Self-adjusting hydrocephalus valve

Abstract

A system and method for accurately measuring pressure (Pp) within a person's brain using fully implanted or partially external hardware. The system includes: a first pressure transducer configured to measure cerebrospinal fluid pressure (Pcsf) within a ventricle of the brain; a second pressure transducer configured to indirectly measure a second pressure (Pp) within the space of the brain; and an implantable adjustable valve controller configured to calculate an effective pressure difference (Pei=Pcsf-Pp) between the measured pressures Pcsf and Pp and determine whether the measured value of the effective pressure difference represents a true secondary pressure.

Description

Background Art

[0001] Hydrocephalus is a condition associated with an enlargement of the volume of the ventricles caused by a net accumulation of cerebrospinal fluid (CSF) within the ventricles of the brain. Non-communicating hydrocephalus (obstructive) or high-pressure hydrocephalus (HPH) is hydrocephalus associated with an obstruction in the ventricular system or CSF flow pathway, and is usually characterized by an increase in cerebrospinal fluid (CSF) pressure. HPH can also result when there is no obstruction in the ventricular flow pathway, but an obstruction occurs where the CSF is drawn from the ventricular system into the bloodstream. In contrast, a communicating (or non-obstructive) form of hydrocephalus can also occur, which is not caused by a visible (i.e., identifiable) obstruction in the flow of cerebrospinal fluid. Normal pressure hydrocephalus (NPH), a form of communicating hydrocephalus in which there is an enlargement of the volume of the ventricles at nearly normal CSF pressure, is a clinical condition that primarily affects the elderly. In this type of hydrocephalus, the CSF pathway is intact and drainage into the bloodstream is not impaired. NPH is characterized by three symptoms known as the Hakim triad associated with enlarged ventricular volume in the absence of increased intracranial pressure:

[0002] Movement disorders (primarily gait disorders) usually occur first;

[0003] Incontinence (primarily urinary incontinence), and

[0004] ·dementia.

[0005] Depending on severity and progression, one, two, or all three symptoms may be present, with gait disturbance usually being the presenting symptom. In summary, NPH manifests as enlargement of the cerebral ventricles in the setting of normal CSF pressure.

[0006] NPH is a known and distinct clinical condition that justifies its differential diagnosis from other brain atrophies and dementias. Unlike most dementias, dementia associated with NPH is reversible with treatment through shunt implantation.

[0007] The goal of treatment for all forms of hydrocephalus is to reduce the volume of the ventricles by lowering the pressure in the ventricles, resulting in normalization of the ventricular volume. Both types of hydrocephalus (HPH and NPH) are usually treated by implanting a shunt into the cerebral fluid compartment that drains excess CSF from the ventricles or from the lumbar subthecal space (which communicates with the cerebral fluid compartment in communicating hydrocephalus). Examples of such shunts include:

[0008] ventriculoatrial (VA) shunts, which move fluid from the ventricles to the right atrium of the heart,

[0009] ventriculoperitoneal (VP) shunts, which transfer fluid from the ventricles to the peritoneum, and

[0010] • Lumbar peritoneal (LP) shunt, which diverts CSF from the lumbar region to the peritoneum.

[0011] Ventricular shunts can be used in patients with either communicating or non-communicating hydrocephalus, but lumbar shunts can only be implanted in patients with communicating hydrocephalus.

[0012] These shunts typically include:

[0013] an inflow catheter, such as a cerebral catheter inserted through the brain parenchyma into the ventricle (for a ventricular shunt) or a lumbar catheter inserted through a hollow needle into the lumbar spinal sheath space (for a lumbar shunt),

[0014] a one-way valve system that controls fluid pressure from the ventricles or lumbar region, and

[0015] An outflow catheter, which is inserted into a reservoir in the body, such as the jugular vein (with the tip advanced toward the right atrium of the heart) or the peritoneal cavity, from which CSF is drawn, thereby bypassing the obstruction in cases of noncommunicating or obstructive hydrocephalus and reducing CSF pressure to below parenchymal pressure (and normalizing ventricular volume) in cases of NPH.

[0016] Ventriculoatrial shunts, ventriculoperitoneal shunts, and lumbar peritoneal shunts are available utilizing either fixed pressure or variable pressure (programmable or adjustable) valve mechanisms, as discussed further below.

[0017] Additionally, an external drainage system (EDS) to drain from the ventricles into a drainage bag (external ventricular drainage system or EVDS) or from the lumbar spinal space into a drainage bag (external lumbar drainage system or ELDS) may be used for a few weeks as a temporary procedure prior to permanent placement of a shunt to manage intracranial pressure (ICP) or to manage conditions including but not limited to infection, intraventricular hemorrhage, elevated CSF protein, etc., or as a screening procedure for NPH to determine if an implantable shunt is a management option. Summary of the invention

[0018] There is a need in the art for self-regulating hydrocephalus valves (implantable and external) for treating hydrocephalus and related disorders of the cerebrospinal fluid (CSF) space to optimize the shunt for the specific condition(s) being treated, as current technology provides techniques that can at best be adjusted only during regular visits to a clinician. Accordingly, various aspects and embodiments are directed to a self-regulating valve and method of operating the same that allows the valve to be automatically adjusted regardless of when and where the patient's needs change.

[0019] According to one embodiment, a method for accurately measuring secondary pressures within a person's brain, such as intraparenchymal venous pressure (Pp), using fully implanted or partially external hardware includes: measuring cerebrospinal fluid pressure (Pcsf) within the ventricles of the brain; indirectly measuring the intraparenchymal pressure (Pp) within the parenchymal space of the brain; calculating the effective pressure difference between the measured pressures Pcsf and Pp (Pei=Pcsf-Pp); and determining whether the measured value of the effective pressure difference represents the true intraparenchymal pressure.

[0020] In one example, if the cerebrospinal fluid pressure measurement (Pcsf) of the ventricle is equal to or within a specified pressure differential threshold relative to the intraparenchymal pressure (Pp) of the parenchymal space of the brain, the pressure of the ventricle of the brain is reduced by a predetermined pressure value. In one example, the specified pressure reduction is 10 mmH2O. The method may further include continuing to reduce the pressure within the ventricle of the brain until the Pcsf pressure measurement is lower than the Pp pressure measurement by the specified pressure differential threshold. In one example, the specified pressure differential threshold is 20 mmH2O. In another example, the Pp measurement represents the true intraparenchymal venous pressure.

[0021] In some examples of the method, the reduction in cerebrospinal fluid pressure treats high-pressure hydrocephalus.

[0022] In some examples of the method, the reduction in cerebrospinal fluid pressure treats normal pressure hydrocephalus.

[0023] In certain examples of the method, the reduction in cerebrospinal fluid pressure treats pseudotumor cerebri condition (idiopathic intracranial hypertension).

[0024] In certain examples of the method, continuous measurement of Pcsf and Pp provides a steady-state balance of ventricular volume and intraparenchymal venous pressure.

[0025] According to another embodiment, a surgically implantable shunt valve system includes: an inflow catheter implanted in a CSF space in a ventricle of the brain or in the spine, the ventricle or CSF space being connected to an inlet port; a shunt valve assembly configured such that when the pressure of the fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow the fluid to be discharged through the orifice into an outlet port; an outflow catheter providing drainage of the fluid from the outlet port to a cavity in the human body capable of absorbing cerebrospinal fluid; a first pressure transducer attached to the inflow catheter for measuring cerebrospinal fluid pressure; a second pressure transducer attached to the inflow catheter for measuring intraparenchymal pressure; and an implantable adjustable valve controller configured to change the valve pressure setting based on measurements from the pressure transducers.

[0026] According to another embodiment, a partially implanted and partially external implantable shunt valve system includes: an implanted inflow catheter that is surgically placed in a CSF space in a ventricle of the brain or in the spine, the ventricle or CSF space connected to an inlet port; an external shunt valve assembly that is configured such that when a pressure of fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow fluid to be discharged through the orifice into an outlet port; an external outflow tube that is connected to an external drainage bag that provides drainage of fluid from the outlet port to a bag outside the body where the bag can be collecting cerebrospinal fluid for analysis and / or treatment; a first pressure transducer attached to the inflow catheter for measuring cerebrospinal fluid pressure; a second pressure transducer attached to the inflow catheter for measuring intraparenchymal pressure; an adjustable valve controller configured to change valve pressure settings based on measurements from the pressure transducers; and an external screen display that displays directly measured CSF and intraparenchymal pressure measurements as instantaneous and trend values ​​in clinically useful values ​​in units of mmH2O, mmHg, etc., and displays other secondary measurements that provide information useful to clinicians.

