Surgical tool arrangement and surgical cutting accessory for use therewith with the tool arrangement including a toothed cutting edge and a generally straight cutting edge

A surgical tool arrangement for performing endoscopic surgical procedures which includes a powered handpiece and a cutting accessory which detachably connects to the handpiece and incorporates multiple blade configurations or styles into one accessory. The accessory includes a cutting element which rotates within an outer housing element, wherein each element has a cutting window at its distal end, and one of the cutting windows has two sides which have differently configured cutting geometries. One of the cutting windows has a first side with a cutting edge that is toothed and a second side with a cutting edge that is generally straight.

FIELD OF THE INVENTION

This invention generally relates to a surgical tool arrangement useful for performing endoscopic surgical procedures which includes a powered handpiece and, more particularly, to a cutting accessory which detachably connects to the handpiece and incorporates multiple blade configurations which allow the user to perform multiple cutting styles with one accessory.

BACKGROUND OF THE INVENTION

Endoscopic surgical procedures are routinely performed in order to accomplish various surgical tasks. In such a surgical procedure, small incisions or portals are made in the patient. An endoscope, which is a device that allows medical personnel to view the surgical site, is inserted in one of the portals. Surgical instruments used to perform other tasks are inserted into other portals. The surgeon views the surgical site through the endoscope to determine how to manipulate the surgical instruments in order to accomplish the desired procedure. An advantage of performing endoscopic surgery is that, since the portions of the body that are cut open are minimized, the portions of the body that need to heal after the surgery are likewise reduced. Moreover, during an endoscopic surgical procedure, only relatively small portions of the patient's internal organs and tissue are exposed to the open environment. This minimal opening of the patient's body lessens the extent to which a patient's organs and tissue are open to infection.

The ability to perform endoscopic surgery is enhanced by the development of powered surgical tools especially designed to perform such procedures. Once such tool is sold by the Assignee hereof under the trademark FORMULA®. This tool is in the form of a cylindrical handpiece designed to be held in the hand of the surgeon. The handpiece has a front or distal end provided with a coupling assembly for releasably holding a cutting accessory, and a motor disposed within a handpiece housing which drives the accessory. One such cutting accessory, often termed a “shaver”, includes a hub which defines the proximal end of the accessory and is appropriately configured to cooperate with the coupling assembly of the handpiece to lock the accessory thereto, an elongated and tubular housing element having a proximal end fixed to the hub, and an elongated cutting element including a drive shaft disposed within the housing element. When the accessory is attached to the handpiece, the handpiece motor couples to the drive shaft of the accessory and moves same relative to the outer housing element. The handpiece motor is selectively actuable to drive the accessory drive shaft so as to cause a desired cutting action at the distal end of the accessory. The handpiece is associated with a control unit which controls the functioning thereof, and is actuated by the user via appropriate buttons provided on the handpiece itself, or alternatively directly at the control unit.

In an endoscopic surgical procedure, irrigating fluid is introduced into the surgical site. This fluid serves as a transport media for removing tissue and debris from the surgical site. In order to remove the irrigating fluid and the material contained therein, the above handpiece and the various accessories which are usable therewith together define a suction conduit. A suction pump is connected to the handpiece to provide the suction force needed for drawing the fluid and material away from the surgical site. In order to control the suction flow through the accessory and the handpiece, the handpiece is provided with a manually operated valve which is manipulated by the surgeon to control suction of material away from the surgical site.

Mechanical cutting accessories, such as the shaver discussed above, are commonly used in arthroscopic procedures, and allow for the resection of hard and soft bodily tissues, for example, those found within the knee, shoulder and other joints. In such a cutting accessory, the outer housing element defines a window or opening at the distal end, which window is defined by an edge of the wall of the outer housing element. The cutting element drive shaft at the distal end thereof also defines a window defined by an edge of the wall of the drive shaft, and when the drive shaft is disposed within the housing element, the drive shaft window is positioned adjacent the window of the housing element. As the drive shaft is moved relative to the housing element by the handpiece motor, the cutting edge of the drive shaft window and the opposed and facing cutting edge of the housing element window cause a cutting action which effectively severs tissue located within the housing element window and between the opposed cutting edges of the housing element and drive shaft. The configurations of these opposed edges allow for removal of particular tissue types, and a variety of different blade geometries are available to specifically address the type of cutting the accessory is to carry out. For example, providing the windows of both of the housing element and drive shaft with straight cutting edges is useful for making fine or detailed cuts and removing areas of hard tissue, such as bone. Alternatively, providing the distal ends of both the housing element and drive shaft with toothed or serrated cutting edges achieves a more aggressive cut and is useful for removal of soft fibrous tissue. Thus, a surgeon may often need to switch cutting accessories during a procedure in order to carry out the appropriate type or style of cut.

