Bio-medical pressure control device

Abstract

A cerebrospinal fluid anti-siphoning device for insertion into the human body to provide regulation of fluid being transported from the lateral ventricles to another part of the body. The device includes a fluid housing member through which the cerebrospinal fluid passes. The fluid housing member is adapted to contain a pair of check valves which control fluid flow through the housing member and prevent back flow from a downstream area to an upstream area. A central chamber within the fluid housing member encloses a fluid control mechanism which provides for termination of fluid flow when the downstream pressure becomes too low with respect to the upstream pressure. The fluid control mechanism includes a diaphragm which is displaced from a fluid conduit when flow is passing through the fluid housing member and is positioned contiguous to the conduit opening when the downstream pressure is too low, thereby effectively terminating the flow of the cerebrospinal fluid through the fluid housing member. The device includes a mechanism for manually actuating the flow through the outlet area of the housing member even when the antisiphoning device has been implanted within the human body.

Description

INCORPORATION BY REFERENCE

This application incorporates by reference U.S. Pat. No. 3,566,875 issued Mar. 2, 1971.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to devices for draining cerebrospinal fluid during treatment of hydrocephalus.

2. Prior Art

Devices for draining cerebrospinal fluid are known in the art. However, in some prior devices one way check valves are incorporated to promote drainage of the cerebrospinal fluid. Such valves fluidly communicate with the brain area and other parts of the body to which the fluid is being drained. However, a rapid decrease in the pressure of the parts of the body to which the fluid is being drained may cause too much fluid to be transported from the brain in a manner which is too rapid. Such a condition may have diliterious results and possibly cause death of the patient within which the prior devices have been implanted. Such prior devices do not include a mechanism whereby the fluid flow may be terminated when the downstream pressure or pressure of the body to which the fluid is being drained becomes too low with respect to the upstream fluid pressure. Such prior devices do not provide automatic control of the fluid being drained dependent upon the pressure differential experienced by the devices.

SUMMARY OF THE INVENTION

A cerebrospinal fluid anti-siphoning device which comprises a fluid housing mechanism having a central chamber. An inlet mechanism is in fluid communication with the central chamber for insertion of the fluid into the chamber. The device includes an outlet mechanism in fluid communication with the central chamber for transport of the fluid from the chamber. Further, the device includes a mechanism for controlling the flow of the cerebrospinal fluid through the central chamber of the fluid housing mechanism responsive to a predetermined pressure differential between the inlet mechanism and the outlet mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the cerebrospinal fluid anti-siphoning device implanted within a human body;

FIG. 2 is a blow out view of the anti-siphoning device;

FIG. 3 is a top view of the anti-siphoning device;

FIG. 4 is a sectional view of the anti-siphoning device taken along the section lines 4--4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1, 2, and 3, there is shown cerebrospinal fluid anti-siphoning device 11 for insertion into the human body. Device 11 is provided to control passage of cerebrospinal fluid being transported from an upstream to a downstream area 13, 15 respectively. Device 11 forms a mechanism whereby the fluid pressure differential between upstream and downstream conditions may be effectively monitored, such that when the fluid pressure differential surpasses a predetermined value, the flow of fluid passing through device 11 is terminated. In general, the pressure of the fluid entering inlet tube 17 is higher than the pressure of the fluid egressing from device 11 through outlet tube 19. This pressure differential provides for a flow of the fluid from upstream 13 to downstream 15 through device 11. However, it should be understood that where the pressure differential exceeds a predetermined value, excessive drainage of the fluid from the brain area may be encountered. It is the purpose of device 11, as will be described in the following paragraphs, to terminate the flow of the fluid when the pressure differential exceeds the prescribed value.

It is to be understood that device 11 includes upstream check valve 22 and downstream check valve 24 inserted into upstream and downstream inlet and outlet areas 21 and 23 respectively. Check valves 22 and 24 are similar in construction to those valves shown and described in U.S. Pat. No. 3,566,875 which is herein incorporated by reference. In general, each of check valves 22, 24 shown and described in the referenced patent includes an inner elastic tubular member within an outer tube. Formed in the region of the downstream end of each inner tubular member is an axially extending slit which forms a valve opening. The valves are designed to automatically open when the pressure within each inner tubular member exceeds the pressure at the exterior thereof by a given slight amount. The referenced slit automatically opens due to this pressure differential while automatically closing when the internal pressure is less than the external pressure of each tubular member by less than that pressure required to open the slit.

