Junta Moroi

Morbidity and mortality from surgical treatment of unruptured cerebral aneurysms at Research Institute for Brain and Blood Vessels-Akita.

OBJECTIVE:Although the necessity of craniotomy for an unruptured cerebral aneurysm (UCA) is controversial, surgery is warranted if surgical risks are less than the risks of natural history. In this study, we investigated the need for craniotomy for UCAs on the basis of surgical risk. METHODS:History of cerebrovascular disorders, aneurysm site and size, surgical complications, and clinical outcome were investigated in 368 patients (134 men, 234 women; ages 31–79 yr) who underwent craniotomy for treatment of UCA at our institute between 1993 and 2000. RESULTS:We investigated 549 aneurysms. The mean size was 6.0 mm. Sites affected were the anterior cerebral artery (101 aneurysms), internal carotid artery (224 aneurysms), middle cerebral artery (201 aneurysms), and vertebrobasilar artery (23 aneurysms). The most common previous cerebrovascular disorders were subarachnoid hemorrhage (58 patients, 15.8%) and cerebral infarction (41 patients, 11.1%). Eight patients experienced permanent neurological deficits, for a total morbidity of 2.2%. One patient died, for a total mortality of 0.3%. For UCAs less than 10 mm in size, the morbidity was 0.6% and the mortality was 0%. For UCAs greater than 10 mm in size, the morbidity was 6.1% and the mortality was 1.2%. For UCAs in the anterior cerebral artery or middle cerebral artery, the morbidity was 0.3%. Temporary deficits were more frequently observed in patients older than 70 years of age than in patients 70 years of age or less. CONCLUSION:Surgical treatment is a viable alternative for patients 70 years of age or less with UCAs less than 10 mm in size or UCAs located in the anterior cerebral artery or middle cerebral artery, because the surgical risk of treating such UCAs is sufficiently lower than the annual rupture rate of UCAs (2.3%) and the mental stress suffered by patients with untreated UCAs.

Analysis of cerebral perfusion and metabolism assessed with positron emission tomography before and after carotid artery stenting. Clinical article.

OBJECT The authors analyzed cerebral perfusion and metabolism in patients with internal carotid artery stenosis before and after carotid artery stenting (CAS). METHODS Sixteen patients with internal carotid artery stenosis (>70%) underwent PET scanning before CAS, 1-7 days after CAS, and 3-4 months after CAS to assess a variety of parameters related to cerebral perfusion and metabolism. RESULTS Cerebral blood flow at rest (CBFrest) significantly increased in the immediate postoperative stage before returning to normal levels over the long term; this trend was also recognized on the contralateral side. In contrast, there was gradual improvement in the rate of CBF variation on acetazolamide administration (% CBFaz). Cerebral perfusion pressure (CBF/cerebral blood volume) increased rapidly during the acute stage and decreased in the long term, and the oxygen extraction fraction decreased slightly during the acute stage before normalizing over the long term. The cerebral metabolic rate of oxygen (CMRO2) increased slightly after stenting over both the short and long term. The ratios of ipsilateral to contralateral values (asymmetry index) for CBFrest, % CBFaz, cerebral blood volume, oxygen extraction fraction, and CMRO2 tended to approach 1.0 over time. CONCLUSIONS Repeated PET scanning revealed improvements in CBF, perfusion pressure, and oxygen metabolism after CAS. In particular, the vascular reserve tended to improve gradually, while CBF, cerebral perfusion pressure, and CMRO2 increased rapidly and peaked soon after CAS. These results suggest that a large discrepancy between rapidly increased CBF, perfusion pressure, and a small increase in vascular reserve in the acute stage after CAS could cause hyperperfusion syndrome.

