JP7729074B2 - Tissue-perforating device - Google Patents

Description

The present disclosure relates to a body tissue perforation device.

One of the traditional treatments for atrial fibrillation is to cauterize appropriate areas in the left atrium with an ablation catheter. The ablation catheter may be inserted from the right atrium to the left atrium through the atrial septum. In this case, a patent hole penetrating the atrial septum is first created by atrial septal puncture (Brockenbrough procedure).

In the Brockenbrough technique, a dilator is inserted through the inferior vena cava, the tip of the dilator is placed against the fossa ovalis in the atrial 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.

The perforation devices used in the Brockenbrough method include puncture needles, which perform perforation by mechanical puncture, and RF needles, which perform perforation using radiofrequency energy (see, for example, Patent Document 1). RF needles perform perforation by denaturing biological tissue with radiofrequency energy output from the perforation head. For this reason, they are safer than puncture needles, which require a sharp tip, and the use of RF needles is increasing.

By giving the tip, including the drilling head, a curved shape, the drilling device can be easily inserted into the fossa ovalis. However, when inserting the drilling device into a dilator or the like, the curved shape of the tip can interfere with the dilator, increasing sliding resistance and making insertion difficult, or even causing the dilator to move. For this reason, efforts are being made to provide the curved part of the drilling device with a flexible section with low bending rigidity, thereby making it easier to move the drilling device within the dilator (see, for example, Patent Document 1).

Republished Patent No. 2018/163899

Perforation using an RF needle is performed by pressing the perforation head against the perforation site with an appropriate amount of force. Whether the perforation head is in contact with the perforation site cannot be visually confirmed, so it must be determined by the feel transmitted to the hand. For this reason, it is necessary to ensure that the feel of the perforation head contacting the perforation site and applying pressure is transmitted to the hand.

However, the direction of the force generated when the drilling head of the curved shaft comes into contact with 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 section is provided in the curved section, the flexible section also functions as a cushion, making it even more difficult for the sensation to be transmitted.

In addition, to thin the portion of the shaft of the drilling device that protrudes from the dilator, a short, thin tip is attached to the end of the long shaft body. The connection also functions as a cushion, making it even less likely that the sensation of the drilling head will be transmitted to the base end of the shaft.

The objective of this disclosure is to create a puncture device that allows the sensation of the drilling head to be fully transmitted to the hand.

A first aspect of the body tissue perforation device disclosed herein comprises a shaft having a curved portion at the distal end and a straight portion at the proximal end, and a perforation head formed at the distal end of the shaft for perforating biological tissue by denaturing it. The shaft has an outer shaft at the proximal end and an inner shaft inserted and connected to the outer shaft so that its distal end protrudes from the outer shaft, and the proximal end of the inner shaft reaches the straight portion.

In the first aspect of the tissue perforation device, the base end of the inner shaft reaches the straight portion, so 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 touching the tip to be fully conveyed to the hand.

In the first aspect of the body tissue perforation device, the outer shaft may have an easily deformable section formed on at least a portion of the curved section, the thickness of which in a first radial direction along the radius of curvature of the curved section is thinner than the thickness in a second radial direction perpendicular to the first radial direction. This configuration allows the sensation of the tip to be fully transmitted to the hand, and the curved section is more easily deformed, facilitating the passage of a dilator.

A second aspect of the tissue perforation device comprises a shaft having a curved portion at the distal end and a straight portion at the proximal end, and a perforation head formed at the distal end of the shaft for perforating biological tissue by denaturing it. The shaft is made of a continuous tube from the distal end to the proximal end, and the outer surface of the tube has a stepped portion at a predetermined distance from the distal end, with an outer diameter greater than that of the distal end.

According to the second aspect of the tissue perforation device, the shaft is made of a continuous tube from the tip to the base end, allowing the sensation of the tip to be fully transmitted to the hand. Furthermore, the stepped portion allows the length by which the perforation head protrudes from the dilator to be controlled.

In the second aspect of the tissue-perforating device, the step portion can be formed by a ring-shaped member fixed to the outside of the tubular body. This configuration makes it easy to form the step portion.

With the body tissue perforation device disclosed herein, the sensation of the tip coming into contact with the perforation site is fully transmitted to the hand, greatly improving operability and safety.

1 is a side view of a drilling device according to one embodiment; 1 is a cross-sectional view showing the tip of a perforation device according to one embodiment. FIG. 1 is a cross-sectional view showing an embodiment of a perforation device combined with a sheath assembly. FIG. 1 is a cross-sectional view showing an example of a dilator. FIG. 2 is a cross-sectional view showing an example of an outer sheath. FIG. 10 is a side view showing a first modified example of the perforation device. FIG. FIG. 10 is a side view showing a second modified example of the perforation device.

As shown in Figures 1 and 2, the body tissue perforation device 100 of one embodiment 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 section 150 provided at the base end of the shaft 110.

