Airway Analysis in Apert Syndrome: The Role of Drug-Induced Sleep Endoscopy (2019)

Sir: We read with great interest the recent article by Forte et al entitled “Airway Analysis in Apert Syndrome.”1 The study was well planned, and we appreciate the effort made by the authors to shed light on this complex topic. However, we would like to clarify some points regarding upper airway assessment in this subgroup of patients. Craniofacial skeletal morphology plays an important role in the patency of the upper airway in both healthy children and children with craniofacial anomalies. Consequently, children with craniofacial conditions are generally at increased risk for developing respiratory compromise, especially during sleep. In particular, between 40 percent and 83 percent of children with syndromic craniosynostoses were found to have obstructive sleep apnea.2 Because long-term sequelae of obstructive sleep apnea in children are potentially serious, it is important to better understand the relationship between obstructive sleep apnea and craniofacial anomalies. The main factors that lead to obstructive sleep apnea in craniofacial syndromes appear to be midface and/or mandibular hypoplasia. Nevetheless, we should keep in mind that obstructive sleep apnea, despite strong correlation with unfavorable craniofacial anatomy that leads to a more collapsible airway during sleep, is often a multifactor disorder. Treating it with orthognathic surgery without further examination of its cause might lead to undertreatment or even mistreatment. Craniofacial dysmorphology correction can be effective in resolving airway obstruction, but in some cases, results have been somewhat less promising, with about 30 percent of children showing no improvement of the respiratory disorder.3 In addition, some studies have revealed a discrepancy between airway volume measurements and respiratory outcome. In some cases, surgery did not result in significant upper airway volume gain, while a distinct improvement of the respiratory status was observed. In other cases, despite volume increase of the upper airway, no respiratory improvement was shown.4 These data support the concept that upper airway volume measurements, as a whole, correlate well with respiratory outcome but are not always completely reliable. To what extent an increase in airway volume improves the dynamics of breathing in this subgroup of patients remains unclear. Over the past few years, attention has been drawn to identifying the site of upper airway obstruction in children with complex obstructive sleep apnea as in those with craniofacial malformations. Computed tomography scanning is one of the most common tools used to identify sites of upper airway obstruction in these children. Segmented structural analysis, as described by Forte et al., definitely permits us to analyze the complex anatomy of the complete upper airway in a detailed way with high reproducibility. Nevertheless, the measurements obtained represent a static reflection of a dynamic environment that may not accurately represent the dynamic upper airway collapse seen during sleep (respiratory impairment mainly occurs during sleep). We agree with the authors that individualized surgical planning, targeted at the site of obstruction, may provide an excellent success rate. Although few data are available in literature, drug-induced sleep endoscopy seems to be a promising tool for upper airway evaluation and treatment selection in children with craniofacial anomalies.5 One of the strengths of this technique is that drug-induced sleep endoscopy, by a direct view of the upper airway, can provide some insights into the location and pattern of dynamic airway obstruction. For these reasons, drug-induced sleep endoscopy may be recommended to identify the exact levels of obstruction and incorporate the findings in the treatment plan, thereby providing a way to better tailor management for obstructive sleep apnea in children with craniofacial anomalies. DISCLOSURE The authors have no financial interest to declare in relation to the content of this article. Ottavio Piccin, M.D., M.Sc.Department of Otolaryngology Head and Neck SurgeryS. Orsola-Malpighi University HospitalBologna, Italy Rossella Sgarzani, M.D., Ph.D.Department of EmergencyBurn CenterBufalini HospitalAzienda USL della RomagnaCesena, Italy Paolo G. Morselli, M.D.Department of Plastic and Reconstructive SurgeryAlma Mater Studiorum University of BolognaBologna, Italy