Apparatus for shunting cerebrospinal fluids

Abstract

A cerebrospinal fluid shunt device comprises: a tubular inlet (4) comprising an inlet end (41) configured for insertion into a cerebrospinal fluid containing space of the individual, the inlet end having an inlet opening (411) for receiving cerebrospinal fluid, a tubular outlet (2) comprising an outlet end (21) configured for insertion into a venous system cavity of the individual, the outlet end comprising an outlet opening (211), wherein the inlet opening is fluidly connected with the outlet opening to allow cerebrospinal fluid to flow from the inlet opening to the outlet opening, a fixator (213) attached to the outlet end and configured to secure a location of the outlet end in the venous system cavity by exerting a radial outward force onto a wall of the venous system cavity at a deployment location of the outlet end in the venous system cavity.

Description

[0001]Apparatus and Methods for Shunting Cerebrospinal Fluids Technical Field The present disclosure relates to apparatus and methods for shunting cerebrospinal fluids from a cerebrospinal fluid containing space of an individual to facilitate drainage of cerebrospinal fluids and to relieve, e.g., an elevated intracranial pressure in the individual. Various methods disclosed herein use a cerebrospinal fluid shunt device comprising a tubular outlet having an outlet end with an outlet opening. Background The complication rates associated with shunting cerebrospinal fluid (CSF) for the treatment of hydrocephalus remain unacceptably high despite many attempted technical improvements since shunts were first invented in the 1950s. Modifications have been made in recent decades with features intended to compensate for the changes between intracranial pressure (ICP) and receiving drainage sites, such as adjustable valves or anti-gravitational features, but even recent reviews fail to register the impact of these enhancements on shunt failure rates. Many current shunting technologies do not address a fundamental issue: The choice of drainage sites (most commonly the peritoneum and atrium) is “unphysiological” and fluctuating and / or arbitrary pressure differences between these sites and ICP will therefore always be a challenge to manage mechanically. Shunting implies intervention in a complex, multidimensional system involving physiological variables such as CSF production, CSF outflow, pressure, cerebral compliance, cardiac output, body position, and physical activity. When shunting CSF to the intraperitoneal cavity, for example, which is standard practice for most hydrocephalus shunt operations, the flow in the shunt is entirely dependent on the pressure difference between the intracranial and intraabdominal compartments. The intraabdominal pressure fluctuates greatly in the short term as well as the long term and depends on posture and physical activity such as breathing, walking, lifting, etc.,1as well as obesity, among other factors.2When taking all these factors and their delicate balance into consideration, the diversion of CSF to the peritoneal cavity or right atrium of the heart by means of a drain with a predetermined flow or pressure restriction is highly artificial; the known risks of complications and side effects are therefore considered somewhat inevitable. However, because this intervention is the standard of care for managing the condition, the inherent complications are reluctantly tolerated as an unfortunate necessity. Manufacturers have attempted to overcome the limitations of shunts with the introduction of anti-siphoning devices (more accurately, devices with valves to compensate for siphoning), programmable shunts (adjustable valves), or self-adjusting CSF flow-regulating shunt devices. This has not, however, resulted in significant reductions of re-operations or in extended revision-free periods after shunt implantation.3In their Cochrane review, Garegnani et al.4concluded: “Standard shunt valves for hydrocephalus compared to anti-siphon or self-adjusting CSF flow-regulating valves may cause little to no difference on the main outcomes.” In fact, the frequency of reoperations within the first 6 months following shunt implantation is generally reported to be 25% – 30%.4–6A recent report cites a particularly poor outcome of 32.6% shunt failures 30 days after insertion in patients older than 50 years in the US.5The 5-year survival rate for any type of CSF shunt investigated is only approximately 50%, inevitably resulting in many repeated surgeries.6There is a lack of accurate comprehensive data to be found on shunt revision surgeries across different geographical regions, but the annual figures available from the Danish national health database that captures all procedures in the country show a 58% revision and removal rate of hydrocephalus shunts (2021).7 Unwaveringly high failure and complication rates and the absence of breakthrough devices are compelling reasons for exploring new apparatus and methods for relieving elevated cerebrospinal pressure in an individual by diverting cerebrospinal fluids from the ventricles to a sinus system cavity or another suitable drainage site. In subjects suffering from elevated intracranial pressures, such as, e.g., hydrocephalus, drainage of cerebrospinal fluids from the ventricles is impaired, and it is necessary to provide a shunt device to ensure sufficient drainage of cerebrospinal fluids from the ventricles. When inserting a shunt device into the ventricles to drain cerebrospinal fluids to relieve an elevated intracranial pressure, the shunt device should preferably restore the physiological drainage of cerebrospinal fluids from the ventricles. Excess drainage of cerebrospinal fluids from the ventricles should be avoided. In view of the above-cited technical challenges there is a need for improved shunt devices and methods aimed at draining excess cerebrospinal fluids from the ventricles without the risk of over-drainage or under-drainage, or for shunt devices or methods that at least can serve as alternatives to existing solutions. Summary According to a first aspect, disclosed herein are embodiments of a cerebrospinal fluid shunt device for shunting cerebrospinal fluid from a cerebrospinal fluid containing space and into a venous system cavity of an individual, wherein the cerebrospinal fluid shunt device comprises: - a tubular inlet comprising an inlet end configured for insertion into a cerebrospinal fluid containing space of the individual, the inlet end having an inlet opening for receiving cerebrospinal fluid, - a tubular outlet comprising an outlet end configured for insertion into a venous system cavity of the individual, the outlet end comprising an outlet opening, wherein the inlet opening is fluidly connected with the outlet opening to allow cerebrospinal fluid to flow from the inlet opening to the outlet opening, - a fixator attached to the outlet end and configured to secure a location of the outlet end in the venous system cavity by exerting a radial outward force onto a wall of the venous system cavity at a deployment location of the outlet end in the venous system cavity. The fixator is configured to be converted from a compacted state of the fixator into an expanded use state of the fixator to secure the outlet end at the deployment location, wherein the radial force is between about 0.1 Newton and 1.0 Newton in the expanded use state. The inventors have realized that the radial force from about 0.1 Newton to 1.0 Newton in the expanded use state is strong enough to secure the fixator and, hence, the outlet end at the deployment state and to prevent it from being unintentionally displaced. The radial force from about 0.1 Newton to 1.0 Newton in the expanded use state is also weak enough to reduce or even eliminate the risk that the fixator damages or otherwise impairs the wall of the venous system cavity, in particular the vein wall, or that the fixator damages or otherwise impairs structures, such as bone or nerves, in the proximity of the venous system cavity at the deployment location. According to a second aspect, the present disclosure provides a method of implanting a cerebrospinal fluid shunt and a method of shunting cerebrospinal fluid from a cerebrospinal fluid containing space of an individual to a foramen jugulare of the individual. In various embodiments of the method of implanting a cerebrospinal fluid shunt, the cerebrospinal fluid shunt comprises at least a tubular inlet and a tubular outlet. The method comprises positioning the cerebrospinal fluid shunt with at least part of an inlet end of the tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, and with at least part of an outlet end of the tubular outlet, the outlet end comprising an outlet opening, at a deployment location at, in particular in, a foramen jugulare of the individual, such that the inlet opening is fluidly connected with the outlet opening so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening. In various embodiments, the method of shunting cerebrospinal fluid from a cerebrospinal fluid containing space of an individual to a foramen jugulare of the individual comprises the steps of: i) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, ii) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the foramen jugulare of the individual, and iii) shunting cerebrospinal fluid from the cerebrospinal fluid containing space of the individual to the foramen jugulare of the individual. There is also provided a method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in a foramen jugulare of an individual. Various embodiments of said method comprise the steps of a) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, b) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the foramen jugulare of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening of the outlet end inserted into the foramen jugulare of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening. Embodiments of the methods disclosed herein are useful for treating individuals, including human beings, suffering from elevated intracranial pressure, such as hydrocephalus, including normal pressure hydrocephalus. The cerebrospinal fluid containing space can be a ventricle or a subarachnoid space. The ventricle may be a lateral ventricle. The shunt device may be the shunt device in accordance with the first aspect, or another suitable shunt device. When at least a part of the outlet end is positioned in the foramen jugulare, the outlet opening may be positioned inside the foramen jugulare or immediately superior or inferior the foramen jugulare. A shunt body may operably connect under practical circumstances the inlet end of the tubular inlet, the inlet end comprising an inlet opening inserted into the cerebrospinal fluid containing space of the individual, with the outlet end of a tubular outlet, the outlet end comprising an outlet opening and being inserted into the foramen jugulare of the individual. The shunt body may be connected at one end to the tubular inlet having an inlet end with an inlet opening configured for insertion into a ventricle of an individual, and connected at another end to the tubular outlet having an outlet end with an outlet opening configured for insertion into the foramen jugulare of the vena jugularis of the individual. When practicing the above-captioned methods, an outlet end of the tubular outlet, the outlet end comprising the outlet opening, may initially be inserted into vena jugularis and then guided through the vena jugularis and into the foramen jugulare. The outlet end of the tubular outlet is thus deployed inside the vena jugularis at a position where the vena jugularis passes through the foramen jugulare. Accordingly, some embodiments of the methods disclosed herein may comprise: - guiding the outlet end of the tubular outlet, the outlet end comprising the outlet opening, through the vena jugularis towards the foramen jugulare, and - locating the outlet end of the tubular outlet in a cavity of the foramen jugulare, such as, e.g., the jugular bulb or an upper portion of the vena jugularis. When located in the foramen jugulare, the outlet end of the tubular outlet, the outlet end comprising the outlet opening, is preferably secured by a fixator comprised by the tubular outlet. One way of securing the outlet end of the tubular outlet, the outlet end comprising the outlet opening, in the foramen jugulare is by converting a fixator attached to the outlet end of the tubular outlet from a compacted state into an expanded use state. When a fixator attached to the outlet end of the tubular outlet is changed from a compacted state to an expanded use state, the fixator exerts a force, in particular a radially outward force, on the walls of a foramen jugulare cavity, in particular on a cavity wall of the vena jugularis passing through the foramen jugular, and maintains the outlet end of the tubular outlet, the outlet end comprising the outlet opening, at a position in the foramen jugulare radially displaced from and without contacting endothelial tissue. The outlet end with the fixator attached to it may, in practical circumstances, be partly positioned inside the jugular foramen and partly extend superiorly and / or inferiorly out of the foramen jugulare. Brief description of the Drawings Embodiments of various aspects of the apparatus and methods for shunting of cerebrospinal fluid disclosed herein will be described in more detail below and with reference to the drawings, in which: FIGs.1A-B illustrate a shunt device for draining cerebrospinal fluids in an individual. FIG.2 schematically shows the outlet end of a tubular outlet of an example of a shunt device. FIGs.3A-B illustrate an example of a shunt body of an embodiment of a shunt device. FIG.4 illustrates the dural venous sinus system of a human patient. FIGs.5A-D illustrate a process for insertion of the outlet end of the tubular outlet into the foramen jugular of an individual. FIG.6 illustrates an example of a method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in the vena transversa of an individual. FIG.7 illustrates an example of a method of extracting an outlet end of a shunt device from a sinus cavity system of an individual. Detailed Disclosure Embodiments of various aspects of the shunting of cerebrospinal fluid will be described in more detail below. Alternative embodiments substantially identical or essentially similar to the below-disclosed embodiments will be within reach of a skilled person aiming to practice the below-disclosed methods of shunting cerebrospinal fluids in an