Patent Description:
It is known that during some surgical operations it is necessary to work on teeth or bones by using a suitable cutter. Some examples of such operations include treatment of hallux valgus, dental fillings, or other mini-invasive and non-mini-invasive operations.

Reference will be made below to mini-invasive techniques that have so far required the use of specifically designed equipment, which equipment is however also used for other operations.

The so-called "mini-invasive" operations ensure as little invasiveness as possible and require a specific technique, also identified as mini-invasive or percutaneous; according to said technique, a small cutaneous incision is made, through which the surgical tools necessary for the actual operation are inserted.

In this context, surgical tools are known, such as "mini-cutters", or other instruments that may be useful or necessary from time to time, by means of which osteotomies are carried out in order to obtain correct bone realignment or to remove bone growths from incorrect areas, or caries, or the like.

Said tools are normally supported by a spindle, or handpiece, which can be manipulated, or guided, by a surgeon's hand to properly control and conduct the tool in the working area.

Said handpiece may have different shapes and, in general terms, includes a through shaft that receives motion from motor means directly connected to the handpiece; the handpiece transmits the motion to the tool while at the same time positioning it relative to itself.

For example, a handpiece may have an axial shape or may have an angle ranging from a few degrees to <NUM> degrees.

The tool is normally so shaped as to expel the osteotomy or caries products, such as humus, blood and debris, thus keeping the working area as clean as possible.

For simplicity's sake, the term osteotomy will hereafter refer to all cases wherein handpieces are or can be used.

In particular, due to the conformation of the tool, humus, blood and debris can easily flow up the rotation shaft and, at least partly, enter the handpiece, where they gather in one or more spaces. Such products may foul the handpiece and the internals thereof, and may become, if not removed, a possible source of infection.

The handpieces known in the art are normally made of stainless steel or other medical materials to ensure safe cleaning.

Although such handpieces can be cleaned externally, generally their interior, where pathogenic agents may reside, cannot be easily subjected to in-depth cleaning.

In order to clean them internally, in fact, it is necessary to disassemble the various components and carry out a complex and thorough cleaning, as well as a deep disinfection of each component, followed by proper lubrication. Such operations are necessary to minimize the permanence of bacteria, viruses or the like, which may otherwise first proliferate and then move into a patient's body during the next operation.

Handpieces are also known which are somehow prearranged for being quite easily cleaned; such units can be rather easily fully or partially disassembled for cleaning and disinfecting the interior and all components from anything that may have entered and/or accumulated therein.

However, the activities of disassembling, cleaning, sanitizing, lubricating and reassembling the components, if carried out properly, are time-consuming, and this prevents immediate reuse.

For this reason, and in order to ensure patient's safety, modern handpieces require considerable costs, adding to the supply cost, for cleaning and management, provided that in-depth cleaning is possible and easy.

For these very reasons, moreover, the handpiece must be replaced with a clean one before every operation, because cleaning cannot be done locally.

This requires the availability of some stock of clean handpieces in excess of those that are strictly necessary for the operations to be carried out.

In fact, as the handpieces are used during a working day, they must be replaced to avoid losing time. As a consequence, the necessary stock and the necessary cleaning operations cause organization problems not related to the surgery, as well as management and cleaning cost problems. Such costs and times affect each surgical operation to a non-negligible extent.

As a matter of fact, the mechanical components of the handpieces known in the art are typically made of metal, and are complex and articulated to provide the characteristics that the handpiece must have in order to be properly controllable and have a long service life, such long service life being necessary to amortize the supply and management costs, while avoiding that even minimal dirt residues might contaminate the next operation.

A need has therefore arisen for replacing the known handpieces with other handpieces that, while still being safe and ensuring reliable operation, can be considered as disposable units.

In particular, it is also one object of the invention to provide a handpiece that allows reducing the times and costs incurred for essential cleaning and reassembly, if a handpiece that can be reused only a few times is required.

It is another object of the present invention to provide a handpiece that can be reused for a small number of surgical operations.

It is another object of the present invention to provide handpieces that can be cleaned easily and quickly.

