|Year : 2018 | Volume
| Issue : 2 | Page : 36-39
Taste disturbance following microlaryngoscopic surgery
Urmila Gurung1, Yashashwi Man Anand2
1 Department of ENT-Head and Neck Surgery, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu, Nepal
2 Department of ENT, Patna Medical College and Hospital, Patna, Bihar, India
|Date of Web Publication||24-Jul-2019|
Dr. Urmila Gurung
Department of ENT-Head and Neck Surgery, Ganeshman Singh Building, Tribhuvan University Teaching Hospital, Institute of Medicine, Kathmandu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aims: Taste disturbance following microlaryngoscopic surgery (MLS), although reported, is not a commonly discussed complication. This study was conducted to assess the frequency and recovery of taste disturbances following MLS and its relation with operative time. Subjects and Methods: It was a prospective, observation study conducted in a tertiary center. Fifty-nine patients underwent MLS for benign laryngeal lesions between July 2014 and January 2016. Chemogustometry using tastants' sucrose, salt, citric acid, and caffeine was done a day before surgery, on 1st postoperative day (POD) and 3 weeks postoperatively to assess taste disturbance. The tongue compression by laryngoscope during MLS was taken as operative time. SPSS 16.0 for Windows™ was used for statistical analysis. Genderwise taste disturbance and the recovery of taste disturbance from first POD to 3rd postoperative week were analyzed using Yates's Chi-squared test. Mann–Whitney test was used to compare the mean operative time between patients with and without taste disturbance. The level of statistical significance was set at P < 0.05. Results: Eight out of fifty-nine (13.5%) patients had taste disturbance on first POD. The operative time ranged from 18 to 33 min (mean 21.3 min ± 4.89) in patients with taste disturbance while the time ranged from 10 to 20 min (mean 13.68 ± 2.33) for patients with no taste disturbance; the difference was statistically significant (P < 0.001). At 3 weeks' postoperative follow-up, only two patients (3.2%) had taste disturbance while six recovered. Conclusions: Transient taste disturbance following MLS is likely more so with longer operative time; hence, preoperative discussion about this potential risk is essential.
Keywords: Laryngoscopy, operative time, taste
|How to cite this article:|
Gurung U, Anand YM. Taste disturbance following microlaryngoscopic surgery. J Laryngol Voice 2018;8:36-9
| Introduction|| |
Microlaryngoscopic surgery (MLS) is a common otolaryngological procedure performed for both diagnostic and therapeutic indications in laryngeal pathologies. There are known complications such as minor mucosal lesions, dental injuries, dysphagia, partial tongue numbness, and hypoglossal nerve dysfunction secondary to the procedure., Transient taste disturbance has been reported as a likely complication; however, it is not commonly discussed during preoperative counseling of the patient.,, With complex phonomicrosurgical procedures needing longer operative time, it may increase the risk., The study thus prospectively assessed the frequency and recovery of taste disturbances following MLS and its relation with the operative time.
| Subjects and Methods|| |
After obtaining institutional review board approval, patients of both genders aged more than 14 who underwent MLS for benign laryngeal lesions at a tertiary care center from July 2014 to January 2016 were included in the study. Excluded from the study were those with preexisting taste and smell disorder, xerostomia, diabetes mellitus, on medications altering taste like metronidazole, lithium carbonate, tetracycline within a month of surgery, history of exposure to radiation, history of surgery involving oropharynx, tongue, tonsillectomy, and middle ear surgery.
Kleinsasser laryngoscope was used for MLS with patient placed in Boyce position after orotracheal intubation. The laryngoscope was inserted with the dominant hand whilst the nondominant hand was used to keep the lips apart. It was advanced further in the midline identifying base of tongue, vallecula, epiglottis, posterior pharyngeal wall, and arytenoids. Keeping the endotracheal tube posteriorly, the tip of the epiglottis was lifted, and the vocal cords were visualized. The laryngoscope was then fixed by means of chest fixator. Cricoid counter pressure was applied if needed. MLS procedures were done by multiple surgeons all of whom used cold steel instruments. The duration of tongue compression, i.e., time between insertion and removal of laryngoscope was documented and taken as the operative time.
