Exploring the Effects of Traumatic Brain Injuries on Cranial Nerve Injury

Traumatic brain injuries (TBI) are a significant and growing health issue, leading to over 200 000 hospitalizations annually in the United States. Cranial nerve (CN) injuries accompanying TBI can severely impact patients' quality of life. This review aims to address the gap in research regarding the severity, mechanisms of injury, and associated intracranial injuries, emphasizing the importance of early detection and intervention.

A comprehensive literature search was conducted across databases such as PubMed and Ovid using key terms, including "cranial nerve injury," "cranial nerve palsy," "traumatic brain injury," and "Glasgow Coma Scale." Inclusion criteria encompassed studies reporting CN injuries with TBI, categorized by Glasgow Coma Scale (GCS) scores, and the mechanisms of injury. A total of 14 studies were reviewed, integrating data from adult and pediatric populations.

The incidence of CN injuries in TBI patients varies in the literature, with studies reporting rates between 5%-23%. Data revealed significant occurrences of CN injuries in mild (GCS scores 13-15), moderate (GCS scores 9-12), and severe (GCS scores < 9) TBI. Common mechanisms of injury included automobile accidents and falls; crush injuries were a notably common mechanism of injury in pediatric patients with TBI. Associated injuries included skull base fractures (38.9%), subdural hematomas (16.6%), epidural hematomas (18.9%), and subarachnoid hemorrhage (25.6%). Early detection and intervention were found to be critical in improving patient outcomes, with delays leading to increased disability and poor prognosis.

The high prevalence of CN injuries in even mild cases of TBIs emphasizes the need for physicians to be equipped to assess, diagnose, and treat CN deficits in all forms of neurological trauma. By acknowledging common mechanisms of injury and associated intracranial injuries, we can elucidate the possibility of CN damage in order to facilitate early recognition and treatment. The identification of CN injury also suggests the importance of investigating other intracranial injuries such as skull base fractures, epidural or subdural hematomas, and hemorrhage.