The 11 September 2001 terrorist attacks on the World Trade Center (WTC) resulted in thousands of deaths and injuries. Research on previous bombings and explosions has shown that head injuries, including traumatic brain injuries (TBIs), are among the most common injuries.

The objective of this study was to identify diagnosed and undiagnosed (undetected) TBIs among persons hospitalized in New York City following the 11 September 2001 WTC attacks.

The medical records of persons admitted to 36 hospitals in New York City with injuries or illnesses related to the WTC attacks were abstracted for signs and symptoms of TBIs. Diagnosed TBIs were identified using the International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes. Undiagnosed TBIs were identified by an adjudication team of TBI experts that reviewed the abstracted medical record information. Persons with an undiagnosed TBI were contacted and informed of the diagnosis of potential undetected injury.

A total of 282 records were abstracted. Fourteen cases of diagnosed TBIs and 21 cases of undiagnosed TBIs were identified for a total of 35 TBI cases (12% of all of the abstracted records). The leading cause of TBI was being hit by falling debris (22 cases). One-third of the TBIs (13 cases) occurred among rescue workers.More than three years after the event, four out of six persons (66.67%) with an undiagnosed TBI who were contacted reported they currently were experiencing symptoms consistent with a TBI.

Not all of the TBIs among hospitalized survivors of the WTC attacks were diagnosed at the time of acute injury care. Some persons with undiagnosed TBIs reported problems that may have resulted from these TBIs three years after the event. For hospitalized survivors of mass-casualty incidents, additional in-hospital, clinical surveys could help improve pre-discharge TBI diagnosis and provide the opportunity to link patients to appropriate outpatient services. The use and adequacy of head protection for rescue workers deserves re-evaluation.