Routine serial computed tomographic scans in mild traumatic brain injury: when are they cost-effective?

BACKGROUND: Most case series involving routine serial computed tomography (CT) scans of the head in patients with mild traumatic brain injury (TBI) have suggested that they only occasionally provide useful information and imply that the practice is unnecessary and wasteful. No study has looked at the special case in which the initial scan revealed an intracranial abnormality which did not require surgery. METHODS: We performed a structured review of the literature for the probabilities and costs of various outcomes in patients with mild TBI who demonstrate at least one intracranial abnormality on their admission CT scans. We supplemented this data with additional information from a large database of mild TBI patients. We then constructed a decision-analytic model to calculate costs and outcomes, comparing the strategy of routine serial scanning with that of awaiting clinical deterioration before repeating the study (expectant strategy). RESULTS: For the 20-year-old patient, the routine CT strategy is slightly more effective than the expectant strategy and is also only slightly more expensive. With advancing age, the relative cost-effectiveness of routine CT declines. CONCLUSIONS: Awaiting clinical deterioration in patients with mild TBI whose first CT scan reveals intracranial injury is not cost-effective compared with routine follow-up CT scans. Although the difference is not statistically significant, routine follow-up scanning is slightly more cost-effective, especially in younger patients.