Patent Description:
Description of the Background Art. 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 including 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 surgical systems and methods for their use, such as improved arthroscopic tissue cutting and removal system wherein a motor-driven electrosurgical device is provided for cutting and removing 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.

<CIT>, <CIT> and <CIT> disclose similar arthroscopic cutters.

The invention is defined by the independent claim and other embodiments are listed in the dependent claims. No methods are claimed.

The present disclosure provides improved apparatus and methods for identifying and controlling working components, such as motor-driven and other powered components, of surgical systems, particularly for arthroscopic and other surgical systems including (<NUM>) handpieces having motor drive units and (<NUM>) probes which are selectively and removably attached to the handpieces. In exemplary embodiments, the present disclosure provides methods and systems which rely on magnets and magnetic sensors for providing information to system controllers both in a static mode, where a laparoscopic or other tool is not being driven, and in a dynamic mode, where the tool is being driven by the motor drive. In particular embodiments, the magnets are permanent magnets having North poles and South poles, where the magnets are typically mounted on or otherwise attached or coupled to components of a detachable probe forming part of an arthroscopic system, and the sensors are Hall sensors which are in the handpiece of the arthroscopic system. By using multiple magnets and multiple sensors, different types of information can be provided to the system controller, such as identification of the tool in the detachable probe, operating characteristics of the probe, system calibration information, and the like. While the exemplary embodiments of present disclosure typically rely on magnetic sensors, static and dynamic data acquisition from the tool probe to the associated controller and be accomplished with other sensors as well, such as optical sensors which are able to read information in both a static mode and in a dynamic mode.

In a first aspect of the present disclosure, an arthroscopic system comprises a handpiece and a probe. The handpiece includes a motor drive, and the probe has a proximal hub and an elongate shaft which extends about a longitudinal axis to a working end of the probe. The hub is configured for detachably coupling to the handpiece, and the motor drive is configured to couple to a rotating drive coupling in the hub when the hub is coupled to the handpiece. A first magnetic component is carried by the hub, and a second magnetic component is coupled to rotate with the rotating drive coupling.

In specific aspects, the hub may be configured for detachable coupling to the handpiece in opposing rotational orientations, such as an orientation where a working end of the probe is facing upwardly and a second orientation where the working end of the probe is facing downwardly relative to the handpiece. In such embodiments, the first magnetic component may comprise first and second independent magnets, typically permanent magnets have North poles and South poles, disposed in or on opposing sides of the hub and spaced outwardly from the longitudinal axis. The first and second independent magnets of the first magnetic component will typically have a "polar orientation," for example the North poles will be oriented in opposite directions relative to said axis. Typically, though not necessarily, the first and second independent magnets may have similar magnetic field strengths. In such embodiments, the handpiece may further comprise a first sensor configured for "statically" sensing a magnetic field of the first or second independent magnets when located adjacent the first sensor. By "statically" sensing, it is meant that the magnets do not need to be moving relative to the sensor. The sensor will thus be able to generate a signal indicating whether the working end is in its upward-facing orientation or its downward-facing orientation. The first sensor may be further configured for generating a probe identification signal based on the magnetic field strength (or other magnetic characteristic) which correlates a probe type with different magnetic field strengths, typically by using a look-up table maintained in an associated controller.

In still other embodiments, the second magnetic component comprises third and fourth independent magnets disposed in or on opposing sides of the rotating drive coupling. The third and fourth independent magnets of the second magnetic component will typically have North poles in opposing orientations relative to said axis, usually in a manner similar to the first and second independent magnets. The handpiece will further comprise a second sensor configured for sensing a magnetic field of the third or fourth independent magnets as the magnet comes into proximity to the second sensor. In this way, the second sensor can dynamically sense and generate a signal indicating a rotational parameter of the rotating drive coupling. For example, the rotational parameter may comprise a rotational position of the drive coupling. Alternatively or additionally, the rotational parameter may comprise a rotational speed of the drive coupling based on the rotational positioning over a time interval.

These arthroscopic and other surgical systems may be further configured for determining orientation of the motor-driven component so that the working end can be stopped in a desired position. For example, the second magnetic component carried by the drive coupling may be in a fixed predetermined rotational relationship to a motor-driven component in the working end. In this way, a rotational positioning of the component in the working end van be controlled based on the rotational position of the drive coupling.

Such systems of the present disclosure may further comprise a controller configured to receive the signals generated by the sensors and provide monitoring and control of the endoscopic or other surgical tool based on the received signals. For example, by receiving signals generated by the first sensor within the hub, at least one of probe-orientation and probe identification can be determined. Similarly, by receiving signals generated by the second sensor within the hub, the controller may be configured to monitor and/or control the motor speed and other operational characteristics.

In a second aspect of the present disclosure, an example method for performing an arthroscopic procedure comprises providing a system including a handpiece with a sensor. The system further comprises a probe having a proximal hub, a longitudinal axis, and a working end. The hub typically carries first and second magnets having North and South poles. The hub is selectively coupled to the handpiece with the working end of the probe in either an upward orientation or a downward orientation. The first magnet is located proximately to sensor when the working end is in the upward orientation, and the second magnet is located proximately to sensor when the working end is in the down orientation. In this way, an upward orientation or a downward orientation of the working end can be determined based on whether a North pole or a South pole of the magnet is proximate to the sensor. Such orientational information is used for a variety of purposes, including selecting a controller algorithm for operating the probe based on the identified orientation of the working end.

In a third aspect of the present disclosure, an arthroscopic or other surgical method comprises providing a system including a handpiece with a sensor. The system further comprises a probe with a proximal hub, a longitudinal axis, and a working end. The hub will carry first and second magnets of similar strengths and having North and South poles. The hub is coupled to the handpiece, and a magnetic strength of either (or both) of the magnets is sensed using a sensor in the handpiece to identify the probe type based on the sensed magnetic strength. Identification of the probe type is useful for a variety of purposes, including allowing selection of a control algorithm (to be used by a controller coupled to probe and sensors) to control the working end of the tool based on the identified probe type.

In a fourth aspect, an arthroscopic or other surgical procedure comprises providing a system including a handpiece with a motor drive. The system further comprises a probe having a proximal hub, a longitudinal axis, a rotating drive coupling, and a working end. The rotating drive coupling typically carries first and second magnets having North and South poles where each pole is positioned in a different orientation relative to the axis. The hub is attached to the handpiece to couple the motor drive to the rotating drive coupling in the hub. The rotating drive coupling actuates a motor-driven or other component in the working end, e.g. the motor drive may be activated to rotate the drive coupling and actuate the motor-driven component. A varying magnetic parameter is sensed with a sensor in the handpiece as the drive coupling rotates in order to generate sensor signals. A rotational position of the drive coupling can thus be determined, and the corresponding positions of the motor-driven component calculated using a positioning algorithm responsive to the sensor signals. The motor drive can be selectively deactivated at a desired rotational position based on the positional information which has been thus determined. After deactivating the motor drive, the system can dynamically brake the motor drive to thereby stop rotation of the drive coupling and stop movement of the motor-driven component in a selective stop position in a highly accurate manner.

In a fifth aspect of the present disclosure, an arthroscopic procedure comprises providing a system including a handpiece with a motor drive. The system further comprises a probe with a proximal hub and an elongate shaft extending about an axis to a working end. The hub is configured for detachable coupling to the handpiece, and the motor drive is configured to couple to a rotating drive coupling in the hub. The drive coupling, in turn, carries first and second magnets with North and South poles positioned in different orientations relative to the axis. The hub is coupled to the handpiece, and the motor drive is activated to rotate the drive coupling and magnets through an arc of at least <NUM>°. A varying strength of each magnet is then sensed with a sensor in the handpiece as the drive coupling rotates. A rotational position of the drive coupling responsive to the varying strength of each magnet can be calibrated in order to increase accuracy in subsequent calculation of the sensed strengths of the magnets.

In a sixth aspect of the present disclosure, an arthroscopic procedure comprises providing a handpiece with a motor drive. The system further comprises a probe having a proximal hub and an elongate shaft extending about a longitudinal axis to a working end having a motor-driven component. The motor-driven component includes a radio frequency (RF) electrode, and a hub is configured for detachable coupling to the handpiece. The motor drive is configured to couple to a rotating drive in the coupling of the hub, and the rotating drive coupling is configured to carry first and second magnets with North and South poles positioned in different orientations relative to the axis. The hub is coupled to the handpiece, and the drive coupling and motor-driven component are positioned in a selected stop position. The RF electrode is typically exposed in the selected stop position and can be introduced to a target site to engage or interface with tissue. RF current is then delivered to the RF electrode, and a positioning algorithm responsive to sensor signals continuously monitors the rotational position of the drive coupling and the corresponding position of the motor-driven component and the RF electrode while RF current is being delivered. Such position monitoring is useful because it allows the positioning algorithm to sense a rotation or rotational deviation greater than a predetermined amount, in which case the delivery of RF current to the RF electrode can be terminated. Additionally or alternatively, the positioning algorithm can further activate or adjust the motor drive to return the RF electrode back to a selected or desired stop position.

