Treatment for hydrocephalus

Abstract

To provide a shunt system used to treat excess cerebrospinal fluid (CSF) accumulation.SOLUTION: In some embodiments, a system includes a cleaning mechanism designed to clean a portion of a shunting system. A ventricular catheter used in a CSF draining shunt system includes slits to facilitate CSF drainage, and biodegradable or bioresorbable material along one or more of these slits. A locking mechanism facilitating secure fitting between a catheter tubing and a shunt valve element is described. A mechanical valve to regulate CSF flow within a valve housing between a CSF inlet and a CSF outlet is described.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (Related Applications) This application claims priority to U.S. Provisional Application No. 62 / 666,636, filed May 3, 2018, entitled Treatment of Hydrocephalus and Ventriculoperitoneal Shunts, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Cerebrospinal fluid (CSF) is a fluid found in the brain and spinal cord. It is produced in the choroid plexus of the ventricles and serves several purposes, including acting as a buffer for the brain, transporting nutrients and removing waste products from the brain, and regulating changes in pressure within the brain. When CSF production exceeds absorption, pressure increases and CSF volume increases, which can lead to hydrocephalus, a swelling of the brain due to CSF ​​accumulation. Hydrocephalus can lead to problems such as balance and vision problems, increased head size, intracerebral hemorrhage, cerebral edema, impaired brain function, and brain herniation.

[0003] One treatment for hydrocephalus, known as a shunt, involves transferring cerebrospinal fluid from the brain to other parts of the body, such as the abdomen, lungs, or heart. One well-known delivery area is the peritoneal cavity within the abdomen, and delivery from the ventricles to the peritoneal cavity is known as a ventriculoperitoneal shunt (VP shunt). This shunt system uses a ventricular catheter in the brain to collect and deliver CSF, a second drainage catheter to deliver CSF to another part of the body (e.g., the peritoneal cavity), and a valve between them to regulate the flow of CSF from the brain to the drainage site.

[0004] There are several problems associated with shunts. First, CSF can clog the catheter over time, a problem exacerbated by ventricular catheters, which are frequently exposed to CSF. This clogging reduces the effectiveness of the shunt and necessitates replacement over time. Second, it can be difficult to precisely calibrate the valve to drain the appropriate amount of CSF from the brain. That is, draining too much CSF reduces available CSF, while draining too little fails to address the hydrocephalus problem. Furthermore, the typical mechanical valves that regulate CSF flow to the drainage system have a high rate of failure for a variety of reasons.

[0005] There is a need for shunt devices and systems that address these issues. Summary of the Invention

[0006] The present invention relates to devices, systems, and methods designed to address problems associated with shunt procedures.

[0007] In some embodiments, the shunt system includes a flushing mechanism designed to flush CSF residue from within the ventricular catheter of the broader shunt system. In one embodiment, the flushing mechanism includes a spring plunging element used to flush the slit through which CSF can pass. In one embodiment, the flushing mechanism includes a flushing piston element used to flush the slit through which CSF can pass. In one embodiment, the flushing mechanism includes a rotating element used to flush the slit through which CSF can pass.

[0008] In one embodiment, a ventricular catheter used in a CSF drainage shunt system includes slits to facilitate CSF drainage and a biodegradable or bioabsorbable material along one or more of the slits.

[0009] In one embodiment, a locking mechanism is described that facilitates a secure fit between the catheter tube and the shunt valve element.

[0010] In one embodiment, a mechanical valve utilizing a weighted or thinned disc is described that regulates the flow of CSF within a valve housing between a CSF inlet and a CSF outlet.

[0011] In one embodiment, the hydrogel is used to seal the pore opening used as vascular access during a CSF shunt procedure.

[0012] In one embodiment, an electrical system used to monitor and / or communicate patient data related to a CSF shunt system is described.

[0013] In one embodiment, the shunt system includes a mechanical, electromechanical, and / or electrical mechanism for selectively regulating the flow of CSF. [Brief explanation of the drawings]

[0014] These and other aspects, features and advantages of which embodiments of the present invention are possible will become apparent and elucidated from the following description of embodiments of the invention, which proceeds with reference to the accompanying drawings.

[0015] [Figure 1] FIG. 1 shows a shunt system.

[0016] [Figure 2] FIG. 2 shows a ventricular catheter with multiple slits to allow CSF inflow.

[0017] [Figure 3] FIG. 3 illustrates a spring plunger flushing mechanism in an extended configuration for use with a ventricular catheter, according to one embodiment.

[0018] [Figure 4] FIG. 4 illustrates a spring plunger flushing mechanism in a retracted configuration for use with a ventricular catheter, according to one embodiment.

[0019] [Figure 5] FIG. 5 shows a close-up view of the spring plunger flushing mechanism of FIG. 3 in an extended configuration.

[0020] [Figure 6] FIG. 6 shows a close-up view of the spring plunger flushing mechanism of FIG. 4 in a retracted configuration.

[0021] [Figure 7] FIG. 7 shows a stationary piece of a spring plunger cleaning mechanism, according to one embodiment.

[0022] [Figure 8] FIG. 8 shows the moving piece of the spring plunger cleaning mechanism, according to one embodiment.

[0023] [Figure 9] FIG. 9 shows the inner lumen of the moving piece of the spring plunger flushing mechanism, according to one embodiment.

[0024] [Figure 10] FIG. 10 shows the inner lumen of the moving piece of the spring plunger flushing mechanism, according to one embodiment.

[0025] [Figure 11] FIG. 11 illustrates a ventricular catheter that utilizes multiple small CSF entry slits that can be used with an irrigation mechanism, according to one embodiment.

[0026] [Figure 12] FIG. 12 shows a cleaning mechanism utilizing a spring and piston in an extended configuration, according to one embodiment.

