The Journal
In patients who underwent bilateral mandibular distraction ( n = 6 ), statistically significant increase in the measurement of airway space occurred at the level of the soft palate ( mean 4.18mm ), at the level of the tongue ( mean 4.17mm ) and at the level of the 2nd cervical vertebra ( mean 2.25mm ). In patients who underwent unilateral mandibular distraction , statistically significant increase in the measurement of the airway space occurred at the level of the soft palate ( mean 3.22mm ) and at the level of the 2nd cervical vertebra ( mean 3.14mm ).
Discussion
The evolution of distraction osteogenesis to correct jaw size discrepancy via surgical intervation has multiple effects on orofacial
[ 6,9 ]
complex . The pharyngeal airway space has been studied by various techniques such as cephalometric radiography , endoscopic e x a m i n a t i o n , C T s c a n , M R I a n d polysomnography and each method has been shown to have its own advantages and
[ 9-13 ]
disadvantages . Cephalometric analysis of the airway allows precise measurements to be taken in the sagittal plane at anatomically well defined homologous landmarks , but it does not provide transverse dimensions due its twodimensional nature . In spite of the obvious limitations of cephalometric analysis , it remains the most popular technique in the evaluation of airway space because of ease of procurement , availability , low cost and minimal radiation exposure .
Changes in dimensions of the airway have been demonstrated in literature after surgical repositioning of the mandible and have been used to advantage in the management of
[ 9 ]
obstructive sleep apnea as well . Obstructive sleep apnea ( OSA ) has been associated with collapse and blockage of the upper airway behind the tongue base ( oro-pharyngeal airway ) and the soft palate ( the velo-pharyngeal region ) .
Variations in mandibular and craniofacial anatomy such as increased cranial base length , increased lower facial height , posteriorly positioned tongue and inferior position of the
[ 5 ]
hyoid bone have been associated with OSA . Mandibular distraction osteogenesis has been shown to improve upper airway obstruction in children and neonates , and has been adopted as a treatment modality in patients with problems in the airway space [ 8 ]. Most studies have evaluated the alteration in the airway clinically , with Polysymnography and use of
[ 9,14,15 ] endoscopy .
Keeping in mind the different levels of airway compromise that may occur in patients , the cephalometric measurements in this study were conducted at multiple levels including the soft palate , the tongue , the hyoid bone , the epiglottis and the 2nd and 4th cervical vertebrae .
Subjective clinical improvement in the airway status of our patients was evaluated and has been reported elsewhere [ 16 ].
Cepahlometric evaluation and CT scan analysis done by Rachmiel et al ( 2012 ) demonstrated advancement of the hyoid bone along the axis of the mandibular body after distraction osteogenesis [ 11 ]. Ananthnarayanan and Manikandhan ( 2013 ) conducted cephalometric analysis of 5 patients who underwent mandibular distraction osteogenesis to show increase in the airway space with an average of 3mm increase in upper and lower pharyngeal dimensions [ 17 ]. In our study , cephalometric measurements confirmed the statistically significant increase in measurements of the oro-pharyngeal airway at all five levels of evaluation .
Conclusion
Our findings have demonstrated that there is measurable increase in the dimensions of the oro-pharyngeal airway at multiple anatomic
55 Vol . 14 No . 1 Jan-Apr 2018