Recovery of olfaction after sinus surgery for chronic rhinosinusitis: A review

Olfactory Loss in Rhinosinusitis: Mechanisms of Loss and Recovery

Chronic rhinosinusitis (CRS) is a highly prevalent disease and up to 83% of CRS patients suffer from olfactory dysfunction (OD). Because OD is specifically seen in those CRS patients that present with a type 2 eosinophilic inflammation, it is believed that type 2 inflammatory mediators at the level of the olfactory epithelium are involved in the development of this olfactory loss. However, due to the difficulties in obtaining tissue from the olfactory epithelium, little is known about the true mechanisms of inflammatory OD. Thanks to the COVID-19 pandemic, interest in olfaction has been growing rapidly and several studies have been focusing on disease mechanisms of OD in inflammatory conditions. In this paper, we summarize the most recent data exploring the pathophysiological mechanisms underlying OD in CRS. We also review what is known about the potential capacity of olfactory recovery of the currently available treatments in those patients.

Type 2 and Non-type 2 Inflammation in the Upper Airways: Cellular and Molecular Alterations in Olfactory Neuroepithelium Cell Populations

PURPOSE OF REVIEW

Neurogenesis occurring in the olfactory epithelium is critical to continuously replace olfactory neurons to maintain olfactory function, but is impaired during chronic type 2 and non-type 2 inflammation of the upper airways. In this review, we describe the neurobiology of olfaction and the olfactory alterations in chronic rhinosinusitis with nasal polyps (type 2 inflammation) and post-viral acute rhinosinusitis (non-type 2 inflammation), highlighting the role of immune response attenuating olfactory neurogenesis as a possibly mechanism for the loss of smell in these diseases.

RECENT FINDINGS

Several studies have provided relevant insights into the role of basal stem cells as direct participants in the progression of chronic inflammation identifying a functional switch away from a neuro-regenerative phenotype to one contributing to immune defense, a process that induces a deficient replacement of olfactory neurons. The interaction between olfactory stem cells and immune system might critically underlie ongoing loss of smell in type 2 and non-type 2 inflammatory upper airway diseases. In this review, we describe the neurobiology of olfaction and the olfactory alterations in type 2 and non-type 2 inflammatory upper airway diseases, highlighting the role of immune response attenuating olfactory neurogenesis, as a possibly mechanism for the lack of loss of smell recovery.

Delivering Therapy to the Olfactory Cleft: A Comparison of the Various Methods of Administering Topical Nasal Medications

Background and objective Chronic rhinosinusitis (CRS) is an inflammatory condition affecting the nasal mucosa, and it causes olfactory dysfunction (OD) in up to 78.2% of patients. Corticosteroids are the mainstay of treatment to shrink nasal polyposis, reduce inflammation, and improve olfactory function. While many delivery methods for topical nasal corticosteroids exist, there is scarce data on the efficacy of the various medication delivery methods to the olfactory cleft (OC). In light of this, this study aimed to compare the following delivery methods to the OC: conventional nasal spray (NS), nasal drops in the Kaiteki position (KP), and exhalation delivery system (EDS). Methods We evaluated 16 sinonasal cavities from eight cadaver specimens in this study. Each sinonasal cavity was administered fluorescein dye solution via NS, KP, and EDS. Following administration, nasal endoscopy was employed to capture staining patterns in the OC. OC staining was rated with scores ranging from 0 (no staining) to 3 (heavy staining) after each administration of dye solution. Mean OC staining ratings were calculated and compared using the Kruskal-Wallis rank sum test and the Wilcoxon signed-rank test. Results The mean OC staining score for the different delivery methods was as follows - NS: 1.095 ± 1.008, EDS: 0.670 ± 0.674, and KP: 2.038 ± 1.097. Nasal drops in the KP had a significantly higher staining score compared to NS (p=0.041) and EDS (p=0.003). However, there was no significant difference in staining scores between NS and EDS. Conclusions Nasal drops in the KP are more effective at reaching the OC than NS or EDS and should be considered as a first-line modality for administering topical medications when treating OD.

Surgery for chronic rhinosinusitis with nasal polyps: An update

This update aimed to evaluate surgical indications in the management of chronic rhinosinusitis with nasal polyps (CRSwNP). It was conducted and reported according to the criteria stipulated by the Synthesis Without Meta-analysis (SwiM) guidelines. From the PubMed-National Library of Medicine database, 1098 articles were identified for the period 2006-2021 using the key words "nasal polyps" and "surgery". After screening and analysis, 39 publications were selected. The efficacy of surgery on functional improvement in CRSwNP, measured by the specific quality-of-life score SNOT-22, is established, and improvement in olfactory function is expected in 50% of patients. The rate of surgical revision is at least 10-15% at 4 years, but the disease can be controlled for several years, with the interval between primary surgery and symptomatic recurrence exceeding 10 years in some cases. The criteria for surgery are not clearly defined in the literature. However, several authors consider failure of ≥ 8 weeks' well-conducted local medical treatment and use of more than 2 courses of systemic corticosteroids as a reliable indication. No studies or meta-analyses are currently available to determine the superiority of one surgical technique over another.

