Abstract
Introduction
Olfactory loss is a cardinal symptom of chronic rhinosinusitis (CRS) and affects 40–80% of patients. However, common sinus-specific quality-of-life (QOL) instruments include only single questions related to olfaction. Few studies have explored olfactory outcomes after surgery utilizing validated, olfaction-specific QOL questionnaires.
Methods
Patients with CRS were enrolled from 3 centers across North America into a prospective cohort study. Patients completed the short modified version of the Questionnaire of Olfactory Disorders (QOD-NS) and the 40-item Smell Identification Test (SIT-40) before and at least 6 months after endoscopic sinus surgery (ESS). Multivariate linear regression was used to determine whether specific demographic, comorbidity, or disease severity measures were independently associated with QOD scores at baseline or predicted change after surgery.
Results
A total of 121 patients, equally split between genders, were enrolled with an average age of 47.9 years (range: 18–80). Baseline total QOD-NS scores were significantly associated with SIT-40 scores, with a moderate strength of correlation (Rs=0.400; p<0.001). The average QOD-NS score improved after ESS (35.7±13.0 vs. 39.7±12.2; p=0.006). Allergy, polyps, and steroid dependent conditions were found to be independently associated with worse preoprerative QOD-NS scores, while septal deviation was associated with better QOD-NS scores. Baseline computed tomography (CT) scores were the only variable which significantly predicted change in QOD-NS after surgery.
Conclusion
Olfaction-specific QOL is worse in patients with polyps and comorbid allergy. Significant improvements in olfaction-specific QOL are seen after ESS, with the greatest gains seen in those with worse CT scores at baseline.
Keywords: sinusitis, olfaction, quality of life, clinical outcomes, patient reported outcome measures
INTRODUCTION
Olfactory loss is one of four cardinal symptoms of chronic rhinosinusitis (CRS) and can affect up to 80% of patients1. In CRS a number of potential factors have been proposed to relate to objective olfactory function, including nasal polyps, gender and age. When examining objective olfactory outcomes using validated instruments, such as Smell Identification Test 40 (SIT40) or Sniffin’ Sticks, endoscopic sinus surgery (ESS) improves objective olfaction in 23 – 68% of patients with baseline olfactory dysfunction2–4. Few studies, however, have examined patient-reported, olfaction-specific quality of life (QOL) in CRS or outcomes after ESS.
Numerous studies have demonstrated that ESS improves subjective CRS outcomes, including overall sinus-specific QOL by approximately 50%5. The cardinal symptoms of nasal discharge, facial pain/pressure and blockage/congestion of the nose also improved by 50% or greater2, but subjective olfactory loss had the least improvement of the cardinal symptoms, improving by only 37%2. Additionally, common sinus-specific QOL instruments, such as the Sinonasal Outcome Test-22 (SNOT-22), may be limited in their ability to measure true differences in olfactory loss, as only one question relates to olfaction. Thus the true impact of olfactory loss upon QOL and subjective olfactory outcomes after surgery utilizing validated, olfaction-specific QOL questionnaires remains to be determined.
The goals of this study were: 1) to examine baseline olfactory-specific QOL, as measured by Questionnaire of Olfactory Disorders (QOD-NS)6, in a cohort of patients with CRS who had failed medical therapy and were preparing to undergo ESS; 2) to examine changes in QOD-NS after ESS; and 3) to determine clinical factors that correlate with both baseline and post ESS changes in QOD-NS.
METHODS
Study Population
Adult (≥18 years) patients with CRS were recruited from rhinology clinics at Medical University of South Carolina (MUSC, Charleston, SC), Oregon Health and Sciences University (OHSU, Portland, OR), and University of Utah (Salt Lake City, UT), as part of an on-going prospective cohort study. This study was approved in advance by the Institutional Review Boards at each institution and all subjects provided written, informed consent in English. Each patient fulfilled diagnostic criteria for CRS according to Clinical Practice Guideline of the American Academy of Otolaryngology-Head and Neck Surgery. Each study participant self-selected endoscopic sinus surgery (ESS) for treatment of recalcitrant symptoms associated with CRS. Using standardized questionnaires, preoperative characteristics related to demographics and medical comorbidities was collected for each patient, including the presence of septal deviation, nasal polyposis, asthma, aspirin exacerbated respiratory disease (AERD), allergic rhinitis, depression, diabetes mellitus, tobacco use, oral steroid dependency, and a history of previous sinus surgery. High resolution computed tomography (CT) scans were obtained on each patient during the course of routine clinical care and prior to sinus surgery in all instances. CT scans were evaluated by the enrolling physician and the degree of sinus opacification was scored using the Lund-Mackay staging system, with the reviewer blinded to other study data. Nasal endoscopy was performed on each patient and those with visible polyps were classified as CRS with nasal polyposis (CRSwNP) and those without visible polyps as CRS without polyps (CRSsNP). Nasal endoscopy exams were scored semi-quantitatively using the Lund-Kennedy staging system.
