Factors associated with the development and outcome of hydrocephalus after decompressive craniectomy for traumatic brain injury.

Posttraumatic hydrocephalus (PTH) is common in patients undergoing decompressive craniectomy (DC) for traumatic brain injury (TBI), but the incidence, mechanisms, and risk factors have not been fully elucidated. This study aimed to determine the incidence of and the factors associated with PTH. We retrospectively reviewed patients who underwent DC for TBI at our institute between January 2014 and December 2018. We identified and compared the demographic, clinical, and radiological data, and 12-month functional outcome (as assessed by the Glasgow Outcome Scale [GOS]) between patients who developed PTH and those who did not. Logistic regression analyses were performed to identify risk factors for PTH. Additionally, the influence of PTH on unfavorable functional outcome was analyzed. PTH developed in 18 (18.95%) of the 95 patients who survived at 1 month after DC. A multivariate analysis indicated that postoperative intraventricular hemorrhage (odds ratio [OR] 4.493, P = 0.020), postoperative subdural hygroma (OR 4.074, P = 0.021), and postoperative hypothermia treatment (OR 9.705, P = 0.010) were significantly associated with PTH. The 12-month functional outcome significantly differed between the patients who developed PTH and those who did not (P = 0.049). Patients who developed PTH had significantly poorer 12-month functional outcomes than those who did not (P = 0.049). Another multivariate analysis indicated that subdural hemorrhage (OR 6.814, P = 0.031) and the presence of at least one dilated pupil before DC (OR 8.202, P = 0.000) were significantly associated with unfavorable functional outcomes (GOS grades 1-3). Although the influence of PTH (OR 5.122, P = 0.056) was not statistically significant in the multivariate analysis, it had a great impact on unfavorable functional outcomes. PTH considerably affects functional outcomes at 12 months after DC for TBI. Furthermore, postoperative imaging findings such as intraventricular hemorrhage and subdural hygroma can predict the development of PTH; therefore, careful observation is required during the follow-up period.