Noninvasive thermal evaluation for shunt failure in the emergency room

Abstract

Background:Ventriculoperitoneal shunts (VPSs) have been the mainstay of treating hydrocephalus since the 1950s. However, shunts have a reported complication rate reaching nearly 50%. Devices have been developed that utilize noninvasive thermal transcutaneous diffusion technology. These shunt evaluation devices measure temperature gradients to detect shunt cerebrospinal fluid flow. We assessed the utility using a thermal diffusion technique to work up shunt failure in the emergency room (ER).Methods:This was a retrospective case series at a single medical center ER. We included consecutive patients with possible VPS malfunction who were evaluated with a thermal sensor. The time period of data collection included September 2015–April 2018.Results:Eight patients were reviewed, including four males and four females. The average age of reviewed patients was 35.1 (+/− ; 16.5). In our case series, three patients had adequate shunt flow as assessed by the shunt evaluation device, and the decision was made to discharge the patient and follow-up in clinic. In two patients, the flow was diminished, but due to other reassuring signs, the patients were still discharged with follow-up. Two patients were noted to have poor flow and were admitted for shunt revision.Conclusion:It is important to determine whether a malfunction is present and whether an intervention is necessary for patients who present to the emergency department with possible symptoms of shunt failure. A thermal sensor is a fast and noninvasive tool in the evaluation of shunt flow and helps determine whether it is safe to send a patient home or intervene appropriately.

Volumetric effect of shunt adjustments in normal pressure hydrocephalus: a randomized, double-blind trial

“…Phase-contrast MRI on the flow in the catheter has been considered for noninvasive shunt function testing, although this method seemed less sensitive in iNPH than in obstructive hydrocephalus. 35,36 Ultrasound 37 and thermal sensing 38 have been presented as other possible methods of noninvasive shunt testing, but to our knowledge have not been tried in patients with iNPH, in which flow-based methods are potentially less reliable due to lower flow rates when compared with obstructive hydrocephalus. Despite the 1-month run-in period after surgery at PL 1.5, 8 participants developed subdural effusions, all of them at PL 1.0.…”

Multimodal Sensing Capabilities for the Detection of Shunt Failure

“…A recent study proposed to determine whether a shunt is malfunctioning through a non-invasive device that can estimate the catheter flow rate as a function of temperature change. The existing non-invasive approach uses localized thermal actuation, but CSF flow rate calculation is heavily dependent on variable parameters, such as skin thickness and thermal properties that vary in individuals [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. This indicates that a threshold for detection of shunt failure can vary in individuals, and that a setting for measurements of CSF flow rate must be customized to an individual.…”