Risk Factors for Visual Impairments in Patients with Unruptured Intradural Paraclinoid Aneurysms Treated by Neck Clipping without Bypass Surgery

OBJECTIVE

Although paraclinoid aneurysms are now frequently referred for endovascular treatment, the durability of obliteration is still to be determined. Therefore, direct surgery for paraclinoid aneurysms still remains indispensable. The present study aimed to evaluate the risk factors for the visual impairments in patients with unruptured intradural paraclinoid aneurysms.

METHODS

The data of 133 patients with 136 aneurysms treated by neck clipping without bypass surgery was evaluated. Visual impairments included decreased visual acuity and visual field defect. The aneurysm was classified into superior projecting aneurysm, ventral projecting aneurysm, and carotid cave aneurysm. Plug-in method was defined as filling interspace, which was formed between the internal carotid artery and the sutured dura in case of detachment of the dural ring.

RESULTS

Postoperative new visual impairments were observed in 30 aneurysms (22%). During the follow-up period (median, 600 days), postoperative new visual impairments continued in 23 aneurysms (17%). Multivariate analysis showed that carotid cave location and plug-in method were related to new visual impairments at 30 days (odds ratio [OR], 2.6; 95% confidence interval [CI] 1.1-6.1; P = 0.031 and OR, 4.1; 95% CI 1.4-12; P = 0.008) and at 6 months (OR, 4.1; 95% CI 1.5-11; P = 0.005 and OR, 3.3; 95% CI 1.1-11; P = 0.045).

CONCLUSIONS

The present study showed that carotid cave location and plug-in method during dural closures were related to postoperative continued visual impairments. Neurosurgeons should carefully consider the surgical indication for unruptured carotid cave aneurysms and avoid plug-in methods.

Radical surgical treatment for recurrent giant fusiform thrombosed vertebral artery aneurysm previously coiled

Background:

Fusiform aneurysms are rare (<1%) and the underlying pathophysiology is not well known. Endovascular coiling is the standard of treatment; however, a surgical procedure with vascular reconstruction by excluding the pathological segment of the vessel and restoring the blood flow, seems to be the most effective and definitive treatment.

Case Description:

We report a patient who presented a fusiform vertebral artery aneurysm previously coiled which developed a giant enlargement and a new contralateral fusiform aneurysm. Hemodynamic changes resulting in the formation of contralateral aneurysm might be the result of aneurysm occlusion without revascularization. In addition, continued blood flow to the aneurysmal wall through the vasa vasorum might result in aneurysm recanalization or regrowth. In order to account for these possible sources of complications, we performed a vascular reconstruction with high and low flow bypasses after trapping the aneurysm.

Conclusions:

We hypothesize that, in this and similar cases, surgical vascular reconstruction should be the first and definitive treatment under experienced cerebrovascular surgeons.

The efficiency of the new Yasargil titanium fenestrated mini-clips for ideal clipping of a cerebral aneurysm

BACKGROUND

The fenestrated clip is sometimes useful in limited approach angle and narrow working space. However, before the development of the new Yasargil titanium fenestrated mini-clip, the only variations of fenestrated clips were those of larger sizes. And those larger clips have a problem of the triangle-shaped gap at the proximal end of the blade. The authors describe the efficiency, limitations and surgical technique of using the Yasargil titanium fenestrated mini-clip.

METHODS

Fifty-nine cases of aneurysms were treated using these mini-clips. Aneurysm location, size and dome neck ratio, mean follow-up period, neck remnant, and recurrence rate were also analyzed. Among these cases, we present eight characteristic cases, including a case with aneurysm recurrence, and we review the problems associated with the triangle-shaped gap at the proximal end of the clip.

RESULTS

The average size of the aneurysms was 5.57 mm, and the dome neck ratio was >2.0 in 1.69%, >1.5 in 11.8%, >1.2 in 35.6%, and <1.2 in 50.8% of cases. The mean follow-up period for the 59 cases was 5.5 months (range, 0.5-16 months). Angiographic recurrence of the treated portion occurred in 1 case (1.7%), including an aneurysm in the basilar artery tip aneurysm.

CONCLUSION

The availability of the Yasargil titanium fenestrated mini-clip increases the options for clipping to minimize the remnant of the clipped aneurysm. However, there is still concern over the triangular space at the base of the blade, especially when treating an aneurysm with a thin vessel wall. Therefore, modification of the clipping technique is sometimes needed.

Surgical Treatment of 127 Paraclinoid Aneurysms with Multifarious Strategy: Factors Related with Outcome

BACKGROUND

Few reports have been published discussing surgical outcomes of paraclinoid aneurysms using multifarious treatments such as high-flow bypass.

MATERIAL AND METHODS

We retrospectively analyzed findings from 127 consecutive patients (19 males, mean age at surgery: 56.8 years, range: 19-81 years) at our hospital. The size of aneurysms ranged from 2.7-43.2 mm (mean: 6.9 mm). Extradural anterior clinoidectomy was used to clip small aneurysms. As large or giant aneurysms required a longer temporal occlusion period and often could not undergo simple clipping, high-flow bypass with anterior clinoidectomy or cervical internal carotid ligation was performed to reduce aneurysm blood flow and induce thrombosis. We reviewed a postoperative modified Rankin Scale (mRS), radiographic outcomes, cerebral infarction, and visual disturbance. In addition, we analyzed factors relating to the outcomes and complications, with focus on the aneurysm size, location, and type of surgical treatment.

RESULTS

Good outcomes were achieved in all patients, as follows: mRS 0:100, mRS 1:16, mRS 2:11, and mRS 3-6:0. Among the 127 patients, complete exclusion of aneurysm was achieved in 119 cases (93.7%). Postoperative morbidity included ischemic lesions in 11 (8.6%) and visual disturbance in 24 (18.8%). Significant statistical differences were observed between ischemic complication and aneurysm size and location (P = 0.0001) and surgical treatment (P < 0.0001).

