Temporarily fixable osteosynthesis device for vertebrae with rotatable fixation element

Abstract

Osteosynthesis device (1) for treating the spinal column, consisting of a fork head (10) which is U-shaped in a side view and has a through-opening (18) and which, in the proximal direction (101), has two fork limbs (11, 12) with an internal thread (16), and in which a connecting rod (50) can be received, and a ball-head receiving region (19) is provided in the fork head (10) in the distal direction (102) in the through-opening (18), and a bone anchor (90) is mounted pivotably therein, characterized in that there is provided on the fork head (10) a transverse opening (13) which communicates (185) with the through-opening of the fork head (10), and a fixing element (30) is mounted in this transverse opening (13) so as to be rotatable about a transverse-opening axis (130), and the fixing element (30), with introduction of a torsional moment about the transverse-opening axis (130), clamps the head region (91) of the bone anchor (90) at a stable angle in the fork head (10).

Description

[0001] Temporarily fixable osteosynthesis device for vertebrae with rotatable

[0002] Fixing element

[0003] State of the art

[0004] Various osteosynthesis devices for treating the spine, such as pedicle screws, are known in the prior art. Such osteosynthesis devices are used to correct spinal misalignments or stabilize fractures. The osteosynthesis devices are inserted and secured into the vertebrae and then connected to one another via longitudinal rods, or so-called connecting rods, in order to fix the vertebrae in a desired position. The longitudinal rods are mounted and secured to the osteosynthesis devices in a non-slip manner using locking elements, such as grub screws or other closure elements. Pedicle screws are preferably used as osteosynthesis devices. These have a bone anchor that is pivotally mounted in at least one plane using a fork head and is angularly stable when the grub screw is fixed.Bone screws with a ball head are preferred as bone anchors. Osteosynthesis devices with a bone anchor and fork head are typically mounted so that the bone anchor is guided from the proximal end into the fork head through the distal opening of the fork head. This only works if the outer diameter of the bone anchor shaft is smaller than the ball head diameter of the bone anchor and the outer diameter of the bone anchor shaft is smaller than the diameter of the distal opening of the fork head. Mounting is problematic if the outer diameter of the bone anchor shaft is larger than the opening diameter of the fork head and / or the ball head diameter of the bone anchor.

[0005] A pedicle screw (DE102011053295A1) is known from the state of the art, which can be temporarily locked, thus allowing a broader range of applications in the treatment of spinal instabilities. This allows polyaxially movable pedicle screws to be inserted into the vertebrae in any orientation, and the user can then temporarily clamp the angle between the fork head and the bone anchor. With temporarily locked polyaxiality, corrective forces can be introduced to the bone anchor via the fork head, directly affecting the alignment and position of the vertebrae. Without this temporary clamping, such corrective maneuvers are impossible or difficult to perform.Such an arrangement requires that the compression piece be permanently clamped using an instrument, and that the instrument be attached to the screw at all times to maintain the compression force necessary for temporary clamping. In some spinal correction maneuvers, such as the correction of deformities and scoliosis, there is no space for such instruments. Therefore, it would be desirable to provide a screw implant capable of independently maintaining the temporary clamping once the

[0006] Instruments are removed. From the application DE102018102173B3, a pedicle screw anchor is known in which the temporary compression force is permanently maintained by providing a detachable pin element. However, this design requires a lever-like actuation of the pressure piece to generate the temporary clamping. This results in increased combined compression and bending stress on the pressure piece, which leads to a mechanical limitation of the maximum temporary clamping effect. Furthermore, it is necessary that the material thickness of the pressure piece is dimensioned such that these loads do not have a destructive effect. As a result, such a pedicle screw is greater in height than a regular pedicle screw. It is therefore desirable that the temporary clamping effect is not initiated via the pressure piece itself, but acts directly on the bone anchor head area.This means that the pressure piece is mechanically decoupled during temporary clamping and the osteosynthesis device can provide reserves with regard to the maximum clamping effect.

[0007] Furthermore, it is clear that none of these temporarily clampable pedicle screw concepts is capable of accommodating screw shafts coming in from the distal end. They can only be used with bone anchors where the outer diameter of the bone anchor shaft is smaller than the diameter of the distal opening of the fork head.

[0008] The object of the invention is therefore to provide a temporarily clampable osteosynthesis device, in particular a pedicle screw, which allows a bone anchor to be mounted from distally and that the pressure piece is not loaded when the temporary clamp is actuated, but is only subjected to a compressive force when the osteosynthesis device is finally locked with the connecting rod and the closure element.

