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Hiroshi Kashimura, Kuniaki Ogasawara, Yoshitaka Kubo, Yasunari Otawara and Akira Ogawa

✓ A technique is described for removing previously placed aneurysm clips and applying new aneurysm clips for the treatment of regrown or reruptured cerebral aneurysms in patients more than 10 years after the original clipping of the aneurysm neck. The adherent tissue covering previously placed clips is cut just on and alongside the clips themselves using a small scalpel. Using the clip applicator, gentle pressure is applied to open the clip blade as little as possible. The aneurysm clip is carefully slid out along the line where the clip blade has resided, and a new aneurysm clip is applied. The procedure was successfully accomplished in four patients. Whereas three of these patients had an uneventful postoperative course, the remaining patient experienced transient right oculomotor nerve palsy and left-sided motor weakness. The present technique is a useful procedure for treatment of regrown or reruptured cerebral aneurysms occurring a significantly long time after initial clipping of an aneurysm neck.

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Yasunari Otawara, Miguel M. Endo, Kuniaki Ogasawara, Yoshitaka Kubo, Akira Ogawa and Kouichi Watanabe

Object

Aneurysm clip reliability after long-term implantation in vivo has not been examined. In this study the authors evaluated the mechanical properties and surface elemental composition of Co-Cr alloy aneurysm clips implanted for more than 10 years in patients with cerebral aneurysms.

Methods

Five aneurysm clips implanted for ruptured or unruptured intracranial aneurysms were retrieved and examined. New aneurysm clips were applied to the regrown aneurysms. The implantation period ranged from 11 to 20 years. Four new and unused aneurysm clips were also examined as controls. The mechanical properties of the clips were tested by measuring their closing force and bending strength. The surface elemental composition of the aneurysm clips was evaluated using x-ray photoelectron spectroscopy. The closing force of the retrieved clips exceeded the minimum force requirement at the time of manufacture. The bending strength was similar between the retrieved and control clips. Chromium oxide was the predominant constituent on the surface of all clips, and its concentration on the retrieved clips was higher than that on the control clips.

Conclusions

Data in the present study demonstrated that Co-Cr alloy aneurysm clips retain their mechanical properties in vivo for a long time, which indicates the reliability of these clips.

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Kuniaki Ogasawara, Yoshitaka Kubo, Nobuhiko Tomitsuka, Masayuki Sasoh, Yasunari Otawara, Hiroshi Arai and Akira Ogawa

✓ The authors describe transposition of the posterior inferior cerebellar artery (PICA) to the vertebral artery (VA) combined with parent artery occlusion for the treatment of VA aneurysms in cases in which a clip could not be applied because of the origin of the ipsilateral PICA. The aneurysm is trapped through a lower lateral suboccipital craniectomy. The PICA is then cut just distal to the aneurysm, and the PICA and VA proximal to the aneurysm are anastomosed in an end-to-end or end-to-side fashion.

The surgical procedure was successfully performed in two patients, each of whom had hypoplastic occipital arteries (OAs). The PICA contralateral to the lesion was hypoplastic in one patient and distant to the ipsilateral PICA in the other patient. Mild transient dysphagia developed postoperatively in one patient due to glossopharyngeal and vagus nerve palsy, and the other patient had an uneventful postoperative course. In both patients, postoperative cerebral angiography demonstrated good patency of the transposed PICA. These results show that transposition of the PICA to the VA is a useful procedure for the reconstruction of the PICA when parent artery occlusion is necessary to exclude a VA aneurysm involving the origin of the PICA and when OA–PICA anastomosis or PICA–PICA anastomosis cannot be performed.

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Yoshitaka Kubo, Kuniaki Ogasawara, Nobuhiko Tomitsuka, Yasunari Otawara, Mikio Watanabe and Akira Ogawa

✓ A technique combining wrapping and clip occlusion of aneurysms by using polytetrafluoroethylene (PTFE) for treatment of ruptured blisterlike aneurysms of the supraclinoid internal carotid artery (ICA) is described. The diameter of the abnormal arterial lesion along the long axis of the ICA and the distance between the origin of the ophthalmic artery and the origin of the posterior communicating artery (PCoA), or the origin of the PCoA and the origin of the anterior choroidal artery are measured intraoperatively; a strip of PTFE membrane is then trimmed with scissors to match this diameter and distance. After temporarily occluding the cervical ICA, the intracranial ICA that includes the lesion is wrapped with the strip of PTFE, and one or more aneurysm clips are applied parallel to the ICA. This procedure was successfully accomplished in six patients, all of whom had an uneventful postoperative course with no recurrent subarachnoid hemorrhage during the follow-up period. “Wrap-clipping” using PTFE is a useful procedure for management of ruptured blisterlike aneurysms of the ICA.