In a seventh aspect, an arthroscopic procedure comprises providing a handpiece with a motor drive and a probe with a proximal hub. An elongate shaft of the hub extends about an axis to a working end, and a motor driven component in the working end includes an RF electrode. The hub is configured for detachably coupling to the handpiece, and the motor drive is configured to couple to a rotating drive coupling in the hub. The rotating drive carries first and second magnets with North and South poles having different orientations relative to the axis. The hub is coupled to the handpiece, and the drive coupling and motor-driven component may be positioned in a selected stop position. The RF electrode may be engaged against a target issue surface or interface, and an RF current may be delivered to the RF electrode. Using a positioning algorithm responsive to sensor signals indicating a rotational position of the drive coupling, the RF electrode can be oscillated in the range from <NUM> to <NUM>. Often, oscillation of the RF electrode at a rate ranging from <NUM> to <NUM>.

In an eighth aspect, the present disclosure comprises a method for providing information from a surgical probe to a controller. A hub of the probe is attached to a handpiece connected to the controller. The hub carries indicia, and a first set of data obtained from reading the first set of indicia on the hub may be read using a first sensor on the handpiece, where the first set of data can then be sent to the controller. A second set of indicia on the hub is also read using a second sensor on the handpiece, and a second set of data obtained from the second reading may also be sent to the controller. The first set of data includes at least one of probe identification information and probe orientation information, and the second set of data includes at least probe operational information.

In specific embodiments, the first and/or second set of indicia may comprise magnets, as taught in any of previously described embodiments. In alternative embodiments, however, the first and/or second sets of indicia may comprise optical encoding or any other type of data encoding that can be read using sensors in the handpiece. For example, the first set of indicia may comprise optical encoding including a scannable code on a stationary component of the hub, such as a housing. The first set of indicia incorporates said at least one of probe identification information and probe orientation information and can be read when the code is static relative to the handpiece, typically using a stationary optical scanner, such as a bar or 3D code reader. In other examples, the second set of indicia may comprise optical encoding configured to be read by a scannable code reader, e.g., markings on a rotatable component of the hub, wherein at least the probe operational information is configured to read from the markings as the rotatable component dynamically rotates. For example, the markings may be read by an optical counter that can determine a rotation speed, such as revolutions per minute (RPM).

Various embodiments of the present invention will now be discussed with reference to the appended drawings <NUM>-<NUM>. It should be appreciated that the drawings depict only typical embodiments of the invention and are therefore not to be considered limiting in scope.

The present invention relates to bone cutting and tissue removal devices. Several variations of the disclosure 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>, the arthroscopic system <NUM> of the present disclosure provides a handpiece <NUM> with motor drive <NUM> and a disposable shaver assembly or probe <NUM> with a proximal hub <NUM> that can be received by receiver or bore <NUM> in the handpiece <NUM>. In one aspect, the probe <NUM> has a working end <NUM> 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 <FIG>, <FIG> and <FIG>, it can be seen that probe <NUM> has a shaft <NUM> extending along longitudinal axis <NUM> that comprises an outer sleeve <NUM> and an inner sleeve <NUM> rotatably disposed therein with the inner sleeve <NUM> carrying a distal ceramic cutting member <NUM> (<FIG>). The shaft <NUM> extends from the proximal hub <NUM> wherein the outer sleeve <NUM> is coupled in a fixed manner to the hub <NUM> which can be an injection molded plastic, for example, with the outer sleeve <NUM> insert molded therein. The inner sleeve <NUM> is coupled drive coupling <NUM> that is configured for coupling to the rotating motor shaft <NUM> of motor drive unit <NUM>. More in particular, the rotatable cutting member <NUM> that is fabricated of a ceramic material with sharp cutting edges on opposing sides 152a and 152b of window <NUM> therein for cutting soft tissue. The motor drive <NUM> is operatively coupled to the ceramic cutter to rotate the cutting member at speeds ranging from <NUM>,<NUM> rpm to <NUM>,<NUM> rpm. In <FIG>, it can be seen that cutting member <NUM> also carries an RF electrode <NUM> in a surface opposing the window <NUM>. The cutting member <NUM> rotates and shears tissue in the toothed opening or window <NUM> in the outer sleeve <NUM> (<FIG>). A probe of the type shown in <FIG> is described in more detail in co-pending and commonly owned patent application <CIT> (Atty. Docket <NUM>-<NUM>) titled ARTHROSCOPIC DEVICES AND METHODS.

As can be seen in <FIG>, the probe <NUM> is shown in two orientations for detachable coupling to the handpiece <NUM>. More particularly, the hub <NUM> can be coupled to the handpiece <NUM> in an upward orientation indicated at UP and a downward orientation indicated at DN where the orientations are <NUM>° opposed from one another. It can be understood that the upward and downward orientations are necessary to orient the working end <NUM> either upward or downward relative to the handpiece <NUM> to allow the physician to interface the cutting member <NUM> with targeted tissue in all directions without having to manipulate the handpiece in <NUM>° to access tissue.

In <FIG>, it can be seen that the handle <NUM> is operatively coupled by electrical cable <NUM> to a controller <NUM> which controls the motor drive unit <NUM> Actuator buttons 166a, 166b or 166c on the handle <NUM> can be used to select operating modes, such as various rotational modes for the ceramic cutting member <NUM>. In one variation, a joystick <NUM> can be moved forward and backward to adjust the rotational speed of the ceramic cutting member <NUM>. The rotational speed of the cutter can continuously adjustable, or can be adjusted in increments up to <NUM>,<NUM> rpm. An LCD screen <NUM> is provided in the handpiece for displaying operating parameters, such as cutting member RPM, mode of operation, etc..

It can be understood from <FIG> that the system <NUM> and handpiece <NUM> is adapted for use with various disposable probes which can be designed for various different functions and procedures For example, <FIG> illustrates a different variation of a probe working end 200A that is similar to working end <NUM> of probe <NUM> of <FIG>, except the ceramic cutting member <NUM> extends distally from the outer sleeve <NUM> and the cutting member has burr edges <NUM> for cutting bone. The probe of <FIG> is described in more detail in co-pending and commonly owned patent application <CIT> (Atty. Docket <NUM>-<NUM>) titled ARTHROSCOPIC DEVICES AND METHODS. <FIG> illustrates a different variation of a probe working end 200B with a reciprocating electrode <NUM> in a type of probe described in more detail in co-pending and commonly owned patent application <CIT> (Atty. Docket <NUM>-<NUM>) titled ARTHROSCOPIC DEVICES AND METHODS. In another example, <FIG> illustrates another variation of a probe working end 200C that has an extendable-retractable hook electrode <NUM> in a probe type described in more detail in co-pending and commonly owned patent application <CIT> (Atty. Docket <NUM>-<NUM>) titled ARTHROSCOPIC DEVICES AND METHODS. In yet another example, <FIG> illustrates a variation of a working end 200D in a probe type having an openable-closable jaw structure <NUM> actuated by reciprocating member <NUM> for trimming meniscal tissue or other tissue as described in more detail in co-pending and commonly owned patent application <CIT> (Atty. Docket <NUM>-<NUM>) titled ARTHROSCOPIC DEVICES AND METHODS. All of the probes of <FIG> can have a hub similar to hub <NUM> of probe <NUM> of <FIG> for coupling to the same handpiece <NUM> of <FIG>, with some of the probes (see <FIG>) having a hub mechanism for converting rotational motion to linear motion.

<FIG> further shows that the system <NUM> also includes a negative pressure source <NUM> coupled to aspiration tubing <NUM> which communicates with a flow channel <NUM> in handpiece <NUM> and can cooperate with any of the probes <NUM>, 200A, 200B or 200C of <FIG>, <FIG>, <FIG> and <FIG>. In <FIG> it also can be seen that the system <NUM> includes an RF source <NUM> which can be connected to an electrode arrangement in any of the probes <NUM>, 200A, 200B or 200C of <FIG>, <FIG>, <FIG> and <FIG>. The controller <NUM> and microprocessor therein together with control algorithms are provided to operate and control all functionality, which includes controlling the motor drive <NUM> to move a motor-driven component of any probe working end <NUM>, 200A, 200B or 200C, as well as for controlling the RF source <NUM> and the negative pressure source <NUM> which can aspirate fluid and tissue debris to collection reservoir <NUM>.

