Two‐Piece Craniotomy Is Associated With Improved Postoperative Outcomes of Combined Revascularization in Patients With Moyamoya Disease

Revascularization for both anterior cerebral artery (ACA) and middle cerebral artery (MCA) territories in patients with moyamoya disease is often performed in a single operation. The influence of craniotomy type on postoperative outcomes has not been investigated. This study aimed to clarify the effects of craniotomy type on acute postoperative outcomes after combined revascularization by comparing 2‐piece, and large 1‐piece craniotomy approaches. This retrospective study included 337 consecutive combined revascularizations of the ACA and MCA territories in patients with moyamoya disease. Surgeries were classified into 2‐piece and large 1‐piece craniotomy groups. For indirect bypass, the following methods were used: (1) large 1‐piece craniotomy and encephalo‐myo‐galeo‐periosteal‐synangiosis for the MCA and ACA territories; (2) 2‐piece craniotomy and encephalo‐myo‐synangiosis for the MCA territory and encephalo‐periosteal‐synangiosis for the ACA territory. Acute postoperative outcomes were compared between the groups. Two‐piece and large 1‐piece craniotomies were performed in 230 and 107 patients, respectively. The incidence of radiological and symptomatic infarction tended to be lower in the 2‐piece craniotomy group than that in the large 1‐piece craniotomy group (3.9% versus 11.2%; P =0.014, and 2.6% versus 6.5%; P =0.12, respectively). Logistic regression adjusted for potential confounders further explained the relationship between craniotomy type and radiological infarction (large 1‐piece/2‐piece craniotomy: odds ratio, 3.1; 95% CI, 1.2–7.6; P =0.015). In combined revascularization of the ACA and MCA territories in moyamoya disease, 2‐piece craniotomy may reduce the risk of postoperative cerebral infarction.