Surgery – Radioactive substance applied to body for therapy – Radioactive substance placed within body
Reexamination Certificate
1999-04-28
2001-02-20
O'Connor, Cary (Department: 3736)
Surgery
Radioactive substance applied to body for therapy
Radioactive substance placed within body
C600S001000
Reexamination Certificate
active
06190303
ABSTRACT:
TECHNICAL FIELD
The present invention relates, generally, to shield assemblies for radioactive devices and, more particularly, to radiation shields for radioactive stents and delivery catheters.
BACKGROUND OF THE INVENTION
Percutaneous Transluminal Angioplasty (PTA) is a medical procedure for widening a stenosis or constriction of a bodily passage. The most common application is to widen the passage of a blood vessel, such as an artery, which has been constricted by the build-up of cholesterol fats or atherosclerotic plaque. When this medical procedure is applied to a coronary artery, it is referred to as Percutaneous Transluminal Coronary Angioplasty (PTCA).
Typically, a tip mounted balloon of a balloon catheter is advanced over a guidewire to the stenosis. Once the balloon catheter is properly positioned, the balloon is inflated to compress the plaque against the vessel walls and widen the stenosis. Problems occur, however, when the dilatation of the occlusion forms fissures, flaps and/or dissections which may ultimately cause reclosure or restenosis of the vessel.
To maintain vessel patency and/or strengthen the area undergoing angioplasty or other treatment, an intravascular prosthesis may be employed. These devices are usually introduced percutaneously, transported transluminally and positioned at a desired location within the widened stenosis of the patient. One form of an intravascular prosthesis is a radially expandable stent device which is typically positioned at the tip of a balloon delivery catheter in a crimped condition. When the tip of the delivery catheter apparatus and the crimped stent are properly positioned at the desired location or the stenosis, the balloon is expanded to implant the stent in the widened vessel. In some instances, expansion of the balloon portion of the delivery catheter can simultaneously compress the plaque at that location and expand the stent to its proper implantation size. The balloon portion of the catheter is then deflated and withdrawn from the vessel, leaving the implanted radioactive stent as a permanent scaffold and as a deterrent to tissue growth in order to reduce the chance of restenosis.
More recently, these stents have been embedded or implanted with radioisotopes so that they emit predictable amounts of radiation into the widened vessel and immediate surrounding area. The nature of these radioactive devices is that regrowth of the tissue can be reduced by the radiation, and effect which is highly beneficial in preventing restenosis of the vessel.
Although these radioactive stents only emit relatively low levels of radiation, direct contact with the stent by physicians, laboratory technicians, and other personnel should be avoided. As a result, shielding devices
10
such as those shown in
FIGS. 1A and 1B
have been developed to enable the safe transportation and handling of radioactive stent
11
and/or a stent delivery catheter apparatus
12
. Typical of these shields devices
10
is disclosed in U.S. Pat. No. 5,605,530 entitled “System for Safe Implantation of Radioisotope Stents” which is incorporated by reference in its entirety.
These radioactive shield devices
10
typically include one piece main body portions
13
having longitudinally extending central lumens
15
therethrough. Positioned in these lumens
15
in a retracted condition (
FIG. 1A
) are the stent delivery catheter apparatus
12
and crimped radioactive stent
11
for shielding thereof. Accordingly, this one-piece configuration enables safe transportation and handling of the radioactive stent before being inserted into the vessel.
The radiation shield device
10
further preferably includes a distal proboscis
16
and a proximal threaded section
17
which operates as a Tuohy-Borst fitting
19
onto which a nut
18
can be screwed. When the expandable balloon
20
of the delivery catheter and the distal mounted radioactive stent
11
are retracted in the central lumen
15
of the shield device
10
(FIG.
1
A), a shield nut
18
may be tightened down on proximal threaded section
17
, thereby frictionally coupling the stent delivery catheter apparatus
12
therein.
To insert the stent delivery catheter apparatus
12
and stent
11
into a vessel (not shown), the proboscis
16
of the shield device
10
is preferably inserted into another Tuohy-Borst fitting
21
of a guiding catheter. This union may be provided by a Y-adapter
22
having an adapter nut
23
tightened to the threaded end
24
to functionally couple and fluid seal the radiation shield device to the Y-adapter. Subsequently, the proximal shield nut
18
may be loosened to enable the mounted stent
11
and the delivery catheter apparatus
12
to be forwardly advanced (
FIG. 1B
) into a passage
25
of the Y-adapter
22
and into the vessel as a unit.
While this one-piece shield device is most adequate to shield personnel from radiation exposure from the radioactive stent, several problems are inherent in the design. For example, when the radiation shield device
10
is mounted to the Y-adapter
22
, and the delivery catheter is slideably inserted through the central lumen
15
of the shield device and the passage
25
of the Y-adapter, the radiation shield device cannot be removed or separated from the delivery catheter apparatus
12
since the diameter of the central lumen is not sufficiently large to enable the proximal manipulating end of the catheter apparatus (not shown) to slide therethrough. Consequently, the depth of insertion of the delivery catheter is limited to the proximal end of the radiation shield device (i.e., the Tuohy-Borst fitting
19
) rather than the proximal end of the Y-adapter
22
(i.e., the Tuohy-Borst fitting
21
). Therefore, the useable length of the catheter
12
is decreased. Increasing the length of the catheter apparatus to compensate for the decrease of insertion depth may be problematic since any increase in length may incrementally reduce the ability to precisely control the stent placement. This configuration also limits the physicians choice of delivery catheters to only those provided with the stent.
Moreover, even should a length increase be unnecessary, manipulation of the catheter apparatus is still more difficult since the surgeon must now control the catheter from relatively cumbersome shield device as compared to the smaller proximal end of the Y-adapter. This is especially true in instances where the shield device
10
has been decoupled from the Y-adapter during stent deployment. The mere weight and bulkiness of the shield device
10
dangling from the catheter apparatus significantly reduces maneuverability and manipulation of the catheter. In fact, in some instances, care must be observed so that the weight of the shield device
10
does not retract the stent assembly from the vessel.
Another problem associated with this arrangement is that after the stent delivery catheter apparatus
12
and the mounted radioactive stent
11
have been passed through the central lumen
15
of the shield device
10
into the passage of the Y-adapter, it is difficult to reinsert the catheter apparatus and the stent back into the central lumen of the shield device
10
, should this be necessary to abort the deployment procedure. Therefore, there is a need to enable removal of the radiation shield device from the delivery catheter apparatus during deployment of the stent.
SUMMARY OF THE INVENTION
To achieve the foregoing, the present invention relates to a shield assembly for a deformable stent mounted onto a deployment portion of a delivery apparatus. The shield assembly includes a relatively thin, elongated tube member having a wall defining a receiving passage formed and dimensioned for axial receipt of the stent mounted onto the deployment portion therein. This arrangement substantially prevents direct contact with the stent. The shield assembly further includes removal structure cooperating with the wall of the tube member for longitudinal severing thereof to enable selective removal of the tube member from the delivery apparatus for deployment use the
Campbell Thomas H.
Glenn Richard A.
Turnlund Todd H.
Beyer Weaver & Thomas LLP
IsoStent, Inc.
Natnithithadha Navin
O'Connor Cary
LandOfFree
Shield assembly with removable inner-tube apparatus for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Shield assembly with removable inner-tube apparatus for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Shield assembly with removable inner-tube apparatus for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2579124