an occluding device delivery assembly having portions with small cross section ( s ) and which is highly flexible is described herein . fig1 illustrates an introducer sheath 10 according to an aspect of the present invention that receives , contains and delivers an occluding device 100 to a flexible micro - catheter 1 for positioning within the vasculature of an individual . the occluding device 100 can include those embodiments disclosed in copending u . s . patent application ser . no . 11 / 136 , 395 , titled “ flexible vascular occluding device ”, filed on may 25 , 2005 , which is expressly hereby incorporated by reference in its entirety . a distal end 12 of the introducer sheath 10 is sized and configured to be received within a hub 2 of the micro - catheter 1 , as shown in fig1 and 2 . the hub 2 can be positioned at the proximal end of the micro - catheter 1 or at another location spaced along the length of the micro - catheter 1 . the micro - catheter 1 can be any known micro - catheter that can be introduced and advanced through the vasculature of a patient . in an embodiment , the micro - catheter has an inner diameter of 0 . 047 inch or less . in another embodiment , the micro - catheter has an inner diameter of about 0 . 027 inch to about 0 . 021 inch . in an alternative embodiment , the micro - catheter could have an inner diameter of about 0 . 025 inch . however , it is contemplated that the catheter 1 can have an inner diameter that is greater than 0 . 047 inch or less than 0 . 021 inch . after the introducer sheath 10 is positioned within the catheter hub 2 , the occluding device 100 can be advanced from the introducer sheath 10 into the micro - catheter 1 in preparation for deploying the occluding device 100 within the vasculature of the patient . the micro - catheter 1 may have at least one fluid introduction port 6 located adjacent the hub 2 or at another position along its length . the port 6 is preferably in fluid communication with the distal end of the micro - catheter 1 so that a fluid , e . g ., saline , may be passed through the micro - catheter 1 prior to insertion into the vasculature for flushing out air or debris trapped within the micro - catheter 1 and any instruments , such as guidewires , positioned within the micro - catheter 1 . the port 6 may also be used to deliver drugs or fluids within the vasculature as desired . fig3 illustrates the introducer sheath 10 , an elongated flexible delivery guidewire assembly 20 that is movable within the introducer sheath 10 and the occluding device 100 . as shown , the guidewire assembly 20 and the occluding device 100 , carried by the guidewire assembly 20 , have not been introduced into the micro - catheter 1 . instead , as illustrated , they are positioned within the introducer sheath 10 . the introducer sheath 10 may be made from various thermoplastics , e . g ., ptfe , fep , hdpe , peek , etc ., which may optionally be lined on the inner surface of the sheath or an adjacent surface with a hydrophilic material such as pvp or some other plastic coating . additionally , either surface may be coated with various combinations of different materials , depending upon the desired results . the introducer sheath 10 may include drainage ports or purge holes ( not shown ) formed into the wall near the area covering the occluding device 100 . there may be a single hole or multiple holes , e . g ., three holes , formed into introducer sheath 10 . these purge holes allow for fluids , e . g ., saline , to readily escape from in between the introducer sheath 10 and the guidewire assembly 20 when purging the sheath prior to positioning the introducer sheath 10 in contact with the catheter hub 2 , e . g ., to remove trapped air or debris . as shown in fig4 , the guidewire assembly 20 includes an elongated flexible guidewire 21 . the flexibility of the guidewire 21 allows the guidewire assembly 20 to bend and conform to the curvature of the vasculature as needed for positional movement of the occluding device 100 within the vasculature . the guidewire 21 may be made of a conventional guidewire material and have a solid cross section . alternatively , the guidewire 21 can be formed from a hypotube . in either embodiment , the guidewire 21 has a diameter d 5 ranging from about 0 . 010 inch to about 0 . 020 inch . in an embodiment , the largest diameter of the guidewire 21 is about 0 . 016 inch . the material used for the guidewire 21 can be any of the known guidewire materials including superelastic metals , e . g ., nitinol . alternatively , the guidewire 21 can be formed of metals such as stainless steel . length l 4 of the guidewire can be from about 125 to about 190 cm . in an embodiment , the length l 4 is about 175 cm . the guidewire assembly 20 can have the same degree of flexion along its entire length . in an alternative embodiment , the guidewire assembly 20 can have longitudinal sections , each with differing degrees of flexion / stiffness . the different degrees of flexions for the guidewire assembly 20 can be created using different materials and / or thicknesses within different longitudinal sections of the guidewire 21 . in another embodiment , the flexion of the guidewire 21 can