Patent Description:
The prosthetic device as above is particularly suitable for applications in patients with non-extensive joint pathologies, for example in the case of osteoarthrosis/osteoarthritis, condylar resorption, benign neoplasms, or in the case where previous surgeries have failed.

This solution can also be adopted as a first surgery in a large number of patients, where the traditional path would involve other attempts at functional arthroplasty, normally destined to fail.

It is known that the reconstruction of the temporomandibular joint is a problem due to the complex role it plays inside the stomatognathic system.

It plays an essential role in chewing, in speech, in supporting respiratory exchanges and in swallowing, and is a secondary growth center for the jaw during pre-puberty. Furthermore, the temporomandibular joint is subjected to repeated loading/unloading cycles more than any other joint in the body.

Given the complexity of the anatomy and biomechanics of said joint, surgery to solve problems and related pathologies is complex and currently very invasive.

The temporomandibular joint articulates the mandibular bone with the temporal bone, in particular it connects the mandibular condyle with the glenoid fossa of the temporal bone.

Prosthetic devices for the temporomandibular joint therefore comprise two components: a condyle prosthesis and a glenoid fossa prosthesis respectively associated, during use, with the mandibular condyle and the glenoid fossa of the temporal bone. Both components are made according to the specific needs of the patient and his/her anatomical morphology.

Known prosthetic devices for the temporomandibular joint are disclosed for example in <CIT>, disclosing a prosthetic device for temporomandibular joint according to the preamble of claim <NUM>, and <CIT>, disclosing a guide device for preparing an anchoring seating for a prosthetic device, according to the preamble of claim <NUM>.

Before they are applied, it is necessary to perform osteotomies to prepare the condyle and the glenoid fossa to accommodate the respective prostheses. For this purpose, guide devices can be provided able to facilitate the operation of bone resection performed by the surgeon. Furthermore, it is necessary to use traditional surgical burrs that cause damage, even very extensive, to the affected bone tissues and those surrounding them.

The prosthetic devices currently used are very bulky and require a very large installation space between the mandibular branch and the base of the skull, which is necessary to be able to insert the fossa prosthesis and the condyle prosthesis. Because of this, often the osteotomy of the condyle, and if necessary also of the glenoid fossa, must necessarily be very large and invasive.

This limits the indications for the implantation of the joint prosthesis only to very severe cases.

The sizes of current prostheses also make the surgical procedure very invasive, which provides a pre-auricular incision, for the insertion of the glenoid fossa prosthesis, and a retro-submandibular incision, for the insertion of the branch/condyle prosthesis.

The invasiveness of current prostheses and the surgical procedure for their installation lead to long hospitalization times and possible complications for the patient.

There is therefore a need to perfect a prosthetic device for application to the temporomandibular joint and corresponding prosthetic assembly that can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide a prosthetic device for temporomandibular joint the implantation of which requires a limited osteotomy of the condyle and possibly of the glenoid fossa.

Another purpose of the present invention is to provide a prosthetic device for temporomandibular joint that allows to extend the surgical indications, and therefore applicability, to a greater number of patients compared with the use of traditional prostheses.

Another purpose of the present invention is to provide a prosthetic device for temporomandibular joint that consists of a limited number of components so as to simplify and speed up its installation.

Another purpose of the present invention is to provide a prosthetic assembly for temporomandibular joint that is advantageously customized/individualized and patient-specific, and that allows to simplify and at the same time make the corresponding surgical technique less invasive.

In accordance with the above purposes, a prosthetic device for temporomandibular joint, which overcomes the limits of the state of the art and eliminates the defects present therein, comprises a first prosthetic component, able to be associated with a mandibular condyle of a patient, and a coordinated second prosthetic component, able to be associated with a respective glenoid fossa of the patient.

The first prosthetic component is configured to cooperate with the second prosthetic component to define the temporomandibular joint and comprises a convex portion, configured to cooperate with the second prosthetic component to define the temporomandibular joint.

According to one aspect of the present invention, the first prosthetic component comprises at least one anchoring element projecting from, and attached at least to, the concave portion as above, since the anchoring element is contained in the concave portion and has a main extension along a latero-medial axis. The anchoring element is configured to be inserted into a mating anchoring seating present, or provided, on the mandibular condyle as above. Furthermore, the coupling seating is at least partly open along the latero-medial axis.

