Acute subdural hematoma is one of the worst post-traumatic mass lesion. It usually occurs at the cerebral convexity. The pure interhemispheric subdural hemorrhage and tentorial subdural hemorrhage (ITSDH) are relatively unusual patterns of subdural hemorrhage. The objective of this study is to evaluate and compare ITSDH with convexity subdural hemorrhage (CSDH).

A retrospective review was done on 21 patients with ITSDH and 26 patients with CSDH among 890 head injured patients from January 2004 to August 2006. Clinical and radiological factors were analyzed statisitically between two groups.

The incidence of ITSDH and CSDH was 2.3% and 2.9%, respectively. All patients of ITSDH had mild neurological sign [glasgow coma score (GCS)>13], but in CSDH there were only 14 patients (55%). Eleven patients of CSDH (43%) underwent operation (p<0.001) and overall mortality was 27%, no patients required operation in ITSDH and all had good recovery (100%). In radiologic findings, skull fractures in CSDH were more frequently observed than in ITSDH, estimated proportions are 31%, 8% in orderly. Also, there was significant relationship between primary impact site and location of ITSDH and CSDH. Coup injury is observed more predominantly in CSDH (69%) but only 6 patients (29%) hold coup injury in ITSDH (p=0.01).

It is suggested that the ITSDH may be occurred by contre coup injury and shows better outcome than CSDH.