JP2008067966A - External wound fixing device for animals - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an animal's external wound fixing device that stabilizes its pelvis while securing the movable range of its hind legs. <P>SOLUTION: The wound fixing device is provided with left and right pins 3, 3 respectively inserted into the left and right thighbones, left and right holding parts 11, 11 for holding the left and right pins 3, 3, and an arm 21 for connecting these holding parts 11, 11 together. The pins 3, 3 inserted into the left and right thighbones are held with the holding parts 11, 11. The interval between the holding parts 11, 11 is fixed with the arm 21, and this can reduce the load applied to the pelvis located between the left and right thighbones. Also because of the structure where pins 3, 3 are inserted into thighbones inside the body, and the other holding parts 11, 11 and the arm 21 are installed outside the body, the incision necessary for the device installation or removal operation during and after the therapy can be small and minimally invasive, and a sufficient initial security is assured even with thin thighbones. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an animal external fixation device that stabilizes the pelvis while ensuring the range of motion of the animal's hind legs.

  There are very few biomechanical studies on small animals such as dogs and cats that are often kept as pet animals. Since the treatment of the part is postponed, there are very few examples of research and development of fracture repair / correction technology and devices for small animals.

  Therefore, the clinical site's demand for these developments is extremely strong, and the momentum to tackle research is increasing, but no remarkable results have been obtained. In particular, a dedicated fracture correction and repair window suitable for small animals Since there is no external fixing device, it is the present condition.

In many cases, small animals fall along with traffic accidents, futons dried on the handrails of desks and verandas, etc., resulting in pelvic fractures and femoral fractures with internal organ rupture. In such a case, a fixing plate (for example, Patent Document 1) and an external fixation device (for example, Patent Document 2) are used for fractures of a normal-sized animal. There are problems such as incurring secondary fractures in the law, or simply miniaturizing the size, but small animals cannot function functionally.
JP 2002-345836 A JP 2004-141403 A

  Therefore, an object of the present invention is to provide an animal external fixation device that can stabilize the pelvis while ensuring the range of motion of the animal's hind legs.

  The invention described in claim 1 includes left and right pins respectively inserted into the left and right femurs, left and right holding portions for holding the left and right pins, and a connecting member for connecting the left and right holding portions. .

  According to a second aspect of the present invention, the pin is rotatably held by the holding portion.

  According to a third aspect of the present invention, the holding portion is connected to the connecting member so that the position thereof can be adjusted.

  According to the configuration of claim 1, since the pins inserted into the left and right femurs are held by the holding portions, and the distance between the left and right holding portions is held by the connecting member, the pelvis located between the left and right femurs The load applied to can be reduced. In addition, the structure in which the pin is inserted into the femur inside the body and the other holding parts and arms are installed outside the body provides sufficient initial fixation even with a thin femur. The part is small and minimally invasive.

  Further, according to the configuration of the second aspect, the femur can be bent and extended in the attached state.

  Moreover, according to the structure of Claim 3, a pin position etc. can be adjusted according to the body shape of the animal to be used.

    Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention. In each embodiment, an unprecedented animal external fixation device is obtained by adopting a novel animal external fixation device different from the conventional one, and the animal external fixation device will be described.

  First, before producing the fixing device, as a preliminary experiment, a six-degree-of-freedom electric goniometer (goniometer) was attached to a fresh dog rod, and the range of motion of the healthy hind legs was measured.

  As a result, a movable range of about 133 deg on the left and right average was obtained from the solid A (poodle: body weight 5.26 kg) and about 169 deg on the left and right average from the solid B (Maltes: weight 1.19 kg). Based on this result and the opinions of veterinarians, the goal was set so that the range of motion after inserting the fixation device was 90deg or more.

