Intracranial artery dissection (IAD) is a relatively rare cause of stroke, but it has been recognized increasingly with recent advances of the neuroimaging technique. Since rebleeding occurs frequently in the acute stage in the ruptured IAD, urgent surgical treatment should be performed to prevent rebleeding. On the other hand, surgical treatment for unruptured IAD is controversial because it has little risk for bleeding. However, surgical treatment for unruptured IAD may be considered if the formation or enlargement of the aneurysmal dilatation has been confirmed. Since there are several proposed surgical strategies for IAD, it is important to select an appropriate strategy on a case-by-case basis. If the risk of infarction due to vessel occlusion is high, combined bypass surgery should be considered.
Cerebral arterial dissection is defined as a hematoma in the wall of a cervical or an intracranial artery. Cerebral arterial dissection causes arterial stenosis, occlusion, and aneurysm, resulting in acute infarction and hemorrhage. Image analysis by such methods as conventional angiography, computed tomography, magnetic resonance imaging, and so on plays an important role in diagnosing cerebral arterial dissection. In this study, we explore the methods and findings involved in the diagnosis of cerebral arterial dissection.
Developmental venous anomalies (DVAs), previously called venous angiomas, are the most frequently encountered cerebral vascular malformations. However, DVA is considered to be rather an extreme developmental anatomical variation of medullary veins than true malformation. DVAs are composed of dilated medullary veins converging centripetally into a large collecting venous system that drains into the superficial or deep venous system. Their etiology and mechanism are generally accepted that DVAs result from the focal arrest of the normal parenchymal vein development or occlusion of the medullary veins as a compensatory venous system. DVAs per se are benign and asymptomatic except for under certain unusual conditions. The pathomechanisms of symptomatic DVAs are divided into mechanical, flow-related causes, and idiopathic. However, in cases of DVAs associated with hemorrhage, cavernous malformations (CMs) are most often the cause rather than DVAs themselves. The coexistence of CM and DVA is common. There are some possibilities that DVA affects the formation and clinical course of CM because CM related to DVA is generally located within the drainage territory of DVA and is more aggressive than isolated CM in the literature. Brain parenchymal abnormalities surrounding DVA and cerebral varix have also been reported. These phenomena are considered to be the result of venous hypertension associated with DVAs. With the advance of diagnostic imagings, perfusion study supports this hypothesis demonstrating that some DVAs have venous congestion pattern. Although DVAs should be considered benign and clinically silent, they can have potential venous hypertension and can be vulnerable to hemodynamic changes.
The topographical distribution of dural arteriovenous fistulas (DAVFs) was analyzed based on the embryological anatomy of the dural membrane. Sixty-six consecutive cases of intracranial and spinal DAVFs were analyzed based on the angiography, and each shunt point was identified according to the embryological bony structures. The area of dural membranes was categorized into three different groups: a ventral group located on the endochondral bone (VE group), a dorsal group located on the membranous bone (DM group) and a falco-tentorial group (FT group) located in the falx cerebri, tentorium cerebelli, falx cerebelli, and diaphragm sellae. The FT group was designated when the dural membrane was formed only with the dura propria (meningeal layer of the dura mater) and not from the endosteal dura. Cavernous sinus, sigmoid sinus, and anterior condylar confluence was categorized to VE group, which had a female predominance, more benign clinical presentations, and a lower rate of cortical and spinal venous reflux. Transverse sinus, confluence, and superior sagittal sinus belonged to the DM group. Olfactory groove, falx, tent of the cerebellum, and nerve sleeve of spinal cord were categorized to the FT group, which presented later in life and which had a male predominance, more aggressive clinical presentations, and significant cortical and spinal venous reflux. The DAVFs was associated with the layers of the dural membrane characterized by the two different embryological bony structures. The FT group was formed only with the dura propria as an independent risk factor for aggressive clinical course and hemorrhage of DAVFs.