Thus, the cost of a handpiece according to the invention is very low, and surgical operations cost much less as well. Furthermore, organization is simplified and additional costs are eliminated, while still fulfilling all the needs that may arise during a surgical operation.

In order to overcome the drawbacks of the prior art and attain these and other objects and advantages, the Applicants have studied, tested and realized the present invention.

Document <CIT> describes a surgical instrument with an articulated region.

Document <CIT> describes a medical instrument for bone surgery.

The present invention is set out and characterized in the independent claim. Dependent claims set out other features of the present invention or variants of the main inventive idea.

In accordance with the above-mentioned objects, a handpiece for supporting and positioning a surgical tool according to the present invention, made of plastic material or the like, is provided which can be used only once or only a few times after having been subjected to a cleaning operation, and then disposed of or subjected to a process of regeneration or recovery of its constituent material.

In accordance with one aspect of the present invention, the plastic material that constitutes said handpiece is of the eco-compatible type and meets the requirements of biocompatibility with the human body.

In accordance with a first embodiment, all of said plastic material is advantageously comprised in a single category of eco-compatible plastic material.

Advantageously, the plastic material is recyclable and the handpiece can be regenerated, or recycled, without having to be disassembled first.

According to the invention, the handpiece may have an axial longitudinal development.

According to one variant, the handpiece may have a partial axial development and then extend at a desired angle.

According to the invention, the handpiece comprises an external body and motion transmission means disposed inside said external body; said transmission means being configured to receive motion from a motor member and transmit it directly to the tool.

According to a further variant, in the case of a handpiece with an angled output, motion transmission means in angular form are provided, said means being gears or gearing means or rotating hinges or angled hinges, or other means commonly known for transmitting angular motion between two mutually angled shafts.

According to one variant of the invention, the external body and the motion transmission means, as well as spring means, bushings, abutments, etc., are all advantageously made of plastic material.

According to a further variant, the tool is advantageously of the type that can be so applied that it can be disconnected from the handpiece body as needed.

According to a further variant, the handpiece is made as two pieces, wherein the rear part is used for receiving motion and for gripping the handpiece with the hand, while the front part has an extension that may be either axial or angled by a desired value.

This makes it possible to have a standard main body and a specialized part as required from time to time.

According to the invention, the handpiece can be replaced, even during the surgical operation, and directly or indirectly applied to the means supplying rotation thereto, i.e. a direct or remote motor member.

It is within the principles of the invention that, if the connections between the handpiece and the motor member are not standardized ones, the handpiece may be fit for different connections, or that mutual and intermediate connection means, e.g. adapters, can be applied thereto and replaced.

According to the invention, said motion transmission means comprise a transmission shaft, or possibly also gearing or hinging means o other angular motion transmission means having a first end configured to be connected to the motor member and a second end configured to be connected to the tool.

According to one variant, the transmission means are associated with elastic means, e.g. a spring, which ensure a proper and stable axial connection of the same.

The handpiece further comprises means for supporting and positioning the transmission shaft, which allow the latter to rotate correctly about a longitudinal axis.

According to the invention, the supporting and positioning means are made of plastic material; they act as a bearing, a bushing, a thrust bearing or a spring, and perform a containment or locking function.

According to one variant of the invention, said supporting and positioning means comprise also at least one internal body at least partly disposed inside the external body and configured to contain and position the transmission shaft or a part thereof.

According to one variant, the body is made up of external bodies and one or more internal bodies.

According to one variant, the external body is made as one piece.

According to one variant, the external body and/or the internal body is made as two bodies which can be coupled and made integral with each other through fixed connection means.

According to one variant of the invention, the transmission shaft is divided into two or more components including, possibly in an intermediate position, angular transmission means, and comprises a first portion and at least a second portion separated and in reciprocal torsional engagement which cooperate to transmit motion while allowing for reciprocal axial sliding.

As aforementioned, the transmission shaft may be composed of one or more parts and may include the tool, or the tool can be replaced during the operation. If the tool can be replaced during the operation, both the tool and the transmission shaft have means for mutual connection, engagement and positioning and for rotary motion transmission; one example may be a flat, polygonal, etc. seat having (at least temporary) axial retaining means.

