WO1987004917A1 - Endoprosthesis for the articular disk of the human temporo-mandibular joint - Google Patents

Endoprosthesis for the articular disk of the human temporo-mandibular joint Download PDF

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Publication number
WO1987004917A1
WO1987004917A1 PCT/EP1987/000095 EP8700095W WO8704917A1 WO 1987004917 A1 WO1987004917 A1 WO 1987004917A1 EP 8700095 W EP8700095 W EP 8700095W WO 8704917 A1 WO8704917 A1 WO 8704917A1
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Prior art keywords
disc
joint
curvature
radius
endoprosthesis according
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PCT/EP1987/000095
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German (de)
French (fr)
Inventor
Dietmar Kubein-Meesenburg
Hans-Georg Luhr
Hans NÄGERL
Original Assignee
Kubein Meesenburg Dietmar
Luhr Hans Georg
Naegerl Hans
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Application filed by Kubein Meesenburg Dietmar, Luhr Hans Georg, Naegerl Hans filed Critical Kubein Meesenburg Dietmar
Publication of WO1987004917A1 publication Critical patent/WO1987004917A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30988—Other joints not covered by any of the groups A61F2/32 - A61F2/4425
    • A61F2/3099—Other joints not covered by any of the groups A61F2/32 - A61F2/4425 for temporo-mandibular [TM, TMJ] joints
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30108—Shapes
    • A61F2002/3011—Cross-sections or two-dimensional shapes
    • A61F2002/30112—Rounded shapes, e.g. with rounded corners
    • A61F2002/30125—Rounded shapes, e.g. with rounded corners elliptical or oval
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30721—Accessories
    • A61F2002/30754—Implants for interposition between two natural articular surfaces
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2230/00—Geometry of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2230/0002—Two-dimensional shapes, e.g. cross-sections
    • A61F2230/0004—Rounded shapes, e.g. with rounded corners
    • A61F2230/0008—Rounded shapes, e.g. with rounded corners elliptical or oval

Definitions

  • the present invention relates to an endoprosthesis for the joint disc of the temporomandibular joint.
  • Endoprostheses for the temporomandibular joint are already known, see DE-PS 21 02 454 and US Pat. No. 3,178,728, which are used when the joint disc of the temporomandibular joint has to be removed due to injury or illness.
  • These known endoprostheses are partial endoprostheses that are attached to the zygomatic bone and can be inserted into the socket of the temporomandibular joint with a correspondingly contoured section. Due to the rigid connection to the zygomatic bone, these endoprostheses are not suitable for simulating the joint function of the healthy joint, which is a double joint, with the condyle (joint head) performing a rotational movement and a linear movement.
  • the invention has for its object to provide an endoprosthesis for the joint disk of the temporomandibular joint in the event of failure, which largely ensures the natural joint function and which is permanent and the occurrence avoids side effects in the human body.
  • the endoprosthesis is formed from a disk-shaped body which is approximately elliptical in outline from a material with a greater surface hardness than that of the bones of the temporomandibular joint, the disk-shaped body being seen in cross-section to its longer axis XX in each case an upper and a has lower concavely curved surface and the radii of curvature of the two surfaces are so different that that the upper surface is larger than that of the lower.
  • the invention is based on the knowledge that the shape according to the invention makes it possible to maintain the natural joint function without the need for a muscular connection as with the natural temporomandibular joint.
  • the endoprosthesis according to the invention surrounds the condyle in a cap-like manner, with overemphasized enlarged ridges ensuring the functional stability of the artificial disc, so that pathological sliding of the disc cannot occur.
  • the design of the artificial disc as a double concave disc, with the concave surfaces having a constant or changing radius of curvature parallel to the smaller axis of the ellipse, is surprising for the person skilled in the art, since this differs fundamentally from the natural design, in which the flexible disc is flexible due to its flexibility has a changing surface shape during the movement of the temporomandibular joint, the shape of which can be described by means of chain line functions. Deviating from this, a constant radius of curvature or changing radius of curvature is provided according to the invention.
  • the natural two-chamber joint is changed into a single-chamber joint by the endoprosthesis according to the invention.
  • the hardness of the surface of the disc according to the invention is greater than the hardness of the bones of the temporomandibular joint. This ensures permanent function without any adverse side effects, since during the adjustment phase in the joint on the bones of the same (due to necrosis), sharp burrs form which would have a cutting effect on a soft material of the disc. These chips would lead to foreign body granuloma trousers. The invention avoids this danger. Further advantageous embodiments of the invention are contained in the subclaims.
  • FIG. 2 is a perspective view of a joint disc according to the invention from the top
  • FIG. 3 is a perspective view of a joint disc according to the invention from the bottom view
  • FIG. 5 shows a frontal section along the section line VV in FIG. 2.
