The effectiveness of decompressive craniectomy size in traumatic brain injury; an international, observational, comparative effectiveness study

Introduction: Guidelines recommend large decompressive craniectomies (DC) in traumatic brain injury (TBI), yet the optimal size remains debated. Real-world practice often differs from guideline recommendations and generalizability of prior evidence to a broader TBI population is uncertain. Research question: What is the comparative effectiveness of DC size on 12-month functional outcome in TBI? Material and methods: We selected participants enrolled in the CENTER-TBI diagnosed with TBI who received a hemicraniectomy. Effect of DC size on functional outcome was evaluated with random-effects logistic regression, associating center case-mix adjusted DC sizes to GOSE. Center preference was quantified with the median odds ratio (MOR). Results: Among 4509 patients enrolled in CENTER-TBI, 295 underwent a hemicraniectomy. DC size varied from 37 cm² to 165cm² (IQR 96 cm²-123cm², ellipsoid calculation), with a two-times higher probability of receiving a 27 cm² larger (IQR increase) DC for a similar patient in one center versus another random center (adjusted MOR for DC size 1·7). Only 4 patients received a DC ≥ 12 × 15 cm (cm) or 15 cm in diameter, while 0 patients received a DC ≤ 6 × 8 cm. Larger DC size was not associated with more favorable 12-month GOSE scores (aOR 0.73 for 27 cm2 increase in DC size, 95%CI 0.47-1.1). Discussion and conclusion: DC size varied widely across European centers. Recommended DC sizes were rarely reached, as were very small DC sizes. Larger versus smaller DC was associated with similar outcomes, however heterogeneity in DC indication may have attenuated observable treatment effects. Neurosurgeons may continue to prefer larger over smaller decompressions.