Implantable ICP monitor for improved hydrocephalus management.
BACKGROUND
Hydrocephalus patients are commonly treated by insertion of ventriculoperitoneal shunts, but these have high complication rates. Monitoring of shunt and patient condition can be achieved through measuring intracranial pressure (ICP). Significant zero drift has limited previous developments towards a long-term implantable ICP monitor. We present a new implantable solid-state pressure sensor system appropriate for chronic (lifetime) monitoring of ICP.


METHODS
Initial designs of the proposed ICP system were realised and the pressure sensor catheter underwent bench-top tests to analyse its characteristics. A drift rig was constructed for the long-term analysis of the sensor's zero drift. The pressure sensor catheter was used to continuously monitor blood pressure in rats.


RESULTS
Three potential design solutions were realised: a standalone sensor, the sensor unit in line with a shunt system, and the sensor unit fully integrated into the shunt valve housing. Initial stability results across 46 days show a maximum drift of less than 2 mmHg and a minimum drift of less than 0.2 mmHg.


CONCLUSIONS
Initial experience with the new implantable solid-state pressure sensor system confirms its suitability for chronic pressure monitoring. The device is promising for providing vital information on shunt and patient condition.
Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
Ellyce
E
Stehlin
Simon
S
Malpas
Peter
P
Heppner
Patrick
P
Hu
Matthew
M
Lim
David
D
Budgett
D000818:Animals; D004567:Electrodes, Implanted; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology*; D007427:Intracranial Pressure / Q000502:physiology*; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods*; D013686:Telemetry; D014160:Transducers, Pressure