Orthognatic Sawing and Positioning Implant

Abstract

The invention concerns a bone joining implant (1) for joining of a first bone section (2) with a second bone section (3) of a mammal bone (4) with a first attachment area (6), displaying several holes for fastening elements (5a), prepared for attachment to the first bone section (2), and a second attachment area (7), linked to the first attachment area (6), with the second attachment area (7) also displaying several holes for fastening elements (5b), also prepared for attachment to the second bone section (3), with formation of a separating tool guidance contour (9) between the first and second attachment areas (6, 7), defining a cutting line (8), as well as a procedure for the individualized manufacture of such a bone joining implant (1).

Claims

1. A bone forming implant adapted to join a first bone section with a second bone section or several bone sections of a mammal bone, said bone joining implant comprising a first attachment area having holes for fastening elements for attachment of said first attachment area to the first bone section, a second attachment area linked to the first attachment area, with the second attachment area having several holes for fastening elements for attachment of said second attachment area to the second bone section, and a separating tool guidance contour defining a cutting line between the first and second attachment areas.

2. The bone joining implant of claim 1, wherein said separating tool guidance contour is bar shaped.

3. The bone joining implant of claim 1, wherein said separating tool guidance contour comprises a bridging bar linked with the first attachment area and/or the second attachment area.

4. The bone joining implant of claim 1, wherein said separating tool guidance contour comprises a frame structure formed between the first and second attachment areas.

5. The bone joining implant of claim 1, the attachment areas and the separating tool guidance contour being made from the same substance.

6. The bone joining implant of claim 1, the bone joining implant being manufactured from a metal substance, preferably a titanium substance.

7. The bone joining implant of claim 1, further comprising a second separating tool guidance contour positioned between the second attachment area and a third attachment area, said second separating tool guidance contour defining a cutting line (17) between said second and third attachment areas, with the third attachment area having holes for fastening elements for attachment of said third attachment area to the first bone section.

8. The bone joining implant of claim 1, wherein said mammal bone is a maxilla bone or mandible bone.

9. A method for the individualized manufacture of the bone joining implant of claim 1, comprising the following steps: a) Obtaining a 3D model of the existing condition of the mammal bone in a first data set; b) Creation of a 3D target model with a second data set, defining at least one cutting line on the 3D model of the existing condition and relative shifting of two imaginary bone sections, in relation to each other, separated by at least one cutting line, and c) Manufacture of the bone joining implant based on the 3D target model, where the first attachment area for attachment to the first bone section of the 3D target model, the second attachment area for attachment to the second bone section of the 3D target model and the separating tool guidance contour are formed by, at least, partial recreation of at least one cutting line.

10. The bone joining implant of claim 2, wherein said separating tool guidance contour comprises a bridging bar linked with the first attachment area and/or the second attachment area.

11. The bone joining implant of claim 10, wherein said separating tool guidance contour comprises a frame structure formed between the first and second attachment areas.

12. The bone joining implant of claim 11, the attachment areas and the separating tool guidance contour being made from the same substance.

13. The bone joining implant of claim 12, the bone joining implant being manufactured from a metal substance, preferably a titanium substance.

14. The bone joining implant of claim 13, wherein said mammal bone is a maxilla bone or mandible bone.

15. The bone joining implant of claim 7, wherein said first separating tool guidance contour comprises a frame structure formed between the first and second attachment areas and said second separating tool guidance contour comprises a second frame structure formed between the second and third attachment areas.

16. The bone joining implant of claim 15, the attachment areas and the separating tool guidance contours being made from the same substance.

17. The bone joining implant of claim 16, the bone joining implant being manufactured from a metal substance, preferably a titanium substance.

