Patent Description:
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 hand piece and a selection of interchangeable tool probes have 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.

For example, such endoscopic tool systems may have tool probes which combine a rotatable cutter and a radiofrequency electrode suitable for ablation and/or coagulation. When operating in a cutting mode, a negative pressure is typically applied to the probe to draw tissue into a cutting window and thereafter suction tissue chips out through an extraction channel. When operating in an electrosurgical mode, in contrast, there typically would be no negative pressure applied and no fluid flow through the probe.

While the combination tool of the invention with both a rotatable cutter and an RF electrode provides a significant advantage, in some such designs, there is a need to cool the probe and/or hand piece when operating in the electrosurgical mode.

It is therefore an object of the present invention to provide improved surgical systems, such as improved arthroscopic tissue cutting and removal systems of the type which combine a rotatable mechanical cutter and a radiofrequency electrode suitable for ablation and/or coagulation. In particular, it would be advantageous to provide such a tissue cutting and removal system with a rotatable cutter and a radiofrequency electrode having an improved cooling function when operating in the electrosurgical mode. At least some of these objectives will be met by the inventions described herein.

Description of the Background Art. Relevant commonly owned patents and applications include <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; <NUM>,<NUM>,<NUM>; and copending applications <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM>,<NUM>; <NUM>/<NUM><NUM>.

<CIT> describes a medical device that includes an elongated sleeve having a longitudinal axis, a proximal end and a distal end. A cutting member having sharp edges formed from a wear-resistant ceramic material is carried at the distal end of the elongated sleeve. A motor drive is coupled to the proximal end of the elongated sleeve to rotate the sleeve and cutting member at high speed to cut bone and other hard tissue. An electrode is carried in a surface portion of ceramic cutting member for cautery or radiofrequency ablation of tissue when the sleeve and cutting member are in a stationary position.

Methods of surgery described here below are not part of the claimed invention. Disclosed herein are improved apparatus and methods for resecting and otherwise treating tissue. Such apparatus and methods provide endoscopic tools for both mechanical resection and electrosurgical treatment, such as ablation and coagulation. The endosurgical tools also referred to as probes and resecting probes, will typically but not necessarily comprise a reusable handle and a removable or detachable probe shaft, where the probe shaft includes both a cutting function and an electrosurgical function. The probe shaft will be configured to allow for fluid aspiration during both cutting and electrosurgical operation, where the fluid flow provides cooling during the electrosurgical operation.

In a first aspect, the present disclosure provides a resecting probe comprising a shaft assembly and a motor drive. The shaft assembly includes (i) an outer sleeve having an axial bore and an outer window in a distal side thereof and (ii) an inner sleeve having an axial extraction channel configured to connect to a negative pressure source (typically for aspiration of tissue chips or debris as described further below) and an inner window in a distal side thereof. The inner sleeve is rotationally disposed in the axial bore of the outer sleeve which allows the inner sleeve window to rotate relative to the outer sleeve window to thereby cut tissue. The inner sleeve is typically motor-driven to cut tissue that is drawn into the windows and aspiration is applied to draw fluid and tissue debris through the extraction channel. The shaft assembly is further configured to form a flow aperture in a distal portion thereof when the inner cutting window and the outer cutting window are out of alignment, allowing a cooling fluid flow through the shaft assembled (and optionally a handpiece as described hereinafter) during electrosurgical use when the cutting windows are not aligned, blocking the tissue debris aspiration flow path. An electrode is carried on the inner sleeve, and the motor drive is coupled to rotate the inner sleeve relative to the outer sleeve.

The flow aperture can be formed in a variety of ways. For example, according to the invention, an outer sleeve aperture may be formed in a wall of the outer sleeve, wherein such outer sleeve aperture aligns with the inner window when the inner sleeve is in a stop position. Typically, the outer sleeve aperture comprises a plurality of slots formed in the wall of the outer sleeve, and fluid may flow into the extraction channel to provide a cooling function while tissue and other debris is blocked by the configuration of the slots. Alternatively, not according to the invention, such apertures or slots may be formed in a wall of the inner sleeve, wherein such inner sleeve apertures align with the outer window when the inner sleeve is in the stop position. The inner sleeve apertures typically comprise a plurality of slots formed in the wall of the inner sleeve to serve a function similar to that described previously.

