All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
Intravascular catheters are widely used to deliver a variety of medical devices to a target location within a patient. Many catheters include an intermediate braided layer that provides sufficient strength to provide torque transmission and to prevent the catheter from kinking while being advanced within the patient. A catheter can also be visualized using radiographic techniques such as fluoroscopy by incorporating radiopaque materials into the materials. It is common to incorporate a larger percentage of radiopaque materials in the distal tip than in other regions of the catheter. In addition, the distal end of a catheter is frequently required to be more flexible than the rest of the catheter to prevent damage to the vasculature as it is advanced through the patient.
One method of cutting, or trimming, a catheter distal tip to a desired length is to place a pin inside of the distal end of the catheter and to simply roll the catheter on a level surface while pressing a sharp edge (e.g., a razor blade) into contact with the catheter. The cutting element thereby trims the distal end of the catheter to the specified length. After cutting the catheter, the pin is removed, a measurement is taken of the distal tip of the catheter, and the process is repeated if necessary to bring the distal tip dimension length into tolerance. This method can result in non-square cuts (cuts that are not perpendicular to the longitudinal axis of the catheter), debris remaining on the distal end, and inaccurate distal tip lengths.
What is needed is a cutting tool that can create a square cut while accurately and reliably cutting distal tips of catheters to a specified length without necessarily using visual markers as a datum for measurement.
One aspect of the invention is a catheter cutting system. The system includes a catheter cutting body including a channel defining a catheter cutting body bore adapted to receive an elongate member and a catheter therein and a cutting member guide adapted to receive a cutting member therethrough. The catheter includes a stop feature and the elongate member is adapted to be received within a first portion of the catheter. The elongate member is adapted to interact with the stop feature to determine that the catheter is disposed at a desired location within the catheter cutting body bore.
In some embodiments the elongate member is adapted to interact with the stop feature to determine that the stop feature is disposed at a desired location within the catheter cutting body bore.
In some embodiments the stop feature comprises a first portion of the catheter with a first resistance to expansion and a second portion of the catheter with a second resistance to expansion different than the first resistance to expansion. The first portion of the catheter can have a first diameter and the elongate member can have a second diameter larger than the first diameter. The stop feature can include an annular band which provides the second portion of the catheter with the second resistance to expansion which is greater than the first resistance to expansion.
In some embodiments the cutting member further comprises a first catheter rotation element and wherein the system further comprises a second catheter rotation element adapted to be fixed in position relative to the catheter. The first and second catheter rotation elements are adapted to mate such that the catheter is rotated as the cutting member is advanced through the cutting member guide. The first rotation element can be a rack and the second rotation element can be a gear.
In some embodiments the system further comprises a catheter clamp comprising a lumen therein adapted to slidingly receive the catheter, wherein the catheter clamp is adapted to be at least partially disposed within the catheter cutting body bore. The system can also include a catheter locking element adapted to lock the catheter in place relative to the catheter clamp.
In some embodiments the system also includes an elongate member locking element adapted to lock the elongate member in place at a predetermined location relative to the cutting member guide.
In some embodiments the catheter comprises an intermediate braid layer and wherein the stop feature, such as a solder band, is disposed at the distal end of the intermediate braid layer.
One aspect of the invention is a method of cutting a catheter. The method includes providing a catheter cutting body, wherein the catheter cutting body comprises a cutting body bore and a cutting member guide. The method includes positioning a first portion of an elongate member and a first portion of a catheter within the catheter cutting body bore, and wherein the catheter comprises a stop feature. The method includes positioning the first portion of the elongate member within the first portion of the catheter, engaging the elongate member and the stop feature, and advancing a cutting member comprising a cutting element through the cutting member guide to thereby cut the catheter with the cutting element.
In some embodiments cutting the catheter with the cutting element comprises cutting the catheter with the cutting element at a location that is determined by the axial position of the stop feature.
In some embodiments the first portion of the elongate member comprises a first end, and wherein positioning the first portion of the elongate member within the catheter cutting body bore comprises securing the first end of the elongate member within the catheter cutting body bore at a predetermined distance measured from an edge of the cutting member guide.
In some embodiments the method also includes securing the catheter in place relative to the elongate member before cutting the catheter with the cutting element.
