Patent Description:
It is known that medical practitioners have found it useful to use surgical instruments to assist in the performance of surgical procedures. The practitioner is able to position the surgical instrument at a site on a patient at which the surgical instrument is to perform a medical or surgical procedure. Many surgical instruments have been developed for use in surgical procedures, in particular, endoscopic procedures, to reduce incision size and improve access and visibility, thereby enhancing surgical outcomes with quicker recovery. Some surgical instruments include a cutting assembly removably coupled to a drive assembly. Typical cutting assemblies may include two tubes, one within another, or a single tube defining a cutting window. Alternatively, some cutting assemblies include a single tube within which and a shaft having a bur is rotatably disposed. Such cutting devices may be an ear, nose, and throat (ENT) shaver or bur device.

Removably coupling the cutting assembly to the drive assembly of the surgical instrument typically occurs immediately prior to the performance of the surgical procedure. With cutting assemblies that include two tubes, the inner tube is rotatable within an outer tube. The inner and outer tubes may be arranged such that an irrigating fluid may be directed in a space defined between the inner and outer tubes. Consequently, the inner and outer tubes in typical cutting assemblies may not be rigidly coupled to one another, and the inner tube may undesirably move or shift during handling of the cutting assembly, particularly after removal from packaging and prior to coupling the cutting assembly with the drive assembly.

Moreover, the drive assemblies known in the art often include suction and irrigation ports. These suction and irrigation ports are configured to be coupled to suction and irrigation tubes, respectively. However, the placement of the suction and irrigation ports in typical drive assemblies often result in the suction and irrigation tubes interfering with one another during the performance of the surgical procedure. Furthermore, the placement of the suction and irrigation ports in typical drive assemblies may not provide adequate clearance for the practitioner's hand for ease with coupling the suction and irrigation tubes to the suction and irrigation ports, respectively.

A surgical tool arrangement including a handpiece which is capable of accepting and operating a number of different surgical tools or instruments adapted for use with the handpiece, each having one or multiple functions, is known from <CIT>. The handpiece incorporates a coupling arrangement located at a distal end thereof which serves to attach the desired surgical instrument to the handpiece via a locking mechanism, and also provides an electrical contact arrangement to support the functioning of an electrosurgical probe as well as a combined mechanical cutting and electrosurgical tool. Additionally, the handpiece accepts a conventional cutter which only requires power for driving a movable cutting element.

According to <CIT>, a method for treating a body tissue comprises delivering a cutting mechanism of a surgical instrument into proximity to a target portion of the body tissue, wherein the cutting mechanism includes a first member defining a lumen and a distal cutting tip. At least the first member is supported, via a coupler, by the handpiece. A fluid pathway extends from the distal cutting tip, through the lumen of the first member, and through an interior of the handpiece for fluid connection to a source of negative pressure. In one configuration, a coupler provides an internally-located aspiration control mechanism including a user interface port exteriorly exposed on the coupler and defining an aspiration control pathway extending from the user interface port to a proximal window of the inner member for communication with the lumen of the inner member. With the distal cutting tip placed into contact with the target portion, the treatment site is selectively aspirated by manipulating a position of a finger relative to the user interface port to manually effectuate an altering of a level of vacuum applied by the source of negative pressure at the distal cutting tip.

As such, there remains a need to provide for an improved surgical instrument that overcomes one or more of the aforementioned disadvantages.

A cutting assembly for a surgical instrument including a drive assembly, and a handpiece defining a handpiece irrigation path and a suction flow path is defined in claim <NUM>. Optional features are defined in the dependent claims.

An exemplary embodiment of the present disclosure is directed to a cutting assembly and a drive assembly for a surgical instrument. Said exemplary cutting assembly is configured to be removably coupled to the drive assembly. The exemplary cutting assembly includes an outer tube extending along an axis, and a cutting implement. The exemplary cutting implement includes a distal cutting end and a cutting shaft coupled to the distal cutting end. The cutting shaft extends along the axis and is coaxially disposed within and rotatable relative to the outer tube. The exemplary cutting assembly also includes a drive hub defining a bore. The exemplary cutting assembly further includes a seal disposed about the drive hub. The cutting shaft may be an inner tube defining a lumen and rotatably disposed within the outer tube such that the distal cutting end is a cutting window. The lumen may be in fluid communication with the cutting window. Optionally, the cutting shaft is solid, and the distal cutting end is a bur. The cutting shaft may even be the inner tube defining the lumen, and the distal cutting end may be a bur. The outer tube may define a distal tube opening through which the cutting shaft and/or bur extends.

The cutting assembly of said exemplary embodiment includes an outer hub. The outer hub may include a proximal portion defining a cavity. The outer hub further defines an irrigation aperture in fluid communication with the cavity defined by the proximal portion of the outer hub. The cutting shaft of the cutting implement extends through the irrigation aperture into the cavity. The outer tube is rigidly coupled to the outer hub. The cutting shaft extends along the axis through the outer tube and the outer hub such that a proximal end of the cutting shaft is disposed within the cavity. The proximal end of the cutting shaft may be disposed within the bore and may be rigidly coupled to the drive hub. The seal may be coupled to the outer hub and may be at least partially disposed within the cavity. The cutting implement and the drive hub may be slidably moveable relative to the outer hub between a first position in which the retention flange is distal to the seal and fluid is permitted to flow through the cavity to the irrigation aperture, and a second position in which the retention flange contacts the seal. In the first position, the retention flange may be positioned between the distal end of the seal and the proximal portion of the outer hub. The retention flange may be positioned at, or optionally adjacent to, the distal end of the seal. The retention flange may be positioned at, or optionally adjacent to, the distal end of the seal when the drive hub is moved from the first position toward the second position.

In certain implementations of said exemplary embodiment, the outer hub may be disposed at least partially about the outer tube, the cutting shaft, and the drive hub. The outer hub may be engageable by a latching mechanism to removably couple the cutting assembly to the drive assembly. The proximal portion may have an expanded diameter portion which at least partially defines the cavity. The expanded diameter portion of the proximal portion of the outer hub has a greater internal diameter as compared to other sections of the proximal portion of the outer hub. The expanded diameter portion may be at a proximal end of the proximal portion. The expanded diameter portion may be shaped as to form a step or a series of steps into the outer hub. Optionally, the expanded diameter portion may be spaced from the proximal end of the proximal portion. The expanded diameter portion may be shaped as to define a groove into the outer hub. The seal may include a locking tab engageable with the expanded diameter portion of the proximal portion of the outer hub. The locking tab of the seal may extend radially away from the axis relative to a body of the seal.

In certain implementations of said exemplary embodiment, the drive hub includes a retention flange extending radially away from the axis. The retention flange may be spaced from the seal such that the retention flange is disposed axially between the seal and the outer tube. The drive hub and the exemplary cutting implement may be movably slidable relative to the outer hub when the exemplary cutting assembly is not detachably coupled with the drive assembly of the surgical instrument. The drive assembly may have a handpiece defining a handpiece irrigation path. The exemplary cutting assembly may include the outer hub including the proximal portion defining the cavity. The exemplary cutting assembly may include the outer tube extending along the axis and rigidly coupled to the outer hub. The exemplary cutting shaft may extend along the axis through the outer tube and the outer hub such that the proximal end of the exemplary cutting shaft is disposed within the cavity. The proximal end of the exemplary cutting shaft may be disposed within the bore of the drive hub and may be rigidly coupled to the drive hub. The seal may be coupled to the outer hub. The seal may be at least partially disposed within the cavity.