In this way, the first prosthetic component can be easily inserted in a direction parallel to the latero-medial axis as above, allowing to limit the removal of bone material from the patient to a minimum, and at the same time allows to greatly simplify the surgical practice. In addition, the minimal invasiveness of the surgical approach and of the resection of the condyle allows to extend the surgical indications and therefore a considerably greater applicability compared with the use of traditional prostheses.

In some embodiments, the first prosthetic component comprises a concave portion, defining a coupling seating having a shape mating with the shape of the mandibular condyle. The concave portion is therefore configured to cooperate with the second prosthetic component to define the temporomandibular joint. The convex portion as above is opposite the concave portion.

In accordance with some embodiments, a guide device is provided to prepare an anchoring seating for the prosthetic device as above, in particular to position the first prosthetic component.

The guide device comprises a central body able to be positioned against at least the upper lateral part of a mandibular condylar branch, and a guide wall associated at the upper part with the central body and having the profile of the osteotomy to be performed on the condyle.

According to a characteristic aspect of the present invention, the guide device has a groove which extends vertically from the guide wall toward the central body. Furthermore, the groove is open at the upper part and is through in a direction parallel to the latero-medial axis.

Some embodiments of the present invention comprise a prosthetic assembly, advantageously customized and patient-specific, provided with the prosthetic device and the corresponding guide device as above.

We will now refer in detail to the possible embodiments of the invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, one or more characteristics shown or described insomuch as they are part of one embodiment can be varied or adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall include all such modifications and variants.

Some embodiments described here concern a prosthetic device <NUM> for temporomandibular joint (<FIG>) and a guide device <NUM> (<FIG>) required to prepare a specific anchoring seating <NUM> (<FIG>) for the prosthetic device <NUM>, as will be described in more detail below. Other embodiments also include a prosthetic assembly, advantageously customized/individualized and patient-specific, which comprises the prosthetic device <NUM> and the guide device <NUM>.

Here and hereafter, the terms proximal, distal, anterior, posterior, medial, lateral are defined by their standard use for a person of skill in the art to indicate a particular aspect or orientation of a bone, an anatomical part, a prosthetic device and its components, or other elements according to the relative disposition of the natural anatomy of the human and/or animal body, or directional terms of reference with respect thereto.

With particular reference to <FIG>, the temporomandibular joint articulates the mandibular bone <NUM> with the temporal bone <NUM>, in particular it connects a mandibular condyle (<FIG>), hereafter condyle, <NUM> with a respective glenoid fossa of the temporal bone <NUM>, hereafter fossa.

The prosthetic device <NUM> therefore comprises a first prosthetic component <NUM>, able to be associated with a condyle <NUM> of a patient, and a coordinated second prosthetic component <NUM>, able to be associated with a respective fossa of the patient. In particular, the condyle <NUM> is suitably shaped to house the first prosthetic component <NUM>, as will be described in more detail below.

The first prosthetic component <NUM> comprises a concave portion <NUM>, defining a coupling seating <NUM> having a shape mating with the shape of the previously shaped condyle <NUM>.

The first component <NUM> comprises a convex portion <NUM>, opposite the concave portion <NUM> and configured to couple with the second prosthetic component <NUM> to define the temporomandibular joint.

The first prosthetic component <NUM> is provided with at least one anchoring element <NUM> projecting from, and attached at least to, the concave portion <NUM>. The anchoring element <NUM> has an overall size such as to be substantially contained inside the concave portion <NUM>.

The anchoring element <NUM> has a main extension along a latero-medial axis X. In particular, the term latero-medial here and hereafter is intended to indicate a direction that goes from a lateral zone toward a zone located in the proximity of the median plane of the patient's body.

The anchoring element <NUM> is configured to be inserted in a mating anchoring seating <NUM> (<FIG>) made on the condyle <NUM> of the patient which is shaped following the profile of the guide device <NUM> which will be described below.

The coupling seating <NUM> is at least partly open along the latero-medial axis X so as to allow, in one possible application, the coupling of the first prosthetic component <NUM> with the condyle <NUM> in a direction parallel to the latero-medial axis, which runs from the outside to the inside (<FIG>, <FIG>). In the embodiment described here, the coupling seating <NUM> has a shape substantially mating with the articulating upper portion of the condyle <NUM>.

