Aneurysms of the posterior cerebral artery: report of ten cases

Ten cases of posterior cerebral artery (PCA) aneurysm are presented. There were 13 aneurysms in the 10 patients: 6 saccular, 5 fusiform, 1 broad-based, and 1 giant fusiform serpentine aneurysm. Eight patients underwent operation: clipping for 2 saccular aneurysms, trapping for 1 saccular and 3 fusiform aneurysms, and coating for 2 fusiform or broad-based aneurysms. Microsurgical cerebral revascularization techniques were attempted in 2 cases: after a fusiform aneurysm had been excised, end-to-end anastomosis of the residual two ends of the PCA was performed and, after a giant serpentine aneurysm had been trapped, the superficial temporal artery was anastomosed transcortically to the distal PCA. Two patients died before operation because of rebleeding and vasospasm. Postoperative neurological deficits include contralateral hemiparesis, homonymous hemianopsia, hemihypesthesia, and ipsilateral 3rd nerve palsy. Our results suggest that, despite the good collateral circulation of the PCA, some ischemic events may occur after trapping procedures and that cerebral revascularization techniques may have some benefit in the treatment of unclippable aneurysms in this region.     

A giant dissecting aneurysm mimicking serpentine aneurysm angiographically

Intracranial dissecting and giant serpentine aneurysms are rare vascular anomalies. Their precise cause has not yet been completely clarified, and the radiological appearance of such lesions can be different in each case according to the effect of hemodynamic stress on a pathologic vessel wall. For berry aneurysms, available evidence overwhelmingly favors their causation by hemodynamically induced degenerative vascular disease and there is an obvious need to determine the hemodynamic parameters most likely to induce the precursor atrophic lesions. In this study, a case of a giant dissecting aneurysm angiographically mimicking serpentine aneurysm of the right ophthalmic artery is reported and the relevant literature is reviewed to investigate the pathological characteristics and pathogenesis of this lesion. In the present case, radiological investigation of the lesion suggested a serpentine aneurysm, but the diagnosis was corrected to dissecting aneurysm subsequent to the pathological examination of the resected aneurysm. A giant dissecting aneurysm angiographically mimicking serpentine aneurysm and developing as the result of a circumferential dissection located between the internal elastic lamina and media is of particular interest when the etiology of these aneurysms is considered. To our knowledge this is the first report on intracranial dissecting aneurysm mimicking serpentine aneurysm angiographically. Our case illustrates the importance of careful serial section studies for a better understanding of the vascular pathology underlying the processes involved in intracranial serpentine aneurysms. We conclude that serpentine, dissecting and berry aneurysms may all arise by way of similar pathophysiological mechanisms.     

Giant serpentine intracranial aneurysm

Giant serpentine aneurysms are considered a distinct sub-group of giant aneurysms because of their characteristic angiographic appearance and clinical behavior. A case of this unusual vascular abnormality showing progressive enlargement documented by computed tomography and cerebral angiography is presented, along with a review of the literature. Etiology, pertinent radiological findings, and a probable mechanism of serpentine channel formation are discussed.     

Long-term follow-up of giant serpentine MCA aneurysm treated with EC–IC bypass and proximal occlusion

Summary Giant serpentine aneurysms are a rare but important subset of giant aneurysms, with unique management considerations. We present long-term follow-up clinical and imaging features of a giant serpentine middle cerebral artery lesion treated with extracranial–intracranial bypass and proximal occlusion more than a decade earlier. Calcification of the obliterated aneurysm sac and durability of this management strategy are demonstrated.     

Distal intracranial arterial aneurysms. Apropos of a case of giant aneurysm of the right angular gyrus artery

A 57 year old man presented with a giant, fusiform, partially thrombosed aneurysm, located distally to the right angular gyrus artery, and revealed by a subarachno?d hemorrhage. There was no history of head trauma, endocarditis or systemic infection, and physical examination was normal. The treatment consisted in simple trapping of the aneurysm, responsible for a transient ischemic parietal syndrome. After a short review of the pathogenesis of peripheral aneurysm of the C.N.S., and previously reported cases of distally located aneurysms of the middle cerebral artery, only one similar case was found concerning a posterior temporal artery aneurysm involving to a giant serpentine aneurysm. The case presented is believed to be a segmentary form of cerebral arterial dolicho ectasia; relations between arterial ectasia or fusiform aneurysms and serpentine aneurysms are discussed.     

