Patent Description:
Implantable intravascular treatment devices are commonly used in the endovascular procedures or treatments of various vascular ailments, for example, brain aneurysms. A catheter is inserted into the femoral artery in patient's leg and guided by imaging navigated through the vessel to the target site in the brain where the aneurysm is located (<FIG>). With the distal end of the catheter properly positioned on a proximal side of the aneurysm, a microcatheter is tracked through the catheter to the proximal side of the aneurysm. A delivery and deployment system loaded with an implantable intravascular treatment device (e.g., embolic coil) is introduced via the microcatheter to the target site. During delivery to the target site, the implantable intravascular treatment device is secured within the delivery and deployment system via a securement wire. When properly positioned at the target site (e.g., at the location of the aneurysm) the implantable intravascular treatment device (e.g., embolic coil) is severed from the wire and thereby deposited within the aneurysm (<FIG>). Severing of the embolic coil from the securement wire is typically achieved by passing of a small electrical current through the wire. This process is repeated until the area of the vessel with the weakened wall is tightly packed with numerous embolic coils occluding blow flow thereto thereby preventing rupture (<FIG>).

<CIT> discloses a delivery and detachment system comprising an outer tube enclosing three bushings and a slider. The slider being slidably received in a first bushing, which is welded to the outer tube, and a second bushing, disposed proximally to the first bushing and is welded to the slider, being slidably received in the outer tube. Wherein the slider is temporarily fixed to the first bushing with a tack weld. The delivery and detachment system further comprising a cord received within a lumen of and secured to the slider, and configured to releasably secure an implant.

The present invention is directed to an improved system for reliable delivery of the implantable intravascular treatment device to a desired location in the vessel and ensuring consistent deployment when properly positioned at the target site.

The present invention is directed to a delivery and detachment system for an implantable intravascular treatment device. The system includes an outer delivery tube with a proximal end, an opposite distal end, and a lumen extending axially therethrough; the outer delivery tube having a radially inward stopping member. In addition, the system further includes a proximal inner tube telescopically receivable in the distal end and axially slidable in a proximal direction within the lumen of the outer delivery tube. The proximal inner tube has a proximal end, an opposite distal end, and a channel extending axially therethrough. Specifically, the proximal inner tube comprises a proximal section including the proximal end of the proximal inner tube and a distal section including the distal end of the proximal inner tube; wherein the proximal section and the distal section have different outer diameters forming a transition in outer diameter at an interface therebetween. In turn, the distal section of the proximal inner tube itself comprises two distal section components connected by an axially separable region; wherein the two distal section components comprise a first distal section component including the transition and a second distal section component arranged in a distal direction relative to the first distal section component. Still further the system includes a restricting element arranged between an outer surface of the second distal section component and an inner wall of the lumen of the outer delivery tube. When the axially separable region is axially separated: (i) the proximal section of the proximal inner tube is slidable in a proximal direction through the stopping member until the transition in the outer diameter of the first distal section component attached thereto engages the stopping member prohibiting axial movement in the proximal direction; and (ii) the restricting element maintaining in position the second distal section component within the outer delivery tube.

The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings illustrative of the invention wherein like reference numbers refer to similar elements throughout the several views and in which:.

In the description, the terms "distal" or "proximal" are used in the following description with respect to a position or direction relative to the treating physician or medical interventionalist. "Distal" or "distally" are a position distant from or in a direction away from the physician or interventionalist. "Proximal" or "proximally" or "proximate" are a position near or in a direction toward the physician or medical interventionist. The terms "occlusion", "clot" or "blockage" are used interchangeably.

<FIG> is a side view of the assembled present inventive delivery and deployment system <NUM> that includes an outer delivery tube (e.g., pusher) <NUM> open at both ends (e.g., proximal end <NUM> and opposite distal end <NUM>) with a lumen <NUM> extending axially therethrough. A proximal inner tube <NUM> (e.g., proximal member) is telescopically slidable in an axial direction through the lumen <NUM> of the outer delivery tube <NUM>, as illustrated in <FIG> (representing an enlarged longitudinal cross-sectional view of proximal section VI of <FIG>). The maximum outer diameter of the proximal inner tube <NUM> is sized to be receivable and freely axially (longitudinally) slidable within the lumen <NUM> of the outer delivery tube <NUM>. A stopping member <NUM> (i.e., crimping, projection or protrusion) (e.g., having a V-shape, hemispherical, square, rectangular or other cross-sectional geometric shape) extends radially inward from an inner wall of the outer delivery tube <NUM> thereby reducing the inner diameter of the lumen <NUM> at the stopping member.

