CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to United States Provisional Patent Application Serial No. 62/356,256, filed June 29, 2016 and entitled "SUBARACHNOID TO SAGITTAL SINUS CSF DRAINAGE SYSTEM," the entire contents of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present disclosure relates to devices and methods for accessing the subarachnoid space in a subject, and more particularly, to devices and methods that drain cerebrospinal fluid from the subarachnoid space into the cerebral venous sinuses.

BACKGROUND

[0003] Existing configurations for devices that are used to treat accumulation of excess fluid in a cranial space of a subject have addressed shunt designs, improved one-way valves, or other variations in the catheter system to decrease performance issues associated with catheters. However, such designs suffer from issues such as low fluid flow, susceptibility to blockages, and inadequate removal of excess fluid from the subarachnoid space of the brain and into the catheter.

[0004] Accordingly, there exists a continuing need for improved fluid drainage catheters and methods of use thereof.

SUMMARY

[0005] In an embodiment, an implantable device for drainage of fluid includes a flat proximal portion having one or more sidewalls and one or more openings disposed on each of the one or more sidewalls. The one or more openings provide a fluid inlet into the flat proximal portion. The implantable device further includes a distal portion fluidly coupled to the flat proximal portion. The distal portion includes an angled trajectory and a tip opening at a distal end of the distal portion. The tip opening provides a fluid outlet from the distal portion.

[0006] In another embodiment, a method for moving fluid in a subject includes providing an implantable device that includes a flat proximal portion having one or more sidewalls and one or more openings disposed on each of the one or more sidewalls and a distal portion fluidly coupled to the flat proximal portion. The one or more openings provide a fluid inlet into the flat proximal portion. The distal portion includes an angled trajectory and a tip opening at a distal end of the distal portion, the tip opening providing a fluid outlet from the distal portion. The method further includes providing a burr hole site, inserting the flat proximal portion of the implantable device through the burr hole site in a subarachnoid space of the subject, and placing the distal portion of the implantable device in a venous sinus in the subject.

[0007] In yet another embodiment, an implantable device for drainage of cerebrospinal fluid to treat hydrocephalus includes a flat proximal portion having one or more sidewalls and one or more openings disposed on each of the one or more sidewalls. The one or more openings provide a fluid inlet into the flat proximal portion. The implantable device further includes a central portion fluidly coupled to the flat proximal portion and a distal portion fluidly coupled to the central portion. The central portion includes a unidirectional valve and the distal portion includes an angled trajectory and a tip opening at a distal end thereof. The tip opening provides a fluid outlet from the distal portion.

[0008] These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0010] FIG. 1A depicts a perspective view of an illustrative intracranial catheter according to one or more embodiments shown and described herein;

[0011] FIG. IB depicts a perspective view of another illustrative intracranial catheter according to one or more embodiments shown and described herein;

[0012] FIG. 2 depicts a side view of another illustrative intracranial catheter according to one or more embodiments shown and described herein;

[0013] FIG. 3 depicts a side view of an illustrative intracranial catheter according to one or more embodiments shown and described herein; [0014] FIG. 4A depicts a perspective view of a portion of an illustrative intracranial catheter showing an angled trajectory at a portion to be placed in a dural venous sinus of a subject according to one or more embodiments shown and described herein;

[0015] FIG. 4B depicts a perspective view of a portion of an illustrative intracranial catheter and a corresponding plug according to one or more embodiments shown and described herein;

[0016] FIG. 5 depicts a perspective cross-sectional view of an illustrative intracranial catheter having a unidirectional valve therein according to one or more embodiments shown and described herein;

[0017] FIG. 6 depicts an end view of an illustrative intracranial catheter according to one or more embodiments shown and described herein;

[0018] FIG. 7A depicts a perspective view of an illustrative intracranial catheter having a balloon assist mechanism according to one or more embodiments shown and described herein;

[0019] FIG. 7B depicts a side view of the intracranial catheter having the balloon assist mechanism of FIG. 7A when inserted in a subject according to one or more embodiments shown and described herein;

[0020] FIG. 8A depicts a perspective cross sectional view of a subject's head, indicating illustrative placements of an intracranial catheter according to one or more embodiments herein;

[0021] FIG. 8B depicts an axial view of a subject's brain, indicating an illustrative placement of an intracranial catheter according to one or more embodiments shown and described herein;

[0022] FIG. 8C depicts a sagittal view of a subject's brain, indicating an illustrative placement of an intracranial catheter according to one or more embodiments shown and described herein;

[0023] FIG. 9 depicts a view of an illustrative intracranial catheter in place in a subarachnoid space as seen in a coronal view of a subject's brain according to one or more embodiments shown and described herein;

[0024] FIG. 10A depicts a side view of an illustrative tissue depressor that creates space for insertion of an intracranial catheter according to one or more embodiments shown and described herein;

[0025] FIG. 10B depicts a side view of another illustrative tissue depressor according to one or more embodiments shown or described herein; [0026] FIG. IOC depicts a side view of yet another illustrative tissue depressor according to one or more embodiments shown or described herein;

[0027] FIG. 11 depicts a cross- sectional side view of an illustrative burr hole site having an illustrative chamber plug that covers the burr hole site according to one or more embodiments shown and described herein;

[0028] FIG. 12 depicts a flow diagram of an illustrative method of inserting an intracranial catheter according to one or more embodiments shown and described herein; and

[0029] FIG. 13 depicts a side view of an illustrative method of inserting an intracranial catheter according to one or more embodiments shown and described herein. DETAILED DESCRIPTION

[0030] The embodiments described herein generally relate to devices and methods for recreating normal biological fluid flow patterns by reproducing the functions of arachnoid villi drainage of excess cranial fluid into the venous sinuses. More specifically, the embodiments described herein include an implantable device that is a catheter which includes a flat proximal portion, a distal portion, and a central portion disposed between the flat proximal portion and the distal portion. The device is implanted in a particular area of the subject's intracranial area to effect drainage, as described in greater detail herein.

