Stent graft delivery device

The stent graft delivery device includes a shaft on which the stent graft is placed on the distal side; a sheath which is slidable outside of the shaft; a handle which is provided on the proximal side of the shaft and the sheath; and an operation unit which is provided with a switch mechanism. When a rotating member is rotated, while in a state of pressing a switch member of the switch mechanism inward, the sheath moves backward and the shaft moves forward using the handle as a reference.

TECHNICAL FIELD

The present invention relates to a stent graft delivery device which delivers a stent graft providing a metal skeleton (frame) in a tubular graft to a body cavity, and more specifically, to a stent graft delivery device for deploying a stent graft at a length different from the original length.

BACKGROUND DISCUSSION

In the related prior art, surgical operations using artificial blood vessels for treatments of an aortic aneurysm or aortic dissection have been performed, but a low invasive treatment using a stent graft has been widely performed in recent years (for example, see WO97/048350). A general stent graft is formed by suturing and fixing a skeleton (stent) in which a wire such as a nickel titanium alloy or stainless steel is formed in a Z shape or a ring shape to an inner surface or an outer surface of a tube (graft) which is formed of a cloth (fabric) woven by threads of a resin such as a polyester in a cylindrical shape, and is indwelled in a desired blood vessel by being deployed and expanded in a body cavity.

For example, in a case where a treatment for an aortic aneurysm is performed with a stent graft, it is required for both ends thereof to be indwelled in a normal blood vessel in the vicinity of a pathological blood vessel. Accordingly, a necessary minimum indwelling length required for a stent graft treatment becomes the length between normal blood vessels located in front and back of the pathological blood vessel. In general, the placement position or a necessary length of a stent graft is predicted from an X-ray contrast image or a CT image acquired before a surgery. But since it is difficult to predict the placement position or the necessary length, the predicted length does not always reach the necessary indwelling length and thus a new stent graft is required to be additionally inserted so that both of the ends thereof indwell in a blood vessel having a plurality of bent sections. Further, in a case where an aneurysm generated in a bent section of a blood vessel is treated with an indwelling stent graft, there is a possibility that the bent section in the blood vessel is distorted in a process of recovery and both of the ends of the indwelling stent graft fall out.

As a method for solving the above-described problem, it has been considered to use a stent graft which is longer than the necessary length for indwelling and to indwell the stent graft while it is being contracted in the length direction as needed. The stent graft is contracted and the entire length thereof is shortened by an operator pushing up the entire delivery device while gradually deploying the stent graft from the central side thereof by lowering a sheath accommodating the stent graft which is arranged on the outer surface of a shaft.

However, such a method depends on the expertise and/or technique of an operator, so there is a possibility that a graft is turned over or skeletons (frames) overlap each other when the degree of pushing up the delivery device is great, for example.

SUMMARY

The disclosure herein provides a stent graft delivery device capable of easily deploying a stent graft at a length different from the original length without depending on the technique of an operator.

An exemplary embodiment of a stent graft delivery device includes a stent graft; a shaft on which the stent graft is placed; a tubular sheath which is slidable in an axial direction with respect to the shaft and capable of accommodating the stent graft; a handle which is provided on a proximal side of the shaft and the sheath; an operation unit which is movably provided in the axial direction with respect to the shaft, in a position separated from the handle in the axial direction, and which drives at least the sheath from among the shaft and the sheath; and a switch mechanism which is provided in the operation unit, in which the shaft and the sheath are provided and which is movable in the axial direction using the handle as a reference. Due to the action of the switch mechanism, the operation unit may switch states between a first state in which only the sheath from among the shaft and the sheath is allowed to be moved in the axial direction with respect to the handle while being operated by the operation unit and a second state in which the shaft and the sheath are allowed to be moved in directions opposite to each other with respect to the handle while being operated by the operation unit due to the action of the switch mechanism.

According to the aforesaid exemplary configuration of the disclosure, only the sheath from among the shaft and the sheath is moved in the proximal direction with respect to the handle and thus the stent graft may be deployed at the original length in a living body lumen by operating the operation unit when in the first state as set by the switch mechanism. In contrast, the sheath is moved in the proximal direction with respect to the handle and the shaft is moved in the distal direction with respect to the handle, and thus the stent graft in the living body lumen may be deployed to be shorter than the original length by operating the operation unit when in the second state as set by the switch mechanism. In such a manner, since the first state and the second state may be switched between each other by the switch mechanism, the size of the stent graft to be contracted is easily adjusted and the stent graft may be indwelled in a blood vessel at an arbitrary (desired) length which is shorter than the original length, depending on the length or meandering degree of a blood vessel of a patient. Hence, when compared with the technique of shortening the entire length of the stent graft by pushing up the entire stent graft delivery device as in the prior art, the disclosure here provides a technique of easily shortening the entire length of the stent graft with less dependence on the expertise and/or technique of the operator.

In the aforesaid exemplary embodiment of the stent graft delivery device according to the disclosure, the operation unit includes a rotating member which is rotatable with respect to the shaft and the sheath and which is connected to the sheath, and a guide member which is connected in a rotatable manner with respect to the rotating member and which is not rotatable relative to the shaft, wherein the shaft and the sheath are not rotatable relative to one another. An end of a flexible linear member is wound around the rotating member, another end of the linear member is fixed to the handle, and the guide member may guide a middle portion of the linear member between a portion wound around the rotating member and a portion fixed by the handle.

