Medical instrument

The present invention relates to a medical device used for reinsertion and dilation of an occluded portion and a stenotic portion in a blood vessel.

Conventionally, reinsertion and dilation of an occluded part and a stenotic part in a blood vessel are performed by a catheter having an dilator at the tip, a small-diameter microcatheter, or an atherectomy catheter aiming at a cutting effect (see Patent Document 1). There is.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 7-265319</text></patcit>

<p> The dilated catheter and the microcatheter are inserted through a guide catheter, and both are inserted into the target site mainly by a pushing force. For this reason, when the occluded portion and the stenotic portion are strong, even if the pushing force is forcibly transmitted, the guide catheter is simply pulled out, and reinsertion and expansion are difficult. Also, atherectomy catheters have no effect on relatively flexible tissues and can only be applied to hard, calcified lesions. An object of the present invention is to provide a medical device that can more reliably pass through a lesion in which an extended device or the like after passing through a guide wire is difficult to pass through.</p>

<p> The medical device according to claim 1 has a hollow body shaft, a tubular tip formed at the tip of the hollow body shaft, and a grip portion connected to the hand end side of the hollow body shaft, and at least. It is characterized in that screw-like irregularities are formed on either or both of the inner peripheral surface and the outer peripheral surface of the tip or the hollow shaft.</p><p> The invention according to claim 2 is characterized in that the tip is made of an X-ray impermeable material and is fused with the hollow shaft. In the invention according to claim 3, the screw-like unevenness of the hollow body shaft draws a plurality of spiral lines, and the lead length of the plurality of spiral wires is larger than the outer diameter of the hollow body shaft. It is characterized by. The invention according to claim 4 is characterized in that a portion made of a material having a lower yield load than any portion of the hollow body shaft is provided on the hand side of the hollow body shaft.</p><p> The invention according to claim 5 is characterized in that the hollow body shaft has an outer diameter or a cross-sectional area smaller than any portion of the hollow body shaft, or has the same reduced diameter portion on the hand side. The invention according to claim 6 is characterized in that the grip portion is provided with a fluoroscopic portion in which the reduced diameter portion of the hollow body shaft or a portion made of a material having a low yield load can be visually recognized.</p>

The best embodiments of the present invention will be described with Examples 1 and 2.

(A) of FIG. 1 shows the medical device 1 of the first embodiment, and (b) to (nu) of FIG. 1 show an enlarged view of a cross section and a main part. The medical device 1 includes a flexible hollow body shaft 2 formed by spiraling a plurality of strands 21 into a cylindrical shape, a tubular tip tip 3 fused to the tip of the hollow body shaft 2, and a hollow body. It is composed of a handle member 4 connected to the hand end side of the shaft 2.

As shown in (a) of FIG. 2, the hollow shaft 2 has a structure in which eight stainless steel strands 21 are spirally wound so that the lead length is 1.2 mm in this embodiment, and has an outer diameter. Is 0.70 mm and the length is about 1350 mm. The tip of the hollow shaft 2 is provided with a tip-side reduced diameter portion 22 formed by reducing the diameter of the outer circumference by grinding or the like. In this embodiment, the tip-side reduced diameter portion 22 is a cylinder having an outer diameter of 0.62 mm, and includes a straight portion 23 having a length of 10 mm and a tapered portion 24 having a length of 150 mm. The hollow shaft 20 of another embodiment shown in FIG. 2 (b) includes a straight portion 23 having a length of 80 mm and a tapered portion 24 having a length of 50 mm.

It is effective that the hollow body shaft 2 of this embodiment has a continuous or discontinuous cross-sectional area toward the tip, as in the tip-side reduced diameter portion 22, and is made of metal from the viewpoint of rotational transmissibility. It is desirable that the tensile strength of the material is 120 kgf / square millimeter or more. Further, a bulging portion may be provided in the middle of the hollow body shaft 2. The hollow shaft 2 may have a structure in which spiral strips are formed on the outer periphery of a cylindrical pipe such as a stainless steel pipe, and the strand 21 may be a NiTi alloy wire.

