Patent Publication Number: US-2019192180-A1

Title: Arthroscopic devices and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional application 62/610,872 (Attorney Docket No. 41879-737.101), filed on Dec. 27, 2018, the full disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a medical system that includes variations of motor-driven tubular cutter or arthroscopic shavers that are configured for both mechanical cutting and electrosurgical cutting, ablation and coagulation procedures 
     In endoscopic and other surgical procedures including subacromial decompression, anterior cruciate ligament reconstruction involving notchplasty, and arthroscopic resection of the acromioclavicular joint, there is a need for cutting and removal of bone and soft tissue. Currently, surgeons use arthroscopic shavers and burrs having rotational cutting surfaces to remove hard tissue in such procedures. 
     To promote efficiency, endoscopic tool systems include a reusable handpiece and a selection of interchangeable tool probes having different working ends have been proposed. Such working ends may each have two or more functionalities, such as soft tissue removal and hard tissue resection, so such tools systems can provide dozens of specific functionalities, providing great flexibility. 
     While a significant advantage, the need for one tool system to accommodate such flexibility is a challenge. In particular, it is necessary that the handpiece and control unit for the system be provided with correct information on the identity of the tool probe that has been attached as well as the operational parameters of the tool probe during use. 
     It is therefore an object of the present invention to provide improved tissue treatment devices, systems, and methods for their use, such as improved arthroscopic tissue resection devices and systems wherein a motor-driven electrosurgical device is configured for cutting and removing both bone or soft tissue from a joint or other site. It is a further object invention to provide improved systems and methods for device identification, monitoring, and control, such as controlled operational stopping and starting of motor-driven components in default positions. At least some of these objectives will be met by the inventions described herein. 
     2. Description of the Background Art 
     Commonly owned U.S. patents having relevant disclosures include U.S. Pat. Nos. 6,413,256; 6,821,275; 6,890,332; 7,220,261; 7,744,595; 8,221,404; 8,323,280; 8,333,763; 9,204,918; 9,247,983; 9,277,954; 9,585,675; 9,592,085; 9,603,656; 9,855,675; 9,795,434; 2017 10,022,140; 10,028,767; and 10,052,149. 
     SUMMARY OF THE INVENTION 
     The present invention provides multi-functional tissue treatment devices capable of performing two, three, four, or more different treatment modalities without the need to exchange devices, device components, or to reconfigure the devices in any significant manner. The tissue treatment devices of present invention may be combined with radio frequency (RF) or other electrosurgical sources as well as with electric motor drives and controllers so that the tissue treatment devices can perform a variety of tissue cutting, resecting, coagulation, and other mechanical and electrosurgical procedures by selectively driving and powering the device components and delivering RF for other electrical energy to electrodes and other energy delivery components of the devices. In this way, the number of individual devices needed to perform a surgical intervention can be reduced. 
     In a first aspect of the present invention, a tissue treatment device, such as an arthroscopic, laparoscopic, or other surgical tool, comprises a shaft assembly which includes an outer sleeve and an inner sleeve co-axially and rotatably received in an axial passage way of the outer sleeve. A dielectric housing has an outer cutting window which forms a distal portion of the outer sleeve, typically being a ceramic shell or enclosure having a hollow interior with a window in a wall of the housing. The ceramic housing may be attached to a metal or tube which forms a proximate portion of the outer sleeve. A distal portion of the inner sleeve forms an RF electrode and includes an inner cutting window formed therein, typically formed through a cylindrical wall of the distal region of the inner sleeve. Typically, but not necessarily, the inner sleeve may be formed from a metal or other electrically conductive material thus forming the electrode. The inner and outer cutting windows have inner and outer cutting edges which are disposed to close together, typically to pass each other in a shearing motion, as the inner sleeve is rotated relative to the outer sleeve. 
     The outer and inner cutting windows will be axially positioned so that they will radially align with one another as the inner sleeve is rotated relative to the outer sleeve. Thus, the inner sleeve may be rotated to a window-open position where the inner window and the outer window are aligned so that tissue may pass or be drawn into the opening formed as the windows are aligned. As the inner sleeve is further rotated about its axis, the inner cutting window will pass out of alignment with the outer cutting window until the inner and outer sleeves reach a window-closed configuration where a wall portion of the outer sleeve covers the inner cutting window and the inner sleeve. When the inner sleeve is in such window-closed configuration, a closed lower portion of the inner sleeve will be positioned within the outer cutting window and will be exposed for use as an electrode for electrosurgical coagulation or other purposes as explained more fully below. 
     The dialectic material of the dialectic housing typically comprises at least one of a ceramic, a glass, a polymer, or the like. In particular instances, the dialectic comprises a ceramic selected from the group consisting of alumina, zirconia, silicon nitride, yttria-stabilized zirconia, magnesia-stabilized zirconia, ceria-stabilized zirconia and zirconia toughened alumina. 
     Tissue treatment devices according to the present invention may be formed into systems which further comprise a motor (optionally in a removable handle) configured to selectively rotate the inner sleeve in the first and second rotational directions as well as a RF source configured to couple to the RF electrode. Such systems may further comprise a controller (optionally combined with the RF source in a control box) operably coupled to the motor and to the RF source. Using the motor, RF source, and controller, the inner sleeve can be rotated to at least its window-closed position wherein the inner window is covered by a wall of the dialectic housing and then to its window-open position when the inner window is aligned with the outer window in the dialectic housing. By continuously rotating the inner shaft relative to the outer sleeve, tissue drawn in through the aligned inner and outer cutting windows may be sheared and drawn into an interior passageway of the inner sleeve where it can optionally be withdrawn by a negative pressure applied to a proximal location along the passageway. In such instances, the controller will typically be configured to stop the motor to position the inner sleeve in at least one of the window-open and the window-closed position. 
     In specific instances, the controller will be configured to selectively operate the motor and the RF source in at least one of a first mode, a second mode, a third mode, and a fourth mode. In the first mode, the controller operates the motor to rotate or oscillate the inner sleeve without energizing the RF source in order to mechanically cut tissue without RF or other electrosurgical enhancement. In the second mode, the controller operates the motor to rotate or oscillate the inner sleeve and further energizes the RF source for cutting tissue with electrosurgical enhancement. In the third mode, the controller energizes the RF source while the inner sleeve remains stationary in the window-closed position. In this way, the treatment device can be used to apply a coagulative or a blade of energy to tissue through the RF electrode. In the fourth mode, the controller energizes the RF source while the inner sleeve is stationary in the window-open position to apply a coagulative or a blade of energy to tissue. 
     In a second aspect of the present invention, a tissue resecting system comprises a shaft assembly including an elongated outer sleeve with a distal ceramic portion having a resecting window that opens to a bore or passageway therein. An inner sleeve with a distal portion having an inner resecting window and being adapted to rotate in the bore through window-open and window-closed positions is able to thereby resect tissue and engaged by the resecting windows. The distal portion of the inner sleeve is at least partially electrically conductive to form an RF electrode. 