be controlled by spaced cuts ( not shown ) formed within the delivery guidewire 21 . these cuts can be longitudinally and / or circumferentially spaced from each other . the cuts can be formed with precision within the delivery guidewire 21 . different sections of the delivery guidewire 21 can include cuts formed with different spacing and different depths to provide these distinct sections with different amounts of flexion and stiffness . in any of the above embodiments , the guidewire assembly 20 and the guidewire 21 are responsive to torque applied to the guidewire assembly 20 by the operator . as discussed below , the torque applied to the guidewire assembly 20 via the guidewire 21 can be used to release the occluding device 100 from the guidewire assembly 20 . the size and shape of the cuts formed within the delivery guidewire 21 may be controlled so as to provide greater or lesser amounts of flexibility . because the cuts can be varied in width without changing the depth or overall shape of the cut , the flexibility of the delivery guidewire 21 may be selectively altered without affecting the torsional strength of the delivery guidewire 21 . thus , the flexibility and torsional strength of the delivery guidewire 21 may be selectively and independently altered . advantageously , longitudinally adjacent pairs of cuts may be rotated about 90 degrees around the circumference of the delivery guidewire 21 from one another to provide flexure laterally and vertically . however , the cuts may be located at predetermined locations to provide preferential flexure in one or more desired directions . of course , the cuts could be randomly formed to allow bending ( flexion ) equally , non - preferentially in all directions or planes . in one embodiment , this could be achieved by circumferentially spacing the cuts . the flexible delivery guidewire 21 can include any number of sections having the same or differing degrees of flexion . for example , the flexible delivery guidewire 21 could include two or more sections . in the embodiment illustrated in fig4 , the flexible delivery guidewire 21 includes three sections , each having a different diameter . each section can have a diameter of about 0 . 005 inch to about 0 . 025 inch . in an embodiment , the diameter of one or more sections can be about 0 . 010 inch to about 0 . 020 inch . a first section 22 includes a proximal end 23 that is located opposite the position of the occluding device 100 . the first section 22 can have a constant thickness along its length . alternatively , the first section 22 can have a thickness ( diameter ) that tapers along its entire length or only a portion of its length . in the tapered embodiment , the thickness ( diameter ) of the first section 22 decreases in the direction of a second , transition section 24 . for those embodiments in which the guidewire 21 has a circular cross section , the thickness is the diameter of the section . the second , transition section 24 extends between the first section 22 and a third , distal section 26 . the second section 24 tapers in thickness from the large diameter of the first section 22 to the smaller diameter of the third section 26 . as with the first section 22 , the second section 24 can taper along its entire length or only a portion of its length . the third section 26 has a smaller thickness compared to the other sections 22 , 24 of the delivery guidewire 21 . the third section 26 extends away from the tapered second section 24 that carries the occluding device 100 . the third section 26 can taper along its entire length from the second section 24 to the distal end 27 of the delivery guidewire 21 . alternatively , the third section 26 can have a constant diameter or taper along only a portion of its length . in such an embodiment , the tapering portion of the third section 26 can extend from the second section 24 or a point spaced from the second section 24 to a point spaced from distal end 27 of the delivery guidewire 21 . although three sections of the delivery guidewire 21 are discussed and illustrated , the delivery guidewire 21 can include more than three sections . additionally , each of these sections can taper in their thickness ( diameter ) along all or only a portion of their length . in any of the disclosed embodiments , the delivery guidewire 21 can be formed of a shape memory alloy such as nitinol . a tip 28 and flexible tip coil 29 are secured to the distal end 27 of the delivery guidewire 21 as shown in fig4 and 5 . the tip 28 can include a continuous end cap or cover as shown in the figures , which securely receives a distal end of the tip coil 29 . flexion control is provided to the distal end portion of the delivery guidewire 21 by the tip coil 29 . however , in an embodiment , the tip 28 can be free of the coil 29 . the tip 28 has a non - percutaneous , atraumatic end face . in the illustrated embodiment , the tip 28 has a rounded face . in alternative embodiments , the tip 28 can have other non - percutaneous shapes that will not injure the vessel in which it is introduced . as illustrated in fig4 , the tip 28 includes a housing 45 that securely receives the distal end of the guidewire 21 within an opening 46 in the interior surface of the housing 45 . the guidewire 21 can be secured within the opening by any known means . as shown in fig4 , the tip coil 29 surrounds a portion of the guidewire 21 . the tip coil 29 is flexible so that it will conform to and follow the path of a vessel within the patient as the tip 28 is advanced along the vessel and the guidewire 21 bends to follow the tortuous path of the vasculature . the tip coil 29 extends rearward from the tip 28 in the direction of the proximal end 23 , as shown . the tip 28 and coil 29 have an outer diameter d 1 of about 0 . 