[0027] [Figure 13] FIG. 13 shows a cleaning mechanism utilizing a spring and piston in a retracted configuration, according to one embodiment.

[0028] [Figure 14]FIG. 14 illustrates a ventricular catheter that utilizes multiple small slits that can be used with a flushing mechanism, according to one embodiment.

[0029] [Figure 15] FIG. 15 shows the shunt valve interface.

[0030] [Figure 16] FIG. 16 shows a locking mechanism for a shunt valve interface, according to one embodiment.

[0031] [Figure 17] FIG. 17 illustrates a shunt valve system, according to one embodiment.

[0032] [Figure 18] FIG. 18 shows a valve used in the shunt valve system of FIG. 17, according to one embodiment.

[0033] [Figure 19] FIG. 19 shows a top disk used in a valve, according to one embodiment.

[0034] [Figure 20] FIG. 20 shows a bottom disk used in a valve, according to one embodiment.

[0035] [Figure 21] FIG. 21 shows a flow chart for a telecommunications system used as part of a shunt system, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0036] Specific embodiments of the present invention will now be described with reference to the drawings. However, the present invention can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. The terminology used in the detailed description of the embodiments shown in the accompanying drawings is not intended to be limiting of the present invention. In the drawings, like numbers refer to like elements.

[0037] Excessive CSF production and accumulation, which can lead to hydrocephalus and related conditions, was highlighted in the Background section above. Shunts are one technique used to address hydrocephalus and excess CSF. This technique involves using a catheter to drain cerebrospinal fluid (CSF) from the brain, another catheter to carry the CSF to another blood vessel, and a valve between the two catheters to regulate the flow of CSF between the two catheters. This valve ensures that an adequate amount of CSF is drained from the brain. If too much CSF is drained, adverse effects occur because not enough CSF is available to perform its essential functions, such as acting as a buffer for the brain, transporting nutrients and removing waste products from the brain, and regulating changes in pressure within the brain. If too little CSF is drained, the patient will still have to deal with problems caused by excess CSF, including hydrocephalus.

[0038] Shunt systems can deliver CSF to various areas of the body, such as the lungs, heart, or other areas of the brain. VP shunts are a well-known shunt technique that involve delivering CSF to the peritoneal cavity within the abdomen. While the shunt systems, devices, techniques, and methods described in embodiments of the invention herein are often described by us as VP shunts (i.e., shunt systems that deliver CSF to the abdomen), they can also be used in shunt systems that deliver CSF to other locations in the body / vasculature.

[0039] FIG. 1 shows a schematic of a VP shunt system 100. The shunt functions to move CSF from the brain 102 to the peritoneal cavity 110. The shunt system includes a ventricular catheter 104 that collects, i.e., collects, the CSF in the ventricles and transfers it from the ventricles 102. The system further includes a second outlet, i.e., a drainage catheter 108 that directs the collected CSF into the abdominal cavity 110. Between the two catheters 104, 108 is a valve 106 that regulates the flow rate between the two catheters. The purpose of the valve is to regulate the amount of CSF transported from the brain (via the ventricular catheter 104) to the abdomen (via the drainage catheter 108). The valve 106 can include any of a number of mechanical or electrical valve mechanisms commonly known in the art to regulate flow.

[0040] Shunt failure rates are relatively high. It is estimated that 18,000 to 33,000 shunts are placed in the United States each year. Up to one-third of these failures occur in the first year, and up to 50% in the first two years. There are numerous causes for failure, including mechanical failure of the flow valve that drains CSF and the accumulation of material within the catheter, which causes blockage. CSF often contains proteins and calcium, which can accumulate within the catheter and lead to blockage of the catheter drainage system. This problem is more pronounced with ventricular catheters, which provide a gateway for brain CSF to enter the shunt system and thus expose it to greater amounts of CSF. Over time, the catheter fills with more accumulated material, reducing the shunt's effectiveness at delivering CSF. Therefore, over time, implantation of a new ventricular catheter or an entirely new shunt system is required.

[0041] The ventricular catheter 104 is shown in more detail in FIG. 2. The ventricular catheter 104 typically includes multiple holes or slits 114 spaced along the catheter's end section (i.e., the portion of the ventricular catheter 104 furthest from the valve 106 and exposed to CSF ​​within the ventricle). These holes or slits 114 serve as access conduits for CSF to enter the ventricular catheter 104. Multiple spaced holes / slits are preferred so that there are sufficient entry points for CSF to enter the catheter, thereby maximizing drainage capacity. While four holes / slits 114 are shown in FIG. 2, this is merely exemplary, and fewer or more holes may be used, including those located along various portions of the ventricular catheter 104. These holes or slits 114 are often locations where accumulated material from the CSF (e.g., protein or calcium deposits) tends to accumulate. As material accumulates in these entry ports, the amount of CSF available to enter the ventricular catheter is reduced, thereby inhibiting the shunt system's ability to effectively drain CSF. The following invention embodiments address this problem by providing various mechanisms that can be used to flush these slits or holes.