Olfactory outcome metrics
Objective olfactory function was quantified using the 40-item Smell Identification Test (SIT-40, Sensonics Inc., Haddon Heights, NJ). The SIT-40 is a validated, forced choice, “scratch and sniff” test utilizing microencapsulated odorant strips (score: 0–40). Our primary outcome of interest was olfactory-specific QOL that was assessed using the previously validated, short modified version of the Questionnaire of Olfactory Disorders (QOD-NS)6. This instrument consists of 17 negative statements that are graded on a scale from 0 to 3 for a total score ranging from 0 to 51 with higher scores reflecting better QOL. Each patient completed two surveys of sinus-specific QOL: the Rhinosinusitis Disability Index (RSDI) and the Sinonasal Outcome Test-22 (SNOT-22). Olfactory specific questions from these questionnaires were assessed independently, including question 21 of the SNOT-22, “how bad is your sense of smell/taste“ and question 7 from the physical subdomain of the RSDI “food does not taste good because of my change in smell“. All olfactory metrics were collected preoperatively and again after ESS (minimum 6 months).
Statistical analysis
Statistical analyses were performed using a commercially available software application (SPSS v.22, IBM Corporation, Armonk, NY). Descriptive statistics are reported using means [standard deviation], frequency, and range where appropriate and graphical analysis evaluated linear trends between continuous study variables. Mann Whitney U tests were used to compare mean QOD-NS among various demographic, co-morbid and disease classifications. Omnibus comparisons of mean QOL measures between olfactory subgroups (anosmia, hyposmia, and normosmia) were conducted using analysis of variance (ANOVA) with subsequent adjustments for multiple comparisons. Spearman’s rank correlation coefficients (Rs) were used to evaluate non-parametric correlations between study variables. Multivariate linear regression was used to determine whether specific demographic, comorbidity, or disease severity measures were independently associated with QOD-NS scores at baseline or predicted change after surgery.
RESULTS
Study Cohort
The overall cohort included 121 patients with CRS, equally split between genders, with 51 (42%) having CRSwNP. Other demographic factors, medical comorbidities, and measures of disease severity are summarized in Table 1. Overall baseline SIT40 scores were 26.4 [10.3], with 28 patients categorized with anosmia (23%) and 59 with hyposmia (49%) based on SIT score classifications. Significant differences were seen in QOD-NS scores among patients with normosmia, hyposmia, and anosmia (Table 2). After adjusting for mulitiple comparisons, each QOD-NS baseline mean score is significantly different (p<0.001) between each of the three SIT-40 categories (anosmic vs hyposmic, p<0.001; anosmic vs normosmic, p<0.001; hyposmic vs normosmic, p<0.001). The average SNOT-22 Q#21 baseline score is significantly different between anosmic and hyposmic categories (p<0.001) as well as between anosmic and normosmic categories (p<0.001), but not different between hyposmic and normosmic categories (p=0.291). Similarly, the average RSDI physical subdomain Q#7 baseline score is significantly different between anosmic and hyposmic categories (p<0.001) as well as anosmic and normosmic categories (p<0.001), but not significantly different between hyposmic and normosmic categories (p=0.578).
Table 1.