While the above-described surgical accessories have proven useful, when a change in cutting is desired, these accessories require the user to remove the accessory currently in use from the patient, to remove the accessory from the handpiece, install a different accessory onto the handpiece, and then reinsert the new accessory into the surgical site. Further, the known arrangements require the purchase of a multitude of accessories, which results in higher costs and a larger number of surgical accessories which must be present in the operating room in order to carry out the desired surgical procedure.

In order to obviate or at least minimize the above disadvantages of known arrangements, the surgical accessory according to the invention combines two types of cutting styles into one accessory. Specifically, in one embodiment, the two opposite sides of the cutting window of each of the outer housing element and the cutting element drive shaft have differently-configured cutting geometries, such that each window combines two different blade styles into one window. Further, the cutting geometries of the housing element window and the cutting element drive shaft window are reversed from one another, such that the accessory will perform one cutting style in one direction of rotation of the drive shaft, for example, a “straight-on-straight” cutting style wherein the opposed cutting edges of the drive shaft window and the housing element window are both straight, and such that the accessory will perform a different cutting style in an opposite direction of rotation of the drive shaft, for example, a “tooth-on-tooth” cutting style wherein the opposed cutting edges of the drive shaft window and the housing element window are both serrated or toothed. Providing this type of blade geometry on an accessory allows the surgeon to perform two different types of cutting without having to remove the accessory from the patient and then from the handpiece, thus saving time during a procedure and reducing equipment costs.

A further embodiment of the invention also combines two types of cutting styles into one accessory. In this embodiment, a surgical accessory is provided which includes a tubular housing element in which an inner cutting element is disposed for rotation relative thereto. Further, an outer sheath is provided over the housing and cutting elements, which sheath defines an opening or window at its distal end. The housing element in this embodiment is thus an intermediate component located radially between the sheath and the cutting element. The housing element defines therein a pair of windows located on opposite sides of the distal end thereof, wherein one of these windows is configured with a first cutting style, and the opposite window is configured with a second cutting style different from the first cutting style. The cutting element located within the housing element also defines a cutting window at its distal end, which window is configured with a cutting style which in one embodiment matches the cutting style of one of the housing element windows.

The outermost sheath is movable relative to the housing and cutting elements, and can be moved by the user into a first position wherein the sheath opening is circumferentially aligned with one of the cutting windows of the housing element, or a second position wherein the sheath opening is aligned with the other or opposite cutting window of the housing element. While the first embodiment discussed above allows the surgeon to select the type of cutting style by changing the direction of rotation of the cutting element drive shaft relative to the housing element, this embodiment allows the user to rotate the outer sheath relative to the housing and cutting elements to select the type of cutting style desired.

Alternatively, the two cutting edges of the cutting window of one or both of the cutting element or housing element may be provided with different geometries as in the first embodiment, and the cutting element can be actuated in different rotational directions to provide additional or alternative cutting-style options.

Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction toward the end of the arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, a surgical tool arrangement10according to the invention is illustrated. The arrangement10includes a handpiece11, which at its distal end mounts thereon a surgical accessory12.

Handpiece11is a commercially available surgical handpiece manufactured by the assignee hereof, under Model Nos. 375-704-500 and 375-701-500, and is accordingly only briefly described herein. Handpiece11includes an elongate outer housing13defining an elongate bore14therein. A motor15(shown diagrammatically only inFIG. 1) is disposed within housing bore14. Motor15includes an output or drive shaft16, which drive shaft16mounts a drive pin17at the distal end thereof. A power cable18is coupled to the proximal end of handpiece11for supplying power to motor15.

Handpiece housing13defines therein an elongate suction bore (not shown) extending generally parallel to and sidewardly of housing bore14. This suction bore communicates with a diagonally extending suction passage20defined in housing13, which passage20provides communication between the distal end of housing bore14and the suction bore. Suction is drawn through the handpiece11by a suction pump (not shown), which is connected to the handpiece11via a suction tube21. Suction flow through the handpiece11is regulated by an adjustable valve22having a valve stem (not shown) which is movably mounted in a valve bore23defined in housing13. The valve22is adjusted by the user via a movable handle or arm24connected to the valve stem. The above handpiece suction arrangement is described in detail in U.S. Patent Application Publication No. 2003/0135151A1 published on Jul. 17, 2003, which is owned by the same assignee hereof and is hereby incorporated by reference herein.

