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Assessment of eustachian tube function in tympanoplasty
Otolaryngology–Head and Neck Surgery (2009) 140, 889-893
ORIGINAL RESEARCH—OTOLOGY AND NEUROTOLOGY
Assessment of eustachian tube function in tympanoplasty Kishore Chandra Prasad, DLO, MS, Mahesh Chandra Hegde, MS, Sampath Chandra Prasad, MS, DNB, and Hari Meyappan, MS, Karnataka State, India No sponsorships or competing interests have been disclosed for this article. ABSTRACT OBJECTIVE: A clinically useful test for eustachian tube function (ETF) is still lacking. Here we plan to evaluate the mucociliary function of the ET by saccharin and methylene blue test, and compare the outcome of surgery with normal and abnormal ET functions. STUDY DESIGN: Case series with planned data collection. SETTING: Department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore (Manipal University), a tertiary care center in South India. SUBJECTS AND METHODS: This study comprised 86 patients diagnosed with mucosal chronic otitis media in quiescent/ inactive stage. All were subjected to a detailed clinical examination and investigations. Preoperative evaluation of ETF was compared with postoperative outcome of surgery, and the results were analyzed. RESULTS: The saccharin test and methylene blue dye test had a good correlation in evaluating ETF. The mean value for saccharin perception time and the clearance time for methylene blue were 17.5 and 8.1 minutes, respectively. ETF was best in anterior, worst among posterior, and intermediate in subtotal perforations. Type 1 tympanoplasty was successful in 94 percent with normal ETF and in 68 percent with partial dysfunction. CONCLUSION: The saccharin test is a simple, cost-effective, and valuable diagnostic tool to assess the mucociliary function of the ET. The outcome of middle ear surgery would be a success in normal ETF, whereas in partial dysfunction the outcome need not necessarily be a failure. © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
E
ustachian tube function (ETF) has been the center of focus as a prognostic factor because of its presumed primary role in the pathogenesis of otitis media and in clearance of the middle ear cavity.1 There is a general agreement that adequate ETF is necessary for successful middle ear surgery.2 Opinions have differed on the value of preoperative tubal function tests in chronic otitis media. Studies of eustachian tube patency have been studied by the Politzer, Valsalva, and Toynbee maneuvers. In other cases it
has been accomplished by testing air transport through the eustachian tube by tympanometry, sonotubometry, and air pressure equalization technique. However, these methods do not evaluate the drainage function, which may be impaired even though the tube is anatomically open.3 The saccharin test seems to provide adequate information of the mucociliary function and patency of the ET. The dye, because of its liquid form, gravitates through the ET to the nasopharynx rather than being actively transported. So the principal objective of the dye is to establish the anatomical presence or absence of tube patency. In this study we have attempted to evaluate the mucociliary function of the ET by the saccharin test and the anatomical patency of the tube by the methylene blue test, and to correlate the findings.
MATERIALS AND METHODS This case series with planned data collection was done at the department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore, a tertiary health center in coastal India. This study has been approved by the institutional review board. The study group comprised 86 patients who were diagnosed as having chronic otitis media (COM) of the tubotympanic type. The details of history with special emphasis on ear discharge, its duration, character, and period of dryness were noted. The inclusion criteria for the study were 1) patients diagnosed with mucosal type COM (tubotympanic type) presenting in the inactive or quiescent stage, 2) patients with no previous history of middle ear surgery on the test ear. The exclusion criteria were 1) patients diagnosed with mucosal type COM (tubotympanic type) presenting in the active stage, active squamous epithelial chronic otitis media (atticoantral type of COM, cholesteatoma), inactive squamous chronic otitis media (retraction pockets), any type of mastoiditis, otomycosis, and systemic diseases; 2) patients with cleft palate and history of possible trauma to the ET; 3) patients with recurrent allergic rhinitis.
Received September 22, 2008; revised January 19, 2009; accepted February 9, 2009.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2009.02.015
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Otolaryngology–Head and Neck Surgery, Vol 140, No 6, June 2009
A complete otolaryngological examination was performed to rule out any associated pathologies and focus of infection, which could influence the result of tympanoplasty. CT scan of the mastoids was done for all cases to rule out mastoiditis of any type. Audiological evaluation was done for all patients both preoperatively and postoperatively. Each patient was subjected to the following procedures.
Otoendoscopy With the use of an otoendoscope, the size and site of perforation were noted and tabulated. According to the site of the perforated quadrant, the perforation was classified into anterior, posterior, inferior, and subtotal. In a case of medium and large central perforation, the quadrant that was predominantly involved was taken into account. The condition of middle ear mucosa, annulus, handle of malleus, and remnant of tympanic membrane (TM) were also noted.
Diagnostic Nasal Endoscopy The patient’s nose was packed with 4 percent lignocaine solution for 10 minutes. Then with the use of 0- and 30degree sinoscopes, detailed nasal examination was carried out. The nasal findings and the condition of the ET orifice were noted.