[0031] The devices and methods described herein are particularly designed and constructed to span the ventricle producing fluid such as CSF and the subarachnoid/subdural spaces, which are distinctly different anatomic locations and compartments. The devices and methods described herein are further designed and positioned such that fluid produced in the ventricle is drained by the devices described herein due to the downstream location of the devices described herein from the fluid produced by the ventricle. Moreover, the devices and methods described herein allow for minimal blood loss and/or no air embolus and air entry into the venous system, which could potentially be fatal. The devices and methods described herein also allow for ease of recurrent access into the implantable device without exsanguinating or killing the subject, particularly young subjects.

[0032] Cerebrospinal fluid (CSF) is a ubiquitous fluid similar in composition to water that bathes the central nervous system structures in the cranial cavity and spinal canal. Fluid is formed in a continuous fashion at a rate that ranges between 0.2 to 0.7 ml per minute to a total amount of up to 600ml per day. This fluid is absorbed across several routes. These include, but are not limited to, the arachnoid villi into the venous sinus circulation and into the lymphatic vessels around the cranial cavity and spinal canal. The arachnoid villi form a one-way valve between the subarachnoid space and the dural venous sinuses. The arachnoid granulations are exposed to cerebral spinal fluid that resides in the subarachnoid space on the basal side and with the venous blood of the superior sagittal sinus on the apical side. This pathway is disrupted in individuals with hydrocephalus, which can lead to a buildup of fluid and subsequent increase in intracranial pressure. The subarachnoid space is the region around the brain and is bounded by dura matter, which also contains cerebrospinal fluid with a volume of 150ml out of a total of 500ml in the central nervous system.

[0033] Hydrocephalus, which is an abnormal accumulation of CSF within the brain, is a frequently encountered problem, both in adult and child subjects. Hydrocephalus is one of the most frequently encountered problems in neurosurgery, both in adults and in the pediatric population. This condition is commonly treated using a surgical procedure in which a tube, referred to as a "shunt," is placed into the patient's body. This device was introduced as a medical treatment of hydrocephalus in the 1950's, and has remained virtually unchanged for the past 50 years. This procedure involves placing a catheter into the cerebral ventricular space and diverting the fluid into a separate body cavity including the peritoneal or pleural space. Placing the catheter into the right ventricle of the cardiac chamber is also a method of draining the CSF into the venous system.

[0034] In contrast, the present disclosure relates to the treatment of fluid accumulation within the cranial cavity by permitting the flow of fluid from the subarachnoid space into the venous system. The treatment described herein may be utilized for hydrocephalus in addition to other conditions that may cause fluid accumulation. As such, the present disclosure is not related solely to the treatment of hydrocephalus or the drainage of CSF. Other fluids and conditions for which the devices and methods described herein can treat should generally be understood.

[0035] It should also be understood that the present disclosure is not solely related to fluid removal and redirection. That is, in some embodiments, the methods and devices described herein may further be used for the purposes of targeted drug delivery. For example, chemotherapy medication, ALS medication, Alzheimer's medication (e.g., chelating or enzymatic methods), stroke treatment medication (e.g., TPA), genetic (e.g., chromosomal) manipulation therapy, treatments for bacterial or viral infections, treatment for brain hemorrhage control, and/or the like may be delivered to particular areas (e.g., the subarachnoid space, sagittal sinus, etc.) that are accessed by the methods and devices described herein. [0036] FIG. 1A depicts an implantable device, generally designated 100, for drainage of fluid. In some embodiments, the implantable device 100 may be a catheter. The implantable device 100 may include a proximal portion 102, a distal portion 112, and a central portion 110 disposed between the proximal portion 102 and the distal portion 112.

[0037] In embodiments where the implantable device 100 is a catheter, it may be referred to as an intracranial catheter or a dural-sinus catheter. As such, the terms "system", "implantable device", "device", "drain", "drainage system", "drainage device", "catheter", "intracranial catheter" or "dural-sinus catheter" are interchangeable throughout the present disclosure.

[0038] The proximal portion 102 may generally be located in a proximal area 104 of the implantable device 100. In various embodiments, the proximal portion 102 is substantially flat. For example, the proximal portion 102 has a first major surface 101 and a second major surface 103 that are substantially planar with respect to one another and spaced a distance from one another, where the distance is less than a length and/or a width of the proximal portion 102, as described in greater detail herein. In another example, a cross section of the proximal portion 102 may have a flattened oval shape where the first major surface 101 and the second major surface 102 are substantially curved toward one another. Other designs that result in a substantially flat shape of the proximal portion 102 are contemplated and included within the scope of the present application. The substantially flat feature of the proximal portion 102 is advantageous because it provides a larger surface area relative to a non-flat proximal portion when the proximal portion 102 is inserted into the subarachnoid space of a subject. As such, a larger amount of tissue is compressed (e.g., brain, dura, etc.) by the proximal portion 102 when the proximal portion 102 is inserted, leaving additional space for free flow of fluid, as described in greater detail herein.

[0039] In some embodiments, the proximal portion 102 may also include one or more openings 108 on one or more sidewalls 109 of the proximal portion 102. As will be described in greater detail herein, the one or more openings 108 may function as fluid inlets to allow drainage of fluid into the implantable device 100 and away from a cranial space, such as the subarachnoid space. In addition, the location of the one or more openings 108 on the one or more sidewalls 109 may be such so as to prevent obstruction or blockage from the adjacent dura or brain structure. That is, the substantially flat features of the proximal portion 102 may compress an area of tissue in which it is inserted, creating a space for free fluid flow into the one or more openings 108, thereby avoiding an instance where tissue is pressed up against the one or more openings 108, which would block fluid flow. An area of the flat surface of the proximal portion 102 may vary, as described in greater detail herein. It should be understood that a larger area of the flat surface of the proximal portion 102 may provide increased fluid flow. More specifically, the flat profile of the proximal portion 102 allows for a greater area for the one or more openings 108 relative to a longitudinal design, such as a design employed by a typical tube catheter.

