Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-04-21
2004-10-26
Hayes, Michael J. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S164050
Reexamination Certificate
active
06808509
ABSTRACT:
TECHNICAL FIELD
This relates to a medical device used to aid the introduction of another medical device into the body, and to methods of making and using such an introduction-aiding device. More particularly, this relates to an introducer system useful in the placement of a catheter into the body, and to methods of making and using such a system.
BACKGROUND INFORMATION
In general, sheaths used to facilitate the insertion of devices, such as catheters, into the body are known. A catheter (or other medical device) can be inserted, with the use of a known sheath, percutaneously into the body, and the sheath can be torn off after insertion of the catheter. Tearable sheaths generally are referred to as peelable sheaths. There are also non-peelable sheaths. Peelable sheaths generally are used to introduce devices which are left in (or at least partially within) the patient after the procedure is completed, and a dialysis catheter is one example of a medical device that is left within the patient after a placement procedure. Non-peelable sheaths generally are used when the introduced device is removed at the end of the procedure.
Known peelable sheaths generally include a hub located at the proximal end of the sheath, and the hub can be manually grasped and pulled apart to permit the longitudinal severance of the hub and the sheath thereby to allow the removal of the sheath and hub from about the catheter extending therethrough and from the body. Such known peelable sheath/hub combinations typically are provided with a dilator, and the whole package generally is referred to as a peelable introducer system or simply an introducer system. Introducer systems with non-peelable sheaths also are known.
Some introducer systems, with the dilator inserted into and through the peelable sheath/hub, are designed to be advanced over a guide wire that is indwelling in a vein, artery, or other body cavity of a medical patient. In general, whether or not used with a guide wire, an introducer system is a medical device for insertion into the body (e.g., into a vein, such as the jugular vein, of a patient). In one possible use, the introducer system is placed into a patient's vein in order to allow a flexible catheter to be placed later within the same vein through the sheath/hub of the introducer system after the dilator component of the introducer system is removed from the sheath/hub component.
Various types of peelable and non-peelable sheaths and introducer systems are available from Boston Scientific Corporation (Natick, Mass.) and other companies. Boston Scientific Corporation provides certain peelable sheaths and introducer systems in its commercially-available Vaxcel PICC kits.
Some known introducer systems include a valve to provide a seal around the catheter introduced through the sheath.
In general, known valved peelable introducer systems include two basic components: (1) a peel-away sheath/hub, where the hub is fixed to the proximal end of the sheath; and (2) a more rigid dilator that is sized to slide and fit snugly into a lumen extending through the sheath/hub. The hub generally is provided either as two identical separate halves (split along the length of the hub) or as a single unit with scoring or perforations on both sides along its length to allow the sheath hub to be broken into two identical separate halves. The dilator has a proximal hub portion and a longer tubular portion, and a passage typically extends through the dilator such that the dilator can be passed over a guide wire, for example. The tubular portion of the dilator is designed to extend through the sheath and the hub, and the proximal hub of the dilator can lock (e.g., via a luer lock) onto the hub of the sheath. A valve is incorporated into the hub of the sheath, and the dilator passes through this valve when the dilator is inserted into and through the sheath/hub. The valve typically is a thin, disk-like membrane.
In a typical use, a known valved introducer system (with the dilator inserted into the sheath/hub and through the valve) is inserted into a patient's vein (usually over a guide wire that is already in the vein) up to the sheath's hub such that most or all of the sheath is within the patient's vein and most of the dilator also is within the patient's vein, while the hubs of the sheath and the dilator are outside of the patient's body. The dilator is then removed from the sheath and from the patient's body. With the dilator removed, the valve is supposed to close and prevent air from entering the vein, which generally would happen if the passage through the sheath was open, because of negative pressure in the vein. The catheter (or other medical device) is now supposed to be inserted through the hub, valve, and sheath and thus into the patient's vein.
Known valved introducer systems generally have at least two issues. First, the valve may be too rigid to allow flexible devices, such as flexible catheters, to be inserted therethrough. Many catheters do not have enough column strength or rigidity to be passed through a tight valve. Second, if the valve is sufficiently flexible to allow a flexible catheter to be inserted therethrough, the valve may become malpositioned after the dilator is removed. That is, the valve may not close properly after removal of the dilator, and thus the danger of air entering the body or blood leaving the body is not avoided by use of the valve.
SUMMARY OF THE INVENTION
In general, the invention relates to a valved introducer sheath and associated methods of making and using such a sheath. The sheath can include a body portion and a proximal hub portion, with a passageway extending through the entire length of the sheath. The passageway is sized to receive a dilator that generally is more rigid than the body portion of the sheath. The elongated body portion of the sheath can be generally circular in cross-section and can have a first section that has a larger diameter than a second section. The body portion of the sheath could have one or more non-circular cross-sectional shapes. Along and within at least a portion of the passageway of the sheath, an elongated valve extends longitudinally. This elongated valve can be formed of foam or other compliant material that will allow the dilator to pass therethrough and that will form a seal therearound, and that will also close and form a reliable seal after the dilator is removed. The elongated valve of the invention also will allow a device more flexible than the dilator (e.g., a catheter) to be passed therethrough, and it will form a seal around such a device and then close and seal after the device is removed.
The valved introducer sheath of the invention can be “peelable” in that the body portion, hub, and valve can be manually broken apart, split, and peeled from around the device that extends therethrough. Once peeled from around the inserted device and removed from the body of the patient, the two halves of the now-split valved introducer sheath typically are discarded. In an alternative embodiment, the valved introducer sheath of the invention is not designed to be peelable.
The elongated valve provides better performance than existing valves in terms of at least the valved introducer sheath's ability to prevent reliably the influx of air (and/or the outflow of blood) as the dilator is being removed and after it is removed. The elongated valve of the invention can be opened and closed (by, for example, inserting and removing a dilator or other more flexible device such as a catheter) repeatedly without losing its ability to provide a reliable seal. Also, when the dilator is removed from the valve, and no medical device is present in the valve, the valve material is in an unstressed state.
In one aspect, the invention involves a method of producing a valved sheath. The sheath comprises a proximal hub portion, an elongated body portion extending distally from the proximal hub portion, and a passageway extending through the proximal hub and elongated body portions. A foam material is inj
DeSanto Matthew
Fay Kaplun & Marcin LLP
Hayes Michael J.
Sci-Med Life Systems, Inc.
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