Microfabricated Implantable Flowmeter for CSF Shunts Phase II

用于脑脊液分流的微型植入式流量计第二阶段

• 批准号: 8123068
• 负责人: JAMES Hunter GOLDIE
• 金额: $ 99.88万
• 依托单位: INFOSCITEX CORPORATION
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-30 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8123068
• 关键词: Achievement; Animal Model; Animal Testing; Appearance; Calibration; Cerebrospinal fluid shunts procedure; Characteristics; Child; Chronic; Clinical; Clinical Trials; Coupling; Creation of ventriculo-peritoneal shunt; Data; Deposition; Detection; Development; Devices; Early Diagnosis; Electromagnetics; Emergency Situation; Ensure; Environment; Failure; Flowmeters; Frequencies; Hydrocephalus; Implant; In Situ; Indium; Laboratories; Liquid substance; Magnetic Resonance Imaging; Maps; Measurable; Measurement; Measures; Methods; Microfabrication; Modeling; Monitor; Obstruction; Office Visits; Output; Patients; Performance; Peritoneal; Phase; Physiological; Preparation; Probability; Process; Property; Protocols documentation; Pump; Reading; Relative (related person); Reporting; Risk; Risk Management; Safety; Sensitivity and Specificity; Sheep; Shunt Device; Specific qualifier value; Sterilization; Structure; Symptoms; System; Testing; Time; Tissues; Variant; Visit; Wireless Technology; base; biomaterial compatibility; cerebrospinal fluid flow; design; electrical property; feeding; fluid flow; hazard; implantation; implanted sensor; in vitro testing; meetings; meter; mortality; operation; phantom model; prototype; research study; seal; sensor; tissue phantom

DESCRIPTION (provided by applicant): An implantable wireless flow sensor system has been under development that would enable measurement of the flow of cerebrospinal fluid (CSF) through the ventriculoperitoneal (VP) shunt, currently used to treat hydrocephalus patients. CSF flow is a key indicator of shunt function, and there is currently no way to measure it in situ, resulting in the absence of clinical methods to directly assess shunt function or to predict its failure. Using MEMS microfabrication methods, the proposed flow sensor will be manufactured at a size small enough to be integrable with implanted VP shunts. The key elements in the flow meter are capacitive structures that change properties with change in CSF flow. Electromagnetic coupling between the internal passive circuitry and an external handheld circuit allows implantation of the flow sensor without the need for implanted batteries or transcutaneous wires. The proposed Phase II project will build on the encouraging results of Phase I, which demonstrated the wireless interrogation of proof-of-concept MEMS sensors and the presence of a readily measurable relationship of flow to the resonance of the sensor. In Phase II, fully-function flow-sensing MEMS chips will be manufactured, as well as a revised handheld unit that will display and output flow, based on the known relationship between flow rate and resonance. In vitro testing will establish calibration for the sensor implants, and will demonstrate measurement accuracy over the full physiological range of CSF flow, over long periods of time, and with appropriate phantom models. In parallel, a chronic sheep hydrocephalus model will be in preparation, along with implementation of appropriate packaging, biocompatibility, and sterilizability into the sensor implant prototypes, as well as consideration of MR compatibility. Performance of an animal test protocol shall evaluate the sensor in regard to (1) sensitivity and specificity with regard to detection of flow obstruction, (2) CSF flow measurement accuracy, and (3) effect on shunt patency. PUBLIC HEALTH RELEVANCE: Every year there are approximately 23,000 shunt revisions performed in the U.S., in order to correct the relatively common failure of ventriculoperitoneal (VP) shunts used to treat hydrocephalus patients. However, children are still dying from shunt failure, and studies indicate that earlier detection would save a large fraction of these children. An implantable, wireless CSF flow meter would enable the clinician to monitor shunt function during routine office visits (rather than waiting for the re-appearance of hydrocephalus symptoms), allowing detection of impending shunt failure, avoidance of lifesaving treatment on an emergency basis, and reduction of mortality associated with VP shunt failure.

描述（由申请人提供）： 一种植入式无线流量传感器系统正在开发中，该系统可以测量通过脑室腹膜（VP）分流器的脑脊液（CSF）流量，目前用于治疗脑积水患者。脑脊液流量是分流功能的关键指标，目前尚无方法对其进行原位测量，导致临床上缺乏直接评估分流功能或预测其失败的方法。使用 MEMS 微加工方法，所提出的流量传感器的尺寸将足够小，以便与植入的 VP 分流器集成。流量计的关键元件是电容结构，其特性会随着 CSF 流量的变化而改变。内部无源电路和外部手持式电路之间的电磁耦合允许植入流量传感器，而无需植入电池或经皮电线。拟议的第二阶段项目将建立在第一阶段令人鼓舞的成果的基础上，该项目展示了概念验证 MEMS 传感器的无线询问以及流量与传感器谐振之间存在易于测量的关系。在第二阶段，将制造全功能的流量传感 MEMS 芯片，以及改进的手持单元，该单元将根据流量和共振之间的已知关系来显示和输出流量。体外测试将为传感器植入物建立校准，并将在长时间内并使用适当的体模模型证明脑脊液流量的整个生理范围内的测量准确性。与此同时，还将准备慢性绵羊脑积水模型，并在传感器植入原型中实施适当的包装、生物相容性和灭菌性，并考虑 MR 兼容性。动物测试方案的性能应评估传感器的以下方面：(1) 检测血流阻塞的灵敏度和特异性，(2) 脑脊液流量测量精度，以及 (3) 对分流通畅的影响。 公共卫生相关性： 美国每年大约进行 23,000 例分流修复手术，以纠正用于治疗脑积水患者的脑室腹膜 (VP) 分流术相对常见的失败。然而，仍有儿童因分流失败而死亡，研究表明，及早发现可以挽救大部分儿童的生命。植入式无线脑脊液流量计将使临床医生能够在例行就诊期间监测分流功能（而不是等待脑积水症状再次出现），从而检测即将发生的分流失败，避免紧急情况下的救生治疗，以及降低与 VP 分流失败相关的死亡率。