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).

Historical photograph of spinal anaesthesia In 1884 the American neurologist J. L. eases. His discovery, however, marks the Corning, by blocking the neural con onset of the era of regional anaesthesia. It took almost one hundred years until his duction to the hind extremities of a dog by injecting cocaine-solution into the lumbar original idea of "local medication of the vertebral interspace, was the first to per cord" was again reconsidered due to two form spinal (or epidural?) anaesthesia [1]. reasons: At that time, he was unaware of the local I. The discovery of different drug receptors anaesthetic properties of cocaine (dis in the spinal cord made it possible, by in covered in the same year by C. Koller, who trathecal injection (or epidural appli cation, if the drug penetrates the dura), applied cocaine to the eye of one of his pa tients [3]) and did not intend to introduce to alter nociceptive or motor transmis an anaesthetic procedure. Corning's pri sion within the spinal cord. mary aim was the application of drugs in 2. Implantable devices for long-term appli proximity of the central nervous system, i. e. cation of drugs to specific sites of the spinal cord, in order to treat or even heal body, including the spinal spaces, were developed during the 1970's.

The basic principles of the management of cerebral arteriovenous mal- formations were established during the first phase of the neurological attack on these problems between 1930 and 1960. The leaders were CUSHING, BAILEY and DANDY, but principally OUVECRONA, and in Ger- many TONNIS. The experience gained showed that complete excision of the arteriovenous angioma was the only certain cure, and therefore was the procedure of choice. In the present second phase important advances should be made and indeed are occurring. New diagnostic techniques such as total angio- graphy, selective and superselective angiography, intraoperative and fluorescein angiography, and the EMI-scanner have been developed. The pathophysiological aspects have been further investigated by indirect and direct measurement of local and general cerebral blood flow. Parallel with these developments operative technique itself has been improved and modified by new methods. A more aggressive attitude has been stimulated towards those angiomas, which had to be regarded as inoperable only a few years ago. Among these many im- provements and technical advances include microsurgical techniques, combined stereotactic and microsurgical procedures, artificial emboliza- tion of different kinds and the cryosurgical management. Multiple variables such as the age of the patient, the type, localization, and size of the angioma, its clinical picture and the possible complica- tions, such as hemorrhage have been analysed and are understood better. These factors influence the indication for, and choice of, the appropriate procedure to a great extent.