Marking nail for transverse distraction

Abstract

The invention relates to an intramedullary nail (1) for the transverse distraction of a long bone (2), wherein the intramedullary nail (1) comprises a tubular body (3) extending in an axial direction of the intramedullary nail (1), which is at least partially hollow, at least one locking means for locking the tubular body (3) in an end section of the long bone (2), a first inner part (5) and a second inner part (7), which are each arranged to be axially displaceable relative to or together within the tubular body (3), a drive within the tubular body (3) for axially displacing the first inner part (5) relative to the second inner part (7), at least one longitudinal recess (11) of the tubular body (3) and at least one lever mechanism (20) comprising at least one lever element (9, 23, 24) which is configured to be extended and retracted radially from the tubular body (3),wherein the displacement of the first inner part (5) relative to the second inner part (7) causes the at least one lever element (9) to move out of the at least one lateral longitudinal recess (11) of the tube body (3) or to move or retract the at least one lever element (9) into the at least one lateral longitudinal recess (11) of the tube body (3).

Description

Field of the invention

[0001] The present invention relates to an intramedullary medical intramedullary nail for transverse distraction of a long bone, in particular a fully implantable active medical intramedullary nail. State of the art

[0002] Many patients with a pre-existing condition of diabetes suffer from insufficient blood flow to the extremities, particularly in the lower leg area. In critical cases, an adverse course of the disease can lead to amputation. Orthopedics has developed various approaches to correcting extremities. In some cases, it has been found that transverse or transverse distraction of a long bone can significantly improve blood flow to the affected extremity, thereby preventing amputation. This connection is described in the medical literature, for example, in Chen, Y. et al., Proximal Tibial Cortex Transverse Distraction Facilitating Healing and Limb Salvage in Severe and Recalcitrant Diabetic Foot Ulcers, Clin Orthop Relat Res (2020), 478:836-851.

[0003] In orthopedics, devices called external fixators are known for this purpose. They are used, for example, in treatments in which part of the lower leg bone is removed and new bone tissue is generated through transverse distraction, thereby significantly improving the blood flow to the surrounding tissue. The long wearing time of the fixator attached externally to the lower leg greatly increases the risk of infection. In addition, the patient's movement and comfort are severely restricted, there is a risk that the fixator will be moved out of its predetermined position by external impact or pressure forces, which would negatively impact the healing process, the effort required to care for the fixator is high, and there is a risk of infection via the elements (pins) that are arranged both inside and outside the body.

[0004] Intramedullary nails for the axial distraction of a long bone are known, among other things, from EP 2 990 002 A1. US 2002 / 0165544 A1 and US 2017 / 0143387 A1 disclose an intramedullary nail that is fixed to a long bone at its ends by means of an expansion mechanism. This expansion mechanism also includes a narrowly limited radial expansion. In US 2002 / 0165544 A1, sleeves provided with axial slots are arranged on the outside of the core of the intramedullary nail for this purpose. These sleeves can be compressed in their longitudinal direction by means of an axial screw mechanism, thus extending partially radially, similar to a bellows, and clamping the ends of the bone.In US 2017 / 0143387 A1, the intramedullary nail is secured by two radially extendable fixation elements that extend from the outer surface of the nail by sliding against each other, thereby achieving a uniform radial expansion on both sides. The extent of radial expansion of the fixation elements in US 2017 / 0143387 A1 is limited by the diameter of the intramedullary nail.

[0005] A medical device for another surgical use, which serves to reconstruct a missing long bone by means of callus distraction and which has an expansion device for bone expansion, is disclosed in WO 2013 / 023898 A1. The expansion device has a plurality of expansion devices arranged one behind the other in the longitudinal direction. These expansion devices are designed as chambers that are filled with an expansion medium by a pump.

[0006] FR 2 653 006 A1 describes an intramedullary nail with a tubular body and an externally rotatable threaded spindle on which a plurality of clamping elements are arranged. The clamping elements each comprise a first ring body fixed in the longitudinal direction and a second ring body engaging with the thread of the threaded spindle. An expansion element is arranged between the first and second ring bodies. This expansion element moves radially outward through slots in the tubular body upon rotation of the threaded spindle, thereby securing the intramedullary nail to the bone.