[0009] This results in a modular screw system, which has advantages in terms of reduced capital commitment for the user and allows for a larger overall screw portfolio. On the other hand, the distribution of force and flow during temporary clamping without the mechanical involvement of the pressure piece results in a significant increase in stability compared to previous concepts, and the pedicle screw can be made smaller. At the same time, the inventive concept is intended to independently maintain the temporarily created clamping, even when all instruments have been removed.

[0010] Description of the invention

[0011] The invention relates to an osteosynthesis device, in particular a polyaxial pedicle screw, comprising a bone anchor having a head, a fork head that is U-shaped in side view, a pressure piece located therein, and an internal fixation element guided in a transverse opening. The fixation element is suitable for temporarily clamping the bone anchor head region in all degrees of freedom by rotation about the transverse opening axis, without the need for a pressure piece or, if present, without being loaded. In the preferred embodiment, it is possible to initiate the clamping effect indirectly via an adjusting element or directly via the fixation element itself, without the connecting rod or grub screw being present. Since this is not a final clamping with an inserted connecting rod, this type of clamping is called temporary clamping.With temporary clamping, the user can convert a polyaxial screw into a monoaxial screw at a desired angular position during surgery. This means that all rotational degrees of freedom of a polyaxial screw are temporarily locked. The screw behaves monoaxially. This allows the user to manipulate the vertebra to be treated both translationally and rotationally until a connecting rod is inserted in the desired final position and fixed with the grub screw. Such corrective maneuvers are not possible with a polyaxial screw, as a corrective maneuver initiated externally by the patient results in free movement of the polyaxial ball joint and is therefore not transmitted to the vertebra. This only works when the rotational degrees of freedom in the ball joint are deactivated, i.e., temporarily clamped.

[0012] Regardless of the temporary clamping, after implantation of the osteosynthesis device into the bone, a connecting rod must be inserted and the osteosynthesis device must be finally fixed in all degrees of freedom using a locking element. This is done by screwing the locking element tight. When the locking element is firmly tightened, an axial compression force is transferred from the locking element to the connecting rod, which presses on the rod support points of the pressure piece and creates a minimal relative movement of the pressure piece further distally, so that the bone anchor is clamped in the ball seat with a stable angle. Ideally, two or more osteosynthesis devices are connected to one another using a connecting rod.

[0013] The fork head is designed so that a connecting rod can be inserted and secured to the fork head with a locking element. As already mentioned, this creates a stable angle clamp between the bone anchor head area and the fork head. The stable angle clamping with the aid of the locking element and the stable angle clamping with the aid of the fixation element function independently of each other in the inventive structure. They can be activated separately or in combination.

[0014] In a preferred embodiment of the osteosynthesis device, the fork head has a through-hole and forms two fork legs in the proximal direction with an internal thread for a locking element. In the distal direction,

[0015] A ball head receiving area is provided in the through opening, in which a

[0016] Bone anchor is pivotally mounted. Bone screws, which can be screwed into a bone, are preferably used as bone anchors. However, hooks, blade-like anchors, clamps, nails, and other types of bone anchors can also be used. The key features of a bone anchor are a spherical head, a neck region, and a region that can be anchored or fixed in or to the bone. This patent application will primarily focus on the fork head, and the term "bone anchor" refers to any conceivable element that can be connected to a bone.

[0017] An essential feature of a preferred embodiment is that the center of the internal thread and the center of the ball head receiving area define the position and orientation of the central axis. An axial opening for an adjusting element is provided laterally and at a distance greater than the diameter of the locking element. The axial opening is arranged mainly parallel to the central axis. This allows the adjusting element to be driven from the same direction as the locking element using instruments. The adjusting element is guided in the axial opening so that its length can be adjusted. The term axial opening refers not only to openings that are completely enclosed by material, but also to partial openings or partial cutouts such as C-shaped cutouts perpendicular to the central axis.

[0018] An additional opening, a transverse opening, is provided perpendicular to the axial opening and the central axis. The transverse opening creates a connection between the axial opening and the through-opening of the fork head. The fixation element is guided in this transverse opening, allowing it to rotate around the transverse opening axis. By introducing a torsional moment around the transverse opening axis, the fixation element clamps the head of the bone anchor in the fork head at a stable angle. The transverse opening, or the axis of the transverse opening, is arranged approximately orthogonal to the central axis and also orthogonal to the axial opening.

[0019] The temporary clamping or compression force is preferably generated by adjusting an adjusting element that is guided in the axial opening. The compression force of the adjusting element is transferred or redirected to the fixation element, causing the fixation element to rotate around the transverse opening axis, thereby generating a torsional moment, which leads to the temporary clamping of the bone anchor head area in the fork head.

