To assess the usefulness of surgery in patients with unruptured cerebral aneurysms to prevent subarachnoid hemorrhage (SAH), we analyzed surgical complications, long-term follow-up results of surgery, and occurrence of SAH in unoperated patients.
In the past 8 years (1992-1999), we found 271 patients with unruptured cerebral aneurysms. Excluding patients who had undergone clipping surgery for the unruptured aneurysms together with ruptured aneurysm at one time, we investigated 105 operated patients and 92 unoperated patients. The mean size of the aneurysm was 7.1 mm for operated patients, and 6.2 mm for the unoperated patients. Among unoperated patients, 6 had a SAH and 5 died. Two other patients died unexpectedly. One patient died due to mass effect of the aneurysm. Patients with aneurysms smaller than 5 mm did not have a SAH. However, the annual rupture rate for patients with aneurysms of 5-15 mm was 9.4%/year.
Surgical results were favorable. There was no mortality for patients with an aneurysm smaller than 5 mm. Surgical morbidity for this group was 2.4%. The operative risk for patients with aneurysms larger than 5 mm was higher. Mortality and morbidity after surgical treatment of patients with aneurysms between 5-15 mm were 1.8% and 5.5%, respectively. Only 1 patient had a SAH after surgery for the unruptured cerebral aneurysm. The operative risk for patients with aneurysms over 15 mm was 37.5%.
These results suggest that surgical treatment is necessary for patients with aneurysms of 5-15 mm. While it may be better to observe patients with aneurysms smaller than 5 mm, further investigation of the natural course of unruptured cerebral aneurysms in relation not only to aneurysm size but also to other factors such as aneurysm shape, hypertension, and history of SAH is necessary. For large aneurysms (<15 mm), careful assessment of the benefits of surgery is needed because of the high operative risk.

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We report the current strategy for unruptured intracranial aneurysms, the rupture rate and characteristics of previously unruptured aneurysms in Japan.
The information on the unruptured aneurysms was obtained from 14 institutes with the approval of investigators, and 1,602 cases were enrolled in this study. The condition leading to the diagnosis was a history of SAH (10%), other intracranial lesions (29%), symptomatic aneurysms (6%) and brain examinations (46%).
The surgical intervention for unruptured intracranial aneurysms in each institute was indicated for patients who were healthy and under 70-75 years old with aneurysms 3-5 mm or more in size, and 1,012 cases (63.2%) were operated. As for surgical options, 89.2% had open surgery and 11.7% endovascular treatment. Endovascular treatment was intentionally selected for those with juxta-dural ring IC or posterior circulation aneurysms. The morbidity and mortality in open surgery were 6.9% and 0.2%, respectively, and those in endovascular treatment were 2.5% and 0%, respectively.
Because of rejection of operation, elderly age, poor general condition, small aneurysm or operative risk 590 patients were observed. The mean observation period was 32.6 months, and during a 1,601 person-year follow-up study there were 45 episodes of hemorrhage from a previously unruptured aneurysm, giving an average annual rupture rate of 2.8%. They were 16 males and 27 females, and their mean age was 67.6. The size of aneurysm was 10.9±6.9 mm, but there were seven aneurysms less than 5 mm. There were 12 C1-2, 11 MCA, 10 Acom, 7 Basilar tip and 5 other aneurysms. Concerning outcome, 11 (24%) had a good recovery, 1 (2%) was moderately disabled, 1 (2%) severely disabled and 32 (72%) died. In contrast to this poor outcome, a good outcome was observed in 4 out of 5 cases under 70 years old whose aneurysms were found by means of brain examination and were smaller than 10 mm in size.
In conclusion, two-thirds of unruptured intracranial aneurysms were treated by open or endovascular surgery, and the results were satisfactory. One-third of those were observed at their own request or because of their condition, and the incidence of rupture was 2.8%/year. Among the elderly patients, the outcome was poor, but relatively good in younger patients and those with small aneurysms.

