THE INTUBATION CHALLENGE: COMPARING MODIFIED MALLAMPATI SCORE AND THYROMENTAL DISTANCE
DOI:
https://doi.org/10.71000/51ckcs42Keywords:
Difficult intubation, Mallampati score, Thyromental distance, Anesthesia, Elective surgery, Airway management, Anesthesia, , Preoperative assessmentAbstract
Airway management is a cornerstone of safe anesthesia practice, and failure to anticipate a difficult airway can result in life-threatening complications. The Modified Mallampati Score (MMS) and Thyromental Distance Test (TMDT) are among the most widely used preoperative predictors. However, when used individually, their predictive accuracy remains variable. Combining these tests may improve diagnostic performance and support safer airway management in surgical patients.
Objective: To evaluate and compare the sensitivity, specificity, and predictive values of MMS and TMDT individually and in combination for predicting difficult intubation in apparently normal patients undergoing elective surgery.
Methods: This comparative observational study enrolled 150 patients with ASA physical status I or II scheduled for elective procedures under general anesthesia. Preoperative airway assessment was performed using MMS and TMDT, with Cormack–Lehane (CL) grading during laryngoscopy serving as the gold standard. Demographic data, surgical specialty, intubator experience, and the use of special equipment were recorded. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each test and their combination.
Results: MMS showed a sensitivity of 42.3%, specificity of 92.0%, PPV of 52.3%, and NPV of 88.4%. TMDT had a sensitivity of 23.07%, specificity of 92.0%, PPV of 37.5%, and NPV of 85.1%. The combined use of MMS and TMDT improved specificity to 98.4%, PPV to 66.7%, and maintained a high NPV of 84.8%, though sensitivity decreased to 15.4%. Difficult intubations were more frequent in females (80.8%) and general surgery cases (100%), while the use of special equipment was significantly associated with difficulty (p = 0.000).
Conclusion: While neither MMS nor TMDT alone offers both high sensitivity and specificity, their combined use enhances diagnostic accuracy and should be considered a valuable component of routine preoperative airway assessment.
References
Moslemi F, Khan ZH, Alizadeh E, Khamnian Z, Eftekhar N, Hosseini MS, et al. Upper lip bite test compared to modified Mallampati test in predicting difficult airway in obstetrics: A prospective observational study. J Perioper Pract. 2023;33(4):116-21.
Kaul R, Singh D, Prakash J, Priye S, Kumar S, Bharati. Ultrasound Guided Measurement of Anterior Neck Tissue for the Prediction of Difficult Airway: A Prospective Observational Study. Rom J Anaesth Intensive Care. 2021;28(2):105-10.
Martínez-García A, Guerrero-Orriach JL, Pino-Gálvez MA. Ultrasonography for predicting a difficult laryngoscopy. Getting closer. J Clin Monit Comput. 2021;35(2):269-77.
Kharrat I, Achour I, Trabelsi JJ, Trigui M, Thabet W, Mnejja M, et al. Prediction of difficulty in direct laryngoscopy. Sci Rep. 2022;12(1):10722.
Dawood AS, Talib BZ, Sabri IS. PREDICTION OF DIFFICULT INTUBATION BY USING UPPER LIP BITE, THYROMENTAL DISTANCE AND MALLAMPATI SCORE IN COMPARISON TO CORMACK AND LEHANE CLASSIFICATION SYSTEM. Wiad Lek. 2021;74(9 pt 2):2305-14.
Narra LR, Udongwo N, Dominic JL, Doreswamy S, Bhasir A, Elkherpitawy I, et al. Obesity and the Other Independent Predictors in Elective Endotracheal Tube Intubations: A Narrative Review. J Clin Med Res. 2022;14(5):177-87.
Schwartz A. A New Old Way to Look at Airway Assessment. Aana j. 2022;90(2):87-9.
Emik E, Gümüs-Özcan F, Demirgan S, Selcan A. Evaluation of the correlation between preoperative airway assessment tests, anthropometric measurements, and endotracheal intubation difficulty in obesity class III patients undergoing bariatric surgery. Medicine (Baltimore). 2021;100(36):e27188.
Mahmoud M, Hasanin AM, Mostafa M, Alhamade F, Abdelhamid B, Elsherbeeny M. Evaluation of super-obesity and super-super-obesity as risk factors for difficult intubation in patients undergoing bariatric surgery. Surg Obes Relat Dis. 2021;17(7):1279-85.
