Full Description
The first aneurysms explored by such pioneers of neurosurgery as Cushing and Dandy were the giant intracranial aneurysms. These giant aneurysms present many therapeutic difficulties and, because of their unique anatomical features and size, may present in a multitude of ways. With the advent of specialized imaging techniques such as computed tomography (CT), mag- netic resonance imaging (MRI) and selective angiography, preoperative diag- nosis today is most often accomplished without difficulty. However, com- pletely thrombosed giant aneurysms may mimic other lesions with mass effect (such as basilar meningiomas, chordomas or chondromas) and their true anatomical shapes and relations to other cranial structures can only be ascer- tained by direct operative inspection. Due to their morphological features (thrombosed, nonthrombosed, par- tially thrombosed, fusiform), anatomical variations and difficult locations, giant aneurysms present new challenges for the modern neurosurgeon.
Al- though microsurgical techniques have rendered direct surgical treatment of giant intracranial aneurysms safer, elimination of the aneurysm without dis- turbing the hemodynamics continues to be problematic. Some of these lesions have relatively small necks and can therefore be clipped fairly easily. Others have large necks, are fusiform, or contain perforators; how best to treat these lesions is a question still unresolved by presentday neurosurgery.
Contents
Anatomical Definition.- Mechanisms of Formation: Pathologic Features.- Macroscopic Findings.- Microscopic and Ultrastructural Findings.- Natural History of Giant Intracranial Aneurysms.- Mechanisms of Formation: Hemodynamic Features.- Review of the Literature.- Model Experiments.- Clinical Study.- Incidence and Distribution.- Topographic Types.- Giant Intracranial Aneurysms in Childhood.- Neuroradiological Features.- Plain Skull Radiographs.- Angiography.- Computed Tomography.- Magnetic Resonance Imaging.- Radionuclide Brain Scanning.- Direct Surgical Treatment by Neck Occlusion.- General Technical Considerations.- Direct Surgical Approaches According to Topographic Type.- Direct Surgical Treatment by Wrapping and Intravascular Thrombosis.- Wrapping.- Intravascular Thrombosis.- Extracorporeal Circulation.- Surgical Occlusion of the Carotid Axis (Cervical Common Carotid Artery and Cervical Internal Carotid Artery).- Effects of Carotid Occlusion.- Carotid Artery Occlusion in Giant Aneurysms.- Surgical Occlusion of the Vertebrobasilar Axis (Vertebral Artery and Basilar Trunk).- Hemodynamic Effects of Occlusion in the Vertebrobasilar System.- Results in the Treatment of Giant Aneurysms.- Intracranial Occlusion of the Parent Artery.- Proximal Occlusion.- Trapping.- Tolerance of Occlusion.- Implantable Vascular Occluder.- Extra-intracranial Bypass.- Methods.- Patency.- Applications in Giant Aneurysms.- Tests for the Tolerance of Therapeutic Occlusion.- Methods.- Selection of Patients.- Management by the Intravascular Approach.- Background.- Materials Used.- Methods.- Clinical Experience and Therapeutic Indications.- General Conclusions.