The accessory12is removably attached to the distal end of the handpiece11by a coupling assembly25provided on the handpiece11. Coupling assembly25includes a generally ring-shaped collet26secured to the distal end of the handpiece housing13. A locking ring27is movably disposed in collet26and is biased to hold the accessory12within the housing bore14of handpiece11. A release button28is provided on locking ring27, and is used to release the locking ring27and allow removal of the accessory12from handpiece11. Further, a coil30is provided in collet26, which is used to facilitate inductive signal transfer to/from a radio-frequency identification device (RFID) disposed in the accessory12as discussed below.

Referring toFIGS. 2-4, the accessory12will now be described. Accessory12includes an outer cannula or tubular housing element32and a tubular cutting element33disposed within housing element32. Housing element32includes a hub34which defines the proximal end thereof. Hub34is defined by a generally tubular base body35, which defines therein a pair of generally rectangular and diametrically-opposed openings36adjacent the proximal end thereof. Base body35also has formed thereon a pair of outwardly-projecting, diametrically opposed and generally ramp-shaped ears37disposed distally of openings36. Ears37cooperate with coupling assembly25of handpiece11to secure accessory12therein. Hub34has a distal end defined by a head39or nose of a reduced diameter as compared to base body35. In the illustrated embodiment, a thread40extends about the circumference of head39, which thread40may be used to attach an operating cannula (not shown) over housing element32. Further, hub34defines therein a bore41which extends completely through the hub34, and with which openings36of base body35communicate.

An annular seal45is disposed within the proximal end of bore41of hub34. Seal45is constructed of a resilient elastomeric material, and is defined by a main section46and axially-spaced proximal and distal sections47and48disposed at respective opposite ends of the main section46. Proximal section47defines thereon a pair of annular ribs55and56, which are disposed in sealing engagement with an inner annular surface of collet26of handpiece11when accessory12is coupled thereto, as shown inFIG. 2. Distal section48defines thereon a pair of outwardly projecting and diametrically-opposed lock tabs57which engage within the respective openings36of hub34to secure the seal45to hub34and fix the axial position of seal45relative thereto. Distal section48additionally defines thereon a pair of inwardly projecting and diametrically-opposed stop tabs58, which are generally radially aligned with the respective lock tabs57. As shown inFIGS. 2 and 4, an RFID device59encapsulated within a ring structure is located within hub bore41distally from, and in axially-adjacent relationship with, the distal section48of seal45.

The above-described coupling arrangement of handpiece11and the arrangement of the encapsulated RFID device59and coil30are disclosed in U.S. Patent Publication No. 2004/0220602A1 published on Nov. 4, 2004, which publication is owned by the same assignee hereof and is hereby incorporated by reference herein.

Housing element32additionally includes an elongate housing tube64which projects distally from hub34. More specifically, housing tube64has a proximal end which is fixedly mounted within the distal portion of bore41of hub34. Housing tube64defines an elongate bore or conduit65therein, in which the cutting element33is disposed as discussed below. As best shown inFIGS. 6 and 7, housing tube64has a distal end66which is cut so as to define a window67, which window67in the illustrated embodiment opens generally sidewardly of the tube64, such that the distal end66is generally closed in the axial direction. The cutting of the housing tube64results in a ring-shaped edge of housing tube64which defines cutting window67, which edge has circumferentially-spaced and opposed and generally longitudinally-extending sides70and71. In the illustrated embodiment, one of these sides70is serrated so as to define a plurality of teeth thereon, and the other side71is non-toothed. In the illustrated embodiment, side71of window67, as same extends longitudinally, has a generally straight or linear central region and curved end regions on opposite axial sides of the central region. However, it will be appreciated that side71may have a linear or straight configuration along its entire longitudinal extent.

