Body tissue perforation device

Abstract

To provide a body tissue perforation device sufficiently transmitting to a hand, a sensation of a distal end coming into contact with a perforation site.SOLUTION: A body tissue perforation device comprises a shaft 110 including a curved part 110A on the distal side and a straight part 110B on a proximal side; and a perforation head 130 formed at the distal end of the shaft 110 for denaturing and perforating biological tissue. The shaft 110 is formed of a tubular body being continuous from the distal end to the proximal end, and includes, on an outer face of the tubular body, a stepped part 115A whose outer diameter is larger than that of a portion on the distal side, provided at a prescribed distance from the distal end.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to body tissue-piercing devices. [Background technology]

[0002] Conventionally, one of the treatments for atrial fibrillation has been to cauterize the appropriate area in the left atrium with an ablation catheter. The ablation catheter may be inserted from the right atrium to the left atrium through the interatrial septum. In this case, a patent hole penetrating the interatrial septum is first created by atrial septal puncture (Brockenbrough procedure).

[0003] In the Brockenbrough technique, a dilator is inserted through the inferior vena cava, the tip of the dilator is placed against the fossa ovalis of the interatrial septum, and the fossa ovalis is pushed toward the left atrium, deforming it. Next, a perforation device is inserted through the dilator to perforate the fossa ovalis, creating a patent foramen.

[0004] The perforation devices used in the Brockenbrough method include a puncture needle that performs perforation by mechanical puncture, and an RF needle that performs perforation using high-frequency energy (see, for example, Patent Document 1). An RF needle performs perforation by denaturing biological tissue with high-frequency energy output from a perforation head. For this reason, it is safer than a puncture needle that requires a sharp tip, and the use of RF needles is increasing.

[0005] By providing a curved tip portion, including the drilling head portion, of a drilling device, it becomes easier to deliver it to the position of the fossa ovalis. However, when delivering the drilling device to the position of the fossa ovalis through a dilator or the like, the shape of the curved tip portion may interfere with the dilator, increasing sliding resistance and making insertion difficult or causing the dilator to move. For this reason, it has been studied to provide a flexible portion with low bending rigidity in the curved portion of the drilling device to facilitate movement of the drilling device within the dilator (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Republished Patent No. 2018 / 163899 Summary of the Invention

[0007] Drilling using an RF needle is performed by pressing the drilling head against the drilling site with an appropriate force. Whether the drilling head is in contact with the drilling site cannot be visually confirmed, so it must be determined by the feeling transmitted to the hand. For this reason, it is necessary to ensure that the feeling of the drilling head contacting and pressing against the drilling site is transmitted to the hand.

[0008] On the other hand, the direction of the force generated when the drilling head of the curved shaft abuts against the drilling site is different from the direction in which the base end of the shaft extends, making it difficult for the sensation of the drilling head to be transmitted to the base end. If a flexible part is provided at the curved part, the flexible part also functions as a cushion, making it even more difficult for the sensation to be transmitted.

[0009] In addition, the shaft of the drilling device has a short, thin tip connected to the tip of the long shaft body to make the part protruding from the dilator thinner. The connecting part also functions as a cushion, making it even more difficult for the sensation of the drilling head to be transmitted to the base end of the shaft.

[0010] An object of the present disclosure is to realize a puncture device in which the feel of the drilling head is sufficiently transmitted to the hand. [Means for solving the problem]

[0011] A first aspect of the body tissue perforation device of the present disclosure comprises a shaft having a curved portion at the tip end and a straight portion at the base end, and a perforation head formed at the tip of the shaft for denaturing and perforating biological tissue, the shaft having an outer shaft at the base end and an inner shaft inserted and connected to the outer shaft so that its tip portion protrudes from the outer shaft, and the base end of the inner shaft reaches the straight portion.

[0012] According to the first aspect of the tissue perforation device, the base end of the inner shaft reaches the straight portion, so that the force generated when the perforation head contacts the perforation site is transmitted to the straight portion via the inner shaft, allowing the sensation of the tip to be fully transmitted to the hand.