[0007] A particular disadvantage of the state-of-the-art devices is that they do not provide a reliable and as gentle a technical solution as possible for transverse distraction. With some known devices, the extent of transverse distraction is essentially limited to the diameter of the intramedullary nail. Some others cannot be adjusted with sufficient precision or must be adjusted intraoperatively or often invasively. Object of the invention

[0008] It is therefore the object of the present invention to provide an intramedullary nail that improves on prior art systems. In particular, the disadvantages of the prior art are to be alleviated or eliminated. The goal is an intramedullary nail that has a simple design and enables reliable transverse distraction using minimally invasive procedures.

[0009] This object is solved by the subject matter of claim 1. Advantageous embodiments are the subject matter of the dependent claims. Summary of the invention

[0010] One aspect of the invention relates to an intramedullary nail for the transverse distraction of a long bone, wherein the intramedullary nail comprises an at least partially hollow tubular body extending in an axial direction of the intramedullary nail, at least one locking means for locking the tubular body in an end section of the long bone, a first inner part and a second inner part, which are each arranged within the tubular body so as to be displaceable relative to one another or with one another in the axial direction, a drive within the tubular body for axially displacing the first inner part relative to the second inner part, at least one longitudinal recess in the tubular body and at least one lever mechanism which comprises at least one lever element which is designed to be extended out of the tubular body and retracted again in the radial direction, wherein the displacement of the first inner part with respect to the second inner part enables it to be moved out or in.Extending the at least one lever element out of the at least one lateral longitudinal recess of the tubular body or moving or retracting the at least one lever element into the at least one lateral longitudinal recess of the tubular body, wherein the drive comprises a motor and a gear.

[0011] The extent of transverse distraction is thus significantly greater than with previous intramedullary nails and is not limited to the diameter of the intramedullary nail. This allows for incremental extension and retraction of the lever mechanism for transverse distraction, without the need for any external elements to be placed on the patient's body. The displacement of the internal components relative to one another by means of a drive can preferably be achieved by pressure or tension. Furthermore, the extent of transverse distraction can be adjusted with the intramedullary nail according to the invention without intervention thanks to contactless energy transfer. The entire transverse distraction procedure is minimally invasive. This provides an active, fully implantable intramedullary nail for transverse distraction, with implantation and explantation possible minimally invasively.

[0012] In embodiments, the at least one lever element can be axially aligned with the longitudinal axis of the intramedullary nail in a retracted position and can be aligned by at least 30°, preferably by at least 45°, more preferably by at least 60°, and most preferably by at least 80° relative to the longitudinal axis of the intramedullary nail in an extended position. This allows for continuous adjustment of the transverse distraction, which the patient can perform themselves if necessary. Multiple lever mechanisms in the intramedullary nail, e.g., two to four, ensure sufficient radial expansion and thus reliable and uniform transverse distraction in the affected areas.

[0013] In preferred embodiments, the drive can be axially supported on the tubular body. This allows for reliable displacement of the first inner part relative to the second inner part.

[0014] In advantageous embodiments, the at least one lever element can be configured to retract upon longitudinal movement of the intramedullary nail without actuating the drive. Accordingly, if the drive fails or the resetting cannot be performed by the drive, the intramedullary nail can still be removed as gently as possible because the two inner parts can be moved relative to each other without the drive. This guarantee of optimal reliability represents a significant advantage over previous devices.

[0015] In a further advantageous embodiment, the second inner part can be formed integrally with the tubular body. This allows for a design with fewer components.

[0016] The lever mechanism can then be retracted and folded using the drive.

[0017] In preferred embodiments, the drive can be embodied as an electric, magnetic, electromagnetic, hydraulic, shape-memory-based, piezoelectric, or pneumatic drive. In particular, such types of drives enable adjustment of the transverse distraction without invasive intervention and / or without physical contact. Furthermore, very small adjustment steps are possible, for example, with an electromechanical linear drive, which is very advantageous for callus distraction and the medical healing process. The aforementioned drive types are inexpensive, reliable, and allow for a simple design.

[0018] In an advantageous embodiment, the drive can comprise a spindle element. Such a design also enables extremely small adjustment steps and offers a reliable, simple assembly of the intramedullary nail.

