Study and Therapeutic Progress on Intracranial Serpentine Aneurysms

Giant serpentine aneurysm: Neuroradiological and neurosurgical management in a left-handed patient

Giant serpentine aneurysms are rare huge and partially thrombosed aneurysms, with an eccentric tortuous intra-aneurysmal vascular channel. Surgical treatment is often necessary due to the great mass effect. We describe a case of a left-handed woman with a giant serpentine aneurysm of the left middle cerebral artery whose management was complex. The challenge was to exclude the aneurysm from circulation, reduce the mass effect, and, mostly, preserve the language function. Since the patient was left-handed the language dominance needed to be assessed; functional MRI (fMRI) and Wada test (WT) showed a right dominance. Surgical treatment was performed, as a complication, the patient developed left fronto-basal ischemia with a slight paresis of the right hand but without any language deficit. Our case shows the importance of a multidisciplinary team in patient management, with a pivotal role of neuroradiological functional tests in presurgical planning.

Flow diversion treatment for giant intracranial serpentine aneurysms

Background

Giant serpentine aneurysms (GSAs) are among the most complex and challenging type of intracranial aneurysms. Surgical clipping, bypass, or endovascular parent artery occlusion has been the main treatment of GSAs in the past. However, studies on flow diversion (FD) are limited. Therefore, we reported our experience with patients with GSAs treated with FD.

Methods

Patients with GSAs treated with FD from 2012 to 2020 in our single center were retrospectively reviewed. Angiographic outcomes were graded according to the O’Kelly–Marotta scale as complete occlusion (D), trace filling (C), entry remnant (B), or aneurysm filling (A). Clinical outcomes were assessed using the modified Rankin scale (mRS) score. We also collected the patients’ treatment details and perioperative complications.

Results

Thirteen patients with 14 aneurysms were included, including three in the anterior circulation and 11 in the posterior circulation. Grades B–D were found in 72.7% (8/11) of the GSAs. Good prognosis (mRS score, 0–2) was found in 66.7% (8/12) and 50.0% (6/12) of the patients at the 6-month and latest follow-up, respectively. Parent artery occlusion was found in three cases of GSAs. Five postoperative complications were observed, including two minor complications and three major complications.

Conclusion

Although reconstructive treatment with FD could be considered as one of the treatment strategies for patients with both anterior and posterior circulation GSAs, however, the risk of complications and parent artery occlusion should be considered.

Giant Aneurysm Management

The treatment of giant aneurysms has always been a challenge in the field of neurovascular disease. Giant aneurysms are larger in size and are associated with thrombosis development and the calcification of the aneurysmal wall and neck, which often interfere with direct clipping. Most giant aneurysms have a wide neck with an incomplete thrombus, making complete embolization almost impossible. Giant aneurysms of different sites have entirely different hemodynamic characteristics. Moreover, aneurysms at the same site may exhibit very different hemodynamics among different individuals. Therefore, careful assessment of each case is required before and during treatment to develop and carry out an individualized treatment plan.

Endovascular Treatment of Posterior Cerebral Artery Trunk Aneurysm: The Status Quo and Dilemma

The posterior cerebral artery (PCA) is an important artery that can be divided into four segments (P1-4): segments P1-2 are proximal segments, and segments P3-4 are distal segments. Various aneurysms can occur along the PCA trunk. True saccular aneurysms are rare, and most PCA trunk aneurysms are dissecting. Sometimes, the PCA trunk can give rise to flow-related aneurysms in association with high-flow arteriovenous shunt diseases or moyamoya disease and internal carotid artery occlusion. Some PCA trunk aneurysms require treatment, especially ruptured or large/giant aneurysms. Recently, endovascular treatment (EVT) has become the mainstream treatment for PCA trunk aneurysms, and it mainly involves reconstructive or deconstructive techniques. Traditional EVT includes selective coiling with/without stent or balloon assistance and parent artery occlusion (PAO). For proximal aneurysms, the PCA should be preserved. For distal aneurysms, PAO can be performed. However, during EVT, preservation of the PCA must naturally be the prime objective. Recently, flow-diverting stents have been used and are a revolutionary treatment for unruptured dissecting aneurysms of the PCA trunk. Despite the associated complications, EVT remains an effective method for treating PCA trunk aneurysms and can result in a good prognosis.

