Neurological Surgery最新文献

Currently, no randomized clinical trials have investigated the use of antiplatelet drugs to prevent stroke in patients with Moyamoya disease(MMD). Notably, most of these studies were retrospective observational or prospective with small cohorts. Although the effectiveness of antiplatelet drug administration for ischemic MMD is limited, patients with microembolic signals detected using transcranial Doppler ultrasound may benefit from the prevention of cerebral infarction. There are no data that the administration of antiplatelet drugs increases the risk of hemorrhagic stroke in patients with MMD. However, administration of antiplatelet drugs may increase the patency rate of bypass blood vessels after bypass surgery. Among antiplatelet drugs, cilostazol has a clinically beneficial effect in patients with MMD through its multifaceted effects, such as increasing cerebral blood flow and inhibiting cognitive decline.

Moyamoya disease is a chronic cerebrovascular disorder characterized by progressive stenosis or occlusion of the terminal portion of the internal carotid artery around the circle of Willis, thereby forming fragile collateral vessels(moyamoya vessels). Although ischemic symptoms predominate in pediatric cases, adult cases often involve ischemic and hemorrhagic events. Surgical revascularization effectively improves long-term outcomes; however, perioperative complications, such as ischemic events, hyperperfusion syndrome, and hemorrhagic complications, remain challenging. Perioperative management aims to minimize the risk of ischemia and hemorrhage by stabilizing blood pressure, maintaining fluid and electrolyte balance, and implementing optimal ventilation strategies. Intraoperative management aims to prevent ischemic events by ensuring careful hemodynamic and respiratory monitoring and maintaining adequate cerebral perfusion during bypass procedures. Postoperative care emphasizes the early detection and management of hyperperfusion syndrome using imaging modalities, such as PET and SPECT, together with tailored blood pressure control and pharmacological interventions. Meta-analyses and systematic reviews have underscored the importance of selecting the appropriate surgical technique(direct, indirect, or combined bypass) to minimize complications. Although combined bypass techniques may offer long-term outcomes, particularly in pediatric patients, individualized management strategies are essential to address the complex perioperative risks associated with moyamoya disease. Further research is needed to refine surgical approaches and optimize patient outcomes.

Pregnancy and delivery management in patients with moyamoya disease requires careful attention because of the increased risk of cerebrovascular events. Prepregnancy evaluation, including radiological imaging, neurological assessment, and medication adjustment, is essential. During pregnancy, blood pressure(BP) should be monitored closely to prevent complications, because patients are prone to developing high BP. Delivery should be planned based on the patient's cerebrovascular condition, with vaginal delivery under epidural analgesia management or cesarean section in high-risk cases. Postpartum care includes managing BP and monitoring stroke symptoms. Multidisciplinary collaboration between obstetricians, neurologists, and anesthesiologists is crucial for optimizing outcomes.

We performed direct bypass in adult moyamoya disease and combined direct and indirect bypasses in pediatric cases. Our surgical approach was based on techniques learned from Dr. Hiroyasu Kamiyama, which we refined over time. This paper provides an overview of our method, including its technical modifications and rationale. We performed multiple direct bypasses using the superficial temporal artery(STA) in the anterior and middle cerebral artery territories. Bypass of the anterior cerebral artery is routinely performed in pediatric patients to improve cognitive function. Because secondary bypass using the STA is often unfeasible, we primarily used available resources for the initial surgery. Key procedural refinements include an optimized skin incision to reduce flap ischemia and STA dissection and preparation. Bypass suturing techniques emphasize intima-to-intima anastomosis, which is achieved by optimal stitching to enhance patency and reduce the risk of occlusion. Fish-mouth trimming can achieve a wider orifice while minimizing ischemic time because of the precision of the procedure. Surgical advancements improve the safety and efficacy of moyamoya bypass procedures. Understanding and refining these techniques through continuous training is essential to achieve optimal outcomes.

In indirect bypass surgery for moyamoya disease(MMD) angiogenesis is induced by attaching extracranial tissues to the brain surface, and the external carotid artery system supplements hemodynamic insufficiency in the internal carotid artery system. This procedure is specific to patients with MMD. The history of this procedure includes the development of blood supply sources and ways to efficiently supply blood to various areas of the brain. The mechanism underlying the angiogenesis induced by this procedure remains unclear. Evaluation of the indications for this procedure in adult patients with ischemic MMD and elucidation of its preventive effect on hemorrhagic MMD are warranted.