     Such tissue resecting systems may further comprise a motor configured to rotatably drive the inner sleeve relative to the outer sleeve. The system may still further comprise an RF source connected to the RF electrode. In still further embodiments, a negative pressure source may be provided and adapted to connect to a proximal end of the bore in order to draw a resected tissue through the shaft and away from the treatment region. Controllers may be provided to control the operating parameters of the motor, the RF source, and the negative pressure source. Typically, the systems further comprise a hub attached to a proximal end of the shaft assembly, where the hub is configured for detachably coupling to a handle which carries the drive motor. The inner sleeve may optionally have an opening in the surface opposed to the inner resecting window in order to allow fluid flow air through during these periods. 
     In a third aspect of the present invention, a method for treating tissue in a patient comprises engaging a distal end of the shaft of a tissue treatment device against a target tissue. The tissue treatment device is connected to a drive motor, and the target tissue is typically submerged in an electrically conductive fluid. The method comprises performing at least two of the following three tissue treatment operations. The first treatment operation comprises operating the drive motor to rotator oscillate an inner sleeve of the shaft without energizing the RF source to rotate an inner cutting window on the inner sleeve to mechanically cut tissue at the target tissue. The second treatment operation comprises operating the driving motor to rotate or oscillate the inner sleeve to in turn rotate or oscillate the inner cutting window on the inner sleeve and energizing the RF source to deliver a cutting current for electrosurgically cutting tissue at the targettissue. The third treatment operation comprises energizing the RF source to deliver a coagulation current to target tissue through a RF electrode on the inner sleeve while the inner sleeve is stationary. 
     In specific aspects, the methods of the present invention may further comprise sequentially performing all three of the three treatment operations. Further, the inner sleeve of the shaft may be rotated or oscillated relative to an outer shaft having an outer cutting window so that the inner and outer cutting windows rotate or oscillate past each other to mechanically shear tissue extending through the windows when the windows are aligned without energizing the RF source. Still further, the inner sleeve of the shaft may be rotated or oscillated relative to an outer shaft having an outer cutting window so that the inner and outer cutting windows rotate or oscillate past each other to electrosurgically cut tissue extending through the windows when the windows are aligned while energizing the RF source to apply a cutting current. Still further, the methods may comprise actuating a negative pressure source in communication with a passageway in the inner sleeve to aspirate conductive fluid and tissue to breath from the target sight as well as growing tissue through the aligned cutting windows to enhance tissue cutting, both mechanical and electrosurgical. 
     In other specific aspects, the present invention may be defined in the following numbered clauses: 
     Clause 1. A tissue resecting device for use in a conductive fluid, comprising:
         a tubular cutter comprising an outer sleeve and a co-axial inner sleeve, wherein a distal end of the outer sleeve comprises a dielectric housing with an outer resecting window therein and a distal end of the inner sleeve comprises and RF electrode with an inner resecting window therein;   a motor configured to rotatably drive the inner sleeve relative to the outer sleeve through window-open and window-closed positions to thereby resect tissue engaged by the resecting windows; and   an RF source operatively coupled to the RF electrode;   wherein the outwardly exposed RF electrode surface in the window-closed is adapted to cooperate with the RF source to allow ignition of a plasma about said RF electrode surface when submerged in conductive fluid.   wherein the inner sleeve in the window-closed position defines an outwardly exposed RF electrode surface area adapted to cooperate with the RF source to allow ignition of a plasma about said RF electrode surface area when submerged in conductive fluid.       

     Clause 2. The tissue resecting device of clause 1 wherein said RF electrode surface has an area of less than 15 mm 2 , less than 10 mm 2  or less than 8 mm 2 . 
     Clause 3. The tissue resecting device of clause 1 wherein said RF electrode surface has an area of less than 15 mm 2  and the RF source provides an average power of at least 100 W× 
     Clause 4. The tissue resecting device of clause 1 further comprising a negative pressure source coupled to a passageway in the inner sleeve communicating with the inner resecting window. 
     Clause 5. The tissue resecting device of clause 1 further comprising a controller configured to control operating parameters of the motor, the RF source and the negative pressure source. 
     Clause 6. The tissue treatment device of clause 5 wherein the controller includes an algorithm for stopping rotation of the inner sleeve in the window-closed position. 
     Clause 7. The tissue treatment device of clause 5 wherein the controller includes an algorithm for a second mode of operation in which the motor rotates or oscillates the inner sleeve with the RF electrode energized for electrosurgically cutting tissue. 
     Clause 8. The tissue treatment device of clause 5 wherein the controller includes an algorithm for a third mode of operation in which the inner sleeve is stationary and the RF electrode is energized for applying coagulative or ablative energy to tissue. 
     Clause 9. A tissue treatment device, comprising:
         a shaft assembly having an outer sleeve and a moveable co-axial inner sleeve, wherein the outer sleeve has a cutting window therein that cooperates with shearing edges of the inner sleeve;   wherein the distal portion of the outer sleeve that carries the cutting window comprises a dielectric housing; and   wherein the distal portion of the inner sleeve that carries the shearing edges comprises an RF electrode.       

     Clause 10. The tissue treatment device of clause 9 wherein inner sleeve is coupled to a motor drive. 
     Clause 11. The tissue treatment device of clause 9 wherein the motor drive is adapted to rotates the inner sleeve. 
     Clause 12. The tissue treatment device of clause 9 wherein the motor drive is adapted to reciprocate the inner sleeve. 
     Clause 13. The tissue treatment device of clause 9 wherein the motor drive is adapted to rotate and reciprocate the inner sleeve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the present invention will now be discussed with reference to the appended drawings. It should be appreciated that the drawings depict only typical embodiments of the invention and are therefore not to be considered limiting in scope. 
         FIG. 1  is a perspective view of an arthroscopic cutting system that includes reusable handpiece with a motor drive and a detachable single-use cutting probe, wherein the cutting probe is shown in two orientations as it may be coupled to the handpiece with the probe and working end in upward orientation or a downward orientation relative to the handpiece, and wherein the handpiece includes an LCD screen for displaying operating parameters of system during use together with control actuators on the handpiece. 
         FIG. 2A  is an enlarged longitudinal sectional view of the hub of the probe of  FIG. 1  taken along line  2 A- 2 A of  FIG. 1  with the hub and probe in an upward orientation relative to the handpiece, further showing Hall effect sensors carried by the handpiece and a plurality of magnets carried by the probe hub for device identification, for probe orientation and determining the position of motor driven components of the probe relative to the handpiece. 
         FIG. 2B  is a sectional view of the hub of  FIG. 1  taken along line  2 B- 2 B of  FIG. 1  with the hub and probe in a downward orientation relative to the handpiece showing the Hall effect sensor and magnets having a different orientation compared to that of  FIG. 2A . 