The proximal inner tube <NUM> alone is depicted in <FIG> to include a proximal section <NUM> having a uniform first outer diameter (D1) and a distal section <NUM> having a uniform second outer diameter (D2), wherein D2 > D1 forming the transition <NUM> (i.e., shoulder or ground shelf) in outer diameter at the interface between the proximal and distal sections <NUM>, <NUM>, respectively. Proximal inner tube <NUM> has a uniform inner diameter from its proximal end <NUM> to its opposite distal end <NUM> defining a channel <NUM> therethrough. The wall thickness of the proximal section <NUM> is smaller (thinner in a radial direction) relative to the wall thickness of the distal section <NUM>. The first outer diameter (D1) of the proximal section <NUM> is sized to slide freely in an axial direction through and beyond the stopping member <NUM> extending radially inward in the lumen <NUM> of the outer delivery tube <NUM>, whereas a second outer diameter (D2) of the distal section <NUM> of the inner tube <NUM> is greater than the inner diameter of the stopping member <NUM>. As a result of the variation in outer diameter of the proximal inner tube <NUM>, axial movement of the proximal inner tube <NUM> relative to the outer delivery tube <NUM> is restricted when the transition <NUM> and the stopping member <NUM> directly physically contact/engage one another. Transition <NUM> in the exemplary configuration shown in <FIG> is tapered (sloped) between the proximal and distal sections <NUM>, <NUM>, respectively. Alternatively, a step transition is also contemplated and within the intended scope of the present invention. Other geometric configurations for the transition <NUM> in outer diameter between the proximal and distal sections of the inner tube are possible. Preferably, the profile of the stopping member <NUM> and transition <NUM> complement or mirror one another (e.g., the stopping member <NUM> is V-shape and the transition <NUM> is tapered (sloped) at a complementary angle). At all times during the delivery and deployment of the implantable intravascular treatment device in the artery of the body the outer delivery tube <NUM> remains linear or straight (i.e., unbent) and intact (i.e., not broken or severed) to allow unimpeded axial (longitudinal) pulling in a proximal direction of the proximal end <NUM> of the proximal inner tube <NUM> through the lumen <NUM> of the outer delivery tube <NUM> until further proximal movement is halted when the transition <NUM> and stopping member <NUM> physically contact/engage one another. Direct engagement of the transition <NUM> with the stopping member <NUM> in the present inventive design advantageously ensures the proximal inner tube <NUM> once severed along the severable (weakened) region remains self-contained within and prevented from falling out from the proximal end of the outer delivery tube <NUM>, as described in further detail below.

Still referring to <FIG>, distal section <NUM> of proximal inner tube <NUM> comprises a cylindrical tube including two components 250a, 250b (hereinafter referred to as first and second distal section components, respectively) having an axially separable (e.g., axially severable) region 250c disposed therebetween.

The stopping member <NUM> is located a predetermined distance in a proximal direction from the transition <NUM> (when the assembled delivery and detachment device is in the delivery state) so that before engaging one another sufficient axial movement in a proximal direction of the first distal section component 250a relative to the stationary second distal section component 250b is permitted to release the implantable intravascular treatment device <NUM>.