To assess the taste disturbance, chemogustometry was done on a day before the surgery, on the 1st postoperative day (POD) and 3 weeks postoperatively. Four tastants – sucrose, citric acid, sodium chloride prepared in concentration of 0.1 g/mL each, and caffeine in concentration of 0.01 g/mL based on one of the concentrations used by Pingel et al. were used for taste analysis. Cotton soaked with sucrose (sweet), sodium chloride (salty), and citric acid (sour) were applied on the anterior third of the tongue (sweet on the tongue tip, sour, and salty on tongue lateral border) and caffeine (bitter) at the posterior tongue as per method adopted from Pingel et al. Patients were asked to extend the tongue while applying the tastant and identify the taste. The taste stimuli were applied randomly ending with bitter. Before application of each tastant, the mouth was rinsed with drinking water.
The means of the operative time for patients with and without taste disturbance were calculated and they were compared.
Analysis of the data was done using Software Package for Social Services 16.0 for Windows™ (SPSS Inc., Chicago, IL, USA). Genderwise taste disturbance was analyzed using Yates's Chi-square test. Mann–Whitney test was used to compare the mean operative time between patients with and without taste disturbance. The number of symptomatic patients whose taste disturbance recovered from first POD to 3rd postoperative week was analyzed using Yates's Chi-squared test. The level of statistical significance was set at P < 0.05.
| Results|| |
There were 59 patients, 37 males and 22 females, who underwent MLS procedure consecutively during the 18 months' study period. The age ranged from 15 to 80 years with the mean being 40 years. MLS was performed for vocal cord cyst in 30, vocal cord polyp in 12, laryngeal papilloma in nine, vocal cord nodule in six, one each for vallecular cyst and Reinke's edema.
None of the patients had any taste disturbance on the day before surgery. On the first POD, eight out of 59 patients (13.5%) had taste disturbance. Three patients had taste disturbances for multiple tastants invariably involving sucrose on first POD. The remaining five had taste disturbance only for sucrose. None of them had taste disturbance for caffeine [Figure 1].
Four (10.81%) out of the 37 male and four (18.18%) among 22 female patients developed taste disturbance on first POD. There was no statistical difference in the occurrence of taste disturbance between the two genders (P = 0.113).
The operative duration ranged between 10 and 33 min with the mean time being 14.73 ± 3.82 min. The operative time ranged from 18 to 33 min with mean of 21.3 min ± 4.89 in patients with taste disturbance while the time ranged from 10 to 20 min with mean 13.68 ± 2.33 for patients with no taste disturbance. The difference in the mean was statistically significant [Table 1].
Out of the eight symptomatic patients, only two had persistent taste disturbance while six recovered leaving 3.4% (2/59) of the study population with taste disturbance in 3 weeks' postoperative period. Both patients had taste disturbance to sucrose only. The recovery of taste disturbance in 3 weeks' postoperative period was statistically significant [Table 2].
|Table 2: Recovery of taste disturbance from postoperative day 1 to 3 weeks' postoperative period|
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| Discussion|| |
Taste function plays a great role in food selection, nutrition, and overall health. Taste abnormalities can have an unfavorable impact on a person's health. Undesirably, it can develop following several surgical procedures involving the oropharynx including tonsillectomy, middle ear surgery, endocrine disorders like diabetes mellitus, aging, medications, and even intubation.,,, Its occurrence following MLS has also been reported from 2.9% to 18% in the literature in case reports and some prospective studies.,,,
In this study, the mean age of 40 years was lower as compared to other studies in which the mean age ranged from 54 to 59 years.,, The relatively younger study population in our study may be because we dealt exclusively with benign lesions which was not the case in other studies. Gender distribution of patients, i.e., 3:2 male female ratio in this study was comparable to other studies.,,,
Since none of the patient had taste disturbance on the day before surgery, any preexisting taste disturbance was excluded. On the first POD, eight out of 59 patients (13.5%) had taste disturbance identified on chemogustometry. Landis et al. also noted 10% taste disturbance post-MLS on first POD chemogustometry in a prospective study of 33 patients which included 11 malignant laryngeal lesions. The frequency was noted to be as high as 18% by Rosen et al. in 56 patients having suspension laryngoscopy for phonomicrosurgery. This result was based on questionnaire related to taste disturbance. However, Tomofuji et al. had only one patient out of 35 (2.9%) with taste disturbance along with elevated electrogustometry (EGM) threshold. Interestingly, one remained asymptomatic in spite of an elevated EGM.
