US 20080275510 A1
A fixation device is used to fix an elongate element, in particular a wire, in an opening of a retaining structure, in particular of an implant plate. The fixation device has a main body. The main body is provided with a bore for receiving the elongate element. The main body is radially deformable in a clamp area, such that the diameter of the bore can be reduced. The main body has an outer contour which is designed in such a way that, when the fixation device is inserted into the opening of the retaining structure, the clamp area is deformed such that the elongate element is clamped securely in the bore.
1. Fixation device for fixing an elongate element in a seat of a retaining structure,
with a main body, which has an opening for receiving the elongate element,
wherein the main body, at least in a clamp area, is radially deformable relative to the elongate element, such that the dimension of the opening can be reduced,
the main body having an outer contour which is designed in such a way that, when the fixation device is inserted into the seat, the clamp area can be deformed such that the elongate element can be clamped securely in the opening.
2. Fixation device according to
3. Fixation device according to
4. Fixation device according to
5. Fixation device according
6. Fixation device according to
a screw with a screw shank having a screw thread, and
a pin with a shank without a screw thread.
7. Fixation device according to
8. Fixation device according to
9. Fixation device according to
10. Locking screw with a screw head, wherein the locking screw, at least in the area of the screw head, is provided with at least one opening.
11. Method of fixing an elongate element in a retaining structure with a locking screw,
wherein the locking screw contains a screw head and is provided, at least in the area of the screw head, with at least one opening,
the method comprising the step of fixing the elongate element inserted into the opening.
12. Combination of a fixation device according to
13. Combination according to
14. Combination according to
15. Combination according to
16. Combination according to
17. Arrangement with a combination according to
18. Arrangement according to
19. Arrangement according to
20. Arrangement according to
21. Arrangement according to
a retaining structure for receiving an endoscopy tube, the elongate element being designed as a tube or trocar,
a temporary intraoperative support element,
a surgical frame that can be fixed on the operating table,
an internal fixator,
a wire fixator,
a cable fixator,
an intramedullary pin,
an external fixator,
a scalpel holder, the elongate element being designed as a scalpel blade or as a scalpel shaft.
22. Osteosynthesis set, including at least two implant plates,
wherein each implant plate is provided with at least one seat for receiving a connecting arrangement,
with at least one connecting arrangement which can be inserted into a seat of each of the implant plates,
wherein the implant plates can be connected to one another and stabilized by means of the connecting arrangement of the implant plates.
23. Osteosynthesis set, including an implant plate with at least two sections,
wherein each section is provided with at least one seat for receiving a connecting arrangement,
with at least one connecting arrangement which can be inserted into a seat of each of the sections,
wherein the sections can be connected to one another and stabilized by means of the connecting arrangement of the implant plates.
24. Osteosynthesis set according to
the fixation device contains a main body, which has an opening for receiving the elongate element,
the main body, at least in a clamp area, is radially deformable relative to the elongate element, such that the dimension of the opening can be reduced,
the main body has an outer contour which is designed in such a way that, when the fixation device is inserted into the seat, the clamp area can be deformed such that the elongate element can be clamped securely in the opening.
25. Osteosynthesis set according to
has a screw head and
is provided with at least one opening, at least in the area of the screw head.
26. Osteosynthesis set according to
27. Osteosynthesis set according to
The invention relates to a fixation device, a combination of such a fixation device with an elongate element, and a corresponding arrangement with a retaining structure, and an osteosynthesis set, according to the features of the preambles of the independent patent claims.
Various types of fixation devices are used in bone surgery. In various indications, an elongate element, for example a Kirschner wire, has to be secured on a retaining structure, for example an internal or external fixator. Various arrangements are known for securing the wires in the retaining structure.
U.S. Pat. No. 4,941,481 and U.S. Pat. No. 4,620,533, for example, disclose clamp-like devices which can be guided in the manner of a clamping jaw over an elongate element and in so doing fix the latter. U.S. Pat. No. 6,702,814 discloses a clamping device which can be used for an external fixator and in which two clamping jaws form a channel for receiving an elongate element. One of the clamping jaws is elastically deformable in order to receive the elongate element.