[0040] The distal portion 112 may be located in a distal area 116 of the implantable device 100. The distal portion 112 may be insertable into a venous sinus of a brain to allow drainage of fluid through the implantable device 100 and into the blood system via the venous system. A tip opening 118 at the end of the distal portion 112 may act as an outlet for fluid.

[0041] The central portion 110 of the implantable device 100 is generally disposed between the proximal portion 102 and the distal portion 112. The central portion 110 fluidly couples the proximal portion 102 to the distal portion 112. The central portion 110 includes a proximal end 110a and a distal end 110b. The proximal end 110a includes a connecting region where a distal end 106 of the proximal portion 102 is coupled to the central portion 110. The distal end 110b includes a connecting region where a proximal end 114 of the distal portion 112 is coupled to the central portion 110. The proximal end 110a and the distal end 110b may include one or more features for connecting to the proximal portion 102 and the distal portion 112 respectively, as described in greater detail herein. In some embodiments, the central portion 110 may be constructed of silicone such that the central portion 110 functions as a silicone flanged union of the proximal portion 102 and the distal portion 112.

[0042] The proximal portion 102, the central portion 110, and the distal portion 112 may generally be positioned relative to one another such that the proximal portion 102, the central portion 110, and a first section 112a of the distal portion 112 are generally in-line with one another. That is, the proximal portion 102, the central portion 110, and the first section 112a of the distal portion 112 are each generally extending in the same direction (e.g., along the +X/-X axis of the coordinate axes in FIG. 1A). The distal portion 112 may be bent or otherwise curved such that a second section 112b thereof extends in a direction that is not the same direction as the first section 112a thereof. For example, the second section 112b of the distal portion 112 may extend in a direction that is substantially perpendicular to the direction in which the first section 112a of the distal portion 112 extends (e.g., along the +Y/-Y axis of the coordinate axes in FIG. 1A). Other directions are also contemplated and are included within the scope of the present disclosure. Such a curvature or angled trajectory of the distal portion 112 may be formed by a user by bending the distal portion as necessary to fit a particular subject's anatomy. As such, the material used for the distal portion may be a deformable material. Deformable materials that are suitable for the various uses described herein should generally be understood. In some embodiments, the distal portion 112 may further include a shape memory component such that a particular shape and positioning is "remembered" by the distal portion 112 so that it can return to that shape and positioning after being deformed. This may allow the implantable device 100 to bend when a straightening stylet is removed from within the implantable device to allow for a better cannulation of the venous channel at the time of insertion, as described in greater detail herein.

[0043] In some embodiments, the various portions of the implantable device 100, including (but not limited to) the proximal portion 102, the central portion 110, and the distal portion 112 may be coupled to one another via one or more mechanical interlock devices. For example, one or more of the proximal portion 102, the central portion 110, and the distal portion 112 may include a fluid fitting such as Luer taper or the like that allows the various portions of the implantable device 100 to be coupled or decoupled without fluid leakage. Such embodiments may be particularly used when the implantable device 100 is placed within a subject as described herein so as to avoid fluid from crossing the blood brain barrier. Such mechanical interlock devices may also be used, for example, to allow insertion of a needle or the like into one or more portions of the implantable device 100 without allowing fluid to escape (e.g., insert a needle into a reservoir to deliver medication or other fluid to the reservoir, as described in greater detail herein).

[0044] The implantable device 100 may include one or more other deformable regions 120. That is, the proximal portion 102 may include one or more deformable regions 120, the central portion 110 may include one or more deformable regions 120, and/or the distal portion 112 may include one or more deformable regions 120. The various deformable regions 120 may generally allow the implantable device 100 (or portions thereof) be deformable during insertion to facilitate entry into the dural and sagittal sinus spaces, returning to their approximate original shape after insertion. For example, a deformable region 120 in the proximal portion 102 may facilitate introduction of the proximal portion under the dura, as described in greater detail herein.

[0045] Fluid may generally flow in a fluid direction D _f such that the fluid is received in the one or more openings 108 of the proximal portion 102, flows through the proximal portion 102, the central portion 110, and the distal portion 112, and out of the tip opening 118 of the distal portion 112, as described in greater detail herein. [0046] FIG. IB depicts the implantable device 100 having an alternative proximal portion 102'. As shown in FIG. IB, the alternative proximal portion 102' may be shaped and/or sized in such a manner so as to maximize the surface area of the alternative proximal portion 102'. For example, the first major surface 101 of the alternative proximal portion 102' and/or the second major surface 103 of the alternative proximal portion 102' may be substantially round. However, it should be understood that such a shape is merely illustrative, and the alternative proximal portion 102' may exhibit any other shape without departing from the scope of the present disclosure. In addition, the alternative proximal portion 102' may be made to any size. For example, a width W of the alternative proximal portion 102' may be, but is not limited to, about 8 millimeters (mm) to about 10 mm, including about 8 mm, about 8.5 mm, about 9 mm, about 9.5 mm, about 10 mm, or any value or range between any two of these values (including endpoints). As will be described in greater detail herein, the various shapes and/or sizes of the alternative proximal portion 102' may allow for greater fluid flow into the implantable device 100.

