The aim of this study is to determine what the ideal frequency of high-volume sinonasal saline irrigation in the early postoperative period following ESS for medically refractory CRS. We will evaluate once, twice, and three times daily frequency sinonasal saline irrigation protocols. Our hypothesis is that three times a day sinonasal saline irrigations for the first week is ideal with no difference between frequencies after 1 week.

Chronic Rhinosinusitis (CRS) is a common inflammatory condition of the upper respiratory tract lasting more than 8 to 12 weeks. Major symptoms include facial congestion/fullness, facial pain/pressure, nasal obstruction/blockage, purulent nasal drainage, and reduction or loss of smell. The diagnosis must include two major symptoms and either endoscopic evidence of polyps, edema or mucopurulent discharge from the middle meatus and/or CT changes in the mucosa of sinuses or ostiomeatal complexes.

CRS has an estimated prevalence of 5% in the Canadian population, and up to 16% in some adult populations in the United States. Sinusitis is associated with a major societal health care burden, costing billions of dollars a year in North America. The medical treatment of CRS includes topical saline and corticosteroid sprays, systemic steroids and antimicrobials. Specifically, sinonasal saline irrigation is a safe, nonpharmacologic treatment, and an important and efficacious component in the management of CRS. Sinonasal saline irrigation can vary by concentration (e.g. hypertonic, isotonic, hypotonic), pressure (e.g. passive or active), and volume (e.g. high and low).

A recent evidence-based review by Rudmik et al. recommended sinonasal saline irrigation in the early postoperative period following endoscopic sinus surgery. Although 'daily' sinonasal saline irrigations are recommended, the ideal frequency is unknown since there have been no studies evaluating this topic.

This is a prospective, randomized, single blind study evaluating the subjective and objective outcomes of different sinonasal saline irrigation frequencies in patients who receive ESS for medically refractory CRS. Both disease-specific quality of life (QoL) and endoscopy scores will be measured at 1 week, 3 weeks, and 2 months postoperatively. The expected total number of patients to be enrolled in this study is approximately 75 (25 per arm), with a planned completion time of two years.

Inclusion Criteria:

• Adult patients with a diagnosis of CRS as per guidelines (> 18 years old)
• Documented failed medical treatment of CRS
• Planned ESS for the treatment of CRS
• Able to read and understand English

Exclusion Criteria:

• Pregnant
• Cystic Fibrosis
• Diagnosed immotile cilia syndrome
• Diagnosed immunodeficiency syndrome
• Diagnosed fungal sinusitis
• Sinonasal tumours or obstructive lesions