[Pathogenesis of persistent subdural effusions in infants (author's transl)].

Current theories on the pathogenesis of persistent subdural effusions in infants are not supported by our clinical and operative data. In our more recent cases, a daily electrophoretic analysis of the fluid obtained by external subdural drainage has been performed and allowed to disclose the presence or progressive appearance of cerebro-spinal fluid. The relative concentrations, observed for some proteins present in the fluid collected in this way, cannot be explained by simple filtration, but enforces us to postulate the existence of a free communication between the subarachnoid and the subdural spaces. These first results support our initial hypothesis assuming that persistent effusions are supplied and even replaced by cerebro-spinal fluid, due to the occurrence of a communicating hydrocephalus ruptured in the subdural space. There is thus no sound physiopathological basis for treating these cases with membranectomy and we suggest instead that the treatment of choice should be a fluid derivation.