[0047] Also depicted in FIG. IB are one or more resonant strips 124 located on various portions of the implantable device 100. The one or more resonant strips 124 may each be wires or other components that are attached to an outer surface of the implantable device. The one or more resonant strips 124 may resonate the device when coupled to an external energy device, such as an ultrasound device, a radio frequency (RF) emitting device, and/or a laser energy emitting device. Such devices may be configured to improve the flow of fluid within the implantable device 100 by generating waves that are used to cause the fluid to flow. While the resonant strips 124 are only depicted in FIG. IB, it should be understood that the resonant strips 124 may be included in any of the embodiments described herein.

[0048] FIG. 2 depicts another embodiment of the implantable device 100 that contains a second central portion 170 disposed between the proximal portion 102 and the distal portion 112 and fluidly coupled to the proximal portion and the distal portion 112. In some embodiments, the second central portion 170 may be disposed between the distal portion 112 and the central portion 110, as shown in FIG. 2. However, it should be understood that the second central portion 170 may also be disposed between the proximal portion 102 and the central portion 110. In some embodiments, the second central portion 170 may replace the central portion 110. In still other embodiments, the second central portion 170 may be integrated with the central portion 110. [0049] The second central portion 170 may include one or more components that are particularly configured to provide targeted drugs to particular areas of a subject, such as (but not limited to) the subarachnoid space, the sagittal sinus, and/or the like. For example, chemotherapy medication, ALS medication, Alzheimer's medication (e.g., chelating or enzymatic methods), stroke treatment medication (e.g., TPA), genetic (e.g., chromosomal) manipulation therapy, treatments for bacterial or viral infections, treatment for brain hemorrhage control, and/or the like may be delivered to the particular areas via the second central portion 170 of the implantable device 100. Illustrative examples of various components that are particularly configured to provide targeted drugs include, but are not limited to, a reservoir 172.

[0050] The reservoir 172 may be particularly shaped and/or sized to contain a particular amount of material (e.g., fluid) therein. The particular amount of material may correspond to a particular amount of medication to be delivered by the implantable device 100, for example. The reservoir 172 may be fluidly coupled to the various portions of the implantable device 100 such that the materials within the reservoir 172 are transported from the reservoir 172 to the subarachnoid/subdural space, and/or the like via the various portions, including the proximal portion 102 and/or the distal portion 112. The reservoir 172 may include a seal or the like in a portion thereof such that an internal portion of the reservoir 172 can be accessed for dispensing medication or the like into the reservoir. That is, a user may access the internal portion of the reservoir 172 and dispense the medication into the reservoir 172 such that the medication can be distributed to the various other portions of the implantable device 100, as described herein.

[0051] In some embodiments, the reservoir 172 may be constructed and configured such that the reservoir 172 can hold a pressurized fluid therein. That is, the reservoir 172 may be constructed of a particular material that is able to withstand an increased fluid pressure. In addition, the reservoir 172 may include one or more various components, such as valves or the like such that a particular fluid pressure is maintained in the reservoir 172. A pressurized fluid may be necessary in the reservoir to ensure that the medication contained within the fluid can be dispensed to particular locations, as described herein. That is, the pressure of the fluid within the reservoir 172 may cause a force that directs fluid in a particular direction when the fluid exits the reservoir 172 to the various other portions of the implantable device 100.

[0052] In some embodiments, the reservoir 172 may be positioned adjacent to a burr hole in a subject's skull such that the reservoir 172 is accessible. That is, medication or the like may be distributed to the reservoir (and subsequently the various other portions of the implantable device 100) via the burr hole. For example, a user may remove a chamber plug or the like (as described in greater detail herein) from the burr hole to reveal at least a portion of the reservoir 172, which can receive the medication and/or the like.

[0053] It should be understood that the introduction of medication to targeted areas via use of the second central portion 170 and/or the various components thereof may allow for use of certain medications that would otherwise not be suited for targeted therapy. More specifically, medications that are not designed to cross the blood-brain barrier may be delivered using the implantable device 100 with the second central portion 170, as the implantable device 100 crosses the blood-brain barrier.

[0054] FIG. 3 depicts additional details regarding the size of various portions of the implantable device 100 according to various embodiments. For example, the proximal portion 102 may have a first length li, the central portion 110 may have a second length 1 ₂ , and the distal portion 112 may have a third length 1 ₃ . The first length li of the proximal portion 102 may be an overall length of the proximal portion 102, such as, for example, an average distance between a first end 102a and a second end 102b of the proximal portion 102 and/or a distance between the proximal area 104 of the implantable device 100 and the distal end 106 of the proximal portion 102. In some embodiments, the first length li of the proximal portion 102 may be a straight line length of the proximal portion 102 that does not take into account various curved portions, bent portions, or the like of the proximal portion 102 (i.e., when traversing the proximal portion 102 along the +X/-X axis of the coordinate axes of FIG. 3). Illustrative examples of the first length li may include, but are not limited to, about 10 mm to about 12 mm, including about 10 mm, about 10.25 mm, about 10.5 mm, about 10.75 mm, about 11 mm, about 11.25 mm, about 11.5 mm, about 11.75 mm, about 12 mm, or any value or range between any two of these values (including endpoints).

[0055] The second length 1 ₂ of the central portion 110 may be an overall length of the central portion 110, such as, for example, an average distance between the proximal end 110a and the distal end 110b thereof. In some embodiments, the second length 1 ₂ of the central portion 110 may be a straight line length of the central portion 110 that does not take into account various curved portions, bent portions, or the like of the central portion 110. Illustrative examples of the second length 1 ₂ may include, but are not limited to, about 8 mm to about 12 mm, including about 8 mm, about 8.5 mm, about 9 mm, about 9.5 mm, about 10 mm, about 10.5 mm, about 11 mm, about 11.5 mm, about 12 mm, or any value or range between any two of these values (including endpoints). [0056] The third length 1 ₃ of the distal portion 112 may generally correspond to the length of the first section 112a of the distal portion 112. That is, the third length 1 ₃ may be a distance between a first end 113a of the distal portion 112 and an angled end 113b of the distal portion 112. It should be understood that the angled end 113b of the distal portion 112 refers to a surface of the distal portion 112 that is the furthest distance from the first end 102a of the proximal portion 102 when the implantable device is traversed along the +X/-X axis of the coordinate axes of FIG. 3. Illustrative examples of the third length 1 ₃ may include, but are not limited to, about 4 mm to about 6 mm, including, about 4 mm, about 4.5 mm, about 5 mm, about 5.5 mm, about 6 mm, or any value or range between any two of these values (including endpoints).