[0013] In a first aspect of the body tissue perforation device, the outer shaft may have an easily deformable portion formed in at least a part of the curved portion, the thickness of which in a first radial direction along the radius of curvature of the curved portion is thinner than the thickness in a second radial direction perpendicular to the first radial direction. With this configuration, the sensation of the tip is sufficiently transmitted to the hand, and the curved portion is easily deformed, facilitating the passage of a dilator.

[0014] A second aspect of the body tissue perforation device comprises a shaft having a curved portion at the tip end and a straight portion at the base end, and a perforation head formed at the tip of the shaft for denaturing and perforating biological tissue, the shaft consisting of a continuous tubular body from the tip to the base end, and the outer surface of the tubular body having a stepped portion at a predetermined distance from the tip, the outer diameter of which is larger than that of the tip end portion.

[0015] According to the second aspect of the body tissue perforation device, the shaft is a continuous tube from the tip to the base end, allowing the sensation of the tip to be fully transmitted to the hand. In addition, the stepped portion allows the length of protrusion of the perforation head from the dilator to be controlled.

[0016] In the second aspect of the body tissue-perforating device, the step portion can be formed by a ring-shaped member fixed to the outside of the tubular body. With this configuration, the step portion can be easily formed. [Effects of the Invention]

[0017] According to the body tissue perforation device of the present disclosure, the sensation of the tip contacting the perforation site is transmitted sufficiently to the hand, greatly improving operability and safety. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a side view of a drilling device according to one embodiment; [Figure 2] 1 is a cross-sectional view showing the tip of a perforation device according to one embodiment. FIG. [Figure 3] 1 is a cross-sectional view showing an embodiment of a perforation device combined with a sheath assembly. [Figure 4] FIG. 1 is a cross-sectional view showing an example of a dilator. [Figure 5] FIG. 2 is a cross-sectional view showing an example of an outer sheath. [Figure 6] FIG. 10 is a side view showing a first modified example of the perforation device. [Figure 7] FIG. [Figure 8] FIG. 10 is a side view showing a second modified example of the perforation device. DETAILED DESCRIPTION OF THE INVENTION

[0019] As shown in Figures 1 and 2, one embodiment of the body tissue perforation device 100 is an RF needle, and has a hollow shaft 110, a perforation head 130 provided at the tip of the shaft 110, and an operating portion 150 provided at the base end of the shaft 110.

[0020] The shaft 110 has an outer shaft 111 connected to the operating section 150 at its base end, and an inner shaft 112 that is thinner than the outer shaft 111 and protrudes toward the tip end. The tip end of the shaft 110, which includes the drilling head section 130, is a curved section 110A, and the base end side is a straight section 110B.

[0021] The outer shaft 111 and the inner shaft 112 are hollow cylindrical, and the outer diameter of the inner shaft 112 is approximately equal to the inner diameter of the outer shaft 111. The inner shaft 112 is inserted into the outer shaft 111 so that the inner shaft base end 112B reaches the straight portion 110B. The inner shaft tip 112A, on which the drilling head 130 is formed, protrudes further distally than the tip of the outer shaft 111. In this embodiment, the outer shaft 111 and the inner shaft 112 are made of metal such as stainless steel, and the inner shaft 112 is fixed to the outer shaft 111 by spot welding or the like.

[0022] The overall length of the shaft 110 is approximately 350 mm to 1800 mm, depending on the mode in which the instrument is used. The length of the curved portion 110A is preferably approximately 20 to 100 mm when performing drilling of the fossa ovalis, depending on the mode in which the instrument is used. Furthermore, the ratio (L2 / L1) of the length L1 from the base end to the tip of the curved portion 110A in the direction in which the straight portion 110B extends to the length L2 from the base end to the tip of the curved portion 110A in a direction perpendicular to L1 is preferably approximately 0.5 to 1.2. The curved portion 110A may be curved with a constant curvature as a whole, or the curvature may gradually increase or decrease. Furthermore, the curved portion 110A may have a straight portion on the tip side that is not curved.