According to one variant, the handpiece has an ergonomical shape.

According to the invention, the handpiece is provided with means for centering and positioning it relative to, and possibly for establishing an axial connection with, the motor member or the terminal part thereof.

According to the invention, in order to provide engagement with the motor member, the axial position of the transmission shaft is held by spring means that ensure the proper connection thereof, which spring means are, advantageously but not necessarily, made of plastic material.

According to one variant, the external part of the handpiece includes means for positioning the operator's hand and improving the grip thereof.

According to one possible variant, the external body is internally provided with one or more seats having different diameters, with which the supporting and positioning means, such as bearings, bushings, thrust bearings or springs, can be associated to ensure proper and controlled axial positioning of the transmission shaft, said supporting and positioning means being made of plastic material, which material is advantageously specifically suited to the function to be performed.

According to one variant, at least some of the various parts of the handpiece can be connected by mutual fastening.

According to one variant, they can be connected by means of suitable rings or clips or slides.

According to a further variant, they can be connected by mutual screwing.

According to a further variant, they can be connected by gluing.

According to one variant, the motor shaft may be of the type that can be inserted into the external body from the front.

According to one variant, the motor shaft may be of the type that can be inserted into the external body from the rear.

In accordance with a further aspect, the invention concerns a surgical instrument.

Preferably, the surgical instrument comprises a handpiece for supporting and positioning a surgical tool.

Preferably, the surgical instrument comprises a motor member.

Preferably, the motor member is coupled to said handpiece for transmitting a rotary motion to the tool supported by said handpiece.

Preferably, the surgical instrument comprises a fastening member.

Preferably, the fastening member is configured to temporarily fasten a protection element to either said motor member or said handpiece in order to cover said motor member at least partially.

Preferably, said fastening member is cup-shaped.

Preferably, said fastening member has an opening facing towards said handpiece.

Preferably, said fastening member has a through hole opposite said opening.

Preferably, a radially internal surface of said protection element is coupled to a radially external surface of said fastening member.

Preferably, the coupling between the radially internal surface of the protection element and the radially external surface of the fastening member is effected by gluing.

Preferably, the coupling between the radially internal surface of the protection element and the radially external surface of the fastening member is effected by slot-and-hook coupling.

These and other aspects, features and advantages of the present invention will become apparent in light of the following description of some embodiments thereof, provided by way of non-limiting example with reference to the annexed drawings, wherein:.

It must be pointed out that the expressions and terms used in the present description, as well as the annexed drawings described herein, have the sole function of properly explaining and illustrating the present invention by means of some examples of embodiment, thus having only an explanatory and non-limiting function, since the protection scope of the invention is defined in the claims.

For a better understanding, the same reference numerals have been used, wherever possible, for identifying identical items common to different figures.

It remains understood that elements and features of one embodiment may be conveniently combined or incorporated in other embodiments without requiring any further clarification.

With reference to the annexed drawings, a spindle, or handpiece, <NUM> according to the present invention is configured for supporting and positioning a surgical tool <NUM>, for the purpose of allowing an operator to guide the latter during surgical operations.

The figures annexed hereto for illustrative purposes show some examples of various implementations of the handpiece <NUM> according to the present invention, so as to remark the breadth of possible geometric solutions conveyed by the inventive idea.

In the annexed drawings a handpiece <NUM> is shown which, according to the present invention, implements only a small part of all the possible geometric formulations of the inventive idea.

It must be pointed out that the features presented in the various illustrative drawings may be variedly associated with one another to create further embodiments, being it apparent that the solutions shown herein are merely illustrative and non-limiting ones.

The surgical tool <NUM> associated with the handpiece <NUM> is adapted to remove biological material from a patient's bone portion. For example, the tool <NUM> may be a so-called mini-cutter.

In particular, the tool <NUM> is configured to rotate about an axis of rotation X1.

The axis of rotation X1 may be in axis with a longitudinal axis X for motion input of the handpiece <NUM> (<FIG>), or may be arranged at a predetermined angle, e.g. up to <NUM>°, relative to said longitudinal axis X (<FIG>).