Saoraya J, Vongkulbhisal K, Kijpaisalratana N, Lumlertgul S, Musikatavorn K, Komindr A. Difficult airway predictors were associated with decreased use of neuromuscular blocking agents in emergency airway management: a retrospective cohort study in Thailand. BMC Emerg Med. 2021;21(1):37.
Bektaş H, Göksu S, Şen E. A Comparison of the Effectiveness of Videolaryngoscopy and Macintosh Laryngoscopy in Intubation Attempts on Adult Patients. Turk J Anaesthesiol Reanim. 2022;50(5):352-7.
Senol D, Ozbag D, Dedeoglu N, Cevirgen F, Toy S, Ogeturk M, et al. Comparison of anthropometric and conic beam computed tomography measurements of patients with and without difficult intubation risk according to modified mallampati score: New markers for difficult intubation. Niger J Clin Pract. 2021;24(11):1609-15.
Bala R, Budhwar D, Kumar V, Singhal S, Kaushik P, Sharma J. Clinical and ultrasonographic assessment of airway indices among non-pregnant, normotensive pregnant and pre-eclamptic patients: a prospective observational study. Int J Obstet Anesth. 2023;54:103637.
Selvi A, Ozayar E, Turksal E, Kurtay A, Kucuk O. Can chin-nape circumference and the ratio of neck circumference to chin-nape circumference predict difficult mask ventilation or difficult intubation in obese patients? Medicine (Baltimore). 2023;102(50):e36614.
Goranović T, Milić M, Nesek Adam V, Šimunjak B. ASSESSMENT OF STANDARD ANTHROPOMETRIC AIRWAY CHARACTERISTICS RELEVANT FOR AIRWAY MANAGEMENT OF PATIENTS WITH OBSTRUCTIVE SLEEP APNEA SYNDROME DURING SLEEP BREATHING DISORDER SURGERY: A RETROSPECTIVE, SINGLE CENTER STUDY. Acta Clin Croat. 2023;62(Suppl1):21-8.
Dawood AS, Talib BZ, Sabri IS. Prediction of Difficult Intubation By Using Upper Lip Bite, Thyromental Distance and Mallampati Score in Comparison To Cormack and Lehane Classification System. Wiad Lek. 2021;74(9 cz 2):2305–14.
Kopanaki E, Piagkou M, Demesticha T, Anastassiou E, Skandalakis P. Sternomental distance ratio as a predictor of difficult laryngoscopy: A prospective, double-blind pilot study. Anesth Essays Res. 2020;14(1):49.
Pathak L, Sah PK. Prediction of difficult intubation in apparently normal patients by combining modified mallampati test and thyromental distance: A prospective observational study. Int J Anesthesiol Sci. 2020;2(1):16–20.
Sen B, Mitra M, Kundu K, Basu M. Diagnostic Accuracy of Modified Mallampati Test (MMP) and Thyromental Distance Test (TMD) in Predicting Difficult LaryngoscopyA Comparative Study in a Tertiary Care Teaching Hospital in India. J Evid Based Med Healthc. 2020;7(28):1379–84.
De Luis-Cabezón N, Ly-Liu D, Renedo-Corcostegui P, Santaolalla-Montoya F, Zabala-Lopez de Maturana A, Herrero-Herrero JC, et al. A new score for airway assessment using clinical and ultrasound parameters. Front Med. 2024;11(February):1–10.
Chhabra AR, Thannappan S, Iyer HR. Preoperative ultrasonographic evaluation of the airway vis-à-vis the bedside airway assessment to predict potentially difficult airway on direct laryngoscopy in adult patients—a prospective, observational study. Ain-Shams J Anesthesiol [Internet]. 2023;15(1).
Abdelhady BS, Elrabiey MA, Abd Elrahman AH, Mohamed EE. Ultrasonography versus conventional methods (Mallampati score and thyromental distance) for prediction of difficult airway in adult patients. Egypt J Anaesth [Internet]. 2020;36(1):83–9.
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Amir Khan, Immad Ul Islam, Zabih Ullah, Muhammad Abdullah Saleem, Muhammad Rizwan, Syed Numan Shah, Faheem Ullah, Ahmad Ullah (Author)
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
