Functional endoscopic sinus surgery (FESS) is the gold standard surgical intervention for management of patients with chronic rhinosinusitis (CRS). Synechiae formation in the middle meatus is the most common complication of endoscopic sinus surgery after FESS. Nasal debridement is a postoperative procedure used in the prevention of synechiae formation. This procedure lacks standardized evidence-based guidelines. The currently existing studies that have been conducted to determine the efficacy of post-operative debridement have shown conflicting results. We hypothesize that there is no difference in short and long term clinical outcomes between patients who had routine post-operative nasal debridement following FESS and patients who did not have post-operative nasal debridement.

Purpose The purpose of this study is to assess the efficacy of post-FESS nasal debridements in the prevention of post-operative synechiae formation.

Hypothesis There is no difference in short and long term clinical outcomes between patients who had routine post-operative nasal debridement following FESS and patients who did not have post-operative nasal debridement.

Justification To prevent synechiae formation, many studies have been published evaluating the efficacy of post-operative debridement procedures. Many of these studies have shown conflicting results. There were many inconsistent variables between the studies, such as limited follow-up periods, varying extent of surgery, and variability in pre and post-operative treatment.

With a well designed study, we would like to assess if there is a difference in the incidence of formation of middle meatal synechiae between patients who have debridement and patients who don't.

This will further add much needed evidence to the need for this procedure in the post operative period following FESS.

Surgery The participants in this study will all undergo standard-of-care functional endoscopic sinus surgery (FESS) to treat their sinus disease. No changes will be made to pre-operative or operative protocol on account of this study. All post-operative standard-of-care procedures and medication will be maintained.

Follow up visits After FESS, participant subjects will be asked to return for 4 follow-up visits within the first 90 days and one follow-up visit at 180 days. They will be asked to return at 6, 30, 60, 90 and 180 days following their sinus surgery. At their 6 and 30 day follow-up visits they will either receive or not receive routine post-operative debridement depending on randomization.

Statistical Analysis

Sample size calculations A sample size calculation was performed to determine the appropriate number of patients required to adequately compare the incidence of synechiae between participants with versus without postoperative debridement following FESS. Previous investigations at the St. Paul's Sinus Centre have found that of post-FESS cases, 18% develop synechiae from use of gloved-Merocel middle meatal spacers. Utilizing a type I error of 5%, type II error of 20%, effect difference of 15% and 10% loss to follow-up, a total of 150 patients are required (75 per arm).

Statistical Comparisons The primary objective of this randomized controlled trial will be to compare the incidence of synechiae between subjects receiving debridement versus those receiving saline irrigation (no debridement) up to 180 days post-surgery. Count and absolute percentages of synechia incidence will be reported. The Chi-Squared test will be used to determine statistical significance between incidence rates. Probability values less than 5% (α=0.05) will be considered significant. Corresponding odds ratios and 95% confidence intervals will be reported.

For the secondary outcome measures (e.g. Sinonasal Outcomes Test 22 SNOT-22, PJESS/MLK), results will be summated and considered as continuous, numerical variables. Descriptive statistics using mean, median, standard deviation and inter-quartile ranges will be reported. The unpaired two sample student t-tests will be applied to investigate the difference between the means of the various outcome measures. Probability values less than 5% (α =0.05) will also be considered statistically significant.

Baseline demographics and clinical factors will be compared between each treatment group to determine whether randomization yielded comparable groups. Multivariable logistic and linear regression will be used to investigate the relationship between postoperative debridement and the primary (incidence of synechiae) or secondary outcomes (PJESS/MLK).

Inclusion Criteria:

• Over the age of 19;
• Have chronic sinus disease (CRS) and are scheduled to undergo sinus surgery on both sides of your nose for the first time.

Exclusion Criteria:

• Unable to speak English;
• Are having surgery for the removal of a nasal tumor;
• Have a disorder of your immune system in which your body's immune system attacks itself (autoimmune disorder)
• Diagnosed with cystic fibrosis
• Have had sinus surgery in the past
• Are scheduled to have a procedure known as nasal septal reconstruction, without additional sinus surgery

All IPD that underlie results in a publication will be available to other researchers.

The patient will know if he/she is getting debridement or not. The PI will comment on all the objective outcome measures and will be the blinded assessor (he will not perform the debridements).