Effects of Endoscopic Sinus Surgery on Olfactory Bulb Volume among Patients with Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis.

Background: Endoscopic sinus surgery (ESS) could significantly improve olfactory function among patients with chronic rhinosinusitis (CRS). This study aimed to perform a meta-analysis to evaluate the effect of ESS on the olfactory bulb volume (OBV) among patients with CRS.

Methods: A systemic search of PubMed, Medline, Embase, Web of Science, and other databases was conducted to identify studies assessing OBV changes in patients with CRS after ESS utilizing magnetic resonance imaging.

Results: A total of four studies with 168 participants were included. Comparing the changes in OBV of patients with CRS before and after surgery within 3-6 months, the ESS significantly improved the overall OBV ( = 0.005, I= 66%), with the left OBV increased by 5.57mm ( = 0.84, I= 0%), and the right OBV increased by 8.63mm ( = 0.09, I= 53%). A difference in OBV persists between healthy controls and patients with CRS 3-6 months after ESS. The overall OBV of patients with CRS after ESS was significantly smaller than controls (mean difference = -3.84,  = 0.04), with a mean difference of 4.13mm on the left side ( = 0.72, I= 0%), and a mean difference of 3.22mm on the right side ( = 0.0001, I= 89%).

Conclusions: ESS significantly increases the OBV among patients with CRS.