PROSTHETIC DEVICE FOR TEMPOROMANDIBULAR JOINT AND CORRESPONDING PROSTHETIC ASSEMBLY

Abstract

Prosthetic device (10) for temporomandibular joint comprising a first prosthetic component (11), able to be associated with a mandibular condyle (112) of a patient, and a coordinated second prosthetic component (12), able to be associated with a respective glenoid fossa of the patient.

The present invention also concerns a guide device (35) for making an anchoring seating (113) for positioning the first component, and a prosthetic assembly comprising the prosthetic device (10) and the guide device (35).

Claims

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

2. Prosthetic device as in claim 1, wherein said first prosthetic component further comprises an external lateral portion configured to couple laterally with said condyle.

3. Prosthetic device as in claim 1, that wherein said first prosthetic component comprises a shell having an upper wall and an external lateral wall, disposed inclined with respect to said upper wall, wherein said shell is open, as well as at the bottom, also along said latero-medial axis in a zone opposite said external lateral wall and terminal of said upper wall.

4. Prosthetic device as in claim 3, wherein said anchoring element is configured as a lamella fixed at the upper part to said upper wall, on the side of said concave portion, and laterally to said external lateral wall, said lamella projecting in a direction substantially orthogonal to said upper wall.

5. Prosthetic device as in claim 4, wherein said lamella has a longitudinal extension, or length, in the direction of said latero-medial axis substantially equal to the extension of said upper wall.

6. Prosthetic device as in claim 5, wherein said lamella is configured to promote the primary stabilization of the prosthesis, the neoformation of cancellous bone and the osseointegration with the cortical bone of said condyle.

7. Prosthetic device as in claim 6, wherein said lamella is provided with macro grooves and micro grooves to promote the neoformation of cancellous bone and the osseointegration with the cortical bone of said condyle.

8. Prosthetic device as in claim 7, wherein said lamella is provided with a plurality of teeth suitably interspaced to define said macro grooves.

9. Guide device for preparing an anchoring seating for a prosthetic device as in claim 1, comprising 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 said central body and having the profile of the osteotomy to be performed on said condyle , wherein a groove extends vertically from said guide wall toward said central body, and in that said groove is open at the upper part and is through in a direction parallel to a latero-medial axis , and in that said groove has a depth substantially the same as a height of a lamella which acts as an anchoring element of said prosthetic device.

10. Guide device as in claim 9, wherein said groove divides said guide wall into a first guide branch and a second guide branch.

11. Guide device as in claim 9, that wherein said groove has a terminal part, or bottom , able to act as an abutment for a surgical blade.

12. Prosthetic assembly for temporomandibular joint comprising a prosthetic device and a guide device wherein said prosthetic device includes 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 said patient, wherein said first prosthetic component is configured to cooperate with said second prosthetic component to define said temporomandibular joint and comprises a concave portion, defining a coupling seating [having a shape mating with the shape of said mandibular condyle, wherein said first prosthetic component includes at least one anchoring element projecting from, and attached at least to, said concave portion, being contained in said concave portion, said anchoring element having a main extension along a latero-medial axis and being configured to be inserted into a mating anchoring seating present on said mandibular condyle, and in that said coupling seating is at least partly open along said latero-medial axis, and wherein the guide device includes 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 said central body and having the profile of the osteotomy to be performed on said condyle, wherein a groove extends vertically from said guide wall toward said central body, and in that said groove is open at the upper part and is through in a direction parallel to a latero-medial axis, and in that said groove has a depth substantially the same as a height of a lamella which acts as an anchoring element of said prosthetic device.

