WO2014043452A1

WO2014043452A1 - Temporomandibular joint implants

Info

Publication number: WO2014043452A1
Application number: PCT/US2013/059627
Authority: WO
Inventors: Patrick J. LOUIS; Jack Lemons
Original assignee: The Uab Research Foundation
Priority date: 2012-09-13
Filing date: 2013-09-13
Publication date: 2014-03-20

Abstract

In one embodiment, a temporomandibular joint implant includes a fossa component including a base portion and a flange portion that extends upward from the base portion and a mandibular component including a body portion and a head portion that extends inward from the body portion, wherein at least one of the components comprises a ridge that stabilizes the component when it is implanted.

Description

TEMPOROMANDIBULAR JOINT IMPLANTS

Cross -Reference to Related Application(s)

This application claims priority to co-pending U.S. Provisional Application serial number 61/700,616, filed September 13, 2012, which is hereby incorporated by reference herein in its entirety.

Background

The temporomandibular joint (TMJ) is a complex joint having more degrees of movement than rotating joints, such as the knees, hips, and shoulders. The TMJ enables the sliding, hinging, and lateral movement of the jaw and undergoes more loading and unloading cycles than any other joint in the body.

The TMJ can be affected by a number of conditions including trauma, damage to the floating disc between the bones, arthritis, and various other forms of degenerative diseases that can cause it to lose proper functionality. Such conditions often lead to patient pain and loss of patient quality of life. In such situations, surgical intervention in the form of joint replacement with a TMJ implant may be necessary. TMJ implants are often relatively cumbersome and typically require the removal of a large portion of the condyle of the mandible, as depicted in Fig. 1 , for proper implant function. Although such removal is common, it is undesirable because the pterygoid muscle that helps to control translation (i.e., side-to-side movement) of the jaw attaches to the condyle region. Therefore, when all or a large part of the condyle is removed, the pterygoid muscle attachment is likewise removed and the patient loses the ability to adequately maintain three-dimensional translation of the jaw. Among other things, this has a detrimental effect upon craniofacial stability and mastication.

In many cases, the patient may have a healthy condylar bone and would benefit from TMJ resurfacing as opposed to TMJ replacement. In such a case, less bone could be removed and the lateral pterygoid muscle could be preserved. Unfortunately, current implants are not designed for such applications. It can therefore be appreciated that it would be desirable to have alternative TMJ implants and implant procedures that enable less bone removal and the preservation of the pterygoid muscle attachment.

Brief Description of the Drawings

The present disclosure may be better understood with reference to the following figures. Matching reference numerals designate corresponding parts throughout the figures, which are not necessarily drawn to scale.

Fig. 1 is a side view of a human skull illustrating removal of a large portion of the condyle in a typical temporomandibular joint (TMJ) procedure.

Fig. 2 is an exploded perspective view of a first embodiment of a TMJ implant. Fig. 3 is a top/inner perspective view of a fossa component of the TMJ implant of Fig. 2.

Fig. 4 is a bottom/inner perspective view of the fossa component of Fig. 3. Fig. 5 is an outer/top perspective view of the fossa component of Fig. 3.

Fig. 6 is an outer/side perspective view of the fossa component of Fig. 3.

Fig. 7 is an inner view of the fossa component of Fig. 3.

Fig. 8 is an outer view of the fossa component of Fig. 3.

Fig. 9 is a side view of the fossa component of Fig. 3.

Fig. 10 is a first inner/bottom perspective view of a mandibular component of the TMJ implant of Fig. 2.

Fig. 1 1 is a second inner/bottom perspective view of the mandibular component of Fig. 0.

Fig. 12 is an outer/top perspective view of the mandibular component of Fig.

10.

Fig. 13 is a top/inner perspective view of the mandibular component of Fig.

10.

Fig. 14 is an inner view of the mandibular component of Fig. 10.

Fig. 15 is an outer view of the mandibular component of Fig. 10.

Fig. 16 is a side view of the mandibular component of Fig. 10.

Fig. 17 is a top view of the mandibular component of Fig. 10.