individual and / or to provide the below-disclosed shunt device. Shunt devices for use in draining cerebrospinal fluids in an individual FIGs.1A-B illustrate a shunt device for draining cerebrospinal fluids in an individual. FIG.1A shows the shunt device implanted in a human patient 5, while FIG.1B shows an enlarged view of the outlet end of the shunt device positioned in the foramen jugulare. Generally, a shunt device for use in the methods disclosed herein and / or in other methods comprises a tubular inlet 4 comprising an inlet end 41 with an inlet opening 411 configured for insertion into a cerebrospinal fluid (CSF) containing space of an individual. The shunt device further comprises a tubular outlet 2 having an outlet end 21 for insertion via a penetration point 51 into the vena jugularis 52 and for being guided towards a deployment site in the foramen jugulare 53. FIG.2 illustrates an outlet end 21 of a tubular outlet 2 of a shunt device for draining cerebrospinal fluids in an individual, e.g. of the shunt device of FIGs.1A-B. The outlet end 21 has an outlet opening 211 and is configured for insertion in a sinus system cavity, such as vena jugularis, in particular in the foramen jugulare 53 or another suitable deployment position. Referring to FIG.2 and with continued reference to FIGs.1A-B, the above-mentioned tubular elements, i.e. the tubular inlet and the tubular outlet, comprise inner lumens that extend through the respective tubular elements. The inner lumen of the tubular inlet 4 and the inner lumen of the tubular outlet 2 are operably connected so that cerebrospinal fluids can be shunted or drained through the shunt device from the inlet opening 211 inserted into a cerebrospinal fluid containing space to the outlet opening inserted into a sinus system cavity, such as vena jugularis, in particular in the foramen jugulare (“jugular foramen”) and / or bulbus superior venae jugularis (“jugular bulb”) 54. The shunt device preferably comprises a fixator 213 for securing the outlet opening 211 of the shunt device when the outlet opening is inserted into a sinus system cavity and for avoiding contact of the outlet opening with the endothelial wall of the sinus system cavity, such as vena jugularis and / or jugular bulb, and / or bone sections, such as the jugular foramen. The fixator also serves to maintain the outlet end of the tubular outlet at a distance from endothelium tissue and bones, such as at a predetermined and / or essentially fixed distance from endothelium tissue and bones. In some embodiments, the shunt devices disclosed herein comprise a tubular inlet 4 having an inlet end 41 with an inlet opening 411 configured for insertion into a ventricle of an individual. The shunt devices of such embodiments may further comprise a shunt body 3, and a tubular outlet 2 having an outlet end 21 with an outlet opening 211, the outlet end being configured for insertion into the vena jugularis at the foramen jugulare, or at another suitable deployment location. The tubular inlet 4 may thus be a ventricular catheter. In various embodiments, the shunt devices disclosed herein comprise a flow restricting part positioned between the inlet opening and the outlet opening, and a one-way valve preventing back-flow of cerebrospinal fluids, i.e. preventing cerebrospinal fluids from flowing from the outlet opening to the inlet opening of the shunt device. In some embodiments, the shunt device may comprise a fixed or adjustable pressure- control and / or flow-control valve for regulating the amount of CSF being drained. A fixed valve may regulate the intracranial pressure based on a predetermined pressure and / or flow setting. An adjustable valve (sometimes also referred to as a programmable valve) may regulate the intracranial pressure based on a pressure and / or flow setting that can be adjusted by a physician using an external adjustment tool. An adjustable valve may be configured to adjust the opening pressure of the valve and / or to adjust the flow resistance of the adjustable valve. Alternatively, or additionally, the adjustable valve may be adjustable to a closed state, where the adjustable valve remains closed regardless of the pressure. The tubular outlet may also be referred to as a drainage catheter or a sinus catheter and the outlet end with the attached fixator may be referred to as a venous access port (VAP). The shunt body 3 may comprise a housing and one or two check valves. The housing may be a titanium housing. The housing may accommodate an antechamber. Each of the one or two check valves may be a ball-in-cone check valve, a duckbill valves, and / or an umbrella valve. In case of two check valves both check valves may be of the same type or of different types. The antechamber may be constructed with a silicone dome to enable compression (i.e., palpation) and penetration with a cannula. One of the ball-in-cone check valves may prevent backflow into the ventricles when the dome is compressed for the purposes of functional performance. The second ball-in-cone check valve may be spring-loaded. The spring may be configured to provide a predetermined opening pressure, e.g. of about 3 ± 1.5 cm H2O (water column), and the ball-in-cone prevents backflow from the outlet end of the shunt device. The inlet and the outlet of the housing of the shunt body may comprise two barb connectors, one for a ventricular catheter and one for the tubular outlet. The tubular outlet may comprise, or consist of, a flexible tubular member 22 (which will also be referred to as a catheter tube 22) and a resistance tube 212. A fixator 213 is attached at the outlet end of the flexible tubular member 22. The flexible tubular member 22 may be a silicone catheter tube, e.g. a sulphate impregnated silicone catheter tube. The silicone catheter tube is preferably long enough (e.g.60 cm long) to allow it to be cut to length during implantation. The silicone catheter tube 22 holds the resistance tube 212, which may be a PEEK (polyether ether ketone) nozzle. The resistance tube provides a stiff outflow at the catheter end which can be held securely and centered within the vein by the fixator. The fixator 213 may be an electropolished nitinol fixator which facilitates a secure fixation in the jugular foramen or at another suitable deployment location. The flow rate of CSF through the shunt device is governed by the stable differential pressure (DP) between the shunt inlet (in particular the ventricles of the brain) and the shunt outlet, and by the production rate of CSF (about 0,35 ml / min, and relatively constant), which is the same principle as in conventional physiological CSF drainage. However, in various embodiments disclosed herein, the shunt outlet is positioned in the jugular foramen or at another suitable deployment location in the sinus cavity system. This is in contrast to conventional VP or VA valves, which drain to the peritoneum or right atrium of the heart and where the differential pressure is different. The functionality of conventional shunts is also challenged by gravity and as a result these valves often incorporate programmable or other flow regulating features to try to address this. These additional features are unnecessary with embodiments of the shunt device disclosed herein and with embodiments of the methods where the outlet end of the shunt device are positioned in the jugular foramen or a venous sinus cavity. Shunt body FIGs.3A-B illustrate an example of a shunt body of an embodiment of a shunt device. FIG.3A shows a three-dimensional view of the shunt body, while FIG.3B shows a cut- away three-dimensional view of the shunt body. In various embodiments, the shunt body 3 is configured for subcutaneous placement on the calvarium of the patient. In particular, the shunt body is preferably shaped and sized for such placement. To this end, the shunt body may have a generally flat housing 31 having a thickness / height large enough to make it palpable when implanted subcutaneously. The flat housing 31 has a bottom wall 311 that, in use, faces the calvarium, and a top wall 312 of the shunt body housing faces, in use, away from the calvarium. The flat body has a circumference, which may be formed by a circumferential wall 313 extending between the top and bottom walls, or by the top and bottom walls converging towards each other, or otherwise. The shunt body has an inlet connector 32, which is preferably located at the circumference of the flat body, for fluidly connecting the tubular inlet. The shunt body has an outlet connector 33, which is preferably located at the circumference of the flat body, for fluidly connecting the tubular outlet. In some embodiments, the shunt body comprises flow restricting means 34 aimed at controlling the flow of cerebrospinal fluids through the shunt device in such a way that the flow rate of cerebrospinal fluid through the shunt device is such that the flow of cerebrospinal fluids through the shunt device is similar to the flow of cerebrospinal fluids from the ventricles and into the sagittal sinus in an individual under normal physiological conditions, i.e. conditions at which flow of cerebrospinal fluids and / or intracranial pressure conditions would be deemed physiological to the extent that insertion of a shunt device into a CSF containing space of an individual would not be contemplated or required to increase or modulate a cerebrospinal fluid flow rate or to relieve or modulate an increased intracranial pressure. The flow restriction means may be formed by a reduced diameter conduit or otherwise. In addition, or alternatively to a flow restriction means in the shunt body, the shunt device may include alternative flow restriction means, e.g. a resistance tube at the outlet end as described herein, or otherwise. The shunt body 3 preferably comprises a check valve 37 aimed at preventing back-flow of cerebrospinal fluids from the outlet end of the outlet to the inlet end of the inlet. The opening pressure of the check valve is preferably from about 2 mm Hg (i.e.2,7 cm H2O) to less than about 5 mm Hg (i.e.6,8 cm H2O), and the opening pressure of the check valve is preferably independent of the rate at which cerebrospinal fluids flow through the flow restricting means of the shunt device. In the example of FIGs.3A-B, the check valve 37 is spring loaded. The spring provides a specific opening pressure (e.g. about 3 ± 1.5 cm H2O), to correlate with the difference between intracranial pressure (ICP) and the pressure in the jugular foramen. In particular, in the illustrated embodiment, the check valve 37 is formed by a valve ball 371 which is biased against a valve seat by a flat spring element 372, e.g. a flat nitinol spring, which may be secured in the housing by a cover 373. In the example of FIGs.3A-B, the shunt body 3 comprises a control reservoir 35, formed as an antechamber to the check valve 37. The control reservoir 35 is fluidly connected with the inlet connector 32 and with the outlet connector. The present example includes two check valves 36 and 37. Check valve 36 is located between the outlet connector and the control reservoir while check valve 37 is located between the control reservoir 35 and the outlet connector 33. Both check valves may comprise a valve ball 361 and 371, respectively, such as sapphire balls or otherwise. The control reservoir 35 is a chamber defined by a bottom wall 311 of the shunt body housing 31 and an opposite soft dome-shaped wall 38 (which may be transparent to allow visual inspection of the control reservoir 35). The dome-shaped wall may be made from silicone rubber or from another suitable material. The dome-shaped wall may be held in place by a titanium ring 381 or otherwise. The control reservoir 35 allows the check valve 37 to be primed during surgery, and for the system to be verified for through-flow after surgery (e.g. through compression or water-column test). The two check valves 36 and 37 prevent backflow from the outlet end and into the ventricles. When the dome is compressed (by the surgeon), the inlet valve closes. When the dome is decompressed (when the surgeon releases pressure), the inlet valve opens and the outlet valve closes. The housing 31, including the valve seats of valves 36 and 37, the inlet connector 32, the outlet connector 33, and the cover 373 may be made from titanium or from another suitable material. Generally, the materials of the various components should preferably be medical grade, biocompatible and suitable for long-term use. The various components of the shunt body may be assembled by press-fitting them into each other or otherwise. Press fitting ensures a durable assembly without requiring adhesives, clamps, or other similar elements. Generally, shunting cerebrospinal fluids from the ventricles to the vena jugularis at the foramen jugulare, with embodiments of the shunt devices disclosed herein reduces the risk of overdrainage of cerebrospinal fluids caused by excessive differences between - the pressure in the ventricles, where the inlet opening of the shunt device is located when the tubular inlet of the shunt device has been inserted into the ventricles, and - the pressure in the vena jugularis, where the outlet opening of the shunt device is located when the tubular outlet of the shunt device has been inserted into the vena jugularis at the foramen jugulare. As described above, the shunt body of various embodiments of the shunt device preferably comprises a control reservoir. A control reservoir may have several functions. For example, it is possible to use the control reservoir as a pump. A medical practitioner will be able to ”palpate” through the skin to control whether the shunt is operational. It is possible in this way to monitor if the shunt device has become blocked at the inlet end or at the outlet end. By applying a variable and increasing force to the control reservoir, it is also possible to evaluate whether the outlet end of the shunt device has become blocked. In case the control reservoir takes a relatively long time to refill after an increasing pressure has been applied, this would be an indication that the inlet end of the shunt device has become blocked. The palpating functionality of a control reservoir may also be used to prime the shunt device prior to or during insertion. By applying a pressure to the control reservoir it may be possible to remove undesirable gaseous fluids, including air, from the shunt device. The control reservoir preferably has transparent wall sections so that gaseous fluids may be visibly detected. The control reservoir may also be used for performing riser