Discussion
submucosal congestion, thyromental, dysphonia, SAD, cough, glottis fissure, trauma
In this trial, we demonstrated that the iSLN block was more effective in lowering the severity of POST, reducing swallowing discomfort and subsequent cough after elective gynecological surgery. Moreover, bilateral iSLN block also yielded a better effect on voice function.Multiple interventions were used to decrease POST in previous research, such as NSAIDs administration, local anesthetics lubrication [POST caused by SAD could be the result of direct trauma by rigid materials inserted into the upper airway, physical tensile stresses imposed by the cushions or gel [The iSLN provides sensory innervation of the mucosa surrounding the pharynx above glottis fissure [The iSLN is considered as a pure sensory nerve to predominantly supply the pharyngeal structure close to vocal cord [Postoperative dysphonia has been reported after SAD insertion [Duration of anesthesia was correlated with POST. Studies have shown that mechanical ventilation for more than 1.5 h can cause submucosal congestion and damage in the larynx [Difficult airway has the potential to modify the occurrence of POST. Neck circumference, thyromental distance and interincisor distance are used to predict the probability of difficult airway. A higher thyromental distance, to our common knowledge, provides a better condition for SAD insertion, and hence reduces the probability of POST. The thyromental distance of the included patients in the trial was 62-80 mm, whereas thyromental distance less than 60 mm was generally considered to be a risk factor for difficult intubation. Thus it failed to gain the correlation between neck circumference, thyromental distance, interincisor distance and POST in the trial. In addition, the presence of bloody sputum during extubation is resulted from pharyngeal trauma. Nonetheless, our study failed to detect the association with POST.