[Perforations of the dura mater during epidural anesthesia. The value of epidurography].

The authors propose a pathogenic classification of perforations of the dura mater occurring during continuous epidural anaesthesia: according to the flow through the communication with the subarochnoid space. Two clinical forms of anaesthesia affecting the cord itself may be distinguished on this basis, one frequent and of immediate onset, diagnosed by the "test dose" and the other rare, of delayed onset, where this safety measure does not suffice. Routine prior epidurography is suggested, in order to ensure the diagnosis of dura mater perforation. In the case of the latter, it show either a more or less typical appearance of radicolography only or, more rarely, a picture which combines opacification of the epidural space with the subarachnoid passage of the contrast medium. This "mixed" appearance, although rare, should be known since it makes it possible to prevent delayed total spinal anaesthesia.