Quantitative cerebral perfusion assessment using microscope-integrated analysis of intraoperative indocyanine green fluorescence angiography versus positron emission tomography in superficial temporal artery to middle cerebral artery anastomosis

Background: Intraoperative qualitative indocyanine green (ICG) angiography has been used in cerebrovascular surgery. Hyperperfusion may lead to neurological complications after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. The purpose of this study is to quantitatively evaluate intraoperative cerebral perfusion using microscope-integrated dynamic ICG fluorescence analysis, and to assess whether this value predicts hyperperfusion syndrome (HPS) after STA-MCA anastomosis. Methods: Ten patients undergoing STA-MCA anastomosis due to unilateral major cerebral artery occlusive disease were included. Ten patients with normal cerebral perfusion served as controls. The ICG transit curve from six regions of interest (ROIs) on the cortex, corresponding to ROIs on positron emission tomography (PET) study, was recorded. Maximum intensity (IMAX), cerebral blood flow index (CBFi), rise time (RT), and time to peak (TTP) were evaluated. Results: RT/TTP, but not IMAX or CBFi, could differentiate between control and study subjects. RT/TTP correlated (|r| = 0.534-0.807; P < 0.01) with mean transit time (MTT)/MTT ratio in the ipsilateral to contralateral hemisphere by PET study. Bland–Altman analysis showed a wide limit of agreement between RT and MTT and between TTP and MTT. The ratio of RT before and after bypass procedures was significantly lower in patients with postoperative HPS than in patients without postoperative HPS (0.60 ± 0.032 and 0.80 ± 0.056, respectively; P = 0.017). The ratio of TTP was also significantly lower in patients with postoperative HPS than in patients without postoperative HPS (0.64 ± 0.081 and 0.85 ± 0.095, respectively; P = 0.017). Conclusions: Time-dependent intraoperative parameters from the ICG transit curve provide quantitative information regarding cerebral circulation time with quality and utility comparable to information obtained by PET. These parameters may help predict the occurrence of postoperative HPS.

Preliminary study on safe thresholds for temporary internal carotid artery occlusion in aneurysm surgery based on motor-evoked potential monitoring.

Background: The study aims were to clarify safe duration for temporary vessel occlusion of the internal carotid artery (ICA) during aneurysm surgery as exactly as possible. We examined safe time duration (STD), where brain tissue exposed to ischemia will never fall into even the ischemic penumbra using intraoperative motor-evoked potential (MEP). Methods: In 45 patients, temporary occlusion of the ICA was performed with MEP. We measured STD as the duration of temporary vessel occlusion during which MEP changes did not occur. To estimate average STD, we calculated the 95% confidence interval for the population mean from sample data for STD in patients with MEP changes and in patients without changes. Results: In the proximal-control group, 4 of 38 patients (10.5%) developed intraoperative MEP changes. In 4 patients, the time to MEP change (i.e. STD) was 6.0 ± 2.5 min. STD was 3.8 ± 1.6 min in the 34 patients without changes. The average STD was 4.0 ± 0.6 min. In the trap group (proximal and distal flow control), five of seven patients (60.0%) experienced intraoperative MEP changes (STD, 2.3 ± 1.0 min). All patients in the trap group who developed MEP changes showed involvement of the anterior choroidal artery (AchA) in the trapped segment. Average STD was 2.3 ± 1.1 min when trapping involving the AchA. Conclusions: Although the study is preliminary based on the limited number of the patients, the 95% upper confidence limit for average STD was 4.6 min when the ICA was occluded proximal to the aneurysm, 3.4 min when the ICA was trapped involving the AchA.

Pathologically confirmed cryptic vascular malformation as a cause of convexity subarachnoid hemorrhage: case report.