U.S. Pat. No. 5,393,191 discloses an external fixator in which an elongate element can be guided into a slotted ball that can be pressed in between two clamping jaws. The orientation of the elongate element received in the ball can be adjusted in this way.
A surgical guide body is known from EP 1 202 675. The guide body is used to receive fixation elements and for this purpose has a plurality of openings inclined relative to one another. By means of an intermediate piece, a longitudinal fixation element, for example a wire, can be fixed by pressing, clamping or friction.
Other fixation devices for elongate elements are known from U.S. Pat. No. 2,346,346, U.S. Pat. No. 4,890,631, U.S. Pat. No. 5,702,394, EP 1 408 859, WO 03/105704, EP 1 736 109, EP 1 570 796, U.S. Pat. No. 4,621,627, EP 1 741 396, EP 1 306 057, U.S. Pat. No. 4,135,505, U.S. Pat. No. 4,127,119 or DE 3439795, WO 03/065911.
However, all these known solutions are associated with various disadvantages. In particular, many of the known solutions are made up of a plurality of individual elements. Production and use is therefore complicated and also expensive. A further disadvantage of known solutions is that the elongate elements to be fixed can often be secured only in one direction, or they can be secured in different directions only by means of structurally complex solutions.
It is true that EP 1 202 675 discloses a solution in which a position is possible in different directions without complicated ball joints. However, different directions are in this case also only possible in a defined and limited number according to preformed, inclined openings of the guide body. A correction of the direction is not possible.
It is therefore an object of the present invention to avoid the disadvantages of the known solutions, in particular therefore to make available a fixation device for fixing elongate elements which is easy and inexpensive to produce and can be handled in a simple manner. The fixation device is nonetheless intended to allow the direction of the elongate element to be selected as freely as possible and, if appropriate, to be corrected. A further object of the present invention is to make available a corresponding fixation device that can be repositioned in a simple manner, for example for fixing an elongate element at a different angle than originally provided.
A further object of the present invention is to make available such a fixation device in combination with an elongate element, and an arrangement with such a combination and with an additional retaining structure, which also meet the abovementioned objects.
A further aspect of the invention additionally concerns an osteosynthesis set made up of at least two implant plates. When treating osteoporotic bone in particular, a problem that often arises is that implant plates with threaded screws cannot be anchored sufficiently securely in the bone substance. According to this aspect of the invention, it is an object to make available an osteosynthesis set which is suitable for solving the known problems, in other words which permits a secure fixation of the implant plates even when insufficient or unsuitable bone substance means that conventional fixation with a screw is not possible or the hold of the screw does not provide adequate stability.
According to the invention, these objects are achieved with a fixation device, with a combination of such a fixation device and an elongate element, with an arrangement having such a combination, and with an osteosynthesis set, these having the features of the characterizing parts of the independent patent claims.
The fixation device according to the invention is used to fix an elongate element, in particular a wire, pin, tube or a thread, in a seat of a retaining structure. The retaining structure is typically a plate. However, the term retaining structure is to be interpreted widely. Applications are also conceivable in which the retaining structure primarily applies the clamping forces described below, and is not used for actually holding the fixation device. The fixation device has a main body. The main body is provided with an opening, in particular a continuous bore, for receiving the elongate element. The opening can extend in the longitudinal direction. It is also conceivable, however, to provide openings in the transverse direction (i.e. at an angle of more than 0° to the longitudinal axis) of the main body, for example for distraction. While the opening for receiving the elongate element is typically round (when used to receive cylindrical objects such as wires), other shapes of the opening are also conceivable. For example, a slit-shaped opening for receiving planar elongate elements is also conceivable. Differently shaped openings for receiving profiled elongate elements are also conceivable.
