Changes in Intracranial Morphology, Regional Cerebral Water Content and Vital Physiological Variables during Epidural Bleeding

Abstract

Epidural bleeding was produced in 8 anaesthetised and heparinised dogs by an artificial system. Changes in vital physiological variables were related to intracranial shifts and tissue water content assessed with MR imaging. Six animals survived while 2 succumbed. In the surviving animals intracranial shifts and compressions remained unchanged from an early stage. The cerebral perfusion pressure was reduced from between 80 and 110 mm Hg to between 40 and 60 mm Hg. Some increase in supratentorial white matter tissue water was observed. In the lethal experiments cerebral perfusion pressure fell to less than 40 mm Hg. Moreover, secondary delayed anatomical changes were seen including hydrocephalus. Increase in cerebral tissue water was more intense and widespread than in the survivors. These findings indicate that the outcome of epidural bleeding is related to cerebral perfusion pressure with secondary deterioration resulting from additional volume loading from increased tissue water and hydrocephalus.

Experimental epidural hematoma causes cerebral infarction and activates neocortical glial and neuronal genesis in adult guinea pigs

“…As elaborated in the introductory paragraphs, previous animal studies have shown that experimental EDH can induce brain image changes in dogs, swine, and rabbits similar to that seen in human cases (Bergström et al, 1986; Ganz and Zwetnow, 1990; Ganz et al, 1993; Thuomas et al, 1993; Douzinas et al, 1999; Zwetnow et al, 2003). There are also data from rats and cats suggesting that experimental EDH can cause early cellular stress, tissue necrosis, and neuronal and glial degeneration in the compressed cerebral cortex (Xu et al, 1993; Balikci et al, 2008).…”

“…Previous studies in dogs and swine indicate that the extent of dura detachment and epidural shunt may determine the expansion of EDH, providing an explanation for the variability and severity of the lesion in the clinic (Ganz and Zwetnow, 1990; Zwetnow et al, 2003). MRI studies in dogs show that epidural bleeding causes cerebral compression, brain tissue displacement, and water retention (Bergström et al, 1986; Ganz et al, 1993; Thuomas et al, 1993). Imaging studies in rabbits show brain eigenfrequency shifting to lower values as 0.1–0.2 ml of autologous blood is introduced into an epidural balloon, whereas a larger volume of blood results in eigenfrequency shifting to higher values (Douzinas et al, 1999).…”