  The design is based on the premise of stabilizing the pelvis at the stage of treatment, with emphasis on biomechanical viewpoints such as securing the range of motion of the rear legs, and taking into account miniaturization to reduce biocompatibility and burden. It was.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show a first embodiment of the present invention. As shown in FIG. 1, the external fixation device 1 includes a pair of left and right U-shaped wires 2, 2. A pin 3 to be inserted into 101, a held portion 4 provided substantially parallel to the pin 3, and a connecting portion 5 for connecting the pin 3 and the held portion 4 are integrally provided. 3. In this example, the pin 3 and the connecting portion 5 form an angle of approximately 90 degrees, and the connecting portion 5 and the held portion 4 form an angle of approximately 90 degrees. In other words, the U-shaped wire 2 having the pin 3, the connecting portion 5, and the held portion 4 integrally formed by bending the wire into a substantially U-shape is obtained.

  The left and right pins 3 and 3 are held by left and right holding portions 11 and 11. The holding portion 11 includes a holding portion main body 12, a rotating shaft 14 rotatably provided by a bearing 13 provided on the holding portion main body 12, and a direction substantially orthogonal to the rotating shaft 14 from the holding portion main body 12. And a protruding connecting shaft 15. The connecting shaft 15 has a circular cross section. The left and right holding portions 11, 11 are used with the left and right rotating shafts 14, 14 facing each other. As the bearing 13, a self-aligning ball bearing is used.

  A mounting hole 16 for mounting the held portion 4 of the U-shaped wire 2 is formed in the rotating shaft 14, and the mounting hole 16 is formed so as to penetrate in a direction orthogonal to the axis of the rotating shaft 14. The held portion 4 can be fixed to the mounting hole 16 by a fixing means (not shown) in a state where the held portion 4 is inserted and positioned in the mounting hole 16.

  The left and right holding parts 11, 11 are connected by an arm 21 that is a connecting member, and the arm 21 has a circular cross section and has a curved shape so as to wrap the pelvis from the back of the animal. The arm 21 and the holding part 11 are connected by a connecting tool 22. The coupling tool 22 includes a first clamping block 23 capable of clamping and fixing the coupling shaft 15 and a second clamping block 24 capable of clamping and fixing the arm 21. The first clamping block 23 is provided with a notch-shaped clamping groove 23A, the connecting shaft 15 can slide in the length direction of the clamping groove 23A, and is clamped by operating a fastener 25 such as a bolt. The connecting shaft 15 can be fixed to the first clamping block 23 by tightening the groove 23A. The second clamping block 24 includes a notch-shaped clamping groove 24A. The arm 21 can slide in the length direction of the clamping groove 24A. The clamping tool 24 is operated to operate the clamping groove 24A. By tightening, the arm 21 can be fixed to the second clamping block 24.

  The fastener 25 is inserted into the first and second clamping blocks 23 and 24, and the angle between the first and second clamping blocks 23 and 24 is adjusted around the fastener 25 before the clamping. Thereby, the orientation of the connecting shaft 15 with respect to the arm 21 can be adjusted.

  Next, a method for using the external fixation device 1 will be described. The positions of the left and right pins 3 and 3 are adjusted according to the size of the animal, and the pins 3 and 3 are driven into the left and right femurs 101 and 101 sandwiching the pelvis 102 from the back side as shown in FIG. In the figure, reference numeral 103 denotes a hip joint composed of a femoral head and an acetabulum.

  In order to prevent the pin 3 from being dropped or loosened during mounting, the tip of the pin 3 is threaded, and the tip is inserted to the vicinity of the knee joint at the distal end of the femur 101. As a result, the bone tissue bites into the groove at the tip of the pin, and the pin 3 and the femur 101 are sufficiently fixed. The proximal end side of the pin 3 is located outside the skin, and is arranged so that the rotation shaft 14 is on the extension of the rotation center of the hip joint 103 as shown in FIG.

  The external fixation device 1 is shaped to wrap the pelvis from the back, and the left and right hip joints 103, The interval of 103 can be kept constant, and the load on the pelvis 102 in between can be reduced. Further, the hip joints 103 and 103 can be bent and extended by the bearings 13 and 13 installed on the extension of the rotation shafts of the left and right hip joints 103 and 103.

