Computed Tomography-Based Exploration of Infundibular Anatomy for Maxillary Sinus Balloon Dilation

Objectives: A clinically relevant reconstruction of the ethmoid infundibulum and maxillary sinus ostium was developed to use 3-dimensional computed tomographic (CT) imaging technology and measurement software in an effort to better understand the anatomy of the maxillary sinus ostium and to optimize the maxillary sinus balloon dilation technique. Methods: A retrospective review was performed of reconstructed high-resolution CT scans of patients from a private otolaryngology practice who underwent imaging for evaluation of sinus disease using multiplanar reconstruction software. The CT scans were retrospectively obtained from patients who presented for evaluation of chronic sinus disease and were analyzed with quantitative multiplanar reconstruction software that allowed measurements to be computed in clinically meaningful planes. Results: Data were obtained from 31 sinuses on 18 CT scans. The mean anteroposterior distance from the guidewire exit to the maxillary ostium was 3.5 mm, and the mean optimal guide trajectory ("clocking") angle was 17.5 degrees from the pure axial plane (95% confidence interval, 12.58 degrees to 22.48 degrees). The curvilinear guidewire travel distance was 6.9 mm from the guidewire exit to the ostial entry. Conclusions: This study reveals specific anatomic information that is applicable to the technique of transnasal maxillary sinus balloon catheter dilation. The data collected allow surgeons to anticipate the direction in which a guidewire must be manipulated in order to correctly enter the maxillary ostium. According to the data, a gentle anterior retraction of the uncinate process and a starting guide orientation 18 degrees from pure lateral will best facilitate maxillary sinus ostial access. Application of the readily available software used for this study affords the opportunity to predict the location of the natural ostium within the infundibulum before operation and customize the technique to each specific patient.