[0023] From the viewpoints of strength, deformability, drug solution supplyability, etc., the outer shaft 111 preferably has an outer diameter of about 0.8 mm to 1.5 mm and a wall thickness of about 0.15 mm to 0.4 mm. From the viewpoints of strength, deformability, drug solution supplyability, etc., the inner shaft preferably has a wall thickness of about 0.1 mm to 0.3 mm.

[0024] The drilling head 130 is provided to close the inner shaft tip 112A, and high-frequency energy is output from the drilling head 130. The drilling head 130 can be formed, for example, from platinum or gold, or by gold-plating the surface. The drilling head 130 preferably has a curved tip surface without corners, so that it is less likely to get caught when moving through a lumen. For example, the drilling head 130 can have a substantially hemispherical shape that is convex toward the tip, or a bullet-like shape. In this embodiment, the shaft 110 is conductive and functions as an electrical circuit that supplies high-frequency current to the drilling head 130. If the shaft 110 is conductive, an insulating layer (not shown) made of an electrically insulating material such as synthetic resin is provided on its outer surface.

[0025] 3 to 5, the perforation device 100 of this embodiment is used in a procedure (Brockenbrough method) for forming a patent foramen in the fossa ovalis of the atrial septum in combination with a sheath assembly 200. The sheath assembly 200 has a dilator 210 into which the perforation device 100 is inserted, and an outer sheath 220 into which the dilator 210 is inserted.

[0026] In an example of the Brockenbrough technique, the practitioner first inserts the sheath assembly 200 into the right atrium along a guidewire that has been previously inserted into a body lumen such as a blood vessel. Next, the practitioner removes the guidewire and inserts the perforation device 100 into the dilator 210 to advance the perforation head 130 into the right atrium. Next, the practitioner causes the perforation head 130 to protrude from the tip of the dilator 210 and presses it against the fossa ovalis of the atrial septum. After that, the practitioner supplies high-frequency energy to the perforation head 130 pressed against the fossa ovalis to cauterize the fossa ovalis and form a hole. Thereafter, the practitioner advances the sheath assembly 200 into the left atrium while pushing open the hole with the tapered tip of the sheath assembly 200.

[0027] The sheath assembly 200 has a curved portion on the distal end side that roughly matches the curved portion 110A of the shaft 110. Providing the curved portion makes it possible to easily direct the distal end of the dilator 210 toward the fossa ovalis, facilitating perforation of the fossa ovalis with the perforation device 100 and insertion of the sheath assembly 200 into the left atrium.

[0028] When cauterizing the fossa ovalis, the perforation head 130 of the perforation device 100 must protrude from the tip of the dilator 210. However, if the perforation head 130 protrudes too far, there is a risk of damaging the inside of the atrium. For this reason, in this embodiment, as shown in Fig. 4, a dilator small-diameter portion 213 is provided at the tip of the dilator 210, the inner diameter of which is smaller than the outer diameter of the outer shaft 111 and larger than the outer diameter of the inner shaft 112. The outer shaft 111 abuts against a step 215 of the dilator small-diameter portion 213 and cannot enter the dilator small-diameter portion 213, so the protrusion length of the perforation head 130 from the tip of the dilator 210 can be limited.

[0029] The length of the part of the inner shaft 112 protruding from the outer shaft 111 is preferably about 10 mm to 30 mm, although this depends on the mode in which the instrument is used. In this case, the length of the dilator small diameter part 213 is preferably about 5 mm to 10 mm shorter than the length of the protruding part of the inner shaft so that the length of the drilling head 130 is about 0.5 mm to 3 mm.