[0042] 3-4 illustrate one embodiment of a flushing mechanism 120 used to flush the CSF inlet slit 114 of the ventricular catheter 104. The mechanism 120 is constructed on a section of the ventricular catheter 104 and is positioned over the CSF inlet port 114. The flushing mechanism 120 flushes the inlet slit 114 using a reciprocating motion approach, with the mechanism having a first extended position that covers the slit and a second retracted position that exposes the slit. In one embodiment, one mechanism 120 is used for each slit in the ventricular catheter. In one embodiment, each mechanism 120 covers multiple slits so that each flushing mechanism 120 flushes multiple slits. In one embodiment, the flushing mechanism 120 utilizes a spring plunger as the basis for its reciprocating motion (shown in more detail in FIGS. 5-6). The flushing mechanism 120 utilizes a spring plunger system including a fixed base piece 122 and a movable reciprocating piece 132. The fixed base piece 122 has a platform 124 to which one or more springs 126 are connected. One end of one or more springs 126 is connected to the platform 124, and the other end of the one or more springs 126 is connected to the movable reciprocating piece 132. The reciprocating piece is hollow, in that it is not completely solid; preferably, it uses a thin outer wall and a thin inner wall, with the spring disposed between these two wall sections. In this manner, the spring 126 can be coupled to the reciprocating piece 132. The base piece 122 and the reciprocating piece 126 each include a lumen, which is necessary to allow the entire flushing mechanism 120 to slide over the ventricular catheter; therefore, the lumen of the base piece 122 and the lumen of the reciprocating piece 132 will be larger than the outer diameter of the ventricular catheter 104. These lumens are shown in more detail in FIGS. 7-8, where the fixed piece 122 includes a lumen 122a that is larger than the outer diameter of the ventricular catheter, and the movable piece 132 also includes a lumen 132a that is larger than the outer diameter of the ventricular catheter.

[0043] While one or more springs 126 are contemplated, in one embodiment, multiple springs 126 are used, equally spaced circumferentially along the inner portion of the movable piece 132. When the spring 126 is fully extended, the reciprocating piece is positioned furthest relative to the base piece, as shown in Figures 3 and 5. This corresponds to the reciprocating piece 132 covering the associated slit 114. When the spring 126 is fully compressed, the reciprocating piece contracts relative to the base piece, as shown in Figures 4 and 6. This corresponds to the reciprocating piece 132 exposing the associated slit 114, thereby allowing CSF to more easily enter the associated slit / hole 114.

[0044] The base piece 122 and the movable piece 132 are shown in more detail in Figures 7-8. Figure 7 shows the base piece 122, which includes a lumen 122a that allows the base piece to be mounted onto a ventricular catheter. Thus, the lumen 122a should be sized larger than the ventricular catheter so that the base piece can be positioned over the ventricular catheter, as described above. The fixed / base piece 122 also includes a platform 124, to which one or more springs 126 are attached, as described above.

[0045] FIG. 8 shows the movable / reciprocating piece 132 in more detail. The movable piece 132 is movable relative to both the ventricular catheter 104 and the fixed piece 122. The movable piece 132 can be disposed on the ventricular catheter and, as such, includes its own lumen 132a, which is larger in size than the ventricular catheter, as described above. This lumen 132a is preferably larger in size than the fixed piece 132 so that, when the spring is compressed, the movable piece 132 can slide over the fixed piece 122, as shown in FIGS. 4 and 6. The movable piece 132 is hollow in that it has a first outer wall defining the outer periphery of the movable piece 132, a second wall defining the lumen 132a, and an open space therebetween. The spring 126 is mounted within the movable piece 132, spanning this open-space passage section. The other end of the spring 126 is attached to the platform section of the fixed base piece 122, as described above. While the base piece 122 is mechanically fixed to the surface of the ventricular catheter (e.g., via a connecting medium such as adhesive, welding, or other means between the base piece lumen 122a and the underlying ventricular catheter), the movable piece 132 is not fixed and thus reciprocates, assuming the positions shown in Figures 5-6 as the spring 126 contracts and expands. Because the lumen 132a of the movable piece 132 is larger than the width or diameter of the fixed piece 122, the movable piece 132 overlaps the fixed piece 122 when the spring contracts, as shown in Figures 4 and 6.

[0046] One or more springs 126 connecting the base piece 126 to the reciprocating / moving piece 132 compress and expand according to the pressure in the area, which changes based on the blood flow caused by the pumping of the heart. Thus, there should be a relatively consistent cycle of expansion and compression that follows the heartbeat and the resulting natural flow of blood through the vasculature. In this aspect, no battery, motor, or other external driver is required to control the position of the moving piece 132, although in certain embodiments, these additional elements may be used to electromechanically control the position of the moving piece 132.

[0047] The mechanism used to clean the slit 114 as the movable piece 132 passes over it can be accomplished in a number of ways. In one embodiment, the wall forming the perimeter of the lumen 132a can include one or more protruding structures that protrude radially inward into the lumen 132a. In this manner, the protruding structures lightly touch or physically penetrate a portion of the slit 114 as the movable piece 132 passes over it, thereby cleaning the slit. In another embodiment, the wall can include a roughened or abrasive surface that protrudes slightly into the lumen 132a and lightly touches or protrudes slightly into the slit as the movable piece passes over it. In another embodiment, one or more brushes protruding from the lumen 132a are utilized. These configurations are illustrated in FIGS. 9-10, where protruding elements (e.g., rods), roughened / abrasive elements, or brush-like elements 134 are shown extending from the interior of the lumen 134 of the movable piece 132. These cleaning elements 132, 134 may extend directly from the wall of the lumen 132a or may extend from the interior of the movable piece 132 and penetrate into the lumen 132a.

[0048] Because the lumen 132a of the movable piece 132 is larger than the fixed piece 122 (to facilitate movement on the fixed piece 122, as discussed above), the protrusions or roughened surface must be especially long in order to contact the holes in the ventricular catheter. One way to alleviate this is to include another, smaller, internal secondary lumen on the movable piece 132 that also functions to fit over the ventricular catheter. By including a smaller secondary lumen, the gap between the ventricular catheter is minimized, and the inclusion of protrusions or roughened areas utilized in this smaller secondary lumen means that the protrusions / roughened sections can be smaller while still being able to contact and clean the holes or slits.

[0049] In one embodiment, as shown in Figures 9-10, the slits are located on only one side of the catheter, and the lumen has protrusions, abrasives, brushes, or cleaning surfaces 134 located on only one side of the lumen. In another embodiment, the slits are located along opposing sides of the catheter. Cleaning surfaces can then be positioned along both sides of the lumen to clean the slits on both ends. In one embodiment, the cleaning surfaces of lumen 132a of movable piece 132 are spaced radially and / or longitudinally throughout all or part of lumen 132a (and thus located in various regions of lumen 132a).

