RESUMO
Objective To propose the concept of separate interhemispheric subdural effusion, and further study the pathogenesis, diagnosis, treatment and prevention of the disease. Methods 544patients with head injury who were treated by decompressive craniotomy with large bone flap removal (treatment group) or decompressive craniotomy without large bone flap removal (control group) were retrospectively analyzed for understanding the incidence of separate interhemispheric subdural effusion and studying the pathogenesis and risk factors of the disease. Results CT examination showed separate interhemispheric subdural effusion occurred in 38 cases, including 14 of unilateral craniotomy and 24 of bilateral craniotomy, in the treatment group, and 8 cases, including 2 of unilateral craniotomy with disposable bone flap and 6 of bilateral craniotomy with disposable flap, in the control group. The difference in the incidence of separate interhemispheric subdural effusion was significant statistically between treatment and control groups (X2=9.758,P=0.002), but not significant between unilateral and bilateral craniotomies in the two groups (X2=0.053,P=0.818). Conclusions Separate interhemispheric subdural effusion is one type of subdural effusion, and related to brain tissue shift after large bone flap craniotomy. It is one of the most common complications after the craniotomy. It can be diagnosed conveniently by the means of imaging. Early diagnosis and treatment will be beneficial for good prognosis, and to reduce the size of the bone window and to avoid brain tissue shift after operation are the best preventive measures.