Patent Description:
The present invention relates to a surgical cutting device and, more particularly, to a shaver bur having a retractable bur tip.

Shaver burs are surgical cutting instruments having a sharp flute intended to "shave" or resect bone inside the joint during arthroscopic procedures. Surgical shaver burs are comprised of an inner and an outer assembly. The outer assembly is composed of a hollow steel tube, which is bonded to a molded plastic hub on the proximal end and contains a cut out or open hood on the distal end. The inner assembly is housed within the outer assembly and comprises an inner tube. The inner tube is composed of a hollow steel tube, which is bonded to a molded plastic hub on the proximal end and welded to a shaver bur tip on the distal end.

In use, the bur tip will spin forward, backward, or oscillate while the outer assembly remains stationary. In traditional shaver burs, the bur tip is permanently exposed. As a result, during arthroscopic procedures, the sharp cutting edges of the bur trip occasionally and unintentionally contact articular surfaces within the joint space. This contact can cause damage and injury to the patient at the surgical site.

Therefore, there is a need for a shaver bur with a protectable bur tip to improve operation conditions.

A surgical cutting instrument with the features of the pre-characterizing portion of Claim <NUM> is disclosed in <CIT>. Further surgical instrument related to the one of the present invention are disclosed in <CIT>, <CIT>, <CIT> and <CIT>.

Description of the Related Art Section Disclaimer: To the extent that specific patents/publications/products are discussed above in this Description of the Related Art Section or elsewhere in this disclosure, these discussions should not be taken as an admission that the discussed patents/publications/products are prior art for patent law purposes. For example, some or all of the discussed patents/publications/products may not be sufficiently early in time, may not reflect subject matter developed early enough in time and/or may not be sufficiently enabling so as to amount to prior art for patent law purposes.

The present disclosure is directed to a shaver bur for resecting bone inside the joint in arthroscopic procedures. The shaver bur of the present invention is defined in Claim <NUM>. Further advantageous features are set out in the dependent claims.

The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings. The accompanying drawings illustrate only typical embodiments of the disclosed subject matter and are therefore not to be considered limiting of its scope, for the disclosed subject matter may admit to other equally effective embodiments. Reference is now made briefly to the accompanying drawings, in which:.

Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in <FIG>, a perspective view schematic representation of a retractable shaver bur <NUM>, according to an embodiment. The shaver bur <NUM> includes a proximal outer hub assembly <NUM> with an outer tube <NUM> (see, also <FIG>) extending distally therefrom along a central longitudinal y - y axis. The outer hub assembly <NUM> extends to and comprises a proximal end <NUM> and the outer tube <NUM> extends to and comprises a distal end <NUM> of the shaver bur <NUM>, as shown in <FIG>. The shaver bur <NUM> comprises a proximal inner assembly <NUM> coupled to a distal outer assembly <NUM>.

Turning now to <FIG>, there is shown a perspective view schematic representation of the inner assembly <NUM> of the shaver bur <NUM>, according to an embodiment. The inner assembly <NUM> includes an inner hub <NUM> connected to a proximal end cap <NUM>. In an embodiment, the proximal end cap <NUM> is removably attached to the inner hub <NUM>. In an alternative embodiment, the proximal end cap <NUM> is bonded to the inner hub <NUM>. As shown in <FIG>, the inner hub <NUM> and the proximal end cap <NUM> are substantially cylindrical.

Still referring to <FIG>, the inner hub <NUM> comprises a cylindrical central body <NUM> with a central connecting tube <NUM> extending therefrom in the distal direction. The inner hub <NUM> also includes a key portion <NUM> extending from the central body <NUM> in the proximal direction. The key portion <NUM> includes one or more features <NUM> for connecting the inner hub <NUM> to the proximal end cap <NUM> (<FIG>). As shown in <FIG>, the inner hub <NUM> is connected to an inner tube <NUM>. The central connecting tube <NUM> extending distally from the inner hub <NUM> is cannulated and configured or otherwise adapted to receive the inner tube <NUM>, as shown in <FIG>. In the depicted embodiment, the inner tube <NUM> is solid. The inner tube <NUM> can be composed of steel and/or other similar hard metals. The inner tube <NUM> extends to and includes a distal bur tip <NUM>. The bur tip <NUM> is used to shave or resect bone inside a joint during arthroscopic procedures.

