One of the complications which follow injury of the head is the accumulation of cerebrospinal fluid between the dura and the arachnoid. This is called meningitis serosa traumatica, traumatic arachnoiditis, post-traumatic subdural cyst, circumscribed hydrocephalus or subdural hydroma. Since the lesion frequently is not recognized, and the symptoms are attributed to cerebral injury, we believe a review based on our series of 19 cases is justified.
As early as 1894, Charles H. Mayo1 reported a typical case of subdural hydroma but classified the lesion as a cerebral cyst. A boy of 12 who had sustained an injury of the head was brought to him because of severe headache, aphasia and right hemiplegia. Trephining on the left side, Mayo found in the subdural space a circumscribed collection of fluid resembling cerebrospinal fluid. The cyst was evacuated and drained; although the brain did not reexpand immediately after the operation, the late