Assessment of ETF Preoperatively the ETF was assessed in all patients by the following methods and their results were noted. Saccharin test. This procedure was used to determine the physiological patency of the ET. The procedure and its implications were explained to the patients. With the patient seated, under microscopic control, two Sweetex pellets were placed in the middle ear, at the ET opening, through the TM defect. The time required for the patient to taste the saccharin (ie, saccharin perception time [SPT]) was then measured. If the patient did not taste the saccharin after more
Figure 1
Methylene blue dye injected into middle ear.
Figure 2
Methylene blue dye in nasopharynx.
than 45 minutes, his or her taste sense was tested by directly placing the saccharin on the tongue. If this test was also negative, the result was noted as no response. The results of this test were classified into three groups as follows. The normal SPT was taken as less than 20 minutes, 20 to 45 minutes as partial dysfunction, and more than 45 minutes as gross dysfunction. Methylene blue dye test. This procedure was used to determine the anatomical patency of the ET. Two to three drops of sterile methylene blue dye were placed, with the use of an operating microscope, in the middle ear, at the ET opening, through the TM defect (Fig 1). With the use of a sinoscope, the nasopharyngeal end of the ET was focused to look for the dye (Fig 2) and the interval noted. The results of this test were classified into three groups as follows. The normal methylene blue clearance time was taken as less than 10 minutes, 10 to 20 minutes as partial dysfunction, and more than 20 minutes as gross dysfunction.
Surgical Procedure Within a week of evaluation of ETF, patients were operated on for type 1 tympanoplasty. In all cases, tympanoplasty was done under local anaesthesia through a post auricular approach by an underlay grafting technique using temporalis fascia as the graft material. Patients were reviewed after 3 weeks for inspection of the operated ear. The second and third postoperative reviews were done at 2 months and 6 months, respectively. Patients were evaluated postoperatively by otoscopy, tympanometry, and audiometry. However, hearing results were not used as an outcome measure. On the basis of middle ear status after type 1 tympanoplasty, patients were divided into three outcome groups: 1) successful outcome, defined as healed graft with good middle ear aeration; 2) retraction or atelectasis (healed graft with persistent high negative pressure); and 3) graft perforation during the follow-up period. The latter two outcomes were considered failures.
Prasad et al
Assessment of eustachian tube function in . . .
RESULTS Eighty-six consecutive patients were included in the study after fulfilling the study criteria. The age of the patients’ ranged from 15 to 59 years, and the majority were in the age group 20 to 40 years (68%), with a mean age of 31.32. Of the 86 patients, 45 were males and 41 were females, with no significant difference in sex ratio. With regard to perforations, 43 percent of the patients presented with subtotal perforation and 30 percent with large central perforation. In our series, 32 (37.21%) patients had anterior perforations, 17 (19.77%) had posterior perforations, and 37 (43.02%) had subtotal perforations. Preoperative audiology showed that 54 (63%) patients had conductive hearing loss between 15 to 25 dB, 29 (34%) had conductive hearing loss between 26 and 55 dB, and three (3%) had mixed hearing loss (⬍55 bB). Postoperatively, of the successful grafts, 79 percent of our patients had an air-bone gap of less than 20 dB, and the remaining 21 percent had a hearing loss between 20 and 35 dB. The mean value for SPT time was 17.583 minutes; methylene blue clearance time was 8.145 minutes. In the saccharin test, normal ETF was found in 64 patients (74.41%), partial dysfunction in 19 patients (22.09%), and gross dysfunction in three patients (3.48%). In the methylene blue dye test, normal ETF was found in 67 patients (77.90%), partial dysfunction in 16 patients (18.60%), and gross dysfunction in three patients (3.48%). The scatterplot in Figure 3 clearly shows that the regression line and correlation coefficient have a high correlation. The Rsq value of 0.6647 is closing in on the Pearson coefficient of 0.815 (Fig 3). This shows that the saccharin test and methylene blue dye test had a good correlation with each other in evaluating ETF. Hence, one can conclude that of the two tests, the saccharine test, being the less invasive test, can be performed on all patients being taken up for tympanoplasties.
Figure 3 Correlation between saccharin perception time (SPT) tests and methylene blue tests (MBT).
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Table 1 Success rate in relation to ETF Function of ET Normal Partial dysfunction Gross dysfunction
No. of patients Failures Success 64 19 03
04 06 03
93.75% 68.42% 0.00%
Success Rate in Relation to ETF As shown in Table 1, 60 patients (93.75%) with normal ETF and 13 patients (68.42%) with partial dysfunction had successful type 1 tympanoplasty. Those with gross dysfunctions had a 100 percent graft failure. The difference in success rate is statistically significant: 2 ⫽ 8.484, P ⫽ 0.014 SIG. Among the 13 failures, six involved medialization of graft and 7 involved perforation of graft.
