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

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.