Introduction
Post-surgical olfactory dysfunction after an endoscopic endonasal
approach has been reported in several series, ranging from 0% to
10.9%(1,2). This complication is attributed to surgical resection or
excessive instrumentalization of the lateral nasal wall, especially the
superior turbinate and the mid-superior part of the middle turbinate,
areas that include olfactory epithelium(3).
Even though post-surgical olfactory dysfunction is not an uncommon
condition, its treatment remains challenging due to the limited
therapeutic options(4,5). Currently, some treatment options have been
proposed, like administration of alpha-lipoic acid, theophylline, and
corticosteroids. Nonetheless there is no gold standard therapy to treat
this condition(4,6).
Recently, olfactory training has shown promising results in improving
smell identification, discrimination and threshold for odor detection in
patients with postinfectious olfactory dysfunction(5,7–9). Also, a
systematic review and meta-analysis published by Pekala et al. 2016,
suggests that it may be an effective treatment for olfactory dysfunction
due to multiple etiologies(6).
Additionally, it has been reported that olfactory training can induce
reorganization in functional connectivity networks in major olfactory
areas(8,10,11). Nevertheless, no study has evaluated the effect of
olfactory training in patients with post-surgical olfactory dysfunction.
The primary objective of this pilot study is to assess the effect of
olfactory training in patients with post-surgical olfactory dysfunction
using fMRI, while patients undergo an olfactory stimulation protocol.
Additionally, as a secondary objective, the effect of olfactory training
in olfactory identification was assessed using “Sniffing Sticks
Screening Test”.