In the exemplary configuration of <FIG> axially severable region 250c comprises a plurality of frangible struts or connectors <NUM> spanning between the respective two distal section components 250a, 250b (i.e., opposite ends of each strut connected to one of the respective two distal section components 250a, 250b). The frangible struts or connectors <NUM>, for example, represent those remaining sections created following a series of cuts (preferably laser cuts) made radially inward through the cylindrical tube of the distal section <NUM>. In the Figures black lines denote the frangible struts or connectors <NUM> while the white areas between adjacent black struts or connectors represent regions where the material of the cylindrical tube of the distal section <NUM> of the proximal inner tube <NUM> has been cut or removed (e.g., via laser cuts). These plurality of radially inward cuts through the distal section <NUM> of the proximal inner tube creates the severable region or interface 250c that is "weakened" relative to the remaining components 250a, 250b comprising distal section <NUM> on either side thereof that is devoid or absent of cuts. Second distal component 250b is maintained in position within the outer delivery tube <NUM> via a restricting element <NUM> (e.g., an adhesive joint, weld joint or O-ring) preventing or minimizing gross movement in axial direction therein. In the case of an O-ring or other mechanical restricting element the component is preferably maintained in its axial position (e.g., sandwiched between projections). Upon application of a sufficient axial force (e.g., pulling in a proximal direction on the proximal end or sliding) on the proximal inner tube <NUM>, the struts or connectors <NUM> within the axially severable weakened region 250c break/rupture/sever such that the two distal section components 250a, 250b are no longer connected to one another (i.e., break apart). Once the struts or connectors <NUM> are severed, the first distal section component 250a and proximal section <NUM> attached thereto or integral therewith together as a unit are axially slidable in a proximal direction until the transition <NUM> and stopping member <NUM> directly engage/physically contact one another. The second distal section component 250b (furthest from the proximal section <NUM>) is maintained in place within the lumen <NUM> of the outer delivery tube <NUM> by the restricting element <NUM>.

<FIG> shows an exemplary axially severable region 250c having a plurality of parallel angled connectors or struts <NUM> formed by a radial spiral cut penetrating radially inward through the proximal inner tube <NUM> from its outer surface to the channel <NUM> defined axially therethrough. Other arrangements or patterns (parallel, non-parallel, random, linear, curved, angular, etc.) of the plurality of struts or connectors <NUM> in the axially severable (weakened) region or interface 250c are contemplated and within the scope of the present invention including, but not limited to, a chevron V-pattern (<FIG>), an angular pattern relative to the longitudinal axis of the inner tube (<FIG>), or an intersecting or cross-over (e.g., X-pattern) (<FIG>). The struts or connectors <NUM> in the patterns represented in <FIG> extend/run in an axial direction (longitudinally) spanning between the two distal section components 250a, 250b; however, the struts and connectors <NUM> disposed between the two distal section components 250a, 250b (as shown in <FIG>) may be arranged as a radial pattern with offset auxiliary/supplemental struts or connectors extending (running) between adjacent radial rows in an axial (longitudinal) direction. The number (i.e., two or more), spacing between, as well as the dimensions and pattern of the struts or connectors may be modified, as desired, to prevent premature rupture during delivery yet, upon application of a predetermined axial force on the proximal end of the proximal inner tube, ensure reliable and complete deployment/detachment (e.g., breakage, rupture, freeing) of the implantable intravascular treatment device at an intended location within the artery (once properly positioned at the target site).

Rather than be severable, in an alternative configuration illustrated in <FIG> axial section 250c may be expandable in an axial direction (without severing, rupturing or breaking) wherein the two distal section components 250a, 250b remain fixedly connected to respective ends of a helical spring <NUM>' disposed therebetween. When the interventionalist pulls in a proximal direction on the proximal end or slides in a proximal direction the proximal inner tube <NUM> the helical spring <NUM>' elongates or expands in an axial direction without breaking/rupturing/severing/disconnecting from the respective distal section components 250a, 250b. In all other respects the two embodiments (e.g., axially severable region including frangible struts vs. axially expandable region including an axially expandable helical spring) are the same and the description herein is applicable for both. Other types of axially expandable mechanical devices may be substituted for the helical spring. Rather than a separate component helical spring <NUM>' (as depicted in <FIG>), a helical or spiral cut (e.g., laser cut) may be made to the proximal inner tube <NUM> along axial section 250C acting in a similar manner.

The implantable intravascular treatment device (e.g., embolic coil) is attached to the delivery and detachment system via a releasable securement mechanism that is released exclusively via mechanical translation (e.g., movement in an axial or longitudinal direction and/or torque) without the need for application of electrical and/or thermal heat.