According to the invention, the main body, at least in an outer clamp area, is radially deformable such that the dimension of the opening, in particular the diameter of the bore, can be reduced. In the context of the present application, outer clamp area is to be understood as that area in which the main body is compressed by contact with the seat in the retaining structure. The main body additionally has an outer contour which is designed in such a way that, when the fixation device is inserted into the opening of the retaining structure, the clamp area can be deformed radially such that the elongate element can be clamped securely in the opening. Viewed in the direction of the elongate element, the secure clamping can be effected axially at the same height at which the clamp area is arranged. It is also conceivable, however, to provide for the elongate element to be clamped axially at a distance from the outer clamp area of the main body. Before insertion into the retaining structure, the elongate element can easily be inserted into the opening of the main body. When inserting the main body into the seat of the retaining structure, the main body is radially compressed by virtue of the specific configuration of its outer contour. In this way, the elongate element is securely clamped in the opening of the main body, such that it can no longer be displaced in the axial direction. The solution according to the invention is particularly simple, since, in addition to the elongate element and the retaining structure, only one additional component (the fixation device) is necessary for fixing the elongate element.
According to a first preferred embodiment of the invention, the fixation device is provided, in its clamp area, with at least one slit. The slit extends at least partially in the direction of the opening and ends at least partially in the opening. The slit can reach as far as the outer wall of the fixation device. The slit does not necessarily have to extend in a plane and instead can have one or more bends or curves. By virtue of this at least one slit, the main body can be radially compressed particularly easily. One slit may itself be sufficient. However, any desired greater number of slits can also be provided. The slit or slits are arranged in the radial direction for example. However, it is also conceivable to provide areas of weakening in the main body by means of tangential or curve-shaped slits. The slit typically extends exactly in the direction of the opening for receiving the elongate element. However, it is also conceivable to provide the slit at angles relative to the axis of the fixation device. Alternatively, however, it is also conceivable for the main body to be made of an elastic material. In this case, a radial compression can be achieved even without a slit. In addition, in order to simplify the insertion of the elongate element, the main body can also be made up of several mutually movable parts. Two parts connected by a hinge are conceivable. These parts can be opened out for insertion of the element and then closed again and connected to each other. The axial fixation of the elongate element is then effected once again in the manner described above.
In addition, it is also conceivable for the main body to be made from several materials and with several components. For example, elastic material could be used for the clamp zone, and tough material for the locking zone and screwdriver zone. Such a fixation device can be produced, for example, by multi-component injection moulding.
According to another preferred embodiment, the fixation device, at least in the clamp area, is provided on its outer contour with at least one clamp surface. The clamp surface at least partially widens radially, seen in the circumferential direction. A main body with such a structure, but without an elongate opening and without slits, is known from WO 04/086990 for locking a bone screw in an implant plate. When the screw head with the clamp surfaces is brought by means of rotation into contact with corresponding wedge projections of a seat of a retaining structure, radial forces arise that lead to a compression of the main body. It has been found that such a locking screw is particularly suitable for fixation of elongate elements if it is provided with an elongate opening for receiving the element and with means for facilitating the radial compression, for example slits.
Moreover, the fixation device according to the invention particularly preferably has a main body which, seen in the longitudinal direction, has a rounded outer contour in the area of the clamp surface, in particular at least partially an approximately spherical, spiral, parabolic, elliptic or hyperbolic contour. A contour is generally preferred which allows the direction of the fixation device in a seat of a retaining structure to be adjusted in an almost unlimited manner within a defined angle range. No additional components such as ball joints, clamping jaws or the like are needed for this purpose. It is also conceivable, however, to provide a main body with a cylindrical or conical outer contour, if at the same time a retaining structure with a seat is made available which has a correspondingly rounded contour. The outer face of the main body and/or the seat of the retaining structure can additionally be structured, for example with fluting or knurling.
According to another preferred embodiment of the invention, the fixation device, at least in its clamp area, is designed as a screw head. The design as a screw head in particular permits simple rotation of the fixation device in the circumferential direction. In the above-described design with clamp surfaces widening radially in the circumferential direction, the radial compression can be achieved in a particularly simple manner by rotation using a screwdriver, for example with a cross-head, Torx, hexagon socket or variations thereof, for example the Applicant's “HexaDrive”.