18. The bone joining implant of claim 17, wherein said mammal bone is a maxilla bone or mandible bone.

Description

[0027] In the following, the invention is further described based on diagrams, showing in

[0028] FIG. 1 an isometric representation of a bone joining implant, based on the invention, in accordance with a favorable design model, displaying particularly well a first and second attachment area as well as a (first) separating tool guidance contour formed along a bridge of the first attachment area;

[0029] FIG. 2 a frontal view of the bone joining implant shown in FIG. 1, now showing in addition to the first and second attachment areas an additional, third attachment area, also linked to the second attachment area, with the third attachment area also displaying a bridge forming a (second) separating tool guidance contour;

[0030] FIG. 3 a frontal view of a 3D model of a mammal bone, formed as a human skull, based on the existing condition, with the first and third attachment areas of the bone joining implant according to FIGS. 1 and 2, respectively, and based on the two subordinate, detailed representations attached to a skull maxilla and the separation lines on the separating tool guidance contour displayed with optic enhancement;

[0031] FIG. 4 an isometric representation of the 3D model of the existing condition shown in FIG. 3 after performance of a partial cut in the maxilla along the separating tool guidance contour made by a separating tool, followed by removal of the bone joining implant from the 3D model of the existing condition;

[0032] FIG. 5 an isometric representation of the 3D model of the existing condition after performance of a complete cut of the maxilla along the previously partially formed separating lines, with optic enhancement of a separation line;

[0033] FIG. 6 an isometric representation of the 3D model of the existing condition with both previously separated maxilla bone sections prior to re-attachment of the bone joining implant;

[0034] FIG. 7 an isometric representation of the 3D model of the existing condition with the bone joining implant re-attached, where the first and third attachment areas are attached again to the first bone section, while the second attachment area is still distanced from the second bone section;

[0035] FIG. 8 a view from underneath the 3D model of the existing condition, showing the skull from underneath, with the second bone section being moved along the moving arrows in relation to the first bone section until the second bone section fits with the second attachment area.

[0036] FIG. 9 an isometric representation of the 3D model of the existing condition with a fully attached bone joining implant, firmly attached in both the first and the third, as well as the second attachment areas, to the first and second bone section, respectively, and

[0037] FIG. 10 an additional design with a wave or zigzag formation of the underside of an upper bridge.

[0038] Those figures are solely schematic in nature and are exclusively designed for a better understanding of the invention. Identical elements are marked with the identical reference.

[0039] In FIG. 1, a bone joining implant 1 is displayed particularly well, based on the invention, in accordance with a preferred design example. That figure displays a first attachment area 6, showing several holes for receiving fastening elements 5a, prepared for attachment to a first bone section 2 of a mammal bone 4, as well as a second attachment area 7, linked to the first attachment area 6. The second attachment area 7 also displays several holes for receiving fastening elements, hereafter referred to as the second holes for receiving fastening elements 5b, thus preparing the second attachment area 7 for attachment of a second bone section 3 of the mammal bone 4.

[0040] Clearly visible in FIG. 2 is the second attachment area 7, essentially formed by a principal bridge 22, also linked to a third attachment area 16. The second holes for fastening elements 5b are placed side by side in a chainlike manner on the principal bridge 22. As described below, the principal bridge 22 again forms a second and fourth bridge

11, 13. The third attachment area 16 is essentially formed similarly to the first attachment area 6, also displaying several holes for fastening elements that are hereafter referred to as the third set of holes for receiving fastening elements 5c. As described below in more detail, this third set of holes for receiving fastening elements 5c is designed for the attachment to the first bone section 2. The first attachment area 6 as well as the third attachment area 16 each display two groups of first and third holes for receiving fastening elements 5a, 5c, respectively, placed in a triangular formation relative to each other.