[0020] The temporary clamping effect can be significantly increased if a lever is provided on the fixation element. Actuating the lever forces a rotation of the fixation element and thus triggers the temporary clamping. For the assembly, it is necessary that the fixation element protrudes laterally beyond the walls of the fork head so that the lever is firmly connected to the fixation element. In an alternative embodiment, the adjusting element can now act on the end of the lever in order to permanently apply a force to the lever without additional instruments. Alternatively, it is also conceivable that the temporary clamping or the introduction of a compression force can take place via the fixation element itself. For this to happen, for example, the fixation element and the transverse opening must engage with each other by means of a threaded section, thus enabling length adjustment.This length adjustment shifts the fixation element along the transverse opening axis. If a diameter change is planned along the fixation element, a force-fit connection can be achieved between the fixation element and the head area of ​​the bone anchor.

[0021] Ideally, the fork head provides at least one lateral recess or material thickening to accommodate the axial opening, transverse opening, and the elements required for actuation (adjusting and fixing elements). In the alternative embodiment with an additional lever, it is advantageous if a recess is provided on each of the two fork head legs (11, 12).

[0022] In a preferred embodiment, the fork head has a pressure piece which has a distally directed contact area with the bone anchor head area and a proximally directed rod bearing. In the area of ​​the bone anchor head area, a lateral opening or a partial cutout is provided, in which the fixation element is arranged so as to be freely movable. This enables activation of the fixation element without loading the pressure piece. In a preferred embodiment, the fork head can be mounted with bone anchors from the distal end. Due to this advantageous arrangement of the components, the bone anchors can be mounted relatively easily with the fork head by placing or pressing them on. The bone anchor can also be removed again using an aid, such as a release instrument.This allows the user to configure the osteosynthesis device according to the invention in a modular manner and assemble it in the operating room at a later time than during production. This makes it possible, for example, to first anchor or screw the bone anchor individually into the bone, and then attach the fork head to the already implanted bone anchor. This has the significant advantage that, after implanting the bone anchor, the surgeon has significantly more space and a better view of the surgical field compared to the otherwise fully implanted pedicle screws.

[0023] The advantage is that, on the one hand, larger bone anchors, i.e. bone anchors with a larger outer diameter than the distal inner diameter of the fork head, can be mounted. On the other hand, the bone anchor portfolio can be minimized because the user can combine the fork head and bone anchor during the operation instead of having to resort to a prefabricated, oversized portfolio. Such a portfolio must be kept in stock by the user and thus considerably more capital is tied up than would be required for the modular version according to the invention. For a modular design of the osteosynthesis device, it is advantageous if the pressure piece has open slots in the distal direction and thus at least three spring-elastic arms are formed on the head receiving area. The spring-elastic arms can deflect radially outwards and thus enclose the bone anchor head area.This allows a bone anchor to be clipped into the pressure piece from the distal direction. The pressure piece forms a cone at least in part at the distal end of the outer surface. At least one inner conical section is defined in the fork head at the level of the ball receiving area. This congruent section with the cone of the pressure piece and, when the locking element is activated, leads to the angle-stable clamping of the bone anchor head area with the fork head. Here, too, it is essential that the pressure piece provides a through-hole for the fixation element so that the pressure piece is not subjected to stress when the temporary clamping is activated.

[0024] A circumferential groove with a hook-like profile is provided on the proximal fork head area, providing a rear grip for an instrument. Other groove profile designs or other retaining features, such as openings that provide a rear grip for an instrument, are conceivable.

[0025] At the proximal end of the fork head, there may be additional, detachable sections with a threaded area that allow for repositioning the connecting rod. It is also conceivable that a sleeve-like access formed by two longer legs is provided, as used for minimally invasive access. The detachable leg extensions can optionally be connected to each other at the proximal end. Detachable connections, for example, refer to predetermined breaking points suitable for removing the extensions after the connecting rod has been finally fixed.

[0026] All metallic alloys known and accepted as orthopedic implant materials are suitable. These include, for example, titanium, cobalt-chromium, and stainless steel alloys. If conventional manufacturing of the fork head and locking ring is not possible or only possible with the greatest technological effort, additive manufacturing is the method of choice. Additive manufacturing of metallic alloys, also known as 3D printing, uses laser or electron beam melting processes.

[0027] Further features, advantages and details of the invention emerge from the appended patent claims, the drawings and the following description of preferred embodiments of the osteosynthesis device according to the invention.

