ICP-Monitoring in the Middle Cranial Fossa. A Comparison Between the Intraventricular Method and the Introduction of a Catheter Tip Transducer into the Parasellar Cistern via the Foramen Ovale

Abstract

In cases of brain edema after closed head injuries it is often impossible to puncture the lateral ventricles for the purposes of ICP monitoring. The epidural pressure gives less accurate results depending on baseline shift as Gobiet et al. (1972) found, and difficulties with the coplanar implantation as many investigators published. Another reason lies in the non-homogeneous transmission of increased intracranial pressure within the supratentorial space, as Langfitt et al. (1964) Stated. This forced us to look for another approach. When looking through the “retrospectoscope” as Evans (1972) told us during the First International Symposium on ICP we could not find any paper dealing with intracranial pressure monitoring through the foramen ovale. Based on our own experience with more than 1200 electrocoagulations of the Gasserian ganglion, published by Hensell and Miltz (1974) with the method of Kirschner (1933), todays thermocoagulation and the neuroradiological findings of Hakanson (1979) we tried this route via the foramen ovale into the subarachnoid space of the middle cranial fossa. From our operations in trigeminal neuralgia we knew that sometimes the trigeminal cistern was reached by the Kirschner method as well as with the approach of Hä;rtel. It is well known anatomically and proven by Hakanson (1979), that the trigeminal cistern opens into the subarachnoid space of the posterior fossa. In cases of a normal ICP this location could give useful data, but in patients with raised ICP, in whom a continuous monitoring is indicated, there could be some limitations in the accuracy of posterior fossa ICP, as Langfitt (1964) mentioned. Secondly, the canal from Meckel’s cave into the posterior fossa can be obstructed by brain swelling. In order to avoid these difficulties a catheter tip pressure transducer is pushed forward into the subarachnoid space of the parasellar cistern of the middle cranial fossa. Here a satisfying ICP record can be obtained.