According to the aforesaid exemplary configuration, the linear member is wound around the rotating member along with the rotation operation, so the operation unit is drawn toward the handle side, and thus the sheath may be reliably moved in the proximal direction.

Further, in the aforesaid stent graft delivery device, the rotating member includes an outer cylindrical portion and a bobbin portion which is provided in the outer cylindrical portion and which has the linear member wound around it, and the guide member may be arranged so as to cover the bobbin portion in the outer cylindrical portion.

In addition, according to the aforesaid exemplary embodiment, since the guide member is provided in the rotating member, the operation unit may be formed in a compact manner.

In the exemplary embodiment of the stent graft delivery device according to the disclosure, the guide member is provided with a guide hole in which one end is open at a site facing the bobbin portion in an inner peripheral portion of the guide member and another end is open on the proximal surface of the guide member such that the middle portion of the linear member may be slidably guided by the guide hole.

Thus, according to the aforesaid exemplary configuration, it is possible for the linear member to be appropriately guided from the handle side to bobbin portion side.

In the exemplary embodiment of the stent graft delivery device according to the disclosure, a first biasing member may be provided which biases the operation unit in a direction separating the operation unit from the handle.

According to the above configuration, since tension strength is applied to the linear member in a state in which a biasing force of the first biasing member is acted, the distance between the handle and the operation unit may be reliably held at the distance prescribed by the linear member.

Further, in the aforesaid stent graft delivery device, one end of the first biasing member may be attached to the proximal surface of the guide member and another end may be attached to the distal surface of the handle.

Hence, according to the aforesaid configuration, since the first biasing member is arranged between the guide member and the handle which are not rotatable relative to each other, the first biasing member is not twisted even when the rotating member is operated.

In the aforesaid stent graft delivery device, a spiral groove may be formed in the outer peripheral portion of the shaft, and the switch mechanism may include a switch member which is displaceable between a position engaged with the spiral groove and a position separated from the spiral groove.

According to the aforesaid configuration, a feed screw mechanism is formed by the switch member and the spiral groove and the sheath may be reliably moved in the axial direction with respect to the handle by operating the rotating member to be rotated in a state in which the switch member and the spiral groove are engaged with each other.

In the aforesaid stent graft delivery device, the switch mechanism includes a second biasing member which biases the switch member in a direction separating the switch member from the spiral groove, and the switch member may be engaged with the spiral groove when a pushing operation is performed on the switch member.

According to the aforesaid configuration, since the operation unit maintains the first state when the switch member is not pushed and the operation unit enters the second state only when the switch member is operated (pushed in), switching between the first state and the second state may be smoothly performed.

In the aforesaid stent graft delivery device, the shaft is provided with a slit-shaped or a groove-shaped guide unit which intersects the spiral groove and extends in the axial direction. A plurality of the switch members may be provided in the circumferential direction in the operation unit at intervals.

According to the aforesaid exemplary configuration, since another guide member is necessarily engaged with the spiral groove even when any one of the switch members is in the position to be inserted into the guide unit while the rotating member is operated to rotate in a state in which the switch member and the spiral groove are engaged with each other, the shaft may be smoothly moved forward by the rotation operation of the rotating member, so the operability thereof is excellent.

Further, in the aforesaid stent graft delivery device, relative displacement resistance between the handle and the shaft may be greater than friction resistance between the sheath and the stent graft.

According to the exemplary embodiment of the disclosure, it is possible to prevent the shaft from moving in the proximal direction together with the sheath when the sheath is allowed to be moved in the proximal direction with respect to the handle.

More particularly, in the aforesaid stent graft delivery device, an intermediate member may be included in which one end is fixed to the guide member and another end is slidably inserted into the handle, and a displacement restricting mechanism may be included which allows the intermediate member to be displaced in the proximal direction with respect to the handle and inhibits the intermediate member from being displaced in the distal direction with respect to the handle.

According to the aforesaid exemplary configuration, it is possible to prevent the sheath from moving in the distal direction with respect to the handle.

In the aforesaid exemplary stent graft delivery device, the displacement restricting mechanism may include a restriction release unit which releases displacement restriction with respect to the intermediate member.

According to the aforesaid configuration, it is possible for the sheath to move in the distal direction with respect to the handle as needed.

Further, according to an exemplary embodiment of the stent graft delivery device of the disclosure, the stent graft may be easily deployed at a length different from the original length without depending on the technique of an operator.

DETAILED DESCRIPTION

Hereinafter, a stent graft delivery device10according to the disclosure here will be described with reference to preferred exemplary embodiments and the accompanying drawings.

FIG. 1is a partially omitted perspective view illustrating the stent graft delivery device10(hereinafter, simply referred to as a “delivery device10”) according to an exemplary embodiment of the disclosure herein. InFIG. 1, for convenience of understanding, the middle portion (between the distal side portion and the proximal side portion) in the longitudinal direction of the long delivery device10is partially omitted.FIG. 2is a partially omitted longitudinal cross-sectional view illustrating the delivery device10.