[0027] In some examples, the first pressure transducer for measuring cerebrospinal fluid pressure (Pcsf) provides a first electrical signal representative of the measured pressure to the valve controller.

[0028] In some examples, the second pressure transducer for measuring intraparenchymal pressure (Pp) provides a second electrical signal representative of the measured pressure to the valve controller.

[0029] In one example, the valve controller calculates the pressure difference between the measured Pcsf and Pp pressures. The valve controller can determine whether the pressure difference between Pcsf and Pp has exceeded a predetermined level. In one example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is less than a predetermined level, the valve controller reduces the pressure setting of the diverter valve assembly by a predetermined value. In one example, the predetermined pressure level is 10 mmH2O. In another example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is greater than a predetermined level, the valve controller identifies the measured Pp pressure as the true Pp pressure.

[0030] According to another embodiment, a surgically implantable shunt valve system includes: an inflow catheter implanted in a ventricle of the brain or in a CSF space in the spine, the ventricle or CSF space connected to an inlet port; a shunt valve assembly configured such that when a pressure of fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow fluid to be discharged through the orifice into an outlet port; and an outflow catheter providing drainage of fluid from the outlet port to a cavity within the body. ; and a first pressure transducer, which is attached to the inflow catheter and is used to measure the intraparenchymal pressure (Pp); a second pressure transducer, which is attached to the inflow catheter and is used to measure the cerebrospinal fluid pressure (Pcsf); and an implantable adjustable valve controller, which is configured to determine whether there is a high-pressure hydrocephalus (HPH), normal-pressure hydrocephalus (NPH) or pseudotumor condition in the brain based on comparing the Pcsf and / or Pp measurements with a predetermined threshold.

[0031] In one example, each time the Pcsf is measured, the first pressure transducer for measuring the intraparenchymal pressure (Pp) provides an electrical signal representative of the measured pressure to the valve controller.

[0032] In one example, the valve controller decreases the pressure setting of the surgically implantable shunt valve assembly by a predetermined value. In another example, the valve controller determines whether the measured Pcsf pressure is less than the measured Pp pressure by a pressure value that is greater than a predetermined amount. In one example, the difference between Pp and Pcsf is greater than 20 mmH2O. In another example, the valve controller maintains the valve pressure setting until the volume of the ventricle of the brain is reduced to a normal volume. In another example, the valve controller increases the pressure setting of the valve assembly until the Pcsf is equal to the Pp.

[0033] According to another embodiment, a surgically implantable shunt valve system includes: an inflow catheter implanted in a CSF space in a ventricle of the brain or in the spine, the ventricle or CSF space being connected to an inlet port; a shunt valve assembly configured such that when the pressure of the fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow fluid to be discharged through the orifice into an outlet port; an outflow catheter providing drainage of fluid from the outlet port to a cavity within the human body; a first pressure transducer attached to the inflow catheter for measuring cerebrospinal fluid pressure; a second pressure transducer attached to the inflow catheter for measuring intraparenchymal pressure; an implantable adjustable valve controller configured to change the valve pressure setting based on measurements from the first pressure transducer and the second pressure transducer; an implantable power source; and a wireless communication mechanism located between the implantable adjustable valve controller and an external programming instrument.

[0034] In one example, the diverter valve assembly includes an implantable adjustable valve separate from the implantable adjustable valve controller. In another example, the implantable adjustable valve is electrically connected to the valve controller via a valve communication cable. In another example, a programmer wirelessly receives operational settings and data from the valve controller. In another example, the programmer wirelessly transmits new values ​​of operational settings to the valve controller.

[0035] In one example, the shunt valve assembly includes an implantable adjustable valve, which is an integrated module in the valve controller. In one example, the adjustable valve is located in a polymer header of the implantable valve controller. In another example, the inflow catheter from the ventricle includes a line for transmitting the pressure values ​​from the first pressure transducer and the second pressure transducer to the implantable valve controller. In one example, the integrated adjustable valve and valve controller are implantable devices separated from the implantable power supply and the wireless communication mechanism. In one example, the shunt valve system further includes a cable, which is connected between the integrated adjustable valve and valve controller and the implantable power supply and the wireless communication mechanism. In one example, the implantable power supply is a primary battery. In another example, the implantable power supply is a rechargeable battery. In one example, the implantable rechargeable battery is charged by an external instrument wirelessly. In one example, the implantable valve controller and the adjustable valve are located proximal to the skull of a human patient. In another example, the implantable valve controller and the adjustable valve receive continuous power wirelessly from a portable external instrument.

[0036] Another embodiment is directed to a method of operating a surgically implantable shunt valve assembly having pressure sensors configured to be implantable, in fluid communication with a ventricle of a brain, and providing pressure data to a valve controller. In one embodiment, the method includes: measuring cerebrospinal fluid pressure (Pcsf) within a ventricle of the brain; measuring intraparenchymal pressure (Pp) within a parenchymal space of the brain; calculating a pressure differential between the measured pressures Pcsf and Pp; and determining whether to adjust a pressure setting of a shunt valve of the surgically implantable shunt valve assembly based on the pressure differential.

[0037] In one example, the Pcsf being greater than a predetermined threshold indicates high-pressure hydrocephalus. In one example, the predetermined pressure difference threshold is 220 mmH2O.

[0038] The method may further include using the valve controller to reduce the pressure setting of the diverter valve by a predetermined decrement. In one example, the predetermined decrement is 10 mmH2O.

[0039] The method may further include determining whether the pressure difference between Pp and Pcsf is greater than a predetermined pressure difference threshold. In one example, the predetermined pressure difference threshold is 10 mmH2O. The method may further include using the valve controller to continue to reduce the shunt valve pressure setting until the pressure difference between Pp and Pcsf is greater than a second predetermined pressure difference threshold. In one example, the second predetermined pressure difference threshold is 20 mmH2O. In one example, the method further includes using the valve controller to maintain the pressure setting until the ventricle returns to normal size or volume. In another example, the method further includes using the valve controller to increase the pressure setting of the shunt valve until Pp and Pcsf are equal. In one example, the method further includes using the valve controller to record Pp and Pcsf values ​​in a memory. In one example, a patient is clinically diagnosed with normal pressure hydrocephalus by a normal Pcsf measurement. In one example, the Pcsf measurement is 150 mmH2O. The method may further include using the valve controller to reduce the pressure setting of the shunt valve by a predetermined decrement. In one example, the predetermined decrement is 10 mmH2O. The method may further include using the valve controller to determine whether the pressure differential between Pp and Pcsf is greater than a predetermined threshold. In one example, the predetermined pressure differential threshold is 10 mmH2O. The method may further include using the valve controller to continue to reduce the shunt valve pressure setting until the pressure differential between Pp and Pcsf is greater than a second predetermined threshold. In one example, the second predetermined pressure differential threshold is 20 mmH2O. The method may further include using the valve controller to maintain the pressure setting until the ventricle returns to normal size or volume. In one example, the method further includes using the valve controller to increase the pressure setting of the shunt valve until Pp and Pcsf are equal. The method may further include using the valve controller to record the Pp and Pcsf values ​​in a memory.

[0040] According to another embodiment, a surgically implantable shunt valve system includes: an inflow catheter implanted in a CSF space in a ventricle of the brain or in the spinal column, the ventricle or CSF space connected to an inlet port; a shunt valve assembly including a shunt valve and configured such that when a pressure of a fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve opens to allow fluid to be discharged through the orifice into an outlet port; an outflow catheter providing drainage of fluid from the outlet port to a cavity within the human body; a first pressure transducer attached to the inflow catheter tube for measuring cerebrospinal fluid pressure; a second pressure transducer, which is attached to the inflow catheter and is used to measure intraparenchymal pressure; an implantable adjustable valve controller, which is configured to change the valve pressure setting based on the measurements from the first pressure transducer and the second pressure transducer; an implantable power source; a first wireless communication device, which is configured to provide wireless communication between an external programming instrument and the implantable valve controller; and a second wireless communication device, which is configured to provide wireless communication between the implantable valve controller and an external patient receiver.

[0041] In one example, the implantable valve controller provides wireless data transmission to the external patient receiver. In one example, the data to be transmitted includes measured pressure signals from the first pressure transducer and the second pressure transducer. In another example, the data to be transmitted includes alarm data. The alarm data may indicate that the pressure measurement values ​​obtained from the first pressure transducer and the second pressure transducer are abnormal. In one example, the alarm data indicates a device system failure. In one example, the external patient receiver provides an audio alarm to the patient. In another example, the external patient receiver provides a visual alarm to the patient. In some examples, the valve controller wirelessly transmits all measurement data to the external patient receiver after the alarm signal is transmitted.

