ShuntCheck

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ShuntCheck
SCIII 4 PlaceTS and SCIII 12 PlaceIce.jpg
ShuntCheck Sensor & Ice Placement
UsesDetects flow in the cerebral shunts of hydrocephalus patients
ApproachNon-invasive

ShuntCheck is a non-invasive diagnostic medical device which detects flow in the cerebral shunts of hydrocephalus patients. Neurosurgeons can use ShuntCheck flow results along with other diagnostic tests to assess shunt function and malfunction. [1]

Contents

Hydrocephalus is a condition in which cerebrospinal fluid (CSF) accumulates in the brain, potentially leading to brain damage and death. It is corrected by a shunt which drains excess CSF from the brain to the abdomen. Shunts fail, typically by obstruction – a life-threatening medical condition requiring the surgical replacement of the shunt. The symptoms of shunt failure are non-specific – headache, nausea, lethargy – so diagnostic tests must be conducted to rule in or rule out surgery. Current methods of diagnosing shunt malfunction, including CT Scan, MRI, radionuclide studies and shunt tap, have limitations and risks. These limitations and risks led to the development of ShuntCheck. [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [ excessive citations ]

ShuntCheck uses thermal dilution [14] [15] to detect flow. The ShuntCheck sensor, a high-tech skin thermometer, is placed over the shunt where it crosses the clavicle. The shunt, which lies just below the skin, is cooled with an ice pack placed “upstream” of the sensor. If CSF is flowing through the shunt, the cooled fluid will move “downstream” and the ShuntCheck sensor will detect a drop in temperature. Faster shunt flow results in greater temperature decreases. If the shunt is not flowing, the cooled fluid remains upstream and no temperature drop is recorded. [2]

The sensor is connected to a laptop or tablet computer running ShuntCheck software. The sensor is connected to a laptop or tablet computer running ShuntCheck software. The computer analyzes the thermal data, determines “Flow Confirmed” or “Flow NOT Confirmed” and presents a time-temperature graph.

ShuntCheck Results Screen Wiki graph.jpg
ShuntCheck Results Screen

Early clinical testing of ShuntCheck found that functioning shunts flow intermittently, which meant that a ShuntCheck reading of “Flow NOT Confirmed” did not necessarily indicate a shunt problem. [2] [16] This discovery led to the development of the ShuntCheck Micro-Pumper, a handheld device which vibrates the shunt valve, generating a temporary increase in flow through patent, but not through obstructed, shunts. Micro-Pumper allows ShuntCheck to differentiate between temporarily non-flowing patent shunts and obstructed shunts. [1]

Micro-Pumper SCIII Micro-Pumper & SCIII 14 MP.jpg
Micro-Pumper

ShuntCheck III

The current version of ShuntCheck was developed in 2011-2012 funded by grants from the National Institute of Health [17] [18] [19] and was cleared by the US FDA in 2013. [1] The ShuntCheck system includes the ShuntCheck Sensor, a skin marker, an Instant Cold Pack, a Data Acquisition Unit (an analog-to-digital converter called the “DAQ”), a Windows 7 or Windows 8 laptop or tablet computer running ShuntCheck software and the Micro-Pumper. [1]

ShuntCheck System SCIII System.JPG
ShuntCheck System

ShuntCheck clinical studies

Boston Children's Hospital 2008-2009 Joseph R. Madsen MD tested 100 symptomatic and asymptomatic pediatric hydrocephalus patients using an earlier version of ShuntCheck during 2008–2009. His key findings, reported in Neurosurgery [2] were

University of South Florida 2008 Arthur E. Marlin MD and Sarah J Gaskill MD conducted ShuntCheck testing on 35 asymptomatic pediatric patients with similar results. [16]

These findings led to the development of the Micro-Pumper.

