Surgery – Instruments – Cutting – puncturing or piercing
Reexamination Certificate
1998-08-07
2001-06-26
Dawson, Glenn K. (Department: 3761)
Surgery
Instruments
Cutting, puncturing or piercing
C604S096010, C604S160000, C128S898000
Reexamination Certificate
active
06251119
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to inserting an introducer into a body tissue or cavity, including a patient's vascular system, and more particularly, to an introducer which provides access for medical devices, such as infusion catheters, pressure monitors, filters, balloon occluders, and/or cardioplegia catheters.
BACKGROUND OF THE INVENTION
A cannula is commonly used to introduce a catheter into a body cavity, such as a blood vessel. After the catheter has been inserted into the body cavity, the cannula, if left in place, may interfere with a surgical field. Removal of the cannula, therefore, is often desired. However, it is sometimes difficult to remove the cannula due to frequently enlarged proximal end of the catheter. This problem has been alleviated by splitable cannulas, which can be removed from a patient's blood vessel by separating into two parts, as described in U.S. Pat. Nos. 4,865,593, 5,104,388, and 5,318,542, all of which are incorporated herein by reference. Although the disclosed splitable cannulas are easy to remove, they all require an access mechanism to incise the blood vessel for insertion. Moreover, a distal end of a catheter, housed within the splitable cannula, often protrudes from the distal end of the cannula, and thus can be damaged by sometime calcific plaque of the blood vessel walls.
A need, therefore, exists for a cannula system which provides easy access, protection, and insertion of a medical device into a body tissue, and is removable by sliding.
SUMMARY OF THE INVENTION
The present invention provides a cannula system having the ability to incise a body tissue and allow insertion of a medical device housed within the cannula into the body tissue. The cannula system is a direct stick tear-away introducer which comprises an elongate intraluminal medical device having a proximal and a distal end. A sheath is disposed about the medical device and extends from the distal end of the medical device. A retractable blade is bonded to a distal end of the sheath, and a weakened region on the sheath extends longitudinally from the distal end to a proximal end of the sheath. The proximal end of the sheath may include a handle. The weakened region of the sheath may be a line of perforation. The sheath can be made from plastic, polycarbonate, or other suitable materials. The blade at the distal end of the sheath can be made of stainless steel, nitinol, or other suitable material. The blade may further have a lubricious coating with split to facilitate tear-away action. The sheath may extend from the distal end to the proximal end of the medical device. The medical device, therefore, is protected from damage during insertion.
The present invention also provides methods for introducing a medical device, including infusion catheters or cannulas, pressure monitors, balloon occluders, filters, or aspirators into a body tissue by providing a tear-away sheath, which is disposed about the medical device, and has a weakened region extending longitudinally and a blade bonded to its distal end. An incision in the body tissue is made using the blade bonded to the distal end of the sheath. The medical device is advanced into the body tissue through the incision, and the sheath and blade are removed by separating the sheath along its weakened region. In an alternative embodiment where the proximal end of a direct stick tear-away introducer has a handle, the sheath and blade can be removed by pulling on the handle. In this way, a medical device is introduced into a body tissue by the direct stick tear-away introducer, which can be easily removed and obviates the need for an access mechanism.
REFERENCES:
patent: 3651807 (1972-03-01), Huggins
patent: 5114401 (1992-05-01), Stuart et al.
patent: 5167634 (1992-12-01), Corrigan et al.
patent: 5318542 (1994-06-01), Hirsch et al.
patent: 5951518 (1999-09-01), Licata et al.
Dawson Glenn K.
Embol-X Inc.
Lyon & Lyon LLP
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