U.S. patent application number 11/061127 was filed with the patent office on 2005-10-06 for methods and devices for delivering occlusion elements.
This patent application is currently assigned to CONCENTRIC MEDICAL, INC., A Delaware Corporation. Invention is credited to Aboytes, Maria, Gia, Son, Gifford, Hanson S. III, Ken, Christopher, Patel, Tina, Pierce, Ryan, Sepetka, Ivan.
Application Number | 20050222580 11/061127 |
Document ID | / |
Family ID | 25120010 |
Filed Date | 2005-10-06 |
United States Patent
Application |
20050222580 |
Kind Code |
A1 |
Gifford, Hanson S. III ; et
al. |
October 6, 2005 |
Methods and devices for delivering occlusion elements
Abstract
A device for delivering an occlusion element, or other medical
device, which includes a fluid dissolvable bond. The occlusion
element is coupled to the delivery element with the fluid
dissolvable bond. The bond may be dissolved by delivering a fluid
through the delivery element either through the delivery element
itself or through a tube positioned in the delivery element.
Inventors: |
Gifford, Hanson S. III;
(Woodside, CA) ; Sepetka, Ivan; (Los Altos,
CA) ; Gia, Son; (San Jose, CA) ; Aboytes,
Maria; (East Palo Alto, CA) ; Pierce, Ryan;
(Mountain View, CA) ; Patel, Tina; (San Carlos,
CA) ; Ken, Christopher; (San Mateo, CA) |
Correspondence
Address: |
HOEKENDIJK & LYNCH, LLP
P.O. BOX 4787
BURLINGAME
CA
94011-4787
US
|
Assignee: |
CONCENTRIC MEDICAL, INC., A
Delaware Corporation
Mountain View
CA
|
Family ID: |
25120010 |
Appl. No.: |
11/061127 |
Filed: |
February 18, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11061127 |
Feb 18, 2005 |
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10072825 |
Feb 8, 2002 |
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6905503 |
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10072825 |
Feb 8, 2002 |
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09780587 |
Feb 9, 2001 |
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6494884 |
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Current U.S.
Class: |
606/108 ;
606/200 |
Current CPC
Class: |
A61B 17/1215 20130101;
A61B 17/1214 20130101; A61B 17/12022 20130101; A61M 25/007
20130101; A61B 2017/00477 20130101; A61B 2017/12059 20130101; A61B
17/12145 20130101 |
Class at
Publication: |
606/108 ;
606/200 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. A method of delivering an occlusion element, comprising the
steps of: providing an occlusion element which is coupled to a
delivery element with a dissolvable material, the dissolvable
material being dissolvable with a fluid, the dissolvable material
forming a dissolvable connection between the delivery element and
the occlusion element; advancing the occlusion element through a
patient's vascular system with the occlusion element coupled to the
delivery element with at least the dissolvable connection; and
dissolving the dissolvable material thereby releasing the occlusion
element from the dissolvable connection with the delivery
element.
2. The method of claim 1, wherein: the dissolving step is carried
out with the dissolvable material being dissolved faster by the
fluid as compared to other fluids contacting the material during
the advancing step.
3. The method of claim 1, wherein: the providing step is carried
out with the dissolvable material dissolving faster at a selected
pH as compared to a pH of other fluids which the material contacts
during the advancing step; and the dissolving step is carried out
by delivering a fluid having the selected pH to dissolve the
dissolvable material.
4. The method of claim 1, wherein: the dissolving step is carried
out with the dissolvable material and fluid being a solute and
solvent.
5. The method of claim 1, wherein: the dissolving step is carried
out by delivering a fluid to the dissolvable material, the fluid
being an acid..
6. The method of claim 1, wherein: the dissolving step is carried
out by delivering a fluid to the dissolvable material, the fluid
being a base.
7. The method of claim 5, wherein the dissolvable material includes
a material selected from the group consisting of zinc and iron.
8. The method of claim 1, wherein the dissolvable material is a
polymer.
9. The method of claim 9, wherein the dissolvable material is a
natural polymer.
10. The method of claim 9, wherein the dissolvable material is an
alginate.
11. The method of claim 9, wherein the dissolvable material is a
cross-linked polymer.
12. The method of claim 11, wherein the dissolving step is carried
out by delivering a fluid including a cation which dissolves the
cross-linked polymer.
13. The method of claim 8, wherein the polymer is in the form of
polymer layers bonded together.
14. The method of claim 13, wherein the polymer is an acrylic
polymer.
15. The method of claim 15, wherein the polymer is a methacrylate
polymer.
16. The method of claim 13, wherein the dissolving step is carried
out by delivering a fluid having a pH different than blood.
17. The method of claim 13, wherein the dissolving step is carried
out by using a fluid having a salinity different than blood.
18. The method of claim 17, wherein the dissolving step is carried
out with the fluid having a pH of 4-6.5.
19. The method of claim 17, wherein the dissolving step is carried
out with the fluid having a pH of 8-95.
20. The method of claim 17, wherein the dissolving step is carried
out with the fluid having a pH of less than 7.0.
21. The method of claim 17, wherein the dissolving step is carried
out with the fluid having a pH of greater than 7.4.
22. The method of claim 1, further comprising the step of: changing
a temperature of the dissolvable material during the dissolving
step.
23. The method of claim 22, wherein: the temperature changing step
is carried out by delivering the fluid at a temperature which
changes the temperature of the dissolvable material.
24. The method of claim 22, wherein: the temperature changing step
is carried out by directly heating the dissolvable bond.
25. The method of claim 24, wherein: the temperature changing step
is carried out by using resistive heating.
26. The method of claim 1, wherein: the dissolving step is carried
out by delivering the fluid to the material to dissolve the
dissolvable material.
27. The method of claim 26, wherein: the dissolving step is carried
out with the fluid being delivered through the delivery
element.
