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Background: The use of the exoscope has been increasing in the field of neurosurgery, as it can set the visual axis freely, enabling the surgeon to operate in a comfortable posture. Although endoscope-assisted surgery for compensation of insufficient surgical field is useful under the microscope, we report that using an endoscope in exoscopic surgery is safer and more useful. Methods: The exoscope used was ORBEYE. All surgical procedures were performed exoscopically from the beginning of the surgery. When endoscopic observation was required during the operation, the endoscope was inserted under observation by an exoscope. The exoscopic screen was 4K-3D and endoscopic screen was 4K-2D, the operation was performed while observing both screens at the same time. The endoscope was held manually or by a mechanical holder. Results: Twenty-two cases, including 14 requiring microvascular decompression (MVD) and eight requiring tumor removal, were performed by endoscopic-assisted exoscopic surgery. The endoscope could be inserted safely because its relationship with the surrounding structure could be observed under the exoscope, and the operator could observe both screens without moving the head. Fourteen of 22 patients required additional endoscopic treatment. Satisfactory two-handed operation was performed in 13 cases. Symptomatology disappeared in all cases of MVD, and sufficient tumor resection was achieved. Conclusion: Exoscopic surgery provides excellent surgical view that is not inferior to conventional microsurgery. As a large space can be secured between the scope and the surgical field, it is safer and easier to manipulate the endoscope under the exoscope.

BACKGROUND The difference between coil-embolized ruptured and unruptured aneurysms with respect to intra-aneurysmal thrombus formation remains to be determined. OBJECTIVE We examined whether there was a difference between ruptured and unruptured coil-embolized aneurysms in the rate and timing of thrombus formation in the aneurysmal sac and discuss the effect of thrombus on the treatment outcome. METHODS We evaluated 209 aneurysms with an aneurysmal dome smaller than 10 mm and a neck size less than 4 mm. Of these, 91 (43.5%) were ruptured. We assessed intra-aneurysmal thrombus formation by the coil-packing ratio (CPR): the percentage of coil volume occupying the aneurysmal sac. The initial CPR was defined as the CPR at which contrast influx into the sac ceased and the final CPR as that at the end of the procedure. ΔCPR was calculated as the difference between initial and final CPRs. Embolized aneurysms were evaluated on follow-up angiograms. RESULTS The initial CPR was significantly lower in ruptured aneurysms (P < .01), and there was not a significant difference in the final CPR between ruptured and unruptured aneurysms (P = .05). ΔCPR was significantly higher in ruptured aneurysms (P < .01). The rate of aneurysmal recanalization was significantly higher in ruptured aneurysms (P < .05). The incidence of recanalization was high in ruptured aneurysms with low initial CPR and ΔCPR values. CONCLUSION In ruptured aneurysms, intra-aneurysmal thrombus formation tends to occur in the earlier stages of coil embolization. In some cases, thrombus formation may inhibit dense coil packing and result in recanalization.

The rates of hemodynamic depression (HD) and thromboembolism were compared in 95 carotid artery stenting (CAS) procedures performed in 87 patients with severe carotid artery stenosis using self-expandable braided Elgiloy stents (Wallstent) in 52 and slotted-tube Nitinol stents (Precise) in 43 procedures. The blood pressure, pulse rate, and neurological signs were recorded at short intervals during and after CAS. All patients underwent diffusion-weighted magnetic resonance imaging within 5 days after the procedure. The incidences of hypotension, bradycardia, and both were 17.9%, 3.2%, and 11.6%, respectively. The rate of postprocedural HD was 23.1% with Wallstent and 44.2% with Precise; the difference was significant (p = 0.025). No patient manifested major cardiovascular disease after CAS. Diffusion-weighted magnetic resonance imaging revealed thromboembolism after 26.9% and 34.9% of Wallstent and Precise stent placement procedures, respectively; the difference was not significant. The type of self-expandable stent placed may affect the risk of procedural HD in patients undergoing CAS. Postprocedural HD was resolved successfully by the administration of vasopressors and by withholding antihypertensive agents.

Changes in the cerebral blood flow (CBF) are important for planning postoperative care in patients treated by carotid artery stenting (CAS). The relationship between intraprocedural changes in the angiographic cerebral circulation time (CCT) and perioperative CBF changes were retrospectively studied in 49 CAS procedures performed in 46 patients with carotid artery stenosis. The CCT, defined as the interval between the timing of maximal opacification at the terminal portion of the internal carotid artery and at the cortical vein, was determined by referring to time-density curves of data obtained from routine intraprocedural digital subtraction angiography. The intraoperative change in CCT (Delta CCT) was calculated for each of the 49 procedures. CBF studies, using dynamic perfusion computed tomography, were performed 10-2 days before and 2-4 days after CAS. Perioperative changes in the ratio of the CBF in the territory of the middle cerebral artery on the affected side to CBF on the contralateral side (%CBF) were calculated by subtracting pre- from postoperative %CBF (Delta%CBF) and the correlation between Delta CCT and Delta%CBF was evaluated. Mean CCT was shortened by 1.1 seconds from 5.3 to 4.2 seconds after CAS. Mean %CBF increased by 11.9% from 91.8% to 103.7% after the procedure. Delta CCT and Delta%CBF showed a significant positive correlation (r = 0.61, p = 0.008). Intraprocedural changes in angiographic CCT are predictive of postoperative CBF in patients with CAS.

