[Six cases of organized chronic subdural hematoma].

Surgical procedures for chronic subdural hematoma (CSDH) are performed using various methods on the basis of burr hole irrigation and drainage, but treatment for organized CSDH is rarely required. Primary operation for CSDH was performed in our hospital for 535 patients (391 men, 144 woman; age, 8 months to 104 years) between December 1991 and March 2007. Of these, 6 patients diagnosed with organized CSDH were reviewed. Five patients had a history of burr hole surgery. Computed tomography showed membranous structure and heterogenous distribution of air after burr hole surgery had perforated the subdural space. As for treatment, craniotomy was performed in all cases (small craniotomy, n=4; enlarged craniotomy, n=2), and additional treatment was required in 2 patients. Diagnosis of organized CSDH is not easy before a primary operation, but removal of both organized CSDH and the outer membrane by craniotomy in proportion to hematoma expansion is important once the presence of organized CSDH has been determined.