The present inventive delivery and detachment system is used by the interventionalist to deliver and deposit the implantable intravascular treatment device to the target site in the artery. Maintaining the proper position of the securement wire during delivery of the implantable intravascular treatment device to the target site within the vessel followed thereafter by complete detachment or release of the implantable intravascular treatment device for deposit at the desired target location in the body are instrumental factors in ensuring the success of the endovascular treatment procedure. Undesirable gross shifting, translation, or movement of the securement wire during delivery (prior to deployment/detachment/release) of the implantable intravascular treatment device at the target site may result in damage or injury to the vessel wall. At the time of deployment when the implantable intravascular treatment device is properly located at the target site in the vessel, hampering or total failure in detachment/release of the implantable intravascular treatment device from the wire to which it is secured may result in procedural delay and potentially require withdraw of the implantable intravascular treatment device altogether to be replaced by another. Either potential problem, under certain circumstances, may result in delay, injury to the patient and under some circumstances possibly death. With these goals in mind, the present inventive delivery and detachment system minimizes gross movement of the securement wire during delivery resulting in precise deposit at the target site while allowing fine tuning of the axial force (e.g., pulling) in a proximal direction to reliably release (deploy) the implantable intravascular treatment device. The present inventive integrated and simplified system design provides precise (accuracy of positioning) and safe (minimizing the potential for injury) control during both delivery and detachment/deployment of the implantable intravascular treatment device within the vessel.

Referring to <FIG>, the illustrated exemplary releasable securement mechanism includes a securement wire (e.g., pull wire) <NUM> extending axially through the detachment and deployment system. A proximal end of the securement wire <NUM> is fixedly attached to the proximal end <NUM> of the proximal inner tube <NUM> via a proximal bead <NUM> (<FIG>). An opposite distal end of the securement wire <NUM> is releasably secured to the implantable intravascular treatment device (e.g., embolic coil) <NUM> via the releasable securement mechanism. Specifically, a loop wire <NUM> extends in an axial direction through the lumen <NUM> of the proximal inner tube <NUM>. The loop wire <NUM> is preferably U-shape having two proximal ends secured to a detachment tube <NUM> (<FIG>) and a closed distal end (forming a loop) that is threaded through (e.g., bent upwards at an acute angle, preferably perpendicular, relative to the axial direction through the lumen <NUM>) an opening of a proximal key <NUM> (<FIG>). A sufficient amount of the closed end of the loop wire <NUM> extends perpendicularly through the opening of the proximal key <NUM> forming a loop through which the free distal end of the securement wire <NUM> is axially slidable in a distal direction securing the proximal key <NUM> to the distal end of the delivery and detachment system. The opposite distal end of the proximal key <NUM> is received within a cavity at the proximal end of the embolic coil <NUM> and secured in position by a stretch restraint fiber <NUM> attached to a distal bead or cap <NUM>.

Operation of the present inventive delivery and detachment system depicted in the figures are representative of various sequential states of operation i.e., delivery, detachment, and deposit of the implantable intravascular treatment device, each of which is described in detail.

<FIG> depict the present inventive intravascular delivery and deployment system <NUM> loaded with the implantable intravascular treatment device (e.g., embolic coil) <NUM> while in a "delivery state", that is, the state while tracking (delivering) the implantable intravascular treatment device (e.g., embolic coil) to a target site in the vessel/artery. Specifically, the releasable securement mechanism securing the implantable intravascular treatment device (e.g., embolic coil) to the distal end of the delivery and detachment system <NUM> is illustrated in the cutaway distal section view of <FIG>. The opposite proximal section of the delivery and detachment system with the proximal inner tube <NUM> telescopically assembled within the outer delivery tube <NUM> is shown in the axial cross-sectional view of <FIG>. While in the "delivery state" this embodiment of the present inventive delivery and deployment system <NUM> exhibits the following characteristics: (i) the implantable intravascular treatment device (e.g., embolic coil) <NUM> is mechanically attached, secured or connected via the releasable securement mechanism (e.g., pull wire <NUM>, proximal key <NUM>, and stretch resistant fiber <NUM>) to the distal end of the delivery and detachment system; (ii) the two distal section components 250a, 250b comprising distal section <NUM> of the proximal inner tube <NUM> are connected, secured or attached to one another via the severable (weakened) region or interface 250c which is intact and complete (non-ruptured, non-severed); (iii) transition <NUM> of the proximal inner tube <NUM> and stopping member <NUM> in the outer delivery tube <NUM> are separated from one another in an axial/longitudinal direction by a maximum distance; and (iv) the proximal end <NUM> of the outer delivery tube <NUM> and proximal end <NUM> of proximal inner tube <NUM> are separated from one another in an axial/longitudinal direction by a minimum distance. Shielded within the channel <NUM> of the proximal inner tube <NUM> which, in turn, is stabilized within the lumen <NUM> of the outer delivery tube <NUM> via the restricting element <NUM> (e.g., adhesive joint, weld joint or O-ring), gross movement or translation of the securement wire <NUM> during delivery of the implantable intravascular treatment device to the target site in the artery is minimized or prevented.

