15 STA–MCA Bypass and EMS/EDMS
Abstract
Moyamoya disease (MMD) primarily affects the middle and anterior cerebral arteries (MCA, ACA). The MCA as well as ACA is involved predominantly in patients with MMD. Symptomatic cases can be treated successfully by using combined (superficial temporal artery) STA–MCA anastomosis and indirect bypass procedures. Direct anastomosis can be successfully achieved in cases of infantile MMD. Combined direct/indirect bypass procedures demonstrates a several advantages over indirect procedures alone. This chapter discusses these advantages as well as technical points of the combined procedure.
15.1 History and Initial Description
Combined direct/indirect bypass for the treatment of moyamoya disease (MMD) has been utilized by the Department of Neurosurgery at Hokkaido University since 1985. 1 The procedure was developed because we had observed complications such as inconsistent and/or suboptimal growth of postoperative revascularization following indirect bypass alone, such as encephalo-duro-arterio-synangiosis (EDAS). 2 Compared with indirect procedures alone, combined superficial temporal artery–middle cerebral artery (STA–MCA) double anastomosis and indirect bypass procedures are more complex, though direct/combined bypass is more often associated with excellent revascularization than indirect bypass. 3
15.2 Indications
Patients with advanced stage of MMD (Suzuki grade III or greater) who demonstrated ischemic symptoms as well as previous history of intracranial hemorrhage are considered candidates for revascularization. In ischemia, symptomatic hemispheres are treated. Asymptomatic hemispheres with hemodynamic compromise may also be treated. Revascularization surgery is performed in bilateral hemisphere of patients with prior history of intracranial hemorrhage.
15.3 Key Principles
Our surgical strategy is characterized by the universal application of both direct and indirect bypass regardless of the patient’s age (Fig. 15‑1). The standard procedure consists of double STA–MCA anastomosis (Fig. 15‑2).
15.4 SWOT Analysis
15.4.1 Strengths
Combined direct/indirect bypass immediately increases regional cerebral blood flow (rCBF) at the site of craniotomy and prevents immediate postoperative ischemic complications. 3 , 4 Postoperative revascularization is more extensive following combined direct/indirect bypass than following indirect procedures alone. 6 Repeated revascularization procedures in the posterior portion of the brain are also less frequently required when compared with indirect procedures alone.
15.4.2 Weaknesses
This procedure can be time consuming and induce hyperperfusion and brain compression due to swelling of the temporal muscle. 5
15.4.3 Opportunities
Symptomatic hemispheres (ischemic attack, stroke, and hemorrhage) are the targets of the combined direct/indirect bypass.
Related posts:
14 Combined STAMCA Bypass and Encephalo-myo-synangiosis
18 STA–MCA Bypass and Encephalo-duro-arterio-synangiosis
17 STA–MCA Anastomosis and EDMAPS
19 Individualized Extracranial-Intracranial Revascularization in the Treatment of Late-Stage Moyamoya Disease
16 Combined Direct (STA–MCA) and Indirect (EDAS) EC–IC Bypass
7 Encephalo-duro-arterio-synangiosis: In Adults
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