WO2015132435A1

WO2015132435A1 - Catheter for treating hydrocephalus

Info

Publication number: WO2015132435A1
Application number: PCT/ES2015/070146
Authority: WO
Inventors: Jose Maria AMIGO GARCIA; Angel Gimenez Pastor; Olga Pellicer Porcar; Jose VALERO CUADRA; Marcelo Galarza
Original assignee: Universidad Miguel Hernandez De Elche; Fundacion Para La Formacion E Investigación Sanitaria En La Region De Murcia
Priority date: 2014-03-06
Filing date: 2015-03-02
Publication date: 2015-09-11
Also published as: ES2519940A1; ES2519940B1

Abstract

The invention relates to a catheter design characterised by having a variable number of openings (2) in the different drainage rings (3), such that the uniformity of the flow of the fluid through the catheter (1) is facilitated, while the possibility of the openings (2) being obstructed is minimised, and the flow can be redistributed should any of the openings (2) become obstructed, thereby lengthening the useful life of the device. The invention also relates to two possible opening (2) distribution configurations based on described patterns for the distribution of openings (2) in rings (3), differing in terms of the distance between rings (3), the number of openings (2) in each of the rings (3), and the rotation of same.

Description

CATHETER FOR TREATMENT OF HYDROCEPHALIA

D E S C R I P C I O N OBJECT OF THE INVENTION

The present invention consists of a catheter of novel design conceived for the treatment of hydrocephalus, where traditionally this type of elements consists of a tubular shaped device arranged so that one of the ends is inserted into one of the ventricular cavities of the brain, of so that through the holes at that end it is possible to evacuate the accumulated cerebrospinal fluid, or to divert it to another part of the body where it is naturally absorbed. This end of the catheter is closed by its base (the "tip" of the catheter) to enable its insertion into the ventricle, and has holes arranged in its lateral wall in rings transverse to the axis of the catheter, called drainage rings or, simply, rings

More specifically, this device is characterized by having a variable number of holes in the drain rings, so that the uniformity of the passage of fluid through the catheter is favored, while minimizing the possibility of hole obstruction and redistribution of the flow is possible in the event that any of said holes become clogged, thus extending the life of the device. SCOPE

The present invention will have application within the medical components industry, more specifically within the field of devices intended for the derivation or evacuation of body fluids from a patient. BACKGROUND

Hydrocephalus (a term that derives from the Greek words "hydro" meaning water and "head" meaning head) is a disorder whose main characteristic is the excessive accumulation of fluid in the brain, resulting in an abnormal dilation of the spaces in the brain called ventricles, causing potentially damaging pressure on the tissues of the brain. Generally the increase in fluid in the ventricles is caused by the obstruction of the ducts located below the cerebellum. The usual treatment involves the drainage of excess fluid through a cannula or catheter inserted into one of the ventricular cavities of the brain. Said catheter disposes at the end inserted in the ventricle of several orifices through which the liquid penetrates for its extraction, while the opposite end is connected to a valve that regulates the pressure of exit of the liquid and transfers it well to a second catheter that directs the liquid to another part of the body where it can be absorbed or extracted outside, to a drainage bag. Currently there are various types of catheters to perform the said drainage.

The most common designs have 6 or 8 drain rings, each of these rings having a constant number of holes, usually 2 (opposite to the axis of the catheter) or 4 (opposite two to two). In most cases, the separation between the drain rings is identical, although there are also designs in which the distances between them vary.