Moyamoya disease is currently classified as one of the "Specified Intractable Diseases" by the Ministry of Health, Labor, and Welfare. Since the establishment of this classification in 2014, individuals with mild or nonpersistent symptoms or patients who underwent bypass surgery more than 5 years ago are no longer eligible for certification. To address this issue, the Moyamoya Disease Research Group, under the Ministry of Health, Labor, and Welfare, initiated a revision of the severity criteria in 2021; official revision was passed in 2024. The main change in the revision is the "shift from focusing on fixed symptoms to prioritizing future medical needs."

We reviewed the history and development of revascularization surgery for moyamoya disease, particularly STA-MCA bypass. In the early stages, medical treatments, such as vasodilators, were ineffective. In the 1970s, indirect surgical methods were introduced but have shown limited success. Direct bypass techniques have evolved with advancements in microsurgery, and STA-MCA bypass has become the standard treatment. Surgery improves the collateral blood flow and reduces the risk of stroke, especially in patients with ischemia. Despite being generally safe, perioperative complications, such as cerebral infarction and hyperperfusion syndrome, may occur. Adult and pediatric patients show different hemodynamic responses that require tailored postoperative care. Long-term studies have shown high graft patency and reduced risk of stroke, although late cerebrovascular events may occur. Meta-analyses support revascularization, especially in cases of hemorrhage. The optimal timing of surgery remains controversial. The risk factors for postoperative stroke include age < 5 years, diabetes, and a higher Suzuki grade. Continued research is needed to refine individual treatment strategies.

Moyamoya disease is rare and affects children and young adults. A substantial proportion of children with this disease experience cognitive dysfunction in some domains even in the absence of ischemic or hemorrhagic stroke. A characteristic feature is a decline in working memory, which is believed to be associated with reduced blood flow and disrupted microstructure in the frontal and parietal lobes. However, the involvement of the temporo-parietal-occipital lobes has also been reported. While successful bypass surgery can improve cognitive decline in some domains, especially the visual-motor processing ability, some patients still suffer from cognitive decline, which negatively affects school learning. As a primary physician of pediatric patients with moyamoya disease, it is essential to assess not only neurological symptoms but also their educational situation and need for support at each school stage. Furthermore, since children with moyamoya disease will have a long life after initial treatment, it is crucial to transmit our knowledge and current challenges to healthcare providers in the next generation to ensure appropriate support throughout the patients' lives.

The Japan Adult Moyamoya(JAM) Trial revealed the preventive effect of direct bypass on rebleeding in patients with hemorrhagic moyamoya disease. Subsequent studies have elucidated the significance of periventricular anastomosis, a fragile periventricular collateral manifestation, as a source and predictor of hemorrhage. Practitioners should confirm the reduction in periventricular anastomosis after bypass surgery for hemorrhagic moyamoya disease through optimal imaging assessments.

Here, I briefly describe the determination of locus 17q25 on chromosome 17 for a moyamoya disease susceptibility gene, focusing on our study. At the beginning of the study, linkage analysis was challenging. However, our efforts finally achieved statistically significant results at locus 17q25 with a logarithm of odds(LOD) score of 3.11, a maximum LOD score of 4.58, and p-value of 0.00001 with parametric linkage analysis, multipoint analysis, and nonparametric Affected Pedigree Member analysis, respectively. This was due to the good fortune of choosing chromosome 17 as the primary target, given that neurofibromatosis type 1 and moyamoya disease occur simultaneously in some cases. Moreover, our success was largely due to the contributions of our collaborators who precisely determined the disease traits and collected DNA(leukocyte) samples from 103 individuals from 24 families. After our publication in 2000, a research group from Kyoto University searched for the locus 17q25.3 and discovered a mutation in RNF213 gene. Simultaneously, a group from Tohoku University performed a genome-wide association study and determined RNF213 to be a susceptibility gene for moyamoya disease. This occurred 11 years after our first results.