Fig. 18 is a bottom view of the mandibular component of Fig. 10.

Figs. 19A and 19B are side views of a human skull that respectively illustrate preparation of the mandible and implantation of the TMJ implant of Fig. 2.

Fig. 20 is an exploded top/inner perspective view of a fossa component of a second embodiment of a TMJ implant.

Fig. 21 is a top view of the fossa component of Fig. 20. Fig. 22 is an inner view of the fossa component of Fig. 20.

Fig. 23 is an outer view of the fossa component of Fig. 20.

Fig. 24 is a side view of the fossa component of Fig. 24.

Fig. 25 is a top view of a mandibular component of the second embodiment of the TMJ implant.

Fig. 26 is an outer view of the mandibular component of Fig. 25.

Fig. 27 is a side view of the mandibular component of Fig. 25.

Fig. 28 is an inner view of the mandibular component of Fig. 25.

Fig. 29 is a bottom view of the mandibular component of Fig. 25.

Detailed Description

As described above, it would be desirable to have alternative temporomandibular joint (TMJ) implants for performing TMJ procedures. For example, it would be desirable to have a TMJ implant that enables the pterygoid muscle attachment to the condyle to be preserved when performing a TMJ procedure. Disclosed herein are TMJ implants that can be used in TMJ resurfacing or replacement procedures that accomplish this goal and, at least in some embodiments, ensure that the attachment of the pterygoid muscle remains intact.

In the following disclosure, various specific embodiments are described. It is to be understood that those embodiments are example implementations of the disclosed inventions and that alternative embodiments are possible. All such embodiments are intended to fall within the scope of this disclosure.

Fig. 2 illustrates a first embodiment of a TMJ implant 10 that can be used to resurface or replace the TMJ of a patient. As shown in Fig. 2, the TMJ implant 10 generally comprises a fossa component 12 and a mandibular component 14. In some embodiments, the fossa component 12 and the mandibular component 14 are both made from a biocompatible metal (cast or wrought), such as an iron alloy (e.g., stainless steel), titanium or a titanium alloy, a cobalt alloy (cast or wrought form), or a zirconium alloy.

Figs. 3-9 illustrate the fossa component 12 from multiple perspectives. As is shown in those figures, the fossa component 2 generally comprises a base portion 16 and a flange portion 18. In some embodiments, the base portion 16 is generally rectangular and has a width dimension of approximately 20 to 35 millimeters (mm) and a depth dimension of approximately 20 to 35 mm (in the context of the component as implanted; see Fig. 19B). As is shown in Fig. 3, the inner corners 20 of the base portion 16 can be rounded.

The bottom surface 22 of the base portion 16 forms a bearing surface of the fossa component 12 and is concavely rounded to enable the mandibular component 14 to roll, rotate, and slide relative to the fossa component without translating out of engagement with that component. By way of example, the bottom surface 22 has a radius of curvature of approximately 1 to 20 centimeters (cm). In some embodiments, the bottom surface 22 can be processed or coated with another material to improve the wear characteristics of the bottom surface. For example, a hard material such as carbon can be incorporated into the bottom surface 22 through an ion implantation process or can be applied to the bottom surface as a film.

With further reference to Fig. 3, the top surface 24 of the base portion 16 can be generally planar. In some embodiments, extending upward from the top surface 24 is a linear ridge 26 that extends along the top surface from the flange portion 18 to an inner edge 28 of the base portion 16. As shown in Fig. 3, the ridge 26 optionally can be offset to one lateral side of the base portion 16. Regardless, a similarly dimensioned groove or notch can be formed in the patient's temporal bone in a direction normal to the skull to accommodate the ridge 26, and the fossa component 12 can therefore be more rigid, stable, and secure once mounted to the skull. As is also shown in Fig. 3, fillets can be provided along the lateral edges of the ridge 26 where it meets the top surface 24 of the base portion 16.

