Bone nail device

Abstract

A bone nail device (1) comprises: an outer tube (2) having a first bone connecting member (2b) and an internal thread (2a) extending over at least a portion of the inner surface of the outer tube (2); and an inner tube (3) having a second bone connecting member (3a). The inner tube (3) is arranged at least partially inside the outer tube (2) to allow sliding axial relative movement. There is a drive unit having: a drive motor (7) fixedly attached to the inner tube (3); and a displacement screw (4) having an external thread (4a) engaging the internal thread (2a) of the outer tube (2). A planetary gear (6) is provided in the drive unit, the planetary gear having an input end connected to the drive motor (7) and an output end connected to the displacement screw (4).

Description

Technical Field

[0001] The present invention relates to a bone nail device that can be fixed to at least two parts of an elongated bone and has two parts that can move relative to each other in an axial direction. The bone nail device can be used to move two bone parts relative to each other, for example, for use during fracture restoration or other treatments for bone lengthening, bone compression and / or bone transport. Background Art

[0002] International patent publication WO98 / 30163 discloses a distraction device for moving two bone segments apart, in particular for lengthening a gap in a bone or bridging a bone. The distraction device has an intramedullary nail that can be introduced into the bone marrow cavity, and comprises two parts that can be axially moved and can be fixed to one of the two bone segments respectively. The distraction device also has a drive unit that drives a drive shaft, and a device for converting the rotational movement of the drive shaft into a relative axial movement of the two parts of the intramedullary nail. The drive shaft drives a planetary roller held on a track, on which the planetary roller engages in a corresponding drive groove in a hollow body surrounding the planetary roller by means of a drive groove arranged on its outer periphery. Summary of the invention

[0003] The present invention seeks to provide a bone distraction device for improved bone lengthening, bone compression and / or bone transport based on a bone nail device comprising an inner tube disposed inside an outer tube.

[0004] According to the present invention, a bone nail device is provided, comprising: an outer tube having a first bone connecting member and an internal thread extending over at least a portion of the inner surface of the outer tube; an inner tube having a second bone connecting member, the inner tube being arranged at least partially inside the outer tube to allow sliding axial relative movement (e.g., by making the outer diameter of the inner tube smaller than the inner diameter of the outer tube); and a drive unit. The drive unit comprises: a drive motor fixedly attached to the inner tube; a displacement screw having an external thread engaging the internal thread of the outer tube; and a planetary gear having an input end connected to the drive motor and an output end connected to the displacement screw. Embodiments of the present invention have the following advantages: the drive portion (drive motor, displacement screw and planetary gear) can be integrated into the bone nail device and moved with the inner tube, thereby allowing the use of a minimum size to minimize complexity and easy placement in many bone surgery applications. In addition, depending on the exact application of the bone nail device, sufficiently high loads can be applied. The bone nail device can be operated after placement without obstructing or interfering with the tissue surrounding the bone. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The present invention will be described in more detail below with reference to the accompanying drawings, in which:

[0006] Figure 1A cross-sectional view of a bone nail device for bone lengthening, bone compression and / or bone transport according to an embodiment of the present invention is shown;

[0007] FIG. 2A to FIG. 2F showing cross-sectional views of bone nail devices for bone lengthening, bone compression and / or bone transport according to six exemplary embodiments of the present invention; and

[0008] FIG. 3A to FIG. 3F Cross-sectional views of bone nail devices for bone lengthening, bone compression and / or bone transport according to six other exemplary embodiments of the present invention are shown. DETAILED DESCRIPTION

[0009] Distraction osteogenesis (also called bone distraction) is a well-established surgical procedure for the treatment of the skeletal system, particularly in connection with fractures or bone reconstruction. In bone distraction, two segments of a bone are separated at a specific distraction rate, which varies between 0 mm and several mm per day. New bone is formed in the gap between the two segments and the bone is strengthened due to the natural healing process.

[0010] Bone distraction can be used for the purpose of bone lengthening. For example, a patient may have an asymmetrical pair of limbs, with one limb longer than the other, due to differences in limb growth during maturation. In this case, it is desirable to lengthen the shorter limb to match the longer limb. The shorter limb will be intentionally broken into two parts, and by using bone distraction, the two parts will be separated to lengthen the limb to the desired length.