010 inch to about 0 . 018 inch . in an embodiment , their outer diameter d 1 is about 0 . 014 inch . the tip 28 and coil 29 also have a length l 1 of about 0 . 1 cm to about 3 . 0 cm . in an embodiment , they have a total length l 1 of about 1 . 5 cm . a proximal end 30 of the tip coil 29 is received within a housing 32 at a distal end 24 of a protective coil 35 , as shown in fig1 and 4 . the housing 32 and protective coil 35 have an outer diameter d 2 of about 0 . 018 inch to about 0 . 038 inch . in an embodiment , their outer diameter d 2 is about 0 . 024 inch . the housing 32 and protective coil 35 have a length l 2 of about 0 . 05 cm to about 0 . 2 cm . in an embodiment , their total length l 2 is about 0 . 15 cm . the housing 32 has a non - percutaneous , atraumatic shape . for example , as shown in fig5 , the housing 32 has a substantially blunt profile . also , the housing 32 can be sized to open / support the vessel as it passes through it . additionally , the housing 32 can include angled sidewalls sized to just be spaced just off the inner surface of the introducer sheath 10 . the housing 32 and protective coil 35 form a distal retaining member that maintains the position of the occluding device 100 on the flexible guidewire assembly 20 and helps to hold the occluding device 100 in a compressed state prior to its delivery and deployment within a vessel of the vasculature . the protective coil 35 extends from the housing 32 in the direction of the proximal end 23 of the delivery guidewire 21 , as shown in fig4 . the protective coil 35 is secured to the housing 32 in any known manner . in a first embodiment , the protective coil 35 can be secured to the outer surface of the housing 32 . in an alternative embodiment , the protective coil 35 can be secured within an opening of the housing 32 so that the housing 32 surrounds and internally receives the distal end 51 of the protective coil 35 ( fig4 ). as shown in fig3 and 4 , the distal end 102 of the occluding device 100 is retained within the proximal end 52 so that the occluding device 100 cannot deploy while positioned in the sheath 10 or the micro - catheter 1 . at the proximal end of the occluding device 100 , a bumper coil 60 and cap 62 prevent lateral movement of the occluding device 100 along the length of the guidewire 21 in the direction of the proximal end 23 , see fig3 . the bumper coil 60 and cap 62 have an outer diameter d 4 of about 0 . 018 inch to about 0 . 038 inch . in an embodiment , their outer diameter d 4 is about 0 . 024 inch . the cap 62 contacts the proximal end 107 of the occluding device 100 and prevents it from moving along the length of the guidewire 21 away from the protective coil 35 . the bumper coil 60 can be in the form of a spring that contacts and pressures the cap 62 in the direction of the protective coil 35 , thereby creating a biasing force against the occluding device 100 . this biasing force ( pressure ) aids in maintaining the secured , covered relationship between the distal end 102 of the occluding device 100 and the protective coil 35 . as with any of the coils positioned along the delivery guidewire 21 , the bumper coil 60 can be secured to the delivery guidewire 21 by soldering , welding , rf welding , glue , and / or other known adhesives . in an alternative embodiment illustrated in fig1 , the bumper coil 60 is not utilized . instead , a proximal end 107 of the occluding device 100 is held in position by a set of spring loaded arms ( jaws ) 104 while positioned within the introducer sheath 10 or the micro - catheter 1 . the inner surfaces of the micro - catheter 1 and the introducer sheath 10 limit the radial expansion of the arms 104 . when the proximal end of the occluding device passes out of the micro - catheter 1 , the arms 104 would spring open and release the occluding device as shown in fig1 . in an alternative embodiment , the bumper coil 60 and cap 62 can be eliminated and the proximal end of the occluding device 100 can be held in position relative to the protective coil 35 by a tapered section of the guidewire 21 . in such an embodiment , the enlarged cross section of this tapered section can be used to retain the occluding device 100 in position along the length of the delivery guidewire 21 and prevent movement of the occluding device 100 in the direction of the proximal end 23 . as shown in fig4 , the guidewire assembly 20 includes a support 70 for the occluding device 100 . in a first embodiment , the support 70 can include an outer surface of the delivery guidewire 21 that is sized to contact the inner surface of the occluding device 100 when the occluding device 