In some embodiments, both the top surface 24 of the base portion 16 and the ridge 26 can have a micro- or nano-topography that incorporates a bioactive material that induces the on-growth and/or ingrowth of hard or soft tissue into the fossa component 12. By way of example, the top surface 24 can have a surface roughness of approximately 1 nanometer (nm) to 500 microns (μιτι) and can incorporate one or more bioactive compounds, such as a calcium phosphate, a titanium oxide or nitride, a carbon compound, a silicon compound, or the like. In other embodiments, the top surface 24 can alternatively or additionally comprise an organic substance, such as one or more mitogenic or morphogeneic factors (e.g., bone morphogenic protein (BMP), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), transforming growth factor (TGF)).

With further reference to Fig. 3, the flange portion 18 extends upward from the base portion 16 along an outer edge 30 of the base portion. In some embodiments, the flange portion 18 forms an approximately 90° angle with the base portion 16. The flange portion 18 can also be generally rectangular and can have a width dimension of approximately 20 to 30 mm and a height dimension of approximately 7 to 15 mm. A fillet can be provided along the top surface 24 of the base portion 16 where it meets the flange portion 18. Top corners 32 of the flange portion 18 can also be rounded like the inner corners 20 of the base portion 16.

Multiple openings 34 are provided through the flange portion 18 above the top surface 24 of the base portion 16 to enable the passage of screws (not shown) through the flange portion and into the temporal bone. In the illustrated example, the flange portion 18 comprises four such openings 34. In some embodiments, each opening 34 has a diameter of approximately 0.5 to 3 mm. As shown in Figs. 5, 6, and 8, each opening 34 can have a countersink 36 that provides space for a screw head.

Referring next to Figs. 0-18, the mandibular component 14 is illustrated from multiple perspectives. As shown in these figures, the mandibular component 14 generally comprises a body portion 40 and a head portion 42. The body portion 40 is elongated and generally rectangular. In some embodiments, the body portion 40 has a width dimension of approximately 15 to 25 mm and a height dimension of approximately 20 to 40 mm (in the context of the component as implanted). The body portion 40 is defined by an inner surface 44, an outer surface 46, and lateral edges 48. The body portion 40 can be curved about its longitudinal (vertical) axis so that the lateral edges 48 of the body portion 40 are slightly curved inward toward each other. By way of example, the body portion 40 (and the inner and outer surfaces 44 and 46) can have a radius of curvature of approximately 1 to 30 cm. The body portion 40 can also be angled relative to the horizontal direction, as is shown most clearly in Figs. 14 and 15. By way of example, the lateral edges 48 of the body portion 40 can form an angle of approximately 0 to 25° with the vertical direction.

In some embodiments, the inner surface 44 of the body portion 40 also has a micro- or nano-topography that incorporates a bioactive material that enhances the on-growth and/or ingrowth of tissue. By way of example, the inner surface 44 can have a surface roughness of approximately 1 nm to 500 pm and can incorporate one or more bioactive compounds, such as those listed above. Furthermore, the inner surface 44 can alternatively or additionally comprise one or more organic factors, such as those listed previously.

As shown in Figs. 0-15, multiple openings 50 are formed through the body portion 40 of the mandibular component 14. In the illustrated example, seven such openings 50 are provided. In some embodiments, each opening 50 has a diameter of approximately 0.5 to 3 mm and each is provided with a countersink 52 on the outer surface 46 to provide space for a screw head.

As shown best in Figs. 10-13 and 16, the head portion 42 extends inwardly from the body portion 40 (in the context of the component as implanted, see Fig. 19B). In some embodiments, the head portion 42 forms an approximately 90° angle with the body portion 40. The head portion 42 can also be generally rectangular and can have a width dimension of approximately 15 mm to 25 mm and a depth dimension of approximately 15 to 25 mm. As is shown best in Fig. 17, however, one of the four corners of the rectangle can be omitted to facilitate placement of the head portion 42 within the anatomy of the patient. A fillet can be provided along the inner surface 44 of the body portion 40 where it meets the head portion 42.