Consensus on the management of united airways disease with type 2 inflammation: a multidisciplinary Delphi study

BACKGROUND

Scientific evidence on patients with multimorbid type 2 asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) from a united airways disease (UAD) perspective remains scarce, despite the frequent coexistence of these entities. We aimed to generate expert consensus-based recommendations for the management of UAD patients.

METHODS

Using a two-round Delphi method, Spanish expert allergists, pulmonologists and otolaryngologists expressed their agreement on 32 statements (52 items) on a 9-point Likert scale, classified as appropriate (median 7-9), uncertain (4-6) or inappropriate (1-3). Consensus was considered when at least two-thirds of the panel scored within the range containing the median.

RESULTS

A panel of 30 experts reached consensus on the appropriateness of 43 out of the 52 (82.7%) items. The usefulness of certain biomarkers (tissue and peripheral blood eosinophil count, serum total IgE, and fraction of exhaled nitric oxide [FeNO]) in the identification and follow-up of type 2 inflammation, and assessment of the response to biologics, were agreed. Some of these biomarkers were also associated with disease severity and/or recurrence after endoscopic sinus surgery (ESS). Consensus was achieved on treatment strategies related to the prescription of anti-IL-4/IL-13 or anti-IgE agents, concomitant treatment with systemic corticosteroids, and combining or switching to biologics with a different mechanism of action, considering a number of UAD clinical scenarios.

CONCLUSION

We provide expert-based recommendations to assist in clinical decision-making for the management of patients with multimorbid type 2 asthma and CRSwNP. Specific clinical trials and real-world studies focusing on the single-entity UAD are required to address controversial items.

Olfactory changes after endonasal endoscopic cerebrospinal fluid fistula repair: long-term outcomes

OBJECTIVE

This study aimed to evaluate odour measurements after endoscopic repair of cerebrospinal fluid fistulas.

METHOD

Demographic characteristics, cerebrospinal fluid leak location, surgical procedure, aetiology and smell test results were retrospectively reviewed.

RESULTS

A total of 27 patients were included. The mean age was 43.52 years. The aetiology was spontaneous in 13 patients (48.1 per cent) and traumatic in 14 patients (51.9 per cent). The skull base defect was at the cribriform plate in 15 patients (55.6 per cent), the frontal sinus posterior wall in 4 patients (14.8 per cent), the sphenoid sinus posterior wall in 4 patients (14.8 per cent), around the anterior ethmoid artery in 2 patients (7.4 per cent), at the ethmoid roof in 1 patient (3.7 per cent) and at the sphenoid sinus posterolateral wall in 1 patient (3.7 per cent). After the comparison of pre-operative and post-operative values in identification, discrimination and threshold categories, a statistically significant difference was seen only in the threshold category (p = 0.014).

CONCLUSION

The results demonstrated that endoscopic repair of cerebrospinal fluid leak is safe in terms of olfactory functions.

Olfaction Now and in the Future in CRSwNP

BACKGROUND

Chronic rhinosinusitis (CRS) is the leading cause of olfactory dysfunction in the general population. Olfactory dysfunction is more common in patients with CRS with nasal polyposis (CRSwNP) compared to those without polyps.

PURPOSE

The present review aims to summarize the current literature on the mechanism behind olfactory dysfunction in CRSwNP and the impact of therapy on olfactory outcomes in this patient population.

METHODS

A comprehensive review of the available literature on olfaction in CRSwNP was performed. We evaluated the most recent evidence from studies on the mechanisms behind smell loss in CRSwNP and the impact of medical and surgical therapy for CRS on olfactory outcomes.

RESULTS

The mechanism behind olfactory dysfunction in CRSwNP is not completely understood, but evidence from clinical research and animal models suggests both an obstructive component causing conductive olfactory loss and an inflammatory response in the olfactory cleft leading to sensorineural olfactory loss. Oral steroids and endoscopic sinus surgery have both shown efficacy in improving olfactory outcomes in CRSwNP in the short term; however, the long-term response of these treatments remains uncertain. Newer targeted biologic therapies, such as dupilumab, have also shown remarkable and durable improvement in smell loss for CRSwNP patients.

CONCLUSION

Olfactory dysfunction is highly prevalent in the CRSwNP population. Although significant advances have been made in our understanding of olfactory dysfunction in the setting of CRS, additional studies are needed to elucidate cellular and molecular changes mediated by type 2-mediated inflammation in the olfactory epithelium with potential downstream effects on the central olfactory system. Further identification of these underlying basic mechanisms will be vital for developing future therapies targeted to improve olfactory dysfunction in patients with CRSwNP.

