Rupture of Intradural Giant Aneurysms: The Mode of Treatment, Anatomical, and Mechanical Factors

The off-label uses of pipeline embolization device for complex cerebral aneurysms: Mid-term follow-up in a single center

ObjectiveTo describe the off-label uses of pipeline embolization device for a variety of types of aneurysms including ruptured aneurysms, posterior circulation aneurysms, small aneurysms, distal aneurysms, and recurrent aneurysms.MethodsClinical and angiographic data of patients who underwent pipeline embolization device treatment on off-label use at our center were retrospectively reviewed. For categorical variables, Fisher's exact test was used, and a two-sample Wilcoxon rank-sum test was used for patients' age to analyze the correlation with outcomes.ResultsIn this study, 121 aneurysms in 107 patients received off-label pipeline embolization device treatments. The overall rate of complete aneurysm occlusion was 77.8% (28/36 in 35 patients) for posterior circulation aneurysms and 95.3% (81/85 in 72 patients) for anterior circulation aneurysms. The posterior circulation aneurysms have a lower rate of aneurysm occlusion (p = 0.0372). The small aneurysms have a higher rate of aneurysm occlusion (p = 0.0104). The patient's sex, age, and aneurismal size were associated with ischemic stroke complications (p = 0.0397, 0.0166, and 0.0178). In posterior circulation aneurysm patients, only two basilar apex aneurysms underwent pipeline embolization device treatment, both of whom died of thrombotic complications. There was no difference in mortality between posterior circulation aneurysm patients (8.6%, 3/35) and anterior circulation aneurysm patients (1.4%, 1/72) (p = 0.1015). Patients of older age have a higher risk of death rate (p = 0.0053).ConclusionsThe off-label use of pipeline embolization device is often performed in clinical practice and can achieve efficacy in complex aneurysms. The off-label use of pipeline embolization device was found to carry an increased rate of mortality in older patients. Excluding basilar apex aneurysms, the pipeline embolization device is as safe as anterior circulation aneurysms in the treatment of posterior circulation aneurysms elsewhere.

Computational fluid dynamics; a new diagnostic tool in giant intracerebral aneurysm treatment

Giant intracerebral aneurysms (GIA) comprise up to 5 % of all intracranial aneurysms. The indirect surgical strategy, which leaves the GIA untouched but reverses the blood flow by performing a bypass in combination with proximal parent artery occlusion is a useful method to achieve spontaneous aneurysm occlusion. The goal of this study was to assess the utility of computational fluid dynamics (CFD) in preoperative GIA treatment planning. We hypothesise that CFD simulations will predict treatment results. A fluid-structure interaction (FSI) CFD investigation was performed for the entire arterial brain circulation. The analyses were performed in three patient-specific CT angiogram models. The first served as the reference geometry with a C6 internal carotid artery (ICA) GIA, the second a proximal parent artery occlusion (PAO) and virtual bypass to the frontal M2 branch of the middle cerebral artery (MCA), and the third a proximal PAO in combination with a temporal M2 branch bypass. The volume of "old blood", flow residence time (FRT), dynamic viscosity and haemodynamic changes were also analysed. The "old blood" within the aneurysm in the bypass models reached 41 % after 20 cardiac cycles while in the reference model it was fully washed out. In Bypass 2 "old blood" was also observed in the main trunk of the MCA after 20 cardiac cycles. Extrapolation of the results yielded a duration of 4 years required to replace the "old blood" inside the aneurysm after bypass revascularization. In both bypass models a 7-fold increase in mean blood viscosity in the aneurysm region was noted. Bypass revascularization combined with proximal PAO favours thrombosis. Areas prone to thrombus formation, and subsequently the treatment outcomes, were accurately identified in the preoperative model. Virtual surgical operations can give a remarkable insight into haemodynamics that could support operative decision-making.

Giant Aneurysms: Not So Giant in Behavior

BACKGROUND

Giant intracranial aneurysms (GIAs) are very complex in their behavior and treatment procedure. There are various modalities of treatment. The annual rupture rate of GIA (6%) is higher than that of small aneurysms (1-3%). Neurosurgeons handle these aneurysms during operations.

OBJECTIVE

We tried to analyze the intraoperative rupture rate (IRR) of GIA in relation to small aneurysms. IRR is concerned with the rupture of the aneurysms during operative handling.

MATERIALS AND METHODS

For conducting the study, we compared the IRR of 7 GIAs and 45 small aneurysms during a span of 10 years. All the operations were performed by the same team and the same principal surgeon. IRR was compared by statistical analysis.

RESULT

Z-test was done to compare the two rates: Z = 0.68 and P = 0.49. According to our study, the IRR of GIA is not statistically different from small aneurysms. The IRR of GIA is not higher because of three factors which we have analyzed: 1) layers of intraaneurysmal thrombus, 2) fibrin deposition on the aneurysm wall, and 3) blocked neck of the aneurysm by thrombus.

CONCLUSION

The IRR of GIA is not different from small aneurysms.