Curr Opin Otolaryngol Head Neck Surg. 2012 Feb;20(1):29-32. doi: 10.1097/MOO.0b013e32834dfb3d.

Olfactory improvement after endoscopic sinus surgery.

Rudmik L1, Smith T 2

• 1Rhinology and Sinus Surgery, Division of Otolaryngology – Head and Neck Surgery, Department of Surgery, University of Calgary, Calgary, Alberta, Canada
• 2Division of Rhinology and Sinus Surgery, Oregon Sinus Center, Department of Otolaryngology – Head and Neck Surgery; Oregon Health and Science University, Portland, Oregon.

PURPOSE OF REVIEW:

Olfactory dysfunction is a common complaint in patients with chronic rhinosinusitis (CRS). The purpose of this article is to review the current evidence on the impact of endoscopic sinus surgery (ESS) on CRS-related olfactory dysfunction.

RECENT FINDINGS:

The recent literature suggests that olfactory outcomes after ESS are challenging to predict. Some evidence supports a positive impact of ESS on improving olfactory outcomes in patients with preoperative nasal polyposis and anosmia. However, despite improvements in smell, most of these patients remain with severe hyposmia. One study suggests ESS has no impact on olfactory outcomes.

SUMMARY:

CRS-related olfactory dysfunction is a complex clinical scenario and it is challenging to predict improvement following ESS. CRS patients with anosmia and nasal polyposis preoperatively may have a higher likelihood of olfactory improvement following ESS.

PMID: 22143338 [PubMed - indexed for MEDLINE] PMCID: PMC3343214

Free PMC Article

From the article

Early studies supported the role of ESS to improve CRS-related olfactory dysfunction. However, several recent larger prospective studies have improved our understanding of the impact of ESS on CRS-related olfactory dysfunction and have begun to elucidate the predictive factors associated with olfactory improvement.

In 2009, Litvack et al. reported a prospective trial of 111 patients with olfactory impairment undergoing ESS for medically refractory CRS.

Absolute SIT scores were categorized into olfactory severity categories based on robust gender-adjusted, normative data

• normosmics:
• men with SIT scores 34-40 and
• women with SIT scores 35-40;
• microsmics/hyposmics:
• men with SIT scores 19-33 and
• women with SIT scores 19-34;
• anosmics: men and women with SIT scores 6-18.
• Patients with SIT scores 0-5 were categorized as malingering and removed from the analyses.

The results demonstrated that olfactory impairment

• improved following ESS for anosmic patients but
• not for patients with hyposmia.

The improvements for anosmic patients were stable after 1 year follow-up.

They hypothesized that

• anosmic patients typically had a mechanical obstruction to the olfactory cleft which was amenable to surgical removal
• hyposmic patients which likely suffered from a multi-factorial etiology of olfactory impairment with chronic neuroepithelial inflammation and damage which was less amenable to ESS optimization.

The only predictive factor for post-ESS olfactory improvement was the presence of nasal polyposis.

Factors such as

• age,
• allergy status,
• ASA intolerance, and
• history of prior ESS

were not predictive factors.

A large prospective 2008 study by Pade et al. evaluated 206 patients with olfactory impairment who elected ESS for CRS. They demonstrated that

• 23% of patients received improvement,
• 68% received no change, and
• 9% got worse after ESS.

The results suggested that the presence of nasal polyposis and eosinophilia predicted olfactory improvement

In contrast to the above studies, a recent 2008 study by Jiang et al. evaluated the impact of ESS on olfactory outcomes in patients with medically refractory CRS.

• They demonstrated that ESS had no impact on olfactory improvement.

In a subsequent 2009 article by Jiang et al. they attempted to identify predictive factors for olfactory improvement following ESS. The results demonstrated no predicative correlation between olfactory improvement following ESS and the

• degree of nasal obstruction,
• severity of CRS,
• presence of nasal polyposis, or
• allergy status.

In 2010, Soler et al. evaluated the impact of histologic markers on olfactory outcomes following ESS.

• They identified that olfactory impairment correlated with higher degrees of tissue eosinophilia and basement membrane thickening.
• However, after controlling for nasal polyposis, none of the inflammatory histologic markers predicted olfactory improvement following ESS.
• Furthermore, 75% of anosmic patients received olfactory improvement after ESS, however, despite improvement, most of these patients remained with residual severe hyposmia.