[0019] In typical embodiments, the first inner part and the second inner part can have a semi-cylindrical shape. This creates a simple structure whose components can be manufactured without problems. It is also possible for the first inner part and the second inner part to have other complementary shapes or cross-sections. In a further exemplary embodiment, the intramedullary nail can have a substantially polygonal cross-section, thus allowing the first inner part and the second inner part to have corresponding polygonal cross-sections or partial cross-sections to allow relative displacement of the two inner parts to one another. Other cross-sectional shapes are possible. It is not absolutely necessary for the cross-sectional area of ​​the first inner part to be the same as the cross-sectional area of ​​the second inner part.

[0020] In particular embodiments, the at least one lever element can be designed as a rocker arm having a slot and a joint device, wherein the joint device is rotatably connected to and axially fixed to the first inner part, and wherein the second inner part has a guide element that is guided in the slot of the rocker arm. The lever mechanism is thus of comparatively simple construction, since the rocker arm only needs to have a slot and a joint device, wherein the joint device can be a pivot pin arranged at one end of the rocker arm, and a guide pin is positively guided in the slot. A rocker arm can be straight, have rounded edges, and have a conically tapered shape. Other embodiments can have curved or irregularly shaped rocker arms. In further embodiments, a reversal of the functional principle described for rocker arms is also possible, i.e.For example, the rocker arm guide is defined by a groove or recess in the first or second inner part. In this way, a design with two rocker arms can also be created, in which the rocker arms have the same shape and are guided synchronously as the inner parts are displaced relative to each other, in the manner of a parallelogram.

[0021] Further typical embodiments include a lever mechanism, wherein the at least one lever element can be designed as a toggle lever. The toggle lever can thus be guided without a slotted hole or guide pin.

[0022] In further typical embodiments, the at least one lever element can be designed as a plurality of articulated chain links, wherein one chain link of the plurality of chain links axially adjoins the first inner part and another of the plurality of chain links adjoins the second inner part, wherein the displacement of the first inner part relative to the second inner part causes at least two chain links to unfold and protrude through a lateral longitudinal recess of the tubular body. This enables radial distraction by at least two chain links, but also by more than two chain links, which are no longer axially aligned in the extended position. The construction with multiple chain links also represents a stable and simple structure.The guide of the chain links can be designed so that the end of one chain link protrudes further from the tubular body in the radial direction than the end of another chain link. It goes without saying that the chain links do not all have to be the same length. The chain links can also have a curved or irregular shape, i.e. they do not necessarily have to be straight. Combinations of straight and irregularly shaped chain links are also possible. The term chain links should also be understood to include flexible belts or push chains with multiple segments. The decisive factor for suitability is elements that, in the broadest sense, perform the function of pivot axes when a group of segments is pushed together.

[0023] In preferred embodiments, the lever elements or chain links can have appropriately designed surfaces on the side facing outward from the tubular body, which enhance the effect of radial distraction. The intramedullary nail itself and its components can typically be made of biocompatible material, such as implant steel, other suitable metal alloys, suitable plastics, and the like. Suitable manufacturing processes also include, for example, 3D printing.

[0024] Typical embodiments can be designed such that one or more plates can be articulated at the free, outwardly directed ends of the rocker arms or lever elements. These plates cover the longitudinal recess(es) when the lever mechanism is retracted and distribute the radial pressure of the lever mechanism over a large area when extended. For example, an embodiment with two rocker arms is conceivable, to each end of which a common elongated plate is articulated. This plate covers a longitudinal recess in the tubular body when retracted and is moved completely radially outward when extended, preferably parallel to the outer surface of the tubular body. Short description of the characters

[0025] Preferred embodiments are described in more detail below with reference to the attached figures, in which: Fig. 1 is a schematic cross-sectional view of a preferred embodiment of the intramedullary nail according to the invention in a first position; Fig. Figure 2 is a schematic cross-sectional view of another embodiment of the intramedullary nail according to the invention in a first position; Fig. Figure 3 is a perspective view of another embodiment of the intramedullary nail according to the invention in a second position; Fig. 4 a schematic cross-sectional view of the intramedullary nail from Fig. 1 is inserted in the first position in a long bone; Fig. 5 a schematic cross-sectional view of the intramedullary nail from Fig. 1 in the second position is inserted into a long bone; Fig. 6 a schematic cross-sectional view of the intramedullary nail from Fig. 1 after leaving the second position; Fig. 7 a schematic cross-sectional view of the intramedullary nail from Fig. 1 is in an extended position; Fig. Figure 8 is a schematic representation of a lever mechanism according to another embodiment in a first position; and Fig. 9 a schematic representation of a lever mechanism from Fig. 8 is in a second position. Detailed description of implementation examples

[0026] In the following description, exemplary embodiments are explained with reference to the figures, with the same reference numerals being used for identical or similar parts. Identical or similar parts may not be explained again in connection with each figure.

