JP2023044382A - surgical guide pin - Google Patents

Abstract

To provide a guide pin capable of suppressing effectively a corotation phenomenon with a hollow drill or the like.SOLUTION: A surgical guide pin is a guide pin used for bone perforation, and is characterized in that (1) a guide pin has a tip part on the tip side oriented to a traveling direction, and a shaft part connected to the tip part, (2) a cutting part is formed on the terminal of the tip part, and (3) a cross-sectional diameter of the tip part is smaller than a cross-sectional diameter of the shaft part.SELECTED DRAWING: Figure 1

Description

The present invention relates to novel surgical guide pins. In particular, the present invention relates to a guide pin used for introducing a hollow drill or the like into bone.

BACKGROUND ART When surgically treating an injury such as a fracture of a femur or the like, it is necessary to immobilize the fracture site. The method of fixing the fracture site is roughly divided into external fixation, which is fixed from the outside of the body, and internal fixation, which is fixed inside the body. If sufficient fixation force cannot be obtained, internal fixation is used.

Internal fixation is performed by surgically placing a fixing member such as a rod, wire, screw, plate, or pin in the body.

For example, in a femoral neck fracture, as shown in FIG. 2, in the femur 21, a guide pin 22 is inserted toward the femoral head 21a so as to straddle the neck fracture site 23 at a substantially right angle. Next, using a hollow drill 25, a guide pin 22 was inserted into the hollow portion 25a of the hollow drill 25, and the guide pin 22 was advanced along the guide pin 22 electrically or manually to form a lumen, after which the guide pin 22 was placed in the lumen. Only the hollow drill 25 is removed in this state. Temporary fixation of the neck fracture site 23 is thus performed. After that, in a state temporarily fixed by the guide pin 22, a threaded rod (not shown) called a lag screw is embedded along the guide pin 22, and the guide pin is pulled out. Next, the final fixation of the neck fracture site 23 is completed by performing a treatment such as suturing the skin. 2, a rod-shaped body called a nail is embedded in the medullary cavity of the femur along the bone axis 24, and a lag screw is inserted so as to cross the nail. However, these points are omitted in FIG.

Various products have been developed as such guide pins. For example, the central A guide pin is known in which each of the plurality of grooves is convex toward the central axis when viewed in cross section perpendicular to the axis (Patent Document 1).

Further, for example, a pin-shaped base material having a cone-shaped tip, which is composed of a base material made of a radiolucent metal and a surrounding material made of a radiopaque metal, is used as a scale along the longitudinal direction. A graduated medical guide pin has been proposed, which is characterized in that the surrounding material is attached at intervals and the surface is made flat (Patent Document 2).

JP 2018-198985 JP 2014-113203

However, when a conventional guide pin is inserted into a hollow drill and the bore is drilled, a phenomenon called "co-rotation" occurs in which the guide pin, which should not rotate originally, also rotates. The main reason for this is thought to be that the gap between the inner wall of the hollow portion (through hole) of the hollow drill and the outer circumference of the guide pin is clogged with bone chips generated during drilling (the gap bites bone chips). there is If co-rotation occurs, the guide pin may also act as a drill, drilling to an unintended depth and causing unnecessary damage to the surrounding tissue.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a guide pin capable of effectively suppressing co-rotation with a hollow drill or the like.

As a result of earnest research in view of the problems of the prior art, the inventors of the present invention have found that a guide pin having a specific structure can achieve the above objects, and have completed the present invention.

That is, the present invention relates to a surgical guide pin described below.
1. A guide pin for use in bone drilling, comprising:
(1) The guide pin has a tip portion on the tip side in the traveling direction and a shaft portion connected to the tip portion,
(2) A blade is formed at the end of the tip,
(3) the cross-sectional diameter of the tip is smaller than the cross-sectional diameter of the shaft;
A surgical guide pin characterized by:
2. 2. The surgical guide pin according to item 1, wherein the cross-sectional diameter of the tip portion is 92 to 98% of the cross-sectional diameter of the shaft portion.
3. 2. The surgical guide pin according to item 1, wherein the cross-sectional diameter of the tip portion continuously decreases toward the blade portion.
4. 4. The surgical guide pin according to any one of items 1 to 3, wherein the shaft portion has a cross-sectional diameter of 2.5 to 3.5 mm.
5. 5. The surgical guide pin according to any one of items 1 to 4, wherein the length of the tip portion is 5 to 25% of the total length of the guide pin.
6. 6. The surgical guide pin according to any one of items 1 to 5, which is non-threaded.