Effects of nasal inflammation on the olfactory bulb

Sinonasal diseases, such as rhinosinusitis, affect up to 12% of individuals each year which constitutes these diseases as some of the most common medical conditions in the world. Exposure to environmental pathogens and toxicants via the nasal cavity can result in a severe inflammatory state commonly observed in these conditions. It is well understood that the epithelial and neuronal cells lining the olfactory mucosa, including olfactory sensory neurons (OSNs), are significantly damaged in these diseases. Prolonged inflammation of the nasal cavity may also lead to hyposmia or anosmia. Although various environmental agents induce inflammation in different ways via distinct cellular and molecular interactions, nasal inflammation has similar consequences on the structure and homeostatic function of the olfactory bulb (OB) which is the first relay center for olfactory information in the brain. Atrophy of the OB occurs via thinning of the superficial OB layers including the olfactory nerve layer, glomerular layer, and superficial external plexiform layer. Intrabulbar circuits of the OB which include connectivity between OB projection neurons, OSNs, and interneurons become significantly dysregulated in which synaptic pruning and dendritic retraction take place. Furthermore, glial cells and other immune cells become hyperactivated and induce a state of inflammation in the OB which results in upregulated cytokine production. Moreover, many of these features of nasal inflammation are present in the case of SARS-CoV-2 infection. This review summarizes the impact of nasal inflammation on the morphological and physiological features of the rodent OB.

Reboot surgery for chronic rhinosinusitis with nasal polyposis: recurrence and smell kinetics

OBJECTIVE

To evaluate the time for recovery of the sense of smell in patients with CRSwNP who underwent Reboot surgery compared to patients undergoing ESS in a long-term follow-up study.

METHODS

Data were collected retrospectively from 168 patients with severe uncontrolled CRSwNP, who underwent revision surgery, either as Extended Endoscopic Sinus Surgery (Reboot, 140 patients) or as regular Endoscopic Sinus Surgery (ESS, 28 patients) between January 1, 2014, and December 31, 2015, aiming to compare the outcome of surgeries after 2 years of follow-up. Sense of smell was scored as judged by the patient using scores 0 to 3 reflecting a percentage estimate of remaining smell.

RESULTS

Smell improved similarly in the Reboot and ESS groups over the first 9 months, which was maintained over 24 months in the Reboot, but not the ESS group (p = 0.007 after 18 months, p = 0.001 after 24 months). Furthermore, polyp recurrence rates were significantly lower in the Reboot group.

CONCLUSION

Reboot surgery significantly improved olfactory function and significantly reduced nasal polyp recurrence rates over 2 years post-operatively. Therefore, Reboot should be considered for patients with uncontrolled severe CRSwNP, specifically when ESS failed, to offer long-term smell and a polyp-free status.

LEVEL OF EVIDENCE

3b.

Real-world-effectiveness of biological treatment for severe chronic rhinosinusitis with nasal polyps

Background: During the last two years, three different monoclonal antibodies have been approved in many countries for the treatment of patients suffering from severe chronic rhinosinusitis with nasal polyps (CRSwNP). Their efficacy has been demonstrated through large double-blind placebo-controlled clinical studies. Until now, only very limited reports on real-world data regarding this therapy have been published. Methods: This per protocol analysis included patients with an indication for biological treatment because of uncontrolled CRSwNP, despite long-term nasal steroid treatment, systemic steroid use and/ or endonasal sinus surgery. Baseline data on demographics, medical history and comorbidities, polyp score, quality of life and sense of smell (using Sniffin´ Sticks) were assessed and a treatment with either dupilumab or omalizumab was started. The patients were followed up after three and six months. The changes in polyp score, quality-of-life measures and olfaction were noted. Results: 70 consecutive patients were evaluated during the study. Of the patients, 49 were treated with dupilumab and 21 with omalizumab. The polyp score decreased significantly after three and six months, and the quality-of-life parameters and olfaction increased. More than 90% of patients showed a moderate to excellent response to the therapy and there was no difference in the overall response between the two treatments. Olfaction improved in two thirds of the patients, but one third was still anosmic after six months treatment. Conclusions: This real-world study shows the effectiveness of the monoclonal antibodies dupilumab and omalizumab in the treatment of severe CRSwNP. Nasal polyp scores and quality-of-life parameters as well as measured olfactory function were improved after just three months. The response after guideline-based criteria was insufficient only in 5 patients of this cohort.