         FIG. 3A  is an enlarged perspective view of the working end of the probe of  FIG. 1  in an upward orientation with the rotatable cutting member in a first position relative to the outer sleeve wherein the window in the cutting member is aligned with the window of the outer sleeve. 
         FIG. 3B  is a perspective view of the working end of  FIG. 1  in an upward orientation with the rotatable cutting member in a second position relative to the outer sleeve wherein the electrode carried by the cutting member is aligned with a centerline of the window of the outer sleeve. 
         FIG. 4  is a perspective view of a working end of a variation of a probe that may be detachably coupled to the handpiece of  FIG. 1 , wherein the working end includes a bone burr extending distally from the outer sleeve. 
         FIG. 5  is a perspective view of a working end of a variation of a probe that may be detachably coupled to the handpiece of  FIG. 1 , wherein the working end has a reciprocating electrode. 
         FIG. 6  is a perspective view of a working end of another variation of a probe that may be detachably coupled to the handpiece of  FIG. 1 , wherein the working end has a hook electrode that has extended and non-extended positions. 
         FIG. 7  is a perspective view of a working end of yet another variation of a probe that may be detachably coupled to the handpiece of  FIG. 1 , wherein the working end has an openable-closeable jaw structure for cutting tissue. 
         FIG. 8  is a chart relating to set speeds for a probe with a rotating cutting member as in  FIGS. 1 and 3A  that schematically shows the method used by a controller algorithm for stopping rotation of the cutting member in a selected default position. 
         FIG. 9A  is a longitudinal sectional view of a probe hub that is similar to that of  FIG. 2A , except the hub of  FIG. 9A  has an internal cam mechanism for converting rotational motion to linear motion to axially reciprocate an electrode as in the working end of  FIG. 5 , wherein  FIG. 9A  illustrated the magnets in the hub and drive coupling are the same as in  FIG. 2A  and the hub is in an upward facing position relative to the handpiece. 
         FIG. 9B  is a sectional view of the hub of  FIG. 9A  rotated 180° in a downward facing position relative to the handpiece. 
         FIG. 10  is a perspective view of another variation of a probe that shows a motor-driven, rotating inner cutting sleeve that comprises an electrode and outer sleeve carrying a distal dielectric housing. 
         FIG. 10A  is an enlarged view of the electrode and outer sleeve carrying a distal dielectric housing of  FIG. 10  taken along line  10 A- 10 A. 
         FIG. 11A  is perspective view of the working end of the outer sleeve of the probe of  FIG. 10  separated from the inner sleeve. 
         FIG. 11B  is perspective view of the working end of the inner sleeve of the probe of  FIG. 10  with the inner sleeve window facing upward. 
         FIG. 11C  is perspective view of the working end of the inner sleeve of  FIG. 11B  with the inner sleeve window facing downward. 
         FIG. 12  is perspective view of the dielectric housing of  FIG. 11A . 
         FIG. 13  is a sectional view of the working end of  FIG. 10  taken along line  13 - 13  of  FIG. 10 . 
         FIG. 14  illustrates an alternative working end. 
         FIG. 15  is a perspective view of a working end of a motor-driven, rotating inner sleeve similar to that of  FIGS. 11B-11C  with abrasive cutting features for abrading bone. 
         FIG. 16  is a perspective view of a working end of another variation of a probe that shows a motor-driven, reciprocating inner sleeve comprising an electrode that reciprocates in a dielectric housing carried by the outer sleeve. 
         FIG. 17  is a perspective view of a working end of another variation of a probe that shows a reciprocating inner sleeve with a ceramic or glass cutting edge surrounding an electrode sleeve that reciprocates in a metal outer sleeve. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to bone cutting and tissue removal devices and related methods of use. Several variations of the invention will now be described to provide an overall understanding of the principles of the form, function and methods of use of the devices disclosed herein. In general, the present disclosure provides for variations of arthroscopic tools adapted for cutting bone, soft tissue, meniscal tissue, and for RF ablation and coagulation. The arthroscopic tools are typically disposable and are configured for detachable coupling to a non-disposable handpiece that carries a motor drive component. This description of the general principles of this invention is not meant to limit the inventive concepts in the appended claims. 
     In one variation shown in  FIG. 1 , the arthroscopic system  100  of the present invention provides a handpiece  104  with motor drive  105  and a disposable shaver assembly or probe  110  with a proximal hub  120  that can be received by receiver or bore  122  in the handpiece  104 . In one aspect, the probe  110  has a working end  112  that carries a high-speed rotating cutter that is configured for use in many arthroscopic surgical applications, including but not limited to treating bone in shoulders, knees, hips, wrists, ankles and the spine. 
     In  FIGS. 1, 2A and 3A , it can be seen that probe  110  has a shaft  125  extending along longitudinal axis  128  that comprises an outer sleeve  140  and an inner sleeve  142  rotatably disposed therein with the inner sleeve  142  carrying a distal ceramic cutting member  145  ( FIG. 3A ). The shaft  125  extends from the proximal hub  120  wherein the outer sleeve  140  is coupled in a fixed manner to the hub  120  which can be an injection molded plastic, for example, with the outer sleeve  140  insert molded therein. The inner sleeve  142  is coupled drive coupling  150  that is configured for coupling to the rotating motor shaft  151  of motor drive unit  105 . More in particular, the rotatable cutting member  145  that is fabricated of a ceramic material with sharp cutting edges on opposing sides  152   a  and  152   b  of window  154  therein for cutting soft tissue. The motor drive  105  is operatively coupled to the ceramic cutter to rotate the cutting member at speeds ranging from 1,000 rpm to 20,000 rpm. In  FIG. 3B , it can be seen that cutting member  145  also carries an RF electrode  155  in a surface opposing the window  154 . The cutting member  145  rotates and shears tissue in the toothed opening or window  158  in the outer sleeve  140  ( FIG. 3A ). A probe of the type shown in  FIG. 1  is described in more detail in co-pending and commonly owned patent application Ser. No. 15/421,264 filed Jan. 31, 2017 (Atty. Docket 41879-714.201) titled ARTHROSCOPIC DEVICES AND METHODS which is incorporated herein in its entirety by this reference. 
     As can be seen in  FIG. 1 , the probe  110  is shown in two orientations for detachable coupling to the handpiece  104 . More particularly, the hub  120  can be coupled to the handpiece  104  in an upward orientation indicated at UP and a downward orientation indicated at DN where the orientations are 180° opposed from one another. It can be understood that the upward and downward orientations are necessary to orient the working end  112  either upward or downward relative to the handpiece  104  to allow the physician to interface the cutting member  145  with targeted tissue in all directions without having to manipulate the handpiece in 360° to access tissue. 