In certain implementations of said exemplary embodiment, the retention flange has a first radius relative to the axis. The innermost point of the seal has a second radius relative to the axis. The first radius may be greater than the second radius to prevent the drive hub from moving axially past the seal. The drive hub may have a distal end. The distal end of the drive hub may have a third radius relative to the axis. The third radius of the drive hub at the distal end of the drive hub may be less than the first radius of the retention flange. Optionally, the retention flange may be spaced apart from the distal end of the drive hub. The retention flange may be at the distal end of the drive hub such that the retention flange is the axial terminus of the drive hub. The drive hub may have a proximal end spaced from the distal end of the drive hub. The proximal end of the drive hub may have a radius approximately equal to, or optionally exactly equal to, the third radius of the distal end of the drive hub. The retention flange and the drive hub may be in physical contact with one another such that the retention flange abuts the seal in the second position.

In certain implementations of said exemplary embodiment, the retention flange includes a first retention surface facing the seal, and a second retention surface facing the retention flange. The first retention surface of the retention flange may abut the second retention surface of the seal in the second position. The first retention surface of the retention flange may be spaced apart from the second retention surface of the seal when moved from the second position toward the first position. The retention flange may extend completely circumferentially about the axis to form a general disk shape. Optionally, the retention flange may extend only partially about the axis. The retention flange may extend radially away from the axis at two or more points circumferentially spaced from one another about the axis. Optionally, the retention flange may form a generally polygonal shape, such as, but not limited to, triangular, rectangular, pentagonal, hexagonal, heptagonal, or octagonal.

In certain implementations of said exemplary embodiment, the seal may be annular in shape between proximal and distal ends of the seal to define an irrigation channel. The retention flange may be positioned between the distal end of the seal and the proximal portion of the outer hub when the drive hub, and thus the cutting assembly, is removably coupled with the drive assembly of the surgical instrument so as to provide the irrigation channel between the seal and the drive hub. The outer hub may also define seating holes into which the seal may at least partially extend. The seal may deform to at least partially be seated within the seating holes defined by the outer hub. The seal may have a lip that extends at least partially into the seating holes to prevent rotation of the seal relative to the outer hub. The seal may have an innermost point relative to the drive hub. The retention flange may be disposed axially between the innermost point of the seal and the outer tube.

In certain implementations of said exemplary embodiment, the innermost point of the seal may be radially aligned with the locking tab of the seal. The innermost point of the seal may be radially spaced from the locking tab of the seal such that the innermost point of the seal is disposed radially between the locking tab of the seal and the axis. The innermost point of the seal may be radially aligned with the expanded diameter portion of the outer hub. The retention flange may be capable of being unobstructed by the seal radially between the drive hub and the outer hub. The retention flange may be moveable between a first flange position and a second flange position. In the first flange position, the retention flange is unobstructed by the seal radially between the retention flange and the outer hub. In the second flange position, the retention flange is obstructed by the seal radially between the retention flange and the outer hub such that the seal is disposed between the retention flange and the outer hub.

The exemplary cutting assembly may further include an irrigation spacer disposed distal to the drive hub. The irrigation spacer may include an inner irrigation spacer surface facing the axis. The inner irrigation spacer surface may extend at least partially circumferentially about the axis at a first radial distance. The inner irrigation spacer surface may define a bore through which the outer tube is disposed. Moreover, the irrigation spacer may include an outer irrigation spacer surface facing away from the axis. The outer irrigation spacer surface may extend at least partially circumferentially about the axis at a second radial distance. It is to be appreciated that the second radial distance may be greater than the first radial distance. The outer irrigation spacer surface may be spaced from the inner irrigation spacer surface such that the inner irrigation spacer surface is disposed radially between the axis and the outer irrigation spacer surface. The irrigation spacer may define an irrigation passageway between the first and second radial distances. The irrigation spacer may comprise plastic, including injection-molded plastic. Optionally, the irrigation spacer may comprise a variety of materials, including, but not limited to, metals including stainless steel, ceramics, and composite materials.

In certain implementations of said exemplary embodiment, the irrigation spacer may have fins extending radially away from the axis. The fins may be spaced circumferentially about the axis. The fins may define the irrigation passageway. The irrigation spacer may have two, three, four, five, six, seven, eight, or more than eight fins. The outer irrigation spacer surface may be interrupted and thus does not extend completely circumferentially about the axis. Optionally, the irrigation passageway may be defined by the irrigation spacer without any fins. The irrigation spacer may be completely solid but for the bore defined by the inner irrigation spacer surface and but for the irrigation passageway defined between the inner and outer irrigation spacer surfaces. The outer irrigation spacer surface may extend completely circumferentially about the axis at the second radial distance without interruption. The outer hub may have a key that extends at least partially into the irrigation passageway to limit rotation of the irrigation spacer relative to the outer hub. The irrigation spacer may be engageable with the drive hub. The exemplary cutting assembly may further include at least one washer disposed between the irrigation spacer and the drive hub to assist the irrigation spacer in engaging the drive hub. The at least one washer may be one washer, two washers, three washers, or more than three washers.

In certain implementations of said exemplary embodiment, the outer hub may be disposed in the cavity defined by the proximal portion of the outer hub. The outer hub may have an inner hub surface that tapers distally toward the axis. The inner hub surface may have a smaller diameter at the distal end of the inner hub surface and may have a larger diameter at the proximal end of the inner hub surface. The outer irrigation spacer surface of the irrigation spacer may taper distally toward the axis. Said differently, the outer irrigation spacer surface may have a smaller diameter at the distal end of the outer irrigation spacer surface and may have a larger diameter at the proximal end of the outer irrigation spacer surface. The inner hub surface and the outer irrigation spacer surface may be engageable with one another to maintain a relative axial position between the outer hub and the irrigation spacer. Optionally, the inner hub surface and the outer irrigation spacer surface may be press-fit with one another. Optionally, the tapered profiles of the inner hub surface and the outer irrigation spacer surface may only loosely fit together.

According to said exemplary embodiment, the drive assembly for the surgical instrument includes the handpiece extending along the axis. The handpiece may include a distal end defining a distal opening inwardly from the distal end that is dimensioned to receive the outer hub of the cutting assembly. The handpiece may also include a proximal end defining a proximal opening inwardly from the proximal end. A back cap may be coupled to the handpiece so as to be at least partially disposed within the proximal opening. A motor may be disposed within the handpiece. The motor may have an output shaft rotatable about the axis. A coupling member may be attached to the output shaft. Optionally, the handpiece may include the latching mechanism coupled to the distal end of the handle body. The latching mechanism may include a button aligned radially with the upper aspect of the handpiece in the operative orientation.

In certain implementations of said exemplary embodiment, the drive assembly may also include an irrigation port coupled to the handpiece. The drive assembly may further include a suction port coupled to the back cap. A proximal end of the irrigation port may be positioned distal to a position where the suction port is coupled to the back cap. The irrigation port may include a distal end coupled to the handpiece and the proximal end opposite the distal end. The suction port may include a distal portion disposed within and coupled to the handpiece. Optionally, the distal portion of the suction port may be disposed within and coupled to the back cap of the handpiece. The suction port may also include a proximal portion extending proximally from the handpiece. The proximal portion of the suction port may extend proximally from the back cap of the handpiece. The proximal end of the irrigation port may be positioned axially distal to the proximal portion of the suction port. The proximal end of the irrigation port may be axially distal to the proximal portion of the suction port. The proximal portion of the irrigation port may begin where the irrigation port extends from the back cap. The proximal portion of the suction port may be axially distal to where the irrigation port extends from the back cap. The irrigation port and the suction port may have a barb configuration.