In general, device 11 is positionally located within the human body adjacent skin area 25. Device 11 is further positioned in the clavicle area of the human body with inlet tube 17 passing to the lateral ventricals within the skull for drainage of the cerebrospinal fluid therefrom. Outlet tube 19 of device 11 passes to another portion of the body such as the peritoneal cavity to permit drainage of the fluid thereto.

Cerebrospinal fluid anti-siphoning device 11 includes fluid housing member 27 having central chamber or cavity 29 through which the fluid flows. In a top cross-section, housing member 27 is similar in geometrical contour to a diamond or rhomboid, however, such is not critical to the inventive concept as herein described. Housing member 27 may be formed of medical grade silicone rubber or some like material adapted for insertion into the human body with the only restriction being that such material does not degrade within the environment where it is positioned, as well as contaminate the body or fluid passing therethrough. Inlet area 21 of fluid housing member 27 is connected to inlet tube 17 and is in fluid communication with central chamber or cavity 29 for insertion of the fluid passing from the brain area through inlet tube 17 into chamber 29. In similar fashion, outlet area 23 is connected to outlet tube 19 and is in fluid communication with chamber or cavity 29 for transport of the fluid from chamber 29 through outlet tube 19 to the peritoneal cavity or other area of the body so designated to receive the excessive cerebrospinal fluid being transported through device 11. Inlet and outlet tubes 17, 19 may be constructed of polyethylene or some like material which will remain substantially inert with respect to the body environment through which they pass. Located within fluid housing member 27 and further, within cavity 29 there is fluid control mechanism 31 for controlling or regulating the flow of the cerebrospinal fluid through central chamber 29 responsive to a predetermined pressure differential between inlet or upstream condition 13 and outlet or downstream condition 15.

Fluid control mechanism 31 describes a valve mechanism within chamber 29 for terminating the flow of fluid from inlet area 21 to outlet area 23 when the pressure differential between the inlet and outlet areas 21, 23 exceeds a predetermined value. This valve mechanism includes fluid egress conduit 33 within fluid housing member 27 which is in fluid communication with outlet area 23 for passage of fluid into downstream valve 24. Further, the aforementioned valve mechanism includes flexible diaphragm mechanism 35 which forms a lower surface of central chamber 29 and is positionally located adjacent to fluid conduit 33 as is shown in the figures.

As will be described in the following paragraphs, flexible diaphragm 35 may be displaced away from egress conduit 33 when fluid is passing through device 11 which would result when the pressure differential between the inlet area 21 and outlet area 23 is less than a predetermined value. Further, when the pressure differential exceeds the predetermined amount diaphragm 35 is opposingly drawn into contiguous relation with conduit opening 37 thereby blocking the passage of fluid through conduit 33 into outlet area 23 and downstream valve 24 for displacement through outlet tube 19. In general, fluid conduit 33 is L-shaped in geometrical contour and has a first end 39 which is in fluid communication with outlet area 23 and a second end 41 which has conduit opening 37 for passage of the fluid. The displacement distance between diaphragm 35 and second end 41 of conduit 33 provides a continuous fluid passage opening for transport of the fluid from inlet area 21 through fluid housing member 27 and finally to outlet area 23. As is seen in the figures, second end 41 includes lip section 43 which provides the area of contact when flexible diaphragm 35 is drawn into a blocking mode of operation. Lip section 43, as is seen, provides a slightly flared section and is upturned slightly with respect to the remaining wall section of fluid conduit 33. Diaphragm 35 is mounted within fluid housing 27 either through bonded securement or through insertion in a recess therein provided. In this manner, diaphragm 35 may be movably displaced in an upward or downward direction dependent upon the pressure condition it experiences.

