Fiber-Optic Intracranial Pressure Monitoring System Using Wi-Fi—An In Vivo Study

Neurosurgery 92:647–656, 2023

Continuous invasive monitoring of intracranial pressure (ICP) is essential in neurocritical care for surveillance and management of raised ICP. Fluid-based systems and strain gauge microsensors remain the current standard. In the past few decades, several studies with wireless monitoring were developed aiming to reduce invasiveness and complications.

OBJECTIVE: To describe a novel Wi-Fi fiber-optic device for continuous ICP monitoring using smartphone in a swine model.

METHODS: Two ICP sensors (wireless prototype and wire-based reference) were implanted in the cerebral parenchyma of a swine model for a total of 120 minutes of continuous monitoring. Every 5 minutes, jugular veins compression was performed to evaluate ICP changes. The experimentation was divided in 3 phases for comparison and analysis.

RESULTS: Phase 1 showed agreement in ICP changes for both sensors during jugular compression and releasing, with a positive and strong Spearman correlation (r = 0.829, P < .001). Phase 2 started after inversion of the sensors in the burr holes; there was a positive and moderately weak Spearman correlation (r = 0.262, P < .001). For phase 3, the sensors were returned to the first burr holes; the prototype behaved similarly to the reference sensor, presenting a positive and moderately strong Spearman correlation (r = 0.669, P < .001).

CONCLUSION: A Wi-Fi ICP monitoring system was demonstrated in a comprehensive and feasible way. It was possible to observe, using smartphone, an adequate correlation regarding ICP variations. Further adaptations are already being developed.

Telemetry in intracranial pressure monitoring: sensor survival and drift

Acta Neurochirurgica (2018) 160:21372144

Telemetric intracranial pressure (ICP) monitoring enable long-term ICP monitoring on patients during normal day activities and may accordingly be of use during evaluation and treatment of complicated ICP disorders. However, the benefits of such equipment depend strongly on the validity of the recordings and how often the telemetric sensor needs to be re-implanted. This study investigates the clinical and technical sensor survival time and drift of the telemetric ICP sensor: Raumedic Neurovent-P-tel.

Methods Implanted telemetric ICP sensors in the period from January 2011 to December 2017 were identified, and medical records reviewed for complications, explantation reasons, and parameters relevant for determining clinical and technical sensor survival time. Explanted sensors were tested in an experimental setup to study baseline drift.

Results In total, implantation of 119 sensors were identified. Five sensors (4.2%) were explanted due to skin dResultsamage, three (2.5%) due to wound infection, and two (1.7%) due to ethylene oxide allergy. No other complications were observed. The median clinical sensor survival time was 208 days (95% CI 150–382). The median technical sensor survival time was 556 days (95% CI 382–605). Explanted sensors had a median baseline drift of 2.5 mmHg (IQR 2.0–5.5).

Conclusion In most cases, the ICP sensor provides reliable measurements beyond the approved implantation time of 90 days. Thus, the sensor should not be routinely removed after this period, if ICP monitoring is still indicated. However, some sensors showed technical malfunction prior to the CE-approval, underlining that caution should always be taken when analyzing telemetric ICP curves.

 

New Telemetric Intracranial Pressure-Monitoring System

Neurosurgery 70[ONS Suppl 1]:ons44–ons49, 2012 DOI: 10.1227/NEU.0b013e31822dda12 

The knowledge of intracranial pressure (ICP) is the basis of an appropriate neurosurgical treatment. Because clinical, fundoscopic, or radiological data alone are often elusive, a pre- or postoperative long-term monitoring of the ICP itself is desirable.

OBJECTIVE: We describe the first clinical experiences with a new telemetric ICPmonitoring device.

METHODS: The transducer of this telemetric intraparenchymal pressure probe is placed under the galea over the calvaria. ICP can be monitored via a special telemetric reader, placed over the intact skin, and the ICP values are stored in a small portable computer. The system does not require an intensive care environment and can be used in any ward or even at home. The system was successfully applied in 10 patients (age, 3- 56 years) in whom raised ICP due to hydrocephalus, shunt dysfunction, endoscopic third ventriculostomy failure, craniostenosis, or pseudotumor cerebri was suspected.

RESULTS: Continuous telemetric monitoring of ICP was performed for 2 to 24 weeks. In 7 patients, increased ICP values could be excluded, and further surgical maneuvers were avoided. In 3 patients, repeated plateaus or continuously raised ICP indicated surgery resulting in a normalization of ICP.

CONCLUSION: This new telemetric system was safe and effective for ICP measurement over a long period, including home monitoring. For the patients, it was easy to handle, and reliable data could be recorded over many weeks. Based on this preliminary experience, the authors consider the new system extremely advantageous in surgical decision making in particularly difficult cases of suspected abnormalities of ICP.