tube tests. A medical practitioner may insert a thin needle into the control reservoir and through a silicone dome. The tube is filled with water, and the water enters the needle. The height of the rising water is indicative of the ICP. The control reservoir may also be used by a medical practitioner to evaluate or modulate for testing purposes the flow rate of cerebrospinal fluids through the shunt. Tubular outlet / venous access port (VAP) Again referring to FIG.2, FIG.2 shows the outlet end, generally designated by reference numeral 21, of a tubular outlet of an example of a shunt device. The outlet end 21 of the present examples with the attached fixator 213 is also called the venous access port (VAP). The VAP of the present examples may be manufactured from only three components, each with distinct and interesting functions: The catheter tube 22 (e.g. silicone catheter tube), the resistance tube 212, and the fixator 213, e.g. formed as a nitinol frame. The resistance tube 212 and nitinol frame 213 are at the distal end of the catheter tube 22, which discharges fluid from the shunt body of the shunt device. The function of the fixator is to support and center the outlet end with the outlet opening 211, ensuring that it does not contact the endothelium on the inside of the vein. The resistance tube 212 may be a polyetheretherketone (PEEK) resistance tube. The resistance tube may be fitted at the end of the catheter tube 22 and serve to provide built-in flow resistance. Generally, the VAP is operable to divert CSF from the shunt body to the top of the jugular vein at the jugular foramen. The resistance tube 212 may provide a stiff end to the silicone catheter tube 22 and it ensures that CSF is released into the bloodstream in a measured manner while the fixator 213 allows the catheter to be placed in the jugular vein at the point where it passes through the jugular foramen. The fixator 213 will remain where it is placed due to the expansion force of the nitinol. The neck 2131 of the fixator serves as an attachment member that secures the resistance tube 212 in the center of the fixator. The jugular foramen is a particularly suitable placement point for the fixator 213, both because it connects to the dural venous sinus where CSF normally drains and because the foramen jugulare surrounds the vein with a rigid bone structure 56 which provides a solid “tunnel” fixation for the fixator. There is also a negligible difference in elevation between the outlet and the ventricles which avoids hydrostatic pressure differences which otherwise can affect conventional shunts. Furthermore, at the point where the jugular passes through the foramen there is no movement in the vein unlike lower in the internal jugular vein. The fixator may be configured to be collapsed into an introducer with or without tear- away features so that it can easily be inserted, positioned, and then released in the jugular vein / jugular foramen. This procedure may be monitored under fluoroscopy. The hyper-flexible properties of nitinol, allow it to automatically conform to the oval shape of the jugular foramen once released from the introducer, e.g. from a tear-away introducer or other type of introducer. Once the device has been placed and connected with the shunt body, CSF will flow into the vein at a rate of approximately 0.35 ml / min against the relatively high flow rate of blood at approximately 350 ml / min in the jugular vein. Fixator for securing an outlet of a shunt device In preferred embodiments of the shunt device disclosed herein, the outlet of the shunt device comprises a fixator, e.g. as illustrated in FIG.2. The fixator may be attached to the outlet end, in particular at or near the outlet opening, and configured to secure a location of the outlet end in the venous system cavity by exerting a radial outward force onto a wall of the venous system cavity at a deployment location of the outlet end in the venous system cavity, in particular in the vena jugularis where the vena jugularis passes through the foramen jugulare. The fixator, in its expanded use state, may extend from the tubular outlet radially outwards relative to the outlet opening of the tubular outlet. The fixator, in the expanded use state, may extend radially outward from all or part of the tubular outlet. The fixator may be attached to the tubular outlet at one or more attachment locations, at least a proximal attachment location of the one or more attachment locations preferably being displaced from the outlet opening by a displacement distance. The fixator, in the expanded use state, may have a longitudinal extent defined between the proximal attachment location and a distal end of the fixator, wherein the longitudinal extent is no smaller, preferably larger, than the displacement distance. The fixator, in the expanded use state, may define a cone shape of increasing radial extent between the proximal attachment location and a distal end of the fixator. The fixator may comprise one or more fixator members, each attached to the outlet end of the tubular outlet and, at least in an operational state of the fixator, extending radially away from the outlet end towards the endothelial wall of the sinus system cavity in which the outlet end is deployed, e.g. the endothelial wall of the vena jugularis. Each of the one or more fixator members may define or be connected to one or more engagement portions. In some embodiments, more than one, e.g. all, fixator members may be connected to the same engagement portion. The one or more engagement portions may be defined as locations of maximum radial protrusion of the fixator member from the outlet end, when the fixator is in its expanded use state. In some embodiments, the engagement portion may be formed as an engagement member, such as a mesh, e.g. a frusto-conical or cylindrical mesh that is connected to the attachment member via the one or more fixator members. In some embodiments, more than one, e.g. all, fixator members may be connected to the same engagement portion or member. When the fixator is deployed in a sinus system cavity, the one or more engagement portions are configured to engage the endothelial wall of the sinus system cavity and to exert a radial outward force onto the wall of the sinus system cavity. In some embodiments, the one or more engagement portions may comprise one or more hooks or other radial outward projections configured to be pushed by the radial expansion force against the wall of the sinus system cavity at the deployment location, thereby preventing or restricting axial displacement of the fixator from the deployment location along the sinus system cavity. In some embodiments, each of the one or more fixator members is attached to the outlet end at an attachment location along the outlet end. The attachment location may be axially displaced from the outlet opening. The one or more fixator members may all be attached at the same axial attachment location or at respective axial attachment locations. The fixator members may extend radially and axially from the attachment location, e.g. radially outward and axially forward. Here the forward direction refers to the direction from the attachment location towards the outlet opening. The fixator members may axially extend from the attachment location towards and, optionally, beyond the outlet opening. The fixator may include a single fixator member or a set of more than one, such as two, three, four or even more fixator members. The one or more engagement portions of the single fixator member or of the set of fixator members may be distributed, preferably uniformly distributed, along the entire circumference of the outlet member, thereby causing the fixator to impart radial outward forces along the circumference of the endothelial wall. Each fixator member may be an elongated arm or wire, e.g. a nitinol arm or wire. A small number of radially extending arms reduces the cross-sectional obstruction caused by the deployed fixator. The fixator may comprise connector members capable of interconnecting one or more fixator members, such as connector members capable of interconnecting two or more, such as at least three fixator members. The fixator can be in the form of an expandable, resilient mesh comprising, e.g., at least two or three engagement portions defining maximum radial protrusions of the resilient mesh from the outlet, when the fixator is in its expanded use state. The resilient mesh preferably comprises a superelastic and / or hyperelastic material, such as, e.g., nitinol. By providing a fixator comprising a resilient yet superelastic and / or hyperelastic mesh, a more resilient structure of the fixator is achieved, and this in turn provides more stability and increased ability for spanning cavities of the jugular foramen having irregular shapes. The superelastic and / or hyperelastic mesh should be sufficiently coarse so that it does not significantly impair the passage of fluids through the sinus system cavity, in particular the vena jugularis at the foramen jugulare, e.g. att the jugular bulb, during use of the shunt device. The fixator is flexible, preferably superelastic and / or hyperelastic, and when the fixator is in the expanded use state, it extends outwardly from all or part of the tubular outlet. The fixator in an outwardly expanded use state preferably secures the tubular outlet comprising the outlet end and the outlet opening in the venous system cavity where it is deployed, e.g. in a sinus cavity system or the vena jugularis. When deployed in the foramen jugulare and when in its outwardly expanded use state, the fixator preferably secures the tubular outlet comprising the outlet end and the outlet opening in the foramen jugulare by exerting a force on the boundaries or bone structures defining a foramen jugulare cavity in the individual in which the tubular outlet is located after inserting and guiding through the vena jugularis. The fixator may exert the force via the wall of the vena jugularis in which the outlet end is deployed. The radial force exerted by the fixator onto the walls of the sinus system cavity, which it is deployed in, e.g. onto the foramen jugulare cavity, may be a balanced radially orientated spring force. The radial spring force is sufficient to expand the fixator from its compacted state, in particular responsive to being released from an introducer that constrains the fixator to its compacted state. The radial spring force is sufficient to cause the fixator to adopt its expanded use state in which the fixator adapts its shape to the irregular circumferential cavity wall of the sinus system cavity at the deployment location and exerts a radial force onto the cavity wall. The radial force is sufficient to expand the fixator from a compacted state to a fully expanded state when the fixator is not confined by any outer walls. In some embodiments, in such an unconstrained, fully expanded state, the diameter of the fixator is from about 10 mm to about 15 mm, such as for example 12.5 mm. The radially orientated spring force is also sufficient to secure and maintain the location and orientation of the fixator when deployed in the foramen jugulare and when in its expanded use state. In the expanded use state, the fixator is partly expanded but still constrained by the walls of the vena jugularis and by the walls of the foramen jugulare. The fixator is operable to adapt its shape to the lumen it is deployed in. The foramen jugulare has a noncircular shape. Typically, the foramen jugulare has a cross-sectional wall-to-wall distance of between 6 mm - 7 mm along one direction and a cross- sectional wall-to-wall distance of about 12 mm - 15 mm along another direction. It will be appreciated that the shape and size of the foramen jugulare may vary from individual to individual. The radial force, in particular the radial spring force, exerted by the fixator in its deployed state on the sinus cavity it is deployed in is balanced and limited in such a way that it does not cause the fixator to penetrate the endothelial wall of the sinus system cavity it is deployed in, e.g. the endothelial wall of the vena jugularis in the foramen jugulare. When the fixator is for deployment in the foramen jugulare, the radial force is selected such that it does not affect the nerves that are located in the foramen jugulare. The radial force, in particular the radial spring force, is preferably from about 0,5 Newton to about 1,5 Newton, such as about 0.7 Newton, for example about 0.9 Newton, such as about 1.0 Newton, for example about 1.1 Newton, such as about 1.3 Newton, in the compacted state when the fixator is compacted in an introducer during insertion or retraction. The radial force, in particular the radial spring force, is preferably from about 0.1 Newton to 1.0 Newton in an expanded use state when the fixator is deployed in a sinus system cavity, in particular in the foramen jugulare, such as between 0.1 Newton and 0.8 Newton, such as between 0.1 Newton and 0.5 Newton, such as between 0.2 Newton and 0.5 Newton ,such as about 0.2 Newton, for example about 0.3 Newton, such as about 0.4 Newton. In the expanded use state, the fixator is typically partly compacted compared to a fully expanded state to which the fixator expands when not constrained in a lumen. In some embodiments, in the unconstrained, fully expanded state, the diameter of the fixator is from about 10 mm to about 15 mm, such as for example about 11 mm, for example about 12 mm, such as about 13 mm, for example about 14 mm. In one embodiment, in the unconstrained, fully expanded state, the diameter of the fixator is 11.7 mm. In some embodiments, in the expanded use state, i.e. when deployed in a sinus cavity system, such as in the foramen jugulare, the fixator may have a diameter, at least along one transverse direction, of between 3 mm and 9 mm, such as between 4 mm and 8 mm, such as between 5 mm and 7 mm, e.g. about 5 mm, or about 6 mm or about 7 mm. When the fixator is deployed inside a non-circular cavity, e.g. in the foramen jugulare, the fixator may adopt an irregular shape with a non-circular cross- section. The diameter of the fixator in the expanded use state may thus be defined as the diameter of an inscribed circle around the geometric centre of the cross section, i.e. as the length of the shortest line passing through the geometric center of the cross section between two points on the circumference of the fixator. The diameter may be determined at a longitudinal position along the fixator where the fixator has its largest radial extent. In some embodiments, the radial