OBJECTIVE: To describe the long-term functional outcome of traumatic brain injury (TBI) patients treated by decompressive craniectomy (DC). METHODS: Data was collected on decompressive craniectomy performed on TBI patients admitted between May 1, 2018, and May 1, 2021, using a multi-center, cross-sectional study design. The long-term outcomes of survivors were assessed using a structured extended Glasgow Outcome Scale (GOSE) questionnaire. Descriptive statistics, including frequency, mean, median, and range, were analyzed. Predictors of functional outcomes were determined using multivariate regression analyses. RESULTS: In this study, 74 patients were examined. The mean age at the time of DC was 33.9 years, with a male:female ratio of 11:1. Primary DC was performed in 93.2% of cases. The in-hospital and overall mortality rates were 24.3% and 36.5% respectively. Overall, a favorable functional outcome (GOSE ≥4) was witnessed in 43 patients (58.1%). Among survivors, 91.5% had favorable outcomes. Age ≥40 years, Glasgow Coma Scale (GCS) score ≤5, chest infections, and noninfectious complications were independent predictors of an unfavorable functional outcome (GOSE<
4). Patients with GCS ≤5 fared the worst, with an unfavorable functional outcome rate of 85.7%. CONCLUSIONS: Our results showed that a significant number of our patients had favorable functional outcome after DC for TBI comparable to results from high-income countries. We found that age, admission GCS, postoperative chest infection, and noninfectious complications were all independent factors predicting unfavorable functional outcome. In particular, patients with GCS ≤5 had a higher rate of mortality and unfavorable outcome.