In preferred embodiments, a controller is coupled to the motor drive and configured to control rotation of the inner sleeve and to stop rotation of the inner sleeve in a stop position where the outer and inner windows are out of alignment, alternately called a window-closed position. The controller will typically be further configured to deliver energy to the electrode when the inner sleeve is in the stop position. The resecting probe will usually further comprise an aspiration source coupled to the extraction channel in the inner sleeve to draw tissue through the outer and inner windows when said windows are at least partially rotationally aligned, and the controller will often be further configured to operate in a first mode wherein both (i) the aspiration source draws fluid and tissue into said windows when at least partially aligned, and (ii) the motor drive rotates the inner sleeve to resect tissue. The controller may be further configured to operate in a second mode wherein (i) the aspiration source draws fluid through the flow aperture and inner window in said stop position, and (ii) the electrode is activated to apply energy to tissue.

Exemplary structural and operating parameters include adjusting the aspiration source to draw fluid through the flow-restricted aperture at a rate of at least <NUM>/min to enhance cooling of the probe and cooling of fluid in the working space. The flow apertures usually have dimensions selected to inhibit tissue from being aspirated therethrough, i.e., the apertures may act as a filter, typically comprising one or more elongated slots. The elongated slot typically has a width ranging from <NUM>,<NUM> to <NUM>,<NUM> (<NUM>" to <NUM>").

In other specific aspects of the resecting probe, the inner window is formed within a ceramic portion of the inner sleeve and the electrode is carried by a ceramic portion of the inner sleeve. A ceramic cutting tip may be carried at a distal end in the inner sleeve, and the electrode may be carried on a side of the ceramic cutting tip. In some instances, the ceramic cutting tip is fluted and the electrode is disposed between adjacent flutes.

In a second aspect, which is not part of the claimed invention, the present disclosure provides methods for treating tissue in a fluid-filled working space. Such methods comprise providing a probe including (i) an outer sleeve having an axial bore and an outer window in a distal side thereof and (ii) an inner sleeve configured to rotate in the axial bore of the outer sleeve and having an axial extraction channel and an inner window in a distal side thereof. The inner window is rotated in and out of alignment with the outer window as the inner sleeve rotates, and the sleeves are configured to form flow apertures in a distal portion thereof when the inner cutting window and the outer cutting window are out of alignment. A distal end of the probe is urged against a target tissue, and a negative pressure is applied through the extraction channel. The inner sleeve is rotated to resect tissue which is drawn through the outer window and the inner window when the windows are aligned as they rotate. The inner sleeve may be stopped in a stop position in which said outer and inner windows are not rotationally aligned, and an electrode carried by the inner sleeve may be activated, typically by applying radiofrequency (RF) current to treat tissue while actuating the aspiration source to draws fluid through the flow apertures to thereby cool the probe and fluid in the working space.

In particular examples, operating in a first mode comprise (i) controlling a motor drive to rotate the inner sleeve, and (ii) actuating an aspiration source to apply a negative pressure through the extraction channel. Typically, such a first mode includes operating the aspiration source to draw fluid through the windows at a rate of at least <NUM>/min. A second operating mode may comprise (i) stopping the inner sleeve in the stop position, (ii) actuating the aspiration source, and (iii) activating the electrode. In specific examples, operating the aspiration source draws fluid through the flow aperture at a rate of at least <NUM>/min.

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.

The present disclosure 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 hand piece 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 invention provides a hand piece <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 hand piece <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> titled ARTHROSCOPIC DEVICES AND METHODS.

As can be seen in <FIG>, the probe <NUM> is shown in two orientations for detachable coupling to the hand piece <NUM>. More particularly, the hub <NUM> can be coupled to the hand piece <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 hand piece <NUM> to allow the physician to interface the cutting member <NUM> with targeted tissue in all directions without having to manipulate the hand piece 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 hand piece for displaying operating parameters, such as cutting member RPM, mode of operation, etc..

