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Introduction: The depth of anterior cranial fossa was described by Keros in the year 1962. It is used for traumatic risk assessment during endoscopic surgery involving anterior skull base by ENT Surgeons. The purpose of this study is to measure the length of the lateral lamella, the angle formed by the lateral lamella and the horizontal plane passing through the cribriform plate on CT PNS and to correlate it with Keros Classication. Material and Methods: A retrospective observational study was carried out by review of CT-Scan of Paranasal sinus of patients above 18 years from November 2019 to October 2021. The lateral lamella (LL) length, the angle formed by the lateral lamella and the horizontal plane passing through the cribriform plate and the depth of the olfactory fossa was measured by viewing the DICOM images of the CT scan. Results: A total of 102 CT Scan of Paranasal sinuses of patients were assessed. The length of lateral lamella was greater in males compared to females. There were no signicant differences in the lateral lamella length between each side. The most common type of angle was Class II (88.7%), followed by Class III (6.9 %) and Class I (4.4%). When the depth of the cribriform fossa was assessed by Keros classication, type I (63.7%) was the commonest presentation followed by Keros type II (36.3%). A strong correlation was found between types of Keros and lateral lamella length (Pearson coefcient = 0.679), which was found to be statistically signicant [p-value - 0.0005]. In this study, we noted that there were gender and sidewise variations on Keros classication. Conclusion: Lateral lamella length and angle formed by the lateral lamella and the horizontal plane passing through the cribriform plate is as important as the depth of olfactory fossa. An acute angle increases the risk of injury to skull base during endoscopic sinus surgery. |