Baseline demographic, comorbidity, CRS and olfactory metrics of all patients (n=121)
| Demographics: | Mean [SD] | [RANGE] | N (%) |
|---|---|---|---|
| Age (years) | 47.9 [17.2] | [18 – 80] | |
| Males | 61 (50%) | ||
| White/caucasian | 109 (90%) | ||
| African American | 10 (8%) | ||
| Asian | 1 (1%) | ||
| Hispanic/Latino | 1 (1%) | ||
| Comorbid conditions: | |||
| Asthma | 52 (43%) | ||
| Allergy (testing confirmed) | 80 (66%) | ||
| AERD | 14 (12%) | ||
| Diabetes mellitus (Type I or II) | 10 (8%) | ||
| Depression | 23 (19%) | ||
| Obstructive sleep apnea | 15 (12%) | ||
| Ciliary dyskinesia | 3 (3%) | ||
| GERD | 37 (31%) | ||
| Current tobacco use | 8 (7%) | ||
| Disease characteristics: | |||
| Nasal polyposis | 51 (42%) | ||
| Prior sinus surgery | 69 (57%) | ||
| Septal deviation | 30 (25%) | ||
| Turbinate hypertrophy | 17 (14%) | ||
| Corticosteroid dependency | 17 (14%) | ||
| Disease severity: | |||
| SNOT-22 total score | 56.8 [20.3] | [6 – 102] | |
| RSDI total score | 51.1 [24.1] | [2 – 111] | |
| Computed tomography score | 12.9 [6.3] | [1 – 24] | |
| Endoscopy score | 5.9 [3.2] | [0 – 20] | |
| Olfactory function measures: | |||
| QOD-NS score | 35.2 [13.3] | [0 – 51] | |
| SIT-40 score | 26.4 [10.3] | [0 – 38] | |
| SNOT-22 Q#21 | 3.0 [1.8] | [0 – 5] | |
| RSDI physical subdomain Q#7 | 2.0 [1.4] | [0 – 4] |
SD, standard deviation; AERD, aspirin exacerbated respiratory disease; GERD, gastroesophageal reflux disease; SNOT-22, 22-item SinoNasal Outcome Test; RSDI, Rhinosinusitis Disability Index; QOD, Questionnaire for Olfactory Disorders; NS, negative statements; SIT-40, Smell Identification Test-40; Q, question item
Table 2.
Average baseline olfactory-specific scores classified by SIT-40
| Olfactory-specific metric mean [SD] | Anosmic (n=28) | Hyposmic (n=59) | Normosmic (n=34) | p-value |
|---|---|---|---|---|
| SIT-40 | 9.6 [4.3] | 29.0 [4.1] | 35.7 [1.2] | <0.001 |
| QOD-NS | 25.0 [10.1] | 36.7 [13.8] | 41.1 [9.9] | <0.001 |
| SNOT-22 Q#21 | 4.6 [0.8] | 2.8 [1.8] | 2.2 [1.6] | <0.001 |
| RSDI physical subdomain Q#7 | 3.3 [1.0] | 1.8 [1.3] | 1.4 [1.2] | <0.001 |
SD, standard deviation; SNOT-22, 22-item SinoNasal Outcome Test; RSDI, Rhinosinusitis Disability Index; QOD, Questionnaire for Olfactory Disorders; NS, negative statements; SIT-40, Smell Identification Test-40; Q, question item. p-values reflect omnibus ANOVA results.
Factors associated with baseline QOD-NS
The impact of various demographic, comorbidities and disease severity measures upon baseline QOD-NS was examined (Table 3). Baseline QOD-NS was worse in patients with asthma, allergy, AERD, obstructive sleep apnea, nasal polyps and steroid dependency. Baseline QOD-NS was significantly associated with all CRS specific measures: total SNOT-22, RSDI, CT and endoscopy. Baseline QOD-NS was also associated with olfactory metrics including SIT-40 scores, with a moderate strength of correlation (Rs=0.400; p<0.001) and an even stronger correlation between baseline QOD-NS and other subjective olfactory-specific questions from existing QOL instruments (Table 3).
Table 3.