As can be understood from the above description of the system <NUM> and handpiece <NUM>, the controller <NUM> 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 <NUM>, 200A, 200B, 200C or 200D of <FIG> and <FIG> are coupled to handpiece <NUM>, the controller <NUM> will recognize the probe type and then select algorithms for operating the motor drive <NUM>, RF source <NUM> and negative pressure source <NUM> 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 <NUM> 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 <NUM>, 200A, 200B, 200C and 200D (<FIG>, <FIG>) 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 <NUM> with an electrode <NUM> needs to have the electrode centered within an outer sleeve window <NUM> in a default position such as depicted in <FIG>. Some of these systems, algorithms and methods of use are described next.

Referring to <FIG> and <FIG>, it can be seen that handpiece <NUM> carries a first Hall effect sensor <NUM> in a distal region of the handpiece <NUM> adjacent the receiving passageway <NUM> that receives the hub <NUM> of probe <NUM>. <FIG> corresponds to the probe <NUM> and working end <NUM> in <FIG> being in the upward orientation indicated at UP. <FIG> corresponds to probe <NUM> and working end <NUM> in <FIG> being in the downward orientation indicated at DN. The handpiece <NUM> carries a second Hall effect sensor <NUM> adjacent the rotatable drive coupling <NUM> of the probe <NUM>. The probe <NUM> carries a plurality of magnets as will be described below that interact with the Hall effect sensors <NUM>, <NUM> 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 <NUM> relative to the handpiece <NUM>, and (iii) the rotational position and speed of rotating drive collar <NUM> from which a position of either rotating or reciprocating motor-driven components can be determined.

The sectional views of <FIG> show that hub <NUM> of probe <NUM> carries first and second magnets 250a and 250b in a surface portion thereof. The Hall sensor <NUM> in handpiece <NUM> is in axial alignment with either magnet 250a or 250b when the probe hub <NUM> is coupled to handpiece <NUM> in an upward orientation (<FIG> and <FIG>) or a downward orientation (<FIG> and <FIG>). In one aspect as outlined above, the combination of the magnets 250a and 250b and the Hall sensor <NUM> can be used to identify the probe type. For example, a product portfolio may have from <NUM> to <NUM> or more types of probes, such as depicted in <FIG> and <FIG>, and each such probe type can carry magnets 250a, 250b having a specific, different magnetic field strength. Then, the Hall sensor <NUM> 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 <NUM> to select the controller algorithms for operating the identified probe, which can include parameters for operating the motor drive <NUM>, negative pressure source <NUM> and/or RF source <NUM> as may be required for the probe type. As can be seen in <FIG>, <FIG>, the probe hub <NUM> can be coupled to handpiece <NUM> in upward and downward orientations, in which the North (N) and South (S) poles of the magnets 250a, 250b are reversed relative to the probe axis <NUM>. Therefore, the Hall sensor <NUM> and associated algorithms look for magnetic field strength regardless of polarity to identify the probe type.

Referring now to <FIG>, <FIG> and <FIG>, the first and second magnets 250a and 250b with their different orientations of North (N) and South (S) poles relative to central longitudinal axis <NUM> of hub <NUM> are also used to identify the upward orientation UP or the downward orientation DN of hub <NUM> and working end <NUM>. In use, as described above, the physician may couple the probe <NUM> to the handpiece receiving passageway <NUM> with the working end <NUM> 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 <NUM> in the window <NUM> of the outer sleeve <NUM> of working end <NUM> need to "learn" whether the working end is facing upward or downward, because the orientation or the rotating cutting member <NUM> relative to the handpiece and Hall sensor <NUM> would vary by <NUM>°. The Hall sensor <NUM> 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 250a or 250b is facing upwardly and is proximate the Hall sensor <NUM>.

In another aspect of the disclosure, in probe <NUM> (<FIG>) and other probes, the motor-driven component of a working end, such as rotating cutter <NUM> of working end <NUM> of <FIG> and <FIG> needs to stopped in a selected rotational position relative to a cut-out opening or window <NUM> in the outer sleeve <NUM>. 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 <FIG> and the jaw structure of <FIG>. In all probes, the motor drive <NUM> couples to the rotating drive coupling <NUM>, thus sensing the rotational position of the drive coupling <NUM> can be used to determine the orientation of the motor-driven component in the working end. More in particular, referring to <FIG> and <FIG>, the drive coupling <NUM> carries third and fourth magnets 255a or 255b with the North (N) and South (S) poles of magnets 255a or 255b being reversed relative to the probe axis <NUM>. Thus, Hall sensor <NUM> can sense when each magnet rotates passes the Hall sensor and thereby determine the exact rotational position of the drive coupling <NUM> twice on each rotation thereof (once for each magnet 255a, 255b). Thereafter, a controller tachometer algorithm using a clock can determine and optionally display the RPM of the drive coupling <NUM> and, for example, the cutting member <NUM> of <FIG>.

In another aspect of the disclosure, the Hall sensor <NUM> and magnets 255a and 255b (<FIG> and <FIG>) 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 <NUM> of <FIG> and <FIG> in a preselected rotational position. In <FIG>, it can be seen that the inner sleeve <NUM> and a "first side" of cutting member <NUM> and window <NUM> therein is stopped and positioned in the center of window <NUM> of outer sleeve <NUM>. The stationary position of cutting member <NUM> and window <NUM> in <FIG> may be used for irrigation or flushing of a working space to allow for maximum fluid outflow through the probe.

<FIG> depicts inner sleeve <NUM> and a "second side" of cutting member <NUM> positioned about the centerline of window <NUM> in the outer sleeve <NUM>. The stationary or stopped position of cutting member <NUM> in <FIG> is needed for using the RF electrode <NUM> to ablate or coagulate tissue. It is important that the electrode <NUM> is maintained along the centerline of the outer sleeve window <NUM> since the outer sleeve <NUM> typically comprises return electrode <NUM>. The position of electrode <NUM> in <FIG> is termed herein a "centerline default position". If the cutting member <NUM> and electrode <NUM> were rotated so as to be close to an edge 262a or 262b of window <NUM> in outer sleeve <NUM>, RF current could arc between the electrodes <NUM> and <NUM> 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 <FIG> and <FIG>, the controller <NUM> can always determine in real time the rotational position of drive coupling <NUM> and therefore the angular or rotational position of the ceramic cutting member <NUM> and electrode <NUM> can be determined. A controller algorithm can further calculate the rotational angle of the electrode <NUM> away from the centerline default position as drive coupling <NUM> rotates the electrode <NUM> 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 255a or 255b drops a specified amount from a known peak value in the centerline default position, it means the electrode <NUM> has moved away from the center of the window <NUM>. In one variation, if the electrode <NUM> 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 <NUM> on handpiece <NUM> 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 <NUM> and the outer sleeve electrode <NUM>.

It can be understood that during use, when the electrode <NUM> is in the position shown in <FIG>, the physician may be moving the energized electrode over tissue to ablate or coagulate tissue. During such use, the cutting member <NUM> and electrode <NUM> can engage or catch on tissue which inadvertently rotate the electrode <NUM> 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 <NUM> during RF energy delivery in both an ablation mode and a coagulation mode to determine if the electrode <NUM> and inner sleeve <NUM> have been bumped off the centerline position. In a variation, the controller algorithms can be configured to then re-activate the motor drive <NUM> to move the inner sleeve <NUM> and electrode <NUM> back to the default centerline position sleeve if electrode <NUM> 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 <NUM> when it is moved back to the to the default centerline position. Alternatively, the controller <NUM> can require the physician to manually re-start the delivery of RF current to the RF electrode <NUM> when it is moved back to the to the centerline position. In an aspect of the disclosure, the drive coupling <NUM> and thus magnets 255a and 255b are attached to inner sleeve <NUM> and cutting member <NUM> in a pre-determined angular relationship relative to longitudinal axis <NUM> so that the Hall sensor generates signals responsive to magnets 255a, 255b 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 <NUM>, <FIG> schematically illustrates the algorithm and steps of the stop mechanism. In one variation, referring to <FIG>, the stop mechanism corresponding to the disclosure uses (i) a dynamic braking method and algorithm to stop the rotation of the inner sleeve <NUM> and cutting member <NUM> (<FIG>, <FIG>) 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 <NUM> to slightly reverse (or move forward) the rotation of drive coupling <NUM> and inner sleeve <NUM> as needed to position the cutting member <NUM> and electrode <NUM> within at the centerline position or within <NUM>° to <NUM>° of the targeted centerline default position. Dynamic braking is described further below. <FIG> schematically illustrates various aspects of controller algorithms for controlling the rotational speed of the cutting member and for stopping the cutting member <NUM> in the default centerline position.

