Patent Description:
The use of catheter delivery systems for positioning and deploying therapeutic devices, such as dilation balloons, stents and embolic coils, in the vasculature of the human body has become a standard procedure for treating endovascular diseases. It has been found that such devices are particularly useful in treating areas where traditional operational procedures are impossible or pose a great risk to the patient, for example in the treatment of aneurysms in cranial blood vessels. Due to the delicate tissue surrounding cranial blood vessels, e.g. brain tissue, it can be difficult and often risky to perform surgical procedures to treat defects of the cranial blood vessels. Advancements in catheter-based implant delivery systems have provided an alternative treatment in such cases. Some of the advantages of catheter delivery systems are that they provide methods for treating blood vessels by an approach that has been found to reduce the risk of trauma to the surrounding tissue, and they also allow for treatment of blood vessels that in the past would have been considered inoperable.

Typically, these procedures involve inserting a delivery catheter into the vasculature of a patient and guiding it through the vasculature to a predetermined delivery site. The delivery system can include an engagement/deployment system to releasably attach a vascular occlusion device, stent, or other intravascular treatment device to a delivery member (e.g. micro-catheter). The delivery member with the treatment device attached thereto can be pushed through the delivery catheter to the delivery site. Example delivery members and engagement/deployment systems are described in <CIT> and <CIT>.

Some of the challenges that have been associated with properly executing such treatment procedures include ensuring the delivery member and engagement system remain in a stable position throughout a treatment. For example, in some aneurysm treatment applications, as the aneurysm becomes increasingly packed with embolic material, the delivery member can tend to shift due to increasing pushback from the embolic material being implanted. If the delivery member shifts during treatment, a physician may not be able to accurately control placement of embolic material and may choose to cease packing the aneurysm. In such an example, the aneurysm may not be sufficiently packed, which can lead to recanalization. Further, excessive movement or stretching of the delivery member and/or engagement system thereon can result in premature detachment of an embolic coil or other treatment device.

Document <CIT> discloses a detachment system for delivering an implantable medical device to a target location of a body vessel that has a generally hollow distal tube. The distal tube includes a proximal end, a distal end, and a compressible portion of the tube itself, between the proximal and distal ends which is axially movable from a compressed to an elongated condition. A generally hollow proximal tube has a proximal end and a distal end. A coupling joins the proximal and distal tubes. An engagement system engages and deploys the implantable medical device engaged at the distal end of the distal tube. The engagement system moves the compressible portion to the compressed condition when engaging the implantable medical device, and deploys the implantable medical device and releases the compressible portion to the elongated condition.

Document <CIT> discloses a coil assembly for use in medical devices. It discloses an outer coil disposed about an inner coil. The outer coil windings are affixed to the inner coil windings with a plurality of affixation point. An outer member, such as an outer tubular member can be disposed about at least a portion of the outer. The outer member can be formed from a variety of materials including metals or polymeric materials.

Document <CIT> is a prior art document pursuant to Article <NUM>(<NUM>) EPC and discloses an embolic implant that can include an embolic coil, a detachment feature, and a stretch resistant fiber. The detachment feature can be affixed to the embolic coil at the proximal end of the embolic coil. The stretch resistant fiber can be engaged to the detachment feature, extend through the lumen of the embolic coil, and can be affixed to the embolic coil at the distal end of the embolic coil. Configured thusly, the stretch resistant fiber can be effective to limit separation of windings of the embolic coil as the embolic coil is reshaped. The detachment feature can have a singular opening that is sized to receive a loop wire of a mechanical delivery system and through which the stretch resistant fiber passes.

There is therefore a need for improved methods, devices, and systems to provide an implant delivery member and implant engagement system with increased stability.

The invention is defined by claims <NUM> and <NUM>. It is an object of the present invention to provide systems, devices, and methods to meet the above-stated needs. Generally, it is an object of the present invention to provide a delivery system for delivering and deploying an implantable medical device that includes a delivery member having a flexible distal portion.