  • a human temporomandibular joint from an articular socket 1 (temporal bone) and a joint head 2 (condyle) of the lower jaw and a joint disc 3 (discus) inserted between them is shown in section according to the invention.
  • the precise configuration of the joint disk 3 according to the invention is shown in FIGS. 2 to 5.
  • the joint disk 3 has an essentially elliptical circumferential contour, the longer ellipse axis XX in FIG. 1 running perpendicular to the plane of the drawing and the short ellipse axis YY being identified.
  • the joint disc 3 consists of a body-compatible material that has a higher surface hardness than the bones of the temporomandibular joint.
  • Corrosion-resistant metals and metal alloys such as, for example, titanium and chromium cobalt molybdenum or ceramic materials or metal-ceramic materials are particularly suitable as materials.
  • plastics with corresponding properties can also be used.
  • the joint disc 3 has two concavely curved surfaces 4 and 5, namely the upper surface 4 facing the joint socket and the surface 5 facing the joint head 2.
  • the sagittal radius of curvature of the surface 4 corresponds to the radius of curvature of the os Temporale is designated by r o ⁇ and that of surface 5 corresponding to that of the condyle by r ⁇ .
  • the thickness of the joint disk 3 in the area of the minimum disc strength is d.
  • r is the radius of curvature of the joint path (axisiography) of the temporomandibular joint.
  • the joint disc according to the invention can be determined.
  • the therapeutically necessary achsiographic curvature is linked to the coupling formula of the anterior and posterior curvature for a given occlusion, depending on the relationship
  • ⁇ is the initial angle of inclination to the functional level and "a" can have an individually constant value from 1 to 6; see also European patent application 861162204.
  • ⁇ varies in a frontal direction on the eminentia.
  • r ⁇ , r o ⁇ can be determined by computer tomographic recordings.
  • d d ( ⁇ ) and must satisfy the above relationship.
  • the necessary and therapeutically desired curvature of the joint disc according to the invention must be calculated and produced in every layer depth .
  • surface 4 is slightly convexly curved in the direction of the larger axis X-X, while surface 5 is concavely curved in this direction.
  • r is the radius of curvature of the axisiography of the temporomandibular joint
  • r o ⁇ 1 is the radius of curvature of the temporal bone and the surface 4 facing it
  • r ⁇ 1 is the radius of curvature of the condyle and the surface facing it
  • d 1 is the thickness of the joint disc on a specific one Point of the joint disc.
  • the joint disk according to the invention has an edge bead 6, the outside 7 of which is convexly curved. Due to the fact that the artificial disc is about 1 - 2 mm longer in the frontal and sagittal direction, the edge bead is increased. This relative reinforcement of the edge bead fixes the disc without additional suspension.
  • the condyle 2 can, as in the healthy temporomandibular joint, perform a rotational movement around the temporal bone and the condyle.
  • the rotational movements take place around the axes RK and ROT.
  • the correspondingly assigned articular surface of the temporal bone is surface 4, which is concavely curved with the radius r o ⁇ .
  • the movement of the condyle 2 takes place along the temporal bone 1 in the direction of the arrow B.
  • the joint disk 3 slides on its surfaces 4 and 5; the surface 5 is also concavely curved, namely with the radius r ⁇ .
  • the appropriate joint surface is thus provided for each movement, so that the loads that occur are distributed over two joint surfaces.
  • the joint disc 3 lies over the entire surface on the adjacent joint surfaces of the TMJ bones, so that pressure loads are absorbed over the entire surface. Point contacts between the condyle 2 and the temporal bone 1 do not occur.
  • the joint disk 3 according to the invention therefore takes on the full function of the natural disc present in the temporomandibular joint.
  • the natural disc is held in the joint space, ie in the space between the condyle 2 and the temporal bone 1 by elastic bands and muscles.
  • the connection of the joint disc according to the invention to these ligaments and muscles is not necessary, and yet it can sufficiently fulfill the required joint function.
  • the joint disc according to the invention is slightly enlarged compared to the natural disc, which also increases the edge bead 6, it is ensured that the condyle 2 does not leave the joint disc during its movements.
  • the joint disc according to the invention which rests in a cap-like manner on the condyle, is carried along. This movement of the joint disc corresponds to the natural movement of the disc.
  • the synovial disc is completely flushed with synovial fluid, which results in a natural optimal lubrication of the joint and the disc replacement.