In <FIG>, it can be understood that the controller <NUM> is operating the probe <NUM> of <FIG> and <FIG> 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 <NUM> rotates the cutting member <NUM> in one direction and then reverses rotation as is known in the art. At higher rotational speeds such as <NUM>,<NUM> RPM to <NUM>,<NUM> RPM, it is not practical or feasible to acquire a signal from Hall sensor <NUM> that indicates the position of a magnet 255a or 255b in the drive coupling <NUM> to apply a stop algorithm. In <FIG>, when the physician stop cutting with probe <NUM> by releasing actuation of an actuator button or foot pedal, current to the motor drive <NUM> is turned off. Thereafter, the controller algorithm uses the Hall sensor <NUM> to monitor deceleration of rotation of the drive coupling <NUM> and inner sleeve <NUM> until a slower RPM is reached. The deceleration period may be from <NUM> to <NUM> sec and typically is about <NUM>. When a suitable slower RPM is reached which is called a "search speed" herein (see <FIG>), the controller <NUM> re-activates the motor drive <NUM> to rotate the drive coupling at a low speed ranging from <NUM> RPM to <NUM>,<NUM> RPM and in one variation is between <NUM> RPM and <NUM> RPM. An initial "search delay" period ranging from <NUM> to <NUM> 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 <NUM> and electrode <NUM> correspond to the centerline default position of <FIG>, the control algorithm then applies dynamic braking to instantly stop rotation of the motor drive shaft <NUM>, drive coupling <NUM> and the motor-driven component of the probe. <FIG> further illustrates that the controller can check the magnet/drive coupling <NUM> 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 <NUM> 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> may typically stop the rotation of the drive coupling <NUM> with a variance of up to about <NUM>°- <NUM>° 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 <NUM>, 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. com/support/abdrives/documentation/techpapers/RegenOverview01. 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 disclosure, 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 <NUM> to continuously monitor the field strength of magnets 255a and 255b as the drive coupling <NUM> 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 <NUM>. 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 255a and 255b which may vary from the specified strength. After a new single-use probe <NUM> (<FIG>) is coupled to the handpiece <NUM>, and after actuation of the motor drive <NUM>, the positioning algorithm will rotate the drive coupling at least <NUM>° and more often at least <NUM>° while the Hall sensor <NUM> quantifies the field strength of the particular probe's magnets 255a and 255b. 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 <NUM>°, 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 <NUM>.

Another aspect of the disclosure relates to an enhanced method of use using a probe working end with an electrode, such as the working end <NUM> of <FIG> and <FIG>. As described above, a positioning algorithm is used to stop rotation of the electrode <NUM> in the default centerline position of <FIG>. An additional "slight oscillation" algorithm is used to activate the motor drive <NUM> contemporaneous with RF current to the electrode <NUM>, 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 <NUM> 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'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 <NUM>° to <NUM>° in each direction away from the centerline default position. More often, the predetermined degree of angular motion is from <NUM>° to <NUM>° 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 <NUM> RPM to <NUM>,<NUM> RPM, and more often from <NUM> RPM to <NUM>,<NUM> RPM. Stated another way, the frequency of oscillation can be from <NUM> to <NUM>,<NUM> and typically between <NUM> and <NUM>.

While the above description of the slight oscillation algorithm is provided with reference to electrode <NUM> on a rotating cutting member <NUM> of <FIG>, it should be appreciated that a reciprocating electrode <NUM> as shown in the working end 200C of <FIG> end could also be actuated with slight oscillation. In other words, the hook shape electrode <NUM> of <FIG> could be provided with a frequency of oscillation ranging from <NUM> to <NUM>,<NUM> and typically between <NUM> and <NUM>.

<FIG> are longitudinal sectional views of a probe hub <NUM>' that corresponds to the working end 200B of <FIG> which has a reciprocating electrode <NUM>. In <FIG>, the handpiece <NUM> and Hall affect sensors <NUM> and <NUM> are of course the same as described above as there is no change in the handpiece <NUM> for different types of probes. The probe hub <NUM>' of <FIG> is very similar to the hub <NUM> of <FIG> with the first and second identification/orientation magnets 250a and 250b being the same. The third and fourth rotation al position magnets 255a and 255b also are the same and are carried by drive coupling <NUM>'. The probe hub <NUM>' of <FIG> only differs in that the drive coupling <NUM> rotates with a cam mechanism operatively coupled to inner sleeve <NUM>' to convert rotational motion to linear motion to reciprocate the electrode <NUM> in working end 200B of <FIG>. A similar hub for converting rotational motion to linear motion is provided for the working ends 200C and 200D of <FIG>, respectively, which each have a reciprocating component (<NUM>, <NUM>) in its working end.

Now turning to <FIG>, <FIG> and <FIG>, another variation of an arthroscopic shaver or resection probe <NUM> is shown which somewhat similar to that of <FIG> and <FIG> which comprises a tubular cutter having a proximal hub <NUM> coupled to an elongated shaft assembly <NUM> that extends about central longitudinal axis <NUM>. The shaft assembly comprises an outer sleeve assembly <NUM> and a co-axial or concentric inner sleeve assembly <NUM> that extends to a shaft working end <NUM>. The hub <NUM> again is adapted for coupling to a handpiece and motor drive controlled by a controller 420A. The controller 420A further controls the RF source 420B and negative pressure source 420C as described previously. The controller 420A includes algorithms having the features described in previous embodiments for rotating the inner sleeve assembly <NUM> as well as stopping the inner sleeve <NUM> in a selected rotational position, such as a window-closed or window-open position. The working end <NUM> again has an outer sleeve resecting window <NUM> in the outer sleeve assembly <NUM> that cooperates with an inner sleeve resecting window <NUM> (<FIG>) in the inner sleeve assembly <NUM> for engaging and resecting tissue.

The variation or probe <NUM> in <FIG>, <FIG> and <FIG> differs from previous embodiments in that the inner sleeve assembly <NUM> has a distal end portion <NUM> that comprises a combination of a longitudinal dielectric member or body <NUM> coupled to a longitudinal conductive member or portion <NUM>. The dielectric member <NUM> can be a ceramic or glass material and the longitudinal conductive portion <NUM> typically is stainless steel. When assembled, the dielectric member <NUM> and longitudinal conductive portion <NUM> have outer surface that contact one another along an interface <NUM> which is important for reasons described in more detail below.

As can be seen in <FIG>, which shows components of the inner sleeve assembly <NUM> separated, the longitudinal dielectric member <NUM> carries an active electrode <NUM> which may be also may be referred to as a first polarity electrode herein. For convenience, the side of the inner sleeve assembly <NUM> that carries the electrode <NUM> is called the electrode side ES and the opposing side which carries inner window <NUM> is called the window side WS. Referring to <FIG>, the inner sleeve resecting window <NUM> has circumferentially spaced-apart first and second cutting edges 448a and 448b that are sharp for mechanically resecting tissue as such cutting edges 448a, 448b shear tissue when rotating or rotationally oscillating across the cutting edges 450a and 450b of the outer sleeve window <NUM>. Of particular interest, the longitudinal conductive metal portion <NUM> comprises a return electrode <NUM> (which also may be termed a second polarity electrode herein) which cooperates with the first polarity or active electrode <NUM> to deliver energy to tissue. The active and return electrodes <NUM> and <NUM> are operatively coupled to RF source 420B and controller 420A as described previously. The outer sleeve assembly <NUM> has a conductive metal outer tubular member <NUM> with bore <NUM> therein that extends proximally to the hub <NUM> and distally to the distal end portion or housing <NUM> that carries the outer sleeve window <NUM>. The inner sleeve assembly <NUM> has a co-axial conductive metal inner tubular member <NUM> that extends proximally to the hub <NUM> and extends distally to couple to the assembly of the longitudinal dielectric member <NUM> and the longitudinal metal portion <NUM>. The co-axial metal inner tubular member <NUM> rotates in the bore <NUM> of the outer tubular member <NUM>.

As can be seen best in <FIG> and <FIG>, the longitudinal metal portion <NUM> has dual functions in that the carries the inner cutting window <NUM> with circumferentially spaced-apart first and second cutting edges 448a and 448b and also functions as a return electrode <NUM> when in a window-closed position of <FIG>, as will be described further below.

