US20020099408A1 - Method and apparatus for detaching an intracorporeal occlusive device - Google Patents

Abstract

An intracorporeal space filling device and a delivery system and method for using the device is disclosed. The space filling device is preferably configured for percutaneous delivery from a peripheral conduit of a patient. The space filling device has an elongated tubular or interconnected bead structure which may have a transmutable material disposed within it. The transmutable material can be altered from a non-rigid state to a rigid state by the application of various types of energy or by other suitable means. The space filling device can be positioned by a delivery system and detached from the delivery system after desired positioning is achieved.

Description

• This is a divisional application of U.S. patent application Ser. No. 09/324,987 filed Jun. 2, 1999, the disclosure of which is incorporated in its entirety herein by reference.[0001]
BACKGROUND
• The present invention is generally directed to occlusion devices and, more specifically, to intracorporeal occlusion devices which can be used to treat a patient's blood vessels, intracorporeal conduits or other portions of a patient's body. A preferred embodiment can be used to treat intracranial aneurysms, arteriovenous fistulas, and other abnormalities within the cerebral vasculature.[0002]
• Cerebral aneurysms and other cerebral vascular abnormalities present a significant medical problem to the population of the United States. It is estimated that the number of ruptured intracranial aneurysms yearly is in the tens of thousands, often with devastating consequences for the patient. For a patient who has been diagnosed with a cerebral aneurysm, there are a few treatment modalities currently available. An invasive surgical treatment can be used where access to the external portion of the aneurysm is achieved by placing the patient under general anesthesia, performing a craniotomy, and brain tissue retraction. Once access has been gained to the external surface of the aneurysm, the neck of the aneurysm can be clipped. Clipping the aneurysm neck prevents the ingress of blood into the aneurysm cavity which can lead to rupture. Because of the invasive nature of the procedure and the vulnerability of the brain tissue surrounding the aneurysm, this procedure carries a high degree of risk with concomitant mortality and morbidity rates. This risk is particularly high when the aneurysm has ruptured prior to the surgical intervention.[0003]
• An alternative to the surgical method currently in use involves percutaneous endovascular intervention. This method generally involves accessing the cerebral aneurysm by means of an intravascular microcatheter which is advanced under flouroscopic imaging over a guidewire or the like within the patient's arteries from a puncture site in the patient's leg or arm. The distal end of the microcatheter is guided over a guidewire within a patient's vasculature and disposed adjacent the neck of the aneurysm. The distal tip of the microcatheter can then be directed into the cavity of the aneurysm and appropriate occlusive devices then delivered from a port in the distal end of the microcatheter. Presently, the most common occlusive device delivered via microcatheter is a vaso-occlusive coil which consists of stainless steel or radiopaque metals such as gold or platinum, tantalum. The vaso-occlusive coils are typically manufactured in a manner similar to the distal coils of a coronary guidewire, having a coil wire material with a small diameter and a coil outer diameter suitable for delivery through a microcatheter. Such vaso-occlusive coils are often given a secondary shape or configuration whereby the coils can be straightened and delivered through the inner lumen of a microcatheter, but form a convoluted or random space filling structure once delivered from the distal end of the microcatheter. The endovascular delivery of vaso-occlusive coils through a microcatheter represents a significant advance in treating cranial aneurysms. However, the coils are hollow bodies, often made of relatively soft metals which are subject to compaction due to the pressure exerted on the deployed coils by the patient's blood flow. Compaction and reforming of the coils leaves them susceptible to dislodging and being displaced within the patient's vasculature, with the potential for causing distal embolization. In addition, compaction of the coils into the dome of the aneurysm or blood clot surrounding the coils can lead to reappearance and regrowth of the aneurysm. Finally, aneurysms with wide necks having a dome to neck dimension ratio of less than 2 to 1 often do not provide a morphology conducive to retention of coils within the aneurysm. Thus currently available coils are generally contraindicated for use in wide neck aneurysms. What has been needed is an intracorporeal space filling device which can be delivered by non-invasive methods, is not subject to compaction or reforming and which is suitable for implantation in wide neck aneurysms.[0004]
SUMMARY
• The invention is directed generally to an intracorporeal space filling device and a delivery system for positioning and deploying the space filling device within a patient. The invention is also directed to a method for using the space filling device.[0005]
• One preferred embodiment of the invention is an intracorporeal space filling device which has an elongate tubular shell with a lumen disposed within the shell. The lumen is in fluid communication with a first port in a first end of the shell, and a second port in a second end of the shell. A transmutable material is disposed within the lumen of the shell substantially filling the lumen. The transmutable material has properties which enable transformation from a non-rigid state to a substantially rigid state within a patient's body. The transmutable character of the transmutable material allows for a space filling device that is soft and flexible at the time of deployment into an intracorporeal cavity and rigid and substantially incompressible after being converted to a rigid state. Such a device can conform readily to the varied morphology of intracorporeal cavities and transmute to a substantially rigid mass upon activation or hardening of the transmutable material so as to be resistant to compression and reforming due to vascular or other types of pressures within a patient's body.[0006]
• The elongate shell is generally made of a polymeric wall material and is sealed at either or both of the first and second ends. The transmutable material which fills the lumen of the shell can be selected from a variety of suitable polymers which can be made rigid or hardened by the application of a variety of energy types, such as light emitted from a laser or other source, radiofrequency energy, ultrasonic energy or other suitable means such as controlled changes in the pH of the material surrounding the transmutable material. The space filling device is typically configured for percutaneous delivery through a suitable microcatheter from an incision in a peripheral artery in a patient's arm or leg to a desired intracorporeal cavity, such as a cerebral aneurysm.[0007]
