[Endoscopic findings in chronic subdural hematoma].

On the genesis of chronic subdural hematoma (CSH), it is one of the possible explanations that a head injury triggers uncertain cause off for the formation of the hematoma membrane, where the bleeding occurs to form and enlarge the hematoma. Although some reports on the staging classification based on computed tomography (CT) findings are available the natural course or history of the hematoma formation is not yet known. As previously reported, we have been using an endoscopically guided method in which a drainage tube is placed in the most frontal area of the cavity so as to evacuate the residual air efficiently. In this study, we analyzed the endoscopic findings in hematoma cavities and compared them with the clinical data, focusing on the post-trauma interval and recurrence of the hematoma. Between January 1999 and October 2000, we had an opportunity to observe the inner aspect of 60 hematomas in 48 patients. A trabecular structure was found in 39 hematoma cavities (65%), whereas apparent clot formation was observed in 18 cavities (30%). Septum formation leading to a multi-loculated hematoma was observed in 10 cavities (17%). Twenty-six patients with 32 hematomas with the obvious history of head injury were classified into 4 groups according to the post-traumatic interval to the surgery, which are stage I; less than 30 days, stage II; 31 to 60 days, stage III; 61 to 90 days and stage IV; more than 91 days. Clot formation and a trabecular structure were frequently seen in stages II and III. Clot formation was statistically and significantly seen in the recurrent group. The results suggest that CSHs increase in size in stages II and III, when clot formation and a trabecular structure are frequently observed. Endoscopic observation of hematomas may assist to know hematomas, and clot formation may be a warning of hematoma recurrence.