Treatment for recurrent intracranial aneurysms previously treated with endovascular coiling remains challenging, and an optimal strategy remains to be established. Nine recurrent cases of previously coiled aneurysms were treated with surgical clipping at our institution. Based on the preoperative digital subtraction angiography finding, the remnant volume (V_remnant) and coil mass volume (V_coil) of each recurrent aneurysm were calculated to assess aneurysmal collapsibility. Three aneurysms were clipped on the coil mass, and the remaining 6 aneurysms were clipped below the aneurysmal neck. All 9 aneurysms were surgically treated with standard clipping. The mean (95% confidence interval) V_coil/V_remnant ratio was 0.27 (0.18-0.36), suggesting that the aneurysms with <36% of the coil mass volume relative to the remnant volume were safely clipped. Clipping is still an important treatment option for recurrent coiled aneurysms if the patients are younger or found unsuitable for the endovascular approach, although preoperative angiographic examination regarding aneurysmal collapsibility should be evaluated.

Confirmation of complete clipping using indocyanine green (ICG) videoangiography after neck clipping for cerebral aneurysms is a standard procedure. We sometimes experienced delayed, pulsatile ICG inflow around the neck after clipping. However, due to this incomplete clipping, clipping is repeatedly attempted or multiple additional clips are used in comparison with the size of the aneurysms, until ICG does not flow into the aneurysms. For unruptured aneurysms, we have not dared to attempt such unreasonable additional clipping, assuming that the aneurysms would be thrombosed by stagnant blood flow. The purpose of the present study was to investigate the mechanism of delayed, pulsatile ICG inflow around the neck and verify aneurysm curability. Among 276 unruptured cerebral aneurysms treated with neck clipping between January 2008 and August 2017, 10 that showed this phenomenon after neck clipping were evaluated. Three-dimensional CT angiography after neck clipping revealed a disappearance of the aneurysms in all the cases. No recurrence of the aneurysms was observed over 38 months of follow-up. Disappearance of the aneurysms led to the conclusion that such an ICG phenomenon induces thrombosis of the aneurysms, resulting in complete obliteration of the aneurysms. However, given the small number of cases and short observation period, more cases are needed in the future, with extended follow-up and an evaluation of safety.

Background and purpose: Endovascular coil embolization is an acceptable first-line treatment modality for ruptured anterior communicating artery (AcoA) aneurysms. The management varies among institutions because the causes for selection of coil embolization include not only aneurysm morphology but also institutional factors. We assess our experience with a “coil first” policy and determine predictors of complications. In addition, we report our institutional factors.

Materials and methods: We retrospectively analyzed 27 consecutive patients with a ruptured AcoA aneurysm who underwent coil embolization at our institution between August 2013 and July 2016. During this period, none of the patients had a crossover to clipping. More than half of the neurosurgeons at our institution had much more experience with coils than with clips.

Results: Of the patients, 11 were women (40.7%). The mean age of the patients was 58.0 years. The overall clinical outcome was modified Rankin scale (mRS) score of 0-2 in 16 patients (59.3%), 3 or 4 in 4 (14.8%), and 5 or 6 in 7 (25.9%). Intraprocedural rupture (IPR) occurred in 4 patients whose aspect ratios (ARs) were <1.5. Of the 4 patients, 1 had a small basal outpouching (SBO) associated with IPR. Delayed rebleeding occurred 3 years after the initial coil embolization. Three patients underwent additional treatment without procedure-related complications. One of the recurrent aneurysms with a SBO was treated with clipping in the chronic stage.

Conclusion: As worse outcomes are associated with IPR and delayed rebleeding, crossover to clipping in the case of AR of <1.5 or SBO may allow a safer obliteration in the acute stage. Intentional partial coil embolization followed with additional clipping in the chronic stage, however, may improve procedural safety.