Cerebral giant serpentine aneurysm: case report and review of the literature

We present a case of cerebral giant serpentine aneurysm (GSA) and propose a definition of GSA. Our literature review disclosed only 16 cases, including our own, that fit our criteria. GSAs belong to the subgroup of giant aneurysms, but are distinct from giant saccular and fusiform aneurysms. We discuss their specific characteristics.     

Coil embolization of giant serpentine aneurysms: report of two cases arising from the posterior cerebral artery

The authors describe the presentation, investigation and successful treatment of two giant serpentine aneurysms with Guglielmi detachable coils. Both aneurysms selectively involved the P2 segment of the posterior cerebral artery. The authors describe an endovascular approach to these challenging lesions as an alternative/adjunct to conventional surgery.     

Giant serpentine aneurysms: a separate entity

Giant intracranial aneurysms containing a tortuous vascular channel appear, to some extent, different from other giant aneurysms. Their particular features are outlined in the present report which concerns a case of a small fusiform aneurysm of the posterior temporal branch of the middle cerebral artery evolving over five years into a giant serpentine aneurysm. Successful and complete removal of this lesion was achieved.     

Spontaneous fusiform middle cerebral artery aneurysms: characteristics and a proposed mechanism of formation

OBJECT: The goal of this study was to identify the origins of spontaneous fusiform middle cerebral artery (MCA) aneurysms. METHODS: One hundred two cases of spontaneous fusiform MCA aneurysms were reviewed, including 40 from the authors' institutions and 62 identified from the literature. The mean age at symptom onset was 38 years, and the male/female ratio was 1.4:1. At presentation, the MCA lumen was stenosed or occluded in 12 patients, focally dilated in 57, and appeared "serpentine" in 33. Most lesions originated from the M1 or M2 segments, and most (80%) presented with nonhemorrhagic symptoms or were discovered incidentally. The presenting clinical features correlated with morphological findings in the aneurysms, which could be observed to progress from a small focal dilation or vessel narrowing to a serpentine channel. Hemorrhage was the most common presentation in small lesions; the incidence of bleeding progressively diminished with larger lesions. Patients with stenoses or occluded vessels most often presented with ischemic symptoms, and occasionally with hemorrhage. Giant focal dilations or serpentine aneurysms were rarely associated with acute bleeding; clinical presentation was most often prompted by mass effect or thromboembolic stroke. CONCLUSIONS: Analysis of results after various treatments indicates that for symptomatic lesions, therapies that reverse intraaneurysmal blood flow and augment distal cerebral perfusion are associated with better outcomes than other strategies, including conservative management. Based on the spectrum of clinical, pathological, neuroimaging, and intraoperative findings, dissection is proposed as the underlying cause of these lesions.     

Endovascular trapping of giant serpentine aneurysms by using Guglielmi detachable coils: successful reduction of mass effect. Report of two cases

Giant serpentine aneurysms (GSAs) are defined as partially thrombosed giant aneurysms with persistent serpentine vascular channels. Surgical management of these rare lesions is difficult because of their large size, complex structure, and unique hemodynamics. The authors report two cases of patients harboring GSAs with mass effect, which were managed effectively with endovascular treatment. The first patient was a 48-year-old man who presented with left homonymous hemianopsia caused by a GSA involving the terminal portion of the right internal carotid artery. The second patient, a 10-year-old boy, presented with tetraparesis from compression of the cervicomedullary junction by a GSA of the right vertebral artery. In each case, after confirming collateral flow by temporarily occluding the proximal artery, the aneurysm was trapped by placement of Guglielmi detachable coils at the sites at which the serpentine channels entered and exited the aneurysm. The midportion of each channel was isolated completely without packing, to maximize resorption of the devascularized mass. Mass effect and clinical symptoms rapidly improved in both cases, with no associated morbidity. We recommend endovascular trapping as a safe and effective therapeutic option for GSAs.     

Giant serpentine aneurysm in a long-term hemodialysis patient

A long-term hemodialysis patient with a giant intracranial vascular channel, which has been called a giant serpentine aneurysm, is presented. A 50-year-old man with an eight-year history of hemodialysis treatment was admitted because of headache, nausea and double vision. Computed tomographic scans and nuclear magnetic resonance revealed intracranial abnormal shadow. The left vertebral arteriography showed that the distal portion of the left vertebral artery was dilated to 17 mm in diameter. The basilar artery showed a large tortuous vascular channel and globular aneurysms over 25 mm in diameter. This giant serpentine aneurysm is a rather rare disease. To our knowledge, it has not been reported as a complication in a hemodialysis patient, although fourteen cases have been reported in the literature. In our case, several conditions such as long-term hypertension, hyperlipidemia, hypercalcemia, atherosclerosis and abnormal blood flow due to arteriovenous fistula for hemodialysis treatment might be considered to play a role in the formation of the giant serpentine aneurysms.     