[0050] In one embodiment, multiple slits 114 are used along the ventricular catheter 104, and some or all of these slits are configured so that each slit utilizes its own individual flushing mechanism 120 (as shown in FIG. 4). In one embodiment, multiple flushing mechanisms 120 are used, and the movable segments 132 are connected to one another (e.g., via springs). In this manner, the movement of some or all of the movable segments 132 on the different flushing mechanisms 120 can be coordinated, so that the movable segments 132 extend in unison and retract in unison (rather than relying solely on the pulsatile nature of blood flow). In embodiments where an external electromechanical driver is used to drive the movement of the movable segments 132, these cycles can be coordinated via a common driver or via multiple drivers that are synchronized with each other.

[0051] In one embodiment (shown in FIG. 11 ), the ventricular catheter 104 may use multiple small slits 114 rather than using a large slit 144 such that a single flushing mechanism can be used for each slit. In this embodiment, a single spring plunger flushing mechanism 120, such as those shown above in FIGS. 3-10 , can be utilized to flush multiple of these slits. For example, one flushing mechanism 120 spans the multiple slits shown in FIG. 11 . Multiple flushing surfaces 134 of the lumen 132 a of the movable piece 130 are used to flush the multiple smaller slits 144. In this manner, one flushing mechanism 120 can be used for multiple (or all) of the slits 144. In another embodiment, the slits are spaced apart in different segments on the ventricular catheter, with each segment utilizing its own flushing mechanism 120 to flush the multiple slits within that particular catheter segment. The moving pieces can be optionally linked as described above so that they move in unison, or no linkage is used and blood pulsatility controls the movement of the moving pieces (which should generally result in a relatively consistent movement pattern across all moving pieces).

[0052] Another embodiment of the flushing mechanism is shown in FIGS. 12-13. This embodiment utilizes a housing 140 that overlaps the end section of the ventricular catheter 104 (e.g., the section of the ventricular catheter containing the CSF inlet hole or slit 114). The interior of the housing 140, as shown in FIGS. 12-13, includes a piston flushing element 146 having a thickened end region 148 and a spring 150 connected to the piston so that the piston can reciprocate between proximal and distal configurations. The spring expands and contracts based on various variables. In one example, as CSF accumulates within the housing, the CSF exerts pressure on the piston 146 and the connected spring 150. As this pressure increases, the spring compresses, retracting the attached piston and partially exposing the holes 114 in the ventricular catheter, allowing CSF to enter the ventricular catheter 104 through these holes 114. In this manner, CSF enters the ventricular catheter in a controlled manner depending on the amount of CSF accumulated in or near the ventricular catheter housing section 140. The piston has a slightly larger lumen than the ventricular catheter end section, and thus the piston 146 (as well as the housing 140 and spring 150) is positioned around the ventricular catheter. The lumen utilizes various protrusions, brushes, or roughened surfaces as shown in FIGS. 3-10 (particularly highlighted in FIGS. 9-10 and associated element 134) and discussed above with respect to the discussed embodiment. These cleaning elements 134 clean the bore 114 as the piston moves back and forth over it. A thickened end region 148 of the piston lightly contacts the housing and functions to clean the interior surface of the housing from CSF accumulation. This end region 148 may include similar protrusions, brushes, or abrasive surfaces to help clean or scrape buildup from the interior of the housing 140. This housing element 140 is preferably positioned in the distal section of the ventricular catheter where CSF accumulates in the neurovasculature; in one example, this distal catheter section is located within the cerebellopontine angle cistern of the neurovasculature.

[0053] One advantage of the irrigation interface of Figures 12-13 is that as CSF accumulates, it exerts pressure on the piston 146 and spring 150, thereby metering CSF drainage. As this pressure increases, it pushes the piston and spring toward the configuration of Figure 13, exposing more holes 114 as the pressure increases, thereby increasing CSF drainage as the pressure increases. Overdrainage of CSF is problematic because the brain requires a certain amount of CSF to cushion the brain and facilitate proper nutrient absorption. Underdraining CSF drainage is not good because excessive CSF builds up, causing increased pressure in the brain and hydrocephalus. In this embodiment, CSF drainage is controlled based on the accumulated pressure exerted by the CSF, so some CSF will accumulate, but excess CSF will drain as pressure builds up at the piston / spring interface. In some examples, the spring tension and piston weight can be customized to precisely control the amount of CSF drainage allowed. In some embodiments, an electronically integrated system is utilized in which the spring tension is mechanically customized and varied based on passive measurements made by an integrated electrical measurement system, thereby customizing the proper ejection based on the measurement system measuring the CSF pressure (the pressure with which the CSF is acting on the piston 148 and / or spring 150).

[0054] In another embodiment similar to the concept of FIGS. 12-13, a rotating element is connected to a mechanical rod within the housing 140, and the rotating element circumferentially ...

[0055] Other embodiments of the present invention can address the problem of CSF and associated material accumulation along the fluid entry point of the ventricular catheter by utilizing specific coatings on the ventricular catheter surface in the section of the ventricular catheter containing the CSF entry hole 114. These coatings can be used in conjunction with the flushing mechanism concepts described above or as a standalone solution. For example, the ventricular catheter or entry hole 114 can be coated with a plasma protein adsorption inhibitor, such as, but not limited to, poly(2-methoxyethyl acrylate) (PEMA or X-coat). Additionally, antimicrobial coatings can be used to prevent infection. The entry hole 114 and catheter lumen can also be customized to help prevent clogging and blockage due to CSF ​​accumulation; for example, larger entry holes and larger lumens can be used to prevent blockage. Additionally, these coatings can be used on the inner walls of the ventricular catheter 104 to prevent material accumulation within the catheter itself.

