aligned orientation of shoulders  324  of proximal handle  320  relative to uprights  212  of mapping spacer  200 , access system  10  defines an insertion configuration wherein distal cutting tip  312  of elongated trocar body  310  of trocar  300  is disposed in an initial position extending a relatively minimal distance from the distal end of elongated cannula body  110  of cannula  100  and is inhibited from further extension therefrom via the abutment (and engagement, in aspects) of proximal handle  320  of trocar  300  with uprights  212  of mapping spacer  200 . In this insertion configuration, access system  10  may be utilized to penetrate tissue to a position wherein distal cutting tip  312  of elongated trocar body  310  is positioned proximally adjacent target tissue, e.g., a spinal tumor to be ablated, as detailed below. In this manner, an access pathway to the target tissue is created. 
     With additional reference to  FIG. 1B , in order to permit advancement of elongated trocar body  310  relative to cannula  110  and mapping spacer  200 , e.g., to enable mapping of target tissue, proximal handle  320  of trocar  300  is rotated 90 degrees relative to mapping spacer  200  such that shoulders  324  of proximal handle  320  of trocar  300  are oriented substantially perpendicularly relative to uprights  212  of mapping spacer  200  and in alignment with the open sides of slot  214  of mapping spacer  200 . As can be appreciated, alignment features  221 ,  326  (and any engagement features of trocar  300  and mapping spacer  200 ) are disengaged from one another upon such rotation of trocar  300 . With proximal handle  320  disposed substantially perpendicular relative to mapping spacer  200  and in substantial alignment with the open sides of slot  214  of mapping spacer  200 , access system  10  defines a mapping configuration wherein distal cutting tip  312  of elongated trocar body  310  may be advanced distally into the target tissue and relative to mapping spacer  200  and cannula  100 . That is, proximal handle  320  of trocar  300  may be advanced distally through slot  214  of mapping spacer  200  to extend distal cutting tip  312  of elongated trocar body  310  of trocar  300  from the initial position further distally relative to the distal end of elongated cannula body  110  of cannula  100  to an extended position, e.g., through the target tissue to the distal side of the target tissue. The distance distal cutting tip  312  is advanced from the initial position to the extended position and, thus, the diameter or other dimension through the target tissue, is determined by comparing the position of a reference point  330  of proximal handle  320  to depth markers  218  of uprights  212  of mapping spacer  200 . Depth markers  218  may be disposed at consistent intervals, include indicia, and/or may otherwise be configured to readily enable determination of the extension distance of distal cutting tip  312 . Reference point  330  of proximal handle  320  may be a distal face of proximal handle  320  (see  FIG. 2 ) or any other suitable structural feature of or marking on proximal handle  320 . 
     Turning to  FIGS. 3-4 , in conjunction with  FIG. 2 , the use of access system  10  to access and map a spinal tumor “S” within a vertebra “V” is detailed. Initially, with access system  10  disposed in the insertion configuration, access system  10 , led by distal cutting tip  312  of elongated trocar body  310  of trocar  300 , is advanced, e.g., through a skin incision, to a position adjacent a pedicle “P” of the vertebra “V.” Thereafter, access system  10  is advanced further distally whereby distal cutting tip  312  is malleted through the vertebra “V” to a position adjacent a proximal side of the spinal tumor “S.” Once this position, shown in  FIG. 3 , is achieved, an access pathway to the spinal tumor “S” is established. 
     With distal cutting tip  312  malleted through the vertebra “V” into position adjacent the proximal side of the spinal tumor “S,” proximal handle  320  is rotated 90 degrees to transition access system  10  from the insertion configuration to the mapping configuration and, thereafter, proximal handle  320  is advanced distally through slot  214  of mapping spacer  200  to advance distal cutting tip  312  through the spinal tumor “S” to the distal side thereof. Reference point  330  of proximal handle  320  is compared to the appropriate depth marker  218  of mapping spacer  200  to enable determination of the extension distance of distal cutting tip  312  and, thus, the distance across the spinal tumor “S” from the proximal side thereof to the distal side thereof. The above access and mapping may be performed with the aid of fluoroscopy, ultrasound, endoscopy, or other suitable guidance. As can be appreciated, access system  10  enables the above-detailed access and mapping without requiring additional tools and/or tool exchange. 
