I. Executive Summary Background The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS.

Background Endoscopic skull‐base surgery (ESBS) is employed in the management of diverse skull‐base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull‐base surgery have produced the International Consensus Statement on Endoscopic Skull‐Base Surgery (ICAR:ESBS). Methods Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence‐based review or evidence‐based review with recommendations format. Subsequently, each topic was written and then reviewed by skull‐base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus. Results The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull‐base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated. Conclusion A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence‐based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull‐base community to embrace these opportunities and collaboratively address these shortcomings.

Complications of endoscopic sinus surgery still occur 25 years after the initial introduction of the surgery in 1985. Many complications can be managed without a bad outcome. The key to prevention is knowledge of anatomy, preparation, anticipation, and experience. Even then, complications can occur in the most experienced hands. Patients most at risk for complications include those with revision surgery, extensive disease, skull base anatomic or radiologic variations or dehiscences related to disease or previous surgery, and the use of powered instrumentation.

This study presents the sinonasal microbiome profile in one of the larger populations of non-CRS and CRS subjects, and is the first office-based cohort in the literature. In contrast to healthy, AR, and CRSwNP subjects, CRSsNP MM samples exhibited decreased microbiome diversity and anaerobic enrichment. CRSsNP MM samples had reduced diversity compared to same-subject IM samples, a novel finding.

Objective To develop a clinical consensus statement on the use of balloon dilation of the eustachian tube (BDET). Methods An expert panel of otolaryngologists was assembled with nominated representatives of general otolaryngology and relevant subspecialty societies. The target population was adults 18 years or older who are candidates for BDET because of obstructive eustachian tube dysfunction (OETD) in 1 or both ears for 3 months or longer that significantly affects quality of life or functional health status. A modified Delphi method was used to distill expert opinion into clinical statements that met a standardized definition of consensus. Results After 3 iterative Delphi method surveys, 28 statements met the predefined criteria for consensus, while 28 statements did not. The clinical statements were grouped into 3 categories for the purposes of presentation and discussion: (1) patient criteria, (2) perioperative considerations, and (3) outcomes. Conclusion This panel reached consensus on several statements that clarify diagnosis and perioperative management of OETD. Lack of consensus on other statements likely reflects knowledge gaps regarding the role of BDET in managing OETD. Expert panel consensus may provide helpful information for the otolaryngologist considering the use of BDET for the management of patients with OETD.

Oral steroids are strongly recommended for short-term management of CRSwNP. Oral steroids are also recommended for management of AFS. Oral steroid use in CRSsNP is optional due to insufficient strong evidence. Oral steroids are also strongly recommended in the perioperative period for CRSwNP and AFS. There is no recommendation for oral steroids use in the perioperative period in patients with CRSsNP. The risks of oral steroids are rare, but significant adverse effects must be considered.

Equivalent numbers of men and women underwent ESS for CRS. Overall, women electing ESS had higher total SNOT-22 scores and lower Lund-Mackay CT scores than men. Women reported more problems with postnasal drainage (CRS overall, CRSsNP, and CRSwNP), embarrassment (CRS overall and CRSwNP), and facial pain (CRSwNP). Gender differences in CRS are poorly understood and merit further study.

All CRS subtypes demonstrated clinically meaningful improvement in postoperative SNOT-22 scores following ESS. Our overall revision ESS rate was 4% (3.5% in CRSwNP). AFS, AERD, and EGPA groups demonstrated low revision rates, while immunodeficiency and GPA patients required more revision surgery. A contemporary understanding of CRSwNP subtypes facilitated surgical and medical strategies in improving outcomes for AERD, AFS, and EGPA patients. CRSsNP subtypes with immunodeficiency and GPA merit further investigation to optimize outcomes.