JP2805464B2 - V-shaped intramedullary nail with bottom hole - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-shaped intramedullary nail having a bottom hole for use in treating a fracture of a long bone, which is a bone of a limb of a human or an animal. When the intramedullary nail is fixed to the cortical bone, the position of the fixing through-hole of the intramedullary nail can be easily recognized without need of fluoroscopy.

[0002]

2. Description of the Related Art When an intramedullary nail is inserted into a medullary cavity of a broken long bone and is boned, if the stumps of the fracture part are rotated left and right separately and twisted, fusion of the fracture ends is hindered. . Therefore,
In order to prevent the rotation of the fracture end, it is necessary to fix the intramedullary nail to the cortical bone by hitting a fixing pin, tying it with a wire, or screwing it to two places on both sides of the fracture. Therefore, two pairs of fixing through-holes are provided at the front and rear ends of the nail wall of the intramedullary nail having an annular or rectangular cross section, which penetrate the nail wall at right angles. This through hole is generally called a lateral hole, and a pair of through holes must be drilled in the cortical bone in order to pass a wire or a screw through the pair of lateral holes. However, when the intramedullary nail is inserted into the medullary cavity, the lateral hole is hidden inside the cortical bone, so that it cannot be seen. Therefore, while seeing through X-rays, we searched for a position where a pair of side holes on the front and back overlap and could be seen through in a perfect circle,
The drill had to be carefully pushed into the window. Such a drilling operation is extremely troublesome, requires a great deal of skill, and if the operation time is prolonged, it may adversely affect radiation exposure to doctors, assistants, and patients.

In order to solve the above-mentioned drawback of X-ray fluoroscopy, Japanese Patent Application Laid-Open No. 7-21535 discloses a pipe-shaped intramedullary nail having a large number of lateral holes penetrating the entire wall surface. Inserting this porous tubular intramedullary nail into the medullary cavity and drilling it into the cortical bone using a very fine drill will hit any of the many lateral holes. Therefore, it is unnecessary to search for a lateral hole by X-ray fluoroscopy.

[0004]

However, in the above-mentioned conventional porous tubular intramedullary nail, there is no guarantee that the drilling of the cortical bone only needs to be performed once. If it does not hit the side hole well, it must be drilled many times into the cortical bone, which is very inconvenient. Moreover, the drill that has passed through the side hole must be kept pressed straight down, hitting the drill on the other side hole facing the other side, that is, on the opposite side of the tube wall, and penetrating the drill out of the cortical bone on the opposite side. No. Propelling an electric drill straight into a side hole that cannot be seen is a very difficult task. In addition, if the wall of the nail is inadvertently damaged with a drill, the strength of the nail may be significantly degraded, and the metal powder chips flying into the medullary cavity may have a negative physiological effect on the patient. There is anxiety to bring.

The present invention has been made in view of the above-mentioned drawbacks of the conventional porous tubular intramedullary nail, and has made it possible to fix the intramedullary nail extremely simply and securely without performing X-ray fluoroscopy.
It is intended to provide a new V-shaped intramedullary nail with a bottom hole.

[0006]

In order to achieve the above object, the present invention provides an intramedullary nail body having a V-shaped trough-like cross-section, and extending in the longitudinal direction of the valley bottom of the intramedullary nail body. A plurality of bottom holes are formed at regular intervals.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS By taking the above solution, a plurality of bottom holes drilled at equal intervals function as "scales of a ruler", and a V-shaped inclined surface serves as a fixing pin for fixing. Acts as a "guide" for guiding to the bottom hole.

That is, the V-type intramedullary nail with a bottom hole of the present invention is inserted into the medullary cavity from the head of the bone as shown in FIG. The fixing pins 7, 7 'for fixing are driven inward. Therefore,
The rear part of the intramedullary nail body 1 inserted into the medullary cavity is exposed from the head of the bone. Therefore, open both legs of the split compass such as a divider in accordance with the drilling interval of the bottom holes 2... With the bottom hole 2 a at the back of the intramedullary nail exposed from the head of the bone as the base point, rotate the compass halfway forward. Move. By doing this,
As if pointing to the scale of the ruler, the position of the bottom hole 2 hidden under the cortical bone 8 can be accurately and easily determined. This not only eliminates the need for troublesome X-ray fluoroscopy, but also completely eliminates the anxiety that a conventional perforated tubular intramedullary nail does not hit or side off with a single shot.