[0041] The first set of holes for receiving fastening elements 5a is placed on a first bridge 10, assigned to the first attachment area 6, essentially placed horizontally, attached to the mammal bone 4. Thus, the first attachment area 6 forms the first bridge 10, with a bar shaped design and linking both groups comprising the first set of holes for receiving fastening elements 5a (each with three first holes for receiving fastening elements) to each other. Two bridges 21, with an essentially vertical position relative to the first bridge 10, are then also linked with the first attachment area 6. Each of the bridges 21 is fitted to the first attachment area 6 within the area of a hole for fastening elements 5a. The bridges 21 are linking the first attachment area 6 or the first bridge 10 to the second bridge 11, also bar shaped and formed at the second attachment area 7, essentially running parallel to the first bridge 10. Both bridges 21 as well as the second bridge 11 associated with the second attachment area 7, together with the first bridge 10 associated with the first attachment area 6, essentially form a diamond shaped/rectangular frame structure 15a.

[0042] Similarly, the third attachment area 16 is linked to the second attachment area 7. The third set of holes for fastening elements 5c is placed on a third bridge 12, allocated to a third attachment area 16, essentially placed in a horizontal position, attached to the mammal bone 4. Thus, the third attachment area 16 forms the third bridge 12, bar shaped, and linking both groups

of the third set of holes for fastening elements 5c (each with three holes for receiving fastening elements of the third set 5c) to each other. Two bridges 21, with an essentially vertical position relative to the third bridge 12, are then also linked with the third attachment area 16. Each of the bridges 21 is fitted to the third attachment area 16 within the area of a hole for fastening elements 5c. The bridges 21 are linking the third attachment area 16 or the third bridge 12 to the fourth bridge 13, also bar shaped and formed at the second attachment area 7, essentially running parallel to the third bridge 12. Both bridges 21 as well as the fourth bridge 13 associated with the second attachment area 7, together with the third bridge 12 associated with the third attachment area 16, essentially form a second diamond shaped/rectangular frame structure 15b.

[0043] In this design, the first frame structure 15a varies slightly from the second frame structure 15b. The second frame structure 15b is formed differently in so far as the distance between the third and fourth bridge 12, 13 is greater than the distance between the first and second bridge 10, 11.

[0044] The third set of holes for fastening elements is formed similarly to the first and second set of holes for fastening elements 5a, 5b. The holes for receiving fastening elements 5a, 5b, 5c all provide reception for fastening elements in the usual manner, shaped as bone screws, with each of the holes for fastening elements 5a, 5b, 5c displaying a conic screw head fitting area 20 on the side facing away from the bone sections 2, 3, respectively. With the bone joining implant 1 attached to both bone sections 2, 3, the screw heads of the bone screws will then be completely sunk into the holes for fastening elements 5a, 5b, 5c.

[0045] As clearly shown by the interaction of FIGS. 1 and 2, the attachment areas 6, 7, 16 as well as a separating tool guidance contour 9, 18 placed on the respective frame structure 15a, 15b are formed from the same substance or integrally with each other.

[0046] In this design, an interior edge, namely, a first interior edge 14a of the first bridge 10, directly forms a first separating tool guidance contour 9 prepared to serve as a guiding track for a separating tool, namely, a sawing tool/buzz saw. The first separating tool guidance contour 9 remodels a first separating line 8 to be created, in the mammal bone 4. Alternatively or additionally, it is possible to design the (second) interior edge 14b of the second bridge 11 as a first separating tool guidance contour 9. The first and second interior edges 14a, 14b, respectively, are the lateral edges of the bridges 10, 11, facing each other.

[0047] In addition, the (third) interior edge 14c of the third bridge 12 is also designed as a separating tool guidance contour, that is as the second separating tool guidance contour 18. The second separating tool guidance contour 18 is here also used as a guiding track for a separating tool, namely a sawing tool/buzz saw for separating the first bone section 2 from the second bone section 3. The second separating tool guidance contour 18 remodels a first separating line 17 to be created, in the mammal bone 4. Alternatively or additionally, it is possible to design the (fourth) interior edge 14d of the fourth bridge 13 as a second separating tool guidance contour 18. The third and fourth interior edges 14c, 14d, respectively, are the lateral edges of the bridges 10, 11, facing each other.