Regarding gender distribution of taste disturbance, females were affected more than males (18.8% vs. 10.81%) although the difference was not statistically significant. Tessema et al. also found females more prone to taste disturbance, the reason being single-sized adult laryngoscope likely to cause trauma in a smaller oral cavity and pharynx of a female. Apart from this, females are considered to have more gustatory sensitivity than male.
Among these eight patients with taste disturbance, sucrose (8) was most affected tastant followed by salt (4) and citric acid (1). Three patients had taste disturbances for multiple tastants which consistently included sucrose. None of them had taste disturbance for caffeine. The taste sensation from anterior two-third of the tongue is carried by chorda tympani nerve via lingual nerve while the posterior region of the tongue is carried by lingual branch of glossopharyngeal nerve.,, Lingual nerve injury during MLS is likely to occur due to it being stretched during neck extension, tongue base pressure, or direct compression of the nerve by laryngoscope.,,, The nerve is most vulnerable just medial to the body of the mandible opposite third molar where it exits from medial pterygoid after running between medial and lateral pterygoids. Hence, the tastants in the anterior part of the tongue was affected while caffeine placed in the posterior part of the tongue was spared. In addition, the gustatory sensitivity for sucrose is higher as compared to other tastants as the number of stimulated fungiform papillae (fPap) are present in higher density at tongue tip. Hence, any injury to the lingual nerve results in reduction of fPap density at the tip of the tongue; so, alteration to sucrose tastant appears most common.
In this study, the patients with taste disturbance were found to have longer operative time than those who did not. Rosen et al. also noted higher rate of complications in those with longer operative duration which ranged from 5 to 142 min with mean being 52 min. Tessema et al. concluded the risk of complication increasing to three times if the operative time was between 30 and 60 min and five times if it exceeded an hour. This may be due to prolonged compression of the lingual nerve by the laryngoscope during the surgery leading to nerve hypoxia and injury. Interestingly, Landis et al. found no correlation between operation duration with taste disturbance although the operation duration ranged from 3 to 105 min with mean of 37 ± 4 min.
The taste disturbance in most cases was transient as evident by decrease in its frequency from 13.5% to 3.4% over the period of 3 weeks postoperatively in our study. Studies have cited complete regain of normal taste from a week to 3 months.,,,, The recovery could be due to resolution of neuropraxia of lingual nerve with time and also the turnover rate of taste buds at 10 days. Anastomosis between glossopharyngeal nerve and lingual nerve does raise the possibility of functional interactions between two. Since it is usually self-limiting, treatment is not needed. However, care while placing the laryngoscope and minimal tongue base pressure has been advocated in the first place to reduce the complication.
The study has several limitations. The solution for the chemogustometry method of taste assessment was prepared by the researchers, liable to human error during its preparation; hence, using commercially available taste strips would have been more standard. The MLS procedures were done by different surgeons which could have affected the operative time. A longer follow-up would have enabled assessment of the status of the two patients who still remained symptomatic even in 3-week follow-up.
| Conclusions|| |
Taste disturbance is a likely complication following MLS which is not given due importance in preoperative discussion with patient. Although transient and self-remitting, patient should be informed of the risk, more so for those requiring longer operative time.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]