The endovascular treatment of cerebral vasospasm was reviewed and recent concepts for this treatment were discussed. Percutaneous transluminal angioplasty (PTA) for vasospasm and the intra-arterial infusion of papaverine or fasudil hydrochloride comprise the endovascular treatment for cerebral vasospasm. Vasospasms of a proximal vessel are best suited for PTA with its lasting effect and vasospasms of a peripheral vessel are best suited for drug infusion with its less invasive nature. Ruptured aneurysms at the cerebral vasospasm onset phase from ischemic symptoms or re-rupture are also good candidates for endovascular treatment because simultaneous treatment is possible using the endovascular technique. The most important factor to the success of endovascular treatment of cerebral vasospasm is the timing of the treatment and we should catch this timing by carefully monitoring clinical signs and/or through transcranial Doppler sonography, cerebral blood flow studies.

View full abstract

Recently, the number of patients with atherosclerotic vertebrobasilar occlusive disease has increased. Various surgical treatments such as vertebral endarterectomy, vertebral to carotid transposition, vertebral to subclavian transposition or vertebral to carotid bypass using graft have been reported for extracranial vertebral artery occlusive disease. However, which technique should be applied to each pathological condition has not been sufficiently studied. Based on our experiences, vertebral to subclavian artery transposition is the best vascular reconstruction for cases of atherosclerotic stenosis at the origin of the vertebral artery when severe atherosclerotic lesions of the subclavian artery are absent. There are the following reasons for the opinion : serious surgical complications are rarely encountered, temporary occlusion of the common carotid artery is unnecessary, the cerebral blood pathway after surgery is natural, and the long-term patency rate of the anastomosis is good. On the other hand, external carotid artery-vertebral artery bypass using saphenous vein graft is the better vascular reconstruction than superficial temporal artery-superior cerebellar artery anastomosis for cases of occlusion of the vertebral artery at its origin with distal portion of the artery perfused by the collaterals.

View full abstract

Cerebral angiography is the gold standard for the evaluation of intracranial aneurysms. However, it is associated with a small but definite risk of neurological complications with a high incidence of clinically silent embolisms. On the other hand, many authors reported the clinical value of the new images acquired using magnetic resonance angiography (MRA), CT angiography (CTA) and digital subtraction angiography (DSA) for intracranial aneurysms. These 3D images have enabled a more accurate diagnosis of intracranial aneurysms than the information provided by DSA only. In our evaluation of detection methodologies for intracranial aneurysms, the accuracy of 3D-CTA is equal to or superior to that of conventional DSA, except for special cases. Although the diagnostic angiography after aneurysm surgery is useful for detecting postoperative aneurysm remnants and de novo aneurysms, 3D-CTA is the most suitable modality for the follow-up evaluation of aneurysm obliterated with a titanium clip. In endovascular surgery, 3D-DSA has been an essential tool, especially to decide the best-working angle of the C-arm. In the follow-up study of patients with aneurysms treated using Guglielmi detachable coils (GDCs), 3D-MRA is the optimal study as a noninvasive tool. According to the features and limitations inherent to each modality, neurosurgeons should devise neurological imaging modalities for the treatment of intracranial aneurysms just as they now prepare a surgical plan.

View full abstract

Acute surgery for ruptured aneurysms has been established. Residual serious complication after subarachnoid hemorrhage is symptomatic cerebral vasospasm. Because definitive treatments for cerebral vasospasm have not been developed, preventive methods are mainly performed. In this manuscript, we discussed the mechanism and incidence of symptomatic vasospasm and tried to give an outline recent reports concerning medical therapy for cerebral vasospasm. Then, our preventive method of cisternal irrigation with urokinase and ascorbic acid is reported.

View full abstract

Severe hemodynamic cerebral ischemia associated with carotid stenosis could be one of the difining characteristics of the high-risk group for carotid endarterectomy (CEA). Measurements of cerebral blood flow (CBF) and vascular reactivity in patients treated with CEA were analyzed to clarify the significance of preoperative evaluation of hemodynamic cerebral ischemia using CBF-SPECT. Both the resting and acetazolamide-activated rCBF, and the severity of the hemodynamic cerebral ischemia (Stage 0- II) were quantified using the ^123-IMP ARG method and preoperative cerebral hemodynamics were compared in both symptomatic patients (n=30) and asymptomatic patients (n=24). Postoperative improvement of resting rCBF was estimated in both groups. Stage II ischemia was quantitatively defined as both a resting rCBF of less than 80% of normal mean CBF and a vascular reserve (VR : (acetazolamide-activated rCBF/Resting rCBF-1) ×100%) of less than 10%. In the other 31 patients treated with CEA, postoperative hyperperfusion was investigated using CBF-SPECT within 24 hours after CEA. Preoperatively, Stage II ischemia (hemodynamically compromised state) was observed in 20% of symptomatic patients and 8% of asymptomatic patients. A significant difference in resting rCBF was indicated between symptomatic patients (31.8±6.1 ml/100g/min) and asymptomatic patients (37.6±6.6 ml/100 g/min) (p<0.002, t-test). Severity of hemodynamic cerebral ischemia was generally moderate in symptomatic patients. Postoperatively, a significant increase of resting CBF was observed in symptomatic patients but not in asymptomatic patients. In the other 31 patients treated by CEA, symptomatic hyperperfusion was observed in 3 of 4 patients with Stage II ischemia and asymptomatic hyperperfusion was indicated in 3 of 4 patients with Stage I ischemia with a VR of less than 10%. Preoperative CBF measurements in patients treated with CEA were significant to define severe hemodynamic cerebral ischemia (Stage II). In patients with Stage II ischemia, brain protection should be introduced using mild hypothermia with an internal shunt system in CEA, or carotid stenting could be a safer procedure. In a subgroup with Stage II ischemia, postoperative hyperperfusion should be assessed by early CBF measurement and controlled by precise management.

View full abstract

The standard methods and possible pitfalls related to endovascular therapy for atherosclerotic vertebral and subclavian arteries are introduced in this paper. The key points for endovascular therapy for vertebral arterial stenosis are as follows. (1) Stabilization of the guiding catheter, (2) minimum extrusion of the deployed stent to the subclavian artery, (3) avoid stenting for vertebral arteries smaller than 3 mm, (4) careful retrieval of the PTA balloon catheter so as not to move the deployed stent, (5) maintain the true lumen with a guidewire until the end of the procedure. The complication most frequently encountered by beginners is stent migration. It is safer to use a coronary stent if the vessel diameter is less than 4.5 mm and it is important to master how to use the Palmaz stent in larger vessels. Key points are similar to endovascular therapy for the vertebral arteries. However, special cares should be taken as follows (1) If the vertebral artery was involved in the lesion, a kissing balloon technique should be used, (2) a guiding catheter should be introduced beyond the stenosis before the Palmaz stent delivery to prevent stent migration. (3) The motion of the tip of the guidewire should be carefully monitored to identify the true lumen or pseudolumen in recanalizing the total subclavian occlusion.

View full abstract