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In order to clarify the optimal liquid-solid ratio ( L/ S) values for the activation of metakaolin at different concentrations of phosphoric acid solution, five sets of phosphoric acid solution of 4, 5, 6, 7 and 8 mol•L-1 were set up, and four L/ S values of 0. 6, 0. 7, 0. 8 and 0. 9 were used for preparation of metakaolin-phosphoric acid based geopolymer (MPAG). The 7 and 28 d compressive and flexural strengths of MPAG were used as the evaluation indexes to investigate the effects of above preset variables on its mechanical properties. The compressive strength of samples corresponding to the optimal L/ S value concentration of each group after sulfate erosion were further investigated. Finally, the phase composition and microscopic morphology of MPAG were characterized and analyzed. The results show that MPAG is mainly composed of an amorphous aluminum phosphate phase. Greater compressive strength can be obtained by using L/ S value of 0. 6 when the concentration of phosphoric acid solution is 4 - 6 mol•L-1, and when the concentration increase to 7 - 8 mol•L-1, the recommended of L/ S value is 0. 7. MPAG exhibits good sulfate resistance, with a compressive strength retention rate of 84% to 93% after 28 d immersion. The samples prepared with 6 mol•L-1 phosphoric acid under any L/ S value achieved the maximum flexural strength for that L/ S value. The 28 d maximum flexural strength is 6. 80 MPa when L/ S value is 0. 6. The results of this study can provide references for the preparation and application of MPAG. [ABSTRACT FROM AUTHOR]

Endoscopic skull base surgery presents significant technical challenges and high surgical risks, requiring collaboration among multiple disciplines such as otolaryngology, neurosurgery, ophthalmology, and oral maxillofacial surgery. In recent years, there has been rapid development in endoscopic skull base surgery, characterized by flourishing anatomical research and an expanding range of surgical indications. The future brings both opportunities and challenges, and endoscopic skull base surgery must grasp new directions in medical development, actively providing patients with safer and more effective treatment options., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Objective: To assess the prognosis of sinonasal adenoid cystic carcinoma with hard palatine invasion treated by transnasal endoscopic total maxillectomy. Methods: Clinical data of twenty-six patients with sinonasal adenoid cystic carcinoma invading hard palatine treated by transnasal endoscopic total maxillectomy between May 2014 and December 2020 was analyzed retrospectively. Survival rate, local recurrence and distant metastasis were analyzed using Kaplan-Meier method. Cox regression was used to investigate the prognosis factors. Masticatory function after maxillectomy has also been assessed using the questionnaire of patients' satisfaction about masticatory function. Results: Margins in 8 patients（30%） were positive. The median time of follow-up was 38 months（6 to 85 months）. Twenty-five patients recurred. Four patients died of distant metastasis. The 5-year overall survival rate and relapse-free survival rate was 79.5% and 89.1%, respectively. Independent predictors of outcome on multivariate analysis were positive margin（ P =0.018）, recurrence（ P =0.006） and distant metastasis（ P =0.04）. Conclusion: Transnasal endoscopic total maxillectomy could be performed for the treatment of the sinonasal adenoid cystic carcinoma with hard palatine invasion. Positive margin, local recurrence and distant metastasis were important predictors for patients' prognosis., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.)

Objective: To evaluate the efficacy of endoscopic nasopharyngectomy in the management of recurrent nasopharyngeal cancers (NPC) and to identify the prognostic factors., Methods: Between January 2006 and March 2014, 71 patients who received endoscopic nasopharyngectomy for recurrent NPC were retrospectively reviewed. The sex and the age of the patients, T stage, and tumor necrosis were recorded. Correlation between clinicopathological features and survival time was analyzed. Kaplan-Meier analysis was used to calculate the disease overall survival, disease-specific survival, and disease-free survival rates. Cox multivariate regression analysis and ROC curve analysis were used to determine the predictive value of the parameters., Results: The median age of 71 patients with recurrent nasopharyngeal carcinoma was 51.0 years old. Male to female ratio was 2.9:1 (male: 53, female: 18). The lesions were staged as follows (AJCC, 2010, seventh edition): rT1, 27; rT2, 10; rT3, 19 and rT4, 15. All patients underwent successful endoscopic nasopharyngectomy. No patient was transferred to open approach. The mean operative time was 155 minutes. The average blood loss was 450 ml. Three patients needed intraoperative blood transfusion. No serious postoperative complications occurred. Postoperative follow-up time was 5-96 months. During follow-up, 48 cases survived, including that 7 patients survived with disease, 1 patient had pulmonary metastases, and 1 case had cervical lymph node metastasis. Two-year overall survival and disease-free survival rates were 74.0% and 60.5%, respectively. Five-year overall survival and disease-free survival rates were 39.0% and 31.9%, respectively. Multivariate analysis showed that tumor necrosis was an independent prognostic factor for survival in recurrent nasopharyngeal carcinoma patients (P=0.001)., Conclusion: Endoscopic nasopharyngectomy is a safe and effective procedure for the treatment of recurrent nasopharyngeal carcinoma.

