Background: Postoperative infections following endoscopic sinus surgery (ESS) impair wound healing and lead to poor outcomes. The aim of this study is to assess the effectiveness of Chitogel to reduce postoperative infections and restore a healthy microbiome following ESS. Methods: In this double-blinded randomized control trial, 25 patients undergoing ESS were prospectively recruited. At the end of surgery, patients were randomized to receive Chitogel to one side of the sinuses (allowing the other side to serve as control). Patients underwent routine follow-up with nasoendoscopies performed at 2, 6, and 12 weeks postoperatively. Sinus ostial measurements, microbiology, and microbiome swabs from bilateral sides were collected intraoperatively and at 12 weeks postoperatively. Additional swabs were collected if infection was present.Results: Improved endoscopic appearance of the sinuses (p = 0.03) and ostial patency were noted on the Chitogel side compared with control at 12 weeks (p < 0.001). A significant decrease in infections on the Chitogel side (12.0%) compared with control (52.0%) (p = 0.005) was evident. Following the use of Chitogel, there was a significant increase in the combined relative abundance of commensals Corynebacterium and Cutibacterium (Propionibacterium) from 30.15% at baseline to 46.62% at 12 weeks compared with control (47.18% to 40.79%) (p.adj = 0.01). Conclusion:Chitogel significantly improved both the nasoendoscopic appearance of the sinuses and sinus ostial patency at 12 weeks postoperatively. Chitogel used following ESS helps restore an improved microbiome resulting in an increase in the relative abundance of commensals Corynebacterium and Cutibacterium (Propionibacterium). A significant decrease in postoperative infections was noted following use of Chitogel.

Oral squamous cell carcinoma (OSCC) is the 8th most common cancer globally with an incidence rate of 18 per 100 000 per annum in Australia. 1,2 Surgery forms the primary treatment of OSCC. 3 Risk stratification in deciding on the need for adjuvant therapy after resection of the primary OSCC is based on the presence of adverse histologic features such as extracapsular spread (ECS), close/involved margins, lymphovascular involvement (LVI), perineural involvement (PNI) and lymph node metastases. [4][5][6] Perineural invasion is defined when at least one of the two histologic features is present. Either tumour cells need to be present in any of the three layers of the nerve sheath or they need to encircle at least 33% of the circumference of a nerve. 7 Although PNI is generally acknowledged to be a negative prognostic factor, there is conflicting evidence in the literature regarding its association with recurrence and overall survival. [8][9][10][11][12][13][14][15][16] In the study by Crachiolo et al, 10 PNI-positive OSCC tumours were associated with decreased disease-specific survival (DSS) but not associated with differences in local or regional control rates. Liao et al 12 found that presence of PNI was not associated with decreased local control or overall survival.Currently, PNI is reported as being either absent or present, without any general consensus on classifying the type and extent of PNI.Evidence in the literature suggests that histopathologic subcategories

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