Extradural Hematoma of the Posterior Fossa

EXTRADURAL henia toina confined to the posterior fossa, the so-called extradural cerebellar hematoma, is a rare clinical entity. As a rule this lesion has been overlooked because of the paucity of neurologic signs and symptoms or diagnosed so late that operation was of no avail. To date we have found only seven such cases in the literature which were diagnosed and successfully operated upon. Another case which was cured is reported here, and a discussion of the anatomic basis of one of its interesting neurologic findings is presented. The scarcity of extradural hematomns limited to the posterior fossa is apparent when several large series of head injuries with extradural hemorrhage are examined.% 1 0 , 12. 1% 1% 1% 16. 19 Of a total of 367 cases there were only two patients in whom the lesion was found confined to the posterior fossa, an incidence of 0.5 per cent of all extradural hemorrhages. One of these was presented by McKenzieI3 and is believed to be the first case of extradural cerebellar hematoma reported in the literature. The second case was noted by Munro and Maltby." In both instances the patients succumbed and the clot was found at postmortem examination. Isolated cases in which this lesion was found, operated upon and the clot successfully removed have been reported by Anderson,' Coleman and Thomson,' Kessel," Scoville," Turnbull'" and A case reported by Fleminger and Smith,: which has previously been overlooked in reviewing the subject, should be included in this group. The latter was reported as a case of acholasia of the esophagus following depressed fracture of the base of the skull. In addition, the patient exhibited a modified Collet's syndrome, and a t operation an extradural hematoma of the posterior fossa was found. The clot was evacuated, and the patient recovered completely after a prolonged convalescence.