According to one aspect of the present invention, every component of the handpiece <NUM> is made of plastic material, preferably eco-compatible and, advantageously, biocompatible with the human body.

Except for the tool <NUM>, all parts of the handpiece <NUM> according to the present invention can be obtained from recyclable plastic.

In some cases, e.g. for cleaning operations, also the tool <NUM>, or part thereof <NUM>, can be made of (reinforced) plastic material.

It is understood that the inventive idea also includes the case wherein, apart from the tool <NUM>, the handpiece comprises some metal components that can be easily removed while the rest of the handpiece can be recycled.

The handpiece <NUM> comprises an elongate external body <NUM>, suitably shaped internally and configured to be held and handled by an operator.

The external body <NUM> has a front end 16a from which a front portion 11a extends which belongs to the tool <NUM>.

The external body <NUM> has a rear end 16b having a housing <NUM> configured to cooperate with a motor member <NUM> or with a suitable intermediate adapter.

In particular, the motor member <NUM> has a motor shaft <NUM> and also a suitable centering extension <NUM> that cooperates with the housing <NUM> to connect the motor shaft <NUM> axially to the handpiece <NUM>.

Advantageously, the connection between the motor shaft <NUM> and the handpiece <NUM> preserves the sterility of the assembly.

Advantageously, the profile of the external body <NUM> from the rear end 16b to the front end 16a is such as to ensure an easy and steady grip while not hindering sight.

The external body <NUM> may have, at the rear, a fastening member <NUM>, suitable for fastening temporary covering means, e.g. a replaceable cover or protection, on at least the motor member <NUM> to prevent it from getting fouled.

Some examples of embodiment of the fastening member <NUM> will be described below with reference to <FIG>.

The external body <NUM> is either made as one piece or composed of two or more elements. When two or more elements are used, the latter may be made mutually integral by gluing, snap-type fastening means, forks, pins, or the like.

By way of example, as will be made clearer later in this description:.

The external body <NUM> may have, on its outer surface, seats <NUM> for positioning the operator's hand, and may possibly have a surface adapted to improve the grip of the operator's hand.

The handpiece <NUM> further comprises motion transmission means <NUM> disposed inside the external body <NUM> and configured to receive motion from the motor shaft <NUM> and transmit it to the tool <NUM>. The motion transmission means <NUM> comprise, for example, a transmission shaft <NUM>.

The motion transmission means <NUM> are supported and held in position by supporting and positioning means <NUM>.

The supporting and positioning means <NUM> may perform the function of bearings, or bushings, or thrust bearings, to ensure a correct axial positioning of the motion transmission means <NUM> with respect to the external body <NUM>.

In particular, the transmission shaft <NUM> has a first end, or front end, 17a.

The first end 17a of the transmission shaft <NUM> cooperates, in particular through its rear portion 11b, with the tool <NUM> in order to transfer to the latter the rotary motion and ensure the required axial positioning thereof.

In particular, the transmission shaft <NUM> has a second end, or rear end, 17b.

The second end 17b of the transmission shaft <NUM> cooperates with the motor shaft <NUM>, from which it receives the motion.

The transmission shaft <NUM> may be completely hollow in the axial direction, or it may be hollow only partially, or it may comprise a number of hollow, half-hollow and solid parts.

The supporting and positioning means <NUM> may be retained in seats directly formed on the external body <NUM>, as in the embodiment shown in <FIG>, or on special auxiliary bodies.

As an alternative or in addition, the supporting and positioning means <NUM> comprise an internal body <NUM> disposed inside the external body <NUM>, whereon one or more seats having different diameters are formed.

The internal body <NUM> is associated with the external body <NUM>; the external body <NUM> correctly and firmly holds said internal body <NUM> in position after the assembly.

The type of connection between the external body <NUM> and the internal body <NUM> may be either fixed or disassemblable.

In a first embodiment thereof, the internal body <NUM> is made as one piece (<FIG> and <FIG>).

According to one variant, the internal body <NUM> is obtained from two half-shells 116a and 116b; such half-shells 116a, 116b are coupled together along respective longitudinal profiles in order to contain and properly position the motion transmission means <NUM> (<FIG>).

