JPH06125918A - Bone setting screw - Google Patents

Abstract

PURPOSE:To provide a bone setting screw with which a fracture can firmly be set even with the bones of a fragile part. CONSTITUTION:A bone setting screw is provided with a long, narrow screw cylinder 1 made from a highly biocompatible material with at least a portion of the outer periphery thereof externally threaded 2 and a slit 4 formed axially from an end thereof, and screw cylinder diameter enlargement means 11, 16 made from a highly biocompatible material, disposed inside the screw cylinder 1 for enlarging the screw cylinder 1 radially at the slitted portion 4 by engaging a tool with a tool engagement portion 14 formed at the end of the screw cylinder 1 and by rotating it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bone splicing screw tool used for splicing a fractured bone.

[0002]

2. Description of the Related Art Conventionally, as this type of bone joint screw tool, a simple bolt-shaped screw tool has been used.

[0003]

When joining a fractured portion with a bone-jointing screw tool, it is an essential requirement that the male screw formed on the outer periphery be firmly engaged with the bone.

However, among the bones, for example, the cancellous bone portion and the femoral head of the thigh, etc., the bone itself is fragile. Therefore, when the bone splicing screw tool is tightened a little, it becomes a so-called screw stupid, and the screw is a bone. It is not possible to firmly join the broken bones without engaging with. On the other hand, if you don't tighten the screws properly, you won't be able to join the broken bones together.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a bone-jointing screw tool capable of firmly and firmly joining a fractured portion even if it is a fragile bone.

[0006]

In order to achieve the above-mentioned object, the bone-jointing screw tool of the present invention has a male screw formed on at least a part of its outer periphery and an axial slot formed from the distal end side. And a slender tubular screw cylinder made of a material having high biocompatibility, and a tool engaging portion formed on the proximal end side formed of a material having high biocompatibility and arranged in the screw cylinder. And a screw cylinder diameter enlarging means for expanding the screw cylinder in the radial direction at the portion where the slot is formed by engaging and rotating the screw cylinder.

The means for enlarging the diameter of the screw cylinder includes a screw rod inserted into the screw cylinder from the base end side of the screw cylinder,
The screw cylinder may be formed with a diameter enlarging member which is engaged with the screw rod at the tip of the screw cylinder and is rotated in the screw rod to be pulled inward in the screw cylinder to expand the diameter of the screw cylinder. Or alternatively, the screw cylinder diameter enlarging means is formed on the base end side of the screw rod by forming a screw rod inserted into the screw barrel from the tip end side of the screw barrel and a tool engaging portion. From a nut that is screwed to the male screw and a diameter expansion member that is integrally formed at the tip of the screw rod and that is pulled toward the inside of the screw cylinder by rotating the nut to expand the diameter of the screw cylinder. It may be

Along the axial direction, slits are formed on both the tip end side and the base end side of the threaded cylinder, and male threads are formed on both the tip side outer circumference and the base end side outer circumference of the threaded cylinder.
The screw cylinder diameter enlarging means may expand the diameter of the screw cylinder on both the front end side and the base end side.

[0009]

After the screw cylinder is screwed into the bone so as to join the fractured bones together, the tool is engaged with the tool engaging portion formed at the base end of the screw cylinder diameter enlarging means to open the screw cylinder diameter enlarging means. When rotated, the threaded cylinder is expanded in the radial direction at the part where the slot is formed, the male threaded part formed on the outer periphery of the threaded cylinder firmly engages the bone, and the fractured bones are firmly joined together. .

[0010]

Embodiments will be described with reference to the drawings. 1 and 2 show a first embodiment of the present invention.

In FIG. 2, reference numeral 1 denotes a screw cylinder having a male screw 2 formed on the outer periphery of a half portion near the tip. However, the male screw 2 may be formed in a range according to the purpose of use, and may be formed over the entire length of the outer circumference of the screw cylinder 1 or may be formed at a very small part of the tip.

The outer circumference of the male screw 2 portion is formed with a slightly tapered outer diameter so that it can be easily screwed into a tap hole or the like formed in a bone or the like. The screw cylinder 1 is formed of a material having high biocompatibility, for example, titanium, stainless steel, cobalt, or the like into an elongated cylinder shape as a whole, and a through hole 3 is formed at the central axis position over the entire length.

