For the treatment of patients with complex internal carotid artery (ICA) aneurysms, it may be necessary to occlude the parent artery following a bypass surgery. The bypass surgery may be low or high flow bypass, but selection criteria have not been established. We retrospectively analyzed our method using preoperative balloon test occlusion (BTO).
Thirty-five patients with ICA aneurysms, 15 ruptured and 20 unruptured, were treated with parent artery occlusion with bypass surgery. Preoperative BTO was performed in 27 cases (all unruptured and 7 ruptured, chronic stage cases). When ischemic symptoms occurred during BTO, high flow bypass was performed followed by parent artery occlusion. Otherwise, single-photon emission computed tomographic findings during BTO were used for the bypass selection. If ipsilateral residual blood flow was 70-75% or less of the contralateral hemisphere, high flow bypass was chosen and if between 70-75% and 90%, superficial temporal artery-middle cerebral artery (STA-MCA) bypass was employed. In the acute stage of 8 ruptured cases, BTO was not performed and bypass selection was made according to angiographic findings only. After completion of the bypass, ipsilateral ICA occlusion (ICO) was performed either by direct or intravascular technique. The site of ICO was determined to completely block the blood flow into the aneurysm considering both conventional angiography and BTO findings.
A total of 15 STA-MCA and 20 high flow bypasses were performed followed by ICO. There was no mortality or morbidity in unruptured cases. In ruptured cases, there were 3 complications related to surgical procedure such as perforator injury, but no patients showed insufficient ipsilateral cerebral blood flow postoperatively. One asymptomatic cerebral infarction developed due to BTO. In 5 cases, petrous portion collateral flow from external to internal carotid artery was seen, and the ICO was performed above the collateral using intravascular embolization.
In patients with complex ICA aneurysms to be treated with bypass surgery and ICO, BTO may provide a reliable tool to determine the bypass method and the site of ICO.

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We review our recent results in 18 patients with asymptomatic severe (75%<) carotid artery stenosis complicated with coronary, valvular, or aortic disorder that requires surgical treatments. According to our treatment protocol, 4 patients underwent carotid endarterectomy (CEA) and coronary artery bypass graft (CABG) or off-pump CABG (OPCABG) simultaneously. Ten patients underwent 2-staged therapy including CEA or carotid artery stenting (CAS) and cardiovascular surgery. CEA following OPCABG was selected in 2 patients with 75% carotid artery stenosis. Two other complicated patients required 2-staged cardiovascular surgery combined with CEA or 3-staged therapy comprising CAS, CEA, and OPCABG. Overall morbidity and mortality was 11.1% and 5.6%, respectively.
Based on our 5-year experiences, we emphasize the importance of thorough multidisciplinary discussion, informed consent, and a skilled team in treating the patients with complicated carotid and coronary artery disorders.

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We have performed carotid artery stenting (CAS) for 327 patients with ICA stenosis in our institutes using various embolic protection devices since 1997. After establishment of embolic protection methods in 1999, we have performed CAS for 114 asymptomatic carotid stenosis of more than 60%, according to the criteria of ACAS trial.
In this paper, we report our initial results (perioperative complication, morbidity/mortality at 30 days after CAS, changes in stenosis ratio), rate of re-stenosis, and midterm results in cases followed more than 3 years after CAS. The mean preoperative stenosis ratio, 75.6%, remarkably decreased to 5.6% after CAS. The morbidity/motality rate at 30 days after CAS was 0.8% (1/114 cases). In 22 cases, followed up more than 3 years after CAS, no ipsilateral ischemic stroke was encountered.
CAS for asymptomatic carotid stenosis is an effective and safe treatment to alleviate stenosis and prevent future ischemic stroke as well as carotid endarterectomy (CEA). Randomized controlled trials, based on the natural history of carotid stenosis, are needed in the near future to establish the indication of CAS for asymptomatic carotid stenosis.

