Reinforcement or wrapping is frequently used to treat an unclippable fusiform aneurysm. However, reinforcement does not eliminate the aneurysm and therefore does not guarantee the prevention of bleeding or progressive growing of the aneurysm. Recently, we used a modified wrapping technique, including a clip-reinforced cotton sling to treat an incidental fusiform aneurysm at the P2 segment of the left posterior cerebral artery. The postoperative course was uneventful. Three months later, however, left-side oculomotor palsy developed, and angiograms showed a marked enlargement of the previously treated aneurysm. We suspect that the growing mechanism is related to changes in the properties of the aneurysmal wall after clip-reinforced wrapping. After clip-reinforced wrapping, the aneurysm becomes less flexible and experiences a greater wall stress. Therefore, if wrapping does not cover the full length of a fusiform aneurysm, the uncovered weak part of the aneurysmal wall may expand because of the increased wall stress.
This clip-reinforced wrapping technique, though more reliable than the traditional wrapping technique, may induce a postoperative enlargement of fusiform aneurysms if incompletely performed.

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We have experienced 4 patients who had aneurysms lacerated iatrogenically at their necks. In all cases, too steep shearing forces to the neck was the cause of neck lacerations, and closure of torn aneurysmal necks with 1 to several stitches under the complete occlusion of the parent arteries was effective.
One of the causes of neck lacerations is thought to be intraaneurysmal thrombosis of the aneurysm as well as the bursting of aneurysms that were plugged by thrombus at their rupture point. We experienced 11 such unusual aneurysms that the initial angiogram indicated did not exist or were small. Lowering the intraaneurysmal pressure by temporary clipping is necessary to prevent neck laceration.

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The dorsal internal carotid artery aneurysm (IC-dorsal An) needs careful attention during clipping.
We report a case of a small ruptured IC-dorsal An in a 74-year-old woman, who presented with a subarachnoid hemorrhage. At surgery, the aneurysm looked clippable. When the dome was being fully exposed after clipping, the clip slipped out and massive bleeding occurred. With the bleeding point covered by a cotton patty and a tapered brain spatula, the anterior clinoid process was drilled and the dural ring was dissected to expose the proximal side of the internal carotid artery. The aneurysm was then wrap-clipped.
The IC-dorsal An, in many instances, should not be clipped, but wrap-clipped, as the wall of the aneurysm is quite thin, including the neck itself. We present a useful method—the reverse compression method—for an unexpected intraoperative rupture of the internal carotid artery.

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A 58-year-old male suffered from diffuse and symmetric subarachnoid hemorrhage with Hunt and Kosnik Grade II. Angiography demonstrated 3 aneurysms. The largest was located at the basilar artery (BA) tip with a size of 18 mm ×15 mm ×14 mm and thought to have a small bleb. The 2nd largest was located at the left middle cerebral artery (MCA) bifurcation and showed an irregular shape with a maximum diameter of 5 mm. The smallest was at the right MCA bifurcation and showed a round shape with a maximum diameter of 3 mm. One of first 2 was thought to be ruptured, and we first treated the left MCA aneurysm by surgical clipping and confirmed it was unruptured. Immediately after clipping, we performed intraaneurysmal embolization of BA tip aneurysm using GDC.
The result of embolization was a neck remnant with a volume embolization rate of 19.3%. The patient was discharged without any neurological deficit and continued oral anti-platelet drug for 6 months. Follow-up angiography 6 months later demonstrated enlargement of the remnant neck. Re-embolization was performed 8 months after initial embolization. At that time we planned the embolization with the help of neck plasty technique using two the balloons, but we could introduce the balloon microcatheter only into the right posterior cerebral artery (PCA). The result was again a neck remnant. Follow-up angiography was performed 6 months, 12 months, and 24 months after re-embolization, and the neck remnant was enlarged every time. Because re-embolization was technically difficult, we hesitated to perform a third embolization. Follow-up angiography at 36 months, however, showed large ballooning of the aneurysmal body, which made us decide to perform the third embolization. At the third embolization, immediately after introduction of balloon microcatheter into the left PCA, the BA was suddenly occluded. The BA was not recanalized any more in spite of fibrinolysis using tissue-type plasminogen activator. The patient died 5 days later.
Appropriate case selection, including size of aneurysm, timing of embolization and probability of complete obliteration is essential for coil embolization. Performing embolization on inappropriate patients may result in poor control of the aneurysm complicate further treatment.