It can be understood from <FIG> that the system <NUM> and hand piece <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>
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> 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> 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> 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 hand piece <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 hand piece <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 hand piece <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 hand piece <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 hand piece <NUM> in an upward or downward orientation relative to the hand piece, 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 hand piece <NUM> carries a first Hall effect sensor <NUM> in a distal region of the hand piece <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 hand piece <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 hand piece, (ii) the upward or downward orientation of the probe hub <NUM> relative to the hand piece <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 hand piece <NUM> is in axial alignment with either magnet 250a or 250b when the probe hub <NUM> is coupled to hand piece <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 hand piece <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 hand piece 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 hand piece 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 invention, 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 invention, 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 pre-selected 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 the Hall sensor <NUM> can sense lessening of magnetic field strength as a magnet 255a or 255b in the 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 hand piece <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 invention, the drive coupling <NUM> and thus magnets 255a and 255b are attached to inner sleeve <NUM> and cutting member <NUM> in a predetermined 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 invention 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 reactivated 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. pdf and http://literature. rockwellautomation. com/idc/groups/literature/documents/wp/drives-wp004_-en-p. 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 <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 hand piece <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 hand piece with a motor drive, a controller, and a probe with a proximal hub configured for detachable coupling to the hand piece, 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 hand piece, activating the motor drive to thereby rotate the drive coupling and magnets at least <NUM>°, using a hand piece 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 invention 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 hand piece <NUM> and Hall affect sensors <NUM> and <NUM> are of course the same as described above as there is no change in the hand piece <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> and <FIG>, the working end <NUM> of another variation of the arthroscopic shaver is shown which is similar to that of <FIG>, <FIG> and <FIG> which includes an inner sleeve <NUM> that carries a distal ceramic cutting body or cutter <NUM> adapted for rotation at high speeds in an axial bore <NUM> in a windowed metal outer sleeve <NUM>. <FIG> shows the outer sleeve <NUM> in a rotational position in which the outer sleeve window <NUM> in a first side <NUM> of outer sleeve <NUM> is facing upwardly with teeth <NUM> along the edges of the window <NUM>. The inner sleeve <NUM> and the ceramic cutter <NUM> are rotated to a position wherein a window <NUM> in the cutter <NUM> is facing downward and is not exposed in window <NUM> of the outer sleeve <NUM>. <FIG> shows the entire working end <NUM> rotated <NUM>° to a position wherein a second side <NUM> of the outer sleeve is facing upwardly. As described in previous embodiments, the rotating ceramic cutter <NUM> can be stopped in the position shown in both <FIG> by a stop algorithm to thereby expose the active electrode <NUM> carried by the ceramic cutter <NUM> aligned generally with the centerline <NUM> of window <NUM> in the outer sleeve <NUM> as can be seen best in <FIG>. With the electrode <NUM> in the position shown in <FIG>, the physician can energize the active electrode <NUM> in connection with return electrode <NUM>, which consists of a portion of outer sleeve <NUM> and ablate or coagulate tissue by translating the electrode <NUM> over a targeted tissue surface.

When using the electrode <NUM> to delivery energy to tissue, it can be easily understood that the saline distention fluid in the vicinity of energized electrode is heated by the energy delivery. It has been found that it is desirable to provide for a controlled fluid outflow through the working end <NUM> when the windows <NUM> and <NUM> of the respective outer sleeve <NUM> and inner sleeve or ceramic cutter <NUM> are not aligned as in <FIG>. Such a continuous fluid flow provided by the negative pressure source <NUM> will then extract heated distention fluid from the working space which can be important. Thus, as can be seen in <FIG>, at least one outflow aperture or flow aperture <NUM> is provided in the second side <NUM> of the outer sleeve <NUM>. In a variation, referring to <FIG>, a plurality of elongated, narrow slots <NUM> are provided for such a fluid outflow.

