Role of Preoperative Radiological Assessment in Predicting Difficult Airway Management during General Anesthesia

Abstract

Background: Difficult airway management continues to be a significant cause of perianesthetic complications under general anesthesia. While conventional bedside airway exams are helpful, they may not be sufficient to detect internal anatomical abnormalities which can lead to difficult laryngoscopy and tracheal intubation. Radiological evaluation before surgery might be useful to provide objective parameters of airway structures, and help predict airway difficulty.

Objective: To evaluate the role of preoperative radiological airway assessment in predicting difficult airway management during general anesthesia.

Methods: This prospective observational study was conducted at Islamabad Diagnostic Centre, Islamabad, from January 2025 to June 2025 and included 85 adult patients undergoing elective procedures under general anesthesia with endotracheal intubation. The Mallampati classification, thyromental distance, sternomental distance, inter-incisor distance, neck circumference and cervical extension were performed as a part of the pre-operative clinical assessment of the airway. Radiological parameters measured were skin to epiglottis distance, tongue thickness, pre-epiglottis space, hyomental distance, hyomental distance ratio and mandibular length. Intraoperative airway difficulty was evaluated by Cormack–Lehane grade, number of intubations, intubation time, first-pass success and need for adjunct airway devices. The predictive performance was calculated using ROC curve analysis and multivariable logistic regression.

Results: Difficult airway management was observed in 19 (22.4%) patients, while 66 (77.6%) had an easy airway. Patients with difficult airways had significantly greater skin-to-epiglottis distance (25.8 ± 3.6 vs 20.4 ± 3.2 mm; p < 0.001) and tongue thickness (59.3 ± 6.1 vs 52.1 ± 5.7 mm; p < 0.001), together with lower hyomental distance and hyomental distance ratio. Skin-to-epiglottis distance showed the highest predictive accuracy, with an AUC of 0.86, sensitivity of 84.2%, and specificity of 80.3% at a cut-off of >23.5 mm. Tongue thickness and hyomental distance ratio showed AUCs of 0.82 and 0.80, respectively. Increased skin-to-epiglottis distance, increased tongue thickness, and Mallampati class III–IV remained independent predictors of difficult airway management.

Conclusion: Preoperative radiological assessment can provide valuable objective information for prediction of difficult airway management. Skin-to-epiglottis distance showed the strongest predictive ability and may be particularly useful when combined with conventional bedside airway examination.