• Optionally, the space filling device may have an elongated longitudinal member secured to and preferably coextensive with the elongate tubular shell of the device. Typically, the elongated longitudinal member is a thin wire member that may or may not be configured to give a secondary shape to the space filling device when in an unconstrained relaxed state. The secondary shape of the longitudinal member can be a convoluted, folded, coiled or twisted configuration or any other suitable space filling configuration when in an unconstrained state which is imparted to the intracorporeal space filling device to which the elongated longitudinal member is secured. When the device is in a linear constrained state or configuration, it may be advanced through an inner lumen of a microcatheter or other similar device for delivery to a desired site within a patient's body. Once the space filling device is removed from the constraint of the microcatheter, it again assumes the space filling secondary shape. The elongated longitudinal member can be made from a variety of suitable materials, including stainless steel and shape memory alloys such as nickel titanium (NiTi). The elongated longitudinal member can be disposed along a longitudinal axis of the space filling device, embedded in the transmutable material, encapsulated within the wall material of the elongate tubular shell, or adjacent an outside surface of the elongate tubular shell or any other suitable location on the device. Preferably the elongate longitudinal member is substantially parallel to the longitudinal axis of the elongate shell or intracorporeal space filling device. The elongated longitudinal member can also be configured to be heated by the passage of various types of energy therethrough. For example, an elongated longitudinal member made of NiTi alloy can be configured to be heated by the passage of electrical current, including radiofrequency, or ultrasonic energy through it. Heating of the elongated longitudinal member can be used to transmute or rigidify the transmutable material within the elongate shell and to act as a mechanism for detachment of the intracorporeal space filling device from the distal end of the delivery system.[0008]
• In a preferred embodiment, the elongate tubular shell is configured to have an outer surface which is self adhering to create attachment points from contact point upon activation of the self adhering outer surface. Contact points along the length of the space filling device inevitably occur when the device is deployed within an intracorporeal cavity or channel and the space filling device assumes a folded or convoluted space filling configuration. The folded or convoluted space filling configuration may be due to the confinement of the void or channel, a secondary shape assumed by the device in a relaxed state, or both. The creation of attachment points results in a more rigid and stable space filling mass that is resistant to compaction and reforming.[0009]
• The intracorporeal space filling device may optionally have a helical coil disposed about an outer surface of the elongate tubular shell. The helical coil may have properties similar to those discussed above with regard to the elongated longitudinal member. For example, the helical coil can be configured to impose a convoluted, folded or space filling secondary shape on the space filling device when in a relaxed unconstrained state. The helical coil may also be configured to heat or otherwise activate transmutation of the transmutable material when various forms of energy are passed through it such as electrical current, ultrasonic energy or the like. The materials of the helical coil may also be similar to those discussed above with regard to the elongated longitudinal member.[0010]
• In an alternative embodiment, the space filling device has a transmutable material disposed about an elongated longitudinal member without an outer shell so that the transmutable material is exposed when the device is deployed within a patient's body. The elongated longitudinal member can have properties similar to those of the elongated longitudinal members discussed above. For example, the elongated longitudinal member can be made of a thin wire with a secondary shape. The secondary shape can be imparted on the space filling device when the device is in an unconstrained state. Secondary shapes can include convoluted or folded space filling configurations. Exposure of an outside surface of the transmutable material allows the transmutable material to adhere to itself upon transmutation at attachment points where different portions of the space filling device make contact due to the secondary shape assumed. When the space filling device is deployed in an intracorporeal cavity and assumes a folded, bunched or convoluted configuration due to a secondary shape of the elongated longitudinal member or the natural confinement of the cavity, inevitably, certain portions of the space filling device will make physical contact with other portions of the device. As such, the transmutable material of these portions will make contact at contact points and will cross-link, bond, or self adhere to each other to form attachment points upon transmutation of the transmutable material. The cross-linking or bonding of the device at attachment points results in a rigid mass which is resistive to compression and reforming. The self adhering property of the outside surface of the transmutable material can be as a result of the intrinsic properties of the transmutable material, or as a result of a coating applied to the transmutable material with self adhering properties.[0011]
• In another embodiment, the intracorporeal space filling device has a plurality of beads connected to at least one adjacent bead by a flexible member with connections to adjacent beads being configured to produce a linear array of the beads. Each bead has a transverse dimension and is generally spaced within one transverse dimension of adjacent beads, however, other appropriate spacings are possible. The space filling device of interconnected beads is generally configured for percutaneous delivery through a microcatheter or the like from an incision in a peripheral artery of a patient to a desired cavity within the patient's vasculature such as a cerebral aneurysm. The individual beads typically have a generally spherical shape, but can also be substantially elliptical or elongated. The beads can be made from any suitable material, but are preferably made from a polymer material, and more preferably a transmutable polymer material. In a particular embodiment, the beads may have an outer shell which defines a cavity which optionally contains suitable filler material. Suitable filler materials include biocompatible fluids such as a saline, silicone and the like, and polymers such as a transmutable material similar to the transmutable material discussed above.[0012]
• Embodiments with beads of exposed transmutable material can be cross-linked or bonded to adjacent beads which are in contact at the time of transmutation at a desired site within a patient's body. Adjacent beads in contact while deployed within a desired location within a patient can adhere or bond together and create attachment points upon transmutation of the transmutable material. The attachment points create a more stable and rigid mass than would be achieved by transmutation of the beads without attachment points.[0013]
• The flexible member connecting adjacent beads may consist of interconnected portions of a polymer wall material of the outer shell of each adjacent bead. The flexible member may also be an elongated longitudinal member disposed substantially along a longitudinal axis of the space filling device and being substantially coextensive with at least two adjacent beads of the space filling device. In embodiments of the space filling device having a flexible member consisting of an elongated longitudinal member, the elongated longitudinal member may be a thin wire, preferably of a shape memory alloy. The thin wire longitudinal member can be configured to be heated by a passage of energy through it in order to activate transmutation of transmutable material disposed thereon. The elongated longitudinal member may also be configured to have a secondary shape or space filling configuration in a relaxed state as discussed above with regard to other elongated longitudinal members. The secondary shape or space filling configuration of the elongated longitudinal member would be imparted to the space filling device as a whole when in an unconstrained relaxed state.[0014]