Stiffness of the distal portion of the delivery member can cause the microcatheter used for delivery of the embolic material to pull back from the aneurysm as embolic material is pushed into a densely packed aneurysm. If the microcatheter pulls back while advancing the embolic material, the microcatheter may come out of the aneurysm or otherwise move out of position. In such circumstances, the physician may lose control of the embolic coil, may not be able to accurately control placement of embolic material, and/or may not be able to complete treatment.

Flexibility can be provided by incorporating a length of wound coil along the distal portion of the delivery member. The wound coil can be protected by a flexible polymer sleeve positioned around the outside of the coil. The wound coil can be inhibited from elongating by a stretch resistant loop wire positioned to extend through the wound coil and releasably secure the implant.

An example delivery system can be configured to deliver an implantable medical device to a target location of a body vessel. The example delivery system can include a proximal hypotube, a flexible coil extending distally from the proximal hypotube, a compressible distal hypotube extending distally from the flexible coil, a sleeve extending along the flexible coil, and a loop wire. The loop wire can be effective to inhibit longitudinal elongation of the flexible coil. The sleeve can be effective to inhibit radial expansion of the flexible coil.

The delivery system can further include a pull wire, that in conjunction with the loop wire, is effective to secure the implant to the delivery system. The loop wire and the pull wire can be movable to release the implant from the delivery system. The delivery system can include a lumen extending through the proximal hypotube, flexible coil, a distal hypotube. The loop wire and the pull wire can be positioned within the lumen. The loop wire can have a first end affixed to the proximal hypotube and a loop opening positioned to secure the implant to the delivery system. The loop opening can be positioned at the distal end of the compressible distal hypotube.

When the implant is secured to the delivery system, the loop opening can extend through an opening in the implant and the pull wire can extend through the loop opening. So configured, the loop wire can be under tension, inhibiting elongation of the flexible coil. The compressible distal portion can be compressed when the implant is secured to the delivery system such that the compressed distal portion provides tension to the loop wire and the loop wire inhibits elongation of the compressed distal portion.

The pull wire can be proximally retractable to exit the loop opening. The loop opening can be movable to exit the implant opening when the loop opening is unobstructed by the pull wire.

The sleeve can be effective to inhibit radial expansion of the flexible coil. The sleeve can cover most or all of the outer surface of the flexible coil.

The flexible coil can be more flexible than the proximal hypotube. The flexible coil can also be more flexible than the compressible distal hypotube. The flexible coil can include one or more non-radiopaque sections and one or more radiopaque sections. The flexible coil can include two non-radiopaque sections separated by a radiopaque section such that the non-radiopaque sections extend from a proximal and distal end of the flexible coil and the radiopaque section is between the non-radiopaque sections. The flexible coil can be constructed from a wound wire. The wound wire can define a portion of the lumen of the delivery system. The wire strand that is wound can have a strand diameter measuring from about <NUM> thousandths of an inch to about <NUM> thousandths of an inch, or about <NUM> micrometers to about <NUM> micrometers. The strand of the wire can have a substantially circular cross section.

The length of a distal portion of the delivery system can be measured from the distal end of the compressible distal hypotube to the proximal end of the flexible coil. The length of the distal portion can measure from about <NUM> to about <NUM>, or more specifically about <NUM>.

The compressible distal hypotube can include a spiral cut. The compressible distal hypotube can be compressed due to tension in the loop wire when the implant is secured to the delivery system. The compressible distal hypotube can be movable to decompress upon movement of the loop wire and the pull wire to release the implant.

An example method can include step for designing or constructing a delivery member such as the example above. The method can include connecting a distal end of a proximal tube to a proximal end of the coiled wire, connecting a distal end of the coiled wire to a proximal end of a compressible distal tube, positioning a sleeve along a majority of the length of the coiled wire, inhibiting radial expansion of the coiled wire with the sleeve, affixing a loop wire to the proximal tube, positioning a loop opening in the loop wire at a distal end of the distal tube while the loop wire is affixed to the proximal tube such that the loop wire is extended through the coiled wire, and inhibiting longitudinal elongation of the coiled wire with the loop wire. The proximal tube, coiled wire, and compressible tube can be connected to form a lumen that extends through the three parts.