In operation, fluid control mechanism 31 may be seen to function in a plurality of states. Assuming that all the pressures in upstream and downstream areas 13, 15 are equal, it is to be understood that diaphragm 35 will lie substantially contiguous with second end 41 of conduit 33. When device 11 is inserted into the human body or otherwise when the pressure of inlet area 21 exceeds outlet area 23 within a predetermined range, flow is initiated through inlet tube 17 into cavity 29. This causes a pressure to be exerted downwardly on diaphragm 35 thus displacing diaphragm 35 away from conduit opening 37. Since the downstream 15 pressure is less then the upstream 13 pressure, fluid flows into conduit opening 37 and through conduit 33 to outlet area 23. However, where the downstream 15 pressure drops to a low level with respect to upstream 13 pressure, diaphragm 35 is pulled upwardly into contiguous contact with section 43 of second end 41 of conduit 33. Once diaphragm 35 is contiguously in relation with second end 41, flow of fluid through egress conduit 33 is effectively blocked and flow is terminated from inlet tube 17 to outlet tube 19. As was the case in the construction of fluid housing member 27, both flexible diaphragm 35 and fluid egress conduit 33 are similarly constructed of a medical grade silicone rubber or some like material.

As is shown in the figures, fluid housing member 27 includes flexible dome 43 extending above upper surface 45. Dome 43 is mated to housing 27 through insert into a recess, or affixedly secured by bonding or some combination thereof. Dome 43 forms an upper surface of chamber 29 and is hat-shaped in geometrical contour. Dome 43 is further positionally located adjacent outer skin surface 25 when device 11 is implanted within the body. Dome 43 is flexibly constructed of a medical grade silicone rubber or some like material and is adapted to be compressed into chamber 29 for increasing the fluid pressure within chamber 29 thereby allowing manual displacement of diaphragm 35 away from conduit opening 37 to permit transport of the fluid through outlet area 23. In order to give structural support to housing member 27 surface 47 may by interspersed between the area under dome 43 and fluid control mechanism 31. However, in this form, fluid communication is maintained between dome 43 and control mechanism 31 through openings 48 passing through surface 47 and thus, allowing fluid or air to pass therethrough when dome 43 is depressed. Thus, it is seen that where diaphragm 35 is in contiguous relation with conduit opening 37 of egress conduit 33, no flow passes into outlet area 23. This condition may occur through a number of ways, such as the pressure differential between outlet and inlet areas 21, 23 being too great or through possible debris found in the cerebrospinal fluid. Where such is the case and it is desired to flush the system or otherwise to initiate the flow between upstream 13 and downstream 15, dome 43 may be depressed thereby increasing the pressure against flexible diaphragm 35 and displacing it away from fluid egress conduit opening 37. In this case, fluid then begins to flow through conduit 33 through manual actuation of the depression of dome 43.

Device 11 includes diaphragm restraint mechanism 49 secured to fluid housing member 27 below diaphragm 35. Restraint member 49 is displaced from diaphragm 35 through a predetermined amount to permit a flexible movement of diaphragm 35 upwardly or downwardly. Restraint member 49 is secured to housing 27 through fixed securement such as bonding or insertion into a recess, or a combination of such means. In general, restraint member 49 may be a plate element having openings 51 formed therethrough. Plate 49 is constructed or formed of nylon or some like material. As has been described, restraint member 49 may be a plate member having openings 51 or may be formed in a grid type shape. The purpose of plate 49 is to prevent diaphragm 35 from being blown out of housing member 27 when dome 43 is compressed. When dome 43 is depressed a relatively high pressure impinges upon diaphragm 35 and forces it in downward displacement wherein it is restrained through contact or interaction with plate 49. Openings 51 in plate 49 provide for the displacement of any fluid through those openings when diaphragm 35 is downwardly displaced. This insures that diaphragm 35 does not remain rigidly displaced with respect to plate 49 through the damping of the fluid or other material therebetween, and permits free movement of diaphragm 35 responsive to the fluid pressure.

