Optimal Timing of Cranioplasty After Craniectomy: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES: The optimal timing of cranioplasty (CP) after craniectomy remains uncertain. We aimed to evaluate and compare functional outcomes and complication rates associated with early and late CP after craniectomy. METHODS: We systematically searched PubMed, Scopus, and Web of Science through June 2025. Fifty-five studies (n = 8602 patients) met inclusion criteria, comparing at least 2 distinct CP timing categories. Functional outcomes included Barthel Index (BI), functional independence measure, and modified motor assessment and enhancement scale. Patients were categorized as having undergone ultra-early CP (30-45 days), intermediate CP (45-70 days), early CP (80-100 days), or delayed CP (120-180 days). RESULTS: Early CP significantly improved functional outcomes in BI absolute scores, BI gain scores, absolute functional independence measure scores, and absolute modified motor assessment and enhancement scale scores compared with delayed CP. Ultra-early CP demonstrated the greatest benefit in absolute BI scores and significantly reduced bone flap resorption risk. No significant differences were found in rates of complications. Implant material (autologous vs prosthetic) and traumatic etiology did not significantly affect these outcomes. CONCLUSION: Earlier CP after craniectomy-particularly within 100 days-was associated with improved functional recovery without a significant increase in complications. Although bone flap resorption appeared lower with ultra-early timing, other adverse events such as infection, hydrocephalus, and hematoma did not vary meaningfully across timing windows. These findings suggest that, in carefully selected patients, earlier reconstruction may offer neurological benefits. Because timing was not randomized and may reflect clinical stability and treatment selection, these findings reflect associations and do not establish causality. Further studies are needed.