Posterior Fossa Intracranial Pressure (ICP) Measurement: Clinical Study

In modern medicine, doctors attempt to monitor all physiological variables to assess their evolution and to decide, based on their changes, the therapeutic attitudes to adopt. Furthermore, this helps to establish a forecast of the evolution to be expected.

The measurement of Intracranial Pressure (ICP) has become indispensable for managing brain pathology at the anterior and middle fossa level. Doctors generally carry out this measurement at the frontal level. However, experimental and clinical studies have shown that supra-tentorial ICP measurement does not precisely predict the ICP situation in the posterior fossa.

The increased ICP in the posterior fossa is directly responsible for the clinical deterioration and eventual death in patients with tumour, hemorrhagic, or ischemic pathology of the posterior fossa structures. Some of these lesions are treatable, and their effects reversible if the increase in ICP in the posterior fossa is controlled by pharmacological or even surgical means, preventing it from reaching high levels. This need for on-time ICP control is genuine in the cerebellar hemispheres' lesions, not so much in lesions involving the brainstem. Therefore, the increase in ICP in the posterior fossa needs to be known and documented to facilitate decision-making regarding the therapy to be adopted, be it medical or surgical.

It is known what the abnormal ICP levels are at the supratentorial level, but what is not known whether these same levels apply to the posterior fossa. In other words, what it is not know with certainty is whether the same levels of ICP in the posterior fossa and its elevation during the same time are going to have equally pernicious effects or these effects are greater or lesser. Doctors need to have tables of ICP values in the posterior fossa to help them decide when these values are in the physiological range. When posterior fossa intracranial pressure lye in the pathological range, and patients need pharmacological treatment or surgical decompression, knowing for sure the posterior fossa ICP is essential. Finally, when doctors also need to know when any therapeutic attempt is useless.

Currently, doctors only monitor the ICP at the supra-tentorial level and deduce the changes in the posterior fossa from the CT and MRI images, that is, the size of the lesions, the occlusion of the cisterns, the internal cerebral hernias (cerebellar tonsils, trans-tentorial hernia from bottom to top). However, doctors do not have a tool that can objectify the pathophysiological situation of the posterior fossa's structures in real-time.

Monitoring the posterior fossa ICP will help doctors in decision-making in patients with traumatic, hemorrhagic, ischemic, or tumour pathologies (in the latter case, in the postoperative period of posterior fossa tumours). This posterior fossa ICP measurement will lead to improvements in morbidity/mortality in this subgroup of patients.