JP2007202843A - Limbs lengthening unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a limbs lengthening unit which can minimize inconvenience in daily life because it is inserted into a bone without being exposed to the outside, which can minimize damage, infection, a scar or the limitation of articular movement, and which is continuously elongated so that osteogenesis can be promoted in a callus lengthening region. <P>SOLUTION: This limbs lengthening unit, which is installed inside the bone so as to lengthen the bone, comprises: an upper hollow structure 21 which is provided in the medullary cavity 11 of the bone, and the upper part of which is fixed to the bone by a fixing means 15; a lower hollow structure 31 which is provided in the medullary cavity 11 of the bone, the lower part of which is fixed to the bone by a fixing means 16, and which is slidably connected to the upper structure 21; a threaded shaft 22 which has a thread formed on an outer peripheral surface; a nut 32 which is meshed with the thread, and which is formed in either of the upper and lower structures 21 and 32; and a motor 26, the output shaft 24 of which is connected to one end of the threaded shaft 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a limb distraction device provided in a bone marrow cavity, and more specifically, when the length of both lower limbs is different due to an acquired cause such as a fracture of a leg, a disease, or various congenital causes, or the height is pathologically. The present invention relates to a limb distraction device for performing limb extension for extending the length of a bone and lengthening a soft tissue when the length of a lower limb needs to be increased.

  Distraction Osteogenesis, the basic concept of limb extension, was devised by Ilizarov, Russia. The principle of neocartilage is to fix the bone firmly with the Ilizarov external fixation device and cut the bone at the fixed intermediate site by osteotomy. At this time, after the periosteum is minimized, 7 to 10 days after the resection, the region where the resection is performed is gradually extended by 1 mm per day using an external fixation device. If 1 mm is divided into four times a day and stretched, the stretched space will be filled with newly formed bone.

  If the principle of neocartilaginous surgery is applied as it is, the length of the site where the folding operation is performed using the existing external fixation device can be extended without fixing with the Ilizarov external fixation device. In particular, when using the Ilizarov external fixation device to stretch the femur, the patient is very inconvenient while the length is extended, and the risk of muscle damage due to the pin is high. The extension technique that was there is preferred.

  The types of external fixation devices used for extremity extension are as follows.

1. Traditional External Fixator, Orthofix, etc.
The traditional external fixation device refers to an external fixation device used before the Ilizarov external fixation device was introduced to the west, and is generally called an external fixation device.

  Depending on the size of the external fixing device, a half pin (Half pin or Schantz screw) with a diameter of 2 to 7 mm is used. Depending on the length and application of the pin, about 1 to 5 cm is formed in a screw shape, and the rear part is smooth. And only the screw portion is inserted into the bone.

  In addition, two or three half pins are inserted into the fracture pieces above and below the fracture part, and the inserted half pins are firmly connected to a tube or rod (Rod) using a clamp (Clamp) and fixed. Then, the length of the bone is extended by moving the clamp part from the tube or load by 1 mm per day.

  In such a traditional external fixation device, when inserting a half pin, the end of the pin stops immediately after penetrating the bone, so that it can be fixed without damage to the skin or muscle in the opposite direction in which the pin is inserted. However, there are disadvantages that are difficult to use for correcting complex deformations.

2. Ring fixator or Ilizarov external fixator
This mechanism, devised by GA Ilizarov, a physician in the Soviet Kurgan region in the 1950s, was introduced to the west by Italian doctors in the early 1980s. It has been proven to be effective in extending the length of bones, correcting complex deformations, and restoring extensive bone defects due to osteomyelitis.

Unlike a general external fixing device half pin, Ilizarov fixed a thin steel wire with a diameter of 1.5 to 1.8 mm to a ring-shaped external fixing device. Device (Small pin fixator) or Ring fixing device (Ring
Also called fixator).

  In the case of the Ilizarov external fixation device, a thin steel wire was used, so that the steel wire penetrated through one skin and passed through the bone to the other side in order to obtain a fixing force. 90-130 kg tension was applied to the ring and fixed to the ring. Therefore, the thin steel wire used in the Ilizarov external fixing device is called a transfixing wire.