Turning now to cutting element33, same includes a hub80which defines the proximal end thereof. Hub80incorporates a motor-engaging drive element81defining a proximally opening bore82therein in which a coil spring83is located, and a slot84which extends transversely to the longitudinal axis of the cutting element33. Hub80additionally includes a neck85which projects distally from drive element81. Neck85terminates at a head86which has an enlarged outer diameter as compared to the remainder of neck85. In this regard, the outer diameter of head86is slightly larger than the inward projection of the respective stop tabs58of seal45. A bore87extends through neck85and head86, in which an elongate and tubular drive shaft88is fixed. Drive shaft88defines therein a suction passage89which is in communication with a suction port90defined in neck85, which suction port90is in turn in communication with suction passage20of handpiece11.

Drive shaft88has a distal end91which is cut so as to define a window or opening93. Window93in the illustrated embodiment opens generally sidewardly of the drive shaft88, such that distal end91is generally closed in the axial direction. The cutting of drive shaft88results in a ring-shaped edge which defines cutting window93. This ring-shaped edge of drive shaft88has circumferentially-spaced and opposed and generally longitudinally-extending sides94and95. As best shown inFIGS. 5 and 6, side94of cutting window93in the illustrated embodiment is serrated or toothed, and the opposite side95of window93is non-toothed and generally straight.

The cutting element33is assembled to the outer tubular housing element32by inserting the distal end91of drive shaft88of cutting element33into bore41at the proximal end of hub34. During this insertion, the enlarged head86of hub80expands the seal45and head86pushes past the stop tabs58, at which point the seal45essentially resumes its original shape. The stop tabs58, while allowing some axial displacement of cutting element33relative to housing element32, prevent the cutting element33from detaching or falling out of the housing element32due to gravitational forces.

The assembled accessory12is secured to the handpiece11in a similar manner to that described in the '602 publication referenced above, and will accordingly be only briefly described here. Accessory12is attached to handpiece11by inserting the hubs34and80into the open distal end of collet26. The ears37of hub34seat within collet26, and the locking ring27serves to hold the accessory12within handpiece11. The above securement of the accessory12to handpiece11causes the drive element81to engage the motor output shaft16. More specifically, the drive pin17of output shaft16seats within slot84of drive element81, such that the rotational movement of output shaft16is transferred to the cutting element33. The spring83of drive element81biases the cutting element33forwardly or in the distal direction, so as to maintain the distal end91of cutting element33in bearing contact with the interior of the closed distal end66outer housing element32.

In operation, the distal end of tool10is inserted into the surgical site. If desirable or necessary, the distal end of tool10can be inserted into the surgical site through a working portal defined by a conventional cannula or trocar (not shown). The cutting element33is controlled by a control unit (not shown) connected to handpiece cable18, which control unit supplies electrical power to the motor15of handpiece11in order to actuate cutting element33. Control unit also controls the mode of operation of cutting element33, for example by controlling motor15so as to drive cutting element33in a forward or reverse direction, or in an oscillating manner. If cutting of tissue is desired, then motor15is activated so as to cause cutting element33to rotate within and relative to outer housing element32. In this regard, it will be appreciated that the control unit may include appropriate control buttons so as to allow the surgeon or operator to select the desired accessory operations. These control functions of the cutting element33may alternatively be performed directly from the handpiece11which would then include the appropriate control buttons thereon. Alternatively, the control unit may be associated with a switch, either through a suitable cable or wirelessly, to allow the surgeon to operate the controls remotely. Such a switch may be a footswitch or a hand switch.

As shown inFIG. 6, with the cutting element33disposed within housing element32and the accessory12secured to handpiece11as described above, the toothed sides94and70of the respective cutting element window93and the housing tube window67are positioned on opposite longitudinal sides of the distal end of accessory12, and the non-toothed sides95and71are positioned on opposite longitudinal sides of the distal end of accessory12. This configuration allows the accessory12to perform one type of cutting or cutting style in the forward mode, and in the reverse mode the accessory12will perform a different type of cutting or cutting style. Further, in the oscillation mode, wherein the cutting element33oscillates rotationally relative to the outer housing element32about the longitudinal axis of the accessory12, the accessory12will perform in both cutting styles. More specifically, when motor15is activated in a forward mode to cause cutting element33to rotate within and relative to outer housing element32(see arrow F inFIG. 6), the toothed side94of cutting element33is rotated towards and then past the toothed side70of outer housing element32, which effectively cuts tissue located adjacent or within cutting window67. This “tooth-on-tooth” mode can be utilized when a more aggressive tissue resection is desirable or necessary. When motor15is activated in a reverse mode (see arrow R inFIG. 6), the non-toothed side95of cutting element33is rotated towards and then past the non-toothed side71of outer housing element32to cut tissue located within/adjacent window67. This “straight-on-straight” mode can be utilized when fine or detailed cutting is desirable or necessary.