<FIG> is a longitudinal sectional view of the working end <NUM> of <FIG> and shows the fluid flow through the slots <NUM> into central channel <NUM> of the ceramic cutter <NUM>. In this variation, the slots are narrow and have a length that approximates that of window <NUM> in the ceramic cutter <NUM> through which the fluid flows into the central channel <NUM> and extraction channel <NUM> that extends through the probe (see <FIG>). The width W of the slots <NUM> can range from <NUM>,<NUM> to <NUM>,<NUM> (<NUM>" to <NUM>") and the number of slots can range from <NUM> to <NUM> or more (<FIG>). It has been found that narrow slots are preferable over larger openings to allow such fluid outflows as the narrow slots prevent tissue debris from entering the slots. The total area of the slots for such outflows can be configured to provide a continuous flow in the range of <NUM>/min to <NUM>/min. In another variation, a plurality of round or oval apertures could be used instead of the elongated slots, wherein each such aperture has a cross-section ranging from <NUM>,<NUM> to <NUM>,<NUM> (<NUM>" to <NUM>"). In another aspect of the invention, referring to <FIG>, it can be seen that the cross-section of the outflow pathway increases from central channel <NUM> in the ceramic cutter <NUM> to the larger extraction channel <NUM> in the inner sleeve <NUM> which communicates with the negative pressure source. Such an increase in cross section of the fluid outflow pathway in the proximal direction assists in preventing clogs as any extracted tissue or bone chips are more effectively floating and entrained in the fluid outflow.

Now turning to <FIG>, the working end <NUM> of another variation of the arthroscopic shaver is shown which is similar to that of <FIG>. The ceramic cutting body or cutter <NUM> that rotates in the metal outer sleeve <NUM>. 11A shows the ceramic cutter in a rotational position in which the window <NUM> in a first side <NUM> of the cutter <NUM> is aligned with the window <NUM> in the outer sleeve <NUM>. 11B shows the ceramic cutter <NUM> rotated <NUM>° to a position wherein a second side <NUM> of the ceramic cutter <NUM> is exposed in the window <NUM> of the outer sleeve <NUM>. As described previously, the ceramic cutter <NUM> can be stopped in the position shown in FIG. 11B by the controller's stop algorithm to thereby expose an active electrode <NUM>. The physician then can energize the active electrode <NUM> to ablate or coagulate tissue. In this variation, the second side <NUM> of the ceramic cutter <NUM> is configured with at least one elongated slot <NUM> which are configured to allow fluid flow through the slots <NUM>. Thus, this configuration provides fluid flows through the working end <NUM> to cool a distention fluid in the working space similar to that of the working end of <FIG>, except the slots or slots <NUM> are in the ceramic cutter <NUM> instead of the outer sleeve.

In general, a resecting probe for operating in a fluid-filled working space is provided which comprises a shaft assembly including (i) an outer sleeve having an outer window in a distal first surface and a flow aperture in a second surface that is opposed to the first surface; and (ii) an inner sleeve with a inner cutting window rotationally disposed in a bore of the outer sleeve, an aspiration source coupled to a lumen in the inner sleeve adapted to draw tissue into the outer and inner windows when said windows are at least partially rotationally aligned, a motor drive for rotating the inner sleeve and a controller configured for stopping rotation of the inner sleeve in a stop position in which said outer and inner windows are not rotationally aligned, and an electrode carried by a distal end of the inner sleeve configured for delivering energy to tissue when the inner sleeve is in said stop position. Such a tissue resecting probe further includes a controller that is adapted to operate in a first mode in which (i) the aspiration source draws fluid and tissue into said windows when at least partially aligned, and (ii) the motor drive rotates the inner sleeve to resect tissue. Further, such a tissue resecting probe has a controller adapted to operate in a second mode in which (i) the aspiration source draws fluid through the flow aperture and inner window in said stop position, and (ii) the electrode is activated to apply energy to tissue.

A method corresponding to the invention comprises providing a probe with an elongated shaft assembly including (i) an outer sleeve having an outer window in a distal first surface and a flow aperture in a second surface that is opposed to the first surface, and (ii) an inner sleeve with an inner window rotationally disposed in a bore of the outer sleeve, rotating the inner sleeve to thereby resect tissue while actuating an aspiration source coupled to a lumen in the inner sleeve, stopping the inner sleeve in a stop position in which said outer and inner windows are not rotationally aligned and activating an electrode carried by the inner sleeve to treat tissue while actuating the aspiration source to draws fluid through the flow aperture to thereby cool the probe.

In this method, a controller operates in a first mode to (i) control a motor drive to rotate the inner sleeve and (ii) actuate the aspiration source. Thereafter, the controller operates in a second mode to (i) stop the inner sleeve in the stop position, (ii) actuate the aspiration source, and (iii) energize the electrode to ablate or cauterize tissue.