Referring now to <FIG>, there is shown a perspective view schematic representation of the outer assembly <NUM> of the shaver bur <NUM>, according to an embodiment. The outer assembly <NUM> includes a cylindrical outer hub <NUM> connected to the cannulated outer tube <NUM>. As recited above, the cannulated outer tube <NUM> extends distally from the outer hub <NUM>. In an embodiment, the outer hub <NUM> is bonded to the cannulated outer tube <NUM>. The cannulated outer tube <NUM> comprises an open distal end <NUM>. In the depicted embodiment, the open distal end <NUM> is angled such that a plane x - x extending over the open distal end <NUM> is at an angle relative to the central longitudinal y - y axis. In the depicted embodiment, the plane a - a is at an angle less than <NUM> degrees relative to the central longitudinal y - y axis.

Turning now to <FIG>, there is shown an exploded perspective view schematic representation of the outer hub assembly <NUM>, according to an embodiment. As described above, the outer hub assembly <NUM> includes the inner hub <NUM> of the inner assembly <NUM> and the outer hub <NUM> of the outer assembly <NUM>. Between the inner hub <NUM> and the outer hub <NUM> is a magnet retainer <NUM>. The magnet retainer <NUM> is cylindrical with a central bore <NUM> extending therethrough. The magnet retainer <NUM> additionally comprises one or more stems <NUM> (e.g., rods) extending distally therefrom. As shown in <FIG>, the stems <NUM> extend from a distal end <NUM> of the magnet retainer <NUM> toward the outer hub <NUM>. The purpose of the magnetic retainer <NUM> is to allow for identification of the type of blade or bur used with a handpiece (not shown) connected to the outer hub assembly <NUM>. The magnetic retainer <NUM> can convey information to the handpiece and connected control system (not shown) so that appropriate signals may be generated by the control system to optimize attachments for certain procedures requiring varying speeds and torques. The signals may also alter the operation of buttons on the handpiece (e.g., toggle, momentary on/off, etc.).

Referring briefly to <FIG>, there is shown a perspective view schematic representation of the inner hub <NUM> coupled to the outer hub <NUM>, according to an embodiment. As shown in <FIG>, the inner hub <NUM> is coupled to the outer hub <NUM> with the magnet retainer <NUM> therebetween. The outer hub <NUM> comprises one or more slots <NUM> extending at least partially therethrough along the central longitudinal y - y axis (<FIG>). In the depicted embodiment, the slots <NUM> extend entirely through the outer hub <NUM>. When the outer hub assembly <NUM> is assembled, the central connecting tube <NUM> of the inner hub <NUM> extends through the central bore <NUM> of the magnet retainer <NUM> (<FIG>). The one or more stems <NUM> of the magnet retainer <NUM> extend into the one or more slots <NUM> of the outer hub <NUM>. The outer hub <NUM> includes a central bore <NUM> configured or otherwise adapted to receive the inner tube <NUM>.

Turning back to <FIG>, the outer hub assembly <NUM> additionally comprises a deployment mechanism <NUM>. In the depicted embodiment, the deployment mechanism <NUM> is a "twist ring. " The twist ring <NUM> is a rotatable circular piece, such as a disk, cap, or plate. In the depicted embodiment, the twist ring <NUM> is a rotatable, cylindrical disk with a central bore <NUM> extending therethrough. The twist ring <NUM> is attached to a distal end <NUM> of the outer hub <NUM> and abuts (or is adjacent to) the one or more stems <NUM> of the magnet retainer <NUM>. The twist ring <NUM> functions to extend and retract the distal bur tip <NUM> (<FIG>). In the embodiment in <FIG>, the twist ring <NUM> comprises a plurality of ridges <NUM> extending along its outer circumference <NUM>. The ridges <NUM> allow a user to get a firm grip on the twist ring <NUM> to rotate it.