In certain implementations of said exemplary embodiment, the drive assembly may further include an electrical connector coupled to the handpiece. The electrical connector may be disposed in, or optionally directly attached to, the back cap of the handpiece. The electrical connector may be screwed into the back cap of the handpiece to secure the electrical connector to the drive assembly. Optionally, the electrical connector may be press-fit to, welded to, or otherwise mechanically affixed to the back cap of the handpiece. Optionally, the motor of the surgical instrument may be powered by a battery disposed within the surgical instrument. A proximal end of the electrical connector may be spaced from the proximal end of the suction port such that the suction port is disposed axially between the electrical connector and the irrigation port. In order from a proximal end of the surgical instrument to a distal end of the surgical instrument, the irrigation port, the suction port, and the electrical connector may be spaced from one another along the axis, respectively. The back cap may at least partially define an electrical channel through which electrical power may travel to power the motor. Optionally, the back cap may completely define the electrical channel. Optionally, the handpiece may at least partially define the electrical channel through which the electrical power may travel to power the motor.

In certain implementations of said exemplary embodiment, the back cap may have a suction portion adjacent to the suction port and an electrical portion adjacent to the electrical connector. The suction portion may be spaced from the proximal end of the irrigation port such that the suction portion is disposed axially between the electrical portion and the proximal end of the irrigation port. The irrigation port, therefore, may be axially distal relative to the back cap. The suction port may be generally aligned with the axis and disposed at a general radial center relative to the handpiece. The suction port, the suction flow path, the drive hub, and the lumen of the inner tube may lie in a general line parallel to the axis through the general radial center relative to the handpiece.

In certain implementations of said exemplary embodiment, the handle body may also include a saddle region near the proximal end of the handpiece. The saddle region may define a first recess and may define a lower aspect of the handpiece in an operative orientation. The lower aspect may further include a curved surface between the saddle region and the distal end of the handle body. The handle body may define a second recess near the distal end of the handle body and extending annularly about the longitudinal axis. The handle body may further include an apex region extending longitudinally between the second recess and the proximal end. The apex region may extend on either side of the surgical instrument. The apex region may include opposing surfaces that are relatively flatter than the curved surface of the lower aspect. The opposing surfaces are on either side of the surgical instrument. The opposing surfaces may be angling towards and meeting one another to define an upper aspect of the handpiece in the operative orientation. Optionally, the handle body may further define a third recess extending longitudinally along at least a portion of the opposing surfaces. The apex region may define the handpiece irrigation path internal to the handle body. The handpiece may further include the irrigation port coupled to the apex region and in fluid communication with the handpiece irrigation path. The apex region may be pyramidal in axial section or may be of a variety of shapes in axial section including, but not limited to, oval and rectangular.

Other advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:.

With reference to the Figures, wherein like numerals indicate like parts throughout the several views, a surgical instrument <NUM> is shown in perspective views in <FIG> and <FIG>. The surgical instrument <NUM> includes a cutting assembly <NUM> and a drive assembly <NUM>. The surgical instrument <NUM> may be for use in a medical procedure for a patient (not shown). In one implementation, the cutting assembly <NUM> is a shaver that is disposable and used for resecting tissue during endoscopic sinus surgery. The drive assembly <NUM> is used to rotate a portion of the cutting assembly <NUM> to remove tissue, bone, etc. from a surgical site of the patient.

The cutting assembly <NUM> includes an outer tube <NUM> extending along an axis A, and a cutting implement <NUM>. The cutting implement <NUM> includes a distal cutting end <NUM> and a cutting shaft <NUM> coupled to the distal cutting end <NUM>, extending along the axis A, and coaxially disposed within and rotatable relative to the outer tube <NUM> with the drive assembly <NUM>. The cutting assembly <NUM> also includes a drive hub <NUM> defining a bore <NUM> adapted to slidably receive a proximal end <NUM> of the cutting shaft <NUM>. The cutting assembly <NUM> further includes a seal <NUM> coupled to an outer hub <NUM>. At least a portion of the seal <NUM> may be disposed about the drive hub <NUM>.

The drive hub <NUM> includes a retention flange <NUM>. Although not required, the drive hub <NUM> and the retention flange <NUM> may be integral, unitary, and formed as one-piece. The retention flange <NUM> may extend radially away from the axis A, spaced from the seal <NUM> such that the retention flange <NUM> is disposed axially between the seal <NUM> and the outer tube <NUM>, and configured to prevent the drive hub <NUM> from moving axially past the seal <NUM> to retain the cutting shaft <NUM> within the outer tube <NUM>. By preventing the drive hub <NUM> from moving axially past the seal <NUM> to retain the cutting shaft <NUM> within the outer tube <NUM>, the retention flange <NUM> maintains the drive hub <NUM> as ready for engagement with the drive assembly <NUM>. In particular, the arrangement limits the proximal movement of the drive hub <NUM> during handling of the cutting assembly <NUM> after removal from packaging in the sterile field and prior to coupling the drive hub <NUM> with the drive assembly <NUM>. If, by contrast, the drive hub <NUM> were not maintained as ready for engagement, the cutting implement <NUM> may be ejected with improper handling, which would render the cutting assembly <NUM> either inoperable for use or unsterile for use. The improved seal <NUM> of the present disclosure advantageously addresses this shortcoming by permitting the user to handle the cutting assembly <NUM> without concern for such an occurrence while providing an improved irrigation path through the cutting assembly <NUM>.

In one implementation, the cutting assembly <NUM> includes the outer hub <NUM> comprising a proximal portion <NUM> defining a cavity <NUM>. The outer tube <NUM> extends from the outer hub <NUM>, and the outer tube <NUM> may be rigidly coupled to the outer hub <NUM>. The cutting shaft <NUM> may extend along the axis A through the outer tube <NUM> and the outer hub <NUM> such that a proximal end <NUM> of the cutting shaft <NUM> is disposed within the cavity <NUM>. Additionally, the proximal end <NUM> of the cutting shaft <NUM> may be disposed within the bore <NUM> of the drive hub <NUM> and may be rigidly coupled to the drive hub <NUM>. The seal <NUM> may be coupled to the outer hub <NUM> and may be at least partially disposed within the cavity <NUM>. The cutting implement <NUM> and the drive hub <NUM> may be slidably moveable relative to the outer hub <NUM> between a first position in which the retention flange <NUM> is between the seal <NUM> and the proximal portion <NUM> of the outer hub <NUM> (see <FIG> and <FIG>), and a second position in which the retention flange <NUM> contacts the seal <NUM> (see <FIG> and <FIG>).

The drive hub <NUM> and the cutting implement <NUM> are movably slidable relative to the outer hub <NUM> when the cutting assembly <NUM> is not detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. Further, the drive hub <NUM> and the cutting implement <NUM> may be freely removable from the outer hub <NUM> and the outer tube <NUM>, respectively, when the cutting assembly <NUM> is not detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. The second position of the drive hub <NUM> and the cutting implement <NUM> limits the extent to the drive hub <NUM> may slidably move proximally within the outer hub <NUM>. More specifically, because the retention flange <NUM> contacts the seal <NUM> in the second position, the contact between the retention flange <NUM> and the seal <NUM> prevents the drive hub <NUM> from moving axially past the seal <NUM>.

An irrigation flow path <NUM> is defined between the outer tube <NUM> and the cutting shaft <NUM>. The retention flange <NUM> of the drive hub <NUM> is configured to be spaced apart from the distal end <NUM> of the seal <NUM>, and the drive hub <NUM> is configured to be removably coupled to the drive assembly <NUM> of the surgical instrument <NUM> to permit fluid to flow from the handpiece irrigation path <NUM> to the irrigation flow path <NUM>. In other words, the spacing of the retention flange <NUM> relative to the seal <NUM> permits irrigating fluid to flow from the handpiece irrigation path <NUM>, past the seal <NUM> and the drive hub <NUM>, to the irrigation flow path <NUM> without interruption to adequately provide irrigating fluid to the surgical site of the patient.