[0028] Show short description of the drawings

[0029] Fig. 1 is an oblique view of the inventive

[0030] Osteosynthesis device with pre-location of spatial relationships,

[0031] Fig. 2 the fully implanted osteosynthesis device in a

[0032] Oblique view, Fig. 3a an oblique view of the osteosynthesis device according to the invention, and

[0033] Fig. 3b is an exploded view of the osteosynthesis device according to the invention consisting of a fork head, a fixing element, adjusting element, bone anchor and pressure piece,

[0034] Fig. 4 is a side view of the assembled osteosynthesis device according to the invention with a corresponding sectional view,

[0035] Fig. 5a, b show two different positions S1, S2 of the adjusting element. Fig. 6 shows an exploded view of an alternative embodiment in which the fixation element has a lever. Fig. 7 presents a side view of the assembled osteosynthesis device according to the invention from Fig. 6 with a corresponding sectional view.

[0036] Fig. 8a and 8b illustrate the functioning of the lever.

[0037] Fig. 9a, b show an alternative embodiment in which the lever is actuated with an actuating element.

[0038] Fig. 10 shows a side view with corresponding sectional view of the embodiment of Figs. 9a and 9b.

[0039] Description of the preferred embodiments

[0040] Described is an osteosynthesis device (1) for treating the spine, wherein more than one osteosynthesis device (1) is used to connect one or more vertebrae to one another using connecting rods (50), thus stabilizing the spine. Spatial coordinate references are defined for the osteosynthesis device (1), in particular for the fork head (10), such as the proximal direction (101) and the distal direction (102), which extend along a central axis (103). Radial extension (104) extends outward from the central axis (103), and circumferential extension (105) is defined by a constant radius and a variable circumferential angle (Fig. 1).

[0041] Fig. 1 shows an embodiment of the osteosynthesis device (1) according to the invention for treating the spine, comprising a fork head (10) which is U-shaped in a side view and has a through-opening (18) and the fork head (10) has two fork legs (11, 12) with an internal thread (16) in the proximal direction (101), and a connecting rod (50) can be received therein, and in the fork head (10) in the distal direction (102) in the through-opening (18) a

[0042] A ball head receiving area (19) is provided, in which a bone anchor (90) is pivotally mounted. A transverse opening (13) is provided in the fork head (10), which communicates with the through-opening of the fork head (18). A fixation element (30) is guided in this transverse opening (13) so as to be rotatable about an axis (130).

[0043] By introducing a torsional moment around the transverse opening axis (130), the fixation element (30) clamps the head region (91) of the bone anchor (90) in a stable angle in the fork head (10).

[0044] Due to the torsional moment on the fixing element (30), the head region of the bone anchor (91) in the fork head (10) becomes movable again. Fig. 1, 3a and 3b also illustrate that the fork head (10) of the osteosynthesis device (1) has a pressure piece (20) and that the pressure piece has a through-opening (28), a distally directed contact area with the bone anchor head region (29), a proximally directed rod bearing (25), which is delimited by two legs (21, 22) and has a lateral opening or partial cutout (23) in the region of the bone anchor head region (29), in which the fixing element (30) is arranged so as to be freely movable. If a connecting rod (50) is inserted into the U-shaped fork opening (15), the connecting rod (50) is in direct contact with the rod bearing of the pressure piece (25).If the locking element (60) is now fixed to the fork head (10), a compression force is transferred from the locking element (60) to the connecting rod (50), and from the latter to the pressure piece (20, 25), and from the pressure piece (20) to the bone anchor head region (29, 91), and the bone anchor (90) is forced against the distal ball seat region (19). This applied compression force then leads to the clamping of the polyaxiality.

[0045] The bone anchor (90) preferably has a head region (91) with a tool attachment point (92) located therein and has a bone thread (93) in the distal direction (102).

[0046] Fig. 3b shows a preferred design of the fixing element (30). Here, it is shown that the fixing element (30) is preferably designed in its primary overall form as a round rod or pin and is rotatably mounted in a concentric transverse opening (13).

[0047] Alternative designs of the fixation element (20) are also conceivable, but not shown here. For example, in a sectional view transverse to the transverse opening axis (130), at least one section of the fixation element is designed as a triangle, square, or polygon, or even as a triangle or polygon with transition curves, or as a solid round with lateral flattened areas, which serve to ensure that rotation of the fixation element (30) causes clamping at the bone anchor head region (91). It is also conceivable for the fixation element (30) to change its geometry along the transverse opening axis (130) in order to provide engagement features for anti-loss elements.

[0048] In the embodiment shown in Fig. 3b, the fork head (10) has an axial opening (14) in which an adjusting element (40) is guided. By adjusting the adjusting element (40), a compression force is generated which is transferred directly to the fixing element (30). This generates a torsional moment on the fixing element (30) about the transverse opening axis (130), which leads to the temporary clamping of the bone anchor head region (91) in the fork head (10). It is advantageous if the axial opening (14) for the adjusting element (40) is arranged parallel to, but at a distance from, the central axis (103). The osteosynthesis device (1) preferably has a pin-shaped adjusting element (40) which has a tool attachment point (42) on the head (41) in the proximal direction (101) (Fig. 3a, b). The adjusting element (40) is designed to be detachable and can also be removed if necessary.