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  • Health & Medical Sciences (AREA)
  • Plastic & Reconstructive Surgery (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Cardiology (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Transplantation (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Vascular Medicine (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Prostheses (AREA)

Abstract

The endoprosthesis for the articular disk or meniscus of the temporo-mandibular joint comprises a disk-shaped body (3) with an elliptical contour and comprised of a material of which the surface is harder than that the of the bones of the temporo-mandibular joint. The cross-section of the disk-shaped body (3), viewed in the direction of its longer axis X-X, comprises a top and a bottom concave surfaces. The curvature radii rK and rOT of both surfaces (4 and 5) are different so that the curvature radius rOT of the top surface (4) is bigger than the curvature radius rK of the bottom surface (5).

Description

Endoprothese für die Gelenkscheibe des menschlichen KiefergelenksEndoprosthesis for the joint disk of the human temporomandibular joint
Die vorliegende Erfindung betrifft eine Endoprothese für die Gelenkscheibe des Kiefergelenks.The present invention relates to an endoprosthesis for the joint disc of the temporomandibular joint.
Es sind bereits Endoprothesen für das Kiefergelenk bekannt, siehe DE-PS 21 02 454 und US-PS 3,178,728, die Verwendung finden, wenn die Gelenkscheibe des Kiefergelenks aufgrund von Verletzung oder Krankheit entfernt werden muß. Bei diesen bekannten Endoprothesen handelt es sich um Teilendoprothesen, die am Jochbein befestigt werden und mit einem entsprechend konturierten Abschnitt in die Gelenkpfanne des Kiefergelenks einsetzbar sind. Durch die starre Verbindung zum Jochbein sind diese Endoprothesen aber nicht dazu geeignet, die Gelenkfunktion des gesunden Gelenks nachzubilden, das ein Doppelgelenk ist, wobei vom Kondylus (Gelenkkopf) eine Rotationsbewegung und eine lineare Bewegung ausgeführt werden.Endoprostheses for the temporomandibular joint are already known, see DE-PS 21 02 454 and US Pat. No. 3,178,728, which are used when the joint disc of the temporomandibular joint has to be removed due to injury or illness. These known endoprostheses are partial endoprostheses that are attached to the zygomatic bone and can be inserted into the socket of the temporomandibular joint with a correspondingly contoured section. Due to the rigid connection to the zygomatic bone, these endoprostheses are not suitable for simulating the joint function of the healthy joint, which is a double joint, with the condyle (joint head) performing a rotational movement and a linear movement.
Der Erfindung liegt die Aufgabe zugrunde, eine Endoprothese für die Gelenkscheibe des Kiefergelenks bei Ausfall derselben zu schaffen, die die natürliche Gelenkfunktion weitestgehend sicherstellt und die dauerhaft ist und das Auftreten von Nebenwirkungen im menschlichen Körper vermeidet.The invention has for its object to provide an endoprosthesis for the joint disk of the temporomandibular joint in the event of failure, which largely ensures the natural joint function and which is permanent and the occurrence avoids side effects in the human body.
Erfindungsgemäß wird dies dadurch erreicht, daß die Endoprothese aus einem im Umriß etwa elliptischen scheibenförmigen Körper aus einem Material mit einer größeren Oberflächenhärte als der der Knochen des Kiefergelenks gebildet wird, wobei der scheibenförmige Körper im Querschnitt zu seiner längeren Achse X-X gesehen jeweils eine obere und eine untere konkav gekrümmte Oberfläche besitzt und die Krümmungsradien der beiden Oberflächen derart unterschiedlich sind, daß der der oberen Fläche größer ist als der der unteren.According to the invention, this is achieved in that the endoprosthesis is formed from a disk-shaped body which is approximately elliptical in outline from a material with a greater surface hardness than that of the bones of the temporomandibular joint, the disk-shaped body being seen in cross-section to its longer axis XX in each case an upper and a has lower concavely curved surface and the radii of curvature of the two surfaces are so different that that the upper surface is larger than that of the lower.