13. Guide device as in claim 10, wherein said groove has a terminal part, or bottom, able to act as an abutment for a surgical blade.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

[0031] - FIG. 1 is a perspective view of a prosthetic device for temporomandibular joint in accordance with the embodiment described here;

[0032] - FIG. 2 is a perspective view of the first prosthetic component of the prosthetic device of FIG. 1;

[0033] - FIG. 3 is a perspective view of the second prosthetic component of the prosthetic device of FIG. 1;

[0034] - FIG. 4 is a lateral view of the anchoring element of FIG. 2;

[0035] - FIG. 5 is a perspective view showing the coupling of the first prosthetic component with the mandibular condyle;

[0036] - FIG. 6 is an external lateral plan view of the first prosthetic component during use;

[0037] - FIG. 7 is an internal lateral plan view of the first prosthetic component during use;

[0038] - FIG. 8 is a front view of the first prosthetic component during use;

[0039] - FIG. 9 is a perspective view of a guide device in accordance with the embodiment described here;

[0040] - FIGS. 10-11 are perspective views that show the functioning of the guide device of FIG. 9.

[0041] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

[0042] 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.

[0043] Before describing these embodiments, we must also clarify that the present description is not limited in its application to details of the construction and disposition of the components as described in the following description using the attached drawings. The present description can provide other embodiments and can be obtained or executed in various other ways. We must also clarify that the phraseology and terminology used here is for the purposes of description only, and cannot be considered as limitative.

[0044] Some embodiments described here concern a prosthetic device 10 for temporomandibular joint (FIGS. 1-7) and a guide device 35 (FIGS. 9-11) required to prepare a specific anchoring seating 113 (FIG. 11) for the prosthetic device 10, 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 10 and the guide device 35.

[0045] 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.

[0046] With particular reference to FIG. 1, the temporomandibular joint articulates the mandibular bone 111 with the temporal bone 110, in particular it connects a mandibular condyle (FIG. 5), hereafter condyle, 112 with a respective glenoid fossa of the temporal bone 110, hereafter fossa.

[0047] The prosthetic device 10 therefore comprises a first prosthetic component 11, able to be associated with a condyle 112 of a patient, and a coordinated second prosthetic component 12, able to be associated with a respective fossa of the patient. In particular, the condyle 112 is suitably shaped to house the first prosthetic component 11, as will be described in more detail below.

[0048] The first prosthetic component 11 comprises a concave portion 13, defining a coupling seating 14 having a shape mating with the shape of the previously shaped condyle 112.

[0049] The first component 11 comprises a convex portion 15, opposite the concave portion 13 and configured to couple with the second prosthetic component 12 to define the temporomandibular j oint.

[0050] The first prosthetic component 11 is provided with at least one anchoring element 16 projecting from, and attached at least to, the concave portion 13. The anchoring element 16 has an overall size such as to be substantially contained inside the concave portion 13.

[0051] The anchoring element 16 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.

[0052] The anchoring element 16 is configured to be inserted in a mating anchoring seating 113 (FIG. 11) made on the condyle 112 of the patient which is shaped following the profile of the guide device 35 which will be described below.

[0053] The coupling seating 14 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 11 with the condyle 112 in a direction parallel to the latero-medial axis, which runs from the outside to the inside (FIG. 2, FIG. 5 and FIGS. 7-8). In the embodiment described here, the coupling seating 14 has a shape substantially mating with the articulating upper portion of the condyle 112.

[0054] The particular geometry of the prosthetic device 10 and in particular of the first prosthetic component 11 provided with the anchoring element 16 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.

[0055] According to some embodiments described here, with particular reference to FIGS. 2, 5 and 8, the first prosthetic component 11 also comprises an external lateral portion 17 configured to couple laterally with the condyle 112. The external lateral portion 17 has an extension such as to allow a lateral abutment during the positioning of the first prosthetic component 11 along the lateromedial axis X, and to allow a stabilization thereof.

[0056] The first prosthetic component 11 can be configured as a condyle prosthesis configured to at least partly cover the condyle 112 of the patient. This first prosthetic component 11 is conceived as a covering prosthesis with the purpose of preserving the original bone portion of the condyle 112 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.

[0057] In particular, the first prosthetic component 11 is configured to cover the lateral surface of the condyle 112, 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 11, that is, in a direction parallel to the latero-medial axis X, it is not provided to cover the medial portion of the condyle 112 (FIGS. 7-8).