28. The method of claim 27, wherein: the dissolving step is carried
out with a tube positioned in the delivery element, the tube having
a lumen, the tube and delivery element defining a space
therebetween, the fluid being delivered through one of the lumen
and the space and the fluid being withdrawn through the other of
the lumen and the space.
29. The method of claim 1, wherein: the providing step is carried
out with the occlusion element forming coils.
30. The method of claim 1, wherein: the providing step is carried
out with the dissolvable material having a cavity.
31. The method of claim 30, wherein: the providing step is carried
out with the cavity being a throughhole.
32. The method of claim 1, further comprising the step of:
positioning a blocking element to impede fluid contact with a least
a protected portion of the dissolvable material, the blocking
element being movable to a position spaced apart from the protected
portion of the dissolvable material.
33. The method of claim 32, wherein: the blocking element is
positioned in a cavity in the dissolvable material.
34. The method of claim 33, wherein: the providing step is carried
out with the blocking element being a tube; and the method further
comprising the step of retracting the tube to expose at least part
of the dissolvable material.
35. The method of claim 33, wherein: the providing step is carried
out with the blocking element being a tube; and the dissolving step
being carried out with the fluid passing through the tube.
36. The method of claim 1, wherein: the providing step is carried
out with a flexible sheath extending over the dissolvable material,
the flexible sheath being attached to the delivery element.
37. The method of claim 1, wherein: the providing step is carried
out with the occlusion element having a portion embedded in the
dissolvable material.
38. The method of claim 37, wherein: the providing step is carried
out with the embedded portion being embedded in the dissolvable
material in an expanded position, the embedded portion being
naturally biased toward a collapsed position; and the dissolving
step is carried out so that the portion of the occlusion element is
no longer embedded in the material thereby permitting the portion
to move toward the collapsed position.
39. The method of claim 37, wherein: the providing step is carried
out with the portion embedded in the material including a plurality
of filaments.
40. The method of claim 37, wherein: the providing step is carried
out with the portion embedded in the dissolvable material being a
coil.
41. The method of claim 1, wherein: the providing step is carried
out with the occlusion element having a plurality of flexible
fibers embedded in the dissolvable material.
42. The method of claim 1, wherein: the providing step is carried
out with the portion embedded in the material including a ball.
43. The method of claim 1, wherein: the providing step is carried
out with the portion embedded in the material including a cage.
44. The method of claim 1, wherein: the providing step is carried
out with a flexible sheath covering at least a portion of the
dissolvable material.
45. The method of claim 44, wherein: the providing step is carried
out with the sheath having openings therein.
46. The method of claim 45, wherein: the providing step is carried
out with the delivery element having a fluid distributing portion
with openings for distributing the fluid; the dissolving step being
carried out to deliver the fluid through the openings in the
distributing portion to dissolve the material.
47. The method of claim 46, wherein: the providing step is carried
out with the distributing portion being conical.
48. The method of claim 1, further comprising the step of: moving
the delivery element relative to the occlusion element after the
dissolving step to fully release the occlusion element from the
delivery element.
49. The method of claim 1, wherein: the dissolving step fully
releases the occlusion element from the delivery element.
50. The method of claim 1, wherein: the providing step is carried
out with the occlusion element having a blocking portion which
isolates the material from the patient's blood; the advancing step
being carried out so that the blocking portion isolates the
material from the patient's blood during the advancing step.
51. The method of claim 50, wherein: the providing step is carried
out with the blocking portion being a plug of material.
52. The method of claim 51, wherein: the providing step is carried
out with the plug of material being solder.
53. The method of claim 50, wherein: the providing step is carried
out with the blocking portion being a disc.
54. The method of claim 1, wherein: the dissolving step is carried
out with the fluid being a fluid selected from the group consisting
of water, saline and the patient's own blood.
55. The method of claim 1, wherein: the providing step is carried
out with the material being selected from the group consisting of
sugar, salt, mannitol or a combination thereof.
56. The method of claim 1, wherein: the providing step is carried
out with the delivery element having a plurality of occlusion
elements; and the dissolving step is carried out a number of times
to sequentially release the plurality of occlusion elements.
57. The method of claim 56, wherein: the providing step is carried
out with the delivery element including a tube in which the
plurality of occlusion elements is positioned; the dissolving step
being carried out by moving the tube relative to the occlusion
elements to expose the dissolvable material to the fluid.
58. The method of claim 57, wherein; the providing step is carried
out with the tube having openings therein through which the fluid
passes to contact the dissolvable material.
59. The method of claim 58, wherein: the providing step is carried
out with the delivery element having an outer tube positioned
around the tube; and the dissolving step is carried out by
delivering the fluid through a lumen positioned between the tube
and outer tube.
60. The method of claim 59, wherein: the dissolving step is carried
out by withdrawing the fluid and dissolved parts of the dissolvable
material through another lumen between the tube and outer tube.
61. The method of claim 55, wherein: the dissolving step is carried
out by using a first fluid to dissolve one of the dissolvable
connections and a second fluid, different than the first fluid, to
dissolve another of the dissolvable connections.
62. The method of claim 1, further comprising the step of:
detecting whether the occlusion element has been released from the
delivery element.
63. The method of claim 62, wherein: the detecting step is carried
out by applying energy to the delivery element and detecting a
change in a parameter thereby indicating release of the occlusion
element.
64. The method of claim 63, wherein: the detecting step is carried
out by applying RF energy.
65. The method of claim 64, wherein: the detecting step is carried
out with the parameter being the standing wave ratio.
66. A system for delivering a medical device to a patient,
comprising: a delivery element; and a medical device coupled to the
delivery element with a dissolvable material, the dissolvable
material forming a dissolvable connection between the medical
device and the delivery element, the dissolvable material being
dissolvable with a fluid.
67. The system of claim 66, wherein: the medical device is an
occlusion element for occluding a vascular region.
68. The system of claim 67, wherein: the delivery element has a
lumen.
69. The system of claim 68, further comprising: a fluid source
coupled to the lumen.
70. The system of claim 69, wherein: the fluid source contains a
fluid selected from the group of fluids consisting of the patient's
own blood, water, saline, and combinations thereof.