On its main body, the fixation device can additionally be provided with a screw shank with a screw thread. It is also conceivable, however, to additionally provide the fixation device with a shank of a pin. Therefore, depending on the application, it may be advantageous to use a fixation device composed exclusively of a main body, or a fixation device in which the main body is additionally provided with the shank of a pin or of a screw.
According to another preferred embodiment of the invention, the fixation device, when designed as a screw head in its clamp area, can additionally be provided with an extension above the clamp area. The extension is designed as a seat for a screwdriver. In this way, a torque can be applied particularly easily to the fixation device.
According to another preferred illustrative embodiment of the invention, the at least one slit, seen in the longitudinal direction of the fixation device, extends at least over the clamp area. It is also conceivable, however, for the slit or slits to extend over a longer axial area, in order to further increase the deformability and flexibility of the main body. At most, the slits extend along the entire length of the fixation device. By suitable choice of length of the slits, it is possible to adjust the clamping action on the elongate element.
According to another preferred embodiment of the invention, the inner surface of the opening can be structured. In this way, it is possible, by means of an additional form fit, to achieve increased retention in the axial direction as a result of the radial compression. In other words, this means that, with a given clamping force, a greater force would have to be applied to the elongate element in the axial direction in order to tear it from the fixation device.
In accordance with the above embodiments, one aspect of the invention is also that a locking screw known per se is additionally provided with a longitudinal bore and, in the area of the screw head, with at least one slit. It is particularly preferable here to use a locking screw of the type shown and claimed in WO 2004/086990. The subject matter of said application, and in particular of the claims of WO 04/086990, is hereby expressly incorporated in the present application.
A further aspect of the invention therefore lies in the use of such a locking screw for fixation of an elongate element in a retaining structure. By using a multi-directional locking screw, however, the elongate element can also be fixed in the longitudinal direction in a defined angle position, which can be freely selected within a range of angles.
Yet another aspect of the invention concerns the combination of a fixation device as described above and an elongate element. The elongate element is selected from the group including wires, rods, pins, profiles, springs, hollow tubes, or an instrument for manipulation, for example a scalpel or spatula (e.g. for manipulations on the brain). If the elongate element is designed as a wire, rod or pin, applications are possible for example with an internal fixator or an external fixator. If the elongate element is designed as a profile or a hollow tube, applications as an endoscopy tube or for fixation of a drill guide are also conceivable, for example. If the elongate element is designed as a fixture for a scalpel, the fixation device according to the invention can additionally be used as scalpel holder for holding a scalpel. The shaft of the scalpel can be inserted into the elongate bore. In such an application, however, it is also conceivable not to provide a longitudinal bore in the fixation element, and instead to directly fit a part of the blade of the scalpel into slits present on the fixation element.
To increase the axial clamping effect, the elongate element can additionally have a structured surface.
It is also conceivable, depending on the application, to provide the elongate element with a thread or with knurling in the longitudinal direction or transverse direction or also to provide it with a drill helix.
According to another preferred embodiment, the elongate element can be provided with a tip which is designed as a lancet or trocar, or which is provided with a self-cutting or self-drilling thread.
A cable/cord is also conceivable as an elongate element for transmitting tensile forces or for connecting torn soft-tissue parts such as tendons or ligaments or for fixing bone fragments.
A further aspect of the invention concerns an arrangement composed of the above-described combination of a fixation device and an elongate element together with a retaining structure. The retaining structure has at least one seat for a fixation device.
The seat for the fixation device is particularly preferably provided with radially inwardly directed projections or tapers. These tapers, together with the clamp surfaces on the fixation device, lead to a radial compression of the main body. To permit the simplest possible multi-directional positioning of the fixation device and therefore also of the elongate element held therein, the opening is also preferably provided with an inner wall which, in the longitudinal direction, has at least partially an approximately spherical, spiral, parabolic, elliptic or hyperbolic shape. In particular, the opening is designed in accordance with the disclosure and claims in WO 04/086990.