Experimental Example As shown in FIG. 2, the external fixation device 1 was attached to the dog's cadaver 111, and then the range of motion of the leg 112 was measured. The measurement was performed by reading from a 6 degree-of-freedom electric goniometer and a still image. The results are shown in Table 1. In experiments conducted on solids A and B, it was confirmed that a movable range of 100 deg or more could be secured.

また、使用したコ字形ワイヤ２の力学強度を評価するため、圧縮試験及び引張試験を行った。コ字形ワイヤ２は、直径２．０ｍｍのｋワイヤ（瑞穂医科工業株式会社製）を用い、連結部５の長さを２０ｍｍとした。そして、図４に示すような静的材料試験機（ＥＺＧｒａｐｈ：島津製作所株式会社製）を用いた。この試験機は、上下のアタッチメント121，122を備え、アタッチメント121，122の移動により被測定物の圧縮と引張とを行い、その値を測定するものあり、それら上下のアタッチメント121，122に、ピン３と被保持部４と固定し、アタッチメント121，122から側方に突出したピン３と被保持部４の突出寸法Ｓが、３ｍｍと５ｍｍの場合とで実験を行った。この突出寸法Ｓは、ピン３を実際に取り付けたときの値を参考とした。

Moreover, in order to evaluate the mechanical strength of the used U-shaped wire 2, the compression test and the tension test were done. The U-shaped wire 2 was a k-wire (made by Mizuho Medical Co., Ltd.) having a diameter of 2.0 mm, and the length of the connecting portion 5 was 20 mm. Then, a static material testing machine (EZGraph: manufactured by Shimadzu Corporation) as shown in FIG. 4 was used. This testing machine is equipped with upper and lower attachments 121, 122, and the object to be measured is compressed and tensioned by moving the attachments 121, 122, and the value is measured. 3 and the held portion 4 were fixed, and the experiment was performed in the case where the projecting dimension S of the pin 3 and the held portion 4 protruding sideways from the attachments 121 and 122 was 3 mm and 5 mm. The projecting dimension S was referred to the value when the pin 3 was actually attached.

  The test results are shown in Table 2 below.

図４の状態で、コ字形ワイヤ２に、51.6Ｎ（5.26kgf）が加わった際に、ワイヤ２で発生する変位は、最大で1.1ｍｍ程度であり、11.7Ｎ（1.19kgf）が加わった際に、ワイヤ２で発生する変位は、最大で0.4ｍｍ程度であるという結果を得た。

In the state of FIG. 4, when 51.6N (5.26kgf) is added to the U-shaped wire 2, the displacement generated in the wire 2 is about 1.1mm at the maximum, and when 11.7N (1.19kgf) is added. In addition, the maximum displacement of the wire 2 was about 0.4 mm.

  In the design of the external fixation device 1 as described above, emphasis is placed on the biomechanical viewpoint, emphasis is placed on securing mechanical strength and range of motion, and the pelvis 102 during treatment such as fracture is stabilized while external The bearings 13 installed on the left and right sides of the fixing device 1 enable flexion and extension of the hip joints 103 and 103 of the patient being treated.

  From the experimental results, it was confirmed that any of the solids measured had a bending and extension range of motion of 100 deg or more, which is sufficient for the patient to walk. And enabling walking is directly connected to reducing the stress of the patient being treated, and a positive effect on the treatment can be expected. In addition, as a structural advantage of the external fixation device 1, the pin 3 is very thin and penetrates into the body. The diameter of the pin 3 is, for example, 2.5 mm or less, and the surgical wound is extremely small. This is a point different from general surgery, and can be a great merit for patients.

  Further, from the test result of the mechanical strength of the U-shaped wire 2 used, the displacement due to the load appeared greatly immediately after the load began to be applied, and thereafter the inclination became substantially constant (111.1 N / mm). From this, it can be expected that the displacement with respect to the load can be reduced by strengthening the fixing of the connecting portion between the holding portion 11 and the U-shaped wire 2. In addition, in the experimental results related to Table 2, the load of 51.6 N is classified as the largest among the targets assumed by the external fixation device 1, and in addition, the total weight of the patient is U-shaped on one side. It is difficult to consider joining the wire 2 and it is easy to change the material of the U-shaped wire 2 to a stronger metal or the like. Therefore, it is possible to have sufficient strength for clinical application by examining the design optimization of the external fixation device 1 and the materials of each part.