Turning now to <FIG> and <FIG>, there are shown side views schematic representations of the shaver bur <NUM> in a retracted position and an extended position, respectively, according to an embodiment. In the retracted position, the inner tube <NUM> with the distal bur tip <NUM> is retracted and protected within the outer tube <NUM>, as shown in <FIG>. From the retracted position, the twist ring <NUM> is rotated in a first direction (e.g., counter-clockwise). As the twist ring <NUM> rotates in the first direction, the inner assembly <NUM> moves axially along the central longitudinal y - y axis toward the distal end <NUM> of the outer tube <NUM>, sliding the inner tube <NUM> distally from the outer tube <NUM>. The twist ring <NUM> is rotated in the first direction until the bur tip <NUM> is exposed and ready for use, as shown in <FIG>.

When use of the bur tip <NUM> is complete, the twist ring <NUM> is rotated in a second direction (e.g., clockwise). As the twist ring <NUM> rotates in the second direction, the twist ring <NUM> pushes against the one or more stems <NUM>, which in turn, engage the inner assembly <NUM>. Specifically, the stems <NUM> on the magnet retainer <NUM> are engaged and move axially and proximally along the central longitudinal y - y axis toward the proximal end <NUM> of the shaver bur <NUM>. The magnet retainer <NUM> engages the inner hub <NUM>, which is bonded to the inner tube <NUM>. The entire inner assembly <NUM>, including the bur tip <NUM>, moves axially toward the proximal end <NUM> of the shaver bur <NUM>. As a result, the bur tip <NUM> is fully retracted within the outer tube <NUM>, as shown in <FIG>.

The use of the twist ring <NUM> as the deployment mechanism allows the user to make fine-tune adjustments, permitting the bur tip to be completely exposed, fully retracted, or at some position therebetween. In an alternative embodiment, the twist ring <NUM> may also comprise a knob or other handle-like feature for rotating the twist ring <NUM>. In another embodiment, the deployment mechanism <NUM> is a lever or latch assembly that, when moved from a first position to a second position, causes the bur tip <NUM> to move from the retracted position to the extended position. In yet another embodiment, the deployment mechanism <NUM> is an on/off button or an actuator button that when pressed, moves the bur tip <NUM> from the retracted position to the extended position. Similarly, the on/off button can operate such that it must be held down in the pressed state to maintain the bur tip <NUM> in the extended (or retracted) position. In an additional embodiment, the deployment mechanism <NUM> is a release ring that is pulled in the proximal direction to either move the outer tube <NUM> proximally over the inner tube <NUM>, exposing the bur tip <NUM> or move the inner tube <NUM> in the distal direction out from the outer tube <NUM>, exposing the bur tip <NUM>. The release ring (and other embodiments of the deployment mechanism <NUM>) can be used in conjunction with a locking mechanism that locks the shaver bur <NUM> in the retracted and/or extended positions.

Claim 1:
A shaver bur (<NUM>), comprising:
an inner assembly (<NUM>) having an inner hub (<NUM>) with an inner tube (<NUM>) extending distally therefrom, the inner tube (<NUM>) terminating in a distal bur tip (<NUM>);
an outer assembly (<NUM>) having an outer hub (<NUM>) with an outer tube (<NUM>) extending distally therefrom;
wherein the inner tube (<NUM>) is moveable within the outer tube (<NUM>) between a retracted position and an extended position;
a deployment mechanism (<NUM>) connected to the outer hub (<NUM>), the deployment mechanism movable in a first direction and a second direction; and
wherein moving the deployment mechanism in a first direction moves the inner tube (<NUM>) to the extended position and moving the deployment mechanism in a second direction moves the inner tube (<NUM>) to the retracted position;
characterized in that
the outer hub (<NUM>) comprises one or more slots (<NUM>) extending at least partially through it,
the shaver bur (<NUM>) further comprises a magnet retainer (<NUM>) connected between the inner hub (<NUM>) and the outer hub (<NUM>) and comprising one or more stems (<NUM>) extending from it;
each of the one or more stems (<NUM>) extends through one of the one or more slots (<NUM>) in the outer hub (<NUM>);
the deployment mechanism (<NUM>) abuts the one or more stems (<NUM>) of the magnet retainer (<NUM>); and
moving the deployment mechanism in the second direction moves the deployment mechanism (<NUM>) against the magnet retainer (<NUM>) and moves the inner assembly (<NUM>) axially in the proximal direction.