71. The system of claim 66, wherein: the material is selected from
the group of materials consisting of sugar, mannitol, salt and
combinations thereof.
72. The system of claim 66, wherein: the dissolvable material has a
cavity.
73. The system of claim 72, wherein: the cavity has a
throughhole.
74. The system of claim 66, further comprising: a blocking element
positioned to impede fluid contact with a least a protected portion
of the dissolvable material, the blocking element being movable to
a position spaced apart from the protected portion of the
dissolvable material to permit dissolution of the protected
portion
75. The system of claim 74, wherein: the blocking element is
positioned in a cavity in the dissolvable material.
76. The system of claim 75, wherein: the blocking portion is a tube
positioned in the cavity.
77. The system of claim 66, wherein: the medical device has an
embedded portion which is embedded in the dissolvable material.
78. The system of claim 77, wherein: the embedded portion is
embedded in the dissolvable material in an expanded position, the
embedded portion being naturally biased toward a collapsed position
after dissolution of the dissolvable material.
79. The system of claim 77, wherein: the portion of the delivery
element embedded in the material has a plurality of filaments.
80. The system of claim 77, wherein: the portion embedded in the
dissolvable material is a coil.
81. The system of claim 66, further comprising: a flexible sheath
covering at least a portion of the dissolvable material.
82. The system of claim 81, wherein: the sheath has openings
therein.
83. The system of claim 66, wherein: the delivery element has a
fluid distributing portion with openings for distributing the
fluid.
84. The system of claim 83, wherein: the distributing portion is
conical.
85. The system of claim 66, wherein: the medical element has a
blocking portion which protects the material from exposure to fluid
outside the delivery device.
86. The system of claim 66, wherein: the blocking portion is a plug
of material.
87. The system of claim 86, wherein: the plug of material is
solder.
88. The system of claim 66, further comprising: a catheter having a
lumen; the delivery element being a wire; the medical device being
mounted to the wire with the dissolvable material.
89. The system of claim 88, further comprising: a source of fluid
coupled to the lumen, the fluid dissolving the material.
90. The system of claim 66, wherein: the delivery element has a
helical element; the helical element contacting the dissolvable
material to enhance the bond between the delivery element and the
material.
91. The system of claim 66, wherein: the delivery element has a
textured surface which contacts the dissolvable material.
92. The system of claim 66, wherein: the delivery element has a
preloaded portion which exerts a force on at least one of the
dissolvable material and the medical device.
93. The system of claim 92, wherein: the preloaded portion is
compressed in a loaded position and is expanded when in a released
position.
94. The system of claim 92, wherein: the preloaded portion is
radiopaque.
95. The system of claim 94, wherein: the preloaded portion has a
exposed portion which is exposed in the loaded position, the
exposed portion moving inside the medical device when moving to the
released position.
96. The system of claim 95, wherein: the exposed portion is
embedded in the dissolvable material, the dissolvable material
being attached to the delivery element.
97. The system of claim 94, wherein: the preloaded portion includes
a spring.
98. The system of claim 66, wherein: the medical device has a
preloaded portion which exerts a force on at least one of the
material and delivery element.
99. The system of claim 98, wherein: the medical device is an
occlusion element having coils which are in an expanded shape when
embedded in the material and which collapse when the material is
dissolved.
100. The system of claim 66, further comprising: means for heating
the material to enhance dissolution of the material.
101. The system of claim 100, wherein: the heating means uses
electrical energy and is a resistive heater.
102. The system of claim 66, wherein: a number of medical devices
are mounted to the delivery element.
103. The system of claim 102, wherein: a dissolvable connection is
provided between each of the medical devices
104. The system of claim 103, wherein: at least two of the
dissolvable connections are dissolved with different fluids.
105. A method of delivering a medical device, comprising the steps
of: providing a medical device which is coupled to a delivery
element with a dissolvable material, the dissolvable material being
dissolvable with a fluid, the dissolvable material forming a
dissolvable bond between the delivery element and the medical
device; advancing the medical device into a patient with the
medical device coupled to the delivery element; and dissolving the
dissolvable material thereby releasing the medical device from the
delivery element.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of Methods
and Devices for Delivering Occlusion Elements, Ser. No. 09/780,587,
filed Feb. 9, 2001, the full disclosures of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to the delivery of medical
devices and, in particular, occlusion elements. Occlusion elements,
such as coils, are delivered to occlude vascular regions and
malformations for various reasons. For example, occlusion elements,
such as coils, may be delivered into an aneurysm to occlude the
aneurysm. Other uses of occlusion elements include treatment of
AVM's and other malformations.
SUMMARY OF THE INVENTION
[0003] The medical device, such as the occlusion element, is
coupled to a delivery element with a material which is dissolvable
with a fluid. The material forms a dissolvable connection between
the delivery element and the occlusion element. The occlusion
element is advanced through the patient's vascular system and, at
the appropriate time, the material is dissolved. The dissolvable
material is preferably dissolved with a fluid which is delivered to
the material through the delivery element or through a tube
positioned in the delivery element. The fluid may be delivered,
withdrawn or otherwise circulated around the material with the tube
and delivery element in any suitable manner. Alternatively, the
material may be dissolved with the patient's own blood. Finally,
the fluid may also be contained within the delivery element but
separated from the material until the desired time. Although the
present invention provides a few exemplary fluids and dissolvable
materials, the fluid and dissolvable material combination may be
any suitable combination without departing from the scope of the
invention.
[0004] The occlusion element may be embedded in the material. For
example, the occlusion element may have a coil, a plurality of
filaments, a ball or a cage embedded in the material. The embedded
portion may also be in a biased position, either expanded or
collapsed, when embedded in the material. In this manner, the
embedded portion helps to mechanically disturb the dissolvable
portion to release the device as the material dissolves. For
example, the embedded portion may be a stacked coil which expands
when released. The delivery element itself may also have a portion
embedded in the material, such as a number of filaments, to further
secure the delivery device to the occlusion element.