spring force may be measured by measuring the force required to compact the fixator between two parallel plates to a nominal diameter, the nominal diameter corresponding to the diameter of the fixator when deployed in the sinus cavity system at the intended deployment site, e.g. in the foramen jugulare. Accordingly, in some embodiments, the radial spring force measured as a force required to compact the fixator between two parallel plates arranged parallel to the longitudinal axis of the fixator to a plate-to-plate distance of 6 mm, is preferably from about 0.1 Newton to 1.0 Newton, such as between 0.1 Newton and 0.8 Newton, such as between 0.2 Newton and 0.5 Newton ,such as about 0.2 Newton, for example about 0.3 Newton, such as about 0.4 Newton. In some alternative embodiments, the fixator may be made from a plastically expandable material, e.g. a balloon or the like. When the fixator is in the outwardly expanded use state and secured in the foramen jugulare, the tubular outlet comprising the outlet end, and the outlet opening is preferably secured in the foramen jugulare essentially in a retrograde orientation with respect to the flow of blood through the vena jugularis, i.e. the flow direction of the CSF exiting the outlet opening is opposite to the flow direction of the blood flow in the vena jugularis. The fixator, in its outwardly expanded use state, preferably maintains the tubular outlet comprising the outlet end and the outlet opening at least at a predetermined minimum distance from the endothelial wall of the sinus system cavity it is deployed in, e.g. from the endothelial wall of the vena jugularis in the foramen jugulare. In the expanded use state, the flexible, preferably superelastic and / or hyperelastic, fixator is configured to adopt an irregular shape, such as, e.g., a non-circular shape that reflects the corresponding irregular shape of the foramen jugulare. The superelastic and / or hyperelastic fixator may, e.g., comprise a nitinol frame. It is beneficial that the fixator is configured to adopt an irregular shape that corresponds to the irregular shape of the foramen jugulare cavity in which the fixator is located when in the expanded use state. By adopting an irregular shape that corresponds well to the irregular shape of the foramen jugulare, the contacting between the fixator and the foramen jugulare cavity into which it is inserted, e.g. the jugular bulb or other part of the vena jugularis, becomes evenly distributed and the flow of blood in the vena jugularis is minimally affected. The fixator may be provided with one or more than one set of fixator members, and each set of fixator members may be arranged to protrude from the tubular outlet at different and / or predetermined distances from the outlet opening of the outlet. Different sets of fixator members provide an increased stability to the fixator, and each set may have the same or a different number of fixator members. Foramen jugulare and bulbus superior venae jugularis Various embodiments of the device and method disclosed herein provide shunting of cerebrospinal fluids to a venous system cavity of an individual, including a human being. The venous system cavity may be a sinus system cavity of the venous sinus system of the individual. In particular, various embodiments of the device and method disclosed herein provide shunting of cerebrospinal fluids to the vena jugularis of an individual, including a human being. In particular, various embodiments of the device and method disclosed herein provide shunting of cerebrospinal fluids to an outlet location inside the upper vena jugularis, where the outlet location is located at a position where the vena jugularis passes through the foramen jugulare of the individual. In particular, the outlet opening may be secured in or otherwise to the foramen jugulare. In some embodiments, at least a portion of the outlet end and / or the fixator may extend into the bulbus superior venae jugularis located immediately above the foramen jugulare. FIG.4 illustrates the dural venous sinus system of a human patient. In particular, FIG. 4 illustrates the internal jugular vein (vena jugularis) 52, the jugular bulb 54, the sigmoid sinus 55, the transverse sinus 57, the straight sinus 581, the superior sagittal sinus 582, and the inferior sagittal sinus 583. For the purpose of the present disclosure, the upper end of the vena jugularis is considered to be part of the venous sinus system, i.e. the term “sinus system cavity” as used herein, is intended to include at least the uppermost part of the vena jugularis, where the vena jugularis extends through the jugular foramen and / or above the part of the vena jugularis that can partly collapse when the individual is in an upright body position (thereby affecting the pressure like a Startling resistor). Other examples of a sinus system cavity include the jugular bulb, the sigmoid sinus and the transverse sinus. The internal jugular vein, which is also referred to simply as the jugular vein or the vena jugularis throughout this document, is a paired vein that collects blood from the brain and the superficial parts of the face and neck. The internal jugular vein begins in the jugular foramen, at the base of the skull, in particular in the posterior compartment of the foramen jugulare. It is somewhat dilated at its origin, which is called the superior bulb. It runs down the side of the neck in a vertical direction, and at the root of the neck, it unites with the subclavian vein to form the brachiocephalic vein (innominate vein). The jugular foramen is a large opening located at the posterior end of the petro- occipital suture between the jugular process of the occiput and the petrosal portion of the temporal bone. It serves as a passage for the glossopharyngeal nerve, vagus and accessory nerves, as well as the internal jugular vein. As can best be seen in FIG.1B, at the foramen jugulare 53, in particular at the jugular bulb 54 immediately superior to the foramen jugulare, the vena jugularis 52 is connected to the sigmoid sinus 55 at one end of the sigmoid sinus, and the sigmoid sinus is connected at the other end thereof to the transverse sinus. The sigmoid sinus therefore connects the transverse sinus with the jugular vein. The vena jugularis passes through the base of the skull through the jugular foramen. The vena jugularis is completely surrounded by bone in the tunnel (foramen jugulare) through the skull, except from a part of the anterior wall where hard fibrous tissue covers the vagus nerve. The pars venosa (or pars vascularis) is situated in the posterolateral aspect of the jugular foramen and contains the internal jugular vein (IJV), the posterior meningeal branch of the ascending pharyngeal artery, the vagus nerve (cranial nerve X), the auricular branch of the vagus nerve (Arnold’s nerve), and the spinal accessory nerve (cranial nerve XI). A smaller pars nervosa is located in the anteromedial portion of the jugular foramen and contains the glossopharyngeal nerve, the tympanic branch of the glossopharyngeal nerve (Jacobsen’s nerve), and the inferior petrosal sinus. Both the pars venosa and the smaller pars nervosa contain neural as well as vascular entities and structures. The walls of the jugular foramen are formed anterolaterally by the petrous bone and posteromedially by the occipital bone. The foramen is directed in an anterior, lateral, and inferior direction. The diameter of the jugular vein in the foramen is typically in the range 7 of from 10 mm. In rare cases, the foramen has been observed to have a diameter below 3 mm. The largest reported size of the vein is 14 x 7 mm. According to morphometric studies, the osseous jugular foramen can be more accurately described as a triangular canal with an endocranial (~14.5 × 7 mm) and an exocranial opening (~9 × 17 mm). It lies about 23 mm medial to the apex of the mastoid tip, 15 mm medial to the tympanomastoid suture, and 5 mm above the intracranial orifice of the hypoglossal canal. The walls of the venous sinus are tightly connected to the bone-surface (periost). The walls cannot be penetrated in this area. The tympanic nerve (Jacobson’s nerve) passes in a canal in the anteromedial part of the jugular fossa. It is contained in its own canal, in 20% fully enclosed in bone, else covered by dura mater. A branch of the vagus nerve (cranial nerve X) passes through the anterior-medial part of the jugular foramen. A continuation of the dura separates - as a fibrous membrane - the nerve from the jugular vein. The jugular vein in the foramen jugulare cannot be penetrated or even pushed outwards by a fixator described herein when such a structure, for example in the form, e.g., of an expandable, resilient and super- and / or hyperelastic mesh, is inserted into and expanded into a use state in the foramen jugulare. The walls of the foramen jugulare cannot be penetrated, except from the antero-medial fibrous wall, and in such case only by sharp instruments. Hence, a fixator comprising, e.g., an expandable, resilient and super- and / or hyperelastic mesh, may contact, but not penetrate, the walls of the vena jugularis inside the foramen jugulare when the outlet end of a shunt device according to various embodiments disclosed herein is inserted into the vena jugularis inside the foramen jugulare and expanded into an expanded use state. Immediately below the jugular foramen, the vena jugularis may be surrounded by cartilage of other stiff tissue. Accordingly, a deployment position of the outlet end immediately below the jugular foramen may also be suitable. Generally, the outlet end may be located inside the top of the vena jugularis, such as the top 3 - 4 cm of the vena jugularis. Such a deployment position and, in particular, a deployment position immediately below the jugular foramen where the vena jugularis is surrounded by stiff tissue, may be regarded as a deployment position at the jugular foramen. A deployment position where at least a portion of the fixator is located inside the jugular foramen may be preferred, as the vena jugularis may have a relatively large diameter below the skull. Generally, a deployment position where the outlet opening and / or at least a portion of the fixator is / are located inside the jugular foramen, may be considered a deployment position in the jugular foramen. In some situations, a part of the fixator may be located inside the jugular foramen while another portion of the fixator may be located immediately above and / or below the jugular foramen. It is generally preferred that the fixator is located at a position along the vena jugularis high enough to avoid the pulsating of the vena jugularis. It will be appreciated that there are two jugular veins and two jugular foramen, a left one and a right one. A deployment position in both is possible. However, in most situations a position in the right jugular foramen may be preferred, as the right jugular foramen is often larger. The sigmoid sinus has an s-shaped curve along the internal wall of the occipital bone and continues upward in the transverse sinus. The roof of the sinus, inside the skull, above the bony tunnel, is part of the dura mater, a strong surface of fibrous tissue that is only permeable by a sharp instrument. It is not possible to penetrate the wall with a guidewire or an introducer sheath. The jugular foramen, including the portion of the vena jugularis immediately below the jugular foramen, where the vena jugularis is surrounded by stiff tissue, offers an optimal site for the placement of a venous access port according to various embodiments disclosed herein. The cavities of the jugular foramen are not collapsible, their forms remain independent of external forces and venous pressure, and the walls can only be perforated by sharp instruments. Once inserted into the foramen jugulare, a fixator, such as, e.g., a nitinol frame may be expanded to a predetermined size. This expansion will exert a certain pressure on the surroundings, including wall sections of the foramen jugulare. The expansion-force of a fixator, e.g., a nitinol fixator, placed in the jugular vein inside the jugular foramen, must be sufficient to keep the fixator in place. However, the wall of the vein is attached to bone except for the antero-medial part, where the nerves are situated. The nerves are separated from the vein, as mentioned above, by a sheath of dura, and in some cases by an osseous crista. The flexible geometry of the hyperelastic materials from which the fixator may be manufactured will ensure that the pressure exerted by the expanded fixator is essentially evenly distributed over and around the internal area of the jugular vein in the foramen jugulare. The internal wall of the foramen jugulare is covered by endothelium. Endothelium is a layer of active cells, and in the arterial system, the cells react quickly when exposed to foreign objects or when the inner wall is penetrated or scarred by instruments. Arterial intravascular stents become overgrown or embedded by this layer of cells. This is probably also the case in the venous system. Experiences gained from clinical trials involving replacement of drains in the transverse sinus indicate that drains became encapsulated at the internal wall of the vein. However, stents placed in the transverse sinus, e.g., in a treatment of a narrowed sinus that results in intracranial hypertension, remain patent for years. Despite being both structurally rigid and of an irregular shape, the present inventor has surprisingly found that it is advantageous to locate and secure an outlet end of a tubular outlet of a sinus system catheter of a shunt device within the irregularly shaped cavities of the foramen jugulare. Using the irregularly shaped cavities of the foramen jugulare for the insertion into the sinus system of an outlet end of a tubular outlet makes it possible for a medical practitioner to monitor and control the process of inserting the shunt device. An outlet end of a tubular outlet of a shunt device according to various embodiments disclosed herein is inserted into the vena jugularis by known surgical procedures, and the outlet end of the tubular outlet is actively guided upwards through the vena jugularis to the foramen jugulare in a retrograde orientation, i.e. against the direction of the flow of blood through the vena jugularis. The tubular outlet of the shunt device preferably comprises a fixator which is in a compacted state during insertion or retraction from the vena jugularis, including into the foramen jugulare, and in an expanded use state after having been inserted