The drive assembly <NUM> may have a handpiece <NUM> defining a handpiece irrigation path <NUM>. In such an arrangement, the cutting assembly <NUM> includes the outer hub <NUM> including the proximal portion <NUM> defining the cavity <NUM>, and includes the outer tube <NUM> extending along the axis A and rigidly coupled to the outer hub <NUM>. The cutting shaft <NUM> may extend along the axis A through the outer tube <NUM> and the outer hub <NUM> such that the proximal end <NUM> of the cutting shaft <NUM> is disposed within the cavity <NUM>. Additionally, the proximal end <NUM> of the cutting shaft <NUM> may be disposed within the bore <NUM> of the drive hub <NUM> and may be rigidly coupled to the drive hub <NUM>. The seal <NUM> may be coupled to the outer hub <NUM> and may be at least partially disposed within the cavity <NUM>.

The seal <NUM> may be annular in shape between proximal and distal ends <NUM>, <NUM> of the seal <NUM> to define an irrigation channel <NUM> configured to be in fluid communication with the handpiece irrigation path <NUM> defined by the handpiece <NUM> of the drive assembly <NUM> of the surgical instrument <NUM>. In this implementation, the retention flange <NUM> is configured to be spaced apart from the distal end <NUM> of the seal <NUM>, and the retention flange <NUM> may be positioned between the distal end <NUM> of the seal <NUM> and the proximal portion <NUM> of the outer hub <NUM> when the cutting assembly <NUM>, is removably coupled with the drive assembly <NUM>. The arrangement provides the irrigation channel <NUM> between the seal <NUM> and the drive hub <NUM>, as represented in <FIG> and <FIG>. The irrigation channel <NUM> defined between the seal <NUM> and the drive hub <NUM> results in increased flowrates of, and better control of, the flow of irrigating fluid from the handpiece irrigation path <NUM> defined by the handpiece <NUM>, through the irrigation channel <NUM> defined between the seal <NUM> and the drive hub <NUM>, and to the surgical site on the patient.

The seal <NUM> may have an innermost point <NUM> relative to the drive hub <NUM>. The retention flange <NUM> may be disposed axially between the innermost point <NUM> of the seal <NUM> and the outer tube <NUM>. The retention flange <NUM> may be unable to move axially past the innermost point <NUM> of the seal <NUM>. As a result, the drive hub <NUM> is maintained as ready for engagement with the drive assembly <NUM>. The retention flange <NUM> has a first radius R1 relative to the axis A. The innermost point <NUM> of the seal <NUM> has a second radius R2 relative to the axis A. The first radius R1 may be greater than the second radius R2 to prevent the drive hub <NUM> from moving axially past the seal <NUM>. The drive hub <NUM> may have a distal end <NUM>. In other implementations, the distal end <NUM> of the drive hub <NUM> may have a third radius relative to the axis A. The third radius of the drive hub <NUM> at the distal end <NUM> of the drive hub <NUM> may be less than the first radius R1 of the retention flange <NUM>. Because the distal end <NUM> of the drive hub <NUM> may have the third radius that is less than the first radius R1 of the retention flange <NUM>, the retention flange <NUM> may be spaced apart from the distal end <NUM> of the drive hub <NUM>. It is to be appreciated, however, that the retention flange <NUM> may be at the distal end <NUM> of the drive hub <NUM> such that the retention flange <NUM> is the axial terminus of the drive hub <NUM>. The third radius of the distal end <NUM> of the drive hub <NUM> may be less than the second radius R2 of the innermost point <NUM> of the seal <NUM> to allow the distal end <NUM> of the drive hub <NUM> to easily move axially past the seal <NUM>. It is to be appreciated that the drive hub <NUM> may have a proximal end <NUM> spaced from the distal end <NUM> of the drive hub <NUM>. The proximal end <NUM> of the drive hub <NUM> may have a radius approximately equal to, or exactly equal to, the third radius of the distal end <NUM> of the drive hub <NUM>. In this implementation, both the proximal and distal ends <NUM>, <NUM> of the drive hub <NUM> are sized to be able to move axially past the seal <NUM>.

The retention flange <NUM> and the seal <NUM> may be configured to be in an abutting relationship with one another to prevent the drive hub <NUM> from moving axially past the seal <NUM>, either directly or through intermediate structures. In particular, with the cutting assembly <NUM> not coupled to the drive assembly <NUM>, the retention flange <NUM> may the seal <NUM> in the second position, as shown in <FIG> and <FIG>. With the cutting assembly <NUM> removably coupled to the drive assembly <NUM>, the retention flange <NUM> may be spaced from the seal <NUM> in the first position, as shown in <FIG> and <FIG>.

The retention flange <NUM> may include a first retention surface <NUM> facing the seal <NUM>, and the seal <NUM> may include a second retention surface <NUM> facing the retention flange <NUM>. The first and second retention surfaces <NUM>, <NUM> may be configured to prevent the drive hub <NUM> from moving axially past the seal <NUM>. With the cutting assembly <NUM> is not removably coupled to the drive assembly <NUM> in the surgical instrument <NUM>, the first retention surface <NUM> of the retention flange <NUM> may abut the second retention surface <NUM> of the seal <NUM> in the second position. With the cutting assembly <NUM> removably coupled to the drive assembly <NUM> in the surgical instrument <NUM>, the drive hub <NUM> moves to the first position and the first retention surface <NUM> and the second retention surface <NUM> may be spaced apart from one another.

The outer hub <NUM> may be disposed at least partially about the outer tube <NUM>, the cutting shaft <NUM>, and the drive hub <NUM> to assist in removably coupling the cutting assembly <NUM> to the drive assembly <NUM>. The outer hub <NUM>, in a non-limiting example, may be engageable by a latching mechanism <NUM> to removably couple the cutting assembly <NUM> to the drive assembly <NUM>. In the implementations where the outer hub <NUM> has the proximal portion <NUM> defining the cavity <NUM> into which the drive hub <NUM> is received, the proximal portion <NUM> may have an expanded diameter portion <NUM> which at least partially defines the cavity <NUM>. The expanded diameter portion <NUM> of the proximal portion <NUM> of the outer hub <NUM> has a greater diameter as compared to other sections of the proximal portion <NUM> of the outer hub <NUM>. The expanded diameter portion <NUM> may be at a proximal end <NUM> of the proximal portion <NUM>. The expanded diameter portion <NUM> may be shaped as to form a step or a series of steps into the outer hub <NUM>. Alternatively, the expanded diameter portion <NUM> may be spaced from the proximal end <NUM> of the proximal portion <NUM>. In one example, the expanded diameter portion <NUM> may be shaped as to define a groove into the outer hub <NUM>.

The seal <NUM> also may be compressed when disposed within the cavity <NUM> defined by the proximal portion <NUM> of the outer hub <NUM>. The outer hub <NUM> may also define seating holes into which the seal <NUM> may at least partially extend. Although not required, the seal <NUM> may deform to at least partially be situated within the seating holes. The seating holes may prevent rotation of the seal <NUM> relative to the outer hub <NUM>. More specifically, the seal <NUM> may have a lip that extends at least partially into the seating holes to prevent rotation of the seal <NUM> relative to the outer hub <NUM>. The seal <NUM> may include a locking tab <NUM> engageable with the expanded diameter portion <NUM> of the proximal portion <NUM> of the outer hub <NUM>. The locking tab <NUM> of the seal <NUM> may extend radially away from the axis A relative to a body <NUM> of the seal <NUM>. The locking tab <NUM> also may be sized and configured to fit within the step or series of steps formed by the expanded diameter portion <NUM>, or may be sized and configured to fit within the groove defined by the expanded diameter portion <NUM> into the outer hub <NUM>.

