Yoshihide Nagamine

A Pitfall in the Surgery of a Recurrent Aneurysm after Coil Embolization and Its Histological Observation: Technical Case Report

OBJECTIVE AND IMPORTANCE This case report details the unexpected surgical difficulty encountered in treating a recurrent aneurysm after coil embolization and presents the histological findings of the resected aneurysm. This is only the second reported case of histological description of an aneurysm after coil embolization in a human. CLINICAL PRESENTATION A 60-year-old woman experienced a 3-month history of chronic headache. Neuroimaging studies demonstrated a 2-cm anterior communicating artery aneurysm. The aneurysm was treated with a two-stage endovascular coil embolization, resulting in almost complete occlusion of the aneurysm. A cerebral angiogram at 6-month follow-up demonstrated slight refilling of the aneurysm, and angiography at 18 months showed a marked increase in the size of the small remnant. Therefore, the patient was referred for direct surgical repair of the aneurysm. INTERVENTION The distal aneurysm dome, which had been packed with the coils and thrombus, was resected under temporary arterial trapping. An intra-aneurysmal endarterectomy was required, because the aneurysm wall developed intimal dissection that extended to the orifices of afferent and efferent arteries. The aneurysm was then obliterated with multiple clips, reconstructing the patent vessel lumen. However, the patient awoke from surgery with left hemiparesis. A postoperative angiogram disclosed occlusion of the right anterior cerebral artery. An histological study of the thrombosed aneurysm showed that the luminal surface of thrombus was not lined by endothelium. CONCLUSION This case demonstrated not only the limited efficacy of coil embolization treatment for wide-necked aneurysms but also the potential difficulty in the direct surgical repair for such recurrent aneurysms.

Indirect revascularization for moyamoya disease: Is there a beneficial effect for adult patients?

BACKGROUND It is generally accepted that excellent development of collateral circulation can be achieved through indirect nonanastomotic bypass procedures for pediatric patients with moyamoya disease. However, there are no definitive conclusions about the effect of indirect revascularization for adult patients. To clarify the value of indirect bypass surgery for adult moyamoya disease, we have analyzed their follow-up angiographic results in comparison with those of the pediatric patients. METHODS Between 1989 and 1993, 23 patients underwent combined direct and indirect bypass surgery. They consisted of 16 adults (mean age, 35; range, 20-59) and seven children (mean age, 10; range, 3-16). The main symptoms were those due to cerebral ischemia in all but 1 of 23 patients. Preoperative cerebral blood flow studies showed all patients to have decreased vascular reserve (misery perfusion). Postoperative follow-up angiography was done in all patients at a median of 6 months after the surgery. RESULTS All pediatric patients showed good or moderate development of collaterals through the indirect bypass. Among the adult group, seven patients aged 20 to 29 had angiographic results similar to those of the pediatric group . On the other hand, nine patients older than 30 had results contrary to those of pediatric patients: (1) the degree of indirect revascularization declined to moderate or poor grades (especially in patients older than 40) and (2) the degree of direct bypass filling improved to high or medium grades. CONCLUSIONS The results suggest that advancing age apparently affects the development of collateral formation through the indirect bypass. Consequently, direct bypass is thought to be the main treatment option for patients older than 40.

How to treat incidental cerebral aneurysms : a review of 139 consecutive cases

BACKGROUND Together with current advances in neuroimaging techniques, the chance of incidental discovery of unruptured cerebral aneurysms has increased and the selection of their appropriate management remains controversial. To provide current data about management results of patients with incidental cerebral aneurysms, we have made a retrospective review of 139 consecutive patients treated either by surgical or conservative means. METHODS The surgical indication for each patient was decided, carefully considering several factors respectively, including the surgical difficulty, aneurysm size, patients age, and medical condition. RESULTS Forty-nine patients were managed conservatively. Eight (16%) of those conservatively managed patients had intracranial hemorrhage due to aneurysm rupture during the follow-up period (mean, 4.3 years). Seven of these eight patients died from a fatal subarachnoid hemorrhage (SAH). The follow-up data showed that the mean size of aneurysms with late hemorrhage was significantly larger than that of aneurysms without subsequent rupture. It was also confirmed that none of the 26 tiny aneurysms smaller than 4 mm in diameter had ruptured. Ninety patients harboring 119 incidental aneurysms less than 25 mm in diameter underwent surgery. There was no surgical mortality or morbidity in this series. CONCLUSIONS These excellent surgical results were presumably achieved due to the strict patient selection. In respect to the size of aneurysms, it seems to be justified to recommend surgery for patients with aneurysms larger than 5 mm in diameter.

New embolization method using estrogen: effect of estrogen on microcirculation

To ascertain the mechanism of action of estrogen administered by a new embolization method, developed by the authors as a treatment method for dural arteriovenous malformations, conjugated estrogens were injected into the mesenteric artery of rabbits, and microcirculatory changes in the dominant areas were studied biomicroscopically. Conjugated estrogen induced sludging and stasis in the microcirculation, approximately in proportion to the concentration and dose.

