The Relationship of Preoperative Computerized Tomographic Scan Image and Amount of Postoperative Closed System Drainage in the Recurrence of Chronic Subdural Hematoma

Lim, Dong Jun; Park, Youn Kwan; Chung, Yong Gu; Kim, Bong Ryong; Chung, Heung Seob; Lee, Ki Chan; Lee, Hoon Kap; Suh, Jung Keun

Abstract

Although chronic subdural hematoma(CSDH) is a well known entity, there is little knowledge concerning whether the results of radiological imaging can be used to predict CSDH recurrence or whether surgical methods can influence this rate. The aims of this study are to evaluate; 1) the relationship between the recurrence rate of CSDHs and their appearance on preoperative computerized tomography(CT) or magnetic resonance(MR) images and 2) relationship between the recurrence rate of CSDHs and the amount of postoperative drainage, and 3) the usefulness of one burr-hole irrigation with close-system drainage. From January 1991 through March 1998, 166 patients who were surgically treated were included. Thirty-six of these patients underwent bilateral operation and thus 202 operative sites of CSDH were analyzed. Preoperative CT was done in 151 patients and MR was done in the others. The cases of CSDH were separated into low-, iso-, layered-, high-, mixed-density groups on the basis of the appearance on CT images, and high-, nonhigh-intensity groups on T1-weighted MR images. All patients had underwent one burr-hole irrigation with closed system drainage and the drain was kept in place for 5 days. The amount of postoperative drainage decreased significantly from the 2nd day after operation compared to the 1st day after operation and decreasing tendency was continued through the rest of the days(p<0.0001) Overall recurrence rate was 3.5% and there was no significant relationship between the recurrence rate and their appearance on preoperative CT or MR. The average amount of postoperative drainage was larger in unrecurred CSDHs(381.0+/-36.9 ml, mean+/-standard error) than recurred cases(188.9+/-40.7ml). One burr-hole irrigation with closed-system drainage was useful regardless of CT findings. The amount of postoperative drainage, which means permeability of hematoma membrane, may be useful in predicting the propensity of CSDHs to recur.