Management of pediatric skull defects after decompressive craniectomy (DC) poses unique problems, particularly in children younger than 24-months. This includes complications including resorption and infection as well as difficulties with plagiocephaly and reconstruction. The goal of this study is to evaluate bone resorption complications after cranioplasty in patients <24 months.A single-center retrospective case-study of all patients under 24-months who underwent cranioplasty after DC between 2011 and 2018 was performed. The following variables were assessed: injury etiology, age at craniotomy, time to cranioplasty, craniectomy size, mode of fixation, drain usage, shunt usage, subdural fluid collection, resorption, need for synthetic graft revision, and plagiocephaly.A total of 10 patients were identified who met inclusion criteria; 3 patients were excluded for insufficient follow-up. Ages ranged <1 day to 19 months with a mean of 10.7 months. Overall rate of cranioplasty resorption was 85.7%, 57.1% of which required revision with synthetic graft. There were univariate trends towards more frequent implant resorption with subdural fluid collection (p=0.1071) and without shunt placement (p=0.1429). These effects persisted through multivariable analysis and even reached statistical significance in the case of subdural collection when controlling for operative and demographic characteristics (p=0.01138, p=0.0694). Additionally, univariate analysis demonstrated a trend towards more frequent neurological complications with greater craniotomy-to-cranioplasty intervals (p = 0.1043) that reached significance on multivariable analysis. (p = 0.00518).In patients under 24-months undergoing cranioplasty subdural collection, a lack of shunt placement, and increased time to cranioplasty were associated with increased rates of resorption.