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Recently, PTA/stenting for cervical internal carotid artery (ICA) stenoses has been performed, especially in high-risk patients of carotid endarterectomy, despite unresolved problems, such as distal embolism. We report clinical results and complications of PTA/stenting for cervical internal carotid artery stenoses, and introduce our technique using blocking balloon catheter systems (BBCS) for safe and effective PTA/stenting.
We treated 118 patients with cervical ICA stenosis by PTA or stenting. In 21 of 55 cases in which only PTA was done and in 48 of 63 cases in which stenting was performed, we used our BBCS to prevent distal embolism. Angiography, MRI and CT scan were utilized to detect infarcts due to distal embolism. In 20 lesions, diffusion-weighted MRI was performed to detect embolism in detail.
The total morbidity and mortality rate was 5.1% and 0%, respectively. Morbidity at 30 days after treatment was 2.5%. Three patients had neurological deficits, 2 of whom had infarcts due to distal embolism and 1 of whom had intracerebral hematoma due to hyperperfusion. In patients of stenting with BBCS, morbidity at 30 days was 0%. In 15 lesions treated by stenting using BBCS at postdilatation, new hyperintense areas after PTA/stenting were detected in 7 lesions (47%) on diffusion-weighted MRI, but only 1 patient had symptoms. To reduce distal embolism further, we now use BBCS and dilate the stenosis sufficiency at predilatation, and postdilatation is not added when a significant stenosis does not remain. For safe and effective PTA/stenting, (1) careful neuroradiological evaluation, (2) prudent placement of a large guiding catheter, (3) careful manipulation of microguidewire for advancement through the severe stenosis, (4) use of BBCS at predilatation as well as at postdilatation and (5) use of sufficient size of a PTA balloon at predilatation seemed to be neccessary.
Our BBCS is a useful device to decrease the rate of symptomatic distal embolism in clinical results without increasing the total complication rate.

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It is important to preserve perforators of the anterior communicating artery (A-com) such as the hypothalamic artery in surgery of the A-com aneurysm (A-com AN). Preservation of these arteries is, however, sometimes difficult in the limited space of the small surgical field. We report the efficacy of a technique that provides a wide surgical field by our modified interhemispheric approach (IHA).
During the past 5 years, we have experienced 78 cases with A-com AN. We selected 34 cases (44%) to apply IHA according to the results of the angiography and three-dimensional CT angiography.
To obtain a wider view and surgical field around A-com AN, the falx is completely resected at its anterior end, the olfactory nerves are completely dissected to free them from the base of the frontal lobe by meticulous arachnoid dissection, the arachnoid membrane is opened even at the Sylvian vallecula as well as at the portion of the bilateral internal carotid artery to the A-com through the horizontal part of the anterior cerebral artery (A1). After these preparations, we open the interhemispheric fissure from the corpus callosum to the frontal base.
Our modified IHA made it possible to preserve perforators thoroughly with a much wider surgical field around the A-com than that with the usual pterional approach or traditional IHA. Our modified IHA provides enough space even when using temporary clips for A-com ANs that are relatively difficult to dissect, such as big and/or complexly shaped aneurysms with tight adhesion of surrounding arteries, enabling application of aneurysmal clips from various directions and ensuring safe and complete obliteration of the aneurysmal necks.
Our modified IHA is especially useful in the surgical intervention of big and complexly shaped A-com ANs.

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We studied the regional cerebral blood flow on patients with severe stenotic lesions of internal carotid arteries or the M1 trunk of the middle cerebral artery by the Patlak plot method with ^99mTc-SPECT, and evaluated the difference between ^99mTc-ECD and ^99mTc-HMPAO. The mean±SD of the regional cerebral blood flow calculated with ^99mTc-ECD in the healthy side and affected side at rest was 37.2±5.0 and 33.4±8.3 ml/100 g/min, and that after acetazolamide administration was 42.5±9.2 and 36.0±10.9, respectively. The flow calculated with ^99mTc-HMPAO in the healthy side and affected side at rest was 41.2±6.7 and 37.4±6.1 ml/100 g/min, and that after acetazolamide administration was 52.0±11.1 and 44.3±9.7.
Although the flow in the affected side at rest was not significantly changed after the superficial temporal artery-middle cerebral artery anastomosis, the vasoreactivity in the side showed marked improvement.
This noninvasive simple method for quantitative evaluation of regional cerebral blood flow and vasoreactivity to acetazolamide is very useful in routine clinical studies.

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Revascularization treatment for occlusion of the intracranial artery is effective, but the outcome is still poor or sometimes death in patients with occlusion of the cervical internal carotid artery. We investigated the indications and limitations of percutaneous revascularization for cervical internal carotid artery occlusion.
Five patients with atherosclerotic occlusion (thrombosis) and 7 patients with embolic occlusion (embolism) were admitted within a few hours of onset and treated with local thrombolysis and percutaneous transluminal angioplasty (PTA). Angiographical examination was performed before treatment using a bolus of contrast material injected just distal to the occlusion via a microcatheter passed through the area.
All cases of thrombosis were successfully revascularized, but 1 patient suffered reocclusion by the next day. Carotid endarterectomy (CEA) and stenting were performed in 1 case each. Two cases of embolism remained stationary, and 5 cases of embolism were complicated by migration to the distal internal carotid artery or middle cerebral artery. The outcome was good recovery in 3 patients with thrombosis and no deaths, whereas all patients with embolism had moderate disability or worse, and 3 died.
Emergency percutaneous revascularization is indicated for the treatment of thrombosis. Recanalization is potentially effective when performed with the combination of thrombolysis and PTA. Postoperative care is required to prevent subsequent reocclusion, and CEA or stenting can be performed later. In contrast, percutaneous revascularization may not be indicated for the treatment of embolic occlusion, because of the risk of collateral circulation damage.

