The treatment of the dura mater.
When the dura has not been injured during the process of exposure, pulsating freely, and presenting a normal appearance, preparations can be made to close in or protect the gap in the skull.
When the membrane bulges outwards, and when, in other respects, the indications point to an increase of intradural pressure, the dura must be incised in a crucial manner, and further investigation carried out in the search for a subdural hæmatoma, arachnoid cyst, or other lesion. A hæmatoma is washed out and drained, an arachnoid cyst shelled out or treated by excision of the parietal wall (see [p. 204]).
When the dura is thickened, matted, and adherent to the brain, it is picked up at the least adherent part and carefully dissected away, exposing the pia-arachnoid region. The surface of the brain being so brought into view, the scalpel and dissecting forceps may be required to remove all tags and shreds of matted tissues, this process being continued till a reasonably healthy region has been brought into view.
The treatment of a cortical scar.
There is no reason why a superficial scar should not be freely removed, but, unfortunately, this procedure is necessarily followed by the formation of another scar, at least as extensive as the original fibroid condition. The removal of cortical scars has therefore justifiably fallen into disrepute, and most surgeons content themselves with an exposure of the pia-arachnoid region, the actual cerebral substance being left intact. All bleeding must be arrested, blood extravasation merely favouring the formation of fresh adhesions.
The prevention of fresh adhesions between the dura and the brain and between the scalp and the dura or brain.
‘It is useless to talk about the prevention of fresh adhesions; they form in spite of anything that may be done’ (English). With this statement, I am in complete accord. It has been recommended that fresh egg-albumen, gutta-percha tissue, silver foil, &c., should be inserted beneath the dura or between the scalp and the brain. Experience shows, however, that all these substances are useless, being invaded or surrounded by granulation tissue, and, later on, absorbed by or enclosed in dense fibrous tissue.
The formation of adhesions between the scalp and the dura or brain can, however, be effectually prevented by the insertion of plates, &c. (see [below]).