[0056] Other embodiments can utilize a biodegradable or bioabsorbable material to cover the CSF entry holes 114, allowing the material to degrade or resorb over different periods of time, revealing the holes. The idea is that some holes without this material will become clogged with CSF over time, while other holes with a degradable or resorbable covering material (which will fade or degrade over time) will open, allowing CSF to drain through these other holes. The ventricular catheter is manufactured with additional holes or slits 114. Some of the holes are then covered with a thin film of a biodegradable or bioabsorbable material, such as, but not limited to, polyalphahydroxy acid and / or polyesteramide (PEA), which takes a certain amount of time to absorb. Materials with multiple / different absorption rates can be used to cover the various holes. This difference in absorption rate can be due to thick or thin covering materials or the use of various materials with different absorption rates. Additionally, a coating layer can be applied over the catheter (and / or a flow control valve connected to the ventricular catheter selectively allows CSF to drain from the drainage catheter into the abdomen) to further prevent protein adsorption. Figure 14 shows an example of a multiple resorption approach, where pores 114a are fully open (meaning uncoated), making them the first pores through which CSF can enter (though they may close over time). Pores 114b, for example, utilize a membrane that absorbs after 12-24 months. That is, these pores fully open after 12-24 months and serve as part of the clogged pore 114a. Pores 114c can then utilize a membrane coating that absorbs over approximately 3-4 years, which serves as part of the clogged pores 114a-114b. This pattern can continue for various pore segments along the length of the ventricular catheter 104. These pores with different absorption rates can also be spaced at different locations along the catheter to create a more randomized profile. In this way, clogging of a particular foramen opens other foramen, reducing the likelihood of multiple or multiple foramen becoming clogged simultaneously, which could reduce the efficiency of CSF drainage.This approach reduces the likelihood of having to implant a new ventricular catheter, or at least increases the time interval over which this procedure must be performed. Another advantage of this approach is that it maintains a calibrated CSF drainage protocol. While some foramina become blocked over time, thereby reducing CSF inflow / outflow capacity, other foramina open, thereby roughly balancing the total number of foramina / slits available at any given time for CSF drainage.

[0057] The coating can be applied in a variety of locations, including, for example, along the slit / hole / opening 114 of the ventricular catheter, as described above. In one embodiment, the coating protrudes outward from the hole. In one embodiment, the coating is applied so that it protrudes radially inward from the hole. In one embodiment, the coating is flush with the plane of the hole itself. The coating can be applied in a variety of ways, such as by a mechanical (manual) coating process or by machine. In one embodiment, the entire catheter (or a portion of the catheter) itself is immersed in the coating solution, and the coating is applied evenly to the immersed section of the catheter. In some embodiments, drainage catheters also utilize coatings to prevent the accumulation of bacteria or material. In some embodiments, the coating is utilized along the section of the catheter directly adjacent to the valve to prevent material accumulation from interfering with the mechanical valve device.

[0058] In addition to ventricular catheter blockage, another problem with shunt procedures is ensuring that the ventricular catheter (which directs CSF from the neurovasculature to the shunt valve device) and the drainage catheter (which directs CSF from the shunt valve device to a drainage site, such as the peritoneal cavity) remain connected to the valve device. If either of these catheters becomes dislodged or loose, the shunt's ability to effectively collect and direct CSF from the brain is limited. The following embodiments address this problem by providing a locking mechanism that allows for a better connection between the shunt valve and the connected catheters.

[0059] FIG. 15 illustrates a typical shunt connection interface. The typical system includes a shunt housing / valve 200 containing a valve element for selectively measuring CSF. Additionally, first 202 and second 204 connection interfaces / fittings connect to a ventricular catheter (whose first end is in the CSF accumulation area of ​​the brain and whose second end is attached to the connection interface 202) and a drainage catheter (whose first end is attached to the connection interface 204 and whose second end has a path to a drainage area, such as the abdomen), respectively. Typical interfaces include raised portions 202a and 204a onto which the catheter rests, allowing for a snug connection between the catheter and the shunt valve. However, this section does not necessarily secure the catheter, and the catheter can often be separated from the fittings and connection interface.

[0060] FIG. 16 illustrates an embodiment of a mating interface or fitting 206 (which may represent one or both of the two fittings 202, 204, which are at either end of the shunt valve housing 200) that utilizes multiple connecting elements 206a. These elements may be female recesses or indentations extending into the surface of the fitting 206, male protrusions extending outward from the surface of the fitting 206, or a combination of the two. The end section of the catheter, particularly the section of the catheter disposed on the fitting, includes a corresponding interface (e.g., a protrusion that fits into a recess in the fitting 206, a recess that fits into a protrusion in the fitting 206, etc.) such that the catheter and fitting are coupled by a fit between their respective interfaces. Some or all of the connecting elements 206a may be used, whereby the catheter may utilize its own corresponding fitting interface that couples with some or all of the connecting elements 206a. In one example, the connecting elements 206a shown in black in FIG. 16 can be thought of as protrusions extending outward from the fitting 206, and the connecting elements 206a shown in white can be thought of as recesses recessed inward from the fitting 206. A corresponding interface surface on the end of the connecting catheter then has a corresponding surface that engages this area (e.g., a recessed or female area to mate with the protrusions 206a shown in black, and a male protrusion to mate with the female recesses 206a shown in white). Not all connecting elements 206a need to be engaged. For example, a portion of the connecting elements 206a is actually used to couple the fitting to the catheter thereon. In one embodiment, only protrusion sections or only recess sections are used. For example, the fitting interface 206a utilizes only female recessed structures, and the catheter interface includes only male convex structures. Alternatively, the fitting interface 206a is only male convex structures, and the catheter interface includes only female concave structures.

