[Recurrent cases of chronic subdural hematoma--its clinical review and serial CT findings].

Eighty-eight cases (114 hematomas) of chronic subdural hematoma (SDH) were treated surgically using irrigation with or without drainage. 13 cases (14.8%), 13 hematomas (11.4%) showed recurrence after the 1st operation. They were compared with non-recurrent cases using clinical reviews and serial CT findings. The result of the study showed that all of the patients in whom recurrence occurred were male and elderly (mean age 70.4 years). Many of these recurrences occurred in cases of bilateral SDH, on the left hematoma side, and at intervals within 7 days from the onset of clinical symptoms after the 1st operation. All recurrent cases were treated surgically using irrigation without drainage. In preoperative CT findings, it was shown that high density areas and small-sized hematomas were detected at a slightly higher rate in recurrent cases than in non recurrent cases. In postoperative CT findings, it was shown that many of the recurrent patients deteriorated during an interval from 2 weeks to 2 months. It was shown that non-recurrent patients had become almost normal by 3 months after the operation. Residual air volume into the subdural space within 7 days in recurrent cases was greater than in non-recurrent cases. Therefore, using irrigation with drainage, planning the operative timing, and reduction of residual air volume into subdural space are proposed as suitable means to avoid recurrence of SDH. Patients of SDH need postoperative follow-up during an interval up to 3 months.