The delivery device10is a medical device for treating a lesion portion by allowing a stent graft12placed and accommodated (mounted) on the distal side to reach the lesion portion (portion to be treated), such as an aortic aneurysm, through a blood vessel, and by deploying and indwelling the stent graft12. In addition, hereinafter, for description, the right side (a handle18side) of the delivery device10inFIG. 1is referred to as the “proximal (rear end)” side, and the left side (the stent graft12side) of the delivery device10is referred to as the “distal” side.

The delivery device10includes the stent graft12, a long shaft14on which the stent graft12is placed, a tubular sheath16which is slidable in the axial direction with respect to the shaft14and accommodates the stent graft12, a handle18which is provided on the proximal side of the shaft14and the sheath16, and an operation unit20which is provided in a position separated from the handle18in the axial direction.

The stent graft12which is delivered and indwelled in a living body has a self-expanding function. In general, a stent graft12having a configuration in which a stent12b(seeFIG. 6B) which is a metal skeleton (frame) for expansion is fixed on the inner surface or the outer surface of a tubular graft12a(seeFIG. 6B) can be used.

InFIG. 3, the stent graft12is in a state (contracted state) in which the stent graft is accommodated in a storage space formed by the sheath16and a mounting portion13provided in the shaft14and the stent graft12is folded (i.e., compressed) since the expansion thereof is restricted. The stent graft12is expanded and deployed by the self-expanding function when the sheath16moves backward with respect to the shaft14and the stent graft12accommodated inside of the storage space is released from the restriction by the sheath16.

The tubular graft12amay be formed of a cloth (fabric) woven into a tubular shape by threads of a resin such as polyester or a film of ePTFE (stretched polytetrafluoroethylene), for example. The stent12bmay include a plurality of skeletons (frames) defined by a wire formed of an alloy with superelasticity such as a Ti—Ni alloy or the like in a circular shape or a Z shape. The plurality of skeletons (frames) are arranged in the axial direction of the graft12aor a wire formed of an alloy with superelasticity or the like is knitted into a mesh shape.

As shown inFIG. 3, the shaft14is an elastic tubular member having flexibility formed by a guide wire lumen14a, into which a guide wire74(seeFIG. 6A) can be inserted, and penetrate over the entire length thereof. A tapered nose portion15(nose cone) is provided at the distal of the shaft14. A mounting portion13for placing (mounting) the stent graft12is provided in the vicinity of the distal portion of the shaft14, that is, at the proximal side of the nose portion15. The mounting portion13can position and hold the stent graft12in a diameter-reduced state by the sheath16and in the axial direction by a front wall13aforming steps on the distal side and a rear wall13bforming steps on the proximal side.

As shown inFIGS. 1 and 2, a spiral groove22is provided in a predetermined range of the outer peripheral portion on the proximal side of the shaft14. The spiral groove22is a recessed groove spirally extending over the predetermined range in the axial direction in the outer peripheral portion of the shaft14. In addition, a guide unit24intersecting the spiral groove22and extending in the axial direction is provided in the predetermined range of the outer peripheral portion on the proximal side of the shaft14. In the exemplary embodiment as illustrated, the guide unit24is formed in a slit shape communicating in and out of the shaft14in the radial direction, but a guide unit24having a groove shape (a recessed shape having a bottom portion) which extends in the axial direction in the outer peripheral portion of the shaft14may also be provided instead of the slit-shaped guide unit24.

The guide unit24in the exemplary embodiment reaches (opens on the proximal surface of the shaft14) the proximal portion of the shaft14, but the guide unit24may be extended to a further position on the distal side than on the proximal of the shaft14.

The sheath16includes a sheath main body25which is slidable in the axial direction of the shaft14on the outer side of the shaft14and a sheath hub26which is connected to the proximal portion of the sheath main body25and has a diameter greater than that of the sheath main body25. The sheath16is integrally displaceable in the axial direction with respect to the shaft14. The sheath main body25is a thin and elastic tubular member with flexibility which is slidably arranged in the axial direction on the outer surface side of the shaft14.

The sheath hub26is provided with a circular flange portion28which is projected outward in the radial direction on the proximal side. The flange portion28is engaged with a rotating member30of the operation unit20in a relatively rotatable manner around an axis, as described below.

As shown inFIG. 4, the sheath hub26is provided with an anti-rotation pin27(rotation preventing means) inhibiting relative rotation of the sheath16containing the sheath hub26with respect to the shaft14. In the exemplary embodiment, a plurality of the anti-rotation pins27are provided in the axial direction at spaced intervals, but it is enough to provide only one anti-rotation pin27. The respective anti-rotation pins27are held (fixed) by a holding hole26aprovided in the sheath hub26in a state in which one end portion of the anti-rotation pin27is projected into a hollow portion of the sheath hub26. The one end portion of the anti-rotation pin27projected in the hollow portion of the sheath hub26is thus engaged with the guide unit24provided on the shaft14. The sheath16containing the sheath hub26is rotatably movable in the axial direction with respect to the shaft14by the engagement between the anti-rotation pin27and the guide unit24, but the relative rotation about the axis with respect to the shaft14is inhibited.