Comparison of baseline QOD-NS measures across demographics, comorbidity, and disease characteristics (n=121)
| Present | Absent | ||
|---|---|---|---|
| Demographics: | Mean [SD] | Mean [SD] | p-value |
| Males | 35.9 [13.2] | 34.6 [13.5] | 0.730 |
| White/caucasian | 35.6 [13.1] | 32.2 [15.4] | 0.383 |
| Hispanic/Latino | 48.0 [---] | 35.1 [13.3] | 0.479 |
| Comorbid conditions: | |||
| Asthma | 31.9 [13.9] | 37.8 [12.4] | 0.014 |
| Allergy (testing confirmed) | 32.5 [13.1] | 40.7 [12.2] | 0.001 |
| AERD | 25.4 [14.8] | 36.5 [12.6] | 0.006 |
| Diabetes mellitus (Type I or II) | 39.0 [7.9] | 34.9 [13.7] | 0.540 |
| Depression | 34.7 [13.4] | 35.4 [13.4] | 0.856 |
| Obstructive sleep apnea | 27.8 [14.0] | 36.3 [13.0] | 0.029 |
| Ciliary dyskinesia | 40.7 [16.2] | 35.1 [13.3] | 0.381 |
| GERD | 35.7 [13.7] | 35.0 [13.2] | 0.698 |
| Current tobacco use | 28.4 [10.5] | 35.7 [13.4] | 0.098 |
| Disease characteristics: | |||
| Nasal polyposis | 28.6 [13.2] | 40.1 [11.3] | <0.001 |
| Prior sinus surgery | 34.2 [13.0] | 36.6 [13.7] | 0.276 |
| Septal deviation | 41.6 [10.4] | 33.1 [13.6] | 0.001 |
| Turbinate hypertrophy | 36.6 [14.0] | 35.0 [13.3] | 0.530 |
| Corticosteroid dependency | 25.8 [15.4] | 36.8 [12.4] | 0.004 |
| Age and CRS disease severity measures: | Rs (p-value) | ||
| Age | 0.055 (0.549) | ||
| SNOT-22 total score | −0.502 (<0.001) | ||
| RSDI total score | −0.546 (<0.001) | ||
| Computed tomography score | −0.414 (<0.001) | ||
| Endoscopy score | −0.316 (0.001) | ||
| Olfactory specific measures: | |||
| SIT-40 score | 0.400 (<0.001) | ||
| SNOT-22 Q#21 | −0.631 (<0.001) | ||
| RSDI physical subdomain Q#7 | −0.673 (<0.001) |
SD, standard deviation; AERD, aspirin exacerbated respiratory disease; GERD, gastroesophageal reflux disease; SNOT-22, 22-item SinoNasal Outcome Test; RSDI, Rhinosinusitis Disability Index; QOD, Questionnaire for Olfactory Disorders; NS, negative statements; SIT-40, Smell Identification Test-40; Q, question item
Regression analysis was performed on the multiple baseline demographic and comorbidity factors to determine independent predictors of baseline QOD-NS. Allergy, polyps and steroid dependency remained significantly associated with poorer (lower) baseline QOD-NS scores, while septal deviation was associated with better (higher) QOD-NS scores (Table 4).
Table 4.
Regression analysis of baseline factors to predict baseline QOD-NS
| Factor | Unstandardized coefficients | Standardized coefficients | t | P value | |
|---|---|---|---|---|---|
| B | Standard error | Beta | |||
| CRSwNP | −9.276 | 2.115 | −.345 | −4.386 | <0.001 |
| Allergy by testing | −5.227 | 2.267 | −.186 | −2.306 | 0.023 |
| Steroid dependence | −9.547 | 2.947 | −.250 | −3.239 | 0.002 |
| Septal deviation | 4.895 | 2.469 | .159 | 1.983 | 0.050 |
CRSwNP, Chronic rhinosinusitis with nasal polyps; QOD, Questionnaire for Olfactory Disorders; NS, negative statements
Postoperative changes in QOD-NS
A total of 61 patients of the 121 baseline cohort (51%) reached at least 6 month follow up at the end of the study. There were no differences in baseline QOD-NS and SIT-40 scores between patients that completed 6 month follow up and those that did not (p=0.656 and 0.371, respectively). The average QOD-NS score improved after ESS (35.7±13.0 vs. 39.7±12.2; p=0.006). When examining demographic, comorbid and CRS severity measures, baseline computed tomography (CT) scores were the only variable which significantly predicted change in QOD-NS after surgery (Table 5). Changes in QOD-NS scores after surgery did not correlate with SIT40 change scores, however it did correlate with other subjective olfactory questions from the SNOT-22 and RSDI.
Table 5.