[0048] The second and fourth bridges 10, 11 are also an integral component of the principal bridge 22 linking both frame structures 15a, 15b in a dimensionally stable, wing shaped position. It should be pointed out that the principal bridge 22, based on another design, located in a median position between the frame structures 15a, 15b, is provided with a resealing mechanism, so that the frame structures 15a, 15b can be attached to bone sections 2, 3 independently from each other and can then again be linked to each other through that mechanism in a dimensionally stable position.

[0049] Through its design as an implant, the bone joining implant is formed/made from a biocompatible substance, namely a hardened titanium substance. In addition or alternatively, the bone joining implant 1 can be manufactured, in whole or in part, from a biodegradable substance/be biodegradable.

[0050] In connection with FIG. 3 through 9, a procedure for manufacturing the bone implant, based on the invention, is very well displayed. For that purpose, as shown for example in FIG. 3, a 3D model of the existing condition of the mammal bone 4—designed here as a human skull—that is to be treated by osteotomy will be made. This is done by a tomographic imaging procedure (CT procedure), scanning the mammal bone 4 and establishing a first set of data containing/reflecting the three dimensional form of the mammal bone 4.

[0051] This mammal bone 4 already shows a malformation of a maxilla/maxilla bone 19 that is to be remedied by dysgnathic, separation surgery/osteotomy treatment. Based on this imaginary 3D model of the existing condition, a 3D target model of the maxilla/the mammal bone 4 will then be created, defining a cutting line 8 or 17, respectively, on the imaginary 3D model of the existing condition for each of the first and third attachment areas 6, 16. The cutting lines 8, 17, placed on the 3D model of the existing condition, are then each assigned one of the separating tool guidance contours 9, 18; that is, they will each be fitted to one of the separating tool guidance contours 9, 18 in accordance with the cutting lines 8, 17. After establishing those two cutting lines 8, 17, an imaginary separation of bone sections 2, 3 will be performed and they will be moved to the desired relative position, in relation to each other, eventually creating an imaginary 3D target model (calculated in a second data set) in FIG. 9, thus adjusting the attachment areas 6, 7, 16 to the shape of the 3D target model. Attachment areas 6, 7, 16 are adjusted and shaped in relation to each other in a way that will adjust the first and third attachment areas 6, 16 for a laminar fitting with the first bone section 2, and of the second attachment area 7 for a laminar fitting with the second bone section 2.

[0052] Also, in connection with FIG. 3 through 9, a treatment for the mammal bone 4/skull is very well displayed. For that purpose, the existing bone joining implant 1, using the first and third attachment areas 6, 16, is attached to the mammal bone 4, while the second attachment area 7 is still separated from the second bone section 3 of the maxilla (FIG. 3). Then, along the cutting lines 8, 17, formed by the separating tool guidance contours 9 and 18, the two bone sections 2, 3 will be partially separated within the frame structures 15a and 15b, as shown in the detailed illustrations in FIG. 1. After that, in accordance with FIG. 4, the bone joining implant 1 will be separated and removed from the first bone section 2 and the first bone section 2, in accordance with FIG. 5, will be completely separated from the second bone section 3 by additional sawing along the defined cutting line 8, 17. After complete separation of the bones sections 2 and 3, the bone joining implant 1 will be re-attached with the first and the first attachment area 16 to the first bone section 2 (FIG. 6), inserting a bone screw into each of the holes for fastening elements 5a, 5c, that will also be screwed into the first bone section 2. When both attachment areas 6 and 16 are attached to the first bone section 2 according to FIG. 7, the second bone section 3, separated from the first bone section, is moved according to FIG. 8 in relation to the first bone section 2 until the second bone section fits, according to FIG. 9, with the second attachment area 7, in particular within the area of the second set of holes for fastening elements 5b. In this desired, corrected position between the first and second bone sections 2, 3, several bone screws will then be inserted into the second set of holes for fastening elements 5b, and screwed into the second bone section 3. Ultimately, this resulted in both bone sections 2, 3 being firmly attached to each other by means of the bone joining implant 1.