     In  FIG. 1 , it can be seen that the handle  104  is operatively coupled by electrical cable  160  to a controller  165  which controls the motor drive unit  105  Actuator buttons  166   a ,  166   b  or  166   c  on the handle  104  can be used to select operating modes, such as various rotational modes for the ceramic cutting member  145 . In one variation, a joystick  168  can be moved forward and backward to adjust the rotational speed of the ceramic cutting member  145 . The rotational speed of the cutter can continuously adjustable, or can be adjusted in increments up to 20,000 rpm. An LCD screen  170  is provided in the handpiece for displaying operating parameters, such as cutting member RPM, mode of operation, etc. 
     It can be understood from  FIG. 1  that the system  100  and handpiece  104  is adapted for use with various disposable probes which can be designed for various different functions and procedures For example,  FIG. 4  illustrates a different variation of a probe working end  200 A that is similar to working end  112  of probe  110  of  FIGS. 3A-3B , except the ceramic cutting member  205  extends distally from the outer sleeve  206  and the cutting member has burr edges  208  for cutting bone. The probe of  FIG. 4  is described in more detail in co-pending and commonly owned patent application Ser. No. 15/271,184 filed Sep. 20, 2016 (Atty. Docket 41879-728.201) titled ARTHROSCOPIC DEVICES AND METHODS.  FIG. 5  illustrates a different variation of a probe working end  200 B with a reciprocating electrode  210  in a type of probe described in more detail in co-pending and commonly owned patent application Ser. No. 15/410,723 filed Jan. 19, 2017 (Atty. Docket 41879-713.201) titled ARTHROSCOPIC DEVICES AND METHODS. In another example,  FIG. 6  illustrates another variation of a probe working end  200 C that has an extendable-retractable hook electrode  212  in a probe type described in more detail in co-pending and commonly owned patent application Ser. No. 15/454,342 filed Mar. 9, 2017 (Atty. Docket 41879-715.201) titled ARTHROSCOPIC DEVICES AND METHODS. In yet another example,  FIG. 7  illustrates a variation of a working end  200 D in a probe type having an openable-closable jaw structure  215  actuated by reciprocating member  218  for trimming meniscal tissue or other tissue as described in more detail in co-pending and commonly owned patent application Ser. No. 15/483,940 filed Apr. 10, 2017 (Atty. Docket 41879-721.201) titled ARTHROSCOPIC DEVICES AND METHODS. All of the probes of  FIGS. 4-7  can have a hub similar to hub  120  of probe  110  of  FIG. 1  for coupling to the same handpiece  104  of  FIG. 1 , with some of the probes (see  FIGS. 5-7 ) having a hub mechanism for converting rotational motion to linear motion. All of the patent applications just identified in this paragraph are incorporated herein by this reference. 
       FIG. 1  further shows that the system  100  also includes a negative pressure source  220  coupled to aspiration tubing  222  which communicates with a flow channel  224  in handpiece  104  and can cooperate with any of the probes  110 ,  200 A,  200 B or  200 C of  FIGS. 1-3B, 4, 5 and 6 . In  FIG. 1  it also can be seen that the system  100  includes an RF source  225  which can be connected to an electrode arrangement in any of the probes  110 ,  200 A,  200 B or  200 C of  FIGS. 1-3B, 4, 5 and 6 . The controller  165  and microprocessor therein together with control algorithms are provided to operate and control all functionality, which includes controlling the motor drive  105  to move a motor-driven component of any probe working end  110 ,  200 A,  200 B or  200 C, as well as for controlling the RF source  225  and the negative pressure source  220  which can aspirate fluid and tissue debris to collection reservoir  230 . 
     As can be understood from the above description of the system  100  and handpiece  104 , the controller  165  and controller algorithms need to be configured to perform and automate many tasks to provide for system functionality. In a first aspect, controller algorithms are needed for device identification so that when any of the different probes types  110 ,  200 A,  200 B,  200 C or  200 D of  FIGS. 1 and 4-7  are coupled to handpiece  104 , the controller  165  will recognize the probe type and then select algorithms for operating the motor drive  105 , RF source  225  and negative pressure source  220  as is needed for the particular probe. In a second aspect, the controller is configured with algorithms that identify whether the probe is coupled to the handpiece  104  in an upward or downward orientation relative to the handpiece, wherein each orientation requires a different subset of the operating algorithms. In another aspect, the controller has separate control algorithms for each probe type wherein some probes have a rotatable cutter while others have a reciprocating electrode or jaw structure. In another aspect, most if not all the probes  110 ,  200 A,  200 B,  200 C and  200 D ( FIGS. 1, 4-7 ) require a default “stop” position in which the motor-driven component is stopped in a particular orientation within the working end. For example, a rotatable cutter  145  with an electrode  155  needs to have the electrode centered within an outer sleeve window  158  in a default position such as depicted in  FIG. 3B . Some of these systems, algorithms and methods of use are described next. 
     Referring to  FIGS. 1 and 2A-2B , it can be seen that handpiece  104  carries a first Hall effect sensor  240  in a distal region of the handpiece  104  adjacent the receiving passageway  122  that receives the hub  120  of probe  110 .  FIG. 2A  corresponds to the probe  110  and working end  112  in  FIG. 1  being in the upward orientation indicated at UP.  FIG. 2B  corresponds to probe  110  and working end  112  in  FIG. 1  being in the downward orientation indicated at DN. The handpiece  104  carries a second Hall affect sensor  245  adjacent the rotatable drive coupling  150  of the probe  110 . The probe  110  carries a plurality of magnets as will be described below that interact with the Hall effect sensors  240 ,  245  to provide multiple control functions in cooperation with controller algorithms, including (i) identification of the type of probe coupled to the handpiece, (ii) the upward or downward orientation of the probe hub  120  relative to the handpiece  104 , and (iii) the rotational position and speed of rotating drive collar  150  from which a position of either rotating or reciprocating motor-driven components can be determined. 
     The sectional views of  FIGS. 2A-2B  show that hub  120  of probe  110  carries first and second magnets  250   a  and  250   b  in a surface portion thereof. The Hall sensor  240  in handpiece  104  is in axial alignment with either magnet  250   a  or  250   b  when the probe hub  120  is coupled to handpiece  104  in an upward orientation ( FIGS. 1 and 2A ) or a downward orientation ( FIGS. 1 and 2B ). In one aspect as outlined above, the combination of the magnets  250   a  and  250   b  and the Hall sensor  240  can be used to identify the probe type. For example, a product portfolio may have from 2 to 10 or more types of probes, such as depicted in  FIGS. 1 and 4-7 , and each such probe type can carry magnets  250   a ,  250   b  having a specific, different magnetic field strength. Then, the Hall sensor  240  and controller algorithms can be adapted to read the magnetic field strength of the particular magnet(s) in the probe which can be compared to a library of field strengths that correspond to particular probe types. Then, a Hall identification signal can be generated or otherwise provided to the controller  165  to select the controller algorithms for operating the identified probe, which can include parameters for operating the motor drive  105 , negative pressure source  220  and/or RF source  225  as may be required for the probe type. As can be seen in  FIGS. 1, 2A and 2B , the probe hub  120  can be coupled to handpiece  104  in upward and downward orientations, in which the North (N) and South (S) poles of the magnets  250   a ,  250   b  are reversed relative to the probe axis  128 . Therefore, the Hall sensor  240  and associated algorithms look for magnetic field strength regardless of polarity to identify the probe type. 