Now referring to <FIG>, the inner sleeve assembly <NUM> again is shown separated from the outer sleeve assembly <NUM> and is rotated <NUM>° so that the electrode side ES faces downward and the window side WS is in an upward position. Thus, it can be seen that the longitudinal metal portion <NUM> carries the inner resecting window <NUM>. Further, the longitudinal metal portion <NUM> extends distally around the tip portion <NUM> of the inner sleeve assembly <NUM> to thus provide substantial hoop strength as the tip portion <NUM> distally surrounds the longitudinal dielectric member <NUM> on opposing sides of the distal end <NUM> of the dielectric member <NUM>. As can be seen in <FIG>, the proximal end <NUM> of the assembly of the longitudinal dielectric member <NUM> and the longitudinal metal portion <NUM> is dimensioned for insertion into the bore <NUM> of the thin wall tubular sleeve <NUM> to complete the structural components of the inner sleeve assembly <NUM>. Thus, it can be seen how the tubular sleeve <NUM> with bore <NUM> therein slides over and engages with the longitudinal dielectric member <NUM> and longitudinal metal portion <NUM> to provide a strong connection around the proximal end <NUM> of the components. As can best be seen in <FIG>, the lateral sides 470a and 470b of the longitudinal dielectric member <NUM> are configured to slide into receiving recesses or grooves 472a and 472b on either side of the open channel <NUM> in the longitudinal metal portion <NUM> to thereby lock the two components <NUM> and <NUM> together.

<FIG> shows the exploded view of the components of <FIG> rotated <NUM>° degrees to again show the lateral sides 470a, 470b of the dielectric member <NUM> configured for insertion into the receiving grooves 472a, 472b on either side of the channel <NUM> in the longitudinal metal portion <NUM>.

Now turning to <FIG> and <FIG>, the electrical connections to the active electrode <NUM> and return electrodes <NUM> can be described. In the exploded view of <FIG>, it can be seen that an elongated electrical lead <NUM> is adapted to extend longitudinally over the inner tubular member <NUM> (<FIG>) to a pad portion <NUM> that is bendable and adapted to be inserted into a pad recess <NUM> in the longitudinal dielectric member <NUM>. The electrical lead <NUM> is covered with an insulator (not shown) except for the pad portion <NUM>. As can be easily understood, the active electrode <NUM> comprises a metal such as stainless steel, tungsten or any other suitable conductive metal with first and second legs 478a and 478b that are adapted for insertion through receiving channels 482a and 482b in the dielectric member <NUM> which extend into the pad recess <NUM>. Thus, it can understood that the electrode <NUM> is cantilevered over a grooved portion <NUM> of the dielectric member <NUM> distally from the dual receiving channels 482a and 482b in the dielectric member <NUM>. The pad <NUM> of the electrical lead <NUM> then is placed in the contact with the legs 478a and 478b of the electrode <NUM> and soldered or otherwise electrically coupled in the recess <NUM>. Finally, a potting material (not shown) is used to cover and fill in over the electrical pad <NUM> and the recess <NUM>. Further, referring to <FIG>, it can be seen that tubular member <NUM> has a flattened surface <NUM> for accommodating the electrical lead <NUM> as the tubular member <NUM> and bore <NUM> therein slide over the proximal end <NUM> of the dielectric member <NUM> and metal portion <NUM>. The flattened surface <NUM> of the tubular member <NUM> as seen in <FIG> allows an insulator layer <NUM> (such as a heat shrink material) shown in phantom view to cover the entirety of the tubular member <NUM>, the insulated electrical lead <NUM>, and the proximal and medial portions <NUM>, <NUM> of the dielectric member <NUM> and the longitudinal metal portion <NUM>. This describes the electrical lead <NUM> extending to the active electrode <NUM> carried within the dielectric member <NUM>. The proximal end (not shown) of the electrical lead <NUM> extends into the hub <NUM> (<FIG>) and thereafter connects to electrical contacts in a handle which allows for rotation of the inner sleeve assembly <NUM> and for coupling electrical energy to the electrical lead <NUM>, as described in earlier embodiments.

As described above, the longitudinal metal portion <NUM> of the inner sleeve assembly <NUM> (<FIG>, <FIG>) comprises a return electrode <NUM>. However, the inner sleeve assembly <NUM> does not carry electrical lead to the longitudinal metal portion <NUM>. Rather, the outer sleeve assembly <NUM> of <FIG>, <FIG> and <FIG> includes an elongate metal outer tubular member <NUM> that comprises an electrical conductor and is adapted to carry current from the hub <NUM> to the distal end or housing portion <NUM> of the outer sleeve assembly <NUM>. Since the longitudinal metal portion <NUM> of the inner sleeve assembly <NUM> rotates with a close fit within the bore <NUM> of the outer tubular member <NUM>, the longitudinal metal portion <NUM> becomes a return electrode <NUM> due to its contact with the outer tubular member <NUM>. Thus, referring to <FIG>, the longitudinal metal conductive portion <NUM> and the distal end housing <NUM> of the outer tubular member <NUM> both comprise a return electrode <NUM>.

In another aspect of the disclosure, referring to <FIG> and <FIG>, the active electrode <NUM> is dome-shaped with a surface <NUM> that has a radius or curvature that is a segment of a cylindrical shape so that the outer surface <NUM> of the dome of the electrode <NUM> when viewed in a transverse sectional view (<FIG>) is substantially aligned with the outer cylindrical surfaces <NUM> of the dielectric member <NUM> and longitudinal metal portion <NUM>. The dome-shaped surface <NUM> of the electrode <NUM> is advantageous for engaging tissue since it projects outward as opposed to a flat-surface electrode. Further, the thicker, dome-shaped central portion of electrode <NUM> results in far slower degradation and disintegration of the electrode <NUM> during prolonged use. Such electrode durability is important for arthroscopic procedures in which the electrosurgical components of the disclosure may be used for many minutes.

Referring again to <FIG>, in one aspect of the disclosure, the longitudinal dielectric member <NUM> together with the longitudinal metal portion <NUM> form a wall around an interior channel <NUM> therein that communicates within bore <NUM> in the inner tubular member <NUM> and a negative pressure source 420C for aspirating tissue chips and fluid from a working space as is known in the art. In one variation shown in <FIG>, the metal wall portion <NUM> (disregarding the opening of window <NUM> therein) extends radially around axis <NUM> and the interior channel <NUM> in a radial angle RA1 of at least <NUM>°. Often, the metal wall portion <NUM> will extend radially around the interior channel in a radial angle RA1 of at least <NUM>° or at least <NUM>°. When describing the metal wall portion <NUM> herein that extends in a radial angle indicated at RA1 in <FIG>, it is meant to refer, for example, to the metal wall portion <NUM> of <FIG> which is a transverse section 16B-16B in <FIG> which is proximal to window <NUM>, where such a wall portion <NUM> provides the required hoop strength to the metal portion <NUM>. In this variation, referring to <FIG>, the wall <NUM> of the dielectric member <NUM> extends radially around the interior channel <NUM> in a radial angle RA2 of at least <NUM>° or at least <NUM>°. Further, still referring to <FIG>, the dome-shaped electrode <NUM> has a surface <NUM> that extends radially around the axis <NUM> in a radial angle RA3 of at least <NUM>° or at least <NUM>°.

Now turning to <FIG>, another important aspect of the disclosure can be described. As can be seen in <FIG>, the inner sleeve assembly <NUM> has been stopped in a selected rotational position wherein the electrode <NUM> carried by the dielectric member <NUM> is positioned centrally in the resecting window <NUM> of the outer sleeve assembly <NUM>. In this variation, it should be appreciated that the outer sleeve window <NUM> is shown with sharp metal cutting edges without teeth or serrations, but it should be appreciated that the outer sleeve window <NUM> can have any form of sharp teeth, serrations or the like and fall within the scope of the disclosure.

In <FIG>, it can also be seen that the longitudinal metal portion <NUM> of the inner sleeve assembly <NUM> is exposed in the outer sleeve window <NUM> when the outer sleeve assembly <NUM> has been stopped in the rotational position where electrode <NUM> is positioned centrally in the resecting window <NUM>. As described above, both the distal portion or housing <NUM> of the outer sleeve assembly <NUM> and the longitudinal metal portion <NUM> of the inner sleeve assembly <NUM> comprises return electrodes <NUM>. <FIG> shows RF current paths CP that indicate the shortest path for RF current between the active electrode <NUM> and the return electrode <NUM> when operating in conductive saline environment. As can be seen in <FIG>, the shortest RF current paths CP are from the active electrode <NUM> to the longitudinal metal portion <NUM> along interface <NUM> of the dielectric member <NUM> and metal portion <NUM> and not the cutting edges 450a and 450b of the outer window <NUM> in distal housing <NUM> which comprise the return electrode <NUM>. This aspect of the disclosure
is very important in that the location of the interface <NUM> between the dielectric member <NUM> and metal portion <NUM> is critical to prevent a short current path CP to the cutting edges 450a and 450b of outer window <NUM>. If substantial RF current path were directly from electrode <NUM> to cutting edges 450a and 450b, the RF plasma at the cutting edges would rapidly degrade and dull such edges. In turn, the dull cutting edges of the outer sleeve window <NUM> would diminish the resection rate resulting from rotating or oscillating the inner sleeve assembly <NUM> and window <NUM> in the outer sleeve window <NUM>.

