Kunihiko Ebina

Recurrence of Cerebral Aneurysm after Initial Neck Clipping

Neck clipping has generally been believed to be among the most reliable of the operative modalities for cerebral aneurysm. However, recurrences with catastrophic outcome have been known to occur. We recently treated two patients who each had a new aneurysm at the site of the initial clipping. In both cases, the recurrence was found several years after the aneurysm neck had been closed successfully with a silver clip, which had been confirmed by intraoperative inspection and by postoperative angiographic studies demonstrating disappearance of the aneurysm. Histological examination of the recurrent aneurysm showed that the arterial wall had apparently been damaged by the clip edge, which resulted in thinning and disruption of both the muscle layer and the internal elastic lamina. Therefore, local fragility of the arterial wall adjacent to the aneurysm seems to have been the cause of the formation of a new aneurysm. The need to reinforce the thin-walled parent artery and the usefulness of high resolution computed tomography for the early detection of recurrent aneurysms are emphasized.

A clinico-experimental study on various wrapping materials of cerebral aneurysms

SummaryIn this paper, we discuss the results of a systemic study of various materials so far used for wrapping, using the intracranial arteries of 43 mongrel dogs. The findings obtained are:1.Muscle, fascia and dura observed began to show necrotic and absorbable change within 1 to 2 months after operation, suggesting their unreliability.2.Bemsheet was superior in this study in adhesiveness to the vascular wall, highly contributory to constructing a firm reinforced wall by proliferating collagen fibres in the space of stereo-reticular structure of cotton fibre. No change occurred in the cotton fibre itself with the passage of time.3.Lyodura had a poor adhesiveness to the vascular wall with detectable gap; in addition, it showed necrosis and absorption in the bending site.4.Coating with Aron alpha A had a relatively poor adhesiveness to the vascular wall and seemed to crack and disappear with time.

An angiographic study of incidence and morphology of infundibular dilatation of the posterior communicating artery

SummaryIn the last 9 years, infundibular dilatation (ID) has been sought in 260 aneurysm (An) cases and 398 carotid angiograms (CAG) to reveal its incidence and morphology. Findings were as follows:1)The incidence was about double that so far published.2)Small ID, usually triangular in shape, tended to become round as it grew larger (P<0.01).3)Large ID favored young age (P<0.05).4)In internal carotid-posterior communicating aneurysm (IC-P com-An) cases, a high incidence of ID was noted as compared to other An cases (P<0.05), and intermediate or large, round ID accounted for high ratios.5)Cases with a history of hypertension showed a high large ID ratio (P<0.05).6)Cases with well developed P com A had a high ratio of large, round ID (P<0.01).7)In cases with a large divergent angle of ICA and P com A, intermediate or large, round ID was found in high ratio (P<0.05).8)Aggressive follow-up or treatment was thought necessary in cases which posses the factors mentioned.

Expression and role of cadherins in astrocytic tumors

Cadherins are Ca2+-dependent cell adhesion molecules that play an important role in tissue formation and morphogenesis in multicellular organisms. In recent years, there have been reports of cadherin involvement in tumor invasion and metastasis. Twenty-two surgical specimens and some cultured cells were studied by immunohistochemical staining. No significant difference was observed in the patients with anaplastic astrocytoma, whereas decreased expression of N-cadherin was detected at the time of recurrence in those with glioblastoma. In these groups, cerebrospinal fluid dissemination was found, and contralateral cerebral metastases and extracranial metastases were observed. We conclude that decreased N-cadherin expression at the immunohistochemically demonstrated time of recurrence correlates with tumor invasion and dissemination of cerebrospinal fluid.

Histological change in permanently clipped or ligated cerebral arterial wall

SummaryAn investigation was carried out on clinical autopsy cases into histological changes in the vessel wall and into the surrounding tissue reaction after permanent clipping.1.There were 17 autopsy cases of cerebral aneurysm, which included seven cases treated with the Yaşargil clip, five with the Heifetz clip, and five control cases.2.Clipping period ranged from 6 days to 11 months. Both the Yaşargil and the Heifetz clips, even with long duration of clipping, caused no changes, and inflammatory reaction was slight.3.As for the necrosis of the vessel wall beneath the blade, the Yaşargil clip produced marked necrosis at the blade edge in 4 of 7 cases (57%), while the Heifetz clip caused necrosis under the midconvexity of the blades in all 5 cases (100%).4.The granulation tissue reaction round the clip began to occur after one month, and was enough to embed the blade of the clip after three months. We considered it very unlikely for a slip-out accident to occur after this stage.5.Formation of mural red thrombus and deposition of fibrin with irregular intimal thickening were noted in the aneurysmal lumen in cases clipped for less than 13 days. After one month the intimal thickening was diffuse, and organized thrombus was noted. After three months or more, the aneurysmal lumen was found to have been filled almost completely by intimal thickening. Based on the above finding, the optimum condition for temporary and permanent clips was also considered.

