Clipping surgery for aneurysmal subarachnoid hemorrhage in patients aged 75 years or older

Objective: The incidence rate of aneurysmal subarachnoid hemorrhage (SAH) in the elderly is increasing. Although endovascular coiling has become a major form of treatment for SAH in elderly patients, not all ruptured aneurysms can be managed with an endovascular approach. Conventional surgical clipping still plays an important role in SAH treatment. The present study was performed to assess the outcome in patients older than 75 years of age in whom ruptured aneurysms were treated by clipping surgery. Methods: This retrospective study included patients 75 years of age or older who underwent clipping surgery for ruptured cerebral aneurysms between 1988 and 2009. Age, gender, preoperative grade, Fisher grade, size, and location of the ruptured aneurysm were compared between cases showing favorable and unfavorable outcomes. Results: A total of 333 patients were analyzed. There were significant differences in preoperative grade, Fisher grade, and location of the aneurysm between the favorable and unfavorable outcome groups. In multivariate logistic regression analysis, independent predictors of unfavorable outcome were poor grade and ruptured anterior cerebral artery aneurysm, but not age of 80 years or older. Conclusions: Advanced age did not represent a risk factor for poor outcome of clipping surgery in elderly patients. Although coil embolization has been shown to be a useful form of treatment, direct surgery should also be considered.ArticleNEUROLOGICAL RESEARCH. 33(8):853-857 (2011)journal articl

Scissoring of cerebral aneurysm clips: mechanical endurance of clip twisting

Although the cerebral aneurysm clip "scissoring" phenomenon is known to occur due to twisting of the aneurysm clip blades during surgery, there have been few previous studies of scissoring. In the present study, we examined the in vitro endurance of clip twisting to assess clip scissoring. To evaluate the clip-scissoring effect, we measured torque at the rotating aneurysm clip head (Sugita and Yasargil clips) using our own manufactured product. A silicon sheet 1 mm thick was clipped at several depths (3, 6, and 9 mm), and the clip head was mechanically rotated. Straight and fenestrated clips of titanium alloy were used in the present study. Cobalt alloy straight clips were also examined. Preliminary experiments indicated that torque values during clip head rotation dropped when the blades crossed. In addition, torque values before blade crossing showed resistance to slippage of the blades. Torque values of both Sugita and Yasargil clips were directly proportional to the blade depth. There were no differences between straight and fenestrated Sugita clips. Although the torque was greater in cobalt alloy than titanium alloy Sugita clips, the torque values of Yasargil cobalt and titanium clips were identical. We found some differences in torque values during clip head rotation between Sugita and Yasargil clips. Based on the results of twisting experiments, scissoring is likely to occur when occluding the neck of the aneurysm only with the tips of long clip blades.ArticleNEUROSURGICAL REVIEW. 35(2):219-224 (2012)journal articl

Multi-messenger signals of long-term core-collapse supernova simulations : synergetic observation strategies

The next Galactic supernova is expected to bring great opportunities for the direct detection of gravitational waves (GW), full flavor neutrinos, and multi-wavelength photons. To maximize the science return from such a rare event, it is essential to have established classes of possible situations and preparations for appropriate observations. To this end, we use a long-term numerical simulation of the core-collapse supernova (CCSN) of a 17 solar-mass red supergiant progenitor to self-consistently model the multi-messenger signals expected in GW, neutrino, and electromagnetic messengers. This supernova model takes into account the formation and evolution of a protoneutron star, neutrino-matter interaction, and neutrino transport, all within a two-dimensional shock hydrodynamics simulation. With this, we separately discuss three situations: (i) a CCSN at the Galactic Center, (ii) an extremely nearby CCSN within hundreds of parsecs, and (iii) a CCSN in nearby galaxies within several Mpc. These distance regimes necessitate different strategies for synergistic observations. In a Galactic CCSN, neutrinos provide strategic timing and pointing information. We explore how these in turn deliver an improvement in the sensitivity of GW analyses and help to guarantee observations of early electromagnetic signals. To facilitate the detection of multi-messenger signals of CCSNe in extremely nearby and extragalactic distances, we compile a list of nearby red supergiant candidates and a list of nearby galaxies with their expected CCSN rates. By exploring the sequential multi-messenger signals of a nearby CCSN, we discuss preparations for maximizing successful studies of such an unprecedented stirring event.Comment: Link to the online material (lists of nearby RSG candidates and local galaxies) is added, also available from http://th.nao.ac.jp/MEMBER/nakamura/2016multi/index.htm