BACKGROUND AND IMPORTANCE We report a rare case of pathologically confirmed cryptic vascular malformation as a cause of primary convexity subarachnoid hemorrhage (SAH) of unknown etiology. CLINICAL PRESENTATION A 48-year-old woman presented with sudden severe headache. Localized right convexity SAH was observed on computed tomography (CT) scan, but the origin could not be detected despite extensive workup covering the entire head by using 3.0-Tesla magnetic resonance (MR) imaging with MR angiography and CT angiography combined with venous-phase imaging with a 320-detector row CT scanner. Subsequent digital subtraction angiography (DSA) performed 2.5 hours after admission failed to reveal any cause of SAH; however, a right frontoparietal avascular region was suspected to be due to a newly developed intracerebral hematoma. The lesion was simultaneously confirmed by angiographic cone-beam CT imaging. Because she remained neurologically intact, we decided to perform a follow-up study later with medical management. However, she developed left hemiparesis 3 hours after DSA. CT scan demonstrated progression of the hematoma, and her symptoms gradually worsened. Emergent surgical exploration along the SAH superficial to the postcentral sulcus and hematoma evacuation were performed, with favorable functional outcome. Pathological examination confirmed cryptic vascular malformation with several abnormally dilated arterioles within the subarachnoid space surrounded by a thick SAH clot. CONCLUSION It is important to consider the possibility of ruptured cryptic vascular malformation as a cause of nontraumatic nonaneurysmal convexity SAH when recurrent hemorrhage occurs despite thorough diagnostic workup, because surgical resection may be the only curative treatment option to eliminate the risk of rebleeding and disabling symptoms.

Recurrent intracranial germinoma with dissemination along the ventricular catheter: a case report

Most recurrences of intracranial pure germinoma occur at the primary site, ventricular wall or subarachnoid space. We report a rare case of intracranial germinoma that recurred along the shunt tube 17 years after prior ventriculoperitoneal shunt and radiotherapy. The recurrent tumor, verified histologically as a pure germinoma, involved the right frontal lobe along the ventricular catheter. In spite of subsequent surgery, radiation and chemotherapy, the tumor recurred repeatedly. Recurrence after such a long period highlights the necessity of long-term follow up for patients with germinoma. We also discuss possible causes of tumor dissemination along the ventricular catheter.

Ruptured de novo posterior communicating artery aneurysm associated with arteriosclerotic stenosis of the internal carotid artery at the supraclinoid portion

Background: Several de novo intracranial aneurysms have been described related to changes in hemodynamics after therapeutic occlusion of internal carotid artery (ICA); however, de novo aneurysms related to a supraclinoid arteriosclerotic stenosis of the ICA have not been described yet. Authors consider that it is important to bear in mind the possibility of developing an aneurysm in these special conditions. Case Description: The evolution of a 62-year-old patient with subarachnoid hemorrhage, intraparenchymal frontal hematoma with some atypical circumstances that were presented together as well as the treatment he received are shown in this report. We can see this patient suffered a right thalamic hemorrhage at the age of 51 years; this condition was associated to a severe atherosclerotic stenosis of right supraclinoid ICAy. A long term had elapsed since the diagnosis of the stenosis and the discovery of a ruptured ipsilateral de novo supraclinoid internal carotid artery-posterior communicating artery (ICA-PcomA) aneurysm. Conclusions: It seems like both conditions: the atherosclerotic supraclinoid ICA which tells of an Samano et at: Ruptured De Novo PcomA Aneurysm Associated with Arteriosclerotic Stenosis of Supraclinoid ICA. Altered vessel environment coupled to a long exposure time, hemodynamic changes, unbalance in the wall sheer stress could all of them lead to the development of the de novo aneurysm.

Timing of retreatment for patients with previously coiled or clipped intracranial aneurysms: Analysis of 156 patients with multiple treatments.

