JP2009542272A - Callus extension device - Google Patents

Abstract

  First and second callus extension elements (12, 13) that can be fixed to a first piece and a second piece, respectively, to be pulled apart, and in use, the first piece and the second piece, First and second callus extension elements (12, 13) that are relatively movable and at least one magnetic element that is mounted so as to be rotatable under the influence of an external magnetic field (11) and conversion means (14) provided to cause relative movement of the first and second callus extension elements (12, 13) when the at least one magnetic element (11) rotates. ), And the relative movement of the first and second callus extension elements (12, 13) is in the direction in which the first and second callus extension elements (12, 13) are separated from and close to each other. Possible in any direction That, distraction device (10).

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to a callus extension device. In particular, it relates to an osteosynthesis device for osteosynthesis for extending bone, but is not limited thereto.

Background Traditionally, bone extension involves folding the bone and attaching a pin to each of its fragments. The pins typically extend through the skin and are connected via a threaded callus extension bar device. The callus extension device is operated so as to increase the distance between the bone fragments by moving the pins stepwise so as to be separated from each other. In general, the pulling is performed for 10 to 20 days with 1 mm per day. When the bone fragments are moved apart, new bone is generated in an attempt to fill the gap. In this way, the bone can be extended by the gradual separation of the initial bone fragments. While this device can provide sufficient bone detachment, the puncture required for the pin to penetrate the skin results in increased skin scars and risk of infection.

  Consequently, a callus extension device that is completely implantable under the skin and thus does not require a connecting element that projects through the skin is desired. However, there is a problem of how to control and effectively operate the callus extension device.

  Previous proposals for fully implantable callus extension devices include motor drive elements, pneumatic pumps and pressurized gas chambers, which can be magnetically coupled to external actuators or other wireless couplings Can be operated through. A common feature of such devices is that they have some complexity, which in turn makes the device unreliable, cumbersome and expensive. Not only are these devices prone to operational failure, they may increase the risk of infection due to the nature of the materials contained within the devices. For example, some of these devices include batteries that leak harmful chemicals into the body. Another disadvantage of these devices is that their complexity is largely sized. This will not be a problem when dealing with large bones such as the arms and legs, but the device is appropriately miniaturized for use with small bones such as the jaw bone and skull. It will prevent that.

  Applicant's PCT / GB99 / 01039 discloses a mechanical callus extension device, particularly for use with small bones. In this apparatus, the internal magnet can move linearly within the housing under the influence of a linear external magnetic field. The linear motion of the magnets therein has been converted into a linear separation of the first and second callus extension elements via a coupling means such as a ratchet. As a result, the bone fragments attached to the first and second callus extension elements were linearly separated. Although this device was able to transmit its required force and incremental gradual separation, it lacked a certain mechanical strength that affected reliability. In addition, since the device is designed to operate in only one direction, even if the patient felt pain, for example, the gap between the bone fragments could not be reduced after extension.

  The present invention is directed to providing a callus extension device that is simplified but robust in view of the problems discussed above.

DESCRIPTION OF THE INVENTION According to the present invention, first and second callus extension elements that can be respectively fixed to a first piece and a second piece to be pulled apart, and in use, the first piece and the second piece First and second callus extension elements that are relatively movable, at least one magnetic element that is mounted to be rotatable under the influence of an external magnetic field, and at least one of said at least one Translating means for causing relative movement of the first and second callus extension elements when one of the magnetic elements rotates, wherein the relative movement of the first and second callus extension elements is There is provided a callus extension device characterized in that the first and second callus extension elements can be separated and approached.

  The above structure has the advantage that it can be easily manipulated when an external magnetic field is applied. This means that there is no part required to penetrate the skin during the detachment period and that the device will be completely implanted under the patient's skin. Thus, both the amount of scar and the risk of infection are reduced. Furthermore, since the device includes a simple structure, it is less likely to fail the operation than a more complex device and can be easily scaled to accommodate different size applications. Thus, the device according to the present invention may be used for pulling away small bones such as jaws or skulls, as well as long bones in the legs or arms, for example. A further advantage is that the simplicity of the device makes it relatively inexpensive and easy to manufacture. Also, because the operation is quick and simple, the separation itself does not need to be performed by surgery, for example it may be performed by a nurse with little skill, and is therefore less expensive than surgery. Furthermore, the device can be operated in both directions, which has the advantage that if the patient feels severe pain after the pulling motion, the pulling may be reversed.

