Ventricular size and chronic increased intracranial venous pressure in the dog

Abstract

✓ Intracranial venous pressure was increased by blocking the torcular Herophili in 10 dogs. At intervals of 1 to 29 weeks, pressure in the superior sagittal sinus and cerebrospinal fluid (CSF) were recorded and the size of the ventricles determined at autopsy. Changes in venous pathways were documented by sinograms. Significant increase in both sagittal sinus and CSF pressures occurred after torcular block. CSF pressures remained elevated for as long as 29 weeks at an average of 100 mm above preblock levels. Neurological deficits after torcular block were minimal. Autopsies showed normal-sized ventricles without any stigmata of hydrocephalus.

Time Course of Intraventricular Pressure Change in a Canine Model of Hydrocephalus: Its Relationship to Sagittal Sinus Elastance

“…even at levels approaching systemic arterial pressure. In an animal model of increased intracranial venous pressure, Guthrie et al [33] reported that although the two pressures were linked, maintenance of a normal pressure gradient persisted. Other authors [34.…”

Hydrocephalus and Elevated Intracranial Venous Pressure

“…All reported cases of elevated venous pressure causing hydrcephalus have been in infants or children who still have a distensible calvarium [6]. Hour and Miller [9] also noted the young age of onset of the dural hypertension of patients who develop hydrocephalus, but they drew no conclusions from this observation.…”

“…The relationship between increased intra cranial venous pressure and hydrocephalus has been the subject of several reports [6,10,12]. Unquestionably, massive direct shunting of arterial blood into the venous system or occlusion of important components of the cephalic venous drainage system can cause increased intracranial venous pressure.…”

“…Elevated intracranial venous pressure probably does not cause hydrocephalus within a rigid skull because any increase in venous pressure is matched by a similar increase in cerebro spinal fluid pressure. Therefore, no disturbance occurs in the cerebrospinal fluid-venous gradient and cerebrospinal fluid absorption continues [6].…”

“…Guthrie et at. [6] blocked the torcular Herophili in 10 adult dogs. Autopsies 1-29 weeks later showed normal-sized ventricles.…”