[0049] With the adjusting element (40) removed and the fixing element (30) not temporarily clamped, this osteosynthesis device (1) behaves like a polyaxial pedicle screw.

[0050] Fig. 3b also shows that, when an axial opening (14) is provided in a fork head leg (11, 12), it is advantageous for the fork head (10) to have a lateral material bead that merges into one of the legs (11 or 12) so that the transverse opening (13) as well as the axial opening (14) can be produced. Fig. 3b also shows that the fork head (10)

[0051] Projections, openings, grooves, webs, profiles or other features (17) which are suitable for gripping, engaging or engaging behind with an instrument. If the adjusting element (40) is part of an instrument, this instrument connection feature (17) can be used to introduce a tensile force on the fork head (10), which acts as

[0052] Antagonist for the introduction of a compression force via the actuating element (40).

[0053] Fig. 4 shows the osteosynthesis device (1) according to the invention in a side view and in section. It can be seen that the center of the internal thread (16) and the center of the

[0054] Ball head receiving area (190) define a central axis (103), and this central axis (103) does not intersect with the transverse opening axis (130). The transverse opening axis (130) is arranged approximately orthogonally and at a distance from the central axis (103). The fixing

[0055] Element (30) protrudes at least partially into the passage opening

[0056] (18) of the fork head (10) and rests against the ball head area (91, 31) of the bone anchor (90). The transverse opening (13) communicates with the through-opening of the fork head (18) via a wall cutout (185). Through this wall cutout (185), the fixation element (30) has direct access to the bone anchor head area (91). Ideally, the contact area of ​​the fixation element (31) is located precisely at this point in the wall cutout (185).

[0057] Furthermore, it is advantageous if the contact point (31) for initiating the temporary clamping in the proximal direction (101) is located above the equator (94) of the bone anchor head region (91) or the center (190) of the ball head receiving region in the fork head (19). This ensures that, when a compression force is introduced by the fixation element (30), the bone anchor head region (91) is not only pressed in the opposite direction or against the opposite inner wall of the fork head (18), but is also partially forced into the ball seat (19). Thus, the bone anchor (90) in the fork head (10) is centered in the ball seat (19) under the action of force. As a result, the compression force is directed towards the centre point (190) of the ball-like bone anchor head region (91), so that even when the bone anchor (90) is pivoted, there is a similarly large contact area between the fixing element and the bone anchor head region (31, 91).

[0058] The radially inwardly directed contact area (31) of the fixing element (30), which is responsible for the temporary clamping, lies directly on the head area (91) of the bone anchor (90).

[0059] It is advantageous if this contact area (31) is at least partially concave in a side view or approximates at least a section of the outer surface of the bone anchor head area (91). For an optimized clamping effect, it is advantageous if the radially inwardly directed contact area (31) of the fixing element (30) has an increased roughness, notches or

[0060] teeth (Fig. 4). It is advantageous for production if the radially inward-facing contact area is designed as a cutout of the otherwise pin-like fixing element. In order for the pin-like fixing element (30) to be able to exert a clamping effect, it is advantageous if the head area of ​​the bone anchor (91) is defined by a radius RI and the fixing element (30) at its thickest point by a radius R2, and the shortest distance between the central axis (103) and the transverse opening axis (130) is smaller than the sum of the radii RI and R2. This results in a calculated material overlap of the bone anchor head area with the fixing element. The contact area (31) cut out in the fixing element provides the corresponding free space to the bone anchor head area.Rotation of the fixation element (30) about the transverse opening axis (130) forces a material overlap, which then results in the clamping of the bone anchor head region (91) in the ball seat of the fork head (19). Alternatively, this can also be achieved via a sectioned eccentric as part of the fixation element (30). Fig. 4 also shows that an adjusting element (40) is provided.

[0061] By adjusting the adjusting element (40), a compression force can be generated which is transferred to or redirected by the fixing element (30), thereby generating a torsional moment about the transverse opening axis (130), which leads to the temporary clamping of the bone anchor head region (91) in the fork head (10). The adjusting element (40) is guided in the axial opening (14) in a length-adjustable manner. If the adjusting element (40) is part of the implant, it is advantageous if the axial opening (14) for the adjusting element (40) has an internal thread at least in some sections. In engagement with this, it is necessary for the adjusting element (40) itself to also have a thread (43) at least in some sections. This makes it possible for the introduced compression force to be maintained when the adjusting element (40) is screwed in or tightened.If the adjusting element (40) is part of an instrument, the adjusting element (40) itself does not need to have a thread, since the compression force to be introduced is generated by the instrument.

