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 Table of Contents  
ORIGINAL ARTICLE
Year : 2013  |  Volume : 19  |  Issue : 3  |  Page : 111-113

Short term and long term subjective taste disorder after middle ear cleft surgery


1 Department of Otolaryngology, Sher-i-Kashmir Institute of Medical Sciences Medical College, Bemina, Srinagar, Jammu and Kashmir, India
2 Department of Anatomy, Sher-i-Kashmir Institute of Medical Sciences Medical College, Bemina, Srinagar, Jammu and Kashmir, India
3 Department of Otorhinolaryngology in Government Medical College, Srinagar, Jammu and Kashmir, India

Date of Web Publication2-Sep-2013

Correspondence Address:
Ayaz Rehman
Department of Otorhinolaryngology, Sher-i-Kashmir Institute of Medical Sciences Medical College, Bemina, Srinagar, Jammu and Kashmir
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-7749.117473

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  Abstract 

Aim: The present study is a prospective study that looks into the prevalence of chorda tympani nerve injury and related symptoms following varying degrees of trauma to the nerve during four common types of middle-ear operations; namely, Tympanomastoid operations, myringoplasty, Tympanoplasty and Exploratory tympanotomy. Materials and Methods: 178 patients who underwent middle ear cleft surgery were included in this prospective study. Childrens below 20 years and patients with other potential cause of taste disturbance were excluded. Patients were given a single questionnaire, so as to assess their post-operative taste disturbance. Patient name, Age, Sex, Type of middle ear surgery, side of surgery were recorded. Any change in sense of taste immediately (after 2-4 weeks) or delayed (2-3 years)were recorded. Results: The number of patients with Chorda tympani nerve-related symptoms varied widely between these four groups. Increased occurrence of the nerve related symptoms were observed in Tympanomastoid and Myringoplasty, and a prolonged recovery time were observed in the tympanomastoid group. Stretching of the nerve produced more symptomatic cases than thermal injury or drying. Conclusion: It is important to inform patients about the possibility of Chorda Tympani Nerve injury during middle-ear operations, and it should also be emphasized that symptoms related to Chorda Tympani Nerve injury can occur irrespective of the type of damage to the nerve.

Keywords: Chorda tympani nerve, Ear, Middle ear cleft operations


How to cite this article:
Rehman A, Hamid S, Sangoo M, Kirmani M, Wani A, Chisti LA. Short term and long term subjective taste disorder after middle ear cleft surgery. Indian J Otol 2013;19:111-3

How to cite this URL:
Rehman A, Hamid S, Sangoo M, Kirmani M, Wani A, Chisti LA. Short term and long term subjective taste disorder after middle ear cleft surgery. Indian J Otol [serial online] 2013 [cited 2019 Jul 17];19:111-3. Available from: http://www.indianjotol.org/text.asp?2013/19/3/111/117473


  Introduction Top


The site for taste perception has been identified as the taste buds located in the area of the tongue, soft palate, oropharyngeal mucosa, and also the epiglottis. Humans perceive taste through sensory organs called taste buds,or gustatory calyculi, concentrated on the top of thetongue. The taste buds, approx. 4,600 on average, consist of 20 to 50 cells arranged like slices of an orange, exposing the taste pore in the center. The microvilli of neuroepithelial sensory cells extend into the taste pore [1] The life-span of taste buds ranges from about 10 to 20 days. [2] The majority of taste buds are located on taste papillae classified as vallate papillae, filiform papillae, and fungiform papillae [3],[4] . Basically, each type of papilla is sensitive to several, if not all, taste modalities. [5] Innervation takes place via the chorda tympani nerve, glossopharyngeal nerve, and vagus nerve. Excitatory transmission for acidic and salty tastes occurs directly via ions, whereas sweet and bitter tastes trigger secondarymessenger systems via membrane-specific receptors. [6],[7]

Iatrogenic damage to the chorda tympani nerve is a well-recognised complication of middle-ear cleft surgery. The overall reported prevalence of related symptoms after surgery of middle ears is between 15 and 22%, although chorda tympani nerve injury occurs more often.The consequences of injury were variable, prognosis is difficult to predict and prevention is sometimes controversial.