Normal fluid pressure in the brain area is generally equal to or greater than 200 mm. of water. However, in the case of hydrocephallus, the fluid pressure in the brain may exceed normal values. For this reason upstream and downstream valves 22 and 24 provide a means whereby fluid may be drained from the brain. However, where the pressure in the outlet area 23 becomes to low, too much fluid may possibly be drained off and the drainage may be too rapid. Thus device 11, within which valves 22 and 24 are inserted, may be constructed to terminate the flow of cerebrospinal fluid when the downstream pressure becomes too low.

Through proper construction and positional relationships of diaphragm 35 with respect to conduit opening 37, device 11 can be made to terminate fluid flow throughout a wide range of downstream pressures. Generally, device 11 is constructed to terminate flow when the downstream pressure drops to 20-90 mm. of water. As an example, diaphragm 35 has a thickness approximately within the range of 0.005-0.01 inches in thickness and is so constructed as to be displaced from second end 41 approximately 0.004-0.020 inches when fluid is flowing therethrough. Further, as an example, plate 49 may have an approximate thickness of 0.050 inches and include an approximate diameter of 0.50 inches. It is to be understood that the foregoing examples of dimension and positional relations are used for illustration only and that control of fluid flow termination may be regulated over a wide range of pressures by changing construction geometries.

Claims

What is claimed is:

1. A cerbrospinal fluid anti-syphoning device comprising:

a. fluid housing means having a central chamber, said fluid housing means including a flexible dome forming an upper surface of said central chamber, said flexible dome adapted to be depressable into said central chamber for increasing fluid pressure therein;

b. inlet means in fluid communication with said central chamber for insertion of said fluid into said chamber;

c. outlet means in fluid communication with said central chamber for transport of said fluid from said chamber;

d. fluid egress conduit means extending internal said central chamber and in fluid communication with said outlet means;

e. flexible diaphragm means forming a lower continuous surface of said central chamber, said diaphragm means being positionally located adjacent said fluid egress conduit means, said diaphragm means adapted to block flow of said fluid through said fluid egress conduit means when a fluid pressure differential between said inlet and outlet means is less than a predetermined value; and,

f. diaphragm restraint means secured to said housing and positioned below said diaphragm means for preventing said flexible diaphragm means from being externally displaced from said housing means when said flexible dome is depressed, said diaphragm restraint means being a plate member having at least one opening passing therethrough.

2. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said flexible diaphragm means is displaced from said fluid conduit means when said pressure differential between said inlet means and said outlet means is less than a predetermined value and said fluid is being transported through said central chamber.

3. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said flexible diaphragm means is contiguous to a fluid passage opening of said fluid conduit means when said pressure differential between said inlet means and said outlet means exceeds said predetermined valve thereby blocking flow of said fluid to said outlet means.

4. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said fluid egress conduit means includes an L-shaped conduit having a first end connected to and in fluid communication with said outlet means and a second end adjacent said diaphragm means forming a fluid passage opening for transport of said fluid within said chamber to said outlet means.

5. The cerebrospinal fluid anti-siphoning device as recited in claim 4 where said second end of said conduit provides a contact area with said diaphragm means greater than the flow area of said fluid through said conduit.

6. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said valve means is constructed of silicone.

7. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said flexible dome is adapted to be compressed into said chamber for increasing the fluid pressure within said chamber thereby displacing said fluid through said outlet means.

8. The cerebrospinal fluid anti-siphoning device as recited in claim 7 where said flexible dome is constructed of silicone rubber.

9. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said diaphragm restraint means includes a plate member displaced from said diaphragm means, said plate member being fixedly secured to said fluid housing means.

10. The cerebrospinal fluid anti-siphoning device as recited in claim 9 where said plate member includes a plurality of openings passing therethrough.

11. The cerebrospinal fluid anti-siphoning device as recited in claim 10 where said plate member is constructed of nylon.

12. The cerebrospinal fluid anti-siphoning device as recited in claim 1 where said diaphragm restraint means includes a grid member mounted to said fluid housing means.

13. The cerebrospinal fluid anti-siphoning device as recited in claim 12 where said grid member is constructed of nylon.

14. The cerebrospinal anti-siphoning device as recited in claim 1 including inlet valve means inserted within said inlet means of said fluid housing means for transporting said fluid into said central chamber when said inlet fluid pressure is in excess of a predetermined value.