The distal tube can be compressed and, while the loop wire is affixed to the proximal tube and the distal tube is compressed, the loop opening can be positioned at the distal end of the distal tube and the loop wire can be used to secure the implant to the delivery tube. Once the implant is secured, tension in the loop wire can maintain compression of the distal tube and inhibit longitudinal expansion of the coiled wire. The sleeve can inhibit radial expansion of the tube.

An intravascular implant can be secured to the delivery tube by extending a pull wire through the lumen of the three parts, extending the loop opening through a locking portion of the intravascular implant, and extending a distal end of the pull wire through the loop opening. The implant can be secured such that during treatment, the implant can be released from the distal tube by retracting the distal end of the pull wire from the loop opening and retracting the loop opening from the locking portion of the intravascular implant.

The coiled wire and the sleeve can be selected such that when the sleeve is in position along most of the length of the coiled wire, the combination of the sleeve and coiled wire is more flexible than both the proximal hypotube and the compressible distal tube.

The coiled wire can be selected such that the coiled wire includes a wire wound to define a portion of the lumen extending through the coiled wire. The wire which is wound to form the lumen can itself have a cross-sectional diameter measuring from about <NUM> thousandths of an inch to about <NUM> thousandths of an inch, or about <NUM> micrometers to about <NUM> micrometers.

A radiopaque coiled section can be positioned in the coiled wire.

The coiled wire and the compressible distal tube can be sized to have a length measurable from the distal end of the distal tube to the proximal end of the coiled wire such that the length measures from about <NUM> to about <NUM>, or more specifically about <NUM>.

The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.

A key success factor in intravascular treatment such as aneurysm treatments is for the delivery member (e.g. microcatheter) to remain stable during the deployment of an implant or other medical treatment device. During an intravascular treatment, lack of flexibility of a distal portion of a treatment device delivery member can cause the delivery member to pull back from the treatment site or otherwise move out of position while the implant is being placed in an aneurysm or other treatment site. A delivery member and engagement system having a more flexible distal portion can therefore provide a stable system for delivering medical devices in neurovascular anatomy in addition to other applications facing a similar challenge. Flexible structures, however can tend deform, extend, or expand when navigating tortuous anatomy. Deformation of the delivery member can inhibit the delivery member's ability to navigate to a treatment site and/or effectively deploy the medical device. Elongation of the delivery member can result in premature deployment of the medical device.

An object of the present invention is to provide a delivery member having a highly flexible distal portion that is stretch resistant and structurally stable throughout delivery and deployment of a medical treatment device. For ease of discussion, medical treatment devices are generally referred to herein as an "implant" although, as will be appreciated and understood by a person of ordinary skill in the art, aspects of the present invention can be applied to deliver and deploy medical treatment devices that are not left implanted.

According to the present disclosure, in some examples, a delivery member can include a proximal elongated delivery hypotube, a coiled assembly attached to the distal end of the proximal hypotube, and a laser cut spiraled segment attached distally to the coiled assembly. The coiled assembly can be designed to be highly flexible. The coiled assembly can include a coiled wire covered by an outer sleeve. The coiled wire can include one or more radiopaque coiled segments concentrically welded near a distal section of the coiled assembly.

The proximal hypotube can extend a majority of the length of the delivery member such that the coiled assembly and the distal laser cut spiraled hypotube extend over about <NUM> to about <NUM>, or more specifically about <NUM>, from the distal end of the delivery member. The distal spiraled hypotube can be axially compressed in a similar manner to a spring.

The assembly of tubes and coiled assembly can contain within its lumen a pull wire and a locking member in the form of a loop wire that together are positioned to secure an implant to the delivery member. The implant can be detached by displacing the pull wire proximally until the pull wire clears the locking member allowing the implant to be released from the delivery member.