     Referring now to  FIGS. 1, 2A-2B and 3A-3B , the first and second magnets  250   a  and  250   b  with their different orientations of North (N) and South (S) poles relative to central longitudinal axis  128  of hub  120  are also used to identify the upward orientation UP or the downward orientation DN of hub  120  and working end  112 . In use, as described above, the physician may couple the probe  110  to the handpiece receiving passageway  122  with the working end  112  facing upward or downward based on his or her preference and the targeted tissue. It can be understood that controller algorithms adapted to stop rotation of the cutting member  145  in the window  158  of the outer sleeve  104  of working end  112  need to “learn” whether the working end is facing upward or downward, because the orientation or the rotating cutting member  145  relative to the handpiece and Hall sensor  240  would vary by 180°. The Hall sensor  240  together with a controller algorithm can determine the orientation UP or the downward orientation DN by sensing whether the North (N) or South (S) pole of either magnet  250   a  or  250   b  is facing upwardly and is proximate the Hall sensor  240 . 
     In another aspect of the invention, in probe  110  ( FIG. 1 ) and other probes, the motor-driven component of a working end, such as rotating cutter  145  of working end  112  of  FIGS. 1 and 3A-3B  needs to stopped in a selected rotational position relative to a cut-out opening or window  158  in the outer sleeve  140 . Other probe types may have a reciprocating member or a jaw structure as described above, which also needs a controller algorithm to stop movement of a moving component in a selected position, such as the axial-moving electrodes of  FIGS. 5-6  and the jaw structure of  FIG. 7 . In all probes, the motor drive  105  couples to the rotating drive coupling  150 , thus sensing the rotational position of the drive coupling  150  can be used to determine the orientation of the motor-driven component in the working end. More in particular, referring to  FIGS. 1 and 2A-2B , the drive coupling  150  carries third and fourth magnets  255   a  or  255   b  with the North (N) and South (S) poles of magnets  255   a  or  255   b  being reversed relative to the probe axis  128 . Thus, Hall sensor  245  can sense when each magnet rotates passes the Hall sensor and thereby determine the exact rotational position of the drive coupling  150  twice on each rotation thereof (once for each magnet  255   a ,  255   b ). Thereafter, a controller tachometer algorithm using a clock can determine and optionally display the RPM of the drive coupling  150  and, for example, the cutting member  145  of  FIG. 3A . 
     In another aspect of the invention, the Hall sensor  245  and magnets  255   a  and  255   b  ( FIGS. 1 and 2A ) are used in a set of controller algorithms to stop the rotation of a motor-driven component of a working end, for example, cutting member  145  of  FIGS. 1 and 3A-3B  in a pre-selected rotational position. In  FIG. 3A , it can be seen that the inner sleeve  142  and a “first side” of cutting member  145  and window  154  therein is stopped and positioned in the center of window  158  of outer sleeve  140 . The stationary position of cutting member  145  and window  154  in  FIG. 3A  may be used for irrigation or flushing of a working space to allow for maximum fluid outflow through the probe. 
       FIG. 3B  depicts inner sleeve  142  and a “second side” of cutting member  145  positioned about the centerline of window  158  in the outer sleeve  140 . The stationary or stopped position of cutting member  145  in  FIG. 3B  is needed for using the RF electrode  155  to ablate or coagulate tissue. It is important that the electrode  155  is maintained along the centerline of the outer sleeve window  158  since the outer sleeve  140  typically comprises return electrode  260 . The position of electrode  155  in  FIG. 3B  is termed herein a “centerline default position”. If the cutting member  145  and electrode  155  were rotated so as to be close to an edge  262   a  or  262   b  of window  158  in outer sleeve  140 , RF current could arc between the electrodes  155  and  260  and potentially cause a short circuit disabling the probe. Therefore, a robust and reliable stop mechanism is required which is described next. 
     As can be understood from  FIGS. 1 and 2A-2B , the controller  165  can always determine in real time the rotational position of drive coupling  150  and therefore the angular or rotational position of the ceramic cutting member  145  and electrode  155  can be determined. A controller algorithm can further calculate the rotational angle of the electrode  155  away from the centerline default position as the Hall sensor  245  can sense lessening of magnetic field strength as a magnet  255   a  or  255   b  in the drive coupling  150  rotates the electrode  155  away from the centerline default position. Each magnet has a specified, known strength and the algorithm can use a look-up table with that lists fields strengths corresponding to degrees of rotation away from the default position. Thus, if the Hall signal responsive to the rotated position of magnet  255   a  or  255   b  drops a specified amount from a known peak value in the centerline default position, it means the electrode  155  has moved away from the center of the window  158 . In one variation, if the electrode  155  moves a selected rotational angle away from the centerline position during RF energy delivery to the electrode, the algorithm turns off RF current instantly and alerts the physician by an aural and/or visual signal, such as an alert on the LCD screen  170  on handpiece  104  and/or on a screen on a controller console (not shown). The termination of RF current delivery thus prevents the potential of an electrical arc between electrode  155  and the outer sleeve electrode  260 . 
     It can be understood that during use, when the electrode  155  is in the position shown in  FIG. 3B , the physician may be moving the energized electrode over tissue to ablate or coagulate tissue. During such use, the cutting member  145  and electrode  155  can engage or catch on tissue which inadvertently rotate the electrode  155  out of the default centerline position. Therefore, the system provides a controller algorithm, herein called an “active electrode monitoring” algorithm, wherein the controller continuously monitors position signals generated by Hall sensor  245  during RF energy delivery in both an ablation mode and a coagulation mode to determine if the electrode  155  and inner sleeve  142  have been bumped off the centerline position. In a variation, the controller algorithms can be configured to then re-activate the motor drive  105  to move the inner sleeve  142  and electrode  155  back to the default centerline position sleeve if electrode  155  had been bumped off the centerline position. In another variation, the controller algorithms can be configured to again automatically deliver RF current to RF electrode  155  when it is moved back to the to the default centerline position. Alternatively, the controller  165  can require the physician to manually re-start the delivery of RF current to the RF electrode  155  when it is moved back to the to the centerline position. In an aspect of the invention, the drive coupling  150  and thus magnets  255   a  and  255   b  are attached to inner sleeve  142  and cutting member  145  in a pre-determined angular relationship relative to longitudinal axis  128  so that the Hall sensor generates signals responsive to magnets  255   a ,  255   b  is the same for all probes within a probe type to thus allow the controller algorithm to function properly. 