[0005] A blocking element may also be provided which protects part
of the dissolvable material from exposure to blood or other fluids.
The blocking element may be positioned within a cavity in the
material. The cavity may be a throughhole through which the fluid
is delivered when dissolving the material. The blocking element may
also help to protect the connection from kinking and other
mechanical disturbances which occur when advancing the occlusion
element through small, tortuous vessels. The blocking element can
prevent inadvertent mechanical detachment when the device is bent
or otherwise deformed during advancement through the patient. The
occlusion element itself may also have a blocking portion which
prevents contact between the patient's blood and the material
thereby inhibiting premature dissolution of the material. The
blocking portion may be a plug of material such as solder.
[0006] A flexible sheath may also be positioned over the material
to protect the material. The sheath may be solid or may have
openings or slits therein to promote flow through the sheath when
dissolving the material. The delivery element may also have a fluid
distributing portion which distributes the fluid for dissolution of
the material.
[0007] These and other advantages of the invention will become
apparent from the following description of the preferred
embodiments, claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a system of the present invention.
[0009] FIG. 2 shows an occlusion element.
[0010] FIG. 3 shows the occlusion element mounted to a delivery
element.
[0011] FIG. 4 shows the distal end of the delivery element with a
blocking element removed from a cavity in the dissolvable
material.
[0012] FIG. 5 shows the distal end of the delivery element with the
dissolvable material dissolved and the occlusion element
released.
[0013] FIG. 6 shows another device for delivering the occlusion
element.
[0014] FIG. 7 shows the device of FIG. 6 after partial dissolution
of the material.
[0015] FIG. 8 shows the occlusion element released from the
delivery device.
[0016] FIG. 9 shows still another device for delivering an
occlusion element.
[0017] FIG. 10 shows the occlusion element of FIG. 10 released from
the delivery element.
[0018] FIG. 11 shows yet another device for delivering an occlusion
element.
[0019] FIG. 12 shows the occlusion element of FIG. 11 released from
the delivery element.
[0020] FIG. 13 shows yet another device for delivering an occlusion
element.
[0021] FIG. 14 shows the occlusion element of FIG. 13 released from
the delivery element.
[0022] FIG. 15 shows another device for delivering an occlusion
element with the occlusion element inhibiting fluid contact with
the material.
[0023] FIG. 16 shows the occlusion element of FIG. 16 released from
the delivery element.
[0024] FIG. 17 shows still another device for delivering an
occluding element.
[0025] FIG. 18 shows the occlusion element of FIG. 17 released from
the delivery element.
[0026] FIG. 19 shows still another device for delivering an
occluding element.
[0027] FIG. 20 shows the occlusion element of FIG. 19 released from
the delivery element.
[0028] FIG. 21 shows another device for delivering the occluding
element.
[0029] FIG. 22 shows the device of FIG. 21 with the material
partially dissolved.
[0030] FIG. 23 shows the device of FIGS. 21 and 22 with the
material dissolved to release the occlusion element.
[0031] FIG. 24 shows the occluding element mounted over another
delivery element with the delivery element having a coil.
[0032] FIG. 25 shows another delivery device having a textured
surface over which the dissolvable material is mounted.
[0033] FIG. 26 shows the delivery element having a preloaded
portion which exerts a releasing force on the occlusion
element.
[0034] FIG. 27 shows the occlusion element released.
[0035] FIG. 28 shows the occlusion element having a preloaded
portion embedded in the material.
[0036] FIG. 29 shows the material dissolved and the occlusion
element released.
[0037] FIG. 30 shows a heating element which is used to heat the
material to aid in dissolution of the material.
[0038] FIG. 31 shows another system for delivering the occlusion
element.
[0039] FIG. 32 shows the system of FIG. 31 with a tube retracted to
expose the material.
[0040] FIG. 33 shows a system for delivering a number of occlusion
elements.
[0041] FIG. 34 is a cross-sectional view of the system of FIG. 33
along line I-I.
[0042] FIG. 35 shows another system for use with the devices and
methods of the present invention.
[0043] FIG. 36 shows another multiple element delivery system.
[0044] FIG. 37 shows still another system for delivering a medical
device, such as the occlusion element, with a threaded portion
embedded in the dissolvable material.
[0045] FIG. 38 shows the material dissolved and the threaded
portion released.
[0046] FIG. 39 shows another system for delivering an occlusion
element which has preloaded portion embedded in the dissolvable
material.
[0047] FIG. 40 shows the preloaded portion released.
[0048] FIG. 41 shows another system for delivering the occlusion
element.
[0049] FIG. 42 shows the system of FIG. 41 with the occlusion
element released.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0050] Referring to FIGS. 1-4, a system 2 for delivering a medical
device 4, such as an occlusion element 6, is shown. The invention
is described in connection with delivery of the occlusion element
6, however, the devices and methods of the present invention may be
used to deliver any other medical device to any part of the body
without departing from the scope of the invention. The system 2
includes a delivery element 8 to which the occlusion element 6 is
mounted. A fluid dissolvable material 10 forms a dissolvable
connection between the occlusion element 6 and the delivery element
8. For example, the material may be a sugar (such as mannitol),
salt or combination thereof or the material may be a polymer which
is dissolved with a fluid having a specific pH range. These and
other examples and combinations of fluid and dissolvable material
10 are provided below. The material 10 and fluid used to dissolve
the material 10 may be any suitable combination and numerous
combinations not described herein may be used without departing
from the scope of the invention.
[0051] The occlusion element 6 is shown as a short section of coil
for clarity but may be any suitable occlusion element 6 such as
those described in U.S. Pat. Nos. 5,855,578, 5,853,418, 5,749,894
and 5,749,891 which are hereby incorporated by reference. In the
preferred embodiment, the occlusion element 6 is made of platinum
wire or ribbon which forms coils 7. Of course, any suitable
materials and structure may be used to form the occlusion element
6. The delivery element 8 is preferably a tube 11 having at least
one lumen 12, however, the delivery element 8 may also be a solid
element such as a wire or mandrel without departing from the scope
of the invention. The occlusion element 6 is mounted to the end of
the delivery element 8 and extends from the delivery element.
