Physiopathology and a new treatment of chronic subdural hematoma in children.

Chronic collections of fluid in the subdural spaces may result from trauma or may complicate meningitis. The etiological factor, or factors, which contribute to chronicity of subdural fluid in children remains obscure. We postulate that one possible mechanism is the progressive stretching and narrowing of the cortical veins, bridging the subarachnoid and subdural spaces to enter the superior sagittal sinus. This process ultimately leads to thrombosis of these 'hanging veins'. Narrowing and angulation of these veins could result in elevated back pressure favoring the formation of a transudate. 16 children who had progressive and persistent collections of xanthochromic fluid in the subdural spaces secondary to trauma or infection who were treated previously either with subdural tap, burr holes, subdural peritoneal shunt, craniotomy, stripping of membranes and/or a combination of these, were treated by lowering and advancing the superior sagittal sinus with its overlying sagittal suture and performing a duraplasty. This new surgical technique is directed to improve venous drainage from the superior anastomotic vein into the superior sagittal sinus. Angiographic follow-up showed that only 2 patients still have evidence of fluid collection: the rest of the patients showed normal arterial phases, the medullary system was minimally filled and all of these showed remarkable improvement of the venous drainage throughout the superficial cortical veins with no evidence of hanging veins. Intellectual development of these children following lowering of the superior sagittal sinus showed that 8 patients (50%) were normal or above normal; 5 patients (31.2%) were retarded and 3 patients (18.7%) were borderline.