Most of cerebral aneurysms (CAs) are incidentally discovered without any neurological symptoms and the risk of rupture of CAs is relatively higher in Japanese population. The goal of treatments for patients with CAs is complete exclusion of the aneurysmal rupture risk for their lives. Since two currently available major treatments, microsurgical clipping and endovascular coiling, have inherent incompleteness to achieve cure of CAs with some considerable treatment risks, and there is no effective surgical or medical intervention to inhibit the formation of CAs in patients with ruptured and unruptured CAs, new treatment strategies with lower risk and higher efficacy should be developed to prevent the formation, growth, and rupture of CAs. Preemptive medicine for CAs should be designed to prevent or delay the onset of symptoms from CAs found in an asymptomatic state or inhibit the de novo formation of CAs, but we have no definite methods to distinguish rupture-prone aneurysms from rupture-resistant ones. Recent advancements in the research of CAs have provided us with some clues, and one of the new treatment strategies for CAs will be developed based on the findings that several inflammatory pathways may be involved in the formation, growth, and rupture of CAs. Preemptive medicine for CAs will be established with specific biomarkers and imaging modalities which can sensor the development of CAs.
Neurosurgery has tremendous possibilities for development of innovative medical devices. However, most of the neurosurgical devices used in Japan are imported products. Promotion and development of domestic medical devices is highly encouraged and it is one of the pillars of Prime Minister Shinzo Abe’s growth strategy of Japanese economy. Innovative “Made in Japan” medical devices can be developed by interdisciplinary collaboration between industries and academic institutions. Proper orientation of medical and engineering education, social and administrative awareness of the need of facilitating the medical devices creative process with corresponding regulatory changes, and appropriate medical and technological infrastructure establishment are needed for stimulating medical device innovation.
Perioperative management is critical for positive neurosurgical outcomes. In order to maintain safe and authentic perioperative management, a perioperative management center (PERIO) was introduced to patients of our Neurosurgery Department beginning in June 2014. PERIO involves a multidisciplinary team consisting of anesthesiologists, dentists/dental hygienists/technicians, nurses, physical therapists, pharmacists, and nutritionists. After neurosurgeons decide on the course of surgery, a preoperative evaluation consisting of blood sampling, electrocardiogram, chest X-ray, and lung function test was performed. The patients then visited the PERIO clinic 7–14 days before surgery. One or two days before surgery, the patients without particular issues enter the hospital and receive a mouth cleaning one day before surgery. After surgery, postoperative support involving eating/swallowing evaluation, rehabilitation, and pain control is provided. The differences in duration from admission to surgery, cancellation of surgery, and postoperative complications between PERIO and non-PERIO groups were examined. Eighty-five patients were enrolled in the PERIO group and 131 patients in the non-PERIO group. The duration from admission to surgery was significantly decreased in the PERIO group (3.6 ± 0.3 days), compared to that in the non-PERIO group (4.7 ± 0.2 days). There was one cancelled surgery in the PERIO group and six in the non-PERIO group. Postoperative complications and the overall hospital stay did not differ between the two groups. The PERIO system decreased the duration from admission to surgery, and it is useful in providing high-quality medical service, although the system should be improved so as not to increase the burden on medical staff.
We report two cases of juvenile cerebral infarction caused by bow hunter’s syndrome (BHS) during sport. Case 1 was a 17-year-old male who developed a partial visual field defect after playing basketball. BHS was diagnosed because cervical ultrasonography demonstrated occlusion of the vertebral artery when the neck was rotated. After C1–2 posterior fixation was performed, his symptoms resolved. Case 2 was an 18-year-old male with recurrent visual disturbance after playing handball. Cerebral infarction occurred repeatedly despite antiplatelet therapy. After 3 years, vertebral artery dissection was diagnosed and stenting was performed, but his symptoms did not resolve. BHS was diagnosed when he was examined at our department. C1–2 posterior fixation was performed and his symptoms resolved. In these two cases, BHS was caused by sporting activity. For accurate diagnosis and treatment of BHS, neuroimaging with cervical rotation is mandatory.