Hisashi Nagashima

Risks of surgery for patients with unruptured intracranial aneurysms

BACKGROUND With the widespread use of less invasive imaging tools, such as magnetic resonance angiography and computed tomographic angiography, unruptured cerebral aneurysms are found much more often than in the past. This retrospective study was undertaken to determine the risk factors for surgical intervention in a patient with an unruptured intracranial aneurysm. METHODS Over a 5-year period, 1,558 patients with intracranial aneurysms underwent surgery at our center. Of these, 310 patients (20%) with unruptured aneurysms were included in this study. RESULTS Out of 310 patients with unruptured aneurysms, 292 (95%) had a favorable outcome, and only one patient (0.3%) with a giant vertebral artery aneurysm died. Aneurysm size larger than 15 mm and location of the aneurysm in the posterior circulation were independent risk factors associated with less favorable outcomes. Patients with a single aneurysm had a better outcome than did patients with multiple aneurysms. CONCLUSION Our results support the contention that surgical treatment of unruptured intracranial aneurysms carries a low risk of morbidity and mortality and may improve the outcome in patients harboring cerebral aneurysms by preventing the devastating effects of subarachnoid hemorrhage. Aneurysm size, location, and number were risk predictors for surgical morbidity in patients with unruptured aneurysms.

Endovascular treatment of basilar trunk aneurysm associated with fenestration of the basilar artery

Abstract Basilar trunk saccular aneurysms associated with fenestration are infrequent, especially in the middle or distal portion of the basilar artery. Surgical treatment of the basilar trunk aneurysm is difficult, due to its anatomical environment and the complicated surgical exposure. A 46-year-old woman presenting with Hunt and Kosnik grade II subarachnoid hemorrhage was found to have a ruptured aneurysm arising at the proximal corner of the associated fenestration in the middle portion of the basilar artery. Because of surgical difficulties anticipated in approaching the aneurysm, it was decided to treat it with endovascular embolization utilizing the Guglielmi detachable coil; and complete occlusion of the aneurysm was obtained. The efficacy of endovascular treatment for the basilar trunk aneurysm with associated fenestration is discussed from anatomical and embryological points of view, and relevant literature is reviewed.

Transradial approach for selective cerebral angiography: technical note.

Abstract Selective cerebral angiography is currently being performed using transfemoral and transbrachial approaches. However, these techniques require patients to tolerate a prolonged focal compression and sometimes cause serious complications such as pulmonary embolism. The authors describe a technique of transradial approach as a safer selective cerebral angiography. Between July 1997 and November 1998, 70 patients underwent selective cerebral angiography with a transradial approach using a 4-F catheter. The collateral blood supply to the hand from the ulnar artery was confirmed using Allen’s test prior to the procedure. To prevent the mechanical spasm of the radial artery, an arterial introducer 20 cm long was used. The radial artery was successfully punctured and cannulated in all patients. Selective catheterization of the intended vessels was obtained In over 98% of the carotid angiography and over 95% of the vertebral angiography. No major vascular complications such as cerebral infarction, upper limb ischemia, significant local hematoma or pseudoaneurysm were experienced. The transradial approach is a less invasive and safer technique for selective cerebral angiography, and could be an alternative to transfemoral and transbrachial approaches. [Neurol Res 2000; 22: 605-608]

Endovascular therapy versus surgical clipping for basilar artery bifurcation aneurysm: retrospective analysis of 117 cases

