A Comparative Study of Acromio-Axillo-Suprasternal Notch Index with Modified Mallampati Grading and Thyromental Distance in Predicting Difficult Visualization of Larynx

Abstract

Introduction:
Difficult laryngoscopy and intubation pose significant risks in anaesthetic practice. Traditional airway assessment tools like Modified Mallampati Grading (MMG) and Thyromental Distance (TMD) show variable predictive accuracy. The Acromio-Axillo-Suprasternal Notch Index (AASI) is a newer anatomical index that evaluates upper thoracic and cervical alignment and may offer better prediction of difficult visualization of the larynx (DVL). This study compared AASI with MMG and TMD in predicting DVL.

Materials and Methods:
A prospective observational study was conducted on 60 adult patients (18–60 years), ASA I and II, undergoing elective surgeries under general anaesthesia requiring endotracheal intubation. Preoperative assessment included AASI, MMG, and TMD. Cormack-Lehane grading during laryngoscopy served as the reference standard, with Grades III and IV defined as DVL. Statistical analysis included chi-square tests, logistic regression, and ROC curve analysis using SPSS .

Results:
DVL was observed in 13.33 of patients. AASI  showed significant association with and was an independent predictor  AASI demonstrated sensitivity of 75, specificity of 96, accuracy of 93, and AUC . In contrast, TMD and MMG had lower sensitivities  respectively) and were not statistically significant predictors.

Conclusion:
AASI outperformed MMG and TMD in predicting difficult laryngoscopy. Being simple, objective, and highly accurate, AASI should be considered for routine preoperative airway assessment.