[0030] Furthermore, when drilling, the drilling head 130 must be positioned by feel so that it abuts the fossa ovalis. Therefore, it is necessary to ensure that the sensation of the drilling head 130 abutting the fossa ovalis, which is thinner and softer than other parts, is sufficiently transmitted to the practitioner's hand. However, the direction (vector) of the force generated when the drilling head 130 provided at the tip of the curved portion 110A abuts the fossa ovalis does not coincide with the direction of extension of the linear portion 110B. Therefore, the sensation of the drilling head 130 abutting the fossa ovalis is not easily transmitted to the operating unit 150. Furthermore, the shaft 110 is configured such that the inner shaft 112 is connected to the tip of the outer shaft 111 to form a step that prevents the shaft from slipping out. When two shafts are connected, the force is easily absorbed at the connecting portion, making it even more difficult for the sensation to be transmitted to the practitioner's hand.

[0031] However, in this embodiment, the inner shaft base end 112B is inserted to a position beyond the curved portion 110A and reaches the straight portion 110B. Therefore, the force generated when the drilling head 130 abuts against the fossa ovalis is transmitted to the straight portion 110B of the outer shaft 111 via the inner shaft 112. Therefore, the feeling of the drilling head 130 abutting against the fossa ovalis is sufficiently transmitted all the way to the practitioner's hand.

[0032] The inner shaft 112 can be fixed to the outer shaft 111 by spot welding. Increasing the number of spot welding locations reduces the absorption of force at the connecting portion, making it easier to transmit tactile sensations to the hand. Increasing the insertion length of the inner shaft 112 into the outer shaft 111 makes it easy to increase the number of axial welding locations. The location of spot welding can be determined taking into account factors such as manufacturing costs. However, from the perspective of facilitating force transmission, spot welding can be performed at multiple locations with circumferentially offset positions. Spot welding can also be performed at multiple locations with axially offset positions. When axially offsetting positions is used, it is preferable to weld the most distal and proximal ends of the overlapping portion between the inner shaft 112 and the outer shaft 111. Furthermore, spot welding can be performed with offset positions both circumferentially and axially. Note that the inner shaft 112 can be fixed to the outer shaft 111 not only by spot welding, but also by laser welding in a ring or spiral shape, or by fixing the entire overlapping portion. Fixation can also be performed by methods other than welding, such as adhesive bonding.

[0033] The inner shaft proximal end 112B may extend beyond the boundary between the curved portion 110A and the straight portion 110B and reach the straight portion 110B side. Furthermore, the inner shaft proximal end 112B may extend to the proximal end of the outer shaft 111. A spiral slit may be provided in a portion of the inner shaft 112. Depending on the material and thickness of the inner shaft 112, the stiffness of the shaft may become too high, which may increase the resistance when the curved portion 110A of the shaft 110 passes through the dilator 210 or may even prevent it from passing through. By providing a spiral slit in at least a portion of the curved portion of the inner shaft 112, it is possible to transmit the sensation of the drilling head 130 contacting the drilling site to the hand, while suppressing an increase in the stiffness of the shaft 110.

[0034] The inner shaft 112 having a spiral slit can be formed by laser processing or the like. The inner shaft 112 is not limited to a spiral slit, and can also be formed in a mesh shape or the like. Alternatively, the inner shaft 112 can have a structure in which a thin rod-shaped member extends toward the base end.

[0035] If it is desired to further reduce the bending rigidity of bending portion 110A, it is possible to provide a deformable portion 111C by thinning a portion of outer shaft 111 in at least a part of bending portion 110A, as in the first modified example shown in Fig. 6. Even in this case, because inner shaft 112 extends to straight portion 110B, even if deformable portion 111C is provided on outer shaft 111 in bending portion 110A, the feeling of drilling head 130 coming into contact with the drilling site can be sufficiently transmitted to the hand.

[0036] In this modification, the outer surface of the easily deformable portion 111C is polished in the direction of the radius of curvature R of the bending portion 110A. As shown in FIG. 7, the thickness t1 in the first radial direction D1 along the direction of the radius of curvature R is thinner than the thickness t2 in the second radial direction D2 perpendicular to the first radial direction D1. Therefore, deformation is likely to occur in the direction that changes the curvature of the bending portion 110A, but bending rigidity is maintained in other directions. This allows for easy passage through the dilator 210 while maintaining rigidity that enables pressing against the fossa ovalis. However, if a balance between deformability and rigidity can be achieved, the easily deformable portion 111C may be thinned by grinding the entire circumference of the outer shaft 111.