Comparison of postoperative change in mean QOD-NS measures across demographics, comorbidity, and disease characteristics (n=61)
| Present | Absent | ||
|---|---|---|---|
| Demographics: | Mean [SD] | Mean [SD] | p-value |
| Males | 4.8 [10.4] | 3.1 [10.9] | 0.761 |
| White/caucasian | 4.0 [10.8] | 3.0 [8.9] | 0.645 |
| Hispanic/Latino | 3.0 [---] | 3.9 [10.7] | 0.984 |
| Comorbid conditions: | |||
| Asthma | 6.4 [10.2] | 2.1 [10.7] | 0.196 |
| Allergy (testing confirmed) | 5.2 [9.9] | 1.2 [11.6] | 0.059 |
| AERD | 7.7 [10.1] | 3.4 [10.7] | 0.379 |
| Diabetes mellitus (Type I or II) | 1.3 [9.6] | 4.2 [10.8] | 0.259 |
| Depression | 2.1 [10.7] | 4.3 [10.6] | 0.785 |
| Obstructive sleep apnea | 2.2 [6.8] | 4.1 [11.0] | 0.530 |
| Ciliary dyskinesia | ---- | 3.9 [10.6] | ---- |
| GERD | 2.1 [9.4] | 5.0 [11.2] | 0.451 |
| Disease characteristics: | |||
| Nasal polyposis | 7.8 [10.0] | 2.1 [10.5] | 0.066 |
| Prior sinus surgery | 2.1 [10.6] | 7.1 [10.1] | 0.121 |
| Septal deviation | 2.1 [11.2] | 4.4 [10.5] | 0.283 |
| Turbinate hypertrophy | 3.3 [10.0] | 4.0 [10.8] | 0.654 |
| Corticosteroid dependency | 2.6 [8.6] | 4.1 [10.9] | 0.521 |
| Age and baseline CRS severity measures: | Rs (p-value) | ||
| Age | 0.076 (0.561) | ||
| SNOT-22 total score | 0.004 (0.973) | ||
| RSDI total score | 0.047 (0.722) | ||
| Computed tomography score | 0.353 (0.005) | ||
| Endoscopy score | 0.116 (0.373) | ||
| Olfactory specific measures: | |||
| SIT-40 change score | 0.180 (.185) | ||
| SNOT-22 Q#21 change | −0.488 (<0.001) | ||
| RSDI physical subdomain Q#7 change | −0.436 (<0.001) |
SD, standard deviation; AERD, aspirin exacerbated respiratory disease; GERD, gastroesophageal reflux disease; SNOT-22, 22-item SinoNasal Outcome Test; RSDI, Rhinosinusitis Disability Index; QOD, Questionnaire for Olfactory Disorders; NS, negative statements; SIT-40, Smell Identification Test-40; Q, question item
We then examined the likelihood of a patient achieving the minimal clinically important difference (MCID) in QOD-NS after ESS. As previously described, we used ½ the standard deviation of the QOD-NS at baseline or for this study, an improvement of at least 6.5 points. Twenty-two patients had baseline pre-operative QOD-NS scores of 45 or greater. They had relatively good olfactory-specific QOL at baseline and were unable to improve by 7 points. Among the remaining 39 patients with relatively poor olfactory-specific QOL, 21 patients (53.8%) improved QOD-NS by at least one MCID, 4 patients (10%) had worsening QOD-NS by at least one MCID and the remainder were unchanged.
DISCUSSION
Olfactory dysfunction affects up to 80% of patients with CRS1, yet remains an enigma to most rhinologists. The relationship between objective measures of olfaction and the impact of olfactory loss upon QOL is not well studied. It is difficult to directly extrapolate objective deficits to a patient’s perception of smell and how it impacts their day to day function and QOL. Olfaction is critical to overall social functioning and pleasurable activities such as eating, and simple objective measures may not accurately reflect the true impact of olfactory loss. This may also explain why olfactory loss is commonly associated with other co-morbidities such as depression6. The development of olfactory-specific QOL instruments, such as the QOD-NS, is critical to improve our understanding of this complex relationship. Another important factor regarding the utility of the QOD-NS is its ability to discriminate among patients with anosmia, hyposmia and normosmia as determined by SIT-40 (Table 2). Simple questions regarding olfaction from common CRS-specific instruments are able to identify anosmics, but cannot differentiate between normosmics and hyposmics.
When examining baseline demographic factors and comorbidities that could potentially impact olfaction, our study found that olfaction-specific QOL is worse in patients with steroid dependency, polyps and comorbid allergy. Prior studies have shown that objective olfaction is worse in patients with eosinophilia7, nasal polyps, older age, asthma and smoking8. While we did not find age, asthma or smoking status to correlate with QOD-NS, there may be subtle differences between correlations among subjective and objective olfaction as mentioned above. Additionally, some of our variables, such as smoking status, were recorded as yes or no. While this study did not demonstrate statistical significance (p=0.098), further studies investigating quantification of smoke exposure may be worthwhile9.