The lengthy course of chorda tympan inerve exposes it to the risk of injury in a variety of surgical procedure, most commonly, during middle ear surgery. Frequency of cases is difficult to determine and depends on; the surgical procedure,the technique underlying pathology and methods,andthe timing of detection. The chorda tympani nerve may be injured by a variety of mechanisms including transection, stretching, ischaemia, thermal injury, excessive handling and desiccation. Nerve transection maybe accidental or deliberate. Stretching is a common mechanism, such as, when raising a tympanomeatal flap during myringoplasty. Various authors have reported thermal injury from bone drilling or diathermy and drying from the microscopic heat or from prolonged exposure without moistening.

The classic feature of chorda tympani nerve injury are loss or alteration of taste with or withoutdryness of mouth, both of which are related to the main functions of the nerve.

In our experience, taste disturbance is rarely discussed with patients when obtaining consent for middle ear cleft surgery. This study aimed to determine whether or not taste disturbance is significant consequence that warrants greater consideration during the middle ear cleft consent procedure.


  Questionairre Top


  • Any change in your sense of taste {immediately (after 2-4 weeks) or delayed (2-3 years)} (YES/NO)
  • If yes, was it
    1. reduced
    2. loss of taste
    3. altered taste

  Materials and Methods Top


This prospective study was conducted in a tertiary care hospital from 2008 to 2012; and 178 patients who underwent middle ear cleft surgery were included.Childrens below 20 years and patients with other potential cause of taste disturbance were excluded. Patients were given a single questionnaire, so as to assess their post-operative taste disturbance. Patient name, Age, Sex, Type of middle ear surgery, side of surgery were recorded.


  Results Top


In our study of 178 cases, the malescomprise 98 cases (55.06%) whereas the females constitute 80 cases (44.94%)[Table 1]. The age groups of these cases selected were between20-65 years [Table 2]. The four surgeries of middle ear cleft taken into consideration were Tympanomastoid surgery, Myringoplasty, Tympanoplastyand Exploratory tympanotomy. Majority of the cases were contributed by those cases who underwent myringoplasty (111 cases, 62.35%) and least number of cases were from those who underwent Tympanoplasty (11 cases, 6.17%) [Table 3]. Thirty-two (17.97%) patients reported taste disturbance. Altered taste was most reported (n = 21, 65.62%) with loss of taste reported by 3.12% (n = 1),whereas decreased taste was seen in 10 cases (31.25%) [Table 4]. Symptoms were most observed in the tympanomastoid group (43.75%). [Table 5]. Recovery was complete in 75% (n = 24) of the symptomatic cases by 12 months [Table 6].
Table 1: Shows sex incidence of the cases

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Table 2: Shows most common age-group studied

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Table 3: Shows post-operative taste changes in various middle ear surgeries

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Table 4: Change in sense of taste in different middle-ear surgeries

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Table 5: Percentage of chorda tympani nerve damage due to different middle ear surgeries

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Table 6: The table shows the percentage of affected cases who recovered

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  Discussion Top


The incidence of olfactory disorders is appoximately 1-2% and they can seriously impact on the quality of life. Olfactory disorders are classified according to the etiology and therapy is planned according to the underlying pathophysiology. In ENT patients olfactory disorders caused by sinonasal diseases are the most common ones, followed by postviral disorders. Isolated taste disorders are rare and in most often caused by underlying diseases or side effects of medications. Taste disorders after tonsillectomy caused by pressure on the lingual branch of the glossopharyngeal nerve are rare (0.31%) and generally disappear spontaneously [8] . Just et al., [9] studied 118 patients with a strained or severed chorda tympani nerve after various surgeries. The subjective complaints in these patients were highly variable and did not necessarily correlate with measured taste perception. Saito et al., [10] also demonstrated better long-term recovery of clinical (subjective) taste perception than of objective taste function measured by electrogustometry. After 2 years, barely 2.7% of the patients (n = 113) reported subjective taste impairment. This low rate was thought to be caused by the loss of central inhibition. [11]. In patients with lingual nerve injuries excision of neurinomas and end-to-end suture resulted in improved postoperative taste perception in 40% of cases. [12] Clark et al., [13] Gopalan P [14] and Michael P [15] also observed a significantly higher incidence of taste disturbance following myringoplasty and stapedectomy compared to procedures in which the initial diagnosis was cholesteatoma, regardless of the extent of injury sustained by the nerve. The most common complaint after chorda tympani nerve injury is of a metallic taste sensation.