CONCLUSION

Surgical treatment of unruptured paraclinoid aneurysm has high efficacy with good outcomes and a high rate of complete exclusion. However, the rate of visual disturbance is relatively high. Careful surgical techniques and intraoperative monitoring are therefore required.

Effects of Clot Removal by Meticulous Irrigation and Continuous Low-Dose Intravenous Nicardipine on Symptomatic Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage Treated by Clipping

BACKGROUND

Symptomatic cerebral vasospasm (SCV) is the second most common of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH) after rebleeding. Blood breakdown products are one of the leading causes of vasospasm. We hypothesized that meticulous subarachnoid clot removal in addition to continuous low-dose intravenous nicardipine (CLIN) could reduce the incidence of SCV.

METHODS

SCV was defined as new focal neurologic signs, consciousness deterioration, or both when the cause was believed to be ischemia attributable to vasospasm after other possible causes of worsening were excluded. Initial brain damage was defined as continued consciousness disturbance after clipping without acute hydrocephalus, ischemic lesions, or focal sign before clipping. Poor outcome was defined as a Glasgow Outcome Scale score of 3-5 at 30 days. We compared the variables for 460 aSAH patients with and without SCV, and with and without poor outcome by multivariate analysis.

RESULTS

All patients underwent clipping with meticulous irrigation for clot removal, and SCV was observed in 56 patients (12%). SCV was observed in 2 patients (2.9%) among 70 patients treated with CLIN. There was a higher proportion of patients who were older than 65 years (P = 0.032) and female (P = 0.038), and a lower proportion of patients with CLIN (P = 0.026) among patients with SCV. The outcomes for 109 patients (27%) were poor; age greater than 65 years (P < 0.0001) and initial brain damage (P = 0.008) were related to the poor outcomes.

CONCLUSIONS

The present study showed that meticulous irrigation for clot removal and CLIN might reduce the incidence of SCV in patients with aSAH.

Olfactory preservation during anterior interhemispheric approach for anterior skull base lesions: technical note

Anosmia is not a rare complication of surgeries that employ the anterior interhemispheric approach. Here, we present a fibrin-gelatin fixation method that provides reinforcement and moisture to help preserve the olfactory nerve when using the anterior interhemispheric approach and describe the results and outcomes of this technique. We analyze the outcomes with this technique in 45 patients who undergo surgery for aneurysms, brain tumors, or other pathologies via the anterior interhemispheric approach. Anosmia occurred in 4 patients (8.8%); it was transient in 2 (4.4%) and permanent in the remaining 2 (4.4%). Brain tumors clearly attached to the olfactory nerve were resected in the patients with permanent anosmia. We found a significant difference in the presence of anosmia between patients with or without lesions that were attaching the olfactory nerve (p = 0.011). Our results suggested that fibrin-gelatin fixation method can reduce the reported risk of anosmia. However, the possibility of olfactory nerve damage is relatively high when operating on brain tumors attaching olfactory nerve.

Superficial temporal artery to proximal posterior cerebral artery bypass through the anterior temporal approach

Background:

The superficial temporal artery (STA) to proximal posterior cerebral artery (PCA) (P2 segment) bypass is one of the most difficult procedures to perform because the proximal PCA is located deep and high within the ambient cistern. STA to proximal PCA bypass is usually performed through a subtemporal approach or posterior transpetrosal approach, and rarely through a transsylvian approach. The aim of this study was to describe the operative technique of STA to proximal PCA bypass through a modified transsylvian approach (anterior temporal approach).

Methods:

STA to proximal PCA bypass was performed through an anterior temporal approach in three patients with intracranial aneurysm. We describe the details of the surgical technique.

Results:

The STA was successfully anastomosed to the proximal PCA in all cases. One patient suffered hemiparesis and aphasia due to infarction in the anterior thalamoperforating artery territory.

Conclusions:

STA to proximal PCA bypass can be performed through an anterior temporal approach in selected patients. We recommend that every precaution, including complete hemostasis, placement of cellulose sponges beneath the recipient artery to elevate the site of the anastomosis, and placement of a continuous drainage tube at the bottom of the operative field to avoid blood contamination during the anastomosis, should be taken to shorten the temporary occlusion time.

The frequency of postoperative stroke in moyamoya disease following combined revascularization: a single-university series and systematic review

Object

Although combined direct and indirect anastomosis in patients with moyamoya disease immediately increases cerebral blood flow, the surgical procedure is more complex. Data pertinent to the postoperative complications associated with combined bypass are relatively scarce compared with those associated with indirect bypass. This study investigated the incidence and characteristics of postoperative stroke in combined bypass and compared them with those determined from a literature review to obtain data from a large population.

Methods

A total of 358 revascularization procedures in 236 patients were retrospectively assessed by reviewing clinical charts and radiological data. PubMed was searched for published studies on surgical treatment to determine the incidence of postoperative complications in a larger population.

Results

Seventeen instances of postoperative stroke were observed in 16 patients (4.7% per surgery, 95% CI 2.8%–7.5%). Postoperative stroke was more frequent (7.9% per surgery) in adults than in pediatric patients (1.7% per surgery, OR 4.07, 95% CI 1.12–14.7; p < 0.05). Acute progression of stenoocclusive changes were identified in the major cerebral arteries (anterior cerebral artery, n = 3; middle cerebral artery, n = 1; posterior cerebral artery, n = 2). The postoperative stroke rate was comparable with that (5.4%) determined from a literature search that included studies reporting more than 2000 direct/combined procedures. No differences in the stroke rates between the direct/combined and indirect procedures were found. In the literature review, direct/combined bypass was more often associated with excellent revascularization (angiographic opacification greater than two-thirds) than indirect bypass (p < 0.05).

Conclusions

This experience of 358 consecutive procedures is one of the largest series for which the postoperative stoke rate for direct/combined bypass performed with a unified strategy has been reported. A systematic review confirmed that the postoperative stroke rate for the direct/combined procedure was comparable to that for the indirect procedure.

