Patent Description:
When cutting a patient's bone, in particular during the bone preparation phase of a joint replacement surgery, such as, for instance, a total knee arthroplasty, a surgeon uses a well-known surgical cutting tool, usually a sagittal saw. Such a tool includes an oscillating blade which oscillates within a plane P known as the cutting plane P. During the cutting operation, the surgeon may apply a certain force/pressure on the tool. Under this pressure, the blade, due to its thinness, tends to buckle (bend) when touching the bone, causing the blade to deviate from the original cutting plane. The aim of the current invention is to reduce this bending effect in order to keep the blade as close as possible to the cutting plane P.

In order to do so, the current application is about a retractable cutting guide.

A cutting guide for the saw blade may be employed to reduce buckling as the cutting guide is configured to hold the saw blade in place while making the necessary cuts. The use of cutting guides often require the use of longer blades, which can still introduce skiving effects. Additionally, most of the currently used cutting guides requires that the cutting guide is first secured to the bone at the desired location so that the surgery time is increased. Furthermore, the actually available cutting guide are bulky, cluttering the field of view of the surgeon and bothering the surgeon during the cutting operation.

Finally, some cutting tool uses cutting guides being monitored by means of active control systems, said control systems being part of a robotic cutting system.

This active control system may deprive the surgeon of their freedom of movement, and iterative corrections of the control system may induce some lagging, thus decreasing both the maneuverability and precision of the cutting operation. Furthermore, an active control system requires an expensive automation equipment regarding to the function of guiding the cutting blade. Also, the system described partially hides the blade, thereby reducing the operator's field of view.

In robotic surgery, one of the goals is to increase cutting accuracy and reduce cutting time, which can be difficult in cases where the saw blade is unable to initially cut at a desired location and the surgeon does not have a clear view of the saw and the bone at the same time.

The current application aims at overcome those drawbacks. <CIT> discloses a surgical cutting tool according to the prior art.

In order to overcome those drawbacks, the current invention thus relates to surgical cutting tool, such as an oscillating saw, comprising:.

When the surgical cutting tool is held by the surgeon for performing a cut (i.e., use configuration), the sliding mechanism and the sliding unit are advantageously positioned beneath the cutting blade so that the whole blade is visible to the surgeon during the cutting operation. Therefore, in the present invention the smart positioning of the sliding mechanism and the sliding unit of the cutting guide allows to avoid the undesirable skiving (e.g., deviation from an intended cut plane and/or deviation from an intended entry point) that occurs during the cutting process while gathering the whole cutting blade in full sight of the surgeon.

According to one embodiment, the abutment element is configured to be positioned below the cutting blade in use configuration.

According to one embodiment, also the blade maintaining element is configured to be positioned entirely below the cutting blade in use configuration. In this configuration, all the elements of the cutting guide positioned entirely below the cutting blade in use configuration, which provides an even more free field of view for the surgeon, all without losing precision due to the undesired skiving. Indeed, even in this configuration the blade is advantageously supported by the blade maintaining element.

According to one embodiment, the sliding mechanism is a passive mechanism. This embodiment advantageously allows to prevent the risk of lagging and the risk of electronical breakdown. Being free of any sort of complicated electronic device, the surgical cutting tool according to the present invention is light, easy to handle and does not reduce the fluidity of the cutting operation.

The surgical cutting tool according to the invention may include one or several of the following features presented in the following embodiments, taken isolated from each other or in combination which each other.

According to one embodiment, the cutting blade displays a front and a back end, the front end being the cutting end and the back end being the end connected to the casing.

According to one embodiment, the cutting guide displaying two configurations:.

wherein the cutting guide changes from the resting configuration to the active configuration when the cutting guide is activated.

According to one embodiment, when sliding mechanism is a passive mechanism, it includes at least one spring element being configured to cooperate with the sliding unit in order to enable the cutting guide to change from the active configuration to the resting configuration when the cutting guide stops being activated.