If desirable or necessary, suction can be provided at the surgical site by manipulating valve22on handpiece11to draw surgical debris from the surgical site through windows67and93, into drive shaft suction passage89, into handpiece suction passage20and proximally through the handpiece11towards the suction pump.

The accessory12according to the invention thus allows the combination of two different blade styles into one tool or accessory, which is advantageous in that the surgeon need not remove the accessory12from the surgical site in order to change to a different cutting style, and can also reduce the costs associated with purchasing multiple blades. It will be appreciated that the accessory12can be customized for a particular surgical procedure, by providing two different blade styles which are particularly suited to a given surgical procedure. Thus, the “tooth-on-tooth” and “straight-on-straight” cutting styles of the outer housing element32and cutting element33are provided only as an example of one type of configuration of accessory12, and other blade styles can be provided according to the invention.

Further, it will be appreciated that only one of the cutting windows67or93of the housing element32and the cutting element33may be provided with a window having differently-configured cutting edges, and the other element may be provided with a window having cutting edges of the same configuration. This arrangement will still allow two different cutting styles to be carried out upon rotation of the cutting element33in different directions relative to housing element32. For example, the cutting window of cutting element33can be provided with both toothed and straight cutting edges and the window of the housing element32can be provided with two straight cutting edges. This arrangement will provide a “tooth-on-straight” cutting action in one direction of rotation of element32, and a “straight-on-straight” cutting action in the opposite direction of rotation.

FIGS. 7-11illustrate a further embodiment of the invention which will now be described. Components of this embodiment which are similar to or identical to components of the prior embodiment will include the same reference numbers as in the prior embodiment plus “100”, and a detailed description of all components will accordingly not be provided. The surgical accessory100shown inFIGS. 7-11generally includes an outermost sheath101, a tubular housing element132and a tubular cutting element133. Tubular cutting element133is disposed within housing element132, and housing and cutting elements132and133are disposed within sheath101, such that housing element132is located radially between sheath101and cutting element133and thus is an intermediate component.

Housing element132is fixed at its proximal end to a hub134which is substantially identical to hub34of the prior embodiment, and thus hub134will not be discussed in detail here except where same differs from hub34. Housing element132includes a housing tube164defining an elongate bore or conduit165therein in which cutting element133is disposed. Housing tube164has a distal end166which is cut on opposite sides so as to define a pair of windows173and174which open into conduit165. Windows173and174, in the illustrated embodiment, are disposed approximately 180 degrees from one another along the outer circumference of housing tube164. Windows173and174each open generally sidewardly of the housing tube164, such that distal end166thereof is generally closed in the axial direction. Each of the cutting windows173and174is generally ring-shaped. Cutting window173has a pair of circumferentially-spaced, opposed and generally longitudinally-extending sides, both of which sides in the illustrated embodiment are serrated or toothed. The opposite cutting window174has a pair of circumferentially-spaced, opposed and generally longitudinally-extending sides, each of which sides in the illustrated embodiment is non-toothed or generally straight.

Cutting element133is fixed at its proximal end to a hub180which is identical to hub80of accessory12described above. Cutting element133includes a tubular drive shaft188, the proximal end of which is mounted within the bore of hub180. Drive shaft188defines therein a suction passage189in communication with suction port190of hub180and suction passage20of handpiece11. Cutting element133has a distal end191which defines a window or opening193therein. Window193opens generally sidewardly of drive shaft188such that distal end191is closed in the axial direction. Cutting window193is generally ring-shaped and has a pair of opposed and generally longitudinally-extending sides, both of which sides in the illustrated embodiment are serrated or toothed.

Turning now to outermost sheath101, same is defined by a tubular wall200having a distal end201. Distal end201is cut so as to define a window202therein which opens generally sidewardly of wall200such that distal end201is closed in the axial direction. Further, tubular wall200of sheath101defines an elongate conduit204therein in which housing and cutting elements132and133are disposed, and thus the inner diameter of conduit204is of a dimension slightly larger than an outer diameter of housing tube164of housing element132.