In addition, the rotation preventing means inhibiting the relative rotation of the sheath16and the shaft14is not limited to the aforesaid anti-rotation pin27, and, for example, may have a configuration in which a projection is integrally provided on the inner periphery portion of the sheath hub26and engaged with the guide unit24.

A construction material of the shaft14and the sheath16is not particularly limited, and examples thereof may include a polymer material such as a polyolefin (for example, a polyethylene, a polypropylene, a polybutene, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, an ionomer, or a mixture of two or more kinds thereof), a polyvinyl chloride, a polyamide, a polyamide elastomer, a polyurethane, a polyurethane elastomer, a polyester, a polyester elastomer, a polyimide, or a fluorine resin; and a mixture thereof; and a multilayer tube with two or more kinds of the aforesaid polymer materials.

The handle18constituting the proximal portion of the delivery device10is a portion gripped by a user and a cylindrical member having a length and an outer diameter suitable for easy gripping. As shown inFIGS. 1 and 2, the handle18is provided with an insertion hole32into which the shaft14is slidably inserted and a guide hole33into which a rod70is slidably inserted, in parallel with each other in the axial direction. In the exemplary embodiment, both ends of the insertion hole32are open, but the proximal side may be closed depending on the length of the shaft14to be inserted. In the exemplary embodiment, both ends of the guide hole33are also open, but the proximal side may be closed depending on the length of the rod70to be inserted.

An anti-rotation pin35(rotation preventing means) which inhibits the relative rotation of the handle18and the shaft14is further provided on the handle18. In the exemplary embodiment, a plurality of the anti-rotation pins35are provided in the axial direction at spaced intervals, but only one anti-rotation pin35may be provided. The respective anti-rotation pins35are held (fixed) by a holding hole18aprovided on the handle18in a state in which one end portion of the anti-rotation pin is projected into the insertion hole32of the handle18. One end portion of the anti-rotation pin35projected into the insertion hole32is engaged with the guide unit24provided on the shaft14. The shaft14is relatively movable in the axial direction with respect to the handle18by the engagement between the anti-rotation pin35and the guide unit24, but the relative rotation around the axis with respect to the handle18is inhibited.

In addition, the anti-rotation means inhibiting the relative rotation of the handle18and the shaft14is not particularly limited to the aforesaid anti-rotation pin35, and, for example, may have a configuration in which a projection is integrally provided in the inner periphery portion of the handle18and engaged with the guide unit24.

The relative displacement resistance between the handle18and the shaft14is greater than the friction resistance between the sheath16and the stent graft12. Specifically, the relative displacement resistance between the handle18and the shaft14becomes greater than the friction resistance between the sheath16and the stent graft12by setting the thickness (outer diameter) of the anti-rotation pin35approximately the same as the width of the guide unit24provided on the handle18or greater than the width thereof. Due to this configuration, the shaft14can be prevented from moving in the proximal direction together with the sheath16while the sheath16is allowed to move in the proximal direction with respect to the handle18.

In regard to the shaft14and the sheath16, the shaft14is movably supported in the distal direction (distal direction) and the sheath16is movably supported in the proximal direction (proximal direction) from the initial position (position before starting to use) shown inFIG. 1using the position of the handle18as a reference.

In addition, the shaft14is arranged on the most proximal side in the movable range and the sheath16is arranged on the most distal side in the movable range using the position of the handle18as a reference at the initial position shown inFIG. 1. Further, in the delivery device10, the sheath main body25of the sheath16completely covers the mounting portion13of the shaft14and accommodates the stent graft12arranged in the mounting portion13by contracting the whole length thereof in the initial position.

The movable range of the sheath16with respect to the shaft14is set such that the most distal portion of the sheath16is positioned further on the proximal side than the rear wall13bof the mounting portion13provided on the shaft14and the stent graft12can be completely extracted when the sheath16is displaced to the most proximal side.

In the exemplary embodiment, the operation unit20is arranged to be displaceable in the axial direction with respect to the shaft14further on the distal side than the handle18. As shown inFIG. 4, the operation unit20includes the rotating member30which is relatively movable with respect to the shaft14and the sheath16and which is connected to the sheath16; a guide member36which is connected to the rotating member30in a relatively rotatable manner and which is not relatively rotatable with respect to the shaft14; and a switch mechanism38which is provided in the rotating member30, and which permits an operator (user) to perform a switching operation. At least the sheath16from among the shaft14and the sheath16is driven in the proximal direction by the operation of the operation unit20.

The operation unit20can switch states between a first state (non-interlocking state) in which only the sheath16from among the shaft14and the sheath16is allowed to be moved in the axial direction (basically proximal direction) with respect to the handle18while being operated by the operation unit20and a second state (interlocking state) in which the shaft14and the sheath16are allowed to be moved in directions opposite to each other with respect to the handle18while being operated by the operation unit20due to the action of the switch mechanism38.