     Referring also to  FIGS. 5 and 6 , in conjunction with  FIG. 2 , with an access pathway to the spinal tumor “S” establish and with the spinal tumor “S” mapped, trocar  300  may be withdrawn from cannula  100  and mapping spacer  200  and mapping spacer  200  may be disengaged and removed from cannula  100 , leaving cannula  100  in position. Based on the results of the mapping of the spinal tumor “S,” a suitable ablation probe may be selected to enable appropriate access to and effective ablation of the spinal tumor “S” while inhibiting irreversible damage to the surrounding healthy tissue. This selection may be based on, for example, a length, diameter, ablation zone volume, operational temperature(s), shape (e.g., curvature or linearity), energy modality (e.g., bipolar RF, monopolar RF, microwave, etc.), features (e.g., fluid cooled), and/or other aspects of the ablation probe. 
     An exemplary ablation device  400  is illustrated in  FIG. 5  generally including an ablation probe  410  and a connection hub  420 . Ablation probe  410  defines an elongated configuration and may be substantially linear, curved, or otherwise configured to facilitate accessing tissue to be ablated. In aspects, ablation probe  410  is at least partially formed form a resiliently flexible material, e.g., a shape memory material, to enable resilient flexion of ablation probe  410  to assume as desired trajectory for accessing tissue to be ablated. In additional or alternative aspects, ablation probe  410  is at least partially formed from a rigid, semi-rigid, malleable, and/or other suitable material(s). Ablation probe  410  includes a body  412  and a distal tip  414 . Distal tip  414  may be configured to facilitate penetration into and/or anchoring within tissue including hard tissue, e.g., bone. A portion of body  412  and/or distal tip  414  cooperate to define an operative portion of ablation probe  410  configured to deliver energy, e.g., bipolar RF, monopolar RF, microwave, etc., to tissue to heat and thereby ablate tissue. 
     Connection hub  420  supports a proximal end portion of body  412  of ablation probe  410  with ablation probe  410  extending distally from connection hub  420  to distal tip  414 . Connection hub  420  may function as a handle of ablation device  400 , enabling a user to grasp and manipulate connection hub  420  to thereby manipulate ablation probe  410 . Electrical connections such as, for example, electrode lead wires, e.g., an active electrode lead (in monopolar RF configurations) or positive and negative electrode leads (in bipolar RF configurations), sensing leads, e.g., for temperature sensors, thermocouple leads, and/or other energy-delivery, sensing, or communication leads extend from a cable (not shown) into connection hub  420  for connection to and/or routing through ablation probe  410 . Inflow and outflow tubing (not shown) may likewise extend into connection hub  420  for routing to and/or through ablation probe  410 , e.g., in configurations wherein cooling fluid is circulated through ablation probe  410  to cool ablation probe  410 . The cable (not shown) of ablation device  400  is configured to connect to an energy source (not shown), e.g., an electrosurgical generator, for powering and controlling ablation probe  410 . 
     Once the access pathway to the spinal tumor “S” is established, the spinal tumor “S” mapped, and trocar  300  and mapping spacer  200  removed, as noted above, ablation probe  410  of ablation device  400  is inserted through cannula  100  and, based upon the mapping of the spinal tumor “S,” is extended into the spinal tumor “S” to a suitable position for ablating the spinal tumor “S” (or initially ablating the spinal tumor “S,” in situations where multiple positions of ablation probe  410  and multiple ablations are required). Once positioned appropriately, ablation probe  410  may be energized to ablate the spinal tumor “S” while inhibiting damage to healthy surrounding tissue. Once the spinal tumor “S” is sufficiently ablated, ablation probe  410  and cannula  100  are removed from the patient. 
     It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). 
     While several configurations of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular configurations. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.