[0058] With particular reference to FIG. 2, the first prosthetic component 11 comprises a shell 18 having an upper wall 19 and an external lateral wall 20 disposed inclined with respect to the upper wall 19. The inclination of the external lateral wall 20 is essentially given by the anatomy of the mandibular branch 114 of the patient. In the example embodiment described here, this inclination is about 90 °, or slightly smaller.

[0059] The upper wall 19 has a shape such as to define, at the bottom, the concave portion 13 and, at the upper part, the convex portion 15 (FIG. 2 and FIG. 7).

[0060] The upper wall 19 is configured to at least partly cover the condyle leaving an internal medial part thereof substantially free. For this purpose, the shell 18 is open, as well as at the bottom, also along the latero-medial axis X in a zone opposite the external lateral wall 20 and terminal of the upper wall 19 (FIGS. 7-8).

[0061] The external lateral wall 20 has a main development along the mandibular branch 114 and is substantially parallel or subparallel to the median plane of the body.

[0062] Optionally, the external lateral wall 20 can be provided with at least one through hole 21 for the insertion of an attachment element, for example a screw 22 (see for example FIG. 2 and FIGS. 5-6). The screw 22 allows to obtain a primary stabilization of the first prosthetic component 11 at least during the period of osseointegration thereof with the mandibular condyle of the patient. The size and length of the screw 22 vary according to the conformation and sizes of the condyle.

[0063] In the embodiment described here, with particular reference to FIG. 2 and FIG. 7, the shell 18 also comprises a pair of opposite walls, respectively an anterior wall 23 and a posterior wall 24, configured to at least partly wrap the condyle anteriorly and posteriorly in order to guarantee greater stability. The anterior 23 and posterior wall 24 are connected at the upper part to the upper wall 19, respectively on one side and the other of the latter, and laterally to the external lateral wall 20.

[0064] Although the upper wall 19, the external lateral wall 20 and the anterior 23 and posterior walls 24 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.

[0065] According to some embodiments described here, the anchoring element 16 is configured as a lamella 25 attached at the upper part to the upper wall 19, on the side of the concave portion 13, and laterally to the external lateral wall 20. However, it is not excluded that the lamella 25 can be attached only to the upper part 19. The lamella 25 can be conformed as a wall, a septum, a suitably shaped ridge projecting from the upper wall 19.

[0066] In particular, the lamella 25 projects in a direction substantially orthogonal to the upper wall 19 (FIG. 2 and FIG. 7). The lamella 25 divides the coupling seating 14 substantially into two parts, each of which is able to rest on a respective portion of condyle 112 located on the sides of the anchoring seating 113 (FIG. 11).

[0067] The lamella 25 has a longitudinal extension, or length, L (FIG. 4) in the direction of the latero-medial axis X substantially equal to the extension of the upper wall 19 in the same direction (FIG. 2).

[0068] However, it is not excluded that the lamella 25 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.

[0069] The lamella 25 has a height H (FIG. 4) proportional to the depth of the anchoring seating 113 (FIG. 11) provided on the condyle 112. For example, the height H can have a minimum value of 4 mm, or be larger.

[0070] The lamella 25 has a thickness W1 (FIG. 7) much smaller than the length L. For example, the thickness W1 can vary between about 1 mm and about 4 mm. Favorably, the thickness W1 is comprised between about 2 mm and about 3 mm.

[0071] Advantageously, the lamella 25 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 112.

[0072] In particular, the lamella 25 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 112.

[0073] In one embodiment, FIGS. 2 and 4, the lamella 25 is provided with a plurality of teeth 26 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 11. For example, the lamella 25 and the teeth 26 define a comb-like conformation.

[0074] The lamella 25 can also be provided with a chamfer 29 able to facilitate the latero-medial insertion of the first prosthetic component 11 in the anchoring seating 113 on the condyle 112. In this case, FIG. 4, the shape of the lamella 25 can be a rectangle trapezoid in which the inclined side that defines the chamfer 29 can also have more than one inclination or be defined by a curve.