[0061] Typical shunt valves utilize a one-way valve design that includes a ruby ​​ball that presses against a spring. When a certain pressure is reached, the valve opens, allowing CSF to enter the drainage catheter through the valve outlet segment. Sometimes, a magnet is additionally used to optimize the desired CSF flow rate for each patient. However, due to the large number of mechanical parts, mechanical failure of the valve components is common. The following embodiments describe a valve concept that utilizes fewer mechanical parts to address this valve failure issue.

[0062] The shunt valve housing 200 is shown in Figure 17 and includes an inlet end 202 that connects to a ventricular catheter to collect CSF and an outlet end 204 that connects to a drainage catheter to drain the CSF. In the situation shown in Figure 17, CSF flows from left to right. The valve housing 200 includes a pre-chamber 208 and a valve chamber 209 that houses a valve 210, and the CSF flows first into the pre-chamber 208 and then into the valve chamber 209. The valve chamber 209 includes a top section 209a and a bottom section 209b and a valve 210 that regulates the flow rate between them.

[0063] Valve 210, shown in more detail in FIG. 18, includes a stem 214 and a protruding anchor 212, which is secured to the top section of valve chamber 209 via a hole. Around the periphery of the anchor is an inlet hole 211 that allows CSF inflow, as shown in FIG. 17. Valve 210 includes a top disk 216 and a bottom disk 218. Both disks, shown in more detail in FIGS. 19-20, each include an intermediate hole that allows passage of valve stem 214, which couples the two disks together. Mechanical valve operation, the opening and closing of valve 210, will now be described in more detail.

[0064] Valve 210, as described above, includes top disk 216 and bottom disk 218. Top disk 216 includes a plurality of holes 220 that are aligned with inlet holes 211 in valve chamber 209. When CSF enters valve chamber 209, it flows through inlet holes 211 and into holes 220 in top disk 216. Bottom disk 218 does not include such a plurality of holes and is weighted such that portions of bottom disk 218 (e.g., the right side of the disk, which is opposite outlet 204) are lighter than other portions (e.g., the left side). This differential weighting can be achieved in a number of ways, including, for example, by using a lighter material in the lighter portions of bottom disk 218 or by making portions of the bottom disk thinner. The weight and pressure of the CSF increases as it accumulates in the top section of the valve chamber 209 and enters the holes in the top disk 216, increasing its weight, which eventually causes the lighter section of the bottom disk 218 to pivot and allow the CSF to exit. This pivoting action means that the stem section 214 is slightly longer than the bottom disk or is not directly fixed to the bottom disk 218, which has some elasticity and moves slightly as the CSF weight increases.

[0065] When sufficient CSF accumulates, the heavier or thicker left side of the bottom disc also pivots, allowing CSF to exit through the bottom chamber of the valve chamber 209. In this embodiment, when the CSF threshold weight is not exceeded, the valve 210 is in a closed state, in which the top and bottom discs fit together tightly so that CSF cannot exit the valve. Next, the valve 210 is in a partially open state, in which the thinner or lighter portion of the bottom disc 218 (e.g., the disc section closer to the outlet end 204 of the shunt valve system) opens to partially allow CSF to exit. Finally, the valve 210 is in a fully open state, in which the entire bottom disc 208 opens or pivots relative to the top disc, allowing maximum CSF egress.

[0066] In one embodiment, the disks 216, 218 of the valve 210 are both made of silicone and are approximately 0.3 inches in diameter. The top disk 216 is approximately 0.07 inches thick and contains six to eight holes 220 around its periphery. The bottom disk 218, as described above, decreases in thickness as you move around the disk, with the thickest section being approximately 0.07 inches and the thinnest section being approximately 0.02 inches. While the above description specifically describes the portion of the bottom disk 218 facing the outlet 204 as being the thinnest, in practice it does not necessarily matter which section of the bottom disk 218 is thinner, because CSF will likely accumulate in the bottom chamber 209b of the valve chamber 209 and be pushed through the outlet 204 when the bottom chamber is filled with CSF. Therefore, as long as any portion of the bottom disk 219 is thinner (or lighter), it will allow CSF to be expelled from the top section of the valve chamber 209 when a threshold weight or pressure is reached. This design therefore forms a pressure gradient one-way valve, with the two-disc interface preventing backflow of CSF.

[0067] The purpose of the prechamber 208 is to accumulate CSF before it enters the valve chamber 209. However, in some embodiments, the prechamber 208 can also be used for subcutaneous sampling of CSF and / or to test for proper valve function. The prechamber can be compressed or palpated / shaken for testing purposes. For example, the valve flow can be configured so that there is not enough fluid in the prechamber to completely fill it, but a certain amount of fluid is always present in the prechamber. If the prechamber bubble cannot be pushed down, the prechamber will be completely filled, indicating distal catheter occlusion. On the other hand, if the prechamber bubble continues to descend after pressurization, this would indicate proximal catheter occlusion; therefore, prechamber material properties can be configured to act as an indicator of proper functionality of ventricular (brain) catheters and drainage (abdominal) catheters.