into the vena jugularis and located in an irregularly shaped cavity of the foramen jugulare. When cerebrospinal fluids are drained from the ventricles to the vena jugularis at or inside the foramen jugulare, the fixator is expanded into and essentially spans and exerts a radial force onto irregularly shaped cavities of the foramen jugulare. The fixator is preferably made from a superelastic material or an alloy that is sufficiently flexible to adopt the shape of the irregular cavities of the foramen jugulare. Nitinol is an example of a superelastic material that may be used for manufacturing the fixator. Methods of shunting cerebrospinal fluids to the foramen jugulare The brain and spinal cord are encased in the cranium and vertebral column inside a thin membrane known as the meninges. The space within the meninges includes, among others, the ventricles, and cerebrospinal fluids are produced in the chorioid plexus of the ventricles at a rate of 0.3 to 0.4 ml / min under normal conditions. The cerebrospinal fluids flow through the ventricles, aqueduct and basal cisterns over the cerebral surface to the arachnoid villi, and the cerebrospinal fluids are absorbed from the arachnoid villi into the sagittal sinus. The sagittal sinus is connected to the transverse sinus and the sigmoid sinus. Cerebrospinal fluids enter the vena jugularis from the sigmoid sinus via the foramen jugulare. In one embodiment there is provided a method of shunting cerebrospinal fluid from the ventricles to the foramen jugulare of an individual suffering from elevated intracranial pressure. Shunt devices capable of being used in this method comprise a tubular inlet having an inlet end with an inlet opening configured for insertion into the ventricles of an individual, a shunt body, and a tubular outlet having an outlet end with an outlet opening configured for insertion into the vena jugularis at the foramen jugulare. The shunt device diverts CSF from the ventricles of the brain to the jugular foramen, at the point where the sigmoid sinus meets the internal jugular vein. Various embodiments of this method are based on the principle that there is a positive and physiological differential pressure (DP) between the shunt inlet (ventricles of the brain) to the shunt outlet (the jugular foramen) that drives CSF to flow into the systemic blood circulation. The principle of operation of the shunt device may be based on a spring-loaded ball-in- cone valve and a flow restricting element. The shunt device may be a passive system which avoids hydrostatic pressure differences usually found when shunting from the ventricles of the brain to the peritoneum or right atrium of the heart. In various embodiments, the method comprises the steps of: a) inserting at least a part of the inlet end of the tubular inlet, the inlet end comprising the inlet opening, into the ventricles or a subarachnoid space of an individual, b) inserting at least a part of the outlet end of the tubular outlet, the outlet end comprising the outlet opening, and a fixator in a compacted state into the vena jugularis of the individual, c) guiding the outlet end of the tubular outlet and the fixator in a compacted state through the vena jugularis towards the foramen jugulare, d) locating the outlet end of the tubular outlet, the outlet end comprising the outlet opening, and the fixator in a compacted state in a cavity of the foramen jugulare essentially in a retrograde orientation, and e) changing the state of fixator from the compacted state to an expanded use state, wherein the fixator in the expanded use state exerts a force on foramen jugulare cavity wall sections, thereby securing the tubular outlet comprising the outlet opening in a predetermined position away from the wall sections in the foramen jugulare cavity. When methods of shunting cerebrospinal fluid from a cerebrospinal fluid containing space of an individual to the foramen jugulare of the individual comprise the steps of i) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, ii) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the foramen jugulare of the individual, and iii) shunting cerebrospinal fluid from the cerebrospinal fluid containing space of the individual to the foramen jugulare, e.g. including the jugular bulb, of the individual, the individual typically suffers from elevated intracranial pressure, such as, e.g., hydrocephalus, including normal pressure hydrocephalus, and it is thus necessary to shunt cerebrospinal fluids from a ventricle or a subarachnoid space of the individual, including a human being, to the sinus system cavity, including the vena jugularis at the foramen jugulare. In one embodiment, there is provided a method of inserting a cerebrospinal fluid shunt device in a cerebrospinal fluid containing space and in the foramen jugulare of an individual. The method comprises the steps of a) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, b) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the foramen jugulare of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening inserted into the foramen jugulare of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening. The outlet end of the tubular outlet comprising the outlet opening is initially inserted into the vena jugularis and guided through the vena jugularis and into the foramen jugulare and secured in the foramen jugulare by a fixator comprised by, or attached to, the tubular outlet. The fixator securing the tubular outlet comprising the outlet end and the outlet opening in the foramen jugulare is converted from a compacted state into an expanded use state to secure the tubular outlet comprising the outlet end and the outlet opening in the foramen jugulare. The fixator is flexible, preferably superelastic and / or hyperelastic, and the fixator in the expanded use state extends outwardly from all or part of the tubular outlet. The fixator in the outwardly expanded use state secures the tubular outlet comprising the outlet end and the outlet opening in the foramen jugulare by applying or exerting a force on the boundaries or bone structures defining a foramen jugulare cavity, including the upper vena jugularis or jugular bulb, in which the tubular outlet is located after having been inserted into and guided through the vena jugularis. The fixator in the outwardly expanded use state secures the tubular outlet comprising the outlet end and the outlet opening in the foramen jugulare essentially in a retrograde orientation with respect to the flow of blood through the vena jugularis, and the fixator maintains the tubular outlet comprising the outlet end and the outlet opening at least in a predetermined minimum distance from the endothelial wall of the vena jugularis in the foramen jugulare. In one embodiment, a method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in foramen jugulare of an individual comprises the steps of a) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, b) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into a foramen jugulare of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening inserted into the foramen jugulare of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening, wherein the inlet opening inserted into the cerebrospinal fluid containing space of the individual and the outlet opening inserted into the foramen jugulare of the individual are operably connected by a shunt body connected at one end to the tubular inlet having an inlet end with an inlet opening configured for insertion into the ventricles of an individual, and connected at another end of the shunt body to the tubular outlet having an outlet end with an outlet opening configured for insertion into the vena jugularis at the foramen jugulare of the individual, d) guiding the tubular outlet comprising the outlet end and the outlet opening through the vena jugularis towards the foramen jugulare, e) locating the tubular outlet comprising the outlet end and the outlet opening in a cavity of the foramen jugulare, and f) changing the state of the fixator from a compacted state to an expanded use state, wherein the fixator in the expanded use state applies or exerts a force on a foramen jugulare cavity and maintains the tubular outlet comprising the outlet end and the outlet opening in an essentially fixed position in the foramen jugulare away from and with a minimum distance to endothelial tissue of the vena jugularis. The insertion of the shunt device disclosed herein may be performed as follows: A ventricular catheter may be inserted into a cerebral ventricle, e.g. the right or left frontal horn of the cerebral ventricles, via pre-coronal burr hole, and connected to the subcutaneously placed shunt body including the control reservoir and one-way valve. The outlet end of the tubular outlet of the shunt device, including the fixator, may be collapsed into a suitable introducer, e.g. a standard introducer, and inserted into the jugular vein at a penetration point at the patient’s neck. To this end, the Seldinger technique may be used to insert the introducer (e.g. using a guidewire, dilator, and peel-away sheath) into the vena jugularis. The introducer containing the device may be inserted through a peel-away sheath and then radiographically guided as far as the junction between the sigmoid sinus and top of the vena jugularis before the fixator (e.g. a nitinol frame / mesh) is released and expanded in the jugular foramen. The silicone catheter of the tubular outlet may then be connected to a unidirectional fixed pressure valve before being led subcutaneously to the shunt body. The correct position of the outlet end may be confirmed by a final radiograph. The device and accessories can also be observed in a CT scan. FIGs.5A-D illustrate a process for insertion of the outlet end of the tubular outlet (VAP) into the foramen jugular of a patient. Generally, the outlet end of the tubular outlet may be inserted at an access location into the vena jugularis. The outlet end of the tubular outlet inserted into the vena jugularis may then be guided in a cranial direction through the vena jugularis to the deployment location at the foramen jugulare, e.g. to the junction between the sigmoid sinus and the top of the vena jugularis. The outlet end may be secured at the deployment location by a fixator attached to the tubular outlet. The insertion of the outlet end (VAP) may be performed using the Seldinger technique, the same standard vascular access technique which is used for placing the distal drainage catheters of conventional VA shunts. The difference between the two placement methods is that, in VA catheter placement, the distal drainage catheter is guided downwards into the atrium of the heart of the patient (about 20 cm from the insertion point) whereas, with the shunt device disclosed herein, the outlet end is guided upwards to the jugular foramen (about 10 cm from the insertion point). As with VA catheter placement, the placement of the VAP may be monitored through fluoroscopy. FIG.5A illustrates the tip of a peel-away sheath 80 being guided through the jugular vein 52 up to the jugular foramen just below the jugular bulb 54. FIG.5B illustrates that, when the tip of the tear-away sheath 80 has been advanced to, and is located in, the jugular foramen, the tear-away sheath 80 is retracted, and the fixator 213 expands, e.g. due to the spring-force of the nitinol material. FIG.5C illustrates the deployed outlet end 21 after the introducer 80 has been further retracted. The fixator 213 has adjusted to the geometry of the jugular foramen (normally oval shaped). FIG.5D shows a peroperative x-ray with the outlet end put in place. The surgeon can monitor the positioning of the tear-away sheath and VAP using fluoroscopy. In FIG.5E, the VAP has just been released, and the introducer is being retracted. The left arrow indicates the resistance tube of the VAP, while the right arrow indicates tip of the retracted introducer sheath. Methods of shunting cerebrospinal fluids via the vena transversa FIG.6 illustrates an example of a method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in the vena transversa of an individual. According to some embodiments, when using an embodiment of the shunt device disclosed herein, the vena transversa or sigmoid sinus may serve as an alternative drainage site when shunting CSF from a CSF containing space, such as from the ventricles. To this end, the inlet end of the tubular inlet may be inserted into the CSF containing space, e.g. into a ventricle of the patient, as described herein. The outlet end 21 of the tubular outlet 2 may be inserted into the vena transversa 57, via a burr hole 515 at the back of the cranium and via a penetration point of the sinus transversus. The outlet end 21 with the fixator 213 may then be advanced to, and deployed in the vena transversa 57 or the sigmoid sinus 55. In this embodiment, the outlet end 21 is oriented in an antegrade orientation, i.e. such that the outlet flow from the outlet end is along the flow direction of the blood flow through the vena transversa or the sigmoid sinus. The CSF flow discharged from the outlet then follows the blood flow through one of the internal jugular veins 52. When the outlet end includes a fixator 213 as described herein, the risk of clogging the outlet opening by overgrowth of endothelium tissue is reduced. In one embodiment, a method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in the vena transversa of an individual comprises the steps of a) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, b) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the vena transversa, preferably via a burr hole in the vicinity of the vena transversa of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening inserted into the vena transversa of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening, d) guiding the outlet end and the outlet opening through the vena transversa towards a deployment site in the vena transversa or sigmoid sinus, e) locating the outlet end and the outlet opening at the deployment site, and f) changing the state of the fixator from a compacted state to an expanded use state, wherein the fixator in the expanded use state applies or exerts a force on a wall of the vena transversa or sigmoid sinus and maintains the outlet end and the outlet opening in an essentially fixed position in the vena transversa or sigmoid sinus and with a minimum distance to endothelial tissue of the vena transversa or sigmoid sinus. The inlet opening inserted into the cerebrospinal fluid containing space of the individual and the outlet opening