Olfactory Outcomes after Endoscopic Sinus Surgery for Chronic Rhinosinusitis: A Meta-analysis

Otolaryngol Head Neck Surg. 2016 Dec;155(6):936-948. doi: 10.1177/0194599816664879. Epub 2016 Aug 30.


Objective: To use combined pre- and postsurgical olfactory outcomes to assess the impact of endoscopic sinus surgery on chronic rhinosinusitis-related olfactory impairment.

Data sources: CINAHL, Cochrane, OVID, EMBASE, PubMed, and SCOPUS. Each database was searched from inception up to October 2015.

Review methods: Studies were included that reported subjective or objective olfactory data in chronic rhinosinusitis patients before and after endoscopic sinus surgery.

Results: Thirty-one studies were used in the meta-analysis. Weighted mean differences of olfactory measures demonstrated significant improvement in mixed CRS patients (those with and without polyps) through visual analog scales (-0.83, P = .001), altered taste/smell item on Sinonasal Outcome Test (-1.32, P < .00001), 40-item Smell Identification Test (3.49, P = .0010), and Sniffin' Sticks identification (0.34, P = .03). Chronic rhinosinusitis mixed patients demonstrated nonsignificant improvements via Sniffin' Sticks threshold (1.60, P = .16) and Brief Smell Identification Test (0.20, P = .32). When separated, polyp patients and dysosmic patients experienced the highest levels of olfactory improvement. Polyp patients improved by 7.87 (P = .006) on the 40-item Smell Identification test, 11.54 (P < .0001) with the Sniffin' Sticks total score, and 2.57 (P < .00001) through Sniffin' Sticks identification. Dysosmic patients improved by 5.75 via the 40-item Smell Identification Test (P = .0001).

Conclusion: Endoscopic sinus surgery improves nearly all subjective and objective measures of olfaction in chronic rhinosinusitis patients. Patients with nasal polyposis or preoperative olfactory dysfunction improve to a greater degree.

Keywords: chronic rhinosinusitis; meta-analysis; olfaction; sinus surgery; sinusitis; smell.

Publication types

  • Meta-Analysis
  • Review
  • Research Support, N.I.H., Extramural

MeSH terms

  • Chronic Disease
  • Humans
  • Laryngoscopy* / methods
  • Nasal Polyps / complications
  • Nasal Polyps / surgery
  • Olfaction Disorders / rehabilitation
  • Paranasal Sinuses / surgery
  • Quality of Life*
  • Rhinitis, Allergic / surgery*
  • Risk Assessment
  • Risk Factors
  • Sinusitis / surgery*
  • Surveys and Questionnaires
  • Treatment Outcome