[0068] Shunting and other methods of removing excess CSF often involve creating a hole in the third ventricle region of the neurovasculature to remove excess CSF and reduce intracranial pressure. This procedure is often used instead of or in conjunction with shunting to provide a drainage route for CSF to return to the bloodstream. However, sealing this opening can be difficult. Hydrogels are a group of compounds that expand in response to specific stimuli. Hydrogels for vascular treatment purposes are often designed to expand based on contact with aqueous substances (e.g., the aqueous portion of blood) or pH (e.g., blood pH). In one embodiment, a hydrogel, such as, by way of non-limiting example, polyethylene glycol or polytetramethylene oxide, can be applied to the area to help seal the opening. In one embodiment, a portion of the distal tip of the ventricular catheter (meaning the terminal portion of the ventricular catheter within the neurovascular CSF accumulation point) utilizes a hydrogel to help seal the opening, such as, for example, about 5 centimeters from the distal tip. Alternatively, hydrogel can be applied using a syringe after the catheter is positioned in the desired location within a ventricle of the neurovasculature. Similarly, for intravascular placement of a shunt valve, a vein, such as the inferior petrosal sinus, is punctured to place the valve. Hydrogel can be applied to the tip of the shunt, where it anchors the shunt to the vessel wall and helps seal the puncture to secure the shunt in place.

[0069] Many of the embodiments presented herein address problems associated with clogged or malfunctioning ventricular catheters, and various mechanical devices and systems have been described to address this issue. This problem can also be addressed through an electronic communication system that utilizes a wireless communication protocol to monitor changes in intracranial pressure (ICP), whereby blockages or other problems associated with CSF drainage procedures result in significant increases in intracranial pressure (ICP). ICP is measured over a given time interval, and maximum and minimum pressures are stored and analyzed to provide a meaningful display of ICP, whereby significant deviations indicate problems with the shunt system. The information is then wirelessly transmitted via a communication protocol, such as, but not limited to, Bluetooth Low Energy (BLE), to provide advance warning of changes in ICP to alert the patient. This information is then wirelessly transferred to a portable wireless-enabled device, such as a wristwatch, cell phone, or mobile computer. The steps and components required for this system are shown in the flowchart of Figure 21.

[0070] The pressure sensor included in the flowchart of FIG. 21 is used to monitor ICP and, in one embodiment, uses a microelectromechanical (MEMS) silicon-based pressure sensor. Silicon-based pressure sensors utilize proportional changes in a resistive element located within the sensor. The pressure sensor can be located anywhere within the shunt system, including within the ventricular catheter, valve housing, or drainage catheter. Additionally, different pressure-sensing elements can be located in different areas of the shunt system (e.g., one within the ventricular catheter and one within the valve housing) to provide a broader ICP display and help identify where blockages are located. Alternatively, another pressure sensor can be implanted near the ventricular catheter so that the pressure physically represents ICP in the ventricular region where CSF accumulates.

[0071] The flowchart also includes an antenna system used to transmit data to a wireless-enabled device (such as a watch, smartphone, computer, or tablet). One embodiment of the antenna portion of the electrical system utilizes a non-magnetic conductive trace pattern (e.g., utilizing gold-plated copper, platinum, or beryllium) designed into the surface of the shunt catheter and connected to the antenna interface circuitry. The conductive section connects a measurement sensor (such as a pressure sensor) to the antenna to transmit relevant data, or connects a controller that compiles relevant data to the transmitting antenna. The conductive pattern is designed to have optical radio frequency transmission characteristics over a selected wireless communication protocol (e.g., BLE frequencies from 2.4 to 2.4835 GHz).

[0072] Another embodiment for the antenna portion of the electrical system utilizes a ventricular anchor. The ventricular anchor exits a CSF-retaining vessel in the neurovasculature, and the catheter is positioned intravenously, whereby the anchor serves to maintain the ventricular catheter in place. This embodiment utilizes a ventricular anchor made of a conductive material (e.g., stainless steel, platinum-cobalt-chromium, etc.) with dimensions for RF transmission characteristics at the required frequency, in which case the anchor itself functions as the antenna or serves as a conductive electrical communication medium for the antenna.

[0073] The electrical system's power requirements are relatively low, requiring approximately 3-4 microwatt-hours each time ICP is measured and the associated data transmitted. One embodiment utilizes an energy storage concept that utilizes a capacitive storage element embedded within the wall of the ventricular catheter. The capacitive storage element consists of two concentric tubes of different diameters, with the space between the two conductive tubes filled with a dielectric material. The dielectric has a sufficient dielectric constant to provide sufficient capacitance between the two tubes to store enough energy for the electrical system to operate. The capacitor is charged via an external charge source, such as an inductively coupled charging station or energy harvesting (e.g., thermal, RF, or piezoelectric energy) controlled by a charge controller. Alternatively, the electrical system utilizes a sealed, implantable battery, utilizing lithium-iodine or lithium-fluorocarbon batteries.

[0074] In one embodiment, the electrical communication system described above and shown in FIG. 21 passively measures ICP and transmits this information to an external device, which relays this information to the user. In another embodiment, the electrical system alters valve characteristics (e.g., loosens or tightens the valve to increase or decrease CSF output) based on the measured ICP data. As described above, because a certain amount of CSF is required, shunt valves cannot constantly output CSF; instead, they typically output CSF above a certain pressure. Typically, this system utilizes a mechanical valve that mechanically opens or releases CSF above a threshold pressure. Designing an optimal valve can be difficult in certain situations because each patient is different (e.g., each patient has different brain sizes and CSF production rates). However, in the electrical system described above, the monitoring system itself is coupled to the valve and can open or close the valve based on the calculated ICP, providing a customizable valve profile. In this way, when a certain threshold is exceeded, the electrical system communicates with the valve and opens the electromechanical valve. This threshold can be constantly updated based on observed phenomena or calibrated based on stored profiles available to the physician. The system also continuously monitors CSF and makes continuous small adjustments to control how the valve "opens," creating a constantly updated valve profile where small adjustments to the valve opening profile are made relatively continuously as needed. In this way, a master electronics system is used to monitor ICP, and this system is directly coupled to the valve to adjust the valve to allow more CSF flow through the valve or restrict CSF flow through the valve as needed.

