Measurement of absolute dimensions in endoscopic sinus surgery.

OBJECTIVE: To develop and evaluate a simple, noninvasive technique for the precise measurement of antrostomy dimensions using standard endoscopic views. METHODS: We produced an antrostomy probe and devised a method, on the basis of techniques of aerial planimetry, for measuring antrostomies using standardized endoscopic views. Ten shapes of known surface areas were measured independently by three experienced endoscopic sinus surgeons using 30 and 70 degree endoscopes. The accuracies of surgeon assessment and interobserver concordance were calculated. RESULTS: The three surgeons were able to calculate the surface areas with great precision (Pearson's coefficient of correlation > 0.85 in all cases) using both 30 and 70 degree endoscopes. An intraclass correlation coefficient of 0.92 was obtained, indicating a high degree of concordance between the measurements obtained by different surgeons. CONCLUSION: This technique shows considerable promise as a tool for precise measurement of antrostomy dimensions in both clinical and research settings.