For example, in the embodiment of <FIG> the internal body <NUM> is obtained from two axial half-shells 116a, 116b (i.e. substantially separable along a plane in which the longitudinal axis X lies) that are made integral with each other and correctly positioned by the external body <NUM>.

As an alternative or in addition, the two half-shells 116a, 116b are provided with mutual positioning and connecting means.

According to some embodiments, the mutual positioning and connecting means may be slides, hooks, screws, pins, etc., or may include a connection insert.

In the embodiments depicted in <FIG>, the transmission shaft <NUM> is made as one piece and has an abutment disk <NUM> disposed between its two ends 17a, 17b. In this case, the supporting and positioning means <NUM> comprise a positioning spring <NUM> that cooperates with the abutment disk <NUM>. This results in the transmission shaft <NUM> being coupled to the motor shaft <NUM> and remaining in the correct position.

Preferably, the positioning spring <NUM> is positioned in the radially internal cavity of the external body <NUM>.

In particular, the positioning spring <NUM> is separated from the internal body <NUM>, in the axial direction, by the abutment disk <NUM>. In other words, the positioning spring <NUM> and the internal body <NUM> are in abutment with the abutment disk <NUM> on axially opposite sides.

Alternatively, as in the embodiment illustrated in <FIG>, the transmission shaft <NUM> comprises a first shaft, or upper shaft, <NUM> and a second shaft, or lower shaft, <NUM>.

Preferably, the first shaft <NUM> and the second shaft <NUM> are subject to means that define a predefined and controlled axial displacement of one or both of them.

Preferably, said means that define the mutual axial displacement are obtained in a portion of the transmission shaft <NUM>.

Preferably, the means that define the at least partially predefined axial displacement of the upper shaft <NUM> and lower shaft <NUM> are obtained in the body of the transmission shaft <NUM> or, at least partly, in the internal body <NUM> and/or in the external body <NUM> of the handpiece <NUM>.

In addition, the lower shaft <NUM> has a sliding seat <NUM> in which a part of the upper shaft <NUM> is contained and allowed to slide axially.

In this case, the upper shaft <NUM> has axial sliding means that prevent it from rotating relative to the lower shaft <NUM> and that cooperate with the sliding seat <NUM>. In this case, the positioning spring <NUM> is disposed in the sliding seat <NUM>, being thus interposed between the lower shaft <NUM> and the upper shaft <NUM>.

Advantageously, the positioning spring <NUM> is also made of plastic material and may have any shape; for example, the positioning spring <NUM> may have a tubular shape and be made of elastic material.

The lower shaft <NUM>, which constitutes, together with the upper shaft <NUM>, the transmission shaft <NUM>, has a positioning ring or abutment crown <NUM>. Such positioning ring or abutment crown <NUM> is preferably disposed in a portion of the lower shaft <NUM> that is proximal to the connection with the motor shaft <NUM>, i.e. located at the rear end 16b of the external body <NUM>.

The supporting and positioning means <NUM> may further comprise a plastic bearing <NUM> whereon the abutment crown <NUM> can abut, e.g. as shown in <FIG>.

According to one variant, the upper shaft <NUM> of the transmission shaft <NUM>, which acts upon the tool <NUM>, may cooperate with a fixed annular support disposed in the external body <NUM> of the handpiece <NUM>. Such fixed annular support stabilizes the axial position of the tool <NUM> relative to the handpiece <NUM> and allows it to rotate without difficulty.

In some embodiments, e.g. as shown in <FIG>, the tool <NUM> has a circumferential expansion <NUM> projecting in a radially external direction; at the front end 16a there is a stabilizing and gripping guide, or bushing, <NUM> that receives the circumferential expansion <NUM> of the tool <NUM>.

Such stabilizing portion may be a bushing <NUM>, also made of plastic material, configured to withstand lateral thrusts relative to the longitudinal axis X, reducing as a result the stress on the transmission shaft <NUM>.

According to one variant of the invention, illustrated by way of example in <FIG> and in <FIG>, the bushing <NUM> is housed in a cover <NUM> that is correctly anchored axially to the external body <NUM>.