Background: Some patients require a second surgical intervention for recurrence of treated aneurysms, untreated aneurysms in patients with multiple lesions, or de novo aneurysm. This retrospective review of the data was undertaken to evaluate when retreatment is necessary after initial aneurysm treatment. Methods: Cerebral aneurysms in 1755 patients were treated via clipping or coiling between January 1995 and September 2012. Postoperative follow-up was performed at 6 months after treatment and was repeated every 12 months (or longer) after treatment using three-dimensional computed tomography angiography or magnetic resonance angiography. Results: A cumulative total of 156 patients (8.9%) (117 women, 39 men; mean age: 55.0 years; range: 25–79 years) needed retreatment for rupture or regrowth of aneurysm (n = 31; ruptured (R)/remaining unruptured (U), 26/5), formation of de novo aneurysm (n = 45; R/U, 23/22), known untreated aneurysm in patients with multiple lesions (n = 78; R/U, 5/73), and hemorrhage from undetected aneurysm (n = 2). The regrowth risk is higher after endovascular treatment than after craniotomy and clipping. Median time to retreatment was 187 months (range: 11–280 months) for regrowth, 165 months (range: 22–330 months) for de novo, and 24 months (range: 2.8–417 months) for known untreated aneurysm. Regrowth or known with subarachnoid hemorrhage were frequently treated within 2 years from initial treatment. Conclusions: Aneurysms with residua or untreated aneurysms in patients with multiple lesions carry a risk of bleeding during a relatively short period, whereas there is a small but significant risk of de novo formation and subsequent hemorrhage at over 10 years after previous treatment.

A case of falcine sinus dural arteriovenous fistula.

BACKGROUND AND IMPORTANCE The falcine sinus is an embryonic vessel that connects the superior and inferior sagittal sinuses and mostly closes after birth. Although some cases of persistent falcine sinus have been reported, dural arteriovenous fistula (dAVF) associated with the falcine sinus has not previously been reported. CLINICAL PRESENTATION A 60-year-old man presented with asymptomatic dAVFs on digital subtraction angiography. The dAVFs were fed mainly by the cortical branch of the left anterior cerebral artery and drained into the falcine sinus. Intraoperatively, all veins draining in a retrograde manner into cortical veins were obstructed. However, cortical venous reflux did not disappear before removal of the falx cerebri, including the falcine sinus and inferior sagittal sinus. In this case, we considered falcine sinus dAVF as equivalent to olfactory groove dAVF because the medial olfactory artery, in its role as a common feeding artery in olfactory groove dAVF, is a rudiment of the anterior cerebral artery as the main feeding artery in this case. Intraoperative findings and the surgical specimen revealed a small vessel network in the falx cerebri communicating with the falcine and inferior sagittal sinuses, which was considered to represent a falcine venous plexus, not a vessel anomaly. CONCLUSION Extensive removal of the falx cerebri including the falcine sinus or complete endovascular obliteration of the whole falcine sinus as early as possible represents an important strategy in the surgical treatment of falcine sinus dAVF.

Recanalization of a ruptured vertebral artery dissecting aneurysm after occlusion of the dilated segment only.

Background: Internal trapping in which the dissecting aneurysm is occluded represents reliable treatment to prevent rebleeding of ruptured vertebral artery (VA) dissecting aneurysms. Various methods of internal trapping are available, but which is most appropriate for preventing both recanalization of the VA and procedural complications is unclear. Case Description: A 61-year-old male presented with subarachnoid hemorrhage caused by rupture of a left VA dissecting aneurysm. Only the dilated segment of the aneurysm was occluded by coil embolization. Sixteen days after embolization, angiography showed recanalization of the treated left VA with blood supplying the dilated segment of the aneurysm, which showed morphological change between just proximal to the coil mesh and just distal to a coil, and antegrade blood flow through this part. Pathological examination showed that the rupture site that had appeared to be the most dilated area on angiography was located just above the orifice of the entrance. However, we think that this case of ruptured aneurysm had an entrance into a pseudolumen that existed proximal to the dilated segment, with antegrade recanalization occurring through the pseudolumen with morphological change because of insufficient coil obliteration of the entrance in the first therapy. Conclusions: This case suggests that occlusion of both the proximal and dilated segments of a VA dissecting aneurysm will prevent recanalization, by ensuring that any entrance to a pseudolumen of the aneurysm is completely closed. Careful follow-up after internal trapping is important, since antegrade recanalization via a pseudolumen may occur in the acute stage.