[0042] According to another embodiment, a shunt valve system includes: an inflow catheter implanted in a CSF space in a ventricle of the brain or in the spinal column, the ventricle or CSF space being connected to an inlet port; a shunt valve assembly configured such that when the pressure of the fluid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow the fluid to be discharged through the orifice into an outlet port; an outflow catheter providing drainage of the fluid from the outlet port to an external ventricular drainage system; a first pressure transducer attached to the inflow catheter for measuring cerebrospinal fluid pressure; a second pressure transducer attached to the inflow catheter for measuring intraparenchymal pressure; and an adjustable valve controller configured to change the valve pressure setting based on measurements from the pressure transducers.

[0043] In one example, the first pressure transducer for measuring cerebrospinal fluid pressure (Pcsf) provides a first electrical signal representing the measured pressure to the valve controller. In another example, the second pressure transducer for measuring intraparenchymal pressure (Pp) provides a second electrical signal representing the measured pressure to the valve controller. In one example, the valve controller calculates the pressure difference between the measured Pcsf and Pp pressures. In another example, the valve controller determines whether the pressure difference between the Pcsf and the Pp has exceeded a predetermined level. In one example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is less than a predetermined level, the valve controller reduces the pressure setting of the diverter valve assembly by a predetermined value. In one example, the predetermined pressure level is 10 mmH2O. In another example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is greater than a predetermined level, the valve controller identifies the measured Pp pressure as the true Pp pressure.

[0044] According to another embodiment, a shunt valve system includes: an inflow catheter implanted in a CSF space in a ventricle of the brain or in the spinal column, the ventricle or CSF space being connected to an inlet port; a shunt valve assembly configured such that when the pressure of the liquid in the inlet port exceeds a selected pressure setting of the shunt valve assembly, an orifice of the shunt valve assembly opens to allow the liquid to be discharged through the orifice into an outlet port; an outflow catheter providing drainage of the liquid from the outlet port to a cavity in the human body capable of absorbing cerebrospinal fluid; a differential pressure transducer attached to the inflow catheter and configured to measure cerebrospinal fluid pressure (Pcsf) and intraparenchymal pressure (Pp); and an adjustable valve controller configured to calculate the pressure difference between the measured cerebrospinal fluid pressure and the intraparenchymal pressure and to change the valve pressure setting based on the measurement value from the differential pressure transducer.

[0045] In one example, the differential pressure transducer includes a first pressure transducer for measuring the cerebrospinal fluid pressure and a second pressure transducer for measuring the intraparenchymal pressure.

[0046] In one example, the valve controller is further configured to determine whether the pressure difference between the Pcsf and the Pp has exceeded a predetermined level. In one example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is less than the predetermined level, the valve controller reduces the pressure setting of the diverter valve assembly by a predetermined value. For example, the predetermined pressure level may be 10 mmH2O. In another example, if the valve controller determines that the pressure difference between the Pcsf and the Pp is greater than a predetermined level, the valve controller identifies the measured Pp pressure as the true Pp pressure.

[0047] Another embodiment is directed to a method of operating a diverter valve assembly having pressure sensors configured to be in fluid communication with a ventricle of a brain to provide pressure data to a valve controller. In one embodiment, the method includes: measuring cerebrospinal fluid pressure (Pcsf) within a ventricle of the brain; measuring intraparenchymal pressure (Pp) within a parenchymal space of the brain; calculating a pressure differential between the measured pressures Pcsf and Pp; and determining whether to adjust a pressure setting of a diverter valve of the diverter valve assembly based on the pressure differential.

[0048] Other aspects, embodiments, and advantages of these exemplary aspects and embodiments are discussed in detail below. The embodiments disclosed herein may be combined with other embodiments in any manner consistent with at least one of the principles disclosed herein, and references to "embodiments," "some embodiments," "alternative embodiments," "various embodiments," "one embodiment," etc. are not necessarily mutually exclusive and are intended to indicate that the particular features, structures, or characteristics being described may be included in at least one embodiment. These terms appearing herein do not necessarily all refer to the same embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Various aspects of the embodiments are discussed below with respect to the accompanying drawings. For clarity, not every component may be labeled in every drawing. The drawings are not necessarily to scale; emphasis is instead placed on illustrating the principles of the invention. The drawings are included to provide illustration and further understanding of the various aspects and embodiments, and are incorporated in and constitute a part of this specification but are not intended to be a limitation of the invention. In the drawings:

[0050] Figure 1 is a diagram showing the anatomy of the human brain presented in a spherical model with reference to various structures and associated pressure measurements;

[0051] Figure 2AIt is a graphical representation of the algorithm for the physician to perform clinical evaluation of the self-adjustable valve for various clinical conditions;

[0052] Figure 2B is a graphical representation of an algorithm for measuring and treating using a self-adjustable valve in a patient diagnosed with hydrocephalus;

[0053] Figure 2C is an illustration of an example of laboratory research data for pressure measurements and a graphical representation of the pressure measurements described herein;

[0054] Figure 3A is a diagram showing device components of an example of a self-regulating hydrocephalus valve system based on a mechanical design approach;

[0055] Figure 3B is a diagram showing device components of an example of a self-regulating hydrocephalus valve system;

[0056] Figure 3C is a diagram illustrating another example of device components of a self-regulating hydrocephalus valve system, the self-regulating hydrocephalus valve system also including a portable wireless receiving device;

[0057] Figure 4 is a diagram showing a configuration of device components providing another example of a self-regulating hydrocephalus valve system with an integrated controller and adjustable valve;

[0058] Figure 5 is a diagram showing a configuration of components of a device providing another example of a self-regulating hydrocephalus valve system having an integrated controller and adjustable valve and having a rechargeable power source;

[0059] Figure 6 is a flow chart of an example of measurement and monitoring of CSF pressure (Pcsf) and intraparenchymal venous pressure (Pp) in determining the presence of a hydrocephalic condition;

[0060] Figure 7 is a flow chart of an example of a treatment algorithm during steady-state operation;

[0061] Figure 8 is an electronic block diagram of an example of an implantable valve controller and external instrumentation;

[0062] Fig.9A It is used to show Figure 6 A graphical representation of a time-based pressure measurement of the algorithm presented in the flowchart;

[0063] Fig. 9B is a graphic showing the steps to follow in the treatment example of high-pressure hydrocephalus; and

[0064] Fig. 9Cis a graphic showing the steps followed in the treatment example of normal pressure hydrocephalus. DETAILED DESCRIPTION

[0065] Various aspects and embodiments are directed to a self-regulating valve configured to be implanted in a patient or connected to a catheter implanted in a patient and used to regulate the flow (drainage) of cerebrospinal fluid (CSF).

[0066] definition:

[0067] Arachnoid villi: microscopic projections of the arachnoid membrane into the venous sinuses through which CSF drains into the bloodstream.

[0068] Atrium: One of the two upper chambers of the heart where blood enters.

[0069] Catheter: A thin tube made of medical grade material used to divert fluids.

[0070] The catheter is the distal outflow tube of the atrium that drains the atria to the shunt in the atrium.

[0071] Catheter, Drainage: The distal outflow catheter (tube) of a shunt; the tube through which fluid leaves the shunt valve system.

[0072] Catheter, Inflow: The proximal tube of a shunt that is placed in one of the CSF compartments through which CSF flows into the shunt valve system.

[0073] Catheter, Lumbar: The proximal tube of the shunt through which CSF is drained from the CSF spaces surrounding the spinal column.

[0074] Catheter, peritoneal: The distal outflow tube of a shunt that drains into the peritoneum.

[0075] Catheter, ventricular: The proximal inflow tube of a shunt that drains CSF from the ventricles of the brain.

[0076] Cerebrospinal fluid: A clear, colorless fluid that bathes the brain and spinal cord and is produced primarily in the choroid plexuses of the cerebral ventricles. It acts as a buffer or dampener for the brain and provides essential mechanical and immunological protection for the brain within the skull and vertebral columns.

[0077] Choroid Plexus: The choroid plexus is a cluster of cells that produces most of the cerebrospinal fluid in the ventricles of the brain. The choroid plexus is composed of modified ependymal cells.

[0078] External Drainage System (EDS) External drainage and monitoring is accomplished by temporarily draining CSF from the lateral ventricles of the brain or the lumbar space of the spine into an external collection bag using a combination of gravity and CSF pressure.

[0079] External Lumbar Drain System External Drain and Monitor is a system that temporarily drains CSF from the lumbar space of the spine into an external collection bag using a combination of gravity and CSF pressure (ELDS).

[0080] External ventricular drain systems External drain and monitoring are used to temporarily drain CSF from the lateral ventricles of the brain into external collection bags using a combination of gravity and CSF pressure (EVDS).