In some embodiments advancing the cutting member through the cutting member guide comprises rotating the catheter. Rotating the catheter can include engaging a first catheter rotation element with a second catheter rotation element.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings wherein:
The invention relates generally to a cutting tool for cutting a catheter or other elongate medical delivery tool. More particularly, the invention relates to a cutting tool for accurately and reliably cutting a distal end or a proximal end of a catheter to a specified length without having to use visual markers as a datum for cut length measurement.
In one specific embodiment the clamp body bore is about 0.375 inches in diameter and the collet bore is between about 0.125 and 0.128 inches in diameter.
Cutting body 20 also includes cutting member guide 24 adapted to receive and engage cutting member 40. Cutting member 40 includes a cutting element 42 and rack 44, which is adapted to engage with gear 36 of catheter clamp 30. Cutting member guide 24 is sized and shaped to align and stabilize cutting member 40 as it is advanced through cutting member guide 24. Cutting element 42 (e.g., a razor blade) engages and cuts catheter 4.
Vertical support 12 includes channel defining bore 14 to receive cutting body 20 while cutting body 20 has bore 26 for receiving screw 16, which stabilizes cutting body 20 in vertical support 12.
Elongate member 50 is adapted to allow it be received within a distal tip of catheter 4 and is used in determining the location at which the catheter is cut by the cutting element, as is described in detail below. In one exemplary embodiment the elongate member has a diameter of about 0.101 inches and is about 2.00 inches in length. These are not intended to be limiting dimensions, and as described below the elongate member's dimensions can be varied based on the size of the catheter being cut and the location of the desired cut.
The inner and outer layers of the catheter are shown extending to distal end 208 of the catheter. The braid layer does not extend to the distal end such that distal tip portion 210 of the catheter is free of the braided material. The distal tip is therefore more flexible than the catheter proximal to the distal tip.
It may be beneficial to prevent the distal end of the braided material from unraveling. In addition, or alternatively, it may be beneficial to adhere the distal end of the braid layer (or other portions proximal to the distal end) to one or more layers of the catheter (e.g., the inner and/or outer layer).
In this embodiment stop feature 216 is the difference in resistance to radial expansion between a first portion of the catheter (i.e., the distal tip) and a second portion of the catheter (i.e., the section of the catheter in which band 212 is disposed). The difference in resistance is caused by band 212, which changes the flexibility of the two portions of the catheter.
In some embodiments a stop features as described herein can be referred to as a difference in a physical characteristic between a first portion of the catheter and a second portion of the catheter. For example, as described in the embodiment in
In some embodiments the stop feature can be referred to as a component or components of the catheter. For example, in the embodiment in
In general the stop features allows for the determination that the catheter has been positioned over the elongate member at a desired cutting location within the catheter cutting body bore.
The inner and outer layers of the catheter are shown extending to the distal end 61 of the catheter. The braid layer does not extend to the distal end such that distal tip 69 of the catheter is free of the braided material. The distal tip is therefore more flexible than the portion of the catheter proximal to the distal tip. Band 66 can be used to either prevent the braid from unraveling or to adhere the distal end of the braid layer to either the outer and/or inner layers. In one embodiment the braid is a metallic wire such as stainless steel and the band is a solder band which solders the distal end of the metallic wires to prevent them from unraveling. The band can be any material or mechanism which can prevent the braid from unraveling. For example without limitation, the attachment band can be any metallic material, any glue-like material, any mechanical linkage, etc.
In the embodiment shown in
The materials for the catheter cutting body, the clamp body, collet, and support can be any suitable polymeric material. In one specific embodiment the catheter cutting body, the clamp body, and collet are made from Delrin (Polyoxymethylene). In one specific embodiment the support is made from HDPE (polyethylene).
An exemplary method of cutting, or trimming, a catheter (or other elongate medical tool) using the exemplary cutting tool shown in
Next, catheter clamp body 32 (with catheter 4 disposed therein) is advanced into the proximal end of bore 22 in cutting body 20, as shown in the top view of
Catheter 4 is then advanced through the collet towards elongate member 50 until the distal end of the catheter is advanced over elongate member 50, as is shown in
Once the catheter is at the desired location and is secured in place, the catheter is then cut.