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We performed intraaneurysmal embolization using Guglielmi detachable coils (GDCs) for cerebral aneurysms, and we report here on the selection of an embolization technique based on the aneurysmal neck diameter. Intraaneurysmal embolization was attempted on 47 patients (48 aneurysms), aged between 33 and 89 years (mean 65.5 years), from March 1997 to March 2001.
In this series, we considered the wide-necked aneurysm as an aneurysm with a neck diameter of 4 mm or more, and/or with a neck-to-fundus ratio of greater than 1.0. In 8 wide-necked aneurysms, neck plasty was performed employing a balloon or stent-assisted technique to prevent coil protrusion into the parent artery. Forty-seven cases who could undergo intra-aneurysmal embolization were classified into the following groups: 1) small aneurysm (<10 mm)/small neck (<4 mm) (S/S group): 26 aneurysms; 2) small aneurysm/wide neck (S/W group): 18 aneurysms; 3) large aneurysm (10-25 mm): 2 aneurysms; and 4) giant aneurysm (>25 mm): 2 aneurysms. Complete occlusion (95-100%) was achieved immediately after coil embolization in 19 aneurysms (73%) of the S/S group and in 12 aneurysms (63%) of the S/W group.
In 1 of the 2 large aneurysms, complete occlusion was achieved, and dome filling was observed in the other. This dome filling was also noticed in both giant aneurysms. Balloon-assisted technique was performed in seven aneurysms with wide necked leading to complete occlusion in 6 aneurysms. Follow-up angiography over a mean period of 13 months confirmed the complete occlusion in these 6 aneurysms. The use of the stent-assisted technique for large aneurysms produced complete occlusion, and the parent artery was preserved. During the 2-year follow-up period, no coil compaction was observed. The complications included aneurysm rupture during the procedure in 2 patients and occlusion of the peripheral arteries in 2 patients, but no permanent neurological deficits related to coil embolization were observed.
It is very likely that the conventional embolization techniques can achieve complete occlusion for small aneurysms with small necks. For wide-necked aneurysms, however, neck plasty using a balloon or stent provides satisfactory therapeutic results.

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The goal of this study was to define treatment results of gamma knife radiosurgery (GKS) for arteriovenous malformation (AVM) located in the sensorimotor cortex. We analyzed 27 patients followed up for at least 12 months. The onset of AVM was convulsion 10, clinical hemorrhage 7, neurological deficits 4, and headache 3. The mean diameter of the AVM nidus was 22.2 mm (range 8.5-33.6 mm) and mean volume was 7.4 ml (range 0.32-19.9 ml). According to the Spetzler-Martin scale, the AVMs were Grade II in 13, Grade III in 10, and Grade IV in 4 of the patients. GKS was performed with a mean dose of 19.0 Gy (range 14-25 Gy) to the margin of the nidus. The mean follow-up period was 29 months (range 12-72 months). Six AVMs showed complete obliteration angiographically and 5 AVMs showed obliteration on magnetic resonance image. Sixteen AVMs showed nidus shrinkage. Eight (53%) of 15 patients followed up for more than 24 months showed obliteration. Complications consisted of 3 (11.5%) of 27 patients with evidence of radiation injury to the brain parenchyma. Symptoms of slight hemiparesis resolved completely in all patients within several months.
GKS is a useful and safe treatment also for AVM located in the sensorimotor cortex.

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There are 2 approaches to perform clipping of anterior communicating aneurysms: the pterional and the interhemispheric approach. The pterional approach is often applied as for anterior communicating aneurysms. We have used the interhemispheric approach for all anterior communicating aneurysms for 10 years. The interhemispheric approach is difficult to employ without injuring pia matter or pial capillary vessels, if the operator does not know the microanatomy of interhemispheric fissure in detail or does not have precise and stabile microsurgical technique. Itoh et al. described an interhemispheric approach in 1983 in which they recommended a 3-step procedure in the dissection of the interhemispheric approach. In the first step, the pericallosal cistern should be exposed, in the second step the arachnoid trabecullae between both cingurate gyruses are dissected, and in the third step, the bilateral gyrus rectus should be separated, exposing the aneurysm. The advantage of the interhemispheric approach is that operators can identify the complete microanatomical structures of the anterior communicating artery complex and surrounding microstructures like hypothalamic arteries. We describe the key points of the interhemispheric approach in detail.

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