[0027] The Fig. 1-7 comprises a substantially cylindrical hollow tubular body 3, in the interior of which a first inner part 5 and a second inner part 7 are accommodated. The first inner part 5 and the second inner part 7 are formed here essentially complementarily as a half-cylinder and extend parallel to each other axially, ie in the longitudinal direction of the intramedullary nail 1. The intramedullary nail 1 has at its lower end, which is Fig. 1 in the lower section, has an end piece 19 which is used to fix the intramedullary nail 1 to a (in Fig. 1) long bone. The end piece 19 has a locking means that can be fastened to the end section of a long bone, for example with a locking bolt that is guided through corresponding openings in the tubular body 3 and through a through-opening 21 in the end piece 19. Bolts known from the prior art for fixing intramedullary nails in bones can be used as locking bolts.

[0028] The cross-section of the intramedullary nail 1, and thus of the base body 3, is circular in the preferred embodiment shown here. Thus, the first inner part 5 and the second inner part 7 can be designed as complementary half-cylinders. The lower end piece 19 also has a substantially cylindrical shape. It should be noted that the intramedullary nail 1 can also have a polygonal cross-section, for example, a triangular, rectangular, square, pentagonal, hexagonal, or octagonal cross-section. An elliptical cross-section is also possible. The inner parts 5, 7 can then also be designed with a corresponding polygonal cross-section.

[0029] In the upper section of the intramedullary nail 1, a gear 8 and, adjacent to it, a motor 10 are arranged, which together form a drive. The gear 8 drives a spindle 12, which is aligned essentially symmetrically to the longitudinal axis 6 of the tubular body 3. In the embodiment shown here, the spindle 12 comprises an external thread that engages with an internal thread in the second inner part 7, so that rotation of the spindle causes the second inner part 7 to move in the axial direction. It is also conceivable for the function to be reversed, i.e., via an axially fixed, driven nut in which a spindle is moved. The power supply and control of the drive can be achieved via an electrical connection, which is not shown in the figures.The electrical connection can be connected to a receiver arranged subcutaneously to enable contactless control and power supply of the intramedullary nail 1 via a control device located outside the patient's body. The power source for the drive can preferably be located outside the patient's body, and in other embodiments, also inside the intramedullary nail.

[0030] As already mentioned above, the intramedullary nail 1 according to the invention can also have other drives with motor 10 and gear 8 than the electromechanical drive shown here.

[0031] In this description, the terms “radial” and “axial” generally refer to the longitudinal axis 6 of the tubular body 3.

[0032] In the middle part, the intramedullary nail 1 of the embodiment shown here has two longitudinal recesses 11, which are aligned substantially parallel to the longitudinal axis 6 and have a width of preferably between 2 mm and 8 mm, even more preferably between 4 mm and 6 mm. The tubular body 3 also has a longitudinal recess 11 in the lower section, which essentially serves for locking and later removal of the intramedullary nail 1 from the long bone, as will be described below with reference to the Fig. 6 and Fig. 7 is explained.

[0033] Also in the central area at the level of the longitudinal recesses or elongated holes 11, the intramedullary nail 1 in the embodiment shown here has two rocker arms 9, which, when used as intended, form the lever mechanism responsible for the transverse distraction. In other words, the rocker arms 9 rotate about a rotation axis in such a way that Fig. 1, that a radial expansion component ensures the transverse distraction because the rocker arm 9 moves out of the longitudinal recess 11. The or each rocker arm 9 has on one side (in Fig. 1 above) has a bore oriented transversely to the longitudinal axis 6 as a rotation axis, through which a pivot pin 15 is guided. The pivot pin 15, in turn, is fixedly arranged on the rocker arm 9 and pivotally connected to the second inner part 7. In a further embodiment, the diameter of the pivot pin 15 is slightly smaller than that of a bore through the rocker arm 9.