  Conclusion Top


Patients who undergo middle ear surgery should be thoroughly counseled with respect to Chorda tympanic nerve injury and symptoms regardless of the type of damage to the nerve.


  Significance Top


This study highlights the high incidence of postoperative alterations in taste after middle ear surgery, especially in non-diseased ears, and that Chorda tympani nerve transection results in fewer symptoms than Chorda tympani nerve stretching.

 
  References Top

1.Miller IJ, Bartoshuk LM. Taste perception, taste bud distribution, and spatial relationships In: Getchell ML, Bartoshuk LM, Doty RL, Snow JB, editors. Smell and taste in health and disease. New York: Raven Press; 1991. p. 205-33.  Back to cited text no. 1
    
2.Beidler LM, Smallman RL. Renewal of cells within taste buds. J Cell Biol 1965;27:263-72.  Back to cited text no. 2
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3.Miller IJ, Reedy FEJr. Variations in human taste bud density and taste intensity perception. PhysiolBehav 1990;47:1213-19.   Back to cited text no. 3
    
4.Cullen MM, Leopold DA. Disorders of smell and taste. Med Clin North Am1999;83:57-74.  Back to cited text no. 4
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5.Smith DV. Basic anatomy and physiology of taste. In: Seiden AM, editor. Taste and smell disorders. New York: Thieme; 1997. p. 128-45.  Back to cited text no. 5
    
6.Kinnamon SC. Taste transduction: A diversity of mechanisms. Trends Neurosci 1988;11:491-6.  Back to cited text no. 6
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7.Kinnamon SC, Margolskee RF. Mechanisms of taste transduction. Curr Opin Neurobiol1996;6:506-13.   Back to cited text no. 7
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8.Tomita H, Ohtuka K. Taste disturbance after tonsillectomy. Acta Otolaryngol Suppl 2002;S546:164-72.  Back to cited text no. 8
    
9.Just T, Homoth J, Graumüller S, Pau HW. Taste disorders and recovery of the taste function after middle ear surgery. Larygohinootologie 2002;82:494-500.  Back to cited text no. 9
    
10.Saito T, Manabe Y, Shibamori Y, Yamagishi T, Igawa H, Tokuriki M, et al. Long-term follow-up results of electrogustometry and subjective taste disorder after middle ear surgery. Laryngoscope 2001;111:2064-70.  Back to cited text no. 10
    
11.Lehman CD, Bartoshuk LM, Catalanotto FC, Kveton JF, Lowlicht RA. Effect of anesthesia of the chorda tympani nerve on taste perception in humans. Physiol Behav 1995;57:943-51.   Back to cited text no. 11
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12.Robinson PP, Loescher AR, Smith KG. A prospective, quantitative study on the clinical outcome of lingual nerve repair. Br J Oral Maxillofac Surg 2002;38:255-63.   Back to cited text no. 12
    
13.Clark MP, O'Malley S. Chorda tympani nerve function after middle ear surgery. Otol Neurotol 2007;28:335-40.  Back to cited text no. 13
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14.Gopalan P, Kumar M, Gupta D, Phillips JJ. A study ofchorda tympani nerve injury and related symptoms following middle ear surgery. J Laryngol Otol 2005;119:189-92.  Back to cited text no. 14
    
15.Michael P, Raut V. Chorda tympani injury: Operative findings and postoperative symptoms.Otolaryngol Head Neck Surg 2007;136:978-81.  Back to cited text no. 15
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


This article has been cited by
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The Laryngoscope. 2017;
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  In this article
Abstract
Introduction
Questionairre
Materials and Me...
Results
Discussion
Conclusion
Significance
References
Article Tables

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