[0037] In a typical drilling device, the thickness of the outer shaft 111 is approximately 0.15 mm to 0.4 mm, and it is preferable that the thickness in the first radial direction of the easily deformable portion 111C provided in the curved portion into which the inner shaft 112 is inserted be 25% to 70% of that, from the viewpoint of achieving both deformability and strength.

[0038] As shown in FIG. 7 , the shaft 110 may be configured as a continuous tube from its distal end to its proximal end, with a ring-shaped member 115 fixed at a predetermined position from the distal end to provide a stepped portion 115A with a larger outer diameter than the distal portion. Because the shaft 110 is made of a single member from its distal end to its proximal end, the sensation of the drilling head 130 touching the drilling site can be more easily transmitted to the proximal end. Furthermore, the stepped portion 115A acts as a retainer, allowing for control of the length of protrusion of the drilling head 130 from the dilator 210. The stepped portion 115A need only function as a retainer, and may be formed by one or more protrusions rather than a continuous ring. Instead of fixing another member to the outside of the tube, the stepped portion 115A may be formed by deforming the outer surface of the tube, or by thinning the portion distal to the stepped portion by grinding or the like.

[0039] The operating part 150 provided at the base end of the shaft 110 may have any shape as long as it can be gripped and used to operate the shaft 110. By passing the operating part 150 through the shaft 110 and fixing it, the feel of the drilling head 130 can be more easily transmitted to the practitioner. However, as long as the feel can be transmitted to the practitioner's hand, the shaft 110 does not have to pass through the operating part 150.

[0040] The operation unit 150 is provided with a power connector 152 for connection to a high-frequency power supply device. The power connector 152 is connected to the metal shaft 110 via a current-carrying cable 153, and can pass a high-frequency current through the shaft 110.

[0041] A liquid connector 155 to which a syringe or the like can be connected is provided at the base end of the operation unit 150. An opening 112a is provided at the tip end of the shaft 110, and a medicinal liquid such as saline or contrast agent injected from the liquid connector 155 can be sent to the treatment site through the inner cavity of the shaft 110.

[0042] The dilator 210 into which the perforation device 100 of this embodiment is inserted is a hollow tubular body having an inner cavity 214, and has a dilator curved portion 216 on the tip side. The dilator 210 can be formed from a flexible resin or the like. It is preferable that the dilator curved portion 216 be curved in a manner that is substantially identical to the curved portion 110A of the perforation device 100, so as to facilitate insertion of the perforation device 100 and to facilitate operation of the perforation device while it is inserted.

[0043] A dilator tapered section 212 that tapers in diameter toward the tip side is formed at the tip of the dilator 210. The dilator tapered section 212 can widen the hole in the fossa ovalis formed by the perforation device 100.

[0044] The dilator 210 has a dilator small diameter section 213 whose inner diameter is slightly larger than the outer diameter of the inner shaft 112 of the perforation device 100 and smaller than the outer diameter of the outer shaft 111. A step 215 is formed at the base end of the dilator small diameter section 213. The inner shaft 112 of the perforation device 100 can enter the dilator small diameter section 213, but the outer shaft 111 abuts against the step 215 and cannot enter. The step 215 only needs to abut against the tip of the outer shaft 111, and may be inclined toward the central axis of the dilator 210.

[0045] A dilator connector 211 that can be connected to a Y connector or the like is provided at the base end of the dilator 210. The dilator connector 211 may be integrally molded with other parts of the dilator 210, or a separately molded member may be fixed.

[0046] The outer sheath 220 into which the dilator 210 is inserted has a sheath body 221 and a hub 224 provided at the proximal end of the sheath body 221.

[0047] The sheath body 221 is a long tubular body and has a sheath bending section 222 on the distal end side. The bending angle of the sheath bending section 222 preferably approximately matches the bending angle of the dilator bending section 216. Furthermore, when the dilator 210 is inserted into the outer sheath 220 to form a sheath assembly, it is preferable that the bending start position and bending direction of the dilator bending section 216 and the sheath bending section 222 approximately match. The sheath body 221 can be formed from a flexible resin or the like.

