Programmable CSF metering shunt
An implantable body fluid drainage system includes a metering shunt having a housing with an internal chamber. A movable barrier divides the chamber into a first section and a second section, and the barrier can be displaced by a differential pressure. A first powered inlet valve providing a fill path to the first section of the chamber, and a first powered drain valve providing a drain path from the first section of the chamber. A CSF inlet conduit connects a CSF space to the first powered inlet valve. A CSF outlet conduit connects the first powered outlet valve to a discharge location. A controller opens the first powered inlet valve and close the first powered drain valve to fill the first section to a volume defined by the barrier and chamber geometry and closes the first powered inlet valve and opens the first powered drain valve to discharge the filled volume from the first section through the outlet conduit.
1 . A method for controlling cerebrospinal fluid (CSF) drainage in a patient having a CSF metering shunt implanted to drain CSF from the patient's central nervous system (CNS), the method comprising:
measuring one or more intracranial parameters of the patient with an implanted CSF metering shunt;
measuring a position of the patient;
removing a known volume of CSF from the patient's CSF space using the CSF metering shunt;
calculating a control parameter with the measured one or more intracranial parameters and the measured position; and
using the control parameter to adjust a performance of the implanted CSF metering shunt, wherein adjusting the performance of the implanted CSF metering shunt comprises collecting and transmitting CSF production rate diagnostic data.
2 . The method of claim 1 , wherein the one or more measured intracranial parameters are pressure measurements.
3 . The method of claim 2 , wherein the pressure measurements include one or more of an intracranial pressure, a hydrostatic head pressure, or a valve outflow pressure.
4 . The method of claim 1 , wherein the control parameter is calculated by the CSF metering shunt.
5 . The method of claim 3 , further comprising measuring a CSF production rate.
6 . The method of claim 5 , wherein the CSF production rate is calculated by a change in intracranial pressure over time.
7 . The method of claim 5 , wherein measuring the CSF production rate comprises:
monitoring an initial intracranial pressure;
draining a predetermined volume of CSF;
measuring a reduced intracranial pressure;
recording, as a function of time, an increase in intracranial pressure until it returns to the initial intracranial pressure; and
calculating the CSF production rate by dividing the volume of CSF drained by time to return to the initial inter-cranial pressure.
8 . The method of claim 3 , further comprising determining the position of the patient via the hydrostatic head pressure, wherein the hydrostatic head pressure is associated with an outflow of the implanted CSF metering shunt.
9 . The method of claim 1 , wherein measuring the one or more intracranial parameters comprises measuring the one or more intracranial parameters via one or more chambers, diaphragms, valves, or any combination thereof.
10 . The method of claim 9 , wherein measuring the one or more intracranial parameters comprises displacing an elastic material comprising the one or more chambers based on changes in fluid pressure.
11 . The method of claim 10 , wherein displacing the elastic material comprises sealing an orifice, displacing a fluid, or both based on a pressure differential across the elastic material of the one or more chambers.
12 . The method of claim 11 , wherein the one or more chambers comprises two or more chambers, wherein measuring the one or more intracranial parameters comprises creating a piston via connecting the two or more chambers.
13 . The method of claim 12 , further comprising measuring, via the piston, an associated pressure attenuation based on the pressure differential across the elastic material of the two or more chambers.
14 . The method of claim 1 , wherein adjusting the performance of the implanted CSF metering shunt is configured to provide consistent CSF flow and turnover rate.
15 . The method of claim 14 , wherein providing consistent CSF flow and turnover rate improves metabolite clearance, minimizes over-shunting, and treats dementia, gait, and urinary disorders associated with NPH and AD.
16 . The method of claim 2 , wherein the one or more measured intracranial parameters comprises a time input corresponding to the pressure measurements.
17 . The method of claim 16 , wherein the time input comprises a time of day, duration of operation, or duration of inoperation.
18 . The method of claim 1 , further comprising:
measuring an initial intracranial pressure;
transferring a known volume of CSF from an input to an output of the implanted CSF metering shunt in a minimum amount of time, wherein the known volume comprises one or more metering cycles;
remeasuring intracranial pressure;
removing the known volume of CSF; and
estimating a CSF production by dividing the known transferred CSF volume by the time it takes for the intracranial pressure to return to the initial intracranial pressure.
19 . The method of claim 1 , wherein adjusting the performance of the implanted CSF metering shunt comprises adjusting a schedule of the performance of the implanted CSF metering shunt based on the diagnostic data.
20 . The method of claim 1 , wherein adjusting the performance of the implanted CSF metering shunt comprises one or more of maintaining a flow set point, maintaining a pressure set point, or controlling perfusion.
21 . A method for controlling cerebrospinal fluid (CSF) drainage in a patient having a CSF metering shunt implanted to drain CSF from the patient's central nervous system (CNS), the method comprising:
measuring one or more pressure measurements that include one or more of an intracranial pressure, a hydrostatic head pressure, or a valve outflow pressure of the patient with an implanted CSF metering shunt;
measuring a position of the patient;
measuring a CSF production rate by;
monitoring an initial intracranial pressure;
draining a predetermined volume of CSF with the implanted CSF metering shunt;
measuring a reduced intracranial pressure;
recording, as a function of time, an increase in intracranial pressure until it returns to the initial intracranial pressure; and
calculating the CSF production rate by dividing the volume of CSF drained by time to return to the initial intracranial pressure;
calculating a control parameter with the measured intracranial pressures, the measured position, and the measured CSF production rate; and
using the control parameter to adjust a performance of the implanted CSF metering shunt.
22 . A method for controlling cerebrospinal fluid (CSF) drainage in a patient having a CSF metering shunt implanted to drain CSF from the patient's central nervous system (CNS), the method comprising:
measuring an initial intracranial pressure of the patient with an implanted CSF metering shunt;
measuring a position of the patient;
moving a known volume of CSF from an input to an output of the implanted CSF metering shunt in a minimum amount of time, wherein the known volume comprises one or more metering cycles;
remeasuring the intracranial pressure;
estimating a CSF production rate by dividing the known volume of CSF by the time it takes for the intracranial pressure to return to the initial intracranial pressure;
calculating a control parameter with the measured intracranial pressures, the measured position, and the measured CSF production rate; and
using the control parameter to adjust a performance of the implanted CSF metering shunt.