Site of Perforation and ETF Posterior and subtotal perforations had a higher relationship with partial or gross ET dysfunction than anterior perforations. As shown in Table 2, the difference in positive mean time in relation to the site of perforation was found to be statistically significant: F ⫽ 6.875, P ⫽ 0.002 HS.
DISCUSSION A functioning ET is an integral part of a normal middle ear and thus is an essential requirement for optimum results in tympanoplastic operations. A preoperative test of tubal function is therefore of the greatest interest, especially if such a test provides a possibility of estimating the chances of achieving a satisfactory result of tympanoplasty.2 Earlier studies of ETF have mainly employed the technique of politzerization, which is insensitive and difficult to quantitate.4 Flisberg et al5 in 1963 worked out quantitative methods for measuring preoperative tubal function in patients with perforation of the eardrum. These methods have subsequently been used by a number of authors.4,6,7 They are based on the capability of the ET to equilibrate an induced negative or positive pressure in the middle ear by deglutition. However, these methods do not evaluate one of the most important functions of the ET, the drainage function, which may be impaired even though the tube is anatomically open.3 Sade8 in 1966 studied the middle ear mucosa systematically in autopsy material. He reported that clearance of the middle ear is an active process and is related to ciliary activity in the ear. The significance of ciliary activity is underlined by the fact that the ET leaves the tympanic cavity superiorly sloping downward in the direction of the nasopharynx. He demonstrated a physiological escalator in the middle ear comprising a mucus blanket carried by cilia. Foreign materials introduced into the middle ear are evacuated through the ET to the nasopharynx
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Otolaryngology–Head and Neck Surgery, Vol 140, No 6, June 2009
Table 2 Site of perforation and ETF Site of perforation Normal ET function Partial ET dysfunction Gross ET dysfunction Positive mean time (min) Anterior Posterior Subtotal
29 08 27
03 07 09
within minutes at a speed that corresponds with the known capability of cilia.9 The cilia are normally found embedded in a mucous layer over almost all the mucosa of the middle ear, on the inner layer of the TM, and in the ET. It is logical to assume that in disease states such as otitis media, the cilia play some part in evacuating the fluid that accumulates in the middle ear. In certain pathological conditions of the mucous membrane, especially when its secretory activity is increased, a decrease in the number of cilia-bearing cells occurs. Measurement of the time required for ciliary transport might therefore be used to estimate pathological changes in the mucous membrane.2 Sade9 in 1967 reported qualitative studies on the mucociliary function of the ET. He disclosed the mucous pathways from the middle ear cavity to the ET by using visible foreign charcoal particles, glass beads, and dried black ink. Since then, middle ear mucosa has been accepted as an active part of the upper respiratory mucosa. Several studies have evaluated ETF by using saccharin. The saccharin test seems to provide adequate information of the mucociliary function and patency of the ET. This test is considered a valuable supplement to other existing tests for tubal function.2 Gimenez et al10 studied the mucociliary function of the ET using 5 percent sodium saccharinate in 58 ears with dry central perforation of the TM. According to the SPT, they classified patients into three groups: group 1, normal function; time less than 20 minutes; group 2, partial dysfunction; time 20 to 90 minutes; group 3, gross dysfunction; time more than 90 minutes. Srivastav et al11 reported mucociliary function of the ET by mean of the saccharin test using a Sweetex tablet; they divided patients into two groups: 1) SPT ⬍ 45 minutes, which indicates a patent ET; 2) SPT ⬎ 45 minutes, which indicates a blocked ET. In our study we evaluated ETF by means of a similar technique using a Sweetex tablet, but we modified the classification by considering both studies. Less than 20 minutes was considered normal ETF, 20 to 45 minutes as partial dysfunction, and more than 45 minutes as gross dysfunction. The mean SPT in our study was in accordance with most of the authors.2,10,12 Elbrond et al2 used a saccharin crystal, which may be less soluble than the Sweetex pellets used in our study. This probably explains the disparity in timings although the same method was used. Dye studies to evaluate mucociliary function of ET in dry perforation were few in number. Rogers et al13 used fluorescent dye and found that dye injected in the middle ear can reach the nasopharynx in 10 minutes or less. Takahashi et al14 also reported normal
— 02 01
15 21.62 18.38