[0053] In other words, the concept of the invention is to join a sawing template with a patient-specific orthognatic implant

to create a combination sawing and positioning implant. It is particularly beneficial that any poisoning aids such as splints, navigation devices, marking screws and milling lines can be eliminated. No additional drilling template is required. In addition, precision of the planned implementation and surgical intervention will be enhanced, which in turn alleviates bacterial exposure by eliminating any additional potential germ carriers. The surgical procedure will be facilitated by reducing the individual steps of surgical intervention. Also, the operating time will be reduced by eliminating any additional exchange of instruments and by reduction of the individual steps. This will ultimately provide for a more cost efficient production due to reduction of production steps.

[0054] Based on the invention, the design of the bone joining implant 1 comprises two bridges per side, horizontally aligned (10, 11; 12, 13), located in the right and left maxillary sinus wall, respectively, extending from the crista zygomaticoalveolaris to each lateral side of the foramen piriformis. Those two bridges (10, 11; 12, 13), through the in between space/slot thus created, form a guidance that corresponds to a sawing template. The in between space can also run parallel if a bone resection is to be performed. In that case, the lower edge (14a; 14c) of the upper bridge, and the upper edge of the lower bridge (14b; 14d) will serve as a guidance for the osteotomy. If necessary, drilling holes may be placed on the bridges (10, 11; 12, 13) in order to create additional fixation points. The horizontally aligned bridges (10, 11; 12, 13) are attached to four vertically aligned bridges 21, representing a link between the upper and lower pair of bridges (10, 11; 12, 13). The intended shifting information will be encrypted in this area by bending. Both horizontally aligned bridges (10, 11; 12, 13) on the left and right are each linked, in the outer (lateral) area, to a vertical bridge 21, to obtain sufficient stability in this area. If necessary, they can be elongated towards the cheek bone in order to obtain additional fixation points with osteosynthesis screws (bone screws). In a paranasal position on both sides, there are vertically aligned bridges with drilling holes for additional fixation. Below the spina nasales, the right and left sides are linked by a horizontally aligned bridge (10, 11; 12, 13). This link may also be created in situ in the spina nasales area by anchoring or using the lock and key model during surgery so that a large implant can initially be disassembled into smaller individual parts. This type of implant may also be provided for several jaw sections, such as the three part LeFort I osteotomy.

[0055] While FIG. 10 is only a representation of the wavy underside of a bridge 10, several such geometrically alternating structures may exist, particularly in those areas used as a separating tool guidance contour 9, the advantage being a reduction of the fitting area for the tool used for bone separation, such as a saw blade. A further thought is that it would make sense to be able to separate the “saw guiding area” after performing the sawing cut, possibly by nipping it off, similarly to a ‘Revell building set”, in order to reduce material input. Then the form could also be shaped like a guidance slot where, for instance, an oscillating knife could be guided. The “fastening bar” could have a “wavy shape”, at least on one side, possibly on two sides in order to minimize the contact area with the saw blade.

LIST OF REFERENCES

[0056] 1 Bone joining implant [0057] 2 First bone section [0058] 3 Second bone section [0059] 4 Mammal bone [0060] 5a First hole for fastening elements [0061] 5b Second hole for fastening elements [0062] 5c Third hole for fastening elements [0063] 6 First attachment area [0064] 7 Second attachment area [0065] 8 First cutting line [0066] 9 First separating tool guidance contour [0067] 10 First bridge [0068] 11 Second bridge [0069] 12 Third bridge [0070] 13 Fourth bridge [0071] 14a First interior edge [0072] 14b Second interior edge [0073] 14c Third interior edge [0074] 14d Fourth interior edge [0075] 15a First frame structure [0076] 15b Second frame structure [0077] 16 Third attachment area [0078] 17 Second cutting line [0079] 18 Second separating tool guidance contour [0080] 19 Maxilla bone [0081] 20 Screw head fitting area [0082] 21 Bridging bar [0083] 22 Principal bar