The retaining structure can, for example, be designed as a retaining structure for an endoscopy tube, which is retained in the retaining structure by the fixation device. In this case, the elongate element is an endoscopy tube.
The retaining structure can also be designed as a temporary intraoperative support element, for example as a fixation ring for an arthrodesis set.
Typical temporary intraoperative applications are applications in which certain bones are intended to be fixed for a limited time. Before the end of the surgical intervention, the corresponding support structure is removed. Indications are, for example, arthrodesis or partial arthrodesis of the wrist, neurosurgery, osteotomies, correction of fractures, and minimally invasive interventions, for example transbuccal interventions or spinal column surgery. External fixator is understood as an application in which, following surgery, the stabilizing or fixing structures are used outside of the body for avoiding bone movements and therefore for healing fractures. It is also conceivable, however, to fix certain degrees of freedom of structures (e.g. two bones connected by a joint) and to leave other degrees of freedom of the same structure deliberately alone in terms of their mobility (dynamic external fixator). This permits early postoperative physiotherapeutic exercise for preventing adhesion of soft-tissue parts and stiffening of the affected joints. These can typically be osteotomies, corrections or fracture treatments. Application in a ring fixator is also conceivable, where several rings can be fixed to one another likewise by means of the fixation device according to the invention. A use in the treatment of fractures of the upper arm is also conceivable, where the ball of the joint is held with a threaded wire, and the position can be very finely adjusted via a nut that bears on the screw head (pull-push instrument).
The retaining structure can additionally be formed by a surgical frame which can be secured by the fixation device to an operating table, for example in neurosurgical applications for holding drill sleeves or guide sleeves or spatulas.
In an application as an internal fixator, the arrangement as an implant for avoiding bone movements and for healing fractures remains permanently in the body. Typical applications may be arthrodesis or partial arthrodesis, stiffening of the spine, treatment of long bones in proximity to the joints, the epiphysis, all osteotomies, corrections or fracture treatments, wire osteosynthesis, using a plate with at least one hole, or skeletal anchoring in orthodontics. A wire fixator or cable fixator for generating tensile forces in soft-tissue parts is also conceivable.
In an application as an endoscope, manipulations in the body can be performed via the bore in the fixation device (for example in neurosurgery, oral surgery, orthodontics or facial surgery, in particular in transbuccal interventions, or in surgery of the spinal column or of the pelvis).
In the three last-mentioned cases, the elongate element is typically a wire or a tube/sleeve. Finally, the retaining structure can also be designed as a holder for an instrument, such as a scalpel, and in this case the elongate element is the blade shaft of the scalpel or a part of the blade.
While surgical applications have primarily been described here, other applications of the fixation device according to the invention, of the combination with an elongate element, and of the arrangement according to the invention are also conceivable. For example, such constructions can be used as quick-coupling systems for K-wires/drills in driving or drilling machines, as clamping mechanisms for grip pieces, e.g. in electrosurgery or for bone distraction (e.g. of palate, alveolar ridge). In applications for distraction, the elongate element can, for example, be designed in two parts, one part having an inner thread and one part having an outer thread. A fixation device with two transversely bored main bodies is used to receive one of the parts respectively. If the main bodies are each anchored in a bone fragment, the parts can be secured and used for distraction.
Other applications are also conceivable, however, e.g. in the construction field, e.g. in shelving, scaffolding, pegging (optionally with axial compression) or for shoring.
A further aspect of the invention concerns an osteosynthesis set. The set is made up of at least two implant plates or of one implant plate with at least two sections. The implant plates or the sections each have at least one seat for receiving a connecting arrangement. The set additionally comprises such a connecting arrangement. The connecting arrangement can be inserted into a respective bore of the plates or of the sections. The implant plates can be connected to one another and stabilized by means of the connecting arrangement of the implant plates. The plates are prevented from moving relative to each other along the elongate element. The firm fixation results in a connection of one or more plates. Fragments are then repositioned and fixed on this structure. In the case of a plate with two sections, a connection of one section, for example a tab of a plate, to another plate section can be created. This can be advantageous, for example, when the connection between the two plate sections has to be designed, for clinical reasons, such that it can transmit only a slight load or indeed no load or, for clinical reasons, is removed after the connection is established.
