Our treatment of arteriovenous malformations (AVMs) with Gamma Knife Radiosurgery (optimal dose treatment) showed 88.4% total obliteration in small AVMs less than 10 ml after the first treatment and very low morbidity (1.7%) in long-term follow-up (5 to 12 years). These results indicate that combined treatment is a good strategy for large AVMs in eloquent areas. Therefore, we evaluated larger AVMs treated with direct surgery including feeder clipping and/or intravascular embolization prior to radiosurgery for further development of radiosurgery of large AVMs.
Fifty of 171 patients had combined treatment (embolization: 27, direct surgery: 19, both: 4) and were followed more than 4 years and 6 months. Mean volume at the time of radiosurgery was smallest in the surgery group. Total obliteration was obtained in 94.4% of small AVMs less than 10 ml (surgery: 100%, embolization: 88.9%), although larger AVMs still have a lower obliteration rate. No lethal hemorrhages appeared after combination treatment up to date.
We concluded that radiosurgery combined with surgery and/or embolization is a safe and effective treatment for large AVMs in eloquent areas.

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There is high risk of intraoperative hemorrhage in AVM surgery due to abnormal vessels and changing hemodynamic pattern of brain. Inadequate coagulation of vessels, arterialization of veins and loss of tissue planes are major pitfalls. Preoperative embolization and temporary clipping of feeding arteries contribute to safe surgical techniques.
There were 281 patients who underwent treatment for AVM in our institution: 242 were operated (99 of them with intracerebral hemorrhage) and 39 cases were treated with embolization and/or gamma knife. Radiological evaluation was carried out by CT, dynamic and 3D-CT, MRI, fMRI, MRA, and surface anatomy scanning. Strategic image analysis and preoperative embolization were employed where feeders were behind the nidus or vein and where another craniotomy was found necessary to secure feeding arteries.
Endovascular nidus obliteration is successful only in 10% of patients. Surgical results showed risk of intraoperative bleeding in Grade 4 and 5 cases (1.5%). Recovery showed GR (205), MD (13), SD (7), PVS (2), and death (15) on 242 cases, based on Glasgow Outcome Score.
Preoperative staged nidus embolization helps prevent bleeding in large AVM; small superficial lesions have the best results with surgery. Temporary clips for feeders, good plane between nidus and brain, definition of eloquent cortex, adequate coagulation of draining veins and total nidus excision are important steps in surgical strategy.

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Subarachnoid hemorrhage is the most devastating clinical presentation of intracranial aneurysms, which makes it desirable to treat them before they bleed. Because this apoplectic event leaves most survivors with neurological deficits, we aim to define high-risk criteria for rupture based on our series.
We retrospectively analyzed 383 cases of treated unruptured aneurysms between January 1999 and December 2002, sixty-four of whom received coil embolization. Treatment indications were previous SAH, presence of bleb, symptomatic aneurysms, size more than 5 mm, posterior circulation, irregular dome wall and high-amplitude bleb-site pulsatility on 4D-CTA. Intraoperative aneurysm wall resection was performed and histological examination done.
The outcome was good in all cases after clipping and coiling; there were no cases of mortality or permanent morbidity. Immunostaining and histopathology verified loss of tunica media muscle coat and elastic lamina at the bleb site with smooth muscle actin and Type IV collagen positivity in 15 cases of aneurysm resection.
Screening with 4D-CTA or 3D-CTA are noninvasive methods that can be employed in first degree relative of SAH patients and those with risk factors. Symptomatic aneurysms need treatment as a priority; direct surgery and coiling are recommended in unruptured aneurysms. Prediction of rupture point based on 4D-CTA is confirmed histologically.

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Between November 1999 and September 2002, 175 patients with acute cerebral infarction were admitted to our Stroke Care Unit. Stroke MRI (Diffusion-, perfusion- and T2-weighted imaging and MR angiography) was performed for these patients, and we used diffusion/perfusion mismatch for indication of cardiovascular reconstruction. Of 175 patients, 44 were diagnosed as atherothrombotic infarction, 70 as cardioembolic infarction and 57 as lacunar infarction. In 19 patients (27.1%) of cardioembolic infarction and 17 (38.6%) of atherothrombotic infarction, cerebrovascular reconstructions were performed. Although outcome after treatment was good in only 3 of these 19 patients (15.8%) with cardioembolism, outcome was good in 13 of 17 (76.5%) with atherothrombotic infarction.
Outcomes of patients with cardioembolic internal carotid occlusion were very poor even if stroke MRI indicated acute thrombolysis, because almost all thrombolysis were failed. In conclusion, stroke MRI accurately diagnosed acute cerebral infarction, and acute and subacute cerebrovascular reconstruction induced good outcome in patients with atherothrombotic infarction.