The rotating member30includes an axial passage opening or hole42, into which the shaft14is slidably inserted; an annular concave portion44provided on the distal side of the rotating member30; an outer cylinder portion46provided on the proximal side of the rotating member30; and a hollow cylindrical bobbin portion48concentrically projecting in the proximal direction with the outer cylinder portion46in the outer cylinder portion46. The sheath hub26and the rotating member30are relatively rotatable around the axis and are not relatively movable in the axial direction due to the engagement of the flange portion28and the annular concave portion44.

An end of a linear member40is fixed to and wound around the bobbin portion48. The linear member40is a member stretched between the handle18and the operation unit20with flexibility. One end thereof is wound around the rotating member30and another end is fixed to the handle18. A portion of the linear member40between the guide member36and the handle18extends in parallel with the shaft14. The linear member40is formed of metal or resin wire, or threads, for example.

The guide member36is a hollow cylindrical member arranged so as to cover the bobbin portion48in the outer cylinder portion46. An annular convex portion50projecting inwardly is provided on the distal inner peripheral portion of the guide member36. The rotating member30and the guide member36are relatively rotatable around the axis and are not relatively movable in the axial direction due to engagement of the annular convex portion50of the guide member36and the annular concave portion52provided on the distal side outer peripheral portion of the bobbin portion48.

The guide member36is provided with an anti-rotation pin54(rotation preventing means) inhibiting the relative rotation of the guide member36and the shaft14. In the exemplary embodiment, a plurality of the anti-rotation pins54are provided in the axial direction at spaced intervals, but only one anti-rotation pin54may be provided. The respective anti-rotation pins54are held (fixed) by a holding hole55provided in the guide member36in a state in which one end portion projects to a penetrating hole37of the guide member36. One end portion of the anti-rotation pin54projected into the penetrating hole37is engaged with the guide unit24provided on the shaft14. The operation unit20including the guide member36is relatively movable in the axial direction with respect to the shaft14, but the relative rotation around the axis is inhibited with respect to the shaft14by engaging the anti-rotation pin54with the guide unit24.

In addition, the anti-rotation means which inhibits the relative rotation of the guide member36and the shaft14is not particularly limited to the aforesaid anti-rotation pin54, and, for example, the anti-rotation means may have a configuration in which a projection is integrally provided on the inner peripheral portion of the guide member36and the projection is engaged with the guide unit24.

The guide member36guides a portion of the linear member40between a portion wound around the rotating member30and a portion fixed to the handle18. Specifically, the guide member36is provided with a guide hole58in which one end is open at a site facing the bobbin portion48in the inner peripheral portion of the guide member36and another end is open on the proximal surface of the guide member36. A portion of the linear member40between a portion wound around the rotating member30and a portion fixed to the handle18is slidably guided by the guide hole58.

In the exemplary embodiment, as shown inFIG. 4, the switch mechanism38includes a switch member60which is displaceable to a position engaged with the spiral groove22provided on the shaft14and a position separated from the spiral groove22, and an elastic member62(second biasing member) biasing the switch member60in a direction separating the switch member60from the spiral groove22. The switch member60includes a pin-shaped (rod-shaped) flange portion61projecting outwardly in the longitudinal direction. The rotating member30is provided with a hole portion64formed between the inner peripheral portion and the outer peripheral portion in the radial direction. A diameter expanding unit65is provided on the middle portion of the rotating member30in the radial direction of the hole portion64. The flange portion61of the switch member60is movable in the radial direction of the rotating member30in the diameter expanding unit65.

The elastic member62is arranged in the diameter expanding unit65, one end thereof is brought into contact with the flange portion61, and the switch member60is constantly and elastically pushed outwardly in the radial direction. Accordingly, when the switch member60is pushed inward with a force greater than the elastic force of the elastic member62from the outside of the rotating member30, the switch member60moves inward in the radial direction as shown inFIG. 5. When the pushing with respect to the switch member60is released, the switch member60is returned to a position shown inFIG. 4due to the elastic force of the elastic member62. The elastic member62in the exemplary embodiment is a coiled compression spring. When the rotating member30rotates around the axis with respect to the shaft14, the switch member60also rotates around the axis of the shaft14integrally with the rotating member30.

As shown inFIG. 4, one end (outer end) of the switch member60projects from the outer peripheral portion of the rotating member30and another end (inner end) of the switch member60is separated from the spiral groove22provided on the shaft14in a state of not pushing the switch member60from the outside. In other words, the switch member60and the spiral groove22are in the non-engaged state. When the rotating member30is operated to rotate in a predetermined direction with respect to the handle18in this non-engaged state, the distance between the handle18and the operation unit20containing the rotating member30becomes smaller and the sheath16connected to the operation unit20is moved in the proximal direction with respect to the handle18by the linear member40being wound around the bobbin portion48.

In contrast, as shown inFIG. 5, the another end (inner end) of the switch member60is engaged with the spiral groove22provided on the shaft14in a state in which the switch member60is pushed from the outside and displaced inward (inward in the radial direction). The switch member60and the spiral groove22function as a feed screw mechanism which allows the shaft14to be moved in the axial direction with respect to the operation unit20by engaging the switch member60with the spiral groove22. Consequently, when the switch member60and the spiral groove22are in an engaged state and the rotating member30is operated to rotate in the predetermined direction with respect to the handle18, the sheath16moves in the proximal direction with respect to the handle18and the shaft14moves in the distal direction with respect to the handle18.

