By Jacob Getzoff and Dr. Jenna Koschnitzky, HA Director of Research Programs
Recently, a group of scientists at the New Jersey Institute of Technology tested a sensor that uses microtechnology to detect developing occlusions, or blockages, within a shunt. The device may also be able to predict where the occlusion is forming and how much longer the shunt can function before the occlusion completely stops the flow of cerebrospinal fluid (CSF).
The sensor has a small membrane that flexes when the pressure inside of the shunt tubing changes. When the membrane flexes, a change in electrical signal is produced. This change in signal can be read wirelessly using a special external device, similar to the devices used to program most shunt valves. If the pressure inside the shunt changes, this would mean that there is likely an occlusion forming.
The sensor may also be able to indicate the location of the occlusion. If the pressure inside the shunt begins to increase, this would suggest that there is an occlusion on the distal end of the shunt, near the peritoneum (abdominal cavity). This is because the CSF would be unable to flow past the occlusion and out of the tubing. If the blockage were on the proximal end of the shunt, near the ventricles, less CSF would flow through the shunt, and the sensor would show a decrease in pressure.
In some cases, changes in pressure due to occlusions occur gradually. The researchers simulated this by pinching the shunt tubing tighter and tighter at a constant rate. While slowly pinching the tubing, they measured the incoming signals from the sensor and found that mathematical models could describe the changes in signal. If there is an occlusion forming, these models can be used to predict how much longer the shunt will function until it is completely occluded. For example, if a doctor noticed that the signal from the sensor has decreased since a patient’s last visit, they could make a rough estimate of when the sensor will indicate total blockage.
If this technology is successful, the sensor could be extremely helpful to doctors. The readings from the sensor could provide doctors with more information to rely on when making a diagnosis of shunt occlusion. Additionally, the ability to predict when shunt revisions may be necessary would give doctors more time to schedule a shunt revision before any changes in intracranial pressure could cause damage to brain tissue.
While this device is not yet ready for human trials, the technology is a great example of the progress being made towards a safer shunt. The research team conducting this study included David J. Apigo, Philip L. Bartholomew, Thomas Russell, Alokik Kanwal, Reginald C. Farrow, and Gordon A. Thomas. The full article can be found here.