Olfactory Change Pattern After Endoscopic Sinus Surgery in Chronic Rhinosinusitis Patients

Background Chronic rhinosinusitis (CRS) is a chronic inflammation of the sinonasal mucosa that is clinically associated with sinus pressure, nasal congestion, rhinorrhea, and a decreased sense of smell that lasts more than 12 weeks. Endoscopic sinus surgery (ESS) for medically refractory CRS is mainly undergone to improve sinus function and access to topical medicinal treatments. However, olfactory changes after ESS can be unpredictable. Aim The current study aimed to assess olfactory change patterns after endoscopic sinus surgery in patients with chronic rhinosinusitis. Methods A record-based retrospective study was conducted in Aseer Central Hospital (ACH) ear, nose, and throat outpatient (ENT OPD) department and Khamis Mushayt General Hospital from August 15, 2021, to December 15, 2021. Data were collected using pre-structured data extraction sheet to avoid errors. Data extracted and collected included patients' biodemographic data, CRS-associated symptoms, and endoscopic surgery-related data, including duration since surgery, presurgical medications, and duration of surgery. Also, postsurgical complications were extracted, especially olfactory complications. Results A total of 168 patients with chronic rhinosinusitis (CRS) and who had undergone endoscopic sinus surgery in the Aseer region were included. Patient ages ranged from 10 to 61 years, with a mean age of 39.8 ± 12.4 years old. Regarding the associated symptoms and complaints of the study patients, 110 (65.5%) complained of sinusitis, and 86 (51.2%) had allergic RS. The postsurgical complications of patients with CRS who had undergone endoscopic sinus surgery were olfactory dysfunction (OD) in 32 (19%), no complications in 115 (68.55%), and other nonspecific complications, such as headache, drowsiness, nose dryness, and bleeding, in 21 (12.55%). Also, 71 (42.3%) reported that they hardly perceive the fragrance in perfumeries. Conclusion In conclusion, olfactory impairment is a frequent clinical presentation in patients with CRS. In this study, olfactory dysfunction was improved, except among nearly one out of each five patients after ESS. Olfactory dysfunction was more among patients who had undergone recent surgery and those with chronic rhinosinusitis with nasal polyps (CRSwNP). Also, among patients who reported no complications, olfactory function did not return to normal in most patients as they hardly perceive fragrance.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Nasal polyp load determines the recovery of olfaction after surgery for chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is typically accompanied by impairment of olfaction. Despite of this, until today the efficacy of endonasal sinus surgery (ESS) in terms of olfactory function is still unclear. So far it is known that patients with nasal polyps are most likely to experience post-operative recovery. Within the present study we investigated the sense of smell and other parameters of impairment in CRS before and after ESS in relation to the degree of nasal polyposis, determined with the nasal endoscopic Lildholdt-score.

METHODS

Patients with different degrees of severity of nasal polyposis were included. Olfactory function was assessed for odor thresholds [T], odor discrimination [D] and odor identification [I] and the changes of these parameters were investigated postoperatively.

RESULTS

For 72 patients baseline measures were available and in 47 patients, postoperative changes were described. There was a correlation between olfactory scores and nasal anatomy/polyposis scores (Lildholdt scores, Lund-Mackay CT score), rated nasal health, and nasal quality of life (sinonasal outcome test). Three months after surgery the average TDI-Score improved by 3.1 points with 30% of patients showing significant clinical improvement. Patients with severe polyposis (Lildholdt score of 5 or 6) benefited most in terms of olfaction. Other significant prognostic indicators of a postoperative increase of olfactory scores included younger age, low pre-operative TDI-scores and high CT-scores.

CONCLUSIONS

This study shows that not only the presence of polyps in CRS, but also the degree of nasal polyposis - measured by a grading system - predicts the results in olfactory test results. Additionally, the degree of recovery of olfaction after ESS seems to be most relevant in patients with high polyp scores.

Protective Effect of Insulin in Mouse Nasal Mucus Against Olfactory Epithelium Injury

Insulin is present in nasal mucus and plays an important role in the survival and activity of individual olfactory sensory neurons (OSNs) via insulin receptor-mediated signaling. However, it is unclear whether insulin acts prophylactically against olfactotoxic drug-induced olfactory epithelium (OE) injury, and whether the degree of damage is affected by the concentration of insulin in the nasal mucus. The apoptosis-inducing drug methimazole was administered to the nasal mucus of diabetic and normal mice along with different concentrations of insulin. Immunohistochemical analysis was used to assess the relationship between damage to the OE and the mucus insulin concentration and the protective effect of insulin administration against eosinophilic cationic protein (ECP)-induced OE injury. Diabetic mice had lower concentrations of insulin in their nasal mucus than normal mice (diabetic vs. normal mice, p < 0.001). Methimazole administration reduced the number of OSNs in normal mice and had a more marked effect in diabetic mice. However, unilateral insulin administration prevented the methimazole-induced reduction in the number of OSNs on the ipsilateral side but not on the contralateral side (OSNs; Insulin vs. contralateral side, p < 0.001). Furthermore, intranasal ECP administration damaged the OE by inducing apoptosis (OSNs; ECP vs. contralateral side, p < 0.001), but this damage was largely prevented by insulin administration (OSNs; Insulin + ECP vs. contralateral side, p = 0.36), which maintained the number of mature OSNs. The severity of methimazole-induced damage to the OE is related to the insulin concentration in the nasal mucus (Correlation between the insulin concentration in nasal mucus and the numbers of OSNs, R² = 0.91, p < 0.001), which may imply that nasal insulin protects OSNs and that insulin administration might lead to the development of new therapeutic agents for ECP-induced OE injury.