[0057] Accordingly, the total length 1χ may generally be the combined lengths of the first length li, the second length 1 ₂ , and the third length 1 ₃ . In some embodiments, the total length 1 _T may be less than the combined lengths of the first length li, the second length 1 ₂ , and the third length 1 ₃ because the various portions may fit inside one another when coupled (e.g., the central portion 110 may be partially inserted within the proximal portion 102 and/or the distal portion 112). Illustrative examples of the total length 1χ include, but are not limited to, about 22 mm to about 30 mm, including about 22 mm, about 22.5 mm, about 23 mm, about 23.5 mm, about 24 mm, about 24.5 mm, about 25 mm, about 25.5 mm, about 26 mm, about 26.5 mm, about 27 mm, about 27.5 mm, about 28 mm, about 28.5 mm, about 29 mm, about 29.5 mm, about 30 mm, or any value or range between any two of these values (including endpoints). In some embodiments, the total length 1 _T may be about 25 mm to about 27 mm. It should be understood that the total length 1 _T may correspond to a length that allows the implantable device 100 to extend between the subarachnoid space to the venous system of a subject when the implantable device 100 is implanted in the subject, as described herein.

[0058] In various embodiments, the central portion 110 may have a diameter d ₂ . The diameter d ₂ of the central portion 110 may be an average diameter across the entire second length 1 ₂ or may be a diameter of a particular section of the central portion 110, such as, for example, the section being the largest in size. Illustrative examples of the diameter d ₂ of the central portion 110 may include, but are not limited to, about 2 mm to about 3 mm, including about 2 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, about 2.8 mm, about 2.9 mm, about 3 mm, or any value or range between any two of these values (including endpoints).

[0059] In various embodiments, the second section 112b of the distal portion 112 may have a height h ₃ . That is, the height h ₃ may correspond to a distance between the first section 112a of the distal portion 112 and the tip opening 118 of the distal portion 112. In some embodiments, the height h ₃ of the second section 112b of the distal portion 112 may be about 7 mm to about 9 mm, including about 7 mm, about 7.5 mm, about 8 mm, about 8.5 mm, about 9 mm, or any value or range between any two of these values (including endpoints).

[0060] Other various portions of the implantable device 100 may also have particular dimensional aspects. For example, the proximal portion 102 may have a distance di between the first major surface 101 and the second major surface 103 thereof. The distance di may be, for example, about 2 mm to about 3 mm, including about 2 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, about 2.8 mm, about 2.9 mm, about 3 mm, or any value or range between any two of these values (including endpoints). The distance di may be such that the proximal portion 102 is thin enough to fit within the subarachnoid space of a subject when the implantable device 100 is implanted in a subject as described herein.

[0061] In some embodiments, the one or more openings 108 in the proximal portion

102 may be spaced at a particular distance from one another and/or may be sized/shaped in a particular manner so as to allow a particular amount of fluid to flow into the implantable device 100. For example, in embodiments having a plurality of openings 108 in the proximal portion 102, each of the plurality of openings 108 may have a particular spacing S between one another. The spacing S generally refers to a distance between two of the plurality of openings 108, which may be measured between facing edges of the plurality of openings 108, between corresponding edges of each of the plurality of openings 108, from a center of each of the plurality of openings 108, or the like. The spacing S may be, for example, about 1 mm to about 3 mm, including about 1 mm, about 1.25 mm, about 1.5 mm, about 1.75 mm, about 2 mm, about 2.25 mm, about 2.5 mm, about 2.75 mm, about 3 mm, or any value or range between any two of these values (including endpoints). In addition to the spacing S, each of the one or more openings 108 may have a particular diameter d. The diameter d may be, for example, an average diameter from one edge to an opposite edge, an exact diameter in instances where the opening 108 has a circular shape, or the like. The diameter d may be, for example, about 0.5 mm to about 1.5 mm, including about 0.5 mm, about 0.75 mm, about 1 mm, about 1.25 mm, about 1.5 mm, or any value or range between any two of these values (including endpoints).

[0062] In some embodiments, the tip opening 118 of the distal portion 112 may have a particular shape and/or size, such as, for example, a tip opening diameter d ₃ . The tip opening diameter d ₃ may be an average diameter, an actual diameter, and/or the like. In some embodiments, the tip opening diameter d ₃ may be about 1 mm to about 2 mm, including about 1 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2 mm, or any value or range between any two of these values (including endpoints). It should be understood that the tip opening diameter d ₃ may be particularly shaped and/or sized to allow a particular amount of fluid to flow therethrough. In addition, the tip opening 118 may be particularly sized to accommodate different dural-sinus sizes of different subjects (e.g., subjects of a particular age group or the like).

[0063] As previously described herein, the central portion 110 may be particularly shaped such that it can be fluidly coupled to the proximal portion 102 and/or the distal portion 112. That is, proximal and distal ends of the central portion 110 may have specialized features for connecting, respectively, with the proximal portion 102 and the distal portion 112 of the implantable device. As such, the proximal portion 102 may include an end portion which is configured to fit the proximal end of the central portion 110. The proximal end and distal end of the central portion 110 may be configured to snugly fit the proximal portion 102 and the distal portion 112, respectively. For example, as shown in FIG. 4A, the central portion 110 may include one or more mating features 130 that allow the central portion 110 to mate with the various other portions of the implantable device 100 (FIG. 1A). Such mating features 130 are not limited by the present disclosure and may be any mating feature now known or later developed. For example, the mating feature 130 may be a flange, one or more ribs, and/or the like that allow for the various other portions (e.g., the proximal portion 102 (FIG. 1A) and/or the distal portion 112) to be placed thereover and held in place by the flange, one or more ribs, and/or the like. In some embodiments, the mating feature may be a Luer taper or the like, as described herein.