This suggests that most patients with CRS and olfactory impairment suffer from some form of permanent neuroepithelial injury.

The evidence suggests that

• patients with anosmia and nasal polyposis may have a higher chance of olfactory improvement following ESS, whereas
• hyposmic patients without nasal polyposis have a lower likelihood to improve following ESS.

Future research will need to further investigate the role of histologic markers as predictive factors in olfactory improvement following ESS.

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Otolaryngol Head Neck Surg. 2009 Mar;140(3):312-9. doi: 10.1016/j.otohns.2008.12.006.

Does olfactory function improve after endoscopic sinus surgery?

Litvack JR1, Mace J, Smith TL.

Author information

Abstract

OBJECTIVE:

To examine the impact of endoscopic sinus surgery (ESS) on olfactory impairment in patients with chronic rhinosinusitis (CRS) over intermediate and long-term follow-up. We hypothesized that patients with mild olfactory dysfunction (hyposmia) would benefit from ESS, whereas patients with severe olfactory dysfunction (anosmia) would not.

STUDY DESIGN:

Prospective, multi-institutional cohort study.

SUBJECTS AND METHODS:

A total of 111 patients presenting for ESS for treatment of CRS were examined preoperatively, and at 6 and 12 months postoperatively. Demographic, comorbidity, and Smell Identification Test (SIT) data were collected at each time point. Univariate and multivariate analyses were performed.

RESULTS:

The prevalence of gender-adjusted olfactory dysfunction prior to surgery was 67.5 percent.

Surprisingly,

• hyposmic patients did not significantly improve after surgery. In contrast,
• patients with anosmia significantly improved after ESS
• baseline, 6-month SIT scores:
• anosmia: 9.7 +/- 2.0,
• hyposmia: 21.3 +/- 11.2; P = 0.001.

Improvement was sustained at 12-month follow-up (21.7 +/- 10.7; P = 0.001). Multivariate linear regression analysis showed that baseline olfactory category and nasal polyposis were significantly associated with improvement in postoperative olfactory function (P = 0.035, P = 0.002).

CONCLUSION:

Contrary to our hypotheses, patients with severe olfactory dysfunction significantly improved after ESS and sustained improvement over time, whereas patients with mild olfactory dysfunction did not.

Comment in

• Does olfactory function improve after endoscopic sinus surgery? [Otolaryngol Head Neck Surg. 2009]

PMID: 19248934 [PubMed - indexed for MEDLINE] PMCID: PMC2668517

Free PMC Article

From the Discussion

In contrast to our initial hypothesis, we found that anosmic patients improved after ESS whereas hyposmic patients did not.

• We had suspected that hyposmics had anatomic obstruction secondary to their disease that would benefit from surgical removal whereas anosmic patients would have underlying multifactorial olfactory impairment including both physical obstruction of the olfactory cleft and direct inflammation of the neuroepithelium that would not benefit from surgical treatment.
• Given our findings that anosmics improved whereas hyposmics did not, we hypothesize that this difference in olfactory outcomes occurred, at least in part, as a result of nasal polyposis causing anosmia. Since patients with nasal polyps and anosmia likely have complete obstruction of the olfactory cleft, surgical resection of this local inflammatory process improved olfaction. In fact, anosmic patients with nasal polyposis improved significantly more than patients without nasal polyposis.

Interestingly, this interaction between nasal polyposis and other variables in CRS and olfactory outcomes studies has been noted by us and others in prior studies.6,19 The potential for nasal polyposis to interact with other variables should be addressed in the analyses of outcomes data and should be investigated in future studies.

Table I

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668517/table/T1/

Patients' baseline demographic data and clinical characteristics by olfactory status (n=111).

