Olfactory Outcome After Endoscopic Sinus Surgery in Chronic Rhinosinusitis

Background: Olfactory dysfunction is one of the major symptoms of CRS. Olfactory dysfunction affects the quality of life. Endoscopic sinus surgery is surgical modality of treatment in the failed medial therapy. Assessment of olfaction in patients undergoing endoscopic sinus surgery is essential to know the impact on olfaction. Objective: To assess the olfaction before and after Endoscopic sinus surgery. Methods: This is a prospective study. Total 45 Patients were included in this study based on the inclusion and exclusion criteria. Diagnostic nasal endoscopy and CT scan were done preoperatively. Olfaction was assessed in all patients preoperatively, postoperatively at 1month and 3 months using olfactory testing tool. Results: There were 45 patients of both gender 57.78% were females and 42.22% were males. The mean age of patients in our study was found to be 39.82±6.264 years. Most of these patients were in fourth decade of life. Of 45 patients 75% had symptoms of hyposmia/anosmia before surgery. Average Lund Mackey score for CT scan findings was found to be 13.42 ± 3.1. The patients were assessed postoperatively at 1st month and 3rd month using olfactory testing tool. The mean composite olfactory score was 5.83±2.89 preoperatively increased to 8.28± 2.33 at 1 month and 10.12 ±1.11 at 3 months, this difference was found to be statistically significant (p < 0.001). All patients mean olfactory scores improved postoperatively. The mean composite olfactory scores improved following endoscopic sinus surgery by 3.5 in Anosmic patients, 2.22 in Hyposmic patients and 1.04 in Normosmic at 1 month. Whereas at 3 month 6.65, 3.22 and 1.95 in Anosmic, Hyposmic and Normosmic patients, respectively. The study was an attempt to assess the olfaction preoperatively and postoperatively in patients undergoing ESS. Conclusion: The evaluation of olfaction in patients undergoing endoscopic sinus surgery showed improvement in olfactory outcome following the surgery in patients with CRS. As CRS patients 61 to 69% of patients have a reduced sense of smell. Approximately two thirds of cases are due to the sinonasal disease. Olfactory dysfunction as result of sinonasal disease is unlikely to improve spontaneously without treatment.


Introduction
Olfaction is a special sense of smell, which is perceived in the olfactory region of the nasal cavity and helps in enjoying the taste of food. The anatomic state of nasal epithelium and the status of the peripheral and central nervous system determine the quality and the intensity of perception [1]. The perception of odors adds a quality to life. Odors are part of our everyday life, from pleasures of perfume to satisfaction of toast and coffee [2]. Olfaction survives many purposes from detection of hazards, sexual behavior, flavors of food. The olfactory system impairment has got significant impact on quality of life. Among the people presenting with olfactory disturbances has got changes in appetite or body weight and also affects psychological well-being. Significant psychological disruption and feeling of physical and social vulnerability occur by the olfactory disturbances. Anosmia is an inability to detect olfactory sensations while hyposmia is reduced ability to perceive odors [2].
Chronic rhinosinusitis (CRS) related olfactory dysfunction is common with prevalence ranging from 48% to 83% .It is known that medical therapy improves olfactory dysfunction in CRS. For patients failing medical therapy, endoscopic sinus surgery is performed. Addressing the patients with olfactory impairment is important, as affects the quality of life. Endoscopic sinus surgery (ESS) is the preservation of existing structures by performing limited surgery [3]. ESS is widely used in chronic rhinosinusitis and nasal polyposis. The primary objective of Endoscopic Sinus Surgery is to restore paranasal sinus function by reestablishing the physiological pattern of ventilation and mucociliary clearance [4]. Olfactory disturbances are one of the complications of sinus surgery. Kimmelman tested 93 patients before and after sinus surgery, 34% patients had decreased olfactory ability [5]. As olfactory dysfunction is difficult to express by patients. Objective assessment of olfactory disturbance is necessary to know outcome of ESS on olfaction. Connecticut Chemosensory Clinical Research Centre Olfactory (CCCRC) test which is composed of threshold testing and odor identification test, it is done to know sinus surgery impact on olfaction [6,7]. Hence, there is a need for study to know the impact of ESS on olfaction.

Objectives
To assess the olfaction before and after ESS. ketchup, onion, wood shavings and tobacco will be used. The substances (color coded) will be kept in glass tubes, the uncapped tubes will be placed approximately 1 cm from the nostril for 3

Materials and Methods
seconds. The patient should be told to sniff normally and identify the odor presented. Two chances will be given to identify one odor. Patient should identify the four randomly offered odors.
The interval of 30seconds is given for successive presentation.
The correctly identified odors will be taken as odor identification score of that nostril. Final odor identification score of an individual calculated by combining the score of both the nostrils.
For odor threshold testing, test odorants like butanol-1, peppermint oil, clove oil, lemon oil will be used. The test uses an aqueous dilution series of butanol, in which highest concentration 4% labeled as solution 1 and lowest being solution 9. The successive dilution of butanol differs by a factor 3.The sterile water will be taken as test control. The test will be started with lowest concentration. The patient will be given two glass tubes at a time, one with sterile water, other with odorant (solution 1-9).
Then patient asked to identify the tube that smells stronger. Four consecutive correct responses will lead to the termination of test.
If response is incorrect, the next higher concentration will be given after a gap of 15 seconds. The patient will be allowed to answer

Statistical Analysis
The data was entered in an excel spreadsheet and analyzed using IBM SPSS version 20. The descriptive statistics were presented as mean and standard deviation for the quantitative variables whereas in numbers and percentages for qualitative variables. Population pyramid was used to represent age distribution according to sex and pie chart was used represent the distribution of subjects according to presenting symptoms. The olfactory scores were compared preoperatively with postoperatively at 1 month, preoperatively and postoperatively at 3 months using the Wilcoxan Signed Rank test.
The mean olfactory scores of preoperative period postoperatively at 1 month and 3 months were compared using Friedman test. The results were considered significant at p value of 0.05 (two-tailed).

Results
There were 45 patients in the study. In our study, the preoperative mean olfactory score was 5.83, which improved to 8.28 and 10.12 in the postoperative period at 1 st month and 3 rd month, respectively. This was found to be statistically

Conclusion
The evaluation of olfaction in patients undergoing endoscopic sinus surgery shows the improvement in olfactory outcome following the surgery in patients with CRS. As CRS patients 61 to 69% of patients have a reduced sense of smell [17]. Approximately two thirds of cases are due to the sinonasal disease. Olfactory dysfunction is an increasingly recognized condition with reduced quality of life [18]. Impairment secondary to sinonasal disease is most commonly caused by CRS with or without polyposis.
In addition to the mechanical obstruction of odorant to the olfactory cleft caused by polyps and edema, impairment in CRS is also attributed to the inflammatory cytokine mediated olfactory dysfunction. So, the olfactory dysfunction as result of sinonasal disease is unlikely to improve spontaneously without treatment.
The olfaction was assessed objectively preoperatively and following surgery at 1 month and 3 months which showed the statistically significant improvement in olfactory scores in all patients. ESS showed significant improvement in olfactory outcome. As CCCRCT olfactory test is to perform and helps to assess the outcome of ESS.
Alone this test does not help to know the postoperative status. In addition to this test anterior rhinoscopy examination and nasal endoscopy assess the surgery outcome more accurately. The study was an attempt to assess the olfaction preoperatively and postoperatively in patients undergoing ESS.