The retention flange <NUM> may be capable of being unobstructed by the seal <NUM> radially between the drive hub <NUM> and the outer hub <NUM>. The retention flange <NUM> may be moveable between a first flange position and a second flange position. In the first flange position, as shown in <FIG>, the retention flange <NUM> is unobstructed by the seal <NUM> radially between the retention flange <NUM> and the outer hub <NUM>. In the second flange position, as shown in <FIG>, the retention flange <NUM> is obstructed by the seal <NUM> radially between the retention flange <NUM> and the outer hub <NUM> such that the seal <NUM> is disposed between the retention flange <NUM> and the outer hub <NUM>.

The retention flange <NUM> may extend completely circumferentially about the axis A to form a general disk shape. However, it is to be appreciated that the retention flange <NUM> may extend only partially about the axis A, or may extend radially away from the axis A at two or more points circumferentially spaced from one another about the axis A. It is also to be appreciated that the retention flange <NUM> may form a generally polygonal shape, such as, but not limited to, triangular, rectangular, pentagonal, hexagonal, heptagonal, or octagonal.

Although not required, the innermost point <NUM> of the seal <NUM> may be radially aligned with the locking tab <NUM> of the seal <NUM>. Said differently, the innermost point <NUM> of the seal <NUM> may be radially spaced from the locking tab <NUM> of the seal <NUM> such that the innermost point <NUM> of the seal <NUM> is disposed radially between the locking tab <NUM> of the seal <NUM> and the axis A. As such, the innermost point <NUM> of the seal <NUM> may be radially aligned with the expanded diameter portion <NUM> of the outer hub <NUM>. In one implementation, the innermost point <NUM> of the seal <NUM> is further defined as a first innermost point <NUM>, and the seal <NUM> has a second innermost point <NUM> relative to the drive hub <NUM>. The second innermost point <NUM> of the seal <NUM> may be circumferentially spaced from the first innermost point <NUM> of the seal <NUM> about the axis A. In other words, the first and second innermost points <NUM>, <NUM> of the seal <NUM> may be interrupted by circumferential sections of the seal <NUM> that are radially further away from the axis A than the first and second innermost points <NUM>, <NUM> of the seal <NUM>.

The seal <NUM> further includes a retaining flange <NUM> extending radially toward the axis A. The retention flange <NUM> of the drive hub <NUM> is configured to contact the retaining flange <NUM> of the seal <NUM> in the second position. The retaining flange <NUM> of the seal <NUM> assists in preventing the drive hub <NUM> from moving axially past the seal <NUM>. It is to be appreciated that the first and second innermost points <NUM>, <NUM> of the seal <NUM> may be disposed on the retaining flange <NUM>. Said differently, the retaining flange <NUM> may be the radially closest portion of the seal <NUM> to the axis A. The retention flange <NUM> of the drive hub <NUM> and the retaining flange <NUM> of the seal <NUM> may be configured to be in an abutting relationship with one another to prevent the drive hub <NUM> from moving axially past the seal <NUM>. The retaining flange <NUM> of the seal <NUM> may be disposed between the proximal and distal ends <NUM>, <NUM> of the seal <NUM>. As such, the drive hub <NUM> may be able to move along the axis A such that a portion of the drive hub <NUM> is axially past the seal <NUM>. However, it is also to be appreciated that the retention flange <NUM> of the drive hub <NUM> is not able to move axially past the seal <NUM>. As such, the retention flange <NUM> may be radially spaced from the seal <NUM> such that the seal <NUM> is disposed radially between the outer hub <NUM> and the drive hub <NUM>.

The retention flange <NUM> may be configured to be positioned between the distal end <NUM> of the seal <NUM> and the proximal portion <NUM> of the outer hub <NUM> when the drive hub <NUM>, and thus the cutting assembly <NUM>, is detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. More specifically, in the first position, the retention flange <NUM> may be positioned distal to the seal <NUM>. It is to be appreciated that the retention flange <NUM> need not be spaced completely distally past the seal <NUM> to be distal to the seal <NUM>. In a non-limiting example, only a portion of the retention flange <NUM> need be distal to the seal <NUM> for the retention flange <NUM> to be considered distal to the seal <NUM>. The retention flange <NUM> may be between the distal end <NUM> of the seal <NUM> and the proximal portion <NUM> of the outer hub <NUM> when the drive hub <NUM>, and thus the cutting assembly <NUM>, is detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. The retention flange <NUM> may be positioned at or adjacent to the distal end <NUM> of the seal <NUM> when the drive hub <NUM>, and thus the cutting assembly <NUM>, is detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. The retention flange <NUM> may be positioned at or adjacent to the distal end <NUM> of the seal <NUM> when the drive hub <NUM> is moved from the first position toward the second position.

The drive hub <NUM> and the cutting implement <NUM> may be movably slidable relative to the outer hub <NUM> when the cutting assembly <NUM> is not detachably coupled with the drive assembly <NUM> of the surgical instrument <NUM>. The drive hub <NUM> and the cutting implement <NUM> may be rigidly coupled to one another and thus may move in unison. Moreover, the drive hub <NUM> and the cutting implement <NUM> may also be movably slidable relative to the outer tube <NUM> of the cutting assembly <NUM>. As such, the retention flange <NUM> of the drive hub <NUM> and the retaining flange <NUM> of the seal <NUM> are necessary to prevent the drive hub <NUM> from moving axially past the seal <NUM>, and thus to maintain the drive hub <NUM> as ready for engagement with the drive assembly <NUM>.

In certain implementations, the cutting shaft <NUM> is an inner tube <NUM> defining a lumen <NUM> and rotatably disposed within the outer tube <NUM> such that the distal cutting end <NUM> is a cutting window <NUM> adapted to be applied to the surgical site of the patient. In other words, the surgical instrument <NUM> may be a shaver, particularly a shaver. The lumen <NUM> may be in fluid communication with the cutting window <NUM>. Alternatively, in another implementation as shown in <FIG>, the cutting shaft <NUM> is solid and the distal cutting end <NUM> is a bur <NUM>. The bur <NUM> on a cutting shaft <NUM> that defines the lumen <NUM> is also contemplated. The cutting shaft <NUM>, including the inner tube <NUM>, and outer tube <NUM> may be made of a metal material such as stainless steel or a non-metallic material such as a composite depending on the application. A wall thickness of the cutting shaft <NUM>, including the inner tube <NUM>, and the outer tube <NUM> is relatively thin such as approximately <NUM> to approximately <NUM> millimeters (mm) to be of a relatively small diameter and also to be lightweight. The diameters of the cutting shaft <NUM>, including the inner tube <NUM>, and the outer tube <NUM> have a relatively small diameter such as approximately <NUM> to approximately <NUM> so as to work in a small opening of a nasal cavity or oral cavity of the patient and to prevent the practitioner's view from being obstructed. It is contemplated that the cutting shaft <NUM>, particularly the inner tube <NUM>, and the outer tube <NUM> may be scaled larger or smaller depending on the application.