[0034] An elongated hole 13 in the rocker arm 9 is formed slightly obliquely to the longitudinal axis 6, with a guide element or guide pin 17 passing through the elongated hole 13 transversely to the longitudinal extent of the elongated hole 13. The guide pin 17 is firmly connected to the first inner part 5.

[0035] The lever mechanism with the rocker arm 9 in the embodiment shown here is actuated by the relative displacement of the first inner part 5 with respect to the second inner part 7. One can see in the upper, middle area of Fig. 1, that a cavity is formed between the first inner part 5 and the second inner part 7 such that it decreases accordingly upon axial movement of the second inner part 7 downwards, triggered by the actuation of the motor 10. The second inner part 7 is thus pushed towards the first inner part 5. Because the pivot pin 15 holds the rocker arm 9 at the base point on the second inner part 7 and the rocker arm 9 is held in the slot 13 by the positive guidance of the guide pin 17, the rocker arm 9 moves in Fig. 1 lower end of the rocker arm 9 out of the longitudinal recess 11. This tilting movement or pivoting movement around the pivot pin 15 is limited by the length of the elongated hole 13 and the distance of the second inner part 7 relative to the first inner part 5. The length of the elongated hole 13 and said distance are coordinated such that a maximum pivoting of essentially 90° of the rocker arm 9 relative to the longitudinal axis 6 is achieved. It is understood that in the illustrated embodiment, the dimensions and distances between the two rocker arms 9 and the inner parts 5, 7 are the same, resulting in a synchronous or coordinated movement. In other embodiments, the lengths of the rocker arms 9 can also be different. Furthermore, it is also possible for the pivot axes of the pivot or guide pins for each rocker arm 9 to differ slightly from one another. This makes it possible to achieve a slightly different tilting direction for different rocker arms 9.

[0036] The continuous adjustment of the drive with motor 10, gear 8, and spindle 12 in both directions allows for very fine adjustment of the radial extension, i.e., the transverse distraction, by means of the rocker arm 9. This allows a patient to adjust the extent of the transverse distraction by externally controlling the motor 10, without the need for intervention by medical personnel or even a surgeon.

[0037] Fig. 2 shows essentially the same intramedullary nail 1 from Fig. 1 in an alternative embodiment, wherein only the lower end differs as follows. Instead of a separate end piece 19 as in the Fig. The embodiment shown in Figure 1 is shown in Fig. 2, the end piece is formed integrally with the first inner part 5. This in turn means that the lower end of the intramedullary nail 1 is secured to the long bone by the first inner part 5 with the corresponding locking means.

[0038] Fig. Figure 3 shows a perspective view of the preferred embodiment of the intramedullary nail 1 according to the invention in a second position in which the rocker arms 9 are extended. It can be clearly seen that the amount of radial projection of the rocker arms 9 is considerably greater than the diameter of the intramedullary nail 1. By appropriately selecting the dimensions of the longitudinal recesses 11 and the rocker arms 9, this amount can be optimized. Furthermore, Fig. 3, the rocker arm(s) 9 do not need to be fully extended or extended. Between the angle of 0°, i.e., the folded position, and the angle of 90°, the fully extended position, any adjustment angle is possible. This allows for very flexible use of the intramedullary nail for transverse distraction.

[0039] The Fig. 4 and Fig. 5 show a schematic cross-sectional view of the intramedullary nail 1 from Fig. 1 in the first or second position in a long bone 2, here a lower leg bone. The long bone 2 is shown in dashed lines and is expressly not part of the present invention. In the lower and upper sections of the long bone 2, the intramedullary nail 1 is fixed in a rotationally secure and axial manner by means of corresponding locking means through through-openings 21. This type of fixation by means of a minimally invasive procedure is known in the art. To prepare for the transverse distraction, an elongated section 4 in the central region of the long bone 2 is removed, e.g., sawn out around its circumference with a fine bone saw. The intramedullary nail 1 lies over the entire length of the elongated section 4 of the long bone 2 in the position of Fig. 4. This represents the starting position before transverse distraction, i.e., the drive within the intramedullary nail 1 has not yet been activated. The first inner part 5 has not yet been displaced relative to the second inner part 7; rather, the original axial offset still exists between them.

