Surgery – Instruments
Reissue Patent
1997-07-07
2001-03-27
Dawson, Glenn K. (Department: 3761)
Surgery
Instruments
C128S898000, C606S151000, C606S200000
Reissue Patent
active
RE037117
ABSTRACT:
FIELD OF THE INVENTION
This invention is a surgical instrument and specifically is a device for delivering embolic coils to a selected site within the vasculature of a human body via use of a catheter. In particular, the device uses embolic coils having interlocking clasps on the coils which are secured to each other by a control wire within the catheter. Retraction of the control wire into the catheter body uncouples the distal coil.
BACKGROUND OF THE INVENTION
The endovascular treatment of a variety of vascular maladies throughout the body is an increasingly more important form of therapy. Catheters have been used to place various treatment materials, devices, and drugs within arteries and veins in the human body. Examples of these devices and their use in such treatments are shown in commonly assigned U.S. patent application Ser. Nos. 07/806,898 (“Detachable Pusher-Vasoocclusive Coil Assembly with Threaded Coupling”) and 07/806,912 (“Detachable Pusher-Vasoocclusive Coil Assembly with Interlocking Ball and Keyway Coupling”). These show methods and devices for delivery of coils or wires within the human body to sites such as aneurysms, to occlude those sites. Coils such as are discussed in those two documents (as well as in U.S. Pat. No. 4,994,069), may be of a regular or helical configuration or assume a random convoluted configuration at the site. The coils normally are made of a radiopaque, biocompatible metal such as platinum, gold, tungsten, or alloys of these and other metals.
In treating aneurysms it is common to place a number of coils within the aneruysm. The coils occlude the site by posing a physical barrier to blood flow and by promoting thrombus formation at the site.
Coils have typically been placed at the desired site within the vasculature using a catheter and a pusher. The site is first accessed by the catheter. In treating peripheral or neural conditions requiring occlusion, the sites are accessed with flexible, small diameter catheters such as those shown in U.S. Pat. Nos. 4,739,768 and 4,813,934. The catheter may be guided to the site through the use of guidewires (see U.S. Pat. No. 4,884,579) or by flow-directed means such as balloons placed at the distal end of the catheter. Use of guidewires involves the placement of relatively long, torqueable proximal wire sections within the catheter attached to more flexible distal end wire sections designed to be advanced across sharp bends at vessel junctions. The guidewire is visible using x-ray and allows a catheter to be placed in extremely tortuous vessels, even though surrounded by soft tissue such as the brain.
Once the site has been reached, the catheter lumen is cleared by removing the guidewire (if a guidewire has been used), and the coil is placed into the proximal open end of the catheter and advanced through the catheter with a pusher. Pushers are wires having a distal end that is adapted to engage and push the coil through the catheter lumen as the pusher is advanced through the catheter. When the coil reaches the distal end of the catheter, it is discharged from the catheter by the pusher into the vascular site. This technique of discharging the coil from the distal end of the catheter has a number of undesirable limitation. First, because of the plunging action of the pusher and the coil, the positioning of the coil at the site cannot be controlled to a fine degree of accuracy. Second, once the coil has left the catheter, it is difficult to reposition or retrieve the coil if such is desired.
Several techniques have been developed to enable more accurate placement of coils within a vessel. In one technique (U.S. Pat. No. 5,122,136, issued Jun. 16, 1992) the coil is bonded via a metal-to-metal joint to the distal end of the pusher. The pusher and coil are made of dissimilar metals. The coil-carrying pusher is advanced through the catheter to the site and a low electrical current is passed through the pusher-coil assembly. The current causes the joint between the pusher and the coil to be severed via electrolysis. The pusher may then be retracted leaving the detached coil at an exact position within the vessel. In addition to enabling more accurate coil placement, the electric current may facilitate thrombus formation at the coil site. The only perceived disadvantage of this method is that the electrolytic release of the coil requires a period of time so that rapid detachment of the coil from the pusher does not occur.
Another technique for detaching an embolic coil is shown in commonly assigned U.S. patent application Ser. No. 07/806,912. In that document, a coil having an enlarged portion is mated with a pusher having a keyway adapted to receive the enlarged portion of the coil in an interlocking relationship is covered by a coaxial member about the pusher and the coil. The coaxial member is movable by sliding the member axially. As the coaxial member is moved away from the junction where the coil's member engages the member of the keyway of the pusher, the coil disengages and the pusher is removed.
Another device for placement of coils is shown in commonly assigned U.S. patent application Ser. No. 07/806,898. This device includes a coil having a helical portion at one end and a pusher which is threaded to the inside of the helical coil by the use of a threaded section on the outside of the pusher. The device operates to release the coil by engaging the proximal end of the coil with a sleeve while the pusher is unthreaded. Once the pusher is free, the sleeve may be used to push the coil out into the treatment area.
Another method of placing an embolic coil is shown in U.S. Pat. No. 5,108,407. This patent shows the use of a device in which embolic coils are separated from the distal end of a catheter by the use of heat-releasable adhesive bonds. The coil adheres to the therapeutic device via a mounting connection using a heat sensitive adhesive. Laser energy is transferred through a fiber optic cable, which cable terminates at the connector. The connector becomes warm and releases the adhesive bond between the connection and the coil.
None of these disclosed devices suggest the use of an interlocking latch which allows an embolic coil to be precisely positioned and then released upon retraction of a control wire positioned within that latch.
SUMMARY OF THE INVENTION
This invention is a device for placing detachable coils within the vasculature of the human body so to occlude that site with the coils. The device includes a coil that carries an interlocking clasp at at least one end of the coil, preferably at its proximal end and a pusher (positioned within the catheter) which has a clasp at its distal end which interlocks with the clasp situated on the coil. The coils may have interlocking clasps at each end thereby allowing a number of coils to be strung together and yet individually released. A control wire passing through the catheter, the pusher assembly, the pusher clasp, and the coil clasp releases the coil as the control wire is retracted through axial passageways or openings provided in the two clasps.
Another portion of the invention is a method for occluding a selected vascular site comprising the steps of: (a) accessing the site with a distal end of a catheter; (b) advancing the assembly described above through the catheter with the coil clasp and the pusher clasp interlocked to a position out the end of the distal end of the catheter; (c) withdrawing the control wire from the two clasps to thereby detach the coil from the pusher; and (d) withdrawing the catheter and pusher from the vessel.
REFERENCES:
patent: 3334629 (1967-08-01), Cohn
patent: 3789841 (1974-02-01), Antoshkiw
patent: 4545390 (1985-10-01), Leary
patent: 4619274 (1986-10-01), Morrison
patent: 4739768 (1988-04-01), Engelson
patent: 4781177 (1988-11-01), Lebigot
patent: 4813934 (1989-03-01), Engelson et al.
patent: 4832055 (1989-05-01), Palestrant
patent: 4884579 (1989-12-01), Engelson
patent: 4957501 (1990-09-01), Lahille et al.
patent: 4994069 (1991-02-01), Richart et al.
patent: 5002556 (1991-03-01), Ishida et al.
pat
Dawson Glenn K.
Morrison & Foerster / LLP
Target Therapeutics Inc.
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