  Finally, in the device according to the invention, the separation is caused by the rotational movement of the (internal) magnetic element, which makes it possible to reduce the space compared to the case where linear movement is employed and thus to make the device more compact. There is an effect.

  Preferably, the converting means includes a threaded bar, and when the threaded bar is rotated about its longitudinal axis, the first callus extension element is relative to the threaded bar. Held in place, the second callus extension element is movable longitudinally along the length of the threaded bar.

  Preferably, the at least one magnetic element is axially coupled to the threaded bar and is rotatable about its longitudinal axis.

  In one embodiment, the at least one magnetic element is incorporated within the threaded bar. Alternatively, the at least one magnetic element may be constructed by forming the threaded rod itself from a magnetic material. These particular embodiments are advantageous in that they reduce the number of individual parts, simplify the operation and structure of the device, and allow a reduction in device size.

  In yet another embodiment, the at least one magnetic element is coupled to the threaded rod and is rotatable about an axis parallel to the axis of the threaded rod. Preferably, the converting means further includes a force increasing means. Preferably said force increasing means comprises a gear coupling between said at least one magnetic element and said threaded bar.

  In one embodiment, the at least one magnetic element is rotatable within a stationary sheath. This has the advantage of reducing the friction caused by the magnet as it rotates.

  Preferably, each of the first and second callus extension elements includes a movable mounting plate for securing the first and second callus extension elements to the first piece and the second piece. This feature provides a variety of locations for attachment to the piece. Preferably, the movable attachment plate is attached to each of the first and second callus extension elements via ball bearing joints.

Preferably, the callus extension device is configured to be fully implanted under the patient's skin.
Preferably, the callus extension device is still configured to be embedded after the required detachment.

  Alternatively, the callus extension device is configured to be removed from the patient after the required detachment has occurred.

  Preferably, the callus extension device further includes detection means for detecting an amount of relative movement between the first callus extension element and the second callus extension element.

Particular embodiments of the present invention are illustrated in the accompanying drawings.
1 is a schematic view (not an accurate measure) of a callus extension device in a first position, according to one embodiment of the present invention. FIG. 1B is a schematic view of the callus extension device of FIG. 1A in a second position. FIG. FIG. 6 is a schematic view (not an accurate measure) of a callus extension device in a first position, according to a second embodiment of the present invention. 2B is a schematic view of the callus extension device of FIG. 2A in a second position. FIG. 1 is a cross-sectional view showing the use of a callus extension device according to the present invention for pulling away a patient's jawbone. It is a figure which shows rotation of the magnet inside the callus extension apparatus which concerns on this invention under the influence of an external rotating magnetic field. It is a figure which shows rotation of the magnet inside the callus extension apparatus which concerns on this invention under the influence of an external rotating magnetic field. It is a figure which shows rotation of the magnet inside the callus extension apparatus which concerns on this invention under the influence of an external rotating magnetic field. It is a figure which shows the structure different from the external magnetic actuator shown by FIG. 4A-FIG. 4C. It is a figure which shows the different structure of the magnet inside the callus extension apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the callus extension apparatus which concerns on the 2nd Embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, a callus extension device 10 according to a first embodiment of the present invention is shown in FIGS. 1A and 1B. The callus extension device 10 includes a first callus extension element 12 and a second callus extension element 13, both of which are attached to a threaded bar 14. The first callus extension element 12 has an internal hole (not shown) through which the threaded rod 14 is fed, the internal hole being the length of the bar 14 from which the first callus extension element 12 is threaded. Allow the threaded rod 14 to rotate in its hole without being moved longitudinally along. The second callus extension element 13 also has a hole (not shown). However, in this case, when the threaded rod 14 is screwed into the hole, the threaded rod 14 rotates in the axial direction, whereby the second callus extension element 13 is threaded. The hole is threaded to move longitudinally along the length of. Both the first and second callus extension elements 12, 13 include a mounting plate 15 having an opening 16 for receiving mounting means such as screws (not shown) in use. The two sliding rods 17 are arranged parallel to the threaded rod 14, are radially opposed to the threaded rod 14, and are spaced from the threaded rod 14. One end of each sliding bar 17 is attached to the first callus extension element 12, and the other end of each sliding bar 17 penetrates a respective hole (not shown) in the second callus extension element 13. Has been. The magnetic element 11 is axially aligned with the threaded rod 14 and is connected to one end of the threaded rod 14. In the particular callus extension device 10 shown, the magnetic element 11 is connected to a bar 14 threaded at the end adjacent to the first callus extension element 12.