Intracranial Fusiform and Circumferential Aneurysms of the Main Trunk: Therapeutic Dilemmas and Prospects

Intracranial fusiform and circumferential aneurysms (IFCAs), especially those located on the main trunk, are uncommon and difficult to manage. Currently, literature focused on IFCAs on the main trunk of cerebral arteries is lacking. The treatment of IFCAs is still under debate. Therefore, in this review, we further explore the treatment of this complicated entity. In addition, we also present some interesting cases. Based on the literature review and our experience, we found that IFCAs are often located in the vertebrobasilar system and that ruptured or large symptomatic IFCAs are associated with increased mortality and higher rebleeding rates. The treatment strategies for IFCAs can be classified as deconstructive and reconstructive methods via open surgery and/or endovascular treatment (EVT). Currently, EVT is a popular method and the main therapeutic choice. In particular, flow diversion has revolutionized the treatment of IFCAs. Parent artery occlusion (PAO) with or without revascularization may still be considered a suitable choice. Complex IFCAs that cannot be resolved by EVT can also be treated via open surgery with or without extracranial–intracranial bypass. Targeted embolization for the weak points of IFCAs is a temporary or palliative choice that is rarely used. In summary, despite complications, both surgical treatment and EVT are effective options for appropriately selected cases. Due to the development of endovascular implants, EVT will have better prospects in the future.

Progressive Pure Arterial Malformations of the Anterior Cerebral Artery

BACKGROUND

Pure arterial malformations (PAMs) are rare intracranial vascular anomalies. As recently reported, PAMs have a benign natural history and can be treated conservatively. However, their etiology, natural history, and treatment have not yet been fully elucidated.

METHODS

We present a rare case of the progression of a PAM involving the anterior cerebral artery. Magnetic resonance imaging showed a mass located in the suprasellar region associated with obstructive hydrocephalus. Digital subtraction angiography showed evolution of the arterial anomaly with progression compared with the studies 3 years earlier. Surgical trapping of the parent artery with electrophysiological monitoring was performed. Combined with previous data, the clinical features and therapeutic strategies for this unusual entity are discussed.

RESULTS

The patient recovered uneventfully after surgery. Postoperative digital subtraction angiography confirmed complete obliteration of the lesion. Axial computed tomography also showed shrinkage of the aneurysm, with improvement of the hydrocephalus. Our review of the reported data showed only 4 patients with a definite or probable PAM who had undergone surgery. To the best of our knowledge, the present case represents the first report of changes in the vascular architecture of a PAM during the follow-up period.

CONCLUSION

Whether the aneurysmal component of PAMs merits invasive treatment has remained controversial. The findings from our case raises the possibility of evolution for some patients with PAMs and stresses the importance of scheduled follow-up noninvasive imaging studies to rule out progression of these nosological entities, especially PAMs with an "aneurysm-like" component.

Intracranial Serpentine Aneurysms: Spontaneous Changes of Angiographic Filling Pattern

BACKGROUND AND PURPOSE

Serpentine aneurysms are partially thrombosed aneurysms with an eccentrically located tortuous intra-aneurysmal vascular channel. The large size, distinctive neck anatomy, and supply of the brain parenchyma by the outflow tract pose technical challenges in treatment. The aim of this study was to discuss the endovascular treatment results and illustrate the dynamic nature of serpentine aneurysms. Spontaneous transformation of saccular and fusiform aneurysms into serpentine morphology, along with a case of serpentine-into-fusiform aneurysm transformation during follow-up, is presented.

MATERIALS AND METHODS

A retrospective analysis from 3 institutions revealed 15 patients with serpentine aneurysms who underwent diagnostic evaluation and endovascular treatment. Nine of the 15 patients underwent endovascular occlusion of the parent vessel with detachable balloon or coils. Six of the 15 patients underwent aneurysm and parent artery occlusion with coiling.

RESULTS

In 11 patients, improvement or resolution of symptoms was achieved by an endovascular approach without any treatment-related morbidity. Morbidity related to treatment in the immediate postoperative period was seen in 3 patients, with resolution of the deficits at long-term follow-up in 2 patients and persistence of a mild deficit in 1 patient. Endovascular treatment failed to achieve resolution of symptoms in a case with a basilar tip aneurysm treated by aneurysm coiling.

CONCLUSIONS

Serpentine aneurysms are dynamic structures with spontaneous transformation possible from a saccular or fusiform shape into a serpentine configuration. An endovascular approach by parent vessel occlusion or intra-aneurysmal occlusion is a successful treatment technique for serpentine aneurysms.