Impact of cervical internal carotid clamping and radial artery graft bypass on cortical arterial perfusion pressure during craniotomy

Strategic cervical internal carotid occlusion is employed either temporarily or permanently in various neurosurgical procedures. The aim of the present study was to assess changes in cortical arterial pressure during cervical internal carotid cross-clamping before and after the placement of radial artery (RA) graft bypass in the treatment of complex carotid artery aneurysms. Perfusion pressure of the middle cerebral artery (MCA) was assessed in 22 patients with complex carotid aneurysm treated with RA graft bypass. Regional cerebral blood flow was assessed postoperatively using single-photon computed tomography. Mean cortical blood pressure (mcBP) was found to be 48.2 ± 24.2 and 97.0 ± 24.0 % of baseline after clamping the cervical internal carotid artery and opening the RA graft bypass, respectively. Cerebral perfusion pressure estimated by the mcBP failed to sustain a critical limit of greater than 70 mmHg under craniotomy in 16 out of 20 (80 %) patients. There was an inverse correlation in mcBP between the baseline and after the placement of the RA graft bypass (r = 0.66, P < 0.005). Postoperative regional cerebral blood flow in the MCA territory on the ipsilateral side of the aneurysm was 97 ± 7 % of that of the contralateral side after internal carotid artery (ICA) ligation combined with RA graft bypass. Substantial pressure reductions in cerebral cortical arteries were observed during the cervical internal carotid cross-clamping. Perfusion pressure in peripheral cortical arteries after the placement of the RA graft bypass was comparable to the state before ICA clamping.

Usefulness of V3-radial artery graft-V4 bypass in bilateral fusiform aneurysms of vertebral artery: case report

A 55-year-old woman with bilateral vertebral artery (VA) aneurysms was transferred to our hospital. She suffered from a minor stroke. Magnetic resonance imaging (MRI) for the stroke incidentally revealed bilateral VA aneurysms. Due to its size, more observation was recommended, and the patient was found eager to be treated. Both side surgeries were found inappropriate because of severe lower cranial nerve disturbances. The right aneurysm involved the posterior inferior cerebellar artery (PICA) and the V4 segment was deviated to the right side. Therefore, the smaller right aneurysm was treated first with an occipital artery (OA)-PICA bypass and a V3-radial artery graft (RAG)-V4 bypass followed by proximal clipping of the PICA and the right VA. The right VA was successfully remade by RAG and the right aneurysm was not revealed on postoperative examination. By doing so, the opposite aneurysm was able to be eliminated by the parent artery occlusion even by using an interventional radiology (IVR). The V3-RAG-V4 bypass is a useful method for treating bilateral VA aneurysms. This is a new bypass which has not been reported so far to the best of our knowledge.

The Anterior Temporal Approach for Microsurgical Thromboembolectomy of an Acute Proximal Posterior Cerebral Artery Occlusion

BACKGROUND:

In a short window of time, intravenous and intra-arterial thrombolysis is the first treatment option for patients with an acute ischemic stroke caused by the occlusion of one of the major brain vessels. Endovascular treatment techniques provide additional treatment options. In selected cases, high revascularization rates following microsurgical thromboembolectomy in the anterior circulation were reported. A technical note on successful thromboembolectomy of the proximal posterior cerebral artery has not yet been published.

OBJECTIVE:

To describe the technique of microsurgical thromboembolectomy of an acute proximal posterior cerebral artery occlusion and the brainstem perforators via the anterior temporal approach.

METHODS:

The authors present a technical report of a successful thromboembolectomy in the proximal posterior cerebral artery. The 64-year-old male patient had an acute partial P1 thromboembolic occlusion, with contraindications for intravenous recombinant tissue plasminogen activator. The patient underwent an urgent microsurgical thromboembolectomy after a frontotemporal craniotomy.

RESULTS:

The postoperative computerized tomography angiography showed complete recanalization of the P1 segment and its perforators, which were previously occluded. The early outcome after 1 month and 1 year follow-ups showed improvement from modified Rankin scale 4 to modified Rankin scale 1.

CONCLUSION:

Microsurgical thromboembolectomy can be an effective treatment option for proximal occlusion of the posterior cerebral artery in selected cases and experienced hands. Compared with endovascular treatment, direct visual control of brainstem perforators is possible.

The significance of intraoperative monitoring of muscle motor evoked potentials during unruptured large and giant cerebral aneurysm surgery

The goal of this study was to characterize the utility of muscle motor evoked potentials (MMEPs) elicited by direct cortical stimulation as a means of monitoring during unruptured large and giant cerebral aneurysm surgery. This analysis focused on intraoperative changes in MMEPs and their relationship to postoperative motor function. The study population consisted of 50 patients who underwent surgery for large (n = 31) or giant (n = 19) cerebral aneurysms. Intraoperative MMEPs were continuously and successfully obtained in muscles belonging to the vascular territory of interest. There was no postoperative motor paresis in 31 (62%) patients in whom intraoperative MMEPs remained unchanged. Transient MMEP change occurred in 15 (30%) of the 50 patients, but 9 of those patients had no postoperative motor deficits, 5 had transient motor deficits, and 1 suffered permanent motor deficits resulting from postoperative delayed blood flow insufficiency due to arteriosclerosis of the parent artery. Permanent MMEP loss occurred in 4 (8%) of 50 patients, all of whom developed severe and permanent postoperative motor deficits. MMEP is a useful monitoring modality in patients undergoing surgery for large or giant cerebral aneurysms. This strategy can help predict functional prognosis or guide the neurosurgeon intraoperatively in an effort to promote better outcomes.

