Occurrence of Spontaneous Cortical Spreading Depression Is Increased by Blood Constituents and Impairs Neurological Recovery after Subdural Hematoma in Rats.

Acute subdural hemorrhage (ASDH) is common and associated with severe morbidity and mortality. To date, the role of spontaneous cortical spreading depression (sCSD) in exaggerating secondary injury after ASDH, is poorly understood. The present study contains two experimental groups: First, we investigated and characterized the occurrence of sCSD after subdural blood infusion (300 μL) via tissue impedance (IMP) measurement in a rat model. Second, we compared the occurrence and influence of sCSD on lesion growth and neurological deficit in the presence and absence of whole blood constituents. In the first experimental group, three IMP traits could be distinguished after ASDH: no sCSD, recurrent sCSD, and constant elevated IMP (anoxic depolarization [AD]). In the second experimental group, sCSD occurred more often after autologous blood, compared with paraffin oil infusion. Lesion volume 7 days post-ASDH was 27.3 ± 6.8 mm3 after blood and 3.4 ± 2.1 mm3 after paraffin oil infusion. Subgroup analysis showed larger lesion size in animals with sCSD, than in those without. Further, occurrence of sCSD led to worse neurological outcomes in both groups. sCSD occurs early after ASDH and does not depend on the presence of whole blood constituents. However, numbers and degree of sCSD are more frequent and severe after autologous blood infusion, compared with an inert volume substance. The occurrence of sCSD leads to lesion growth and worse neurological outcome. Thus, our data advocate close monitoring and targeted treatment of sCSD after ASDH evacuation.