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The efficacy of intraoperative neurophysiological monitoring in vertebro-basilar artery aneurysm (VB-AN) was clinically examined. Since June 2001, intraoperative monitoring was performed in 12 operations for VB-AN. Five operations were for vertebral artery aneurysms: 4 through the lateral suboccipital route and 1 endovascular surgery. Among 5 operations for basilar bifurcation aneurysms, 3 were through the subtemporal route and 2 were by the anterior temporal approach. The other 2 operations were for the posterior cerebral artery aneurysms by the subtemporal approach. Auditory brain stem responses (ABR) were recorded in 5 operations, somatosensory evoked potential in 1 operation, and motor evoked potential (MEP) in 9 operations by 7 of 300～600 (400 in general) V bipolar transcranial (TC) stimulations or 7 of 3～10 mA brain stem direct (BSD) stimulations. In 5 operations, both TCMEP and BSDMEP were used together. Glasgow outcome scales of 12 patients were divided into 6 good recoveries, 2 moderate disabilities, 3 severe disabilities and 1 persistent vegetative state. Among 3 patients with BA aneurysms who had a significant decrease or disappearance of the amplitude of MEP by the temporally occlusions of the BA or both VA, 2 patients have never suffered from the prolonged motor palsy. ABR monitoring seems to be essential in the operation by lateral suboccipital approach since it is very easy and sensitive. It is also applicable in endovascular surgery. TCMEP seems to be useful in VB-AN surgery in which the primary motor cortex connot always be exposed. BSDMEP was successfully recorded in 5 of 7 operations tried and it seems to be a more effective way to monitor motor functioning than TCMEP.

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In surgical procedures to dissect the sylvian fissure, the fissure is commonly unfolded by the attachment of all sylvian veins to the temporal lobe. During this procedure, cerebral edema and contusion in the frontal lobe are often caused by sacrificing bridging veins from the frontal lobe and excessive retraction on the frontal lobe. In this procedure, some sylvian veins must be kept on the side of the frontal lobe to preserve the bridging vein. In many cases, detachment of the sylvian vein from the surface of the temporal lobe is required. The sylvian vein can be detached from the temporal lobe using the space around the temporal artery right under the sylvian vein.
For detachment of adhesions between the frontal and temporal lobes, a “paper knife technique” is available in which a surgical site is generated by cutting upwards from the subarachnoid space around M1. In a “denude technique,” a wide surgical field can be obtained with less retraction of the frontal lobe by detaching the arachnoid membrane from the sylvian vein and thus allowing venous extension. During dissection of the sylvian fissure, arteries and veins belonging to the temporal lobe spread while adhering to the frontal lobe. In this case, the site to dissect is the frontal-lobe side where the vessels are located, even if the sylvian fissure is widely unfolded. Conversely, when cerebral vessels belonging to the frontal lobe are attached to the temporal lobe, the site to dissect is on the temporal lobe side, where the vessels are located. Thus the concept of a “microvascular sylvian fissure” in which detailed vessel structures are captured at a microscopic level is important in terms of preventing damage to blood vessels, pia matter and brain tissue. It is crucial to obtain a large surgical field and confirm where blood vessels belong.
To detach an aneurysm attached to arteries such as M2, A2 or perforating arteries and deep veins, without causing damage, using the tip of micro-forceps for microvascular anastomosis as a raspatory is useful. Other detailed technical ideas are introduced. These include: pulling the aneurysm into the surgical site by transposing the artery and aneurysm using brain spatulas, silk threads, and Aron alpha to confirm adjacent vascular structures such as perforating arteries; using a “double-clip technique” to confirm complete clipping with 2 clips; and deliberately shifting the bayonet clip to preserve perforating arteries.