Between the tip end side of the screw cylinder 1 and the vicinity of the base end part, slits 4 are formed in a cross shape at intervals of 90 degrees in the axial direction. A tapered portion 6 having a divergent tip is formed at the tip of the through hole 3.

The head 7 on the base end side of the screw cylinder 1 is formed to have a large outer diameter, and the lower surface side thereof is rounded to a spherical shape so as not to damage the bone or the like with which it abuts. Further, the head 7 is formed with, for example, a hexagonal hole-shaped tool engaging portion 8, and a counterbore hole 9 is formed at the base end side mouth of the through hole 3 immediately behind it.

Reference numeral 11 designates the screw cylinder 1 in the through hole 3 of the screw cylinder 1.
Is a threaded rod that is inserted from the base end side, and a male screw 12 is formed at the tip end portion thereof. Head 1 of screw rod 11
3 is formed thick enough to fit inside the counterbore hole 9 of the screw cylinder 1, and there, for example, a hexagonal hole-shaped tool engaging portion 1
4 are formed.

A guide hole 15 for inserting a guide thread or the like is formed at the central axis position of the screw rod 11 so as to penetrate therethrough over its entire length. It should be noted that similar guide holes are formed in the second and subsequent embodiments described later, but the illustration thereof is omitted.

Reference numeral 16 denotes a male screw 1 at the tip of the screw rod 11.
It is a spherical body (diameter enlarging member) formed with a female screw 17 that is screwed into the screw cylinder 2, and is formed in a size that comes into contact with the inner surface of the tapered portion 6 at the tip of the screw cylinder 1. The spherical body 16 and the screw rod 11 are also made of a material having a high biocompatibility.

FIG. 1 shows the use state of the above embodiment, in which the bone fragments 81 on the back side of the bone fragments 81, 82 separated by fracture.
Is pre-tapped by tapping the male screw 2 on the outer circumference of the screw cylinder 1
A female screw 83 that engages with is formed, and a hole 84 through which the male screw 2 portion of the screw cylinder 1 passes is formed in the front bone piece 82.

In the threaded cylinder 1, a threaded rod 11 is passed through the through hole 3 and a spherical body 16 is lightly screwed into a male screw 12 at the tip of the threaded rod 11. Then, in that state, the screw cylinder 1 is inserted into the bone pieces 81 and 82, the tool is engaged with the tool engaging portion 8 of the screw cylinder 1 to rotate the screw cylinder 1, and as shown in FIG. The male screw 2 is screwed into the female screw 83 of the bone piece 81.

When the head 7 of the screw cylinder 1 is in a state of pressing the front bone piece 82 against the back bone piece 81, the screw rod 11
A tool is formed on the tool engaging portion 14 of the head 13 and the screw rod 11 is rotated.

Then, the spherical body 16 is pulled inward from the tip end side of the screw cylinder 1 toward the inside of the screw cylinder 1, whereby the screw cylinder 1 is radially expanded at the portion where the slot 4 is formed.

As a result, the male screw 2 portion on the outer circumference of the screw cylinder 1 firmly bites into the surrounding bone piece 81 and is firmly engaged. Therefore, even if the bone pieces 81 and 82 are fragile portions, the bones 81 and 82 can be firmly fixed without loosening.

In order to prevent the spherical body 16 from rotating together with the screw rod 11 when it is rotated, the spherical body 16 and the tapered portion 6 at the tip of the screw cylinder 1 are relatively fixed. It is advisable to form a rotation stopper to prevent such rotation.

FIG. 3 shows a second embodiment of the present invention, in which a threaded rod 21 is formed with a male screw 22 on its base end side, and a tool engaging portion formed of, for example, a driver groove is formed therein. Two
4 is formed by screwing the nut 27 into the diameter enlarging member 26.
Is integrally formed at the tip of the screw rod 21.

Even if formed in this manner, by engaging the tool with the tool engaging portion 24 of the nut 27 and rotating the nut 27, the diameter enlarging member 26 is moved from the tip end side of the screw cylinder 1 to the inside of the screw cylinder 1. The diameter of the screw cylinder 1 is expanded by being pulled in the direction, and functions in the same manner as in the first embodiment.

In this embodiment as well, the structure of the screw cylinder 1 is the same as that of the first embodiment, but in the first embodiment, the screw rod 11 is inserted from the base end side of the screw cylinder 1 into the screw cylinder 1. In contrast, the threaded rod 21 of the second embodiment is inserted from the tip side of the screw cylinder 1.