     Now turning to the stop mechanism or algorithms for stopping movement of a motor-driven component of working end  112 ,  FIG. 8  schematically illustrates the algorithm and steps of the stop mechanism. In one variation, referring to  FIG. 8 , the stop mechanism corresponding to the invention uses (i) a dynamic braking method and algorithm to stop the rotation of the inner sleeve  142  and cutting member  145  ( FIGS. 1, 3A-3B ) in an initial position, and thereafter (ii) a secondary checking algorithm is used to check the initial stop position that was attained with the dynamic braking algorithm, and if necessary, the stop algorithm can re-activate the motor drive  105  to slightly reverse (or move forward) the rotation of drive coupling  150  and inner sleeve  142  as needed to position the cutting member  145  and electrode  155  within at the centerline position or within 0° to 5° of the targeted centerline default position. Dynamic braking is described further below.  FIG. 8  schematically illustrates various aspects of controller algorithms for controlling the rotational speed of the cutting member and for stopping the cutting member  145  in the default centerline position. 
     In  FIG. 8 , it can be understood that the controller  165  is operating the probe  110  of  FIGS. 1 and 3A-3B  at a “set speed” which may be a PID controlled, continuous rotation mode in one direction or may be an oscillating mode where the motor drive  105  rotates the cutting member  145  in one direction and then reverses rotation as is known in the art. At higher rotational speeds such as 1,000 RPM to 20,000 RPM, it is not practical or feasible to acquire a signal from Hall sensor  245  that indicates the position of a magnet  255   a  or  255   b  in the drive coupling  150  to apply a stop algorithm. In  FIG. 8 , when the physician stop cutting with probe  110  by releasing actuation of an actuator button or foot pedal, current to the motor drive  105  is turned off. Thereafter, the controller algorithm uses the Hall sensor  245  to monitor deceleration of rotation of the drive coupling  150  and inner sleeve  142  until a slower RPM is reached. The deceleration period may be from 10 ms to 1 sec and typically is about 100 ms. When a suitable slower RPM is reached which is called a “search speed” herein (see  FIG. 8 ), the controller  165  re-activates the motor drive  105  to rotate the drive coupling at a low speed ranging from 10 RPM to 1,000 RPM and in one variation is between 50 RPM and 250 RPM. An initial “search delay” period ranging from 50 ms to 500 ms is provided to allow the PID controller to stabilize the RPM at the selected search speed. Thereafter, the controller algorithm monitors the Hall position signal of magnet strength and when the magnet parameter reaches a predetermined threshold, for example, when the rotational position of drive coupling  150  and electrode  155  correspond to the centerline default position of  FIG. 3B , the control algorithm then applies dynamic braking to instantly stop rotation of the motor drive shaft  151 , drive coupling  150  and the motor-driven component of the probe.  FIG. 8  further illustrates that the controller can check the magnet/drive coupling  150  position after the braking and stopping steps. If the Hall position signal indicates that the motor-driven component is out of the targeted default position, the motor drive  105  can be re-activated to move the motor-driven component and thereafter the brake can be applied again as described above. 
     Dynamic braking as shown schematically in  FIG. 8  may typically stop the rotation of the drive coupling  150  with a variance of up to about 0°-15° of the targeted stop position, but this can vary even further when different types of tissue are being cut and impeding rotation of the cutting member  145 , and also depending on whether the physician has completely disengaged the cutting member from the tissue interface when the motor drive is de-activated. Therefore, dynamic braking alone may not assure that the default or stop position is within a desired variance. 
     As background, the concept of dynamic braking is described in the following literature: https://www.ab.com/support/abdrives/documentation/techpapers/RegenOverview01.pdf and http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/drives-wp004_-en-p.pdf. Basically, a dynamic braking system provides a chopper transistor on the DC bus of the AC PWM drive that feeds a power resistor that transforms the regenerative electrical energy into heat energy. The heat energy is dissipated into the local environment. This process is generally called dynamic braking with the chopper transistor and related control and components called the chopper module and the power resistor called the dynamic brake resistor. The entire assembly of chopper module with dynamic brake resistor is sometimes referred to as the dynamic brake module. The dynamic brake resistor allows any magnetic energy stored in the parasitic inductance of that circuit to be safely dissipated during the turn off of the chopper transistor. 
     The method is called dynamic braking because the amount of braking torque that can be applied is dynamically changing as the load decelerates. In other words, the braking energy is a function of the kinetic energy in the spinning mass and as it declines, so does the braking capacity. So the faster it is spinning or the more inertia it has, the harder you can apply the brakes to it, but as it slows, you run into the law of diminishing returns and at some point, there is no longer any braking power left. 
     In another aspect of the invention, a method has been developed to increase the accuracy of the stopping mechanism which is a component of the positioning algorithm described above. It has been found that each magnet in a single-use probe may vary slightly from its specified strength. As described above, the positioning algorithm uses the Hall effect sensor  245  to continuously monitor the field strength of magnets  255   a  and  255   b  as the drive coupling  150  rotates and the algorithm determines the rotational position of the magnets and drive coupling based on the field strength, with the field strength rising and falling as a magnet rotates past the Hall sensor. Thus, it is important for the algorithm to have a library of fields strengths that accurately correspond to degrees of rotation away from a peak Hall signal when a magnet is adjacent the sensor  245 . For this reason, an initial step of the positioning algorithm includes a “learning” step that allow the controller to learn the actual field strength of the magnets  255   a  and  255   b  which may vary from the specified strength. After a new single-use probe  110  ( FIG. 1 ) is coupled to the handpiece  104 , and after actuation of the motor drive  105 , the positioning algorithm will rotate the drive coupling at least 180° and more often at least 360° while the Hall sensor  245  quantifies the field strength of the particular probe&#39;s magnets  255   a  and  255   b . The positioning algorithm then stores the maximum and minimum Hall signals (corresponding to North and South poles) and calibrates the library of field strengths that correspond to various degrees of rotation away from a Hall min-max signal position when a magnet is adjacent the Hall sensor. 
     In general, a method of use relating to the learning algorithm comprises providing a handpiece with a motor drive, a controller, and a probe with a proximal hub configured for detachable coupling to the handpiece, wherein the motor drive is configured to couple to a rotating drive coupling in the hub and wherein the drive coupling carries first and second magnets with North and South poles positioned differently relative to said axis, and coupling the hub to the handpiece, activating the motor drive to thereby rotate the drive coupling and magnets at least 180°, using a handpiece sensor to sense the strength of each magnet, and using the sensed strength of the magnets for calibration in a positioning algorithm that is responsive to the sensor sensing the varying strength of the magnets in the rotating drive coupling to thereby increase accuracy in calculating the rotational position of the drive coupling  150 . 