Said cover <NUM> may include a capsule <NUM> that encloses the front portion 16a of the external body <NUM> to stop the dirt coming from the operation.

The cover <NUM> can be replaced, together with the tool <NUM>, even while the operation is under way; the various components, e.g. the part providing angular motion, may be replaced and associated with the handpiece body in different manners according to particular technical solutions and requirements.

In <FIG> and <FIG> the cover <NUM> is obtained from two half-shells 13a, 13b held in position relative to each other, and also relative to the handpiece <NUM>, by the capsule <NUM>.

According to some embodiments described herein, the handpiece <NUM> may have either a linear profile (<FIG>) or a non-linear profile (<FIG>).

<FIG> illustrates, by way of example, a handpiece <NUM> according to the invention wherein the tool <NUM> lies at an angle relative to the axis of rotation of the motor shaft <NUM> (longitudinal axis X).

<FIG> shows a handpiece <NUM> whose terminal part, which carries the tool <NUM>, is angled by about <NUM>° relative to the longitudinal axis X.

As aforementioned, the simplified examples shown in <FIG> are only meant to suggest the wide range of application of the inventive idea. Still with reference to the simplified examples of <FIG>, the part with the tool <NUM> that is angled relative to the axis of the body gripped by the operator's hand may either be made as one piece with said body handled by the operator or be associable therewith.

The handpiece <NUM> may be constituted by a first body connectable to the motor member <NUM> and, for example, suitable for being properly gripped by the operator, and a second body that may have a linear or angled profile. Such two bodies can be associated with each other to form the required handpiece <NUM> according to needs arising from time to time.

In the possible solutions provided by the invention, the two mutually facing bodies may be equipped with mutual positioning and connecting means which may consist of slides, hooks, bayonets, pins, threads, or means cooperating with a connection insert or snap-type positioning means, or interference fitting means.

<FIG> show an example of embodiment that is merely illustrative, both because that type of handpiece <NUM> may have different angles and because motion transmission may occur through tapered gears R1, R2, a differential gear, angular joints, flexible or spiral shafts made of plastic material, cardan joints, elastic connection joints, etc..

In the case of the angled handpiece <NUM> (<FIG>), it may be made up of two bodies coupled together by screwing means or by gluing, wherein both bodies can be replaced with other bodies having different characteristics.

In this variant, a spring <NUM> performs the function of keeping the gears R1 and R2, or any other angular transmission members as previously mentioned by way of example, in mutual rotational connection.

Still by way of example, the terminal part of the handpiece <NUM> may be obtained from two bodies <NUM> and <NUM>, which can then be made firmly integral with each other, e.g. by means of glue or a ring 113a.

As a possible exemplary variant for properly controlling the gears R1 and R2 transmitting the angular motion, a cover <NUM> may be provided, which may be either removable or firmly attached or locked.

In the variant of <FIG>, instead, in the region where the axis of rotation X1 crosses the longitudinal axis X there are two selectively removable plugs T1 and T2 which allow access to the inside of the handpiece <NUM> for working on the gears R1, R2 and/or on the motion transmission means <NUM> associated therewith.

According to a further variant of the invention, either the body connected to the motor member <NUM> or the applicable specialized one may be of a standard type if it is absolutely certain that no humus can enter, which will depend on their physical conformation and on the possibility or not of receiving the humus of the operation.

According to one variant, in some cases the springs <NUM>, <NUM>, if present, are made of metal, but according to the invention they are preferably made of plastic material.

<FIG> show a surgical instrument, designated as a whole by reference numeral <NUM>, to which the above-described handpiece <NUM> may belong. It should be noted, however, that the surgical instrument <NUM> may comprise a handpiece which is different from those described above with reference to <FIG>.

In addition to the handpiece <NUM>, the surgical instrument <NUM> comprises a motor member <NUM>.

The handpiece <NUM> may be of a replaceable type.

The handpiece <NUM> is adapted to be associated with the motor member <NUM>.

The handpiece <NUM> has a grip zone <NUM> (<FIG>) suitable to ensure proper grip by the user; in one embodiment, the grip zone <NUM> has a rear abutment <NUM> for the operator's hand.