FIG. 4 shows a third embodiment of the present invention in which the head portion 7 is removed from the screw cylinder 1. 37
Is a key for stopping rotation. Although the screw rod 11 has the same structure as that of the first embodiment, it may be the same as that of the second embodiment.

The bone joint screw device of the third embodiment thus constructed is fixed to the fractured femoral head 91 in the same manner as in the above-mentioned respective embodiments, as shown in FIG. 5, for example. After that, a so-called tube plate 38 is engaged with the base side, and the plate portion 38a of the tube plate 38 is screwed to the bone. 38b is a groove into which the rotation stopping key 37 is fitted.

The space is filled with cement and firmly fixed. Further, as the screw 39 for screwing, the bone fastener screw having the structure of the above-described first or second embodiment may be used.

FIG. 6 shows a fourth embodiment of the present invention in which male screws 52 are formed on both the outer circumferences of the tip end side and the base end side of a screw cylinder 51, and both the tip side and the base end side are formed. A slit 54 is formed in the axial direction up to the vicinity of the central portion.

The tapered portion 56 is also formed on both the tip end side and the base end side, the screw rod 21 has the same structure as that of the second embodiment, and the inner surface side of the nut 27 has a diameter expanding function. It has a spherical shape so as to have. as a result,
After inserting the screw rod 27 into the through hole 53 in the screw cylinder 51,
By tightening the nut 27, the diameter of the screw cylinder 51 is expanded on both the front end side and the base end side.

The present invention is not limited to the above-described embodiment. For example, the diameter enlarging member does not necessarily have to be spherical, and the diameter of the screw cylinder can be expanded by being drawn into the screw cylinder. Any shape may be used as long as it is.

[0033]

According to the bone-jointing screw tool of the present invention, the diameter of the screw cylinder screwed into the bone can be expanded and the male screw portion formed on the outer periphery thereof can be firmly engaged with the bone. Therefore, even if the bone is a brittle portion, it has an excellent effect that the fractured part can be firmly and reliably spliced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a usage state of a first embodiment.

FIG. 2 is a vertical cross-sectional view of an exploded state of the first embodiment.

FIG. 3 is a vertical sectional view of a second embodiment in an exploded state.

FIG. 4 is a vertical sectional view of a third embodiment in an exploded state.

FIG. 5 is a cross-sectional view of a third embodiment in use.

FIG. 6 is a vertical sectional view of a disassembled state of a fourth embodiment.

[Explanation of symbols]

 1 screw cylinder 2 male screw 3 slot 11 screw rod 14 tool engaging part 16 spherical body (diameter expanding member)

Claims (4)

[Claims] 1. A slender tubular screw cylinder made of a material having high biocompatibility in which a male screw is formed on at least a part of the outer circumference and a slit is formed in the axial direction from the distal end side, and high biocompatibility. The screw cylinder is made of a material and is disposed in the screw cylinder, and a tool is engaged with a tool engagement portion formed on the base end side to rotate the screw cylinder at a portion where the slot is formed. And a screw tube diameter enlarging means for pushing and expanding in a direction. 2. The threaded rod diameter enlarging means includes a threaded rod inserted into the threaded barrel from the base end side of the threaded barrel, and the threaded rod screwed at the tip of the threaded barrel with the threaded rod. The screw tool for bone joints according to claim 1, further comprising a diameter enlarging member that pushes the diameter of the screw cylinder by expanding the diameter of the screw cylinder by rotating the screw cylinder. 3. The screw cylinder diameter enlarging means is formed on the base end side of the screw rod by forming a screw rod inserted into the screw barrel from the front end side of the screw barrel and a tool engaging portion. A nut that is screwed into the male screw, and a diameter expansion member that is integrally formed at the tip of the threaded rod and that is pulled toward the inside of the screw cylinder by rotating the nut to expand the diameter of the screw cylinder. The bone fastener screw tool according to claim 1, which comprises 4. A threaded groove is formed in the threaded cylinder in the axial direction from both the tip side and the base end side, and male threads are formed in both the outer circumference on the tip side and the base end side of the threaded cylinder. The screw tool for bone splicing according to claim 1, 2 or 3, wherein the screw cylinder diameter enlarging means expands the diameter of the screw cylinder on both the distal end side and the proximal end side.