Discrepancy between preoperative imaging and postoperative pathological finding of ruptured intracranial dissecting aneurysm, and its surgical treatment: case report

The choice of therapeutic strategy for intracranial dissecting aneurysm is often based on radiographic features, including characteristic geometry (e.g., irregular stenosis, segmental stenosis, aneurysm formation [pearl-and-string sign]), irregular fusiform or aneurysmal dilation, double lumen, and tapering occlusion. However, there is often a discrepancy between preoperative radiographic data and actual dissecting length. The present report describes three cases in which there was a discrepancy between preoperative radiographic data and actual dissecting length in patients undergoing direct trapping with or without revascularization. All three cases experienced good outcomes, but these cases underscore the fact that open surgery is a good option for management of ruptured intracranial dissecting aneurysms for determination of the rupture point, dissecting length, and the relationship between dissecting area and small arteries arising from the associated vessel.

Posttraumatic carotid-cavernous fistulae treated by internal carotid artery trapping and high-flow bypass using a radial artery graft--two case reports

Two patients presented with post-traumatic carotid-cavernous sinus fistulae (CCFs) that were successfully treated by high-flow bypass using a radial artery graft after initial unsuccessful attempts at obliteration by intravascular embolization. Case 1 was a 20-year-old man with a CCF detected by magnetic resonance imaging and angiography following an accident. Although the CCF appeared partially occluded by intravascular embolization, serial angiography revealed CCF recurrence. The CCF was trapped by placing a high-flow bypass. Case 2 was a 21-year-old man who presented with bilateral CCFs after sustaining face trauma. The bilateral CCFs were directly treated because of recurrence after balloon occlusion. At present, intravascular surgery is the first treatment choice, but placing a high-flow bypass with trapping of the CCF gained time to treat the CCF and may be useful for treating post-traumatic CCF that cannot be effectively eliminated by intravascular techniques.

Changing Treatment Strategy From Clipping to Radial Artery Graft Bypass and Parent Artery Sacrifice in Patients With Ruptured Blister-Like Internal Carotid Artery Aneurysms

BACKGROUND:

Blood blister-like aneurysms (BBAs) are aneurysms with ill-defined fragile necks arising from an internal carotid artery (ICA) and associated with high mortality.

OBJECTIVE:

To describe strategies and outcomes in patients in whom radial artery (RA) graft bypass with ICA sacrifice was considered as the primary treatment during the acute phase of subarachnoid hemorrhage.

METHODS:

The authors analyzed the clinical records of 20 patients who were treated between 2004 and 2011 at their hospital and affiliate institutions.

RESULTS:

A majority of the patients were treated during the acute phase (&lt;24 hours, n = 15). A favorable outcome was achieved in 18 (90%) patients. The treatment strategies used were as follows: (1) ICA trapping/external carotid artery (ECA)-RA-middle cerebral artery (MCA) bypass (n = 13), (2) ICA trapping/superficial temporal artery-MCA bypass (n = 2), (3) aneurysm clipping with RA-MCA temporary bypass (n = 3), (3) aneurysm clipping with proximal ICA ligation and ECA-RA-MCA bypass (n = 1), and (4) direct clipping (n = 1). Postoperative infarction was observed in 6 patients and was ascribed to vasospasm (n = 1), retrograde thrombosis associated with trapping (n = 2), and reasons unrelated to the surgical procedures (n = 3).

CONCLUSION:

Trapping with RA graft bypass demonstrated favorable results in patients with internal carotid BBAs. Although trapping/RA graft bypass is a definitive treatment for BBAs located proximal to the origin of the posterior communicating artery, some distal BBAs preclude ICA trapping to spare the perforating arteries.

Stability of the Fullerenes Thin Film Deposited on the SI(100) Surface

We have performed a constant temperature classical molecular dynamics simulation of the epitaxial growth of a C60 monolayer film deposited on the dimerized Si(100) surface. Our simulation, based on non-central many-body inter-atomic potentials, is capable of predicting the structural stability of the C60 film and the Si substrate and provides a theoretical basis for the results of a recently-performed STM- based experiment for this system.

Three-dimensional geometries have been generated on computer and used for the animation of the simulation runs.

Laparoscopic adrenalectomy by general surgeons familiar with laparoscopic surgical skills: experiences of a single center

INTRODUCTION

Laparoscopic adrenalectomy (LA) is still considered an advanced procedure requiring a high level of skills with potentially lethal pitfalls. We report our clinical outcomes of 50 cases of LA, and discuss whether a general surgeon is suitable to perform LA, and the effect of mentor-initiated training on improving outcomes.

METHODS

Patients' age and sex, size of tumor, preoperative diagnosis, procedure details, intra- and postoperative complications, operation time, final histological diagnosis, and length of stay of 50 consecutive cases of LA were collected through a review of hospital charts. These cases were divided into two equal consecutive groups. The first 25 cases were named Group A, and the latter 25 cases were named Group B, and two groups were compared.

RESULTS

Median operation time in Group B (110 min) was significantly shorter than that in Group A (125 min) (P=0.021). Mean postoperative hospital stay in Group B (7.0 ± 2.8 days) was significantly shorter than that in Group A (10.9 ± 8.8 days) (P=0.019). Only one case (Group B) of 50 LA (2%) required a conversion to open adrenalectomy because of failure to control bleeding during dissection.

CONCLUSION

Under mentor-initiated training, general surgeons with experience of more than 50 cases of laparoscopic cholecystectomies can attain favorable clinical outcomes in LA.

Large aneurysm in a nonbifurcating cervical carotid artery: an aneurysm associated with a rare anomaly treated with radial artery graft bypass: case report

BACKGROUND AND IMPORTANCE

A nonbifurcating cervical carotid artery is an extremely rare type of carotid artery anomaly. We present a patient with a nonbifurcating cervical carotid artery and a large aneurysm of the cavernous internal carotid artery (ICA). The patient was successfully treated with combined microsurgical and endovascular techniques. We describe this case with reference to the relevant literature.

