[Post-traumatic subdural hygroma].

Post-traumatic subdural hygromas, or hydromas, are collections of fluid most often caused by severe head injuries. They present from the onset as hypodense pictures on computerized axial tomography scan (CAT-scan). CAT-scan is the best way to diagnose and to follow the evolution of hygromas. Out of 3002 patients admitted for head injuries, the authors have collected 70 cases of hygromas. 24 of these 70 patients underwent burrhole evacuation of the hygroma. The other 46 had conservative treatment. In both groups, the clinical picture, at short or long-term follow up, was more influenced by the associated brain injuries (extra- or subdural hematomas, cerebral contusion) than by the evolution of the hygroma itself. The surgical treatment of the hygroma was seldom followed by a significant improvement in the patients' condition. As the size of hygromas usually diminishes spontaneously, it seems appropriate most of the time to treat them conservatively and to follow them by CAT-scan, according to the clinical picture.