In some embodiments, the body portion 40 and the head portion 42 are joined by a linear ridge 54 that extends out from the inner surface 44 of the body portion toward an inner edge 56 of the head portion. As is shown best in Fig. 14, the ridge 54 can be offset to one lateral edge 48 of the body portion 40. Regardless, a similarly-dimensioned groove or notch can be formed in the remaining portion of the condyle of the mandible in a direction normal to the skull to accommodate the ridge 54 (see Fig. 19A). The mandibular component 14 can therefore be more rigid, stable, and secure once connected to the mandible. As shown in Figs. 10 and 11 , fillets can be provided along the edges of the ridge 54 where it meets the inner surface 44 of the body portion 40 and the bottom surface 58 of the head portion 42. In some embodiments, the ridge 54 and the bottom surface 58 of the head portion 42 are also provided with a micro- or nano-topography and a bioactive material that induces the on-growth and/or ingrowth of tissue.

A top surface 60 of the head portion 42 forms a bearing surface of the mandibular component 14. As is apparent from Figs. 14 and 15, the top surface 60 is convexly rounded to generally match the concave bottom surface 22 of the fossa component 12. By way of example, the top surface 60 has a radius of curvature of approximately 1 to 20 cm. In some embodiments, the top surface 60 can be processed or coated with a hard material, such as carbon, to improve the wear characteristics of the top surface.

Figs. 19A and 19B illustrate an example of implantation of the TMJ implant 10. Beginning with Fig. 19A, a portion of the condyle 72 of the mandible 70 is removed to make space for the implant 10. Significantly, only the superior portion of the condyle 72 is removed so that the attachment of the pterygoid muscle (not shown) remains intact. A vertical groove 74 is also formed in the condyle 72 to make space for the ridge 54 of the mandibular component 14. In addition, a portion of the temporal bone can be removed and a groove formed for the ridge 26 of the fossa component 12 (not shown).

Fig. 19B shows the TMJ implant 10 after it has been implanted. As shown in the figure, the implant 10 only replaces a small portion of the mandible and temporal bone and therefore can be said to provide resurfacing of the TMJ, as opposed to complete replacement. Because the implant 10 is small, it can, at least in some embodiments, be passed through a single incision, as opposed to two separate incisions as is the norm for TMJ replacement surgery.

Figs. 20-29 illustrate a second embodiment of a TMJ implant 80. The implant 80 is similar in many ways to the implant 10. Like features will therefore not be described again. Unlike the implant 10, however, the implant 80 is modular in design. More specifically, both the fossa component 82 and the mandibular component 100 comprise multiple subcomponents.

Figs. 20-24 illustrate the fossa component 82 from multiple perspectives. As shown in Fig. 20, the fossa component 82 comprises an upper part 84 and a lower part 86. The upper part 84 comprises the top surface 88, the ridge 90, and the flange portion 92, while the lower part 86 comprises the bottom surface 94, which forms the bearing surface of the fossa component 82. The lower part 86 connects to the upper part 84 using an appropriate connection mechanism. In the illustrated example, the connection mechanism is a dovetail joint 96 that includes a dovetail-shaped tongue provided on the top surface of the lower part 86 that can be received in a dovetail- shaped groove formed in the bottom surface of the upper part 84. Optionally, locking pins 95 can be inserted into passages formed by grooves 97, 99 provided in the upper and lower parts 84 and 86, respectively. When inserted into the passages, the pins 95 lock the upper and lower parts 84, 86 so that they cannot slide relative to each other.

With the above-described construction, the upper and/or lower parts 84, 86 can be interchangeable. Such interchangeability enables parts of different sizes to be used to suit the patient's anatomy. For example, multiple upper parts 84 and multiple lower parts 86 having different height dimensions (thicknesses) can be supplied in an implant kit. The surgeon can then select the upper part 84 and lower part 86 sizes that best suit the patient. In this manner, the fossa component 82 can be made to fit the patient's anatomy and not vice versa.