The pretzel sign: angiographic pattern of tortuous intra-aneurysmal blood flow in a giant serpentine aneurysm

Giant serpentine aneurysms (GSAs) form a specific subgroup of giant cerebral aneurysms that have pathognomonic angiographic features. We report the angiographic findings of a GSA demonstrating a striking convoluted dynamic flow pattern, which we have called the 'pretzel sign'. The aneurysm was successfully treated by permanent occlusion of the parent vessel using a detachable balloon. GSAs should be identified prior to treatment in view of their particular management requirements.     

颅内后循环动脉瘤的血管内介入治疗

目的总结颅内后循环动脉瘤的特点,探讨其血管内介入治疗的临床疗效。方法回顾性分析40例行血管内介入治疗的颅内后循环动脉瘤患者的临床和影像学资料、介入治疗过程,观察期效果及术后随访结果。结果 40例患者共发现42个后循环动脉瘤,均完成血管内介入治疗,其中8个行单纯弹簧圈栓塞,28个行支架辅助栓塞,1个行Onyx胶栓塞,5个动脉瘤及载瘤动脉同时闭塞。术后即刻DSA造影显示动脉瘤完全栓塞30个,近全栓塞6个,部分栓塞6个。术后6个月随访DSA造影显示动脉瘤完全栓塞36个,近全栓塞4个,部分栓塞1个。患者出院时行改良Rankin量表(mRS)评分,0分35例,1分3例,2分1例,1例死亡为6分;出院后3~6个月随访mRS评分0分38例,1分1例,无动脉瘤复发及新发神经功能障碍病例。结论颅内后循环动脉瘤具有特殊的临床与影像学表现,且复杂动脉瘤较为常见,对于颅内后循环动脉瘤,血管内介入治疗是一种安全有效的治疗方法。     

Predicting the risk of rupture of intracranial aneurysms based on anatomical location

Summary The location of intracranial aneurysms may be a significant independent risk factor for predicting aneurysm rupture. A recent report found high bleed rates from posterior communicating artery aneurysms which had not previously been noted. On this distinction hangs the decision whether to treat a large number of unruptured aneurysms.In the recent publication by the International Study of Unruptured Intracranial Aneurysms (ISUIA), two bleeds from small incidental posterior communicating artery aneurysms were noted and these aneurysms were reported to have a similar risk to aneurysms of the posterior circulation and as a result were grouped with them. This was a post hoc analysis so the justification for this assertion is tenuous. The hypothesis that posterior communicating aneurysms are of similar risk to posterior circulation aneurysms requires further testing on other data before it can be confidently accepted.A review of the literature was undertaken to define relative risks of rupture for different anatomical locations and to test the above hypothesis. Eleven papers were found to contain sufficient data to calculate rupture rates for anatomical sub groups. Studies contained a total of 30,204 patient years of follow up.Results showed the internal carotid artery to be the commonest site for unruptured aneurysms (38%). Aneurysms located in the posterior circulation had an overall annual bleed rate of 1.8%. This compares with 0.49% for the anterior circulation. The bleed rate from aneurysms of the posterior communicating artery (0.46% per year) was similar to that of the rest of the anterior circulation.The ISUIA post hoc hypothesis fails when tested on these data and the ISUIA data should be re-analysed with posterior communicating artery aneurysms grouped with the anterior circulation where they more traditionally belong.     

Giant aneurysms of the vertebral artery. Report of five cases

The authors report five cases of surgically treated giant vertebral artery aneurysm. Two giant serpentine aneurysms were managed with aneurysmectomy, a giant semifusiform aneurysm with trapping and partial aneurysmectomy, and the other two saccular giant aneurysms with clipping. Surgical results were satisfactory in all cases. In particular, the two patients who underwent complete aneurysmectomy showed remarkable improvement after the second procedure of a two-stage operation that consisted of initial proximal occlusion and secondary evacuation of clots in the aneurysm when advanced thrombosis was identified. Aneurysmectomy in a two-stage operation was the best treatment for these partially thrombosed giant aneurysms which completely concealed the distal artery under a tight thinned medulla.     