The loop wire can be constructed of a stretch resistant fiber having two ends. One leg of the loop wire can be connected at the proximal end of the laser cut spiraled distal hypotube while the other leg can be connected in the proximal direction in relation to the proximal end of the coiled assembly. The leg stretching proximal to the coiled assembly and extending to the proximal end of the spiral cut hypotube can serve the function of a stretch resistant member to prevent the very flexible coiled assembly from stretching as the delivery member is manipulated during delivery of the implant which could result in premature detachment of the implant. Alternatively, both legs of the loop wire can be attached proximal to the proximal end of the coiled assembly. In some applications two legs extended through the coiled assembly can provide improved stretch resistant of the coiled assembly compared to a single leg extending through the coiled assembly.

In some applications, for instance if the implant is an embolic coil, it can be desirable to minimize insertion of the pull wire into the implant in order to minimize stiffening of the proximal end of the implant. However, it can also be desirable to extend the pull wire through the loop wire with sufficient length to minimize the likelihood that the pull wire disengages from the loop wire due to the pull wire shifting and/or the delivery member deforming, thereby prematurely releasing the implant. In some applications, the stretch resistance of the loop wire can inhibit elongation of the delivery member, thereby reducing the likelihood of prematurely releasing the implant and/or allowing the pull wire to be positioned with a shorter length into the implant thereby increasing flexibility at the proximal end of the implant.

Turning to the figures, as illustrated in <FIG>, and <FIG> an example delivery member 10a, 10b can include a proximal tube <NUM>, a coiled section 200a, 200b, a distal tube <NUM>, a sleeve <NUM> surrounding the coiled section, and a loop wire 400a, 400b extending through the coiled section 200a, 200b. The delivery member 10a, 10b can have a lumen <NUM> therethrough extending through the proximal tube <NUM>, coiled section 200a, 200b, distal tube <NUM>. In other words, the proximal tube <NUM> can have a lumen <NUM> therethrough, the coiled section 200a, 200b can have a lumen <NUM> therethrough, the distal tube <NUM> can have a lumen <NUM> therethrough, and the lumens <NUM>, <NUM>, <NUM> can be contiguous to form the lumen <NUM> through the delivery member 10a, 10b. The proximal tube <NUM> can have a distal end <NUM> connected to a proximal end <NUM> of the coiled section 200a, 200b, and a distal end <NUM> of the coiled section 200a, 200b can be connected to a proximal end <NUM> of the distal tube <NUM>.

When the delivery member 10a, 10b is assembled, the coiled section 200a, 200b and sleeve <NUM> can be more flexible than the distal hypotube and the proximal hypotube. One way to measure flexibility is to perform a three-point bend test wherein a portion of the delivery member 10a, 10b is held fixed at two end points, a force is applied perpendicularly to the member 10a, 10b centrally between the points, and flexibility is quantified by the length of deflection of the delivery member 10a, 10b caused by the force. When measured this way, in some examples, the coiled section 200a, 200b and sleeve <NUM> can be about <NUM> times more flexible than the distal hypotube and about <NUM> times more flexible than the proximal hypotube <NUM>. In other words, when the three-point test is performed identically on the three sections <NUM>, 200a, 200a, <NUM>, the coiled section can deflect over a length that is about <NUM> time the deflection length of the distal hypotube and about <NUM> times the length of deflection of the proximal hypotube. Flexibility can be measured in other ways as would be appreciated and understood by a person of ordinary skill in the art. When the delivery member 10a, 10b is assembled, the coiled section 200a, 200b and sleeve <NUM> can be more flexible than the distal hypotube and the proximal hypotube as flexibility is determined by other means as would be known to a person of ordinary skill in the art.

Delivery members 10a, 10b manufactured according to the illustrations in <FIG> are demonstrated to have a flexibility of about <NUM>% to about <NUM>% greater than competing delivery systems.

Comparing the delivery member 10a illustrated in <FIG> to the delivery member 10b illustrated in <FIG>, in <FIG>, the loop wire 400a is illustrated as having a first end attachment 406a to the proximal tube <NUM> and a second end attachment 408a to the distal tube <NUM> while, in <FIG>, the loop wire 400b is illustrated as having a first and second end attachment 406b, 408b both to the proximal tube <NUM>. Although several factors can contribute to the flexibility of the delivery member, all else being equal, the delivery member 10a illustrated in <FIG> can be more flexible compared to the delivery member 10b illustrated in <FIG> because the delivery member 10a illustrated in <FIG> has a single leg of loop wire 400a passing through the coiled section 200a and therefore less material passing through the coiled section 200a compared to the delivery member 10b of <FIG> which has two legs of the loop wire 400b passing through the coiled section 200b. Alternative configurations are also contemplated, for instance the loop wire need not have two separable ends, e.g. the legs of the loop wire can be fused, twisted, or otherwise formed as a single unit.

