Lateralized olfactory difference in patients with a nasal septal deviation before and after septoplasty*

Patients with a smell disorder and less often, healthy people, exhibit an olfactory difference between the two sides of the nose. Higher olfactory thresholds are correlated with the obstructed side of a nasal septal deviation (NSD). With this prospective study we sought to investigate if a NSD compromises the olfactory identification.

Thirty patients with nasal obstruction due to a NSD were recruited. The patients were listed for primary septoplasty with or without radiofrequency reduction of the inferior turbinates. Pre- and postoperatively, patients were assessed by visual analogue scales for symptoms and by the bilateral nasal spirometry (nasal partitioning ratio-NPR) for the side/degree of obstruction. Olfactory identification was tested separately for each nasal cavity by means of the 12 item Sniffin Sticks test (12-SS test) and a 3-point difference between the nasal sides was considered significant.

The mean age of patients (25 males/5 females) was 33 years (range 17-52). No complications or anosmia were reported postoperatively. Subjective hyposmia, nasal obstruction and the NPR were reduced (p<0.001). Significant lateralized differences were present in 20% and 13% of patients before and after septoplasty respectively; the change was not significant (p=0.754). Patients with a significant lateralized olfactory difference had a greater NPR pre- (p=0.031) but not postoperatively (p=0.783). The sides of obstruction and worst olfactory performance did not differ in these patients before surgery.

Olfactory identification may be compromised on the convex side of a large NSD. Post-operatively, patients exhibit a lateralised smell identification difference as often as healthy people. The effect of a clinically significant NSD on the different aspects of olfactory performance warrants further study.