On the rupture of an aneurysm.

The intracranial aneurysm, with an estimated occurrence of up to 4% in the general population, belongs among the most dangerous of cerebrovascular diseases. Although less than one-fifth of these cases results in a subarachnoid haemorrhage, the resulting disability and mortality rate is too high. More understanding is needed regarding aneurysm rupture and its deleterious effects. This study presents a physiologically-feasible explanation for the development of an enormous haemodynamic stress in the vicinity of the aneurysm in the cerebrovascular bed. Using a computer circulation model, this build-up of pressure was developed by sequentially imposing a series of interventions on the normal system.

The role of anastomoses in brain circulation.

Anastomoses in the arterial system of brain investigated on the computer model can be divided into three basic groups. Parasitical anastomoses diverting blood into affected regions and stealing it from the unaffected parts, compensating anastomoses delivering blood from extracranial sources, and redundant anastomoses protected the vital parts of the brain.

[The function of the fluid compartment. Part I]. / Zur Funktion des Liquorraumes. Teil I.

Expansion of the cerebrospinal-fluid space is a new conception introduced in view of the fact that in the closed cranial cavity in case of an increase in cerebrospinal fluid the relation volume/pressure undergoes characteristic changes. The physical laws resulting from this have already been considered in the Monro-Kellie doctrine and concern the three main parts of the cranial cavity: brain, cerebrospinal fluid, and vessels. The capability of compensation, the compliance and the elasticity or elastantia of the cerebrospinal-fluid space can be measured on the basis of the dynamic changes proceeding in the space, the pressure/volume index (PVI) being a measure of the degree of filling of the intracranial space.