Figs. 25-29 illustrate the mandibular component 100 of the implant 80 from multiple perspectives. As is apparent from these figures, the mandibular component 100 is similar in many ways to the mandibular component 14 and therefore generally comprises a body portion 102 and a head portion 104. However, instead of having a bearing surface integrated into the head portion 104, a vertical post 106 extends upward from the head portion that is adapted to receive an interchangeable bearing member 108 that can seat on top of the post. The bearing member 108 includes a bearing surface 1 10 that is adapted to contact the bottom surface 94 of the fossa component 82. In some embodiments, the bearing surface 110 can also be processed or coated with a hard material that improves its wear characteristics. In some embodiments, the bearing member 108 can be designed so as to rotate or pivot relative to the post 106.

When such modularity is provided, the bearing member 108 can be interchanged with other bearing members 108 of different sizes. Therefore, multiple bearing members 108 can be provided to the surgeon and the correct-sized bearing member can be selected for implantation within the patient. In this manner, the mandibular component 00 can likewise be made to fit the patient's anatomy and not vice versa.

The TMJ implant 80 can be used for TMJ resurfacing in similar manner to the TMJ implant 10. However, the TMJ implant 80 may be even better suited for use in TMJ replacement procedures.

Claims

CLAIMS Claimed are:

1. A temporomandibular joint implant comprising:

a fossa component including a base portion and a flange portion that extends upward from the base portion; and

a mandibular component including a body portion and a head portion that extends inward from the body portion;

wherein at least one of the components comprises a ridge that stabilizes the component when it is implanted.

2. The temporomandibular joint implant of claim 1 , wherein the base portion of the fossa component comprises a concave bottom surface that acts as a bearing surface.

3. The temporomandibular joint implant of claim 2, wherein the bottom surface of the base portion comprises a hard material that resists wear.

4. The temporomandibular joint implant of claim 1 , wherein the fossa component comprises a linear ridge that extends upward from a top surface of the base portion.

5. The temporomandibular joint implant of claim 4, wherein the fossa component further comprises fillets provided along lateral edges of the ridge where the ridge meets the top surface.

6. The temporomandibular joint implant of claim 1 , wherein the flange portion of the fossa component includes openings that enable screws to pass through the flange portion.

7. The temporomandibular joint implant of claim 1 , wherein the body portion of the mandibular component has a height dimension of approximately 20 to 40 mm.

8. The temporomandibular joint implant of claim 1 , wherein the body portion of the mandibular component is inwardly curved.

9. The temporomandibular joint implant of claim 1 , wherein the head portion of the mandibular component has a convex top surface that acts as a bearing surface.

10. The temporomandibular joint implant of claim 9, wherein the top surface of the head portion comprises a hard material that resists wear.

11. The temporomandibular joint implant of claim 1 , wherein the body portion of the mandibular component includes openings that enable screws to pass through the body portion.

12. The temporomandibular joint implant of claim 1 , wherein the mandibular component further comprises a linear ridge that extends out from the body portion along a bottom surface of the head portion.

13. The temporomandibular joint implant of claim 12, wherein the mandibular component further comprises fillets provided along lateral edges of the ridge where the ridge meets the bottom surface.

14. The temporomandibular joint implant of claim 1 , wherein at least one of the surfaces of the fossa component and the mandibular component includes a bioactive material.

15. The temporomandibular joint implant of claim 1 , wherein the fossa component includes an upper part and lower part that can be connected to the upper part.

16. The temporomandibular joint implant of claim 15, wherein one of the parts includes a tongue and the other part includes a groove and wherein the parts connect by placing the tongue in the groove.

17. The temporomandibular joint implant of claim 1 , wherein the mandibular component includes a removable bearing member.

18. A method for performing a temporomandibular joint procedure, the method comprising:

removing only a superior portion of the condyle region of the mandible of a patient so as to leave the attachment of the pterygoid muscle to the mandible intact; forming grooves in the temporal bone and the mandible adapted to receive ridges of a fossa component and a mandibular component of a temporomandibular joint implant;

securing the fossa component to the temporal bone of the patient; and securing the mandibular component to the mandible of the patient.

19. The method of claim 18, wherein the ridges of the fossa and mandibular components extend inwardly into the patient's bone.

20. The method of claim 18, wherein the fossa component and the mandibular component are modular.