This 13th volume of Advances in Neurosurgery presents thos.e papers held at the 35th Annual Meeting of the German Society of Neurosurgery in Hannover, June 13-16, 1984. Of 150 papers submitted, the program com mittee of the Society chose 69 for presentation. I would like to thank Professors Bock, Brock, Jensen, Wenker, and Wlillenweber for their as sistance in the selection. It was the intention of the President of the Congress at this meeting to lay special scientific emphasis on discussion. For this reason the number of papers had to be limited even more than usual in order to give all participants the opportunity for questions and the presenta tion of their own experience. The main topic of the first day was Extra-Intracranial Anastomoses. Here the operative experience and the long-term results of these operations in the German-speaking countries were reviewed. This discussion was preceded a day earlier by a satellite symposium on the possibilities of the prophylaxis and treatment of ischemic neurological deficits fol lowing subarachnoid hemorrhage by means of calcium antagonists. Microsurgery at the Edge of the Tentorium was the second main topic. In co operation with the SOCiety's microneurosurgery working group, only a small number of lectures were planned, but the topic was covered thor oughly in a round-table discussion.

First multi-year cumulation covers six years: 1965-70.

A distinction between primary and secondary brain damage of vari ous origin, particularly in acute lesions, such as head injury and ische mia is not entirely new. The concept is of practical significance, be cause it is the foremost intention of all clinical efforts to prevent, or at least attenuate the development of secondary sequelae. Primary dam age to nervous elements usually cannot be influenced by treatment. Its prevention is the objective of prophylactic measures. The current volume gathered prominent scientists and clinicians from various fields to pro vide a competent introduction and survey of the various aspects involved in secondary brain damage. It was attempted to provide criteria for the distinction between the primary and secondary phenomena on a morpho logical and functional level, on the basis of the kinetics involved and, most importantly, regarding the different specific manifestations, such as disturbances of microcirculation, aspects of the blood-brain barrier, and of cellular structure and function at a molecular level. Although it was not expected that a grand unifying hypothesis will be reached recon cilable with the many, occasionally opposing views on such a complex subject, nevertheless, the present volume attains an appropriate result. It can best be described as a mosaic of many different pieces which only as an ensemble reflect the current state of the art.