ADVANTAGE OF THE INVENTION According to this invention, the guide pin which can suppress effectively the co-rotation phenomenon with a hollow drill etc. can be provided. In particular, since the guide pin of the present invention is designed so that the cross-sectional diameter of the tip is smaller than the cross-sectional diameter of the shaft, the hollow drill is driven with the guide pin inserted into the hollow portion of the hollow drill. Even if this is done, the gap between the outer circumference of the guide pin and the inner wall of the hollow portion of the hollow drill becomes relatively large, so bone chips (bone powder) are less likely to clog. As a result, it becomes difficult for the guide pin in the hollow portion to synchronize with the rotation of the hollow drill, and it is possible to suppress co-rotation.

In addition, by controlling the length of the tip to a certain length, it is possible to ensure a sufficient contact area between the outer circumference of the shaft and the inner surface of the hollow. The hollow drill can be stably supported by being arranged in such a manner that the tip of the hollow drill is less likely to deviate from the center.

The guide pin of the present invention having such characteristics can be suitably used particularly for procedures requiring drilling while being inserted into the hollow portion of a hollow drill (including a hollow reamer and the like). Therefore, for example, femoral shaft fracture, femoral neck fracture, femoral trochanteric/subtrochanteric fracture, calcaneus fracture, pelvic fracture, tibia fracture, etc. It can be suitably used as a guide pin for treatment of various fractures such as fractures of the upper extremities such as proximal humeral fractures, forearm fractures, clavicle fractures, and distal radius fractures.

It is a figure which shows the outline|summary of the guide pin of this invention. FIG. 1A shows a configuration in which the tip cross-section has a constant cross-sectional diameter, and FIG. 1B shows a configuration in which the cross-sectional diameter tapers from tip to tip. 1A-1 and 1B-1 each show a state viewed from direction a. 1A-2 and 1B-2 each show the state viewed from direction b. FIG. 4 is a schematic diagram showing a state of insertion of a guide pin at the time of neck fracture of the femur. It is a figure which shows an example of the cross-sectional shape of the front-end|tip part or shaft part of the guide pin of this invention. It is a figure which shows the outline|summary of this invention guide pin used in the Example. FIG. 4-1 is a diagram showing the appearance of the entire guide pin. FIG. 4-2 is a longitudinal sectional view of the guide pin. FIG. 4-3 is a detailed view of part A of FIG. 4-1. FIG. 4-4 is a cross-sectional view taken along line BB of FIG. 4-2. FIG. 4-5 is a detailed view of part D in FIG. 4-2. FIG. 4-6 is a view of FIG. 4-2 viewed from direction C. FIG.

Reference Signs List 10, 10' surgical guide pin 11 tip portion 12 shaft portion 13 blade portion (head)
21 femur 21a (femur) head 22 guide pin 23 neck fracture site 24 femoral longitudinal direction 25 hollow drill 25a hollow part (through hole) of hollow drill

The surgical guide pin of the present invention (the guide pin of the present invention) is a guide pin used for bone drilling,
(1) The guide pin has a tip portion on the tip side in the traveling direction and a shaft portion connected to the tip portion,
(2) A blade is formed at the end of the tip,
(3) the cross-sectional diameter of the tip is smaller than the cross-sectional diameter of the shaft;
It is characterized by

FIG. 1 shows a schematic diagram of the guide pin of the present invention. The guide pin 10 of FIG. 1A has a leading end portion 11 on the leading end side in the traveling direction and a shaft portion 12 connected to the leading end portion 11 as main portions. The tip portion and the shaft portion may be configured by connecting separate parts, or both may be formed integrally. From the standpoint of strength, etc., it is desirable that the tip portion and the shaft portion are integrally molded. For example, it is possible to suitably use a guide pin that is processed so that the cross section is thinner than the shaft portion by cutting a portion corresponding to the tip portion of a rod-shaped body having a constant cross-sectional diameter.

The total length of the guide pin of the present invention varies depending on, for example, the site to be treated, the method of treatment, etc., and is not particularly limited. Therefore, it can be set within a range of about 200 to 600 mm, for example.

The cross-sectional shape of the distal end portion 11 is not limited. For example, as shown in FIG. , FIG. 3D). When the cross-sectional shape is circular (if it is not circular, the circumscribed circle) diameter (hereinafter referred to as "cross-sectional diameter") can generally be about 1.5 to 3.5 mm. Not limited.

Here, the guide pin of the present invention is characterized in that the cross-sectional diameter of the tip portion is smaller than the cross-sectional diameter of the shaft portion. For example, as shown in FIG. 1A-2, the cross-sectional diameter of the tip portion is smaller than the cross-sectional diameter of the shaft portion 12 . As a result, when the guide pin is inserted into the hollow portion (through hole) of the hollow drill, fine bone chips generated during bone drilling are caught between the outer circumference of the guide pin and the inner circumference of the hollow portion. It is possible to effectively suppress the phenomenon that the guide pin rotates in synchronism with the hollow drill.

