Teresa Lin, Allan J. Fox and Charles G. Drake
✓ It is recognized that incomplet treatment of an aneurysm may result in recurrent hemorrhage with serious or fatal consequences. For this reason, patients treated at the authors' institution in whom a large portion of the aneurysm neck or sac remained after application of a clip or ligature have been subjected to reoperation. However, 1- to 2-mm residual necks seen in postoperative angiography have been thought to pose little risk. Some cases of aneurysms recurring from a narrow residual neck after clipping have been reported, and a few instances of recurrent aneurysm have been described after apparently complete occlusion of the neck (as observed angiographically or in the surgeon's judgment). In recent years, a surprising number of cases have been presented in which this seemingly unimportant remnant of the neck dilated over a long period to become a dangerous aneurysm. This finding stresses the importance of complete aneurysm occlusion and of postoperative angiography for the recognition of a residual aneurysm neck. This should be important not only in aneurysm clipping but also in the endovascular treatment of intracranial aneurysms with detachable balloons.
Jonathan E. Hodes, Allan J. Fox, David M. Pelz and Sydney J. Peerless
✓ Three cases of complex aneurysms are presented in which balloon embolization therapy was associated with subsequent aneurysmal rupture, causing subarachnoid hemorrhage in two cases and a carotid-cavernous fistula in one. Two of these patients were treated directly by balloon embolization following surgical exploration. The third patient developed the fistula during postembolization volume expansion and heparinization.
Report of three cases
Matthew F. Omojola, Allan J. Fox, Fernando V. Viñuela and Charles G. Drake
✓ This is a report of spontaneous regression of intracranial arteriovenous malformations (AVM's) in three female patients; two of these patients had complete angiographic disappearance of the AVM, including an instance of intimate association of the AVM with an astrocytoma. The AVM's in these two patients were unicompartmental medium- to large-sized lesions supplied by a single feeder and draining principally through one large vein; spontaneous thrombosis is suggested as a cause of the AVM regression. Partial regression in the third patient might have been partially due to embolism from a clot-filled aneurysm on the feeding vessel. The significance of such disappearance of AVM's in relation to persistence or otherwise of the neurological status of these patients is discussed.
Fernando V. Viñuela, Gerard M. Debrun, Allan J. Fox and Shinichi Kan
✓ The authors describe a system comprising a small latex balloon attached to a Teflon catheter. The balloon has a distal calibrated leak which is used for intravascular embolization with isobutyl-2-cyanoacrylate. The balloon is easily detached after embolization. The combination of manual control of the balloon-catheter system, plus the ability of the balloon to navigate intra-arterially with the blood flow, makes this system suitable for superselective angiography and embolization of lesions supplied by the external carotid artery (ECA). This system avoids intimal dissection and concomitant arterial vasospasm when trying to negotiate steep distal curves of the ECA branches. Experimental embolization of several branches of the ECA in the dog, and clinical examples of treatment of dural arteriovenous malformations in three patients are described.
Fernando Viñuela, Allan J. Fox, Shinichi Kan and Charles G. Drake
✓ A case is reported of a large spontaneous right posterior inferior cerebellar artery fistula in which the patient presented with a right cerebellopontine (CP) angle and right cerebellar syndrome. The patient was successfully treated by balloon occlusion at the fistula site. The location of the arteriovenous fistula, the mass effect of its enlarged draining veins on the cerebellum and CP angle structures, and the simple therapeutic endovascular occlusion with a detachable balloon make this case unique.
Review of 16 cases
Gyula Gács, Fernando Viñuela, Allan J. Fox and Charles G. Drake
✓ True congenital peripheral aneurysms of the cerebral arteries are rare and may constitute a special group. The authors report on 16 cases of peripheral aneurysms of the cerebellar arteries; six of them arising from vessels feeding arteriovenous malformations (AVM's). The possible causative role of increased blood flow versus developmental factors in the frequent occurrence in cases of AVM of this otherwise rare type of aneurysm is discussed. In five of the six cases with AVM's (one dural and five parenchymal), the aneurysm rather than the AVM proved to be the source of the hemorrhage. The occurrence of spasm was in inverse proportion to the distance of the aneurysm from the main arteries. The surgical result was good in 11 cases. One patient with associated AVM died, and four patients had residual symptoms.
Significance of angiographic morphology of the posterior communicating arteries
David M. Pelz, Fernando Viñuela, Allan J. Fox and Charles G. Drake
✓ The clinical and angiographic records were reviewed for 71 patients with giant aneurysms of the posterior circulation, who underwent therapeutic occlusion of the basilar artery or both vertebral arteries. This treatment is used when the aneurysm neck cannot be surgically clipped, and occlusion of the parent artery is performed to initiate thrombosis within the lumen. In these cases, collateral blood flow to the brain stem is supplied mainly by the posterior communicating arteries. Consequently, their angiographic morphology (patency, size, and number) is demonstrated as a preoperative indicator of whether the patient will be able to tolerate vertebrobasilar occlusion. Vertebral angiograms with carotid artery compression (the Allcock test) will often be needed to provide this information.
The data relating posterior communicating artery morphology to clinical outcome in 71 cases of attempted vertebrobasilar occlusion are presented. The use and accuracy of carotid artery compression studies are also discussed. It is essential for the radiologist to supply the neurosurgeon with this valuable information in every case of giant posterior circulation aneurysm.