A devastating complication after surgical clipping for intracranial aneurysms is neurological deficits caused by blood flow insufficiency of perforating arteries. To preserve blood flow of perforators, surgeons must identify all perforators around aneurysms. When a perforator adheres to aneurysmal walls, it should be dissected from the aneurysms as far as possible. When a perforator originates at an aneurysmal neck or dome, a clip must be placed with shaping the origin of the perforator. After clipping, the patency of perforators are confirmed by Doppler ultrasonography, indocyanine green (ICG) videoangiography and motor-evoked potential (MEP) monitoring. The above-mentioned meticulous surgical maneuver can minimize the risk of cerebral infarction due to the occlusion of perforators and improve surgical outcomes after aneurysmal clipping.

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Endovascular treatment has taken advantage of microsurgical clipping of the cerebral aneurysm since the advent of stent-assisted coiling. This is because several studies indicated that endovascular coil embolization had been associated with better outcomes than surgical clipping though coiling leads to a greater risk of rebleeding. Certainly, endovascular treatment has been a valuable therapeutic alternative for the cerebral aneurysm, though microsurgery still plays an important part in the treatment of cerebral aneurysm.
First, we discuss the apparent need for microsurgery to treat aneurysms in cases requiring revascularization to the distal of aneurysms, decompressive procedure due to intracranial hemorrhage, and to prevent repeated bleeding from the preciously coiled aneurysms. Moreover, microsurgery is relatively required to treat such cases as distal aneurysms, and aneurysms presented with mass effect. Second, we review the long-term follow-up outcomes of ruptured cerebral aneurysms treated at our hospital over 20 years between 1991 and 2011.

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A trans-cisternal approach, such as the anterior temporal and the anterior interhemispheric approach, is generally considered the standard and useful approach in surgery for a cerebral aneurysm. Although careful dissection of the perivascular arachnoid provides wide and safe operative fields in most cases, complications due to overdissection of the perivascular arachnoid have occurred in a few cases. We describe the problems and technical points of arachnoid dissection when using the trans-cisternal approach for cerebral aneurysms.

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In this study, we evaluated the embolic state based on imaging findings two years after embolization, and divided our patients into groups to examine postoperative changes in imaging findings.
We studied 61 patients with cerebral aneurysms who underwent embolization in our hospital. There were 23 males and 38 females (mean age 60.6 y) with 66 aneurysms (16 ruptured and 50 unruptured). Embolic state was evaluated two years after treatment, and subsequent imaging-based follow-up with MR angiography was continued for six months or more. The follow-up period ranged from 30 to 146 months after embolization (median: 49, mean: 63). Based on the embolic state two years after coil embolization, the aneurysms were divided into three groups: complete occlusion (C group), neck remnant (N group), and body filling (B group) groups. Changes in the embolic state at the final evaluation point were investigated.
Two years after embolization, 39 aneurysms were assigned to C group, 21 to N group, and six to B group. According to the final results, complete occlusion was noted in 37 aneurysms (94.8%) in C group, neck remnants in 18 (85.7%) in N group, and body filling in six (100%, additional treatment: 1) in B group; there were no changes in comparison with the results two years after embolization. We compared the results between ruptured and unruptured groups. In the former, there were no changes in 13 aneurysms, improvement was achieved in one, and deterioration was noted in two. In the latter, there were no changes in 47 aneurysms, improvement was achieved in two, and deterioration was noted in one (additional treatment: one aneurysm); there were no differences. With respect to the aneurysmal size, there were no differences in the results among three groups with a capacity of ＜100 mm³ (41 aneurysms), 100 to 200 mm³ (nine aneurysms), and ≧200 mm³ (nine aneurysms). With respect to the volume embolic ratio (VER), there were also no differences among three groups with a VER of ＜20% (14 aneurysms), 20 to 30% (25 aneurysms), and ≧30% (21 aneurysms).
There were no changes in imaging findings two years or more after the coil embolization of cerebral aneurysms. The long-term result was very favorable regardless of the presence or absence of rupture, aneurysmal capacity, and VER. However, long-term follow-up was possible in only a small number of patients in specific groups, consisting of body filling or ruptured aneurysms; a larger number of patients should be investigated in the future.

