Angiographic and Clinical Results of Indirect Bypass Surgery for Moyamoya Disease

Lee, Jung pyo; Cho, Sung Jin; Park, Hyung Ki; Park, Sukh Que; Chang, Jae Chil; Choi, Soon Kwan

Abstract

OBJECTIVE
This study aimed to verify the validity and effectiveness of indirect bypass surgery as a treatment for Moyamoya disease. The development of post-surgical collateral circulation was investigated, and the clinical effectiveness of the surgery was confirmed.
METHODS
Of 45 patients (66 hemispheres) with Moyamoya disease, 28 (42 hemispheres) were followed by cerebral angiography for at least 6 months after surgery, between May 2002 and May 2009. There were eight men (13 hemispheres) and 20 women (29 hemispheres) with an average age of 24 +/- 17.1 years (range, 2-62 years) at the time of diagnosis. The average follow-up period was 23 +/- 18.6 months (range, 6-67 months). Indirect revascularization surgery was performed as encephaloduroarteriomyosynangiosis (EDAMS) in 39 cases, encephaloduroarteriosynangiosis (EDAS) in three cases, and bifrontal encephalogaleoperiosteal synangiosis (BEGPS) in 21 cases. The development of collateral circulation was assessed by cerebral angiography at least 6 months after surgery to evaluate the results of the indirect revascularization surgery. For the classification, good indicated collateral circulation of more than two-thirds of the middle cerebral artery distribution; fair between one- and two-thirds; and poor very weak or no collateral circulation. The development of collateral circulation was compared according to age, gender, clinical feature, surgical method, and Suzuki stage.
RESULTS
Cerebral infarction was the most frequent clinical feature at the time of incidence (27 cases; 64.4%), and Suzuki stage 3 was most common (15 cases; 35.7%). Based on cerebral angiography, 85.7% of patients showed good or fair development of collateral circulation, which was better among pediatric patients (< or =15-years-of-age) than adult patients (>15-years-of-age; p = 0.0344). Compared with EDAS, EDAMS tended to show better surgical results, but the difference was not statistically significant. Gender, clinical feature, or Suzuki stage did not influence the results. Among 21 patients in whom BEGPS was performed, 15 (71.4%) showed good or fair development of collateral circulation.
CONCLUSION
Among the Moyamoya disease patients who received indirect bypass surgery, about 85% showed good or fair results, with collateral circulation involving more than one-third of the middle cerebral artery area. In addition to its effect in pediatric patients younger than 15-years-of-age, indirect bypass surgery also resulted in the development of collateral circulation in adults. EDAMS showed better effectiveness than EDAS as a surgical method. It is speculated that multiple, open arachnoid membranes stimulate the development of collateral circulation. One shortcoming of indirect bypass surgery for Moyamoya disease is that several months are required for the development of collateral circulation. One advantage is that it enables sufficient collateral circulation to develop in those who cannot endure direct bypass surgery. More effective results are expected with BEGPS.