When the position of the bottom hole 2... Under the cortical bone is determined, the compass is placed on the cortical bone 8 on the ceiling with the intramedullary nail body 1 in a trough-like shape, that is, with the valley bottom facing downward. To apply. Then, after making a mark on the cortical bone at the leg end of the compass, a fixing pin 7 for fixing a round pile is hammered into the mark with a hammer. Then, as shown in FIG. 5A, since the bottom hole 2 is opened immediately below the mark with the bone marrow cavity 9 therebetween, the pin 7 can be passed through the bottom hole 2 without difficulty if the pin 7 is driven straight. Even if the pin 7 is tilted slightly obliquely during driving, the pin 7 can be received by the V-shaped slopes 4 and 4 '.
By the guide action of the slope, the tip of the pin 7 is guided to the bottom hole 2 while sliding along the slope. Therefore, the stop pin 7 can be passed through the bottom hole 2 with absolute certainty and ease when the tapping is continued. After passing through the bottom hole 2, FIG.
As shown in B, the intramedullary nail can be extremely easily fixed to the cortical bone by further tapping the buttocks of the pin 7 and penetrating the cortical bone 8 on the opposite side. Since the locking pin can be directly driven into the cortical bone in this way, the trouble of previously drilling the cortical bone with a drill such as a conventional porous tubular intramedullary nail becomes unnecessary. For this reason, the operation time is significantly reduced.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the drawings are for explanation only, and do not limit the scope of the present invention.

FIGS. 1 and 2 are a perspective view and a plan view, respectively, showing an embodiment of a V-shaped intramedullary nail with a bottom hole according to the present invention. . Reference numeral 1 denotes an intramedullary nail body, which is shaped like a trough having a V-shaped cross section. 2
Is a circular bottom hole, which is drilled at regular intervals in the longitudinal direction of the valley bottom 3 of the intramedullary nail body 1 at a constant distance. The shape and size of the bottom hole 2 and the number and spacing of the holes are optional. The valley bottom 3 corresponds to a vertex of a triangle having the pair of slopes 4 and 4 'as isosceles, and an inner angle of about 50 degrees is optimal. Interior angle is 30
A range of -90 degrees is preferable, but not particularly limited. The tip of the intramedullary nail main body 1 may be cut obliquely and pointed like a point.

In the above embodiment, the edges 5, 5 'of the slopes 4, 4' and the ridge line 6 at the bottom of the valley are formed at an acute angle. The purpose is to prevent the rotation of the inner nail. That is, the purpose is to prevent the rotation of the intramedullary nail in the bone marrow by hooking the edge to the cancellous bone in the bone head instead of the fin. To form the ridge line 6 at an acute angle, FIG.
As shown in A, using two strip-shaped metal pieces having a trapezoidal cross section,
What is necessary is just to weld one long side of each material.

However, since the welding step increases the manufacturing cost, it is not always necessary to form the edges 5, 5 'and the ridge line 6 at an acute angle. For example, as another embodiment, as shown in FIG. 3, an elongated strip-shaped metal plate is folded in half at the median line in the longitudinal direction to obtain an intramedullary nail body 1a, and the fold portion, that is, the ridge line 6a is a round blunt edge. Even if left as it is, the effect of the present invention is sufficiently exhibited. Depending on the bending method, the cross section may be U-shaped, but a round gutter-shaped intramedullary nail having a substantially U-shaped cross section is also included in the scope of the present invention, as long as the guiding action of the slope is not impaired. In short, it is only required that the inside of the tubular cortical bone 8 can be reliably supported by the three convex portions of the edges 5, 5 'and the ridge line 6. The metal plate used to manufacture the V-type intramedullary nail is optimally made of titanium alloy.
The material is not particularly limited.

[0014] The practicality of the present invention was tested using an experimental animal cat (male, 4 years old, weighing 4.2 kg). The intramedullary nail body 1 prototyped to fit the femur of a cat has a length of 15c.
m, width 8 mm, thickness 1 mm, bend the belt-like titanium plate in the length direction, and 1.6 m in diameter at the valley bottom 3 5 mm forward from the nail tail.
m, and a circular bottom hole 2a is formed.
A total of six bottom holes 2 are provided at m intervals.