• The intracorporeal space filling devices discussed above are generally deployed at a desired site within a patient's body by disposing the distal end of a microcatheter or the like such that a distal port in the distal end of the microcatheter is directed to a desired cavity or channel within a patient. The space filling device is then distally advanced within the inner lumen of the microcatheter, preferably by means of a delivery system which has an elongate shaft with a detachment mechanism disposed on the distal end of the system. The detachment mechanism is detachably secured to a first end of the space filling device which provides a detachable connection and allows for remote advancement and retraction of the space filling device within the patient prior to detachment. The space filling device is then distally advanced out of a port in the distal end of the microcatheter and into the cavity or channel of the patient. When the space filling device is appropriately positioned, the transmutable material within the device is activated so as to be hardened or rigidified, and the device detached from the delivery system. Preferably, the space filling device is detached by a detachment mechanism utilizing degradation of a polymer link between the delivery system and the first end of the space filling device. Degradation of the polymer link may be accomplished by a chain cleavage reaction which can be initiated by heating of the polymer link. Alternative detachment mechanisms include mechanical detachment, electrolytic detachment, detachment by shape memory alloy or shape memory polymer activation via application of RF energy, laser energy or ultrasonic energy, heating of a hot melt adhesive joint, ultrasonic link degradation, hydrokinetic pressure activation of a mechanical retention device, and the like.[0015]
• During deployment of a space filling device, a blocking balloon may be deployed adjacent the opening of an intracorporeal void and distal end of a microcatheter disposed within the void prior to distally advancing the space filling device from the distal end of the microcatheter into the cavity. The blocking balloon prevents egress of the space filling device from within the cavity during deployment of the device.[0016]
• These and other advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying exemplary drawings.[0017]
BRIEF DESCRIPTION
• FIG. 1 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0018]
• FIG. 2 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 1 taken at[0019]lines2—2 of FIG. 1.
• FIG. 3 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0020]
• FIG. 4 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 3 taken at[0021]lines4—4 of FIG. 3.
• FIG. 5 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0022]
• FIG. 6 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 5 taken at[0023]lines6—6 of FIG. 5.
• FIG. 7 is a longitudinal sectional view in of an intracorporeal space filling device similar to the device of FIG. 1, but including an outer coil member.[0024]
• FIG. 8 is a transverse cross sectional view of the device of FIG. 7 taken along[0025]lines8—8 in FIG. 7.
• FIG. 9 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0026]
• FIG. 10 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 9 taken at[0027]lines10—10 of FIG. 9.
• FIG. 11 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 9 taken at[0028]lines11—11 of FIG. 9.
• FIG. 12 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0029]
• FIG. 13 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 12 taken at[0030]lines13—13 of FIG. 12.
• FIG. 14 is a longitudinal sectional view of an intracorporeal space filling device having features of the invention.[0031]
• FIG. 15 is a transverse cross sectional view of the intracorporeal space filling device of FIG. 14 taken at[0032]lines15—15 of FIG. 14.
• FIG. 16 is a schematic view in partial longitudinal section of a microcatheter over a guidewire disposed within a patient's blood vessel.[0033]
• FIG. 17 is a schematic view in partial section of the distal end of a microcatheter disposed within the neck of an aneurysm.[0034]
• FIG. 18 is a schematic view in partial section of the distal end of a microcatheter disposed within an aneurysmal cavity with an intracorporeal space filling device deployed within the aneurysm.[0035]
• FIG. 19 is a schematic view in partial section of a blocking balloon deployed adjacent an aneurysm with the distal end of a microcatheter disposed within the aneurysm and an intracorporeal space filling device disposed within the aneurysm.[0036]
• FIG. 20 is an elevational view in partial section of a first end of an intracorporeal space filling device detachably secured to a distal end of a deliver system having features of the invention.[0037]
• FIG. 21 is an elevational view in partial section of a first end of an intracorporeal space filling device detachably secured to a distal end of a delivery system having features of the invention.[0038]
• FIG. 22 is an elevational view in partial section of a first end of an intracorporeal space filling device detachably secured to a distal end of a delivery system having features of the invention.[0039]
• FIG. 23 is an elevational view in partial section of a first end of an intracorporeal space filling device detachably secured to a distal end of a delivery system having features of the invention.[0040]
• FIGS. 24-26 depict an alternative embodiment of a capture element for detachment of the space filling device.[0041]
DETAILED DESCRIPTION
• FIG. 1 illustrates an intracorporeal[0042]space filling device10 having features of the invention. The intracorporealspace filling device10 has an optional elongatetubular shell11 with afirst end12 and asecond end13, the elongate shell being formed of awall material14. There is alumen15 disposed within the elongatetubular shell11 which hastransmutable material16 disposed therein.
• The elongate[0043]tubular shell11 can be made from a variety of materials including metals and polymers. Suitable metals for the elongate tubular shell include stainless steel, NiTi, gold, platinum, tantalum, palladium, alloys thereof and the like. If a metal or other rigid material is used, methods such as forming slots or grooves in the wall material of such an elongate tubular shell may be used to achieve a desired longitudinal flexibility of the elongatetubular shell11. Suitable polymers for the elongatetubular shell11 can include polyurethane, polyethylene, nylon, polyimide, polyamide, polytetraflouroethylene, polyester, polypropylene and the like. The elongatetubular shell11 may be sealed and impermeable to thetransmutable material16, so as to prevent the egress of the transmutable material from within the shell to the surrounding environment.
• In one preferred embodiment, the elongate[0044]tubular shell11 has at least one aperture which exposes thetransmutable material16 and allows the transmutable material to make contact with adjacent portions of the space filling device or other space filling devices so as to permit self adhering or bonding upon transmutation of the transmutable material. The apertures in the elongatetubular shell11 can be in the form of transverse or longitudinal slots or grooves, circular or otherwise configured holes, or the like. The apertures may be relatively far apart relative to the size of the apertures, or they may be relatively close together and numerous so as to form a mesh pattern or other suitable pattern of fenestration which facilitates exposure of thetransmutable material16 but maintains the overall elongated structure of thespace filling device10. Similar apertures may be appropriate for any of the various embodiments of space filling devices discussed herein having outer shell structures.
