Early Excision and Late Excision of Heterotopic Ossification after Traumatic Brain Injury Are Equivalent: A Systematic Review of the Literature

Heterotopic ossification (HO) is a common complication in patients with coma after brain injury. As the optimal timing of surgical resection is still controversial and unclear, a review of the literature was performed in order to determine the impact of early operation on recurrence rate and joint mobility. We identified all types of studies dealing with surgical excision of HO in patients after head injury in major medical and publishers' databases. Publication bias and statistical heterogeneity were assessed by funnel-plot asymmetry and Galbraith regression. We abstracted demographic and outcome information from manuscripts that tabulated individual patient data (IPD) to build univariate logistic and linear regression models. Means and proportions for random-effects meta-regression analysis were also obtained. Of 318 studies originally identified, 16 observational studies enrolling 255 patients (212 men, 329 affected joints, mean age of 30.6 [±SEM of 1.4] years) were included in the analysis. The reported overall recurrence rate in eleven studies was 38/192 (19.8%). Both IPD and meta-regression analysis failed to show a marked impact of the interval to resection on the probability of recurrence (odds ratio 1.00, 95% CI 0.98–1.03). The predicted probability of recurrence after 13, 21, and 30 months of waiting was 9%, 14%, and 19%, respectively. The length of coma period and patient's neurologic deficit were statistically significant negative predictors for both recurrence rate and functional outcome. Although no conclusive inferences can be drawn from the identified studies, the available data do not support the concept that early excision triggers later recurrence.