<FIG> illustrate component parts of an example delivery system with the sleeve <NUM> illustrated in <FIG>, the loop wire 400a illustrated in <FIG>, and an assembly including the proximal tube <NUM>, coiled section 200b, and distal tube <NUM> in <FIG>. Comparing the example delivery member 10a illustrated in <FIG> to the component parts illustrated in <FIG>, in <FIG>, the winding of the coiled section 200a has a substantially square shaped cross section while, in <FIG>, the winding of the coiled section 200b has a substantially circular cross section. The coiled wire can be formed of a substantially linear wire that is wound in a coil shape and/or a hypotube that is laser cut in a spiral pattern. If the coiled wire is formed from a laser cut hypotube, the spiral can be absent interference cuts connecting windings in the coil so as to provide a more flexible coil. A coiled section formed from a laser cut hypotube can have a substantially square shaped cross section as illustrated by the coiled section 200a in <FIG>. A coiled section formed from a linear wire wound into a coil shape can have a substantially circular cross section as illustrated by the coiled section 200b in <FIG>.

Comparing the exemplary delivery member 10a illustrated in <FIG> to the component parts illustrated in <FIG>, in <FIG>, the proximal hypotube <NUM> can include a flexible section <NUM> having material removed to increase flexibility of the flexible section <NUM>. The flexible section <NUM> can be cut in a spiral pattern. The spiral pattern of the flexible section <NUM> can lack interference cuts connecting windings within the spiral. The proximal attachment end 406a of the loop wire <NUM> can be attached to the proximal tube <NUM> in the proximal direction relative to the flexible section <NUM> of the proximal tube <NUM>. The loop wire 400a can thereby inhibit elongation of the flexible section <NUM> of the proximal tube <NUM> and coiled section 200b. The sleeve <NUM> can cover at least a portion of the flexible section <NUM> to inhibit deformation of the flexible section and/or reduce friction with vasculature and the flexible section <NUM> during intravascular navigation. In some examples, the sleeve <NUM> can cover about <NUM> of the proximal tube <NUM> approximate and/or including the distal end <NUM> of the proximal tube <NUM>.

Referring collectively to <FIG>, the coiled section 200a, 200b can be formed separately from the proximal hypotube <NUM> and/or the distal hypotube <NUM>. The separately formed coiled section 200a, 200b can be affixed with welds <NUM>, <NUM> or other appropriate attachment to the proximal tube <NUM> and/or the distal tube <NUM>. Alternatively, or additionally, at least a portion of the coiled section can be formed from a spiral laser cut portion of a hypotube. A separately formed coiled section 200b can be made more flexible compared to a spiral cut tube 200a by selecting a wire with a particular cross section (e.g. circular) with a particular diameter D, or by selecting a wire with material properties to increase flexibility. Conversely, a laser cut portion 200a can be more easily fabricated by cutting a single hypotube to form the proximal tube <NUM>, coiled section 200a, and distal hypotube <NUM>, reducing or eliminating welds <NUM>, <NUM> or other attachments. In either case, the wire of the coil 200a, 200b can have a diameter D or width W measuring within a range including about <NUM> mils and <NUM> mils (about <NUM> to about <NUM>).

The coiled section can be formed primarily of a non-radiopaque material such as steel and can include a radiopaque section <NUM> made of a radiopaque material such as platinum and/or tungsten. The radiopaque section <NUM> can be positioned between a proximal, non-radiopaque section of the coil <NUM> and a distal, non-radiopaque section of the coil <NUM>. The radiopaque section <NUM> can be positioned a predetermined distance from a distal end <NUM> of the delivery member 10a, 10b so that a physician can readily visualize the placement of the distal portion of the delivery member during a treatment procedure. The proximal section <NUM>, radiopaque section <NUM>, and distal section <NUM> can be concentrically welded.

