During a 4 1/2-year period, seven patients with delayed onset of an extradural hematoma were seen among 80 consecutively treated cases of extradural hematoma for a frequency of 8.75%. The hematomas were insignificant or not present on initial computerized tomography (CT) scanning. Repeat CT scans within 24 hours of admission showed sizeable hemorrhages. Six hematomas were evacuated, and one was reabsorbed spontaneously. In only one patient did neurological deterioration herald the onset of the extradural hematoma, four patients remained unchanged, and two improved before diagnosis. Intracranial pressure (ICP) was monitored in five patients, four of whom showed intermittent rise in pressure despite preventive treatment. Intracranial hypotension and rapid recovery from peripheral vascular collapse seemed to be contributory factors in the delayed onset of an extradural hematoma. Awareness of this entity, a high degree of vigilance, ICP monitoring, and repeat CT scanning within 24 hours of injury are strongly recommended in these cases, especially after decompression by either surgical or medical means, recovery from shock, or whenever there is evidence of even minimal bleeding under a skull fracture on the initial CT scan.

No abstract

Globular single meningiomas are generally regarded as benign tumors that can be completely removed. Nevertheless, after a total macroscopic resection including the insertion zone (Grade 1 operation according to Simpson's classification), the incidence of recurrence ranged from 9% to 14% at the 5-year follow-up review. The authors have shown that single meningiomas represent only the visible predominant growth in the midst of a wide neoplastic field in the dura mater. Regional multiplicity in meningiomas would thus seem to be the rule. With this in mind, the authors propose to divide recurrences after Grade 1 operations into true local and false regional. A local recurrence is defined as a regrowth within the limits of the previous dural flap. Regional recurrence is when new growth develops outside the previous craniotomy site; this should not be considered as a recurrence but as a new primary site. These regional recurrences might explain some unexpected late tumor growth occurring after a Grade 1 operation. Five illustrative cases in which regional recurrence was detected by computerized tomography are presented. The authors also propose to add a supplementary grade to Simpson's surgical grading: Grade 0. This operation would entail a wide resection of the dura around the attachment zone of the meningioma. The authors hope that with a Grade 0 operation the incidence of recurrence might be reduced.

According to the accepted theoretical exp]anation of HUND'S ru]e the e]ectronic interaction energy is smallest in the ground state which is of the highest multiplieity. A breakdown of the total energy into one-and two-electron contributions in the case of carbon atom based on self-consistent field calcu]ations and configuration interaction treatment shows that this assumption is not valid. Aceording to our results the main differences in the energies of different terms arising from the same electronic configuration are due to differences in the one-electron energies.

A case of lumbosacral extradural myxopapillary ependymoma is reported. The clinical, embryologic, and therapeutic features of this rare lesion are presented. The unusual entity is discussed in the light of previous experience with extradural ependymoma in the lumbosacral region.