[0048] A sheath tapered portion 223 that gradually reduces in diameter toward the distal end is provided at the distal end of the sheath body 221. When the dilator 210 is inserted into the outer sheath 220 to form the sheath assembly 200, the dilator tapered portion 212 and the sheath tapered portion 223 preferably have a substantially continuous tapered shape. This allows the dilator tapered portion 212 and the sheath tapered portion 223 to enlarge the hole formed in the fossa ovalis, allowing the outer sheath 220 to enter the left ventricle.

[0049] The hub 224 is provided at the proximal end of the sheath body 221 and has a valve body 225 that closes the inner cavity of the sheath body 221. The valve body 225 can be expanded by pressing, allowing the dilator 210 to be inserted. When the dilator is withdrawn, the valve body 225 closes, preventing blood from leaking out of the sheath body 221 and air from entering the body. The hub 224 can be made of resin or the like, but is preferably made more rigid than the sheath body 221 to facilitate insertion and withdrawal of the dilator 210. The valve body can be made of an elastic material such as rubber or elastomer.

[0050] A sheath port 227 to which a syringe or the like can be connected is connected to the hub 224 via a liquid line 226. The sheath port 227 can be used to prime the inside of the sheath body 221 or to inject a drug such as a contrast agent.

[0051] In this embodiment, shaft 110 is made of a metal material such as stainless steel, and functions as an electrical circuit that supplies high-frequency current to drilling head 130. However, a configuration in which wiring that supplies high-frequency current to drilling head 130 is provided separately from shaft 110 may also be used. In this case, shaft 110 may be made insulating, and may be made of various resin materials. If shaft 110 is made insulating, it is not necessary to form an insulating layer that covers the outer surface of shaft 110. Furthermore, current-carrying cable 153 that connects to a high-frequency power source may simply be connected to the wiring.

[0052] Alternatively, one of the outer shaft 111 and the inner shaft 112 may be made of metal and the other may be made of an insulating material such as resin. If the outer shaft 111 is made of resin and the inner shaft 112 made of metal is inserted up to the base end of the outer shaft 111, the outer shaft 111 can be used as an insulating layer and the inner shaft 112 can be used as an electrical circuit.

[0053] The shaft 110 preferably has a degree of deformability that allows deformation and restoration when passing through the dilator, and also allows the practitioner to bend it by hand and shape it. [Industrial Applicability]

[0054] The tissue perforation device of the present disclosure allows the sensation of the tip contacting the perforation site to be fully transmitted to the hand, greatly improving operability and safety, and is useful in cardiac surgery and the like. [Explanation of symbols]

[0055] 100 Perforation Device 110 Shaft 110A curved section 110B Straight section 111 outer shaft 111C Deformable part 112 Inner Shaft 112A Inner Shaft Tip 112B Inner shaft base end 112a aperture 115 Ring-shaped part 115A Step 130 Drilling head 150 Operation section 152 Power Connector 153 Electrical Cable 155 Liquid Connector 200 Sheath assembly 210 Dilator 211 Dilator Connector 212 Dilator tapered part 213 Dilator small diameter part 214 Lumen 215 steps 216 Dilator curved part 220 Outer sheath 221 Sheath body 222 Sheath bending section 223 Sheath taper part 224 Hub 225 Valve body 226 Liquid Line 227 Seaport

Claims

1. a shaft having a curved portion provided on the distal end side and a straight portion provided on the proximal end side; a drilling head formed at the tip of the shaft for denaturing and drilling biological tissue; The shaft is made of a continuous tube from the distal end to the proximal end, A body tissue perforation device, wherein the outer surface of the tubular body has a stepped portion at a position a predetermined distance from the tip, the stepped portion having an outer diameter larger than that of the tip portion.

2. The body tissue perforation device according to claim 1 , wherein the step portion is formed by a ring-shaped member fixed to the outside of the tubular body.

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