Kenzoh Yada

Hemorrhagic venous infarction after excision of an arteriovenous malformation: case report.

A case of arteriovenous malformation (AVM) in which postoperative hemorrhagic infarction developed, probably because of occlusion of the former draining veins, is reported. The hemorrhage developed in the temporal lobe 3 days after the initial operation and was located in the immediate vicinity of the site of the AVM. The following findings suggest that the postsurgical hemorrhage probably resulted from a venous thrombosis: 1) no evidence of residual AVM; 2) delayed onset of the hemorrhage, inconsistent with the time course of a hemorrhage developing according to the breakthrough theory or with insufficient hemostasis with a high-pressure afterload; 3) good correlation between the location of the hemorrhage and the occlusion of the draining veins; and 4) multifocal hemorrhage affecting both the gray matter and the subcortical white matter. Postoperative hemorrhagic infarction caused by thrombosis in the draining veins is rare, but it should be considered as a distinct postoperative complication after removal of an AVM.

Site and Mechanism of Vascular Stenosis under Increased Intracranial Pressure — Intracranial Venous Pressure Regulation Mechanism

Although many authors have suggested vascular congestion of venous system under increased intracranial pressure as a cause of CBF reduction, the exact site and mechanism of compression has remained obscure. The results of our previous investigations in dogs are summarized in Fig. 1. Cortical venous pressure (CVP), bridging venous pressure (bridging VP), and lateral lacunar pressure (lat lacuna P) were constantly 4–18 mmHg higher than ICP, regardless of the level of ICP, while superior sagittal sinus pressure (SSSP) is quite stable at low levels (4–6 mmHg). Thus, pressure gradients between the cortical arterial pressure and the CVP, gradually decrease as ICP is elevated, while the pressure gradient between the CVP and the SSSP continuously increases as ICP is elevated. These evidences indicate that vascular stenosis is taking place in the lateral lacuna of superior sagittal sinus.

Clinical Significance of TCP Measurements Following Intracranial Surgery

The present study was intended to find out correlations between clinical manifestations and the level and course of ICP following major intracranial surgery.

Treatment of Unruptured Cerebral Aneurysms Associated with Intracranial Arteriovenous Malformations

In this paper, the authors report on 9 cases of unruptured cerebral aneurysms associated with intracranial arteriovenous malformations (AVMs), and discuss therapeutic problems of unruptured aneurysms. The following are our conclusions: 1) The rate of combinations of AVMs and aneurysms is not small . Therefore, precise preoperative neuroradiological examinations should be made to confirm the presence or absence of aneurysms in all patients with cerebral AVMs. 2) We were unable to conclude whether or not unruptured aneurysms associated with AVMs should be operated on. However, no decrease in size of aneurysms following excision of AVMs is one important indication for considering a radical operation for aneurysms. 3) The authors reported one case who suffered retrograde thrombosis of the feeding artery , and developed neurological deficits after radical operation for on unruptured aneurysm of the feeding artery. Timing of radical operation for aneurysms following the excision of AVMs must be carefully considered. When surgical treatment of an aneurysm is intended, special attention should be paid to cerebral circulation following excision of AVMs. When an angiographical finding of stagnant arterial flow of feeding arteries is observed, radical operation for aneurysms should be avoided.