Takayuki Saguchi

Unruptured Intracranial Aneurysms Incidence of Rupture and Risk Factors

Backgrounds and Purpose— The authors evaluated the incidence of rupture of unruptured intracranial saccular aneurysm during observation. Methods— Between January 2003 and December 2006, a total of 419 patients with 529 unruptured intracranial saccular aneurysms were observed without treatment. The mean follow-up duration was 905.3 days. Aneurysm size was measured by 3-dimensional CT angiography. Clinical and 3-dimensional CT angiography follow-up were obtained every 6 months. Results— Nineteen aneurysms ruptured during observation resulting in a 1.4% rupture rate per year. A history of subarachnoid hemorrhage (hazard ratio, 7.3; 95% CI, 2.5 to 21.2), posterior circulation aneurysm (hazard ratio, 2.9; 95% CI, 1.1 to 8), and large size were significant independent predictors for aneurysm rupture. Conclusions— Size, history of subarachnoid hemorrhage, and posterior circulation aneurysms were significant risk factors for prediction of rupture of unruptured intracranial saccular aneurysms.

Risk Analysis of Unruptured Intracranial Aneurysms: Prospective 10-Year Cohort Study.

Background and Purpose— The natural history of unruptured intracranial aneurysms remains unclear, and management strategy is not well defined. Methods— From January 2003 to December 2012, we enrolled patients with aneurysm in our institution. In total, 2252 patients with 2897 aneurysms were eligible for analysis, and 1960 eligible aneurysms were conservatively managed. Precise 3-dimensional evaluation was conducted using computed tomography angiography, digital subtraction angiography, or magnetic resonance angiography. We then assessed the risk of aneurysm rupture, mortality, and morbidity associated with aneurysm characteristics, demographics, and known health/lifestyle risk factors. Results— The mean follow-up duration was 7388 aneurysm-years. During observation, 56 aneurysms ruptured, resulting in an overall rupture rate per year of 0.76% (95% confidence interval, 0.58–0.98). The mean initial visit to rupture interval was 547 days. Aneurysm size, location, daughter sac, and history of subarachnoid hemorrhage were significant independent predictors for aneurysm rupture. Aneurysms that were ≥5 mm were associated with a significantly increased risk of rupture when compared with 2- to 4-mm aneurysms (unadjusted hazard ratio, 12.24; 95% confidence interval, 7.15–20.93). Of 56 patients who experienced hemorrhage, 29 (52 %) died or were rendered severely disabled. Of the patients who had large or giant aneurysms, none recovered without deficits, and the mortality rate after rupture was 69%. For aneurysms sized <5 mm, the mortality rate was 18%. Conclusions— Larger aneurysms are at greater risk for rupture and poor outcome. Ethnic factors may play a role in the risk of rupture.

Robotic digital subtraction angiography systems within the hybrid operating room.

BACKGROUND:Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. OBJECTIVE:To describe initial clinical experience with a robotic DSA system in the hybrid OR. METHODS:A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. RESULTS:Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. CONCLUSION:This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

Dynact soft-tissue visualization using an angiographic C-arm system: initial clinical experience in the operating room.

INTRODUCTION DynaCT is a clinical application protocol to create computed tomographic (CT)-like images allowing soft-tissue visualization acquired from an angiography system. A cone beam three-dimensional CT reconstruction is produced from the acquisition of two-dimensional projection images by rotating the c-arm with x-ray source and image receptor around the patient. The purpose of this study is to evaluate the clinical efficacy of DynaCT in the operating room. METHODS DynaCT was performed in 100 patients undergoing cerebral or spinal interventional procedures in the new-concept operating room. Specially designed AXIOM Artis BA (conventional image intensifier system; 55 patients; Siemens Medical Solutions, Erlangen, Germany) and AXIOM Artis dBA (flat-panel detector; 45 patients; Siemens Medical Solutions) biplane neuroangiographic systems (Siemens Medical Solutions, Germany) were installed in the operating room. The volumetric data set from the AXIOM Artis systems were reconstructed immediately on the three-dimensional workstation in the operating room. We compared DynaCT images with the use of multidetector computed tomography. RESULTS DynaCT was performed successfully in all patients. High-contrast structures, such as bone, calcified lesions, and metallic materials, were visualized on DynaCT as well as in multidetector computed tomography for each group. Although contrast differentiation of soft tissue such as cerebral cortex, muscle, and hematoma on DynaCT were inferior to multidetector CT scans, the images were sufficiently used as intraoperative CT-like images. However, DynaCT images acquired from flat panel detector-based systems were found to be superior to those images acquired from image intensifier-based systems. Striking ring artifacts were exhibited and resulted in major limitations in the image intensifier group. CONCLUSION DynaCT has the potential to be used as a powerful tool for endovascular and neurosurgical procedures and will open new possibilities for neurosurgical management.