Cutting element holder and cutting element clamp can be made from, for example, a metallic material. In one specific embodiment they are made from aluminum (In this embodiment, rack 44 is not made of aluminum). The cutting element need only be able to cut through the layers of the catheter and can be, for example, a razor blade.
The cutting member is removed from the cutting body and the catheter clamp is removed from the cutting body. The catheter is then removed from the collet and the distal tip is accurately measured to ensure the distal tip length is within tolerance.
In use, first end 408 of elongate measuring member 402 is inserted into the cut distal tip of the catheter until elongate measuring member 402 interacts with the stop feature in the same manner as the elongate member described above. Elongate measuring member 402 and the elongate member have the same diameter. In this embodiment elongate measuring member 402 is advanced within the distal tip until it is snug and is met with increased resistance to continued advancement. Collar 404 is then slid along elongate measuring member 402 towards the distal tip of the catheter (not shown) until it contacts the distal tip of the catheter. Thumbscrew 406 is then tightened to secure collar 404 in place with respect to elongate measuring member 402. After this step the portion of elongate measuring member 402 within the distal tip of the catheter is shown in
It is important that elongate measuring member 402 has a diameter that is the same as the elongate member described above. This ensures that both elongate measuring member 402 and the elongate member will interact with the stop feature within the catheter in the same manner so that the length of portion 410 accurately reflects the length of the cut distal tip as closely as possible.
One advantage of the cutting tool is that it can accurately cut a catheter such that a distal tip has a specified length (within tolerance). The tool can also, or alternatively, be used to cut the proximal end of the catheter. As described herein, the cutting member includes a cutting element (e.g., razor blade). When the cutting member is positioned in cutting member guide 24, the cutting element (which is clamped between cutting element holder 100 and cutting element clamp 106; see
In some embodiments the position of the catheter within the cutting body bore can be determined in a non-mechanical manner. For example, the stop element can comprise a visual marker which can allow a user to determine that the catheter has been advanced to a desired location over the elongate member.
An additional advantage of the cutting tool described herein is the ability to make clean, square cuts. By stabilizing the catheter inside the collet and by aligning the cutting member with the cutting member guide, the cutting element can be disposed in contact with the catheter and advanced along a substantially straight line such that a substantially straight cut can be made in the catheter.
An additional advantage of the inventive cutting tool is that by incorporating a first and second rotation engagement elements (e.g., the rack and gear engagement), the catheter is rotated as the cutting element is advanced through the cutting member guide. Specifically, the catheter rotates in synchronization with the advancement of the cutting element. This creates a full revolution cut in the catheter and ensures that the entire cut made in the catheter is made with an unused and sharp portion of the cutting element (i.e., a portion of the cutting element that has not already cut another portion of the catheter). This ensures a dull portion of the cutting element is not used to cut any portion of the catheter, which could result in an incomplete cut. While the rack and gear system provides advantages for the cutting tool, it is envisioned that the cutting tool can be used without the rack and gear system. For example, in an alternative embodiment, a user could theoretically rotate the catheter clamp body (and thereby rotate the catheter) while the cutting member is advanced through the cutting member guide, although this could result in an incomplete cut.
While the cutting tool has been described herein as making a cut along the entire circumference of the catheter, it is envisioned that the cutting tool could be used to make cuts that do not make a full revolution. For example, a cut could be made in the catheter that extends ¾ of the way around the catheter. Alternatively, the cutting member guide could be at an angle other than 90 degrees to the longitudinal axis of the cutting body to allow for off-angle cuts to be made in the catheter. For example, while the cuts described herein are square cuts, the cutting tool can be adapted (by altering the angle of the cutting member guide) such that the cut is at an angle of 45 degrees, generating a bevel cut.
The cutting tool described herein has been described as being manually operated (the cutting member is manually advanced through the cutting member guide). The cutting tool can theoretically be automated such that the cutting member is automatically positioned and advanced through the cutting body to cut the catheter.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
This application is a divisional of U.S. application Ser. No. 12/189,527, filed Aug. 11, 2008, now U.S. Pat. No. 8,006,594; which application is incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | 12189527 | Aug 2008 | US |
Child | 13220444 | US |