The shaft 110 has an outer shaft 111 connected to the operating section 150 at the 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, including the drilling head 130, is a curved section 110A, and the base end is a straight section 110B.

The outer shaft 111 and 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 distally beyond the tip of the outer shaft 111. In this embodiment, the outer shaft 111 and 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.

The overall length of the shaft 110 is approximately 350 mm to 1800 mm, depending on the manner in which the instrument is used. When performing drilling of the fossa ovalis, the length of the curved portion 110A is preferably approximately 20 to 100 mm, depending on the manner 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. It may also have a straight, uncurved portion on the tip side.

From the standpoints of strength, deformability, and drug supply performance, the outer shaft 111 preferably has an outer diameter of approximately 0.8 mm to 1.5 mm and a wall thickness of approximately 0.15 mm to 0.4 mm. From the standpoints of strength, deformability, and drug supply performance, the inner shaft preferably has a wall thickness of approximately 0.1 mm to 0.3 mm.

The drilling head 130 is arranged 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 the lumen. For example, it can have a roughly 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, its outer surface is provided with an insulating layer (not shown) made of an electrically insulating material such as synthetic resin.

As shown in Figures 3 to 5, the perforation device 100 of this embodiment is combined with a sheath assembly 200 and used in a procedure (Brockenbrough procedure) to form a patent foramen in the fossa ovalis of the atrial septum. The sheath assembly 200 includes a dilator 210 into which the perforation device 100 is inserted, and an outer sheath 220 into which the dilator 210 is inserted.

In an example of the Brockenbrough procedure, 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 through the dilator 210, sending the perforation head 130 into the right atrium. Next, the practitioner protrudes the perforation head 130 from the tip of the dilator 210 and presses it against the fossa ovalis in 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. The tapered tip of the sheath assembly 200 then pushes open the hole while the sheath assembly 200 enters the left atrium.

The sheath assembly 200 has a curved portion at its distal end that roughly matches the curved portion 110A of the shaft 110. Providing this curved portion allows the distal end of the dilator 210 to easily face 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.

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 Figure 4, the tip of the dilator 210 is provided with a dilator small-diameter portion 213 whose inner diameter 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 in the dilator small-diameter portion 213 and cannot enter the dilator small-diameter portion 213, thereby limiting the length by which the perforation head 130 protrudes from the tip of the dilator 210.

The length of the portion of the inner shaft 112 that protrudes from the outer shaft 111 is preferably approximately 10 mm to 30 mm, depending on how the instrument is used. In this case, the length of the dilator small diameter portion 213 is preferably approximately 5 mm to 10 mm shorter than the length of the protruding portion of the inner shaft, so that the length of the drilling head 130 is approximately 0.5 mm to 3 mm.

Furthermore, when performing drilling, the drilling head 130 must be positioned by feel so that it abuts the fossa ovalis. For this reason, 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, located at the tip of the curved section 110A, abuts the fossa ovalis, does not match the direction of extension of the straight section 110B. For this reason, the sensation of the drilling head 130 abutting the fossa ovalis is not easily transmitted to the operating section 150. Furthermore, the shaft 110 is configured with an inner shaft 112 attached to the tip of the outer shaft 111 to form a step that prevents it from slipping out. When two shafts are attached, force is easily absorbed at the connection, making it even more difficult for the sensation to be transmitted to the practitioner's hand.

However, in this embodiment, the inner shaft base end 112B is inserted past the curved portion 110A to a position where it reaches the straight portion 110B. As a result, the force generated when the drilling head 130 contacts the fossa ovalis is transmitted via the inner shaft 112 to the straight portion 110B of the outer shaft 111. As a result, the sensation of the drilling head 130 contacting the fossa ovalis is fully transmitted to the practitioner's hand.

The inner shaft 112 can be fixed to the outer shaft 111 by spot welding. Increasing the number of spot welds reduces the absorption of force at the connection, 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 welds. The location of spot welds can be determined based on factors such as manufacturing costs. However, to facilitate force transmission, spot welding can be performed at multiple locations with circumferential offsets. Spot welding can also be performed at multiple locations with axial offsets. When axial offsets are 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 offsets in both the circumferential and axial directions. Note that the inner shaft 112 can be fixed to the outer shaft 111 by more than just spot welding; it can also be laser welded in a ring or spiral shape, or the entire overlapping portion can be fixed. Fixation can also be performed by methods other than welding, such as adhesive bonding.

The inner shaft base end 112B may extend beyond the boundary between the curved portion 110A and the straight portion 110B and reach the straight portion 110B. Furthermore, the inner shaft base end 112B may extend all the way to the base 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 shaft may become too rigid, resulting in increased resistance when the curved portion 110A of the shaft 110 passes through the dilator 210, or it may even be impossible to pass 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 minimizing an increase in the rigidity of the shaft 110.

The inner shaft 112 with a spiral slit can be formed by laser processing or the like. Furthermore, the inner shaft 112 is not limited to a spiral slit; it can also be made to have a mesh-like structure. It can also have a structure in which a thin rod-shaped member extends toward the base end.

