The current ICP devices can be placed in the epidural, subdural, subarachnoid, parenchymal, or ventricular locations. The ventricular ICP monitoring device has proved to be the most accurate of all of the monitors. This method is done by inserting a catheter through the skull, inside the brain, and down to the brain ventricles. Placing a catheter into the ventricles is called a ventriculostomy. With this device, the ICP can be monitored and CSF can be drained off in an attempt to decrease the ICP.
The subarachnoid screw (bolt) does not penetrate the brain. It has a lower risk of infection than the intraventricular catheter and it is easier to place. However, it cannot drain CSF and it is unreliable at high ICP's. The epidural sensor goes through the skull, but it does not penetrate the dura. It is easy to insert and has a minimal risk for infection. It is unable to drain CSF and the accuracy is questionable.
There are risks to ICP monitoring, as for any invasive procedure. Infection, hemorrhage, obstruction of the catheter or monitoring device, increase in brain swelling, malfunction of the catheter, and overdrainage or collapse of the ventricles are all possible complications. The use of antibiotics, sterile technique, and limited indwelling placement time can all help to avoid and reduce these complications.