Current understanding of allergic fungal rhinosinusitis and treatment implications:

Surgical Navigation in the Anterior Skull Base Using 3-Dimensional Endoscopy and Surface Reconstruction

Importance

Image guidance is an important adjunct for endoscopic sinus and skull base surgery. However, current systems require bulky external tracking equipment, and their use can interrupt efficient surgical workflow.

Objective

To evaluate a trackerless surgical navigation system using 3-dimensional (3D) endoscopy and simultaneous localization and mapping (SLAM) algorithms in the anterior skull base.

Design, Setting, and Participants

This interventional deceased donor cohort study and retrospective clinical case study was conducted at a tertiary academic medical center with human deceased donor specimens and a patient with anterior skull base pathology.

Exposures

Participants underwent endoscopic endonasal transsphenoidal dissection and surface model reconstruction from stereoscopic video with registration to volumetric models segmented from computed tomography (CT) and magnetic resonance imaging.

Main Outcomes and Measures

To assess the fidelity of surface model reconstruction and accuracy of surgical navigation and surface-CT model coregistration, 3 metrics were calculated: reconstruction error, registration error, and localization error.

Results

In deceased donor models (n = 9), high-fidelity surface models of the posterior wall of the sphenoid sinus were reconstructed from stereoscopic video and coregistered to corresponding volumetric CT models. The mean (SD; range) reconstruction, registration, and localization errors were 0.60 (0.24; 0.36-0.93), 1.11 (0.49; 0.71-1.56) and 1.01 (0.17; 0.78-1.25) mm, respectively. In a clinical case study of a patient who underwent a 3D endoscopic endonasal transsphenoidal resection of a tubercular meningioma, a high-fidelity surface model of the posterior wall of the sphenoid was reconstructed from intraoperative stereoscopic video and coregistered to a volumetric preoperative fused CT magnetic resonance imaging model with a root-mean-square error of 1.38 mm.

Conclusions and Relevance

The results of this study suggest that SLAM algorithm-based endoscopic endonasal surgery navigation is a novel, accurate, and trackerless approach to surgical navigation that uses 3D endoscopy and SLAM-based algorithms in lieu of conventional optical or electromagnetic tracking. While multiple challenges remain before clinical readiness, a SLAM algorithm-based endoscopic endonasal surgery navigation system has the potential to improve surgical efficiency, economy of motion, and safety.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

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.

Image-Guided Surgery and Intraoperative Imaging in Rhinology: Clinical Update and Current State of the Art

INTRODUCTION

Image-guided surgery (IGS) has gained widespread acceptance in otorhinolaryngology for its applications in sinus and skull base surgery. Although the core concepts of IGS have not changed, advances in image guidance technology, including the incorporation of intraoperative imaging, have the potential to enhance surgical education, allow for more rigorous preoperative planning, and aid in more complete surgery with improved outcomes.

OBJECTIVES

Provide a clinical update regarding the use of image guidance and intraoperative imaging in the field of rhinology and endoscopic skull base surgery with a focus on current state of the art technologies.

METHODS

English-language studies published in PubMed, Cochrane, and Embase were searched for articles relating to image-guided sinus surgery, skull base surgery, and intraoperative imaging. Relevant studies were reviewed and critical appraisals were included in this clinical update, highlighting current state of the art advances.

CONCLUSIONS

As image guidance and intraoperative imaging systems have advanced, their applications in sinus and skull base surgery have expanded. Both technologies offer invaluable real-time feedback on the status and progress of surgery, and thus may help to improve the completeness of surgery and overall outcomes. Recent advances such as augmented and virtual reality offer a window into the future of IGS. Future advancements should aim to enhance the surgeon's operative experience by improving user satisfaction and ultimately lead to better surgical results.

Fungal Pneumonia in The Immunocompetent Host: A Possible Statistical Connection Between Allergic Fungal Sinusitis with Polyposis and Recurrent Pulmonary Infection Detected by Gastroesophageal Reflux Disease Scintigraphy

Objectives:

Fungal pneumonia in the immune competent host is a rarity with few reported cases in the literature. We present a series of 7 cases of recurrent fungal pneumonia in association with allergic fungal rhinosinusitis and gastroesophageal reflux disease (GERD). We hypothesised that recurrent infection may have been transported from the infected paranasal sinuses into the lung by GERD as the process was terminated by surgical fundoplication in 2 of these patients.

Methods:

Patients were recruited into the study if they were immune competent and had recurrent fungal pneumonia and GERD. Allergic fungal rhinosinusitis was proven by biopsy. GERD was investigated by a scintigraphic test that assessed local oesophageal disease, lung aspiration and head and neck involvement with a hybrid gamma camera and X-ray computed tomography.

Results:

All patients were shown to have GERD with 5/7 showing paranasal sinus contamination and 7/7 showing laryngopharyngeal involvement and 6/7 lung aspiration. One patient had characteristics strongly predictive of aspiration. Fundoplication led to cessation of fungal lung infection in two patients.