ET clearance to be within 10 minutes. In our study 78 percent of patients had clearance time of less than 10 minutes, which was taken as normal function. Elbrond et al2 suggested that the dye, owing to its liquid form, gravitates through the ET to the nasopharynx rather than being actively transported. So the principal objective of the dye is to establish the anatomical presence or absence of tube patency. The disadvantage of the dye test is that it requires an endoscope. Both tests described here also have the additional difficulty of keeping the patient in a given position during the tests. Although the dye tests establish the anatomical patency of the ET, the saccharine test establishes both the anatomical and physiological patency of the ET. The relationship between time of transport and type of perforation was studied by Gimenez et al.10 They found that the mucociliary function was best in ears with anterior perforations. The function was worst among posterior perforations and subtotal perforations showed intermediate results. Valles et al15 found contrasting results in their study. Their best results corresponded to posterior perforations, whereas worst cases were subtotal perforations. They observed no important differences between the sites of perforation. Our study results were very similar to those of Gimenez et al.10 The differences suggest the existence of a relationship between mucociliary transport and the site of perforation. The varying topography of the perforation would thus influence the integrity of the mucociliary system, or else the better or worse condition of the latter would influence the appearance of one type of perforation or another.10 When the ET is blocked anatomically or physiologically, it would not be wrong to assume that whatever is in the middle ear underneath the graft (ie, absorbable packing, effusion, etc) is not being cleared. Although one would expect negative pressure medialization and perforation of the graft if the ventilation function of the ET is deficient, it is not clear how the pent-up effusion or other blockage would increase the risk of graft failure, as opposed to the condition when the ET clears the middle ear. ETF is more complex than the test results reveal. Perhaps there are other functions or factors that are not ascertained by these tests. Although these tests assess the mucociliary transport mechanism, there may be factors related to the opening pressure or closure of the orifice or tube. Yet, the ETF tests are vital in the management of the middle ear with a TM perforation, especially because an entire new era of eustachian tuboplasty is rapidly developing with good re-
Prasad et al
Assessment of eustachian tube function in . . .
sults. House et al16 described eustachian tuboplasty in 1969. Since then very little was done in this field until the advent of laser and endoscopes. Since 2000, many articles have appeared describing various techniques of eustachian tuboplasty with good results. We have revisited hitherto ignored tests like the saccharine tests and the dye tests, which can provide vital information regarding ETFs. These tests are simple but fundamental and need to be incorporated into the preoperative investigative repertoire of every otologist. Previously established time values for normal and abnormal clearances of saccharine and dyes placed in the middle ear were confirmed by our study. We also made an attempt to correlate the state of the mucociliary transport system with the results of reconstructive surgery of the middle ear. Consistent with other studies, good ETF was shown to predict good outcome. We were not able to comment on the relation between tubal function and tympanoplasty in a gross dysfunction group because we had only three patients in this category; however, other studies have shown poor results for tympanoplasty in this group. This population would be the best to study for the benefits of tuboplasty.
CONCLUSION ETF tests must be a part of the investigative repertoire in managing a TM perforation. These tests are important in that they may have good predictive value, and are useful at a time when a new field of endoscopic eustachian tuboplasty is just beginning for tubal dysfunction and patency. The saccharin test is an easy, simple, and cost-effective method because it does not require any sophisticated equipment. It promises to be a useful diagnostic tool to assess the mucociliary function of the ET as well as its anatomical patency. We regard it as a valuable supplement to other existing tests for tubal function. The existence of good tubotympanic mucociliary drainage constitutes a favorable prognostic factor in the outcome of reconstructive surgery in the middle ear. We infer that middle ear surgery resulting in normal ETF would be a successful outcome, although partial dysfunction need not necessarily be a failure.
AUTHOR INFORMATION From the Department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore, Manipal University.
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Corresponding author: Kishore Chandra Prasad, DLO, MS, First Floor, Nethravathi Building, Balmatta, Mangalore - 575001, South Kanara, Karnataka State, India. E-mail address: [email protected].
AUTHOR CONTRIBUTIONS Kishore Chandra Prasad, chief surgeon, principal investigator; Mahesh Chandra Hegde, second investigator, referred cases; Sampath Chandra Prasad, researched references, participated in ETF tests for all patients; Hari Meyappan, researched references, participated in ETF tests for all patients.
DISCLOSURES Competing interests: None. Sponsorships: None.