[0075] One problem with shunts is the change in CSF drainage rate when a patient transitions from a supine or lying position (e.g., while sleeping) to an upright position. This change in movement can cause a sudden drainage of CSF due to gravity as the drainage catheter moves from a horizontal to a vertical position when the patient stands upright. However, this increased drainage can be undesirable because it is due to the patient's change in position, not a buildup of CSF. Excessive drainage of CSF can be dangerous because too little CSF in the neurovasculature can lead to ventricular collapse, vascular rupture, headaches, subdural hematomas, slit ventricle syndrome (small ventricles), too little cushioning in the brain, and / or reduced nutrient absorption and waste removal processes. One embodiment of the present invention addresses this problem by utilizing an electromechanical valve that uses sensors to measure CSF pressure and flow to regulate and control valve flow. One or more microaccelerometer sensors are integrated into the shunt valve or placed along the catheter tubing, and these sensors are used to detect patient movement and orientation (e.g., supine or standing). Once the shunt is implanted, the physician calibrates the microaccelerometer by creating baseline orientations of the patient in different body positions. Once calibrated, the accelerometer determines whether the patient is supine, standing, partially supine, partially standing, etc. When the accelerometer measures that the patient is moving from a supine / horizontal position to a standing position, a signal is sent to the electromechanical valve, which reduces the flow rate to prevent overdrainage of CSF. Small changes can occur when small changes are observed (e.g., when the patient goes from sitting to standing or from a slouched to an upright position). In addition to preprogrammed flow adjustments based on body posture, the CSF shunt can also be programmed with an AI algorithm whereby a downstream flow sensor (e.g., a flow sensor in the drainage catheter) is used to detect the effectiveness of the last event in which the valve was adjusted to prevent over-siphoning / over-draining of CSF. Valve settings based on various body postures are stored in the device's memory, and after each event, the program adjusts the electromechanical shunt valve to account for changes in body posture and the corresponding flow characteristics. The system accurately identifies optimal settings using stored historical data to prevent siphoning based on the observed phenomenon. In this way, the patient has optimal settings for siphoning prevention and reduces the need for visits to the doctor to adjust the valve. The system can also be used with the wireless system described above and shown in FIG. 21 to communicate and monitor ICP characteristics, where user posture is another measurement the system is configured to monitor and adjust based on the observed phenomenon.

Claims

1. A cerebrospinal fluid shunt comprising: A ventricular catheter; a plurality of slits along a portion of the ventricular catheter that facilitate the flow of cerebrospinal fluid into the ventricular catheter; a covering covering one or more of the plurality of slits.

2. The cerebrospinal fluid shunt of claim 1 , wherein the coating is bioabsorbable or biodegradable.

3. The cerebrospinal fluid shunt of claim 2, wherein the coating comprises a poly alpha-hydroxy acid or a polyester amide.

4. 3. The cerebrospinal fluid shunt of claim 2, wherein some slits include different amounts of coating to vary the cerebrospinal fluid inflow capacity through different slits of the ventricular catheter.

5. 3. The cerebrospinal fluid shunt of claim 2, wherein some slits include coatings with different absorption rates to vary the cerebrospinal fluid inflow capacity through different slits of the ventricular catheter.

6. The cerebrospinal fluid shunt of claim 2 , wherein the coating is a plasma protein adsorption inhibitor.

7. The cerebrospinal fluid shunt of claim 2, wherein the coating is poly 2-methoxyethyl acrylate.

8. 3. The cerebrospinal fluid shunt of claim 2, wherein the slits are of different sizes to vary the cerebrospinal fluid inflow capacity through different slits in the ventricular catheter.

9. A cerebrospinal fluid shunt comprising: A ventricular catheter; a plurality of slits along a portion of the ventricular catheter that facilitate the flow of cerebrospinal fluid into the ventricular catheter; a flushing mechanism spanning one or more of the plurality of slits, the flushing mechanism having a movable element that moves relative to the ventricular catheter; The cerebrospinal fluid shunt, wherein the movable element includes a protrusion configured to contact one or more portions of the plurality of slits when the movable element moves relative to the ventricular catheter.

10. The cerebrospinal fluid shunt of claim 9 , wherein the flushing mechanism further comprises a fixed element fixed relative to the movable element.

11. The cerebrospinal fluid shunt of claim 10, further comprising a spring connected to both the fixed element and the movable element.

12. The cerebrospinal fluid shunt of claim 9 , wherein the movable element includes a lumen and the protrusion projects from the lumen.

13. The cerebrospinal fluid shunt of claim 9 , wherein the fixation element includes a larger lumen than the ventricular catheter.

14. 10. The cerebrospinal fluid shunt of claim 9, wherein the movable element includes an inner lumen that is larger than an outer diameter of the fixed element.

15. The cerebrospinal fluid shunt of claim 9 , wherein the movable element is rotatable relative to the ventricular catheter.

16. A cerebrospinal fluid shunt comprising: A ventricular catheter; a plurality of slits along a portion of the ventricular catheter that facilitate the flow of cerebrospinal fluid into the ventricular catheter; a housing disposed over a portion of the ventricular catheter; a flushing mechanism disposed between the housing and the ventricular catheter, the flushing mechanism having a movable element that moves relative to the ventricular catheter; The cerebrospinal fluid shunt, wherein the movable element is configured to flush one or more of the plurality of slits in the ventricular catheter when the flushing mechanism moves relative to the ventricular catheter.

17. 17. The cerebrospinal fluid shunt of claim 16, wherein the flushing mechanism comprises a spring and a piston connected to the piston.

18. 18. The cerebrospinal fluid shunt of claim 17, wherein the piston includes an internal protrusion configured to contact one or more of the plurality of slits.

19. 18. The cerebrospinal fluid shunt of claim 17, wherein the piston includes an external protrusion configured to contact the housing.

20. The cerebrospinal fluid shunt of claim 16, wherein the movable element rotates relative to the ventricular catheter.

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