Die Erfindung basiert auf der Erkenntnis, daß es durch die erfindungsgemäße Formgebung möglich ist, die natürliche Gelenkfunktion zu erhalten, ohne daß hierzu eine muskelmäßige Anbindung wie beim natürlichen Kiefergelenk erforderlich ist. Die erfindungsgemäße Endoprothese umgibt kappenartig den Kondylus, wobei überbetonte vergrößerte Randwulste die Funktionsstabilität des künstlichen Diskus sicherstellen, so daß ein pathologisches Abgleiten des Diskus nicht auftreten kann. Die Ausbildung des künstlichen Diskus als Doppelkonkavscheibe, wobei die konkaven Oberflächen im Querschnitt parallel zur kleineren Ellipsenachse einen konstanten oder sich ändernden Krümmungsradius besitzen, ist für den Fachmann überraschend, da dies grundsätzlich von der natürlichen Ausbildung abweicht, bei der die Gelenkscheibe aufgrund ihrer Flexibilität eine sich während der Kiefergelenkbewegung verändernde Oberflächenform aufweist, deren Form mittels Kettenlinienfunktionen beschrieben werden kann. Davon abweichend ist erfindungsgemäß ein konstanter Krümmungsradius oder sich ändernder Krümmungsradius vorgesehen. Zudem wird durch die erfindungsgemäße Endoprothese das natürliche Zweikammergelenk in ein Einkammergelenk verändert. Erfindungswesentlich ist weiterhin, daß die Härte der Oberfläche des erfindungsgemäßen Diskus größer ist als die Härte der Knochen des Kiefergelenks. Denn hierdurch wird eine dauerhafte Funktion ohne nachteilige Nebenwirkung gewährleistet, da während der Anpassungsphase im Gelenk an den Knochen desselben (bedingt durch Nekrosen) sich scharfe Grate ausbilden, die bei einem weichen Material des Diskus spanabhebend wirken würden. Diese Späne würden zu Fremdkörpergranulomathosen führen. Die Erfindung vermeidet diese Gefahr. Weitere vorteilhafte Ausführungen der Erfindung sind in den Unteransprüchen enthalten.The invention is based on the knowledge that the shape according to the invention makes it possible to maintain the natural joint function without the need for a muscular connection as with the natural temporomandibular joint. The endoprosthesis according to the invention surrounds the condyle in a cap-like manner, with overemphasized enlarged ridges ensuring the functional stability of the artificial disc, so that pathological sliding of the disc cannot occur. The design of the artificial disc as a double concave disc, with the concave surfaces having a constant or changing radius of curvature parallel to the smaller axis of the ellipse, is surprising for the person skilled in the art, since this differs fundamentally from the natural design, in which the flexible disc is flexible due to its flexibility has a changing surface shape during the movement of the temporomandibular joint, the shape of which can be described by means of chain line functions. Deviating from this, a constant radius of curvature or changing radius of curvature is provided according to the invention. In addition, the natural two-chamber joint is changed into a single-chamber joint by the endoprosthesis according to the invention. It is also essential to the invention that the hardness of the surface of the disc according to the invention is greater than the hardness of the bones of the temporomandibular joint. This ensures permanent function without any adverse side effects, since during the adjustment phase in the joint on the bones of the same (due to necrosis), sharp burrs form which would have a cutting effect on a soft material of the disc. These chips would lead to foreign body granuloma trousers. The invention avoids this danger. Further advantageous embodiments of the invention are contained in the subclaims.
Anhand des in den beiliegenden Zeichnungen dargestellten Ausführungsbeispiels wird die Erfindung näher erläutert. Es zeigen:The invention is explained in more detail with reference to the exemplary embodiment illustrated in the accompanying drawings. Show it:
Fig. 1 einen Schnitt durch ein Kiefergelenk mit eingesetzter erfindungsgemäßer Gelenkscheibe,1 shows a section through a temporomandibular joint with an inventive joint disk inserted,
Fig. 2 eine perspektivische Ansicht einer erfindungsgemäßen Gelenkscheibe von der Oberseite her,2 is a perspective view of a joint disc according to the invention from the top,
Fig. 3 eine perspektivische Ansicht einer erfindungsgemäßen Gelenkscheibe von der Unteransicht her,3 is a perspective view of a joint disc according to the invention from the bottom view,
Fig. 4 einen sagittalen Schnitt entlang der Schnittlinie IV-IV in Fig. 2,4 shows a sagittal section along the section line IV-IV in FIG. 2,
Fig. 5 einen frontalen Schnitt entlang der Schnittlinie V-V in Fig. 2. In Fig. 1 ist ein menschliches Kiefergelenk aus einer Gelenkpfanne 1 (Os temporale) und einem Gelenkkopf 2 (Kondylus) des Unterkiefers und einer zwischen diesen eingesetzten Gelenkscheibe 3 (Diskus) gemäß der Erfindung im Schnitt dargestellt. Die genaue Ausgestaltung der erfindungsgemäßen Gelenkscheibe 3 ergibt sich aus den Fig. 2 bis 5. Die Gelenkscheibe 3 hat eine im wesentlichen elliptische Umfangskontur, wobei die längere Ellipsenachse X-X in Fig. 1 senkrecht zur Zeichenebene verläuft und die kurze Ellipsenachse Y-Y gekennzeichnet ist. Die Gelenkscheibe 3 besteht aus einem körperverträglichen Material, das eine höhere Oberflächenhärte als die Knochen des Kiefergelenks besitzt. Als Materialien sind insbesondere korrosionsbeständige Metalle und Metallegierungen, wie z.B. Titan und Chromkobaltmolybdän oder Keramikmassen bzw. Metallkeramikmassen geeignet. Jedoch können auch Kunststoffe mit entsprechenden Eigenschaften verwendet werden.5 shows a frontal section along the section line VV in FIG. 2. In Fig. 1, a human temporomandibular joint from an articular socket 1 (temporal bone) and a joint head 2 (condyle) of the lower jaw and a joint disc 3 (discus) inserted between them is shown in section according to the invention. The precise configuration of the joint disk 3 according to the invention is shown in FIGS. 2 to 5. The joint disk 3 has an essentially elliptical circumferential contour, the longer ellipse axis XX in FIG. 1 running perpendicular to the plane of the drawing and the short ellipse axis YY being identified. The joint disc 3 consists of a body-compatible material that has a higher surface hardness than the bones of the temporomandibular joint. Corrosion-resistant metals and metal alloys, such as, for example, titanium and chromium cobalt molybdenum or ceramic materials or metal-ceramic materials are particularly suitable as materials. However, plastics with corresponding properties can also be used.