Referring now to <FIG> and <FIG>, the cutting assembly <NUM> may further include an irrigation spacer <NUM> disposed distal to the drive hub <NUM>. In implementations where the cutting assembly <NUM> is a shaver, closed distal end prevents distal movement of the cutting shaft <NUM> relative to the outer tube <NUM>. Such a constraint may not be present on a bur, and in particular the bur of <FIG> where the outer tube <NUM> defines a distal tube opening <NUM>. <FIG> shows the outer hub <NUM> defining an irrigation aperture <NUM> in fluid communication with the cavity <NUM> and an annular gap between the outer tube <NUM> and the cutting shaft <NUM> The irrigation aperture <NUM> may be an annular gap surrounding the cutting shaft <NUM>. The irrigation aperture <NUM> may be in fluid communication with the irrigation channel <NUM> defined between the drive hub <NUM> and the seal <NUM>. The distal end <NUM> of the drive hub <NUM>, positioned adjacent the irrigation aperture <NUM> (with distal movement of the cutting shaft <NUM>), may limit or occlude the flow of fluid through the irrigation aperture <NUM>. The irrigation spacer <NUM> of the present implementation advantageously provides for axial spacing of the drive hub <NUM> from near the irrigation aperture <NUM> while also providing irrigation passageways <NUM> to permit robust fluid flow to the irrigation aperture <NUM>. The irrigation passageways <NUM> may be in fluid communication with the irrigation channel <NUM> defined between the drive hub <NUM> and the seal <NUM> and the irrigation aperture <NUM> defined by the irrigation spacer <NUM>. To prevent the drive hub <NUM> from moving distal to the outer hub <NUM>, an outer diameter of the drive hub <NUM> is greater than an outer diameter of the irrigation aperture <NUM>.

As shown in <FIG>, the irrigation spacer <NUM> may include an inner irrigation spacer surface <NUM> facing the axis A. The inner irrigation spacer surface <NUM> may extend at least partially circumferentially about the axis A at a first radial distance D1. The inner irrigation spacer surface <NUM> may define a bore <NUM> through which the outer tube <NUM> is disposed. Moreover, the irrigation spacer <NUM> may include an outer irrigation spacer surface <NUM> facing away from the axis A. The outer irrigation spacer surface <NUM> may extend at least partially circumferentially about the axis A at a second radial distance D2. It is to be appreciated that the second radial distance D2 is greater than the first radial distance D1. In other words, the outer irrigation spacer surface <NUM> may be spaced from the inner irrigation spacer surface <NUM> such that the inner irrigation spacer surface <NUM> is disposed radially between the axis A and the outer irrigation spacer surface <NUM>.

The irrigation spacer <NUM> may define the irrigation passageway <NUM> between the first and second radial distances D1, D2. The irrigation passageway <NUM> may also be configured to be in fluid communication with the handpiece irrigation path <NUM> defined by the handpiece <NUM> of the drive assembly <NUM>. The irrigation passageway <NUM> allows irrigating fluid to pass through the irrigation spacer <NUM>. More specifically, irrigating fluid may flow from the handpiece irrigation path <NUM> defined by the handpiece <NUM> to the distal opening <NUM> of the handpiece <NUM>, optionally through the irrigation channel <NUM> defined between the drive hub <NUM> and the seal <NUM> if present in the implementation, through the irrigation passageway <NUM> defined by the irrigation spacer <NUM> if present in the implementation, through the irrigation aperture <NUM> defined by the outer hub <NUM>, through the irrigation flow path <NUM> defined between the outer tube <NUM> and the cutting shaft <NUM> of the cutting assembly <NUM>, and finally to the surgical site of the patient. The irrigation spacer <NUM> may be formed from plastic, including injection-molded plastic, but other suitable materials including, metal, ceramic, and composite materials.

The outer hub <NUM> may be disposed in the cavity <NUM> defined by the proximal portion <NUM> of the outer hub <NUM>. As shown in <FIG> and <FIG>, the outer hub <NUM> may have an inner hub surface <NUM> that tapers distally toward the axis A. Said differently, the inner hub surface <NUM> may have a smaller diameter at the distal end of the inner hub surface <NUM> and may have a larger diameter at the proximal end of the inner hub surface <NUM>. The outer irrigation spacer surface <NUM> of the irrigation spacer <NUM> may taper distally toward the axis A. Said differently, the outer irrigation spacer surface <NUM> may have a smaller diameter at the distal end of the outer irrigation spacer surface <NUM> and may have a larger diameter at the proximal end of the outer irrigation spacer surface <NUM>. The inner hub surface <NUM> and the outer irrigation spacer surface <NUM> may be engageable with one another to maintain a relative axial position between the outer hub <NUM> and the irrigation spacer <NUM>. In a non-limiting example, that the inner hub surface <NUM> and the outer irrigation spacer surface <NUM> may be press-fit with one another. Alternatively, tapered profiles of the inner hub surface <NUM> and the outer irrigation spacer surface <NUM> may only loosely fit together, and may aid in manufacturability and/or assembly of the cutting assembly <NUM> of the surgical instrument <NUM>.

In the illustrated implementation, the irrigation spacer <NUM> may have a hub <NUM> that defines the bore <NUM>, and fins <NUM> extending radially away from the hub <NUM>. The fins <NUM> may be spaced circumferentially about the axis A and may define the irrigation passageway <NUM>. The irrigation spacer <NUM> may have two, three, four, five, six, seven, eight, or more than eight fins <NUM>. As such, the outer irrigation spacer surface <NUM> may be interrupted to not extend completely circumferentially about the axis A. Other configures of the irrigation spacer <NUM> are contemplated to provide the irrigation passageways <NUM>, including those without the fins <NUM> in the implementation. In another example, the outer irrigation spacer surface <NUM> may extend completely circumferentially about the axis A at the second radial distance D2 without interruption.

The outer hub <NUM> may have a key <NUM> that extends at least partially into the irrigation passageway <NUM> to limit rotation of the irrigation spacer <NUM> relative to the outer hub <NUM>. The key <NUM> thus may be characterized as an anti-rotation feature. Preventing rotation between the irrigation spacer <NUM> and the outer hub <NUM> assists in maintaining alignment of the irrigation spacer <NUM>, the outer hub <NUM>, the outer tube <NUM>, and the drive hub <NUM> to ensure proper operation of the surgical instrument. The key <NUM> also prevents the irrigation spacer <NUM> from rotating with the cutting shaft <NUM>.

The irrigation spacer <NUM> may be engageable with the drive hub <NUM> and the irrigation spacer <NUM> may be configured to cooperate with the drive assembly <NUM> to maintain a relative axial position between the bur <NUM> and the distal tube opening <NUM>. In other words, the irrigation spacer <NUM> may assist in spring-loading the bur <NUM>. A thickness of the irrigation spacer <NUM> may be selectively designed for a given length of the cutting implement <NUM> to position the bur <NUM> at a desired distance beyond the distal tube opening <NUM>. An internal biasing member (not identified) may be configured to urge the drive hub <NUM> into engagement with the irrigation spacer <NUM>. The cutting assembly <NUM> may further include at least one washer <NUM> disposed between the irrigation spacer <NUM> and the drive hub <NUM> to assist the desired stack up. For example, the at least one washer <NUM> may be one, two, three washers, or four or more washers to bear against one another to control axial movement of the irrigation spacer <NUM> as desired.

The drive assembly <NUM> for the surgical instrument <NUM> includes the handpiece <NUM> extending along the axis A. The handpiece <NUM> includes a distal end <NUM> defining a distal opening <NUM> inwardly from the distal end <NUM> that is dimensioned to receive the outer hub <NUM> of the cutting assembly <NUM>. The handpiece <NUM> also includes a proximal end <NUM> defining a proximal opening <NUM> inwardly from the proximal end <NUM>. A back cap <NUM> is coupled to the handpiece <NUM> so as to be at least partially disposed within the proximal opening <NUM>. A motor <NUM> is disposed within the handpiece <NUM>. The motor <NUM> has an output shaft <NUM> rotatable about the axis A, and a coupling member <NUM> is attached to the output shaft <NUM> for releasably coupling the drive hub <NUM> of the cutting assembly <NUM> to the output shaft <NUM> such that the output shaft <NUM> and the drive hub <NUM> rotate in unison.

