Evaluating 3D Morphometrics for Assessing Micrognathia in Neonates with Severe Pierre Robin Sequence: A Case-Control Study

ObjectiveTo compare 3D mandibular morphometrics of neonates with Pierre Robin sequence (PRS) to age-matched controls, establish normative data, and better understand anatomic differences.DesignRetrospective case-control study.SettingTertiary pediatric medical center.PatientsTwenty-five neonates with non-syndromic PRS (mean age 15 days) with computed tomography (CT) scans of the head and mandibular distraction osteogenesis (MDO) and 25 age-matched controls (mean age 14 days) with CT scans of the head.InterventionsNone.Main Outcome MeasuresStandardized morphometric measurements, including linear distances, angles, and ratios, were generated from digital 3D reconstructions of mandibular anatomy.ResultsAsymmetry in PRS body length was significantly higher than in control mandibles (p = .006). PRS measurements larger than control measurements included intercondylar distance (p = .044), intergonial distance (p = .008), pogonion-interdental distance (p = .015), ramus height (p = .001), and ramus height to body length ratio (p < .001). PRS measurements smaller than control measurements included intercondylar angle (p < .001), body length (p < .001), and effective mandibular length (p < .001).ConclusionsIn a cohort of neonates with PRS severe enough to warrant MDO, findings indicate that micrognathia is constituted by a wide and antero-posteriorly short mandible for its height. Except for body length, PRS and control mandibles are similarly asymmetrical in other dimensions. These findings may contextualize structural abnormalities contributing to glossoptosis and airway obstruction in PRS, with implications for surgical management, although decision-making remains primarily guided by clinical severity of airway obstruction.