With regard to CRS and olfactory specific metrics, we found that the QOD-NS correlates strongly with other olfactory-specific subjective and objective measures. QOD-NS also correlates with CRS disease severity measures of CT, endoscopy and sinus-specific QOL, but not as strongly. Others report that objective olfaction correlates to CRS specific metrics of endoscopy and CT, but not RSDI, CSS or SF3610,11. These traditional CRS-specific QOL instruments have potentially underweighted the importance of olfaction. Most questionnaires have a single question regarding olfaction. Litvack et al10 highlighted the lack of olfactory specific QOL instruments available at that time, which may explain the lack of correlation between objective olfaction and CRS-specific QOL instruments.
In determining the success of ESS in treating CRS-related olfactory dysfunction, most previous studies have examined improvement in objective olfaction. Success rates vary depending upon the methodology used and the population studied, but range from 23%3 to 68%4. Baseline predictive factors vary among studies, but improved objective olfactory outcomes have been associated with severity of baseline olfactory loss, age less that 55 years, duration of olfactory loss less than 10 years, eosinophilia, polyps, and no prior ESS 12–16.
There have been limited reports on the impact of ESS upon subjective olfactory outcomes. We found significant improvements in olfaction-specific QOL after ESS, with the greatest gains seen in those with worse CT scores at baseline. Other baseline factors were not predictive and this may be useful in counseling patients regarding olfactory recovery. Just over half (53%) of our patients with impaired olfactory-specific QOL at baseline achieved a clinically significant improvement in QOD-NS. Improvement in QOD-NS did correlate with subjective changes in SNOT-22 and RSDI olfaction questions, but not objective olfaction as measured by SIT-40. Similar success rates (68%) in subjective olfaction were reported in patients with CRSwNP after ESS4. Katotomichelakis reported improvement in QOD-NS after ESS that did correlate with objective improvements in Threshold/Discrimination/Identification (TDI)13. In their series, they actually achieved a mean QOD-NS after ESS that was essentially perfect (50.08 out of possible 51). They had 45% normosmics at baseline, compared to 28% in our study which may be one important difference. One of the only negative studies in olfactory outcomes 17 found that while olfactory symptom scores improved after ESS, SIT-40 and other objective olfaction metrics did not. There are a number of possible explanations for the conflicting reports between olfactory-specific QOL and objective testing after ESS. Heterogeneous patient populations and varying degrees of baseline olfactory dysfunction are obvious confounding factors. Furthermore, while improvements in objective testing are typically seen after ESS, it is possible that changes are simply identifying the difference that is perceptible to a patient and not necessarily whether or not that difference impacts their overall QOL. Additionally, studies examining SIT-40 measure olfactory identification. Other studies that use Sniffin’ Sticks examine olfactory discrimination and threshold in addition to identification and it may be that olfactory QOL is linked more closely to these other areas that are not measured by the SIT-40. This remains an interesting area for further study.
CONCLUSION
Olfaction remains one of the most puzzling cardinal symptoms for rhinologists and improves the least with our current treatment strategies. Olfactory-specific QOL instruments, such as the QOD-NS, correlate more strongly with other objective and patient-reported olfactory measures and provide a more comprehensive picture of how olfactory dysfunction affects our patients with CRS and their treatment outcomes.
Acknowledgments
Dr. R. J. Schlosser is consultant for Olympus and Arrinex and received grant support from Intersect ENT, Entellus and Optinose. Dr. T. L. Smith, Dr. Z. M. Soler, Dr. J.A. Alt, and J. C. Mace are supported by a grant from the National Institutes of Health (NIH; R01 DC005805). The NIH had no role in the preparation, review, or approval of this article or decision to submit it for publication. Dr. T. L. Smith is consultant for Intersect ENT. Dr. Z.M. Soler is consultant for Olympus and received grant support from Intersect ENT, Entellus and Optinose.
Footnotes
The abstract for this manuscript was accepted for oral presentation to the American Rhinologic Society during the American Academy of Otolaryngology-Head and Neck Surgery annual meeting in Dallas, Texas, September, 25–26th, 2015.
The authors have no other funding, financial relationships, or conflicts of interest to disclose.
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