Posterior glottic diastasis (PGD) is an underappreciated etiology of dysphonia in patients with prior airway reconstruction or prolonged intubation. In endoscopic posterior cricoid reduction (ePCR), cricoid is removed to minimize the posterior glottic gap. Dynamic voice computed tomography (DVCT) permits visualization of the posterior glottis, estimating the amount of cricoid to be removed. Posterior glottic gaps in patients undergoing ePCR were compared to non-dysphonic patients to describe pediatric PGD and establish surgical parameters for ePCR. DVCTs performed in non-dysphonic patients and dysphonic patients undergoing ePCR from 2014 to 2023 were reviewed. EPCR operative reports were queried. Pre- and postoperative Pediatric Voice Handicap Index (pVHI) and Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scores and aerodynamic measures were reviewed. Seventeen pediatric patients who underwent ePCR and 19 non-dysphonic patients were included. Posterior glottic gaps were significantly larger in the dysphonic group (median 2.4 mm [IQR: 2.0, 2.8] vs. 1.3 mm [IQR: 1.1, 1.7], p < 0.001). Mean width of the cricoid removed was 1.6 mm (SD 0.4 mm). Mean (SD) pre- and postoperative pVHI scores were 55.5 (19.9) and 34.6 (16.0; p < 0.001). Mean (SD) pre- and postoperative CAPE-V scores were 52.7 (15.4) and 36.5 (20.4; p < 0.001), respectively. Children in this cohort tolerated an average 1.3 mm posterior glottic gap without dysphonia. Dysphonic patients with PGD had a median 2.4 mm gap and underwent cricoid reduction by 1.6 mm. All ePCR patients demonstrated improvement in dysphonia. Results seek to optimize the management of pediatric PGD and present a safe and effective amount of cricoid to remove during ePCR. 4 Laryngoscope, 2024.