Treatment for a small cerebral arteriovenous malformation (AVM) less than 3 cm in diameter is selected from the 3 options: gamma knife surgery (GKS), microsurgery or conservative treatment. To choose the optimal therapeutic modality, the authors examined a total of 613 patients with small AVM using clinical decision analysis. Expected utility after treatment was estimated from each therapeutic results, a patient's age and history of previous bleeding. The utility was assumed as 100 for without disability, 75 for with disability and 0 for dead. The expected utility after microsurgery was the highest in patients younger than 50 years without previous bleeding, or younger than 60 years with previous bleeding. GKS was optimal for a patient aged between 50 and 70 years with previous bleeding, or aged older than 60 years with previous bleeding. The clinical decision analysis provides us useful information for selecting a preferable treatment in the patients with a small AVM.

抄録全体を表示

We retrospectively analyzed the clinical courses and outcomes of cerebral arteriovenous malformations in 212 patients (3-79 years old) admitted to our institute between January 1987 and December 1999 to evaluate the reduction in bleeding risks and seizure outcome after surgical treatment for cerebral arteriovenous malformations.
Cerebral arteriovenous malformations were located in the cerebral hemisphere in 141, basal ganglia-thalamus in 19, cerebellum in 24, corpus callosum in 12, brainstem in 6, and others in 10 (Spetzler & Martin grade I 17, II 44, III 81, IV 56, V 11, VI 3). The initial presentation was hemorrhage in 119, seizure in 40, ischemia in 21, headache in 18, and asymptomatic in 14. The annual re-bleeding risk was 11.9% in 119 cases with hemorrhagic onset, and the annual bleeding risk was 3.2% in 93 cases with non-hemorrhagic onset. In 127 cases who suffered from hemorrhage, total extirpation was done in 97 and complete obliteration was achieved in 109 in combination with transarterial embolization or radiosurgery or both.
In 85 cases without hemorrhage, complete obliteration was obtained in 55 cases. Surgical morbidity and mortality were 5.9% and 0.7%, respectively. Recurrence of arteriovenous malformations after microsurgical extirpation occurred in 4 cases after angiographical cure, and the annual bleeding risk after angiographical cure was 0.14%. In 40 cases with seizure onset, hemorrhage occurred in 4 cases, progressive neurological deficits occurred in 4 cases, and repeated seizure occurred in 4 cases. Microsurgery was performed in 28 epileptic cases and 125 non-epileptic cases. In epileptic cases, seizure was improved in 26 cases and no aggravation of seizure was observed. In non-epileptic cases, 9 cases experienced de novo seizure attack within 2 years after microsurgery, and 4 cases suffered from seizure 2 or more years after microsurgery. In 153 operated cases, 141 were seizure free with or without medication 2 years after the operation.
Microsurgical resection of cerebral arteriovenous malformations not only effectively eliminates hemorrhagic risk from nidus but also improves seizure outcome.

抄録全体を表示

To clarify the best treatment maneuver for intracranial arteriovenous malformation (AVM), we examined and reviewed the therapeutic maneuver, clinical course and outcome of 90 patients with intracranial AVM.
In all 90 patients intracranial AVM was diagnosed by cerebral angiography. Their clinical symptoms were intracranial hemorrhage in 54 patients, convulsion in 20 patients, other symptoms in 6 patients and asymptomatic in 10 patients. Their clinical courses were checked from each clinical chart and at the latest clinical visit. The mean follow-up period was 3.6 years.
Eleven patients were conservatively managed without any surgery or radiosurgery. During the follow-up period (mean: 5.7 years), 3 patients presented with the 4 episodes of intracranial hemorrhage. The hemorrhage rate was 8.02%/patient/year. Nineteen patients were treated with radiosurgery. At 6 months after the radiosurgery, the AVMs were occluded completely in 10 patients, and 4 patients showed the decreased AVM volume to less than half of the original. However, 2 patients showed serious complications: development of multiform glioblastoma and middle cerebral artery (M1 segment) stenosis. Surgical extirpation was performed on 60 patients. Complete obliteration was confirmed on postoperative angiography in all patients. Patients with high-grade AVMs had a worse outcome than those with low-grade AVMs. Morbidity was seen in 4 patients, and mortality was seen in 5 patients. Small-size AVM, without deep venous drainage, and younger age were the factors for good surgical outcome for AVM.
AVMs should be treated considering their relatively high bleeding factors, radiosurgical risks and surgical risks. Surgical extirpation should be performed not only with skillful surgical technique but also with supplementary maneuvers such as preoperative embolization, intraoperative angiography, intraoperative ultrasound, functional mapping and hypothermia during perioperative period.