CLINICAL PRESENTATION

A 66-year-old woman with progressive left external ocular movement dysfunction was found to have a large left cavernous ICA aneurysm. Serial magnetic resonance angiography revealed progressive growth of the lesion. In addition, conventional angiography showed a nonbifurcating cervical carotid artery and a persistent primitive trigeminal artery. The aneurysm was found unsuitable for direct surgery because of its size and location and for endovascular intervention because of extreme tortuosity of both carotid and right vertebral arteries. Surgery was performed in 2 stages. First, we performed an extracranial-intracranial high-flow bypass using radial artery graft, followed by proximal occlusion of the carotid artery. As the second stage, the patient underwent intravascular parent artery occlusion via the radial artery graft bypass to approach the intracranial carotid artery. The carotid artery was successfully coil embolized, and the aneurysm was undetectable on a postprocedure angiogram. Serial follow-up magnetic resonance imaging revealed thrombosis of the aneurysm.

CONCLUSION

We report a rare case that involves the novel use of the radial artery graft bypass as an approach for parent vessel occlusion.

Mechanisms underlying ketamine-induced synaptic depression in rat hippocampus-medial prefrontal cortex pathway

The non-competitive N-methyl-D-aspartate NMDA receptor antagonist ketamine, a dissociative anesthetic capable of inducing analgesia, is known to have psychotomimetic actions, but the detailed mechanisms remain unclear because of its complex properties. The present study elucidated neural mechanisms of the effect of ketamine, at doses that exert psychotomimetic effects without anesthetic and analgesic effects, by evaluating cortical synaptic responses in vivo. Systemic administration (i.p.) of low (1 and 5 mg/kg), subanesthetic (25 mg/kg) and anesthetic (100 mg/kg) doses of ketamine dose-dependently decreased hippocampal stimulation-evoked potential in the medial prefrontal cortex (mPFC) in freely moving rats. The behavioral analysis assessed by prepulse inhibition (PPI) of acoustic startle response showed that ketamine (5 and 25 mg/kg, i.p.) produced PPI deficit. Thus, the psychotomimetic effects observed in ketamine-treated groups (5 and 25 mg/kg, i.p.) are associated with the induction of synaptic depression in the hippocampus-mPFC neural pathway. Based on these results, we further examined the underlying mechanisms of the ketamine-induced synaptic depression under anesthesia. Ketamine (5 and 25 mg/kg, i.p.) caused increases in dialysate dopamine in the mPFC in anesthetized rats. Moreover, the ketamine-induced decreases in the evoked potential, at the dose 5 mg/kg which has no anesthetic and analgesic effects, were indeed absent in dopamine-lesioned rats pretreated with 6-hydroxydopamine (6-OHDA; 150 μg/rat, i.c.v.). Ketamine (5 mg/kg, i.p.)-induced synaptic depression was blocked by pretreatment with dopamine D1 receptor antagonist SCH 23390 (10 μg/rat, i.c.v.) but not dopamine D2 receptor antagonist haloperidol (1.5 mg/kg, i.p.), suggesting that dopaminergic modulation mediated via D1 receptors are involved in the synaptic effects of ketamine. Furthermore, ketamine (5 mg/kg, i.p.)-induced synaptic depression was prevented also by GABAA receptor antagonist bicuculline (0.2 or 2 μg/rat, i.c.v.). These findings suggest that ketamine at the dose that exerts psychotomimetic symptoms depresses hippocampus-mPFC synaptic transmission through mechanisms involving dopaminergic modulation mediated via D1 receptors, which may lead to a net augmentation of synaptic inhibition mediated via GABAA receptors.

"Bonnet" bypass to proximal trunk of middle cerebral artery with a radial artery interposition graft: technical note

BACKGROUND

Anastomosis of the superficial temporal artery (STA) to the middle cerebral artery (MCA) is useful for treating certain patients with internal carotid artery occlusion or MCA occlusion. However, in the case of common carotid artery (CCA) occlusion, since the blood flow in the STA is insufficient, another artery should be used as the donor artery. The cortical branches of the MCA are usually selected as recipients in the STA-MCA bypass. However, the intracranial vascular filling gradually increases over a few months after conventional cortical MCA bypass grafting, while early or even immediate vascular filling is observed after proximal MCA bypass grafting. This study aims to develop an elongation technique of the contralateral STA to reach the proximal segment of the ipsilateral MCA.

METHODS

Anastomosis of the contralateral STA to the secondary trunk of the ipsilateral MCA was performed in 2 patients with occlusion of the CCA and ipsilateral vertebral artery (VA). The contralateral STA was extended with a radial artery (RA) graft in order to supply blood to the ischemic area. Elongation of the STA by using an RA interposition graft sufficiently lengthens the graft to enable its anastomosis with the contralateral M2 segment. Postoperative imaging revealed good bypass patency even at 1 year after the surgery.

CONCLUSION

This novel technique of performing the "bonnet" bypass was effective in treating both CCA and ipsilateral VA occlusion; moreover, this procedure of elongation of the STA can increase candidates of the recipient, and enables one to perform a double bypass to the anterior cerebral artery (ACA) or posterior cerebral artery (PCA).

A surgical case of delayed coil migration after balloon-assisted embolization of an intracranial broad-neck aneurysm: case report

BACKGROUND AND IMPORTANCE

Balloon-assisted coil placement is an important technique for coil embolization of broad-neck aneurysms. With this technique, we can prevent coil migration into a parent artery during a procedure. Complications of intraprocedural coil migration have been reported in the literature. However, delayed coil migration is extremely rare. We present a case of delayed coil migration after balloon-assisted coil embolization and describe our management of this complication.

CLINICAL PRESENTATION

A 59-year-old man presented with hypertension and a tension headache. Clinical evaluation incidentally discovered an unruptured broad-neck aneurysm at the left internal carotid bifurcation. Endovascular embolization of the aneurysm was performed with a balloon-assisted technique. The patient had a transient ischemic attack, and a skull radiograph showed coil migration 3 months after the procedure. We performed an operation to remove the coils and to clip the aneurysm with superficial temporal artery and middle cerebral artery bypass. The patient was discharged without neurological deficit.