inserted into the vena transversa of the individual are operably connected by a shunt body connected at one end to the tubular inlet having an inlet end with an inlet opening configured for insertion into the ventricles of an individual, and connected at another end of the shunt body to the tubular outlet having an outlet end with an outlet opening configured for insertion into the vena transversa of the individual. Methods of extracting an outlet end of a shunt device from a sinus cavity system There may be situations when the outlet end of the shunt device disclosed herein may need to be extracted again after having been implanted to a deployment location in the sinus system cavity. In some situations, only the outlet end is to be removed while, in other situations both the outlet end and the inlet end, or even the entire shunt device are to be removed. Various embodiments of the shunt device disclosed herein allow for an easy extraction of the outlet end. Generally, the extraction of a previously implanted outlet end from its deployment location may be performed by performing the steps of the insertion method, e.g. the method described in connection with FIG.5A-D above, in reverse order. FIG.7 illustrates an example of a method of extracting an outlet end of a shunt device from a sinus cavity system of an individual. The removal procedure may utilize a suitable extraction sheath 90. The extraction sheath may be sized and shaped to be inserted into the sinus system cavity where the outlet end is deployed, e.g. into the vena jugularis, and the extraction sheath may have an inner lumen large enough to accommodate the outlet end, including the fixator in its compacted state. The extraction sheath may be advanced along the sinus system cavity with the flexible tubular catheter 22 of the outlet end penetrating through the inner lumen of the extraction sheath 90. When the distal open end 901 of the extraction sheath reaches the fixator 213, further advancement of the extractor sheath, e.g. while applying a suitable pull force to the flexible tubular catheter, releases the fixator from the surrounding endothelium tissue and forces the expanded fixator into its compacted state so that the flexible tubular member with the fixator can be withdrawn inside the extractor sheath 90. If the fixator has become overgrown by endothelium tissue, as illustrated in FIG.7, it may be necessary to release or free the fixator from the wall of the sinus cavity. To this end an extractor sheath 90 may have a distal open end 901 that is configured to aid loosening of the fixator 213 from the cavity wall, e.g. when the outer portion of the fixator has become overgrown by endothelium tissue. To this end, the open end 901 may be slanted and / or include a metal tip, e.g. a multi-sided, threaded, corrugated or otherwise irregularly shaped or textured edge that aids releasing of the fixator from endothelium tissue when the extractor sheath is rotated around its own longitudinal axis. To this end, the extractor sheath may be advanced as an inner sheath inside an outer support sheath. The rotation of the extractor sheath around its longitudinal axis may be performed manually or by means of a mechanical dilator where the extractor sheath is mounted on a pistol that mechanically rotates the sheath. Examples of suitable extractor sheaths include the SteadySheath® by Cook Medical or the Evolution ® RL rotational TLE system by Cook Medical that includes an outer sheath and an inner extractor sheath with a multi-sided metal tip. The inner sheath has a handle trigger-driven rotational tip at the end. This inner sheath is mounted on a pistol that mechanically rotates the inner sheath. In some embodiments, the extractor sheath may be used in combination with a snare. Examples The following examples should not be construed as limiting the scope of protection conferred by the patent claims. Example 1 The results reported herein below are a continuation of a Danish study from 20028in which 150 patients were operated on using ventriculosinus (VS) shunts and showed immediate clinical benefit until issues were discovered with the outlet. The outlet, which at the time was a simple silicone catheter, had drifted to the side of the vein and had become enveloped by endothelial growth within 3 months. Embodiments of the shunt device described herein specifically aim to overcome these earlier failings. At least some embodiments of the shunt device disclosed herein are configured for placement in the foramen jugulare and provide an opportunity for examining novel methods of shunting cerebrospinal fluids. The primary objective of the study reported below was to test the new experimental outlet device for patency for 6 months. Approval and Ethical Consideration All experiment protocols were approved by the Regional Committee on Health Research Ethics for the Capital Region of Denmark as well as the Danish Medicines Agency. The Regional Committee on Health Research Ethics for the Capital Region of Denmark is based on the second Declaration of Helsinki and all procedures were conducted in accordance with those guidelines and regulations. Informed consent was obtained from all participants. The study was conducted following the Guidelines for Good Clinical Practice and was monitored by an independent good clinical practice monitor. Study Design and Patient Population The study was a prospective interventional single-arm, single-center open-label pilot study performed at Odense University Hospital, Denmark, on adult patients (≥ 18 years old) in need of shunting for hydrocephalus. Twelve patients were included. Inclusion criteria were the following: 1) a need for shunting, 2) MR or CT venography showing venous cross flow between the right and left transverse sinus, 3) normal lung perfusion scintigraphy, and 4) normal blood coagulation status (international normalized ratio [INR], activated partial thromboplastin time [APTT], thrombocyte count). Exclusion criteria were pregnancy and failing to meet the above inclusion criteria. The primary endpoint was that the device should remain patent for at least 6 months and the secondary endpoint was clinical outcome based on gait, cognitive dysfunction, and urinary incontinence. There were four defined time points in the study: 1) preoperative with medical examinations as per inclusion criteria, 2) surgery using the investigational device and accessories as described below, 3) 3- month follow-up at the outpatient clinic in which the patency of the device was tested, and 4) 6-month follow-up at the outpatient clinic in which the patency of the device was tested and MRI / CT and lung scintigraphy were also performed. Imaging Methodology MR or CT venography was used to verify the connections between the transverse sinus and sigmoid sinus so that drainage from the sagittal sinus would not be impeded if one of the internal jugular veins became obstructed. Only patients, who met this requirement were included in the study because in some cases the anatomy can vary. This was a precaution, e.g., if placement of the device in the right jugular caused occlusion, then venous outflow could divert from the sagittal sinus to the left jugular vein and vice versa. MRI or CT was used to determine 1) lack of over-drainage, defined by the absence of subdural hematomas or fluid collections and absence of collapse of the ventricles; and 2) lack of local thrombus formation or endothelial proliferation. CT scans were standard of care at 1 month and MRI or CT scans were performed as part of the study at 6 months. Lung scintigraphy was used to determine the possible presence of lung emboli preoperatively and at 6 months Surgical Procedure A standard ventricular drain was inserted in the right or left frontal horn of the cerebral ventricles via pre-coronal burr hole and connected to the subcutaneously placed control reservoir and one-way valve. The newly designed protective nitinol frame on the silicone catheter of the investigational device collapses into a standard introducer. The Seldinger technique was then used to insert the guidewire, dilator, and Peel-Away sheath (Cook Medical) into the vena jugularis. The introducer containing the device was inserted through the Peel-Away sheath and then radiographically guided as far as the junction between the sigmoid sinus and top of the vena jugularis before the nitinol frame was released and expanded in the jugular foramen. The silicone catheter of the device was then connected to the unidirectional fixed pressure valve before being led subcutaneously to the unidirectional valve control reservoir. The correct position of the investigational device was confirmed by a final radiograph. The device and accessories can also be observed in a CT scan. Aspirin Use Anti-platelet therapy (aspirin, 75 mg / day) was administered for 8 weeks after shunt implantation due to the possibility of the fixator or distancer provoking an endothelial reaction leading to platelet aggregation when it was released in the jugular foramen. Platelet inhibition using aspirin reduces endothelial dysfunction and platelet aggregation and thereby diminishes thrombus formation.9Once the endothelium had accommodated the nitinol frame and the inflammatory reaction had ceased, the risk of thrombus formation was considered minimal. Water Column Test The water column test was performed at 3 and 6 months postoperatively by penetrating the silicone dome of the control reservoir with a slim cannula (0.6-mm diameter) coupled to a transparent tube containing sterile physiological saline solution. This cannula was inserted percutaneously into the control reservoir. Keeping the tube in a vertical position, the fluid flows into the drain and passes through the device if it is patent. Free in-flow is defined as continuous steady flow of saline solution from an approximately 20-cm height to an approximately 5-cm height. The pressure in the control reservoir reflects the pressure in the ventricles (ICP). The control reservoir has a one-way valve with zero opening pressure, therefore the pressure measured by the water column test is, in this way, the same as that of the ventricles. Investigational Device and Shunt Accessories Since the purpose of the investigational device was to support drainage of CSF from the ventricles into the intracranial venous sinus as part of a shunt system, complementary off-the-shelf shunt accessories were required. Both the investigational device and the CE-marked accessories were provided by CSF-Dynamics A / S. Again referring to FIG.2, FIG.2 shows the outlet end 21 of a tubular outlet of an example of a shunt device. The outlet end 21 of the present example is also called the venous access port (VAP) and is manufactured from only three components, each with critical functions: The silicone catheter 22, resistance tube 212, and nitinol frame 213. The resistance tube 212 and nitinol frame 213 are at the distal end of the catheter, which diverts fluid from the complementary valve. The function of the frame is to support and center the outlet, ensuring that it does not contact the endothelium on the inside of the vein. The function of the polyetheretherketone (PEEK) tube 212, fitted at the end of the catheter, is to provide built-in flow resistance. The flow resistance in the assembled VS shunt is critical to maintain normal ICP and avoid over-drainage. The resistance tube is proportioned to achieve resistance of 10mm Hg / ml / min following the Davson equation10,11.The accessories comprised a standard ventricular drain, control reservoir with unidirectional valve, and fixed-pressure unidirectional valve. The function of the main unidirectional valve with built-in control reservoir was to allow verification of patency, and the purpose of the secondary unidirectional fixed opening pressure valve was to ensure backflow did not occur. Results Twelve patients diagnosed with normal pressure hydrocephalus (NPH) aged between 66 and 82 years were treated with a standard ventricular drain, standard control reservoir with unidirectional valve, standard fixed-pressure unidirectional valve, and the investigational outlet device positioned at the junction of the jugular foramen and the sigmoid sinus. 6-Mo FU 3-Mo Shunt Water Pt FU: Flow Colu Lung Vein Nerv Gait Dementia N Shunt Test, mn Scintigrap Occlusi e Improveme Improveme Comment o. Flow Water Level hy on on Sxs nt* nt* s Test, Colu (mm MRI Water mn H2O) Colu Inflow mn Inflow 1 Free Free 50 No None None 0 0 — 2 Free Free 55 No None None 1 1 — 3 Free Free 40 No None None 1 0 —4 Free NA NA NA NA NA NA NADied at5.5 months , unrelate d 5 Free Free 40 No None None 2 0 — 6 Free Free 40 No None None 1 1 — 7 Free Free 45 No None None 0 0 — 8 Free Free 50 No None None 2 0 — 9 Free Free 30 No None None 2 1 — 10 Free Free 50 No None None 1 1 — 11 Free Free 50 No None None 0 0 — 12 Closed NA NA NA NA NA NA NA VAP misplac ed in jugular vein NA = not applicable; Pt = patient; Sxs = symptoms. * Possible scores: −2, −1, 0, 1, 2. Two patients did not reach the endpoints. Patient 4 died from pneumonia just before the 6-month follow-up; the VAP had been patent until at least the 3-month follow-up. Patient 12 (Table 2) was found to experience no clinical effect from the shunt at the 3- month follow-up, and the water column test demonstrated that the device was not patent. Shunt revision was planned; during the reoperation it was observed that the device had not been correctly positioned in the jugular foramen during surgery as intended, but low in the IJV where it was not protected by the fixed structure of the jugular foramen. In the remaining 10 patients, the shunt was patent and working at the 3- and 6-month follow- up evaluations. While all adult types of hydrocephalus patients were eligible for enrolment, the study was conducted during the COVID-19 pandemic, when waiting times for MR venograms and lung scintigraphy were extended significantly. It was not possible to coordinate a fast turnaround of these examinations needed for patients with (for example) sub-arachnoid haemorrhage, which meant that the department could only recruit patients with NPH to conduct the study. ICP pressure measured in the control reservoir via the water column tests was within normal limits in all 10 remaining patients at 3- and 6-month follow-up evaluations showing free flow through the outlet. No sign of over-drainage was observed on follow-up MRI. No thrombus formation or endothelial proliferation was noted in any of the patients on MR or CT venograms. Lung perfusion scintigraphy showed no signs of lung emboli. Apart from the 2 