The particular geometry of the prosthetic device <NUM> and in particular of the first prosthetic component <NUM> provided with the anchoring element <NUM> with latero-medial insertion allows to limit the removal of bone material from the patient to a minimum, and at the same time allows to greatly simplify the surgical practice which becomes less invasive thanks to the need to only create one access route, with a pre-aural incision.

According to some embodiments described here, with particular reference to <FIG>, <FIG>, the first prosthetic component <NUM> also comprises an external lateral portion <NUM> configured to couple laterally with the condyle <NUM>. The external lateral portion <NUM> has an extension such as to allow a lateral abutment during the positioning of the first prosthetic component <NUM> along the latero-medial axis X, and to allow a stabilization thereof.

The first prosthetic component <NUM> can be configured as a condyle prosthesis configured to at least partly cover the condyle <NUM> of the patient. This first prosthetic component <NUM> is conceived as a covering prosthesis with the purpose of preserving the original bone portion of the condyle <NUM> as much as possible. Favorably, this condylar prosthesis can be used in the case of non-extensive pathologies, which in fact are those with the greatest incidence.

In particular, the first prosthetic component <NUM> is configured to cover the lateral surface of the condyle <NUM>, the upper surface - the one that normally articulates with the fossa - and possibly also the posterior and anterior surfaces. Obviously, given the mode of insertion of the first prosthetic component <NUM>, that is, in a direction parallel to the latero-medial axis X, it is not provided to cover the medial portion of the condyle <NUM> (<FIG>).

With particular reference to <FIG>, the first prosthetic component <NUM> comprises a shell <NUM> having an upper wall <NUM> and an external lateral wall <NUM> disposed inclined with respect to the upper wall <NUM>. The inclination of the external lateral wall <NUM> is essentially given by the anatomy of the mandibular branch <NUM> of the patient. In the example embodiment described here, this inclination is about <NUM>°, or slightly smaller.

The upper wall <NUM> has a shape such as to define, at the bottom, the concave portion <NUM> and, at the upper part, the convex portion <NUM> (<FIG> and <FIG>).

The upper wall <NUM> is configured to at least partly cover the condyle leaving an internal medial part thereof substantially free. For this purpose, the shell <NUM> is open, as well as at the bottom, also along the latero-medial axis X in a zone opposite the external lateral wall <NUM> and terminal of the upper wall <NUM> (<FIG>).

The external lateral wall <NUM> has a main development along the mandibular branch <NUM> and is substantially parallel or subparallel to the median plane of the body.

Optionally, the external lateral wall <NUM> can be provided with at least one through hole <NUM> for the insertion of an attachment element, for example a screw <NUM> (see for example <FIG> and <FIG>). The screw <NUM> allows to obtain a primary stabilization of the first prosthetic component <NUM> at least during the period of osseointegration thereof with the mandibular condyle of the patient. The size and length of the screw <NUM> vary according to the conformation and sizes of the condyle.

In the embodiment described here, with particular reference to <FIG> and <FIG>, the shell <NUM> also comprises a pair of opposite walls, respectively an anterior wall <NUM> and a posterior wall <NUM>, configured to at least partly wrap the condyle anteriorly and posteriorly in order to guarantee greater stability. The anterior <NUM> and posterior wall <NUM> are connected at the upper part to the upper wall <NUM>, respectively on one side and the other of the latter, and laterally to the external lateral wall <NUM>.

Although the upper wall <NUM>, the external lateral wall <NUM> and the anterior <NUM> and posterior walls <NUM> have been described as distinct and separate elements, it goes without saying that they can be made in a single body so that one can be an extension of the other, according to the geometry and the reciprocal disposition just described.

According to some embodiments described here, the anchoring element <NUM> is configured as a lamella <NUM> attached at the upper part to the upper wall <NUM>, on the side of the concave portion <NUM>, and laterally to the external lateral wall <NUM>. However, it is not excluded that the lamella <NUM> can be attached only to the upper part <NUM>. The lamella <NUM> can be conformed as a wall, a septum, a suitably shaped ridge projecting from the upper wall <NUM>.

In particular, the lamella <NUM> projects in a direction substantially orthogonal to the upper wall <NUM> (<FIG> and <FIG>). The lamella <NUM> divides the coupling seating <NUM> substantially into two parts, each of which is able to rest on a respective portion of condyle <NUM> located on the sides of the anchoring seating <NUM> (<FIG>).