Normosmics (n=36) Hyposmics (n=56) Anosmics (n=19) p-value

Age (mean ± SD) 42.2 ± 13.2 50.2 ± 15.3 50.9 ± 13.1 0.028

Gender %(n)

Male 44.4% (16) 46.4% (26) 47.4% (9)

Female 55.6% (20) 53.6% (30) 52.6% (10) 0.974

Clinical characteristics %(n)

Nasal polyposis 27.8% (10) 28.6% (16) 73.7% (14) 0.001

Asthma 38.9% (14) 30.4% (17) 73.7% (14) 0.004

Aspirin intolerance 2.8% (1) 7.1% (4) 26.3% (5) 0.012

Allergic rhinitis 30.6% (11) 26.8% (15) 5.3% (1) 0.096

Septal deviation 33.3% (12) 30.4% (17) 10.5% (2) 0.170

Hypertrophy turbinate 8.3% (3) 8.9% (5) 5.3% (1) 0.878

Prior sinus surgery 52.8% (19) 66.1% (37) 63.2% (12) 0.435

Smoker 5.6% (2) 5.4% (3) 0(0) 0.582

Medication Usage %(n)

Systemic 19.4% (7) 23.2% (13) 31.6% (6) 0.599

corticosteroids

Disease Severity Measures (mean ± SD)

Lund-MacKay

CT scores 10.1 ± 6.0 11.8 ± 6.4 18.4 ± 5.0 <0.001

Lund-Kennedy 

endoscopy score 5.1 ± 5.0 6.1 ± 4.4 9.4 ± 5.0 0.006

Table II

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668517/table/T2/

Olfactory scores in patients with and without topical corticosteroid use

Topical corticosteroid use No topical corticosteroid use p-value

Normosmic (mean ± SD)

Preoperative 35.8 ± 1.5 (n=23) 35.7 ± 1.1 (n=13) 0.974

12 month postoperative 34.8 ± 3.2 (n=27) 34.0 ± 4.8 (n=9) 0.886

Hyposmic (mean ± SD)

Preoperative 28.3 ± 4.8 (n=35) 29.7 ± 3.9 (n=21) 0.336

12 month postoperative 29.3 ± 6.1 (n=43) 29.8 ± 6.5 (n=13) 0.460

Anosmic (mean ± SD)

Preoperative 10.0 ± 2.1(n=12) 9.1 ± 1.8 (n=7) 0.384

12 month postoperative 22.6 ± 10.2 (n=17) 20.3 ± 12.2 (n=2) 0.421

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Am J Rhinol Allergy. 2013 Jul-Aug;27(4):e96-100. doi: 10.2500/ajra.2013.27.3939.

Objective olfactory outcomes after revision endoscopic sinus surgery.

Hsu CY1, Wang YP, Shen PH, Weitzel EK, Lai JT, Wormald PJ.

• 1Department of Otolaryngology, Kuang-Tien General Hospital, Taichung, Taiwan.

Abstract

BACKGROUND:

Patients who suffer from hyposmia and anosmia report a negative effect on their overall quality of life. Smell disturbance of patients with chronic rhinosinusitis (CRS) can improve after endoscopic sinus surgery (ESS). Although several studies have shown that 50-83% of patients may notice an improvement in olfactory function after ESS, the olfactory improvement after revision ESS (RESS), especially by objective measurements, is still lacking.

METHODS:

Olfactory function was assessed by the traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT-TC, forced choice, score range 0 - 40) preoperatively and postoperatively, recorded as smell identification test (SIT) score. Olfactory outcomes from anosmia to hyposmia/normosmia, or from hyposmia to normosmia, were considered as "improvement." Postoperative assessments were divided into two periods: period 1 (P1) is defined as >6 but <12 months postoperatively; period 2 (P2) is defined as >12 but <24 months postoperatively.

RESULTS:

32 patients with smell disturbance preoperatively (period 0 [P0]) and confirmed by UPSIT-TC were enrolled into this study.

• Mean SIT score pre operation was 13.3;
• mean SIT score at 6 - 12 months post operation was 18.6;
• mean SIT score at 12 - 24 months post operation was 20.4.

The presence of

• nasal polyps blocking the olfactory cleft were associated with better olfaction improvements (p < 0.05) as was
• the degree of mucosal swelling.

The overall improvement rates were

• 44.8% at 6 - 12 months post operation
• 47.8% at 12 - 24 months post operation.

CONCLUSION:

RESS resulted in objective evidence of olfactory improvement in approximately one-half of our cohort over 16 months of follow-up and offers a treatment option for an otherwise poor prognosis condition.

PMID: 23883800 [PubMed - indexed for MEDLINE]

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Version: 6.1.2018

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