Studies have been published (J. Neurosurg. 99 (2003), 426-431 J. Lin et al.) Where after numerically and experimentally analyzing these catheters, it was found that more than 80% of the cerebrospinal fluid mass flows through the two drain rings closest to the valve ("proximal rings"). The numerical study was based on a two-dimensional model, and based on this it is shown that by gradually varying the diameter of the holes (smaller in the proximal rings), the flow is uniformized, that is, the flow through the different rings Be similar. Following this first study, the type of catheter called Rivulet emerged, which was patented based on the results of that study. An advantage of the Rivulet design is that the suspended elements within the ventricle (macromolecules and tissues) can hardly be introduced through the proximal holes, minimizing the risk of clogging the inner duct of the downstream catheter and, therefore, rendering it useless by full. But that is also its weak point, because according to CA Harris and JP McAllister II (Childs Nerv. Syst. 27 (2011) 1221-1232), the adhesion of the suspended elements to the catheter generally increases as the hole diameter decreases , which favors the obstruction of the proximal holes in the Rivulet design.

Therefore, the appearance of a catheter design that makes it possible to standardize the flow through the drain rings but that, at the same time, minimizes the risk of clogging the holes, so as to extend the life of the device.

The catheter proposed herein achieves the same objective as the Rivulet catheter, namely to homogenize the distribution of the flow rates per ring, but without necessarily varying the diameters of the holes. In fact, the new design achieves this objective thanks to the variation in the number of holes in the drain rings, said number being greater in the distal rings (the farthest from the valve) and smaller in the proximal rings, optionally also combined with the variation of the size of the holes. This hole configuration also provides important advantages such as maintaining the uniformity of the flow when the drain rings are rotated independently, when holes are clogged randomly, or when the dimensions and / or geometry of the cavity of the cavity are varied. ventricle. In the case that the size of the holes is varied, this design prevents the holes from having to be excessively small and that there are large variations between their sizes.

It is known by the holder of the invention the existence of various documents concerning catheter models that have a certain relationship with the invention proposed in this application, such as: - Patent with publication number ES 2158548, Device for the treatment of hydrocephalus (Sinu Shunt, A / S, 18-09-1996) refers to a cerebrospinal fluid bypass system to derive cerebrospinal fluid from the cerebral ventricles to the sagittal sinus It consists of large strokes in a device composed of antechamber, flow regulator and check valve connected in series that allows to derive the cerebrospinal fluid from the ventricles to the sagittal sinus, bypassing the pathological obstruction that causes hydrocephalus and allowing said liquid to be diverted into place. of normal resorption, regulating the flow of the liquid so that it is within the normal limits and avoid complications due to hyper-drainage. This invention differs from that described in the present application in the fact of presenting a different objective, since its mission is not the drainage of the cerebrospinal fluid, but its derivation towards the area of natural absorption of this within the brain. Thus, the composition of the device is very complex compared to that described herein, in addition to the way in which the flow is regulated for the evacuation of the liquid, by means of valves and flow regulators differs completely from the way described herein. This invention therefore does not allow a simple intervention of insertion of the device and evacuation to the outside of the liquid since its high complexity forces its size to be relatively large, making it impossible to have a simple surgical intervention.

- Patent ES 2309089, Fluid bypass system for the treatment of hydrocephalus (CSF Dynamics A / S, 11-09-2001) describes a system composed of a cerebral ventricle catheter and a sinus catheter intended to bridge the obstacle which prevents the circulation of cerebrospinal fluid. The resistance to the flow of the system is set within different intervals, although it is not indicated how these values are achieved. No catheter configuration similar to that described in the present application is described.

- Patent ES 2126107, Variable pressure device with double valve for hydrocephalus (Phoenix Biomedical Corp., 03-05-1994) describes a device that solves the problems of single valve devices, which do not regulate the correct relationship between the volume of fluid drained and the intracranial pressure and can cause hyper drainage due to the siphon effect. Said device consists of a cylinder in which two valves are disposed inside, each with a differentiated function, at whose ends there are two input and output catheters of cerebrospinal fluid. This device differs in the object of the present invention, since it does not imply any improvement over any of the catheters that it incorporates, but is intended for the better control of the exit and entry of the liquid through said elements. - EP 0066685, Ion beam Sputter-etched ventricular catheter for hydrocephalus shunt (National Aeronautics and space administration, NASA, 01-04-1982) describes a catheter composed of a plurality of microtubes that conduct the cerebrospinal fluid, where each microtubes have of a plurality of holes as well as a larger inlet at the end. It differs from the invention which is recommended in the present application in the fact that it has a highly complex configuration in comparison, requiring for its manufacture a novel process in which bombardment of ion beams on polymer microtubes is used. The invention of the present application is capable of offering similar benefits through a simple and easily manufactured configuration.

