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.

Level Of Evidence: 2b.