Lesions of the brain stem and related disorders of autonomous regulation systems have been the "Leitmotiv" of the scientific work in the Neurosurgical Department of the Giessen University under the leadership of the late Professor Hans Werner Pia. Some of the results have already been published in supplement volumes of Acta Neurochirurgica. The first one of these was Vol. 4 with the monograph written by H. W. Pia on "Die Schadigungen des Hirnstammes bei den raumfordernden Prozessen des Gehirns". Vol. 19 deals with central disorders of temperature regulation, written by G. Lausberg, followed by Vol. 20 with R. Lorenz's monograph on the effects of intracranial space-occupying lesions on blood pressure and heart rate. Shortly before his death Hans Werner Pia had asked me to combine and publish in this series of supplement volumes of Acta Neurochirurgica another five papers by his co-workers, also related to brain stem lesions and also to cerebral blood flow and CSF dynamics. The result is this volume which contains work dealing with the CT -findings of cerebral mass displacements and their clinical correlations (Sch6nmayr), with other lesions of the brain stem (Laun), with the blink reflex and acoustic evoked potentials in brain stem lesions (Klug and Csecsei), with blood flow in brain structures during increased ICP (Zierski) and with the description of a mathematical model for analysis and simulation of the haemodynamics of intracranial CSF (Hoffmann).

Inhalt
Cerebral Mass Displacements. Part I: Cisternal Hernia in Intracranial Tumours in the Computer Tomogram.- Materials and Methods.- Results.- Influence of Tumour Location on Alterations of the Cisterns.- 1. Tumours of the Frontal Lobe.- 2. Tumours of the Temporal Lobe.- 3. Tumours of the Parietal Lobe.- 4. Tumours of the Occipital Lobe.- 5. Tumours of the Basal Ganglia.- 6. Tumours of the Posterior Cranial Fossa.- 7. Occlusive Hydrocephalus.- Discussion.- References.- Cerebral Mass Displacements. Part II: Clinical Findings in Primary and Secondary Brain Stem Lesions.- Patients and Methods.- Results.- 1. Individual Parameters and Their Combinations.- 2. Progress Investigations.- 3. Summary.- Discussion.- References.- Acute Direct and Indirect Lesions of the Brain Stem CT Findings and Their Clinical Evaluation.- Summary.- Material and Methods.- Results.- 1. Supratentorial Lesions.- 2. Infratentorial Lesions.- 3. Direct Changes in the Brain Stem.- 4. Indirect Secondary Infarcts of the Brain Stem and Other Regions.- Discussion of the Indirect Secondary Infarcts.- References.- Electrically Elicited Blink Reflex and Early Acoustic Evoked Potentials in Circumscribed and Diffuse Brain Stem Lesions.- 1. Introduction and Objectives.- 2. Historical Review.- 3. Materials and Methods.- 4. Results.- 5. Summary.- References.- Blood Flow in Brain Structures During Increased ICP.- Summary.- Material and Methods.- 1. Blood Flow Measurement.- 2. Experimental Protocol.- Results.- 1. Control Values.- 2. Effect of ICP upon Systemic Measurements.- 3. Macroscopic Changes.- 4. rCBF in the Initial Phase of ICP Increase.- 5. Effect of ICP upon Regional CBF.- 6. Influence of ABP.- Discussion.- Acknowledgements.- References.- Biomathematics of Intracranial CSF and Haemodynamics. Simulation andAnalysis with the Aid of a Mathematical Model.- Summary.- Model Equations.- 1. Intracranial System.- 2. Cardiovascular Components.- 3. Baroreceptor Feedback Control.- 4. Disturbance of Central Regulation.- 5. Space Occupying Lesions.- Stability, Model Validation and Simulation Technique.- Model Applications.- 1. Intracranial Pulse Pressure Relationship and Haemodynamics.- 2. Volume Pressure Test and Haemodynamics.- 3. Parameter Estimation.- 4. Rhythmic Phenomena.- Discussion.- References.