Geometric changes from the symmetrical to the asymmetrical ACoA develop higher shear stress on the ACoA than critical values and the stagnation point at the ACoA junction. A combination of these hemodynamic factors is considered to play an important role in initiation of aneurysm.

Brain abscess is a serious complication of congenital cyanotic heart disease. We retrospectively evaluated the risk factors for brain abscess in 21 such patients treated between 1975 and 1990 in comparison with a control group. The mean arterial oxygen saturation, arterial partial pressure of O2, arterial blood oxygen content, and base excess in patients with brain abscess were significantly lower than in the control patients. The mean arterial partial pressure of CO2, pH, hematocrit, hemoglobin, and red blood cell content in patients with brain abscess were not significantly different. Patients with congenital cyanotic heart disease may develop minute encephalomalacia due to severe hypoxemia and increased blood viscosity resulting from compensatory polycythemia. The increased blood viscosity and reduced blood flow in the microcirculation may induce cerebral thrombosis or exaggerate minute encephalomalacia during dehydration or cardiac dysfunction, and shunted blood containing infectious organisms at such sites may be followed by focal cerebritis.

ObjectiveWe sought to determine the patency of normal arterial branches from the covered segments of an artery after stenting.BackgroundMost intracranial aneurysms occur at arterial branching points (bifurcations, side-branches, or perforators). The post-stenting patency of normal arterial branches from the covered segments of the artery is important. We have previously developed a hybrid stent with micropores to prevent early parent artery occlusion by more early endothelialization, and mid- to long-term parent artery stenosis by control of intimal hyperplasia after aneurysm occlusion.MethodsWe created aneurysms in 10 rabbits by distal ligation and intraluminal incubation of elastase within an endovascularly trapped proximal segment of the common carotid artery. All animals were treated with hybrid stents having micropores. Four animals were observed for one month and three each for three and 12 months. The patency of the side-branches of the subclavian artery was evaluated angiographically and in some cases, histologically.ResultsAneurysms were completely occluded at all time points other than 12 months. The subclavian artery and brachiocephalic artery were patent, without significant stenosis. All the side-branches of the subclavian artery detected on the preoperative angiogram remained patent at the final assessment.ConclusionThe use of hybrid stents for aneurysm repair and side-branch patency seems to be effective, as per the long-term results obtained in an animal model.

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The superficial temporal artery to middle cerebral artery (STA-MCA) bypass is an effective surgical option to treat stenosis of the intra-or extra-cranial arteries. However, anastomosis of narrow arteries is a technically difficult procedure. Indeed, several complications including a damaged vessel during surgery have been reported. Here, we describe a successful arterial anastomosis during the STA-MCA bypass surgery. This approach comprised three steps. First, the cut end of the STA is prepared so that a neurosurgeon can easily keep the STA lumen open during anastomosis. Second, a sterile gelatin sponge is used to prevent flooding of spinal fluid. Third, sequential order of suturing in anastomosis of the STA and MCA is crucial. Combination of these tips provides an easy, fast, and solid approach, resulting in a secure anastomosis and at least one year of patency in 19 out of 20 cases.

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