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.