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We report a case of high-position BA-SCA aneurysm operated by 2 different approaches—pterional and cranio-orbital Dolenc's approach—.
A 48-year-old woman presented with severe headache and vomiting without neurological deficit. CT scan demonstrated subarachnoid hemorrhage localized in the right Sylvian fissure. Cerebral angiogram showed right MCA ruptured and left BA-SCA unruptured aneurysms.
After clipping of the right MCA aneurysm, a left BA-SCA aneurysm was explored by the same pterional approach. However, it was impossible to clip completely because of narrow and deep operative field. Four months later, the same left BA-SCA aneurysm was well explored and clipped successfully by left cranio-orbital Dolenc's approach.
The cranio-orbital craniotomy gives a wide and shallow operative field, and Dolenc's approach gives working space around carotid artery by dissecting the distal ring and the optic canal. For the high-position distal basilar artery aneurysms, there are many reports of approaches such as zygomatic approach and extradural temporo-polar approach to complete clipping safely. The cranio-orbital Dolenc's approach is thought to be useful.

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We have treated 187 ruptured aneurysms with Guglielmi Detachable Coils (GDC) in acute Stage among 407 patients of subarachnoid hemorrhage admitted to our hospital. Of these cases, the condition of 147 patients was too poor to allow treatment. Seventy-three were treated by neck clipping. One hundred forty-six (78%) of SAH patients treated by GDCs were independent on discharge. Symptomatic vasospasm was reported in 14.7% of patients. The permanent morbidity rate is 3.5% and 2 patients died (1.4%). Although the long-term results remain to be determined, embolization with GDC is a safe and promising treatment for cerebral aneurysms.

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We report surgical treatment of 12 aneurysms located at early bifurcation of middle cerebral artery (MCA). The incidence of these aneurysms was 19.4% among 62 MCA aneurysms if the length of prebifurcation M1 of 15 mm or less was designated as the early bifurcation. Eight aneurysms were unruptured, and 4 patients presented with subarachnoid hemorrhage (SAH). The maximum diameter of aneurysms was less than 10 mm in 8 cases and 10 mm to 15 mm in 4 cases. The aneurysms were classified into 2 types: those buried deep in the sylvian fissure (Type I, 8 cases) and those projected anteroinferiorly and caged by deep sylvian veins and the sphenoid ridge (Type II, 4 cases). Small bridging veins were sacrificed in 6 cases to allow wide exposure and safe manipulation, and no venous infarction was encountered postoperatively. Surgical results were excellent in all but 1 patient with SAH where post-SAH hydrocephalus brought about some mental dysfunction. The patient was the only one who developed intraoperative aneurismal rupture.
To accomplish proximal arterial control and optimal neck clipping, meticulous dissection of sylvian fissure was important for Type I cases, whereas extensive but careful drilling of sphenoid ridge and the making of working space around the caged aneurysm were necessary in Type II cases. For the purpose, some small bridging veins were reluctantly sacrificed.

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The recent advancement of ultrasonographic imaging equipment has provided accurate visualization and characterization of the intimal plaques of the cervical carotid arteries. Because the soft plaques may easily cause embolic occlusion of the distal cerebral arteries during manipulation of the stenotic carotid arteries, it is important to predict the character of the carotid plaques for the safe PTA/STENT procedures. In this study, we examined patients who underwent carotid endarterectomy (CEA) with ultrasonographic imagings preoperatively. The macroscopic findings of the obtained carotid artery plaques and the preoperative ultrasonographic findings were compared to elucidate the diagnostic ability and clinical usefulness of the ultrasonography in this disorder.
Twelve patients with 14 lesions who underwent CEA were examined preoperatively by ultrasonography (TOSHIBA SSA370A, linear probe of 7.5 MHz). There were 10 men and 2 women, aged from 64 to 73 years. Ultrasonographic findings of the plaques could be classified as “hyper,” “iso,,” “low,” or “mixed,” intensity by the character, and as “smooth,” or “irregular,” plaques by the configuration. The perioperative macroscopic findings of the plaques were characterized as “fragile,” or “tough.,” The ultrasonography showed 3 lesions with low intensity and 4 lesions with mixed intensity, including low intensity. These 7 lesions were fragile in the macroscopic findings. Five lesions showing iso intensity by the ultrasonography did not include fatty degeneration or internal bleeding of the plaques and were judged as tough plaques. The ultrasonography was able to detect an ulcer of plaque.
Micro embolisms such as the fat in plaque or the thrombus can occur in the operation, and it is said that the complications of the cerebral embolisms caused by them are a serious problem of PTA. The exclusion of the high-risk group by ultrasonography examination is the most important factor in doing PTA/STENT safely. From the findings by ultrasonography and the perioperative macroscopy, we can classify “safety,” or “danger,” in each plaque to perform PTA/STENT.
We judged the fragile plaques too dangerous for PTA/STENT. We can fully satisfy the character diagnosis of the carotid plaques by ultrasonography in estimating the safeness for the intravascular operation. The probability that complications by micro embolisms occur will be high when performing PTA/STENT in low-intensity plaques. We should exclude such cases from indication of PTA/STENT in future.