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To determine the efficacy of mild hypothermia in patients treated with temporary arterial occlusion during aneurysm surgery, we investigated postoperative neurological deficits relevant to the cerebral ischemia due to temporary occlusion and ischemic change on CT. There were 97 consecutive patients who underwent neck clipping with temporary occlusion under mild hypothermia (34ºC) anesthesia in the past 10 years at our hospital.
Ten patients (10%) had transient neurological deficits including mainly hemiparesis and 2 patients (2%) had permanent hemiplegia. Preoperative neurological state, such as an unruptured aneurysm, mild or severe subarachnoid hemorrhage, and patient's age did not correlate with the frequency of postoperative neurological deficits. More than 20 minutes of temporary occlusion increased the frequency of ischemic neurological signs after surgery. Permanent hemiplegia occurred with occlusion times between 19 and 28 minutes. Temporary occlusion of the middle cerebral artery tended to raise the frequency of postoperative neurological deficits. Small infarction of the perforating artery territory was revealed on CT scan in 17 percent of 12 patients who presented neurological dysfunction. Temporary arterial occlusion was mainly applied to reduce dome pressure of the aneurysm and make a proper clip placement in cases of large domes and multi-dimensional neck geometry in 35 patients with unruptured aneurysm at a mean occlusion time of 6.5 minutes. In 62 patients with ruptured aneurysm, temporary arterial occlusion was used to prevent intraoperative rupture as well at a mean time of 12.9 minutes.
Therefore, the option of mild hypothermia may be indicated for a complicated ruptured aneurysm surgery, which requires about 20 minutes of temporary arterial occlusion.

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Treatment indication for unruptured arteriovenous malformations (AVMs) of the brain was investigated based on long-term results of low-dose Gamma Knife (GK) surgery. Thirty-nine patients with unruptured AVMs treated with GK surgery were followed more than 7 years. These AVMs were found due to seizure and steal symptoms in 22 and 4 patients, respectively, and incidentally in 13. Embolization was performed in 6 patients before GK surgery. Total obliteration was obtained in 83.3% after initial treatment and 95.8% after additional treatment. Bleeding before total obliteration occurred in 2 patients and adverse effect on the internal capsule in 1. It is concluded that low-dose GK surgery is safe and effective for the treatment of unruptured AVMs, especially symptomatic AVMs in functional areas.

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Although a number of operative procedures have been already reported to prevent cosmetic and functional complications following fronto-temporal craniotomy, little has been analyzed concerning the limitation of mouth opening due to the atrophy, fibrosis and contracture of the temporal muscle. Our focus was placed on the changes and degrees of maximum postoperative mouth opening day by day following fronto-temporal craniotomy. We evaluated the efficacy of newly modified craniotomy (n=17) compared with the previous conventional one (n=14).
Our modified surgical strategy comprises: 1) tailored fascia and pericranium in Z-shaped fashion, 2) gentle manipulation of fascia, pericranium and muscle, and 3) ample humidification of fascia, pericranium and muscle wrapped with soaked saline gauze during operation. In this maneuver, the temporal muscle was firmly anchored to the fascia and pericranium in the original position. Postoperative limited mouth opening of the modified group was quickly (P<0.05) and fully resolved with statistical significance.

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We performed the CEA for 100 consecutive patients of asymptomatic carotid stenosis from May 1993 to December 2004. There were 81 men and 19 women (48-83 years old) with a mean age of 69. The high cervical lesion (distal end is higher than C2 vertebral body) was recognized in 14 patients and contralateral occlusion was seen in 12 pacients. Five patients were over 80 years old. Fifty-five patients had coronary heart disease, and 21 patients received coronary artery bypass. Another 21 patients had percutaneous coronary intervention before CEA. Of the 42 patients treated for coronary artery disease, 16 patients had no history of previous ischemic heart attack. The electroencephalogram and the flow of internal shunt were monitored during operation. Although perioperative morbidity was 2% and there was no mortality, transient complications were recognized. Two patients had transient hemiparesis; 8 had cranial nerve palsy; 1 had postoperative arteriovenous fistula; 1 had mild acute myocardial infarction; 2 had wound infections; and there were 4 hematomas (2 operations).
To minimize complications, preoperative examination of the coronary artery disease, meticulous operative procedures and prevention of hyperperfusion syndrome are important.

