Correlation Between Olfactory Dysfunction Caused By Nasal Septal Deviation And Olfactory Bulb Volume Alteration

Objective:To investigate the correlation between olfactory dysfunction caused by nasal septum deviation and olfactory bulb volume alteration.Moreover,given the fact that nasal septal deviation is a lateralized disease,we further investigate whether such correlation is specific to a certain side.Methods:Data were collected from NSD patients who came up to our department from March,2018 to December,2019.All subjects(patients and healthy volunteers)went through rhinoscope examination,CT scan for the sinonasal section and MRI examination for the olfactory bulb as well as the olfactory tract.Sniffin's Sticks tests were used for psychophysical assessment of the olfactory function.Statistics were processed by SPSS21.Results:A total of 22 subjects got involved in our research,including 13 patients(4 female,9 male)and 9 volunteers(5 male,4 female),average age was 34.0±16.7yrs for the patients and 29.6±7.4yrs for the volunteers.Data including smoking condition,alchohol usage,steroid spray usage as well as duration for olfactory dysfunction were collected from all subjects.No significant correlation were found between any of the above mentioned factors and olfactory function or OB volume.In accordance with previous literature,the majority of patients exhibited an overall decreased olfactory function(as judged for the better side: normosmia in 2 patients,hyposmia in 8 patients,anosmia in 3 patients).OB volumes for patients were significantly smaller when compared to healthy subjects(22.8±10.4mm3 and 43.3±9.5mm3 respectively).As expected,olfactory function(as assess by Sniffin's Sticks test score)as well as olfactory bulb volume decreased significantly at the narrower side(p<0.001).In terms of each test namely Threshold,Discrimination and Identification,scores were significantly lower in patient group(p<0.01).In addition,patients with right NSD scored significantly lower in identification(p=0.032).When correlating relative volumes(wider minus narrower side)and the side of deviation,subjects presented with a right-sided deviation showed significantly larger differences in volumes than those whose left sides were narrower(p<0.042).Conclusion:Our study clearly highlights that septal deviation leads to decreased olfactory function and OB volume reduction.In addition,lateralized differences in relative volumetric measurements of OB are more significant when the narrower side is the right side.