Plasma Dynamics

Contains research objectives and summary of research on eighteen research projects split into seven sections and reports on four research projects.U.S. Atomic Energy Commission (Contract AT(l1-1)-3070)National Science Foundation (Grant GK-37979X1

Microsurgery can cure most intracranial dural arteriovenous fistulae of the sinus and non-sinus type

There is consensus that intracranial dural arteriovenous fistulae (dAVF) with direct (non-sinus-type) or indirect (sinus-type) retrograde filling of a leptomeningeal vein should be treated due to the high risk of neurological deficits and hemorrhage. No consensus exists on treatment modality (surgery and/or embolization) and, if surgery is performed, on the best surgical strategy. This series aims to evaluate the role of surgery in the management of aggressive dAVFs. Forty-two patients underwent surgery. Opening and packing the sinus with thrombogenic material was performed in 9 of the 12 sinus-type dAVFs. In two sinus-type fistulae of the cavernous sinus and 1 of the torcular, microsurgery was used as prerequisite for subsequent embolization by providing access to the sinus. In the 30 non-sinus-type dAVFs, surgery consisted of interruption of the draining vein at the intradural entry point. In 41 patients undergoing 43 operations, elimination of the dAVF was achieved (97.6%). In one case, a minimal venous drainage persisted after surgery. The transient surgical morbidity was 11.9% (n = 5) and the permanent surgical morbidity 7.1% (n = 3). Our surgical strategy was to focus on the arterialized leptomeningeal vein in the non-sinus-type and on the arterialized sinus segment in the sinus-type dAVFs allowing us to obliterate all but one dAVF with a low morbidity rate. We therefore propose that microsurgery should be considered early in the treatment of both types of aggressive dAVFs. In selected cases of cavernous sinus dAVFs, the role of microsurgery is reduced to that of an adjunct to endovascular therapy

Dural Cavernous Angioma of The Posterior Sagittal Sinus: Case Report.

BACKGROUND: Extraaxial cavernous hemangiomas (cavernomas) are very rare lesions, and less than 20 descriptions of these lesions outside the middle fossa have been reported. In this report, we describe a dural cavernous angioma involving the posterior sagittal sinus and discuss the clinical, radiological, operative, and histological features of this very uncommon lesion. CASE DESCRIPTION: A 31-year-old right-handed male presented with headache and decreasing visual acuity. Severe bilateral papilledema was found on fundoscopic examination. Neurological examination demonstrated a minor right temporal field cut. Brain magnetic resonance imaging with contrast demonstrated a 2.5 x 2.5 cm hyperintense enhancing mass in the midline, which was contiguous with the posterior margin of the falx cerebri. The patient underwent a bilateral occipital craniotomy centered on the lesion. The histological features were consistent with cavernous angioma. CONCLUSION: This report demonstrates that although extra axial cavernomas are quite rare, they must be included in the differential diagnosis of enhancing lesions along the posterior sagittal sinus. The operative removal of these lesions can be quite treacherous and usually requires a careful reapproximation of the patent sinus after lesion excision

Patient Transport and Brain Oxygen in Comatose Patients

Abstract OBJECTIVE Transport of critically ill intensive care unit patients may be hazardous. We examined whether brain oxygen (brain tissue oxygen partial pressure [PbtO2]) is influenced by transport to and from a follow-up head computed tomography (transport head computed tomography [tHCT]) scan. METHODS Forty-five patients (24 men, 21 women; Glasgow Coma Scale score ≤8; mean age, 47.3 ± 19.0 years) who had a traumatic brain injury (n = 26) or subarachnoid hemorrhage (n = 19) were retrospectively identified from a prospective observational cohort of PbtO2 monitoring in a neurosurgical intensive care unit at a university-based level I trauma center. PbtO2, intracranial pressure, and cerebral perfusion pressure were monitored continuously and compared during the 3 hours before and after 100 tHCT scans. RESULTS The mean PbtO2 before and after the tHCT scans for all 100 scans was 37.9 ± 19.8 mm Hg and 33.9 ± 17.2 mm Hg, respectively (P = .0001). A decrease in PbtO2 (>5%) occurred after 54 tHCTs (54%) and in 36 patients (80%). In instances in which a decrease occurred, the average decrease in mean, minimum, and maximum PbtO2 was 23.6%, 29%, and 18.1%, respectively. This decrease was greater when PbtO2 was compromised (<25 mm Hg) before tHCT. An episode of brain hypoxia (<15 mm Hg) was identified in the 3 hours before tHCT in 9 and after tHCT in 19 instances. On average, an episode of brain hypoxia was 46.6 ± 16.0 (standard error) minutes longer after tHCT than before tHCT (P = .008). Multivariate analysis suggests that changes in lung function (PaO2/fraction of inspired oxygen [FiO2] ratio) may account for the reduced PbtO2 after tHCT (parameter estimate 0.45, 95% confidence interval: 0.024–0.871; P = .04). CONCLUSION These data suggest that transport to and from the intensive care unit may adversely affect PbtO2. This deleterious effect is greater when PbtO2 is already compromised and may be associated with lung function