Abtin Tabaee, MD, Editor

Edward D. McCoul, MD, MPH, Editor

No other aspect of rhinologic care for inflammatory disease represents a greater challenge to our field than refractory CRS, defined as persistent symptoms and objective inflammatory findings despite medical and surgical therapy. The negative quality-of-life impact, disease morbidity, and health care utilization for these patients are disproportionate and costly. Although our understanding of the underlying reasons for treatment failure has previously been limited, we are now approaching meaningful diagnostic and treatment pathways for many of these patients. The current issue of Otolaryngologic Clinics of North America explores refractory CRS from both pathophysiologic and clinical perspectives.

An esteemed list of authors has provided a series of complementary articles that both summate the latest advances in the field and provide a framework for approaching a patient with currently available modalities. The issue commences with a discussion of classification for the different CRS subtypes and how this may translate to a personalized approach to treatment. Subsequent articles discuss the various pathophysiologic factors that may exist in patients with refractory CRS, including dysregulated microbiome, genetic factors, biofilm, inflammatory injury, osteitis, and systemic disorders. The final portion of the issue explores different types of treatment modalities, including office-based, medical, and surgical options. Practical applications of these treatments as well as supporting clinical research studies are presented. Common to any discussion of an emerging field, there are as many questions in flux as there are well-defined principles.

We are immensely grateful to our publishing team for the opportunity to guest-edit this issue and to the contributing authors for their expertise and dedication in writing a series of deeply meaningful discussions and practical approaches to the care of patients with refractory CRS. Their collective wisdom is the core of this discussion. It is our hope that this issue will serve as a reference for clinical rhinology practice and as a reflection of both the current understanding and the future directions in the field.