In general, a surgical a probe for resecting tissue corresponding to the disclosure (<FIG>) comprises an elongated shaft extending about a longitudinal axis <NUM> comprising co-axial outer and inner sleeve assemblies <NUM>, <NUM> having respective outer and inner resecting windows <NUM> and <NUM> in distal ends thereof, wherein the inner sleeve assembly has (i) a longitudinal dielectric wall portion that carries a first polarity or active electrode <NUM>, and (ii) a conductive metal wall portion with an inner resecting window <NUM> with circumferentially spaced-apart first and second conductive cutting edges 448a and 448b that comprise a return electrode <NUM>, wherein the active electrode <NUM> is spaced apart from the cutting edges 448a, 448b by at least <NUM>. An RF source 420B coupled to the active and return electrodes. In other variations, the first and second polarity electrodes <NUM>, <NUM> (or active and return electrodes <NUM>, <NUM>) are spaced apart by at least <NUM> or at least <NUM>. In a variation, the dielectric member <NUM> defines a longitudinal interface <NUM> with a longitudinal edge of an conductive longitudinal metal portion <NUM> which comprising a second polarity or return electrode.

In general, referring to <FIG>, a tissue resecting probe corresponding to the disclosure comprises an elongated shaft <NUM> extending about a longitudinal axis <NUM> and further comprises co-axial outer and inner sleeve assemblies <NUM> and <NUM> having respective outer and inner resecting windows <NUM> and <NUM> in distal ends thereof, wherein inner sleeve assembly <NUM> carries a first polarity electrode <NUM> therein, and both the outer and inner windows <NUM> and <NUM> have circumferentially spaced-apart cutting edges that comprise second polarity electrodes.

In another aspect of the disclosure, again referring <FIG>, the surgical resecting probe comprises a windowed inner sleeve assembly <NUM> rotatable within a windowed outer sleeve assembly <NUM> wherein a controller 420A and motor drive are adapted to rotate the inner sleeve assembly through window-open and window-closed positions and wherein the controller is adapted to stop motor-driven rotation of the inner sleeve assembly in a selected position wherein the active electrode <NUM> is spaced apart from cutting edges 450a and 450b of the outer sleeve window <NUM> and wherein a return electrode <NUM> is disposed intermediate the electrode <NUM> and the cutting edges 450a and 450b of the outer sleeve window <NUM>.

In another aspect of the disclosure, referring to <FIG> and <FIG>, the resecting probe <NUM> comprises a windowed inner sleeve assembly <NUM> rotatable within a windowed outer sleeve assembly <NUM> wherein a controller and motor drive are adapted to rotate the inner sleeve assembly <NUM> through window-open and window-closed positions, wherein a distal portion of the inner sleeve assembly <NUM> comprises a cylindrical wall defining an outer surface <NUM> and an inner surface <NUM> around an interior channel <NUM> therein (<FIG>) and wherein the interior channel <NUM> is surrounded in part by a first wall <NUM> of the longitudinal dielectric member <NUM> and in part by a second wall <NUM> of the longitudinal metal portion <NUM> and wherein each of the first and second walls <NUM> and <NUM> comprise substantially the full thickness of the cylindrical wall and is not a thin layer of a composite or layered assembly. Again, it should be appreciated that the term second wall <NUM> as used herein describes the wall structure proximal to the window <NUM> which is disposed in the longitudinal metal portion <NUM>.

In <FIG>, it can be seen that the dielectric member <NUM> has a port <NUM> therein that lies under a v-notch <NUM> in the electrode <NUM>. The port <NUM> is adapted for aspiration of fluid therethrough during RF energy delivery which can reduce bubbles from the vicinity of the electrode <NUM> as plasma is formed. Further, <FIG> and <FIG> show ports <NUM> in the distal end housing <NUM> of outer sleeve <NUM> which are adapted to provide fluid flow through the shaft assembly in a window-closed position as shown in <FIG> and <FIG> to maintain a constant fluid outflow as opposed to a fluctuating outflow as would be the case otherwise with the inner sleeve assembly <NUM> rotating at high RPM through window-open and window-closed positions.

Now turning to <FIG>, another variation of a probe working end <NUM> is shown, and more particularly the distal end of the inner sleeve assembly <NUM>' is shown in an exploded view and is similar to the embodiment of <FIG>. The variation of <FIG> again includes a longitudinal dielectric body <NUM>' and a longitudinal conductive metal body <NUM>'. This variation differs the previous embodiment shown in <FIG> in that the structure provided for securely coupling the components <NUM>' and <NUM>' together differs. As can be seen in <FIG> and <FIG>, the dielectric component <NUM>' has lateral elements 540a and 540b extending in a part-cylindrical form that are adapted to slide into and engage the inner surfaces <NUM> of walls <NUM> of the metal longitudinal metal body portion <NUM>'. As best can be seen in <FIG>, the lateral elements 540a and 540b of the dielectric member <NUM>' have an outer surface <NUM> with a radius R that matches the inner surface <NUM> and radius R of the metal portion <NUM>'. Thus, it can be understood that by axially sliding and inserting the dielectric member <NUM>' can into the longitudinal opening or channel <NUM> in longitudinal metal portion <NUM>', a secure and durable connection can be provided between the dielectric and metal components <NUM>' and <NUM>'. In <FIG>, the radial angle RA1 of the metal portion <NUM>' and the radial angle RA2 of the dielectric member <NUM>' can be the same as described previously. Additionally, the radial angle RA3 of the surface of the electrode <NUM> is the same as described previously.

In <FIG>, another variation of a working end <NUM> of an inner sleeve assembly <NUM> is provided in an exploded view to illustrate the structural components that are adapted to securely connect the longitudinal dielectric member <NUM> to the longitudinal metal portion <NUM>. In this variation, the lateral edges 624a and 624b of the dielectric member <NUM> do not interlock with the lateral edges 628a and 628b of the metal portion <NUM> or overlap as in the previous variations. As can be seen in <FIG> and <FIG>, the interfaces of the lateral edges of the components <NUM>, <NUM> simply abut one another and are securely fixed to one another by a retaining collar <NUM> that is adapted to fit into an annular notch or recess <NUM> in both the dielectric member <NUM> the metal portion <NUM> to securely hold the components together. As can be understood, the metal retaining collar <NUM> can have a discontinuity or gap <NUM> in its circumference to allow the collar to be tensioned and slipped over the components <NUM> and <NUM> into the recess <NUM>. Thereafter, the gap <NUM> in the collar <NUM> can be welded to thus permanently couple the dielectric and metal components <NUM> and <NUM>.

In the variation shown in <FIG>, it can be seen that an active electrode <NUM> with legs 652a and 652b is similar to the version described previously in <FIG>. In <FIG>, it can be seen that the legs 652a and 652b extend into receiving channels 654a and 654b in the dielectric member <NUM>. The electrical lead <NUM> in <FIG> again has a pad element <NUM> that is received by a recess <NUM> in the dielectric member <NUM> to contact electrical leads <NUM> therein. In this variation, the electrical leads <NUM> in the recess <NUM> are bare to make electrical contact with the pad element <NUM> but are coated with an insulator <NUM> is the location where such leads extend through the dielectric member <NUM> and into contact with the legs 652a and 652b of the electrode <NUM>. In all other respects, the assembly of components in <FIG> functions in the same manner as described previously. In <FIG>, it can be seen that the radial angles RA1, RA2 of the walls of the metal member <NUM> and dielectric member <NUM> can be the same as described previously. Additionally, the radial angle RA3 of the surface of the electrode <NUM> is the same as described previously.

Now turning to <FIG>, another variation of probe <NUM> is shown with hub <NUM> and shaft <NUM> (see <FIG>) extending about longitudinal axis <NUM> to a working end <NUM> shown in <FIG> shows a distal portion of the outer sleeve assembly <NUM> and bore <NUM> therein together with inner sleeve assembly <NUM>. <FIG> shows the inner sleeve assembly <NUM> from a different angle to better illustrate the electrical lead <NUM> carried by the inner sleeve. Now turning to <FIG> which is an exploded view of the inner sleeve assembly <NUM>, it can be seen that the longitudinal dielectric member <NUM> is again secured to the longitudinal metal portion <NUM> and coupled to tubular member <NUM> with a retaining collar <NUM>. Such a retaining collar <NUM> used to fix together the dielectric member <NUM> and the metal portion <NUM> can be similar to that described in the embodiment of <FIG>.