[0062] For the deflection of the compression force from the adjusting element (40) to the fixing element (30), it is advantageous if the fixing element (30) has at least one contact surface (382) which is in direct

[0063] Contact is made with a distal contact region (44) of the actuating element (40), and this contact (382, 44) is designed such that a compression force along the actuating element axis (140) is redirected into a rotation about the transverse opening axis (130). The contact surface (382) of the fixing element (30) acts as an integrated lever (Fig. 4). It is therefore important that the axis of the actuating element (140) is at a distance from the transverse opening axis (130). Furthermore, in this embodiment, the distal contact region (44) of the actuating element (40) is designed to be convex, at least in sections, in order to ensure tangential guidance or constant contact when rotation of the fixing element is initiated.

[0064] In Fig. 4, the essential characteristic feature can also be seen, namely that when the bone anchor head area (91) is temporarily clamped solely by the fixing element (30), the pressure piece (20) is always unloaded. Only by inserting and

[0065] By securing a connecting rod (50, 60), a force is applied to the pressure piece. This allows the fork head and the pressure piece to absorb greater mechanical loads, and the pressure piece can be designed with significantly less material than comparable concepts, which in turn has a positive effect on the overall height of the osteosynthesis device (1). For osteosynthesis devices (1) for the spine, the smallest possible overall height is important to optimally adapt to the patient's anatomical characteristics.

[0066] The osteosynthesis device (1) is designed in such a way that a connecting rod (50) can be inserted and fixed to the fork head (10) with a locking element (60), thereby achieving an angle-stable clamping between the bone anchor head region (91) and the fork head (10), and the angle-stable clamping is achieved with the aid of the

[0067] The locking element (60) and the angle-stable clamping can be activated independently of one another with the aid of the fixing element (30) and can also be combined with one another.

[0068] Fig. 5a and 5b show that the fixation element (30) can assume a position S1 around the transverse opening axis (130), in which a compression force is transmitted to the bone anchor (90), so that the bone anchor (90) is held at a stable angle in the ball seat (19), and the fixation element (30) can assume a second position S2, in which the bone anchor (90) is held movably in the ball seat (19). These positions of the fixation element (30) can be adjusted by adjusting the adjusting element (40). This can be seen from the different rotational positions of the fixation element (30, 31) in the wall cutout (185). Fig. 6 and Fig. 7 show an alternative embodiment of the

[0069] Osteosynthesis device can be seen, in which the clamping force can be increased by an additional lever (39). It is advantageous if the fixing element (30) extends beyond at least one lateral wall of the fork head (10) (32, 33) and the lever (39) is fastened thereto. Actuation of the lever (39) causes a rotation of the fixing element (30) and thus forces the temporary clamping of the bone anchor head region (91) in the fork head (10). The deflection of the lever is preferably initiated at a region (395) which has the greatest possible distance from the transverse opening (13) in order to achieve the lever effect, ie the

[0070] force amplification. Ideally, the fixing

[0071] Element (30) has two ends (32, 33) that project beyond the lateral wall of the fork head. The lever preferably has two legs (392, 394) that are connected to the lever at the ends of the fixing element (32, 33) or joined together (391, 393). It is advantageous if the joints additionally contain a positive connection (393) so that a higher transmission of loads is possible. Optimally, the lever is arranged outside the fork head (10) so that it can be actuated with suitable actuating means such as the actuating element (40, Fig. 9a, 9b) or an instrument not shown here. The actuation or switching between two actuating positions with the resulting clamping effect is described in the

[0072] Figures 9a and 9b show this.

[0073] Figs. 9a and 9b show a further preferred embodiment of the osteosynthesis device (1) according to the invention. Here, the pressure piece (20) has slots (26) open in the distal direction (102). As a result, at least three spring-elastic arms (27) are formed on the head receiving area (29), wherein the spring-elastic arms (27) describe a cone (271) on their outer side, at least in sections, and the bone anchor (90) can be inserted into the fork head (10) from the distal direction (102). This allows bone anchors (90) with a larger outer diameter to be mounted to the fork head (10).

[0074] In order to ensure that the pressure piece can be optimally clamped within the fork head (10), at least one inner conical section (183) is defined in the ball receiving area (19), which is congruent with the cone (271) of the pressure piece (20) and, upon actuation of the locking element (60), leads to the angle-stable clamping of the bone anchor head area (91) with the fork head (10) (Fig.

[0075] 9a, b and Fig. 10). Here too, it is necessary that the pressure piece has a lateral opening or at least a partial

[0076] The fixing element (30) has a cutout (23) through which it is guided and can move. This ensures that the pressure piece (20) is not subjected to stress when the temporary clamping is activated.