Wie Fig. 3 zeigt, besitzt die erfindungsgemäße Gelenkscheibe 3 zwei konkav gebogene Oberflächen 4 und 5, und zwar die obere, der Gelenkpfanne zugekehrte Oberfläche 4, und die dem Gelenkkopf 2 zugekehrte Oberfläche 5. Der sagittale Krümmungsradius der Oberfläche 4 entsprechend dem Krümmungsradius des Os temporale ist mit roτ und der der Oberfläche 5 entsprechend dem des Kondylus mit rκ bezeichnet. Die Dicke der Gelenkscheibe 3 im Bereich der minimalen Diskusstärke ist d. Die Krümmungsradien rκ und roτ genügen der folgenden Formel r = rκ + roτ + d.As shown in FIG. 3, the joint disc 3 according to the invention has two concavely curved surfaces 4 and 5, namely the upper surface 4 facing the joint socket and the surface 5 facing the joint head 2. The sagittal radius of curvature of the surface 4 corresponds to the radius of curvature of the os Temporale is designated by r oτ and that of surface 5 corresponding to that of the condyle by r κ . The thickness of the joint disk 3 in the area of the minimum disc strength is d. The radii of curvature r κ and r oτ satisfy the following formula r = r κ + r oτ + d.
Hierbei ist r der Krümmungsradius der Gelenkbahn (Achsiographie) des Kiefergelenks.Here r is the radius of curvature of the joint path (axisiography) of the temporomandibular joint.
Aus den vorhandenen anatomischen Parametern, z. B. rκ und roτ oder d, die computertomographisch transversal (Achse X- X) und sagittal (Achse Y-Y) aus dem Kiefergelenkbereich entnommen werden, und eventuell zusätzlich notwendigen Parametern aus einer auch eventuell pathologisch veränderten Achsiographie kann die Bestimmung der erfindungsgemäßen Gelenkscheibe erfolgen. Zudem ist die therapeutisch notwendige achsiographische Krümmung an die Koppelformel der anterioren und posterioren Krümmung bei gegebener Okklusion gebunden, entsprechend der BeziehungFrom the existing anatomical parameters, e.g. B. r κ and r oτ or d, which is transverse to computed tomography (axis X- X) and sagittal (axis YY) from the temporomandibular joint area, and any additional parameters that may be necessary from an axiography that may also be pathologically changed, the joint disc according to the invention can be determined. In addition, the therapeutically necessary achsiographic curvature is linked to the coupling formula of the anterior and posterior curvature for a given occlusion, depending on the relationship
Figure imgf000007_0001
wobei α der initiale Neigungswinkel zur Funktionsebene ist und "a" einen individuell konstanten Wert von 1 bis 6 besitzen kann; siehe hierzu auch die europäische Patentanmeldung 861162204.
Figure imgf000007_0001
where α is the initial angle of inclination to the functional level and "a" can have an individually constant value from 1 to 6; see also European patent application 861162204.
α variiert in frontaler Richtung auf der Eminentia. rκ, roτ sind durch computertomographische Aufnahmen bestimmbar. d = d (α) und muß vorstehende Beziehung erfüllen.α varies in a frontal direction on the eminentia. r κ , r oτ can be determined by computer tomographic recordings. d = d (α) and must satisfy the above relationship.
Ausgehend von dem jeweils individuellen Faktor a der okklusalen Morphologie ist somit in Kombination mit den abgegriffenen anatomischen Parametern rκ, roτ oder d die notwendige und therapeutisch gewünschte Kurvatur der erfindungsgemäßen Gelenkscheibe in jeder Schichttiefe zu berechnen und herzustellen.On the basis of the individual factor a of the occlusal morphology in combination with the anatomical parameters r κ , r oτ or d, the necessary and therapeutically desired curvature of the joint disc according to the invention must be calculated and produced in every layer depth .
