Surgical treatment of chronic subdural hematoma in 500 consecutive cases: clinical characteristics, surgical outcome, complications, and recurrence rate.

Chronic subdural hematoma (CSDH) is one of the most common clinical entities in daily neurosurgical practice. The diagnosis and treatment are well established, but recurrence, complications, and factors related to these problems, especially in the elderly, are not completely understood. This study evaluated the clinical features, radiological findings, and surgical results in a large series of the patients treated at the same institution. 500 consecutive patients (359 men and 141 women) with CSDH were treated by burr hole craniostomy with closed system drainage from January 1987 through February 1999. Causes, clinical and computed tomographic findings, surgical results, re-expansion of brain after surgery, and hematoma recurrence were statistically analyzed to elucidate the potential risks of CSDH. Most patients (89.4%) had good recovery, 8.4% showed no change, and 2.2% worsened. Six patients (1.2%) died, three due to disseminated intravascular coagulation. Recurrence of hematoma was recognized in 49 patients (9.8%), at 1 to 8 weeks (3.5 +/- 1.9 weeks) after the first operation. The brain re-expansion rate at one week after operation was 45.0 +/- 21.4% in patients with hematoma recurrence and significantly lower than 55.3 +/- 19.1% in patients without recurrence (p < 0.001). Old age, pre-existing cerebral infarction, and persistence of subdural air after surgery were significantly correlated with poor brain re-expansion (p < 0.001). Twenty-seven patients (5.4%) suffered postoperative complications, of which 13 cases were acute subdural hematoma caused by incomplete hemostasis of the scalp wound and four cases were tension pneumocephalus. Careful hemostasis and complete replacement of subdural hematoma by normal saline to prevent influx of air into the subdural space will further improve the surgical outcome for patients with CSDH.