Effective and safe conditions of low-frequency transcranial ultrasonic thrombolysis for acute ischemic stroke: neurologic and histologic evaluation in a rat middle cerebral artery stroke model.

Background and Purpose— Transcranial ultrasound (TUS) enhances thrombolysis and is expected to be useful for the treatment of ischemic stroke. However, neither its effectiveness in improving neurologic outcome nor its safety in living tissue has been fully established. We examined the efficacy and safety of low-frequency TUS under appropriate conditions of ultrasound for thrombolytic treatment in a rat middle cerebral artery stroke model. Methods— Sixty-five male Wistar rats were used. Rats with right middle cerebral artery stroke exhibiting left hemiparesis were blindly selected and randomly assigned to 1 of 3 groups: (1) control, no therapy; (2) tPA, intravenous administration of tissue plasminogen activator 3 hours after middle cerebral artery stroke, or (3) TUS, tPA administration and application of TUS (490 kHz, continuous wave, at an intensity of 0.8 W/cm2). Twenty-four hours after the onset of stroke, neurologic improvement was evaluated and brains were then removed. Thrombolysis at the origin of the right middle cerebral artery was examined. Thrombolysis ratio, cerebral infarct ratio, and rate of histologic evidence of hemorrhage were compared in the 3 groups. Results— Significantly better neurologic improvement (P=0.008), a higher thrombolysis ratio (P=0.041), and a reduction of cerebral infarct volume (P=0.047) were obtained in the TUS group compared with the tPA group, without an increase in hemorrhagic transformation. Conclusions— Our findings suggest that thrombolytic treatment with low-frequency TUS under appropriate conditions could be an effective and safe method of treatment for ischemic stroke.

Infected subdural hematoma

A case is presented in which Escherichia coli seeded a pre-existing chronic subdural hematoma. A 77-year-old woman was admitted to our hospital because of lethargy, left hemiparesis and fever. Drainage through a burr hole was performed with the diagnosis of bilateral chronic subdural hematoma. Operative findings revealed the infected subdural hematoma on the right side and non-infected subdural hematoma on the left side. Cultures of the subdural hematoma grew Escherichia coli. In view of the pyuria, the etiology of the infected subdural hematoma was postulated to be a urinary tract infection. In the majority of 14 reported cases, the causative organisms were Escherichia coli, Salmonella, and the systemic sources of infection included the urinary tract, gastrointestinal disease, or were unknown. The possibility of infected subdural hematoma should be considered when computed tomography findings suggestive of chronic subdural hematoma exist in a patient with signs of infection.

A rabbit model for efficacy evaluation of endovascular coil materials.

BACKGROUND To investigate biomaterials seeking for their possible use for aneurysm treatment, in vivo screening tests using a number of potential materials are required. However, there is no established animal model that is suitable for such purpose. Some models require special preparation of tested materials for transcatheter delivery and others are inappropriate in view of their cost-effectiveness. The purpose of this study is to establish an animal model that overcomes these limitations and help us select potential materials before the preclinical evaluation. METHODS Bilateral CCAs in a rabbit were surgically ligated, and a 2-cm segment of either a bare platinum coil or a polymeric coil (a platinum coil coated with PLGA 10/90) was implanted into each blind-ended arterial segment (n = 26). They were harvested at day 1, 7, 10, 14, or 30, respectively. Angiographic and histologic evaluations as well as quantitative analysis on the development of the organized thrombus were performed. RESULTS One day after the implantation, both platinum and PLGA coils were surrounded by immature thrombus that was induced by blood flow stagnation in the arterial segment. At day 7, minimal thrombus organization was observed around both types of materials. At postimplantation days 10 and 14, fibrocellular responses, the early findings of the thrombus organization process, were observed in both material groups. Such histologic findings were more prominent in the PLGA coil group as compared to the platinum coil group (day 10, P = .051; day 14, P = .011). Well-organized thrombus was observed in both material groups at day 30 without showing statistical difference (P = .12). CONCLUSION Given the cost-effectiveness, the simple material preparation process, and its feasible histologic evaluation methods, this new animal model can be useful in screening other potential biomaterials for the development of new coil devices.