100 is loaded on the guidewire assembly 20 . in this embodiment , the outer surface of the delivery guidewire 21 supports the occluding device 100 and maintains it in a ready to deploy state . in another embodiment , illustrated in the figures , the support 70 comprises a mid - coil 70 that extends from a location proximate the protective coil 35 rearward toward the bumper coil 60 . the mid - coil 70 extends under the occluding device 100 and over the delivery guidewire 21 , as shown in fig1 . the mid - coil 70 can be coextensive with one or more sections of the delivery guidewire 21 . for example , the mid - coil 70 could be coextensive with only the second section 24 of the delivery guidewire 21 or it could extend along portions of both the third section 26 and the second section 24 of the delivery guidewire 21 . the mid - coil 70 provides the guidewire assembly 20 with an outwardly extending surface that is sized to contact the inner surface of the occluding device 100 in order to assist in supporting the occluding device and maintaining the occluding device 100 in a ready to deploy state . like the other coils discussed herein and illustrated in the figures , the coiled form of the mid - coil 70 permits the mid - coil 70 to flex with the delivery guidewire 21 as the delivery guidewire 21 is advanced through the vasculature of the patient . the mid - coil 70 provides a constant diameter along a length of the delivery guidewire 21 that is covered by the occluding device 100 regardless of the taper of the delivery guidewire 21 beneath the occluding device 100 . the mid - coil 70 permits the delivery guidewire 21 to be tapered so it can achieve the needed flexibility to follow the path of the vasculature without compromising the support provided to the occluding device 100 . the mid - coil 70 provides the occluding device 100 with constant support regardless of the taper of the delivery guidewire 21 prior to the occluding device 100 being deployed . the smallest diameter of the occluding device 100 when in its compressed state is also controlled by the size of the mid - coil 70 . additionally , the diameter of the mid - coil 70 can be chosen so that the proper spacing , including no spacing , is established between the occluding device 100 and the inner wall of the micro - catheter 1 prior to deployment of the occluding device 100 . the mid - coil 70 can also be used to bias the occluding device 100 away from the delivery guidewire 21 during its deployment . in either embodiment , the support 70 can have an outer diameter d 3 of about 0 . 010 inch to about 0 . 018 inch . in an embodiment , the outer diameter d 3 is about 0 . 014 inch . the support 70 can also have a length l 3 of about 2 . 0 cm to about 30 cm . in an embodiment , the length l 3 of the support 70 is about 7 cm . the occluding device 100 may also be placed on the mid - coil 70 between an optional pair of radio - opaque marker bands located along the length of the guidewire assembly 20 . alternatively , the protective coil 35 , bumper coil 60 and or mid - coil 70 can include radio - opaque markers . in an alternative embodiment , the guidewire assembly 20 may include only a single radio - opaque marker . the use of radio - opaque markers allows for the visualization of the guidewire assembly 20 and the occluding device 100 during placement within the vasculature . such visualization techniques may include conventional methods such as fluoroscopy , radiography , ultra - sonography , magnetic resonance imaging , etc . the occluding device 100 can be delivered and deployed at the site of an aneurysm a according to the following method and variations thereof . the delivery of the occluding device 100 includes introducing the micro - catheter 1 into the vasculature until it reaches a site that requires treatment . the micro - catheter 1 is introduced into the vasculature using a conventional technique such as being advanced over or simultaneously with a conventional vascular guidewire ( not shown ). the positioning of the micro - catheter 1 can occur before it receives the guidewire assembly 20 or while it contains the guidewire assembly 20 . the position of the micro - catheter 1 within the vasculature can be determined by identifying radio - opaque markers positioned on or in the micro - catheter 1 . after the micro - catheter 1 is positioned at the desired location , the guidewire is removed and the distal end of the introducer sheath 10 is inserted into the proximal end of the micro - catheter 1 , as shown in fig1 . in an embodiment , the distal end of the introducer sheath 10 is introduced through the hub 2 at the proximal end of the micro - catheter 1 . the introducer sheath 10 is advanced within the micro - catheter 1 until a distal tip of the introducer sheath 10 is wedged within the micro - catheter 1 . at this position , the introducer sheath 10 cannot be advanced further within the micro - catheter 1 . the introducer sheath 10 is then securely held while the delivery guidewire assembly 20 carrying the occluding device 100 is advanced through the introducer sheath 10 until the occluding device 100 is advanced out of the introducer sheath 10 and into the micro - catheter 1 . the