- US 4432853, Method of making an ion beam sputter-etched ventricular catheter for hydrocephalus shunt (Bruce A. Banks, 24-11-1982) describes an improved method of manufacturing a microtube composite catheter as in the previous paragraph, by which also presents great differences with respect to the invention of the present application.

- Patent FR 2539298, Device for the treatment of hydrochloride avec catheter perfectionné (Université Rene Descartes, 14-01-1983) refers to a catheter in which at a predetermined distance its free end is arranged a collar that allows its positioning at the level of the dura, where next to said collar there is a plurality of holes that communicate with the subarachnoid spaces. Said holes are preferably axially elongated. and its rounded edges. This catheter, however, has the usual cerebrospinal fluid entry holes in this type of elements, so that it does not solve in any case the problems that the device of the present application solves.

- Document ES 2309462, Bypass system for hydrocephalus with endoscopic placement elements (Codman & Shurtleff, Inc., 03-26-2004) describes a system to derive the cerebrospinal fluid which has, among other elements, a catheter with one end for liquid collection and another end that is connected to a liquid extraction and bypass device. The liquid inlet catheter has holes with the usual configuration in this type of elements, so as in the invention of the previous paragraph, the problems indicated above are not solved.

Therefore, within the state of the art known to the holders of the present specification, it can be pointed out that no catheter design is known that has similar characteristics to those presented by the model that is recommended, therefore the novelty is evident of the present invention and for which the protection that is offered for these types of inventions is requested.

DETAILED DESCRIPTION OF THE INVENTION.

The catheter design that is recommended herein consists of a catheter similar to any of the traditional ones, configured as a thin and flexible hollow tube having at its closed end a series of holes distributed in various drain rings, where the number of holes in each of said rings is not the same in all of them. This general concept has been tested by numerous three-dimensional numerical simulations that allow you to easily compare current catheters with respect to new geometric configurations. These models reproduce in great detail the geometry of the catheters and allow to calculate a whole series of Descriptive parameters of the fluid (speed, pressure, shear stress, flow rate, etc.). As a result of these numerical analyzes, the properties of the designs based on variable hole distributions have been verified. The orifice distribution that characterizes the present invention has the following general characteristics:

- It consists of conical holes (that is, its walls are truncated conical surfaces), distributed in a series of drainage rings along a length less than 30 mm measured from the tip of the catheter. For reasons of mechanical strength, the number of holes per ring must not exceed 6.

- The distance between rings and the inner and outer diameters of the conical holes may vary depending on the desired flow distribution. For reasons of mechanical strength, the distance between rings must not be less than 0.5 mm. In order to increase the distance between different ring holes, it is recommended that adjacent rings be rotated relative to each other (which does not vary the flow distribution per ring). The number of holes in each ring will vary progressively, being greater in the distal rings (the farthest from the valve) and smaller in the proximal rings. In this way it is possible to standardize the flow through all the drain rings, as well as minimize the impact of possible obstructions in any of the holes.

The following are the guidelines to follow for the configuration of the distribution of holes in the rings:

Provision 1:

- The distance between adjacent drain rings may be the same in all rings, or vary between each one. - The angle between two holes of the same ring is defined from the first distal ring (the one closest to the tip of the catheter and with the greatest number of holes), so that it is calculated by dividing the 360 ° of the cross-section of the catheter Enter the number of holes.

- The next ring, in case of having the same number of holes, will have the same angular distance between them as in the previous ring, although (half of the angle between holes will be rotated with respect to the previous ring. Although this angular rotation does not affects the distribution of the flow, presents advantages from the point of view of the mechanical resistance of the catheter.

