Copyright © 2015 by the Congress of Neurological Surgeons. BACKGROUND: In moyamoya disease (MMD), cerebral revascularization is recommended in patients with recurrent or progressive ischemic events and associated reduced cerebral perfusion reserve. Low-flow bypass with or without indirect revascularization is generally the standard surgical treatment. Intraoperative monitoring of cerebral partial pressure of oxygen (PtiO<inf>2</inf>) with polarographic Clark-type probes in cerebral artery bypass surgery for MMD-induced chronic cerebral ischemia has not yet been described. OBJECTIVE: To describe basal brain tissue oxygenation in MMD patients before revascularization as well as the immediate changes produced by the surgical procedure using intraoperative PtiO<inf>2</inf> monitoring. METHODS: Between October 2011 and January 2013, all patients with a diagnosis of MMD were intraoperatively monitored. Cerebral oxygenation status was analyzed based on the Ptio2/PaO<inf>2</inf> ratio. Reference thresholds of PtiO<inf>2</inf>/PaO<inf>2</inf> had been previously defined as below 0.1 for the lower reference threshold (hypoxia) and above 0.35 for the upper reference threshold (hyperoxia). RESULTS: Before STA-MCA bypass, all patients presented a situation of severe tissue hypoxia confirmed by a PtiO<inf>2</inf>/PaO<inf>2</inf> ratio <0.1. After bypass, all patients showed a rapid and sustained increase in PtiO<inf>2</inf>, which reached normal values (PtiO<inf>2</inf>/PaO<inf>2</inf> ratio between 0.1 and 0.35). One patient showed an initial PtiO<inf>2</inf> improvement followed by a decrease due to bypass occlusion. After repeat anastomosis, the patient's PtiO<inf>2</inf> increased again and stabilized. CONCLUSION: Direct anastomosis quickly improves cerebral oxygenation, immediately reducing the risk of ischemic stroke in both pediatric and adult patients. Intraoperative PtiO<inf>2</inf> monitoring is a very reliable tool to verify the effectiveness of this revascularization procedure.
- Cerebrovascular circulation/physiology