[Conventional vs. CT Data-Based Three-Dimensional Measurement of Nasal Septum Defects]

Septal perforations can severely diminish quality of life. Where surgical closure is impossible, due to size, location or contraindications, septum obturators offer an alternative. Defect anatomy can be assessed two ways: analog via silicone impression, or digitally using preoperative CT scans. This study compares these two methods.Retrospective analysis of 500 patients with symptomatic septal perforations was carried out, including defect size and location, type of closure and closure rate in surgical closures. 19 patients qualified for comparison of defect size and shape determined by conventional impression with CT-based data. For high precision comparison, silicone impressions were converted into plaster models, then digitally scanned, and CT data was converted into 3D models.The analysis of the NSD in the 19 patients and the comparison of the results from analog silicone impressions and preoperative CT scans revealed deviations of less than 10% in 8 out of 19 cases and less than 20% in 13 out of 19 cases. The deviations tended to be smaller in cases of larger defects. Larger deviations were observed when there were longer time intervals between the impression and the CT scan.Measurements of NSD based on CT data yield similar results to those obtained from silicone impressions, particularly when the CT scans are performed in close temporal proximity and in cases of larger defects. Further clinical studies should investigate whether iSOs created from CT data result in comparable clinical patient acceptance.