Pathogenetic factors in chronic subdural haematoma and causes of recurrence after drainage

The radiological aspect, pathology, treatment and results of 132 subdural haematomas observed in 100 patients, are discussed. The majority of these cases were characterized by a nonhomogenous CT scan picture, resulting from repeated bleeding in a previous subdural haematoma evolving to chronicity, or in a pre-existent subdural hygroma. Taking aspirin may have constituted a predisposing factor in 16% of our patients, whilst coagulation disturbances, including anticoagulant treatment, were observed in another 6%; ethylism was present in 11%. A traumatic origin was ascertained in 80% of the patients. The treatment consisted of burr hole evacuation and drainage in 91.5% of the haematomas, corresponding to 92% of the patients; it was eventually repeated once or twice in some cases. In 6% of the patients, a subduro-peritoneal drainage had to be placed ultimately and in 2%, a membranectomy had to be performed because the haematoma had become nearly completely fibrous. The necessity for repeated evacuation and eventual subduro-peritoneal drainage seems to depend mainly on a slow brain re-expansion in some elderly people, who are actually more frequently referred. Two patients died; one was deeply comatose and another in poor general condition. Morbidity in the 96 remaining patients, 2 being lost to follow-up, was 11%: 5% related to the haematoma or to the causal trauma, and 6% from other concomitant neurological disease. The functional result was satisfactory in 85%.