In the exemplary embodiment, the switch mechanism38includes multiple pairs of the switch member60and the elastic member62in the circumferential direction in the operation unit20at spaced intervals (in the example of the figure, two pairs in the opposite position using the axial line of the rotating member30as a reference). According to this configuration, as shown inFIG. 5, when one switch member60is in a position to be inserted into the guide unit24of the shaft14, another switch member60is necessarily engaged with the spiral groove22when all the switch members60are pushed inward.

In the exemplary embodiment, as shown inFIGS. 1 and 2, an elastic member68(first biasing member) which biases the operation unit20in a direction separating the operation unit20from the handle18is provided between the handle18and the operation unit20. The elastic member68is formed of a coiled compression spring as shown in the example of the figure, and is arranged on the outer side of the shaft14between the operation unit20and the handle18. More specifically, one end of the elastic member68is brought into contact with the proximal surface of the guide member36and another end is brought into contact with the distal surface of the handle18. The rotating member30is rotatable with respect to the shaft14and the handle18, but the guide member36does not rotate with respect to the shaft14. Therefore, even when the rotating member30is operated to rotate, the elastic member68arranged in a state of being interposed between the guide member36and the handle18is not twisted. Alternatively, the elastic member68may not be present.

In the exemplary embodiment, the delivery device10further includes the rod70(intermediate member) extending along with the shaft14. The distal side of the rod70is fixed to the guide member36and the proximal side thereof is slidably inserted into the guide hole33provided on the handle18. Such a rod70functions as a rotation preventing means inhibiting the relative rotation of the guide unit24and the handle18. Since the rod70is slidable in the axial direction in the guide hole33, the handle18and the guide member36are relatively displaceable in the axial direction in a state in which the relative rotation thereof is inhibited by the rod70. In addition, since the guide member36is prevented from relatively rotating with the shaft14due to the engagement action between the anti-rotation pin35and the guide unit24, the rod70may not necessarily be provided. Alternatively, since the relative rotation of the shaft14and the guide member36is inhibited by the rod70through the handle18, the anti-rotation pin35may not necessarily be provided when the rod70is provided.

The delivery device10according to the exemplary embodiment is basically formed as described above, and the action and the effects thereof will be described below.

In regard to the delivery device10formed as described above, an action in which, without moving the shaft14in the distal direction with respect to the handle18, the sheath16is allowed to be moved in the proximal direction (moved backward) with respect to the handle18, and the stent graft12accommodated on the distal side in a diameter-reduced state is deployed and indwelled in a body cavity at the original length will be described. That is, a normal operation in which the stent graft12is deployed at the length according to the designed specification and indwelled in a blood vessel or the like, will be described. Further, the normal operation below will be mainly described with reference toFIGS. 6A and 6Band also appropriately described with reference to other figures (FIG. 1or the like).

When the normal operation is performed, firstly, the mode of a lesion portion such as an aneurysm generated in an aorta or the like is specified by an intravascular contrast method or an intravascular ultrasound diagnosis method. Next, as shown inFIG. 6A, the guide wire74is introduced by being advanced into a blood vessel72from a thigh portion or the like by, for example, a seldinger or other known method. The guide wire74is inserted into the proximal side from the distal side of the guide wire lumen14aof the shaft14(seeFIG. 2), and the shaft14and the sheath16are inserted into an aorta. Moreover, under the X-ray contrast using an X-ray opaque marker (not illustrated) provided on the distal side of the shaft14and the sheath16, the stent graft12which is accommodated on the distal side of the sheath16is delivered to a target position.

The state of the delivery device10shown inFIG. 6Aenters the initial state in which the sheath16is positioned on the most distal side in the movable range with respect to the handle18(seeFIG. 1), and the stent graft12is completely accommodated on the distal side of the sheath main body25. In a state in which the switch member60is not operated from the initial state, that is, in a state in which the switch member60is not pushed inward (seeFIG. 4), the operation unit20containing the rotating member30is moved toward the handle18side by winding the linear member40around the bobbin portion48when the rotating member30is gripped and is allowed to rotate in the predetermined direction around the axis with respect to the handle18and the shaft14. As shown inFIG. 6B, the sheath16connected to the rotating member30is moved in the proximal direction in this way.

At this time, since the relative movement in the axial direction between the handle18and the shaft14is restricted to a certain extent by an engaging force (friction resistance) between the anti-rotation pin35provided on the handle18and the guide unit24provided on the shaft14, the shaft14is not displaced in the proximal direction with respect to the handle18together with the sheath16due to the friction resistance between the sheath16and the stent graft12when the sheath16is moved in the proximal direction.

In the case of the exemplary embodiment, since the elastic member68(seeFIG. 1) biasing the operation unit20in a direction separating the operation unit20from the handle18is provided, the tension strength is applied to the linear member40by the elastic force of the elastic member68. Therefore, the distance between the handle18and the operation unit20is reliably held at the distance prescribed by the linear member40.

Further, since the sheath hub26is rotatably engaged with the rotating member30and the relative rotation around the axis with respect to the shaft14is inhibited, the sheath16does not rotate along with the rotation operation with respect to the rotating member30.