REFERENCES 1. Manning SC, Cantekin EI, Kenna MA, et al. Prognostic value of eustachian tube functions in paediatric tympanoplasty. Laryngoscope 1987;97:1012– 6. 2. Elbrond O, Larsen E. Mucociliary functions of the eustachian tube. Arch Otolaryngol 1976;102:539 – 41. 3. Nuutinen J, Karja J, Karjalainen P. Measurement of mucociliary function of the eustachian tube. Arch Otolaryngol 1983;109:669 –72. 4. Miller GF. Eustachian tubal function in normal and diseased ears. Arch Otolaryngol 1965;81:41– 8. 5. Flisberg K. Ventilatory studies on the eustachian tube. Acta Otolaryngologica 1966;219:1– 82. 6. Bortnick E. A simple apparatus to measure eustachian tubal function. Arch Otolaryngol 1966;83:38. 7. Andreasson L, Harris S. Tympanoplasty and eustachian tube function. Clin Otolaryngol Allied Sci 1978;3:421–30. 8. Sade J. Middle ear mucosa. Arch Otolaryngol 1966;84:41–7. 9. Sade J. Ciliary activity and middle ear clearance. Arch Otolaryngol 1967;86:22–9. 10. Gimenez F, Algarra M. The prognostic value of mucociliary clearance in predicting success in tympanoplasty. J Laryngol Otol 1993;107: 895–7. 11. Srivastav SC, Gupta SC, Singh AP. Efficacy of various methods in evaluation of eustachian tube function. Indian J Otolaryngol Head Neck Surg 1993;2:188 –90. 12. Jesic S, Nesic V. Mucociliary transport in eustachian tubes in chronic suppurative otitis media. Srp Arh Celok Lek 2004;132:148 –51. 13. Rogers LR, Kirchner FR, Proud GO. The evaluation of eustachian tubal function by fluorescent studies. Laryngoscope 1962;72:456 – 67. 14. Takahashi H, Hayashi M, Sato H, et al. Primary deficits in Eustachian tube function in patients with otitis media with effusion. Arch Otolaryngol Head Neck Surg 1989;115:581– 4. 15. Valles H, Banzo J, Ferrer JJ. Aportaciones al studio de la function de drenage de la trompa de eustaquio mediante escintigrafia secuncial. Annales Otorrinolaringologicos Iberoamericanos 1981;8:399 – 415. 16. House WF, Glasscock ME 3rd, Miles J. Eustachian tuboplasty. Laryngoscope 1969;79:1765– 82.
ORIGINAL RESEARCH—OTOLOGY AND NEUROTOLOGY
Assessment of eustachian tube function in tympanoplasty Kishore Chandra Prasad, DLO, MS, Mahesh Chandra Hegde, MS, Sampath Chandra Prasad, MS, DNB, and Hari Meyappan, MS, Karnataka State, India No sponsorships or competing interests have been disclosed for this article. ABSTRACT OBJECTIVE: A clinically useful test for eustachian tube function (ETF) is still lacking. Here we plan to evaluate the mucociliary function of the ET by saccharin and methylene blue test, and compare the outcome of surgery with normal and abnormal ET functions. STUDY DESIGN: Case series with planned data collection. SETTING: Department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore (Manipal University), a tertiary care center in South India. SUBJECTS AND METHODS: This study comprised 86 patients diagnosed with mucosal chronic otitis media in quiescent/ inactive stage. All were subjected to a detailed clinical examination and investigations. Preoperative evaluation of ETF was compared with postoperative outcome of surgery, and the results were analyzed. RESULTS: The saccharin test and methylene blue dye test had a good correlation in evaluating ETF. The mean value for saccharin perception time and the clearance time for methylene blue were 17.5 and 8.1 minutes, respectively. ETF was best in anterior, worst among posterior, and intermediate in subtotal perforations. Type 1 tympanoplasty was successful in 94 percent with normal ETF and in 68 percent with partial dysfunction. CONCLUSION: The saccharin test is a simple, cost-effective, and valuable diagnostic tool to assess the mucociliary function of the ET. The outcome of middle ear surgery would be a success in normal ETF, whereas in partial dysfunction the outcome need not necessarily be a failure. © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
E
ustachian tube function (ETF) has been the center of focus as a prognostic factor because of its presumed primary role in the pathogenesis of otitis media and in clearance of the middle ear cavity.1 There is a general agreement that adequate ETF is necessary for successful middle ear surgery.2 Opinions have differed on the value of preoperative tubal function tests in chronic otitis media. Studies of eustachian tube patency have been studied by the Politzer, Valsalva, and Toynbee maneuvers. In other cases it
has been accomplished by testing air transport through the eustachian tube by tympanometry, sonotubometry, and air pressure equalization technique. However, these methods do not evaluate the drainage function, which may be impaired even though the tube is anatomically open.3 The saccharin test seems to provide adequate information of the mucociliary function and patency of the ET. The dye, because of its liquid form, gravitates through the ET to the nasopharynx rather than being actively transported. So the principal objective of the dye is to establish the anatomical presence or absence of tube patency. In this study we have attempted to evaluate the mucociliary function of the ET by the saccharin test and the anatomical patency of the tube by the methylene blue test, and to correlate the findings.
MATERIALS AND METHODS This case series with planned data collection was done at the department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore, a tertiary health center in coastal India. This study has been approved by the institutional review board. The study group comprised 86 patients who were diagnosed as having chronic otitis media (COM) of the tubotympanic type. The details of history with special emphasis on ear discharge, its duration, character, and period of dryness were noted. The inclusion criteria for the study were 1) patients diagnosed with mucosal type COM (tubotympanic type) presenting in the inactive or quiescent stage, 2) patients with no previous history of middle ear surgery on the test ear. The exclusion criteria were 1) patients diagnosed with mucosal type COM (tubotympanic type) presenting in the active stage, active squamous epithelial chronic otitis media (atticoantral type of COM, cholesteatoma), inactive squamous chronic otitis media (retraction pockets), any type of mastoiditis, otomycosis, and systemic diseases; 2) patients with cleft palate and history of possible trauma to the ET; 3) patients with recurrent allergic rhinitis.