Management of giant serpentine aneurysms of the middle cerebral artery — Review of literature and report of a case successfully treated by STA-MCA anastomosis only

Summary Thirty-eight cases of giant serpentine aneurysms (GSA), including 17 GSA of the middle cerebral artery (MCA), were reviewed in the literature. The treatment possibilities of GSA of the MCA are discussed together with our own case who was a 39-year-old male with a GSA of the right MCA and was treated only by STA-MCA anastomosis. The pathogenetic mechanism of progressive enlargement of the aneurysm is also discussed.     

Distal anterior cerebral artery aneurysms: report of 26 cases

Distal anterior cerebral artery (ACA) aneurysms are rare, and constitute approximately 1.5% to 9% of all intracranial aneurysms. They show some unique features compared with other aneurysms in the cerebral circulation and are frequently treated with a different technique. Twenty-six of 364 patients with cerebral aneurysms treated at our department between 1996 and 2004 had distal ACA aneurysms (7.1%). Twenty-three of the 26 patients were treated through an anterior interhemispheric approach and two with a pterional approach. All saccular aneurysms were successfully clipped except one which was embolized after the surgery. The only fusiform aneurysm spontaneously thrombosed and resolved with parent artery occlusion. Two of the 26 patients had multiple aneurysms. The surgical mortality was 8%. Distal ACA aneurysms have higher mortality and morbidity than other anterior circulation aneurysms. They should be aggressively treated even if very small because of the tendency to rupture. Endovascular treatment is an alternative in the management of these aneurysms. The most important factors affecting the outcome are grade on admission and the neurosurgeon's experience.     

Saphenous vein bypass grafts for giant aneurysms and intracranial occlusive disease

The authors report their experience with the use of saphenous vein bypass grafts for treating advanced occlusive disease in the posterior circulation (77 patients, all of whom had failed medical management and showed severe ischemic symptoms), deteriorating patients with giant aneurysms of the posterior circulation (nine patients), progressive ischemia in the anterior circulation (26 patients, none of whom had a normal examination), and giant aneurysms in the anterior circulation (20 patients, all of whom presented with mass effect or subarachnoid hemorrhage). Graft patency in the first 65 cases treated was 74%. However, after significant technical changes of vein-graft preparation and construction of the proximal anastomosis, patency in the following 67 cases was 94%. Excellent or good results (including relief of deficits existing prior to surgery) were achieved in 71% of patients with advanced occlusive disease in the posterior circulation, 44% of those with giant aneurysms of the posterior circulation, 58% of those with ischemia of the anterior circulation, and 80% of those with giant aneurysms of the anterior circulation. Mean graft blood flow at surgery in the series was 100 ml/min for posterior circulation grafts and 110 ml/min for anterior circulation grafts. Experience to date indicates that this is a useful operation, and is particularly applicable to patients who are neurologically unstable from advanced intracranial occlusive disease in the posterior circulation or with giant aneurysms in the anterior circulation. The risk of hyperfusion breakthrough with intracerebral hematoma restricts the technique in patients with progressing ischemic symptoms in the anterior circulation, and the intolerance of patients with fusiform aneurysms in the posterior circulation to the iatrogenic vertebrobasilar occlusion limits the applicability of this approach to otherwise inoperable lesions in that system.     

Dissecting intracranial aneurysms presenting as subarachnoid haemorrhage: report of two cases and review of literature

Subarachnoid haemorrhage due to intracranial non-traumatic dissecting aneurysms is rare. Most of the published reports refer to dissecting aneurysms in the vertebrobasilar territory. Anterior circulation dissecting aneurysms are rare and their pathogenesis, clinical features, angiographic findings and management are a matter of debate. Management of patients with intracranial arterial dissection is unclear. Unlike the well-established proximal occlusion and trapping approaches to vertebral artery dissections, choices of interventions for anterior circulation and basilar dissecting aneurysms are limited, and most reports have been limited to wrapping techniques for arterial wall reinforcement. The role of anticoagulation therapy in the presence of subarachnoid haemorrhage is also a matter of debate. As no clear-cut guidelines are available, treatment should be tailored to the individual patient. We describe two cases of intracranial dissecting aneurysms, which presented as subarachnoid haemorrhage (SAH) and discuss the management issues.     

Surgical treatment of multiple aneurysms and of incidentally-discovered unruptured aneurysms

Review of a series of 460 patients with spontaneous intracranial hemorrhage showed that 241 had demonstrable aneurysms and 38 had multiple aneurysms. The importance of demonstrating the entire circulation following ligation of one aneurysm is emphasized. Treatment of the 38 patients with multiple aneurysms is described. Ligation of unruptured aneurysms that are incidentally discovered is advocated in patients who are Grade 1 on the Botterell scale and who are well informed as to the risks.