[0011] Similarly, bone distraction can be used for bone removal purposes. For example, a patient may have a bone infection due to a previous fracture, resulting in the infected portion of the bone being removed. In this case, there may be a gap in the bone, and it is desired to form new bone in the gap. The bone will be intentionally broken, and through the use of bone distraction, bone can be moved to fill the gap where the bone is missing.

[0012] In other applications, it is necessary to hold two bone parts together under a certain compressive force in order to allow the fracture to heal under the correct circumstances.

[0013] In view of the perfect nature of bone distraction in the surgical field, various devices for bone lengthening, bone compression and / or bone transport purposes are known in the art. Intramedullary nails are common examples of such devices. Typically, intramedullary nails are cylindrical and implanted in the medullary cavity of a bone. These devices can generally be characterized by having two or more components coaxially arranged in a telescopic arrangement, wherein at least two components of the device are connected to the portion of the broken bone. By using a drive motor, two or more components of the intramedullary nail can be axially moved apart relative to each other, thereby forming bone lengthening, bone compression or bone transport.

[0014] Although intramedullary nails have been successfully used to perform bone distraction, these devices still have their disadvantages. For example, the need to adjust the length of the intramedullary nail after remote placement requires the use of a complex drive arrangement. Therefore, there is a need in the art to overcome these disadvantages and provide a bone nail device with a simple structure and a reliable operating drive arrangement.

[0015] For other bone lengthening applications, all parts of the intramedullary nail may have to move relative to each other, thereby extending the device and therefore increasing the overall length of the device. In view of the placement of fractures and / or connections to the bone, this may limit the desired length of bone lengthening. In addition, the extension of the intramedullary nail may also not have sufficient guidance, wherein if there is a small misalignment, this may result in bone lengthening, bone compression or bone transport of incorrect trajectory.

[0016] Embodiments of the present invention provide a bone nail device for improved bone distraction, thereby allowing bone lengthening, bone compression and / or bone transport. In other embodiments, reduced or at least reduced requirements for device size (primarily desired length) are achieved, and in even other embodiments, bone lengthening, bone compression and / or bone transport with guided trajectories, even arched or contoured trajectories, can be achieved.

[0017] Figure 1 A cross-sectional view of a bone nail device 1 suitable for bone lengthening, bone compression and / or bone transport according to an embodiment of the present invention is shown. The bone device 1 includes an outer tube 2 and an inner tube 3, which is arranged at least partially inside the outer tube 2 to allow sliding axial relative movement. Therefore, the inner tube 3 has an outer diameter that is smaller than the inner diameter of the outer tube 2, thereby allowing, for example, the inner tube 3 to move smoothly away from or toward the outer tube 2. The outer tube 2 has a first bone connecting member 2b, and the inner tube 3 has a second bone connecting member 3a. The first bone connecting member 2b and the second bone connecting member 3a are arranged to be connected to the separated bone parts with a firm attachment (for example, using a screw). In a specific embodiment, the first bone connecting member 2b and / or the second bone connecting member 3a include an orifice for accommodating a transverse bone fixation screw. The orifice may, for example, include a thread to easily allow the screw to be screwed through the orifice into at least a portion of the bone, thereby allowing the first connecting member 2b and / or the second connecting member 3a to be firmly fixed to the corresponding bone part. It should be noted that in Figure 1 In the embodiment shown, the first connecting member 2b and the second connecting member 3a include two apertures, but in general, Figure 1 Only exemplary embodiments are shown, and in other embodiments, the first connection member 2b and / or the second connection member 3a may include more or fewer apertures.

[0018] In the bone nail device 1, generally speaking, the outer tube 2 has an internal thread 2a extending over at least a portion of the inner surface of the outer tube 2, and the bone nail device 1 also includes a drive unit including a drive motor 7 fixedly attached to the inner tube 3, a displacement screw 4 having an external thread 4a engaging the internal thread 2a of the inner tube 3, and a planetary gear 6 having an input end connected to the drive motor 7 and an output end connected to the displacement screw 4. The configuration of the features as described above and their mechanical connection allow for sliding axial movement of the inner tube 3 relative to the outer tube 2. In addition, the use of the displacement screw 4 in this configuration avoids the need for an extension rod or spindle axis running along the entire length of the bone distraction nail device 1 when the bone distraction nail device 1 is equipped with a spindle drive mechanism for distraction.

