Aim: To evaluate the use of cone-beam computerized tomography (CBCT) for upper airway analysis. Subsequently, to use CBCT to assess volumetric changes in the pharyngeal airway space (PAS) after orthognathic surgery (particularly advancement procedures).
Materials and methods: A systematic review (SR) of the literature concerning upper airway analysis using CBCT was performed. A PubMed search (January 9th, 2011) yielded 382 papers of which 46 were considered relevant. These were classified according to their focus. Secondly, a retrospective analysis of 30 patients who underwent orthognathic surgery at the Institute of Maxillofacial Surgery and Implantology of Teknon Medical Center (Barcelona) was performed. Three groups comprising 10 patients each were established as follows:
Bimaxillary surgery (maxillomandibular advancement);
maxillary advancement; and
mandibular advancement. CBCT scans were taken pre and postoperatively and processed using SimPlant Pro Crystal (Materialise, Leuven).
Results: According to the SR, three-dimensional analysis of the PAS using CBCT is accurate and reliable, although important methodological discrepancies exist. Volumetric analysis of our clinical sample revealed an average percentage increase of 69.8% in group 1, 37.7% in group 2 and 78.3% in group 3 ( p < 0.05).
Conclusion: The advent of CBCT has provided the opportunity to precisely assess the PAS with an accessible, low-radiation scan. Important obstacles remain, including the definition of precise anatomical boundaries and the influence of tongue position, mandible morphology and respiration phase. Our preliminary clinical results suggest the influence of mandibular advancement on PAS volume is greater than the effect of the forward movement of the maxilla.
Conflict of interest : None declared.