• The dimensions of the[0045]space filling device10 and elongatetubular shell11 are generally appropriate for percutaneous delivery via a microcatheter to a desired site within a patient's vasculature, however, other suitable dimensions and configurations are contemplated. The length of thespace filling device10, and all other embodiments of space filling devices discussed herein generally, can be from about 0.5 to about 50 cm, preferably about 2 to about 30 cm. It should be noted that the morphology of the sites being filled or otherwise treated by the present invention vary greatly. Embodiments of the invention for use treating cerebral aneurysms may be made available in a variety of sizes and lengths so that most of the anticipated morphologies can be accommodated. For example, aspace filling device10, and other space filling devices discussed herein generally, configured for treatment of cerebral aneurysms, or the like, may be made available in lengths of 2, 5, 10, 15, 20, 25, 30, 35 and 40 cm. In this way, a wide range of aneurysm volumes can be appropriately treated.
• A transverse dimension of the[0046]space filling device10, and of all other embodiments of space filling device discussed herein generally, can be from about 0.005 to about 0.25 inches, preferably about 0.01 to about 0.038 inches, and more preferably about 0.014 to about 0.018 inches. In other preferred embodiments of the invention, the transverse dimension of the space filling device can be from about 0.004 to about 0.02 inches, preferably about 0.008 to about 0.012 inches. The thickness of thewall material14 of the elongatetubular shell11 can be from about 0.0001 to about 0.01 inches, preferably about 0.0005 to about 0.002 inches, and more preferably about 0.001 to about 0.0015 inches.
• The[0047]transmutable material16 disposed within the elongatetubular shell11 is preferably a material that can be transmuted by polymerization, crystallization or other suitable process from a non-rigid liquid, gel or granular state to a rigid state. Some of the materials suitable for this application are discussed generally in U.S. Pat. No. 5,334,201, K. Cowan, and U.S. Pat. No. 5,443,495, P. Buscemi, et al., which are hereby incorporated by reference in their entirety. Transmutation of the transmutable material can be achieved or activated by the application of a suitable type of energy to the transmutable material. Suitable types of energy include electromagnetic energy in the form of light, DC current, AC current, RF current or the like in addition to ultrasonic energy. Energy may also be applied directly or indirectly in the form of heat to cause transmutation. Transmutation may also be activated by altering the chemistry of the environment surrounding the transmutable material such as by changing the pH or by injection of a catalyst into the transmutable materials, either directly or indirectly by injection or introduction into the surrounding tissue or bodily fluid such a blood. With regard to the embodiment of FIG. 1, laser or RF energy is preferably applied to the outer surface of the elongate tubular shell and transmutable material to cause transmutation. The outer dimensions of thetransmutable material16 are generally similar to the cavity dimensions of the elongatetubular shell11. As an alternative to thetransmutable material16, any suitable biocompatible filler material may be used such as saline, silicone or the like. Such alternative filler materials may be used within any of the suitable embodiments of space filling devices described herein, either as an alternative to a transmutable material, or in addition to a transmutable material. Embodiments of the invention suitable for alternative filler materials are generally those embodiments having a shell structure configured to confine the alternative filler materials.
• In embodiments of the[0048]space filling device10 where thetransmutable material16 is exposed, that is, where the optional elongatetubular shell11 is not present, or portions of the elongatetubular shell11 are not present at aperture sites, it is preferable that thetransmutable material16 be self adhering in a fluid field, such as blood or saline. In this way, when thedevice10 is deployed within an intracorporeal cavity or channel and folds back on itself as a result of the confinement of the cavity or channel, any contact points between transmutable material where the device is folded on itself and making mechanical contact will become attachment points upon transmutation of the transmutable material by bonding or adhering to itself at the contact points. The attachment points result in a more stable space filling mass that is resistant to compaction and reforming.
• Suitable substances generally for the[0049]transmutable material16 include methacrylate compounds, linear polyester, silicone, cyanoacrylates, polyisocyanate, u.v. curable acrylates, moisture cure silicones, dimethyl sulfoxide, thioisocyanate aldehyde, isocyanate, divinyl compounds, epoxide acrylates, succinimidyl azido salicylate, succinimidyl azidobenzoate, succinimidyl dithio acetate, azidoiodobenzene, flouronitrophenylazide, salicylate azides, benzophenonemaleimide, and the like.
• FIG. 2 is a transverse cross sectional view of the intracorporeal[0050]space filling device10 of FIG. 1. Thetransmutable material16 is disposed within the optional elongatetubular shell11 of the device. The cross section of FIG. 2 is shown as substantially round, however, other suitable cross sectional configurations can be used such as elliptical, triangular or square.
• FIGS. 3 and 4 illustrate an intracorporeal[0051]space filling device20 similar to the embodiment of FIG. 1, with the addition of an elongatedlongitudinal member21 disposed along a longitudinal axis22 of the optional elongatetubular shell23. The materials, dimensions, and features of the elongatedtubular shell23 of FIGS. 3 and 4 can be similar to those of the elongatedtubular shell11 of FIGS. 1 and 2. The materials, and dimensions of thetransmutable material24 can be similar to those of thetransmutable material16 discussed above. Typically, the elongatedlongitudinal member21 is a thin wire member that is configured to give a secondary shape to the space filling device when in an unconstrained relaxed state. Thelongitudinal member21 can have a secondary shape of a convoluted, folded, coiled or twisted configuration or any other suitable space filling configuration when in an unconstrained state. This configuration is imparted to the intracorporealspace filling device20 to which the elongatedlongitudinal member21 is secured. When thedevice20 is in a linear constrained state or configuration, it may be advanced through an inner lumen of a microcatheter or other similar device for delivery to a desired site within a patient's body. Once thespace filling device20 is removed from the constraint of the microcatheter, it again assumes the space filling configuration. Thespace filling device20, and all other space filling devices described herein generally which are configured to have a secondary space filling shape, may have a variety of nominal transverse dimensions or diameters when in a secondary shape. In order to conform to a wide variety of intracorporeal morphologies, the space filling device may have a secondary shape with a transverse dimension of between about 1 to about 20 mm. A typical space filling device maybe made with a secondary shape having a transverse dimension of between 1 and 20 mm, in 1 mm increments.