[0077] Also illustrated in Figs. 9a and 9b is an alternative embodiment in which the lever (39) can be actuated by an adjusting element (40). This design is suitable for maintaining the clamping effect by the adjusting means (40) without the need for instruments.

[0078] In Fig. 10 it can be seen that the fork head legs (11, 12) each provide a support surface (181) with an undercut that is effective in the proximal direction (101), and the pressure piece (20) has projections (24) directed radially outwards at the proximal end, wherein the projections (24) are designed to be resilient in the radial inward direction, so that the pressure piece (20) can be inserted into the fork head (10) from the proximal direction (101). The projections of the pressure piece (24) engage with the support surfaces (181) and the pressure piece (20) is secured in the proximal direction (101) but not subjected to force. In Fig. 10 it can also be seen that the fork head (10) has a

[0079] A region which, at least in sections, has a larger inner diameter (182) than the core diameter of the thread (16). This makes it possible, when the pressure piece is not yet fully locked into the final position with the fork head (10), to provide the spring-elastic conical region (27) of the pressure piece in the fork head (10) at the level of the inner diameter extension (182) with appropriate space for expansion for assembly with the bone anchor head region (91).

[0080] In Fig. 2 it is shown when the adjusting element (40) is guided within an axial opening (14) and is part of the

[0081] Osteosynthesis device (1) and has a predetermined breaking point (45) such that only a part of the adjusting element (40) remains in the patient after the final locking with the connecting rod (50) and the locking element (60). The same picture arises if the adjusting element (40) is part of an instrument and after the final

[0082] Locking with the connecting rod (50) and the locking element (60) is removed from the patient.

[0083] Alternatively, the adjusting element (40) can also be provided completely as part of the osteosynthesis device (1). After the final

[0084] Locking with the connecting rod (50) and the locking element (60) it remains in the patient (not shown). It is advantageous if the adjusting element (40) does not extend beyond the proximal end

[0085] (101) of the fork head (10).

Claims

Patent claims 1. Osteosynthesis device (1) for treating the spine, comprising a fork head (10) in a side view, which has a through-opening (18) and the fork head (10) has two fork arms (11, 12) with an internal thread (16) in the proximal direction (101), and a connecting rod (50) can be received therein, and a ball head receiving area (19) is provided in the fork head (10) in the distal direction (102) in the through-opening (18) and a bone anchor (90) is pivotably mounted therein, characterized in that a transverse opening (13) is provided on the fork head (10),which communicates with the through-opening of the fork head (18) via a wall cutout (185) and in this transverse opening (13) a fixing element (30) is rotatably mounted about a transverse opening axis (130) and the fixing element (30) clamps the head region (91) of the bone anchor (90) in the fork head (10) in an angularly stable manner by introducing a torsional moment about the transverse opening axis (130).

2. Osteosynthesis device (1) according to claim 1, characterized in that, with relief of the torsional moment at the fixing element (30), the head region of the bone anchor (91) in the fork head (10) becomes movable.

3. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the center of the internal thread (16) and the center of the The ball head mounting area (190) defines a central axis (103), and this central axis (103) does not intersect with the transverse opening axis (130).

4. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the transverse opening axis (130) is arranged approximately orthogonally and at a distance from the central axis (103).

5. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fixing element (30) is inserted at least sectionally into the through-opening (18) of the protrudes into the fork head (10) (185) and lies against the ball head area (91, 31) of the bone anchor (90).

6. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fixing element (30) has a radially inwardly directed contact area (31) which is directly adjacent to the head area (91) of the bone anchor (90), and this contact area (31) is at least partially concave in a side view.

7. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the radially inwardly directed contact area (31) of the fixing element (30) is in a Side view at least one section of the outer surface of the Bone anchor head region (91) approximated.

8. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the radially inwardly directed contact area (31) of the fixing element (30) has increased roughness, notches, or teeth.

9. Osteosynthesis device (1) according to one of the preceding claims Claims, characterized in that the contact point (31) for initiating the temporary clamping in the proximal direction (101) is located above the equator (94) of the bone anchor head region (91).

10. Osteosynthesis device (1) according to one of the preceding Claims, characterized in that the contact point (31) for initiating the temporary clamping in the proximal direction (101) is located above the center (190) of the ball head receiving area in the fork head (19).

11. Osteosynthesis device (1) according to one of the preceding Claims, characterized in that the fixing element (30) is essentially pin-shaped.

12. Osteosynthesis device (1) according to one of the preceding Claims, characterized in that the fixing element (30) describes a radius R2 at at least one point, and the radius R2 is greater than the radial distance between the contact area (31) and the transverse opening axis (130).

