Patent Application
20160271377
The present disclosure relates to catheters and methods of using the same, and more specifically, to a catheter for draining a body cavity.
Catheters may be used for many purposes including draining fluids, such as urine or bile, from a body cavity. A drainage catheter may be inserted into the body through an orifice or the skin until it reaches a cavity in the body where fluid exists. Drainage catheters commonly have a proximal end portion and a distal end portion with an anchor at the distal end portion to secure the drainage catheter in the desired cavity in the body. These anchors can be referred to as a Malecot. Malecots are commonly used as a bladder or kidney anchoring mechanisms in urinary drainage catheters and nephrostomy tubes.
This type of anchor is commonly made up of at least two wings or arms, which may be continuous with the rest of the catheter and may be made from the same material. These wings or arms are typically biased toward an expanded position, so that when no force is applied to the wings or arms, they can potentially hold the drainage catheter in place in a body cavity. While drainage catheters can be made of several materials, often, a thick-walled material must be used in order for the wings or arms to possess enough shape memory to function as an effective anchor.
A first embodiment of the disclosure is provided. The embodiment includes a drainage catheter with a Malecot-type anchoring mechanism and a spring that is incorporated into the Malecot-type anchoring mechanism. The drainage catheter may be a long narrow tube or shaft having an outer diameter and a smaller inner diameter. The drainage catheter may also have an inner lumen adapted to allow fluid to flow therethrough. The drainage catheter may also have a proximal end portion and a distal end portion. The drainage catheter may also be used in nephrostomy tubes, biliary drainage catheters, and urinary drainage catheters.
At the distal end portion there may be a Malecot-type anchoring mechanism having a top portion and a bottom portion. The Malecot-type anchoring mechanism may also consist of a plurality of expandable wings or arms which are biased toward a first radially expanded open position and are moveable toward a second radially compressed insertion position. The Malecot-type anchoring mechanism may also comprise a spring that is connected to the top portion and the bottom portion of the Malecot-type anchoring mechanism.
The spring may be biased toward a compressed position which may put an inward force on the Malecot-type anchoring mechanism so that the top portion and the bottom portion are urged toward one another and the plurality of expandable wings or arms are further urged in the first radially expanded open position. The spring may also be urged toward an expanded position by an external force to allow the Malecot-type anchoring mechanism to be moved toward a radially compressed insertion position. After the external force is removed, the spring may be formed from a superelastic material that will allow it to return to its original compressed position. Using a spring attached to the Malecot anchoring device, the drainage catheter can be made of a thinner walled catheter material and achieve the same Malecot shape memory as a thicker walled catheter material without a spring.
Advantages of the disclosed devices will become more apparent to those skilled in the art from the following description of embodiments that have been shown and described by way of illustration. As will be realized, other and different embodiments are contemplated, and the disclosed details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.
Drainage catheters are designed to remove undesired fluids from body cavities such as the kidney and bladder. The drainage catheters may be a long narrow tube or shaft having an outer diameter and a smaller inner diameter. An anchoring mechanism may be provided at or proximate to the distal end portion of the tube. The anchoring mechanism may be a malecot having a plurality of expandable wings or arms that are biased toward an expanded position. The plurality of expandable wings or arms may be from an elastic material, such as a superelastic material that allows the material to return to its original shape after an external force has caused a deformation in the plurality of expandable wings or arms is removed.
Sometimes, certain materials fail to return to their original shape after removal of an external force if the elasticity of the material is not strong enough initially or if the material has weakened over time. If the anchoring mechanism does not have a sufficient elasticity, it can often fail to effectively anchor the drainage catheter in place in a body cavity. If a material is too thick, it can cause complications with insertion and removal of the drainage catheter, which can also create a dangerous or uncomfortable situation for a patient.
One embodiment of a typical drainage catheter 100 for use in draining fluids from a body cavity is depicted in
The malecot type anchoring mechanism 200 may include a plurality of arms 201, such as 2, 4, 6, 8, or any number of arms that may be appropriate for the necessary anchoring of the tube 100 in place (as will be readily understood or calculated by one of ordinary skill in the art with a thorough review of this specification and the clinical use of the device). The arms 201 may be formed to be biased into an extended position, and may be capable of being urged into a smaller insertion position. In some embodiments, the plurality of arms 201 collectively form an outer diameter that is significantly larger than the outer diameter of the central portion 103 of the tube 300 when the arms 201 are in the expanded position. For example, the outer diameter of the plurality of arms 201 in the expanded configuration may be referenced as a ratio of the diameter of the central portion of the tube 300, and may be such ratios as 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, and 10:1 (including all ratios in this range that are not whole numbers, e.g. 4.5:1) or other ratios that may be clinically suitable. One of ordinary skill in the art, after a thorough review of this specification will contemplate that other ratios may be possible and are within the scope of this disclosure.
Turning now to
In one embodiment of the disclosure, the plurality of expandable wings or arms 201 may be biased toward a first radially expanded open position and may be moveable toward a second radially compressed insertion position with the arms 201 collectively compressed into an outer diameter that is less than the outer diameter when the arms 201 are in the expanded position. In some embodiments, when the arms 201 are compressed into the insertion position, the arms 201 collectively form the same outer diameter as the outer diameter of the central portion 103 of the tube 300, or in other embodiments, the outer diameter of the arms 201 may be within 5, 10, 15, 20, or 25 percent of the outer diameter of the central portion 103.
In some embodiments, the plurality of expandable wings or arms 201 may be elastic and may be trained or configured to be urged toward the radially expanded open position due to the construction of the arms 201. In some embodiments, the arms may be formed from polymers or plastics that may be formed with a biasing force toward the radially expanded open position. In some embodiments, the arms 201 may include a superelastic wire or wires that are trained to extend toward the radially expanded open position, such as after an external force that urged the arms 201 toward the insertion position is removed.
The spring 202 also may be formed from an elastic material, such as superelastic material, such as nitinol including various alloys of nitinol. By connecting to the Malecot-type anchoring mechanism 200 at the top portion 220 and the bottom portion 210 of the spring, the spring 202 may be urged in compression (i.e. the spring 202 is biased to compress along its length), urging the top portion 220 and the bottom portion 210 toward one another. This biasing force of the spring 202 may further assist the plurality of expandable wings or arms 201 in returning toward their original positions after an external force that urged the malecot arms 201 to the insertion position is removed.
As best shown in
One embodiment of a typical drainage catheter 100 for use in draining fluids from a body cavity in an insertion position is depicted in
When the external force F is removed (or in other embodiments when the inward force upon the arms 201 is removed), the plurality of wings or arms 201 may return to or toward the first radially expanded open position based upon the outer biasing force of the arms 201 as further urged by the spring 202.
While the preferred embodiments of the disclosure have been described, it should be understood that the disclosure is not so limited and modifications may be made without departing from the invention. The scope of the invention is defined by the appended claims, and all devices that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.
This application claims priority from U.S. Provisional Application No. 62/135,383 filed on Mar. 19, 2015, the entirety of which is hereby fully incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62135383 | Mar 2015 | US |