The coiled section 200a, 200b can be surrounded by a flexible sleeve or fused jacket <NUM>, referred generically herein as a "sleeve". The sleeve can inhibit the coil 200a, 200b from expanding radially and/or from engaging vascular walls during navigation. The sleeve <NUM> can include a polymer. The polymer can include additives to increase the lubricity of the sleeve <NUM> so that the sleeve can easily slide through a body vessel. As illustrated in FIG. 2A, the sleeve <NUM> can have a wall thickness T measuring within a range including about <NUM> mils and about <NUM> mils (about <NUM> to about <NUM>). The sleeve <NUM> can further be coated with a hydrophilic coating to further minimize friction during intravascular navigation. The sleeve <NUM> can be fused or glued to the coil 200a, 200b, the proximal hypotube <NUM>, and/or the distal hypotube <NUM>.

The proximal tube <NUM> can extend a majority of the length of the delivery member 10a, 10b with the coiled section 200a, 200b and distal tube <NUM> forming a length L sufficient to absorb a majority of push-back that can occur during placement of an implant at a treatment site. When the proximal tube includes a flexible section <NUM>, the length L can include the distal tube <NUM>, coiled section 200a, 200b, and the flexible section <NUM> of the proximal tube, measured from the proximal end of the flexible section <NUM> to the distal end of the distal tube <NUM>. In some examples, the length L can measure between about <NUM> and about <NUM>, or more specifically, about <NUM>.

In some examples, it can be advantageous to have a relatively stiff proximal hypotube <NUM>, a relatively flexible distal compressible tube <NUM>, and a flexible coil 200a, 200b and sleeve <NUM> assembly that is more flexible than both the proximal hypotube <NUM> and the distal compressible tube <NUM>. The proximal hypotube <NUM> can be sufficiently stiff over a majority of its length to resist kinking while being pushed through the microcatheter. The flexible coil 200a, 200b and distal compressible tube <NUM> can each be sufficiently flexible to reduce the effects of push-back when an implant <NUM> is being placed in an aneurysm. Because the flexible coil 200a, 200b need not be compressibly resilient, the flexible coil can have greater flexibility than the distal compressible tube.

In some examples, the flexible coil 200a, 200b and sleeve <NUM> assembly can be about <NUM>% more flexible than the distal compressible tube <NUM>. In some examples, the flexible coil 200a, 200b and sleeve <NUM> assembly can be about <NUM> times more flexible than the proximal hypotube <NUM>. Flexibility can be measured using a three-point bend test or other appropriate test as would be appreciated and understood by a person of ordinary skill in the art. Generally, a three-point bend test can be performed by fixing a tube portion at two points and applying a force in between the two points. Flexibility can be quantified by a length of displacement of the tube portion for a predetermined force and/or by a magnitude of force to displace the tube by a predetermined length.

<FIG>, and <FIG> each illustrate an implant <NUM> secured to a delivery member 10a, 10b, <NUM> by a mechanical engagement system including the loop wire 400a, 400b, <NUM> and an inner elongated member <NUM> that can be manipulated at the proximal end by a physician to deploy the implant <NUM>. Such a wire or inner elongated member is referred to herein generically as a "pull wire" <NUM>. Referring collectively to <FIG>, and <FIG>, the combination of the coil 200a, 200b, sleeve <NUM>, and loop wire <NUM>, 400a, 400b can provide a highly flexible distal portion of a delivery member <NUM>, 10a, 10b suitable for navigating tortuous anatomy, including neurovascular blood vessels. The loop wire <NUM>, 400a, 400b can support the coil 200a, 200b to prevent the coil 200a, 200b from significantly elongating during navigation of a blood vessel, thereby reducing tension on the pull wire's <NUM> engagement to the loop opening <NUM> and reducing the likelihood of premature deployment of an attached medical treatment device <NUM>.