Referring to <FIG>, this variation differs from previous embodiments in that the electrical lead <NUM> extends through a recess <NUM> in the dielectric member <NUM> and couples to a leg <NUM> of the active electrode <NUM>. The electrical lead <NUM> is not carried on an exterior surface of tubular member <NUM>. Instead, the electrical lead <NUM> extends to the active electrode <NUM> through the interior bore <NUM> of the tubular member. As can be seen in <FIG>, the electrical lead <NUM> extends in the proximal direction from the electrode <NUM> and is flexed at bend <NUM> to enter the interior bore <NUM> of the inner tubular member <NUM> and in this variation extends through a hypotube <NUM> which is coupled to the wall of the tubular member <NUM>. It can be seen that a slot <NUM> is provided in the wall of and tubular member <NUM> which allows for welding the hypotube <NUM> to the interior surface of bore <NUM> in the tubular member <NUM>. At least one similar slot (not shown) can be provided along the length of the tubular member <NUM> to secure the hypotube <NUM> in place. It has been found that is important to carry the electrical lead <NUM> within the interior bore <NUM> of the tubular member <NUM> to protect it from potential damage. In the previous embodiments, for example the version of <FIG>, the electrical lead <NUM> extended in a flat surface <NUM> along the outer surface of the inner tubular member <NUM> and was then covered with insulator layer <NUM>. In the previous embodiment of <FIG>, since the shaft <NUM> of the probe <NUM> (<FIG>) could be torqued and bent significantly during a procedure, high-speed rotation of the inner sleeve assembly <NUM> had the potential of abrading and degrading the insulator sleeve <NUM> overlying the electrical lead <NUM> which could cause an electrical short. Therefore, one aspect of the disclosure as shown in <FIG> includes carrying the electrical lead <NUM> in the interior bore <NUM> of the metal tubular member <NUM> to insure that bending or torque on the shaft <NUM> while operating the inner sleeve assembly <NUM> at high RPM cannot damage the electrical lead <NUM>. <FIG> and <FIG> also show an annular bushing <NUM> that is adapted to cover the recess <NUM> that is filled with potting material as described previously. Referring again to <FIG>, a heat shrink insulator sleeve <NUM> covering the tubular member <NUM> and the at least a portion of the bushing <NUM>. Thus, in high speed rotation, the insulator sleeve <NUM> and bushing <NUM> are the bearing surfaces of the inner sleeve assembly <NUM> as it rotates in the outer sleeve <NUM>.

It can be appreciated from <FIG> that the inner tubular member <NUM> and the hypotube <NUM> comprise a return electrode <NUM> with conductive saline flowing through the interior channel <NUM> of the tubular member <NUM>. Thus, obviously the electrical lead <NUM> carries its own substantial insulation layer on it surface. In one variation, the electrical lead <NUM> is a copper wire instead of a stainless steel wire since such a stainless steel wire would be resistively heated. Preferably, the electrical lead <NUM> is of a material that will not be resistively heated as this would heat saline outflows traveling through the channel <NUM> which would then elevate the temperature of the handpiece which is undesirable.

Now turning to <FIG>, a perspective view and a cut-away view of the hub <NUM> are shown. <FIG> is an enlarged cut-away view of an interior portion of the hub <NUM>. As can be seen in <FIG> and <FIG>, the hypotube <NUM> carries the electrical lead <NUM> that extends through the inner tubular member <NUM>. As can be seen in <FIG>, the tubular member <NUM> extends through the hub <NUM> and the hypotube <NUM> has a proximal end <NUM> in the interior of the hub. The proximal end portion <NUM> of the electrical lead <NUM> is curved outwardly through a slot <NUM> in the tubular member <NUM> and then extends in an interface <NUM> between two polymer collars <NUM> and <NUM> that together provide a seal over and around the insulation layer on the electrical lead <NUM>. Thereafter, a heat shrink material <NUM> such as FEP can disposed over the collars <NUM> and <NUM> (<FIG>). In <FIG> and <FIG>, it can be seen that a polymeric coupling sleeve <NUM> is fixed to the proximal end portion <NUM> of the tubular member that extends proximally to the drive coupler <NUM> which is adapted for coupling to the motor drive of the handpiece (not shown). <FIG> and <FIG> further show conductive metal contact ring <NUM> is disposed over the insulative coupling sleeve <NUM>. As can be seen in <FIG>, on the proximal side of the contact ring <NUM>, another polymeric collar <NUM> is shown that again is covered with an FEP or other heat shrink material. Still referring to <FIG>, the proximalmost end <NUM> of electrical lead <NUM> with its insulator layer removed is in contact with and electrically coupled to the rotating contact ring <NUM>. In turn, the contact ring <NUM> interfaces with spring-loaded ball contacts 780a and 780b in the handpiece (not shown) to carry RF current to from RF source 720B to the active electrode <NUM> (<FIG>). Spring-loaded ball contacts 782a and 782b in the hub are adapted to carry current to or from the outer sleeve assembly <NUM> which comprises a return electrode. It should be appreciated that conductive fluid can migrate into various parts of the hub <NUM> and it is necessary to prevent any migration of conductive fluid into the interface between the spring-loaded ball contacts 780a and 780b and the rotating contact ring <NUM>. Any migrating conductive fluid is effectively a return electrode and could cause a short circuit. To insure that there is no migration conductive fluid into contact with contact ring <NUM>, <FIG> and <FIG> illustrate a flexible seal <NUM> that has is flexible annular sealing elements 788a and 788b that are both proximal and distal from the rotating contact ring <NUM>. By the means, the chamber <NUM> in which the spring-loaded ball contacts 780a and 780b engage the contact ring <NUM> will remain fluid-tight.

Now turning to <FIG>, an arthroscopic tool <NUM> according to the invention is shown which again has a proximal hub <NUM> coupled to an elongated shaft assembly <NUM> that extends about central longitudinal axis <NUM>. The shaft assembly <NUM> includes an outer sleeve <NUM> with bore <NUM> and a co-axial inner sleeve assembly <NUM> that rotates in outer sleeve bore <NUM> and extends to the working end <NUM> of the inner sleeve assembly <NUM>. The hub <NUM> again is adapted for coupling to a handpiece and motor drive controlled by a controller 420A, RF source 420B and negative pressure source 420C as described previously. The controller 420A again includes algorithms for rotating the inner sleeve assembly <NUM> at selected RPMs as well as for stopping the inner sleeve <NUM> in a selected rotational position relative to the outer sleeve <NUM>.

In this variation, referring to <FIG>, the bore <NUM> of the outer sleeve <NUM> extends to a distal open end or opening <NUM> that includes teeth or serrations <NUM> along lateral edges of the opening. Referring to <FIG>, the inner sleeve assembly <NUM> extends to its working end <NUM> which in part comprises a cutter or burr <NUM> with sharp edges <NUM> adapted for cutting hard tissue. The plurality of cutting edges <NUM> can range in number from <NUM> to <NUM>, and often the burr <NUM> from <NUM> to <NUM> cutting edges. The working end <NUM> further includes a cutting window <NUM> with sharp cutting edges that include teeth <NUM> (see <FIG>).

The working end <NUM> and burr <NUM> as can be seen in <FIG>, <FIG> is similar to the distal end portion <NUM> of the inner sleeve assembly <NUM> of <FIG> in that the distal end <NUM> and burr <NUM> comprise a housing <NUM> that is a combination of a longitudinal ceramic or dielectric member <NUM> coupled to a longitudinal conductive metal member <NUM> that carries the sharp edges <NUM>. The dielectric member <NUM> can be a suitable ceramic or glass material and the longitudinal conductive metal member <NUM> typically is stainless steel. When assembled, the dielectric member <NUM> and longitudinal metal member <NUM> have outer surfaces that contact one another along interface <NUM> which is described in more detail below.

Referring again to <FIG> and <FIG>, the longitudinal ceramic member <NUM> carries an active electrode <NUM> in its outer surface, which may be termed a first polarity electrode herein. For convenience, the side of the distal end <NUM> that carries electrode <NUM> is called the electrode side ES and the opposing side configured with window <NUM> and cutting edges <NUM> is called the cutting side CS.

As can be best understood from <FIG>, the longitudinal conductive metal member <NUM> comprises a return electrode <NUM> (which may be termed a second polarity electrode herein) which cooperates with the first polarity or active electrode <NUM> to deliver energy to tissue. The active and return electrodes <NUM> and <NUM> are operatively coupled to RF source 420B and controller 420A as described above. Referring to <FIG> and <FIG>, the outer sleeve <NUM> comprises a conductive metal such as stainless steel with bore <NUM> therein that extends proximally to the hub <NUM> and distally to the distal end opening <NUM>. In <FIG>, it can be seen that the inner sleeve assembly <NUM> comprises a co-axial conductive metal inner tubular member <NUM> that extends proximally to hub <NUM> (<FIG>) and extends distally to couple to the burr <NUM> or housing <NUM> which consists of the longitudinal dielectric member <NUM> and the longitudinal metal member <NUM>. A heat shrink material <NUM> such as FEP is disposed over the inner sleeve and collar <NUM> described below (<FIG>). The metal inner tubular sleeve <NUM> rotates in bore <NUM> of the outer sleeve <NUM>.

