This study evaluates the performance of a non-invasive thermal measurement device for assessing CSF shunt flow. Patients with an existing implanted shunt and symptoms of shunt malfunction will be evaluated with the study device.

Patients with an existing implanted ventriculoperitoneal (VP) shunt and who are experiencing shunt malfunction symptoms will be recruited by the clinical investigators at each investigational site in accordance with the inclusion and exclusion criteria. Assessment of shunt flow will be performed non-invasively with the study device; physician and clinical staff will be blinded to the device result. Standard-of-care assessment of shunt function will be performed and surgical intervention will occur based on the judgement of the treating neurosurgeon without the use of study device data. This trial will evaluate the ability of the study device to identify shunt malfunctions.

Inclusion criteria

1. Existing ventriculoperitoneal CSF shunt on which the patient is dependent
2. At least one symptom of shunt malfunction as determined by the investigator, such as but not limited to seizure, fever, headache, vision problems, dizziness, disorientation, confusion, vomiting, lethargy, irritability, difficulty waking or staying awake, swelling along shunt tract, enlargement of head, loss of balance, gait disturbance, and loss of sensory or motor function
3. Suspicion of shunt obstruction warrants the performance of a test for this condition in the investigator's judgement
4. Region of intact skin overlying an unambiguously identifiable chronically indwelling ventricular shunt which crosses the clavicle and is appropriate in size for application of the study device
5. Available for follow-up for up to seven days
6. Signed informed consent by patient or a parent, legal guardian, health care agent, or surrogate decision maker (according to local statutes, and collectively referred to as "surrogates" in this protocol)
7. Verbal assent by minors four years of age and older who are able to understand the study and communicate their decision

Exclusion criteria

1. Presence of multiple shunts, or presence of more than one distal shunt catheter (regardless of function) crossing the clavicle ipsilateral to the shunt with suspected obstruction
2. Use of the study device would interfere with standard patient care, or emergency surgery that cannot be delayed
3. Presence of an interfering open wound or edema over any portion of the shunt
4. Patient-reported history of adverse skin reactions to adhesives
5. Investigator judges that the subject is likely to be lost to follow-up due to unavailability or clinical outcome being unobtainable
6. Participation in the study will interfere with, or be detrimental to, administration of optimal health-care to the subject
7. Prior enrollment in this study (multiple main study enrollments of the same patient are disallowed)
8. Participation in any other investigational procedural, pharmaceutical, and/or device study that may influence the collection of valid data under this study

hydrocephalus patients with an existing ventriculoperitoneal shunt and shunt malfunction symptoms

The total number of baseline participants (N=139) includes all subjects in which a device measurement was attempted (132 subjects with complete measurements and 7 subjects with incomplete measurements)

20 minutes

Patients were evaluated for adverse events during the use of the study device and for a period of 20 minutes thereafter. The total at risk count (N=139) includes all subjects in which a device measurement was attempted (132 subjects with complete measurements and 7 subjects with incomplete measurements)