Preoperative clinical predictors of difficult laryngeal exposure for microlaryngoscopy : the laryngoscore

Objectives/Hypothesis To identify a clinical predictor score for difficult laryngeal exposure (DLE) during operative microlaryngoscopy. Study Design Prospective cohort study in two academic institutions. Methods We evaluated 319 patients before microlaryngoscopy for benign and malignant glottic diseases by a standardized preoperative assessment protocol (Laryngoscore) that included 11 parameters: interincisors gap (IIG), thyro-mental distance, upper jaw dental status, trismus, mandibular prognathism, macroglossia, micrognathia, degree of neck flexion-extension, history of previous open-neck and/or radiotherapy, Mallampati's modified score, and body mass index (BMI). Each parameter was assessed to obtain a total score. Patients were divided into five classes according to the anterior commissure (AC) visualization: class 0, complete AC visualization with large-bore laryngoscopes in the Boyce-Jackson position; class I, as class 0 with external laryngeal counterpressure; class II, as class I in the flexion-flexion position; class III, as class II using small-bore laryngoscopes; and class IV, impossible AC visualization. Results Class 0-I-II (good/acceptable laryngeal exposure) presented a median score < 6. This value was chosen as cutoff for distinguishing favorable versus difficult/impossible laryngeal exposures. When the Laryngoscore was < 6, good laryngeal exposure was observed in 94% of patients, whereas when ≥ 6, DLE was encountered in 40%. When considering a Laryngoscore of ≥ 9, 67% of patients had a DLE. At univariate analysis, IIG, upper jaw dental status, macroglossia, micrognathia, degree of neck flexion-extension, and BMI statistically impacted on DLE (P < 0.05). Conclusions The Laryngoscore is a good predictor of DLE and assists in selecting the ideal candidates for operative microlaryngoscopy.