Rhinogoniometer: Validation of an Instrument for Rhinoplasty

The position of the lower lateral cartilages is directly related to good nasal functionality. When these cartilages exhibit cephalic malposition, the angle of divergence between cartilages is usually less than 60 degrees, which can cause external nasal valve insufficiency. The objective of this study was to validate the rhinogoniometer, an innovative surgical instrument that allows for diagnosing the position of this cartilage intraoperatively. In the intraoperative period, the angle of divergence, which is the angle formed between the two lateral branches of the lower lateral cartilages, was measured in 31 primary rhinoplasty patients. The rhinogoniometer measurement was compared with that of the computerized analysis, and the reproducibility of measurements with the rhinogoniometer between two different surgeons was determined. When comparing the values obtained by the two methods, a significant difference was found (p = 0.034). On average, the angles measured by the rhinogoniometer were 3.7 degrees smaller than the measurements made by the software. It was observed that when the angles measured by both methods were above 75 degrees, the differences between the two measurements were higher (p = 0.022). However, for angles up to 75 degrees, the measurement using the rhinogoniometer was, on average, 0.79 degrees higher than the measurement taken by the software. When the difference in angles obtained by the two methods between different surgeons was evaluated, there was a significant difference (p < 0.023). In conclusion, at angles up to 75 degrees, the rhinogoniometer showed a negligible difference of 0.79 degrees higher than the measurement obtained via software. Measurements with the rhinogoniometer were also shown to be reproducible with different surgeons.