patients mentioned above who were omitted from these final results, in 10 patients the endpoint was achieved, with the outlet remaining patent for at least 6 months. The clinical effect on gait disturbance, dementia, and incontinence showed improvement in general and was re- corded as the secondary endpoint. These data were based on the patients’ and / or relatives’ own observations and the sample size is too small to allow for any comparisons to historical data from the literature. Discussion The study was designed to demonstrate that the investigational device can remain patent when placed in the intracranial venous sinus and that it can function effectively for at least 6 months. This criterion is based on the experience from the initial study in 2002 in which more than half of the shunts became blocked at the end of the outlet in the vein (overgrown by endothelium) within approximately 3 months. Because the general survival curve of shunts decreases exponentially, we opted to double the time frame to demonstrate significant improvement. In addition, 6 months is often used in the literature to determine the general survival rate of standard shunts and is reported to be between 30%6and 50%,5the latter based on specific data for adults and the elderly. The initial study on intracranial venous shunting was led by Børgesen at the University Hospital Copenhagen in 1999 using the first generation of the SinuShunt (CSF- Dynamics A / S). This shunt system worked as expected in the initial trials and resulted in immediate relief of hydrocephalus symptoms and did not cause symptoms of over- drainage. The results on the initial 46 patients were reported in 2004.8Further data collected from the neurosurgical departments participating in the trial (150 total patients) confirmed these observations on the immediate clinical effect of shunting to the intracranial sinus. However, the study at the University Hospital Copenhagen was unable to demonstrate long-term success since after the preliminary clinical results were published, it was found that the majority of outlets had ceased to function after approximately 3 months and had become embedded in endothelium, with the pouch formed obliterating the distal end of the outlet. Explantations revealed an important discovery: There was no evidence of blood clots inside or around the outlet nor was there any sinus obstruction by thrombosis. Similar results of shunting to the sagittal sinus were reported by Baert et al.12in 2018 in which clinical benefit was also observed, but where the devices rapidly became occluded. Likewise, Toma et al.’s13review of 7 case series comprising 265 VS shunts noted that the clinical effect was satisfactory with no cases of thrombosis or occlusion found. While the investigational device is, stated simply, a drainage catheter, the design addresses the challenges of ICP control as well as providing a solution to tackle over- drainage that occurs when too much fluid is drawn out of the ventricles (the siphon effect, described below). Despite antisiphon features being added to many shunt designs, over-drainage is still a common issue and causes a miser- able quality of life for patients who experience it as well as being the cause of malfunction. The device tested builds on the concept of the first generation of the SinuShunt, the functionality of which was based on resistance to outflow. The principal design change since the first generation is the introduction of the nitinol frame at the end of the outlet. In the 20 years that have passed since the first trial was halted, vascular nitinol stents have become widely used in the transverse sinus for treatment of intracranial hypertension. Since the safety of nitinol had thus been established for long-term use in the vasculature, the decision was made to borrow from stent technology and use a stent-like frame to overcome endothelial encasement of the silicone drain found in the initial 2002 study. The resistance of the assembled shunt remains critical to the balance of ICP and over- drainage and is set following the Davson equation10,11: ICP = FŔ Rout + Pss,in which FR is the formation rate of CSF, Routis the resistance to CSF outflow (Rout), and Pssis the pressure in the sagittal sinus. Opening pressure of the one-way valve is 5 cm H2O, and the resistance of the entire system is designed and dimensioned to 10 mm Hg / ml / min. The setting of the flow resistance is based on the Routas measured in healthy patients by Ekstedt14and by Albeck et al.15with normal values ranging from 6 to 12 mm Hg / ml / min. The device is designed to be placed in the jugular foramen to avoid the siphon effect. The siphon effect, or hydrostatic force, is commonly experienced with standard ven- triculoperitoneal and ventriculoatrial shunting due to the height difference between ventricles and the shunt outlet and is extremely difficult to resolve mechanically because the force changes in tandem with the constantly changing position of the patient (sitting / standing / lying down). Placing the outlet in the jugular foramen ensures there is almost no height difference regardless of the individual’s physical position. Different placements have been investigated for the VS shunt outlets in the past,12,16,17but the jugular foramen is particularly well-suited as an outlet site for several additional reasons. Primarily, it is in close proximity to the intracranial cavity while at the same time offering a fixed placement for a centralizing, supporting frame such as the one designed. The effect of the location on ICP is important: Instead of ICP being determined by the shunt itself (e.g., in shunts with adjustable pressure) in combination with a distant drainage site with its own pressure variables (e.g., the peritoneum), the ICP is determined by the pressure in the venous sinus and the built-in flow resistance of the outlet. The jugular foramen is also surrounded by bone, apart from a small part of itsanteromedial wall,18,19and will therefore not collapse; the end of the vein, the jugularbulb, is made of dura mater, a strong fibrous wall. Branches of the vagus and hypoglossal nerves are located in the anteromedial part of the foramen, separated from the vein by a fibrous membrane, a continuation of the dura. The tympanic nerve (Jacobson’s nerve) is also situated in its canal in the medial part of the foramen. As the above-cited nerves are covered by bone or a fibrous membrane, they are protected from the slight mechanical force exerted by the expanded frame, thereby avoiding possible side effects such as hoarseness or dry mouth. The mean diameter of the approximately round IJV in the foramen is 9 mm with a standard deviation of 2.5 mm, and the median is 8.5 mm.20The nitinol frame of the investigational device has an unfolded diameter of 12 mm and is able to adapt to a noncircular form and will thus be in contact with the whole circumference of the wall and able to stay in position on a long-term basis while keeping the outlet centrally placed within the frame. In addition to the advantages, the insertion procedure developed in the current study is intended to be easy to perform. The outlet device is inserted with an introducer sheath via the IJV in the neck using a standard intravascular technique and standard imaging technology (fluoroscopy). In pursuit of the ideal shunt, the method of shunting to the intracranial venous sinus merits serious consideration because it offers several advantages over alternative diversion sites. The drainage of CSF is controlled only by the pressure differences between the ICP and the pressure in the sinus, therefore there is no need for antisiphon devices because the siphon effect is eliminated. Over-drainage will not occur from a change of position between the horizontal and vertical posture. When over-drainage is avoided, so are complications of subdural fluid collections or subdural hematomas. Fluctuations of ICP caused by fluctuations of the peritoneal pressure are avoided. The common complications related to the peritoneal drain, e.g., cyst formation, bowel perforation, peritoneal irritation, and drain dis- placement which will lead to shunt revision are avoided. And long periods of low ICP are avoided. Intracranial venous sinus drainage could also reduce the incidence of normal tension glaucoma. Hamarat et al.21found that the risk of developing normal tension glaucoma after shunting for NPH was over 25%. It is also important to note that the placement of a device in the jugular foramen will not hinder the Starling resistor effect of the collapse of the IJV in the neck (shown by Holmlund et al.22). The IJV collapse maintains ICP when in the upright position.23The IJV collapse is still possible with the device located at the point of the jugular foramen as the collapse takes place below the jugular foramen and therefore its regulating effect on ICP is not affected. One drawback of shunting to the intracranial sinus is that the growth of the cranium in infants and children cannot be compensated through an extended drainage catheter length as it can in ventriculoperitoneal shunting. A device that can accommodate this growth will need to be developed for this group of patients. In summary, the potential exists for mimicking physiological drainage providing the outlet device placed in the intracranial venous sinus does not occlude, and it is possible to manage ICP and imitate the balance between CSF production, reabsorption resistance, and pressure in the receiving compartment by diverting CSF into the same cranial space as normalcy. In so doing, over-drainage due to hydrostatic pressure differences and complications associated with drains and / or drainage sites commonly used with state-of-the art cerebrospinal fluid shunts can be avoided. Conclusions The current study represents the first attempt to place a specially designed outlet device in the jugular foramen for the purposes of diverting CSF while mimicking physi- ological principles. The patency of the outlet at 6 months indicates that a shunt outlet can remain in the vein without occlusion by endothelial hyperproliferation or thrombus formation and that the technological improvements made are effective. Shunting to the intracranial sinus with this device can therefore be considered a realistic future possibility for diversion of CSF with relatively few adaptations to existing practices of shunt surgery, but with significant gains by avoiding the siphon effect and lowering shunt failure rates. References 1. Hodges PW, Gandevia SC. Changes in intra-abdominal pres- sure during postural and respiratory activation of the human diaphragm. J Appl Physiol (1985). 2000;89(3):967-976. 2. Sugerman HJ. Effects of increased intra-abdominal pressure in severe obesity. Surg Clin North Am.2001;81(5):1063-1075, vi. 3. McAllister JP II, Williams MA, Walker ML, et al. An update on research priorities in hydrocephalus: overview of the third National Institutes of Health-sponsored symposium “Op- portunities for Hydrocephalus Research: Pathways to Better Outcomes.” J Neurosurg.2015;123(6):1427-1438. 4. Garegnani L, Franco JVA, Ciapponi A, Garrote V, Vietto V, Portillo Medina SA. Ventriculo-peritoneal shunting devices for hydrocephalus. Cochrane Database Syst Rev.2020;6(6): CD012726. 5. LeHanka A, Piatt J. Readmission and reoperation for hydro- cephalus: a population- based analysis across the spectrum of age. J Neurosurg.2020;134(3):1210-1217. 6. Kofoed Månsson P, Johansson S, Ziebell M, Juhler M. Forty years of shunt surgery at Rigshospitalet, Denmark: a retro- spective study comparing past and present rates and causes of revision and infection. BMJ Open.2017;7(1):e013389. 7. Landspatientregisteret. Landspatientregisteret: Avanceret udtræk. Accessed March 14, 2023. (https: / / www.esundhed. dk / Emner / Operationer-og-diagnoser / Landspatientregisteret- Avanceret-udtraek). 8. Børgesen SE, Pieri A, Cappelen J, Agerlin N, Gjerris F. Shunting to the cranial venous sinus using the SinuShunt. Childs Nerv Syst.2004;20(6):397-404. 9. Hamilos M, Petousis S, Parthenakis F. Interaction between platelets and endothelium: from pathophysiology to new therapeutic options. Cardiovasc Diagn Ther. 2018;8(5):568- 580. 10. Børgesen SE, Gjerris F. Relationships between intracranial pressure, ventricular size, and resistance to CSF outflow. J Neurosurg.1987;67(4):535-539. 11. Lalou AD, Levrini V, Garnett M, et al. Validation of Dav- son’s equation in patients suffering from idiopathic normal pressure hydrocephalus. Acta Neurochir (Wien). 2018;160(5): 1097-1103. 12. Baert EJ, Dewaele F, Vandersteene J, Hallaert G, Kalala JO, Van Roost D. Treating hydrocephalus with retrograde ven- triculosinus shunt: prospective clinical study. World Neuro- surg.2018;118:e34-e42. 13. Toma AK, Tarnaris A, Kitchen ND, Watkins LD. Ventriculo- sinus shunt. Neurosurg Rev.2010;33(2):147-153. 14. Ekstedt J. CSF hydrodynamic studies in man.1. Method of constant pressure CSF infusion. J Neurol Neurosurg Psychia- try.1977;40(2):105-119. 15. Albeck MJ, Børgesen SE, Gjerris F, Schmidt JF, Sørensen PS. Intracranial pressure and cerebrospinal fluid outflow conductance in healthy subjects. J Neurosurg.1991;74(4): 597-600. 16. El-Shafei IL, El-Shafei HI. The retrograde ventriculovenous shunts: the El-Shafei retrograde ventriculojugular and ven- triculosinus shunts. Pediatr Neurosurg. 2010;46(3):160-171. 17. Wen HL. Ventriculo-superior sagittal sinus shunt for hydro- cephalus. Surg Neurol. 1982;17(6):432-434. 18. Das SS, Saluja S, Vasudeva N. Complete morphometric analysis of jugular foramen and its clinical implications. J Craniovertebr Junction Spine.2016;7(4):257-264. 19. Freitas CAF, Santos LRMD, Santos AN, Amaral Neto ABD, Brandão LG. Anatomical study of jugular foramen in the neck. Rev Bras Otorrinolaringol (Engl Ed).2020;86(1):44-48. 20. Lv X, Wu Z. Anatomic variations of internal jugular vein, in- ferior petrosal sinus and its confluence pattern: implications in inferior petrosal sinus catheterization. Interv Neuroradiol.2015;21(6):769-773. 21. Hamarat Y, Bartusis L, Deimantavicius M, et al. Can the treatment of normal-pressure hydrocephalus induce normal- tension glaucoma? A narrative review of a current knowl- edge. Medicina (Kaunas).2021;57(3):234. 22. Holmlund P, Johansson E, Qvarlander S, et al. Human jugular vein collapse in the upright posture: implications for postural intracranial pressure regulation. Fluids Barriers CNS.2017; 14(1):17. 23. Qvarlander S, Sundström N, Malm J, Eklund A. Postural effects on intracranial pressure: modeling and clinical evalu- ation. J Appl Physiol (1985). 2013;115(10):1474-1480.

