Abstract
Acute traumatic hematoma within the posterior fossa has been considered to be difficult to diagnose in its early stage because of the perplexity of clinical findings and the paucity of localizing signs. For the purpose to obtain the diagnostic criterion in its early stage, clinical findings of 8 cases of acute forms were analysed.
In most cases, the impact was received on the back of the head. Deterioration of consciousness was rapidly progressive in all cases. However lucid intervals within two hours were seen in 5 cases. The most important neurological finding in the early diagnosis was bilateral pyramidal sign which was found in 5 out of 8 cases. Unilateral signs which might mimic the supratentorial hematoma were found in 5 cases; thus 5 cases showed unilateral pyramidal sign, 3 cases showed unilateral mydriasis. Although these unilateral signs might indicate the supratentorial hematoma concomitant with the posterior fossa hematoma, it must be stressed that these signs could be developed by the posterior fossa hematoma only. Posterior fossa skull fractures were recognized by X ray examinations in 6 cases. Carotid angiogram showed findings of internal hydrocephalus in 5 cases. Vertebral angiogram was the most useful diagnostic aid of the posterior fossa hematoma. 7 cases of acute forms and I case of subacute form were correctly diagnosed by this method. It is emphasized that this examination is the procedure of first choice when one is faced with the possibility of the posterior fossa hematoma.
Concerning about the operative results, 5 out of 7 cases operated on died, 70% of mortality rate. However, among 4 cases in which the early diagnosis was possible, only I case was lost.