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Endoscopic surgery plays a significant role in the treatment of intracerebral hemorrhage. However, the amount of residual hematoma cannot be measured intraoperatively from the endoscopic view, and it is difficult to know the precise location of the endoscope within the hematoma cavity. Therefore, we attempted to develop real-time ultrasound-guided endoscopic surgery using a burr hole type probe.
From May 2011 to February 2013, 12 patients with hypertensive intracerebral hemorrhage underwent endoscopic removal of hematomas. Six patients had putaminal hemorrhage, and six patients had thalamic hemorrhage with intraventricular perforation. Real-time ultrasound-guidance was performed with a burr hole type probe, through a burr hole made in the temporal region, to observe the endoscopic operation from another burr hole in the frontal region. Endoscopic sheath insertion was also guided. During removal of the hematoma, the operator navigated adequately based upon the information of the location of the residual hematoma. Finally, the remaining cavity was irrigated by artificial cerebrospinal fluid and was observed as a low echoic space, which enabled obvious detection of the hematoma.
This method allowed both real-time navigation of the endoscope and real-time viewing of the residual hematoma, which thus minimized the brain damage due to the surgery. While the second burr hole for real-time guidance increased the number of wounds during surgery, it might decrease brain injury.

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Our treatment modalities and techniques for intracavernous large or giant internal carotid artery (ICA) aneurysms have been changed based on past clinical experience. We report clinical results and pitfalls of bypass surgery for intracavernous ICA aneurysms.
This study included unruptured symptomatic 37 intracavernous ICA aneurysms in 36 patients. Treatment methods were selected based on the anatomical features of the aneurysm and neurological/hemodynamic conditions during balloon test occlusion (BTO).
Eleven aneurysms were treated without bypass surgery. Low flow bypass (STA-MCA anastomosis) was performed for 18 aneurysms, and eight aneurysms were treated with high flow bypass. A saphenous vein graft was originally used for high flow bypass, but it was changed with a radial artery because of the problem of long-term patency. ICA occlusion was accomplished by ligation of the cervical ICA alone in the early cases until we encountered a case with brain infarction due to emboli from the aneurysm after ICA ligation. Accordingly, ICA occlusion was performed by endovascular internal trapping two days after bypass surgery. There was, however, a case of graft thrombosis before ICA occlusion. We now occlude ICA by surgical trapping between the neck and the intracranial ICA immediately after revascularization. No patients had permanent ischemic neurological deficits due to cerebral hypoperfusion after ICA occlusion.
Our treatment algorithm based on BTO was reliable. When the patients undergo bypass surgery, we perform ICA occlusion by surgical trapping between the neck and the intracranial portion.

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In this study, we retrospectively investigated clinical features, radiological follow-up results, and outcome of patients with vertebral artery dissection (VAD) presenting with isolated head-nuchal pain. During the past 5.5 years, we experienced 69 VAD cases diagnosed either by MRI, 3D-CT angiography, or digital subtraction angiography. Among them, 41 patients (59%) who initially presented with only head-nuchal pain and showed neither subarachnoid hemorrhage (SAH) nor cerebral infarction were studied. The age of the patients (27 males, 14 females) ranged from 32 to 83 (mean 43) years. Once VAD was diagnosed, the patients underwent strict blood pressure control (systolic blood pressure ＜120 mmHg) and bed rest. In all cases, serial follow-up MRI examinations were performed for one week to five years after the onset. The radiological findings of VAD were classified into three types: fusiform dilatation (FD), narrowing or occlusion (N/O), pearl and string sign (PSS). As a past clinical history, hypertension was observed in 24 cases, smoking in 14 cases. Moderately severe and persistent occipito-cervical pain (71%) as well as unilateral pain ipsilateral to the affected VA (73%) were characteristics of VAD. The latency of the pain of the patients whose follow-up MRI images were improved or unchanged (mean six days) was significantly shorter than that of the patients whose images were observed aggravate (mean 11 days) (p＜0.03). The initial radiological findings of VAD were FD in 20, N/O in 11, PSS in 10. In all cases, fusiform dilatation of the vascular outer contour of the VA was observed on basiparallel anatomic scanning. Serial MRI showed radiological improvement in 26 cases and deterioration in eight cases. Among the eight patients with deteriorated in MRI images, two underwent endovascular coil embolization. No patients experienced SAH or neurological deficits during follow-up.
In patients with persistent unilateral occipito-cervical pain, the possibility of VAD should be considered. In addition, careful observation with a focus on blood pressure control might be required for the patients with unruptured VAD.