Wie sich aus Fig. 5 ergibt, ist die Oberfläche 4 in Richtung der größeren Achse X-X leicht konvex gekrümmt, während die Oberfläche 5 in dieser Richtung konkav gekrümmt verläuft.5, surface 4 is slightly convexly curved in the direction of the larger axis X-X, while surface 5 is concavely curved in this direction.
Hierbei gilt die Beziehung r = roτ1 + rκ1 + d1. Hierbei ist r der Krümmungsradius der Achsiographie des Kiefergelenks, roτ1 ist der Krümmungsradius des Os temporale und der diesem zugekehrten Oberfläche 4, und rκ1 ist der Krümmungsradius des Kondylus und der ihm zugekehrten Oberfläche, und d1 ist die Dicke der Gelenkscheibe an einem bestimmten Punkt der Gelenkscheibe.The relationship r = r oτ1 + r κ1 + d 1 applies here . Here r is the radius of curvature of the axisiography of the temporomandibular joint, r oτ1 is the radius of curvature of the temporal bone and the surface 4 facing it, and r κ1 is the radius of curvature of the condyle and the surface facing it, and d 1 is the thickness of the joint disc on a specific one Point of the joint disc.
Wie sich insbesondere aus den Fig. 4 und 5 ergibt, weist die erfindungsgemäße Gelenkscheibe einen Randwulst 6 auf, dessen Außenseite 7 konvex gekrümmt ist. Dadurch, daß der künstliche Diskus eine etwa 1 - 2 mm größere Distanz in frontaler und sagittaler Richtung aufweist, wird der Randwulst erhöht. Durch diese relative Verstärkung der Randwulst wird der Diskus ohne zusätzliche Aufhängung fixiert.As can be seen in particular from FIGS. 4 and 5, the joint disk according to the invention has an edge bead 6, the outside 7 of which is convexly curved. Due to the fact that the artificial disc is about 1 - 2 mm longer in the frontal and sagittal direction, the edge bead is increased. This relative reinforcement of the edge bead fixes the disc without additional suspension.
Aufgrund der Erfindung kann der Kondylus 2, wie beim gesunden Kiefergelenk, eine Rotationsbewegung um das Os temporale und den Kondylus ausführen. Die Rotationsbewegungen erfolgen dabei um die Achsen RK und ROT. Die entsprechend zugeordnete Gelenkfläche des Os temporale ist die Oberfläche 4, die mit dem Radius roτ konkav gekrümmt verläuft. Die Bewegung des Kondylus 2 erfolgt längs des Os temporale 1 in Richtung des Pfeiles B. Die Geϊenkscheibe 3 gleitet dabei auf ihren Oberflächen 4 und 5; die Oberfläche 5 ist ebenfalls konkav gekrümmt, und zwar mit dem Radius rκ. Es ist somit für jede Bewegung die passende Gelenkfläche vorgesehen, so daß die auftretenden Belastungen auf zwei Gelenkflächen verteilt werden. Die Gelenkscheibe 3 liegt dabei vollflächig auf den angrenzenden Gelenkflächen der Kiefergelenkknochen auf, so daß Druckbelastungen über die gesamte Fläche verteilt aufgefangen werden. Punktförmige Kontakte zwischen dem Kondylus 2 und dem Os temporale 1 treten nicht auf. Die erfindungsgemäße Gelenkscheibe 3 übernimmt daher in vollem Umfange die Funktion des im Kiefergelenk vorhandenen natürlichen Diskus. Der natürliche Diskus wird im Gelenkspalt, d. h. im Zwischenraum zwischen dem Kondylus 2 und dem Os temporale 1 durch elastische Bänder und Muskeln gehalten. Der Anschluß der erfindungsgemäßen Gelenkscheibe an diese Bänder und Muskeln ist nicht erforderlich, und trotzdem kann diese die erforderliche Gelenkfunktion hinreichend erfüllen. Da die erfindungsgemäße Gelenkscheibe gegenüber dem natürlichen Diskus leicht vergrößert ausgebildet ist, was den Randwulst 6 ebenfalls vergrößert, wird sichergestellt, daß der Kondylus 2 bei seinen Bewegungen die Gelenkscheibe nicht verläßt. Bei Verschiebungen des Kondylus, d. h. bei prothrusiven Bewegungen des Unterkiefers, wird die kappenartig auf dem Kondylus aufliegende erfindungsgemäße Gelenkscheibe mitgeführt. Diese Bewegung der Gelenkscheibe entspricht dabei der natürlichen Bewegung des Diskus. Die Gelenkscheibe wird vollständig von Gelenkflüssigkeit umspült, wodurch eine natürliche optimale Schmierung des Gelenks und des Diskusersatzes erreicht ist. Due to the invention, the condyle 2 can, as in the healthy temporomandibular joint, perform a rotational movement around the temporal bone and the condyle. The rotational movements take place around the axes RK and ROT. The correspondingly assigned articular surface of the temporal bone is surface 4, which is concavely curved with the radius r oτ . The movement of the condyle 2 takes place along the temporal bone 1 in the direction of the arrow B. The joint disk 3 slides on its surfaces 4 and 