The purpose of this study was to determine an optimal treatment strategy between coil embolization and non-surgical treatment for unruptured cerebral aneurysm from a cost-effectiveness point of view. With a Markov model and Monte-Carlo simulation, we compared coil embolization with non-surgical treatment in patients with an unruptured cerebral aneurysm. We varied the patient age range between 50 and 85 years with an interval of 5 years. We also varied the rupture rate of aneurysm between 0.5% and 3.5% per year with an interval of 0.5%. A simulation cycle was repeated until 99.9% of the patients changed to a dead status. To analyze the impact on costs and quality-adjusted life-year (QALY), a threshold of incremental cost-effectiveness ratio (ICER) was set to 5,000,000 yen and 3,000,000 yen, respectively, representing the standard criteria of Japan and United Kingdom. With an estimated aneurysmal rupture rate of 1.0%, 1.5%, and 2.0% per year, coil embolization was more cost-effective in male patients under 68, 74, and 78 years age and female patients under 71, 77, and 81 years of age, respectively. Assuming that the utility health value of non-surgical patients with a rupture rate of 1.0% per year decreases from 1 to 0.95, coil embolization was more cost-effective in male patients under 79 years and in female patients under 81 years.

The occipital artery-posterior inferior cerebellar artery (OA-PICA) bypass is a well-known surgical technique for the treatment of vertebral artery (VA) aneurysms involving the PICA. However, the OA-PICA bypass is considered to be a difficult procedure owing to the deep operative field and the proximity of the lower cranial nerves. The mid-lateral suboccipital approach allows for the establishment of a wide and superficial operative field reliably and safely.

We performed OA-PICA bypasses for five cases that included dissecting VA aneurysms (two cases), a large VA aneurysm (one case), a PICA dissecting aneurysm (one case), and a VA-PICA aneurysm (one case).

The patients were placed in the prone position. J-shaped skin incisions were made, and osteoplastic craniotomies were advanced to the condyle fossa, which provided wide and superficial operative views. Trapping/clipping and OA-PICA bypass were performed in all the five cases. The most critical step in the bypass was the intimal check before pulling out the needle.

In our technique, the wide and superficial operative field enabled us to safely perform the clipping and OA-PICA bypass.

We reviewed eight patients presenting with brainstem cavernous angiomas for whom microsurgical approaches were employed. The lesions were located in the dorsal midbrain in two patients, dorsal pons in two patients, ventral pons in three patients, and dorsal medulla oblongata in one patient. Microsurgical resection was performed via the occipital transtentorial approach for the dorsal midbrain lesions, the telovelar approach for the dorsal pons and medulla oblongata lesions, and the posterior transpetrosal approach for the ventral pontine lesions. Post-operative neurological status was either unchanged or improved in all cases. Establishment of the surgical corridor and a wide viewing angle for the lesion is an essential strategy to safely excise the brainstem cavernous angiomas with functional preservation of the surrounding vital neural structures.

Carotid endarterectomy (CEA) is a standard surgical procedure used to treat carotid artery stenosis and the associated peri-procedural stroke rate is lower than that associated with carotid artery stenting (CAS). However, the latter is preferred as it is comparatively less invasive. We compared the efficacy of CEA for symptomatic stenosis and CAS for asymptomatic or transient ischemic attack, while considering other factors such as anatomy, renal function, and general status before selecting the final procedure. We operated on 5 lesions using CEA and 14 lesions using CAS. One patient with symptomatic stenosis who was treated using CEA developed symptomatic postoperative stroke. Symptomatic stenosis, vulnerable plaque, and hazardous anastomosis were associated with an increased risk of stenting. A higher location of internal carotid artery stenosis and other anatomical factors should be considered before selecting endarterectomy.

Ischemic symptoms of the anterior cerebral artery (ACA) are rarely concomitant with internal carotid artery (ICA) occlusion. When the A1 segment of the ACA is hypoplastic or aplastic contralaterally, cerebral ischemic stroke in the territory of the ACA and middle cerebral artery (MCA) due to hemodynamic insufficiency may occur with ipsilateral ICA occlusion. Hemodynamic studies, such as single-photon emission computed tomography (SPECT), demonstrate that cerebral perfusion and vascular reserve greatly decreased on the ICA occlusive side in such patients. Treatment by surgical revascularization of the ACA and MCA territories is difficult, and few such cases have been reported.

