Optimal timing of cranioplasty post-decompressive craniectomy in traumatic brain injury: a systematic review, meta-analysis, and overview of ongoing trials

CP timing alone does not determine safety or efficacy, with risks varying substantially by implant material. Outcomes are critically modified by implant material and perioperative context. Ultra-EC may confer operative and physiological advantages without excess infection or mortality, particularly with synthetic implants, whereas early autologous or allogenic reimplantation carries higher risk of complications and reoperations. These findings argue for moving beyond a simplistic early-versus-late dichotomy and instead shifting towards material- and patient-specific strategies. Harmonised definitions and material-stratified prospective trials incorporating long-term functional outcomes are essential to establish evidence-based guidelines.