[0019] exist Figure 1 In the exemplary embodiment shown, the combination of drive motor 7, transfer screw 4 and planetary gear 6 is positioned between first bone connecting member 2b and second bone connecting member 3a. This allows this combination to move together with inner tube 3, thereby providing a very compact and simple construction of bone nail device 1.

[0020] exist Figure 1 In the illustrated embodiment, a bearing 5 is attached to the transport screw 4 for bearing the axial load and allowing the transport screw 4 to rotate relative to the inner tube 3. The bearing 5 further reduces the friction between the transport screw 4 and the inner tube 3, thereby allowing the transport screw 4 to rotate more easily. The bearing 5 also allows for proper structural guidance of the axial load forces applied during operation of the bone nail device 1. A torque can be applied to the transport screw 4 to cause the transport screw 4 to rotate about its axis. The torque is applied by the output of the planetary gear 6 connected to the transport screw 4 via the drive motor 7 connected to the input of the planetary gear 6. The rotation of the transport screw 4 about its axial axis allows the outer thread 4a to engage with the inner thread 2a of the outer tube 2.

[0021] Since the transport screw 4 is connected to the drive motor 7 via the planetary gear 6 and the drive motor 7 is fixedly attached to the inner tube 3 , this allows a sliding axial movement of the inner tube 3 relative to the outer tube 2 as a result of the transport screw 4 rotating.

[0022] In this regard, the inner tube 3 can be moved away from the outer tube 2 (i.e., the inner tube 3 is withdrawn from the outer tube 2), thereby extending the overall length of the bone device 1, or the inner tube 3 can be moved toward the outer tube 2 (i.e., the inner tube 3 slides into the outer tube 2), thereby reducing the overall length of the bone nail device 1. These relative movements allow bone lengthening, bone compression and / or bone transport. The movement of the inner tube 3 to extend or reduce the overall length of the bone nail device 1 depends on the handedness of the internal thread 2a and the external thread 4a and the rotation direction of the transport screw 4.

[0023] For example, Figure 1As shown, the bone nail device 1 can be surgically implanted in the medullary cavity of the bone, wherein the first bone connecting member 2b is connected to the first part of the two-part broken bone, and the second bone connecting member 3a is connected to the second part of the two-part broken bone. The transfer screw 4 can be rotated so that the rotation direction allows the inner tube 3 to move away from the outer tube 2, thereby allowing the first part of the two-part broken bone to move away from the second part of the two-part broken bone, wherein the second part of the two-part broken bone remains in the same position. New bone is formed in the gap between the two parts of the broken bone, thereby performing bone lengthening.

[0024] exist Figure 1 In the illustrated embodiment, the planetary gear 6 controls the transfer of torque applied from the drive motor 7 to the translation screw 4. For example, the planetary gear 6 can be a reduction gear in which the rotational speed of the translation screw 4 is reduced (and the torque applied from the drive motor 7 to the translation screw 4 is increased), and thus, the planetary gear 6 can reduce the rate of bone lengthening, bone compression, and / or bone translation.

[0025] In addition, in other embodiments, the drive motor 7 is an electric motor that can be supplied with power via, for example, inductive transmission (such as wireless energy transfer). Other examples of how the drive motor 7 can be supplied with power can be via a direct wired connection to an internal power storage component (such as a battery) implanted in the patient's body itself, or via a direct wired connection to an external power source in an external environment outside the patient's body. Alternatively, the drive motor 7 can be a magnetic motor driven by an external magnetic drive actuator. For example, the drive motor 7 can include a permanent magnet motor, in which an externally applied alternating magnetic field can force the drive motor 7 into rotation.