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Recently, PTA/stenting for intracranial atherosclerotic stenoses has been reported as a treatment option. We describe clinical results of PTA/stenting for 87 patients of intracranial atherosclerotic stenoses (88 lesions). The procedure was performed under local anesthesia via percutaneous transfemoral route. In 61 patients, we performed PTA only and used stent in 26 patients. In 87 patients, technical success rate was 97% and the mean stenosis rate before PTA/stenting, 77.0%, decreased to 25.4% after the procedure. In particular, 26 cases of stenting showed remarkable improvement of the mean stenotic rate (77.7% to 5.5%). The morbidity, neurological deficits at 30 days and mortality rate was 10.3%, 6.9% and 2.3%, respectively. The ischemic complications such as cerebral embolism, dissection, and stent thrombosis occurred, while there were hemorrhagic complications such as intracranial bleeding due to hyperperfusion, rupture of associated intracranial aneurysm and cerebellar hemorrhage caused by bleeding tendency. In addition, the restenosis after stenting tends to occur less than that PTA only.
Because of the high morbidity and mortality rate compared with the procedure for extracranial lesions, PTA/stenting for intracranial arterial stenoses may require stricter indications and the prevention from predictable complications of this procedure. Long-term follow up and study of the natural history of the intracranial atherosclerotic stenoses seem to be important to establish this treatment.

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We evaluated the role of short-latency somatosensory evoked potentials (SSEP) in aneurysmal subarachnoid hemorrhage (SAH).
In this retrospective study, we investigated 102 patients recording SSEP within 24 hours of SAH, including 30 patients in Grade I, 21 in Grade II, 18 in Grade III, 13 in Grade IV and 20 in Grade V on W.F.N.S. Scale.
SSEP patterns in patients with SAH were ranked from I to V according to the central conduction time (CCT), the time between the N14 peak (recorded at C-2) and the N20 peak (recorded at the cortex) in response to median nerve stimulation on either affected or unaffected side. Outcome was determined according to Glasgow outcome scale.
The prognostic value of SSEP was statistically confirmed (p value=0.007). In particular the pessimistic prognosis was accurately predicted by poor SSEP grade, although optimistic prognoses could not necessarily be predicted by a good SSEP grade.
Successive recording of SSEP showed that the CCT in the patients with symptomatic delayed vasospasm tended to prolong even in the early period as well as the CCT prolonged with developing delayed vasospasm.
SSEP was a useful clinical indicator of aneurysmal SAH.

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As much as 20% of the P2-P3 aneurysms are fusiform, thrombosed, and giant types and since an intimate relationship is present between the cranial nerves and upper brain stem, the surgical approach and dissection of the P2-P3 aneurysm is technically challenging. We present 3 cases of P2-P3 partially thrombosed giant aneurysms treated by means of each procedure. Case 1 involved a P2 aneurysm, and successful clipping was performed using circulatory arrest with profound hypothermia. The perforating branch was preserved. Case 2 involved a P2-P3 aneurysm, and surgical ligation of the P2 proximal to the aneurysm was performed because the parent artery was totally thrombosed. Case 3 involved an aneurysm of the P3 segment, and parent artery occlusion was performed using microcoils after selective P3 balloon occlusion test. All patients had either an excellent or good outcome. These operative approaches and procedures should be discussed in relation to the anatomy of P2-P3 aneurysms.

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