We report a method for revascularizing the ACA and MCA ischemic territories using bilateral superficial temporal artery (STA). We reported the case of a patient who underwent ipsilateral STA-MCA double bypass and STA-bilateral ACA bypass simultaneously. Bilateral ACAs were revascularized using an interposed Y graft of the STA anterior branch connected to the posterior branch of the STA.

The patient gained good perfusion in the ACA and MCA territories after surgery and remained without symptoms, as detected on 1-year follow-up SPECT. We discuss the etiology and surgical treatment and review the literature on hemodynamic insufficiency in the ACA areas caused by ICA occlusion.

Objective: The current treatment of choice for cavernous hemangioma is surgical resection. However, devastating hemorrhages often make surgical removal difficult. We experienced two cases of intracranial extraaxial cavernous hemangioma totally resected after intralesional injection of n-butyl cyanoacrylate (NBCA).

Case 1: A 76-year-old man presented with a right temporal skin prominence and right extreme exophthalmos. Computed tomography(CT) scan showed that a mass lesion had destroyed the temporal bone and extended to the subcutaneous, the intracranial, and the orbital space. We performed open biopsy to resect a small part of the subcutaneous lesion and encountered considerable bleeding. Pathological examination revealed a cavernous hemangioma. Transarterial embolization and then embolization by percutaneous direct puncture were performed. NBCA diluted with lipiodol widely spread through the lesion. After 4 days, surgery revealed that the lesion was completely embolized and did not bleed at all.

Case 2: A 76-year-old woman presented with bitemporal hemianopsia. Dynamic gadolinium-enhanced magnetic resonance imaging (MRI) and blood pool scintigram revealed a cavernous hemangioma of the cavernous sinus. No tumor stain was detected by cerebral angiogram. We exposed the suprasellar part of the lesion by frontotemporal craniotomy and slowly injected NBCA diluted with lipiodol. Only the suprasellar part compressing the optic chiasm was removed without major bleeding, and the other part was only embolized.

Conclusion: Embolization by percutaneous direct puncture is a safe and effective procedure for the treatment of skull base cavernous hemangioma.

A 69-year-old man was found to have a new cerebral infarction in the right middle cerebral artery region. Magnetic resonance (MR) angiography revealed right internal carotid artery (ICA) occlusion and left ICA stenosis, and diffusion-weighted image/perfusion mismatch was observed. We initiated treatment with argatroban, aspirin, and clopidogrel, but the symptoms worsened [National Institutes of Health Stroke Scale (NIHSS) 6→10] on Day 5. MR imaging revealed infarct enlargement, and we performed an emergency carotid artery stenting for left ICA stenosis to improve blood flow through the anterior communicating artery. Postoperative single-photon emission computed tomography confirmed blood flow improvement on the occluded side, and the laterality resolved. His symptoms also improved to NIHSS 6, and he was transferred to a rehabilitation hospital with modified Rankin Scale 4. In our case, intervention increased antegrade blood flow, and a wide range of blood flow improvement including the occluded side can be expected.

The superficial temporal artery to middle cerebral artery (STA-MCA) bypass is an effective surgical option to treat stenosis of the intra- or extra-cranial arteries. However, anastomosis of narrow arteries is a technically difficult procedure. Indeed, several complications including a damaged vessel during surgery have been reported. Here, we describe a successful arterial anastomosis during the STA-MCA bypass surgery. This approach comprised three steps. First, the cut end of the STA is prepared so that a neurosurgeon can easily keep the STA lumen open during anastomosis. Second, a sterile gelatin sponge is used to prevent flooding of spinal fluid. Third, sequential order of suturing in anastomosis of the STA and MCA is crucial. Combination of these tips provides an easy, fast, and solid approach, resulting in a secure anastomosis and at least one year of patency in 19 out of 20 cases.