With the switch member60being elastically biased outwardly in the radial direction by the elastic member62, the switch member60is held in a position separated from the spiral groove22as long as an operator does not operate the switch member60by pushing inward. Accordingly, using the handle18as a reference, an operation for moving the sheath16in the proximal direction can be reliably performed without moving the shaft14in the distal direction.

The stent graft12which is restricted from expanding (deploying) in the main body of the sheath16is deployed by the self-expansion function in the blood vessel72by the release of the restriction in the process of the shaft14being moved in the proximal direction with respect to the sheath16. Further, when the distal end of the sheath16(sheath main body25) reaches a position further on the proximal side than the proximal end of the stent graft12, the stent graft12enters a complete deploying state over the entire length thereof.FIG. 6Billustrates the complete deploying state of the stent graft12. The stent graft12can be indwelled in the blood vessel72at the original length L1by the above-described operation.

Next, in regard to the delivery device10, an action in which the shaft14is moved (advanced) in the distal direction with respect to the handle18at the same time that the sheath16is moved (retreated) in the proximal direction with respect to the handle18, and the stent graft12accommodated on the distal side in the diameter-reduced state is indwelled and deployed to be shorter than the original length L1in a body cavity will be described. That is, a shortening operation in which the stent graft12is deployed at a length shorter than the designed specification and indwelled in a blood vessel or the like will be described. Further, the shortening operation below will be mainly described with reference toFIGS. 7A and 7Band also appropriately described with reference to other figures (FIG. 1or the like).

The shortening operation is performed when, for example, the stent graft12with a specification longer than a predicted length is deployed and indwelled while being contracted because a length necessary for indwelling cannot be precisely predicted with an X-ray contrast image or a CT image acquired before surgery due to a blood vessel having a plurality of bent sections.

Firstly, as shown inFIG. 7A, in the same manner as in the normal operation, the shaft14and the sheath16are inserted into an aorta and are delivered to a target position which is the distal side (position accommodating the stent graft12) of the shaft14and the sheath16in a state in which the guide wire74is advanced. Further, the switch member60of the switch mechanism38is operated to be pushed inward from the outside of the rotating member30and an inward end of the switch member60is inserted (interlocked) into the spiral groove22(seeFIG. 5). That is, the switch member60and the spiral groove22are in an engaged state.

Subsequently, the rotating member30is gripped and rotated in the predetermined direction while the engaged state between the switch member60and the spiral groove22is maintained. In this way, the operation unit20containing the rotating member30is moved to the handle18side by winding the linear member40around the bobbin portion48of the rotating member30, and the shaft14moves in the distal direction with respect to the operation unit20by the action of the feed screw mechanism formed by engaging the switch member60with the spiral groove22.

At this time, the stent graft12is deployed by moving the sheath16in the proximal direction at the same time that the stent graft12accommodated in the sheath16is extracted by the shaft14moving in the distal direction. As a result, a length by which the stent graft12is extracted from the sheath16is longer than a length by which the sheath16is moved in the proximal direction, and the deploying and indwelling are completed with a length L2shorter than the original length L1(seeFIG. 6B) in a body cavity as shown inFIG. 7B.

According to the delivery device10as described above, the entire length of the stent graft12can be simply and reliably shortened by moving the shaft14in the distal direction with respect to the handle18in a state of holding the position of the handle18when the sheath16is moved in the proximal direction with respect to the handle18to expand and deploy the stent graft12. Accordingly, a technique of easily shortening the entire length of the stent graft12with less dependence on the expertise and/or technique of the operator when compared with the technique of shortening the entire length of the stent graft12by pushing up the entire delivery device10as in the related prior art can be performed.

In the case of the exemplary embodiment, the sheath16is moved in the proximal direction with respect to the handle18at the same time that the shaft14is automatically moved in the distal direction by the action of the feed screw mechanism formed by the switch member60and the spiral groove22along with the operation for rotating the rotating member30in the predetermined direction in a state of pushing the switch member60inward. Therefore, the technique for shortening the stent graft12while expanding it can be simply and reliably performed without depending on the operator's skill.

In the case of the exemplary embodiment, since the linear member40is wound around the rotating member30along with the operation for rotating the rotating member30and thus the operation unit20is drawn into the handle18side, the sheath16can be reliably moved in the proximal direction. In addition, since the guide member36is provided in the rotating member30, the operation unit20can be formed in a compact manner.

Because the amount of movement of the shaft14with respect to the amount of movement of the sheath16is determined by the outer diameter of the bobbin portion48and the pitch of the spiral groove22when the shaft14is operated to advance while the sheath16is retreated using the handle18as a reference, the amount of shaft14movement to the amount of sheath16movement can be fixed to an arbitrarily set ratio. Consequently, in the stent graft12, the possibility that the stents12boverlap each other or that the graft12ais turned over can be reliably prevented.

