Advances in the treatment of intracranial aneurysms over the last decade have focused on 1) novel surgical treatments or adjuncts to surgery and 2) alternative nonsurgical treatments. The goal of these recent developments is to reduce the morbidity associated with the treatment of aneurysms. New microsurgical techniques include the use of direct arterial occlusion (Hunterian ligation), intraoperative electrophysiological monitoring, frameless image-guided stereotaxis, and intraoperative angiograms. Endovascular therapy has evolved to provide a viable alternative in the treatment of some types of aneurysms, and in some cases, combined endovascular and microsurgical therapies are required for certain difficult to treat aneurysms. Hypothermia, both mild and deep cooling, has recently been used as a cerebroprotectant during cerebrovascular cases, particularly when temporary clipping of feeding vessels is performed. Each of these innovations has played a role in reducing the morbidity and mortality of aneurysm surgery, and will be reviewed in this article.

抄録全体を表示

To evaluate the efficacy of bypass surgery, we analyzed the clinical outcome and cerebral hemodynamics of patients treated with bypass surgery.
Over a 3-year period, 21 patients were defined by clinical and laboratory criteria as suffering from hemodynamic cerebral ischemia. All patients had one or more episodes of focal cerebral ischemia due to unilateral internal carotid or middle cerebral artery occlusion. Computerized tomography scans either were normal or showed evidence of watershed infarction. The baseline cerebral blood flow (CBF) and cerebral vasodilatory capacity (CVC) were studied using ¹³³Xe single-photon emission CT and acetazolamide test, and both were found to be significantly reduced in all patients. Based on these criteria, superficial temporal artery-middle cerebral artery anastomosis was performed. One patient suffered a postoperative stroke with complete recovery, resulting in a morbidity rate of 4.8%. Over a mean follow-up period of 20 months, no patient had another episode of cerebral ischemia. Follow-up studies of baseline CBF and CVC showed significant improvement of the latter while the former was essentially unchanged. In view of these findings, we conclude that bypass surgery constitutes appropriate therapy for patients with hemodynamic cerebral ischemia, defined using the strict selection criteria employed in this study.

抄録全体を表示

A small hemispherical bulging from the anterior wall of the internal carotid artery (ICA), which we call a blood blister-like aneurysm (BBA), is a treacherous lesion. Treatment of this lesion requires special tactics. We report the course of patients with this lesion treated by endovascular occlusion of the cervical ICA with or without bypass surgery.
We describe 3 patients with BBAs who presented with subarachnoid hemorrhage (SAH). In these patients, the initial angiogram soon after SAH showed only a small bulging from the anterior wall of the ICA. This bulge progressed to a saccular appearance within a few weeks. Two patients were treated conservatively, and underwent endovascular occlusion of the cervical ICA in the chronic stage, 1 with and the other without STA-MCA anastomosis. One patient underwent direct surgery on the aneurysm in the acute stage; clipping after wrapping with a strip of gauze was performed. Repeated angiogram showed growth of the aneurysm. Endovascular occlusion of the cervical ICA was subsequently performed. All 3 patients did well and returned to their previous life style.
Our experience with these lesions, as well as a review of the literature, suggests that direct clipping often causes laceration of the lesion, and wrapping or clipping after wrapping may fail to prevent growth of the aneurysm. Endovascular occlusion of the cervical ICA with or without bypass surgery, which is less risky than direct surgery, is still useful for this kind of lesion.

抄録全体を表示

In the dural arteriovenous malformations of the anterior fossa, the incidence of intracranial hemorrhage is high. We studied 4 patients with nonhemorrhagic dural arteriovenous malformations of the anterior cranial fossa.
There were 3 males and 1 female. Two patients presented with frontal headaches and 2 patients were diagnosed incidentally.
Angiograms revealed the dural arteriovenous malformations fed by the anterior ethmoidal, middle meningeal, superficial temporal and anterior cerebral arteries. The draining veins were pial veins of the frontal lobe into the superior sagittal sinus and cavernous sinus. In all patients, angiograms demonstrated neither venous aneurysm nor varix. Operations were performed successfully on 2 patients. We analyzed the clinical features and radiological findings in 17 repored cases and our 4 cases of the nonhemorrhagic dural arteriovenous malformations.
There were 17 males and 4 females ranging in age from 38 to 69 (mean age of 58.5).
Headache was the reason for presentation in 5 cases, ocular symptoms in 6, seizure in 1, and tinnitus in 1. Eight cases were diagnosed incidentally. Angiographically, 6 cases had venous aneurysms or varix. This frequency was extremly low compared with hemorrhagic dural arteriovenous malformations of the anterior fossa. These findings indicated that a patient with dural arteriovenous malformations associated with a venous aneurysm has an increased risk of hemorrhage.
Venous aneurysm should be treated aggressively.
With a venous aneurysm, aggressive treatment should be done.