[0026] More generally, embodiments of the present invention relate to a bone nail device 1 for bone lengthening, bone compression and / or bone transport, the bone nail device comprising: an outer tube 2 having an internal thread 2a extending over at least a portion of an inner surface of the outer tube 2 and a first bone connecting member 2b; an inner tube 3 having a second bone connecting member 3a, the inner tube 3 being arranged inside at least a portion of the outer tube 2 to allow sliding axial relative movement. The bone nail device 1 also includes a drive unit including a drive motor 7 fixedly attached to the inner tube 3, a transport screw 4 having an external thread 4a engaging the internal thread 2a of the outer tube 2, and a planetary gear 6 having an input end connected to the drive motor 7 and an output end connected to the transport screw 4. The first bone connecting member 2b and the second bone connecting member 3a can be connected to at least two portions of a broken bone, and by rotating the transport screw 4, the inner tube 3 moves relative to the outer tube 2, thereby allowing at least a portion of the broken bone to move relative to at least another portion of the broken bone, thereby performing bone lengthening, bone compression and / or bone transport. The drive unit may be completely housed within the outer tube 2, thereby achieving proper intramedullary positioning of the bone screw device 1 and functioning without hindrance once in place within the bone.

[0027] FIG. 2A to FIG. 2F Cross-sectional views of a bone nail device 1 for bone lengthening, bone compression and / or bone transport according to six exemplary embodiments of the present invention are shown. Figure 2A and Figure 2B Embodiments are particularly suitable for bone lengthening, Figure 2C and Figure 2D Embodiments are particularly suitable for bone transport, and Figure 2E and Figure 2F Embodiments are particularly suitable for bone compression.

[0028] In such FIG. 2A to FIG. 2F In the exemplary embodiment shown, the outer tube 2 includes a guide slot 2d, and the inner tube 3 includes a guide pin 3b extending through the guide slot 2d. The guide pin 3b may include a cylindrical body, and the guide slot 2d may include a long narrow aperture, the width of which is slightly larger than the diameter of the guide pin 3b, thereby allowing the guide pin 3b to slide fit in the guide slot 2d.

[0029] The combination of the guide slot 2d and the guide pin 3b extending through the guide slot 2d correctly aligns the sliding axial movement of the inner tube 3 relative to the outer tube 2 and, therefore, allows a correct trajectory of the bone nail device 1 without misalignment, wherein the trajectory of bone lengthening, bone compression and / or bone displacement is determined by the trajectory of the guide slot 2d. In addition, since the length of the bone nail device 1 does not change in the case of mutual movement of the inner tube 3 and the outer tube 2 applied by the drive unit 4, 6, 7, the surrounding bone parts or other nearby tissues are not disturbed during the use of the bone nail device 1.

[0030] exist FIG. 2A to FIG. 2F In the illustrated embodiments, the guide slot 2d comprises a linear aperture, thereby causing the bone lengthening, bone compression and / or bone transport to have a linear trajectory. In addition, in these embodiments, the outer tube 2 has a predetermined length, thereby allowing the entire bone nail device 1 to be positioned in a longitudinal borehole drilled into an elongated bone. FIG. 2A to FIG. 2B and FIG. 2E to FIG. 2F In the embodiment, the bone lengthening operation can be performed after the various bone parts are fixed to the first bone connecting member 2b and the second bone connecting member 3a, with the benefit that there are no moving parts outside the outer tube 2. This reduces the risk of trauma to, for example, surrounding tissue.

[0031] exist Figure 2C to Figure 2DIn the exemplary embodiment shown, the outer tube 2 includes a third bone connecting member 2c, which is positioned at the end of the outer tube 2 axially opposite the first bone connecting member 2b. Similar to the embodiments of the first bone connecting member 2b and the second bone connecting member 3a, the third bone connecting member 2c is arranged to be securely connected to at least a portion of the bone or a bone portion. In another embodiment, the third bone connecting member 2c includes an aperture for accommodating a transverse bone fixation screw, thereby allowing the outer tube 2 to be securely fixed to the bone portion. By Figure 2C to Figure 2D In the embodiment, the removal operation can be performed after the various bone parts are fixed to the first bone connecting member 2b and the second bone connecting members 3a, 2c.

[0032] Specifically, Figure 2C to Figure 2D The exemplary embodiment shown is particularly suitable for bone transport, wherein the first bone connecting member 2b and the third bone connecting member 2c are securely connected to the portion of the bone that remains in the same position, and the second bone connecting member 3a is securely connected to the portion of the bone that is transported.