  As described above, the method for fixing a fractured pelvis with the present external fixation device 1 is an effective treatment method for a pelvic fracture of a small animal that has been difficult to treat until now, and is excellent as an external fixation device for a pelvic fracture of a small animal. It is possible to stabilize the pelvis while securing the range of motion of the hind legs of the animal having a broken pelvis.

  Thus, in this embodiment, the left and right pins 3 and 3 inserted into the left and right femurs 101 and 101, the left and right holding portions 11 and 11 holding the left and right pins 3 and 3, respectively, Since the arm 21 is a connecting member that connects the holding portions 11 and 11, the pins 3 and 3 inserted into the left and right femurs 101 and 101 are held by the holding portions 11 and 11, and the left and right holding portions 11 and 11 Since the distance is maintained by the arm 21, the load applied to the pelvis 102 located between the left and right femurs 101 can be reduced. In addition, the structure in which the pins 3 and 3 are inserted into the femur 101 in the body and the other holding part 11 and the arm 21 are installed outside the body, the incision part is small and minimally invasive at the time of treatment and device detachment surgery after healing. Even with the thin femur 101, sufficient initial fixation can be obtained.

  Further, in this embodiment, since the pin 3 is rotatably held by the holding part 11, the femur 101 can be bent and extended in the attached state.

  As described above, in this embodiment, the holding portion 11 is connected to the arm 21 serving as a connecting member so that the position of the holding portion 11 can be adjusted.

  Further, as an effect of the embodiment, the pin 3 and the held portion 4 having the connecting portion 5 that is a wire in the crossing direction with the pin 3 are integrally provided, and the held portion 4 is held by the holding portion 11. The tip 3 of the pin 3 is positioned inside the body, the other part is positioned outside the body, and the held portion 4 is rotatably held, so that the femur 101 into which the pin 3 is inserted can be flexed and extended freely. It can be carried out.

  FIG. 5 shows a second embodiment of the present invention, in which the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In this example, a spherical portion 14A is provided at the base end of the rotating shaft 14, and the spherical portion 14A is supported by a bearing 13A having a receiving portion of this portion, whereby the rotating shaft 14 rotates and rotates around the axis. It is provided so as to be able to swing, and the pin 3 can move following the movement of the femur 101.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible. For example, in the embodiments, the U-shaped wire is shown, but the wire may be U-shaped or L-shaped consisting of a pin and a connecting portion. In the case of an L-shaped wire, the connecting portion is held by the holding portion. That's fine. Moreover, although aluminum alloy was mainly used for parts other than the U-shaped wire of the apparatus, the material of each member of the apparatus can be appropriately selected. Furthermore, it is only necessary that one of the left and right holding portions is connected to the arm so that the position can be adjusted.

It is a perspective view which shows Example 1 of this invention. It is explanatory drawing which shows the insertion state of the pin to a femur same as the above. It is a perspective view which shows a use condition same as the above. It is a front view of the principal part of a U-shaped wire testing apparatus same as the above. It is explanatory drawing which shows the insertion state of the pin to the femur in Example 2 of this invention.

Explanation of symbols

1 External fixation device 3 Pin 4 Held part 5 Connection part
11 Holding part
21 arm
101 femur
102 Pelvis
103 hip joint

Claims (3)

Animal external fixation device comprising left and right pins respectively inserted into left and right femurs, left and right holding parts for holding the left and right pins, and a connecting member for connecting the left and right holding parts . 2. The animal external fixation device according to claim 1, wherein the pin is rotatably held by the holding portion. The animal external fixation device according to claim 1 or 2, wherein the holding portion is connected to the connecting member so as to be adjustable in position.

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