• The elongated[0052]longitudinal member21 can be made from a variety of suitable materials, including stainless steel and shape memory alloys such as nickel titanium (NiTi). The length of the elongatedlongitudinal member21 can be from about 0.5 to about 50 cm, preferably about 1 to about 20 cm, and more preferably about 5 to about 15 cm. It is preferable that the elongatedlongitudinal member21 be coextensive with the length of the elongatedtubular shell23 and with the space filling device generally. Thus, the elongated longitudinal member may have any of the lengths discussed herein with regard to space filling devices. The transverse dimension of the elongatedlongitudinal member21 can be from about 0.0005 to about 0.01 inches, preferably about 0.001 to about 0.003 inches, and more preferably about 0.0015 to about 0.002 inches. The cross section of the elongated longitudinal member is generally round, however, other configurations are contemplated. Alternative cross sectional shapes for the elongated longitudinal member include elliptical, rectangular, as would be found if a flat ribbon wire used, triangular, square and the like. The various cross sections can be chosen to give a desired preferred bend axis or axes along the length of the member. Preferably the elongate longitudinal member is substantially parallel to the longitudinal axis22 of the elongate shell or intracorporeal space filling device. The elongatedlongitudinal member21 can also be configured to be heated by the passage of various types of energy therethrough. For example, an elongatedlongitudinal member21 made of NiTi alloy can be configured to be heated by the passage of electrical current through it. Heating of the elongatedlongitudinal member21 can be used to transmute or rigidify the transmutable material within the elongatetubular shell23 and to act as a mechanism for detachment of the intracorporealspace filling device20 from a distal end of a delivery system.
• FIGS. 5 and 6 show an embodiment of an intracorporeal space filling device[0053]30 similar to the embodiment of FIGS. 3 and 4 but having an elongatedlongitudinal member31 encapsulated within awall material32 of the elongatedtubular shell33. The materials, dimensions and features of the elongatedtubular shell33 and elongatedlongitudinal member31 of FIGS. 5 and 6 are similar to those of the elongatedtubular shell23 and elongatedlongitudinal member21 of FIGS. 3 and 4. The elongatedlongitudinal member31 may also be secured to anoutside surface34 or insidesurface36 of the elongatetubular shell33 by an adhesive or other suitable means. Atransmutable material35 disposed within the elongatetubular shell33 can have properties and dimensions similar to or the same as those oftransmutable materials16 and24 of FIGS. 1-4 above.
• FIGS. 7 and 8 illustrate an intracorporeal space filling device[0054]40 similar to that of FIGS. 1 and 2, but with ahelical coil41 disposed about anoutside surface42 of the elongatedtubular shell43. Thehelical coil41 of FIGS. 7 and 8 may have some properties similar to those discussed above with regard to the elongatedlongitudinal members21 and31 of FIGS. 3-6. Thehelical coil41 can be configured to impose a convoluted, folded or space filling configuration on the space filling device40 when in a relaxed unconstrained state. Thehelical coil41 may also be configured to heat when various forms of energy are passed through it. The materials of thehelical coil41 can be any suitable metal, composite or polymer including shape memory alloys such as NiTi or high strength alloys such as stainless steel. The type and dimensions of the material from which thehelical coil41 is made can be similar to the elongatedlongitudinal member31 discussed above. Atransmutable material44 is disposed within the elongatedtubular shell43 and can have properties similar or identical to the properties oftransmutable materials16,24 and35 of FIGS. 1-6 above.
• FIGS. 9-11 depict an alternative embodiment of an intracorporeal space filling device[0055]50 having a plurality ofbeads51 secured to each other in a linear configuration. The intracorporeal space filling device50 has a plurality ofbeads51 connected to at least one adjacent bead by aflexible member52 with connections to adjacent beads preferably being configured to produce a linear array of the beads. Eachbead51 has a transverse dimension and is generally spaced within one transverse dimension of adjacent beads, however, other appropriate spacings are possible. The space filling device50 is generally configured for percutaneous delivery through a microcatheter or the like from an incision in a peripheral artery of a patient to a desired cavity within the patient's vasculature such as a cerebral aneurysm. Theindividual beads51 typically have a generally spherical shape, but can also be substantially elliptical, with the elliptical shape optionally being elongated longitudinally to a length of multiple transverse dimensions. Thebeads51 can be made from a rigid homogeneous polymer material, but are preferably made from anouter shell53 which defines acavity54 such as is shown in FIGS. 9-11. Theouter shell53 can be made from a variety of materials including metals and polymers. Suitable metals for theshell53 include stainless steel, NiTi, gold, platinum, tantalum, palladium, alloys thereof and the like. If a metal or other rigid material is used, methods such as forming slots or grooves in the wall material of the shell may be used to achieve a desired longitudinal flexibility. Suitable polymers for theshell53 can include polyurethane, polyethylene, nylon, polyimide, polyamide, polytetraflouroethylene, polyester, polypropylene and the like. Theouter shell53 may have apertures similar to those ofspace filling device10 described above for exposing portions of transmutable material contained therein which facilitates self adherence and the creation of attachment points upon transmutation of the transmutable material.
• The[0056]cavity54 optionally contains atransmutable material55 similar to thetransmutable materials16,24,35 and44 discussed above. Thetransmutable material55 is preferably a material that can be transmuted by polymerization, crystallization or other suitable process from a non-rigid liquid, gel or granular state to a rigid state. Transmutation of thetransmutable material55 can be achieved or precipitated by the application of a suitable type of energy to the transmutable material such as electromagnetic energy in the form of light, DC current, AC current, RF or ultrasonic energy. Energy may also be applied directly or indirectly in the form of heat to cause transmutation. Other methods of causing or precipitating transmutation can include altering the pH of the surrounding environment of the transmutable material, or injecting a catalyst into the transmutable material directly, or indirectly by injecting a catalyst into the environment of the transmutable material.
• The dimensions of the space filling device[0057]50 overall are similar to those of the previously discussed embodiments. The thickness of thewall material56 of theouter shell53 can be from about 0.0001 to about 0.01 inches, preferably about 0.0005 to about 0.002 inches, and more preferably about 0.001 to about 0.0015 inches. Thewall material56 of theouter shell53 of thebeads51 and thetransmutable material55 disposed within the outer shell can be similar to the materials of the elongatetubular shell11 andtransmutable material16 of the embodiment of FIG. 1.
• The[0058]flexible member52 connecting adjacent beads may consist of interconnected portions of apolymer wall material56 of theouter shell53 of each adjacent bead as shown in FIGS. 9-11. As shown in FIGS. 12-13, an intracorporealspace filling device60 may have flexible members61 that consist of portions of an elongatedlongitudinal member62 disposed substantially along alongitudinal axis63 of thespace filling device60 and being substantially coextensive with at least twoadjacent beads64 of the space filling device. Thebeads64 of thespace filling device60 are made of apolymer material65 which is a transmutable material. The exposed outer surface of the transmutable material of thebeads64 is self adhering in a fluid-field, such as blood or saline. When thespace filling device60 is deployed within a body cavity and folds back on itself as a result of the confinement or secondary shape, any contact points where the device is folded on itself making mechanical contact will become attachment points upon transmutation of the transmutable material of thebeads64. The attachment points result in a more stable space filling mass which is resistant to compaction and reforming.