Boston Children's Hospital 2010-2013 Dr. Madsen is testing 130 symptomatic and asymptomatic pediatric hydrocephalus patients to assess the diagnostic accuracy and clinical utility of the newer version of ShuntCheck including Micro-Pumper. This study was funded by the NIH. [18] [19]

Multi-Center Pediatric Outcomes Study 2013-2014 Boston Children's Hospital, Children's Hospital of Philadelphia, Johns Hopkins Hospital, Cleveland Clinic, University of Chicago Comer Children's Hospital, LeBonheur Children's Hospital and University of Texas Houston Children's Memorial Hermann Hospital will conduct an outcomes study of 400 symptomatic pediatric hydrocephalus patients during 2013–2014. In this NIH funded study, [19] ShuntCheck results and the results of standard of care diagnostic tests will be compared to clinical outcome (shunt obstruction confirmed by surgery vs no-obstruction). This study [20] seeks to demonstrate that

Sinai Baltimore NPH Study 2012-2014 Michael A. Williams MD is conducting ShuntCheck testing on adult hydrocephalus patients undergoing radionuclide shunt patency testing. This study, funded by the NIH, [21] [22] seeks to demonstrate that ShuntCheck results match radionuclide results.

Potential clinical uses of ShuntCheck

  1. A test for assessing shunt function in symptomatic hydrocephalus patients. ShuntCheck flow data, used in conjunction with other diagnostic test results and with physician judgment, can aid in ruling in or ruling out shunt obstruction. [1]
  2. A tool for establishing “normal” CSF flow patterns in asymptomatic patients. Establishing baseline flow may increase the value of flow information in symptomatic patients. [1]
  3. A tool to streamline the process of adjusting shunt valve settings to accommodate individual needs for CSF drainage. While the settings for these valves in each patient must currently be determined empirically over a number of weeks, Shuntcheck will be helpful in measuring changes in CSF flow due to changes in the valve setting. [23]
  4. A tool for assessing suspected over-drainage. CSF flow data will allow neurosurgeons to identify periods and causes of high CSF flow when assessing suspected CSF over drainage. This data can also be used to evaluate flow and siphon control devices to determine if they are meeting the patient's needs.
  5. A post operative test to confirm shunt function. Hospitals in sparsely populated areas often conduct post-surgical CT scans to confirm shunt function before releasing patients for the long drive home. CSF flow data can confirm shunt function more quickly than CT (which requires time for the ventricles to stabilize).

NeuroDx Development

NeuroDx Development [10] (NeuroDx) is an early commercial stage medical device company founded in 2008 by Fred Fritz (CEO), a serial life sciences entrepreneur, and Dr. Marek Swoboda (Chief Scientific Officer), a biosensor engineer, to address important unmet needs in the hydrocephalus market. [24] The company has developed two thermal dilution technologies for assessing shunt function in hydrocephalus patients, ShuntCheck-Micro-Pumper, an eight-minute test of CSF shunt flow, and Continuous Real Time (CRT) ShuntCheck, which uses thermal dilution to monitor changes in shunt flow over longer time periods. [25] The company's follow-on products, an implantable intracranial pressure monitoring device [26] and a non-invasive monitor of intracranial pressure, are in proof of concept development.

Related Research Articles

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<span class="mw-page-title-main">Idiopathic intracranial hypertension</span> Medical condition

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<span class="mw-page-title-main">Hydrocephalus</span> Abnormal increase in cerebrospinal fluid in the ventricles of the brain

Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary incontinence, personality changes, or mental impairment. In babies, it may be seen as a rapid increase in head size. Other symptoms may include vomiting, sleepiness, seizures, and downward pointing of the eyes.

<span class="mw-page-title-main">Chiari malformation</span> Structural defect in the cerebellum of the brain

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<span class="mw-page-title-main">Hydranencephaly</span> Medical condition

Hydranencephaly is a condition in which the brain's cerebral hemispheres are absent to a great degree and the remaining cranial cavity is filled with cerebrospinal fluid. "Cephalic" is the scientific term for "head" or "head end of body".

