Computed Tomographic Evaluation of Asymmetric Ethmoid Roof in Chronie Paranasal Sinusitis

Abstract

Background: Inadvertent violation of the fovea ethmoidalis resulting in cerebrospinal fluid (CSF) leakage is among the most potentially serious complications of endoscopic sinus surgery (ESS). We evaluated the incidence and degree of asymmetry in the ethmoid roof on patients diagnosed with paranasal sinusitis who had undergone ESS. Methods: From January 1994 to July 2002, 765 patients diagnosed with chronie paranasal sinusitis underwent computed tomography (CT) examination. Retrograde analysis of coronary CT scan sections were performed. The height and contour of bilateral ethmoid roofs were evaluated. Results: Contour asymmetry between bilateral ethmoid roofs with flattening on one side was found in 75 (9.8%) of the 765 patients. Right side flattening was noted in 55 patients (73.3%) and left side flattening was reported on 20 patients (26.7%). Difference in height between bilateral ethmoid roots was demonstrated in 280 patients. The fovea ethmoidalis was higher on the right side in 80 patients (28.6%) and on the left side in 200 patients (71.4%). 60th the contour and height were analyzed by chi-squared test. Significant differences in the contour and height of the right and left ethmoid roofs were noted (P＜ 0.001). Conclusion: Asymmetric height of the ethmoid roof was noted in nearly half of the CT scans on patients with paranasal sinusitis. Coronal CT scan allows comparison of the characteristics between bilateral ethmoid roofs. Preoperative review of the paranasal sinus scans and during performance of endoscopic sinus surgery could provide valuable guidance for the surgeon; hence, decreasing possible iatrogenic trauma.