- In the event that a ring is reduced the number of holes with respect to the previous one, the same arrangement of holes of the previous ring would be maintained, with the rotation indicated since it is a new ring, and then the holes would be suppressed until reaching to the desired number and maintaining symmetry with respect to the axes of the cross-section of the catheter, so that the angle between holes would not necessarily be uniform (it would be in case of reducing the number of holes to 2).

Provision 2:

- The distance between adjacent drain rings may be the same in all rings, or vary between each one.

- The angle between two holes of the same ring is defined from the first distal ring (the one closest to the tip of the catheter and with the greatest number of holes), so that it is calculated by dividing the 360 ° of the cross-section of the catheter Enter the number of holes.

- The next ring, if it has the same number of holes, will have the same distribution.

- In case of reducing the number of holes in a ring with respect to the previous one, the same distribution will be maintained, subsequently removing the holes and maintaining symmetry at least with respect to one of the axes of symmetry of the catheter cross section.

In summary, then, provisions 1 and 2 differ by the existence (provision 1) or not (provision 2) of rotations between adjacent rings. As stated above, these rotations are advisable for reasons of mechanical resistance in designs with very close rings.

BRIEF DESCRIPTION OF THE FIGURES

To complement the description that is being made, and in order to facilitate a better understanding of the features of the invention, accompanying reports are attached hereto as part of the same, illustrative and non-limiting drawings, which are then given We proceed to describe:

Fig. 1.- A first configuration of the catheter is represented according to the orifice distribution patterns called "arrangement 1" with constant distance between rings, presenting a perspective view and a longitudinal section that is associated with a series of cross sections. corresponding to each drain ring, where the hole distribution can be easily observed.

Fig. 2.- A second configuration of the catheter is represented according to the orifice distribution patterns called "arrangement 1" with variable distances between rings, presenting a perspective view and a longitudinal section that is associated with a series of cross sections. corresponding to each drain ring, where the hole distribution can be easily observed. DESCRIPTION OF EXAMPLES OF EMBODIMENT

The present invention is illustrated by the following examples, not intended with its representation to limit its scope in any case, either partially or totally:

Example 1. A catheter formed by a hollow tube (1) of 2.5 mm outer diameter and 1.5 mm inner diameter is provided, which will have a total of 18 holes (2) and 4 drain rings (3) . The characteristics of each of the drain rings (3) are described below by a table, where they are designated from 1 to 4, with 1 being the ring closest to the tip (or closed end) of the catheter (4 ):

The distribution of holes (2) in the ring 1 will be such that a separation of 60 ° between each of them is arranged, while in the ring 2 they will be arranged with the same angular separation but rotated 30 ° with respect to the ring scheme 1. In the ring 3, the same distribution of the ring 1 is presented (that is, the configuration of the ring 2 by applying the 30 ° rotation again), removing two of the holes (2) so that the resulting arrangement presents symmetry with with respect to both axes of symmetry of the cross section of the tube (1). Finally, in ring 4 the same configuration of ring 3 will be presented by applying the 30 ° rotation and removing two holes (2) so that symmetry is preserved. Example 2. A catheter formed by a hollow tube (1) of 2.5 mm outer diameter and 1.5 mm inner diameter is provided, which will have a total of 24 holes (2) and 6 drain rings (3) , 1 being the ring (3) closest to the tip (or closed end) of the catheter (4). The main feature of this design is that the rings are grouped two by two, forming strips (5). Thus, rings 1 and 2 are grouped in a first strip (5), called distal, 1 mm from each other. Rings 3 and 4 are grouped in an intermediate strip (5), 1 mm from each other. Finally, rings 5 and 6 are grouped in a third strip (5), called proximal, also 1 mm from each other. The two rings of the distal fringe (5) each have 6 holes, decreasing this number to 4 in the intermediate fringe (5), and 2 in the proximal fringe (5). The characteristics of each of the drain rings (3) are described below in a table.