     Another aspect of the invention relates to an enhanced method of use using a probe working end with an electrode, such as the working end  112  of  FIGS. 1 and 3B . As described above, a positioning algorithm is used to stop rotation of the electrode  155  in the default centerline position of  FIG. 3B . An additional “slight oscillation” algorithm is used to activate the motor drive  105  contemporaneous with RF current to the electrode  155 , particularly an RF cutting waveform for tissues ablation. The slight oscillation thus provides for a form of oscillating RF ablation. The slight oscillation algorithm rotates the electrode  155  in one direction to a predetermined degree of rotation, which the controller algorithms determine from the Hall position signals. Then, the algorithm reverses direction of the motor drive to rotate in the opposite direction until Hall position signals indicate that the predetermined degree of rotation was achieved in the opposite direction away from the electrode&#39;s default centerline position. The predetermined degree of angular motion can be any suitable rotation that is suitable for dimensions of the outer sleeve window, and in one variation is from 1° to 30° in each direction away from the centerline default position. More often, the predetermined degree of angular motion is from 5° to 15° in each direction away from the centerline default. The slight oscillation algorithm can use any suitable PID controlled motor shaft speed, and in one variation the motor shaft speed is from 50 RPM to 5,000 RPM, and more often from 100 RPM to 1,000 RPM. Stated another way, the frequency of oscillation can be from 20 Hz to 2,000 Hz and typically between 40 Hz and 400 Hz. 
     While the above description of the slight oscillation algorithm is provided with reference to electrode  155  on a rotating cutting member  145  of  FIG. 3B , it should be appreciated that a reciprocating electrode  212  as shown in the working end  200 C of  FIG. 6  end could also be actuated with slight oscillation. In other words, the hook shape electrode  212  of  FIG. 6  could be provided with a frequency of oscillation ranging from 20 Hz to 2,000 Hz and typically between 40 Hz and 400 Hz. 
       FIGS. 9A-9B  are longitudinal sectional views of a probe hub  120 ′ that corresponds to the working end  200 B of  FIG. 5  which has a reciprocating electrode  210 . In  FIGS. 9A-9B , the handpiece  104  and Hall affect sensors  240  and  245  are of course the same as described above as there is no change in the handpiece  104  for different types of probes. The probe hub  120 ′ of  FIGS. 9A-9B  is very similar to the hub  120  of  FIGS. 2A-2B  with the first and second identification/orientation magnets  250   a  and  250   b  being the same. The third and fourth rotation al position magnets  255   a  and  255   b  also are the same and are carried by drive coupling  150 ′. The probe hub  120 ′ of  FIGS. 9A-9B  only differs in that the drive coupling  150  rotates with a cam mechanism operatively coupled to inner sleeve  142 ′ to convert rotational motion to linear motion to reciprocate the electrode  210  in working end  200 B of  FIG. 5 . A similar hub for converting rotational motion to linear motion is provided for the working ends  200 C and  200 D of  FIGS. 6 and 7 , respectively, which each have a reciprocating component ( 212 ,  218 ) in its working end. 
     Now turning to  FIGS. 10 and 11A-11C , another variation of an arthroscopic shaver or resection probe  400  is shown which somewhat similar to that of  FIGS. 1 and 3A-3B  which comprises a tubular cutter having a proximal hub  402  coupled to an elongated shaft assembly  405 . The shaft assembly comprises an outer sleeve  410  and a concentric inner sleeve  415  that extends along axis  418  to a working end  420 . The hub  402  again is adapted for coupling to a handpiece and motor drive operated by a controller and controller algorithms having the features as described in previous embodiments for rotating the inner sleeve  415  as well as stopping the inner sleeve  415  in a selected rotational position, such as a window-closed or window-open position. The working end  420  again has an outer sleeve window  422  (also referred to as the outer cutting or resection window) that cooperates with an inner sleeve window  425  for engaging and resecting tissue. 
     The variation in  FIGS. 10, 10A and 11A-11C , the shaft assembly  405  differs in that the outer sleeve  410  has a distal end portion that comprises a dielectric body or housing  440  in which the outer window  422  is disposed. In one variation, a proximal  426   a  and a medial portion  426   b  of the outer sleeve  410  extend from the hub  402  and comprise a thin-wall, electrically conductive metal tube  428 , such as a stainless steel tube. As will be described further below, the proximal and/or medial portions of the metal tube can function as an electrode, for example located at  430  in  FIG. 10 . In a typical variation, the dielectric housing  440  comprises a ceramic material, a glass material, a polymeric material or a combination thereof. In some variations, the dielectric housing  440  can be carried within a metal support portion  442  which extends distally from the metal outer tube  428  and is positioned underneath or partly surrounding a distal portion of the dielectric housing  440 . 
       FIG. 11A  shows a working end  436  of the outer sleeve  410  with the outer cutting or resecting window  422  separated from the inner sleeve  415 . It can be seen that an axial passageway or bore  444  extends through the outer sleeve  410  and the dielectric housing  440  in which the concentric inner sleeve  415  ( FIGS. 11B and 11C ) is co-axially and rotationally disposed. 
       FIGS. 11B and 11C  show a working end  438  of the inner sleeve  415  which extends through the passageway or bore  444  of the outer sleeve  410  of  FIG. 11A . The working end  438  is shown in a first position with the inner sleeve window  425  facing upwardly in  FIG. 11B .  FIG. 11C  illustrates the same inner sleeve  415  rotated 180° so that the inner sleeve window  425  is facing downwardly. The inner sleeve  415  comprises a thin-wall tube comprising a metal or other conductive material, such as stainless steel, which can function as an electrode indicated at  450  ( FIG. 11C ). The electrode  450  of working end  438  of the inner sleeve  415  is typically sized or otherwise configured to have a close rotational fit in the passage way or bore  444  of the dielectric housing  440  so that the inner window edges  456 , with optional teeth, and the edges  458  outer sleeve window and act like scissors for shearing or resecting tissue, either mechanically or electrosurgically, as will be described further below. Still referring to  FIGS. 11A and 11B , a proximal portion of the inner sleeve  415  is covered by a thin layer  470  of an insulating polymer, such as a heat shrink tubing or a parylene coating, to electrically insulate the outer surface of inner sleeve  415  from the inner surface of the metal outer sleeve  428 . 
     In another aspect of the invention, as can be seen in  FIGS. 10 and 11C , the back side  472  of the inner sleeve  415  which opposes the inner sleeve window  425  has at least one opening  475  that is provided for fluid outflows therethrough when the inner sleeve  415  is rotated relative to the outer sleeve  410  to a window-closed position (see  FIG. 1 ). 