Types of unruptured cerebral aneurysms reviewed from operation video-recordings

SummaryTo estimate the proportion of unruptured cerebral aneurysms with thin-walled sac, we have analyzed the operative findings of 78 incidental cerebral aneurysms found in 51 consecutive surgical cases by reviewing of intra-operative videotape recordings. Among 78 unruptured aneurysms, 23 (30%) were evaluated as thick-walled aneurysms (Type A), 39 (50%) with partially thin-walled sac (Type B) and 16 (20%) with entirely thin wall sacs (Type C). The mean size of Type A aneurysms was 10.4 mm (ranging from 3 to 22 mm), in Type B it was 9.8 mm (ranging 4 to 25 mm) and in Type C it was 4.4 mm (between 2–12 mm). Approximately two-thirds of Type C aneurysms were 4 mm in size or smaller, and Type C aneurysms were significantly smaller than Type A aneurysms. In summary, this preliminary study has provided two original data. 1) About 70% of incidental unruptured aneurysms have a partially or entirely thin-walled sac. 2) Many of the small aneurysms have an entirely thin sac. Assuming that thin-walled aneurysms are at a high risk of subsequent rupture, the surgical intervention for incidental unruptured aneurysms may be recommended irrespective of their size if the surgical risk is considered low.

Non-transcallosal ipsilateral area 3b responses to median nerve stimulus

We report two patients with left hemisphere lesions who had no normal left hemispheric responses to right median nerve stimulus on magnetoencephalography but displayed right area 3b responses. One patient had suffered a severe left hemispheric contusion and the other left hemispheric infarction. Equivalent current dipoles of these ipsilateral responses were detected on the central sulcus adjacent to the location of the N20m response to left median nerve stimulus. The somatosensory afferent pathway from the hand may extend directly to the ipsilateral area 3b without following the transcallosal pathway in at least part of the population.

An experimental study of vascular damage in estrogen-induced embolization

Temporal sequences of estrogen-induced embolization were studied in both in vivo and in vitro models. Infusion of the estrogen compound into rat mesenteric artery caused local spherocytosis and severe rapid degeneration of endothelial cells, followed by injury to the underlying muscle cells and fibroblasts. These changes were regarded as mainly the results of the embolization effect of conjugated estrogen. A study of cultured vascular endothelial cells suggested narrow margins of effective drug concentrations for cell damage. Also, nuclear disintegration with relative sparing of cytoplasmic constituents seemed to be characteristic of estrogen-induced cell damage in both in vivo and in vitro models.

Somatosensory evoked fields in comatose survivors after severe traumatic brain injury

OBJECTIVE To evaluate the cortical function quantitatively in patients in the chronic phase of severe traumatic brain injury. METHODS Thirteen patients with severe traumatic brain injury due to traffic accident followed by persistent consciousness disturbance and disability were studied. Somatosensory evoked magnetic fields (SEFs) for unilateral median nerve stimulation were measured using a whole-head magnetoencephalography system. The latency and electrical current dipole (ECD) moment for the N20m, P30m, N45m and P60m components were calculated and compared with those of 14 age-matched healthy adults. RESULTS The peak latency of N20m was longer (P<0.05) and those of P30m and N45m were shorter (P<0.01) in the patients than in normal adults. The ECD moment of N20m and P30m was smaller and that of N45m and P60m was larger in the patients than in normal adults (P<0.01). CONCLUSIONS These results can be explained by the hypothesis that diffuse brain injury induces decreased and delayed input of the somatosensory afferent and compensational amplification of the response in the primary somatosensory cortex. Middle-latency SEFs may be applicable as a cortical functional measure for patients with severe traumatic brain injury.

Predictors of Recovery from Traumatic Brain Injury-Induced Prolonged Consciousness Disorder

We investigated the clinical predictors of the degree of recovery in patients with prolonged disorders of consciousness (PDC) caused by traumatic brain injury. Fourteen patients with PDC underwent two diffusion tensor imaging (DTI) studies; the first and second scans were performed at 345.6 ± 192.6 and 689.1 ± 272.2 days after the injury, respectively. In addition to the temporal changes in each of these diffusion parameters, fractional anisotropy (FA), mean diffusivity, axial diffusivity (AD), and radial diffusivity were assessed over a 1-year period. Relationship of clinical and DTI parameters with recovery from PDC (RPDC) was evaluated using Spearmans rank-correlation and stepwise multiple linear regression analysis. The mean FA and number of voxels with FA values > 0.4 (VsFA0.4) were significantly decreased at the second scan. A significant positive correlation was observed between the degree of RPDC and mean FA (r = 0.60) and VsFA0.4 (r = 0.68) as well as between the difference in VsFA0.4 (r = 0.63) and AD (r = 0.54) between the first and second scans. On multiple linear regression analysis, initial severity of PDC and the difference in AD remained significantly associated with the degree of RPDC. The microstructural white matter changes observed in this study indicate their potential relation with the degree of RPDC over the longer term.