We discuss options, techniques, pitfalls, and risk and benefits of surgical treatments for dissecting vertebral aneurysms involving the posterior inferior cerebellar artery (PICA). Our discussion is based on recent experience of 12 cases over a 5-year period of direct trapping for ruptured aneurysms with/without PICA involvement in the acute stage. Three aneurysms involving the PICA were treated in the first stage by direct trapping and PICA revascularization, of which 1 was a side-to-side VA-PICA bypass. The other 2 were OA-PICA bypasses.
Five of 6 patients (89%) of SAH Grade 1 or 2 had an excellent outcome (GR). Cranial nerve injury or ischemic complication of perforators might occur in a few cases, and the outcome could depend on SAH grade.
We conclude that direct trapping and simple revascularization for the PICA may be the best treatment for a dissecting vertebral artery involving the PICA.

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Ruptured vertebral artery dissecting aneurysm (VADA) requires urgent treatment because of the high incidence of re-bleeding, especially during the first 24 hours. Among such cases lesions involving the origin of the posterior inferior cerebellar artery (PICA) are formidable because it is difficult to prevent rebleeding and preserve blood flow of the PICA in the acute stage.
We report a representative case in which we tried a simple and effective therapeutic method for these cases. A 38-year-old man was admitted to our hospital suffering severe headache, vomiting, and loss of consciousness. CT scan revealed subarachnoid hemorrhage, but soon after, rebleeding occurred and he fell into a deep coma. After waiting until the chronic stage when he recovered, we performed cerebral angiography. A left vertebral angiogram demonstrated a dissecting aneurysm involving the origin of the PICA. We occluded the affected vertebral artery (VA) near its root with platinum coils, intending to introduce collateral blood flow from the deep cervical artery into the VA trunk. We thought the controlled antegrade VA flow and retrograde flow from the contralateral VA would make a watershed at the dissecting aneurysm, which promotes thrombosis of the pseudo-lumen while preserving the antegrade flow of the PICA. After treatment, the dissecting aneurysm disappeared on angiogram and the patient recovered without rebleeding or ischemic complication. This method should be considered as the treatment of choice in cases with VADA involving PICA.

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We review cerebral hyperperfusion following carotid endarterectomy (CEA).
Persistence of cerebral hyperperfusion greater than several days after CEA is associated with development of hyperperfusion syndrome. Postoperative cerebral hyperperfusion, even when asymptomatic, is associated with impairment of cognitive function in patients undergoing CEA. Further, development of hyperperfusion syndrome is associated with persistent postoperative cognitive impairment. Pretreatment with a novel free radical scavenger—edaravone—prevents occurrence of cerebral hyperperfusion itself after CEA. Intraoperative monitoring of transcranial regional cerebral oxygen saturation using near-infrared spectroscopy or monitoring of intraoperative middle cerebral artery blood flow velocity using transcranial Doppler ultrasonography identifies patients at risk for hyperperfusion after CEA. Reduced preoperative cerebrovascular reactivity to acetazolamide is a significant independent predictor of post-CEA hyperperfusion.

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Our treatment strategy for vertebral artery dissection is to embolize the aneurysmal dilatation as a part of the dissecting pseudolumen, followed by obliteration of the entry and proximal true lumen of the vertebral artery. We report on 9 patients with a total of 10 vertebral artery dissections. The patients comprised 6 men and 3 women, ranging in age from 31 to 72 (mean, 49.7). Six patients presented with subarachnoid hemorrhage and 3 with headache. The dissecting lesions were located proximal to the posteroinferior cerebellar artery (PICA) in 1 and distal to the PICA in 4. The PICA was involved in 1 and was not visible on angiograms in 4. Angiographic findings included 8 lesions extending near the union and 5 that were longer than 15 mm.
Under general anesthesia, 2 guiding catheters were placed into both vertebral arteries, and the microcatheter was introduced into the aneurysmal dilatation, which was then embolized with GDC 10, followed by embolization of the entry and the normal lumen in the proximal vertebral artery. During occlusion of the aneurysmal dilatation, it was very important to gently place the GDC 10, which was smaller than the diameter of the aneurysmal dilatation, to loosely pack. For 2 long dissections, the microcatheter could not reach the distal part of the aneurysmal dilatation via the ipsilateral approach, because of complex structure of pseudolumen or several entries into the aneurysmal dilatation. In these cases, another microcatheter was introduced into the residual part of the dilatation through the union via the contralateral vertebral artery, resulting in complete occlusion of the lesion. In 1 case of a lesion involving the PICA as a contralateral dissection of the ruptured one, coiling with stent caused acute occlusion of the vertebral artery without neurological deficits. Another 3 embolization procedures were added to completely occlude the dissection with the patency of the PICA. Neurological deterioration due to medullary infarction postoperatively occurred in 1 patient as a possible complication.
Embolization of aneurysmal dilations for vertebral artery dissections, followed by occlusion of the entry and proximal vertebral artery resulted in curative results to prevent hemorrhage and an increase of aneurysmal size. When the microcatheter could not be introduced into the distal part of the aneurysmal dilatation, the contralateral approach should be combined to completely occlude the dilatation. In the near future, the flexible intracranial stent could be applied for the treatment of vertebral artery dissections.