[0033] For example, Figure 2C The bone nail device 1 shown is surgically implanted in the medullary cavity of bone.The first connecting member 2b, the second connecting member 3a and the third connecting member 2c are firmly screwed onto the first part, the second part and the third part of the bone that are respectively located at the top part, the middle part and the bottom part of the bone.For example, because of infection, in the second part of the bone, just below the position that firmly connects the second connecting member 3a, remove the small part of bone, thereby leave a gap in the bone between the position of the first connecting member 2b and the second connecting member 3a. In the third part of the bone, just near the position that firmly connects the third connecting member 2c, intentionally fracture the bone. Move the second (now middle) part of the bone to fill the gap that has lost bone towards the third part of the bone in the track determined by the guide groove 2d, thereby carry out bone transfer, and one after another, the second part of the bone is moved away from the first part of the bone, thereby form a new gap between the first part of the bone and the second part so as to form new bone.

[0034] exist Figure 2B and Figure 2E In the exemplary embodiment shown, the drive unit (i.e., the combination of the drive motor 7, the transport screw 4, and the planetary gear 6) is positioned away from the first bone connecting member 2b and the second bone connecting member 3a. In this regard, this configuration also allows for other bone transport and / or bone compression distraction procedures, wherein in a bone compression distraction procedure, for example, two parts of a two-part fractured bone are moved toward each other to fill a gap in the bone and subsequently compressed. Figure 2EIn the illustrated embodiment, bone compression and distraction can be performed by firmly screwing the first connecting member 2b and the second connecting member 3a to the first part and the second part of the two-part broken bone, respectively, and allowing the inner tube 3 to move within the outer tube 2 toward the position of the first bone connecting member 2b, thereby moving the two parts of the two-part broken bone toward each other, thereby performing bone compression and distraction.

[0035] FIG. 3A to FIG. 3F Cross-sectional views of bone nail devices 1 for bone lengthening, bone compression and / or bone transport according to six other exemplary embodiments of the present invention are shown. Figure 3A and Figure 3B Embodiments are particularly suitable for bone lengthening, Figure 3C and Figure 3D Embodiments are particularly suitable for bone transport, and Figure 3E and Figure 3F Embodiments are particularly suitable for bone compression.

[0036] exist FIG. 3A to FIG. 3F In the exemplary embodiment shown, the outer tube 2 includes a curved section 8 having a curved guide groove 8a. FIG. 2A to FIG. 2F The curved section 8 allows for bone lengthening, bone compression and / or bone transport having a non-linear trajectory as determined by the curved guide slot 8a, compared to the linear trajectory determined by the linear guide slot 2d described in the embodiment of FIG. This allows bone distraction procedures to be performed on bones that include a curved (e.g., bent, arched) trajectory (e.g., a clavicle or portion of a skull).

[0037] In an embodiment, the curved guide groove 8a has a curvature with a radius greater than 500 mm (e.g. greater than 1000 mm). It should be noted that the femur has a natural curved shape (e.g. with a curvature of 1700 mm) and this embodiment allows movement without the risk of (femoral) fracture when the bone nail device 1 is positioned in a fixed manner. In an exemplary embodiment, the curved guide groove 8a has a curvature that allows the inner tube 3 to move over the entire length of the curved segment 8. If the difference Δ (delta) between the inner diameter of the outer tube 2 and the outer diameter of the inner tube 3 divided by the length l of the curved segment 8 is large enough to accommodate the curvature of the curved guide groove 8a over the same length l, the inner tube 3 can extend over the entire range of the length of the curved segment 8. As Figure 3B , Figure 3D and Figure 3F As shown in the embodiment of FIG. 8 , the outer diameter of the inner tube 3 is smaller than the inner diameter of the outer tube 2 , thereby allowing the inner tube 3 to extend all the way into the curved section 8 and then hit the inner wall of the outer tube 2 .

[0038] In yet another embodiment, the inner tube 3 is flexible in its longitudinal direction, thereby allowing a better and less obstructed travel of the inner tube 3 inside the curved section 8 of the outer tube 2. For example, the inner tube 3 can be made of a flexible material to achieve this effect, such as carbon, plastic or fiber reinforced material. If the diameter of the inner tube 3 is small enough, flexibility can even be obtained when using (surgical) metals such as stainless steel or titanium.