[0064] The various portions of the implantable device 100 (FIG. 1A), including the proximal portion 102, the central portion 110, and the distal portion 112 may be separable from one another. For example, it may be desirable to separate one or more portions of the implantable device 100 (FIG. 1A) after a procedure has been completed and abandon certain portions (i.e., allow certain portions to remain within the subject's body). As such, it may be necessary to plug one or more portions remaining within the subject body upon abandonment to avoid unnecessary fluid flow or the like. For example, as shown in FIG. 4B, the distal portion 112 may be detachable from the various other portions of the implantable device 100 (FIG. 1A) and an opening in the first end 113a of the distal portion 112 may be plugged with a plug 132. The plug 132 may be shaped and/or sized to correspond to the opening in the first end 113a of the distal portion 112 such that it can be inserted to prevent fluid flow. In some embodiments, the distal portion 112 may be detachable from the various other portions of the implantable device 100 (FIG. 1A) when it is not needed to drain fluid (i.e., when the implantable device is used for the purposes of delivering medication).

[0065] FIG. 5 depicts a view of various components inside the implantable device

100 according to various embodiments. Each of the various portions of the implantable device 100, including the proximal portion 102, the central portion 110, and the distal portion 112 is hollow such that a bore 134 runs through each portion. In addition, as previously described herein, the various portions of the implantable device 100 are fluidly coupled to one another such that fluid may move between the hollow bores 134 of the respective portions.

[0066] In some embodiments, the central portion 110 may include a valve 136 that is particularly configured to restrict fluid flow in a particular direction. For example, the valve 136 may be a check valve that prevents a backflow of blood into the subarachnoid space when the implantable device 100 is implanted in a subject as described herein. That is, the valve 136 may ensure unidirectional flow of fluid inside the implantable device 100. More specifically, the fluid may only flow in the fluid direction D _f , such as, for example, CSF flow from the subarachnoid space to the venous sinus. One illustrative example of a check valve may be a ball-in-cone valve, which includes a valve ball 137 and a biasing assembly 138 (e.g., a spring), such as, for example, the miniNav™ valve (Aesculap, Inc., Center Valley, PA). The biasing assembly 138 may bias the valve ball 137 in the proximal direction (e.g., along the -X direction of the coordinate axes of FIG. 5) such that the valve ball blocks fluid flow into the hollow bore 134 of the central portion 110 from the hollow bore 134 of the proximal portion 102. The biasing force of the biasing assembly 138 on the valve ball 137 may provide a particular valve opening pressure. As soon as a fluid pressure (e.g., the intraventricular pressure) exceeds the valve opening pressure, the biasing assembly 138 is compressed, the valve ball 137 moves out of its biased position (e.g., out of a cone), thereby providing an opening in the hollow bore 134 to allow fluid to flow therethrough. As such, the CSF is drained out through the gap that opens as a result of the valve ball 137 movement when the implantable device 100 is implanted in a subject as described herein. The valve opening pressure may be adjustable such that a particular pressure can be selected according to a particular subject's symptoms. For example, the miniNav™ is available with four pressure levels. Postoperatively, the pressure level of each valve can be recognized by the shape of the valve shell. For instance, a valve with concave (inward-curving) outlines at the proximal end and convex (outward-curving) contours at the distal end has an opening pressure of about 5 cm H ₂ 0.

[0067] It should be understood that the valve 136 is not limited to a check valve. Other valves or similar devices may also be used without departing from the scope of the present disclosure. For example, in some embodiments, the valve 136 may include integral flow limiting portions of the design thereof, such as flap valves or the like that are integrated into a structure of the central portion 110 utilizing an appropriate material change of durometer in that region of the device.

[0068] FIG. 6 depicts an end view of the implantable device 100 according to various embodiments. As previously described herein, the distal portion 112 may include an angled trajectory. That is, the distal portion 112 may be bent or otherwise angled/curved such that the second section 112b thereof extends in a direction that is not the same direction as the first section 112a thereof. The distal portion 112 may be angled, for example, such that the distal portion 112 can be placed against blood flow to prevent the formation of blood clots over the tip opening 118. However, it should be understood that this is merely illustrative. In some embodiments, the distal portion 112 may be placed with the blood flow, particularly in embodiments where the implantable device 100 is used to provide medication or the like to a subject. As previously described herein, the tip opening 118 may be particularly sized and/or shaped to accommodate different sagittal, transverse, or sigmoid sinus sizes of different subjects. As such, it should be understood that the distal portion 112 may include various interchangeable sizes of tips such that the tip opening 118 can be adjusted as needed.

[0069] In some embodiments, a balloon may be used for obstruction of the blood flow when replacing the implantable device, specifically when the distal portion 112 thereof is removed from the sagittal sinus for replacement or permanent replacement. FIGS. 7 A and 7B depict an illustrative balloon 140. More specifically, FIG. 7A depicts a single balloon 140 that is placed around the circumference of the distal portion 112 adjacent to the sinus wall 203. The balloon 140 may be placed adjacent to an exterior surface or an interior surface of the sinus wall 203. When the balloon 140 is inflated, it may compress the deformable region 120 of the distal end 112 such that fluid cannot flow therethrough. FIG. 7B depicts an alternative embodiment of the balloon 140, wherein the balloon 140 includes a first portion 140a and a second portion 140b. The first portion is placed around the distal portion 112 adjacent to a first surface 203a of the sinus wall 203 and the second portion 140b is placed around the distal portion 112 adjacent to a second surface 203b of the sinus wall 203. The first and second portions 140a, 140b are then inflated to restrict fluid flow through the distal portion 112 by compressing the deformable region 120.