抄録全体を表示

The indications for radical surgery to treat unruptured cerebral aneurysms (uAN) remain unclear. Most investigations of evidence-based medicine have focused on prognostic factors such as the natural history, surgical outcome, risk-benefit analysis, and socioeconomic effects, and not on patient factors such as decision-making, anxiety, or satisfaction. This study undertook a survey of these factors in 172 patients who underwent radical surgery during the last 7 years, using a mail questionnaire sent to a third person.
The total response rate was 53.5%. Almost 90% of patients could understand the explanation of their condition including the presence of uAN and risk of bleeding, and the proposed treatment. About 70 percent of patients (70.9%) selected the type of treatment from among observation, clipping, or coiling, and 72.8% decided on the same day as the explanation. Patient decision-making was affected by anxiety about bleeding (49.3%) and recommendation by the attending physician (43.2%). The delay from the decision to the operation was 1 month or less in half of the patients, but more than 6 months in about 20%.
Sixty-nine patients with asymptomatic aneurysms found on brain examination were treated by clipping, and 10 with asymptomatic aneurysms by coil embolization. Eighty-one patients with aneurysms causing SAH or neurological symptoms were treated by clipping, and 12 with giant aneurysms underwent other surgery.
Visual analogue scale analysis found that 75% of all patients were satisfied, but 91.6% of patients who underwent coil embolization were highly satisfied. The most common factor causing dissatisfaction was anxiety during the delay from the explanation to the surgical treatment (44%). Almost half of the patients complained of several problems other than neurological symptoms such as the surgical wound.
This study indicates that patient decision-making was highly affected by the explanation of the physician, especially the recommendation for treatment and the sense of anxiety about the possibility of aneurysm rupture. Patient anxiety should be minimized by collecting better evidence about the natural history, surgical risk, and recurrence of uAN. The reaction of individual patients to the potential risks and possibilities of surgical intervention differed enormously, so a tailor-made approach to individuals to support patient decision-making should be formulated.

抄録全体を表示

We treated a series of 125 patients with unruptured intracranial aneurysms (UIAs) over a period of 6 years and 5 months (1995.12.1-2002.4.30). Ninety-seven patients were operated on, 1 was endovascularly embolized, and 27 were observed. Of the 97 patients who were operated on, 4 had postoperative ischemic complications; 2 had a new cerebral infarction, 1 experienced deterioration of the known infarction and 1 had delayed symptomatic vasospasm.
The etiologies of the new cerebral infarction were a subclinical pre-existing stenosis of the parent artery around the aneurysmal neck and stenosis of the parent artery induced by inappropriate neck clipping. Worsening of the known cerebral infarction was seen in a recent case of infarction that developed 2 months before surgery. Pathogeneses of the delayed symptomatic vasospasm after surgery for UIAs are unclear, but the important point is that symptomatic vasospasm does occur after surgery for UIAs.
These results suggest that asymptomatic stenotic lesions of the parent artery around the aneurysmal neck have a potential to become symptomatic postoperatively and cause cerebral infarction, that a recent infarction is a risk factor of postoperative ischemic complication as is already known and that a delayed spasm can occur even after uneventful surgery for UIAs.

抄録全体を表示

Ruptured intracranial infective aneurysms are well-known but relatively uncommon. During the past 7 years, we treated 7 cases of angiographically verified, ruptured infective aneurysms. They comprised 1.8% of all the ruptured intracranial aneurysms treated at our institution during the same period. The incidence of ruptured mycotic aneurysm among patients with active infective endocarditis was 13.0% (7 out of 54). Five patients presented with intracerebral hemorrhage, and 2 with pure acute subdural hematoma. Five aneurysms (71.4%) were located on the distal branch of the middle cerebral artery, and 2 (28.6%) on the distal branch of posterior cerebral artery. Four of the 7 aneurysms (57.1%) were located in the “watershed” area between middle and posterior cerebral arteries.
Two patients who presented with acute subdural hematoma were in a life-threatening condition and required emergency surgery; 1 patient showed rapid clinical deterioration due to repeated rebleeding from the aneurysm. Among the 5 patients who presented with intracerebral hemorrhage, 1 underwent evacuation of hematoma and excision of the aneurysms, 2 underwent conservative treatment with antibiotics, and the other 2 were too critically ill to be treated. The infective organism could be identified in 4 of the treated 5 cases; penicillin G was given in 4 patients and cefcapene in one. All 5 treated patients returned to normal life. Ruptured intracranial infective aneurysm should be excised as soon as possible because rebleeding from the aneurysm can cause rapid clinical deterioration.