Received September 22, 2008; revised January 19, 2009; accepted February 9, 2009.
0194-5998/$36.00 © 2009 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2009.02.015
890
Otolaryngology–Head and Neck Surgery, Vol 140, No 6, June 2009
A complete otolaryngological examination was performed to rule out any associated pathologies and focus of infection, which could influence the result of tympanoplasty. CT scan of the mastoids was done for all cases to rule out mastoiditis of any type. Audiological evaluation was done for all patients both preoperatively and postoperatively. Each patient was subjected to the following procedures.
Otoendoscopy With the use of an otoendoscope, the size and site of perforation were noted and tabulated. According to the site of the perforated quadrant, the perforation was classified into anterior, posterior, inferior, and subtotal. In a case of medium and large central perforation, the quadrant that was predominantly involved was taken into account. The condition of middle ear mucosa, annulus, handle of malleus, and remnant of tympanic membrane (TM) were also noted.
Diagnostic Nasal Endoscopy The patient’s nose was packed with 4 percent lignocaine solution for 10 minutes. Then with the use of 0- and 30degree sinoscopes, detailed nasal examination was carried out. The nasal findings and the condition of the ET orifice were noted.
Assessment of ETF Preoperatively the ETF was assessed in all patients by the following methods and their results were noted. Saccharin test. This procedure was used to determine the physiological patency of the ET. The procedure and its implications were explained to the patients. With the patient seated, under microscopic control, two Sweetex pellets were placed in the middle ear, at the ET opening, through the TM defect. The time required for the patient to taste the saccharin (ie, saccharin perception time [SPT]) was then measured. If the patient did not taste the saccharin after more
Figure 1
Methylene blue dye injected into middle ear.
Figure 2
Methylene blue dye in nasopharynx.
than 45 minutes, his or her taste sense was tested by directly placing the saccharin on the tongue. If this test was also negative, the result was noted as no response. The results of this test were classified into three groups as follows. The normal SPT was taken as less than 20 minutes, 20 to 45 minutes as partial dysfunction, and more than 45 minutes as gross dysfunction. Methylene blue dye test. This procedure was used to determine the anatomical patency of the ET. Two to three drops of sterile methylene blue dye were placed, with the use of an operating microscope, in the middle ear, at the ET opening, through the TM defect (Fig 1). With the use of a sinoscope, the nasopharyngeal end of the ET was focused to look for the dye (Fig 2) and the interval noted. The results of this test were classified into three groups as follows. The normal methylene blue clearance time was taken as less than 10 minutes, 10 to 20 minutes as partial dysfunction, and more than 20 minutes as gross dysfunction.
Surgical Procedure Within a week of evaluation of ETF, patients were operated on for type 1 tympanoplasty. In all cases, tympanoplasty was done under local anaesthesia through a post auricular approach by an underlay grafting technique using temporalis fascia as the graft material. Patients were reviewed after 3 weeks for inspection of the operated ear. The second and third postoperative reviews were done at 2 months and 6 months, respectively. Patients were evaluated postoperatively by otoscopy, tympanometry, and audiometry. However, hearing results were not used as an outcome measure. On the basis of middle ear status after type 1 tympanoplasty, patients were divided into three outcome groups: 1) successful outcome, defined as healed graft with good middle ear aeration; 2) retraction or atelectasis (healed graft with persistent high negative pressure); and 3) graft perforation during the follow-up period. The latter two outcomes were considered failures.
Prasad et al
Assessment of eustachian tube function in . . .
RESULTS Eighty-six consecutive patients were included in the study after fulfilling the study criteria. The age of the patients’ ranged from 15 to 59 years, and the majority were in the age group 20 to 40 years (68%), with a mean age of 31.32. Of the 86 patients, 45 were males and 41 were females, with no significant difference in sex ratio. With regard to perforations, 43 percent of the patients presented with subtotal perforation and 30 percent with large central perforation. In our series, 32 (37.21%) patients had anterior perforations, 17 (19.77%) had posterior perforations, and 37 (43.02%) had subtotal perforations. Preoperative audiology showed that 54 (63%) patients had conductive hearing loss between 15 to 25 dB, 29 (34%) had conductive hearing loss between 26 and 55 dB, and three (3%) had mixed hearing loss (⬍55 bB). Postoperatively, of the successful grafts, 79 percent of our patients had an air-bone gap of less than 20 dB, and the remaining 21 percent had a hearing loss between 20 and 35 dB. The mean value for SPT time was 17.583 minutes; methylene blue clearance time was 8.145 minutes. In the saccharin test, normal ETF was found in 64 patients (74.41%), partial dysfunction in 19 patients (22.09%), and gross dysfunction in three patients (3.48%). In the methylene blue dye test, normal ETF was found in 67 patients (77.90%), partial dysfunction in 16 patients (18.60%), and gross dysfunction in three patients (3.48%). The scatterplot in Figure 3 clearly shows that the regression line and correlation coefficient have a high correlation. The Rsq value of 0.6647 is closing in on the Pearson coefficient of 0.815 (Fig 3). This shows that the saccharin test and methylene blue dye test had a good correlation with each other in evaluating ETF. Hence, one can conclude that of the two tests, the saccharine test, being the less invasive test, can be performed on all patients being taken up for tympanoplasties.