CONCLUSION

This is a rare case in which delayed coil migration into the parent artery occurred after balloon-assisted coil embolization, highlighting the importance of surgical management of delayed coil migration.

Dural cavernous hemangioma of the cerebellar falx

A 47-year-old man presented with a rare case of dural cavernous hemangioma of the cerebellar falx incidentally detected as a mass lesion in the posterior cranial fossa. Neurological examination revealed no deficits or physical symptoms. Computed tomography demonstrated a well-demarcated hyperdense mass, with no calcification, in the cerebellar vallecula. Magnetic resonance imaging showed the extra-axial mass as homogeneously isointense on T(1)-weighted images, and hyperintense on T(2)-weighted images, compared to the adjacent cerebellar parenchyma that had no hypointense halo. The cerebellar vermis was slightly compressed ventrally, the adjacent brain parenchyma was not swollen, and there was no evidence of hydrocephalus. The mass and the attached cerebellar falx were homogeneously enhanced by contrast medium. The dural enhancement was considered a dural tail. No other intracranial vascular malformations were found. The preoperative diagnosis was posterior cranial fossa meningioma attached to the cerebellar falx. Median suboccipital craniotomy exposed the reddish mass attached to the cerebellar falx. The arachnoid plane was well preserved. Total en bloc resection was performed with minimal blood loss. The postoperative course was unremarkable. The resected mass had a reddish-brown mulberry appearance, with spongy cross section with multiple blood-filled spaces. Histological examination identified dilated blood-containing channels lined with flattened endothelium and separated by fibrous tissue, but no luminal thrombus or hemorrhage. The histological diagnosis was dural cavernous hemangioma of the cerebellar falx. Preoperative radiosurgery or embolization is recommended for most of the dural cavernous hemangiomas, but surgery for the present dural cavernous hemangioma of the cerebellar falx was performed safely.

Promoter hypermethylation of tumor-related genes in sporadic colorectal cancer in young patients

Sporadic colorectal cancer (SCRC) occurring in young patients represent a subset with a higher proportion of advanced tumors and a poor prognosis, however, the genetic basis of SCRCs has not yet been sufficiently studied. We assigned 16 SCRC patients aged 40 years or less to group 1, and 30 SCRCs patients aged 65 years or more to group 2. The methylation status in the promoter of 7 tumor suppressor genes regarding these two groups was then examined. The average number of hypermethylated tumor-related genes per sample in group 1 was 1.50 +/- 0.07, which was significantly lower than that in group 2 of 2.73 +/- 1.24 (p = 0.0040). The frequencies of the promoter hypermethylation of hMLH1, p15INK4b, p16INK4a, and RASSF1A in group 1 were 12.5%, 12.5%, 12.5%, 6.3%, and 0.0%, which were substantially less frequent than those same rates observed in group 2. In contrast, the frequencies of the promoter hypermethylation of APC, MGMT, p14ARF, in group 1 were 43.8%, 37.5%, and 31.3%, which were as frequent as those seen in group 2. The promoter hypermethylation of APC, MGMT, and pl4ARF is therefore considered to be closely related to the development of SCRCs in young patients, regardless of aging.

Characterization of R peptide of murine leukemia virus envelope glycoproteins in syncytium formation and entry

The C-terminal R peptide of ecotropic murine leukemia virus (MLV) envelope protein (Env) negatively controls membrane fusion activity. The R peptide cleavage during virion maturation activates its fusogenicity and is required for viral entry. We analyzed fusogenicity and transduction efficiency of mutant Env proteins of ecotropic, amphotropic, polytropic, and xenotropic MLVs. As the result, we found that the hydrophobic amino acid residues around the R peptide cleavage site are important for membrane fusion inhibition by the R peptide. In addition, we found that Env complexes with R peptide-truncated and -containing Env proteins have lower fusogenicity and transduction efficiency than those with the R-peptide-truncated Env alone, suggesting that efficient R peptide cleavage is required for efficient MLV vector transduction. The role of R peptide cleavage in amphotropic, polytropic, and xenotropic MLV infection has not been investigated. We found in this study that the R peptide cleavage is required for amphotropic, xenotropic, and polytropic MLV vector transduction, like with ecotropic MLV. The R-peptide-truncated Env proteins of the xenotropic and polytropic MLVs, however, had much lower fusogenicity than those of the ecotropic and amphotropic MLVs. These results provide valuable information for construction of efficient MLV vectors and for understanding the retroviral entry mechanism.

Urgent simultaneous revascularization of the carotid artery and ascending aortic replacement for type A acute aortic dissection with cerebral malperfusion

We report a case of successful urgent surgical therapy for a Stanford type A acute aortic dissection with cerebral malperfusion. A woman with a sudden severe chest pain consulted the emergency department. Computed tomography results showed a Stanford type A acute aortic dissection. She had repeating left paralysis, so a cerebrovascular study was performed. It showed that the collateral left carotid and vertebral arteries perfused only the right cerebral hemisphere. Hence, it was thought that the left paralysis was caused by cerebral malperfusion due to the dissection. Simple aortic replacement endangered the right cerebral hemisphere, so we performed urgent revascularization of the right carotid artery, followed by an ascending aortic replacement procedure.

Analysis of the relationship between sex and chromosomal aberrations in colorectal cancer by comparative genomic hybridization

Colorectal cancer is thought to be more common in men than in women. The chromosomal locations of DNA gains and losses in surgical specimens of colorectal tumours were detected by comparative genomic hybridization and were compared by gender. Five chromosomal regions, 7p, 8p, 8q, Xp and Xq, contained multiple gains that were significantly more common in males than in females, and within these regions, the differences were significant for Xp21, Xp11.3, Xp11.4 and Xq26. Regions 1p, 3q, 11q, 12p, 12q and 15q contained multiple sites of gain that were significantly more common in females than in males. Tumours from male and female patients showed significantly more losses at 11p and 15q, and at 4q and Xq, respectively. The fact that gains in X-chromosomal regions were detected with a significantly higher frequency in tumours from male patients suggests that the difference between the genders might be explained by X-chromosomal inactivation.