Once the implantable intravascular treatment device (e.g., embolic coil) is located at the target site within the artery, the interventionalist transitions the delivery and detachment system to the next state, hereinafter referred to as a "deployment state" or "detachment state. " In order to transition states, the interventionalist subjects the proximal inner tube <NUM> to movement (e.g., a pulling or sliding force) in a proximal direction relative to that of the outer delivery tube <NUM>.

Deployment begins by manually rupturing (e.g., manually snapping) the struts or connectors <NUM> in the axially severable (weakened) region 250c upon the application of sufficient axial force on the proximal inner tube <NUM> in a proximal direction. Specifically, the particular pattern of the struts or connectors <NUM> formed in the cylindrical inner tube after making the radially inward laser cuts is specifically designed to break, sever, detach or rupture when the proximal inner tube <NUM> is subject to a predetermined force (e.g., pulling/sliding) in a proximal direction. For this particular design having the axially severable region 250c there is preferably no intended allowance for preliminary stretching in an axial or longitudinal direction of the struts relative to one another before breaking. In other words, in this particular embodiment movement of the proximal inner tube in a proximal direction is for the sole purpose and intent of breaking or severing of the frangible connectors <NUM>.

While in the deployment state, a series of cutaway views of the distal section is shown in <FIG> during various sequential stages of retraction (movement) in a proximal direction of the proximal inner tube <NUM>. Deployment is accomplished via application of a simplified hand movement exclusively or solely in an axial direction applied to the proximal inner tube making the system user friendly by the interventionalist. Sufficient linear force is applied to rupture or break the frangible struts or connectors <NUM> within the axially severable (weakened) region or interface 250c permanently severing the distal end <NUM> into its respective two distal section components 250a, 250b. Specifically, the two distal section components comprise a first distal component 250a including the transition <NUM> and a second distal section component 250b arranged in a distal direction relative to the first distal section component 250a.

At the time of rupture of the struts or connectors <NUM>, the distal end of the securement wire <NUM> is retained/secured (e.g., threaded or passed) through the opening at the closed distal end of the U-shape loop wire <NUM> that is bent upwards through the opening in the proximal key <NUM>, as shown in <FIG>. Continued retraction (i.e., movement in an axial direction) of the proximal inner tube <NUM>, causes the securement wire <NUM> connected thereto via the proximal bead <NUM> to simultaneously therewith move in the same direction (as shown in <FIG>). At this stage the implantable intravascular treatment device <NUM> (e.g., embolic coil) is still retained/secured/attached to the distal end of the delivery and detachment system via the bent upwards U-shape loop wire <NUM> threaded through the opening of the proximal key <NUM>. While still further retraction (i.e., axial movement in a proximal direction) of the proximal inner tube <NUM> completely withdraws freeing the distal end of the securement wire <NUM> from the bent upwards U-shape loop wire <NUM> allowing the U-shape loop wire to substantially straighten (substantially axial or linear) clearing/freeing/releasing it from the proximal key <NUM> (as shown in <FIG>).

The opposite distal end of the delivery and detachment system during the deployment state is shown in <FIG> denoting via the arrows the pulling (i.e., movement in a proximal direction) of the proximal inner tube <NUM> and the ruptured struts <NUM> (i.e., axial separation between the first and second distal section components 250a, 250b, respectively). As is also evident from <FIG>, following rupture of the struts <NUM>, the second severed distal section 250b remains securely in position within the outer delivery tube <NUM> via the restricting element <NUM>.