Objective: To determine if greater efficacy could be achieved with the intranasal antihistamine azelastine and the intranasal corticosteroid fluticasone propionate used concurrently in the treatment of nasal obstruction of persistent non-allergic rhinitis., Method: A total of 162 persistent non-allergic rhinitis cases with moderate to severe nasal obstruction were randomized to treatment with the following: the combination therapy or nasal corticosteroids monotherapy. Efficacy was assessed by change from baseline in nasal obstruction score at week 2 and week 6 visits. The perceptions of global treatment satisfaction(convenience, side effects, cost and effectiveness) in both groups were analyzed., Result: In both groups, the nasal obstruction score assessment descended significantly at week 2 and week 6 visits versus at baseline (all P < 0.01). At week 2 and week 6 visits, the nasal obstruction score in the combination therapy groups were significantly improved than that in nasal corticosteroids monotherapy groups (all P < 0.01). The perceptions of global treatment satisfaction in the combination therapy groups were significantly better (P < 0.05)., Conclusion: Azelastine nasal spray and intranasal corticosteroid in combination may provide a substantial therapeutic benefit for patients with persistent non-allergic rhinitis, especially nasal obstruction. The combination therapy was well tolerated and safety.

Objective: To summarize the efficacy of Sorbalgon strips used in endoscopic sinus surgery (ESS), to explore a better nasal packing materials., Method: From Jan. 2000 to Apr. 2003., 2013 cases with Sorbalgon strips for nasal packing of nasal chronic sinusitis and polyps after endoscopic sinus surgery, and compared with packing of Aureomycin ointment gauze. The hemostasia effect and nasal cavity response were observed., Result: Sorbalgon strips had effectiveness at controlling hemorrhage in ESS. Comparing with aureomycin ointment gauze, Sorbalgon strips had less bleeding when being removed (P < 0.01), and the nasal cavity response was gentle (P < 0.01). The packing time with Sorbalgon strip was no more than 24 hour. No any adverse event was observed., Conclusion: Sorbalgon strips are a better nasal packing material used in ESS.

Objective: To investigate the effect of noise generated by the otologic drills and suctions on the cochlear of the operated and nonoperated ear., Method: To examine the noise generated by the different kind of drills and suctions in tympanoplasty, the ND10 Sound Level Meter (Beijing) was used. The bone-conduction thresholds was measured before and one month after operation respectively in both ears., Results: Sound pressure levels for the otologic drills and suctions were 82-106 dB and 71-84 dB, respectively. There was no statistically significant difference between pre-noise and one-month post-noise bone-conduction thresholds in both operated and nonoperated ears., Conclusion: It is safety to use otologic drills and suctions for the patients. There is no apparent harmful effect on the function of cochlear in both ears for the noise of using drills and suctions in tympanoplasty.

Objective: To investigate the accuracy and safety of the modified techniques in anterior skull base microsurgery with navigation system., Methods: Operation was performed upon 42 patients with benign and malignant tumor of anterior skull base involving both cerebral cranium and visceral cranium with the help of modified navigation system. A new arrangement was designed for stable maintenance of the headset with dynamic reference frame to avoid disturbance during emission of encoded infrared signal. Six reference points were used, distributed in the parietal, frontal, zygomatic, maxillary, and mastoid regions. The STN navigation system and SMN surgical microscope navigator were used to provide virtual pointer, virtual approach route and virtual contour as an orientation for stereotaxic guidance during surgery., Results: The modified technique could keep the accuracy of surgical guidance within 1 approximately 1.5 mm in comparison with the accuracy of 4 mm or more by the original design, thus guaranteeing the safety of surgery., Conclusion: The modified techniques raise the accuracy and safety of anterior skull base microsurgery. However, the cost remains high.

Objective: To investigate the value of nasal endoscopy in the surgery of the nasal inverted papillomas., Method: 29 patients with nasal inverted papilloma, 15 cases of them were applied nasal endoscopic surgery (nasal endoscopic surgery group), 14 cases were applied nasal lateral incision surgery(nasal lateral incision group), and compared the results of the two surgery., Result: Follow-up 1.8 years., Complications: nasal endoscopic surgery group(1 case) was obviously lower than nasal lateral incision group(5 cases), P < 0.01; The hospitalization time: nasal endoscopic surgery group(13.1 d) was obviously short than nasal lateral incision group(20.4 d), P < 0.01; The volume of blood during surgery(I-II stage): nasal endoscopic surgery group(175 ml) was obviously lower than nasal lateral incision group(525 ml), P < 0.01;, Conclusion: The nasal endoscopy was a better method for treating I-II stage nasal inverted papilloma, and the major advantage is an incision of the face can be avoided. As to III-IV stage disease, should be carefully selected endoscopic surgery. Nasal lateral incision surgery still was a safe and reliable therapeutic method.