[0070] In operation, the implantable device 100 is operable to cause drainage of various fluids, such as cerebrospinal fluid for treatment of hydrocephalus. The implantable device 100 may be inserted through a burr hole site such that the flat proximal portion is placed in a subarachnoid space and the distal portion of the catheter is placed in a venous sinus either with or against blood flow, thereby allowing the implantable device to drain fluid from the subarachnoid space into the venous sinus or transmit medication to the subarachnoid space and/or the venous sinus.

[0071] In some embodiments, it may be necessary to create the burr hole and place the implantable device 100 in a particular location so as to ensure correct operation of the implantable device 100, minimize injury to the subject, and/or the like. For example, the bun- hole may be located in the frontal lobe or in the occipital lobe. Two illustrative locations, Location A and Location B of particular placement locations are depicted in FIGS. 8A-8C. The particular locations of Location A and Location B decrease a size and/or number of necessary incisions. As shown in FIGS. 8A and 8B, Location A may be at the axial center of the crown in the frontal lobe. As shown in FIGS. 8 A and 8C, Location B may be in the occipital lobe region. It should be understood that Location A and Location B are merely illustrative, and other locations are contemplated.

[0072] FIG. 9 provides a more detailed view of insertion of the implantable device

100 according to one or more embodiments. The various portions of a subject's intracranial area depicted in FIG. 9 include the superior sagittal sinus 200, the arachnoid mater 202, the subarachnoid space 204, the pia mater 206, the arachnoid trabeculae 208, various veins 210 including cerebral veins 212, bone 216 (e.g., the skull), dura mater 218, subdural space 220, arachnoid granulation villi 222, a longitudinal fissure 224, and the cerebral cortex 226.

[0073] As shown in FIG. 9, the implantable device 100 is designed to slide over the surface of the brain and into the subarachnoid space. The proximal portion 102 of the implantable device 100 is inserted into the subarachnoid space 204 and the distal portion 112 of the implantable device 100 is inserted into the venous sinus of the brain (i.e., the superior sagittal sinus 200) to allow drainage of the fluid (e.g., CSF) through the implantable device 100 and into the blood system via the venous sinus.

[0074] In various embodiments, to ensure that the implantable device 100 and/or a portion thereof is appropriately positioned (e.g., within the subarachnoid space 204 and/or the superior sagittal sinus 200) and/or prevent damage to tissue (e.g., the brain) when the implantable device 100 is inserted, it may be necessary to compress tissue prior to insertion to create a space for the implantable device 100 and/or a portion thereof. FIGS. 10- IOC depict illustrative examples of various tissue depressors 300, 300', 300" (which may also be referred to as spatulas) that may be used to create such a space. As particularly indicated in FIG. 10A, a tissue depressor 300 may be inserted into the target space (e.g., the subarachnoid space) and may compress the tissue to create space for the implantable device 100. The implantable device 100 is subsequently moved into position and the tissue depressor 300 may then be removed. The tissue depressor 300 depicted in FIG. 10A may be substantially L-shaped. However, it should be understood that the tissue depressor 300 may have other shapes and/or sizes that may be more sufficient for compressing tissue and creating space for the implantable device, which may be based, for example, on the anatomy of the subject, the age of the subject, the location in which the implantable device 100 is placed, and/or the like. For example, an alternative tissue depressor 300' is depicted in FIG. 10B. The alternative tissue depressor 300' may have a shape that differs from the L-shaped structure of the tissue depressor 300 depicted in FIG. 10A (e.g., an inversely tapered shape). In another example, a third tissue depressor 300" is depicted in FIG. IOC. The third tissue depressor 300" may be curved. In some embodiments, any one of the various tissue depressors 300, 300', 300" may have an offset angled handle to facilitate use. In some embodiments, any one of the various tissue depressors 300, 300', 300" may have sidewalls that may be used to provide a guide for insertion of the implantable device 100 so as to ensure the implantable device 100 is accurately placed according to the sidewalls. In some embodiments, any one of the various tissue depressors 300, 300', 300" may include one or more guide marks 302 (FIG. IOC) thereon, where the guide marks 302 correspond to a particular depth, location, and/or the like such that a user inserting the implantable device 100 is guided to a particular depth, location, or the like via the guide marks 302.

[0075] In addition to the various tissue depressors 300, 300', 300", one or more other devices may also be used to assist in inserting the implantable device 100. For example, a catheter introducer may be any device that can cannulate a venous channel and prevent the backflow of blood, air suction, and/or the like into the venous channel during insertion of the implantable device 100. In some embodiments, such a catheter introducer may include one or more membranes that are particularly configured to prevent backflow of fluid. For example, a first membrane may have a permanent hole within and a second membrane may have a memory slit therein to allow the implantable device 100 to be inserted. [0076] In some embodiments, it may be necessary to abandon one or more portions of the implantable device 100. As such, in addition to (or an alternative of) the plug 132 (FIG. 4B), a chamber plug 150 may be inserted. That is, the burr hole site (e.g., an opening 217 in the bone 216) may receive the chamber plug 150. The chamber plug 150 may generally cover the burr hole site. The chamber plug 150 may be used to prevent bone ingrowth and allow for a mechanism to resonate the implantable device 100 with radio frequency (RF), mechanical energy, and/or ultrasonic energy in order to control the flow within the implantable device 100. For example, a transducer or an ultrasonic emitter 152 may be attached to a bottom of the chamber plug 150. The transducer or ultrasonic emitter 152 may communicate with the resonant strips 124 (FIG. IB) located on the surface of the implantable device 100 for resonation of the implantable device 100. The ultrasonic emitter 152 may also be used to image a morphology of the implantable device 100 and determine if any obstruction is occurring at a particular location within the implantable device, such as, for example, the tip opening 118 (FIG. 1A). The chamber plug 150 may be constructed of one or more radiolucent and/or non-magnetic materials. A nonlimiting example of such a material may include polyether ether ketone (PEEK). Other materials are also contemplated.

