An analysis of extradural dead space after fronto-orbital surgery.

This study was undertaken to evaluate several concerns regarding the extradural space resulting from elective fronto-orbital advancement or frontal sinus cranialization techniques. The questions are (1) Do infants undergoing these techniques have the potential to obliterate this space at an accelerated rate, e.g., within 1 or 2 days? (2) Do adults have any potential to obliterate the space? (3) Do children obliterate the space like infants or like adults? (4) What is the specific time sequence for dead-space obliteration? Twenty patients ranging in age from 6 months to 35 years were studied before and after fronto-orbital advancement. The patients were divided into three groups: (1) infants (up to 15 months), (2) children (up to 9 years), and (3) adults (9 years and beyond). Postoperative intracranial dead space was assessed by serial CT scans. Ten patients had CT scans more than 14 days after surgery. These data demonstrate that intracranial dead space in infants is obliterated in a delayed fashion. Children tend to obliterate intracranial dead space in a manner similar to that of infants. Adults are able to obliterate the space over a longer, but finite, period of time as compared with infants and children. Part of the mechanism responsible for obliteration of the postoperative space may be enlargement of the ventricular system.