Moyamoya disease: a summary

Abstract

<jats:p>Moyamoya, meaning a “hazy puff of smoke” in Japanese, is a chronic, occlusive cerebrovascular disease involving bilateral stenosis or occlusion of the terminal portion of the internal carotid arteries (ICAs) and/or the proximal portions of the anterior cerebral arteries and middle cerebral arteries (MCAs). The Ministry of Health and Welfare of Japan has defined 4 types of moyamoya disease (MMD): ischemic, hemorrhagic, epileptic, and “other.” The ischemic type has been shown to predominate in childhood, while the hemorrhagic type is more often observed in the adult population. The highest prevalence of MMD is found in Japan, with a higher female to male ratio. Studies have shown a possible genetic association of MMD linked to chromosome 17 in Japanese cases as well as in cases found in other demographics. During autopsy, intracerebral hematoma is found and most commonly serves as the major cause of death in patients with MMD. Moyamoya vessels at the base of the brain are composed of medium-sized or small muscular arteries emanating from the circle of Willis, mainly the intracranial portions of ICAs, anterior choroidal arteries, and posterior cerebral arteries, forming complex channels that connect with distal positions of the MCAs. Off of these channels are small tortuous and dilated vessels that penetrate into the base of the brain at the site of the thalamoperforate and lenticulostriate arteries. On angiography, there is the characteristic stenosis or occlusion bilaterally at the terminal portion of the ICAs as well as the moyamoya vessels at the base of the brain. Six angiographic stages have been described, from Stage 1, which reveals a narrowing of the carotid forks, to Stage 6, in which the moyamoya vessels disappear and collateral circulation is produced solely from the external carotid arteries. Cases with milder symptoms are usually treated conservatively; however, more severe symptomatic cases are treated using revascularization procedures. Surgical treatments are divided into 3 types: direct, indirect, and combined/other methods. Direct bypass includes superficial temporal artery-MCA bypass or use of other graft types. Indirect procedures bring in circulation to the intracranial regions by introducing newly developed vasculature from newly approximated tissues. These procedures may not be enough to prevent further ischemia; therefore, a combination of direct and indirect procedures is more suitable. This article will give a review of the epidemiology, natural history, pathology, pathophysiology, and diagnostic criteria, including imaging, and briefly describe the surgical treatment of MMD.</jats:p>

Low-flow and high-flow neurosurgical bypass and anastomosis training models using human and bovine placental vessels: a histological analysis and validation study

“…This knot was made between the needle end of the suture and the preceding external suture loop. The other technique entailed both poles of the arteriotomies connected by separate microsutures with the [6][7][8][9][10][11][12] for human placental artery vs 12 [8][9][10][11][12][13][14][15] for M 4 .) The 1.8-mm diameter human placental artery most closely approximates the STA, although the thickness and amount of reticular fibers is statistically significantly different (p < 0.01 and p < 0.01, respectively); however, in practice such differences are not apparent during surgical procedures.…”

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N eurosurgical vascular cases often require complex microvascular bypass techniques, such as those used in operative corrections for moyamoya disease, 7,26,32 cerebral aneurysms, 9,13,14,19 and intracranial tumors. 30,31 Therefore, simple and accessible models for microvascular anastomosis training are increasingly essential for providing a means for refining and preserving skills.

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Protein S Deficiency and an Adult Case with Moyamoya Syndrome that Presented with Primary Intraventricular Haemorrhage

“…Clinically, the presentation of patients with MMD may include transient ischaemic attacks, ischaemic strokes, haemorrhagic strokes, and seizures. Intracranial haemorrhage is common in adults between the ages of 30-50 with a higher occurrence in females and the most frequent site being intraventricular (1)(2)(3)(4). In this case report, age, gender, clinical findings and the location of haemorrhage are consistent with previous reports.…”

“…PIVH, haemorrhage in the ventricular system without a recognisable parenchymal component, is a rare neurological disorder (9). Moyamoya is defined as a non-atherosclerotic, non-inflammatory, and nonamyloid vasculopathy of unknown aetiology (1,2). In adults, the diagnosis of Moyamoya is defined by 3 angiographic criteria, based on the Japanese Ministry of Health and Welfare guidelines.…”

Two Unusual Cases of the Posterior Cranial Fossa Blood Supply

“…There is also an extracranial collateral circulation through the external carotid arteries, especially through the anastomosis with the ethmoidal branches of the ophthalmic artery, as well as dural and meningeal arteries [3]. The extent of the non-fetal collaterals increases with age and with some pathologic diseases, such as Moya Moya [4]. The primary connections between the internal carotid and vertebrobasilar circulations are the posterior communicating arteries [5].…”