Constructing Goeritz matrix from Dehn coloring matrix

Associated to a knot diagram, Goeritz introduced an integral matrix, which is now called a Goeritz matrix. It was shown by Traldi that the solution space of the equations with Goeritz matrix (precisely, unreduced Goeritz matrix called in his paper) as a coefficient matrix is isomorphic to the linear space consisting of the Dehn colorings for a knot. In this paper, we give a construction of a Goeritz matrix from a Dehn coloring matrix, from which Dehn colorings are induced. Moreover, if the knot diagram is prime, we give a purely algebraic construction of a Goeritz matrix from a Dehn coloring matrix.Comment: 10 pages, 6 figure

Horizontal contralateral approach for the distal anterior cerebral artery aneurysm: technical note

Background: The authors present a modified interhemispheric approach for the distal ACA aneurysm to resolve several problems including the narrow surgical corridor, the difficulty of proximal control, and the aneurysmal projection toward the surgeon. Methods: We refined the positions of the patient's head and the surgeon. The patient's head is fixed with flexion and tilted to the contralateral side. The surgeon sits on the contralateral side of the patient and not on the cranial side. Results: The present approach allows the surgeon to comfortably use both hands in the horizontal operative filed, to obtain a minimum retraction of the brain, and to easily secure the proximal artery. Conclusions: This modified interhemispheric approach is useful for a patient with the distal ACA aneurysm.ArticleSURGICAL NEUROLOGY. 72(1):65-68 (2009)journal articl

Revisit of aneurysm clip closing forces: comparison of titanium versus cobalt alloy clip

Although closing force of cobalt alloy clip is well studied, there is only little information of titanium alloy clip available in the literature. In the present study, we examined and compared closing forces of various types and points of cerebral titanium and cobalt aneurysm clips for cerebral aneurysms. Straight, temporary, bayonet, angled, and fenestrated titanium or cobalt alloy clips were tested by measuring the closing forces at various points along their blade length. Closing forces of all the tested clips linearly increased from tip to base of clip blades. Sugita Titanium II clips had bigger closing forces than Elgiloy clips in all type clips except for the temporary clips. The closing forces of Sugita Titanium II and Yasargil titanium clips were similar in straight permanent type clip although there were some differences in closing forces between other types of Sugita and Yasargil clips. Our data showed that the closing forces differed depending not only on manufacturers but also on materials and shapes.ArticleNEUROSURGICAL REVIEW. 36(1):133-137 (2013)journal articl

Suboccipital Approach for Primitive Trigeminal Artery Obliteration Associated with Cavernous Aneurysm

OBJECTIVE: A 63-year-old woman presented with diplopia resulting from abducens paralysis. Examination revealed a giant cavernous aneurysm supplied by the internal carotid artery (ICA) and primitive trigeminal artery (PTA) via the vertebrobasilar system. METHODS: After evaluation of balloon test occlusion (BTO) at the distal side of the PTA origin, the aneurysm was treated with PTA obliteration through the suboccipital route in the lateral position followed by cervical carotid ligation with superficial temporal artery-to-middle cerebral artery anastomosis in the supine position. RESULTS: The aneurysm showed marked shrinkage after the surgery. CONCLUSION: PTA obliteration through the retrosigmoid opening is a therapeutic surgical option in a patient with a cavernous aneurysm supplied by the PTA.ArticleWORLD NEUROSURGERY. 74(4-5):494-496 (2010)journal articl

Outcome predictors of open embolectomy in middle cerebral artery occlusion

Objective: The purpose of this paper was to analyse the outcome of the patients with acute middle cerebral artery (MCA) occlusion treated by open embolectomy. Methods: A clinical chart review was retrospectively conducted for 30 patients who had MCA occlusion and were treated with open embolectomy. According to the Glasgow Outcome Scale, the patients' outcome at discharge is divided in two groups: favorable outcome (good recovery and moderate disability) or unfavorable outcome (severe disability, vegetative state and death). The following variables between the favorable and unfavorable outcomes were analysed: age, sex, Glasgow Coma Scale score on admission, affected side, occlusion site, occlusion time, atrial fibrillation on electrocardiogram, fibrinolysis, aphasia, hemiparesis and hemorrhagic infarction after surgery. Results: The outcomes of 30 patients were favorable in 16 patients (good recovery in nine and moderate disability in seven) and unfavorable in 14 patients (severe disability in 12, vegetative state in one and death in one). The M1 occlusion and fibrinolysis performance were more frequent in the unfavorable outcome group than in the favorable one. Logistic regression analysis with a stepwise method indicated that the only occlusion site was independently associated with the unfavorable outcome. The occlusion time >360 minutes was not the predictor of the unfavorable outcome. Discussion: The outcome of patients with MCA occlusion treated by the open embolectomy depends on the occlusion site and the fibrinolysis performance in the present study. The M1 occlusion is also the independent risk factor of the unfavorable outcome. However, the occlusion time itself has no relation to the unfavorable outcome. These results indicate that therapeutic time windows vary in individuals probably due to the collateral blood flow.ArticleNEUROLOGICAL RESEARCH. 31(9):892-894 (2009)journal articl