  In use, the callus extension device 10 may be completely implanted in the patient's body. The first callus extension element 12 is attached to the first bone fragment by using a screw through its opening 16. Similarly, the second callus extension element 13 is attached to the second bone fragment by using a screw through its opening 16. Then, an external magnetic field is applied in the vicinity of the callus extension device 10. As shown in FIG. 1A, the external magnetic field may be applied by a rotary magnetic actuator 20 connected to a power source 21. When the external magnetic actuator 20 is rotated, the magnetic actuator 20 attracts the magnetic element 11 in the callus extension device 10 and also rotates the magnetic element 11. Since the magnetic element 11 is connected to the threaded bar 14, the threaded bar 14 is rotated by the rotation of the magnetic element 11. This repetition causes the second callus extension element 13 to move longitudinally along the rod 14 threaded relative to the first callus extension element 12. Thus, depending on the direction of rotation induced by the external magnetic field, the second callus extension element 13 is moved away from the first callus extension element 12 or the first callus extension element. 12 is moved in the direction close to 12. Therefore, the magnetic element 11 is rotated in a direction to move the second callus extension element 13 away from the first callus extension element 12 to cause the attached bone fragments to be pulled apart. Conveniently, the external magnetic actuator 20 is calibrated so that the operator can determine the degree of rotation required to produce the desired distance between the bone fragments. Generally, bone fragments are pulled apart by about 1 mm per day for about 10 days. Further separation will occur about a year later.

  A callus extension device 30 according to the present invention having another structure is shown in FIGS. 2A and 2B. Components similar to those shown in FIGS. 1A and 1B have corresponding reference numerals. The main difference between the callus extension device 30 and the above-mentioned callus extension device 10 is that the magnetic element 11 is axially parallel to the threaded bar 14 and hence the above-mentioned callus extension device 10. It replaces one of the sliding rods 17 in FIG. With this structure, there is an effect that the callus extension device 30 can be further miniaturized, and further, it is possible to employ force increasing means by a gear coupling method. The first callus extension element 12 is positioned at one end of the callus extension device 30. Extending from one side of the first callus extension element 12 is a fixed sliding bar 17, a rotatable threaded bar 14, and a rotatable magnetic element 11. As before, the second callus extension element 13 has a threaded hole (not shown) for receiving the threaded rod 14 and pairing with the thread of the threaded rod 14. The second callus extension element 13 also has respective holes (not shown) through which the sliding rod 17 and the magnetic element 11 are passed and slid therein. The ends of the sliding rod 17, the threaded rod 14, and the magnetic element 11 opposite to the first callus extension element 12 are connected to an end bracket 32. Located adjacent to the end bracket 32 at each end of the threaded bar 14 and the magnetic element 11 is a gear element 31 that engages each other.

  Similarly to the above, in use, the callus extension device 30 is attached to the first and second bone fragments via the attachment plates 15. When an external magnetic field is applied, the magnetic element 11 rotates. As a result, the gear element 31 arranged on the magnetic element 11 also rotates. In doing so, the gear element 31 arranged on the magnetic element 11 engages the gear element 31 arranged on the threaded bar 14, and therefore the threaded bar 14 also rotates. As a result, as the threaded rod 14 rotates, the second callus extension element 13 is moved along the longitudinal direction of the threaded rod 14. In this way, the second callus extension element 13 is moved in a direction away from the first callus extension element 12 or moved in a direction close to the first callus extension element 12 and attached. The bone fragments are moved away from each other or close to each other.