The lamella <NUM> has a longitudinal extension, or length, L (<FIG>) in the direction of the latero-medial axis X substantially equal to the extension of the upper wall <NUM> in the same direction (<FIG>).

However, it is not excluded that the lamella <NUM> may also have a shorter length L. Evidently, the greater the length L, the greater the useful surface in contact with the bone of the condyle for a better integration and stabilization.

The lamella <NUM> has a height H (<FIG>) proportional to the depth of the anchoring seating <NUM> (<FIG>) provided on the condyle <NUM>. For example, the height H can have a minimum value of <NUM>, or be larger.

The lamella <NUM> has a thickness W1 (<FIG>) much smaller than the length L. For example, the thickness W1 can vary between about <NUM> and about <NUM>. Favorably, the thickness W1 is comprised between about <NUM> and about <NUM>.

Advantageously, the lamella <NUM> is configured to promote the primary stabilization of the prosthesis, the neoformation of cancellous bone and the osseointegration with the cortical bone of the condyle <NUM>.

In particular, the lamella <NUM> can have a substantially rectangular shape and be provided with macro grooves and micro grooves to promote the neoformation of cancellous bone and the osseointegration with the cortical bone of the condyle <NUM>.

In one embodiment, <FIG>, the lamella <NUM> is provided with a plurality of teeth <NUM> suitably inter-spaced to define the macro grooves as above, in such a way as to promote, during use, bone growth inside them in order to guarantee a greater stability of the first prosthetic component <NUM>. For example, the lamella <NUM> and the teeth <NUM> define a comb-like conformation.

The lamella <NUM> can also be provided with a chamfer <NUM> able to facilitate the latero-medial insertion of the first prosthetic component <NUM> in the anchoring seating <NUM> on the condyle <NUM>. In this case, <FIG>, the shape of the lamella <NUM> can be a rectangle trapezoid in which the inclined side that defines the chamfer <NUM> can also have more than one inclination or be defined by a curve.

According to some embodiments, the first prosthetic component <NUM> is made with a biocompatible material, for example titanium or an alloy thereof, or other possible known or unknown biocompatible materials. Advantageously, the articulating surface of this first prosthetic component <NUM> can be treated so that it is as smooth as possible, for example mirror-like, in order to reduce frictions during joint movement to a minimum.

In particular, the lamella <NUM> can be made of titanium, and its surface can be favorably treated to increase the contact surface with the bone and promote osseointegration with the latter. For example, the surface of the lamella <NUM> can be treated with a sandblasting process with hydroxyapatite and acid passivation (RBM). In possible embodiments, the lamella <NUM> can, alternatively and for the purposes of osseointegration, have an at least partly porous or lattice-shaped structure, which for example reproduces the trabecular structure of the bone, possibly associated with a portion of compact material.

The best osseointegration is also promoted by the piezo surgical preparation of the surgical site, which provides a preservation of the bone tissues and much less damage than a traditional cutter for the preparation of an osteotomy site.

In some embodiments, the first prosthetic component <NUM> can be made with a Selective Laser Melting (SLM) process, or with a Direct Metal Laser Sintering (DMSL) process, or again by means of Electron Beam Melting (EBM) technique, or in general by means of a suitable "additive manufacturing" or 3D printing technique, based on the specific anatomical needs of the patient. Such techniques, for example, are advantageous in the event the first prosthetic component <NUM>, and in particular the lamella <NUM>, at least partly have an at least partly porous or lattice-shaped structure, for example trabecular, possibly associated with a portion of compact material.

According to the embodiment shown in <FIG>, the second prosthetic component <NUM> can be configured as a fossa prosthesis configured to cover the glenoid fossa of the patient.

The second prosthetic component <NUM> comprises an articulating portion <NUM> able to cooperate, during use, with the convex portion <NUM> of the first prosthetic component <NUM>, and a zygomatic portion <NUM> which, during use, is able to cover the zygomatic arch of the patient.

The articulating portion <NUM> has a convex articulating surface <NUM> having a shape mating with the convex portion <NUM>.

The upper part of the articulating portion <NUM>, the one which, during use, is positioned in contact with the glenoid fossa of the patient, has a shape that traces the pre-existing, or surgically shaped, bone surface of the fossa.