At the rear end portion of the hollow body shaft 2, a rear end side reduced diameter portion 25 made of a cylinder having an outer diameter of 0.62 mm and a length of 85 mm is formed. The outer diameter of the rear end side reduced diameter portion 25 is set to be equal to or less than the front end side reduced diameter portion 22. This is to ensure that torsional buckling occurs preferentially in the rear end side reduced diameter portion 25 during use. The number of strands 21, the outer diameter, and the lead length are design items that are appropriately set, but it is advantageous that the lead length is larger than the outer diameter from the viewpoint of screwing efficiency. Further, the hollow body shaft 2 may be a close contact coil spring in which a single wire is coiled.

The tip 3 is made of a platinum cylinder and has an outer diameter of 0.62 mm, a length of approximately 1 mm, and a tapered portion 31 on the tip side of 1/10. The tip 3 acts as a cylindrical cutting edge (hollow cone) for drilling a hole in a closed or narrowed portion. Therefore, it is desirable that the tapered tapered portion 31 has a taper of 1/2 or more of the total length of the tip tip 3 and a taper of 1/9 to 1/12. Screw-shaped irregularities may be provided on the inner peripheral surface or the outer peripheral surface of the tip tip 3, and it is desirable that the lead length of the screw is larger than the outer diameter from the viewpoint of screwing efficiency.

The hollow body shaft 2 is covered with a cover tube 26 having a length of 350 mm from the hand side portion of the hollow body shaft 2 in front of the rear end side reduced diameter portion 25 to the front side portion of the rear end side reduced diameter portion 25. There is. A stainless steel round protective pipe 27 is externally fitted and fixed to the rear side of the reduced diameter portion 25 on the rear end side, and a square protective pipe 28 is externally fitted and fixed to the rear side (hand side) of the round protective pipe 26. Has been done.

As shown in FIG. 1 (i), a slightly larger transparent cylinder portion 29 is provided on the front side portion of the rear end side reduced diameter portion 25 of the cover tube 26, and the rear end side reduced diameter portion 25 is provided from the outside. Is a see-through unit 10 that can be visually recognized. The fluoroscopic portion 10 is formed by providing a missing portion in the cover tube 26 instead of the transparent tubular portion 29 integrated with the cover tube 26, and externally fitting a transparent tube having a slightly large diameter in the missing portion. May be good. As a result, the rear end side reduced diameter portion 25 in the fluoroscopic portion 10 has a small gap in the transparent tubular portion 29 that allows buckling deformation such as torsional buckling, and is visible from the outside.

The handle member 4 is composed of a cylindrical protector 41 having a tapered tip side, a small diameter tip portion 42 fitted to the rear end portion of the protector 41, and a cylindrical connector 43 having fins F and F on the outer circumference. Become. The small-diameter tip portion 42 is fitted and fixed to the corner protection pipe 28, and the handle member 4 rotates integrally with the rear end portion of the hollow body shaft 2.

The medical device 1 of this embodiment is inserted into a blood vessel and the tip tip 3 abuts against the lesion in an operation for drilling a lesion such as an occlusion of a coronary artery, so that the handle member 4 is pushed and twisted. It is operated as. Rotation is applied to the hollow body shaft 2 to exert a screw effect at a contact point with a lesion or a contact point with a blood vessel or a guide medical device, and the medical device 1 can be screwed in and pulled out depending on the direction of rotation. Even without a backup of the guide catheter, it can pass through the lesion without being pushed hard, and can be reinserted and dilated by the dotter effect of the passage.

The hollow shaft 2 has a greater screwing effect when the screw pitch is high, and sufficient torque cannot be transmitted unless a material (wire) having a relatively high tensile strength is used. Further, the more flexible the hollow shaft 2, the easier it is to follow the flexion lesion and the easier it is to pass through, but the more flexible the shaft 2 is, the lower the torque transmission force is. Therefore, in this embodiment, a 160 mm tip side reduced diameter portion 22 is provided at the tip portion entering the bent portion to gradually reduce the cross-sectional area, and increase the torque transmission force on the hand side while ensuring the flexibility of the tip portion. , Achieves both passability and torque transmission. The tip side reduced diameter portion 22 is appropriately in the range of 100 mm to 300 mm, and the presence of the straight portion 23 further improves the passability.

