Neurological Surgery最新文献

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.

The Research Committee on Moyamoya Disease(Spontaneous Occlusion of the Circle of Willis) of the Ministry of Health, Labor and Welfare of Japan was established in 1977. The committee has developed diagnostic criteria and therapeutic guidelines for moyamoya disease. Several multicenter clinical studies, conducted by the research committee, have clarified pathophysiological features of the disease and provided strong evidence for effective treatments.

Moyamoya disease(MMD) is a progressive cerebrovascular disorder characterized by the stenosis or occlusion of the terminal portion of the internal carotid artery and its major branches. Surgical revascularization is important in the management of patients with MMD. This report compared the long-term outcomes of direct, indirect, and combined bypass techniques focusing on stroke recurrence rates and functional prognosis. Recent meta-analyses and clinical reports suggest that combined bypass provide the best long-term outcomes, reducing the risk of stroke recurrence and improving hemodynamic stability. These findings are crucial for neurosurgeons in selecting the optimal surgical approach for adult patients with MMD.

Moyamoya disease(MMD) is a progressive cerebrovascular disorder characterized by stenosis or occlusion of the terminal portion of the internal carotid arteries and development of abnormal collateral vessels. Recent studies have suggested a clinical association between MMD and autoimmune thyroid disorders or antithyroid antibodies. In patients with concurrent Graves'disease, thyrotoxicosis may precipitate ischemic cerebrovascular events, and normalization of thyroid function is crucial before revascularization surgery. Notably, elevated levels of antithyroid autoantibodies, such as antithyroid peroxidase and anti-thyroglobulin, are frequently observed in patients with MMD, despite the absence of clinically overt thyroid dysfunction. Genetic susceptibility, including RNF213 variants and immunological factors, might contribute to the pathophysiology of MMD and autoimmune thyroid disorders. The presence of thyroid autoantibodies may be associated with the pathological extension and cerebrovascular events in MMD. However, the underlying mechanisms linking thyroid autoimmunity and moyamoya angiopathy remain unclear. Further investigation is warranted to elucidate these associations and establish appropriate diagnostic and therapeutic approaches.