Factors contributing to functional recovery following evacuation of epidural hematoma were analyzed in 53 subjects. Subjects were limited to the cases with "pure" epidural hematoma. Fifty-three cases were classified into 3 groups based on presence or absence, and duration of preaggravation period (PAP) following occurrence of head trauma (Fig. 1). Level of consciousness at operation and at PAP is summarised in Fig. 2. Major neurological signs at operation are summarized in Table 1. Gradings of functional status were divided to 6 (Table 2). Gradings of 53 subjects which were judged 1 month after removal of epidural hematoma are summarized in Fig. 3.
Results: 1) As to outcome in relation to duration of preaggravation period (PAP) and consciousness level at operation (Fig. 4): The patients whose PAP was shorter and whose consciousness level at operation was more severe, took outcome of lower (worse) gradings. 2) As to outcome in relation to interval from the end of PAP to operation and PAP (Fig. 5): The patients whose PAP are within 3 hours, took outcome of relatively good recovery only when epidural hematoma was removed within 5.5 hours after the end of PAP. 3) As to outcome in relation to interval from the end of PAP to operation and consciousness level at operation (Fig. 6): The patients whose consciousness level at operation was better than semicoma took good recovery when epidural hematoma was evacuated within 5.5 hours after the end of PAP. This was right even in the patients who presented with decerebrate posture.(ABSTRACT TRUNCATED AT 250 WORDS)