Long Term Olfactory Outcomes Following Frontal Sinus Surgery in Chronic Rhinosinusitis

OBJECTIVES/HYPOTHESIS

No studies have evaluated the impact of the types of frontal sinus surgery (FSS) on objective olfaction scores. This study evaluated olfactory function and quality of life (QOL) in chronic rhinosinusitis (CRS) patients before and after total ethmoidectomy with frontal sinusotomy (FS).

STUDY DESIGN

Prospective cohort study.

METHODS

A prospective study of adult CRS patients undergoing FSS (Draf 2 or Draf 3 procedures) was conducted at a tertiary care center. Primary outcomes included brief smell identification test (BSIT) and sinonasal outcome test-22 (SNOT-22), which were assessed during preoperative evaluation, 6 to 9 weeks postoperatively, and 12 to 24 weeks postoperatively. Normosmia was defined as BSIT ≥9. Statistical significance was determined using the Wilcoxon signed-rank test with α = .05.

RESULTS

Thirty-eight patients followed up 12 to 24 weeks after FSS. The differences between baseline and long-term outcomes for BSIT (6.11 vs. 8.24, P = .00034) and SNOT-22 (55.49 vs. 24.32, P < .00001) scores were found to be statistically significant. Although both subgroups had clinically significant olfactory improvements, only the Draf 2 cohort experienced a statistically significant improvement in olfaction at long-term follow-up. There was no statistically significant change in data from 6 to 9 weeks to 12 to 24 weeks postoperatively.

CONCLUSIONS

Patients undergoing total ethmoidectomy with FS demonstrated statistically significant increases in olfaction and QOL at long-term postoperative follow-up. This study demonstrated that FS does not negatively impact the olfactory improvement seen in sinus surgery. The lack of statistically significant changes in these olfactory metrics from short to long-term follow-up suggests that there is no additional negative effect of FSS in the long term.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Reversibility of mucociliary clearance and olfaction impairment following endoscopic sinus surgery: a prospective observational study

OBJECTIVE

Chronic rhinosinusitis is associated with altered mucociliary clearance and olfaction. The study aimed to analyse the reversibility of impairment and endoscopic factors predicting changes in mucociliary clearance and olfactory parameters.

METHODS

This prospective study included patients undergoing functional endoscopic sinus surgery for medically refractory chronic rhinosinusitis. Pre- and post-operative measurements of mucociliary clearance, olfactory thresholds, and identification scores were recorded.

RESULTS

Of the 96 patients, 65.6 per cent had polyposis and 80.2 per cent underwent primary surgery. Improvements in mucociliary clearance and olfaction scores were seen in all patients, with greater reversibility of impairment in patients with polyposis and in those who underwent revision surgery. The presence of polyps correlated significantly with changes in mucociliary clearance and olfaction.

CONCLUSION

The study highlights improvements in mucociliary clearance, olfactory thresholds and identification scores after functional endoscopic sinus surgery in chronic rhinosinusitis with or without nasal polyposis, as well as for primary and revision surgeries. Adequate post-operative care and prevention of polyps recurrence help to improve mucociliary clearance and olfaction scores.

Endotyping chronic rhinosinusitis based on olfactory cleft mucus biomarkers

BACKGROUND

Although chronic rhinosinusitis (CRS) is considered the most treatable form of olfactory dysfunction, there has been relatively little clinical attention focused on assessing endotypes as they pertain to olfactory loss.

OBJECTIVES

The goal of this study was to explore inflammatory endotypes in CRS using an unsupervised cluster analysis of olfactory cleft (OC) biomarkers in a phenotype-free approach.

METHODS

Patients with CRS were prospectively recruited and psychophysical olfactory testing, Questionnaire of Olfactory Dysfunction (QOD-NS), and bilateral OC endoscopy were obtained. Mucus was collected from the OC and evaluated for 26 biomarkers using principal component analysis. Cluster analysis was performed using only OC biomarkers and differences in olfactory measures were compared across clusters.