In this case, the ratio of the cross-sectional diameter (D ₁₁ ) of the tip portion to the cross-sectional diameter (D ₁₂ ) of the shaft portion is not particularly limited, and should be within a range that can sufficiently suppress the above phenomenon (co-rotation phenomenon). For example, it can be appropriately set according to the site where the guide pin is used, the treatment method, and the like. Therefore, in the present invention, for example, 0.85 D ₁₂ ≤ D ₁₁ ≤ 0.98 D ₁₂ , preferably 0.90 D ₁₂ ≤ D ₁₁ ≤ 0.95 D ₁₂ . By setting the diameter within such a range, the distance between the outer circumference of the tip portion and the inner surface of the hollow drill can be more reliably made larger than the particle size of most bone chips (bone powder).

In addition, in the configuration of FIG. 1A, the cross-sectional diameter of the distal end portion 11 is constant over the entire length of the distal end portion, but as another embodiment, as shown in FIG. can be In this case, the cross-sectional diameter _Dmin of the thinnest portion can be set to be the same as the above conditions. That is, for example, 0.85 D ₁₂ ≤ D _min ≤ 0.98 D ₁₂ , preferably 0.90 D ₁₂ ≤ D _min ≤ 0.95 D ₁₂ .

The length of the distal end portion 11 may be set within a range that can sufficiently suppress the phenomenon described above. can be, but is not limited to. In particular, in the present invention, the ratio of the length (L ₁₁ ) of the tip portion 11 to the total length (L) of the guide pin can be, for example, 0.05L≦L ₁₁ ≦0.25L, preferably 0.07L. ≦L ₁₁ ≦0.18L. If the value of _L11 is too small, the effect of suppressing the co-rotation phenomenon may decrease. On the other hand, if the value of _L11 is too large, the tip becomes excessively long, and as a result, the gap between the outer circumference of the tip and the inner wall of the hollow becomes long. In addition, there is a risk that the center position of the hollow drill is likely to shift during the procedure. The guide pin of the present invention is desirably arranged in the center of the cross section of the hollow portion of the hollow drill (that is, it is preferably concentric). becomes.

A blade portion is formed at the distal end of the tip portion 11 . As a result, the guide pin can be efficiently inserted into the bone. The shape, size, etc. of the blade may be the same as those of known or commercially available guide pins, and are not particularly limited. Therefore, for example, it is possible to adopt either a double pointed type, a threaded type, or the like.

The distal end portion of the guide pin of the present invention may be either a threaded type or a non-threaded type, but the non-threaded type is preferable in that co-rotation can be suppressed more effectively. In the case of a threaded type, the shape and the like can be set in the same manner as known or commercially available guide pins.

The length of the shaft portion 12 is not particularly limited. As will be described later, it can be a numerical value obtained by subtracting the length of the tip portion from the total length. Therefore, it can be set within a range of about 200 to 500 mm, for example.

The end (tail) of the shaft portion 12 in the direction opposite to the tip is not particularly processed in FIG. . For example, it can be a polygon (particularly a regular polygon) (FIG. 3B), a shape obtained by cutting a circular arc (FIGS. 3C and 3D), or the like. Alternatively, the tail portion may be processed into a plate shape. Also, for example, an anti-rotation type configuration can be employed. As a result, for example, it can be attached to an inserter, an extractor, or the like with one touch. All of these can employ configurations and mechanisms employed in known guide pins.

The cross-sectional shape of the shaft portion 12 is not limited. For example, as shown in FIG. 3D), etc. When the cross-sectional shape is circular (if it is not circular, the circumscribed circle) diameter (hereinafter referred to as "cross-sectional diameter") can generally be about 1.5 to 3.5 mm. It is not limited, and can be appropriately set according to, for example, the cross-sectional diameter of the hollow portion of the hollow drill. For example, the cross-sectional diameter of the shaft portion can be about 95 to 99% of the cross-sectional diameter of the hollow portion.

The length of the shaft portion 12 is not particularly limited. As will be described later, it can be a numerical value obtained by subtracting the length of the tip portion from the total length. Therefore, it can be set within a range of about 200 to 500 mm, for example.

The material of the tip portion 11 and the shaft portion 12 is not particularly limited, and metals (including alloys) such as stainless steel (SUS304, SUS316, etc.), titanium alloys, cobalt-chromium alloys, etc. can be suitably used. can. Further, the tip portion 11 and the shaft portion 12 may be made of the same material, or may be made of different materials.