抄録全体を表示

Aneurysms of the vertebral artery (VA), most of which originate at the junction of VA and the posterior inferior cerebellar artery (PICA), are usually surgically treated via a unilateral suboccipital (ULSO) approach.
The ULSO approach from the dorsal side and beyond the lower cranial nerve, is effective in cases with low-positioned or small aneurysms.
However, in cases with a large or higher-positioned aneurysm, the ULSO approach may cause postoperative retraction injury and/or lower cranial nerve palsy.
Several recent reports have suggested the advantage of transcandylar (TC) approach for those lesions. We analized surgical results of 10 cases with large aneurysms (>16mm) at the VA-PICA junction. Lower cranial nerves were found to be injured postoperatively in all 4 cases treated via the ULSO approach.
In contrast, postoperative permanent lower cranial nerve palsy appeared in only 1 of 6 cases treated with the TC approach.
Although aneurysms of the VA-PICA junction with moderate size and usual location can be sucessfully treated with the ULSO approach without any complication, the TC approach is indicated for large or high-positioned aneurysm.

抄録全体を表示

Infrared imaging has been developed for intraoperative assessment of regional hemodynamic changes during the surgical treatment of cerebral arteriovenous malformations (AVM's). The infrared images, obtained by a digital infrared camera installed on the operating microscope, demonstrated the hemodynamic status and changes of preoperatively embolized AVM nidus during the open surgery. The anatomical structures of AVM nidus and its surrounding tissues were easily observed as the difference of surface temperature on the operative field. The hemodynamic changes according to operative manipulations were immediately demonstrated as thermal change of the surface of the nidus and its components. Intraoperative infrared imaging is an easy and effective manner for intraoperative monitoring and real-time and noninvasive evaluation of the hemodynamic change during the AVM surgery.

抄録全体を表示

Purpose: We evaluated the efficacy and limitation of the intra-arterial local fibrinolytic therapy for acute thromboembolic stroke.
Method: After exclusion of intracranial hemorrhage by CT scan, patients with abrupt onset of focal ischemic symptoms underwent angiography within 7 hours after ictus. Patients with thromboembolisms received 24×10⁴ IU of urokinase or 10 megaunits of recombinant tissue plasminogen activator through a microcatheter placed into the occluded lesion for 20 minutes. When arterial recanalization was not achieved, a second or third infusion was performed. Recanalization efficacy was assessed at the end of fibrinolytic therapy and intracranial hemorrhage was assessed at 24 hours later. The results were compared with those of 54 patients treated with intracarotid (21 cases) or intravenous (33 cases) infusion of fibrinolytic agents.
Result: The rate of recanalization was 71%. Middle cerebral artery and basilar artery occlusion demonstrated a high rate of recanalization (80%and 94% respectively). However only 30%of patients with internal carotid artery occlusion showed recanalization. There was no difference between tissue plasminogen activator and urokinase in restoring blood flow. In the intracarotid infusion group (20×10⁴ IU of urokinase for 30 minutes), only 3 patients showed recanalization without favorable outcome. The incidence of good outcome was higher in the intra-arterial local infusion group. In the patients with middle cerebral artery occlusion, 48%of patients with local therapy had a good recovery, while 24%in intracarotid and 32%in intravenous group had a good recovery. In the patients with basilar artery occlusion, only the local infusion group had a good outcome (24%). The incidence of hemorrhagic event within 24 hours was 28%, and only 2%clinically deteriorated.
Conclusion: Although this study is relatively small and further evaluation is needed, intra-arterial local fibrinolytic therapy can be effective for acute thromboembolic stroke.

