Continuous peroperative supraoccipital cisternal drainage.

1. The technique of continuous peroperative supraoccipital cisternal drainage for intracranial decompression by means of a slow and progressive removal of CSF from the ventricles and the basal cisterns is described. 2. This procedure was used in eight patients with good results, considerable decompression being obtained with no untoward effects. 3. In four cases of intracranial aneurysm marked intracranial hypotension was obtained, greatly facilitating treatment of the lesions. 4. In four cases of brain tumour, the reduction of intracranial hypertension was not so great, and was complemented with general antihypertensive treatment. 5. Supraoccipital cisternal drainage removes intracranial CSF, but not the fluid in the spinal theca. The tonsils of the cerebellum are thus kept floating, and this, in our experience, has prevented them from impacting in the foramen magnum and compressing the medulla,