Wavelength-Sensitive Photocatalytic Degradation of Methyl Orange in Aqueous Suspension over Iron(III)-doped TiO2Nanopowders under UV and Visible Light Irradiation

Well-crystallized iron(III)-doped TiO2 nanopowders with controlled Fe3+ doping concentration and uniform dopant distribution, have been synthesized with plasma oxidative pyrolysis. The photocatalytic reactivity of the synthesized TiO2 nanopowders with a mean particle size of 50-70 nm was quantified in terms of the degradation rates of methyl orange (MO) in aqueous TiO2 suspension under UV (mainly 365 and 316 nm) and visible light irradiation (mainly 405 and 436 nm). The photodecomposition of MO over TiO2 nanopowders followed a distinct two-stage pseudo first order kinetics. Interestingly, the photocatalytic reactivity depends not only on the iron doping concentration but also on the wavelength of the irradiating light. Under UV irradiation, nominally undoped TiO2 had much higher reactivity than Fe3+ -doped TiO2, suggesting that Fe3+ doping (> 0.05 at. %) in TiO2 with a mean particle size of approximately 60 nm was detrimental to the photocatalytic decomposition of methyl orange. Whereas, under visible light irradiation, the Fe3+ -doped TiO2 with an intermediate iron doping concentration of approximately 1 at. % had the highest photocatalytic reactivity due to the narrowing of band gap so that it could effectively absorb the light with longer wavelength. A strategy for improving the photocatalytic reactivity of Fe3+ -doped TiO2 used in the visible light region is also proposed.

Giant intracranial aneurysm of the anterior communicating artery treated by direct surgery using A3-A3 side-to-side anastomosis and A3-RA graft-STA anastomosis

We describe a giant aneurysm of the anterior communicating artery (ACoA) which was treated with a STA-RA graft-A3 bonnet bypass and A3-A3 side-to-side anastomosis. A giant and partially thrombosed ACoA aneurysm was partially coated 3 years before his current presentation, its gradual increase producing visual field disturbances. An A3-A3 side-to-side anastomosis and STA-RA graft-A3 bonnet bypass were performed. The aneurysm was dissected, and the thrombus removed under transient parent-artery occlusion. The aneurysmal neck was successfully clipped without encountering ischemic changes. This strategy may be useful for treating giant or thrombosed aneurysms in the region of the ACoA.

Clinical Study of Cerebrospinal Fluid Dynamics Using 111In-DTPA SPECT in Patients With Subarachnoid Hemorrhage

The ventricle-to-background ratio and clearance rate constant measured by indium-111 diethylenetriaminepenta-acetic acid single photon emission computed tomography ((111)In-DTPA SPECT) were evaluated for predicting hydrocephalus in 16 patients at 2 to 3 weeks after onset of subarachnoid hemorrhage. The activity in the lateral ventricles, basal cistern, and hemispheric convexities was measured at 6, 24, and 48 hours after lumbar injection of radionuclide. In the follow-up study, eight patients developed hydrocephalus, and required ventriculoperitoneal shunting. Radioactivity measured in the hemispheric convexity did not reach peak activity within 48 hours. The clearance rate measured by applying the mono-exponential equation failed to show delayed clearance of radionuclide in hydrocephalus. The ratio between the ventricle and basal cistern measured at 6 hours postinjection was the best predictor of hydrocephalus (F(1, 30) = 42.84, p < 0.0001). These results suggest that a single (111)In-DTPA SPECT scan may be sufficient to identify patients at risk of developing hydrocephalus.

Reference Table Predicting the Outcome of Subarachnoid Hemorrhage in the Elderly, Stratified by Age

Although the recovery from an aneurysmal subarachnoid hemorrhage (SAH) is hampered by advanced age, the impact of age on surgical outcome has not been evaluated quantitatively. We studied 168 patients with SAH treated between 2000 and 2002. Study variables included sex, age, location of aneurysm, preoperative Glasgow coma scale (GCS) score, and presence of intracerebral hematoma, vasospasm, or hydrocephalus. Univariate and multiple logistic regression analyses were applied to test the effect of age and preoperative GCS scores on the likelihood of a favorable outcome. Multivariate logistic regression analysis showed that advanced age (odds ratio [OR] = 1.109; 95% confidence interval [CI] = 1.051-1.169) and decrements of preoperative GCS score (OR = 0.69; 95% CI = 0.586-0.812) were inversely associated with the likelihood of a favorable outcome. Based on the results, we generated a reference table that depicts the outcome based on the preoperative GCS score stratified by age. This simple reference table is useful in predicting surgical outcome in emergent situations. This study indicated that a 10-year advance in age is equivalent to a 2.3-point reduction in the GCS score.

Simultaneous Superficial Temporal Artery to Middle Cerebral or Anterior Cerebral Artery Bypass With Pan-synangiosis for Moyamoya Disease Covering Both Anterior and Middle Cerebral Artery Territories-Technical Note-

Some patients with moyamoya disease treated by conventional surgical procedures may develop postoperative refractory ischemia and perioperative cerebral infarction in the anterior cerebral artery (ACA) territory. We present a novel operative procedure for moyamoya disease to avoid the risk of ischemia in the ACA territory, which consists of simultaneous superficial temporal artery (STA) to middle cerebral artery (MCA) or ACA bypass with pan-synangiosis, encephalo-duro-arterio-myo-synangiosis for the lateral frontal and temporal areas, and encephalo-galeo-arterio-synangiosis for the medial frontal area. This procedure can establish direct bypass to the ACA territory at the first intervention. Simultaneous STA-MCA and STA-ACA bypasses with pan-synangiosis is suitable for patients with moyamoya disease associated with severely impaired perfusion of the ACA territory requiring direct bypass surgery.

