The long-term cephalometric and respiratory outcomes of mandibular distraction osteogenesis in infants with Pierre Robin sequence

2015-05-01Background: Micrognathia presents in many craniofacial disorders and may have immediate and long-term effects on the neonatal airway. Airway obstruction is a critical condition that often requires immediate intervention—ranging from intubation to tracheostomy, and mandibular distraction osteogenesis. ❧ Objectives: 1) Evaluate long-term development—assessed by cephalometrics analysis—of Pierre Robin Sequence (PRS) patients that underwent mandibular distraction osteogenesis (MDO) to alleviate airway obstruction. 2) Identify changes in growth patterns in this patient population as compared to published age-matched norms and age-matched untreated PRS patients. 3) Identify respiratory changes through polysomnography. ❧ Patients and Methods: A retrospective chart review and analysis was performed following approval of the Institutional Review Board (IRB). The sample consisted of 12 non-syndromic PRS patients diagnosed with respiratory distress or respiratory failure (based on polysomnography data) that had undergone mandibular distraction osteogenesis at Children’s Hospital Los Angeles (Los Angeles, Calif.) PSG was performed to document any changes in status of the breathing disorder. Lateral cephalograms were taken and digitally traced using a Bjork analyses and USCF Cranio analysis, and growth comparisons were produced. ❧ Results: There was a statistically significant increase in gonial angle (ML/RL) of the Pierre Robin sequence patients treated with MDO (PRSMDO) compared to untreated PRS patients. The mandibular ramus length (Ar-GO) was significantly shorter, and mandibular body (Go-Gn) was significantly longer in PRSMDO patients. Chin prominence (SN-Pg) was greater in PRSMDO patients. Maxillomandibular sagittal relationship (ANB) in the tested sample had a statistically significant closer approximation. Upper face height (N-ANS), lower face height (ANS-Gn), maxillary length (Co-A), and mandibular length (Co-Gn) were all shorter with statistical significance. All other measurements showed no statistical significance. ❧ Conclusion: The candidates for early intervention with MDO represent the most severe micrognathia cases. Further study of these patients is needed to determine if the more vertical growth vector observed in these patients will lead to a dolichofacial profile as the patient matures. Should an extremely high gonial angle lead to an anterior skeletal and dental open bite paired with a non-pleasing soft tissue profile, these patients—once skeletally mature—may require two-jaw orthognathic surgery to address their facial disharmony