guidewire assembly 20 and the occluding device 100 are advanced through the micro - catheter 1 until the tip coil 29 is proximate the distal end of the micro - catheter 1 . at this point , the position of the micro - catheter 1 and guidewire assembly 20 can be confirmed . the guidewire assembly 20 is then advanced out of the micro - catheter 1 and into the vasculature of the patient so that the proximal end 107 of the occluding device 100 is positioned outside the distal end of the micro - catheter 1 and adjacent the area to be treated . at any point during these steps , the position of the occluding device 100 can be checked to determine that it will be deployed correctly and at the desired location . this can be accomplished by using the radio - opaque markers discussed above . when the distal end 102 of the occluding device 100 is positioned outside the micro - catheter 1 , the proximal end 107 will begin to expand , in the direction of the arrows shown in fig7 , within the vasculature while the distal end 102 remains covered by the protective coil 35 . when the occluding device 100 is in the proper position , the delivery guidewire 21 is rotated ( see fig8 ) until the distal end 102 of the occluding device 100 moves away from the protective coil 35 and expands within the vasculature at the desired location . the delivery guidewire 21 can be rotated either clockwise or counter clockwise as needed to deploy the occluding device 100 . in an embodiment , the delivery guidewire 21 may be rotated , for example , between two and ten turns in either or both directions . in another example , the occluding device may be deployed by rotating the delivery guidewire 21 clockwise for less than five turns , for example , three to five turns . after the occluding device 100 has been deployed , the delivery guidewire 21 can be retracted into the micro - catheter 100 and removed form the body . in an alternative or additional deployment step shown in fig9 , friction between the occluding device 100 and inner surface of the micro - catheter 1 cause the distal end of the occluding device 100 to separate from the protective coil 35 . the friction can be created by the opening of the occluding device 100 and / or the mid - coil 70 biasing the occluding device 100 toward the inner surface of the micro - catheter 1 . the friction between the micro - catheter 1 and the occluding device 100 will assist in the deployment of the occluding device 100 . in those instances when the occluding device 100 does not open and separate from the protective coil 35 during deployment , the friction between occluding device 100 and the inner surface of the micro - catheter 1 will cause the occluding device 100 to move away from the protective coil 35 as the delivery guidewire 21 and the micro - catheter 1 move relative to each other . the delivery guidewire 21 can then be rotated and the occluding device 100 deployed within the vessel . after the occluding device 100 radially self - expands into gentle , but secure , contact with the walls of the vessel so as to occlude the neck of the aneurysm a , the micro - catheter 1 may be removed entirely from the body of the patient . alternatively , the micro - catheter 1 may be left in position within vasculature to allow for the insertion of additional tools or the application of drugs near the treatment site . known materials can be used in the present invention . one common material that can be used with the occluding device 100 and the guidewire 21 is nitinol , a nickel - titanium shape memory alloy , which can be formed and annealed , deformed at a low temperature , and recalled to its original shape with heating , such as when deployed at body temperature in the body . the radio - opaque markers can be formed of radio - opaque materials including metals , such as platinum , or doped plastics including bismuth or tungsten to aid in visualization . the apparatus and methods discussed herein are not limited to the deployment and use within the vascular system but may include any number of further treatment applications . other treatment sites may include areas or regions of the body such as organ bodies . modification of each of the above - described apparatus and methods for carrying out the invention , and variations of aspects of the invention that are obvious to those of skill in the art are intended to be within the scope of the claims . furthermore , no element , component or method step is intended to be dedicated to the public regardless of whether the element , component or method step is explicitly recited in the claims .
a system and method for deploying an occluding device that can be used to remodel an aneurysm within the vessel by , for example , neck reconstruction or balloon remodeling . the system comprises an introducer sheath and an assembly for carrying the occluding device . the assembly includes an elongated flexible member having an occluding device retaining member for receiving a first end of the occluding device , a proximally positioned retaining member for engaging a second end of the occluding device and a support surrounding a portion of the elongated flexible member over which the occluding device can be positioned .