[0081] Fixed Pressure Valves that operate at a single operating pressure.

[0082] Hydrocephalus: A condition associated with an enlargement of the volume of the cerebral ventricles caused by a net accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain.

[0083] Hydrocephalus, communicating: Nonobstructive hydrocephalus; a form of hydrocephalus that is not caused by visible obstruction to CSF ​​flow.

[0084] Hydrocephalus, High Pressure: High-pressure hydrocephalus; a neurological disorder in which excessive CSF accumulates within the ventricles of the brain. The buildup of CSF causes increased pressure inside the brain (skull), causing the ventricles to expand in size and brain tissue to stretch, putting pressure on critical structures.

[0085] Hydrocephalus, nonobstructive: See communicating hydrocephalus.

[0086] Hydrocephalus, Normal Pressure: Abbreviated as NPH, this condition is a buildup of CSF that causes enlargement of the brain's ventricles, sometimes with little or no increase in ICP, in which a triad (a set of three) of neurological symptoms occur in the presence of "normal" CSF pressure - gait disturbance (usually the first to appear), dementia, and impaired bladder control. Depending on severity, one or more of these symptoms may be present.

[0087] Hydrocephalus, obstructive: See high-pressure hydrocephalus.

[0088] Lumbar peritoneal shunt: A shunt valve system used to divert CSF from the subarachnoid (lumbar sheath) space in the lower back to the abdominal cavity.

[0089] Parenchyma, cerebrum: The functional tissue of the brain composed of two types of brain cells: neurons and glial cells.

[0090] Peritoneum: The serous membrane that lines the abdominal cavity and covers the abdominal organs.

[0091] Pressure, Subarachnoid: CSF pressure measured in the subarachnoid CSF space.

[0092] Pressure, Subdural: Pressure measured in the subdural space.

[0093] Programmable Pressure: Variable pressure valve mechanism whose non-invasively adjustable operating pressure range can be changed by a programmer.

[0094] Shunt: An implantable device that typically consists of two conduits (inflow and outflow) and a one-way valve that regulates the amount, direction, and pressure of CSF in the brain fluid compartment.

[0095] Sinus, Superior Sagittal: The superior longitudinal sinus within the human skull; an unpaired area along the attachment margin of the falx cerebri that allows blood to drain from the lateral aspect of the anterior cerebral hemisphere to the confluence of the sinus.

[0096] Space, Lumbar Sheath: The CSF fluid compartment is surrounded by the thecal sac or dural sac; a membrane sheath of the dura mater that surrounds the spinal cord and cauda equina. The thecal sac contains the cerebrospinal fluid in which the spinal cord "floats".

[0097] Space, subarachnoid space: The interval between the arachnoid and pia mater, occupied by delicate connective tissue trabeculae and interconnected channels containing CSF.

[0098] Valve: A resistance-adjusting mechanism in a shunt that allows fluid to flow in one direction only. Classically, valves can be fixed pressure or non-invasively adjustable pressure.

[0099] Vein, jugular: The vein in the neck that carries blood from the head to the superior vena cava (the major vein in the upper body) and then to the heart.

[0100] Veins, superficial cerebral: A group of cerebral veins in the head that includes the superior cerebral vein, the superficial middle cerebral vein, the inferior cerebral vein, the inferior anastomotic vein, and the superior anastomotic vein.

[0101] Ventricle(s): The cavities in the brain lined with ependymal cells in which CSF is produced and then circulates around the cranial cavity, communicating with the subarachnoid space(s) of the spinal cord or draining into the arachnoid villi. The ventricles include the paired lateral ventricles, which drain into the third ventricle and then into the fourth ventricle.

[0102] Ventricular-atrial shunt: A shunt valve system that moves (diverts) fluid from the ventricles of the brain to the right atrium of the heart.

[0103] Ventriculoperitoneal shunt: A shunt valve system that moves (diverts) fluid from the ventricles of the brain to the abdominal cavity.

[0104] abbreviation:

[0105] CSF: cerebrospinal fluid

[0106] EDS External Drainage System

[0107] ELDS External Lumbar Drainage System

[0108] EVDS External ventricular drainage system

[0109] HPH: High Pressure Hydrocephalus

[0110] NPH: Normal Pressure Hydrocephalus

[0111] Pcsf: intraventricular CSF pressure

[0112] Pei: Effective intraventricular CSF pressure difference Pei=Pcsf-Pp

[0113] Pp: intraparenchymal venous pressure

[0114] Psa: subarachnoid space pressure

[0115] Pv: extraparenchymal venous pressure (measured at the superior sagittal sinus (SSS))

[0116] Pvalve: Valve operating pressure

[0117] SSS: Superior sagittal sinus

[0118] HPH and NPH develop through the interaction between different fluid pressures within the central nervous system.

[0119] like Figure 1 As shown, the superficial cerebral veins 105, which emerge from the brain surface and drain blood from the brain parenchyma sponge, travel through the subarachnoid space 115, which is bathed in cerebrospinal fluid (CSF), to join the dural venous sinuses and drain into the superior sagittal sinus (SSS) 130. In the horizontal position, the normal pressure in the SSS 130 is about 70 mm H2O (Pv = extraparenchymal venous pressure measured in the SSS).

[0120] The CSF also drains into the SSS 130, but through a different route, namely the arachnoid villi 135 in the wall of the SSS. The CSF pressure is the result of the resistance across these arachnoid villi 135 plus the pressure of the SSS 130. Thus, the normal pressure of the CSF in the subarachnoid space 115 (Psa = subarachnoid CSF pressure) is typically 120 mmH2O when the patient is in a horizontal position. The subarachnoid CSF pressure causes parallel changes in the pressure of the intraparenchymal venous system. Likewise, changes in venous pressure at the level of the SSS 130 or behind it are equally transmitted to the intraparenchymal venous and CSF systems, since both drain into the SSS 130. These two mechanisms ensure a constant hydrostatic load of the brain tissue or spongy parenchyma 125.

[0121] The brain tissue or parenchyma 125 is subjected to two opposing pressures. One pressure is generated by the CSF system (Pcsf), which tends to expand the ventricles 110 (and decrease the volume of the parenchyma 125; i.e., decrease the volume of the sponge). The other pressure is generated by the intraparenchymal venous system 120 (Pp), which tends to oppose the expansion of the ventricular volume and decrease the ventricular volume (and increase the volume of the parenchyma 125). As long as these two pressures remain equal regardless of their absolute values, the pressure difference between them is zero, and the tissue is not subjected to a slight degree of stress or deformation; the ventricular volume and the parenchymal volume remain unchanged and in a steady-state condition.

[0122] The gradient that allows the control fluid to be extruded or infused into the parenchymal sponge and thus change and control the ventricular volume and produce a specific form of hydrocephalus is the difference that exists between the intracerebroventricular CSF pressure (Pcsf) and the intraparenchymal venous pressure (Pp). This gradient is designated as the effective intracerebroventricular CSF pressure difference (Pei = Pcsf - Pp). When Pcsf > Pp, then Pei > 0, and fluid is extruded from the parenchyma 125 (i.e., the sponge is "squeezed"), and the ventricular volume increases. Conversely, when Pcsf < Pp, then Pei < 0, and fluid is allowed to fill the parenchyma 125 and expand the parenchymal volume, and the ventricular volume decreases. NPH symptoms occur when the ventricular volume expansion is not offset by an equal Pp and ventricular dilation occurs (even at normal Pcsf).

[0123] In a normal brain 100, the cerebrospinal fluid pressure (Pcsf) 110 within the ventricles typically equals the pressure (Pp) of the intraparenchymal venous pathway 120. Thus, when Pcsf = Pp, there is no gradient between these two pressure compartments that would cause ventricular expansion, the ventricular volume remains normal, and hydrocephalus does not occur. Hydrocephalus or an expansion of the ventricular cavity volume in the brain 100 is produced by a pressure imbalance in the brain 100 (i.e., the gradient between Pcsf and Pp) and can occur when Pcsf 110 is greater than Pp 120 (as in the case of high-pressure hydrocephalus) or when Pp 120 is less than Pcsf 110 (as in the case of normal-pressure hydrocephalus). The goal of hydrocephalus management is to manipulate the CSF pressure (Pcsf) such that it is lower than or equal to the parenchymal pressure (Pp).