5; the surface 5 is also concavely curved, namely with the radius r κ . The appropriate joint surface is thus provided for each movement, so that the loads that occur are distributed over two joint surfaces. The joint disc 3 lies over the entire surface on the adjacent joint surfaces of the TMJ bones, so that pressure loads are absorbed over the entire surface. Point contacts between the condyle 2 and the temporal bone 1 do not occur. The joint disk 3 according to the invention therefore takes on the full function of the natural disc present in the temporomandibular joint. The natural disc is held in the joint space, ie in the space between the condyle 2 and the temporal bone 1 by elastic bands and muscles. The connection of the joint disc according to the invention to these ligaments and muscles is not necessary, and yet it can sufficiently fulfill the required joint function. Since the joint disc according to the invention is slightly enlarged compared to the natural disc, which also increases the edge bead 6, it is ensured that the condyle 2 does not leave the joint disc during its movements. When the condyle is displaced, ie during prothrusive movements of the lower jaw, the joint disc according to the invention, which rests in a cap-like manner on the condyle, is carried along. This movement of the joint disc corresponds to the natural movement of the disc. The synovial disc is completely flushed with synovial fluid, which results in a natural optimal lubrication of the joint and the disc replacement.

Claims

A n s p r ü c h e Expectations
1. Endoprothese für die Gelenkscheibe des Kiefergelenks, g e k e n n z e i c h n e t d u r c h einen im Umriß etwa elliptischen scheibenförmigen Körper (3) aus einem Material mit einer größeren Oberflächenhärte als die der Knochen des Kiefergelenks, wobei der scheibenförmige Körper (3) im Querschnitt in seiner längeren Achse X-X gesehen jeweils eine obere und untere konkav gekrümmte Oberfläche besitzt und die Krümmungsradien rκ und roτ der beiden Oberflächen (4) und (5) derart unterschiedlich sind, daß der Krümmungsradius roτ der oberen Fläche (4) größer ist als der Krümmungsradius rκ der unteren Oberfläche (5).1. Endoprosthesis for the articular disc of the temporomandibular joint, characterized by a disc-shaped body (3) which is approximately elliptical in outline and made of a material with a greater surface hardness than that of the bones of the temporomandibular joint, the disc-shaped body (3) seen in cross section in its longer axis XX has an upper and lower concave curved surface and the radii of curvature r κ and r oτ of the two surfaces (4) and (5) are so different that the radius of curvature r oτ of the upper surface (4) is larger than the radius of curvature r κ of the lower one surface (5).
2. Endoprothese nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, daß die beiden Oberflächen (4) und (5) jeweils in einem umlaufenden Randwulst (6) auslaufen, dessen Höhe h größer ist als die Höhe der entsprechenden Randwulst der natürlichen Gelenkscheibe.2. Endoprosthesis according to claim 1, characterized in that the two surfaces (4) and (5) each end in a circumferential edge bead (6), the height h of which is greater than the height of the corresponding edge bead the natural joint disc.
3. Endoprothese nach Anspruch 2, d a d u r c h g e k e n n z e i c h n e t, daß die Höhe h des jeweiligen Randwulstes (6) durch eine mindestens 1 - 2 mm Durchmesservergrößerung der Gelenkscheibe gegenüber dem natürlichen Diskus erzeugt ist.3. Endoprosthesis according to claim 2, characterized in that the height h of the respective edge bead (6) is created by an increase in the diameter of the articular disc by at least 1 - 2 mm compared to the natural disc.
4. Endoprothese nach Anspruch 2 oder 3, d a d u r c h g e k e n n z e i c h n e t, daß der Randwulst (6) eine konvex gekrümmte Außenfläche4. Endoprosthesis according to claim 2 or 3, characterized in that the edge bead (6) has a convexly curved outer surface
(7) besitzt.(7) has.
5. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 4, d a d u r c h g e k e n n z e i c h n e t, daß die Krümmungsradien roτ und rκ der beiden Oberflächen (4,5) jeweils über die gesamte Länge der längeren Achse X-X konstant sind.5. Endoprosthesis according to one or more of claims 1 to 4, characterized in that the radii of curvature r oτ and r κ of the two surfaces (4,5) are each constant over the entire length of the longer axis XX.
6. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 5, d a d u r c h g e k e n n z e i c h n e t, daß die Krümmungsradien roτ und rκ die folgenden6. Endoprosthesis according to one or more of claims 1 to 5, characterized in that the radii of curvature r oτ and r κ are the following
Funktionen erfüllen:Perform functions:
1. r = rκ + roτ + d, wobei rκ = sagittaler Radius des1. r = r κ + r oτ + d, where r κ = sagittal radius of the
Kondylus ist, roτ = sagittaler Radius des Os temporale und d die Dicke der Gelenkscheibe im Bereich der minimalen Diskusstärke ist undCondyle is, r oτ = sagittal radius of the temporal bone and d is the thickness of the articular disc in the area of the minimum disc thickness and
2.
Figure imgf000011_0001
hierbei ist a der individuelle Faktor der okklusalen Morphologie mit Werten von 1 bis 6 und α ist der initiale Neigungswinkel zur Funktionsebene und r der Krümmungsradius der Gelenkbahn (Achsiographie).2.
Figure imgf000011_0001
Here a is the individual factor of the occlusal morphology with values from 1 to 6 and α is the initial angle of inclination to the functional plane and r is the radius of curvature of the joint path (axialiography).
7. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 6, d a d u r c h g e k e n n z e i c hn e t, daß der scheibenförmige Körper (3) starr ist.7. Endoprosthesis according to one or more of claims 1 to 6, characterized in that the disc-shaped body (3) is rigid.
8. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 7, d a d u r c h g e k e n n z e i c h n e t, daß der scheibenförmige Körper aus einem korrosionsbeständigen Metall, wie Titan oder Chromkobaltmolybdän besteht.8. Endoprosthesis according to one or more of claims 1 to 7, characterized in that the disc-shaped body consists of a corrosion-resistant metal, such as titanium or chromium cobalt molybdenum.
9. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 7, d a d u r c h g e k e nn z e i c h n e t, daß der scheibenförmige Körper (3) aus einer keramischen oder einer metallkeramischen Masse besteht.9. Endoprosthesis according to one or more of claims 1 to 7, so that the disc-shaped body (3) consists of a ceramic or a metal-ceramic mass.
10. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 7, d a d u r c h g e k e n n z e i c h n e t, daß der scheibenförmige Körper (3) aus einem Kunststoff gebildet ist.10. Endoprosthesis according to one or more of claims 1 to 7, so that the disc-shaped body (3) is made of a plastic.
11. Endoprothese nach einem oder mehreren der Ansprüche 1 bis 10, d a d u r c h g e k e n n z e i c h n e t, daß die Oberfläche des scheibenförmigen Körpers (3) in11. Endoprosthesis according to one or more of claims 1 to 10, so that the surface of the disc-shaped body (3) in
Richtung der größeren Ellipsenachse X-X, die dem Os temporale zugekehrt ist, leicht konvex mit einem Krümmungsradius roτ1 verläuft, und die dem Kondylus zugekehrte Oberfläche (4) in Richtung der längeren Achse X-X mit einem Krümmungsradius rκ1 konvex verläuft, wobei die folgende Beziehung gilt r = roτ1 + rκ1 + d1, wobei r der Krümmungsradius der Gelenkbahn ist und d1 die Dicke der Gelenkscheibe (3) an einem bestimmten Punkt der Gelenkscheibe. Direction of the larger ellipse axis XX, which corresponds to Os temporale, runs slightly convex with a radius of curvature r oτ1 , and the surface (4) facing the condyle runs convex in the direction of the longer axis XX with a radius of curvature r κ1 , whereby the following relationship applies r = r oτ1 + r κ1 + d 1 , where r is the radius of curvature of the joint path and d 1 is the thickness of the joint disk (3) at a certain point on the joint disk.
PCT/EP1987/000095 1986-02-22 1987-02-19 Endoprosthesis for the articular disk of the human temporo-mandibular joint WO1987004917A1 (en)

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DE19863605776 DE3605776A1 (en) 1986-02-22 1986-02-22 PROSTHESIS FOR THE JOINTS OF THE HUMAN BODY, WHOSE SITTING IN THE JOINT GAP cartilage discs (DISCUS)
DEP3605776.2 1986-02-22

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DE3908958A1 (en) * 1989-03-18 1990-09-20 Kubein Meesenburg Dietmar ARTIFICIAL JOINT
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US5405393A (en) * 1993-06-02 1995-04-11 Academisch Ziekenhuis Groningen Temporomandibular joint prosthesis
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CN114748215A (en) * 2022-03-30 2022-07-15 上海市口腔医院(上海市口腔健康中心) 3D prints bionical human temporomandibular joint dish

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