[0052] The system 2 of FIG. 1 shows delivery of the occlusion
element 6 to the cerebral vasculature, however, the system, devices
and methods of the present invention may be used to deliver the
occlusion element 6, or other medical device, to any location in
the patient. The system 2 includes a guide catheter 5 which is
advanced to a suitable location. A microcatheter or sheath 12 may
then be advanced through the guide catheter 5. The delivery element
8 is then advanced through the microcatheter 12 to the desired
release site. The microcatheter or sheath 12 may hold the occlusion
element 6 in a collapsed condition as demonstrated in the patents
incorporated by reference above. The element 6 forms the coiled
structure of FIG. 2 as it exits the distal end of the sheath 12.
The delivery element 8 may receive a blocking element 14 which is
described in further detail below. A fluid circulating device 15,
such as a source of fluid 16, is coupled to the delivery element 8
for delivery of the fluid that dissolves the material 10. The fluid
may be any suitable fluid such as saline but may also be the
patient's own blood, a mixture of saline and contrast to visualize
the area or any combination thereof.
[0053] The occlusion element 6 is mounted to the delivery element 8
with the fluid dissolvable material 10 which forms a dissolvable
bond or connection 11. The fluid is preferably delivered to the
dissolvable material 10 from the source of fluid 16 so that the
dissolution of the material 10 may be controlled by delivery of the
fluid. Although it is preferred to deliver the fluid to dissolve
the material 10, however, the fluid may also simply be the
patient's own blood. Such a device may be practiced with various
aspects of the invention described herein without departing from
the scope of the invention.
[0054] The fluid may simply erode or dissolve the bond 12 or the
material 10 may be dissolved with additional chemical, thermal or
mechanical action. For example, the fluid may be an acid, base or
other ionic fluid which chemically dissolves the material 10. For
example, hydrogen chloride may be used to dissolve a connection
having zinc or hydrogen peroxide may be used to dissolve a
connection having iron. The fluid 16 and material 10 may also form
a solvent/solute relationship such as Hypan dissolved by a fluid
such as dimethyl sulfoxide.
[0055] In still another example, the material 10 may be a
cross-linked polymer such as a cross-linked alginate. The alginate
may dissolve in the presence of a suitable fluid containing a
monovalent, divalent, or trivalent cation such as saline. The
alginate may be cross-linked in any suitable manner such as with
calcium chloride.
[0056] In still another example, the material may be a polymer
which preferentially dissolves upon a pH or salinity change or upon
application of an electric field. Such a polymer is sold under the
trade name EUDRAGIT.RTM. by Rohm GmbH of Darmstadt, Germany, which
is an acrylic polymer and more specifically a methacrylate polymer.
The polymer compound has polymer layers bonded together with
hydrogen bonds in alternating layers of positive and negative
charge. The bond between the polymer layers is broken by
application of the pH or salinity change or upon application of an
electric field. For example, the fluid 16 may also have a pH which
dissolves the material 10 faster than the pH of other fluids which
the material 10 is exposed to. Thus, if the material 10 is exposed
to blood, saline, contrast and the like, the dissolvable material
10 is preferably selected to at least dissolve slowly, if at all,
at the pH of these fluids and more quickly when exposed to the
appropriate pH fluid. In a preferred embodiment, the material
dissolves at least three times faster, and more preferably at least
five times faster at the selected pH than at the pH of other fluids
to which it is exposed. The dissolution rate can also be enhanced
by flowing fluid into contact with the dissolvable material.
[0057] Once the occlusion element is at the desired location, a
fluid, such as sodium bicarbonate, having the appropriate pH is
delivered to dissolve the material 10. As mentioned above, the
material 10 may dissolve slowly in the fluids to which it is
exposed so long as the material dissolves faster when exposed to
the appropriate fluid. EUDRAGIT.RTM., for example, dissolves slowly
in blood or saline, however, the polymer dissolves much faster with
the appropriate fluid. In a preferred embodiment, the fluid has a
pH of either about 4-6 or about 8-9.5.
[0058] In a specific example, EUDRAGIT.RTM. L100 and S100 (1:1) are
dissolved with an ethyl alcohol/water (95:5 by weight) solvent at a
ratio of 0.05 G EUDRAGIT.RTM. per gram of solution using a magnetic
mixer. Small drops of the EUDRAGIT.RTM. solution are then applied
to the appropriate area between the medical device or element and
the delivery or insertion element. The drop is then dried which may
take 1-5 hours during which time the solvent substantially
evaporates leaving the EUDRAGIT.RTM. material to form the
dissolvable bond. If necessary or desired, additional drops or
coatings may be applied after the previous drop, coating or
application has dried.
[0059] Thus, it can be appreciated from the various examples
provided above that a number of different combinations of fluid and
dissolvable material may be used and numerous other combinations
are possible without departing from the invention.
[0060] Referring again to FIG. 3, the blocking element 14 may be
used to protect parts of the dissolvable material 10 during
introduction and advancement of the occlusion element 6. The
blocking element 14 may simply be a wire, guidewire, mandrel or
even a tube. The blocking element 14 may be positioned adjacent or
against any portion of the material 10 and is preferably positioned
in a cavity 18 in the material 10. The cavity 18 is shown as a
throughhole 20 but may take any other shape such as a hole closed
on one end. The blocking element 14 temporarily blocks the cavity
18 to inhibit dissolution of the material 10. When the blocking
element 14 is withdrawn, part of the material 10 is exposed thereby
permitting dissolution of the material 10. Of course, fluid may be
in contact with the material 10 even with the blocking element 14
positioned in the cavity, however, the blocking element 14 will at
least inhibit fluid flow around the dissolvable material 10 thereby
preventing premature dissolution of a substantial portion of the
material 10.