Conclusion:

Recurrent fungal pneumonia in the immune competent host should raise the possibility of re-infection from the paranasal sinuses, especially in patients with GERD.

Immunomodulators in chronic rhinosinusitis

Objective

To provide new insight into how chronic rhinosinusitis (CRS) is conceptualized and treated with a focus on immunomodulator therapy.

Data sources

Pubmed, Medline, and Embase.

Methods

A current review of the evidence is provided for immunomodulators investigated for treatment of CRS with nasal polyps (CRSwNP).

Results

Biologic therapies targeting IgE, IL-4, IL-5, and IL-13 for the treatment of CRSwNP have shown promise and are currently in phase 3 trials. Anti-immunoglobin E (IgE) therapy with omalizumab was assessed in 6 studies, anti-interleukin (IL)-5 therapy in 3 studies (2 mepolizumab, 1 reslizumab) and anti IL-4/IL-13 (dupilumab) therapy in one study. Studied outcomes varied, but the majority of trials identified clinical benefit of therapy over placebo. Other potential targets include thymic stromal lymphopoetin (TSLP), IL-25, IL-33, and sialic acid-binding immunoglobulin-type lectin (Siglec)-8. Small molecule drugs that target the dysregulation of the immune system in CRS are also being investigated for their immunomodulatory effects on inflammation.

Conclusion

Immunomodulator therapies for CRS currently in development will likely provide another therapeutic option for patients who have severe disease unresponsive to corticosteroids and surgery. Targeted monoclonal antibody therapies have shown encouraging results and phase 3 trials are underway. IL-4/IL-13 inhibition has shown the most promise to date. Further larger, well-designed trials are needed to improve understanding of these molecules and to offer endotype-driven therapies in the management of CRS. None of these therapeutics have shown long-term immunomodulation when discontinued and therefore further investigation into the pathomechanism of disease continues to be needed.

Allergic Fungal Sinusitis Caused by Exserohilum rostratum and Literature Review

A case of allergic fungal sinusitis (AFS) caused by Exserohilum rostratum, proven by culture and histopathology of the biopsy material, is described. The identity of the isolate was confirmed by sequencing of ITS region of rDNA. To the best of our knowledge, this is the first report of allergic E. rostratum sinusitis from Kuwait and Arabian Peninsula. Ten previously described cases of AFS have been reviewed. The report highlights the emerging importance of E. rostratum as a human pathogen in this region and role of molecular methods in its accurate identification.

Allergic Aspergillus Rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) is a unique variety of chronic polypoid rhinosinusitis usually in atopic individuals, characterized by presence of eosinophilic mucin and fungal hyphae in paranasal sinuses without invasion into surrounding mucosa. It has emerged as an important disease involving a large population across the world with geographic variation in incidence and epidemiology. The disease is surrounded by controversies regarding its definition and etiopathogenesis. A working group on "Fungal Sinusitis" under the International Society for Human and Animal Mycology (ISHAM) addressed some of those issues, but many questions remain unanswered. The descriptions of "eosinophilic fungal rhinosinusitis" (EFRS), "eosinophilic mucin rhinosinusitis" (EMRS) and mucosal invasion by hyphae in few patients have increased the problem to delineate the disease. Various hypotheses exist for etiopathogenesis of AFRS with considerable overlap, though recent extensive studies have made certain in depth understanding. The diagnosis of AFRS is a multi-disciplinary approach including the imaging, histopathology, mycology and immunological investigations. Though there is no uniform management protocol for AFRS, surgical clearing of the sinuses with steroid therapy are commonly practiced. The role of antifungal agents, leukotriene antagonists and immunomodulators is still questionable. The present review covers the controversies, recent advances in pathogenesis, diagnosis, and management of AFRS.

Otopolyposis With Middle Ear Allergic Mucin in a Patient With Allergic Fungal Rhinosinusitis

OBJECTIVE

The purpose of this study is to report a case of otopolyposis and middle ear allergic mucin in a patient with allergic fungal rhinosinusitis (AFRS) and no history of middle ear disease and introduce these as possible otologic manifestations of the AFRS.

METHODS

A case of a 31-year-old female with the aforementioned findings is reported. A review of the pertinent literature was performed.

RESULTS

We report a case of a 31-year-old female with a history of AFRS but no history of middle ear disease or hearing loss who presented to our institution complaining of aural fullness. Physical exam was significant for middle ear masses of unknown etiology. Surgical exploration revealed the presence of allergic mucin and middle ear polyposis histologically identical to tissue sampled during prior sinonasal surgeries at the same institution. Aspiration of the middle ear space did not resolve the otologic symptoms.

CONCLUSION

Otopolyposis and middle ear allergic mucin are extremely rare but possible otologic manifestations of AFRS. We encourage otolaryngologists to consider this in the clinical differential diagnosis of patients with a history of AFRS with new onset otologic symptoms.