The grip zone <NUM> may, for example, be made like the external body <NUM> described with reference to <FIG>.

The handpiece <NUM> is configured to be connected to a tool <NUM>.

In particular, the handpiece <NUM> is configured to support the tool <NUM> at its front part. Such front part may be the front end 16a of the external body <NUM>.

The tool <NUM> may be of a replaceable type.

The tool <NUM> comprises a head or front portion 11a, e.g. a cutting element suitable for a specific purpose ("mini-cutter"), and a stem <NUM> for fastening it to the handpiece <NUM>.

The rear part of the handpiece <NUM> may include a connecting body <NUM> configured to be connected to the motor member <NUM>.

The connecting body <NUM> may correspond, for example, to the rear end 16b of the external body <NUM>.

As mentioned above, the surgical instrument <NUM> comprises a fastening member <NUM> for fastening a protection element <NUM>. The protection element <NUM> is configured to cover, at least partially, the motor member <NUM> and possibly a cable (not shown) upstream of the motor member <NUM>.

The fastening member <NUM> is configured to hold in position (preferably in a removable manner) the protection element <NUM> by utilizing one or more of interference, friction, elastic force, glue, adhesive material, etc..

In some embodiments, the fastening member <NUM> may comprise an annular element that surrounds the protection element <NUM> and at least one of the connecting body <NUM> of the handpiece <NUM> and the front part of the motor member <NUM>.

In some embodiments, the fastening member <NUM> may comprise a fork-shaped element that elastically clamps the front terminal part of the protection element <NUM> on either the connecting body <NUM> of the handpiece <NUM> or the front part of the motor member <NUM>.

In some embodiments, the fastening member may comprise elastic means that permit inserting the handpiece <NUM> or the motor member <NUM> and will then stay anchored by elasticity.

In some embodiments, the fastening member <NUM> may comprise means which require overlapping the ends of the front part of the protection element <NUM> and holding them in position through means for temporary, mutual and stable connection.

The protection element <NUM> may be made of any suitable material, such as, for example, a plastic or paper sheet or the like, nonwoven fabric, a tubular plastic or paper element, or the like. In some embodiments, the protection element <NUM> may be made from light cloth.

Preferably, the fastening member <NUM> can be applied easily and works by axial or orthogonal interference (elastic fork or elastic means or temporary retaining means), and can also be easily cleaned, if necessary.

In <FIG>, the fastening member <NUM> is shaped as a cup facing towards the front part of the handpiece <NUM>.

The cup-shaped fastening member <NUM> can be fitted onto the connecting body <NUM>, which may correspond to the rear end 16b of the external body <NUM>.

In some embodiments, the fastening member <NUM> has, on a radially external surface thereof, first hooking portions consisting of hooks or slots; the protection element <NUM> is provided, in the part thereof to be anchored to the fastening member <NUM>, with second hooking portions, consisting of slots or hooks. Thus, the constraint between the fastening member <NUM> and the protection element <NUM> is one of the slot-and-hook type. For example, tapes commercially available under the name of Velcro® may be used. In addition or as an alternative, the constraint between the fastening member <NUM> and the protection element <NUM> may be attained by using an adhesive material or a glue. The fastening member <NUM> may be constrained to the remaining part of the handpiece (e.g. the external body <NUM>) by interference, gluing or any other suitable mechanical coupling. Preferably, the fastening member <NUM> is cup-shaped, with the opening facing towards the front part of the handpiece <NUM>. Preferably, the fastening member <NUM> has a through hole, on the side opposite the opening, through which the output shaft of the motor member <NUM> (or the adapter connected thereto) can pass.

In some embodiments, the fastening member <NUM> comprises an elastic element <NUM> configured to cooperate with either the handpiece <NUM> or the motor member <NUM> to fasten the protection element <NUM> by interference. In some embodiments, the elastic element <NUM> located within a fold of the protection element <NUM> may be replaced with a fork that clamps the protection element <NUM> from the outside.

Instead of the elastic element <NUM>, a thread may be provided which has to be tied or stretched in order to clasp the final part of the cover onto the handpiece <NUM> or the motor member <NUM>.

