Predicting Difficult Laryngeal Exposure And Postoperative Pain With Suspension Laryngoscopy

Direct laryngoscopy is the most predominantly used technique in laryngology, with thefulcrum-based laryngoscope serving as the most popular instrument. But in someinstances difficult laryngeal exposure (DLE) may be still one of the chief problems tolaryngologists in microlaryngosurgery.ObjectiveTo identify physical findings that can be standardized to predict the presence of difficultlaryngeal exposure (DLE) and analysis of the relation of the postoperative throat painwith the time and pressure acting on laryngopharynx and tongue base during asuspension laryngoscopy.MethodFifty patients underwent a microlarygosurgery were included in this prospectivestudy.The following13parameters that may probably predict DLE including: age, sex,modified Mallampati index (MMI), body mass index (BMI), neck circumference, fullmouth opening, sternum-mental distance (SMD), thyroid-mental distance (TMD),hyoid-mental distance (HMD), horizontal thyroid-mental distance (HTMD), verticalthyroid-mental distance (VTMD), thyroid-mandible angle (TMA) and full neckextension angle (NEA) were preoperatively examined in fifty patients. Duringendotracheal intubation and suspension laryngoscopy, Cormack-lehane score, laryngealexposure scores, time to achieve laryngeal exposure, and the time and pressure actingon laryngopharynx and tongue base were obtained and compared with the postoperativethroat pain grade.ResultBMI≥25(p=.028), TMD<6at full neck extension position (p=.033) were reliable predictors of DLE in Chinese mainland patients. Both the time to achieve laryngealexposure (mean,1.96±1.28minutes) and the pressure acting on laryngopharynx andtongue base (mean,292±109mmHg) increased in the DLE patients.22patients (44%)complained a feeling of postoperative throat pain, while it was not the pressure (p=.971),but the duration of suspension laryngoscopy (mean,39±31minutes) had the significantcorrelation with the throat pain grade (p=.021).ConclusionBMI, and TMD at full neck extension position could be used as predictors of DLE inChinese mainland. The pressure acting on the laryngopharynx and tongue base during asuspension rigid laryngoscopy was one of the major inducers of the postoperative throatpain, however, it seemed to have no significant correlation with the pain grade.