Clinico-statistical study on morphological risk factors of middle cerebral artery aneurysms

SummaryInfluences of various factors on postoperative outcome of 122 well-documented cases, out of a total of 151 cases of middle cerebral artery aneurysm, are discussed in this paper. The shape of the aneurysm, major axis, major axis/neck and major/minor axis ratio were correlated with the presence or absence of a bleb (p < 0.0000001), and indicated a correlation not only between aneurysmal shape and the outcome (p < 0.05) but also between preoperative seriousness and the outcome (p < 0.05). The preoperative seriousness and the grade of subarachnoid haemorrhage indicated a close correlation between each of these two parameters and the outcome (p < 0.000001 for each). Both the quantity and the colour of CSF outflow from the chiasmal cistern showed close correlation with vasospasm (p < 0.01), onset of hydrocephalus (p < 0.01) and the outcome (p < 0.001). Moreover, vasospasm and hydrocephalus grade itself also showed close correlation with the outcome (p < 0.001 and p < 0.00001). All parameters: blood pressure grade, BPmax, BPmin, BP fluctuation showed correlations not only with preoperative seriousness (p < 0.001) and the outcome (p < 0.0001) but also with subarachnoid haemorrhage frequency, number of aneurysms, and major axis/neck ratio.

Histological change in permanently clipped or ligated cerebral arterial wall. Part I. An experimental study in dogs.

SummaryIn this paper, we discuss the results of a study by light microscope of the effect of permanent clipping or ligation on the intracranial arteries of 38 operation dogs and 7 control dogs. The findings obtained are:1.In the cerebral arterial circle, necrosis could easily result from ordinary clipping or ligation because of scarce vasa vasorum.2.As for the incidence of necrosis, the greatest was found in the case of the YaŞargil clip after electric coagulation, next came the YaŞargil clip alone, next ligation, and last the silver clip. The degree of necrosis correlated with the duration of clipping in the cases treated with a spring type clip, and was influenced more by the closing strength at the time of application in the cases with non-spring type clips or ligation.3.In some of the cases ligated for long duration, recanalization was caused by the passage of the ligature through the vessel wall, suggesting that ligation is not a certain procedure if it is applied alone.4.The granulation tissue round the clip and ligature began to grow after one month. As for its degree, the most marked granulation was that caused by the silver clip, next the ligature, then the YaŞargil clip after electric coagulation, and finally the YaŞargil clip used normally; in all of them the correlation with the passage of time was noted.5.In the group of duration three months or more, concentric intimal proliferation was noted peripheral to the clip, and intimal proliferation was also noted exclusively localized to the side of a branch on the central or truncal side of a clip. This correlated in degree with the passage of time.6.Clipping and ligation are liable to cause necrosis and fragmentation, but on the other hand it was considered that rupture of the vessel wall did not result because of the reinforcing and reparative effect of the reactive granulation tissue and the intimal proliferation which developed in such a manner as to strengthen the area involved.

Changes of plasma thromboxane level in subarachnoid haemorrhage : a study with 11-dehydro-TXB2 as measuring index

SummaryChanges of plasma thromboxane level in subarachnoid haemorrhage (SAH) were studied clinically and experimentally using 11-dehydro-thromboxane B2 (11 DTX) as a measuring index. 11 DTX is a major long-lived metabolite formed from thromboxane (TX) B2, and is said to be a more reliable parameter for detecting TXA2 production in biological systems.In this clinical study, blood was sampled from the cubital vein of 10 SAH patients on the earliest possible day (day 0 or 1), during the vasospasm predilection period (day 7∼11) and in the chronic stage (day 16∼32). Plasma concentrations of 11 DTX and 6-keto-1α were measured in clinical cases.A canine SAH model was produced by the two haemorrhage methods and blood was sampled from the superior sagittal sinus before and on day 4 of the first cisternal blood injection. 11 DTX, TXB2 and platelet function were examined in each sample.In the clinical studies, plasma 11 DTX levels tended to be higher in the early stage of SAH but decreased thereafter to the normal or lower level. Plasma concentrations of 6-keto-α tended to decrease mildly during the vasospasm predilection period.In the experimental study, neither definite change of plasma 11 DTX level nor neurological deficit could be induced by the mimic SAH, while an increase in platelet aggregability and narrowing of the basilar artery were observed. 11 DTX was inferred to be a more reliable parameter of TX biosynthesis than TXB2.

A flexible aneurysm clip applier

SummaryA flexible aneurysm clip applier with a small spindle-shaped head was manufactured. It is useful for aneurysmal clipping through a narrow space and the clip can be set in various directions due to its flexibility.

Preliminary experimental study on a newly-developed coating material (liquid cellulose) for cerebral aneurysms.

SummaryWe have developed a new coating material for cerebral aneurysms consisting of cellulose. The possible usefulness of this ethyl cellulose — ethyl acetate solution (“Liquid cellulose”) as a coating material was evaluated as follows:1)The liquid cellulose (ethyl cellulose concentration, 10%; degree of polymerization, 100) and Biobond® had pHs of 7.35 and 3.16, and viscosities of 1,385 and 626 cp, respectively. The properties of the coat (N=30, M±SD) of the liquid cellulose and Biobond® at a cast coat thickness of 254 μm were as follows: coat thickness after drying (μ), 17.8±2.8 and 109.8±44.2; coat formation time (sec), 62 and 1,800; strength of the coat (gm), 432.3±51.4 and 8.0±5.6; strength index (kg/cm2), 572.8±84.7 and 2.4±1.8; and elongation index (%), 14.8±3.5 and 705±188.8, respectively. The coat using liquid cellulose was more physiological and far stronger. It was also more readily manipulated during the operation than Biobond®.2)The liquid cellulose showed excellent adhesiveness when applied to the vascular wall. Sequential histological observations for 12 months showed that the liquid cellulose remained stable without histotoxicity or cracks in the coat. These results indicate the potential usefulness of this agent for reinforcing the vascular wall.