EXTRADURAL DEAD SPACE FOLLOWING CRANIAL BONE ADVANCEMENT

The extradural dead space produced after enlargement of the intracrani al space or after reduction of the volume of the intracranial contents persists for an unknown period of time. To investigate this further, an extradural dead space was surgically created by advancement of pari etal bones in 9 adult rabbits. By design, there was no connection with the paranasal sinuses. To determine outcome of the dead space, three- dimensional computed tomographic and histological studies were perform ed. The brain volume decreased in the first 3 months after surgery and remained constant for up to 9 months. The extradural volume increased in the first 4 weeks postoperatively, gradually decreasing in size wi th time. The brain failed to eliminate the extradural dead space by re arrangement or expansion. An osseous cavity filled with fluid and conn ective tissue was formed within the dead space. The fluid within it re mained, even 9 months after surgery. This could be a potential environ ment for bacterial invasion if there was a connection with the nasopha rynx.