[0124] Early shunts (consisting of an inflow catheter, a valve, and a drainage catheter) for treating hydrocephalus incorporated a fixed pressure valve to regulate the flow through the shunt. In many cases, after implantation of a fixed pressure valve, due to insufficient or excessive drainage, and one of the different operating pressure ranges (e.g., a lower pressure range for insufficient drainage or a higher pressure range for excessive drainage), the physician will need to perform several surgeries to replace the initial valve until the optimal operating pressure range (balanced condition) is determined. Externally (non-invasively) adjustable, "programmable" valves have been developed, in which the operating pressure of the valve can be adjusted non-invasively (through the skin) instead of using surgery to replace the valve. However, it is usually necessary to frequently adjust the pressure setting of such a programmable valve to optimize the shunt performance. This is achieved through one or more visits to the clinician. After programming, the adjustable valve acts like a fixed pressure valve (i.e., not adjusted for the patient's changing requirements) until it is reprogrammed according to the clinician's clinical judgment. This limits the times when such valves can be adjusted to the needs of a patient visit and does not allow for adaptation of the patient's daily requirements through valve adjustment according to the patient's changing clinical needs throughout the day.

[0125] Aspects and embodiments are directed to a self-regulating valve that can continuously determine desired valve resistance and adjust accordingly without intervention by a clinician.

[0126] Conventional shunt valves in use today, whether fixed pressure valves or non-invasively adjustable valves, operate using two parameters: inlet pressure (CSF) and outlet drainage pressure (either the right atrium of the heart (essentially zero pressure) or peritoneal cavity pressure). These devices control the CSF pressure, allowing CSF to flow through the valve until the pressure of the CSF drops to a pressure below the operating pressure setting of the valve system. Even though a physician can use some parameters (such as ventricular volume and CSF pressure) as a guide for setting the valve operating pressure, there is some trial and error involved in valve selection (fixed pressure valves) or adjustment (variable pressure valves). In contrast, various aspects and embodiments are directed to self-regulating valves that use a third parameter that provides feedback to automatically control the adjustment of the valve's pressure setting and thereby provide a closed-loop system to autonomously and continuously adjust the valve at any time and anywhere without the need for clinician intervention.

[0127] Based on earlier understanding of the brain, in healthy patients, the subdural pressure value is zero because the brain tissue absorbs the CSF pressure from the ventricles. As a patient develops hydrocephalus and the volume of the ventricles increases and / or the value of the CSF pressure increases, more ventricular pressure will be transmitted through the brain tissue or parenchyma to the brain surface, and the subdural pressure will have a positive value. Conventional self-regulating valves are based on the concept that the subdural pressure in a normal person is equal to zero. Only when a person develops hydrocephalus will the value of the subdural pressure be higher than zero, and this will be used to lower the pressure setting of the valve to drain CSF.

[0128] According to some aspects, it can be concluded from a more recent understanding of the hydrodynamics of the cranial cavity and experimental evidence that the subdural pressure in healthy subjects will not be zero. Instead, the subdural sensor will measure the higher of two pressures: Pcsf and Pp. Thus, aspects and embodiments of the self-regulating valve are at least partially based on the recognition that the parenchymal pressure sensor measures the higher of the intraparenchymal venous pressure (Pp) and the intraventricular CSF pressure (Pcsf). A sensor placed in the CSF can be used to directly measure Pcsf. Thus, by comparing the pressure readings of the subdural sensor probe with the pressure readings from the CSF pressure sensor, an observer or system can extrapolate Pp.

[0129] More specifically, in the starting state, a patient with high-pressure hydrocephalus (HPH) has a high Pcsf and a normal Pp (i.e., Pcsf > Pp). At the starting point, the parenchymal sensor measures Pcsf because Pcsf is higher than Pp. The CSF pressure sensor, which also measures Pcsf, can give the same reading as the parenchymal sensor. The valve can then be set to allow the patient's Pcsf to slowly decrease. As Pcsf begins to decrease, the parenchymal sensor and the CSF sensor will continue to give the same reading. However, once the patient's Pcsf drops below Pp, the parenchymal sensor will begin to measure Pp instead. At this point, the system or observer can know that Pcsf < Pp because the parenchymal sensor and the CSF sensor are measuring different pressure readings. The valve can be kept at this setting long enough to allow the ventricles to normalize (i.e., drain to a physiologically normal volume). The valve can then be adjusted to make Pcsf and Pp equal to maintain a steady-state balance. As further discussed below, the aspects and embodiments disclosed herein provide systems and methods for equalizing Pcsf and Pp, thereby correcting the pressure imbalance that causes ventricular volume expansion and thus treating patients with HPH or NPH.

[0130] Certain aspects are also based, at least in part, on the recognition that normal pressure hydrocephalus (NPH) is characterized by a pressure imbalance in the brain, with a normal Pcsf and a lower than normal Pp (i.e., Pcsf>Pp). Various aspects and embodiments disclosed herein provide systems and methods for equalizing Pcsf and Pp, thereby correcting the pressure imbalance that causes the volume of the ventricles to expand at normal Pcsf pressures and thereby treating patients with NPH. The following table summarizes these pressure relationship concepts for non-hydrocephalus conditions, HPH, and NPH:

[0131]

[0132]

[0133] Advantageously, some patients recover significantly even though the size of the ventricles has not been reduced much. In some cases, simply reducing the pressure gradient that produces the enlarged ventricles may be sufficient to allow the patient to recover. In other words, it may not be entirely necessary for the ventricles to be reduced to a normal volume in order for the patient to recover. Therefore, certain aspects are primarily concerned with reducing the pressure gradient between Pcsf and Pp.

[0134] For patients with high pressure hydrocephalus (HPH), Pcsf 110 is higher than normal (due to partial obstruction in the CSF circulation) and Pp 120 is normal, therefore Pcsf>Pp. For patients with normal pressure hydrocephalus (NPH), Pcsf 110 is normal (because there is no obstruction in the CSF circulation), but Pp 120 is lower than normal; therefore: Pcsf>Pp.

[0135] Figure 2AA graphical representation of a process is provided by which a physician can visually assess the patient's ventricular volume status by clinical means (e.g., imaging) to determine if a hydrocephalus condition exists. Visual imaging assessments can be accomplished, for example, by MRI or CT scans. If the clinical evaluation indicates ventricular enlargement associated with hydrocephalus, the valve pressure setting can be lowered to reduce the ventricular volume. The hydrocephalus condition can be assessed as high-pressure hydrocephalus (HPH) or normal-pressure hydrocephalus (NPH). The manual adjustment is the same for both conditions. If the ventricular volume is determined to be normal size, the hydrocephalus control system can measure the Pcsf and Pp pressures and can be programmed to a "standby" steady-state mode that monitors CSF pressure and intraparenchymal venous pressure as the hydrocephalus will be in a stagnant state. However, a normal ventricular volume with high Pcsf and high Pp can indicate a pseudotumor condition. In this case, the valve pressure can be lowered to allow Pcsf and Pp to decrease to normal values. If the assessment indicates that the ventricles are in a "fissured" condition (called fissured or smaller than normal ventricles), the valve pressure setting can be increased to allow the ventricle volume to expand ("normalize"). The ventricle volume can be monitored visually to assess whether the ventricles are returning to normal size.

[0136] Figure 2B A graphical representation of an algorithm for a self-adjustable valve is provided. Step 1 shows that there may be electronic sensors (i.e., pressure sensors) that can measure intraventricular CSF pressure (Pcsf) and intraparenchymal venous pressure (Pp). The Pcsf and Pp pressure measurements can be compared to determine whether they can be equal, or whether Pcsf can be greater than or equal to Pp, or whether Pcsf can be lower than Pp. If Pcsf is not lower than Pp (step 2), the Pp measurement may not yet be the actual extraparenchymal venous pressure (Pv). The valve pressure setting can be reduced in a closed-loop algorithm that changes the valve pressure setting, waits for a set time period, and measures the two pressures until Pcsf is lower than Pp. Once Pcsf is lower than Pp (step 3), it can be assumed that Pp can reflect the actual extraparenchymal venous pressure (Pv).

[0137] Figure 2CEvidence examples are provided based on research data that sensors implanted in the subdural region of the cranial cavity measure the higher of the intraparenchymal venous pressure (Pp) and the cerebrospinal fluid pressure (Pcsf). In healthy subjects, these two pressures are typically equal. In contrast, in HPH, NPH or pseudotumors (conditions where intracranial pressure increases and the ventricles are not enlarged), the sensors in the subdural region may not necessarily measure the intraparenchymal venous pressure. Sensors, transducers or other devices used to measure specific variable pressures in the cranial cavity tend to measure all other variables in the environment to some extent, and therefore will measure the highest pressure in different liquids. In the three conditions mentioned above (i.e. HPH, NPH or pseudotumors), if this is the higher pressure of Pp and Pcsf, the sensors in the subdural region only directly measure the intraparenchymal venous pressure (Pp).