[0061] The delivery element 8 may include a sheath 22 extending
over an outer surface of the dissolvable material 10. The sheath 22
protects the outer surface of the material 10 to inhibit
dissolution of the material 10. The sheath 22 may be any suitable
flexible sheath and may be made of any suitable material such as
PET. The delivery element 8 has a coil 24 coupled to a tube 26. The
coil 24 provides a flexible distal end for advancement of the
delivery element 8 through tortuous vessels. The sheath 22 may
extend over the coil 24 and tube 26 or only over a portion of the
coil 24 and material 10.
[0062] Referring to FIGS. 6-8, another device for delivering the
occlusion element 6 is shown wherein the same or similar reference
numbers refer to the same or similar structure. The delivery
element 8A has openings 28 therein through which fluid is delivered
when dissolving the material 10. The openings 28 may be in the
sheath 22A extending over the material 10. The openings 28 may also
be one or more slits 30 in the sheath 22A which open when positive
pressure is applied so that the slit 30 acts as a valve which opens
when the fluid is delivered yet covers the material 10 during
introduction and advancement. The openings 28 may also be part of a
portion 32 of the delivery element 8 that extends into the material
10. The portion 32 extending into the material 10 may, for example,
be a conical section 34. The openings 28 serve as fluid channels
when dissolving the material 10 so that the material 10 may be
dissolved relatively quickly at the desired time. An advantage of
such a design is that the dissolvable material 10 may be kept
relatively robust while maintaining the ability to quickly dissolve
the bond at the appropriate time. Use of the blocking element 14
(FIG. 2) further enhances the ability to control dissolution of the
dissolvable material 10 as discussed above and specifically
incorporated here.
[0063] Referring to FIGS. 9 and 10, still another device for
delivering an occlusion element 6B is shown wherein the same or
similar reference numbers refer to the same or similar structure.
The occlusion element 6B has a portion 40 embedded in the
dissolvable material 10. The portion 40 is preferably naturally
biased toward the collapsed position of FIG. 10 when released. The
dissolvable material 10 is shown as a solid plug of material 10 but
may, of course, have the cavity or throughhole as shown in
connection with FIGS. 3-8 without departing from the scope of the
invention. A tube 42 delivers, withdraws or otherwise circulates
the fluid to dissolve the material 10 at the desired time. The tube
42 and lumen 12 in the delivery element 8 are coupled to the fluid
circulating devices 15. The fluid circulating devices 15 may be
either the fluid source 16 with pump or a fluid withdrawal device
17, such as a vacuum source or vacuum pump, which are used to
circulate the fluid around the material 10. For example, the fluid
may be delivered through either the tube 42 or through the annular
area between the delivery element 8 and tube 42 with the other
element being used to withdraw the fluid. Alternatively, the tube
42 may be used with the fluid withdrawal device 17 to withdraw
fluid into the tube 42 while drawing the fluid through the lumen
12. Of course, the fluid may also be simply pulsed one way and then
the other so long as the fluid is generally being circulated
through the area to dissolve the material 10. One advantage of such
as system is that the dissolved material 10 may be withdrawn
through the delivery element 8 or tube 42.
[0064] The tube 42 and annular area between the delivery element 8
and tube 42 may also be used to prime the device with a suitable
fluid. The priming fluid may be a fluid which does not dissolve the
material 10 or which dissolves the material 10 very slowly. The
tube 42 and annular area between the delivery element 8 and tube 42
may also be used to actively remove air as well as for delivery of
the fluid after advancing the device to the desired release site.
Although the devices described herein include a separate tube 42,
the device 8 may also simply have two lumens instead of the tube 42
without departing from the scope of the invention.
[0065] Referring to FIGS. 11 and 12, yet another device for
delivering an occlusion element 6C is shown wherein the same or
similar reference numbers refer to the same or similar structure.
The occlusion element 6C has a plurality of filaments 44 embedded
in the dissolvable material 10. The tube 42 may be used to
circulate the fluid and dissolve the material 10 at the desired
time. Referring to FIGS. 13 and 14, still another device 8D for
delivering an occlusion element 6D is shown wherein the same or
similar reference numbers refer to the same or similar structure.
The delivery element 8D has a plurality of filaments 44 embedded in
the dissolvable material 10. An advantage of the device 8D is that
the filaments 44 are not part of the occlusion element 6D so that
the occlusion element 6C may be substantially a conventional
occlusion element 6D. The occlusion element 6D also has a distal
block 46, which inhibits, and preferably prevents, fluid from
entering the distal end of the delivery element 8 to protect the
dissolvable material 10 from exposure to blood. The distal block 46
is preferably solder 48 but may be any other suitable material
10.
[0066] Referring to FIGS. 15 and 16, yet another device for
delivering an occlusion element 6E is shown. The occlusion element
6E has a blocking element 50, which is preferably a first disc 52,
which prevents exposure of the material 10 to blood. A second disc
54, or other suitable shape, anchors the occlusion element 6 to the
material 10. A third disc 56 serves to move the coil out of the
delivery element 8 after melting of the dissolvable material 10.
The pressure of the fluid is increased so that the pressure forces
on the third disc 56 push the occlusion element 6E out of the
delivery element 8. The third disc 56, of course, does not
completely prevent proximal exposure of the dissolvable material 10
since the fluid is delivered through the delivery element 8,
preferably with the tube, to melt the dissolvable material 10.
[0067] Referring to FIGS. 17 and 18, another occlusion element 6F
is shown. The occlusion element 6F has a ball 58, preferably
0.005-0.020 in diameter, embedded in the material 10. The ball 58
is attached to the rest of the occlusion element 6F with solder 60
which also serves as a blocking element 63 to prevent distal
exposure of the dissolvable material 10. Referring to FIGS. 19 and
20 still another occlusion element 6G is shown which has a cage 62
embedded in the material 10. The cage 62 is attached to the rest of
the occlusion element 6 with solder 60 which also serves as the
blocking element 63 to prevent distal exposure of the dissolvable
material 10.
