OBJECTIVES/GOALS: Craniosynostosis is the premature fusion of one or more cranial sutures that produces brain growth constraints and typically requires surgical treatment. We present an age- and sex-specific method to evaluate surgical outcomes using non-invasive 3D photogrammetry that brings objectivity to the current approach for clinical assessment. METHODS/STUDY POPULATION: First, we created standardized head anatomy representations for 2,020 patients (1,081 males, 939 females, age 3.14 ± 3.05 years) without cranial pathology from their computed tomography (CT) images based on our previous methods. We used principal component regression stratified by sex to establish age-specific normative ranges of anatomical variability and we designed a new metric called cranial shape abnormality (CSA) index that calculates the number of standard deviations from normality of a given patient’s head anatomy. We calculated our CSA index in a group of 56 patients (44 male, 12 female) with sagittal craniosynostosis who underwent sagittal craniectomy from their pre- (22 ± 30 days before surgery) and post-surgical (267 ± 63 days after surgery) 3D photograms to evaluate surgical outcomes. RESULTS/ANTICIPATED RESULTS: We observed a reduction in the CSA index from 1.28 ± 0.26 before surgery to 0.87 ± 0.22 after surgery (p < 0.001 with a paired Wilcoxon test). The CSA index decreased in 53 of 56 patients (94.6%), who consistently showed head shape improvements after corrective surgery during clinical evaluation. Linear temporal regression indicates a CSA index decrease of 0.43 ± 0.05 during the first year after surgery. We found no significant correlation between a patient’s age at surgery and the patient’s CSA index after surgery (Pearson’s correlation coefficient 0.17, p = 0.20) or the patient’s change in CSA index before and after surgery (Pearson’s correlation coefficient 0.22, p = 0.11), suggesting that sagittal craniectomy is equally effective for all patients who are between 85 and 331 days old at the time of surgery. DISCUSSION/SIGNIFICANCE: Our new CSA index is a sex- and age-specific metric of head shape anomalies built upon the observed statistical distributions in the normative pediatric population. Our metric can objectively evaluate pre- and post-surgical head shapes and will allow the investigation of the reported variability in surgical outcomes among patients and procedures.