Figure 3 Correlation between saccharin perception time (SPT) tests and methylene blue tests (MBT).
891
Table 1 Success rate in relation to ETF Function of ET Normal Partial dysfunction Gross dysfunction
No. of patients Failures Success 64 19 03
04 06 03
93.75% 68.42% 0.00%
Success Rate in Relation to ETF As shown in Table 1, 60 patients (93.75%) with normal ETF and 13 patients (68.42%) with partial dysfunction had successful type 1 tympanoplasty. Those with gross dysfunctions had a 100 percent graft failure. The difference in success rate is statistically significant: 2 ⫽ 8.484, P ⫽ 0.014 SIG. Among the 13 failures, six involved medialization of graft and 7 involved perforation of graft.
Site of Perforation and ETF Posterior and subtotal perforations had a higher relationship with partial or gross ET dysfunction than anterior perforations. As shown in Table 2, the difference in positive mean time in relation to the site of perforation was found to be statistically significant: F ⫽ 6.875, P ⫽ 0.002 HS.
DISCUSSION A functioning ET is an integral part of a normal middle ear and thus is an essential requirement for optimum results in tympanoplastic operations. A preoperative test of tubal function is therefore of the greatest interest, especially if such a test provides a possibility of estimating the chances of achieving a satisfactory result of tympanoplasty.2 Earlier studies of ETF have mainly employed the technique of politzerization, which is insensitive and difficult to quantitate.4 Flisberg et al5 in 1963 worked out quantitative methods for measuring preoperative tubal function in patients with perforation of the eardrum. These methods have subsequently been used by a number of authors.4,6,7 They are based on the capability of the ET to equilibrate an induced negative or positive pressure in the middle ear by deglutition. However, these methods do not evaluate one of the most important functions of the ET, the drainage function, which may be impaired even though the tube is anatomically open.3 Sade8 in 1966 studied the middle ear mucosa systematically in autopsy material. He reported that clearance of the middle ear is an active process and is related to ciliary activity in the ear. The significance of ciliary activity is underlined by the fact that the ET leaves the tympanic cavity superiorly sloping downward in the direction of the nasopharynx. He demonstrated a physiological escalator in the middle ear comprising a mucus blanket carried by cilia. Foreign materials introduced into the middle ear are evacuated through the ET to the nasopharynx
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Table 2 Site of perforation and ETF Site of perforation Normal ET function Partial ET dysfunction Gross ET dysfunction Positive mean time (min) Anterior Posterior Subtotal
29 08 27
03 07 09
within minutes at a speed that corresponds with the known capability of cilia.9 The cilia are normally found embedded in a mucous layer over almost all the mucosa of the middle ear, on the inner layer of the TM, and in the ET. It is logical to assume that in disease states such as otitis media, the cilia play some part in evacuating the fluid that accumulates in the middle ear. In certain pathological conditions of the mucous membrane, especially when its secretory activity is increased, a decrease in the number of cilia-bearing cells occurs. Measurement of the time required for ciliary transport might therefore be used to estimate pathological changes in the mucous membrane.2 Sade9 in 1967 reported qualitative studies on the mucociliary function of the ET. He disclosed the mucous pathways from the middle ear cavity to the ET by using visible foreign charcoal particles, glass beads, and dried black ink. Since then, middle ear mucosa has been accepted as an active part of the upper respiratory mucosa. Several studies have evaluated ETF by using saccharin. The saccharin test seems to provide adequate information of the mucociliary function and patency of the ET. This test is considered a valuable supplement to other existing tests for tubal function.2 Gimenez et al10 studied the mucociliary function of the ET using 5 percent sodium saccharinate in 58 ears with dry central perforation of the TM. According to the SPT, they classified patients into three groups: group 1, normal function; time less than 20 minutes; group 2, partial dysfunction; time 20 to 90 minutes; group 3, gross dysfunction; time more than 90 minutes. Srivastav et al11 reported mucociliary function of the ET by mean of the saccharin test using a Sweetex tablet; they divided patients into two groups: 1) SPT ⬍ 45 minutes, which indicates a patent ET; 2) SPT ⬎ 45 minutes, which indicates a blocked ET. In our study we evaluated ETF by means of a similar technique using a Sweetex tablet, but we modified the classification by considering both studies. Less than 20 minutes was considered normal ETF, 20 to 45 minutes as partial dysfunction, and more than 45 minutes as gross dysfunction. The mean SPT in our study was in accordance with most of the authors.2,10,12 Elbrond et al2 used a saccharin crystal, which may be less soluble than the Sweetex pellets used in our study. This probably explains the disparity in timings although the same method was used. Dye studies to evaluate mucociliary function of ET in dry perforation were few in number. Rogers et al13 used fluorescent dye and found that dye injected in the middle ear can reach the nasopharynx in 10 minutes or less. Takahashi et al14 also reported normal
