Drainage Catheter With Anti-clogging Means

Abstract

A physiological drainage catheter comprising an elongated tube with a central axis and a peripheral wall surrounding it. A port passes through the wall to the passage for the purpose of draining fluid from the region surrounding the tube. A peripheral cuff surrounds the wall and is fastened thereto on each side of the port, the cuff ballooning away from the wall to leave a cavity therebetween. The cuff is made of a flexible openpore silicone rubber sponge which provides a large number of restricted, but continuous, passages from outside of the cuff to the cavity, and an increased surface area thereby to screen or filter fluid which reaches the port from regions to be drained outside the cuff to minimize clogging, and by its increased surface area to decrease the possibility of being closed by abutment with surrounding tissue.

Description

This invention relates to a physiological drainage catheter.

Drainage catheters are widely used in various applications in the human body, perhaps the best known example being the drainage of fluid from within the cranium of a person afflicted with hydrocephalus. A problem frequently encountered in the use of catheters in the drainage of body fluids is that the body fluids are not clear solutions, but instead, carry with them particulate matter which tends to clog the drainage means and thereby destroy the efficacy of the device. It is an object of this invention to provide a catheter which screens or filters the fluids in such a manner as to prevent clogging of the device and to provide a large screening area compared to that which is otherwise obtainable, simply by perforating the walls of a tube.

Another problem is the closing of inlet ports by abutment of surrounding tissue. This device increases the perforated area over that made available in the prior art, and thereby alleviates this problem.

A physiological drainage catheter according to this invention comprises an elongated tube having a peripheral wall surrounding an internal central passage extending along a central axis. At least one entry port passes through the wall to the passage, and a peripheral cuff surrounds the wall and is fastened thereto on each side of the port. The cuff balloons away from the wall so as to leave a cavity therebetween, and thereby provides a large screening area which also reduces the risk of closure by surrounding tissue. The cuff is made of a flexible openpore silicone rubber sponge whereby to provide a large number of restricted passages from outside the cuff to the cavity, thus to screen or filter fluid which reaches the port from the regions to be drained outside of the cuff.

According to a preferred, but optional, feature of the invention, there is a plurality of said inlet ports, and the cuff is attached to the outer wall of the tube so as to form a pair of axially spaced apart peripheral seals.

According to still another preferred, but optional, feature of the invention, the tube terminates at one end at a stiffened, laterally enlarged tip which forms an external shoulder, one end of the cuff abutting the shoulder.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:

FIG. 1 shows the presently preferred embodiment of the invention installed in the head of a child suffering from hydrocephalus;

FIG. 2 is a fragmentary axial cross-section of the presently preferred embodiment of the invention; and

FIG. 3 is a cross-section taken at line 3--3 of FIG. 2.

FIG. 1 shows a drainage system 10 installed in the cranium 11 of a child. The child's brain 12 is shown in general schematic notation, and a catheter 13 according to the invention is thrust through a hole 14 formed in the skull into the ventricles of the brain to drain excess fluid therefrom. A pump 15 of the general type shown in Schulte U.S. Pat. No. 3,111,125 issued Nov. 19, 1963, is placed against the outside of the skull beneath the scalp, and accepts fluid from the physiological drainage catheter and discharges it into a shunt tube 16 which is only incompletely shown, but which leads to some other region of the body, such as the heart, to dispose of the excess fluid. A shunt tube of this general classification is shown in Heyer U.S. Pat. No. 3,020,913 issued Feb. 13, 1962. This shunt tube customarily includes a check valve means, and the pump itself similarly comprises a check valve means, the combination assuring a unidirectional flow from the ventricles of the brain to the region in which the fluid is discharged. The pump, which is optional, also provides pumping means.

It is a problem in the ailment of hydrocephalus that drainage of the ventricular fluid does not take place normally, and the fluid pressure builds up and distends the head of the child, compressing the brain and rendering the child an invalid, frequently an idiot. It often is a fatal ailment. Relief of this pressure by drainage of the fluid has resulted in profound improvement in many of these children, and thousands of them are now alive and normal who otherwise would have been dead or living in idiocy.

One of the problems faced in this drainage is the particulate matter discharged from the brain which clogs the inlet ports of commonly known catheters. Numerous attempts have been made to provide screening means which themselves do not clog, and it is an object of this invention to provide one such which substantially improves the capabilities of such a device. It is a further objective to reduce the risk of closure of the catheter by abutting tissue.