  As can be imagined, differently sized gear elements 31 may be employed on the threaded bar 14 and the magnetic element 11 to produce increased or reduced forces.

  FIG. 3 illustrates the use of a callus extension device 40 according to the present invention, which has been applied to dilate a patient's jawbone 41. Thus, the callus extension device 40 is implanted through the incision 42 in the gum 43 in the patient's mouth. The patient's cheek 44 can conceal the resulting gum 43 wound, thereby avoiding external wounds. As shown, the rotating external magnetic actuator 20 can be brought closer to the callus extension device 40 to produce the desired pulling action. In the example shown, the external magnetic actuator 20 is approximately 8 mm away from the callus extension device 40 in use.

  As illustrated, the external magnetic actuator 20 is disposed on one side of the callus extension device 40. This is referred to as asymmetric magnetic coupling because the external magnetic field is not required to be symmetric around the callus extension device 40. The symmetry of the external magnetic field around the callus extension device 40 applies to the typical callus extension device used for long bones such as those in the legs and arms. The asymmetric magnetic coupling is another factor that favors the use of the present callus extension device 40 with small bones such as the jaw. A further application of the callus extension device 40 of the present invention relates to closing the skull hole.

  4A to 4C show how the external magnetic field affects the magnetic element 11. Thus, the rotary external magnetic actuator 20 is shown with respect to a cross section adjacent to the magnetic element 11. In a particular example, the rotary external magnetic actuator 20 includes four permanent magnets 22 that are equally spaced around a rotary drum 23. In other embodiments, more magnetic elements 22 may be used. Each permanent magnet 22 and the north pole of the magnetic element 11 are indicated by arrows. Some of the magnetic field lines 24 generated by the permanent magnet 22 are also shown. Accordingly, as shown in FIGS. 4A, 4B, and 4C, the magnetic element 11 in the callus extension device 10 maintains alignment with the applied external magnetic field 24 when the external magnetic actuator 20 is rotated. Rotate to. When the drum 23 is continuously rotated, the magnetic element 11 is completely rotated with respect to the half rotation of the drum 23. As a result, when the external magnetic actuator 20 completes one rotation, the magnetic element 11 rotates twice. As described above, the number of rotations generated in the internal magnetic element 11 per rotation of the external drive 20 is determined by the number of magnets 22 (or poles) in the external drive 20.

  A structure different from the external magnetic actuator 20 shown in FIGS. 4A to 4C is shown in FIG. Thus, rather than the magnet 22 being oriented with either pole facing the center of the drum 23, the magnet 22 shown in FIG. 5 is in the tangential direction of the drum 23, although each pole is in a staggered direction. Aligned and oriented. In any case, a rotating magnetic field 24 is generated around the drum 23, and when the drum 23 rotates, the magnetic element 11 in the callus extension device 10 is aligned with the applied magnetic field 24. Rotate for.

  FIG. 6 shows another structure of the magnetic element 11. In this way, the two opposing magnets 50 and 51 are arranged adjacent to each other, oriented so that their poles attract each other.

  FIG. 7 shows a cross-sectional view of a callus extension device 60 according to an embodiment of the present invention having still another structure. Components similar to those shown in FIGS. 1A and 1B have corresponding reference numerals. The main difference between the callus extension device 60 and the callus extension device 10 described above is that the magnetic element 11 is incorporated into the threaded bar 14. This structure has the effect of providing a sealed magnetic element 11 and at the same time making the callus extension device 60 more compact. As described above, the first callus extension device 12 is positioned at one end of the callus extension device 60. Extending from one side of the first callus extension element 12 is two fixed sliding rods 17 and a rotatable threading in which the magnetic element 11 is embedded along its length. It is the stick 14 made. As before, the second callus extension element 13 has a threaded hole (not shown) for receiving the threaded rod 14 and pairing with the thread of the threaded rod 14. The second callus extension element 13 also has respective holes (not shown) through which the sliding rod 17 and the magnetic element 11 are passed and slid therein. The ends of the sliding bar 17 and the threaded bar 14 opposite to the first callus extension element 12 are connected to an end fixing bracket 32.