  In addition, because the Ilizarov external fixation device uses a thin through-steel wire, it can be used effectively even in the case of fractures around joints where the size of the fracture piece is small and it is difficult to obtain the fixation force with an external fixation device that uses a half pin. Can do.

  On the other hand, when using the Ilizarov external fixation device, it is inevitable that the penetrating steel wire penetrates the muscle, and there is a problem that restricts the movement of the adjacent joint, and there is a risk of damaging important parts such as blood vessels and nerves. There are many.

  Therefore, all the disadvantages of the general external fixing device and Ilizarov external fixing device were complemented, and a new device was devised by gathering the advantages of each. A typical example is the Rancho's Modification of Ilizarov Frame.

3. H Fixator External Fixator
This is an external fixing device in which the ring of the Ilizarov external fixing device is connected to the tube used in the external fixing device and half pins or through steel wires are mixed as required. It is mainly used to treat fractures around the joint, such as the proximal or distal part of the bone.

  When using such an H-fixator external fixation device, use a steel wire to fix small fractures around the joint and use a half pin for the trunk of the bone, so avoid unnecessary muscle damage. There is an advantage that can.

4). Rancho's Modification of Ilizarov Frame
Since the half pin used in a general external fixation device is connected to the Iliza Rofu ring and fixed, the penetration steel wire and the half pin can be freely selected as necessary. Was greatly improved, and nerve and blood vessel damage was also reduced.

  However, when using an existing external fixation device or Ilizarov external fixation device for extremity extension, a mechanism that penetrates the skin and bone from the outside is included, so infection is inevitably caused and 8 to 20 penetrates the skin. Scars that can not be solved by plastic surgery occur in the skin of the iron wire part of the wire, and the penetrating iron wire passes through the muscles and causes pain, restricting joint movement and inducing long-term joint stiffness There is.

  In general, it takes 3 to 12 months to extend the limbs, so it is necessary to wear an external fixation device for a long time, which causes considerable inconvenience in wearing clothes and daily life.

  Accordingly, the present invention was invented to solve the above-described problems, and provides a limb distraction device that can be inserted into a bone and not exposed to the outside, thereby minimizing inconvenience in daily life. That is the purpose.

  In addition, the present invention has been invented to solve the above-mentioned problems, and since the cutting is performed through the mechanism insertion site without an external wound, the periosteum damage, infection, scar, or joint It is an object of the present invention to provide a limb distraction device that can minimize the limitation of movement.

  In addition, the present invention has been invented to achieve the above-described object, and provides a limb distraction device capable of continuously distracting and promoting bone formation to a distraction site. For that purpose.

  In order to achieve such an object, the present invention provides a limb distraction device for extending the length of a bone that is installed inside a bone, provided in the bone marrow cavity (11) of the bone, and Is provided in the bone marrow cavity (11) of the bone, and a lower stage is attached to the bone by the fixing means (16). A hollow lower structure (31) fixed and slidably coupled to the upper structure (21); a screw shaft (22) having a thread formed on an outer peripheral surface thereof; and meshing with the thread; The nut (32) formed in any one of the upper structure (21) and the lower structure (32) and the output shaft (24) are connected to one end of the screw shaft (22). Limb distraction characterized by including a motor (26) To provide a location.

  In the above description, the reference numerals in parentheses attached to the constituent elements are merely shown as examples of corresponding constituent elements in the embodiments and drawings described below for easy understanding. It is not limited to.

  As described above, according to the present invention, since it is inserted into the bone and is not exposed to the outside, there is an effect of providing a limb distraction device that can minimize inconvenience in daily life.

  In addition, according to the present invention, since the cutting is performed through the mechanism insertion site without an external wound, there is an effect of providing a limb distraction device that can minimize periosteal damage, infection, scar, or joint movement limitation.