RESULTS

A total of 198 subjects (128 with CRS and 70 controls) were evaluated. Evaluation of OC biomarkers indicated 6 principal components, explaining 69.50% of the variance, with type 2, mixed type 1/T_h17-cell, growth factor, and neutrophil chemoattractant inflammatory signatures. A total of 10 clusters were identified that differed significantly in frequency of controls, and subjects with CRS with nasal polyps, and subjects with CRS without nasal polyps across the clusters (likelihood ratio test, χ₁₈²=178.64; P < .001). Olfactory measures differed significantly across clusters, including olfactory testing, QOD-NS, and OC endoscopy (P < .001 for all).

CONCLUSIONS

Clustering based solely on OC biomarkers can organize patients into clinically meaningful endotypes that discriminate between subjects with CRS and controls. Validation studies are necessary to confirm these findings and further refine olfactory endotypes.

Smell and Taste Impairment in a Nationwide Sample of US Adults With Chronic Rhinosinusitis Symptoms

Objective

To estimate the prevalence of objectively confirmed olfactory and gustatory dysfunction in US adults reporting chronic rhinosinusitis (CRS) symptoms in a nationally representative database.

Study Design

Cross-sectional epidemiologic analysis.

Setting

Data were analyzed from the smell and taste component of the 2013-2014 NHANES data set (National Health and Nutrition Examination Survey).

Methods

Individuals reporting the presence of ≥2 cardinal CRS symptoms (nasal blockage, sinus pain, discolored mucus, and dysosmia) were identified as patients with a potential diagnosis of CRS. Associations were examined between the presence of CRS symptoms and both self-reported and objectively measured smell and taste.

Results

One-third (33%) of adults who have ≥2 CRS symptoms report subjective olfactory impairment, though only 18% of these adults have quantifiable olfactory dysfunction on objective testing. Of these adults, 27% report subjective taste impairment, but just 17% have quantifiable gustatory dysfunction on objective testing. The presence of ≥2 CRS symptoms was not significantly associated with objective olfactory or gustatory dysfunction, although the individual symptoms of subjective dysosmia and discolored mucus were associated with objectively confirmed olfactory dysfunction.

Conclusion

The prevalence of objective olfactory and gustatory dysfunction was higher among adults reporting the presence of ≥2 CRS symptoms, but the differences were not statistically significant. Specific sinonasal symptoms, including discolored mucus and subjective smell dysfunction, were significantly associated with objective smell impairment.

Essential Oil Olfactory Test: Comparison of Affordable Rapid Olfaction Measurement Array (AROMA) to Sniffin' Sticks 12

Objectives

To further demonstrate the validity of Affordable Rapid Olfaction Measurement Array (AROMA), an essential oil−based smell test, and compare it to the Sniffin’ Sticks 12 Test (SST12).

Study Design

Prospective cross-sectional study.

Setting

Academic medical center.

Methods

Fifty healthy individuals without sinonasal disease were recruited to the study. AROMA has been previously validated against the University of Pennsylvania Smell Identification Test. The current study tests 2 additional higher concentrations to increase the ability to detect olfactory reserve. Healthy participants completed AROMA, SST12, Sino-Nasal Outcome Test (SNOT-22), and Questionnaire of Olfactory Disorders (QoD). Spearman correlations were used to evaluate AROMA, SST, SNOT-22, and QoD.

Results

AROMA demonstrated strong test-retest reliability (r = 0.757, P < .01). AROMA showed a moderate correlation to SST12 (ρ = 0.412, P < .01). Age and SNOT-22 were significantly correlated (P < .05) with AROMA (ρ = −0.547, −0.331, respectively), and age was weakly correlated with SST (ρ = −0.377, P < .01). Median percent correct scores were as follows: SST12 identification, 92%; AROMA detection, 90%; and AROMA identification, 81%. Median correct odor identification of AROMA concentrations at 1×, 2×, 4×, and 8× were 64%, 75%, 92%, and 92%, respectively.

Conclusion

AROMA has a moderate correlation with SST12. AROMA is more strongly correlated than SST12 to age and SNOT-22. AROMA’s stronger correlation with subjective olfactory status, low cost, and adaptability may help remove barriers to routine olfactory testing in the clinic.

Olfactory Function After Surgical Treatment of CRS: A Comparison of CRS Patients to Healthy Controls

BACKGROUND

Many patients with chronic rhinosinusitis (CRS) have persistent olfactory dysfunction (OD) following endoscopic sinus surgery (ESS). Few studies compare outcomes to control subjects so it is unknown if residual OD is due to persistent CRS.

OBJECTIVE

Compare postoperative measures of OD in case patients with CRS to healthy controls without sinonasal disease.

METHODS

Prospective, observational, multicenter cohort study between October, 2016 and May, 2019. Case participants were selected from referred adult patients diagnosed with CRS, with or without nasal polyposis (NP), electing ESS as subsequent treatment modality. Controls voluntarily enrolled from a community-based sample without a history of CRS. Primary outcomes included measures of preoperative and postoperative OD using "Sniffin' Stick" pens which summarize odorant threshold (T), discrimination (D), and identification (I) scores. Secondary outcomes included the Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS) survey and olfactory cleft endoscopy scores (OCES).