Claims

Patent claims 1. A cerebrospinal fluid shunt device for shunting cerebrospinal fluid from a cerebrospinal fluid containing space and into a venous system cavity of an individual, wherein the cerebrospinal fluid shunt device comprises: - a tubular inlet comprising an inlet end configured for insertion into a cerebrospinal fluid containing space of the individual, the inlet end having an inlet opening for receiving cerebrospinal fluid, - a tubular outlet comprising an outlet end configured for insertion into a venous system cavity of the individual, the outlet end comprising an outlet opening, wherein the inlet opening is fluidly connected with the outlet opening to allow cerebrospinal fluid to flow from the inlet opening to the outlet opening, - a fixator attached to the outlet end and configured to secure a location of the outlet end in the venous system cavity by exerting a radial outward force onto a wall of the venous system cavity at a deployment location of the outlet end in the venous system cavity, wherein the fixator is configured to be converted from a compacted state of the fixator into an expanded use state of the fixator to secure the outlet end at the deployment location, and wherein the radial force is from about 0.1 Newton to 1.0 Newton in the expanded use state.

2. The cerebrospinal fluid shunt device of claim 1, wherein the fixator is attached to the outlet end at or near the outlet opening.

3. The cerebrospinal fluid shunt device of claim 1 or 2, wherein the fixator is configured to secure the outlet end inside a foramen jugulare of the individual.

4. The cerebrospinal fluid shunt device of any of claims 1 to 3, wherein the fixator is flexible, preferably hyperelastic and / or superelastic.

5. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the fixator is configured, in the expanded use state, to secure the outlet end at the foramen jugulare with the outlet opening oriented in a retrograde orientation with respect to the flow of blood through the vena jugularis.

6. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the fixator in the expanded use state extends from the tubular outlet radially outwards relative to the outlet opening of the tubular outlet.

7. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the fixator, in the expanded use state, extends radially outward from all or part of the tubular outlet.

8. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the fixator is attached to the tubular outlet at one or more attachment locations, at least a proximal attachment location of the one or more attachment locations being displaced from the outlet opening by a displacement distance.

9. The cerebrospinal fluid shunt device of claim 8, wherein the fixator, in the expanded use state, has a longitudinal extent defined between the proximal attachment location and a distal end of the fixator, wherein the longitudinal extent is no smaller, preferably larger, than the displacement distance.

10. The cerebrospinal fluid shunt device of any of claims 8 to 9, wherein the fixator, in the expanded use state, defines a cone shape of increasing radial extent between the proximal attachment location and a distal end of the fixator.

11. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the fixator comprises one or more fixator members, each fixator member being attached to the tubular outlet at least at an attachment location displaced from the outlet opening, and each fixator member being configured, in the expanded use state, to extend radially outward from the tubular outlet and longitudinally from the attachment location of the fixator member towards the outlet opening.

12. The cerebrospinal fluid shunt device of any of the preceding claims, wherein the radial force is from about 0.1 Newton to 0.5 Newton in the expanded use state.

13. The cerebrospinal fluid shunt device of any of claims 1 to 12, wherein the radial force is from about 0.5 Newton to about 1.5 Newton in the compacted state, 14. The cerebrospinal fluid shunt device of any of claims 1 to 13, wherein the fixator in the expanded use state maintains the outlet opening at least in a predeterminedminimum distance from the endothelial wall of the vena jugularis at the foramen jugulare.

15. The cerebrospinal fluid shunt device of any of claims 1 to 14, wherein the fixator is configured to secure the outlet end and the outlet opening at the foramen jugulare by exerting a radial outward force on the wall of the vena jugularis.

16. The cerebrospinal fluid shunt device of any of claims 1 to 15, wherein the fixator is configured to secure the outlet end and the outlet opening at the foramen jugulare by exerting a radial outward force on the boundaries or bone structures defining the foramen jugulare in the individual.

17. The cerebrospinal fluid shunt device of any of claims 1 to 16, wherein the radial force is large enough to keep the fixator in place.

18. The cerebrospinal fluid shunt device of any of claims 1 to 17, wherein the radial force is and essentially evenly distributed along a circumference of the fixator.

19. The cerebrospinal fluid shunt device of any of claims 1 to 18, wherein the radial force is a spring force.

20. The cerebrospinal fluid shunt device of any of claims 1 to 19, wherein the radial force is small enough to prevent the fixator to penetrate the endothelial wall of the venous system at the deployment location.

21. A method of implanting a cerebrospinal fluid shunt, the cerebrospinal fluid shunt comprising at least a tubular inlet and a tubular outlet, wherein the method comprises positioning the cerebrospinal fluid shunt with at least part of an inlet end of the tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, and with at least part of an outlet end of the tubular outlet, the outlet end comprising an outlet opening, at a deployment location at a foramen jugulare of the individual, such that the inlet opening is fluidly connected with the outlet opening so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening.

22. The method according to claim 21, wherein positioning the cerebrospinal fluid shunt comprises:a) inserting at least part of the inlet end into the cerebrospinal fluid containing space of the individual, b) inserting at least part of the outlet end into the foramen jugulare of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening inserted into the foramen jugulare of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening.

23. The method of claim 21 or 22, wherein the individual suffers from elevated intracranial pressure.

24. The method of any of claims 21 to 23, wherein the individual suffers from hydrocephalus.

25. The method of claim 24, wherein the hydrocephalus is normal pressure hydrocephalus.

26. The method of any of claims 21 to 25, wherein the cerebrospinal fluid containing space is a cerebral ventricle.

27. The method of claim 26, wherein the cerebral ventricle is a lateral ventricle.

28. The method of any of claims 21 to 27, wherein the cerebrospinal fluid containing space is a subarachnoid space.

29. The method of any of claims 21 through 28, wherein the inlet end is inserted into the cerebrospinal fluid containing space through a burr hole.

30. The method of any of claims 21 to 29, wherein the individual is a human being.

31. The method of any of claims 21 to 30, wherein the outlet end is positioned in the vena jugularis at a position where the vena jugularis passes through the foramen jugulare.

32. The method of any of claims 21 to 31, wherein the outlet end of the tubular outlet is inserted at an access location into the vena jugularis.

33. The method of claim 32, wherein the outlet end inserted into the vena jugularis is guided in a cranial direction through the vena jugularis to the deployment location at the foramen jugulare.

34. The method of claim 13, wherein the outlet end inserted into the vena jugularis is guided to the junction between the sigmoid sinus and the top of the vena jugularis.

35. The method of any one of claims 21 to 34, wherein the outlet end is secured at the deployment location by a fixator attached to the tubular outlet.

36. The method of claim 35, wherein the fixator is attached to the tubular outlet at or near the outlet end of the tubular outlet.

37. The method of claim 35 or 36, wherein the outlet end is secured by the fixator inside the foramen jugulare.

38. The method of any of claims 35 to 37, wherein the fixator is flexible, preferably hyperelastic and / or superelastic.

39. The method of any of claims 35 to 38, wherein the fixator is converted from a compacted state of the fixator into an expanded use state of the fixator to secure the outlet end at the deployment location.

40. The method of claim 39, wherein the fixator in the expanded use state extends radially outwardly from all or part of the tubular outlet.

41. The method of any of claims 39 to 40, wherein the fixator in the expanded use state secures the outlet end at the foramen jugulare with the outlet opening oriented in a retrograde orientation with respect to the flow of blood through the vena jugularis.

42. The method of any of claims 39 to 41, wherein the fixator in the expanded use state extends from the tubular outlet radially outwards relative to the outlet opening of the tubular outlet.

43. The method of any of claims 39 to 42, wherein the fixator is attached to the tubular outlet at one or more attachment locations, at least a proximal attachment location of the one or more attachment locations being displaced from the outlet opening by a displacement distance.

44. The method of claim 43, wherein the fixator, in the expanded use state, has a longitudinal extent defined between the proximal attachment location and a distal end of the fixator, wherein the longitudinal extent is no smaller, preferably larger, than the displacement distance.

45. The method of any of claims 43 to 44, wherein the fixator, in the expanded use state, defines a cone shape of increasing radial extent between the proximal attachment location and a distal end of the fixator.

46. The method of any of claims 39 to 45, wherein the fixator comprises one or more fixator members, each fixator member being attached to the tubular outlet at least at an attachment location displaced from the outlet opening, and each fixator member being configured, in the expanded use state, to extend radially outward from the tubular outlet and longitudinally from the attachment location of the fixator member towards the outlet opening.

47. The method of any of claims 39 to 46, wherein the fixator, in the expanded use state, secures the outlet end and the outlet opening at the foramen jugulare by exerting a radial outward force on the wall of the vena jugularis.

48. The method of any of claims 39 to 47, wherein the fixator, in the expanded use state, secures the outlet end and the outlet opening at the foramen jugulare by exerting a radial outward force on the boundaries or bone structures defining the foramen jugulare in the individual.

49. The method of any of claims 47 to 48, wherein the radial force is large enough to keep the fixator in place.

50. The method of any of claims 47 to 49, wherein the radial force is and essentially evenly distributed along a circumference of the fixator.

51. The method of any of claims 47 to 50, wherein the radial force is from about 0.1 Newton to 1.0 Newton in the expanded use state.

52. The method of any of claims 39 to 51, wherein the fixator in the expanded use state maintains the outlet opening at least at a predetermined minimum distance from the endothelial wall of the vena jugularis at the foramen jugulare.

53. The method of any of claims 21 to 52, wherein the inlet opening inserted into the cerebrospinal fluid containing space of the individual and the outlet opening inserted into the foramen jugulare of the individual are operably connected by a shunt body, the shunt body being connected at one end of the shunt body to the tubular inlet, and connected at another end of the shunt body to the tubular outlet.

54. The method of claim 53, comprising placing the shunt body subcutaneously.

55. The method of any of claims 53 to 54, wherein the connection between the shunt body and the tubular outlet is placed subcutaneously.

56. A method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in a foramen jugulare of an individual, said cerebrospinal fluid shunt comprising at least a tubular inlet and a tubular outlet, the method comprising the step of positioning the cerebrospinal fluid shunt with at least part of an inlet end of the tubular inlet, the inlet end comprising an inlet opening, in a cerebrospinal fluid containing space of the individual, and with at least at least part of an outlet end of the tubular outlet, the outlet end comprising an outlet opening, in the foramen jugulare of the individual, such that the inlet opening is fluidly connected with the outlet opening so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening.

57. A method of shunting cerebrospinal fluid from a cerebrospinal fluid containing space of an individual to a foramen jugulare of the individual, said method comprising the steps of i) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, ii) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the foramen jugulare of the individual, and iii) shunting cerebrospinal fluid from the cerebrospinal fluid containing space of the individual to the foramen jugulare of the individual.

58. A method of inserting a cerebrospinal fluid shunt in a cerebrospinal fluid containing space and in a foramen jugulare of an individual, said method comprising the steps of a) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebrospinal fluid containing space of the individual, b) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into a foramen jugulare of the individual, and c) operably connecting the inlet opening inserted into the cerebrospinal fluid containing space of the individual with the outlet opening inserted into the foramen jugulare of the individual so that cerebrospinal fluid is able to flow from the inlet opening to the outlet opening.

59. The method according to claim 58, wherein the method, in particular the inserting at least part of the outlet end, comprises the further steps of d) guiding the outlet end of the tubular outlet, the outlet end comprising the outlet opening, through the vena jugularis towards the foramen jugulare, and e) locating the tubular outlet end in a cavity of the foramen jugulare.

60. A method of shunting cerebrospinal fluid from a cerebral ventricle of an individual to the vena transversa or the sigmoid sinus of the individual, said method comprising the steps of i) inserting at least part of an inlet end of a tubular inlet, the inlet end comprising an inlet opening, into a cerebral ventricle of the individual, ii) inserting at least part of an outlet end of a tubular outlet, the outlet end comprising an outlet opening, into the vena transversa of the individual, the tubular outlet having an expandable fixator attached to it at or near the outlet end, iii) converting the fixator from a compacted state into an expanded use state when the at least part of the outlet end is positioned at a deployment site inside the vena transversa or the sigmoid sinus, andiv) shunting cerebrospinal fluid from the cerebral ventricle of the individual to the vena transversa or the sigmoid sinus of the individual.

61. The method according to any one of claims 21 through 60, wherein the shunt device is the shunt device according to any one of claims 1 through 20.

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