As shown inFIG. 7, sheath101has a proximal end206on which an adjustment knob208is fixed. In one embodiment, knob208is annular in shape and opens proximally so as to fit over nose139of hub134of housing element132, and opens distally so as to mount therein the proximal end206of sheath101. In this regard, knob208is fixed to sheath101, but is rotatably movable relative to hub134between a first position in which sheath window202is circumferentially and axially aligned with window173of housing element132, and a second position in which sheath window202is circumferentially and axially aligned with the opposite window174of housing element132. These positions, located approximately 180 degrees from one another, may be achieved by providing stops in appropriate positions on nose139of hub134. Knob208may be provided with one or more adjustment levers209which project outwardly from knob208and aid the user in moving the knob208into the desired rotational position.

The cutting element133is assembled to housing element132in the same manner as discussed above relative to accessory12, and thus such assembly will not be repeated here. The distal end166of housing element132is inserted into the proximal end of adjustment knob208and into sheath101, and sheath101is moved rearwardly relative to housing element132until knob208seats over and onto nose139of hub134. Sheath101is retained on hub134in the axial direction via friction or other suitable retaining structures. The assembled accessory100is secured to the handpiece11in the same manner that accessory12is secured to handpiece11.

In operation, the sheath101is adjusted to the correct rotational position relative to outer housing element132using knob208so as to expose appropriate window173or174of housing element132depending upon what type of cutting action is desirable or necessary. The distal end of accessory12is inserted into the surgical site, and the handpiece motor15activated so as to drive cutting element133in a forward, reverse or oscillating mode.FIG. 9illustrates the distal end of the accessory100when the sheath101is positioned so that the toothed cutting window173of housing element132is exposed, which when the cutting element133is rotated by motor15in the forward, reverse or oscillating mode will provide a “tooth-on-tooth” cutting action, for example, to achieve an aggressive cutting action. With the sheath101in this position, one toothed side of the cutting window193of cutting element133will rotate towards and past the opposed toothed side of cutting window173of housing element132, which cuts tissue located adjacent/within cutting window173.FIG. 10illustrates the distal end of the accessory100when the sheath101is positioned so that the non-toothed cutting window174is exposed, which when the cutting element133is rotated in the forward, reverse or oscillating mode will provide a “tooth-on-straight” cutting action, for example to make a less aggressive cut than a “tooth-on-tooth” cutting action.

The accessory100, as in the first embodiment, thus allows the combination of two different blade styles into one tool or accessory, which avoids the surgeon having to remove the accessory100from the surgical site and from the handpiece11to switch cutting styles. Accessory100can also help to reduce costs in that not as many blades need be purchased. It will be appreciated that the accessory100can be customized for particular surgical procedures, and that the blade configurations provided at the cutting windows may vary from what is depicted herein.

FIG. 11illustrates an alternative embodiment of the cutting element133described above, which cutting element333can be provided in place of cutting element133. Specifically, cutting element333in this embodiment includes a tubular drive shaft388having a distal end391. Distal end391defines a window or opening393therein which opens generally sidewardly of drive shaft388such that distal end391is closed in the axial direction. Cutting window393is generally ring-shaped and has a pair of opposed and generally longitudinally-extending sides, one of which sides394is serrated or toothed, and the other of which sides395is generally straight.

In this embodiment, when sheath101is positioned so as to expose toothed cutting window173of housing element132, cutting element333when rotated by motor15in the forward direction (shown by arrow “F” inFIG. 11) will provide an aggressive “tooth-on-tooth” cutting action via the cooperation of toothed cutting edge394of cutting element333and toothed window173of housing element132, and when rotated by motor15in the reverse direction (shown by arrow “R” inFIG. 11) will provide a less aggressive “straight-on-tooth” cutting action via the cooperation of straight cutting edge395and toothed window173. When sheath101is positioned so as to expose straight cutting window174of housing element132, cutting element333when rotated in the forward direction F will provide a “straight-on-tooth” cutting action via cooperation of toothed cutting edge394and window174, and when rotated in the reverse direction R will provide a “straight-on-straight” cutting action via cooperation of straight cutting edge395and window174and from the handpiece for a more precise cut.

Thus, the above embodiment which utilizes a cutting window393which incorporates two different cutting styles in a single cutting window, provides the surgeon with two different cutting styles in each rotational position of the sheath101. This embodiment also avoids the surgeon having to remove the accessory from the surgical site and then from the handpiece11in order to change to a different cutting style, and can also reduce the number of accessories which must be purchased and which must be present during a surgical procedure.

It will be appreciated that the housing element132may be configured with a cutting window or windows similar to that shown above relative to cutting element333(in addition to or in place of cutting element333) which may provide additional or alternative cutting styles than those discussed above.