The generally accepted definition of mild head injury includes Glasgow
Coma Scale (GCS) scores of 13 to 15. However, many studies have shown
that there is a heterogeneous pathophysiology among patients with GCS
scores in this range. The current definition of mild head injury is m
isleading because patients classified in this category can have severe
sequelae. Therefore, a prospective study of 1360 head-injured patient
s with GCS scores ranging from 13 to 15 who were admitted to the neuro
surgery service during 1994 and 1995 was undertaken to modify the curr
ent definition of mild head injury. Data regarding patients' age, sex,
GCS score, radiographic findings, neurosurgical intervention, and 6-m
onth outcome were collected and analyzed. The results of this study sh
owed that patients with lower GCS scores tended to have suffered more
serious injury. There was a statistically significant trend across GCS
scores for percentage of patients with positive acute radiographic fi
ndings, percentage receiving neurosurgical interventions, and percenta
ge with poor outcome. The presence of postinjury vomiting did not corr
elate with findings of acute radiographic abnormalities. Based on the
results of this study, the authors divided all head-injured patients w
ith GCS scores ranging from 13 to 15 into mild head injury and high-ri
sk mild head injury groups. Mild head injury is defined as a GCS score
of 15 without acute radiographic abnormalities, whereas high-risk mil
d head injury is defined as GCS scores of 13 or 14, or a GCS score of
15 with acute radiographic abnormalities. This more precise definition
of mild head injury is simple to use and may help avoid the confusion
caused by the current classification.