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

In this modified example, the outer surface of the easily deformable portion 111C is polished in the direction of the radius of curvature R of the curved portion 110A, and 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 more likely to occur in the direction that changes the curvature of the curved portion 110A, but bending rigidity is maintained in other directions. This allows for easy passage through the dilator 210 while maintaining rigidity that allows pressure on 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.

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

As shown in the second modified example in Figure 7, the entire shaft 110 may be a continuous tube from its tip to its base end, with a ring-shaped member 115 fixed at a predetermined position from the tip 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 tip to its base end, the sensation of the drilling head 130 touching the drilling site can be more easily transmitted to the base 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 convex portions rather than a continuous ring. Furthermore, rather than 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.

The operating unit 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 unit 150 through and fixing the shaft 110, 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 unit 150.

The operating unit 150 is provided with a power connector 152 for connecting to a high-frequency power supply. The power connector 152 is connected to the metal shaft 110 via a current-carrying cable 153, allowing high-frequency current to flow through the shaft 110.

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

The dilator 210 into which the perforation device 100 of this embodiment is inserted is a hollow tube with an inner cavity 214 and has a dilator curved portion 216 at its tip. The dilator 210 can be formed from a flexible resin or the like. To facilitate insertion of the perforation device 100 and to facilitate operation of the perforation device while it is inserted, it is preferable that the dilator curved portion 216 be curved in a manner that is approximately the same as the curved portion 110A of the perforation device 100.

A dilator taper section 212 that tapers toward the tip is formed at the tip of the dilator 210. The dilator taper section 212 allows the opening in the fossa ovalis formed by the perforation device 100 to be widened.

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.

The base end of the dilator 210 is provided with a dilator connector 211 that can be connected to a Y connector or the like. The dilator connector 211 may be molded integrally with the rest of the dilator 210, or a separately molded component may be fixed to it.

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.

The sheath body 221 is a long tubular body with a sheath bending section 222 at its distal end. 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.

The tip of the sheath body 221 is provided with a sheath taper section 223 that gradually reduces in diameter toward the tip. When the dilator 210 is inserted into the outer sheath 220 to form the sheath assembly 200, it is preferable that the dilator taper section 212 and the sheath taper section 223 have a substantially continuous tapered shape. This allows the dilator taper section 212 and the sheath taper section 223 to enlarge the hole in the fossa ovalis, allowing the outer sheath 220 to enter the left ventricle.

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 other materials, but it is preferable that it have greater rigidity than the sheath body 221 to facilitate insertion and removal of the dilator 210. The valve body can be made of an elastic material such as rubber or elastomer.

A sheath port 227, which can be connected to a syringe or the like, 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 drugs such as contrast agents.

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

It is also possible to form one of the outer shaft 111 and the inner shaft 112 from metal and the other from an insulating material such as resin. If the outer shaft 111 is formed from resin and the inner shaft 112 made from 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 as an electrical circuit.

It is preferable that the shaft 110 be deformed and restored when passed through the dilator, and that it has enough deformability that the practitioner can manually bend it into a desired shape.

The tissue perforation device disclosed herein allows the user to feel the tip of the device contacting the perforation site, greatly improving operability and safety, making it useful in cardiac surgery and other procedures.

100 Perforation device 110 Shaft 110A Curved portion 110B Straight portion 111 Outer shaft 111C Deformable portion 112 Inner shaft 112A Inner shaft tip 112B Inner shaft base end 112a Opening 115 Ring-shaped portion 115A Step portion 130 Perforation head 150 Operation portion 152 Power supply connector 153 Electrical cable 155 Liquid connector 200 Sheath assembly 210 Dilator 211 Dilator connector 212 Dilator tapered portion 213 Dilator small diameter portion 214 Lumen 215 Step 216 Dilator curved portion 220 Outer sheath 221 Sheath body 222 Sheath curved portion 223 Sheath tapered portion 224 Hub 225 Valve body 226 Liquid line 227 Sheath port

Claims (3)

a hollow cylindrical shaft having a curved portion provided at the distal end side and a straight portion provided at the proximal end side, the shaft being delivered to an affected area through a lumen in the body ;
a drilling head formed at the tip of the shaft for denaturing and drilling biological tissue;
the shaft includes an outer shaft that constitutes a part of the straight portion and the curved portion , and an inner shaft that is inserted into the outer shaft so that a tip portion thereof protrudes from the outer shaft and is fixed so as not to move relative to the outer shaft ,
A body tissue perforation device, wherein the proximal end of the inner shaft extends to the straight portion. The body tissue perforation device according to claim 1, wherein the outer shaft has an easily deformable portion formed in at least a portion of the curved portion, the wall thickness in a first radial direction along the radius of curvature of the curved portion being thinner than the wall thickness in a second radial direction perpendicular to the first radial direction. The body tissue-perforating device according to claim 1 or 2, which is an RF needle.