  Moreover, according to this invention, there exists an effect which provides the limb distraction apparatus which can be distracted continuously and can promote bone formation to a callus distraction site | part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that the same reference numerals are given to the same components as much as possible even if they are displayed on other drawings by adding reference numerals to the components of each drawing. Don't be. In the description of the present embodiment, when it is determined that a specific description of a related known configuration or function can obscure the gist of the present invention, a detailed description thereof will be omitted.

  FIG. 1 is a longitudinal sectional view showing a form in which a limb distraction device according to a preferred embodiment of the present invention is provided in a bone marrow cavity of a bone, and FIG. 2 shows the operation of the limb distraction device according to a preferred embodiment of the present invention. It is a longitudinal cross-sectional view which shows a form.

  As shown in FIGS. 1 and 2, the limb distraction device according to a preferred embodiment of the present invention includes an upper structure 21, a lower structure 31, a screw shaft 22, a nut 32, a motor 26, a controller 28, a wireless device. An energy receiver 29, a reverse rotation prevention device 23, an output shaft 24, and a stopper 22a are included.

  The upper structure 21 is provided in the bone marrow cavity 11 of the bone 10 and has a hollow shape whose upper stage is fixed to the bone 10 by the fixing means 15. Although a screw is preferably used as the fixing means 15, it is not limited to this.

  The lower structure 31 is provided in the bone marrow cavity 11 of the bone 10 and has a hollow shape whose lower stage is fixed to the bone 10 by the fixing means 16 and is slidably connected to the upper structure 21. Although a screw is preferably used as the fixing means 16, it is not limited to this.

  Since the upper structure 21 and the lower structure 31 must be able to slide relative to each other, the shape of each cross section is any one of a circular shape, an elliptical shape, a polygonal shape, and a partially bent shape. It is preferable to consist of a shape.

  The screw shaft 22 has a thread formed on the outer peripheral surface, and a nut 32 is engaged with the thread. Further, the upper stage of the screw shaft 22 is connected to the output shaft 24 of the motor 26 to receive a rotational force from the motor 26, and a stopper 22a is formed on the lower stage.

  The nut 32 surrounds the outer peripheral surface of the screw shaft 22 and meshes with the screw thread to be formed in the upper stage of the lower structure 31.

  The motor 26 is a device that rotates the screw shaft 22, and is connected to the upper stage of the screw shaft 22 via the output shaft 24. On the other hand, the motor 26 is preferably provided inside the upper structure 21, but is not limited thereto.

  On the other hand, the drive of the motor 26 is controlled by the controller 28. That is, an encoder 27 that is formed on the opposite side of the output shaft 24 of the motor 26 and that measures the rotational angle and the rotational speed of the motor 26 magnetically or optically is rotated by the motor 26. If the number is sensed and the sensed value is transmitted to the controller 28, the controller 28 controls the rotation speed of the motor 26 based on the transmitted value. Moreover, if the rotation speed of the motor 26 is controlled, the sliding speed of the lower structure 31 is controlled, and finally the distraction speed of the bone 10 is controlled.

  The wireless energy receiver 29 is a device for converting energy using a change in the magnetic field due to a change in the external electric field in the radio wave region and supplying power directly to the motor 26 or charging an internal battery. It is. If necessary, the wireless energy receiver 29 can be positioned between the bone 10 and the skin.

  The reverse rotation prevention device 23 is a device that is provided between the screw shaft 22 and the output shaft 24 and prevents reverse rotation of the motor 26 due to an excessive external force applied in the vertical direction of the screw shaft 22.

  3a and 3b are cross-sectional views each showing a reverse rotation prevention device.

  3a and 3b, the reverse rotation prevention device 23 includes a reverse rotation prevention gear 50 formed on the outer peripheral surface of the output shaft 24 and a clutch 40 that contacts the gear teeth of the reverse rotation prevention gear 50. .

  When the output shaft 24 rotates in the counterclockwise direction and then attempts to rotate in the clockwise direction by an external force, the gear teeth of the reverse rotation prevention gear 50 are caught by the clutch 40, so that the reverse rotation is prevented.

  The speed reducer 25 is connected to the motor 26 to reduce the rotational speed of the motor 26 and increase the output torque (Torque) of the output shaft 24. As the speed reducer 25, a known device using various gears can be used.