The second prosthetic component <NUM> can be stabilized to the temporal bone by means of screws <NUM>. For this purpose, both the articulating portion, in an outermost part thereof, and also the zygomatic portion <NUM> can provide through holes <NUM> for the screws <NUM>. In the example described here, the zygomatic portion <NUM> is stabilized with three screws <NUM>.

According to some embodiments, the second prosthetic component <NUM> is made with a biocompatible material, for example ultra-high molecular weight polyethylene (UHMWPE), or other possible known and unknown biocompatible materials.

In accordance with the embodiment described in <FIG>, the guide device, in this specific case a surgical template, <NUM> comprises a central body <NUM> able to wrap at least the upper lateral part of the condylar branch, and a guide wall <NUM> attached at the upper part to the central body <NUM> and having the profile of the osteotomy to be performed on the condyle <NUM> of the patient. In particular, the central body <NUM> can be suitable to also partly wrap the posterior and anterior surfaces of the condyle <NUM> for a better positioning.

The surgical template <NUM> has a central vertical groove <NUM> open at the upper part which divides the guide wall <NUM> into a first guide branch 37a and a second guide branch 37b.

In the example described here, the guide wall <NUM> has a substantially curved profile, however, it is not excluded that the guide wall <NUM> may have a squared profile, or other profile suitable to make the least invasive osteotomy possible.

The vertical groove <NUM> is through in a direction parallel to the latero-medial axis X in order to allow the surgeon to perform a vertical osteotomy in order to prepare the anchoring seating <NUM> in the condyle <NUM> of the patient.

The guide groove <NUM> can also extend, in part, in the central body <NUM>.

The groove <NUM> is open at the upper part and has a terminal part, or bottom, <NUM> able to act as an abutment for the surgical blade during the preparation of the anchoring seating <NUM> (<FIG>).

The groove <NUM> has a depth D substantially equal to the height H of the lamella <NUM> of the first prosthetic component <NUM>, and a width W2 smaller than or equal to the thickness W1 of the lamella <NUM> (<FIG>). Furthermore, it is possible to provide a slight tapering that goes from the upper aperture of the groove <NUM> to the terminal part <NUM> thereof.

The surgical template <NUM> is provided with at least one calibrated hole <NUM> prepared through the central body <NUM>. The calibrated hole <NUM> allows to prepare a corresponding hole in the condyle <NUM> of the patient to position a screw which serves to stabilize the surgical template <NUM> and subsequently to attach the first prosthetic component <NUM>. In possible implementations, the condylar prosthetic component, that is, the condyle <NUM>, can be modeled and shaped in its external lateral part in order to house more attachment screws and, for this purpose, this can also provide the use of a dedicated template.

Operatively, after the identification of the part of the condyle <NUM> to be removed, the surgical template <NUM>, having profiles suitably shaped according to the anatomical needs of the patient, is positioned on the condylar branch <NUM> and attached to it with a screw (not shown) (<FIG>). Subsequently, a first osteotomy is performed following the profile of the guide wall <NUM> and then a second vertical osteotomy is performed along the groove <NUM> to create the anchoring seating <NUM> (<FIG>) to house the lamella <NUM>. Favorably, the osteotomies are performed using a blade with piezoelectric handle, guaranteeing maximum cutting precision.

It is clear that modifications and/or additions of parts may be made to the prosthetic device for temporomandibular joint and corresponding prosthetic assembly as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of prosthetic device for temporomandibular joint and corresponding prosthetic assembly, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claim 1:
Prosthetic device (<NUM>) for temporomandibular joint comprising a first prosthetic component (<NUM>), able to be associated with a mandibular condyle (<NUM>) of a patient, and a coordinated second prosthetic component (<NUM>), able to be associated with a respective glenoid fossa of said patient, wherein said first prosthetic component (<NUM>) is configured to cooperate with said second prosthetic component (<NUM>) to define said temporomandibular joint and comprises a concave portion (<NUM>), defining a coupling seating (<NUM>) having a shape mating with the shape of said mandibular condyle, characterized in that said first prosthetic component (<NUM>) comprises at least one anchoring element (<NUM>) projecting from, and attached at least to, said concave portion (<NUM>), being contained in said concave portion (<NUM>), said anchoring element (<NUM>) having a main extension along a latero-medial axis (X) and being configured to be inserted into a mating anchoring seating (<NUM>) present on said mandibular condyle (<NUM>), and in that said coupling seating (<NUM>) is at least partly open along said latero-medial axis (X).