178 The Timing Dilemma: Exploring the Impact of Cranioplasty Timing on Patient Outcomes. A Meta-Analysis of 3,273 patients

INTRODUCTION: Cranioplasty (CP) is crucial after decompressive craniectomy to restore cranial integrity in various intracranial pathologies. However, the optimal timing for CP remains a debate. Existing literature presents a spectrum of studies with varied timings and outcomes, yielding conflicting insights. METHODS: A database search was conducted until April 8th, 2024, to identify studies reporting outcomes of patients that underwent early and late CP, establishing a 90-day cutoff. Primary outcomes were hydrocephalus, infection, reoperation, subdural fluid collection, Activities of Daily Living (ADL) score and Barthel Index (BI). Complication rates of ultra-early CP (<30 days) versus early CP were also evaluated. RESULTS: Among 561 articles screened, 28 met inclusion criteria, analyzing 3,273 patients across 23 cohorts, 4 case-series, and 1 case-control study. Early CP was associated with a higher rate of hydrocephalus (OR=1.82; 95%CI=[1.14,2.90],p=0.01). Furthermore, early CP showed a greater increase in ADL score (MD=17.15; 95%CI=[12.30,22.01], p=0.00001) and a significant increase in BI score from pre-CP to post-CP(MD=25.24; 95%CI=[15.40,35.09], p=0.0001) whereas, late CP demonstrated no significant difference(MD=-10.2; 95%CI=[-22.5,2.09], p=0.10). Late CP had a higher incidence of subdural fluid collection (OR=0.18; 95%CI=[0.04,0.93], p=0.04). Infection rate (OR=0.72; 95%CI=[0.43,1.21], p=0.21) reoperation (OR=1.72; 95%CI=[0.84,3.53], p=0.14) were not statistically significant. Ultra-early CP had comparable complication rates: hygroma (p=0.51), infection (p=0.47) and hydrocephalus (p=0.95) compared to early CP. CONCLUSIONS: This meta-analysis indicates that early CP may benefit subdural fluid collection, BI, and ADL scores, while late CP may improve post-CP hydrocephalus. However, our analysis was primarily limited by the use of observational studies. These findings underscore the critical role of CP timing in optimizing outcomes and minimizing complications, necessitating further clinical trials to inform neurosurgical guidelines.