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Wataru Yanagihara, Kohei Chida, Masakazu Kobayashi, Yoshitaka Kubo, Kenji Yoshida, Kazunori Terasaki and Kuniaki Ogasawara

OBJECTIVE

Some adult patients with moyamoya disease (MMD) undergoing revascularization surgery show an improvement or decline in cognition postoperatively. Revascularization surgery for ischemic MMD augments cerebral blood flow (CBF) and improves cerebral oxygen metabolism. However, cerebral hyperperfusion, which is a short-term, major increase in ipsilateral CBF that is much greater than the metabolic needs of the brain, sometimes occurs as a complication. Cerebral hyperperfusion produces widespread, minimal injury to the ipsilateral white matter and cortical regions. The aim of the present prospective study was to determine how changes in CBF due to arterial bypass surgery affect cognitive function in adult patients with symptomatic ischemic MMD and misery perfusion.

METHODS

Thirty-two patients with cerebral misery perfusion, as determined on the basis of 15O gas positron emission tomography, underwent single superficial temporal artery–middle cerebral artery (M4 in the precentral region) anastomosis. Brain perfusion single-photon emission computed tomography (SPECT) studies were performed preoperatively, on the 1st postoperative day, and 2 months after surgery. Neuropsychological tests were also performed preoperatively and 2 months after surgery.

RESULTS

Postoperative neuropsychological assessments demonstrated cognitive improvement in 10 cases (31%), no change in 8 cases (25%), and decline in 14 cases (44%). Based on brain perfusion SPECT and symptoms, 10 patients were considered to have cerebral hyperperfusion syndrome, and all of these patients exhibited a postoperative decline in cognition. Relative precentral CBF on the 1st postoperative day was significantly greater in patients with postoperative cognitive decline (167.3% ± 15.3%) than in those with improved (105.3% ± 18.2%; p < 0.0001) or unchanged (131.4% ± 32.1%; p = 0.0029) cognition. The difference between relative precentral CBF 2 months after surgery and that before surgery was significantly greater in patients with postoperative cognitive improvement (17.2% ± 3.8%) than in those with no postoperative change (10.1% ± 2.4%; p = 0.0003) or with postoperative decline (11.5% ± 3.2%; p = 0.0009) in cognition.

CONCLUSIONS

Cerebral hyperperfusion in the acute stage after arterial bypass surgery impairs cognitive function. An increase in CBF in the chronic stage without acute-stage cerebral hyperperfusion improves cognitive function in adult patients with symptomatic ischemic MMD and misery perfusion.

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Yasunari Otawara, Kuniaki Ogasawara, Hiroshi Kashimura, Yoshitaka Kubo, Akira Ogawa and Kouichi Watanabe

The mechanical properties of titanium-alloy aneurysm clips after long-term implantation in the human cranium are unclear. The characteristics of a Yasargil titanium aneurysm clip were evaluated after long-term implantation for 12 years in a patient with a cerebral aneurysm. The closing forces of the retrieved clip before and after implantation were approximately equal. The bending test showed no differences between the retrieved and control clips. Titanium oxide and calcium were identified on the surface of the retrieved clip, which indicated the formation of corrosion-resistant layers. Titanium-alloy clips retain their mechanical properties in the human cranium for a long time.

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Yoshitaka Kubo, Kuniaki Ogasawara, Akira Kurose, Shunsuke Kakino, Nobuhiko Tomitsuka and Akira Ogawa

Although aortic or cardiac complications are common in patients with Marfan syndrome, the presence of an intracranial aneurysm is comparatively rare. In this study, the authors report on their experience with resection of a ruptured fusiform aneurysm of the posterior cerebral artery in a 30-year-old woman with Marfan syndrome. Microscopic examination of the resected tissue showed many Alcian blue–staining deposits, consistent with the presence of mucopolysaccharide in the tunica media and focal fragmentation of the internal elastic lamina.