The drive assembly <NUM> also includes an irrigation port <NUM> coupled to the handpiece <NUM> and configured be removably coupled to an irrigation tube. The drive assembly <NUM> further includes a suction port <NUM> coupled to the back cap <NUM> and configured to be removably coupled to a suction tube. A proximal end <NUM> of the irrigation port <NUM> is positioned distal to a position where the suction port <NUM> is coupled to the back cap <NUM> so as to limit obstruction from the irrigation port <NUM> when coupling the suction tube to the suction port <NUM>.

The placement of the suction port <NUM> and the irrigation port <NUM> results in the suction and irrigation tubes being spaced apart from one another. Therefore, regardless of whether the suction tube is removably coupled to the suction port <NUM> before or after the irrigation tube is removably coupled to the irrigation port <NUM>, the irrigation and suction tubes are less likely to interfere with one another. Furthermore, the placement of the suction and irrigation ports <NUM>, <NUM> in provides adequate clearance for a practitioner's hand <NUM> for ease with coupling the suction and irrigation tubes to the suction and irrigation ports <NUM>, <NUM>, respectively.

In one implementation, the irrigation port <NUM> includes a distal end <NUM> coupled to the handpiece <NUM> and the proximal end <NUM> opposite the distal end <NUM>. The suction port <NUM> includes a distal portion <NUM> disposed within and coupled to the handpiece <NUM>. More specifically, the distal portion <NUM> of the suction port <NUM> may be disposed within and coupled to the back cap <NUM> of the handpiece <NUM>. The suction port <NUM> also includes a proximal portion <NUM> extending proximally from the handpiece <NUM>. More specifically, a proximal portion <NUM> of the suction port <NUM> may extend proximally from the back cap <NUM> of the handpiece <NUM>. The proximal end <NUM> of the irrigation port <NUM> is positioned axially distal to the proximal portion <NUM> of the suction port <NUM>. For convention, as shown in <FIG> by a dotted line B, the proximal end <NUM> of the irrigation port <NUM> may be axially distal to the proximal portion <NUM> of the suction port <NUM>. Said differently, the proximal portion <NUM> of the irrigation port <NUM> may be considered to begin where the irrigation port <NUM> extends from the back cap <NUM>, and the proximal portion <NUM> of the suction port <NUM> may be axially distal to where the irrigation port <NUM> extends from the back cap <NUM> (i.e., axially distal to the dotted line B in <FIG>).

The irrigation port <NUM> and the suction port <NUM> may have a barb configuration to assist in removably coupling the irrigation and suction tubes to the irrigation and suction ports <NUM>, <NUM>. It is to be appreciated that a clamp or other mechanical fastener may be used to assist in removably coupling the irrigation and suction tubes to the irrigation and suction ports <NUM>, <NUM>.

The drive assembly <NUM> may further include an electrical connector <NUM> coupled to the handpiece <NUM> and configured to be coupled to a source of electrical power to power the motor <NUM>. The source of electrical power may be a corded connection <NUM>. The electrical connector <NUM> may be disposed in, or directly attached to, the back cap <NUM> of the handpiece <NUM>. The electrical connector <NUM> may be screwed into the back cap <NUM> of the handpiece <NUM> to secure the electrical connector <NUM> to the drive assembly <NUM>. Other means of coupling are contemplated, for example, press-fit, welding, or otherwise mechanically affixed to the back cap <NUM> of the handpiece <NUM>. Alternatively, it is to be appreciated that the motor <NUM> of the surgical instrument <NUM> may instead be powered by a battery disposed within the surgical instrument <NUM>.

A proximal end <NUM> of the electrical connector may be spaced from the proximal portion <NUM> of the suction port <NUM> such that the suction port <NUM> is disposed axially between the electrical connector <NUM> and the irrigation port <NUM>. In other words, in order from a proximal end <NUM> of the surgical instrument <NUM> to a distal end <NUM> of the surgical instrument <NUM>, the irrigation port <NUM>, the suction port <NUM>, and the electrical connector <NUM> may be spaced from one another along the axis A, respectively. The back cap <NUM> may at least partially define an electrical channel <NUM> through which electrical wires may travel to power the motor <NUM>. It is to be appreciated that the back cap <NUM> may completely define the electrical channel <NUM>. Optionally, the handpiece <NUM> may at least partially define the electrical channel through which the electrical power may travel to power the motor <NUM>.

The handpiece <NUM> may also define the handpiece irrigation path <NUM> in fluid communication with the irrigation port <NUM> and with the proximal opening <NUM> of the handpiece <NUM> to provide irrigating fluid between the outer tube <NUM> and the cutting shaft <NUM> of the cutting assembly <NUM>. More specifically, irrigating fluid may flow through the irrigation tube to the irrigation port <NUM>, through the handpiece irrigation path <NUM> to the distal opening <NUM> of the handpiece <NUM>, through the irrigation channel <NUM> defined between the drive hub <NUM> and the seal <NUM> of the cutting assembly <NUM>, between the outer tube <NUM> and the cutting shaft <NUM> of the cutting assembly <NUM>, and finally to the surgical site of the patient.

The output shaft <NUM> and the coupling member <NUM> may together define a suction flow path <NUM> in fluid communication with the suction port <NUM> to provide vacuum pressure to the drive hub <NUM> of the cutting assembly <NUM>. The drive hub <NUM>, particularly the bore <NUM> defined by the drive hub <NUM>, may be in fluid communication with the cutting shaft <NUM>, particularly the lumen <NUM> of the inner tube <NUM>, to provide the vacuum pressure to the surgical site. The back cap <NUM> may have a suction portion <NUM> adjacent to the suction port <NUM> and an electrical portion <NUM> adjacent to the electrical connector <NUM>. The suction portion <NUM> may be spaced from the proximal end <NUM> of the irrigation port <NUM> such that the suction portion <NUM> is disposed axially between the electrical portion <NUM> and the proximal end <NUM> of the irrigation port <NUM>. The irrigation port <NUM>, therefore, may be axially distal relative to the back cap <NUM>. The suction port <NUM> may be generally aligned with the axis A and disposed at a general radial center <NUM> relative to the handpiece <NUM>. The suction port <NUM> may be disposed at the general radial center <NUM> relative to the handpiece <NUM> to assist in removing the bits of sinus bone and tissue from the surgical site of the patient. More specifically, the suction port <NUM>, the suction flow path <NUM>, the drive hub <NUM>, and the lumen of the inner tube <NUM> may lie in a general line parallel to the axis A through the general radial center <NUM> relative to the handpiece <NUM> to prevent clogging of the surgical instrument <NUM>.

The lumen of the inner tube <NUM>, the drive hub <NUM>, the suction flow path <NUM>, and the suction port <NUM> may generally increase in diameter from the distal end <NUM> of the surgical instrument <NUM> to the proximal end <NUM> of the surgical instrument <NUM>. Additionally, as shown in <FIG>, the suction port <NUM> may have a larger internal diameter as compared to the internal diameter of the suction flow path <NUM> defined by the output shaft <NUM>. More specifically, an interface between the suction port <NUM> and the output shaft <NUM> may be sized such that the larger internal diameter of the suction port <NUM> as compared to the internal diameter of the suction flow path <NUM> defined by the output shaft <NUM> to further prevent clogging of the surgical instrument <NUM>.

