Histopathologic Study of the Outer Membrane of Chronic Subdural Hematoma Related to Membrane Permeability

Park, Youn Kwan; Lee, Ki Chan; Lee, Hoon Kap

Abstract

Permeability of membrane of chronic SDH is a unique characteristic. And various types of attenuation of chronic subdural hematoma(SDH) appearing on computerized tomography(CT) scans are related to the changes occurring as the result of recurrent bleeding. The authors have investigated the membrane permeability of SDH according to the histological changes of the outer membrane of chronic SDH. A consecutive series of 19 adult patients with chronic subdural hematoma has been studied in respect to the post-operative subdural drainage after burr-hole craniostomy and closed system drainage. The subdural drain was kept for 5 days. The amount and the pattern of daily drainage were correlated with histological findings of the outer membrane. The outer membrane of chronic SDH was very rich in blood vessels and contains giant capillaries. One electron microscopic finding of giant capillaries was the frequent formation of gap junctions between adjacent endothelial cells. Numerous red or white blood cells was spilling into the interstitial space of the outer membrane. In positive cases to both membrane hemorrhage and surface clot, total amount of drainage was significantly different from the cases without these findings(p=0.0263). In cases without membrane hemorrhage, the presence of migrating inflammatory cell was well correlated with total drainage amount(p=0.028). From these findings it is suggested that endothelial gap junction of macrocapillaies might play an important role in permeability of the outer membrane. But the recent episode of bleeding could act as a barrier and decrease the permeability actually. After resolution of fibrin clot infiltrated inflammatory cells which contribute to fibrinolysis would decrease and then the permeability would increase.