       FIG. 12  illustrates the dielectric or ceramic housing or portion  440  with the outer sleeve  410  shown in phantom view. It can be seen that the dielectric housing  440  has a recessed portion  476  in which a distal end or extension  477  of outer sleeve  410  surrounds and supports the dielectric housing  440 . The thickness of a wall of the dielectric housing around the window  422  can range from about 0.05″ to 0.20″. 
       FIG. 13  is a longitudinal sectional view of the working end  420  of the probe of  FIGS. 10-11C  which shows the working end  420  in its window-closed position. It can be seen that the working end  438  of the inner sleeve  415  is in close tolerance with bore  444  in the dielectric housing  440  so that rotation of inner sleeve  415  can shear tissue protruding through the inner sleeve and outer sleeve windows  422 ,  425 .  FIG. 13  further illustrates how the support portion  442  of the metal outer sleeve  428  extends underneath the ceramic housing or portion  440 . In addition,  FIG. 13  also shows the thin insulating layer  470  that surrounds the inner sleeve  415  to electrically insulate the inner sleeve from the metal outer sleeve  428 . 
     Still referring to  FIG. 13 , an RF source  480  is coupled to both the inner sleeve  410  and the outer sleeve  415  to provide for electrosurgical functionality. The RF source  480  is capable of delivering an average of at least 100W, often at least 200W, more often at least 300W and frequently at least 400W to allow for ignition of a plasma over the exposed outward or exterior surface  482  of the inner sleeve  415  in the window-closed position as shown in  FIG. 10 . Typically, the outward surface  482  of the inner sleeve  415  in the window-closed position has an area less than 15 mm 2 , often less than 10 mm 2 , and frequently less than 8 mm 2 . Rotation of the inner sleeve  415  in the outer sleeve  410  in a first mode of operation can mechanically shear tissue protruding through the windows  422  and  425  while operation in a second mode can electrosurgically resect such tissue. That is, the inner sleeve can rotate and shear tissue while the RF source  480  contemporaneously delivers the cutting current to the inner sleeve to energize the edges of the inner sleeve window  425  which can create a plasma to shear tissue or to assist in shearing tissue. 
     In general, a resecting probe or treatment device corresponding to the invention comprises shaft assembly  405  having an outer sleeve  410  and a rotatable inner sleeve  415  co-axially received in a bore  444  in outer sleeve, wherein the inner and outer sleeves have respective inner and outer cutting or “resecting” windows,  422  and  425 , with cooperating cutting edges in distal portions thereof, and wherein the distal portion of the outer sleeve that carries the cutting window  422  comprises a dielectric housing  440  and the distal working end  438  of the inner sleeve  415  that carries an inner cutting or resecting window  425  and comprises an RF electrode  450 . 
     In this variation, the dielectric material of the dielectric housing can comprises at least one of a ceramic, a glass and a polymer. For example, the ceramic material can be selected from the group consisting of alumina, zirconia, silicon nitride, yttria-stabilized zirconia, magnesia-stabilized zirconia, ceria-stabilized zirconia and zirconia toughened alumina. 
     The probe of  FIG. 10  further comprises a motor configured to selectively rotate in the inner sleeve in first and second rotational directions, with the radiofrequency (RF) source  480  coupled to the electrode. Further, a controller is operatively coupled to the motor and to the RF source. 
     In general, the controller includes an algorithm for stopping the motor to position the inner sleeve in a window-closed position or a window-open position. Further, the controller is configured to selectively operate in (i) a first mode in which the motor rotates or oscillates the inner sleeve with the RF electrode not energized for mechanically cutting tissue; (ii) a second mode in which the motor rotates or oscillates the inner sleeve with the RF electrode energized for electrosurgically cutting tissue; (iii) a third mode in which the inner sleeve is stationary in the window-closed position and the RF electrode is energized for applying coagulative or ablative energy to tissue; and (iv) a fourth mode in which the inner sleeve is stationary in the window-open position and the RF electrode is energized for applying coagulative or ablative energy to tissue. 
       FIG. 14  illustrates another variation of a working end  500  that includes an outer sleeve  505  and inner sleeve  510  that is adapted to rotate in bore  512  of the outer sleeve. In this variation, the outer sleeve  505  comprises a conductive metal tube without the ceramic housing or portion as in the previous variation of  FIGS. 10 and 11A . In this variation, the dielectric component that separates the conductive inner sleeve  510  from the conductive outer sleeve comprises a dielectric coating or layer  520  on the distal end  522  of the inner sleeve  510  and the polymer coating  528  over the proximal and medial portions of the inner sleeve  510 . The dielectric material  520  at the distal end  522  of the inner sleeve can be a ceramic or a glass material that can be configured with sharp edges  532  so as to provide a sharp, durable cutting edges  532  for cooperating with the edges  534  of the outer sleeve window  535 . In all other respects, the variation of  FIG. 14  can operate is the same manner as the variation described above in  FIGS. 10-13 . 
       FIG. 15  is a perspective view of a working end of a motor-driven, rotating inner sleeve similar to that of  FIGS. 11B-11C  with abrasive cutting features or sharp edges  536  for abrading bone. Thus, another mode of operation can be to rotate the inner sleeve at high speeds to use the abrasive features  536  to cut or abrade bone, typically without RF current being applied to the electrode surface. In some methods, and RF current can be applied to the electrode surface while abrading hard tissue or cauterizing purposes. 
       FIG. 16  illustrates another variation of working end  540  that operates under similar principles to that of the variation of  FIG. 10  wherein the outer sleeve  545  carries a distal dielectric or ceramic housing or portion  550  and a concentric inner sleeve  555  with cutting edges  556  is adapted to move relative to the outer sleeve window  560  in the dielectric housing  550 . However, in this variation, the inner sleeve  555  is adapted to reciprocate rather than rotate. In other respects, the cutting edges  556  of the inner sleeve  555  are configured with a close fit to the bore  564  in the dielectric housing  550  such that the inner sleeve cutting edges  556  and the edges  568  of outer sleeve window  560  shear tissue engaged by the window  560 . As described in previous embodiments, an RF source  480  is operatively coupled to both the inner and outer sleeves  545  and  555  to allow for electrosurgical cutting. In use, the reciprocation of inner sleeve thus can resect tissue mechanically or electrosurgically as described above. 
       FIG. 17  illustrates another variation of working end  580  that again is similar to that of  FIGS. 14 and 15 . In this variation, the outer sleeve  585  comprises a thin wall conductive metal with window  588  therein. The inner sleeve  590  comprises a metal sleeve encased in an insulative polymer  592  and a distal ceramic or glass portion  595  that functions as an electrical insulator as well as providing a cutting edge  596 . In this variation, the inner sleeve  590  again is adapted to reciprocate rather than rotate in the outer sleeve window  588 . Again, an RF source  480  is operatively coupled to both the inner and outer sleeves  585  and  590  to allow for electrosurgical cutting. In use, the reciprocation of inner sleeve and thus can resect tissue mechanically or electrosurgically as described above. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.