[0138]

[0139]

[0140] It can be concluded that the measured pressure is always the higher of the two pressures. Therefore, certain aspects relate to methods for independently measuring Pp and Pcsf. Based on the assumption that under normal conditions CSF pressure controls intraparenchymal venous pressure, the following experiment was designed, and Figure 2C The graphs in show the results.

[0141] Simultaneous measurements were performed in normal dogs for:

[0142] Ventricular CSF pressure (graph indicated by circular markers)

[0143] Subdural pressure (graph indicated by square markers)

[0144] Superior sagittal sinus pressure (graph indicated by the triangle marker)

[0145] As the pressure is recorded, the ventricular CSF pressure is slowly reduced by lowering the bag connected to the ventricle and filled with saline solution (graph with circular marks). It is observed that as the ventricular CSF pressure (Pcsf) decreases, this produces an equal pressure reduction at the subdural sensor (graph with square marks). As seen from the left portion of the graph, the two pressures continue to decrease until they reach the value of the superior sagittal sinus pressure (graph with triangle marks), at which time Pcsf continues to decrease, but the subdural pressure does not decrease further (i.e., it is lower than Pv in SSS). At this point, the subdural sensor is now measuring the intraparenchymal venous pressure (Pp), which cannot be lower than the value of the superior sagittal sinus pressure (abbreviated as Pv, and Pv=Pp in the central portion of the graph). In the central portion of the graph, Pcsf is lower than Pp, and the subdural sensor measures Pp. Later, as the ventricular CSF pressure is increased by raising the bag filled with saline, the intraparenchymal venous pressure measured by the subdural sensor starts to increase only when the CSF pressure is above the value of the superior sagittal sinus pressure (Pv) (as shown in the right part of the graph).

[0146] like Figure 2A and Figure 2B The basic principle of true measurement of intraparenchymal venous pressure as presented in and described further below can be implemented as a mechanical regulation system or as a sensor-based electronic regulation control system. Figure 3A An example of a mechanically designed self-regulating valve is shown. The hydrocephalus adjustable valve 310 may include a ventricular catheter 340 that may be implanted in a ventricle of the brain that may provide a Pcsf measurement. The pressure that may also be used as feedback to the mechanically controlled hydrocephalus valve system may be the contact pressure at the surface of the brain (as exemplified by a subdural pressure bag 305). The self-regulating valve 310 may mechanically reduce pressure in an attempt to maintain an equality between Pcsf and the subdural pressure. The adjustable valve 310 may also be connected to a distal outflow drainage catheter 390 and located outside the skull.

[0147] Figure 3BThe device components of the example of adjustable hydrocephalus valve system 300 are shown. As discussed above, the hydrocephalus adjustable valve 310 can include a ventricular catheter 340, which can be implanted in the ventricle of the brain. In some examples, the ventricular catheter 340 can be connected to or be a part of an external ventricular drainage system, which is used to control the drainage of CSF from the subarachnoid space of the brain or spinal cord, with a display of sensor output and data processing to provide physiological related data. An electronic CSF pressure sensor 330 can be mounted on the outer surface of the ventricular catheter 340, and can be able to measure the CSF pressure (Pcsf) in the liquid space. A second electronic pressure sensor 320 can also be installed on the ventricular catheter 340 externally at a position in contact with the brain substance, and can be able to indirectly measure the intraparenchymal venous pressure (Pp). The adjustable valve 310 can be connected to a distal outflow drainage catheter 390 and is located outside the skull. The second catheter or valve communication cable 350 may include a CSF pressure (Pcsf) sensor 330, an intraparenchymal venous pressure (Pp) sensor 320, and electrical connections or lines for electronic control signals to change the pressure setting of the adjustable valve 310. The valve communication cable 350 may also be connected to a valve controller 360, which may include an implantable electronic valve control device and a power source, and may provide information upon which valve adjustments are based.

[0148] According to certain embodiments, the valve controller 360 may include a power supply, a microcontroller, and wireless communication circuitry ( Figure 3B ), and are referred to below Figure 8 The power source may be a primary battery, a rechargeable battery, or a device that can receive continuous wireless power transmission from an external power source (or may be a combination of two or more of these elements). A microcontroller within valve controller 360 may analyze the pressure measurements obtained by the two pressure sensors and may determine, based on each measurement, an action to be taken to change the setting of adjustable valve 310. Examples of these algorithms are referenced in Figure 6360 . The wireless communications can provide the clinician with the ability to retrieve stored, recorded pressure measurements, command the implantable valve controller 360 to perform a specified operation, retrieve the currently programmed operating settings of the valve controller 360, and reprogram (adjust) the operating settings of the adjustable valve 310 and the implantable valve controller 360. As is typical for active implantable medical devices, the electronics of the valve controller 360 can be enclosed in a sealed housing (made of titanium or a similar material). The external programmer 380 can provide a graphical user interface for viewing information retrieved from the implantable valve controller 360. In addition, the external programmer 380 can provide transcutaneous wireless communications that can retrieve data from the valve controller 360 via a programming wand 370, which can receive the wirelessly transmitted data for viewing and archiving by the physician, and transmit the programmed data to allow the physician to adjust the operating settings in the valve controller 360 to control the adjustable valve 310.

[0149] Figure 3C Variations of system components are available. Figure 3C In the example shown, all parts are Figure 3B , except that there may be an additional external device or patient wireless receiver 375 that may be carried by the patient or caregiver. The patient wireless receiver 375 may receive wireless communications from the implanted valve controller 360. For example, wireless communications may be initiated by the valve controller 360 and sent to the patient wireless receiver 375 as a result of an alarm condition identified by the valve controller 360. The alarm condition may be a result of pressure measurements from the CSF pressure (Pcsf) sensor 330, the intraparenchymal pressure (Pp) sensor 320, and / or the intraventricular CSF pressure differential (Pei=Pcsf-Pp). An alarm may also be generated as a result of a condition identified by the valve controller 360 during a self-diagnostic check of the implanted system.

[0150] According to another embodiment, an example is shown in Figure 4 As shown in FIG. 4 , the self-regulating hydrocephalus valve system 400 includes an adjustable valve 410 and a valve controller 460 that can be integrated and physically assembled into an implantable self-regulating valve / controller device 470. Figure 3B, the electronics of the valve controller 460 can be enclosed in a sealed titanium housing. The adjustable valve 410 can be enclosed in a polymer manifold 415. The drainage catheter 480 can leave the adjustable valve 410 through the polymer manifold 415. The self-regulating valve / controller device 470 can also allow for simpler ventricular catheters 440, as well as line connections between the intraventricular CSF pressure sensor 430 and the intraparenchymal venous pressure sensor 420 and the adjustable valve 410, as a single ventricular or lumbar catheter and pressure sensor line 450. The electrical connections between the valve controller 460 and the adjustable valve 410 can be contained within the self-regulating valve / controller device 470.

[0151] Another embodiment of the self-regulating hydrocephalus valve system 500 is Figure 5 . In this example, the self-regulating valve / controller device 560 can still be integrated, but the power supply and wireless communication can be configured as separate modules 540. This configuration can provide the advantages of a smaller self-regulating valve / controller device 560, resulting in a shorter drainage catheter and sensor line to the self-regulating valve / controller device 560. The power supply in this embodiment can also include a rechargeable battery, which provides a longer implantation duration and / or the option of a smaller battery. The implantable wireless communication and rechargeable power supply 540 can be located away from the self-regulating valve / controller device 560. Wireless power transmission between the external battery charger 520 and the wireless communication and rechargeable power supply 540 can transmit power from the power supply coil 522 to the coil within the wireless communication and rechargeable power supply 540. Power for charging the wireless communication and rechargeable power supply 540 can be provided by a portable (e.g., patient-wearable) battery and power control 524 device, or the power can be provided from an AC adapter (not shown).

[0152] like Figure 6 The flowchart in FIG. 1 shows an example of a process for determining the recurrence of hydrocephalus during steady-state monitoring at predetermined intervals. Figure 3B 10 and the intraparenchymal venous pressure (Pp) 120. The monitoring process can also allow the valve controller 360 to record and identify changes in Pcsf throughout the day (or other time period) to take into account the patient's circadian rhythm and the patient's changing posture as parameters when determining whether a potential hydrocephalus condition may exist.