Overview of Frontal Sinus Pathology and Management

The frontal sinus is the most complex of all paranasal sinuses. Given its proximity to the cranial vault and orbit, frontal sinus pathology can progress to involve these structures and lead to significant morbidity, or even mortality. Surgical management of the frontal sinus is technically challenging. Various open and endoscopic surgical techniques are available to the otolaryngologist. This article presents an overview of the major disease entities that affect the frontal sinus, with a special emphasis on treatment principles and surgical management.

Prevalence of confirmed asthma varies in chronic rhinosinusitis subtypes

BACKGROUND

Chronic rhinosinusitis (CRS) and asthma describe inflammation of the upper and lower airway, respectively. Not surprisingly, the prevalence of CRS and asthma has been linked, with up to 50% asthma prevalence in CRS with nasal polyposis (CRSwNP) patients. However, these prevalence rates do not address subtypes of CRSwNP including allergic fungal rhinosinusitis (AFRS). This study sets out to objectively determine asthma prevalence in CRS subtypes prospectively.

METHODS

A prospective prevalence study of adult CRS patients was conducted over a 1-year period at a tertiary care center. Patients were grouped into CRSwNP, CRS without nasal polyposis (CRSsNP), or AFRS. Patients were administered the Asthma Screening Questionnaire (ASQ) and asthma was confirmed by pulmonary function testing (PFT) if positive on the ASQ. Chi square analysis was performed to compare the asthma prevalence among the CRS subtypes.

RESULTS

A total of 410 patients (age 48.1 ± 16.4; 53.5% male) were included. Of these, 178 (43.4%) had CRSwNP, 166 (40.5%) had CRSsNP, and 66 (16.1%) met criteria for AFRS. Analysis revealed that 48.3% of CRSwNP patients, 16.5% of CRSsNP patients, and 23.6% of AFRS patients had asthma confirmed by PFTs. Chi square analysis showed a significant difference in asthma prevalence between CRSwNP and AFRS (p = 0.0016) and CRSwNP and CRSsNP (p = 0.0000), but no significant difference between CRSsNP and AFRS (p = 0.2380).

CONCLUSION

There is a significant difference in the prevalence of asthma between CRSwNP and AFRS, suggesting a fundamental distinction in their etiologies despite similar immunologic profiles. Further efforts to delineate these biological disparities are underway.

Proallergic cytokines and group 2 innate lymphoid cells in allergic nasal diseases

Recent advances in our understanding of proallergic cytokines and group 2 innate lymphoid cells (ILC2s) indicate their critical roles in type 2 immunity-mediated disorders. Proallergic cytokines, interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin, are released from epithelial cells in inflamed tissues and drive type 2 inflammation by acting on innate and acquired immune systems. ILC2s are an innate immune population that responds to proallergic cytokines by producing type 2 cytokines. In line with allergic disorders in the lung, skin, and intestine, emerging evidence suggests the involvement of proallergic cytokines and ILC2s in allergic nasal diseases such as chronic rhinosinusitis with polyps (CRSwNP), allergic fungal rhinosinusitis, and allergic rhinitis (AR). In CRSwNP patients, both proallergic cytokine levels and ILC2s frequency are increased in the nasal mucosa. Increased proallergic cytokine levels correlate with poorer disease outcomes in CRSwNP. Levels of nasal proallergic cytokines are also elevated in AR patients. In addition, animal studies demonstrate that cytokines are essential for the development of AR. It is becoming clear that the proallergic cytokine/ILC2s axis participates in allergic diseases by multiple mechanisms dependent upon the inflammatory context. Thus, a thorough understanding of these cytokines and ILC2s including their tissue- and disease-specific roles is essential for targeting the pathways to achieve therapeutic applications.

In vitro anti-yeast activity of chloramphenicol: A preliminary report

Chloramphenicol is a bacteriostatic antimicrobial agent but its antifungal activity is not known. The present study aimed to investigate the activity of chloramphenicol against 30 representative yeasts. The antimicrobial assay of chloramphenicol (50mg/mL; 100mg/mL and 200mg/mL) was determined by the disc diffusion method using Mueller-Hinton agar against 30 representative yeast strains. Zone of inhibition was read after 48-72h incubation at 37°C and results were compared with some standard antifungal agents. Most of the tested yeasts (73.3%) showed inhibition zones (5 up to 35mm) to chloramphenicol impregnated discs (200mg/mL). Three out of the four tested Candida albicans as well as Candida famata, Candida glabrata, Candida haemolonei and Cryptococcus neoformans showed no inhibition zones to chloramphenicol (200mg/mL). Caspofungin acetate (50mg/mL) inhibited 83.3% of the strains; ketoconazole (200mg/mL) 70% and metronidazole 10%. Chloramphenicol discs: 50 and 100mg/mL showed less activity (6.7% and 36.7%, respectively) compared to the 200mg discs; whereas chloramphenicol (BBL; 3μg/mL) inhibited 13.3% of the strains. The anti-yeast activities of chloramphenicol were comparable to other known antifungal compounds. Moreover, it is cheap, has fewer side effects and its inclusions in selective fungal media such as Mycosel have to be questioned.