Now turning back to <FIG>, another aspect of the invention relating to the working end <NUM> and ceramic cutter <NUM> is shown. As previously described, the inner sleeve <NUM> and ceramic cutter <NUM> are adapted to rotate in bore <NUM> of the outer sleeve <NUM>. The distal region of the ceramic cutter <NUM> includes burr edges <NUM> which are configured for cutting bone. For such bone cutting, the motor drive is adapted to rotate the ceramic cutter <NUM> at very high speeds, for example from <NUM>,<NUM> to <NUM>,<NUM> RPM. As can be seen in <FIG>, the inner sleeve <NUM> is electrically conductive and functions to carry RF current from RF source <NUM> to the active electrode <NUM> by electrical lead <NUM> indicated schematically in <FIG>. As described previously, still referring to <FIG>, the outer sleeve <NUM> functions as a return electrode <NUM>. For this reason, the inner sleeve <NUM> is covered with an insulator layer <NUM> which can be an insulative heat shrink polymer, for example, FEP, PTFE or the like. The inner sleeve assembly which includes inner sleeve <NUM> and ceramic cutter <NUM> as shown in <FIG> includes several features that insure durability and electrosurgical functionality. In one aspect, the insulator layer <NUM> is adapted to cover the distal end <NUM> of the inner sleeve <NUM> and overlap a portion <NUM> of the ceramic cutter <NUM>. Such an overlap is at least <NUM>" and preferably greater than <NUM>" and is important to insure that there is no possibility of electrical shorting between the inner sleeve <NUM> and outer sleeve <NUM> which are immersed in a saline environment. In a second aspect, the ceramic cutter <NUM> has a body surface <NUM> with an outer diameter that is dimensioned for a snug rotating fit in bore <NUM> of the outer sleeve <NUM>. Further, it can be seen that a gap indicated at G is provided between the outer surface <NUM> of the insulator layer <NUM> and the bore <NUM> of outer sleeve <NUM>. It can be understood that under high rotational speeds, it is necessary to insure that the outer surface <NUM> of insulator <NUM> doe not contact the outer sleeve <NUM> which would cause immediate wear on the polymer insulator layer <NUM>. Thus, the only bearing surface of the inner sleeve assembly comprises the outer body surface <NUM> of the ceramic cutter <NUM> which rotates in the bore <NUM> of outer sleeve <NUM>. The gap G is at least <NUM>,<NUM> (<NUM>") and often greater than <NUM>,<NUM> (<NUM>").

In another aspect of the invention, as can be seen in <FIG> and <FIG>, the proximal faces <NUM> of the burr edges <NUM> closely interface with the distal end <NUM> of the outer sleeve <NUM>. The inner sleeve assembly (inner sleeve <NUM> and ceramic cutter <NUM>) are coupled to a proximal hub assembly (not shown) which is configured to maintain the ceramic cutter <NUM> in an axial position without tolerance between the proximal faces <NUM> of burr edges <NUM> and the distal end <NUM> of outer sleeve <NUM>. In a variation, the gap indicated GG is less than <NUM>,<NUM> (<NUM>") or less than <NUM>,<NUM> (<NUM>") (<FIG>). Such tight tolerances prevents unwanted stress on both the ceramic cutter <NUM> and outer sleeve <NUM> when the physician may apply substantial sideways pressure on the working end <NUM> and ceramic member <NUM> when cutting bone.

In another aspect of the invention shown in <FIG> and <FIG>, the electrodes <NUM> and <NUM> are configured with a plurality of sharp edges <NUM> that allow for more effective RF current flow from the electrode to tissue. In another aspect, the electrode <NUM> has a substantial surface area, and in a variation, the electrode has a surface area of at least <NUM><NUM> or at least <NUM><NUM>.