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We review our recent experience of carotid endarterectomy (CEA) for 30 patients with severe carotid artery stenosis. In this report, we emphasize the importance of critical management before, during, and after surgery to reduce or remove the incidence of perioperative complications. Especially, we should carefully manage the patients who are at higher risk for hyperperfusion syndrome and those with complications of serious coronary artery disease. We also describe our surgical technique and results.

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Recent advances in intravascular surgical technique have made it possible to choose transvenous embolization (TVE) as the first therapeutic procedure of cavernous sinus dural arteriovenous fistula (CdAVF). While the inferior petrosal sinus (IPS) is the most common approach route to the cavernous sinus (CS), embolization through the IPS is difficult in some patients. We report 3 cases who underwent TVE via IPS and latter required additional TVE via another approach.
Subjects were 3 of 16 patients with CdAVF who underwent TVE at our institution in the past 6 years. Case 1 had bilateral CdAVF (the right side was more severe). Initially, TVE was performed through the left CS via the intercavernous sinus (intCS) from the right IPS, and the posterior component of the right CS was occluded at the end. This partial embolization of the right CS induced increase of reflux to the right superior ophthalmic vein (SOV) causing exacerbation of proptosis on the right side. Transarterial embolization via the ascending pharyngeal artery decreased reflux to the right SOV immediately. TVE through the SOV was undertaken 1 week later and the fistula was completely occluded. In Case 2, embolization was performed through the patent IPS. During TVE, the coil accidentally became detached, and another coil was placed from the contralateral CS via the intCS. Reflux to the SOV diminished transiently, but recurred because the IPS, one of the outflow paths, became occluded. Hence additional TVE via the SOV was required to completely occlude the fistula. In Case 3, although the CS could be reached from the IPS, the venous pouch in which the fistula had occurred could not be reached due to trabeculae within the CS. TVE by the direct puncture of SOV successfully occluded the fistula.
When treating CdAVF by TVE, it is necessary to not only carefully ascertain the location of the fistula and ensure thorough packing but also to utilize multiple approaches and combine TAE as necessary.

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Pseudo-occlusion of the internal carotid artery has been subdivided from carotid near occlusion, and defined as a more severely stenosed group. Angiographic characteristics of pseudo-occlusion include “string like” residual filling of the internal carotid artery (ICA) beyond the carotid bifurcation, and retrograde filling of the ICA via the ophthalmic artery reaching the skull base.
Eight patients with pseudo-occlusion were treated with carotid endarterectomy. Clinical features, radiological findings, and operative records were retrospectively examined. Four patients presenting progressing strokes and 1 presenting minor stroke were treated in an acute period, and 2 patients presenting minor strokes and 1 presenting transient ischemic attack (TIA) in a chronic period after their last ischemic attack. All patients had suffered from recent TIA confined to the ipsilateral carotid artery territory.
The pattern of ischemic brain lesions evaluated by means of computed tomography and magnetic resonance imaging revealed that most of the subjects had a hemodynamic pathogenesis. Ischemic brain lesions suggesting embolism were also found in 2 cases in an acute period. CEA was successfully performed in all patients. Intraoperatively, a patent but collapsed ICA distal to a localized atheromatous plaque was recognized in all cases.
CEA is benefit for patients with pseudo-occlusion of the internal carotid artery.