OBJECTIVE The purpose of this study was to retrospectively evaluate and compare the feasibility, indication and limitations of two treatment options, clipping and coil embolization, for basilar artery (BA) bifurcation aneurysms. MATERIALS AND METHODS During the last 13 years, 117 patients with 117 BA bifurcation aneurysms were treated exclusively with direct surgery until February 1997, and with either direct surgery or coil embolization therapy since March 1997. Of them, 76 (65%) aneurysms were treated with direct clipping and 41 (35%) were treated with Guglielmi detachable coils (GDCs) embolization. The 76 surgically clipped aneurysms were analyzed on the basis of the pre-operative angiograms as to whether coil embolization would be feasible or not if each case had been attempted. The 41 embolized aneurysms, on the other hand, were analyzed as to whether clipping surgery would be feasible or not if it had been attempted. RESULTS In the total 117 aneurysms, complete coil obliteration was judged to be possible and simple in 61 (52%) aneurysms, possible with complex techniques (difficult) in 29 (25%) and impossible in 27 (23%). Whereas, complete obliteration with direct clipping was judged to be simple in 66 (57%) aneurysms, difficult in 38 (32%) and impossible in the remaining 13 (11%). Linear correlation as to the technical difficulty was found in 61 (52%) aneurysms, but 14 (12%) had marked discrepancy between the two methods. Of the 76 patients treated with clipping surgery, 17 (22%) were left with some post-operative neurological deficits, and in six out of the 17 aneurysms, embolization might have been simple. There were complications in two patients; one procedure-related and the other with late re-bleeding due to aneurysmal re-growth, in the embolization, group. CONCLUSIONS Endovascular therapy is an effective alternative for treating BA bifurcation aneurysms, although a quarter of the cases cannot be obliterated completely. It is important to select a suitable treatment option in each case depending on the patients condition and the angiographical features of each aneurysm as well as the characteristics of the two methods.

Giant aneurysms of the horizontal segment of the anterior cerebral artery: report of two cases.

Two cases of giant aneurysm of the horizontal segment of the anterior cerebral artery (A1) are presented. The rare occurrence of a giant aneurysm in this location necessitates evaluation of the cross-flow through the anterior communicating artery when planning surgical strategy. On the basis of angiographic findings, trapping of the A1 on both sides of the aneurysm neck was performed in Case 1, and aneurysmorrhaphy utilizing an angioplastic multiple-clipping method of A1 endarterectomy was accomplished in Case 2. The postoperative courses of both patients were satisfactory.

Subtle computed tomography abnormalities in cerebral deep sinus thrombosis.

A patient with cerebral deep sinus thrombosis, which was not diagnosed on the first examination, is reported. A 46-year-old woman presented with headache and vomiting. Neurological examination and a brain computed tomography (CT) scan showed no obvious abnormal findings. The patient suffered disturbed consciousness on the day after the examination, and was admitted to our emergency centre. A CT scan and magnetic resonance imaging revealed an ischaemic lesion in the left basal ganglia, suggesting deep sinus occlusion. Anticoagulant therapy was administered. One day after admission, a CT scan showed a haematoma and severe brain swelling in the same region. Cerebral angiography demonstrated a straight sinus occlusion. Intracranial pressure was not controlled with hypothermia, and the patient died 25 days after admission. Review of the initial CT scan revealed subtle, early findings of deep venous thrombosis that were missed on first examination.

Uncommon course for a vertebral artery dissection: Rupture, occlusion and recanalization

Intracranial arterial dissections of the vertebrobasilar system are recognized as a cause of stroke. Although the pathogenic mechanism underlying this phenomenon is unknown, in some cases the stroke originates from subarachnoid hemorrhage, while in others ischemia is the cause. In cases where hemorrhage occurs, occlusion of the lesion is effective in reducing the risk of re-bleeding. However, deciding on treatment is difficult in uncommon cases in which occlusion occurs immediately after hemorrhage. Intracranial arterial dissections of the vertebrobasilar system often present as subarachnoid hemorrhage, and the most appropriate surgical treatment remains controversial. In this report, we describe a rare case of vertebral artery dissection in which occlusion occurred immediately after subarachnoid hemorrhage. Serial angiography revealed spontaneous recanalization of the right vertebral artery dissection, as well as enlargement. The progressive angiographic changes of the ruptured vertebral artery dissection and the endovascular treatment of such arterial dissections are discussed.