RESULTS

Outcomes were compared between 113 cases and 164 controls of similar average age and gender. Cases reported significantly worse baseline Sniffin' Sticks TDI total scores (-6.8[SE ± 1.0]; 95% CI: -4.9 to -8.7), QOD-NS (8.9[SE ± 1.1]; 95% CI: 6.8-10.9), and OCES (3.5[SE ± 0.4]; 95% CI: 2.9-4.2) on average. Cases reported significant postoperative improvement in TDI total score (3.7[SD ± 8.2]; 95% CI: 2.2-5.2), QOD-NS (-5.9[SD ± 8.7]; 95% CI: -7.6 to -4.3), and OCES (-1.7[SD ± 3.8]; 95% CI: -2.7 to -0.8) on average, while 63% of anosmics reported improved postoperative olfaction. Multivariate regression identified that NP (OR = 0.4; 95% CI: 0.2-1.0) and previous ESS (OR = 0.3; 95% CI: 0.1-0.8) decreased the odds of postoperative improvement equal to mean TDI scores of controls, while septoplasty increased those odds (OR = 4.5; 95% CI: 1.5-13.7).

CONCLUSION

ESS improved olfactory metrics and restored olfactory function in approximately 50% of patients with CRS to that of healthy controls. Concurrent septoplasty increased the likelihood of achieving normal olfaction, while NP and previous ESS decreased those odds.

Type 1/type 2 inflammatory cytokines correlate with olfactory function in patients with chronic rhinosinusitis

BACKGROUND

Olfactory dysfunction secondary to chronic rhinosinusitis (CRS) has been highly associated with impaired quality of life. Asian CRS patients showed a distinct inflammatory profile, with less type 2 endotype compared with European and North American. This study aimed to explore the pattern of the inflammatory cytokines in CRS patients from China and their association with olfactory function.

METHODS

Institutional review board-approved prospective study in which the olfactory function of 71 CRS patients was assessed with Sniffin' Sticks before the nasal endoscopic surgery. A set of cytokines and inflammatory mediators including type 1 and type 2 inflammatory cytokines were measured in nasal mucus by using a multiplex flow cytometric bead assay (CBA). Baseline characteristics in CRS patients were collected and the Spearman r statistic was performed to assess the association of olfactory function with cytokines and inflammatory mediators.

RESULTS

A total of 71 nasal mucus samples of CRS patients, including 25 chronic rhinosinusitis without nasal polyposis (CRSsNP) patients and 46 chronic rhinosinusitis with nasal polyposis (CRSwNP) patients, were evaluated in this study. The nasal mucus levels of type 1 inflammatory cytokine IFN-γ (interferon-γ), type 2 inflammatory cytokines including IL-4, IL-5 and GM-CSF (granulocyte-macrophage colony-stimulating factor) and anti-inflammatory cytokine IL-10 were significantly and inversely correlated with olfactory function in total patients with CRS (r = -0.308, p = 0.009; r = -0.250, p = 0.036; r = -0.399, p = 0.001; r = -0.269, p = 0.023; r = -0.273, p = 0.021, respectively). In CRSsNP, the olfactory function was inversely correlated with levels of type 1 inflammatory cytokine TNF-α (tumor necrosis factor-α) (r = -0.637, p = 0.001) and IL-10 (r = -0.468, p = 0.018). Nevertheless, the olfactory function in CRSwNP was inversely correlated with type 2 inflammatory cytokines including IL-4 (r = -0.303, p = 0.041) and IL-5 (r = -0.383, p = 0.009).

CONCLUSION

Both type 1 and type 2 inflammatory cytokines may contribute to the pathogenesis of CRS-associated olfactory dysfunction in the Chinese population.

Treatable traits in chronic rhinosinusitis with nasal polyps

PURPOSE OF REVIEW

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory sinonasal disease that deserves a multidisciplinary precision medicine approach. In a precision medicine model, a more pragmatic approach taking in consideration disease features that are potentially treatable should be considered.

RECENT FINDINGS

Several treatable traits in CRSwNP can be identified: from disease-related ones, to extra-ENT features, to behavioral and environmental factors. This review article summarizes primarily the recent findings of CRSwNP-related treatable traits and how they can be modified by given treatments.

SUMMARY

The advent of biological agents acting directly to the endotype underlying CRSwNP pushes the scientific community to integrate clinical, surgical and immunological evaluations for each single patient; this naturally leads to the identification of specific treatable traits that can serve as possible outcomes for any single biological.

Olfaction in Juvenile Nasopharyngeal Angiofibroma: The first study

BACKGROUND

To study the pattern of olfactory dysfunction/recovery in juvenile nasopharyngeal angiofibroma (JNA).