<span class="mw-page-title-main">Lumbar puncture</span> Procedure to collect cerebrospinal fluid

Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine. Examples of these conditions include meningitis and subarachnoid hemorrhage. It may also be used therapeutically in some conditions. Increased intracranial pressure is a contraindication, due to risk of brain matter being compressed and pushed toward the spine. Sometimes, lumbar puncture cannot be performed safely. It is regarded as a safe procedure, but post-dural-puncture headache is a common side effect if a small atraumatic needle is not used.

Normal pressure hydrocephalus (NPH), also called malresorptive hydrocephalus, is a form of communicating hydrocephalus in which excess cerebrospinal fluid (CSF) builds up in the ventricles, leading to normal or slightly elevated cerebrospinal fluid pressure. The fluid build-up causes the ventricles to enlarge and the pressure inside the head to increase, compressing surrounding brain tissue and leading to neurological complications. Although the cause of idiopathicNPH remains unclear, it has been associated with various co-morbidities including hypertension, diabetes mellitus, Alzheimer's disease, and hyperlipidemia. Causes of secondary NPH include trauma, hemorrhage, or infection. The disease presents in a classic triad of symptoms, which are memory impairment, urinary frequency, and balance problems/gait deviations. The disease was first described by Salomón Hakim and Raymond Adams in 1965.

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<span class="mw-page-title-main">Bidirectional Glenn procedure</span>

The bidirectional Glenn (BDG) shunt, or bidirectional cavopulmonary anastomosis, is a surgical technique used in pediatric cardiac surgery procedure used to temporarily improve blood oxygenation for patients with a congenital cardiac defect resulting in a single functional ventricle. Creation of a bidirectional shunt reduces the amount of blood volume that the heart needs to pump at the time of surgical repair with the Fontan procedure.

<span class="mw-page-title-main">External ventricular drain</span> Medical device

An external ventricular drain (EVD), also known as a ventriculostomy or extraventricular drain, is a device used in neurosurgery to treat hydrocephalus and relieve elevated intracranial pressure when the normal flow of cerebrospinal fluid (CSF) inside the brain is obstructed. An EVD is a flexible plastic catheter placed by a neurosurgeon or neurointensivist and managed by intensive care unit (ICU) physicians and nurses. The purpose of external ventricular drainage is to divert fluid from the ventricles of the brain and allow for monitoring of intracranial pressure. An EVD must be placed in a center with full neurosurgical capabilities, because immediate neurosurgical intervention can be needed if a complication of EVD placement, such as bleeding, is encountered.

<span class="mw-page-title-main">CSF tap test</span>

The CSF tap test, sometimes lumbar tap test or Miller Fisher Test, is a medical test that is used to decide whether shunting of cerebrospinal fluid (CSF) would be helpful in a patient with suspected normal pressure hydrocephalus (NPH). The test involves removing 30-50 ml of cerebrospinal fluid (CSF) through a lumbar puncture, after which motor and cognitive function is clinically reassessed. The name "Fisher test" is after C. Miller Fisher, a Canadian neurologist working in Boston, Massachusetts, who described the test.

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Aqueductal stenosis is a narrowing of the aqueduct of Sylvius which blocks the flow of cerebrospinal fluid (CSF) in the ventricular system. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus.

Cerebrospinal fluid (CSF) flow MRI is used to assess pulsatile CSF flow both qualitatively and quantitatively. Time-resolved 2D phase-contrast MRI with velocity encoding is the most common method for CSF analysis. CSF Fluid Flow MRI detects back and forth flow of Cerebrospinal fluid that corresponds to vascular pulsations from mostly the cardiac cycle of the choroid plexus. Bulk transport of CSF, characterized by CSF circulation through the Central Nervous System, is not used because it is too slow to assess clinically. CSF would have to pass through the brain's lymphatic system and be absorbed by arachnoid granulations.

References

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