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To elucidate the natural clinical course and identify radiological changes of non-hemorrhagic dissecting aneurysm, we retrospectively reviewed the cases of 10 patients with non-hemorrhagic dissecting aneurysms. Their clinical course had been followed for 1 month to 11 years 7 months (mean: 3 years 2 months), and cerebral angiography and/or magnetic resonance (MR) angiography findings examined for 3 weeks to 10 years 1 month after initial onset. The site of the dissection involved 8 vertebral arteries, 1 internal carotid artery and 1 anterior cerebral artery. Initial symptoms were headache in 3 cases, headache with motor weakness in 2 cases, headache with dysarthria in 1 case, headache with dizziness in 1 case, and Wallenberg Syndrome in 1 case. The remaining 2 cases were diagnosed incidentally.
Following initial conservative treatment, intravascular treatment was performed in 2 cases whose dissecting aneurysms increased in size after 7 to 7.5 months. Follow-up symptoms were no symptoms in 8 cases, dizziness in 1 case and hypertensive intracerebral hemorrhage in 1 case. Serial cerebral angiograms and/or MR images showed radiological changes in 7 cases, observed from 1 month to 2 years 4 months after initial onset.
These findings suggest that initial conservative treatment resulted in relatively good clinical outcome in patients with non-hemorrhagic dissecting aneurysms, but surgical intervention should be performed when dissection increases. In addition, patients with non-hemorrhagic dissecting aneurysm should be carefully followed by cerebral and/or MR angiography until 1 or 2 years postonset.

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We evaluated the cases of 32 consecutive patients with ruptured vertebral artery dissecting aneurysm (VADA) treated in our institution during the last 4 years. The goal of treatment was to exclude the aneurysm from the circulation using Guglielmi detachable coils (GDC). Twenty-six out of 32 patients were treated within 24 hours of the initial rupture, but 17 had rebleeding before treatment.
The outcome of the patients depended greatly on the patient's condition (Hunt & Kosnik grade) before treatment and whether there was rebleeding. There were 4 complications including 1 case of intra-operative rupture, 2 cases of rebleeding after treatment, and 1 case of cerebral infarction. The lessons from these complications would benefit from further treatment.
Although this report does not describe a controlled study, we found that endovascular treatment is preferable for treating ruptured VADAs in the acute stage.

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We report 2 cases with giant/large thrombosed aneurysm. One patient, who presented with subarachnoid hemorrhage, had a giant thrombosed aneurysm of the middle cerebral artery and underwent surgery. To prepare for the parent artery occlusion, a STA-MCA bypass was set and motor evoked potential (MEP) was monitored. The aneurysm was cut open, the thrombus was removed, and clipping was performed. Another patient, who presented with visual disturbance, had a large thrombosed aneurysm of anterior communicating artery, which occupied the tubercullum sellae. The aneurysm was clipped after removal of the thrombus.
Since the wall of a thrombosed aneurysm is too hard to clip, the thrombus must be removed before clipping. To prevent premature rupture, a thrombus should be carefully removed, paying attention to the nature of the thrombus.
In preparation for parent artery occlusion, installation of bypass and MEP monitoring is effective. Even after setting a bypass, the blood flow to the perforating arteries should be carefully monitored with MEP.

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Surgery of cerebral aneurysm confronts expected difficulty and unexpected happenings. To make difficult surgery easy, a surgical strategy as if operating in a shallow basin with the skull base technique is required. Extradural drilling of the anterior clinoid process is the most basic technique to obtain wide working space by mobilizing the internal carotid artery. We report a case of very high-positioned basilar top aneurysm treated with this technique. Drilling of the anterior clinoid process is a safe and quick technique. On the contrary, drilling of the posterior clinoid process poses the danger of unexpected massive bleeding from the venous plexus of the clivus. Preoperative estimation of how wide and deep the drilling can be performed is not easy. Hesitating go and obligatory stop limit this technique. We report 2 cases that encountered this situation.

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