Method of regulating CSF drainage
Inventors
Negre, Philippe • Moureaux, Christophe • Boyer, Christophe • Bonnal, Olivier
Assignees
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Publication Number
US-9072865-B2
Publication Date
2015-07-07
Expiration Date
Abstract
An implantable drainage device for draining the cerebro-spinal fluid of a patient, the device including: a drainage valve including a valve member and a valve seat;a control unit suitable for modifying an operating parameter of said valve, at least as a function of a measurement (D) of the fluid flow rate through said valve;an actuator controlled by the control unit, suitable for modifying the operation of said valve as a function of said operating parameter as modified by the control unit; anda mass flowmeter suitable for evaluating said flow rate of fluid through said valve.
Core Innovation
The invention relates to an implantable drainage device for draining a patient's cerebro-spinal fluid, the device including a drainage valve comprising a valve member and a valve seat. A control unit modifies an operating parameter of the valve at least as a function of a measurement (D) of the fluid flow rate through the valve, and an actuator is controlled so as to modify the operation of the valve as a function of the operating parameter as modified by the control unit.
The device includes a mass flowmeter suitable for taking the measurement (D) of the flow rate through the valve. The control strategy servo-controls the measured flow rate toward the setpoint flow rate (D*), using valve operating parameters associated with passive opening pressure (P0), progressive opening degree (Δθ0 and/or duration), or on/off opening frequency (F0) and bolus duration tb.
The control unit re-evaluates a setpoint flow rate (D*) at regular intervals and/or following a particular event, including calibration of the mass flowmeter measurement of D. The device supports intermittent drainage mode and permanent drainage mode, with intermittent power use to reduce energy, and includes cleaning stage behavior in which the control unit mechanically separates the valve member from the valve seat to clear obstructions.
Safety controls include limiting a flow accuracy range and a safe range of flow, limiting flow rate (DL), and providing a safety opening triggered when a pressure difference exceeds a safe pressure (Ps). External radio-frequency communication enables external programming and data/power transfer.
Claims Coverage
The document contains one independent claim directed to the implantable CSF drainage device with a mass flowmeter-controlled valve using periodic/event-driven setpoint re-evaluation. The dependent claims refine the timing/triggering of setpoint re-evaluation, the measurement timing during drainage stages, cleaning-stage valve-member/seat separation, safety opening based on pressure-difference thresholds, and communication via a radio-frequency link.
Mass flowmeter-controlled implantable CSF drainage valve
An implantable drainage device for draining a patient's cerebro-spinal fluid including a drainage valve having a valve member and a valve seat, the device including a mass flowmeter suitable for taking a measurement (D) of a flow rate of fluid through the valve, and a control unit suitable for modifying an operating parameter of the valve at least as a function of the measurement (D) of the fluid flow rate through the valve.
Periodic and event-driven re-evaluation of flow setpoint
The control unit is also suitable for re-evaluating a setpoint flow rate (D*) at regular intervals and/or following a particular event.
Actuator-based valve operation as a function of modified operating parameter
An actuator controlled by the control unit, suitable for modifying the operation of the valve as a function of the operating parameter as modified by the control unit.
Setpoint re-evaluation timing and event triggers
The device re-evaluates a setpoint flow rate (D*) every hour and/or immediately after implantation and/or upon detection of an abnormal flow rate.
Flow measurement during drainage stages
A mass flowmeter measures the flow rate only during drainage stages.
Cleaning-stage valve member separation from the seat
During a cleaning stage, the control unit positions the valve member at least 0.5 mm away from the seat of the drainage valve.
Safety opening tied to upstream-to-downstream pressure difference
The device includes actuator and resilient return safety means such that a safety opening occurs when the upstream-to-downstream pressure difference across the drainage valve seat exceeds a safe pressure.
Radio-frequency communication for external control instructions
The device includes communication means using a radio frequency link to receive and/or send external control instructions to and from outside the patient's body.
Overall claim coverage centers on an implantable CSF drainage device that uses a mass flowmeter measurement (D) of flow rate through the drainage valve to modify valve operating parameters via a control unit and actuator. The control unit periodically and/or event-driven re-evaluates a setpoint flow rate (D*), and dependent claims refine measurement timing to drainage stages, cleaning-stage separation between valve member and seat, a safety opening when pressure difference exceeds a safe pressure, and radio-frequency communication for external control instructions.
Stated Advantages
The device supports intermittent power use to reduce energy.
Safety controls include limiting a flow accuracy range and a safe range of flow, limiting flow rate (DL), and providing a safety opening triggered when a pressure difference exceeds a safe pressure (Ps).
The control unit mechanically separates the valve member from the valve seat to clear obstructions.
Documented Applications
Implantable drainage of a patient's cerebro-spinal fluid.
External programming and data/power transfer via radio-frequency communication.
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