Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1998-07-23
2001-09-25
Seidel, Richard K. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S264000, C604S523000, C604S508000
Reexamination Certificate
active
06293927
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an implantable surgical device and method of delivery. More specifically, this invention provides a multiple lumen catheter and separable sheath for delivering the catheter to the arteriovenous system in order to perform hemodialysis.
BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART
Multiple lumen catheters which are surgically implanted into the body and used for dialysis are known, being disclosed in U.S. Pat. Nos. 5,405,320 and 5,509,897 to Twardowski et al. and U.S. Pat. No. 5,509,900 to Kirkman.
The multiple lumen catheters disclosed in '320 and '897 are three dimensional in form, specifically calling for catheter portions which are substantially perpendicular to remaining, planar portions. Such multiple lumen catheters have been promoted as being allegedly permanent devices providing access to a patient arteriovenous system for hemodialysis but have proven to have significant disadvantages. The three dimensional character of these catheters inherently serves to stress the vessels of the arteriovenous system in which the catheter resides, thereby shortening useful life of the catheter.
The catheter disclosed in '900 is intended and designed to be retained at a specific spot within a blood vessel by an anchoring tip which serves to retain the catheter with respect to the wall of the blood vessel. The anchoring tip, by fixing the catheter in place and not permitting relative movement of the vessel vis-a-vis the catheter, creates a potential for rupture of the vessel or for collection of thrombolytic material about the positioning means, both of which are undesirable.
With the increasing use of dialysis therapy and ever a increasing expected lives of dialysis patients, the need exists for a permanent dialysis catheter which can be surgically implanted within the patient's blood vessels, and causing minimum trauma to the patient on a continuing basis. The need further exists for such a catheter which minimizes the possible collection of thrombolytic material at the inlet and outlet orifices of the catheter while keeping the inlet and outlet orifices remote from the wall of the vessel in which the catheter resides, thereby promoting high flow hemodialysis with relatively low fluid pressures, resulting in minimal patient connection time to the dialysis machine, longer catheter useful life and reduced possibility of catheter dysfunction as a result of malpositioning.
Surgical cannulas or “sheaths” are typically utilized by medical personnel to establish transcutaneous access channels from a first percutaneous location to a second subcutaneous location. The access channel provides a conduit for the delivery of pharmaceutical products, removal of subcutaneous sample tissue and fluid, as well as the coaxial passage of instrumentation such as catheters and the like.
In surgical procedures which require only temporary use of a sheath conduit, “peel-away” style sheaths are utilized. The peel-away sheath has lines of weakness extending about opposing sides of its longitudinal length such that removal of the sheath can be accomplished by applying a separating force or “peeling” the wall sections downwardly from the transcutaneous end by way of integral pull tabs located thereon, to cause a linear tearing of the sheath material causing the “peeling” or failure of the A material. In this way, the sheath can be removed from the patient without removing the instruments positioned within the sheath channel.
However, application of the peeling force to the sheath wall sections tends to aggravate and/or enlarge the incision in the region of the sheath as force is applied downwardly into the incision. Stressing of the incision is particularly problematic in irregularly manufactured sheaths having uneven wall thickness along the lines of weakness. The wall thickness may also cause kinking when attempting to insert a product or device through its thin walls. Moreover, the peeling force tends to lift instruments within the sheath pathway upwardly from the patient.
SUMMARY OF THE INVENTION
In one of its aspects, this invention provides a stationary central tunnel dialysis catheter including a planar axially elongated sinuous tabular member having a plurality of axially extending lumens formed therein. At least a part of the tubular member may be of predetermined two-dimensional, generally M-shape in order to substantially match the human left side venous anatomy. The M-shape includes portions of relative straightness connected by curved portions and is adapted to fit in a preselected body lumen in the anatomical region of interest. The M-shaped part of the tubular member is preferably deformable, resiliently returning to the predetermined two-dimensional M-shaped after deformative surgical implantation in the patient by way of a separable sheath delivery system. The M-shape part of the tubular member preferably has at least two lumens, with each having at least one aperture separated from the other but proximate the extremity of a leg of the M for through passage of fluid during dialysis; the apertures are axially displaced one from another. In the M-shape configuration of the catheter, there are preferably at least four portions of relative straightness.
In yet another of its aspects, this invention provides a stationary central tunnel dialysis catheter including a planar axially elongated sinuous tubular member having a plurality of axially extending lumens formed therein. At least a part of the tubular member preferably has a predetermined two-dimensional shape substantially matching an anatomical central tunnel region of interest and preferably includes at least two portions of relative straightness connected by a curved portions, fitting a preselected body lumen in the anatomical region of interest. The tubular member is preferably deformable, resiliently returning to its predetermined two-dimensional shape after deformative surgical implantation in the patient.
In the part of the tubular member having predetermined shape, at least two of the lumens each have at least one aperture for through passage of fluid during dialysis with the apertures being axially displaced one from another along the tubular member.
The catheter may further optionally but preferably include a flexible sheath complementally surrounding at least the part of the tubular member having predetermined two-dimensional shape to facilitate delivery and aseptic protection thereof with the sheath being removable therefrom in situ when the tubular member has been positioned within the preselected lumen. When the flexible sheath is included as a part of the catheter, ripcord means preferably extends along the length of the tubular member for rupturing the sheath in the vicinity of an axial extremity of the tubular member proximate the apertures. The ripcord means extends in response to preferably manual force preferably applied to a portion of the ripcord extending from a body of the patient in whom the catheter has been implanted. The ripcord may be embedded in the tubular wall or may be inside the sheath or may be imbedded in the sheath.
This invention additionally provides a separable surgical sheath wherein the sheath is removed from the transcutaneous location and readily separated from the catheter positioned therein by percutaneously initiating separation of a length of the conduit from a first conduit wall location to a second conduit wall location. This allows for remote sheath removal and for the catheter to be delivered along with the sheath as a package, facilitating passage of the device into the patient's arteriovenous system for hemodialysis.
The sheath in accordance with the invention includes a conduit preferably having distal and proximate ends and a line of weakness extending about the longitudinal length of the conduit. The line of weakness is ruptured by a separation control. The conduit has a pre-formed line of weakness traversing its longitudinal length. The device preferably utilizes an embedded suture to define the line
Maynard Jennifer
Rex Medical
Seidel Richard K.
LandOfFree
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