The guide pin of the present invention can be used in the same manner as known or commercially available guide pins. In particular, it can be suitably used as a guide pin for hollow drills. More specifically, a guide pin is inserted into the bone, and a lumen is formed while inserting the guide pin into the hollow portion (through hole) of the hollow drill. At this time, the hollow drill is drilled while rotating while the guide pin is inserted into the hollow portion. Since the tip of the guide pin of the present invention has a specific shape, bone chips are less likely to clog, thus co-rotation is effective. effectively prevented. After forming the lumen, treatment can be performed in the same manner as the conventional treatment method.

EXAMPLES Examples are given below to more specifically describe the features of the present invention. However, the scope of the present invention is not limited to the examples.

[Example 1]
A guide pin as shown in FIG. 4 was produced. A predetermined guide pin 10 was produced by cutting a piece of stainless steel (SUS304WPB) having a cross-sectional diameter of about 3.2 mm and a length of about 340 mm.

This guide pin 10 has an appearance as shown in FIG. 4-1, and has a total length of about 340 mm, a tip portion 12 of about 30 mm, and a shaft portion 11 of about 310 mm. Both the cross-sectional shapes of the tip portion and the shaft portion are circular. The cross-sectional diameter of the tip portion 12 is constant at about 3.0 mm at any point, and the cross-sectional diameter of the shaft portion 11 is constant at about 3.2 mm at any point. Also, as shown in FIG. 4-3, the tail portion of the shaft portion is formed with a constricted portion for coupling with the electric motor. The cross-sectional shape of the tail portion of the shaft portion 11 from the distal end to about 14 mm is machined into a shape in which three circular arcs are cut off at equal intervals, as shown in FIG. 4-4. As shown in FIG. 4-5, the distal end of the tip portion 12 is cut to form a substantially triangular pyramidal blade.

A case of treating a femoral neck fracture as shown in FIG. 2 using the guide pin 10 will be described. First, according to a known treatment method, the fracture site is reduced, and then the medullary canal of the femur is reamed from the top of the femoral head along the bone axis 24 under X-ray fluoroscopy. A rod (not shown) is inserted. In this case, the nail is embedded in the direction of the bone axis 24 (longitudinal direction).

Next, as shown in FIG. 2, a guide pin 22 (corresponding to the guide pin 10) is inserted so as to be substantially perpendicular to the femoral neck fracture . At this time, the guide pin is inserted from the lateral side of the femur, passes through (intersects) an insertion hole provided in the nail, and is inserted into the femoral neck fracture 23 . A series of these operations can also be performed using a known or commercially available tool such as a targeting device (targeting guide) capable of assisting positioning and fixing of each member.

Thereafter, a hollow drill (hollow reamer) 25 is used to pass the guide pin 22 through the hollow portion 25a thereof, and then the hollow drill is driven to perforate the bone. This creates a larger lumen where the guide pin is inserted. After the hollow drill 25 is removed, a lag screw (not shown) is inserted along the guide pin 22 while the guide pin 22 remains, and is embedded so as to be substantially perpendicular to the cross section of the femoral neck fracture 23. . The lag screw is also hollow, and is inserted so as to straddle the femoral neck fracture 23 in such a manner that the guide pin 22 is passed through the hollow portion. Thereby, the femoral neck fracture 23 can be fixed.

After confirming that the lag screw is in place, the guide pin 22 is removed. After the guide pin 22 is removed, the wound is closed by suturing the skin, and necessary measures such as protection with a bandage are taken to complete the operation.

Claims (6)

A guide pin for use in bone drilling, comprising:
(1) The guide pin has a tip portion on the tip side in the traveling direction and a shaft portion connected to the tip portion,
(2) A blade is formed at the end of the tip,
(3) the cross-sectional diameter of the tip is smaller than the cross-sectional diameter of the shaft;
A surgical guide pin characterized by: The surgical guide pin according to claim 1, wherein the cross-sectional diameter of the tip portion is 92-98% of the cross-sectional diameter of the shaft portion. The surgical guide pin of claim 1, wherein the cross-sectional diameter of the tip portion continuously decreases toward the blade portion. The surgical guide pin according to any one of claims 1 to 3, wherein the shaft portion has a cross-sectional diameter of 2.5 to 3.5 mm. The surgical guide pin according to any one of claims 1 to 4, wherein the length of the tip portion is 5 to 25% of the total length of the guide pin. The surgical guide pin according to any one of claims 1 to 5, which is non-threaded.

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