Long-term performance of a CE-approved telemetric intracranial pressure monitoring.

Telemetric intracranial pressure (ICP) monitoring has been a challenge throughout several decades. Major obstruction was to minimize zero drift of absolute pressure sensors. A new promising product demonstrating in-vitro excellent long-term stability has been tested for its reliability in an animal model with a follow-up of up to 2 years. In "minipigs" sub-dural (Raumedic-STel®, Helmbrechts Germany) and intraparenchymal (Raumedic-PTel®) telemetric ICP probes have been inserted. Standard ICP probes (Raumedic Neurovent P®) served as controls. In regular intervals of 3 months the telemetrically and conventionally measured ICP have been compared. For each control a new conventional ICP probe has been inserted frontally to the telemetric device in the generalized anesthetized minipigs, resulting in overall 38 comparisons. Bland-Altman-plots, Chi2-tests and matched pair T-tests (significance level < 0.05) were used for data-analysis. The zero-shift was -1.7 ± 7.6 mm Hg (limits of agreement: 4.4 ± 1.9 mm Hg) and -3.0 ± 6.0 mm Hg (limits of agreement: 3.6 ± 2.6 mm Hg) in STel and PTel respectively meeting well the devices specification of ± 2 mm Hg drift per year. The reliability of both telemetric probes has been proved as quite comparable (p=0.2). These new telemetric ICP probes demonstrate reliable data during at least the first 6 months after implantation.