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This study was designed to clarify the various factors associated with the poor prognosis of the dorsal aneurysm of the internal carotid artery.
Three hundred sixty-five aneurysms diagnosed by angiography were registered from 171 institutes in Japan by questionnaire between January 2001 and December 2003. The average age at diagnosis was 53.8 years among 105 men and 233 women patients. Sixty-eight aneurysms were located in C1, 74 in C1-2 and 213 in C2. Three hundred thirty-nine aneurysms obtained Glasgow outcome score (GOS) of all 365 aneurysms were extracted and classified into group A (Good Recovery (GR), Moderate Disability (MD)) and group B (Severe Disability (SD), Vegetative State (VS), Dead (D)) for analysing various factors. Poor prognostic factors were assessed by single variate analysis.
Significant prognostic factors are rupture as onset (Odds ratio [OR] 9.9850), intraoperative bleeding (OR 6.3979), postoperative regrowth of the aneurysm (OR 5.8586), preoperative rebleeding (OR 5.1278), postoperative bleeding (OR 4.6397), Hunt-Kosnik grade greater than 3 (OR 4.5247), suspicion of dissecting aneurysm on angiogram (OR 3.5023), World Federation of Neurosurgical Societies (WFNS) grade greater than 3 (OR 3.2734), diagnosis as dissection in the operative field (OR 3.2296), thin aneurysm neck (OR 3.0252), thin aneurysm dome (OR 2.8794), temporary occlusion of the cervical carotid artery (OR 2.8667), and Fisher group greater than 3 (OR 2.3564). No significant differences were observed in the history, including hypertension, age, sex, size of an aneurysm dome and neck, presence of other aneurysms for the poor outcome. Observation therapy, i.e., no treatment, was correlated with poor outcome. Any perioperative bleedings strongly correlated with poor outcome.
We should pay more attention to patients with a regrowing, thin walled aneurysm than to those with a larger aneurysm. Since the conservative treatment does not result in the good outcome, we need to treat those patients in the early stage.

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Because a preoperative rebleeding is one of the most significant prognostic factors as described in the Part 1 report of the nationwide surveillance on the dorsal aneurysm of the internal carotid artery (ICDA), an early surgery for this hazardous aneurysm is naturally thought to be the first recommended treatment of choice. To clarify the rationality of early surgery for ruptured ICDA, 221 cases that suffered subarachnoid hemorrhage (SAH) out of 365 registered ICDA cases of a nationwide surveillance databank were studied. There were 148 cases that underwent acute surgery (Group A) within 7 days from the onset of SAH, and 57 cases that received delayed operation (Group D) after 8th day. No surgical intervention was done to the remaining 16 cases.
Overall surgical outcome of Group A (GR+MD: 60.1%, SD+V: 14.2%, D: 25.7%) was significantly worse (P<0.02) than that of Group D (GR+MD: 79.0%, SD+V: 17.5%, D: 3.5%), despite the fact that the distribution of neurological grades on admission in both Group A (Grade 1+2: 46.8%, Grade 3+4: 44.6%, Grade 5: 8.5%) and Group D (Grade 1+2: 63.6%, Grade 3+4: 29.6%, Grade 5: 6.8%) were not statistically different. Intraoperative bleeding (IOB) was more frequently encountered in Group A (43.2%) than in Group D (14.0%) with a significant difference (P<0.05). Almost half of IOB were the type of a rupture in which the parent arterial wall or neck per se was torn away both in Group A (56.3%) and in Group D (50.0%). But the outcome of those with neck-torn type IOB in Group A was much worse (GR+MD: 36.1%, SD+V: 25.0%, D: 38.9%) than those with that in Group D (GR+MD: 60.0%, SD+V: 40.0%, D: 0%) although no significant difference was present between the 2 groups.
In summary, the outcome of surgical treatment for ICDA at acute stage is significantly worse than that at late stage at the moment because of the extremely poor prognosis in cases with neck-torn type IOB during acute surgery. To overcome poor prognosis resulting from rebleeding at acute stage, further investigation with more cases must be conducted to clarify the recommendable early surgical method improve the outcome of acute surgery for ruptured ICDA.

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