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Intravascular treatment has recently been introduced in the treatment of asymptomatic unruptured cerebral aneurysms (AUCAs). On the other hand, ploblems of how to treat AUCAs have been left unresolved. Our management of AUCAs is as follows: the first choice is surgery, the second is intravascular treatment and the third is conservative treatment. Our indications of surgery for AUCAs are as follows: 1) age: under 75, 2) location: anterior circulation, and 3) size: over approximately 5 mm in diameter. Clinical features of patients with AUCAs were investigated. Between 1995 and 1998, we experienced 148 patients who harbored 193 AUCAs. The aneurysms with other diseases of central nervous systems, multiple aneurysms co-incidentally found with ruptured ones, carotid cavernous aneurysm and non-succular type of aneurysms were excluded. Fifty-one were male, and 97 were female. Ages ranged from 39 to 87 years (mean: 59 years). Surgery was done in 77 cases (52%), intravascular treatment in 43 (22%) and conservative treatment in 39 (26%). Therapeutic results of surgery were 3% permanent morbidity and no mortality. Intravascular treatment resulted in no permanent morbidity and no mortality. Long-term follow-up revealed no aneurysmal rupture in the intravascular treatment group. In the conservative treatment group, aneurysmal rupture was found in 3 cases (annual rupture rate was 3.1%). Those aneurysms were clipped successfully, but 1 patient died of acute heart failure 1 year later. Our management strategy provides satisfactory therapeutic results in patients with AUCAs. It is important to select the best treatment among the three treatments for AUCAs: surgery, intravascular treatment and conservative treatment.

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We describe 4 patients with spontaneous dissecting aneurysm of the intracranial vertebral artery, which presented with headache and neck pain as the only manifestation. The onset of headache and neck pain was gradual in all patients. Pains were distributed to the unilateral posterior head and neck region and were pulsating in 2 patients (50%) and steady in 2 patients (50%) and lasted for several minutes to several hours. The pains sometimes waxed and waned. The pains of the same kind appeared repeatedly. MRA was useful for detecting the vertebral artery abnormalities, such as string sign and aneurysmal dilatation. One patient was treated surgically because of refractory pain. The other patients were treated nonsurgically, i.e. bed rest and pain control. Follow-up MRA demonstrated healing of the dissection.

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Forty-five patients underwent surgery for unruptured cerebral aneurysm.
Postoperative brain damage occurred in 3 cases (6.7%). The possible causes of the damage were venous infarction. One patient died due to pneumonia induced by bilateral recurrent nerve palsy. Two other patients developed transient neurological deficits. One venous infarction was induced by the combination of postoperative meningitis and minor injury of the vein during surgery. This patient recovered by external decompression surgery and barbital coma therapy.
A careful preoperative assessment and intraoperative management of cerebral vein adhesive to cerebral aneurysm is indispensable.

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The natural history of intracranial arterial dissection is not well known yet, so that adequate treatment is still controversial for this disease. We conducted this study to elucidate the clinical features and the long-term outcome of the conservatively managed patients with the intracranial arterial dissection and subarachnoid hemorrhage in the vertebrobasilar system.
Twenty-five patients were conservatively managed (only control of high blood pressure, no antiplatelet nor anticoagulant), whereas 64 underwent surgery, including intravascular surgery. The reasons for the conservative treatment were: anatomical problems in 11, poor clinical state in 9, and treatment strategy in 5.
In the retrospective analysis, age, clinical severity, location of the dissection, and angiographical findings did not differ between the 2 groups. The incidence of the history of arterial hypertension and the rate of rebleeding were significantly higher in the conservative group.
In the conservative group, the follow-up period ranged from 0.5 to 14 years (mean=6.4 years). The most common finding on serial angiogram was no change on the initial one, followed by improvement. As for outcome, 13 patients died of rebleeding or vasospasm in the acute stage. The long-term outcome in the remaining 12 was favorable: Eleven made good recovery.
These results suggest that the long-term outcome in the ruptured vertebrobasilar arterial dissection might be favorable, if the patients overcome the various problems in the acute stage.

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Twelve (43%) out of a total of 28 patients with middle cerebral artery aneurysms had reddish thinning in the parent artery close to aneurysmal neck. The conventional technique of aneurysmal neck clipping with the clip blades parallel to the parent vessel usually does not take care of this weak point, which is liable to rupture. In this study, we describe a technique of wrapping of this weak spot simultaneously with the clipping of the aneurysmal neck. At first, a sheet of Bemsheet (non-fabric cotton) is wrapped around the M2 origin to cover the weak point. Then the aneurysmal neck is clipped over the Bemsheet. This procedure provides a tight reinforcement without leaving any space between the arterial wall and Bemsheet, in contrast to wrapping after neck clipping, which can only form a loose reinforcement. Plastic adhesives were not used in order to avoid the possibility of delayed narrowing of the parent artery. This procedure may also be useful in a case of aneurysm with a red neck, where Bemsheet plays the role of a cushion and lessens the possibility of neck avulsion during clipping.