METHODS

Olfactory assessment was undertaken in 30 patients (category1) both pre- & post-operatively and in another 18 (category 2) only postoperative. All patients underwent transpalatal excision and variables of interest included age, radiological stage/parameters & tumor size.

RESULTS

Objective olfactory dysfunction was seen in 60% while involvement of olfactory strip was suggested in 50%. Despite some marginal trends only noted between size/age with change of olfaction, Pearson's correlation test did not reveal any significance amongst multiple variables. However a better recovery of olfaction following surgery was evident in Category-2 where Chi-Square test (p < 0.05) significantly revealed this to be a function of postoperative duration. This regenerative course in JNA suggests an optimum period of 4 years for full recovery after surgery.

CONCLUSION

In this first study of olfaction in JNA many new trends have been appreciated. In general, deteriorations of olfaction were seen due to 'vascular-concussion' effect in early postoperative phase where post-surgical clearance of airway showed minimal effect in terms of improvement. The hypervascularity of olfactory epithelium with possible hormonal effects may be responsible for the unique pattern of olfactory function and recovery in JNA.

Superior turbinate eosinophilia predicts olfactory decline in patients with chronic rhinosinusitis

BACKGROUND

Predicting postoperative olfactory decline in patients with chronic rhinosinusitis (CRS) remains a considerable challenge.

OBJECTIVE

To evaluate patterns of postoperative olfactory function in patients with CRS and explore potential predictors of postoperative olfactory decline.

METHODS

A total of 76 patients with CRS electing endoscopic sinus surgery (ESS) were enrolled in this prospective study. Olfaction was assessed with Sniffin' Sticks preoperatively and 3 months postoperatively. Preoperative peripheral venous blood and superior turbinate at surgery were collected for eosinophil quantification. Olfactory cleft was evaluated by computed tomography and endoscopy. Postoperative olfactory decline was defined by a decrease in threshold-discrimination-identification (TDI) score more than 0 point. Multivariable logistic regression analysis was conducted to identify potential predictors associated with postoperative olfactory decline in TDI score.

RESULTS

A total of 30.26% of patients with CRS (23/76) presented with olfactory decline 3 months post-ESS. Patients with CRS with olfactory decline showed significantly higher preoperative tissue eosinophils (P < .001), blood eosinophil count (P = .002), blood eosinophil percentage (P = .009), and preoperative TDI scores (P = .017) than patients with CRS without olfactory decline. After adjusting for patient demographics and comorbidities, the preoperative tissue eosinophilia was significantly associated with patients with CRS with postoperative olfactory decline (odds ratio = 1.103; P = .038). An absolute count of 23.5 eosinophils per high-power field in superior turbinate was the best predictor of olfactory decline with the highest area under the receiver operating characteristic curve of 0.901.

CONCLUSION

Superior turbinate eosinophilia is highly associated with olfactory decline in patients with CRS 3 months after ESS.

Olfactory Dysfunction and Chronic Rhinosinusitis

Olfactory dysfunction (OD) is one of the cardinal symptoms of chronic rhinosinusitis (CRS), and its prevalence ranges from 60% to 80% in patients with CRS. It is much more common in CRS with nasal polyposis patients compared to CRS without nasal polyposis. Decreased olfactory function is associated with significant decreases in patient-reported quality of life (QOL), and notably, depression and the enjoyment of food. Objective measures can help detail the degree of OD, whereas subjective measures can help to determine in the impact on patient. There is variable treatment response to OD with both medical and surgical therapies.

The Impact of Septoplasty Operation on Odor Threshold Score and Symptom Severity According to the Nasal Septum Deviation Classifications

OBJECTIVE

The authors aimed to determine the changes in the odor threshold and sinonasal outcome test-22 scores of the patients after septoplasty surgery in terms of nasal septum deviation classifications.

METHODS

Forty-nine patients with nasal septum deviation, aged between 17 and 65, were included in our study. The sinonasal outcome test-22 scores questionnaire and the N-Butanol Threshold test were administered to the patients, 2 days before and 2 months after the septoplasty.

RESULTS

The authors' study had 4 major findings: Odor threshold scores improved after septoplasty operation both for the narrower and the wider side of the nasal airway passage. The Vidigal classification for nasal septum deviation was best for predicting the changes for odor threshold scores after septoplasty operation. The nasal septum deviation in which the nasal septum was pushing the inferior turbinate to lateral nasal wall caused the most smell dysfunction according to the Vidigal classification. Unilateral vertical crest affecting the nasal valv area or the posterior part of the septum had the most negative effect on olfactory functions according to the Mladina classification.

CONCLUSION

Septoplasty operation leads to improvement in odor threshold scores, and the Vidigal nasal septum deviation classification was best in predicting postoperative odor threshold changes.