[0040] Fig. Figure 5 shows the state after actuation of the drive and thus after or during the transverse distraction. The first inner part 5 and the second inner part 7 are connected by the Fig. 4 and Fig. 5 not shown) drive are moved closer together, whereby the rocker arms 9 move from their axially aligned initial position ( Fig. 4) have moved into the unfolded or extended distraction position. In the embodiment shown here, the rocker arms 9 have each moved radially outward by the same amount through the longitudinal recesses 11. In doing so, they have abutted laterally against the elongated section 4 of the long bone 2 and have moved it transversely outward by a distraction distance, so that a distraction space 14 is created between the outer surface of the tubular body 3 and the inner surface of the elongated section 4. At this point, it should be noted that the representation chosen here is a schematic one.

[0041] In Fig. 6 is a third position of the intramedullary nail 1 of the embodiment of Fig. 1 in the long bone 2 is shown, which is a special one: the intramedullary nail 1 is removed in this position from the long bone 2, axially essentially along the long axis 6. Before the intramedullary nail 1 can be removed, the corresponding locking means at the upper and lower ends of the long bone must be loosened and removed so that axial fixation is no longer present. If the intramedullary nail 1 is now pulled further upwards, e.g. by a surgeon, the rocker arms 9 are initially still extended, i.e. in their distraction position. However, as soon as the upper rocker arm 9 rests against the upper section of the long bone 2, i.e. at the end of the elongated section 4, further movement of the intramedullary nail 1 upwards causes the rocker arm 9 to fold in. This is possible due to the guide in the elongated hole 13.At the same time, the positive guidance in the elongated hole 13 also causes the first inner part 5 to move apart relative to the second inner part 7, because the rocker arm 9 is secured at its base to the second inner part 7 via the pivot pin 15. Consequently, the first inner part 5 moves downward relative to the second inner part 7 and also to the tubular body 3. This, in turn, causes the end piece 19 to be displaced within the tubular body 3 by the first inner part 5.

[0042] This makes it possible for both rocker arms 9 to move completely back into the tubular body 3 and fold in. In particular, the end piece 19 is pressed downwards out of the tubular body 3. This can be achieved because, after the locking means has been released through the through-opening 21 in the end piece 19, there is no longer any axial fixation to the bone and, by pulling the entire intramedullary nail 1 upwards, the end piece 19 can escape into the freed space in the long bone 2. For medical use and for the patient, this means that even without actuating the drive or in the event of a failure or malfunction of the drive, the intramedullary nail 1 can be removed residue-free and essentially problem-free with minimal surgical intervention. Fig. 7 shows schematically the removed intramedullary nail 1, in which the rocker arms 9 are folded in and the end piece 19 protrudes from the bottom of the tubular body 3.

[0043] In the Fig. 8 and Fig. 9 schematically shows an alternative embodiment for the lever mechanism of the intramedullary nail 1 according to the invention. Fig. Fig. 8 shows the lever mechanism 20 in the retracted position, i.e., as it is axially aligned within the tubular body 3 (not shown). A first lever element 23 is articulated to the second inner part 7 via a first pivot axis 26, wherein the first pivot axis 26 is oriented transversely to the longitudinal axis 6 of the tubular body 3. On the side of the first lever element 23 distal from the second inner part 7, a second lever element 24 is articulated via a second pivot axis 27, wherein the second pivot axis 27 is oriented parallel to the first pivot axis 26. The second lever element 24 is in turn articulated to the first inner part 5 via a third pivot axis 28, wherein the third pivot axis 28 is also oriented parallel to the first pivot axis 26. Fig. 8 and Fig. The lever mechanism shown in Figure 9 is a link chain or push chain. Such mechanisms can also be implemented with segmented belts, which also function in tension and not only in thrust. The relative displacement of the two inner parts allows for a pull function in addition to the push principle shown in the figures.

[0044] If the drive of the intramedullary nail 1 now moves the second inner part 7 in the direction of the first inner part 5, which is fixed axially with respect to the tubular body 3, as described above, the first lever element 23 and the second lever element 24 move as shown in Fig. 9 from the axial alignment along the longitudinal axis 6 into a tilted position. Both lever elements 23, 24 move through the longitudinal recess 11 of the tubular body 3 and thereby extend the lever mechanism 20 transversely to the longitudinal axis 6, so that this contributes to the transverse distraction. Fig. 8 and Fig. The principle of the lever mechanism 20 shown in Figure 9 corresponds to a chain link arrangement, whereby the number of lever elements is not limited to two as in the illustration. This results in a multitude of possible designs for such a lever mechanism 20. For example, the lever elements do not necessarily have to be straight. The crucial factor is that the relative displacement of the first inner part 5 with respect to the second inner part 7 results in the lever elements folding out, which then move out of the longitudinal recess of the tubular body in the axial direction. Furthermore, a movement of the inner parts 5, 7 in the opposite direction should cause the lever mechanism 20 to fold in or retract.