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Cerebral aneurysms of the proximal middle cerebral artery (M1) are a relatively rare condition. We report 14 cases of such aneurysms that were treated by direct surgery. There were 9 men and 5 women. Ages ranged from 5 to 70 years old (average of 50). Ten aneurysms were unruptured and 4 were ruptured. The size of the aneurysms ranged from 2 mm to 13 mm (average of 6 mm). Ten aneurysms arose from the superior wall, 3 from the inferior wall and 1 from the posterior wall of the M1 segment. The aneurysms were exposed through the pterional craniotomy and transsylvian approach. Neck clipping was accomplished successfully in 13 cases using straight or bayonet-shaped clips. A dissecting aneurysm arising from the posterior wall was clipped with a right-angle ring clip. Careful dissection of the lenticulostriate arteries from the aneurysm is important to prevent ischemic complications, especially in aneurysms arising from the superior wall.

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We retrospectively analyzed and compared overall outcome of poor-grade patients (WFNS Grade IV, V, and cardiopulmonary arrest on arrival |CPAOA|) with subarachnoid hemorrhage (SAH) in 2 study periods. The first was from July 1993 to June 1994 and the second from July 1998 to June 1999. A total of 20 patients, 7 with Grade IV, 5 with Grade V, and 8 with CPAOA were included in the first period; and a total of 36 patients, 6 with Grade IV, 21 with Grade V, and 9 with CPAOA, in the second period. The major recent changes in the treatment protocol were 1) deep sedation, intensive control of blood pressure, and endotracheal intubation in the emergency room in the resuscitative phase; 2) immediate cerebral angiography under general anesthesia after diagnosis of SAH; 3) aneurysm obliteration by Guglielmi detachable coil (GDC) as an option; and 4) early enteric feeding and tracheostomy for patients in a prolonged comatose state. Therapeutic mild brain hypothermia was conducted in 3 Grade V patients in the second-period study. Aneurysm was obliterated by clipping in 7 and 18 patients in each period and by GDC in 4 patients in the second period. The median time from onset to admission, to angiography, and to surgery was 29, 440, and 797.5 minutes, respectively, in the first period, and 32, 99, and 210 minutes, respectively, in the second period. Overall outcome assessed at 3 months by the Glasgow Outcome Scale was; GR: 2 (10%), MD: 0 (0%), SD: 1 (5%), VS: 2 (10%), D: 15 (75%) for the first period and GR: 5 (13.9%), MD: 3 (8.3%), SD: 7 (19.4%), VS: 1 (2.8%), D: 20 (55.6%) for the second period. A favorable outcome (GR+MD) increased from 10% to 22.2%, and deaths were reduced from 75% to 55.6% (P=0.02, chi-square test). Angiography and surgical intervention immediately after resuscitation produce a more favorable outcome for severe SAH patients without increasing the risk of rerupture.

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In recent large randomized trials performed in North America and Europe, the beneficial effects and guidelines of carotid endarterectomy (CEA) have been reconfirmed for symptomatic and asymptomatic patients with high-grade carotid artery stenosis. These studies also demonstrate that successful results of CEA dependen upon surgeons having minimum perioperative morbidity and mortality rates. Wound hematoma is the most basic technical complication, and the incidence rates in the literature ranges from 1.9 to 4.3%. Especially, arterial bleeding from the suture line or the disrupted wall is fatal, and higher occurrence has been reported in the case of inexperienced surgeons.
Each process of CEA, including arterial preparation, removal of atheroma plaque and suture of arteriotomy requires the ability to perform surgical procedures with minimum complications. Meticulous surgical technique in obtaining hemostasis and control of postoperative hypertension will help reduce the incidence of postoperative wound hematoma. Based on our clinical experiences of 215 cases, we present our ideas and technique of CEA to prevent wound hematoma. We also review the recent clinical data and discuss the existing state and problems of this clinical category of CEA in Japan.

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