In the exemplary embodiment, the operation unit20can switch states between (1) the first state (non-interlocking state) in which the sheath16is moved in the proximal direction with respect to the handle18without moving the shaft14in the distal direction with respect to the handle18when the operation unit20is operated and (2) the second state (interlocking state) in which the sheath16is moved in the proximal direction with respect to the handle18and the shaft14is moved in the distal direction with respect to the handle18when the operation unit20is operated by operating the switch mechanism38. Accordingly, the size of the stent graft12to be contracted is easily adjusted and the stent graft12can be indwelled in a blood vessel at an arbitrary (desired) length which is shorter than the original length, depending on the length or meandering degree of a blood vessel of a patient.

Further, in the exemplary embodiment, since the switch mechanism38includes the elastic member62which biases the switch member60outwardly in the radial direction of the rotating member30, the operation unit20maintains the first state when the switch member60is not pushed in and the operation unit20enters the second state only when the switch member60is operated to be pushed in. Therefore, the switch mechanism can be smoothly and reliably switched between the first state and the second state.

In addition, by providing a plurality of the switch members60in the circumferential direction in the operation unit20at spaced intervals, another guide member36is necessarily engaged with the spiral groove22when any one of the switch members60is in the position to be inserted into the guide unit24while the rotating member30is operated to rotate in a state in which the switch member60and the spiral groove22are engaged with each other. Therefore, the shaft14may be smoothly moved forward by the rotation operation of the rotating member30and the operability thereof is excellent.

As shown inFIG. 8, the delivery device10may include a ratchet mechanism80(displacement restricting mechanism) which allows the rod70to be displaced in the proximal direction with respect to the handle18and which is capable of inhibiting the rod70from being displaced in the distal direction with respect to the handle18.

The ratchet mechanism80includes a ratchet tooth82which is provided in the axial direction on the outer peripheral portion of the rod70; a ratchet claw member84which is capable of meshing with the ratchet tooth82; an elastic member86(for example, a spring member) which elastically biases the ratchet claw member84in a direction of pushing the ratchet claw member84to the ratchet tooth82; and a restriction release unit88which releases the engagement between the ratchet tooth82and the ratchet claw member84.

The ratchet tooth82is formed of a vertical surface82awhich is vertical with respect to the axis line of the shaft14and an inclined surface82binclining outwardly toward in the distal direction of the shaft14. A claw portion85which can be engaged with the ratchet tooth82is provided on one end of the ratchet claw member84, and the intermediate portion in the longitudinal direction is rotatably supported by an axis portion90. In the elastic member86, one end is attached to a wall in the handle18and another end is attached to the ratchet claw member84, and the ratchet claw member84is pushed toward the shaft14side.

The restriction release unit88is movably provided in the radial direction of the handle18in a state of penetrating the wall portion of the handle18. One end of the restriction release unit88projects to the outside of the handle18and another end is attached to another end side (opposite side of the claw portion85using the axis portion90as a reference) of the ratchet claw member84. A flange portion89which bulges outward is provided in the intermediate portion in the longitudinal direction of the restriction release unit88, and the restriction release unit88is prevented from escaping from the handle18by the flange portion89caught by the inner wall of the handle18.

In the ratchet mechanism80configured as described above, since the ratchet claw member84rotates in a direction in which the claw portion85moves away from the shaft14due to the taper action of the inclined surface82band the claw portion85climbs over the ratchet tooth82, the rod70is allowed to move in the proximal direction with respect to the handle18. Meanwhile, since the vertical surface82aof the ratchet tooth82is engaged with the claw portion85of the ratchet claw member84under the elastic biasing action with respect to the ratchet claw member84of the elastic member86, the rod70is inhibited from moving in the distal direction with respect to the handle18.

In an embodiment where the ratchet mechanism80is not provided, when a force is applied to the operation unit20in a direction separating the same from the handle18in the operation of the delivery device10, by the fact that the rotating member30rotates in a direction opposite to the direction when the sheath16is moved in the proximal direction and the linear member40wound around the bobbin portion48is extracted through the guide hole58, there is a possibility that the sheath16may move in the distal direction with respect to the handle18. In contrast, when the ratchet mechanism80is provided, the rod70is allowed to be displaced in the proximal direction with respect to the handle18, but the rod70is inhibited from being displaced in the distal direction with respect to the handle18, so it is possible to prevent the sheath16from unintentionally moving in the distal direction with respect to the handle18.

When the restriction release unit88is operated to be pushed inward, the ratchet claw member84rotates in a direction in which the claw portion85moves away from the ratchet tooth82by the restriction release unit88and the engagement between the ratchet claw member84and the ratchet tooth82is released. That is, movement restriction, due to the ratchet mechanism80, in the distal direction with respect to the rod70is released. The sheath16is movable in the distal direction when the rod70is movable in the distal direction with respect to the handle18. In this way, since the movement restriction with respect to the rod70can be simply and rapidly released by operating the restriction release unit88to be pushed, the sheath16can be moved in the distal direction with respect to the handle18as needed.

The disclosure herein has been described with reference to the preferred exemplary embodiments, but the present invention is not limited thereto, and various modifications are obviously possible within the range not departing from the scope of the present invention.

The detailed description above describes a stent graft delivery device disclosed by way of example. The invention is not limited, however, to the precise exemplary embodiments and variations described. Various changes, modifications and equivalents can effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.