Objective: To establish a New Zealand rabbit animal model of laryngopharyngeal reflux disease (LPRD) using esophageal balloon together with metal internal stent dilation and to investigate the changes of mucosa. Methods: 20 New Zealand rabbits were randomly divided into experimental group and control group, with 10 in each group. Balloon dilatation and metal internal stent dilation were carried out in experimental group to reproduce the animal model of LPRD.The middle of balloon was placed at the lower esophageal sphincter (LES) while the stent was placed at the upper esophageal sphincter (UES). The guide wire was placed in the control group, but the balloon was not expanded and the stent was not placed. The general condition, pH value of hypopharynx, laryngeal histopathology and changes of pepsin content of New Zealand rabbits were observed regularly. The difference between experimental group and control group was compared. Results: The 24-hour Dx-pH monitoring results showed that the number of reflux episodes(20.0[9.5, 35.0], 13.0[6.5, 22.0]), and the percent time below pH 5.5 (1.36%[0.60%, 4.57%], 1.36%[0.43%, 2.77%]) in the experimental group at the 2nd and 4th week were significantly different from those in the control group (0[0,3.0], 1.0[0.5, 3.8]; 0[0, 0.01%], 0[0, 0], respectively, all P<0.01), suggesting that the experimental group New Zealand rabbits developed LPRD. Compared with the control group under microscope, lymphocytes infiltration and submucosal gland hyperplasia increased in the mucosa of the throat of the experimental group. The results of pepsin immunohistochemical staining between the two groups were statistically significant (P=0.014). Conclusion The use of balloon dilatation of the LES combined with metal stent dilatation of the UES can successfully establish a laryngopharyngeal reflux model, and lesions in the throat tissue can be observed.

Objective: To investigate the pathogenic factors of vocal leukoplakia and its clinical and pathological features. Methods: Eighty-one patients with vocal cord leukoplakia who underwent surgery between February 2010 and December 2016 and 160 volunteers without pharyngeal symptoms designed as controls were included in this case control study. The clinicopathological characteristics of 81 patients were summarized and analyzed synthetically. Results: There was statistical significance in reflux symptom index(RSI), reflux finding score(RFS), smoking index, and drinking index between case group and control group(Z=-5.35, -4.82, -4.76, -2.44, P<0.05). The voice-using duration per day in case group was significantly longer than that of control group.There was no statistical significance in hospital anxiety and depression scale for anxiety(HADA) scores、hospital anxiety and depression scale for depression(HADD) scores between case group and control group(P>0.05). In 42 patients who received 24-hour dual probe pH monitoring the prevalence of pathologic LPR was 42.8%. In 81 patients, 39(48%)patients were pathologically diagnosed as squamous cell hyperplasia, 18(22%)patients as mild dysplasia, 12(15%)sides as moderate dysplasia , 10(12%)patients as severe dysplasia and 2(2%)patients as carcinoma in-situ. The average age of high-risk pathological vocal leukoplakia was significantly higher than that of low-risk leukoplakia(t=-2.73, P<0.01). The propotion of speckled leukoplakia in high-risk leukoplakia was significantly higher than that of low-risk leukoplakia(χ²=23.81, P<0.01). There was no statistical significance between high-risk leukoplakia and low-risk leukoplakia in the prevalence of pathologic LPR(P>0.05). The bilateral lesions, speckled leukoplakia were more likely to relapse(χ²=4.27, 12.17, P<0.05). The more serious the pathology, the more likely it was to relapse (Z=-2.168, P=0.03). There was no statistical significance between recurrence group and non-recurrence group in the prevalence of pathologic LPR(P>0.05). Conclusions LPR, smoke constitute the risk factors of vocal cord leukoplakia. Drinking, voice abuse are related to vocal cord leukoplakia. Senile, speckled leukoplakia are more likely to be malignancy. A speckled leukoplakia, bilateral leukoplakia, severe pathological degree are important factors to predict recurrence.