[0039] exist FIG. 3A to FIG. 3F In the exemplary embodiment shown, the inner tube 3 further comprises a pivotable guide pin connection member 3c, which comprises a second bone connection member 3a and a guide pin 3b, which extends through the curved guide slot 8a. The pivotable guide pin connection member 3c allows the inner tube 3 to move axially in a smooth curved manner relative to the outer tube 2; in other words, the pivotable guide pin connection member 3c can substantially pivot and adjust the trajectory of the inner tube 3 relative to the outer tube 2 to follow the trajectory of the curved guide slot 8a, thereby preventing the movement of the inner tube 3 from being stuck due to an incorrect trajectory.

[0040] Otherwise, in addition to the bending features just discussed, the above FIG. 2A to FIG. 2F The embodiments discussed (including features such as the third bone connecting member 2c) are respectively FIG. 3A to FIG. 3F The features shown are the same, and the techniques for bone lengthening, bone compression and / or bone transport are also similar.

[0041] The invention has been described above with reference to a number of exemplary embodiments shown in the accompanying drawings. Modifications and alternative implementations of some components or elements are possible and are included in the scope of protection as defined in the appended claims.

Claims

1. A bone screw device (1), include: An outer tube (2) having a first bone connecting member (2b) and an internal thread (2a) extending over at least a portion of an inner surface of the outer tube (2); an inner tube (3) having a second bone connecting member (3a), the inner tube (3) being arranged at least partially inside the outer tube (2) to allow sliding axial relative movement, and A drive unit, the drive unit comprising: a drive motor (7) fixedly attached to the inner tube (3); a transfer screw (4) having an outer thread (4a) engaging the inner thread (2a) of the outer tube (2), and A planetary gear (6) has an input end connected to the drive motor (7) and an output end connected to the shifting screw (4).

2. The bone screw device according to claim 1, in, The first bone connecting member (2b) and / or the second bone connecting member (3a) comprises an aperture for receiving a transverse bone fixation screw.

3. The bone screw device according to claim 1, further comprising a bearing (5) attached to the translation screw (4) for bearing an axial load.

4. The bone screw device according to any one of claims 1 to 3, in, The combination of the drive motor (7), the transfer screw (4) and the planetary gear (6) is positioned between the first bone connecting member (2b) and the second bone connecting member (3a).

5. The bone screw device according to any one of claims 1 to 3, in, The outer tube (2) includes a guide groove (2d), and the inner tube (3) includes a guide pin (3b) extending through the guide groove (2d).

6. The bone screw device according to claim 5, in, The combination of the drive motor (7), the translation screw (4) and the planetary gear (6) is positioned away from both the first bone connecting member (2b) and the second bone connecting member (3a).

7. The bone screw device according to any one of claims 1 to 3, in, The outer tube (2) includes a third bone connecting member (2c) positioned at an end of the outer tube (2) axially opposite to the first bone connecting member (2b).

8. The bone screw device according to claim 7, in, The third bone connecting member (2c) includes an aperture for receiving a transverse bone fixation screw.

9. The bone screw device according to any one of claims 1 to 3, in, The outer tube (2) comprises a curved section (8) having a curved guide groove (8a).

10. The bone screw device according to claim 9, in, The inner tube (3) is flexible in its longitudinal direction.

11. The bone screw device according to claim 9, in, The inner tube (3) further comprises a pivotable guide pin connection member (3c), the pivotable guide pin connection member (3c) comprising the second bone connection member (3a) and a guide pin (3b), the guide pin (3b) extending through the curved guide slot (8a).

12. The bone screw device according to claim 9, in, The curved guide groove (8a) has a curvature radius greater than 500 mm.

13. The bone screw device according to claim 9, in, The curved guide groove (8a) has a curvature with a radius greater than 1000 mm.

14. The bone screw device according to any one of claims 1 to 3, in, The drive motor (7) is an electric motor.

15. The bone screw device according to any one of claims 1 to 3, in, The drive motor (7) is a magnetic motor driven by an external magnetic drive actuator.

16. The bone screw device according to any one of claims 1 to 3, in, The planetary gear (6) is a reduction gear.

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