During the "deployment state," sufficient axial force in a proximal direction is imparted on the proximal inner tube so that the delivery and detachment system exhibits the following characteristics: (i) the two distal section components 250a, 250b comprising distal section <NUM> are detached/ruptured/severed/broken apart of one another (i.e., the struts/connectors <NUM> in the severable (weakened) region or interface 250c are severed, broken, detached from one another); (ii) the releasable securement mechanism is released freeing the implantable intravascular treatment device at its current position within the artery; (iii) transition <NUM> of the proximal inner tube <NUM> and stopping member <NUM> in the outer delivery tube <NUM> are separated (not engaging/contacting) from one another in an axial/longitudinal direction by a distance less than the maximum distance (while in the "delivery state" of <FIG>); and (iv) the proximal end <NUM> of the outer delivery tube <NUM> and proximal end <NUM> of the proximal inner tube <NUM> are separated from one another in an axial/longitudinal direction by a distance greater than the minimum distance (while in the "delivery state" of <FIG>).

During the transition from the detachment to the deposit state, with the U-shape loop wire <NUM> no longer secured to (free and clear of) the proximal key <NUM>, a pre-load of the outer delivery tube <NUM> pushes or advances (as depicted by the arrow in <FIG> & <FIG>) in a distal direction the implantable intravascular treatment device (e.g., embolic coil) <NUM> away from the loop wire <NUM> facilitating separation of the components from one another. The implantable intravascular treatment device (e.g., embolic coil) <NUM> together with the proximal key <NUM> attached thereto via the stretch resistant fiber <NUM> as a unit remain (e.g., left behind) located/deposited at the target site in the artery.

Referring to the corresponding proximal end shown in <FIG>, during the depositing stage even further retraction (i.e., axial movement in a proximal direction) of the proximal inner tube <NUM> maximizes the axial separation of the first distal section component 250a, relative to that of the second distal section component 250b held in position within the outer delivery tube <NUM> via the restricting element <NUM>. Eventually, retraction of the proximal section <NUM> together with the severed first distal section component 250a as a unit is limited or restricted by the transition <NUM> engaging or contacting the stopping member <NUM> (e.g., crimping or protrusion) (hereinafter referred to as a "halted" state) (<FIG>). While in the "halted state" (<FIG>) this embodiment of the present inventive delivery and detachment system exhibits the following characteristics: (i) the two distal section components 250a, 250b are separated from one another in an axial direction a maximum distance (greater than the distance separation during the deployment state of <FIG>); (ii) the releasable securement mechanism securing the implantable intravascular treatment device (e.g., embolic coil) to the securement wire <NUM> remains released and free from that of the implantable intravascular treatment device at the location in which it is deposited within the artery (which occurred during deployment); (iii) transition <NUM> and stopping member <NUM> contact or engage one another halting further axial movement in a proximal direction of the first distal section component 250a relative to that outer delivery tube <NUM>; and (iv) the proximal end <NUM> of the outer delivery tube <NUM> and proximal end <NUM> of the proximal inner tube <NUM> are separated from one another in an axial/longitudinal direction by a maximum distance greater than the distance in the deployed state (<FIG>)). In the halted state in <FIG> the proximal section <NUM> and the first distal section component 250a together as a unit are prevented from sliding out of the proximal end of the outer delivery tube <NUM> by engagement of the stopping member <NUM> with the transition <NUM>. Thus, despite application of continued pulling force engaging features <NUM>, <NUM> ensure that the proximal section <NUM> and first distal section component 250a integral therewith as a unit nevertheless remain self-contained in the outer delivery tube <NUM>. During the medical treatment procedure, self-containment of the proximal section <NUM> and the first distal section component 250a integral therewith as a unit within the outer delivery tube <NUM> advantageously reduces the number of components or pieces to be withdrawn from the body to thereafter be disposed. While another benefit of the present inventive self-containment feature eliminates possible unwanted catching of the proximal section <NUM> and first distal section component 250a as a unit on other pieces or components of medical equipment used in the procedure.

