Surgery – Instruments – Internal pressure applicator
Patent
1999-01-13
2000-08-22
Buiz, Michael
Surgery
Instruments
Internal pressure applicator
606185, A61M 2900
Patent
active
061065404
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a body vessel or cavity dilator and to an introducer assembly for dilating a vessel or cavity and introducing a sheath therein.
BACKGROUND ART
There are many applications where it is necessary to insert a sheath or catheter into a body cavity or vessel. One means of facilitating the insertion of a sheath is to use a dilator fitted with a sheath that moves into the cavity or vessel and is then withdrawn leaving the sheath in place.
The placement of prosthetic devices, such as stents and grafts, intraluminally and the conduct of minimally invasive operative procedures has grown dramatically in recent years. Where, for example, an intraluminal graft is adapted for insertion into a patient to achieve bridging and occlusion of an aortic aneurysm, a sheath of sufficient diameter and adapted to assist with the delivery of the prosthetic device needs to be inserted into and through the femoral and associated iliac artery.
In many persons, the femoral artery, in passing over the pelvis, takes a quite tortuous path that can impede the passage of a catheter of sufficient width and stiffness and in turn also impede the travel of a graft through the catheter.
The present invention is directed to a device that alleviates the problem posed by such tortuous vessels.
STATEMENT OF INVENTION
According to a first aspect, the present invention comprises a resiliently flexible dilator for a bodily vessel, the dilator tapering towards one end to facilitate insertion of the dilator into the vessel and having a transition zone having a first end proximate the said one end and a second end distal the said one end, the physical properties of the dilator in the transition zone being such that the flexibility of the dilator at the second end of the transition zone is less than the flexibility of the dilator at the first end of the transition zone.
In one embodiment, the transition zone of the dilator comprises no more than half the length of the dilator, and more preferably no more than a quarter the length of the dilator. The resilient flexibility of the remainder of the dilator, apart from the transition zone, is preferably substantially constant along its length.
The dilator can taper along its whole length or just a portion adjacent the said one end. The tapering portion of the dilator towards one end can comprise a frusto-conical portion or hemispherical portion adjacent the said one end. The transition zone of the dilator can further overlap or be separate from the tapering portion of the dilator.
In one embodiment, the dilator is comprised of a polymeric or elastomeric material. The change in flexibility in the transition zone can be provided by an increase in cross-linking of the polymeric or elastomeric material along the dilator.
In another embodiment, the transition zone comprises an inner relatively stiff core of material having a tapered portion, with at least the tapered portion being surrounded by an outer layer of relatively resiliently flexible material that extends beyond the tapering portion of the core material so that the dilator undergoes a gradual decrease in flexibility in the region of the tapering portion of the core. In this embodiment, the dilator adjacent the said one end of the dilator can be formed from the relatively resiliently flexible material. This embodiment of the dilator can be fabricated by a co-extrusion of the inner core and the outer layer. The core can be fabricated from a 90/10 high density polypropylene and the outer layer from an ethylene-vinyl acetate (EVA) copolymer. Both the core and outer layer call include a barium sulfate component (eg: approximately 10%) to make the same radiopaque.
In a preferred embodiment, the dilator has a longitudinally extending axial bore to receive a guidewire already inserted through a vessel, and has a sheath disposed thereabout so that when the dilator is withdrawn the sheath is left in place in the vessel.
The flexibility of the said one end of the dilator is preferably substantially similar
REFERENCES:
patent: 5254107 (1993-10-01), Soltesz
patent: 5569218 (1996-10-01), Berg
White Geoffrey H.
Yu Weiyun
Baxter International Inc.
Buiz Michael
Canter B. M.
Gluck Peter Jon
Goldberg Jonathan D.
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