By virtue of the connecting arrangement, two or more such implant plates can be secured/connected at several locations of a bone, even when the bone, on account of its size or structure (internal makeup), is not suitable for receiving a bone screw for fixation of the implant plates.
It is also conceivable, in this context, to provide implant plates with tab-like parts that are angled off. The connecting arrangement can then be secured in a seat in this tab. This is particularly advantageous when, for anatomical reasons, the connection described above is not possible with flat plates, for example because the planes in the area of the seat are not arranged relative to one another by an angle which is smaller than the pivoting angle of the fixation elements. The angled-off parts then form small units that offer a position that can be used for the connection.
The connecting arrangement particularly preferably comprises a fixation device of the type described above. In this way, clamping wires can be secured in a particularly easy way in the openings of the implant plates. For certain applications, for example cranial and maxillofacial applications, it is also conceivable to skew the angle of the seat relative to the plate, that is to say to orient the axis of the seat not perpendicular to the plane of the plate. A positioning of the screws in a wider angle range can thus be achieved, e.g. in a range of 15° (30°−15°) to 45° (30°+15°) for a seat inclined by 30°. In thin plates in particular, the plate can be thickened locally in the area of the seat. In this way, space is created for the inclined arrangement of the locking contour in the seat.
Alternatively, however, it is also conceivable that the connecting arrangement comprises an elongate element with a thread at at least one end. In addition, the connecting arrangement is in this case provided with a connecting element, e.g. a nut, into which the thread can be screwed and by means of which the elongate element can be secured in one or both of the plates.
The invention is explained in more detail below on the basis of illustrative embodiments and with reference to the drawings, in which:
The main body 11 is additionally provided with a bore 12 (see
To generate a rotation movement, the main body 11 is additionally provided, in the area of the bore 12, with a seat 5 for a corresponding tool, for example a screwdriver.
In medical applications, the fixation device according to the invention is made of a biocompatible material. Typically, titanium can be used. Other materials are also conceivable, such as stainless or bioabsorbable materials. It is also possible to use alloys with shape-memory properties, for example Nitinol or generally superelastic materials, and for example also plastic.
The dimension of the fixation device according to the invention depends on the particular field of application. Typically, for applications in the surgical field, fixation devices with a diameter of ca. 2 to 7 mm, bores with a diameter of ca. 0.75 to 1.4 mm and fixation devices with an overall height of ca. 1 to 5 mm are conceivable. The slits can typically have a slit width of 0.2 to 0.3 mm and extend over a height of 0.3 to 1.5 mm. Variations are of course conceivable, depending on the field of application, for example in spinal surgery where endoscopes with diameters of 10-50 mm and bores with diameters of 5-40 mm are known.
The plate 61 shown in
The osteosynthesis set shown in
Nut is understood here in particular as any type of abutment for the wire. The nut does not necessarily have to be arranged parallel to the plane of the plate. The nut can also have a certain pivoting range. The nut can also be able to be locked. Finally, the nut does not necessarily need to have an opening. A self-drilling wire tip can also drill itself a hole. In addition, the nut can also be preassembled in the plate.
To connect the plates according to
By means of this pivotability, the plates can be positioned exactly according to the anatomical conditions, without having to take into account the subsequent connection of the plates. In non-multidirectional and non-pivotable systems, compromises would have to be made when adapting them to the anatomical conditions.
However, for this purpose it is also possible to use a K-wire with a large end face with an element that folds open or a slotted wire.
The elongate elements are made of suitable materials depending on the particular application. Typically, titanium can be used for implantable elements. Other materials that can conceivably be used are stainless materials, shape-memory alloys, elements of superelastic materials, or also plastic.