• The elongated[0059]longitudinal member62 may be a thin wire, preferably of a shape memory alloy that can be configured to be heated by a passage of energy through it. The elongatedlongitudinal member62 shown in FIGS. 12-13 can have similar dimensions and properties to the elongatedlongitudinal members21 and31 shown in FIGS. 3-6. These properties can include a secondary shape, shape memory properties, and heating upon a passage of energy through the elongatelongitudinal member62. In addition, the elongatedlongitudinal member62 can have a variety of cross section configuration including round, square, rectangular and the like.
• FIGS. 14 and 15 depict an intracorporeal space filling device[0060]66 which hasbeads67 attached in a substantially linear array by an elongate longitudinal member68. Thebeads67 have anouter shell69 which is optionally filled with atransmutable material69A. The dimensions and materials ofbeads67 can be similar to those ofbeads51 discussed above with regard to FIGS. 9-11. The materials and dimensions of longitudinal member68 can be similar to those of elongatedlongitudinal member62 discussed above with respect to FIGS. 12 and 13.
• FIGS. 16-19 schematically depict a procedure whereby an intracorporeal[0061]space filling device70 is deployed within an intravascularcerebral aneurysm71 of a patient by percutaneous means through alumen72 of amicrocatheter73. Thedistal end74 ofmicrocatheter73 is advanced over aguidewire75 through a patient's vasculature andartery76 to ananeurysm71. Thespace filling device70 is then distally advanced within aninner lumen72 of themicrocatheter73, preferably by means of a delivery system77. Delivery system77 has an elongate shaft80 with a detachment mechanism81 disposed on thedistal end82 of the system. The detachment mechanism81 is detachably secured to a first end83 of thespace filling device70 which allows proximal manipulation of the delivery system77 to control axial advancement and retraction of the space filling device within themicrocatheter73 and the patient. Thespace filling device70 is then distally advanced out of aport84 in thedistal end74 of themicrocatheter73 and into theaneurysm71.
• When the[0062]space filling device70 is appropriately positioned, transmutable material ofdevice70 is transmuted to a rigid state, and thespace filling device70 detached from the delivery system77. Transmutation of the transmutable material may take place prior to, during or after detachment of the space filling device from the detachment mechanism. Thespace filling device70 is detached by degradation of apolymer link85 between thedelivery system70 and the first end83 of the space filling device, preferably by a chain cleavage reaction which can be initiated by heating of thepolymer link85. Although the illustrated method of detachment of thespace filling device70 is chain cleavage degradation of apolymer link85, any suitable detachment method may be used. Examples of suitable detachment methods include mechanical detachment, electrolytic detachment, shape memory metal or polymer activation via a temperature change by application of RF energy, laser energy, ultrasonic energy, heating of a hot melt adhesive joint, ultrasonic joint degradation, hydrokinetic activation of a mechanical retaining device, and the like. Various detachment mechanisms known in the art are discussed in U.S. Pat. No. 5,722,989, J. Fitch et al:, U.S. Pat. No. 5,108,407, G. Geremia let al., U.S. Pat. No. 5,217,484, M. Marks, and U.S. Pat. No. 5,423,829, P. Pham, which are hereby incorporated by reference.
• Upon proper positioning of the[0063]space filling device70 within theaneurysm71, the device will assume a space filling folded or convoluted configuration due to the confinement of the aneurysm cavity, a secondary shape imparted to the device by an elongated longitudinal member having a secondary shape, or both of these. As a result of the folded or convoluted configuration of the space filling device, contact points78 as shown in the enlarged view of FIG. 18A will result. Upon transmutations of the transmutable material of thedevice70, contact points78 cross-link, bond, self adhere or the like to become attachment points which result in a more stable and rigid transmuted space filling device than would result without such attachment points. Such a configuration resists compaction and repositioning after deployment, and facilitates use in aneurysms or other bodily cavities having a dome to neck ratio of less than 2 to 1. It is believed that upon proper deployment of the space filling device of the present invention, flow of blood throughout the aneurysm will be sufficiently reduced for a sufficient time to allow clot formation within the aneurysm cavity. Eventually, the clot will organize and endothelial growth over the clot in the neck area of the filled aneurysm will ensue, completing the healing process. The resistance to compaction and reforming by the space filling device of the present invention is believed to facilitate the reduction of blood flow throughout the aneurysm for a sufficient time for this healing process to occur.
• As shown in FIG. 19, a blocking[0064]balloon86 may be deployed adjacent the neck ofaneurysm87 anddistal end74 of themicrocatheter73 prior to distally advancing the space filling device from the distal end of the microcatheter into the aneurysm. The blockingballoon86 facilitates maintaining thespace filling device70 within theaneurysm71 prior to transmutation of the transmutable material within the space filling device. In this way, aneurysms having a greater neck to dome ratio can be effectively treated.
• FIG. 20 shows a[0065]distal end90 of adelivery system91 detachably secured to afirst end92 of aspace filling device93 having features of the invention. Thedistal end90 of the delivery system has an elongatetubular shaft94 with an inner lumen95 disposed therein. A detachment signal conduit96 is disposed within the inner lumen95 of the shaft and is connected to adegradable polymer link97 at adistal extremity98 of the conduit. Afirst end101 of an elongatelongitudinal member102 is detachably secured to thedegradable polymer link97 to form adetachment mechanism103. Thedetachment mechanism103 can be activated by means of a signal transmitted through the detachment signal conduit96 which degrades the polymer link and releases thespace filling device93 from thedelivery system91. Thepolymer link97 is preferably degraded by a chain cleavage or scission reaction. Materials and methods suitable for such a mechanism are discussed generally in U.S. Pat. No. 5,443,495 which has been incorporated herein. The detachment signal transmitted through the detachment signal conduit96 is preferably a radiofrequency signal that initiates a chain cleavage reaction in thedegradable polymer link97, however, other signals or energy delivery may be used such as alternating or direct electric current, ultrasonic energy, laser energy or any other form of electromagnetic radiation or the like. The detachment signal conduit96 may be a single, double or multiple pole wire, coaxial cable, fiber optic, elongate ultrasonic energy transmitter, such as a solid rod of metal, glass or composite or the like. If a single pole wire is used, a current flow path may be established by the application of a conductive pad to a suitable portion of the patient's body, preferably with a highly conductive gel between the conductive pad and the patient's skin. Alternatively, a conductive needle, such as a stainless steel18 gauge needle, may be inserted into a suitable site of the patient to act as a ground. These grounding techniques may be used for any port of the invention requiring an electric current flow path, including the heating of elongated longitudinal or helical members for transmutation of transmutable materials.