The holes (2) in rings 1 and 2 have an angular separation of 60 ° between them and the rotation between the first ring (3) and the second is 30 °. The holes (2) of rings 3 and 4 have an angular separation of 90 ° between them and the rotation between rings is 45 °. The holes (2) of rings 5 and 6 have an angular separation of 180 ° between them and the rotation between rings is 90 °.

Describing sufficiently the nature of the present invention, as well as the way of putting it into practice, it is not considered necessary to broaden its explanation so that any person skilled in the art understands its scope and the advantages derived therefrom, stating that, within its essentiality, it may be put into practice in other embodiments that differ in detail of that indicated by way of example, and which will also achieve the protection that is sought as long as it does not alter, change or modify its fundamental principle.

Claims

1. CATHETER FOR TREATMENT OF HYDROCEPHALIA, configured from a hollow tube (1) and closed by a tip (4), in which a series of holes (2) distributed in transverse rings (3) are laterally arranged, characterized because the number of holes (2) present in each of the rings (3) varies from one ring to another, where the number of holes in each ring will vary progressively, being greater in the distal rings (3) (the most near the tip (4)) and smaller in the proximal rings (3) (the furthest from the tip).

2. CATHETER FOR TREATMENT OF HYDROCEPHALIA, according to claim 1, characterized in that the distribution of holes (2) follows the following guidelines:

- The distance between adjacent drain rings (3) may be the same in all rings, or vary between each one.

- The angle between two holes (2) of the same ring (3) is defined from the first distal ring (3) (closest to the tip of the catheter (4) and with greater number of holes (2)), so that it is calculated by dividing the 360 ° of the cross section of the catheter by the number of holes (2).

- The next ring (3), in case of having the same number of holes (2), will have the same angular distance between them as in the previous ring (3), although half the angle between holes (2) will be rotated with respect to the previous ring (3).

- In the event that a ring (3) is reduced the number of holes with respect to the previous one, the same hole arrangement of the previous ring (3) is maintained, with the rotation indicated for a new ring (3), and then they suppress the holes (2) until reaching the desired number and maintaining symmetry with respect to the symmetry axes of the catheter cross section.

3. CATHETER FOR TREATMENT OF HYDROCEPHALIA, according to claim 1, characterized in that the distribution of holes (2) follows the following guidelines:

The angle between two holes of the same ring (3) is defined from the first distal ring (3) (closest to the tip of the catheter (4) and with the greatest number of holes (2)), so that calculated by dividing the 360 ° of the catheter cross section by the number of holes.

The next ring (3), if it has the same number of holes, will have the same distribution.

If the number of holes in a ring (3) is reduced with respect to the previous one, the same distribution will be maintained, subsequently suppressing the holes (2) and maintaining the symmetry at least with respect to one of the axes of symmetry of the catheter cross section.

4. CATHETER FOR TREATMENT OF HYDROCEPHAL, according to claims 1 and 2, characterized in that it has 18 holes distributed in four rings, with the following characteristics:

Ring 1 Ring 2 Ring 3 Ring 4

No. 6 holes 6 4 2

Distance to

4.5 9.0 13.5 18.0 tip (4) (mm)

Int / ext radio

0.25 / 0.20 / 0.25 / holes (2) 0.20 / 0.50

0.50 0.50 0.50 (mm) CATHETER FOR TREATMENT OF HYDROCEPHALIA, according to claims 1 and 3, characterized in that it has 24 holes distributed in three strips (5) of two rings (3) each, with the following characteristics:

Strip Strip

Distal stripe

proximal intermediate

No. 2x6 2x4 2x2 holes

Distance

rings at 4.5 / 6.5 12.0 / 14.0 19.5 / 21.5 tip (4) (mm)

Int./ext radio

of holes (2) 0.25 / 0.50 0.20 / 0.50 0.25 / 0.50 (mm)