According to one embodiment, the blade maintaining element comprises a magnet aimed at cooperating by magnetization with the cutting blade.

According to one embodiment, the blade maintaining element comprises a slot aimed at receiving the cutting blade.

According to one embodiment, the blade maintaining element at being positioned under the cutting blade.

According to one embodiment, the abutment element is configured to block the cutting guide along an axis sensibly perpendicular to the sliding axis.

According to one embodiment, the abutment element displays at least one spike aimed at reversibly securing the cutting guide to an abutment body part of the patient.

According to one embodiment, the abutment element displays at least one transversal ridge aimed at reversibly securing the cutting guide to an abutment body part of the patient along the direction of the axis sensibly perpendicular to the sliding axis.

According to one embodiment, the abutment element displays a rounded shape aimed at fitting a natural curve of an abutment body part of the patient,.

According to one embodiment, the abutment element displays an ergonomic shape configured to allow a comfortable and safe positioning of the operator's hand,.

According to one embodiment, the cutting guide is integrally formed with the casing,.

According to one embodiment, the invention relates to a cutting guide aimed at being connected to a surgical cutting tool such as an oscillating saw, said tool comprising a casing enclosing a motor, said motor being connected to the cutting blade, a cutting blade aimed at cutting a patient's anatomical element according to a cutting plane. The cutting guide comprises:.

The sliding mechanism is a passive mechanism, and the sliding unit, the blade maintaining element and the abutment element remain static with regards to the patient's anatomical element when the cutting guide is activated by the pressure resulting from the cutting tool being pushed towards said patient's anatomical element.

As the cutting guide according to the present invention relies on a passive mechanism, there is no risk of lagging and no risk of any electronical breakdown. Being free of any sort of complicated electronic device, the cutting guide according to the present invention is light, easy to handle and does not reduce the fluidity of the cutting operation.

As can be seen on <FIG> and <FIG>, a surgical cutting tool <NUM> displays a general elongated shape extending along an elongation axis X, defining a cutting direction. The surgical cutting tool <NUM> comprises a casing <NUM> extending along said elongation axis X. The casing <NUM> encloses a motor (not represented) aimed at putting the surgical tool <NUM> into motion. The casing <NUM> displays a front face 12A, a back face 12B linked to each other by, according to an axis Y sensibly perpendicular to the elongation axis X, an upper face 12C, an underside face 12D and, according to a transversal axis Z, two flank sides 12E. On the example illustrated on <FIG>, <FIG>, <FIG> and <FIG>, the casing <NUM> displays a cylindrical shape of approximately <NUM> long and <NUM> wide. The surgical cutting tool <NUM> aims at being handled by an operator, in particular a surgeon, by means of a handle <NUM> connected to the casing <NUM>. In the example illustrated on <FIG>, <FIG>, <FIG> and <FIG> the handle <NUM> extends, from the underside 12D. In this case, when the surgical cutting tool <NUM> is used by the operator (i.e., in use configuration), the underside 12D is out of their field of vision.

In the current application, the terminology "sensibly" refers to the measurement error margin.

In the current application, the terminologies "front" and "back" of the various elements take are defined with regards to the cutting direction, the front being oriented positively along the cutting direction and the back being orientated negatively along the cutting direction.

The surgical tool <NUM> further comprises a cutting blade <NUM>. This cutting blade <NUM> is aimed at cutting a patient's anatomical element A, for example a bone. This cut takes place, as already mentioned in the introduction, within a cutting plane P. The cutting blade <NUM> displays two ends: a front end 16A and a back end 16B. The front end 16A is the end aimed at cutting the anatomical element A, it is the cutting end. The back end 16B is the end which is connected to the motor inside the casing <NUM> and thus connected to the casing <NUM>. In a well-known way, the cutting blade <NUM> oscillates within the plane P around a rotation axis sensibly parallel to the Y axis situated nearby the font face 12A of the casing <NUM>. The angular rotation of the cutting blade <NUM> is around <NUM> degrees. In the examples of <FIG>, <FIG>, <FIG> and <FIG>, the cutting blade is made of a bio-compatible stainless steel and is about <NUM> long.