<FIG> shows another probe working end <NUM> that illustrates another aspect of the invention. In <FIG>, the ceramic cutter <NUM> carries electrode <NUM> which is similar to the electrodes shown in <FIG> and <FIG>, except the electrode <NUM> includes an additional feature which comprises a radial edge <NUM> that extends outwardly from the flat surface <NUM> of the electrode <NUM>. The radial edge <NUM> extends upward to the height of the burr edge <NUM>. As can be understood from <FIG>, when the ceramic cutter <NUM> rotates in the direction of arrow AA, the burr edges <NUM> will cut bone. When the cutter <NUM> is rotated in this direction (arrow AA), the radial edge <NUM> of electrode <NUM> will be on the trailing edge of the burr and will not interfere with bone cutting. However, when the physician actuates the controller to operate the motor drive to rotate the ceramic cutter <NUM> in the direction of arrow BB, the radial edge <NUM> of electrode <NUM> will engage tissue as it rotates since the edge extends radially outward from the flat surface <NUM> the electrode <NUM>. While the active electrode <NUM> has been described previously being used in a stationary position to ablate or coagulate tissue, it has been found that it is also useful to rotate the energized electrode <NUM> in direction BB. When rotating the energized electrode <NUM>, the radial edge <NUM> of electrode <NUM> can then simultaneously cut and ablate or coagulate tissue. In other words, the radial edge <NUM> of the electrode <NUM> then uses both mechanical and electrosurgical energy to remove and ablate or coagulate tissue contemporaneously.

Referring back to <FIG>, it can be seen that the electrode <NUM> is secured to the ceramic cutter <NUM> by a rivet <NUM> shown in phantom view. <FIG> further shows micropores <NUM> in the electrode <NUM> that communicate with passageway <NUM> in the ceramic cutter <NUM> which in turn communicates with the interior channel <NUM> in the cutter <NUM> and negative pressure source <NUM> which can reduce bubbles around the electrode surface when using the energized electrode <NUM>.

Now turning to <FIG>, another variation of an arthroscopic probe is shown that is similar to that of <FIG> in which the RF probe working end <NUM> again includes a windowed outer sleeve <NUM> and a rotatable inner sleeve <NUM> (see <FIG>) that carries a ceramic cutting member <NUM> that rotates in the window <NUM> of the outer sleeve. In this variation, outer sleeve <NUM> is shown be fabricated of a metal such as stainless steel, however, the outer sleeve <NUM> and distal end thereof could also be a ceramic. As can be seen in <FIG>, the distal end portion <NUM> of outer sleeve <NUM> includes side apertures or flow apertures 640A and 640B adjacent the window <NUM> that perform functions as described previously, including cooling the fluid in the working space and cooling the handpiece with continuous fluid flow through the extraction channel.

It should be appreciated that a number of such side apertures in this variation can number from <NUM> to <NUM> or more and are spaced apart from window edges <NUM> such that when the inner sleeve <NUM> is in the window-closed or non-aligned position as shown in <FIG>, the apertures 640A and 640B communicate fully with the interior passageway <NUM> within ceramic cutting member <NUM> and inner sleeve <NUM> such that aspiration from a negative pressure or aspiration source <NUM> (<FIG>) will pull saline through the apertures 640A and 640B.

As described previously, the inner sleeve <NUM> can be stopped in the position shown in <FIG> with the electrode <NUM> fully exposed in window <NUM>. Thereafter the electrode <NUM> can be energized and used for ablating or coagulating tissue. In such a method of use, the energized electrode <NUM> can heat the saline solution in a working space which is undesirable. In this variation, an opening or aperture <NUM> adjacent and beneath the electrode <NUM> is adapted to provide fluid outflows therethrough. However, the volume of fluid aspirated through aperture <NUM> is limited. In such a method of use, the fluid outflow passes through the passageway <NUM> in the inner sleeve <NUM> and also the flow channel <NUM> in hand piece <NUM> (see <FIG>). After a period of continuous use, the energized electrode <NUM> can cause unwanted heating of the handle <NUM> due to an extended period of time in which such heated fluid flows through the probe shaft and handle <NUM> (<FIG>).

