Abstract:
A tissue resecting device includes an elongated shaft having a central axis, a distal end, and an outer surface. An offset housing is mounted on the distal of the shaft and has a tissue-receiving window. The tissue-receiving window is offset radially outwardly from the outer surface of the shaft, and a moveable electrode is configured to move back and forth across the window to resect tissue which extends into the window. The offset housing improves visibility of the cutting window when viewed from endoscopes and other visualization apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Provisional No. 62/241,351 (Attorney Docket No. 42005-705.101), filed Oct. 14, 2015, the entire content of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to devices and methods for resecting and removing tissue from the interior of a patient&#39;s body, for example in a transurethral resection of prostate tissue to treat benign prostatic hyperplasia. 
         [0003]    Electrosurgical cutting devices often comprise a shaft or sleeve having a tissue extraction lumen with one or more radio frequency (RF) cutting blades arranged to resect tissue which may then be drawn into the extraction lumen, often via vacuum assistance through a cutting window. Most such electrosurgical tissue cutting devices rely on manually engaging the cutting window against the target tissue to be resected. While such manual engagement is often sufficient, in other cases, such as in laparoscopic procedures having limited access and field of view, the target tissue can be difficult to visualize prior to resection and, in particular, it can be difficult to assure that the optimum target site has been engaged by the cutting window. For these reasons, it would be desirable to provide improved electrosurgical cutting tools having improved visibility and ability engage and immobilize tissue prior to cutting and to extract the tissue from tools after cutting. 
         [0004]    Related patents and published applications include U.S. Pat. No. 8,221,404; U.S. Pat. No. 7,744,595; U.S. Pat. Publ. 2014/0336643; U.S. Pat. Publ. 2010/0305565; U.S. Pat. Publ. 2007/0213704; U.S. Pat. Publ. 2009/0270849; and U.S. Pat. Publ. 2013/0090642. 
       SUMMARY OF THE INVENTION 
       [0005]    In a first aspect of the present invention, a tissue resecting device comprises an elongated shaft having a central axis, a distal end, and an outer surface. An offset housing is mounted on the distal of the shaft and has a tissue-receiving window. The tissue-receiving window is offset radially outwardly from the outer surface of the shaft, and a moveable electrode is configured to move back and forth across the window to resect tissue which extends into the window. The offset housing improves visibility of the cutting window when viewed from endoscopes and other visualization apparatus. 
         [0006]    In specific embodiments, the tissue resecting device may be adapted to oscillate laterally across the window. For example, a motor may be coupled to the moveable electrode to oscillate the moveable electrode laterally across the window at a rate ranging from 1 Hz to 50 Hz. The tissue resecting device may further comprise a negative pressure source communicating with the window through the shaft, and a controller may be adapted to control at least one of an electrical source coupled to the electrode, the motor coupled to the moveable electrode, and the negative pressure source. The controller may be further adapted to control fluid inflows from a fluid source to a resection site. The window is usually offset outwardly from said outer shaft surface by at least 2 mm, often at least 4 mm, and typically in a range from 2 mm and 12 mm. 
         [0007]    In a second aspect of the present invention, a tissue resecting device comprises an elongated shaft extending about a central axis. A housing is attached to a distal end of the shaft and is positioned asymmetrically relative to the central axis. A moveable electrode configured to move in a back-and-forth stroke across a tissue-receiving window in the housing to resect tissue. The asymmetric housing improves visibility of the window and the ability of the moving electrode to resect tissue. 
         [0008]    In specific embodiments, the asymmetric housing has an L-shape relative to the central axis. In further embodiments, the window in the asymmetric housing is aligned in parallel to the central axis and extends radially outwardly from an outer surface of the shaft. The electrode is typically adapted to move laterally across the window but alternatively could be adapted to move axially across the window. The tissue resecting device may further comprise a motor coupled to the moveable electrode to oscillate the moveable electrode across the window, and the motor may be configured to oscillate the moveable electrode at a rate ranging from 1 Hz to 50 Hz. The electrode typically moves in an arc, and a surface of the window has will usually have an arc shape more usually an arc shape congruous with the arc of electrode travel. The window may have a rectangular shape, for example with an axial dimension ranging from 2 mm to 20 mm., and/or a lateral dimension ranging from 2 mm to 10 mm. The window may have circumferentially or axially spaced-apart edges, and the electrode may be configured to move past those edges. Alternatively, the window may have at least two sides with ledges for receiving the electrode at the termination of its stroke. 