The irrigation port <NUM> may be generally aligned with the axis A and disposed radially spaced from the general radial center <NUM> relative to the handpiece <NUM>. Said differently, the irrigation port <NUM> may extend generally parallel to the axis A. The irrigation port <NUM> is able to be disposed radially spaced from the general radial center <NUM> relative to the handpiece <NUM>, while still allowing adequate flow of irrigating fluid to the surgical site of the patient.

The electrical connector <NUM> may be generally aligned with the axis A and disposed radially spaced from the general radial center <NUM> relative to the handpiece <NUM>. More specifically, the suction port <NUM> may be spaced radially between the electrical connector <NUM> and the irrigation port <NUM>. In this way, the electrical connector <NUM> may be spaced apart from the irrigation port <NUM> to avoid the irrigating fluid from interacting with the electrical power, thus avoiding damage to the surgical instrument <NUM>.

The handpiece <NUM> for the surgical instrument <NUM> may be configured to be handled by the hand <NUM> including a middle finger <NUM>, an index finger <NUM>, a thumb <NUM>, and a web <NUM> between the index finger <NUM> and the thumb <NUM>. The handpiece <NUM> may include a handle body <NUM> including a proximal end <NUM> opposite a distal end <NUM>. The handle body <NUM> may define a longitudinal axis A. The handle body <NUM> may also include a saddle region <NUM> near the proximal end <NUM> of the handpiece.

The saddle region <NUM> may define a first recess <NUM>, may be configured to be situated upon the web <NUM> of the hand <NUM> to support the handpiece <NUM>, and may define a lower aspect <NUM> of the handpiece <NUM> in an operative orientation. The lower aspect <NUM> may further include a curved surface <NUM> between the saddle region <NUM> and the distal end <NUM> of the handle body <NUM>. The handle body <NUM> may define a second recess <NUM> near the distal end <NUM> of the handle body <NUM> and extending annularly about the longitudinal axis A. The second recess <NUM> may be configured to accommodate at least the index finger <NUM> and the middle finger <NUM> of the hand <NUM> in a pencil-grip arrangement in the operative orientation. The pencil-grip arrangement allows the practitioner to maneuver the handpiece <NUM>.

The handle body <NUM> may further include an apex region <NUM> extending longitudinally between the second recess <NUM> and the proximal end <NUM>. The apex region <NUM> assists the practitioner in handling the surgical instrument <NUM>. It is to be appreciated that the apex region <NUM> extends on either side of the surgical instrument <NUM> to assist both left-handed and right-handed practitioners in handling the surgical instrument <NUM>. The apex region <NUM> may include opposing surfaces <NUM>, <NUM> that are relatively flatter than the curved surface <NUM> of the lower aspect <NUM>. The opposing surfaces <NUM>, <NUM> are on either side of the surgical instrument <NUM>. The opposing surfaces <NUM>, <NUM> may be angling towards and meeting one another to define an upper aspect <NUM> of the handpiece <NUM> in the operative orientation. Optionally, the handle body <NUM> may further define a third recess <NUM> extending longitudinally along at least a portion of the opposing surfaces <NUM>, <NUM> and configured to provide a grip for the thumb <NUM> of the hand <NUM> in the pencil-grip arrangement.

In some implementations, the apex region <NUM> defines the handpiece irrigation path <NUM> internal to the handle body <NUM>. Moreover, in some implementations, the handpiece <NUM> further includes the irrigation port <NUM> coupled to the apex region <NUM> and in fluid communication with the handpiece irrigation path <NUM>. As shown in <FIG> and <FIG>, the apex region <NUM> may be triangular in axial section, or a variety of shapes in including, but not limited to, parabolic, curvilinear, oval, and rectangular. In implementations where the handpiece <NUM> includes the back cap <NUM>, the electrical connector <NUM> may be positioned on the back cap <NUM> opposite the saddle region <NUM> to orient the handpiece <NUM> in the operative orientation with the saddle region <NUM> supported by the hand of the user.

The drive assembly <NUM> may include a collet <NUM> coupled to the handpiece <NUM> and configured to receive the cutting assembly <NUM> to form the surgical instrument <NUM>. The collet <NUM> may be unitary in construction between its ends and shaped to accommodate the outer hub <NUM> and the seal <NUM> of the cutting assembly <NUM>. In particular, a proximal portion <NUM> of the collet <NUM> may be unitary construction to form a curved surface configured to be positioned in an abutting relationship with the proximal end <NUM> of the seal <NUM>, as shown in <FIG> and <FIG>. The abutting relationship prevents egress of irrigation fluid within the irrigation flow path. Further, the proximal portion being unitary in construction obviates the need for discrete sleeves or other subcomponents that could otherwise provide interfaces for inadvertent egress of fluid. The collet <NUM> may include an O-ring <NUM> positioned with a recess defined by the proximal portion <NUM> to provide an additional seal between the collet <NUM> and the distal opening <NUM> of the handpiece <NUM>.

The collet <NUM> may be coupled to the handpiece <NUM> with engagement tabs <NUM> (one shown) with complementary slots defined by the handpiece <NUM>. The tabs <NUM> may be two tabs that subtend different length arcs, wherein the slots similarly subtend complementary arcs. The arrangement requires the collet <NUM> be engaged with the handpiece <NUM> in a single orientation such that a button <NUM> of the latching mechanism <NUM> is aligned radially with the upper aspect <NUM> of the handpiece <NUM> in the operative orientation. To assemble the collet <NUM> with the handpiece <NUM> the engagement tabs <NUM> are inserted through the corresponding slots, and the collet <NUM> is rotated into a locked position. The tabs-in-slots arrangement obviates the need for set screws, which may further obviate the need for sealant over the holes through which the set screws are disposed. Another exemplary collet is disclosed in commonly-owned <CIT>.

Claim 1:
A cutting assembly (<NUM>) for a surgical instrument (<NUM>) including a drive assembly (<NUM>), and a handpiece (<NUM>) defining a handpiece irrigation path (<NUM>) and a suction flow path (<NUM>), said cutting assembly (<NUM>) comprising:
an outer hub (<NUM>) defining a cavity (<NUM>);
an outer tube (<NUM>) extending from said outer hub (<NUM>);
a cutting implement (<NUM>) comprising a cutting shaft (<NUM>) rotatably disposed within said outer tube (<NUM>), and a distal cutting end (<NUM>), said cutting shaft (<NUM>) defining a lumen (<NUM>), wherein an irrigation flow path (<NUM>) is defined between said outer tube (<NUM>) and said cutting shaft (<NUM>); and
a drive hub (<NUM>) coupled to a proximal end (<NUM>) of said cutting shaft (<NUM>) and configured to be removably coupled with the drive assembly (<NUM>) for rotating said cutting shaft (<NUM>) within said outer tube (<NUM>), said drive hub (<NUM>) comprising a retention flange (<NUM>) and defining a bore (<NUM>) in fluid communication with said lumen (<NUM>) of said cutting shaft (<NUM>), wherein said lumen (<NUM>) and said bore (<NUM>) are configured to be arranged in fluid communication with the suction flow path (<NUM>) of the handpiece (<NUM>); and
a seal (<NUM>) coupled to said outer hub (<NUM>) and at least partially disposed within said cavity (<NUM>),
wherein said retention flange (<NUM>) is configured to be spaced apart from a distal end (<NUM>) of said seal (<NUM>) with said drive hub (<NUM>) removably coupled to the drive assembly (<NUM>) of the surgical instrument (<NUM>) to permit fluid to flow from the handpiece irrigation path (<NUM>) to said irrigation flow path (<NUM>) through said cavity (<NUM>) between said drive hub (<NUM>) and said seal (<NUM>).