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Yoshitaka Kubo, Takahiro Koji, Hiroshi Kashimura, Yasunari Otawara, Akira Ogawa and Kuniaki Ogasawara

Object

The prevalence of patients with asymptomatic unruptured intracranial aneurysms (UIAs) increases with the advancing age of the general population. The goal of the present study was to identify risk factors for the growth of UIAs detected with serial MR angiography (MRA) in patients 70 years of age or older.

Methods

This prospective study enrolled 79 patients (age range 70–84 years) with 98 UIAs. Patients were followed up every 4 months, including an assessment of the aneurysm diameter and morphological changes on MRA, neurological status, and other medical conditions. Aneurysm growth was categorized into two different patterns on the basis of the MRA findings: 1) maximum increase in aneurysm diameter of 2 mm or more; and 2) obvious morphological change, such as the appearance of a bleb.

Results

The mean duration of follow-up was 38.5 months (250.2 patient-years). Aneurysm rupture did not occur, but aneurysm growth was observed in 8 aneurysms (8 patients) during the study period. Univariate analysis showed that female sex, patient age ≥ 75 years, and an aneurysm location in the internal carotid artery (ICA) or middle cerebral artery (MCA) were associated with aneurysm growth (p = 0.04, p = 0.04, and p < 0.001, respectively). Multivariate analysis demonstrated that female sex was the only independent predictor of aneurysm growth (p = 0.0313, OR 2.3, 95% CI 1.3–30.2).

Conclusions

Female sex is an independent risk factor for the growth of UIAs in elderly patients. In addition, an age ≥ 75 years and aneurysm location in the ICA or MCA are characteristics that may warrant additional attention during follow-up imaging.

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Shunsuke Kakino, Kuniaki Ogasawara, Yoshitaka Kubo, Hiroshi Kashimura, Hiromu Konno, Atsushi Sugawara, Masakazu Kobayashi, Makoto Sasaki and Akira Ogawa

Object

Although angioplasty and stent placement for vertebral artery (VA)–origin stenosis have been performed using endovascular techniques, a high likelihood of restenosis has been observed in the long term. Therefore, the authors assessed the long-term clinical and angiographic outcomes in patients after VA–subclavian artery (SA) transposition.

Methods

Thirty-six patients (31 men, 5 women; mean age 64.3 years, range 46–76 years) underwent clinical evaluation (modified Rankin Scale [mRS]) and cervical angiographic evaluation preoperatively and within 1 month of and 6 months after VA-SA transposition undertaken to treat symptomatic stenosis of VA origin.

Results

Postoperative neurological deficits due to intraoperative brain ischemia did not occur, and MR imaging demonstrated no new postoperative ischemic lesions in any of the patients. One patient died of acute myocardial infarction 2 months after surgery and another developed a left thalamic hemorrhage (mRS score of 5) at 42 months postsurgery. None of the remaining 34 patients experienced further ischemic events, and the mRS score in all of these patients remained unchanged during a mean follow-up period of 54 months. The degree of VA-origin stenosis (preoperative mean 84%) was reduced to ≤ 30% after surgery (mean 2%). Long-term follow-up angiography in 29 patients (81%) revealed the absence of restenosis, defined as > 50% luminal narrowing, in all of them.

Conclusions

The clinical and angiographic long-term outcomes demonstrated here suggest that VA-SA transposition will be useful in patients with symptomatic stenosis of VA origin.

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Hiroshi Kashimura, Kuniaki Ogasawara, Yoshitaka Kubo, Shunsuke Kakino, Kenji Yoshida, Masayuki Sasoh, Hajime Takahashi, Kenji Suzuki and Akira Ogawa

✓ A technique for exposing the vertebrobasilar junction with traction of the dentate ligament is described for treatment of large vertebral artery (VA) aneurysms via the far lateral suboccipital approach with partial condylar resection. The most rostral attachment of the dentate ligament is divided above the site where the VA pierces the dura mater. A traction suture is placed into the dentate ligament and gently retracted using mosquito forceps. As a result, the medulla oblongata is lifted dorsally and slightly rotated by the divided and retracted dentate ligament, allowing an approach from a more superior or inferior direction. The present technique is useful for the treatment of large thrombosed VA aneurysms.