         [0009]    In a third aspect of the present invention, a tissue resecting device comprises an elongated shaft extending within a cylindrical envelope. A distal end of the shaft is coupled to an offset housing having a tissue-receiving window. The window has a surface spaced radially outwardly from and oriented generally parallel to the cylindrical envelope. A moveable electrode is configured to move over the window surface and to resect tissue received through the window. As with previous aspects of the present invention, such structures improve visibility of the window and the ability of the moving electrode to resect tissue. 
         [0010]    In specific embodiments, the tissue resecting device further comprises a motor coupled to the moveable electrode to oscillate the moveable electrode across the window. The motor may be configured to oscillate the moveable electrode at a rate ranging from 1 Hz to 50 Hz. The window is typically offset radially outwardly from said outer shaft surface by at least 2 mm, often by at least 4 mm, and usually in a range from 2 mm to 12 mm. 
         [0011]    In a fourth aspect of the present invention, a tissue resecting device comprises an elongated shaft extending to a working end having a tissue-receiving window, said elongated shaft having an outer surface and said window having an exterior surface which is offset radially outwardly from the outer surface of the elongated shaft. A moveable electrode is configured to sweep across the exterior surface of the window. As with all prior aspects of the present invention described above, such structures improve visibility of the window and the ability of the moveable electrode to resect tissue. 
         [0012]    In specific embodiments, the tissue resecting device further comprises a motor coupled to the moveable electrode to oscillate the moveable electrode across the window. The motor may be configured to oscillate the moveable electrode at a rate ranging from 1 Hz to 50 Hz. The exterior surface of the window typically extends laterally in an arc, and the electrode portion moves in an arc over the exterior surface. The window may have a rectangular plan shape with an axial dimension ranging from 2 mm to 20 mm and a lateral dimension ranging from 2 mm to 10 mm. The electrode is typically configured to move past lateral edges of the window when being swept across the exterior surface of the window. Alternatively, the window may have at least two sides with ledges for receiving the electrode at the termination of its stroke. The window is preferably within a housing portion that is offset outwardly from an outer surface of the shaft. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a view of a tissue resecting device and a block diagram of systems and operating components corresponding to the invention. 
           [0014]      FIG. 2  is a perspective view of the working end of the resecting device of  FIG. 1  showing an asymmetric ceramic housing and moving electrode that is adapted to sweep across a tissue-receiving window. 
           [0015]      FIG. 3  is another perspective view of the working end of  FIG. 2  from a different angle. 
           [0016]      FIG. 4A  is a schematic view of the working end of  FIGS. 2-3  interfacing with tissue targeted for resection under endoscopic vision. 
           [0017]      FIG. 4B  is a schematic view of a working end of a prior art tubular cutting device used in a hypothetical resection procedure. 
           [0018]      FIG. 5  is another schematic view of the working end of  FIGS. 2-3  being used to resect targeted tissue to a significant depth from the organ surface. 
           [0019]      FIG. 6  is a perspective view of a distal dielectric housing of a working end similar to that of  FIGS. 2-3  showing window sides with ledges for receiving the electrode at the ends of its movement in a sweeping arc. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]      FIGS. 1  illustrates an electrosurgical tissue resecting system  100  for use in urological procedures to resect tissue that includes an introducer sleeve or sheath  102  and a hand-held single-use tissue resecting device or probe  105 . The resecting device  105  has a handle portion  108  that is coupled to an elongated shaft or extension portion  110  that has an outer diameter ranging from about 2 mm to 7 mm, and in one variation is 5 mm in diameter. The shaft  110  extends about longitudinal axis  112  to a working end  115  that is radially asymmetric relative the shaft  110  and its axis  112  as further described below. In one variation, the device is adapted for performing a TURP procedure (transurethral resection of prostate) or a bladder tumor resection procedure and thus the shaft portion  110  extends about axis  112  with a length suitable for introducing in a transurethral approach to reach the targeted prostate tissue or bladder tissue. 
         [0021]    As will be described below and shown in  FIG. 1 , the resecting device  105  is adapted for introduction through the introducer sleeve  102 . Such an introducer sleeve  102  is adapted to receive a commercially available endoscope  130  as can be understood from  FIG. 1 . 
