Reliability of the Cormack-Lehane Classification: A Scoping Review

Abstract

We aimed to find and describe studies estimating the reliability of the Cormack-Lehane and modified Cormack-Lehane classifications, using the kappa statistic (kappa). We performed a scoping review searching PubMed as well as Google Scholar and Google.com (gray literature) between October 2024 and January 2025 for published studies without date or language restrictions reporting a kappa for Cormack-Lehane grades between at least two raters. We screened 825 records in PubMed and 1,200 in the gray literature of which 15 articles ultimately met our inclusion criteria. Most studies used still images (n=6) and pre-recorded videos (n=8) obtained from a direct (n=5), video (n=5), or fiberoptic (n=4) laryngoscopy (one used both direct and video) performed by clinicians from multiple specialties on patients in the operating room (n=8), simulation (n=2), office (n=3), and prehospital (n=1) settings (one unknown). Studies examined both the Cormack-Lehane classification (n=10) and the modified classification (n=6). Inter-rater reliability ranged from slight to almost perfect, kappa from 0.020 to 0.888. The evidence examining the reliability of the Cormack-Lehane and modified Cormack-Lehane classifications is limited with heterogeneous methods and results.