Gross total surgical removal of malignant glioma from the medulla oblongata: report of two adult cases with reference to surgical anatomy.

Surgery was performed on the medulla oblongata of two adult patients with malignant glioma. Gross total resection of the tumors, located laterally or medially in the upper half of the medulla respectively, was achieved. The patient with the medially located tumor experienced significant postoperative neurological deterioration including sleep apnea. The other patient with the laterally located tumor showed symptomatic improvement without respiratory complications. The patient with an anaplastic astrocytoma survived approximately 4 years and the patient with a glioblastoma multiforme approximately 2 years. Although the upper half of the medulla is more critical than the lower half, a lateral approach to the upper half of the medulla appears to be relatively safer than a medial approach. Some cases of focal malignant gliomas in the medulla may be amenable to gross total resection in order to achieve improved outcome. Surgery can be undertaken when a tumor is unilateral and its margin appears relatively clear on magnetic resonance images.

Double aneurysms at distal basilar artery: report of nine cases.

OBJECTIVEDouble aneurysms at the basilar bifurcation and the basilar artery-superior cerebellar artery (BA-SCA) junction have not been well investigated previously. We analyzed nine patients with double basilar aneurysms to evaluate their radiological characteristics and suitable treatment. METHODSBetween 1978 and 1999, the incidence of double aneurysms was 5.3% in our 169 consecutive surgical cases of distal BA aneurysms. Seven (77.8%) of the nine patients with double aneurysms had associated aneurysms in the anterior circulation. Open surgery was performed in eight patients and coil embolization in one. The patients’ radiological findings, choice of treatment, and surgical results were analyzed retrospectively. RESULTSThe size of the basilar bifurcation aneurysms ranged from 2 to 8 mm (mean, 4.4 ± 2.0 mm), and the size of the BA-SCA aneurysms ranged from 2 to 12 mm (mean, 5.6 ± 3.6 mm). Diagnosis of double basilar aneurysms was difficult when the basilar trunk had twisted or when size differences between the two aneurysms were apparent. The angle between the posterior cerebral artery and SCA appeared to be wider on the same side as the BA-SCA aneurysms (101 ± 42 degrees) than on the opposite side (26 ± 24 degrees). The P1 segment of the posterior cerebral artery originated in an upright direction from the basilar bifurcation between the two basilar aneurysms in seven patients. The pterional approach was used in eight patients; 14 basilar aneurysms were successfully clipped and 2 were wrapped. Nonstraight clips with short blades were used frequently. Coil embolization of double aneurysms was required twice in one patient because the initial angiogram was misinterpreted as a single aneurysm and its bleb. CONCLUSIONMeasurement of the posterior cerebral artery-SCA angle is a simple method to estimate the presence of BA-SCA aneurysms and to differentiate double aneurysms from a bilocular aneurysm at the basilar bifurcation. The pterional approach is suitable for clipping double basilar aneurysms because anterior circulation aneurysms often coexist, and the upstanding P1 segment is an obstacle in the subtemporal approach to the basilar bifurcation aneurysm. Nonstraight clips with short blades are convenient to avoid conflicting clips in the narrow surgical space.

Total Resection of Torcular Herophili Hemangiopericytoma with Radial Artery Graft

A case of recurrent hemangiopericytoma involving the torcular herophili is reported, with special reference to the reconstruction of the straight sinus with a radial artery graft. In preoperative investigations, the tumor was found invading the straight and transverse sinuses. The involved occipital superior sagittal sinus had been removed in the previous surgery. A collateral bypass was observed from the superior sagittal sinus to the straight sinus, and the veins of Rosenthal were not opacified, suggesting poor venous drainage from the deep venous system to the cavernous sinus. We considered it necessary to reconstruct the straight and right transverse sinuses to achieve total removal of the tumor. The affected sinuses were removed and were successfully reconstructed with a radial artery interposition graft between the straight and right transverse sinus. The postoperative course was good, and the bypass was patent on the postoperative angiogram. The details of the operative technique are described.