  In use, the callus extension device 60 operates in substantially the same manner as the callus extension device 10 described above in connection with FIGS. 1A and 1B.

  The length of the magnetic element 11, the distance from the magnetic actuator 20 outside the magnetic element 11, and the thread pitch of the threaded bar 14 determine the pulling force provided by the callus extension device according to the present invention. Preferably, the callus extension device provides a pulling force of about 2 kg.

  Conveniently, the thread pitch of the threaded bar 14 is small (in other words small steps) in order to move each callus extension element very slowly and stepwise.

  In some embodiments, the magnetic element 11 may be disposed within a sheath (not shown) to reduce friction caused by the magnetic element 11 as the magnetic element 11 rotates. In order for the callus extension device to be used in the body, the sheath and each rod are preferably manufactured from stainless steel.

If desired, one or more callus extension devices may be used for bone removal.
The external magnetic field may be generated by a permanent magnet or an electromagnet. The external magnetic field may be a pulsed external magnetic field. This would be particularly useful to obtain a higher magnetic field, for example to initiate the bone removal process. This is because after the callus extension device is implanted, the patient is typically left for 4-5 days to recover from the surgery. At this time, each detached piece of bone may be partially healed, so extra momentum of energy may be required to initiate the bone removal process.

In the case of jaw or skull detachment, an external magnetic actuator 20 may be provided inside the removable helmet to assist in positioning the actuator 20 in proximity to the implanted callus extension device 40. good.
Still other embodiments of callus extension devices may be devised in accordance with the present invention.

Claims (17)

First and second callus extension elements capable of being fixed to the first piece and the second piece, respectively, to be pulled apart, in order to cause the first piece and the second piece to be separated in use. First and second callus extension elements that are relatively movable;
At least one magnetic element mounted to be rotatable under the influence of an external magnetic field;
Conversion means provided to cause relative movement of the first and second callus extension elements when the at least one magnetic element rotates;
The relative movement of the first and second callus extension elements can be performed in either a direction in which the first and second callus extension elements are separated or a direction in which they are close to each other. Callus extension device.   The callus extension device according to claim 1, wherein the converting means includes a threaded bar.   When the threaded rod is rotated about its longitudinal axis, the first callus extension element is held in place relative to the threaded bar, and the second callus extension element is 3. A callus extension device according to claim 2, wherein said device is movable longitudinally along the length of said threaded bar.   The callus extension device according to claim 2 or 3, wherein the at least one magnetic element is axially connected to the threaded rod and is rotatable about an axis in the longitudinal direction.   The callus extension device according to claim 2 or 3, wherein the at least one magnetic element is incorporated in the threaded bar.   The callus extension device according to claim 2 or 3, wherein the threaded rod is formed of a magnetic material to constitute the at least one magnetic element.   The callus extension according to claim 2 or 3, wherein the at least one magnetic element is coupled to the threaded bar and is rotatable about an axis parallel to the axis of the threaded bar. apparatus.   The callus extension device according to any one of claims 1 to 7, wherein the conversion means further includes a force increase means.   8. The claim 8 when dependent on any one of claims 2-7, wherein the force increasing means comprises a gear coupling between the at least one magnetic element and the threaded bar. The callus extension device described.   The callus extension device according to claim 1, wherein the at least one magnetic element is rotatable inside a stationary sheath.   Each of the first and second callus extension elements includes a movable mounting plate for securing the first and second callus extension elements to the first piece and the second piece. The callus extension device according to any one of claims 1 to 10.   The callus extension device according to claim 11, wherein the movable attachment plate is attached to each of the first and second callus extension elements via ball bearing joints.   The callus extension device according to any one of claims 1 to 12, wherein the device is configured to be completely embedded under the skin of a patient.   The callus extension device according to any one of claims 1 to 13, wherein the callus extension device is configured to be embedded and remain even after a desired separation is performed.   The callus extension device according to any one of claims 1 to 13, wherein the device is configured to be removed from a patient after a desired separation has been performed.   The detection means for detecting the amount of relative movement between the first callus extension element and the second callus extension element, further comprising: The callus extension device described.   A callus extension device substantially as described above and shown in reference to any one of FIGS. 1A and 1B, 2A and 2B, and FIG.

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