13. Osteosynthesis device (1) according to one of the preceding Claims, characterized in that the head area of ​​the The bone anchor (91) is defined by a radius RI and the fixation element (30) at its thickest point by a radius R2, and the shortest distance between the central axis (103) and the transverse opening axis (130) is smaller than the sum of the radii RI and R2.

14. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fixing element (30) extends beyond at least one lateral wall of the fork head (10) (32, 33) and a lever (39) is attached to it (391, 393) and actuation of the lever causes a rotation of the fixing element (30).

15. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fork head (10) has an axial opening (14), and an adjusting element (40) is guided in the axial opening (14) and by adjusting the adjusting element (40) a compression force is generated which is transmitted directly to the fixing element (30) or indirectly via a lever (39), and thereby a torsional moment on the fixing element (30) about the transverse opening axis (130) is generated, which leads to the temporary clamping of the bone anchor head region (91) in the fork head (10).

16. Osteosynthesis device (1) according to one of the preceding claims, characterized in that a connecting rod (50) can be inserted and connected to a locking element (60) on the fork head. (10) can be fixed, thereby providing an angle-stable clamping action between bone anchor head area (91) and clevis head (10), and the angle-stable clamping with the help of the locking element (60) and the angle-stable clamping with the help of the fixing element (30) can be activated independently of each other and can also be combined with each other.

17. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) part of the osteosynthesis device (1) and remains in the patient after final locking with the connecting rod (50) and the locking element (60).

18. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) does not project beyond the proximal end of the fork head (10) in the proximal direction (101).

19. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) part of the osteosynthesis device (1), and has a predetermined breaking point and only part of the adjusting element (40) remains in the patient after final locking with the connecting rod (50) and the locking element (60).

20. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) part of an instrument and, after final locking with the connecting rod (50) and the locking element (60), from the Patients are removed.

21. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fixing element (30) can assume a rotational position S1 about the transverse opening axis (130), in which a compression force is transmitted to the bone anchor (90), so that the bone anchor (90) is angularly stable in the ball seat (19) is held and the fixing element (30) can assume a second rotation position S2, in which the bone anchor (90) is held movably in the ball seat (19).

22. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the axial opening (14) for the adjusting element (40) has an internal thread at least partially.

23. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) is pin-shaped and extends in the proximal direction (101) has a tool insertion point (42).

24. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the adjusting element (40) part of an instrument and the clevis head (10) projections, openings, grooves, ridges, profiles or other features (17) suitable for grasping, inserting or behind with an instrument, which serves to introduce a tensile force on the clevis head, which acts as an antagonist for introducing a compression force via the actuating element (40).

25. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fork head (10) has a pressure piece (20) and the pressure piece has a through opening (28), a distally directed contact area to the bone anchor head area (29), a proximally directed rod bearing (25) and in the area of ​​the bone anchor head area (29) a lateral opening or partial cutout (23) wherein the fixing element (30) is arranged to be freely movable.

26. Osteosynthesis device (1) according to one of the preceding claims, characterized in that the fork head (10) provides a pressure piece (20) and when the bone anchor head region (91) is clamped, the pressure piece (20) is unloaded solely by the fixing element (30).

27. Osteosynthesis device (1) according to one of the preceding claims 25 or 26, wherein c f e indicates that the pressure piece (20) has open slots (26) in the distal direction (102) and thereby has at least three spring-elastic arms (27) on the The head receiving area (29) is formed and the spring-elastic arms (27) describe a cone (271) at least partially on their outer side, and the bone anchor (90) can be inserted into the cable head (10) coming from the distal direction (102).

28. Osteosynthesis device (1) according to claim 27, characterized in that the fork head (10) in the ball receiving area (19) defines at least one inner cone section (183), which is congruent with the cone (271) of the pressure piece (20) and, when the locking element (60) is actuated, leads to the angle-stable clamping of the bone anchor head region (91) with the clevis head (10).

29. Osteosynthesis device (1) according to one of the preceding Claims 27 or 28, characterized in that the fork head (10) in the through-hole (18) has a region which, at least section by section, has a larger inner diameter (182) than the core diameter of the thread (16).

30. Osteosynthesis device (1) according to one of the preceding Claims, characterized in that the legs (11, 12) each provide a support surface (181) effective in the proximal direction (101) with an undercut, and the pressure piece (20) has radially outwardly directed projections (24) at the proximal end, wherein the projections (24) are designed to be spring-elastic radially inward, so that the pressure piece (20) can be inserted into the clevis head (10) from the proximal direction (101) and the projections of the pressure piece (24) can lock into the support surfaces (181) and the pressure piece (20) is secured but not subjected to force in the proximal direction (101).