抄録全体を表示

We describe a useful method to avoid injury to an optic nerve and an internal carotid artery during intradural bone resection in the paraclinoid region. A semicircular dural flap is turned with 2 threads over the anterior clinoid process. The flap is extended over the underlying structures with tapered spatulas to create a space for drilling the bone. The site for drilling was adequately exposed, and bone was drilled away smoothly without damaging the underlying artery and optic nerve in 18 patients with paraclinoid aneurysms.
Advantages of this “protective dural flap” method include wide exposure for drilling, protection of the underlying structures from the drill head and suction tubes, and availability of their intermittent inspection during bone resection.

抄録全体を表示

We evaluated the long-term follow-up angiographical status of aneurysms treated with Guglielmi detachable coils (GDCs). Between December 1997 and December 2001, 42 aneurysms were embolized using GDCs and followed up for long-term periods. The initial rates of occlusion were 100% (total occlusion: TO) for 17 aneurysms (40.5%), ≥90% (subtotal occlusion: STO) for 15 aneurysms (35.7%) and less than 90% (partial occlusion: PO) for 10 aneurysms (23.8%). No recurrence was observed in completely occluded aneurysms. Of the 25 aneurysms that were incompletely occluded initially, progressive thrombosis occurred in 18, 5 were stable, and remnant regrowth occurred in 2. There was a small but insignificant difference on mean volume embolization rate (VER) between the group of progressive thrombosis in PO (25.22±7.10%) and stable and remnant regrowth in PO (17.35±3.09%).
Because of the potential difficulty in predicting the angiographical outcome based only on VER, we introduced an Embolization Score (ES) to estimate the angiographical status in follow-up periods. This score is multifactorial, comprising the aneurysmal size (≥10 mm), neck shape (wide neck), direction of aneurysm (terminal type) and volume embolization rate (≤20%). ES is derived by adding 1 point assigned for each feature indicated in the parentheses. Less than 2 points on this score strongly suggests long-term stability after embolization. This score may be useful for predicting the outcome of aneurysms incompletely treated with GDCs.

抄録全体を表示

Recently, stenting for cervical internal carotid artery (ICA) stenoses has been performed not only in the high-risk patients of carotid endarterectomy (CEA) but also in patients amenable to CEA. We report clinical results of 96 patients of cervical ICA stenoses (99 lesions) and the effects of our recent method using the blocking balloon catheter system (BBCS) to prevent distal embolism. Stent placement was performed under local anesthesia via the percutaneous transfemoral route.
In 37 early patients (37 lesions), we used BBCS only during postdilatation (group A). In contrast, we used BBCS during predilatation as well as during postdilatation in 45 late patients with 47 lesions (group B). In 96 patients, the mean stenosis rate before stenting, 80.0%, markedly decreased to 7.7% after the procedure. At 30 days, the morbidity, neurological deficit and mortality rates were 4.2%, 1.0% and 1.0%, respectively. Two (2.4%) of 81 cases showed distal embolism when BBCS was used, while distal embolism occurred in 4 (27%) of 15 cases of stenting without BBCS. On diffuson-weighted MRI (DWI), hyperintense areas were detected in 7 (47%) of 15 lesions of group A and in 3 (19%) of 16 lesions of group B. Therefore, use of BBCS during predilatation as well as postdilatation (group B) reduced hyperintense areas on DWI further. Moreover, despite the more complex procedures, the use of BBCS during predilatation did not seem to increase morbidity, neurological deficits or mortality at 30 days.
To summarize, stenting with BBCS for cervical ICA stenosis is an effective treatment with low morbidity and mortality rates. Both predilatation and postdilatation using BBCS are useful techniques for reducing risk of distal embolism on DWI.

抄録全体を表示

With technical advancements, three-dimensional computed tomography (3D-CT) has been utilized frequently for cerebral aneurysms. Some investigators maintain that only 3D-CT is sufficient for preoperative examination in aneurysms, including ruptured aneurysms. We clarify the usefulness and limitations of three-dimensional digital angiography (3D-DA) for aneurysm surgery.
Forty-three saccular aneurysms were included. Forty cases were ruptured, and only 3 cases were unruptured. Three-dimensional reconstructed images were obtained in these cases.
3D-DA was very useful for precise detection of the aneurysm neck and determining the relationship between the aneurysm neck and branches. But the size of the aneurysm could not be shown exactly.
3D-DA is valuable for planning the surgical treatment for cerebral aneurysms.

抄録全体を表示

Complete prevention of bleeding and avoidance of complications are prerequisite in surgery for unruptured aneurysms. We report a difficult case with 2 internal carotid aneurysms at the anterior choroidal artery and at the carotid bifurcation. We stress the importance of preserving the perforating arteries and multiple-clip-adjustment.

抄録全体を表示