Blister-like supraclinoid internal carotid artery pseudoaneurysm in a 15-year-old male: Case report and review of the literature

With an incidence of less than 1-3 per million, pediatric aneurysms are rare clinical entities. A traumatic etiology is implicated in a large proportion of these cases, leading to the formation of both \u27false\u27 and \u27true\u27 aneurysms. These occur most often in the distal circulation, but have also been described in the supraclinoid distal internal carotid artery (ICA). Blood blister aneurysms are also found in this location; however, they have not been described in the pediatric population. We report the case of a 15-year-old male who presented following cranial trauma with diffuse basal subarachnoid hemorrhage and limited additional intracranial pathology. Computed tomography angiography demonstrated a small, 2-mm blister-like aneurysm arising from the dorsal surface of the left supraclinoid ICA at a non-branching site. Despite early endovascular treatment with Guglielmi detachable coils, the lesion continued to grow over subsequent studies, necessitating open surgical clipping. At the time of surgery, gross pathology of the native ICA was observed, raising the possibility of a preexisting blood-blister aneurysm. We review the epidemiology, pathophysiology and diagnostic considerations of these lesions. The endovascular and surgical management of these complex non-branching supraclinoid ICA aneurysms is also discussed. Copyright © 2012 S. Karger AG, Basel

Quantitation of lymphatic drainage of the central nervous system in sheep

grantor: University of TorontoIn both sheep and rats, multiple lymphatic drainage pathways for cerebrospinal fluid (CSF) exist along the central nervous system (CNS) axis, but a major route involves clearance through the cervical vessels (Boulton et al., 1996; Boulton et al., 1998c). To determine the relative roles of arachnoid villi and lymphatics in the clearance of a CSF tracer we compared the plasma recovery of intraventricularly administered 125I or 131I human serum albumin (HSA) before and after lymphatic interruption. Approximately one half of the protein tracer transported from the CSF compartment into plasma was removed by extracranial lymphatics in both species (Boulton et al., 1997; Boulton et al., 1998c). Nonetheless, tracer recovery studies can be problematic. The transport of a CSF tracer to the plasma complicates measurements of the CSF tracer in lymph since the HSA that was transported from the CSF into plasma by the arachnoid villi would filter back into the lymphatic compartment resulting in an overestimate of the lymphatic contribution to CSF absorption. Arachnoid villi drainage values would also be underestimated. To overcome this problem, we developed a mathematical model that permitted estimates of volumetric CSF absorption into lymphatics using tracer recovery data in sheep. An important element in the design of the model was the ability to correct the recovery data for errors introduced by filtration. Volumetric CSF absorption by extracranial lymphatic vessels was conservatively estimated at 40-48% of the total volume of CSF absorbed from the cranial compartment (Boulton et al., 1998a). Additionally, lymphatic drainage rates of CSF were found to increase with elevations in intracranial pressure (Boulton et al., 1998b).Ph.D