         [0022]    Referring to  FIGS. 1-3 , in general, it can be seen the resecting device  105  has an elongated shaft  110  that extends to a distal shaft portion  132  that is coupled to an offset resecting housing  140  that has an offset tissue-receiving window  144 . A moveable electrode  145  is adapted to be driven by a motor drive unit  148  in handle  108  (see  FIG. 1 ) so that the longitudinal portion  149  of the electrode  145  sweeps across the window  144  from side to side to electrosurgically resect tissue that is captured in the window  144 . The targeted tissue can be suctioned into and captured in window  144  by means of a negative pressure source or outflow pump  150  in controller  155  that communicates with a tissue extraction channel  158  extending through the device  105  and terminating in the window  144 . 
         [0023]    More in particular, referring to  FIGS. 2 and 3 , the configuration of the offset housing  140  is adapted to perform multiple functions. First, the offset housing  140  positions the window surface WS (within curved plane P indicated in  FIG. 2 ) outwardly from the outer surface  160  of shaft  110  which then allows the window surface WS to be fully visible through a endoscope  130  or other viewing means that would be introduced parallel to the device shaft  110  (see  FIG. 4A ). For example,  FIG. 4A  is a schematic view of the working end  115  with working surface WS in contact with targeted tissue T. As can be seen in  FIG. 4A , the endoscope  130  is positioned with the field of view FV directly aligned with the working surface WS thus allowing optimal viewing of the tissue resection process. The outer surface  160  typically defines a cylindrical envelope from which the offset housing  140  projects radially. 
         [0024]    In contrast,  FIG. 4B  shows a working end  115 ′ of a conventional dual sleeve tubular cutter having a window surface WS′ which when pressed against an organ prevents endoscopic vision of the interface between the tubular cutting edge and the tissue T during a resection procedure. 
         [0025]    Second, the offset housing  140  is adapted for resecting tissue to a greater depth in a localized region of an organ, rather than resecting surface tissues over a broad area. More in particular as shown in  FIG. 5 , the offset portion  170  of housing  140  can be pushed into tissue perpendicular to axis  112  of the probe shaft  110 . Thus, as shown in  FIG. 5 , the offset housing  140  can be used to resect tissue deep into in a localized region that would not be possible with a resecting device having the configuration shown in  FIG. 4B . 
         [0026]      FIGS. 2 and 3  illustrate the asymmetric or offset dielectric housing  140  that can comprise a ceramic material such as zirconium oxide, aluminum oxide or similar materials as is known in the art. In  FIGS. 2-3 , it can be seen that window surface WS is offset from the shaft outersurface  160  by a predetermined dimension D which can be from 2 mm to 8 mm and in one embodiment comprises a 5 mm offset. 
         [0027]    As can be further be seen in  FIGS. 2-3 , the width W of the window surface WS around at least portions of the perimeter of the window  144  is a limited dimension, for example less than 3 mm, or less than 2 mm or less than 1 mm. which allows the offset portion  170  of housing  140  to be pushed into tissue perpendicular to the device axis  112  as the electrode  145  sweeps across the window  144 . 
         [0028]    Referring to  FIGS. 2-3 , one variation of resecting device  105  has an electrode  145  that can be tungsten or stainless steel wire that with electrode portion  149  adapted to sweep across the window  144  at any suitable rate, for example from 1 Hz to 500 Hz. In  FIG. 3 , it can be understood that the electrode  145  has an elongated proximal shaft portion  176  that extends into handle  108  of the device ( FIG. 1 ). The proximal end of electrode  145  is operatively coupled to a motor drive unit  148  and a suitable mechanism or controller is provided to move the elongated electrode proximal shaft portion  176  in an arc to resect tissue. 
         [0029]    As can be understood from  FIGS. 2-3 , the electrode portion  149  moves back and forth akin to a windshield wiper across window  144  in the offset housing  140 . A number of mechanisms can be used to effectuate the desired movements of the electrode, or the motor drive  148  simply can be controlled by software to move in intermittent clockwise and counter-clockwise directions. In one variation, the elongated electrode proximal shaft portion  176  of the electrode  145  will twist over its length and thus the motor drive  148  can be adapted to rotate the electrode shaft in an arc with radial angle which is greater than the window&#39;s comparable radial angle or arc. Thus, the electrode portion  149  can be expected to move back and forth entirely across the window even when meeting some tissue resistance by compensating for some twisting that is allowed in the elongated electrode proximal shaft portion  176 . In one variation, the motor drive unit can be adapted to over-rotate the electrode shaft portion  176  at its proximal end by a selected amount which can be from 10° radial motion to 90° radial motion to compensate for twisting of the electrode shaft portion to insure that electrode portion  149  sweeps entirely across the surface of window  144 . 