According to the present invention, in order to prevent the cutting blade <NUM> from bending during a cutting operation, the surgical tool <NUM> displays a cutting guide <NUM>. This cutting guide <NUM> may be a separate piece that can be attached to and detached from the casing <NUM>. In the embodiment illustrated on <FIG>, the cutting guide <NUM> is attached to the surgical tool <NUM> by means of a clamping system <NUM>. The cutting guide <NUM> may also be integrally formed with, or integrated within the casing <NUM> as illustrated on <FIG>, <FIG> and <FIG>.

According to the current invention, the cutting guide <NUM> comprises:.

The sliding unit <NUM> is aimed at sliding along the casing <NUM>. The sliding unit <NUM> thus defines a sliding axis X' which, in the embodiments illustrated on <FIG>, <FIG> and <FIG> is sensibly aligned with the elongation axis X of the surgical tool <NUM>. The sliding axis X' is further sensibly parallel with the cutting plane P. The sliding unit <NUM> displays a front end 22A and a back end 22B. The back end 22B of the sliding unit <NUM> cooperates with the sliding mechanism <NUM>. More precisely, as illustrated on <FIG>, <FIG> and <FIG>, the sliding unit <NUM> moves through the sliding mechanism <NUM>.

In the embodiment illustrated on <FIG> and <FIG>, the sliding unit <NUM> comprises at least one sliding rod, in particular two sliding rods. Each sliding rod extends, parallel to the sliding axis X', along one flank side 12E of the casing <NUM>. The presence of two sliding rods leads to an increase in stability and balance during operation. In the embodiment illustrated on <FIG>, the sliding unit <NUM> comprises a single sliding rod. In this embodiment, the sliding rod displays a general T shape. This T shape allows the rod to remain compact while displaying an improved stiffness, and further prevent the sliding rod from rotating around the axis X'. The single rod extends along the underside 12D of the casing <NUM> and is thus, during operation, invisible to the operator, as can be grasped from <FIG>.

As already mentioned, the sliding unit <NUM> carries a blade maintaining element <NUM> and an abutment element <NUM>. More precisely, and as can be seen on <FIG>, <FIG> and <FIG>, the blade maintaining element <NUM> and the abutment element <NUM> are carried by the front end 22A of the sliding unit <NUM>.

The blade maintaining element <NUM> is designed to cooperate with the cutting blade <NUM> in order to maintain the cutting blade <NUM> aligned with the sliding axis X'. During operation, the cooperation between the cutting blade <NUM> and the maintaining element <NUM> leads the cutting blade <NUM> to remain aligned within the cutting plane P. More precisely, the blade maintaining element <NUM> is positioned in such a way that, when the cutting guide <NUM> and the cutting blade <NUM> are both attached to the casing <NUM>, the cutting blade <NUM> is in contact with the maintaining element <NUM>. The blade maintaining element <NUM> thus aims at aligning the cutting blade <NUM> with the sliding unit <NUM>, thus guiding the cutting blade <NUM> during the cutting operation. During operation, the forces applied on the axis Y are thus supported by the sliding unit <NUM>, preventing the blade from bending.

In the embodiments illustrated on <FIG>, <FIG> and <FIG>, the blade maintaining element <NUM> displays a rectangular shape and comprises, on its upper face, a magnet <NUM> aimed at cooperating by magnetisation with the cutting blade <NUM>. In this embodiment, the upper face (according to axis Y) of the blade maintaining element <NUM> cooperates with an underside face (according to axis Y) of the cutting blade <NUM>. More precisely, the magnet <NUM> aims at holding the cutting blade <NUM> by magnetization. In the specific case of the embodiment illustrated on <FIG>, the magnet <NUM> is situated inside a recess, preventing the cutting blade <NUM> to rub over the magnet <NUM> and its resulting abrasion. In an alternative embodiment illustrated on <FIG>, the blade maintaining element <NUM> comprises a slot <NUM> aimed at receiving the cutting blade <NUM>.