[0075] According to some embodiments, the first prosthetic component 11 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 11 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.

[0076] In particular, the lamella 25 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 25 can be treated with a sandblasting process with hydroxyapatite and acid passivation (RBM). In possible embodiments, the lamella 25 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.

[0077] 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.

[0078] In some embodiments, the first prosthetic component 11 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 11, and in particular the lamella 25, at least partly have an at least partly porous or lattice-shaped structure, for example trabecular, possibly associated with a portion of compact material.

[0079] According to the embodiment shown in FIG. 1 and FIG. 3, the second prosthetic component 12 can be configured as a fossa prosthesis configured to cover the glenoid fossa of the patient.

[0080] The second prosthetic component 12 comprises an articulating portion 30 able to cooperate, during use, with the convex portion 15 of the first prosthetic component 11, and a zygomatic portion 31 which, during use, is able to cover the zygomatic arch of the patient.

[0081] The articulating portion 30 has a convex articulating surface 32 having a shape mating with the convex portion 15.

[0082] The upper part of the articulating portion 30, 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.

[0083] The second prosthetic component 12 can be stabilized to the temporal bone by means of screws 34. For this purpose, both the articulating portion, in an outermost part thereof, and also the zygomatic portion 31 can provide through holes 33 for the screws 34. In the example described here, the zygomatic portion 31 is stabilized with three screws 34.

[0084] According to some embodiments, the second prosthetic component 12 is made with a biocompatible material, for example ultra-high molecular weight polyethylene (UHMWPE), or other possible known and unknown biocompatible materials.

[0085] In accordance with the embodiment described in FIGS. 9-11, the guide device, in this specific case a surgical template, 35 comprises a central body 36 able to wrap at least the upper lateral part of the condylar branch, and a guide wall 37 attached at the upper part to the central body 36 and having the profile of the osteotomy to be performed on the condyle 112 of the patient. In particular, the central body 36 can be suitable to also partly wrap the posterior and anterior surfaces of the condyle 112 for a better positioning.

[0086] The surgical template 35 has a central vertical groove 38 open at the upper part which divides the guide wall 37 into a first guide branch 37a and a second guide branch 37b.

[0087] In the example described here, the guide wall 37 has a substantially curved profile, however, it is not excluded that the guide wall 37 may have a squared profile, or other profile suitable to make the least invasive osteotomy possible.

[0088] The vertical groove 38 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 113 in the condyle 112 of the patient.

[0089] The guide groove 38 can also extend, in part, in the central body 36.

[0090] The groove 38 is open at the upper part and has a terminal part, or bottom, 39 able to act as an abutment for the surgical blade during the preparation of the anchoring seating 113 (FIG. 11).

[0091] The groove 38 has a depth D substantially equal to the height H of the lamella 25 of the first prosthetic component 11, and a width W2 smaller than or equal to the thickness W1 of the lamella 25 (FIG. 11). Furthermore, it is possible to provide a slight tapering that goes from the upper aperture of the groove 38 to the terminal part 39 thereof.

[0092] The surgical template 35 is provided with at least one calibrated hole 40 prepared through the central body 36. The calibrated hole 40 allows to prepare a corresponding hole in the condyle 112 of the patient to position a screw which serves to stabilize the surgical template 35 and subsequently to attach the first prosthetic component 11. In possible implementations, the condylar prosthetic component, that is, the condyle 112, 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.

[0093] Operatively, after the identification of the part of the condyle 112 to be removed, the surgical template 35, having profiles suitably shaped according to the anatomical needs of the patient, is positioned on the condylar branch 114 and attached to it with a screw (not shown) (FIG. 10). Subsequently, a first osteotomy is performed following the profile of the guide wall 37 and then a second vertical osteotomy is performed along the groove 38 to create the anchoring seating 113 (FIG. 11) to house the lamella 25. Favorably, the osteotomies are performed using a blade with piezoelectric handle, guaranteeing maximum cutting precision.

[0094] 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.

[0095] 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.

[0096] In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.