Method and apparatus for fast electrolytic detachment of an implant

• US 6,425,893 B1
• Filed: 11/24/1999
• Issued: 07/30/2002
• Est. Priority Date: 03/13/1990
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Guglielmi, Guido
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/450,033
• Time in Patent Office: 979 Days
• Field of Search: 606/1, 606/32, 606/108, 606/191, 623/1
• US Class Current: 606/32
• CPC Class Codes: A61B 17/12022 Occluding by internal devices, e.g. balloons or releasable wires plugging an opening in the wall of an organ A61B17/0057; occluders for the cervical canal A61F6/146; vas deferens occluders A61F6/20
• CPC Class Codes: A61B 17/12113 within an aneurysm
• CPC Class Codes: A61B 17/1214 Coils or wires
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/12063 electrolytically detachable
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61B 2018/00678 upper
• CPC Class Codes: A61B 2018/00761 Duration
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00886 Duration
• CPC Class Codes: A61B 2018/1226 powered by a battery
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/126 bipolar
• CPC Class Codes: A61B 2018/1266 with DC current output
• CPC Class Codes: A61B 2018/1435 Spiral
• CPC Class Codes: A61B 2018/1495 Electrodes being detachable from a support structure
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61M 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: A61M 25/09 : Guide wires

Abstract

This is an implant for placement in the human body and a wire coupled to the implant for placing that implant. In the illustrated embodiment, it is an implant for use in the vasculature of the human body and is used to occlude a cavity in that vasculature as a portion of a treatment regimen. The implant itself is a component of a deployment device in which the implant is detached from the wire using electrolytic disintegration when a current is applied to the wire. The implant is electrically isolated from active participation in the electrolytic disintegration which occurs when a current is applied to the wire. Such isolation and minimization of the conductive pathway from the placement apparatus to the body'"'"'s fluids appears to enhance the susceptibility of a selected portion of the wire to electrolysis to provide for quick erosion and detachment of the implant from the wire. Although the implant itself is preferably a vaso-occlusive device, it may instead be used for any implant which may be installed in this manner.

Claims

1. An implant assembly for placement of an implant in the human body in presence of an ionic fluid comprising:

an implant member having a proximal end and a distal end, and

an electrolytically severable joint situated to release said implant member upon application of electrical energy to said electrolytically severable joint,

wherein said implant member is electrically isolated from electrolysis in said ionic fluid.

2. The implant assembly of claim 1 wherein said electrical isolation from electrolysis is due to an insulative or highly resistive layer coating all exposed surfaces of said implant member.

3. The implant assembly of claim 1 wherein the implant member comprises a helically wound coil.

4. An apparatus for occluding a body cavity in the presence of an ionic fluid comprising:

a wire having a proximal and distal end, said distal end being adapted to be positioned in or near said body cavity, said distal end of said wire being fully insulated except for a selected portion serving as an electrolytic joint;

a detachable implant coupled to said distal end of said wire, distal from said joint, said implant adapted to be positioned in said body cavity, said implant being electrically isolated from electrolysis in said ionic fluid, where substantially only said joint is electrolyzed when current is applied to said wire.

5. The apparatus of claim 4 wherein said implant is electrically isolated from electrolysis in said ionic fluid by electrical isolation from said ionic fluid.

6. The apparatus of claim 5 wherein said implant has surfaces in contact to said ionic fluid and is electrically isolated from said ionic fluid by an insulating coating on all surfaces of said implant in contact with or potentially in electrical communication with said ionic fluid.

7. An apparatus for occluding a body cavity in the presence of an ionic fluid comprising:

a wire having a proximal and distal end, said distal end of said wire being insulated;

an electrolytic joint coupled to said distal end, said electrolytic joint being insulated at least in part;

a detachable implant coupled to said electrolytic joint, said implant not being subject to electrolysis in said ionic fluid when current is applied to said wire, and where said joint is electrolyzed when current is applied to said wire to separate said implant from said wire.

8. The apparatus of claim 7 wherein said implant is not subject to electrolysis in said ionic fluid by virtue of electrical isolation of said implant from said ionic fluid.

9. The apparatus of claim 8 wherein said implant has surfaces in contact to said ionic fluid and is electrically isolated from said ionic fluid by an insulating coating on all surfaces of said implant in contact with or potentially in electrical communication with said ionic fluid.

10. A method for introduction of an implant into a space within the human body comprising:

placing a delivery catheter distal tip near said space within the human body;

introducing an implant assembly comprising;

said implant member having a proximal end and a distal end; and

an electrolytically severable joint attached to said implant member proximal end, wherein said implant member is electrically isolated from electrolysis;

placing said implant member into said space; and

electrolytically detaching said implant member from said implant assembly.