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The outcome of over 80-year-old (high-aged) subarachnoid hemorrhage (SAH) cases is poor. We report treatment strategy of those cases for independent daily life.
From 2005 through 2012, 41 high-aged aneurysmal SAH cases were treated (M/F＝3/38). During the same period, 327 SAH cases of aged under 80 were treated (young-aged). We compared the clinical characteristics of those two groups and researched the factors that correlated with favorable outcome at 30 days after the SAH. An X-square test was done for statistical analysis.
The ratio of female, conservative therapy, symptomatic vasospasm and poor outcome was significantly higher in high-aged group than in the young-aged group. In the high-aged group, the median age was 84 (range 80–90) and pre-stroke good modified Rankin Scale (0–1) was 89%. Clipping was done in 14 cases, coiling was done in nine cases and conservative therapy was done in 18 cases (44%). The reasons of conservative therapy were age (nine cases), poor Hunt-Hess (HH) grade (four cases) and other organ disease (three cases). Symptomatic vasospasm occurred in 18 cases. Favorable outcomes in the high-aged group were realized in 14 cases (34%). Factors that significantly correlate with favorable outcome were HH grade, surgical treatment and catheter intervention of symptomatic vasospasm. Age, pre-stroke modified Rankin Scale and symptomatic vasospasm were not related with outcome. Two cases achieved non-demential state.
In high-aged SAH cases with an HH grade of less than three, radical operation and strict post-operative management lead to favorable outcome. Avoidance of dementia is a problem that remains to be solved.

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We evaluated the usefulness of intra-arterial fluorescence cerebral angiography (FCAG) from a catheter inserted into the external carotid artery (ECA) via the superficial temporal artery (STA) for detecting the blood flow in the small arteries, capillaries and small veins in the brain surface during neurological surgery. After indocyanine green (ICG) or fluorescein sodium (Fluorescein) was injected into the STA, fluorescein reached the intracranial internal carotid artery (ICA) through the common carotid artery or anastomoses between the ECA and ICA. Fluorescence in the vessels of brain surface was observed through a microscope and recorded on DVD image.
In large arteries such as internal cerebral artery, images by FCAG using ICG were clearer than these by fluorescein-FCAG. On the other hand, in small arteries, capillaries and small veins in the brain surface, fluorescein-FCAG was superior to ICG-FCAG in resolution.
Intra-arterial fluorescein-FCAG is very promising for estimation of the blood flow in the brain surface because it allows confirmation of delay and stagnation of capillary arterial blood flow on the brain surface. Based on our findings, we suggest that observation of the blood flow on the brain surface by fluorescein-FCAG is useful to prevent unexpected cerebral infarctions and to improve the surgical outcome.

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It is important that we preserve intracranial veins as much as possible in peforming surgical clipping for unruptured aneurysms. Even so, we sometimes have to disconnect the veins to expose the surgical field. We report the usefullness of comprehending venous patterns as preoperative microsurgical information by arteriovenous phase of 3D-DSA.
Between July 2012 and July 2013, nine patients with 10 unruptured anterior circulation aneurysms were clipped in our hospital. The patients comprised two men and seven women, with a mean age of 63.3 years (range, 43–71 years). The aneurysms included four MCA aneurysms, three IC-Pcom aneurysms, two IC-bifurcation aneurysms, and one IC-Ach aneurysm. Cerebral angiography system in our hospital was Allura Xper FD 20. In arteriovenous 3D-DSA, we set injection rate 3 ml/sec, total amount 21 ml of contrast media, X-ray delay time 6.5 seconds, and exposure time 4.1 seconds. In all cases, important veins for surgery and vein adjacent to aneurysm were depicted by arteriovenous 3D-DSA.

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The patient was a 48-year-old male with an unruptured cerebral aneurysm located at the bifurcation between the right internal carotid artery and the persistent primitive trigeminal artery (PPTA). The patient underwent a coil embolization treatment because the aneurysm had a gradual growth on annual follow-up of magnetic resonance angiography. Balloon-assisted coiling of the aneurysm including PPTA was performed and complete obliteration of the aneurysm and the origin of PPTA was achieved. No complication related to the treatment was observed. On the follow-up angiography performed 14 months after the treatment, complete obliteration of the aneurysm was unchanged, but the antegrade flow of the PPTA was recovered.
PPTA is the most major persistence of fetal carotid-basilar anastomosis. Treatment and follow-up reports of aneurysms located at PPTA are still limited in number. In the discussion section, we summarize the previous reports and compare them to our case.

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