We evaluate the efficacy of the coil embolization for tiny ruptured anterior communicating artery (ACoA) aneurysms. Of 21 ruptured ACoA aneurysms with a maximum diameter of 3 mm, coil embolization was successfully carried out in 20 (95%) as the first treatment option. Complete occlusion was achieved in 17 of 20 patients and nearly complete occlusion was realized in 3. There were no treatment-related complications. Seventeen of 20 patients were followed up angiographically for a mean 39.7 months (range 6-72 months), and none of them demonstrated reopening of aneurysm that required additional treatment. Even in tiny ruptured ACoA aneurysms, coil embolization can be a safe and feasible treatment with sophisticated techniques.

Hyperperfusion syndrome (HPS) is a rare but severe complication after carotid artery stenting (CAS). Reliable methods for predicting HPS remain to be developed. We aimed to establish a predictive value of hemorrhagic HPS after CAS. Our retrospective study included 136 consecutive patients who had undergone CAS. We determined the cerebral circulation time (CCT) by measuring the interval between the point of maximal opacification of the terminal portion of the internal carotid artery and the cortical vein. We calculated intraprocedural CCT changes (ΔCCT) by subtracting postprocedural CCT values from preprocedural CCT values. The mean ΔCCT was 0.9 ± 0.9 seconds; 3 patients (2.2%) with prolonged ΔCCT (2.7, 5.4, and 5.8 seconds) developed HPS. The cutoff time of 2.7 seconds predicted hemorrhagic HPS retrospectively with 100% sensitivity and 99% specificity. Our findings suggest that post-CAS HPS can be predicted by using the ΔCCT value obtained by intraprocedural digital subtraction angiography. Patients with a ΔCCT >2.7 seconds require careful intensive hemodynamic and neurologic monitoring after CAS.

Selection of the appropriate diameter of stent is difficult in patients with the size mismatch between the internal carotid artery (ICA) and the common carotid artery (CCA). Although stent overexpansion (SOE) in the ICA after carotid artery stenting (CAS) is suspected of producing restenosis, SOE has not been well established. We discuss its incidence, predictors, and outcomes. We retrospectively reviewed follow-up angiographs of 206 CAS-treated arteries in 201 patients who had undergone CAS. SOE was defined as angiographic evidence of an intimal gap between the non-stented normal and the dilated stented ICA at the distal stent edge. We also collected data on the patients’ clinical status, comorbidities, and radiological and procedural data. Patients with SOE were further followed up closely by duplex ultrasound scans. SOE was detected in nine of 206 CAS-treated ICAs (4.4%). Univariate analysis revealed a significant association between SOE and open-cell stents, the stent diameter (p

We assessed the morphological change of calcified plaque after carotid artery stenting (CAS) in vessels with heavily calcified circumferential lesions and discuss the possible mechanisms of stent expansion in these lesions.We performed 18 CAS procedures in 16 patients with severe carotid artery stenosis accompanied by plaque calcification involving more than 75% of the vessel circumference. All patients underwent multidetector-row computed tomography (MDCT) to evaluate lesion calcification before and within 3 months after intervention. The angiographic outcome immediately after CAS and follow-up angiographs obtained 6 months post-CAS were examined.The preoperative mean arc of the calcifications was 320.1 +/- 24.5 degrees (range 278-360 degrees ). In all lesions, CAS procedures were successfully carried out; excellent dilation with residual stenosisor=30% was achieved in all lesions. Post-CAS MDCT demonstrated multiple fragmentations of the calcifications in 17 of 18 lesions (94.4%), but only cracks in the calcified plaque without fragmentation in one (5.6%). Angiographic study performed approximately 6 months post-CAS detected severe restenosis in one lesion (5.6%) without fragmentation of calcified plaque.Excellent stent expansion may be achieved and maintained in heavily calcified circumferential carotid lesions by disruption and fragmentation of the calcified plaques.

BACKGROUND AND PURPOSE: Our aim was to assess the feasibility of carotid artery stent placement (CAS) for calcified lesions. MATERIALS AND METHODS: Using embolic protection devices (EPDs), we performed 51 CAS procedures in 43 patients with severe carotid artery stenosis accompanied by plaque calcification. Before intervention, all lesions were subjected to multidetector-row CT. The arc of the circumferential plaque calcification was measured on axial source images at the site of maximal luminal stenosis, and the total volume of the plaque calcification was determined. The angiographic outcome immediately after CAS, and intra- and postoperative complications were recorded. RESULTS: The mean arc of calcification was 201.1 ± 72.3° (range, 76–352°), and the mean of the total calcification volume was 154.9 ± 35.4 mm(3) (range, 92–2680 mm(3)). Balloon rupture occurred in 1 procedure (2.0%) at predilation angioplasty; all 51 CAS procedures were successful without clinical adverse effects. Although there was a correlation between the arc of plaque calcification and residual stenosis (r = 0.6, P < .001), excellent dilation with residual stenosis ≤30% was achieved in all lesions. There was no correlation between the total volume of calcification and residual stenosis. None of the patients developed stroke or death within 30 days of the CAS procedure. CONCLUSION: CAS by using EPDs to treat lesions with plaque calcification is feasible even in patients with near-total circumferential plaque calcification.