Now turning to <FIG>, the inner sleeve assembly <NUM> is shown in exploded view separated from outer sleeve <NUM> with the electrode side ES facing upward and the cutting side CS facing downward. In <FIG>, it can be seen that the longitudinal metal member <NUM> comprises a body that circumferentially extends greater than <NUM>° around axis <NUM> and interior passageway <NUM> such that the metal member <NUM> provides the burr <NUM> with sufficient strength for cutting hard tissue at high RPMs. In this variation, the longitudinal metal member <NUM> is fabricated by welding together a proximal element 866a and a distal burr element 866b. The cutting edges <NUM> extend longitudinally over the length of the burr <NUM> and distally around distal tip <NUM> thereof (see also <FIG>). As can be understood, the longitudinal dielectric member <NUM> is thus protected from high stresses on the burr cutting edges <NUM> and cutting edges of window <NUM> when cutting tissue such as bone at high RPMs. In this variation, the lateral edges 872a and 872b of the dielectric member <NUM> interface with the lateral edges 874a and 874b of the metal member <NUM> and are securely fixed together by a retaining collar <NUM> that fits tightly over reduced diameter annular portion or notch <NUM> of the dielectric member <NUM> and the metal member <NUM> to securely hold the components together. The metal retaining collar <NUM> has a discontinuity <NUM> in its circumference to allow the collar to be tensioned and slipped over the components <NUM> and <NUM> and then welded.

Referring to <FIG>, the proximal reduced diameter portion <NUM> of the longitudinal metal member <NUM> is dimensioned for insertion into the bore <NUM> of the thin wall tubular sleeve <NUM> to form the structural components of the inner sleeve assembly <NUM>. It can be understood how the tubular sleeve <NUM> with bore <NUM> therein slides over and engages the proximal portion <NUM> to the metal member <NUM> to provide a durable connection.

Still referring to <FIG>, the electrical connection to the active electrode <NUM> can be seen. The electrical lead <NUM> in phantom view extends to the active electrode <NUM> through a hypotube <NUM> which is coupled to the inner wall of the tubular member <NUM>. The electrical lead then can extend through a recess <NUM> in the dielectric member <NUM> to a channel <NUM> in the dielectric member to couple to a leg <NUM> of the active electrode <NUM>. The proximal end (not shown) of the electrical lead <NUM> extends into a hub <NUM> (cf. <FIG>) as described previously to connect to electrical contacts in a handle which allows for rotation of the inner sleeve assembly <NUM> and for coupling electrical energy to the electrical lead <NUM>.

Referring to <FIG>, the longitudinal dielectric member <NUM> together with the longitudinal metal member <NUM> form a wall around an interior channel <NUM> therein that communicates within bore <NUM> in the inner tubular member <NUM> and a negative pressure source 420C for aspirating tissue chips and fluid from a working space as is known in the art. In one variation shown in <FIG>, the metal wall portion <NUM> (disregarding the opening of window <NUM> therein) extends radially around axis <NUM> and the interior channel <NUM> in a radial angle RA4' of at least <NUM>°, and often will extend radially around the interior channel <NUM> in a radial angle RA4' of at least <NUM>°. When describing the metal wall portion <NUM> herein that extends in a radial angle indicated at RA4' in <FIG>, it is meant to refer to the metal wall in a transverse section which is proximal or distal to window <NUM>, where such a wall portion provides the required hoop strength to the metal member <NUM>. Further, referring to <FIG> and <FIG>, the dome-shaped electrode <NUM> has a surface that extends radially around the axis <NUM> in a radial angle RA1' of at least <NUM>° or at least <NUM>°. As described previously, the lateral electrode edges are spaced apart from the closest portion of metal member <NUM> or the outer sleeve opening <NUM> (i.e., teeth <NUM>) by a radial angle RA2' of at least <NUM>° (see <FIG>). In one variation, the radial angle RA1' of the surface of electrode <NUM> is <NUM>° and minimum distance of lateral edges of electrode <NUM> from the closest return electrode has a radial angle RA2' of <NUM>°.

Referring to <FIG>, <FIG> and <FIG>, the superior surface of the outer sleeve <NUM> at the edge of distal opening <NUM> is configured with a slope or chamfer <NUM> that allows the working end of the device to be positioned closely to targeted tissue. In one variation, as shown in <FIG>, the wall thickness Z of the superior wall at the opening edge is less than <NUM>% of the full wall thickness and often less than <NUM>% of the full wall thickness. <FIG> is a side view of the working end of the cutting device <NUM> showing that the distal surfaces of the cutting edges <NUM> of the burr <NUM> extend distally beyond the dielectric member <NUM> by dimension AA which is at least <NUM>" or at least <NUM>" which protects the ceramic when cutting hard tissue. In one variation, dimension AA is <NUM>". <FIG> further shows that the distal surfaces of the cutting edges <NUM> of burr <NUM> extend distally beyond the distalmost tip <NUM> of the outer sleeve by dimension BB which is at least <NUM>" or at least <NUM>" which allows for effective cutting into hard tissue with the tip of the burr <NUM>.

Referring to <FIG> and <FIG>, it can be seen that the outer sleeve <NUM> and teeth <NUM> extend around the axis <NUM> in a radial angle greater that <NUM>° and in one variation the radial angle is greater than <NUM>° at the distalmost teeth <NUM>. As can be understood, during use of the probe, the teeth <NUM> of the outer sleeve <NUM> may engage tissue which can tend to flex or flare the teeth <NUM> outward and away from the rotating inner sleeve assembly <NUM> which is undesirable as tissue could be trapped between the outer sleeve <NUM> and the working <NUM> of the inner sleeve assembly <NUM>. For this reason, at least the distal portion of outer sleeve <NUM> must be a very hard alloy to resist such flaring or flexing, and has a hardness of at least Rockwell C50 or at least Rockwell C60. In one variation, the material is a <NUM> stainless steel or a 465SS or a 420SS. In one variation, the diameter of the outer sleeve <NUM> is <NUM>" with a wall thickness of <NUM>".

As described in previous embodiments, a stopping mechanism is controlled by the controller 420A that is adapted to stop rotation of inner sleeve assembly <NUM> in a particular rotational position, for example, with the electrode side ES facing upwardly as in <FIG>. In general, it can be understood that the devices of the disclosure described above are adapted to function in two different operational modes. First, the working end of the probe <NUM> of <FIG> utilizes high-speed rotation of the inner sleeve assembly <NUM> to cut and remove tissue. Second, the controller 420A can stop rotation of the inner sleeve assembly <NUM> so that the active electrode <NUM> is exposed and thereafter the electrode arrangement can be energized to coagulate or ablate tissue, depending on wave form and power delivered.

In another aspect of the disclosure, a third mode of operation is provided and consists of contemporaneous rotation of the inner sleeve assembly <NUM> together with activation of the active electrode <NUM>. This mode of operation can thereby cut and remove tissue at the same time as coagulating or ablating tissue with RF energy. In this third mode of operation, it is necessary to sequence the activation of RF energy to the active electrode <NUM> during each <NUM>° rotation of the inner sleeve assembly <NUM> so that the active electrode <NUM>, effectively, does not form a short circuit with the return electrode <NUM> of the outer sleeve <NUM>. In one variation, micro-switches can be provided in the proximal hub of the probe to turn RF energy delivery on and off during each rotation of the inner sleeve assembly. However, such micro switches or other similar encoding mechanisms may that operate instantaneously and effectively during high-speed rotation.

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 openended 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. 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.

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.

Claim 1:
An arthroscopic cutter, comprising:
an elongated outer sleeve (<NUM>) extending about a longitudinal axis (<NUM>) with an interior bore (<NUM>) having an open distal end (<NUM>);
an inner sleeve (<NUM>) configured to rotate in the bore (<NUM>) in the outer sleeve (<NUM>) wherein the inner sleeve (<NUM>) carries a distal housing (<NUM>) having a longitudinal metal member (<NUM>) and a longitudinal ceramic member (<NUM>) that respectively form longitudinal-extending sides of the housing around an inner channel that communicates with a negative pressure source (420C); and
an electrode (<NUM>) disposed in an outer surface of the ceramic member (<NUM>) characterized in that the metal member (<NUM>) has a proximal portion (866a) with a window (<NUM>) therein configured with circumferentially spaced apart lateral edges adapted for cutting tissue and the metal member (<NUM>) has a distal portion (866b) with sharp cutting edges (<NUM>) extending around sides and a distal tip of the metal member (<NUM>).