[0153] Reference Figure 6, in step 600, a process encoded in the valve controller 360 may be initiated by obtaining a pressure measurement from the CSF pressure (Pcsf) sensor 330. The Pcsf measured value may be compared to a predetermined Pcsf value, and the process may include a step 605 of identifying whether the measured Pcsf is within a predetermined normal range for the patient, such as stored in a memory of the valve controller 360. If the Pcsf is within the normal range for Pcsf, step 610 may include determining whether the Pcsf is within an acceptable pressure differential (or Δ) of the previously measured Pp. If the pressure Δ is within the normal range for Pp, the Pcsf may be factored into a moving average calculation in step 650 to account for changes in Pcsf throughout the day. The process may then wait for a programmed Pcsf measurement delay period 655 (e.g., 1 hour) before taking the next Pcsf measurement 600. If it is determined in step 605 that the Pcsf value is not within the normal Pcsf range for the patient, step 620 may include determining whether there is a sufficient time interval (e.g., 3 hours) since the last Pp measurement. The process may also include performing multiple sequential measurements of Pcsf (not shown in the flowchart) to verify that the increased pressure difference of Pp is not caused by abnormal measurements (e.g., noise). In the case where the Pp measurement interval is longer than the Pcsf measurement interval, the verification of Pcsf at this longer interval in step 620 can provide the measurement process with the ability to confirm that Pcsf may be out of range. Similar to the Pcsf measurement, confirmation by repeated measurements can filter out any measurement noise artifacts before the Pp measurement is performed. Repeated measurements to confirm valid pressure values ​​may also be applicable to other conditions in the entire process when it is suspected that significant pressure deviations may potentially occur. If the Pp measurement interval has not been reached in step 620, the Pcsf measurement value can be factored into the moving average calculation in step 625, and the process can then wait for a specified Pcsf measurement delay period 630 before making the next Pcsf measurement in step 600. If the Pp measurement interval has been reached in step 620, Pp can be measured in step 635. Figure 7An example of a method for determining whether the measurement from the Pp sensor 330 is representative of the actual intraparenchymal venous pressure is further discussed. If it is determined in step 640 that Pp is within the acceptable Δ limit of Pcsf, a normal non-hydrocephalus condition can be identified and the Pp measurement can be calculated as a Pp moving average 645. The process can then proceed to step 655 to wait for the next Pcsf measurement delay. If the Pp measurement is not within the acceptable Δ of Pcsf 640, the valve controller 360 can record the Pp value in step 615 and the condition can be identified as hydrocephalus, and the patient can be alerted via wireless communication, and then proceed to the treatment process. The physician can also program the valve controller 360 to only provide the patient with an alert of a pressure measurement deviation and instructions to contact their physician. The measured data can be transmitted remotely to the physician for review. The physician can remotely reprogram the valve controller 360, or request that the patient go to a medical facility (hospital office) for further clinical evaluation, as described above with reference to Figure 2A described to determine whether the hydrocephalus condition has resolved.

[0154] Once the patient has returned to a non-hydrocephalic condition (i.e., normalization of the ventricles), the physician can identify this by continuously monitoring and recording the mean pressure and its minimum and maximum ranges indicative of the patient's daily circadian rhythm. According to certain embodiments, the primary purpose of the valve controller 360 is to maintain the same pressure gradient between Pcsf and Pp throughout the day and to maintain changes associated with changes in the patient's body position (posture).

[0155] According to one embodiment, to initially program the adjustable valve 310 for a patient with hydrocephalus, the physician may use pre-programmed default values, or may select values ​​based on the patient's prior history based on previously measured pressure data and associated trends.

[0156] In some embodiments, the method of obtaining a measurement of intraparenchymal venous pressure (Pp) assumes that the intraparenchymal pressure (Pp) sensor 320 measures the higher of the intraparenchymal venous pressure (Pp) and the intraventricular CSF pressure (Pcsf). As the pressure setting of the adjustable valve 310 is reduced, Pp can track Pcsf until Pcsf drops below the Pp measurement. The Pp measurement can lead to treatment of hydrocephalus by reducing Pcsf.

[0157] exist Figure 7An example of a control process is shown in . The control process may exist as firmware in the implantable valve controller 360. The process may include measuring two pressures that may be used to determine the pressure differential between the two compartments and, therefore, the potential presence of a hydrocephalus condition. Measurements from the CSF pressure (Pcsf) sensor 330 and the intraparenchymal pressure (Pp) sensor 320 may provide an indirect measurement of the intraparenchymal venous pressure (Pp) when determining high pressure hydrocephalus (HPH).

[0158] As discussed above, pressure measurements may be obtained using electronic pressure sensors that may be mounted on the ventricular catheter 340 connected to the adjustable valve 310. Beginning with step 700, Pcsf may be measured, and then Pp may be measured as a baseline value in step 705. In step 710, an algorithm present in the valve controller 360 may reduce the valve pressure setting by a predetermined pressure (e.g., 10 mmH2O). The adjusted valve pressure setting may be set by a physician, or may be a preprogrammed default value. The valve controller 360 may then wait for a specified time interval (e.g., 1 hour) in step 715 for the pressure to stabilize, and may then repeat the measurement of Pcsf and Pp twice. The two pressure measurements may be compared in step 720, and if Pcsf is equal to Pp, the valve controller 360 may reduce the pressure setting of the adjustable valve 310 by a predetermined set pressure (e.g., 10 mmH2O), and may then wait for another specified time interval (e.g., 1 hour) to measure and evaluate the two pressures again. If the two pressures are not equal such that Pcsf is lower than Pp, the process may include identifying in step 730 that the measured Pp value may be the true intraparenchymal venous pressure Pp. In steps 735 and 740, the process may include continuing to obtain Pcsf and Pp measurements by decreasing the valve pressure setting of the adjustable valve 310 until the difference between Pcsf and Pp is greater than a second predetermined amount (e.g., 20 mmH2O) in step 740. Then, in step 745, the valve controller 360 may record the Pp value. The process may include proceeding to increase the pressure setting of the adjustable valve 310 so that in step 750, Pcsf and Pp may again be within a specified equivalence range to indicate a return to a normal state, and the valve pressure setting may be maintained in step 760.

[0159] Figure 8 An electronic block diagram of an example of a self-regulating valve system 800 is provided, which includes an implantable valve controller 805, and external instrumentation including a programmer 845 and an external wireless communication 855 module, the programmer can provide a user interface. Figure 8In the example shown in FIG. 1 , it is assumed that the implantable valve controller 805 may be expected to be small in size, so the implantable power source may also be identified as a rechargeable battery 835, as also shown in FIG. Figure 5 . The implantable rechargeable battery 835 can be charged by an external power source-charger 840 according to transcutaneous wireless power transfer methods known in the art. Wireless communication (855 and 830) between the external programmer 845 instrument and the implantable valve controller 805 can allow the physician to view recorded pressure data and view the programmed settings for the implantable valve controller 805, and can provide the physician with the ability to adjust the operating settings of the implantable valve controller 805. The wireless communication (855 and 830) can take the form of near-field electromagnetic, or use far-field RF telemetry such as the MICS (Medical Implant Communication Service) method, both of which are known in the art.

[0160] The implantable valve controller 805 may include a data acquisition module 825 for recording pressures such as Pcsf and Pp pressures 860. The data acquisition module 825 may include circuits such as amplifiers 826, filters, and (multiple) analog-to-digital (A / D) converters 828. Signals from the data acquisition module 825 may be interpreted by a microcontroller 810, which may execute firmware algorithms to implement, for example, Figure 6 and Figure 7 The implantable valve controller 805 may further include a data storage device 820, such as a flash memory, which may contain operating firmware (e.g., algorithms) and may also store measured data and / or recorded physiological data. The microcontroller 810 may also interface with a valve control circuit 815, which may be configured to control the valve control circuit according to the embodiment of the present invention. Figure 5 A signal may be sent to the hydrocephalus valve within the implantable self-regulating valve / controller 560 device to change the pressure setting of the self-regulating valve / controller 560 device. In addition, the programmer 845 may be used to retrieve data from the implantable valve controller 805 prior to intentionally exposing the valve to a strong magnetic field, such as imaging a patient using magnetic resonance imaging (MRI), to allow a physician to view the programmed operating pressure of the self-regulating valve / controller 560 device. After imaging using MRI, the programmer 845 may be used again to retrieve data from the implantable valve controller 805, and the implantable valve controller 805 may be automatically reprogrammed to the pre-MRI operating pressure setting. In addition, the programmer 845 may also store the most recently programmed settings of the implantable valve controller 805, which may be used to restore the operating pressure of the implantable valve controller 805 to the programmed settings in the event of an unexpected adjustment that may be suspected when exposed to a strong magnetic field.

