Quantification of Mandibular Morphology in Pierre Robin Sequence to Optimize Mandibular Distraction Osteogenesis

Abstract

Background: Mandibular distraction osteogenesis (MDO) is the primary surgical intervention to treat airway obstruction in Pierre Robin sequence (PRS). Current morphologic studies of PRS mandibles do not translate into providing airway management decisions. We compare mandibles of infants with nonsyndromic PRS to controls characterizing morphological variances relevant to distraction. We also examine how morphologic measurements and airway grades correlate with airway management. Methods: Patients with PRS under 2 months old were age and sex matched to controls. Demographic and perioperative data, and Cormack-Lehane airway grades were recorded. Computed tomography scans were used to generate mandibular models. Bilateral condylions, gonions, and the menton were identified. Linear and angular measurements were made. Wilcoxon rank sum and 2-sample t tests were performed. Results: Twenty-four patients with PRS and 24 controls were included. Seventeen patients with PRS required MDO. PRS patients had shorter ramus heights (16.7 vs 17.3 mm; P = .346) and mandibular body lengths (35.3 vs 39.3 mm; P < .001), more acute gonial angles (125.3° vs 131.3°; P < .001), and more obtuse intergonial angles (94.2° vs 80.4°; P < .001) compared to controls. No significant differences were found among patients requiring MDO versus conservative management nor among distracted patients with high versus low airway grades. Conclusion: Our study examines the largest and youngest PRS population to date regarding management of early airway obstruction with MDO. Our findings indicate that univector mandibular body distraction allows for normalization in nonsyndromic patients with PRS, and airway obstruction management decisions should remain clinical.

Laryngoscopy Grade Improvement and Difficult Airway Resolution in Infants With Robin Sequence Undergoing Mandibular Distraction Osteogenesis: A Multi-Institutional Study

“…Notably, the improvement in DLG did not always correlate with the severity of micrognathia when classified by measuring maxillomandibular discrepancy on computed tomography. Similar observations have been made in the literature for baseline mandibular characteristics and laryngoscopic findings (Volk et al, 2020). Most recently, Heffernan et al (2019) reviewed 22 infants with RS who underwent MDO at Boston Children's Hospital.…”

Loss of Extreme Long-Range Enhancers in Human Neural Crest Drives a Craniofacial Disorder

“…A Hotelling test again revealed that the ramus was the mandibular structure most affected by changes in Sox9 dosage ( Figure 6 N). Although milder, these alterations in mandibular ramus morphology are reminiscent of phenotypes observed in PRS patients, as quantified by a number of studies ( Bienstock et al., 2016 ; Chen et al., 2015 ; Chung et al., 2012 ; Suri et al., 2010 ; Susarla et al., 2017 ; Volk et al., 2020 ; Zellner et al., 2017 ; Table S4 ; Figure S6 C). Finally, to address whether enhancer knockout results in failure to thrive, we weighed pups up to weaning age (P20–P25) and detected a reduction in weight gain for mEC1.45 knockout animals ( Figure 6 O).…”

The Impact of Neonatal Mandibular Distraction on Long-Term Mandibular Growth and Morphology

“…15,18 Multiple studies to date have characterized the RS mandible, both pre-and post-distraction, but the majority have provided only short and intermediate-term data. [15][16][17]22,23 The present study adds to this growing body of literature by providing novel long-term morphologic data on the distracted and conservatively managed RS mandible.…”