Referring collectively to <FIG>. <FIG>, and <FIG>, the distal tube <NUM> can include a compressible portion <NUM>. The compressible portion <NUM> can be axially adjustable between an elongated condition and a compressed condition. The compressed portion <NUM> can be formed from a spiral-cut portion of the tube <NUM>, formed by a laser cutting operation. Additionally, or alternatively, the compressible portion can be formed of a wound wire, spiral ribbon, or other arrangement allowing axial adjustment according to the present invention. Preferably, the compressible portion <NUM> is in the elongated condition at rest and automatically or resiliently returns to the elongated condition from a compressed condition, unless otherwise constrained.

<FIG> are a time sequence set of illustrations depicting release of a medical device (e.g. implant) <NUM> from a delivery member <NUM>. The delivery member <NUM> can be configured such as illustrated in <FIG> and otherwise described herein. <FIG> illustrates an engagement system including the loop wire <NUM> and pull wire <NUM> locked into a locking portion <NUM> of the medical device <NUM>. The compressible portion <NUM> of the distal tube <NUM> can be compressed and the loop wire <NUM> opening <NUM> at a distal end <NUM> of the loop wire <NUM> can be placed through the locking portion <NUM>. When the pull wire <NUM> is put through the opening <NUM> the medical device <NUM> is now secure. <FIG> illustrates the pull wire <NUM> being drawn proximally to begin the release sequence for the medical device <NUM>. <FIG> illustrates the instant the distal end <NUM> of the pull wire <NUM> exits the opening <NUM> and the pull wire <NUM> is pulled free of the loop wire <NUM>. The distal end <NUM> of the loop wire <NUM> falls away and exits the locking portion <NUM>. As can be seen, there is now nothing holding the medical device <NUM> to the detachment system <NUM>. <FIG> illustrates the end of the release sequence. Here, the compressible portion <NUM> has extended/returned to its original shape and "sprung" forward. An elastic force E is imparted by the distal end <NUM> of the distal tube <NUM> to the medical device <NUM> to "push" it away to ensure a clean separation and delivery of the medical device <NUM>.

The compressible portion <NUM> can have a difference in length (distance of compression) when measured in the compressed configuration and the original, uncompressed configuration of about <NUM> to about <NUM>. Greater elastic force E can be achieved by using a greater distance of compression. The distance of compression can be determined by the sizing of the loop wire <NUM>, the shape of the locking portion <NUM>, and the shape of the distal end <NUM> of the distal tube <NUM>.

<FIG> is a flow diagram outlining example method steps of a method <NUM> for treating an aneurysm. Steps <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are generally directed toward designing, constructing, or configuring a delivery system such as an example system presented herein, a variation thereof, and alternative implant delivery systems as would be appreciated and understood by a person of ordinary skill in the art. Steps <NUM>, <NUM>, <NUM>, and <NUM> are directed toward delivering and deploying an implant with the delivery system designed, constructed, or configured according to one or more of the preceding method steps.

In step <NUM>, a proximal tube, coiled wire, and a compressible distal tube can be connected such that the assembly is substantially tubular and has a contiguous lumen extending through the assembled sections. The proximal tube, the coiled wire, and the compressible distal tube can each respectively be a proximal tube <NUM>, support coil 200a, 200b, and distal hypotube <NUM> such as described and/or illustrated herein, a variation thereof, or an alternative as would be appreciated and understood by a person of ordinary skill in the art.

In step <NUM>, a sleeve can be positioned along the coiled wire. The sleeve can be a sleeve <NUM> such as described and/or illustrated herein, a variation thereof, or an alternative as would be appreciated and understood by a person of ordinary skill in the art. The sleeve can be positioned to surround a portion of the length of the coiled wire, or the entire length of the coiled wire. The sleeve can also be positioned to extend to cover a respective portion of one or both of the proximal tube and the distal tube.

