Background: The modified Mallampati (MMP) classification is a standard method of oropharyngeal evaluation for predicting difficult laryngoscopy. Previous studies have demonstrated that the predictive value of the MMP is improved when thepatient’s craniocervical junction is extended rather than neutral (Extended Mallampati Score, EMS). In the present study, we compared the predictive value of the MMP, EMS and thyromental score in the obese. Methods: We performed a prospective study of adult patients with a Body Mass Index (BMI) 40 comparing the MMP and EMS. The performance of the MMP, EMS, and thyromental distance was compared forthe ability to predict difficult laryngoscopy, defined as a Cormack­Lehane grade of 3 or 4. Positioning and direct laryngoscopic techniques were not standardized. Results: Hundred patients with a BMI >35 were evaluated withboth the MMP and EMS and received direct laryngoscopy. On average, craniocervical extension decreased the MMP class. Compared to the MMP, the EMS improved specificity and predictive value while maintaining sensitivity. Compared to the MMP and thyromental distance, an EMS thyromental distance, an EMS class of 3 or 4 were statistically significant predictors of difficultlaryngoscopy in the obese. There was no difference in the incidence ofdifficult laryngoscopy or intubation in the obese compared to patientswith a BMI >35. Conclusions: The EMS was Superior to the MMP in the Prediction of Difficult; Laryngoscopy in the Obese Population.

Keywords: Modified Mallampathi; Extended Mallampathi; Thyromental Distance; Cormac Lehane Grading; Obesity