抄録全体を表示

It is important to prevent intraoperative aneurysm rupture in patients with ruptured cerebral aneurysms, because intraoperative bleeding can have catastrophic consequences. It is very useful for aneurysm surgeons trying to prevent this complication to know the incidence of intraoperative ruptures, the clinical grades and the location of aneurysms in which they occur and, when during operations intraoperative ruptures occur most frequently. We evaluated 905 of our patients with ruptured cerebral aneurysms and discussed the prevention of intraoperative rupture.
Intraoperative aneurysm rupture was noted in 117 cases (13%). That rate was significantly higher in cases with middel cerebral artery aneurysms, anterior communicating artery aneurysms and anterior cerebral artery aneurysms than in those with internal cerebral artery aneurysms and vertebrobasilar artery aneurysms. The incidence was significantly higher in cases undergoing surgery on Day 0 to 3 and 8 to 14 than on Day 4 to 7 and after Day 15. The intraoperative bleeding rate was also significantly higher in cases with Hunt and Kosnik Grade III to V than in those with I to II. The rate of intraoperative hemorrhage was significantly lower in cases enduring temporary occlusion to prevent intraoperative bleeding than in those without temporary clipping. Over 90%of the intraoperative rupture occurred at the timing of aneurysm dissection and application of clips.
Temporary clipping effectively prevents intraoperative bleeding. That should be followed by aneurysmal dissection with sharp microsurgical technique, when the intraoperative rupture may most likely occur due to the aneurysm tightly adhering to the surrounding tissues and its thinned and reddened wall. Especially, temporary clips should be used in clinical grade III to V patients with aneurysms in the anterior communicating artery, the distal anterior cerebral artery or the middle cerebral artery, who undergo surgery on Day 0 to 3 or Day 8 to 14.
To avoid aneurysm rupture when retracting the frontal lobe, methods to decrease the retractor pressure should be devised. And the brain spatula should be pulled in the proper direction according to the position of aneurysms, involving the direction of aneurysmal domes, the location of blebs, and these possible adherence to the surrounding tissue. As insufficient dissection of the neck causes bleeding in clip application, it should be remembered that the aneurysmal neck must be sufficiently dissected from the surrounding tissue with temporary clipping. A wrapping aneurysm clip should be applied for a blister-like aneurysm in the anterior wall of the internal cerebral artery.

抄録全体を表示

A 21-year-old man presented with several episodes of ischemic attack involving the right extremities and speech. The first left carotid arteriogram revealed an embolic occlusion of the anterior ascending branch of the middle cerebral artery, although the left cervical internal carotid artery (ICA) appeared intact. Even after medical treatment, his neurological symptoms continued to deteriorate. At the second angiography carried out immediately after an episode of right hemiplegia and an amourosis of the left eye about one month later, a tapering occlusion of the left ICA was demon-strated, which was compatible with the findings of carotid arterial dissection. Hypervolemia and induced hypertension were started, and an occipital artery-middle cerebral artery anastomosis was performed 2 weeks after the final episode. Thereafter, he has been free of symptoms except for a mild expressive aphasia. Control angiography 8 months postoperatively demonstrated a complete occlusion of the left cervical ICA while the left hemisphere was well perfused through the bypass. Spontaneous internal carotid arterial dissection has become increasingly recongnized as a cause of cerebral ischemia, primarily in young patients. Although the benign nautre of the disease may indicate the use of noninvasive diagnositc tools and anticoagulant therapy, intensive care and surgical treatment will be mandatory for patients with progressive neurological deterioration, which is refractory to medical treatment as shown in this report.

抄録全体を表示

Surgery for VA-PICA aneurysms located near the anterior midline of the brainstem is one of the most difficult kinds of surgery. We successfully clipped a right VA-PICA aneurysm located in the anterior midline of the medulla oblongata through the transcondylar approach. A 47-year-old female was admitted because of headache, nausea, vomiting and loss of consciousness. CT scan showed a subarachnoid hemorrhage. Vertebral angiography revealed a right VA-PICA aneurysm located in the anterior midline of the medulla oblongata and at almost the same level as the hypoglossal canal. Direct clipping was first tried through the transcondylar fossa approach, but the aneurysm could not be exposed because of the obstacle created by the 12th C. N. Then the approach was changed to the transcondylar approach and partial condylectomy and partial Cl hemi-laminectomy were added. The aneurysm was clearly exposed through the approach with retraction of the medulla oblongata. A clip was successfully applied through the space between the 12th C. N. and the vertebral artery. The postoperative course was uneventful, and the patients was discharged without any neurological deficits. We discuss surgical approaches to VA-PICA aneurysms located near the midline in consideration of the level of the aneurysm, which is superior or inferior to the hypoglossal canal and nerves. Then we clarify the difference between the applications of the transcondylar fossa approach and the transcondylar approach to such VA-PICA aneurysms.

抄録全体を表示

In the last six years the indications for performance of carotid endarterectomy have become standardized by the availability of level one evidence from cooperative trial data. Four randomized cooperative trials for asymptomatic carotid disease and three randomized cooperative trials of symptomatic carotid disease have been completed and published. Asymptomatic carotid disease with 60% or greater linear stenosis on angiography has been shown to be better treated with surgery than with medical therapy alone. For symptomatic patients, linear stenoses of 70% or greater in all patients have been shown to have a significant benefit with surgical treatment. Symptomatic moderate stenosis of <50% is best treated medically, but NASCET now shows that surgery is best for >50% symptomatic stenosis in healthy patients. All surgical recommendations are based on a morbidity/mortality rate of 3% or less for the individual surgeon. Areas remain which were not addressed directly by randomized trials, and for which only lesser levels of evidence are available. These include Hollenhorst plaque, complete occlusion, silent cerebral infarcts, emergency surgery for stroke, and“stump”syndromes. This review discusses the evidence for carotid surgery in these categories, as well as my personal technique for successful carotid reconstruction.

抄録全体を表示