en Neurosurgery Neurosurgery Original Research Original Research To determine the factors affecting the outcome of patients with traumatic acute subdural hematoma, we reviewed the records of7 4 consecutive comatose patients with a Glascow coma scale Score (GCS) of less than 8 who had been admitted to Imam Hosein Medical Center from 1990 to 1996 and had undergone a uniform treatment protocol. The overall mortality rate was 73% and 23% had functional recovery, but 4% were severely disabled or vegetative. The following variables had a statistically significant correlation with poor outcome: age over 65 years (p<0.05), preoperative GCS of 3 or 4 (p<0.05), bilateral absent pupillary light reflexes (p<0.05), and immediate and sustained coma from the moment of injury to operation without any lucid interval (p<0.00l). The time interval between injury and operation, sex, mechanism of injury, and associated craniocerebral injuries were not significantly correlated with outcome. In patients with immediate post-traumatic unconsciousness, the extent of primary brain injury is the crucial factor to predict the outcome. However, in patients with a lucid interval, the mass effect of hematoma seems to be more important, therefore prompt surgical decompression in addition to management of secondary brain insults improves the outcome remarkably. Acute subdural hematoma, GCS, lucid interval, outcome 313 318 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-431&slc_lang=en&sid=1 SHIRZAD AZHARI 20031947532846004710 20031947532846004710 Yes From the Department of Neurosurgery, Imam Hosein Medical Center, Shaheed Beheshti University of Medical Sciences, Tehran, Islamic Republic of Iran HOSEIN SAFDARI 20031947532846004711 20031947532846004711 No MASSOUD SHABEHPOOR 20031947532846004712 20031947532846004712 No HOSEIN NAYEBAGHAIE 20031947532846004713 20031947532846004713 No ZOHREH AMIRI 20031947532846004714 20031947532846004714 No