To review Intracranial EEG findings where Cortical Spreading Depolarization (CSD) was recorded in three    patients using subdural electrocorticography and effectively treated with Ketamine. 

CSD is associated with hyperexcitation of neurons and responsible for the neuronal loss and secondary brain injuries. 

CSD events consisted of slow deflection of voltage in frequency range DC-0.01Hz.  Events were counted if maximum amplitude was > 100 uV and Duration was > 3 min. In addition, the spatial extent of the event was quantified by the number of contacts showing voltage change. ECOG traces were displayed using timebase of 2mm/min and sensitivity of 5 uV/mm. 

Case 1

47-year-old woman who struck head-on a pole for which she was taken to the emergency room. She was intubated and found to have multifocal contusions and left subdural hematoma with midline shift for which she underwent subdural hematoma evacuation via hemicraniectomy with cortical electrode strip placement. CSD events were recorded and effectively treated with IV Ketamine infusion. 

Case 2

82-year-old female was brought to the emergency room for an unwitnessed fall. The patient was found to have a large Right side SDH and underwent emergent craniotomy with SDH evacuation and cortical electrode strip placement. CSD events were recorded and effectively treated with IV Ketamine infusion. 

Case 3

49-year-old man expelled from a bar due to intoxication was found down and obtunded for which he was brought to NSUH ED where he was noted to a left subdural hematoma with brain compression. He was intubated and taken emergently for left decompressive hemicraniectomy with cortical electrode strip placement. CSD events were recorded and resolved without any treatment. 

Cortical electrode strip placement is a useful tool to identify, monitor, and treat CSD events which occurs in about 15 % of the patients following subdural hematoma evacuation.