In an alternative embodiment, rupture of the struts <NUM> in the axially severable weakened section 250c may be realized by subjecting the proximal inner tube to a combination of multiple forces rather than force (movement) exclusively in a linear/axial direction. Specifically, while maintaining the position the outer delivery tube <NUM> the proximal end <NUM> of the proximal inner tube <NUM> may be subject first to torque (rotation) to break the struts <NUM> followed thereafter by a linear/axial force to deploy or release the implantable intravascular treatment device. In this regard, there is no stored energy (e.g., spring) component to the breaking of the struts action (torque), separation or release of the securement wire occurs only via the linear/axial force (pulling), hence the combination of forces. Prior to applying the linear/axial force, the proximal end <NUM> of the proximal inner tube <NUM> together as a unit with the first distal section component 250a integral therewith may be initially subject to torque (rotational) force while the second distal section component 250b of the proximal inner tube <NUM> is maintained in positioned (e.g., resists rotation) by the restricting element <NUM>. Twisting of the first distal section component 250a while the second distal section component 250b remains in place (e.g., resists rotation because of the restricting element <NUM>) cause the struts or connectors <NUM> within the axially severable weakened region 250c to rupture/break/sever. Once the struts or connectors <NUM> have been ruptured/broken/severed/destroyed, thereafter application of a linear/axial force applied in a proximal direction to the proximal section <NUM> together with the first distal section component 250a advancing together as a single unit through the lumen <NUM> of the outer delivery tube <NUM> in a proximal direction. While in yet another alternative embodiment, the proximal end <NUM> of the proximal inner tube <NUM> may be subject to a purely torque force along a spiral path (i.e., unscrewing a screw) that allows for a torque (unwinding action) to apply against and rupture the struts <NUM> while simultaneously following an axial path moving the proximal inner tube in a proximal direction.

Regardless of the force (torque and/or linear/axial), application of an angular force (bending) of the proximal inner tube and/or outer delivery tube either independent of one another or together as a unit at a non-zero angle relative to that of the longitudinal axis extending through the delivery and detachment system <NUM> is to be avoided potentially hampering or altogether preventing sliding of the proximal inner tube relative to the outer delivery tube and unwanted translation of the securement wire.

The operation of the present inventive delivery and detachment system shown in the figures and described above has been for an exemplary configuration in which the first and second distal section components 250a, 250b are connected via an axially severable weakened region 250c comprising a plurality of frangible struts or connectors <NUM> that are severable/breakable/rupturable resulting in divisible, separated, independent (no longer connected to one another when the struts are ruptured) distal section components 250a, 250b. As previously noted, in the alternative configuration shown in <FIG> the two distal section components 250a, 250b are connected one at each end of a linearly expandable or elongated helical spring <NUM>' that never ruptures or severs. During operation (e.g., during the deposit stage) the two distal components are separated axially (when the proximal end of the proximal section <NUM> is subject to an axial force in a proximal direction but remain connected to one another at all times via the axially expanded/elongated spring helical <NUM>' disposed therebetween.

Claim 1:
A delivery and detachment system (<NUM>) for an implantable intravascular treatment device, the system comprising:
an outer delivery tube (<NUM>) with a proximal end (<NUM>), an opposite distal end (<NUM>), and a lumen (<NUM>) extending axially therethrough; the outer delivery tube having a radially inward stopping member (<NUM>);
a proximal inner tube (<NUM>) telescopically receivable in the distal end and axially slidable in a proximal direction within the lumen of the outer delivery tube; the proximal inner tube having a proximal end, an opposite distal end, and a channel extending axially therethrough; the proximal inner tube comprising a proximal section (<NUM>) including the proximal end of the proximal inner tube and a distal section (<NUM>) including the distal end of the proximal inner tube; wherein the proximal section and the distal section have different outer diameters forming a transition (<NUM>) in outer diameter at an interface therebetween; characterized in that the distal section of the proximal inner tube comprises two distal section components connected by an axially separable region (250c); wherein the two distal section components comprise a first distal section component (250a) including the transition and a second distal section component (250b) arranged in a distal direction relative to the first distal section component; and
a restricting element (<NUM>) arranged between an outer surface of the second distal section component and an inner wall of the lumen of the outer delivery tube;
when the axially separable region is axially separated: (i) the proximal section of the proximal inner tube is slidable in a proximal direction through the stopping member until the transition in the outer diameter of the first distal section component attached thereto engages the stopping member prohibiting axial movement in the proximal direction; and (ii) the restricting element maintaining in position the second distal section component within the outer delivery tube.