[0161] As discussed above, although some examples can use implantable self-regulating valves and optionally use implantable valve controllers, in other examples, self-regulating valves and valve controllers can be kept outside the patient's body. For example, as discussed above, self-regulating valves can be connected to implanted ventricles or lumbar catheters, which can be a part of external ventricular drainage systems. Therefore, self-regulating valves can be configured to drain CSF to a position in the patient's body or to an external device (e.g., a bag or other liquid container connected to a ventricular drainage catheter). The output of the sensor (Pcsf and / or intraparenchymal pressure (Pp) sensor) can be directly output to a display screen, or an algorithm is used to process to display physiological parameters, to facilitate the clinical assessment of the patient.

[0162] Fig.9A A suitable set of pressure readings from a hydrocephalus patient treated with a self-regulating valve is shown. Figure 7 . A time-based graphical representation of an example of the process shown in . In the first stage 900, the Pp measured value can track the Pcsf measured value so that Pcsf can be greater than or equal to Pp. In the second stage 905, the Pp measured value can continue to track the Pcsf measured value when the pressure setting of the valve is reduced. Once the Pcsf measured value drops below the measured value of Pp in step 910, it can be assumed that the measured value of Pp can indicate the true intraparenchymal venous pressure (Pp). In the third stage 915, the valve pressure setting can continue to decrease until Pcsf represents the pressure required to reduce the hydrocephalus condition. In step 920, the pressure setting of the adjustable valve 310 can then be increased until Pcsf and Pp are equal again, returning to a steady state and achieving equilibrium of intracranial pressure while maintaining normal ventricular volume.

[0163] Fig. 9B and Fig. 9C The steps that can be followed in the treatment of HPH and NPH are shown respectively. As discussed above, the operating principle behind the self-regulating valve is that the gradient between Pcsf and Pp is the factor that controls the volume of the ventricles. By measuring these two parameters and adjusting Pcsf up or down relative to Pp, the adjustable valve 310 can control the volume of the ventricles by controlling the gradient between these two pressures.

[0164] In such Fig. 9BIn the first example shown in , Pcsf can initially be measured at 220 mm H2O, and the measured Pp tracks at the same value because both sensors track at the highest measured pressure value 930 in step 1. Although Pcsf may be greater than Pp, the two sensors can measure the higher of the two actual pressures. The required normal Pcsf can be equal to Pp. By slowly reducing the pressure setting of the adjustable valve 310 in step 2, this can reduce the Pcsf value, and the Pp measurement can continue to track Pcsf. Once both Pcsf and Pp reach the true Pv (representing the pressure of the superior sagittal sinus (SSS)) of 80 mm H2O at step 3, the measured value of Pp may not decrease further, but the additional reduction of Pcsf can allow the ventricular drainage of CSF 935, and a reduction in ventricular volume can occur in step 4a. After a specified interval (e.g., 1 hour), which can allow the ventricles to reach normal volume, the valve pressure setting can then be increased until Pcsf and Pp are equal again, with Pcsf slightly above the target Pp (step 4b). By achieving equalization of intracranial pressure and maintaining normal ventricular volume, a steady-state condition can then be maintained 940 with Pcsf equal to Pp and Pv (step 4c).

[0165] In such Fig. 9C In the second example shown in , Pcsf can initially be measured at a normal value of 150 mm H2O, with Pp tracking the Pcsf value. The actual Pp value may be lower at 80 mmH2O, resulting in NPH. As with HPH, in step 1, since both sensors track at the highest measured pressure value 945, the measured Pp can track Pcsf at the same value. By slowly reducing the valve pressure setting in step 2 (possibly reducing Pcsf), the Pp measurement can also continue to track Pcsf. Once the Pcsf and Pp pressures reach the true Pv of 80 mm H2O at step 3, it may not be possible to reduce Pp further, but Pcsf is additionally reduced, which can allow ventricular drainage of CSF 950 and can reduce ventricular volume, as shown in step 4a. After a specified interval (e.g., 1 hour), the valve pressure setting can then be increased until Pcsf and Pp are equal again and Pcsf is slightly above the target Pp (step 4b). By achieving equalization of intracranial pressure and maintaining normal ventricular volume, a steady-state condition can then be maintained 955 with Pcsf equal to Pp and Pv (step 4c).

[0166] for Fig. 9B and Fig. 9C Two examples, the pressure difference between Pcsf and Pp is the main factor reducing the ventricular volume conditions associated with hydrocephalus.

[0167] Several aspects of at least one embodiment have been described above, and it should be understood that those skilled in the art will readily conceive of various changes, modifications and improvements. Such changes, modifications and improvements are intended to be part of this disclosure and are intended to fall within the scope of the present invention. It should be understood that the embodiments of the methods and devices discussed herein are not limited to the details of the construction and arrangement of the components set forth in the above description or shown in the accompanying drawings in the application. These methods and devices can be implemented in other embodiments and can be practiced or executed in different ways. The examples of specific embodiments provided herein are for illustrative purposes only and are not intended to be limiting. Similarly, the words and terms used herein are for descriptive purposes and should not be considered as limiting. The use of "including", "comprising", "having", "containing", "involving" and their variations herein is intended to cover the items listed thereafter and their equivalents and other items. References to "or" can be interpreted as inclusive, so that any term described using "or" can indicate any of a single term, multiple terms, and all terms in the described terms. Accordingly, the foregoing description and drawings are by way of example only, and the scope of the present invention should be determined by proper construction of the appended claims and their equivalents.

Claims

1. A diverter valve system, comprising: an inflow catheter implanted in a ventricle of the brain or in a CSF space in the spine connected to the inlet port; a diverter valve assembly configured such that when a pressure of liquid in the inlet port exceeds a selected pressure setting of the diverter valve assembly, a valve orifice of the diverter valve assembly opens to allow liquid to be discharged through the valve orifice into the outlet port; an outflow conduit providing drainage of fluid from the outlet port to a location; The first pressure sensor is used to measure the cerebrospinal fluid pressure; A second pressure sensor, used for measuring secondary pressure; as well as an adjustable valve controller configured to change a valve pressure setting based on measurements from the pressure sensors, wherein the second pressure sensor for measuring the pressure within the substance (Pp) provides a signal representative of the measured pressure to the valve controller, Among them, the valve controller calculates the pressure difference between the measured Pcsf and Pp pressures, wherein the valve controller determines whether the pressure difference between the Pcsf and the Pp is equal to or within a specified pressure difference threshold, and Wherein, if the valve controller determines that the pressure difference between the Pcsf and the Pp is equal to or within a specified pressure difference threshold, the valve controller reduces the pressure setting of the diverter valve assembly by a predetermined value.

2. The diverter valve system of claim 1, further comprising: An external screen display that displays directly measured CSF and secondary pressure measurements in clinically useful values ​​in mmH20, mmHg as instantaneous values ​​and trend values, and displays other secondary measurements that provide information useful to the clinician.

3. The diverter valve system of claim 1, wherein: The first pressure sensor is a transducer for said measurement of cerebrospinal fluid pressure (Pcsf) and for providing a first electrical signal representative of the measured pressure to the valve controller.

4. The diverter valve system according to any one of claims 1 to 3, wherein: The second pressure sensor is a transducer for said measurement of the intraparenchymal pressure (Pp) and for providing a second electrical signal representative of the measured pressure to the valve controller.

5. The diverter valve system of claim 1, wherein: The first pressure sensor is configured to measure cerebrospinal fluid pressure (Pcsf) within a ventricle of the brain; The second pressure sensor is configured to indirectly measure a second pressure (Pp) within the space of the brain.

6. The diverter valve system of claim 5, wherein: If the measured cerebrospinal fluid pressure of the ventricle (Pcsf) relative to the secondary pressure of the space of the brain (Pp) is equal to or within a specified pressure differential threshold, the valve controller reduces the pressure of the ventricle of the brain by a predetermined pressure value.

7. The diverter valve system of claim 6, wherein: Indirectly measuring the second pressure (Pp) includes the second pressure sensor indirectly measuring the intraparenchymal pressure within the parenchymal space of the brain, wherein the valve controller is configured to continue to reduce the pressure within the ventricle of the brain until the Pcsf pressure measurement is lower than the Pp pressure measurement by the specified pressure differential threshold.

8. The diverter valve system of claim 7, wherein: The Pp measurement represents the true intraparenchymal venous pressure.

9. The diverter valve system according to any one of claims 5 to 8, wherein: The reduction in cerebrospinal fluid pressure is used to treat at least one of high-pressure hydrocephalus, normal-pressure hydrocephalus, or other types of dementia.

10. The diverter valve system according to any one of claims 5 to 8, wherein: This reduction in cerebrospinal fluid pressure treats the condition pseudotumor cerebri (idiopathic intracranial hypertension).

11. The diverter valve system according to any one of claims 5 to 8, wherein: The shunt valve system is configured to continuously measure Pcsf and Pp to provide a steady-state balance of ventricular volume and intraparenchymal venous pressure.

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