Further, since the tip 3 is fused and integrated with the hollow body shaft 2, the physical dimensions and characteristics of the hollow body shaft 2 are not impaired. Further, since the tip tip 3 has a 1/10 tapered portion 31 and is hollow, the tip tip 3 is sure to invade the center of the tissue of the closed portion and a part of the tissue of the closed portion to be drilled is the tip tip. Since it enters the inside of 3, it is possible to smoothly drill holes in the tissue of the closed part. If the bulge is provided, the dotter effect when passing through is large, and a larger expansion becomes possible.

If the closed portion is tough, the hollow shaft 2 may be loosened or twisted and buckled. As shown in FIG. 2B, in the hollow shaft 20 not provided with the rear end side reduced diameter portion 25, torsional buckling is likely to occur at the tip side reduced diameter portion 22 such as the straight portion 23 or the tapered tapered portion 24. If twist buckling or the like occurs in the tip side reduced diameter portion 22, the operation of pulling out the medical device 1 for replacement becomes troublesome, and a safety problem arises.

In the hollow body shaft 2 shown in FIG. 2 (a) of this embodiment, as shown in FIG. 3, the rear end side reduced diameter portion 25 is preferentially buckled and deformed, and the tip portion of the hollow body shaft 2 and other blood vessels Safety is improved because problems such as twisting and buckling inside can be reliably prevented. Further, the fluoroscopic unit 10 has an effect that the operator can visually recognize this torsional buckling and can prevent a problem that the operator is injured by a broken piece of the hollow body shaft 2.

FIG. 4 shows the medical device 5 of the second embodiment. In the medical device 5, the tip tip 7 is fixed to the tip of the hollow shaft 6, and the handle member 8 is connected to the rear end. In this embodiment, the hollow body shaft 6 is composed of a lower layer resin layer 62 made of a polyamide elastomer in which a braided stainless steel wire 61 is embedded, and an upper layer resin 63 made of only a polyamide elastomer coated on the outer periphery of the lower layer resin layer 62. .. The hollow shaft 6 has an outer diameter of 0.70 mm and an inner diameter of 0.42 mm, forming a flexible tube. The rear end of the hollow shaft 6 is covered with a protective tube 64.

A tip 7 made of polyamide elastomer is bonded to the tip of the hollow shaft 6. The tip 7 has the same inner diameter as the lower resin layer 62 and the same outer diameter as the upper resin 63. At the rear side of the tip tip 7, there is a thin-walled portion 74 that fits outside the tip of the lower resin layer 62, and it is practical to bond with an adhesive 84. A spiral ridge 75 having a height of 0.05 mm is formed on the outer periphery of the tip 7 and the hollow shaft 6 on the tip side with a lead of 1 mm and a pitch of 0.5 mm.

The handle member 8 includes a cylindrical protector 81 having a tapered tip side and a cylindrical connector 83 having a small-diameter tip 82 fitted to the rear end of the protector 81 and having fins F and F on the outer circumference. Consists of. The small-diameter tip portion 82 is fitted onto the rear end portion of the protective tube 64 and adhered with an adhesive 84, and rotates integrally with the rear end portion of the hollow body shaft 6.

The medical device 5 of this embodiment also has the same action and effect as that of the first embodiment, and the spiral ridge 75 can smoothly screw the blood vessel into the occluded portion.

<figref num="1">It is a front view, a cross-sectional view, and an enlarged view of a main part of a medical device (Example 1).</figref><figref num="2">It is a front view and a cross-sectional view of a hollow shaft (Example 1).</figref><figref num="3">It is an enlarged view of the main part of a medical device (Example 1).</figref><figref num="4">It is a front view, a cross-sectional view, and an enlarged view of a main part of a medical device (Example 2).</figref>

Code description

1 Medical device 10 Perspective part 2 Hollow body shaft 21 Wire 22 Tip side reduced diameter part 23 Straight part 24 Tapered tapered part 25 Rear end side reduced diameter part 3 Tip tip 31 Tapered tapered part 4 Handle member (grip part) 5 Medical device 6 Hollow body shaft 7 Tip tip 8 Handle member (grip part)