In the variation shown in <FIG>, the negative pressure source <NUM> (<FIG>) can aspirate substantially larger volumes of fluid through the apertures 640A and 640B which is advantageous for multiple reasons. In one aspect, the flows through the side apertures 640A, 640B can reduce outflows through the aperture <NUM> which then reduces the chance of fluid flow through aperture <NUM> from extinguishing plasma that is ignited about the electrode <NUM> in a tissue ablation mode. In a second aspect, increased fluid outflows through the side or cooling apertures 640A, 640B can substantially reduce the temperature of fluid in the working space of the joint due to increased fluid inflows into and through the working space. In a third aspect, the continuous outflow through the side apertures 640A, 640B allows the controller algorithm to continuously modulate inflows to match the outflows thus maintaining expansion of the joint cavity. In other words, the continuous inflows and outflows prevent collapse of the joint cavity which often occurs with commercially available probes which start and stop the inflow and outflow pumps based on pressure calculations which result in lag in response time. In a fourth aspect, it has been found that the temperature of handpiece <NUM> (<FIG>) can be cooled significantly, for example, by <NUM>° C. or more when energizing the electrode <NUM> continuously for one minute, which is a reasonable standard for comparing handle temperatures with a previous embodiments without the side apertures. In one variation, the fluid outflow through the side apertures 640A-640B is at least <NUM>/min, at least <NUM>/min, at least <NUM>/min, at least <NUM>/min or at least <NUM>/min. In contrast, the fluid outflow through the aperture <NUM> adjacent the electrode <NUM> is between <NUM>/min and <NUM>/min and more typically between <NUM>/min and <NUM>/min.

<FIG> shows the outer sleeve <NUM> <FIG> with the inner sleeve <NUM> and cutting ceramic cutting member <NUM> removed where it can be seen that the axial length AX of the apertures 640A and 640B is similar to, or at least <NUM>% of, the axial length AX' of the electrode <NUM>. Further, the inner edges 662a and 662b of the apertures 640A and 640B are sharp which provides additional functionality (<FIG>). It can be understood that tissue debris or soft tissue may be suctioned into the side apertures 640A, 640B when the negative pressure source <NUM> is operating and the ceramic cutter <NUM> is being rotated to cut tissue. In such cases, the scissor-like action between cutting edges <NUM> of the ceramic cutter <NUM> (<FIG>) and sharp edges 662a, 662b will cut any tissue drawn into the apertures 640A and 640B. Similarly, if the probe is being used to coagulate or ablate tissue with the electrode <NUM> in a stationary position as shown in <FIG>, then any tissue debris adhered to electrode <NUM> will be cut upon rotation of the ceramic cutting member <NUM> against the inner edges 662a and 662b of the side apertures 640A and 640B.

<FIG> is view of another outer sleeve similar to that of <FIG> having differently shaped side apertures 640A' and 640B' with sharp inner edges <NUM>.

Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration and the above description of the invention is not exhaustive. Specific features of the invention are shown in some drawings and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention. A number of variations and alternatives will be apparent to one having ordinary skills in the art. Such alternatives and variations are intended to be included within the scope of the claims. Particular features that are presented in dependent claims can be combined and fall within the scope of the invention. The invention also encompasses embodiments as if dependent claims were alternatively written in a multiple dependent claim format with reference to other independent claims.

Other variations are within the scope of the present invention as defined in the appended claims. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the scope of the invention, as defined in the appended claims.

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 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.

Claim 1:
A resecting system, comprising:
a resecting probe comprising:
a shaft assembly including (i) an outer sleeve (<NUM>) having an axial bore and an outer cutting window (<NUM>) in a distal side thereof and (ii) an inner sleeve (<NUM>) having an axial extraction channel (<NUM>) configured to connect to a negative pressure source and an inner cutting window in a distal side thereof, said inner sleeve being rotationally disposed in the axial bore of the outer sleeve to allow the inner cutting window to be rotated in and out of alignment with the outer cutting window to cut tissue and to allow tissue and fluid to be drawn through the windows into the extraction channel (<NUM>) when the windows are at least partially aligned;
an electrode (<NUM>) carried on the inner sleeve; and
a motor drive coupled to rotate the inner sleeve (<NUM>) relative to the outer sleeve (<NUM>),
characterized in that at least one flow aperture (640A; 640B) is formed in a wall of the outer sleeve, wherein, when the inner sleeve is in a window-closed position with the inner cutting window out of alignment with the outer cutting window, at least one said flow aperture aligns with the inner cutting window and communicates with the extraction channel (<NUM>) and the electrode is centered within the outer cutting window.