• FIG. 21 shows a[0066]distal end107 of a delivery system108 detachably secured to afirst end109 of a space filling device111 having features of the invention. Thedistal end107 of the delivery system108 has an elongatetubular shaft112 with aninner lumen113 disposed therein. Adetachment signal conduit114 is disposed within theinner lumen113 of theshaft112 and is connected to adegradable polymer link115 at adistal extremity116 of the conduit. Thefirst end109 of the space filling device111 is detachably secured to thedegradable polymer link115 to form adetachment mechanism118. Thedetachment mechanism118 can be activated by means of a signal transmitted through thedetachment signal conduit114 which degrades thepolymer link115 and releases the space filling device111 from the delivery system108. The detachment signal transmitted through thedetachment signal conduit114 is preferably a low voltage direct current electric signal that heats aresistive element119 and initiates a chain cleavage reaction in thedegradable polymer link115. However, other signals or energy delivery may be used such as alternating or direct electric current, ultrasonic energy, laser energy or any other form of electromagnetic radiation or the like. Thedetachment signal conduit114 may be a single, double or multiple pole wire, coaxial cable, fiber optic, elongate ultrasonic energy transmitter, such as a solid rod of metal, glass or composite or the like.
• FIG. 22 shows a[0067]distal end121 of adelivery system122 detachably secured to afirst end123 of a space filling device124 having features of the invention. Thedistal end121 of the delivery system has an elongatetubular shaft125 with aninner lumen126 disposed therein. Adetachment signal conduit127 is disposed within theinner lumen126 of theshaft125 and is connected to amechanical capture device128 at adistal extremity129 of the conduit. Afirst extremity131 of an elongatelongitudinal member132 has anenlarged portion133 which is mechanically captured by a plurality ofcapture elements135 of themechanical capture device128. Thecapture elements135 can be activated by means of a signal transmitted through thedetachment signal conduit127 which causes thecapture elements135 to expand in an outward radial direction which releases theenlarged portion133 of the elongatedlongitudinal member132 and releases the space filling device124 from thedelivery system122. The detachment signal transmitted through the detachment signal conduit is preferably a low voltage electrical signal that heats thecapture elements135 which are made of a shape memory alloy such as NiTi and which are configured to have a remembered shape in an open expanded position which results upon heating of the elements. A similar result can be achieved in an alternative embodiment of a mechanical capture device which has capture elements which are radially constrained by an elongated tubular detachment signal conduit. Upon longitudinal retraction of the tubular conduit, the constraint of the capture elements is removed and an enlarged portion released. Alternative detachment signals include alternating or direct electric current, ultrasonic energy, laser energy or any other form of electromagnetic radiation or the like. The detachment signal conduit may be a single, double or multiple pole electrically conducting wire, coaxial cable, fiber optic, elongate tubular member with an inner lumen for conduction of hydrokinetic energy and activation of a hydrokinetic detachment mechanism, elongate ultrasonic energy transmitter, such as a solid rod of metal, glass or composite or the like. The detachment signal may also be in the form of mechanical actuation by longitudinal or rotational translation of a mechanical detachment signal conduit such as an elongate rod, shaft, or tubular member.
• FIG. 23 shows a[0068]distal end138 of adelivery system139 detachably secured to afirst end141 of aspace filling device142 having features of the invention. Thedistal end138 of the delivery system has an elongatetubular shaft143 with aninner lumen144 disposed therein. Adetachment signal conduit145 is disposed within theinner lumen144 of theshaft143 and is connected to amechanical capture device146 at adistal extremity147 of the conduit. Afirst extremity148 of an elongate longitudinal member149 has anenlarged portion151 which is mechanically captured by a helical capture element152 of themechanical capture device146. The helical capture element152 can be activated by means of a signal transmitted through thedetachment signal conduit145 which causes the capture element152 to expand in an outward radial direction which releases theenlarged portion151 of the elongated longitudinal member149 and releases thespace filling device142 from thedelivery system139. The detachment signal transmitted through thedetachment signal conduit145 is preferably a low voltage electrical signal that heats the capture element152 which is made of a shape memory alloy such as NiTi and which is configured to have a remembered shape in an open expanded position which results upon heating of the element. Alternative detachment signals include alternating or direct electric current, ultrasonic energy, laser energy or any other form of electromagnetic radiation or the like. Thedetachment signal conduit145 may be a single, double or multiple pole wire, coaxial cable, fiber optic, elongate ultrasonic energy transmitter, such as a solid rod of metal, glass or composite or the like.
• An alternative capture element for the mechanical capture device could include a tubular member, preferably in the form of a[0069]braided capture element160 as shown in FIGS. 24-26. Thebraided capture element160 as shown is constructed of braidedelongated filaments161 of a shape memory alloy, such as NiTi alloy. Thecapture element160 could also be a tubular member of shape memory polymer with similar properties. Theelongated filaments161 are arranged in a braided tubular structure with a firstinner diameter162 which is smaller than a nominal diameter or transverse dimension of anenlarged potion163, and which mechanically surrounds and captures the enlarged portion. The braided tubular structure of the capture element also has a second remembered inner diameter171 or transverse dimension which is greater than the transverse dimension of theenlarged portion163. In this way, the space filling device164 can be introduced into a desired area of a patient while secured to adistal end165 of adelivery system166 by the mechanical pressure of the firstinner diameter162 of thebraided capture element160 on theenlarged portion163 of thefirst end166 of the elongatedlongitudinal member167 of thespace filling device168. Upon placement of thespace filling device168 within the desired area within a patient, the shape memory elongatedfilaments161 can be activated so as to remember the larger second inner diameter171 releasing the enlarged portion and the space filling device into the desired area of the patient as indicated byarrow172. Activation of thebraided capture element160 could be carried out by the application of energy by the various methods described above. Such an embodiment of the capture element, as well as any other embodiment of the capture element discussed above, could be used to detach any of the various embodiments of the space filling device discussed herein.
• While particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.[0070]