[0045] Similar to the Fig. 8 and Fig.9, a toggle lever mechanism is also conceivable in which one end of a first lever element is articulated in the central region of a second lever element. List of reference symbols: 1 intramedullary nail 2 long bones 3 pipe bodies 4 Bone segment / long section 5 first inner part 6 Longitudinal axis 7 second inner part 8 gearboxes 9 rocker arms 10 Engine 11 Longitudinal recess 12 spindle 13 slot 14 Distraction space 15 pivot pins 17 Guide element 19 End piece 20 lever mechanism 21 Passage opening 23 first lever element 24 second lever element 26 first swivel axis 27 second swivel axis 28 third swivel axis

Claims

[1] Intramedullary nail (1) for the transverse distraction of a long bone (2), the intramedullary nail (1) comprising: - an at least partially hollow tubular body (3) extending in an axial direction of the intramedullary nail (1), - at least one locking means for locking the tubular body (3) in an end portion of the tubular bone (2), - a first inner part (5) and a second inner part (7), each of which is arranged within the tubular body (3) so as to be displaceable relative to or with one another in the axial direction, - at least one longitudinal recess (11) of the tubular body (3), - at least one lever mechanism (20) comprising at least one lever element (9, 23, 24) which is designed to be extended and retracted radially from the tubular body (3), - wherein the displacement of the first inner part (5) relative to the second inner part (7) causes the at least one lever element (9) to move out or extend from the at least one lateral longitudinal recess (11) of the tubular body (3) or to move in or retract the at least one lever element (9) into the at least one lateral longitudinal recess (11) of the tubular body (3), characterized by that the intramedullary nail (1) comprises a drive within the tubular body (3) for axially displacing the first inner part (5) relative to the second inner part (7), wherein the drive has a motor (10) and a gear (12). [2] Intramedullary nail (1) according to claim 1, characterized bythat the at least one lever element (9, 23, 24) is aligned axially with the longitudinal axis (6) of the intramedullary nail (1) in a retracted position and is aligned by at least 30°, preferably by at least 45°, more preferably by at least 60° and most preferably by at least 80° with respect to the longitudinal axis (6) of the intramedullary nail (1) in an extended position. [3] Intramedullary nail (1) according to one of the preceding claims, characterized by that the drive is supported axially on the tubular body (3). [4] Intramedullary nail (1) according to one of the preceding claims, characterized by that the at least one lever element (9, 23, 24) is designed to be retracted when the intramedullary nail (1) is moved in the longitudinal direction without actuating the drive. [5] Intramedullary nail (1) according to one of the preceding claims, characterized by that the second inner part (7) is formed integrally with the tubular body (3). [6] Intramedullary nail (1) according to one of the preceding claims, characterized by that the drive is designed as an electrical, magnetic, electromagnetic, hydraulic, shape memory-based, piezoelectric or pneumatic drive. [7] Intramedullary nail (1) according to one of the preceding claims, characterized by that the drive has a spindle element (12). [8] Intramedullary nail (1) according to one of the preceding claims, characterized by that the first inner part (5) and the second inner part (7) have a semi-cylindrical shape. [9] Intramedullary nail (1) according to one of the preceding claims, characterized byin that the at least one lever element is designed as a rocker arm (9) which has an elongated hole (13) and a joint device, wherein the joint device is rotatably connected to and axially fixed to the first inner part (5) and wherein the second inner part (7) has a guide element (17) which is guided in the elongated hole (13) of the rocker arm (9). [10] Intramedullary nail (1) according to one of claims 1 to 8, characterized by in that the at least one lever element is designed as a plurality of chain links (23, 24) which are connected to one another in an articulated manner, wherein one chain link of the plurality of chain links axially adjoins the first inner part (5) and another of the plurality of chain links adjoins the second inner part (7), wherein the displacement of the first inner part (5) relative to the second inner part (7) causes at least two chain links to unfold and protrude through the lateral longitudinal recess (11) of the tubular body (3).

Images