In one advantageous embodiment, in order to ease the use of the surgical cutting tool <NUM>, the blade maintaining element <NUM> is preferably positioned under (according to the Y axis) the cutting blade <NUM>. This way, the blade maintaining element <NUM> is outside the operator's field of view and does not disturb the cutting operation.

The abutment element <NUM> aims at abutting against an abutment body part of the patient. This abutment body part may or may not be the patient's anatomical element A to be cut. The abutment element <NUM> displays a front end 26A and a back end 26B. In the embodiments illustrated on <FIG>, <FIG>, the back end 26B of the abutment element <NUM> is attached to the blade maintaining element <NUM>. The abutment element <NUM> can be integrally formed with the blade maintaining element <NUM>, the two elements <NUM>, <NUM> thus being part of the same piece. In case the patient's abutment body part is a hard body part, as for example a bone, the abutment element <NUM> may display at least one spike aimed at reversibly securing the cutting guide <NUM> to it. Preferably, the front end 26A of the abutment element <NUM> comprises a series of regularly positioned spikes, as can be seen on <FIG>. In another embodiment shown on <FIG>, the abutment element <NUM> displays at least one transversal ridge extending along a Z axis, sensibly perpendicular to the elongation axis X and to the Y axis. This ridge aims at reversibly securing the cutting guide <NUM> to a hard or a soft body part of the patient along the direction of the Y axis. The front end 26A of the abutment element <NUM> may also display at least one transversal ridge, in order to block the cutting guide movements (and thus the surgical tool <NUM>) movements along the Y axis. Preferably, and as can be seen on <FIG>, the front end 26A of the abutment element <NUM> displays a series of transversal ridges. Those ridges block the cutting guide <NUM> along the Y axis and only allow a planar movement aligned with the cutting plan P. Those ridges are shaped to avoid damaging the patient's body parts. The abutment element <NUM> may have a rounded shape aimed at fitting a natural curve of said body part, as illustrated on <FIG>. The abutment element <NUM> thus offers a controlled contact interface between the cutting guide <NUM> and the patient's anatomical element A to be cut.

During operation, the cooperation of the abutment element <NUM> and the blade maintaining element <NUM> enables a huge gain of reliability and strength during the cutting operation: while the blade maintaining element <NUM> supports and guides the cutting blade <NUM> relatively to the cutting tool <NUM>, the abutment element <NUM> rests on an abutment body part and thus guides the cutting tool <NUM> relatively to the patient's body. This cooperation, thus offers a better stability and a better accuracy in the cutting operation.

In a further embodiment illustrated on <FIG>, the back end 26B of the abutment element <NUM> displays an ergonomic and easy-to-grasp shape. This allows the operator to position their free hand H, meaning the hand which is not holding the handle <NUM>, on the abutment element <NUM> in a safe and comfortable way, leading to a better haptic feeling during the cutting operation, in particular, a better feeling of any change in the anatomical element A being cut, for example, the transition from the hard cortical tissue to the softer intramedullary inner part of a bone.

As already mentioned, the sliding unit <NUM> cooperates by sliding with the sliding mechanism <NUM>. The only degree of freedom allowed between the cutting guide <NUM> and the surgical cutting tool <NUM> is therefore a translation along the sliding axis X'.

The sliding mechanism <NUM> is a passive mechanism. This means that the cutting guide <NUM> is only manually activated by the pressure applied by the operator on the patient's anatomical element A and/or the patient's abutment body part by means of the abutment element <NUM> during the cutting operation. More precisely, it means that during the cutting operation, the sliding unit <NUM>, the blade maintaining element <NUM> and the abutment element <NUM> remain static with regards to the patient's anatomical element A when the cutting guide <NUM> is activated by the pressure resulting from the surgical cutting tool <NUM> being pushed towards said patient's anatomical element A.