         [0030]    In general, the window  144  in housing  140  can be configured to have a radial arc relative to the electrode shaft  176  ranging between 30° and 180°. In one variation of housing  140 ′ shown in  FIG. 6 , it can be seen that the electrode portion  149  has a range of motion that extends across the radial dimension of the window  144  to ensure that any tissue captured in the window is resected as the electrode portion  149  passes the window edges  182   a  and  182   b  to function like a shear or in a scissor-like manner. The electrode portion  149  moves over ledges  186   a  and  186   b  on either side of the housing  140 ′ and can bump into surfaces  190   a  and  190   b.  By bumping into the surfaces  190   a  and  190   b,  any over rotation in the electrode shaft  176  to accommodate twisting as described above can limit the rotation of the electrode portion in the housing  140 ′. Further, in  FIG. 6 , it can be seen that the distal tip  192  of electrode portion  149  extends distally beyond window  144  and onto distal ledge  194  in the housing  140 ′ to ensure tissue is resected by the electrode in the distal window region. 
         [0031]    Now turning back to  FIG. 1 , it can be understood that the resecting device  105  and endoscope  130  can be used with introducer sleeve assembly or sheath  102 . As shown in  FIG. 1 , the introducer sleeve  102  has a proximal handle body  202  with a connector  204  that is adapted to couple to connector member  205 . The connector  205  is adapted to couple to controller  155  and provide within a single cable a first lumen communicating with the fluid outflow pump  150 , a second lumen communicating with a fluid inflow pump  225 , and a third lumen communicating with a pressure sensor positioned in the controller  155  or in or near the connector  205 . As can be seen in  FIG. 1 , the introducer sleeve  102  can also accommodate an endoscope  130 . Thus, the introducer sleeve  120  can be assembled with the endoscope  130  (and without the reaction device  105 ) and coupled by connector  205  to the controller  155  to provide an inflow of irrigation fluid from fluid source  226 , and outflow of irrigation fluid to collection reservoir  228  together with pressure sensing to allow the assembly to be used in a diagnostic procedure prior to a tissue resection procedure. In other words, the introducer sleeve  102  can function as a ‘continuous flow’ optical introducer for use in trans-urethral access to a targeted sire in the prostate or bladder. 
         [0032]    After the introducer sleeve assembly  102  is used for an initial diagnostic procedure, the endoscope  130  can be removed from the assembly  102  and connector  205  can be disconnected from handle body  205 . Thereafter, the sleeve portion  240  (see  FIG. 1 ) of introducer assembly  102  can be detached from proximal handle body  204  with the sleeve portion  240  remaining in the patient. Next, the endoscope  130  and connector  205  can be assembled with the resecting device  105  and the physician cam insert the resecting device  105  through the sleeve portion  240  remaining in the patient to access the targeted site. The resecting device  105  and sleeve portion  204  in combination then provide lumens as described above for fluid inflows, fluid outflows and direct pressure sensing through lumens in connector  205 . 
         [0033]    In another variation, the introducer sleeve assembly  102  can include a removable blunt tip obturator that can assist in atraumatic insertion in a patient&#39;s urethra. 
         [0034]    Referring to  FIGS. 2-3 , one variation of the resecting device as described above has an electrode  145  with a resecting portion  149  that moves radially in an arc relative to axis  112  and a distal window  144 . Another variation can provide an electrode  145  that reciprocates axially to move across the window  144  and would have similar effectiveness. 
         [0035]    Referring back to  FIG. 1 , the electrode  145  comprises a first polarity electrode or active electrode and the shaft portion indicates that  245  comprise the return electrode. 
         [0036]    Referring to  FIG. 1 , the resecting device  105  can be actuated by moveable finger grip  260  which is adapted to be squeezed toward fixed finger grip  262  to thus move the working end  115  and window surface WS axially back and forth to resect tissue. The physician can activate the electrosurgical function with a foot switch  265  ( FIG. 1 ) and then reciprocate the working end  115  back and forth from about 5 mm to 25 mm to resect tissue in a path. At the same time, the physician can slightly rotate the shaft of the resecting device  105  so that the window surface WS engages a wider path in the targeted tissue surface. 
         [0037]    In typical use, the physician would stabilize the sleeve portion  240  and endoscope  130 , and then reciprocate and slightly rotate the resecting device  105  during a tissue resection procedure. During such a procedure, the physician can also slightly rotate the sleeve  240  and endoscope  130  to optimize viewing of the targeted tissue.