In step <NUM>, a loop wire can be affixed to the proximal tube. The loop wire can be a loop wire <NUM>, 400a, 400b such as described and/or illustrated herein, a variation thereof, or an alternative as would be appreciated and understood by a person of ordinary skill in the art. The loop wire can have two ends, at least one of the two ends can be affixed to the proximal tube in step <NUM>, and a loop opening can be defined as a bend in the loop wire between the two ends. An end not affixed to the proximal tube in step <NUM> can be affixed to the delivery member at the distal tube or other location. Alternatively, the loop wire can have a single end that is affixed to the proximal tube in step <NUM> and a loop opening formed at an opposite end of the loop wire.

In step <NUM>, the loop opening of the loop wire can be positioned at a distal end of the distal tube. The loop opening can be positioned as described and/or illustrated herein or otherwise positioned to facilitate attachment of an implant at the distal end of the distal tube.

In step <NUM>, the compressible distal tube can be compressed.

In step <NUM>, an implant can be secured to the compressed distal tube by passing the loop opening through an engagement feature (locking portion or opening) on the implant and passing a pull wire through the loop opening.

In step <NUM>, the implant can be delivered to a treatment site. The implant can be an implant <NUM>, 10a, 10b as described and/or illustrated herein, a variation thereof, or an alternative medical treatment device as would be appreciated and understood by a person of ordinary skill in the art. The implant can be delivered by means known to a person of ordinary skill in the art. In some examples, the treatment site can be an intravascular treatment site such as an aneurysm or lesion. The implant can be delivered through a catheter positioned intravascularly. A portion of a delivery system (e.g. the proximal tube) can be accessible by a physician such that the physician can push the delivery system into the patient and through the catheter. The implant can be attached at the distal end of the delivery system and pushed by the delivery system as the delivery system is pushed by the physician further into the catheter.

In step <NUM>, the sleeve can inhibit radial expansion of the coil as the implant is being delivered to the treatment site. The sleeve can inhibit radial expansion of the coil by means described herein, variations thereof, or alternatives as would be appreciated and understood by a person of ordinary skill in the art.

In step <NUM>, longitudinal expansion of the coiled wire can be inhibited with the loop wire during delivery of the implant. The loop wire can be stretch resistant and be positioned such that the loop wire does not significantly elongate during delivery of the implant.

In step <NUM>, the implant can be released by retracting the pull wire. When a physician retracts the pull wire, the distal end of the pull wire can move proximally to exit the loop opening. Once the loop wire is no longer held in place by the pull wire, the loop wire can retract from the locking portion on the implant, thereby releasing the implant.

Claim 1:
A delivery member (10a, 10b) for delivering an implantable medical device to a target location of a body vessel, the delivery member comprising:
a proximal hypotube (<NUM>);
a flexible coil (200a, 200b) extending from a distal end of the proximal hypotube (<NUM>);
a compressible distal hypotube (<NUM>) extending from a distal end of the flexible coil (200a, 200b);
a lumen (<NUM>) extending from a proximal end of the proximal hypotube (<NUM>), through the proximal hypotube (<NUM>), through the flexible coil (200a, 200b), through the compressible distal hypotube (<NUM>), and to a distal end (<NUM>) of the compressible distal hypotube (<NUM>);
a sleeve (<NUM>) extending along a majority of the flexible coil (200a, 200b),
wherein the sleeve (<NUM>) is effective to inhibit radial expansion of the flexible coil (200a, 200b); and
a loop wire (400a, 400b) comprising a first end (406a) affixed to the proximal hypotube (<NUM>) and comprising a loop opening (<NUM>) positioned approximate a distal end (<NUM>) of the compressible distal hypotube (<NUM>),
wherein the loop wire (400a, 400b) is effective to inhibit longitudinal elongation of the flexible coil (200a, 200b); the delivery member further comprising:
a pull wire (<NUM>) extending through the lumen (<NUM>),
wherein the loop wire (400a, 400b) and the pull wire (<NUM>) are positioned to secure the implantable medical device to the delivery system, and
wherein the loop wire (400a, 400b) and the pull wire (<NUM>) are movable to release the implantable medical device from the delivery system, wherein the loop wire (400a, 400b) is stretch resistant, and
wherein the loop wire (400a, 400b) is under tension when the implantable medical device is secured to the delivery system.