[0068] A method of delivering a medical device, such as an
occlusion element 6, is now described in connection with the
preferred embodiments, however, it is understood that the method
may be practiced with any suitable device. As mentioned above, the
invention may be used in any location in the patient's body and use
in the cerebral vasculature is described as a particular use of the
invention although any other medical device may be delivered to any
other part of the body for any other purpose. The guide catheter 5
is introduced into a vessel, such as the femoral artery, and
advanced to a suitable location. The microcatheter 12 is then
advanced through the guide catheter 5 to a location near the
desired site for releasing the occlusion element 6. The invention
may be practiced with fewer or more delivery catheters, cannulae or
sheaths without departing from the scope of the invention.
[0069] The occlusion element 6 is delivered to the desired location
by manipulating the delivery element 8. At the desired release time
and location, the blocking element (FIG. 2), if used, may be moved
to expose at least part of the dissolvable material 10. Fluid is
then delivered with the delivery element 8 and/or tube 42 to
dissolve the material 10 and release the occlusion element 6.
Depending upon the particular embodiment, the release of the
occlusion element from the dissolvable bond may completely release
the occlusion element 6 from the delivery element 8 or the delivery
element 8 may need to be withdrawn to completely release the
occlusion element 6. An advantage of requiring additional
withdrawal of the delivery element is that the occlusion element 6
may still be manipulated to some degree after release from the
dissolvable bond. For example, the delivery element 8 may be
advanced and manipulated further to move the occlusion element 6
after dissolution of the material 10.
[0070] Referring to FIGS. 21-23, another device 64 for delivering
the occlusion element 6 is shown. The device 64 includes the
dissolvable material 10 that dissolves upon application of the
fluid 16. As with all of the embodiments described herein, the
material 10 and fluid 16 may be any of those described herein or
any other suitable combination. The element 6 is mounted to the
delivery element 8 which may be a wire 66. The device 64 is
advanced through a catheter 68 such as the microcatheter or sheath
12. The device 64 is advanced through a lumen 70 in the catheter 68
and, at the desired time, the fluid 16 is delivered through the
lumen 70 to dissolve the material 10. The lumen 70 may be filled or
prepped with a fluid which does not dissolve the material 10 during
loading and advancement of the element 6 through the catheter 12.
For example, the device 64 may be prepped with saline and the fluid
used to dissolve the material 10 may utilize a change in pH as
described above. FIG. 22 shows the dissolvable material partially
dissolved and FIG. 23 shows the element 6 released from the
device.
[0071] Referring to FIGS. 24 and 25, another device 72 for
delivering the occlusion element 6 is shown. Similar to the device
of FIGS. 21-23, the dissolvable material 10 is dissolved with the
fluid delivered through the lumen 70 in the catheter 12. The
insertion element 8 may have features which enhance the bond
between the insertion element 8 and material 10. For example, a
helical wire or ribbon 73 can be wrapped around the insertion
element 8 (FIG. 24) or the surface of the insertion element may be
roughened or textured (FIG. 25) to enhance engagement with the
dissolvable material 10.
[0072] Referring to FIGS. 26 and 27, the devices described herein
may also have features which promote detachment of the element 6
from the insertion element 8. For example, the insertion element 8
may exert a force on the occlusion element 6 which helps to detach
the occlusion element 6. The pre-loaded force may be imparted in
any suitable manner such as with a spring 74. The spring 74 is
compressed in the loaded position of FIG. 26. As the material
dissolves in the fluid, the spring 74 helps to mechanically disturb
the dissolvable material 10 and also tends to force the element 6
away from the insertion element 8. FIG. 27 shows the spring 74
extended after detachment of the occlusion element 6. The spring 74
may be radiopaque so that expansion of the spring may be visualized
to monitor release of the device or element.
[0073] Referring to FIGS. 28 and 29, the element 6 itself may be
pre-loaded to exert forces on the dissolvable material. Proximal
windings 76 of the coil 78 can be stretched or compressed to
pre-load the windings 76 which are then embedded in the dissolvable
material 10. In this manner, the windings 76 themselves act to
mechanically disturb the material 10 thereby promoting detachment
of the element 6. Pre-loading of the element 6 may be used with any
of the embodiments described herein (such as FIG. 9) or other
suitable structures.
[0074] Referring to FIG. 30, another device 79 for delivering the
medical device, such as the occlusion element 6, is shown. The
device 79 also has the fluid dissolvable material 10 that is
dissolved to release the element 6. Similar to the use of a pH
change to enhance dissolution, the material 10 may dissolve at a
faster rate at a selected temperature. The temperature may be
changed by simply heating or cooling the fluid or by heating the
material 10 itself. The fluid may be heated and cooled with the
fluid circulating device 15 or with an element mounted to the
device itself. For example, a heating element 80, which may use
simple resistive heating, may be mounted to the device or delivered
through a lumen in the device to heat the material 10. Referring to
FIG. 30, the heating element directly contacts the material 10 to
heat the material 10.
[0075] Referring to FIGS. 31 and 32, another blocking element 82 is
shown which protects the dissolvable material 10. The blocking
element 82 is a tube 84 that covers an interior surface 86 of the
material 10. An outer tube 85 covers the outer surface of the
material 10. The blocking element 82 is retracted to expose an
inner tube 88 having openings 90 therein which permit fluid to
contact the material 10 as shown in FIG. 32. The inner tube 88 may
also be retracted to further expose the dissolvable material or the
inner tube 88 may be omitted altogether. The fluid is delivered
through a lumen 92 to dissolve the material 10.
[0076] The present invention may also be used to deliver a number
of elements 6 with the same delivery element 94. Referring to FIGS.
33 and 34, a number of the elements 6 are mounted to the insertion
element 94 which may be a tube, shaft, wire or mandrel. The
elements 6 are coupled to one another with the dissolvable material
10 to form a dissolvable connection between each of the elements.
