Effect of Probiotic Nasal Irrigation on the Postoperative Care of Chronic Rhinosinusitis

Chronic rhinosinusitis is a common chronic disease in otolaryngology, with a prevalence of approximately 20% in Taiwan. Patients often experience symptoms such as nasal congestion, runny nose, postnasal drip, and olfactory abnormalities, significantly impacting their quality of life. When drug treatment is ineffective, patients may require functional endoscopic sinus surgery to improve symptoms. However, proper postoperative care is often a crucial factor in the success of the surgery. Nasal irrigation is widely used to treat nasal and sinus diseases, with saline solution being the most commonly used irrigation fluid. However, recent studies have indicated that the nasal microbiome may be related to the inflammatory response in chronic rhinosinusitis; therefore, the application of probiotics as nasal irrigation additives has gradually attracted attention. Some studies suggest that certain probiotics may have the potential to regulate local immune responses and reduce inflammation. This study employs a prospective, randomized comparative study design. This study aims to enroll 120 patients undergoing functional endoscopic sinus surgery for chronic rhinosinusitis. One month post-surgery, patients will be randomly assigned to two groups: Group 1 (saline nasal irrigation group): Nasal irrigation with 240 mL of warm saline solution twice daily for eight weeks, supplemented with 3 g of maltodextrin as a placebo. Group 2 (probiotic nasal irrigation group): Nasal irrigation with 240 mL of warm saline solution containing 3 g of probiotic heat-killed probiotic LDL557 twice daily for eight weeks (concentration 10\^8 cfu/mL). The heat-killed probiotic LDL557 (Lactobacillus delbrueckii subsp. lactis LDL557) used in this study is a lactic acid bacteria strain screened from corn and developed by Taiwan Synbio Tech Co., Ltd. Two groups of subjects underwent questionnaire assessments, nasal endoscopy, olfactory testing, nasal function testing, nasal bacterial culture, and measurement of inflammatory markers of nasal irrigation fluid before and after nasal irrigation. This study aims to further evaluate the potential clinical benefits of probiotic nasal irrigation in the postoperative care of chronic rhinosinusitis, serving as a reference for future postoperative care models for chronic rhinosinusitis.