As can be seen on <FIG> and <FIG>, the sliding mechanism <NUM> can be, with regards to the casing <NUM>, an external mechanism or an internal mechanism. The sliding mechanism <NUM> comprises at least one hollow shaft <NUM>, each hollow shaft <NUM> opening at the front end 12A of the casing <NUM> and each hollow shaft <NUM> being configured to receive a sliding rod of the sliding unit <NUM>. In the embodiment illustrated on <FIG> and <FIG>, the sliding mechanism displays two hollow shafts <NUM>, each shaft <NUM> extending along one flank side 12E of the casing <NUM>. In the embodiment illustrated on <FIG>, the hollow shaft <NUM> extends along the downside face 12D of the casing <NUM> and is thus, during the cutting operation, invisible to the operator.

The sliding mechanism <NUM> enables the cutting guide <NUM> to display two configurations:.

When the cutting guide <NUM> is activated, meaning when the operator exerts pressure on the cutting tool <NUM> and the cutting guide <NUM> against the patient's anatomical element A and/or the patient's abutment body part by the mean of the abutment element <NUM>, the cutting guide <NUM> changes from its resting configuration to its active configuration.

As can be seen on <FIG> and <FIG>, in some embodiments, the sliding mechanism <NUM> includes at least one spring element <NUM>. The spring element <NUM> can be a mechanical spring or, alternatively, a gas spring. Each spring element <NUM> is embedded at the back end of the sliding mechanism, inside each hollow shaft <NUM> or bore <NUM>. Each spring element <NUM> is configured to cooperate with the back end of the sliding unit <NUM>, more precisely each spring element <NUM> is configured to cooperate with the back end of each sliding rod of the sliding unit <NUM>. This cooperation enables the cutting guide <NUM> to change from its active configuration into its resting configuration when the cutting guide <NUM> stops being activated.

Claim 1:
A surgical cutting tool (<NUM>), such as an oscillating saw, comprising:
- a cutting blade (<NUM>) aimed at cutting an anatomical element (A) of a patient according to a cutting plane (P),
- a casing (<NUM>) enclosing a motor, said motor being connected to said cutting blade (<NUM>), and
- a cutting guide (<NUM>) comprising:
- a sliding mechanism (<NUM>) connected to the casing (<NUM>),
- a sliding unit (<NUM>) coupled to the casing (<NUM>) by means of the sliding mechanism (<NUM>), the sliding unit (<NUM>) defining a sliding axis (X') being sensibly parallel with the cutting plane (P), and cooperates by sliding with the sliding mechanism (<NUM>), the sliding unit (<NUM>) being aimed at sliding along the casing (<NUM>),
- a blade maintaining element (<NUM>) carried by the sliding unit (<NUM>), the blade maintaining element (<NUM>) being configured to cooperate with the cutting blade (<NUM>) in order to maintain the cutting blade (<NUM>) aligned with the sliding axis (X'),
- an abutment element (<NUM>) carried by the sliding unit (<NUM>), said abutment element (<NUM>) being aimed at abutting against an abutment body part of the patient,
wherein the sliding unit (<NUM>), the blade maintaining element (<NUM>) and the abutment element (<NUM>) remain static with regards to the patient's anatomical element (A) when the cutting guide (<NUM>) is activated by the pressure resulting from the surgical cutting tool (<NUM>) being pushed towards said patient's anatomical element (A),
characterised in that
- the surgical cutting tool (<NUM>) comprises a handle (<NUM>) extending from an underside (12D) of the casing (<NUM>) and configured to be held by an operator in use configuration, and
- the sliding mechanism (<NUM>) and the sliding unit (<NUM>) are configured to be positioned below the cutting blade (<NUM>) in said use configuration.