Speakers

Pediatric moyamoya disease: postoperative complications and countermeasures
1109 15:05-15:20
Interim Meeting of AASPN/303A
Moyamoya disease (MMD) is the most common surgically treated pediatric cerebrovascular disease in East Asia, characterized by occlusion of bilateral internal carotid arteries. Surgery is the only effective treatment to prevent ischemic and hemorrhagic infarction and indirect bypass is effective for pediatric MMD. We have been performing indirect bypass for MMD since 1987 in our institute. However, we have experienced complications such as postoperative infarction and hemorrhage which seemed inevitable. Therefore, we have pondered how to reduce these postoperative complications. Analysis of 1241 indirect bypass surgeries in 659 pediatric MMD patients on clinical outcome and risk factors on postoperative infarction revealed 63 symptomatic infarctions in 61 patients with overall incidence of 5.1%. Incidence of infarction was higher in patients under 6 years of age and was higher when two craniotomies (EDAS + other site EDAS or EGS) were performed at once. Instead, single craniotomy or single craniotomy with multiple burr hole EGPS at other site was relatively safer, and correction of postoperative hemoglobin level higher than 13 g/dL was significantly correlated with decreased infarction risk. One of the suspected cause of postoperative infarction was arachnoid dissection which was routinely performed at our institute. We have hypothesized that arachnoid dissection promotes vasospasm of cortical vessels, and cause CSF overdrainage. Thus, we have started preserving arachnoid membrane since 2016 and analyzed clinical data of 103 patients each for arachnoid dissection and preservation groups. Two groups showed no significant difference in clinical and revascularization outcomes but arachnoid preservation group showed significantly lower incidence of unfavorable postoperative imaging. Incidence of reoperations due to postoperative complications was 4.8%, but have reduced to 0.9% after starting arachnoid preservation. Also, the incidence of postoperative epidural hemorrhage (EDH) seemed to be higher in MMD patients compared to non-MMD patients from our clinical experience. This is possibly due to collateral vessels of scalp and skull developed in MMD patients. Analysis of 250 craniotomies in 148 MMD patients revealed 32 (12.8%) EDH and in 12 (4.8%) cases, surgical treatment was needed. Compared with 743 non-MMD craniotomies, MMD was related with significantly higher rate of postoperative EDH. Insertion of subcutaneous drain and correction of prothrombin time international normalized ratio lower than 1.20 showed protective effects against EDH. MMD surgery is a preventive treatment to protect against future infarction, and perioperative complications are closely related to an unfavorable long-term outcome. Postoperative complications occur regardless of thorough management. Our efforts such as correction of hemoglobin and prothrombin time levels, avoidance of performing two craniotomies at once, preservation of arachnoid membrane, and insertion of subcutaneous drain have minimized complications of indirect bypass in pediatric MMD patients. Further investigations to reduce postoperative complications of MMD patients should be made.