In some embodiments, the fastening member <NUM> may comprise binding means, e.g. consisting of an eyelet <NUM> (<FIG>) adapted to contain a cord or an elastic element <NUM> extending annularly, which can be fastened by means of a knot or mechanical means to the handpiece <NUM>, whether in a cavity of the motor member <NUM> or in a suitable seat equipped with retaining means.

In one embodiment, the fastening means <NUM> may comprise a circumferential seat <NUM> (<FIG>) or <NUM> (<FIG>) respectively formed at the front terminal part of the motor member <NUM> or on the connecting body <NUM> (<FIG>) of the handpiece <NUM>, so as to make it easier to firmly fasten the cord or elastic element <NUM>.

The protection element <NUM> thus covers the motor member <NUM>, and possibly also the cable upstream of the motor member <NUM>.

When the surgical operation is complete, the protection element <NUM> is removed and, whenever appropriate, disposed of; the fastening member <NUM> can be easily and quickly cleaned and, if necessary, reused. Anyway, also the fastening member <NUM> may be discarded, if necessary and appropriate.

In the present invention, in addition to facilitating the application of the protection element <NUM>, a firm and reliable (and, in some embodiments, removable) connection is maintained between the protection element <NUM> and the handpiece <NUM>.

It should be noted that the fastening member <NUM> can also be used with handpieces having a structure different from the one shown in <FIG>.

The invention can thus relate to a surgical instrument <NUM> comprising a motor member <NUM> and a handpiece <NUM>; the handpiece <NUM> is adapted to be associated with said motor member <NUM>; the handpiece <NUM> is configured to support a tool <NUM>, which is rotatably driven by said motor member; the surgical instrument <NUM> comprises a fastening member <NUM> for fastening, at least temporarily, a protection element <NUM> to either said motor member <NUM> or said handpiece <NUM> in order to cover said motor member <NUM> at least partially.

Preferably, said protection element <NUM> has a tubular shape, or is configured to form a tubular structure.

Preferably, said fastening member <NUM> provides a removable constraint between the protection element <NUM> and at least one of the motor member <NUM> and the handpiece <NUM>.

Preferably, said fastening member <NUM> is cup-shaped or disk-shaped.

Preferably, said fastening member <NUM> comprises elastic means <NUM> configured to cooperate with either the handpiece <NUM> or said motor member <NUM>.

Preferably, said fastening member <NUM> is configured to fasten the protection element <NUM> by interference with said handpiece <NUM>.

Preferably, said fastening member <NUM> comprises a circumferential seat <NUM>, <NUM> and binding means <NUM>, <NUM> adapted to cooperate with said circumferential seat.

Preferably, said circumferential seat <NUM> is formed on said motor member <NUM>.

Claim 1:
Handpiece (<NUM>), be it linear or angular, for supporting and positioning a surgical tool (<NUM>), said handpiece (<NUM>) being made of plastic material,
wherein said handpiece (<NUM>) comprises at least one external body (<NUM>) and motion transmission means (<NUM>) disposed inside said external body (<NUM>) and configured to receive motion from a motor member (<NUM>) and transmit it directly to said tool (<NUM>), said external body (<NUM>) and said motion transmission means (<NUM>) being made of plastic material,
wherein said motion transmission means (<NUM>) comprise a transmission shaft (<NUM>) having a first end (17a) configured to be connected to a motor member (<NUM>) and a second end (17b) configured to be connected to said tool (<NUM>), wherein said handpiece (<NUM>) further comprises means (<NUM>) for supporting and positioning said transmission shaft (<NUM>) and for allowing the latter to rotate about a longitudinal axis (X),
wherein said transmission shaft (<NUM>) comprises a first shaft (<NUM>) and a second shaft (<NUM>) separated and in reciprocal torsional engagement, which cooperate to transmit motion while allowing for reciprocal axial sliding,
characterized in that
said supporting and positioning means (<NUM>) comprise spring means (<NUM>),
wherein said spring means (<NUM>) are interposed between said first shaft (<NUM>) and said second shaft (<NUM>) of said transmission shaft (<NUM>).