  The stopper 22 a is a device for restricting the lower structure 31 from sliding beyond a certain distance, and is formed in the lower stage of the screw shaft 22. Therefore, even if the lower structure 31 slides to the maximum extent, the nut 32 formed on the upper stage of the lower structure 31 comes into contact with the stopper 22a, so that no further sliding is possible.

  The operation of the limb distraction device according to a preferred embodiment of the present invention having the above-described configuration will be specifically described as follows.

  When the motor 26 is driven at a constant speed by the controller 28, the screw shaft 22 is rotated by the output shaft 24 and the speed reducer 25.

  When the screw shaft 22 rotates, the nut 32 moves linearly. However, since the output shaft 24 rotates only in one direction by the reverse rotation preventing device 23, the nut 32 also moves linearly only in one direction. In the case of this embodiment, it is for extending the length of the bone 10, so the nut 32 moves downward.

  When the nut 32 starts to move, the lower structure 31 having the nut 32 on the upper stage moves along the inner peripheral surface of the upper structure 21. Eventually, the length of the bone 10 is increased at a constant speed by such a linear motion of the lower structure 31.

  The above description is merely illustrative of the present invention, and various modifications can be made without departing from the essential characteristics of the present invention as long as they have ordinary knowledge in the technical field to which the present invention belongs. And variations are possible. Therefore, the embodiments disclosed in the present specification are not intended to limit the present invention, but are for explanation, and the scope of the technical idea of the present invention is not limited by such embodiments. The protection scope of the present invention should be construed according to the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the right of the present invention.

It is a longitudinal cross-sectional view which shows the form with which the extremity extension apparatus which concerns on preferable embodiment of this invention was provided in the bone marrow cavity of a bone. It is a longitudinal cross-sectional view which shows the form which the limb distraction apparatus which concerns on preferable embodiment of this invention act | operates. It is a cross-sectional view showing a reverse rotation prevention device. It is a cross-sectional view showing a reverse rotation prevention device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bone 11 Bone marrow cavity 12 Fracture part 15,16 Fixing means 21 Superstructure 22 Screw shaft 22a Stopper 23 Reverse rotation prevention device 24 Output shaft 25 Decelerator 26 Motor 27 Encoder
28 Controller 29 Wireless energy receiver 31 Substructure 32 Nut 40 Clutch 50 Reverse rotation prevention gear

Claims (9)

In a limb distraction device for extending the length of the bone installed inside the bone,
A hollow superstructure provided in the bone marrow cavity of the bone and having an upper stage fixed to the bone by a fixing means;
A hollow lower structure provided in the bone marrow cavity of the bone and having a lower stage fixed to the bone by a fixing means and slidably connected to the upper structure;
A screw shaft having a thread formed on the outer peripheral surface;
A nut that meshes with the thread and is formed on any one of the upper structure and the lower structure;
A motor having an output shaft coupled to one end of the screw shaft;
Limb distraction device characterized by comprising:   The cross-sectional shape of the upper structure and the lower structure may be any one of a circular shape, an elliptical shape, a polygonal shape, and a shape having a partial bend. The limb distraction device according to 1.   The limb distraction device according to claim 1, wherein power for driving the motor is supplied from a battery and / or a wireless energy receiver.   The limb distraction device according to claim 1, further comprising an encoder that senses the rotation speed of the motor.   The limb distraction device according to claim 4, further comprising a controller that controls driving of the motor based on the signal after receiving a signal from the encoder.   The limb distraction device according to claim 2, wherein a reverse rotation prevention device is provided between the output shaft and the screw shaft. The reverse rotation prevention device is
A reverse rotation prevention gear formed on the outer peripheral surface of the output shaft;
A clutch in contact with the gear teeth of the reverse rotation prevention gear;
The limb distraction device according to claim 6, wherein the limb distraction device is formed.   The limb distraction device according to claim 7, wherein the motor includes a speed reducer.   The limb distraction device according to claim 8, wherein a stopper is formed at the other end of the screw shaft.

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