Herpes simplex virus 1 recombinant virions exhibiting the amino terminal fragment of urokinase-type plasminogen activator can enter cells via the cognate receptor

Earlier this laboratory constructed a herpes simplex virus 1 recombinant (R5111) that carries a IL13 ligand inserted into glycoprotein D and can enter cells via the IL13Ralpha2 receptor commonly expressed on the surface of malignant glioma cells. In this report, we describe the properties of two recombinant viruses carrying chiemric gD genes. In R5181 recombinant virus the chimeric gene consisted on the residues 20-155 of urokinase plaminogen activator (uPA) inserted between residues 24 and 25 of gD. In R5182 the insert consisted of a 23-residue sequence encoding the uPA binding domain for the urokinase plaminogen activator receptor (uPAR). These viruses were constructed for three reasons, to increase the number of viruses that specifically target receptors on the surface of malignant glioma cells, to determine whether viruses exhibiting novel ligands could enter cells via receptors anchored to the cell surface via glycosylphosphatidylinositol anchor as has been recently demonstrated for nectin1, and to determine whether receptors other than IL13Ralpha2 could be targeted by genetic engineering of the virus. We report that R5181 but not R5182 recombinant virus was able to enter cells expressing uPAR. The results indicate that HSV-1 recombinant viruses can be engineered to enter cells via a variety of unrelated nonviral receptors, including receptors that are anchored to the cells surface but without transmembrane domains.

Pyrogenic Iron(III)-Doped TiO2 Nanopowders Synthesized in RF Thermal Plasma: Phase Formation, Defect Structure, Band Gap, and Magnetic Properties

Iron(III)-doped TiO(2) nanopowders, with controlled iron to titanium atomic ratios (R(Fe/Ti)) ranging from nominal 0 to 20%, were synthesized using oxidative pyrolysis of liquid-feed metallorganic precursors in a radiation-frequency (RF) thermal plasma. The valence of iron doped in the TiO(2), phase formation, defect structures, band gaps, and magnetic properties of the resultant nanopowders were systematically investigated using Mössbauer spectroscopy, XRD, Raman spectroscopy, TEM/HRTEM, UV-vis spectroscopy, and measurements of magnetic properties. The iron doped in TiO(2) was trivalent (3+) in a high-spin state as determined by the isomer shift and quadrupole splitting from the Mössbauer spectra. No other phases except anatase and rutile TiO(2) were identified in the resultant nanopowders. Interestingly, thermodynamically metastable anatase predominated in the undoped TiO(2) nanopowders, which can be explained from a kinetic point of view based on classical homogeneous nucleation theory. With iron doping, the formation of rutile was strongly promoted because rutile is more tolerant than anatase to the defects such as oxygen vacancies resulting from the substitution of Fe(3+) for Ti(4+) in TiO(2). The concentration of oxygen vacancies reached a maximum at R(Fe/Ti) = 2% above which excessive oxygen vacancies tended to concentrate. As a result of this concentration, an extended defect like crystallographic shear (CS) structure was established. With iron doping, red shift of the absorption edges occurred in addition to the d-d electron transition of iron in the visible light region. The as-prepared iron-doped TiO(2) nanopowders were paramagnetic in nature at room temperature.

Experience from "double-insurance bypass." Surgical results and additional techniques to achieve complex aneurysm surgery in a safer manner

BACKGROUND

"Double-insurance bypass" was recently advocated to avoid the risk of cerebral ischemia during prolonged temporary occlusion of the carotid artery. For large aneurysms needing temporary but prolonged obliteration of the internal carotid artery (ICA). We have attempted the double-insurance bypass in 15 patients and, herein, report the efficacies and limitations of the procedure, and surgical techniques to make this procedure safer.

METHODS

We treated 15 patients with complex internal carotid aneurysms by clipping surgery with the aid of radial artery (RA) to proximal middle cerebral artery (MCA) bypass, so-called double-insurance bypass. We analyzed surgical results of the procedure.

RESULTS

In 11 patients, the duration of temporary occlusion of the ICA could be prolonged for as long as 110 minutes (mean, 45 minutes) without any ischemic complications. One patient in the earlier period of our experience suffered extended cerebral infarction due to possible restricted blood flow through the RA, because the brachial artery was compressed by the firm shoulder joint and neighboring structures. Thereafter, we routinely monitored the blood pressure of MCA (MCABP) and never experienced such cortical infarctions. Another 3 patients, however, experienced ischemia in the territory of perforating arteries that originated from a segment that could not be perfused by the RA-MCA bypass.

CONCLUSIONS

In combination with monitoring of MCABP, the double-insurance bypass can be a safer and more potent adjunctive procedure for the treatment of complex internal carotid aneurysms which require prolonged temporary occlusion of the ICA.

Method for measuring sinus and vein pressure during surgery: technical note

BACKGROUND

Measurement of dural sinus or drainage vein pressure is useful for determining the appropriate treatment for some patients. We report a novel measurement procedure that reduces bleeding from the needle puncture site as well as further tearing of the wall.

METHODS

The vessel is punctured through the patch by gelatin sponge with fibrin sealant and a siliconized elastic needle is introduced. After obtaining the desired measurements, the needle is withdrawn through the fibrin sealant-bearing patch whose presence facilitates sealing of the puncture site. To further decrease the incidence of complications due to incomplete hemostasis, an additional identically prepared path is placed over the site.

RESULTS

We have used this method in several operations and have encountered no complications. Our method also makes it possible to safely approach the drainers of pial arteriovenous malformations.

CONCLUSIONS

Our method is easy and convenient and prevents the leakage of blood from the puncture site and further tearing of the venous wall.