Since the joy of foods and/or beverages is highly correlated with their odor, any degree of olfactory dysfunction negatively impacts one's sense of well-being and content 12. Not only do olfactory impairments alter one's appetite, body weight, psychological well-being, and quality of life 3, but they also compromise one's safety when a certain odor should raise the alarm in such different cases as spoiled food, leaking natural gas, or airborne pollutants 4. Indeed, during fire alarms, those with a more intact sense of smell can perceive danger earlier and flee the scene more swiftly 5. In short, loss or distortion of the olfactory function can even lead to mortality 67.

Patients undergoing open rhinoplasty may sustain postoperative olfactory complications; it should come as no surprise that olfactory impairments are a great concern for the surgeon and/or the patient 89. Determining a timetable for the recovery of the olfactory function can, therefore, pave the way for a better communication between the surgeon and the patient 10 and enhance the latter's trust in esthetic and/or reconstructive nasal surgery 11.

Unfortunately, there is a dearth of data in the existing medical literature on olfactory impairments after open rhinoplasty, but we do know that surgical trauma, mucosal swelling, olfactory nerve paralysis and blood clots within the nasal cavity are most contributing factors 1213.

We sought to determine the time required for the olfactory function to revert to its preoperative levels after open rhinoplasty.

The olfactory function shows a temporary decline following open rhinoplasty but tends to revert to its preoperative levels 6 months post surgery. This may be a reassuring answer to candidates for this kind of nasal surgery since they are likely to inquire whether the loss or decrease in their sense of smell is reversible, and, if reversible, how long it is before their sense of smell is normal again 24.

One week after open rhinoplasty, anosmia was present in 87.5% of our patients, and the rest exhibited moderate to severe hyposmia. In other words, almost all the patients were anosmic shortly after open rhinoplasty. By postoperative week 6, however, anosmia had downgraded to mainly mild to moderate levels of hyposmia. All our patients had regained their preoperative olfactory function levels by postoperative month 6; most were normosmic and a few were mildly hyposmic.

In a study of 93 patients undergoing various types of nasal surgery, including ethmoidectomy, polypectomy, Caldwell-Luc procedure, open reduction of nasal fracture, closed reduction of nasal fracture, rhinoplasty, and septoplasty, 34% of the patients experienced degrees of decline in their olfactory function. In 1% of the patients, anosmia persisted for a long time 15. In a review of 200 rhinoplasty patients, Champion 25 noted that 10% complained of temporary anosmia.

The reason for the differences between the results of previous studies and those in the present study can be the different types of nasal surgery covered in the investigations: while some procedures may cause direct trauma to the olfactory neuroepithelium itself or distortion of the intranasal anatomy, some surgeries such as esthetic open rhinoplasty have a very mild or even no such direct impacts.

Our results, demonstrating a complete return of the olfactory function to the baseline values, do not chime in with those in the Heywood et al. study, which showed mainly incomplete degrees of improvement 22.

It is noteworthy that among the authors who believe that the olfactory function will return to its pre-surgery values, there is no consensus regarding the time required for this improvement. Indeed, such different time periods as less than 6 months 26, a minimum of 6 months, 27, and longer periods up to 18 months 25 have been mentioned. Indubitably, however, a meticulous preoperative medical history check and physical examination in conjunction with proper paraclinical tests can not only determine the preoperative status of the olfactory function but also enable the surgeon to provide the patient with more definite answers as regards queries about time 13.

In our study, gender was not a predictor of the amount of the olfactory acuity loss; the reason may lie in the fact that our sample size was limited. In contrast to our studies, some investigators have reported gender as one of the predictors of olfactory impairment, in conjunction with some other variables such as use of general anesthesia and amount of swelling in the nasal mucous membrane 1528.

A proportion of our patients had mild hyposmia at postoperative month 6, but all of them had this condition before the surgery as well. As these patients are not usually aware of their impaired olfaction preoperatively, they may wrongly attribute their remained distorted sense of smell to the surgical procedure. Documentation of the preoperative olfactory function before nasal surgery can preclude such postoperative claims 1.

Olfaction is susceptible to temporary disorders, following a congestion or edema, as the olfactory nerve fibers cross through multiple small foramina in the cribriform plate of ethmoid and crista galli 4. These indirect causes may also include indirect disturbances engendered by pharmacologic agents or mucosal edema or other processes, hence the general rule: "All types of nasal surgery can potentially worsen the olfactory function" 15, even in the absence of direct trauma to the olfactory nerve or even nasal mucosa 5. External cosmetic rhinoplasty is no exception.

The present study had some limitations. The sample size was small, and there was no access to any published data on the sensitivity and normal ranges of the Iranian population with respect to the smell test utilized. Another drawback of the present study was the fact that odor identification is strongly dependent on familiarity with these odors 29, and it is essential that culture be taken into consideration when developing smell tests specific for each country 23. As result, a modified smell test had to be used for our samples, all of whom were Iranian. Although our subjects' high preoperative scores attest to our meticulous selection of relatively identifiable (and pleasant) odors, this use of a modified smell test precluded a comparison between our results and those reported previously. The present study did not investigate the possible predictors of postoperative olfactory change, and nor did it include variables such as "medications", "durations of packing period", "procedures", and "duration of decreasing gross inflammation".

The temporary decline in the olfactory function following open rhinoplasty can be expected to fully resolve by postoperative month 6.