At the time of the experiment, first, the fracture 1
After exposing 0, the diameter is 4 mm from the fracture end to the head.
A Kirschner steel wire was driven in to form a guide groove penetrating the head. If guide grooves are formed in advance,
The intramedullary nail body 1 can be easily inserted into the medullary cavity from the head of the bone without having to form the tip of the intramedullary nail body 1 into a pointed shape. After the intramedullary nail body 1 is inserted, as shown in FIG. 4, the fractures 10 are inserted so that the fracture ends come into close contact with each other.
To reduce. Next, both leg ends of the compass are opened to a width of 20.8 mm, and the positions of the bottom holes 2... Hidden below the cortical bone are determined based on the bottom holes 2a exposed from the head of the bone. Then, with the fracture 10 as the center, the left and right sides 2
A mark is placed on the cortical bone 8 at the location, and a round rod-shaped stainless steel stop pin 7 having a diameter of 1.5 mm and a length of 5 cm is hammered into one of the marks with a hammer. The locking pin 7 has a diameter of 1.
It passes through a 6 mm bottom hole 2 and penetrates the cortical bone 8 on the opposite side of the implantation site. Similarly, as shown in FIG. 4, another stop pin 7 'may be driven into one of the marks. Finally, if the both ends of the two pins 7 and 7 ′ protruding outside the cortical bone 8 are appropriately cut off and the operation field is sutured, the osteotomy can be completed in a very short time.

As a result of the above experiment, the technique of the present invention in which the pin is directly driven into the cortical bone is different from the conventional technique, that is, the method of drilling the cortical bone with a drill for passing a wire or screw for fixing an intramedullary nail. It was confirmed that the operation time was extremely short. That is, in the conventional screwing that relies on X-ray fluoroscopy, it often took more than one hour to attach one screw. No matter how skilled a doctor, it takes at least 30 minutes. However, if the V-type intramedullary nail of the present invention is used, the driving of two pins can be completed in about 5 minutes after insertion into the bone marrow. Therefore, neither the doctor nor the patient gets tired. Of course, there is no fear of radiation exposure. Moreover, in 8 cats and 5 dogs that were subjected to fracture treatment experiments, all of the cases showed a successful fusion of the fractured part. In other words, it was proved that the fixing performance of the V-shaped intramedullary nail with the bottom hole by the driving of the pin was perfect, and that the rotation of the fractured portion was never caused.

As is apparent from the above description, when the V-shaped intramedullary nail with a bottom hole according to the present invention is used, a plurality of bottom holes drilled at equal intervals serve as scales of a ruler. The location of the bottom hole hidden beneath the can be accurately determined without having to see through an X-ray. Further, since the pair of slopes inclined in a V-shape function as guides, even if the stopper pin driven into the cortical bone is slightly inclined, it can be reliably guided to the bottom hole. For this reason, it is not necessary to drill the cortical bone in advance with a drill to prevent the inclination of the pin, and the pin can be directly driven into the cortical bone. Therefore, there is a remarkable effect that the anxiety of X-ray exposure is completely eliminated and the operation time is significantly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a V-shaped intramedullary nail with a bottom hole according to the present invention.

FIG. 2 is a plan view of the above.

FIG. 3 is a sectional view showing another embodiment of a V-shaped intramedullary nail with a bottom hole according to the present invention.

FIG. 4 is a side view showing a usage state of a V-shaped intramedullary nail with a bottom hole according to the present invention.

FIG. 5 is a schematic cross-sectional view illustrating the operation of the V-shaped intramedullary nail having a bottom hole according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Intramedullary nail main body 2, 2a Bottom hole 3 Valley bottom 4, 4 'Slope 5, 5' edge 6, 6a Ridge 7, 7 'Stop pin 8 Cortical bone 9 Marrow cavity 10 Fracture part

Claims (1)

(57) [Claims] An intramedullary nail body is formed in a trough shape having a V-shaped cross section, and a plurality of bottom holes are formed at equal intervals in a length direction of a valley bottom of the intramedullary nail body. V-type intramedullary nail with a bottom hole.