Claims (20)

What is claimed is:

1. An intracorporeal space filling system for use in a patient's body, comprising;

an elongate tubular shell having an inner lumen disposed within the shell; and a transmutable material disposed within the inner lumen of the shell that is transmutable from a non-rigid state to a substantially rigid state within the patient's body; and

a delivery system having an elongate shaft with a distal end and a proximal end and a detachment mechanism disposed on the distal end of the elongate shaft and a first end of the elongate tubular shell detachably secured to the detachment mechanism;

wherein the detachment mechanism comprises a detachable polymer link.

2. The device ofclaim 1, wherein the detachable polymer link is severed in response to the application of heat.

3. The device ofclaim 1, wherein the detachment mechanism comprises a mechanical capture device which has a helical capture element disposed about and capturing an enlarged portion of an elongate longitudinal member which is secured to the space filling device whereby heat activation of the helical capture element causes the element to return to a remembered shape extending in an open outward radial direction releasing the enlarged portion of the elongated longitudinal member and the space filling device.

4. The device ofclaim 1, wherein the detachment mechanism comprises an electrolytically severable member securing the distal end of the delivery system to the first end of the space filling device whereby application of electrical current to the severable member erodes the member and releases the space filling device from the delivery system.

5. An intracorporeal space filing system comprising a space filling device having an elongated longitudinal member and a transmutable material disposed about the elongated longitudinal member and being transmutable from a non-rigid state to a substantially rigid state within a patient's body, and a delivery system having an elongate shaft with a distal end and a proximal end and a detachment mechanism disposed on the distal end of the elongate shaft and the first end of the space filling device detachably secured to the detachment mechanism.

6. The device ofclaim 5, wherein the detachment mechanism comprises a degradable polymer link which can be severed by a chain cleavage reaction.

7. The device ofclaim 5, wherein the detachment mechanism comprises a mechanical detachment mechanism.

8. A method of occluding an intracorporeal void, comprising:

(a) positioning the distal end of a microcatheter such that a distal port in the distal end is directed to the cavity of the intracorporeal void;

(b) distally advancing an intracorporeal space filling device comprising:

an elongate tubular shell which has a first port disposed at a first end and a second port disposed at a second end and an inner lumen disposed within the shell in fluid communication with the first port and second port; and

a transmutable material disposed within the inner lumen of the shell that is transmutable from a non-rigid state to a substantially rigid state within the patient's body,

(c) deploying the space filling device into the void;

(d) transmuting the transmutable material from a non-rigid state to a substantially rigid state; and

(e) detaching the space filling device from the delivery system by activation of a detachment mechanism after the space filling device has been positioned with the intracorporeal void.

9. The method ofclaim 8, wherein detachment is carried out by degradation of a polymer link between the distal end of the delivery system and the first end of the elongated shell.

10. The method ofclaim 9, wherein the degradation of the polymer link comprises a chain cleavage reaction.

11. The method ofclaim 8, wherein detachment is carried out mechanically.

12. The method ofclaim 8, wherein detachment is carried out by activation of a shape memory capture element.

13. The method ofclaim 8, wherein detachment is carried out by electrolytic degradation of an electrolytically degradable element.

14. The method ofclaim 8, further comprising deploying a blocking balloon adjacent the intracorporeal void and the distal end of the microcatheter prior to distally advancing the space filling intracorporeal device into the void.

15. A detachment mechanism for detaching an intracorporeal space filling device from a delivery system, comprising:

(a) a degradable polymer link securing the intracorporeal space filling device to the delivery system; and

(b) a heating element disposed in thermal contact with the degradable polymer link.

16. The detachment mechanism ofclaim 15, wherein the degradable polymer link is degraded by a chain cleavage reaction.

17. The detachment mechanism ofclaim 15, wherein the heating element is a resistive heating element configured to be heated by electric current passed therethrough.

18. A detachment mechanism for detaching an intracorporeal space filling device from a delivery system, comprising:

(a) a tubular braided capture element secured to a distal end of the delivery system having a first inner diameter and a second inner diameter larger than the first inner diameter upon activation of the braided capture element and a distal port in communication with an inner lumen; and

(b) an enlarged portion secured to the intracorporeal space filling device having a transverse dimension larger than the first inner diameter of the braided capture element and smaller than the second inner diameter of the braided capture element with the enlarged portion being within and captured by the first inner diameter of the braided tubular capture element.

19. The detachment mechanism ofclaim 18, wherein the tubular braided capture element comprises braided elongated filaments of shape memory material configured to have a remembered shape producing the second inner diameter.

20. The detachment mechanism ofclaim 19, wherein the capture element is configured to be activated from the first inner diameter to the remembered second inner diameter by the application of energy to the capture element which raises the temperature of the elongated shape memory filaments sufficiently to cause activation to the remembered shape.

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