[0077] While not depicted in FIG. 11, the chamber plug 150 may further be coupled to a transducer. The transducer may resonate the resonant strips 124 on the implantable device 100 for flow control or for imaging a morphology of the implantable device.

[0078] FIGS. 12 and 13 depict a method of inserting the implantable device according to various embodiments. For example, at step 405, a lumbar puncture may be performed, as shown in part A of FIG. 13. Still referring to FIG. 12, in addition to the lumbar puncture, a radio-opaque, MRI contrast, or fluorescent dye may be injected. The dye may later be collected from a peripheral venous stick and tested for the function of the implantable device (i.e., to ensure the implantable device is appropriately placed). More specifically, at step 410, the time the lumbar puncture is completed and the dye inserted is recorded and the recorded time is used as a baseline measurement of venous outflow of fluid via the sagittal sinus at step 415. When dye is observed within the sagittal sinus, the time is measured at step 420.

[0079] Further, utilizing x-ray, CT, Fluoroscopy, MRI, or other such imaging modalities, the presence of the dye is used to localize the sagittal sinus on the skull and determine an exact placement of a burr hole.

[0080] Once the placement is determined, the burr hole may be created at step 430, as further indicated in part B of FIG. 13. Still referring to FIG. 12, this may generally be completed via any burr hole creation procedure now known or later developed. In some embodiments, creation of the burr hole may include creation of a linear incision of about 2 cm in length that is placed over the sinus. The burr hole may be, for example, an ellipsoid opening in the bone (coronal plane) that is sufficiently shaped and/or sized to receive the implantable device therein, as described herein. In addition to creating a burr hole, an opening in the dura may be created at step 435. This may generally be completed via any dura opening procedure now known or later developed. The opening in the dura may also be shaped and/or sized to receive the implantable device therein, as described herein.

[0081] Part C of FIG. 13 shows an open space in the sinus for insertion of the implantable device. However, if additional space is needed to insert the implantable device, the tissue depressor described herein may be inserted to create such a space in the subarachnoid space at step 440 of FIG. 12. As such, a pressure may be applied to tissue to compress the tissue and create the necessary space. The implantable device may then be inserted at step 445 and shown in part D of FIG. 13. Insertion of the implantable device may be assisted via ultrasound to isolate the sinus. In some embodiments, insertion of the implantable device may include creating a small slit in the adjacent dura to slide in the proximal portion. The distal portion is connected to the central portion, which is then secured to the proximal portion. The distal catheter is then pushed into the sagittal sinus. A cover is then placed in the burr hole site. The wound is closed in a typical sterile fashion.

[0082] Insertion of the implantable device according to step 445 may also be include passing a 22-25 solid gauge needle into the sagittal sinus, passing a dilator over the needle into the sagittal sinus while maintaining a tight internal seal around the needle and while producing both an internal and external flange seal to the sagittal sinus, withdrawing the needle with the internal seal maintaining control of any leakage of blood from the sagittal sinus, directionalizing the dilator such that its placement into the sagittal sinus is oriented in such a manner as to ensure proper orientation of the distal portion of the implantable device such that the tip opening thereof points into (against) the flow of venous blood. The dilator has an internal shape such that, when the distal portion of the implantable device is passed through the internal seal, it maintains a seal against any outward flow of blood while assuring that during implantable device insertion, the tip opening of the implantable device is pointed into the flow (against) of the venous blood. In addition, the dilator may maintain a permanent elastic seal around the implantable device at all times. If replacement of the implantable device is ever required, the dilator will allow exchange of the original implantable device with a replacement without blood loss. [0083] In some embodiments, insertion may further include use of an introducer device. The introducer device may cannulate the venous channel and prevent backflow of blood or air suction into the venous channel. The introducer device may further house two membranes inside the system. One membrane may have a permanent hole within and another membrane may have a memory slit to allow for device insertion.

[0084] In some embodiments, a bioseal or the like may be provided after insertion of the implantable device, so as to seal the dura and avoid leakage of fluid therefrom (e.g., CSF). Similarly, a bioseal adhesive may be used to seal the sagittal sinus from leaking fluid (e.g., blood).

[0085] Insertion of the device as described with respect to FIGS. 12 and 13 may allow the device to drain fluid as described herein and/or deliver medication to targeted areas as described herein. As such, the method may further include a step of draining the fluid from the subarachnoid space into the venous sinus, a transverse sinus, and/or a sigmoid sinus of the subject and/or delivering medication to the subarachnoid space, the venous sinus, a transverse sinus, and/or a sigmoid sinus of the subject.

[0086] It should now be understood that the devices and methods described herein relate to an implantable device including a proximal portion inserted into the subarachnoid space of a subject and a distal portion inserted into a venous sinus of a subject. The proximal portion and the distal portion are fluidly coupled to one another by a central portion that includes a valve. The implantable device, when inserted as described above, allows fluid, particularly CSF, to flow from the subarachnoid space into the venous sinus. Flow of the fluid may particularly be facilitated by the flat shape of the proximal portion having openings on sidewalls thereof.

[0087] While particular embodiments and aspects of the present disclosure have been illustrated and described herein, various other changes and modifications can be made without departing from the spirit and scope of the disclosure. Moreover, although various aspects have been described herein, such aspects need not be utilized in combination. Accordingly, it is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the embodiments shown and described herein.