A physiological drainage catheter, according to this invention, includes as elongated tube 20 which has a central passage 21 extending along a central axis 22. A plurality of entry ports 23 extends through the peripheral wall 24 of the tube so as to enable the fluid to pass to the central passage, thence to be drained.

According to a preferred, but optional, feature of the invention, a tip 30 is formed which is laterally enlarged relative to the outer wall of the elongated tube so as to form an external shoulder 31. A tapered nose 32 is provided to aid in insertion of the device. The tip is stiffened either by inherently increasing the hardness of the material of which this portion of the tube is made, or simply by providing an enlarged solid body without the intrusion of a central port. Either technique is satisfactory.

A porous cuff 35 is formed peripherally around the tube and is joined at two fully peripheral seams 36, 37 on opposite sides of the plurality of entry ports. In the preferred embodiment, when shoulder 31 is provided seam 36 is contiguous to shoulder 31. The cuff balloons away from the wall so as to form a cavity 38. This is done by using a balloon with greater inner diameter than the outer diameter of the tube, and by spacing the seams closer together than the sides of the cuff would be in its undistorted condition. The cuff is flexible, and the shape of the cavity will change in response to external forces. However, it is unlikely that all of the entry ports in the tube would be shrouded at any time by the cuff, so that free flow from the cavity to the passage is generally provided for. The ballooning provides a large surface area which folds and distorts, and is likely always to provide a surface somewhere that is open to flow, and not abutted by surrounding tissue.

It is customary practice to formulate the entire system out of medical grade silicone rubber because this is not reactive with tissue. Therefore, the tube will be of silicone rubber formulated according to the desired flexural properties. The cuff will be made of a silicone rubber foam or sponge (these terms being used interchangeably) which is open-cell in the sense that the cells communicate with one another and provide a large number of passageways through the wall of the cuff. The cuff is therefore porous over its entire surface and provides screening or filtering means.

It will thereby be seen that the cuff provides a very large number of alternate passages for the fluid which are unlikely, because of their large number, all to be covered or clogged at once as opposed to the tendency in standard catheters for the relatively few numbers of entry ports to clog up.

Similarly, it will be noted that the cuff region is placed within the ventricle of the brain where the brain may press back against it. Such restoration of the ventricles has in the past clogged the relatively few entry ports, but this type of covering or clogging is less likely to occur in view of the very large area in which fluid flow openings are available with the use of this cuff.

There is therefore provided a catheter suitable for use in drainage of a region of the human body in which the the risk exist of clogging both by particulate matter and by abutment contact of surrounding tissue, in which the risk are reduced by the provision of a flexible, large-area porous member that serves as an effective enlargement of the access means to the drainage tube, and which by its design, effectively precludes any chance that the tube will ever be completely stopped up, either by particulate matter or by mechanical contact.

This invention is not to be limited by the embodiment shown in the drawings and described in the description, which is given by way of example and not of limitation, but only in accordance with the scope of the intended claims.

Claims

I claim:

1. A drainage catheter comprising: an elongated tube having a central axis and a peripheral outer wall, an axial passage extending along the central axis, and at least one entry port passing through the wall to the passage; and a peripheral cuff encircling the wall and fastened thereto at axially spaced apart locations on opposite sides of the port, the cuff ballooning away from the wall to leave a cavity therebetween, the cuff being inherently flexible and resiliently deformable, and made of a flexible, open-pore silicone rubber sponge whereby to provide many restricted but continuous passages from outside of the cuff to the cavity, thereby rendering the cuff permeable to fluid, and uninflatable, the ballooning being caused by the inherent shape of the cuff as attached to the tube when otherwise unstressed, the cuff being deformable by contact with surrounding tissue.

2. A physiological drainage catheter according to claim 1 in which the cuff makes a full peripheral seam with the wall on each side of the entry port.

3. A physiological drainage catheter according to claim 2 in which there is provided a plurality of said entry ports, the seams being formed on opposite sides of the said plurality of entry ports.

4. A physiological drainage catheter according to claim 1 in which the tube terminates in abutment at one of its ends against a shoulder formed on a laterally-enlarged tip.