Two lumens 96, 98 are formed between inner and outer tubes 100, 102
with the fluid being delivered through one of the lumens 96 and
withdrawn through the other lumen 98 (FIG. 34). The fluid passes
through openings 104 in the inner tube 100 and into contact with
the dissolvable material 10. The fluid, together with the dissolved
material 10, is then withdrawn through openings 106 in the other
side of the inner tube 100 and out through the other lumen 98.
After the occlusion element 6 has been released, the delivery
element 94 is advanced to position another of the dissolvable
connections between the openings 104, 106 to dissolve another
connection. This process is repeated until all of the occlusion
elements 6, or a desired number, have been released.
[0077] Referring to FIG. 35, a system 110 for flushing the device
with a flushing fluid 112 is shown. The flushing fluid 112 is
delivered to eliminate the fluid 114 used to dissolve the material
10. Flushing the system is particularly useful when delivering a
number of elements 6 with the same delivery device to prevent
premature release or degradation of the dissolvable connections.
The flushing fluid 112 and fluid 114 used to dissolve the material
may be coupled to a fluid control system 116 that controls delivery
of the two fluids. The fluid control system 116 may include a
detector 1 18, described below, which detects when an element 6 has
been released so that the flushing fluid 1 12 can then be
delivered. When the user desires to deliver another element 6, the
user prompts the system to switch back to delivery of the fluid 114
which dissolves the material for release of another element 6.
[0078] As mentioned above, the detector 118 is particularly useful
with the multiple element system described above but may be used to
simply alert the user when the element 6 has been detached so that
the user manipulates the insertion element appropriately once
detachment has occurred. Detecting detachment of the element 6 may
also be used to determine when to flush the system with the
flushing fluid 112. One method of detecting detachment is to apply
energy to the device and detect a change in a measured parameter or
characteristic of the energy. For example, the detector 118 may
apply a low power RF signal with the standing wave ratio (SWR)
being measured. The SWR will change when the element 6 has been
released so long as an appropriate frequency and/or wavelength is
selected. Other types of energy, such as electrical energy, may be
used while measuring other parameters, such as electrical
resistance, without departing from the scope of the invention.
[0079] Referring to FIG. 36, another multiple release system 120 is
shown. The occlusion elements 6 have coils 122 with a hub 124
mounted to each end. The coils 122 and hub 124 are embedded in the
dissolvable material 10 to form a dissolvable connection 125
between each of the elements 6. In another aspect of the invention,
different fluids may be used to dissolve each of the connections
125 between the occlusion elements 6. In this manner, premature
release of one or more of the elements 6 or premature degradation
of the material 10 is reduced. For example, the pH may be varied to
preferentially dissolve the connections 125 one at a time with each
of the connections being dissolved by a different pH fluid.
[0080] Referring to FIGS. 37 and 38, another system 127 for
releasing the occlusion element 6 is shown. The occlusion element 6
has a portion 128 embedded in the dissolvable material. The portion
128 preferably includes a flexible filament 130, such as suture,
which is attached to the element 6. The filament 130 may be one or
more filaments 130 extending somewhat independently similar to
FIGS. 11-14 or may form a wound, woven or braided structure. The
fluid is delivered through a lumen 129 to dissolve the material and
release the occlusion element 6 as shown in FIG. 38.
[0081] Referring to FIGS. 39 and 40, still another system 131 for
releasing the occlusion element 6 is shown. The occlusion element
has an embedded portion 134 which is embedded in the dissolvable
material. The embedded portion 134 is also preloaded under tension
but could also be preloaded under compression. The portion may be
any suitable structure such as a first coil 136 attached to a
second coil 138. The first coil 136 is relatively flexible and
stretches to the expanded position of FIG. 39 while the second coil
138 is stiffer and expands less. When released, the embedded or
preloaded portion 134 moves to the position shown in FIG. 40. The
embedded portion 134 moves into the occlusion element 6, and
specifically within the coils, so that the embedded portion does
not protrude from the coil a significant distance when
deployed.
[0082] Referring to FIGS. 41 and 42, another system 135 for
releasing an occlusion element 6 is shown. The system has a
delivery element 140 having an extension 142 which extends into the
occlusion element 6 and, in particular, inside a cavity 144 such as
the windings of the occlusion element 6. In this manner, the
delivery element 140 protects the dissolvable material and acts
like a blocking element in the manner described herein. The
extension 142 also helps to reinforce the area around the
dissolvable material 10 to prevent mechanical disturbance of the
dissolvable material 10 when the catheter is bent or twisted during
advancement. A tube or stylet 144 may be positioned in the delivery
element to improve column strength during delivery. Fluid is
delivered through the lumen 146 to dissolve the material at the
desired time. The fluid flows out of the extension 142 and into
contact with dissolvable material 10. The delivery element, like
any of the delivery elements or catheters described herein, may
have increased flexibility toward the distal end as is known in the
art.
[0083] The present invention has been described in connection with
the preferred embodiments, however, many variations and alternative
embodiments fall within the scope of the invention. For example,
the occlusion element may have any shape and may be made of any
material. Furthermore, although it is preferred to deliver the
fluid to the dissolvable material, the material may also be
dissolved by simply coming into contact with the patient's blood
without departing from various aspects of the invention. The
dissolvable material may completely detach the occlusion element
from the delivery element or may require another action, such as
withdrawal of the delivery element, to fully release the occlusion
element. Finally, the methods and devices of the present invention
may be used with any medical device and not necessarily the
occlusion elements described herein and use with any suitable
medical device falls within the scope of the invention so that the
term medical device or element may be substituted for occlusion
element or device as used herein. Thus, the description of the
preferred embodiments should not limit the invention. The invention
has been described in connection with a number of different
features, aspects and advantages which should be considered
independently and, thus, no single aspect or advantage of the
invention should be considered an essential element of the
invention. For example, various aspects of the invention may be
practiced with or without various aspects such as the blocking
element, sheath, or fluid circulation.
* * * * *