— 02 01
15 21.62 18.38
ET clearance to be within 10 minutes. In our study 78 percent of patients had clearance time of less than 10 minutes, which was taken as normal function. Elbrond et al2 suggested that the dye, owing to its liquid form, gravitates through the ET to the nasopharynx rather than being actively transported. So the principal objective of the dye is to establish the anatomical presence or absence of tube patency. The disadvantage of the dye test is that it requires an endoscope. Both tests described here also have the additional difficulty of keeping the patient in a given position during the tests. Although the dye tests establish the anatomical patency of the ET, the saccharine test establishes both the anatomical and physiological patency of the ET. The relationship between time of transport and type of perforation was studied by Gimenez et al.10 They found that the mucociliary function was best in ears with anterior perforations. The function was worst among posterior perforations and subtotal perforations showed intermediate results. Valles et al15 found contrasting results in their study. Their best results corresponded to posterior perforations, whereas worst cases were subtotal perforations. They observed no important differences between the sites of perforation. Our study results were very similar to those of Gimenez et al.10 The differences suggest the existence of a relationship between mucociliary transport and the site of perforation. The varying topography of the perforation would thus influence the integrity of the mucociliary system, or else the better or worse condition of the latter would influence the appearance of one type of perforation or another.10 When the ET is blocked anatomically or physiologically, it would not be wrong to assume that whatever is in the middle ear underneath the graft (ie, absorbable packing, effusion, etc) is not being cleared. Although one would expect negative pressure medialization and perforation of the graft if the ventilation function of the ET is deficient, it is not clear how the pent-up effusion or other blockage would increase the risk of graft failure, as opposed to the condition when the ET clears the middle ear. ETF is more complex than the test results reveal. Perhaps there are other functions or factors that are not ascertained by these tests. Although these tests assess the mucociliary transport mechanism, there may be factors related to the opening pressure or closure of the orifice or tube. Yet, the ETF tests are vital in the management of the middle ear with a TM perforation, especially because an entire new era of eustachian tuboplasty is rapidly developing with good re-
Prasad et al
Assessment of eustachian tube function in . . .
sults. House et al16 described eustachian tuboplasty in 1969. Since then very little was done in this field until the advent of laser and endoscopes. Since 2000, many articles have appeared describing various techniques of eustachian tuboplasty with good results. We have revisited hitherto ignored tests like the saccharine tests and the dye tests, which can provide vital information regarding ETFs. These tests are simple but fundamental and need to be incorporated into the preoperative investigative repertoire of every otologist. Previously established time values for normal and abnormal clearances of saccharine and dyes placed in the middle ear were confirmed by our study. We also made an attempt to correlate the state of the mucociliary transport system with the results of reconstructive surgery of the middle ear. Consistent with other studies, good ETF was shown to predict good outcome. We were not able to comment on the relation between tubal function and tympanoplasty in a gross dysfunction group because we had only three patients in this category; however, other studies have shown poor results for tympanoplasty in this group. This population would be the best to study for the benefits of tuboplasty.
CONCLUSION ETF tests must be a part of the investigative repertoire in managing a TM perforation. These tests are important in that they may have good predictive value, and are useful at a time when a new field of endoscopic eustachian tuboplasty is just beginning for tubal dysfunction and patency. The saccharin test is an easy, simple, and cost-effective method because it does not require any sophisticated equipment. It promises to be a useful diagnostic tool to assess the mucociliary function of the ET as well as its anatomical patency. We regard it as a valuable supplement to other existing tests for tubal function. The existence of good tubotympanic mucociliary drainage constitutes a favorable prognostic factor in the outcome of reconstructive surgery in the middle ear. We infer that middle ear surgery resulting in normal ETF would be a successful outcome, although partial dysfunction need not necessarily be a failure.
AUTHOR INFORMATION From the Department of Otolaryngology–Head and Neck Surgery, Kasturba Medical College, Mangalore, Manipal University.
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Corresponding author: Kishore Chandra Prasad, DLO, MS, First Floor, Nethravathi Building, Balmatta, Mangalore - 575001, South Kanara, Karnataka State, India. E-mail address: [email protected].
AUTHOR CONTRIBUTIONS Kishore Chandra Prasad, chief surgeon, principal investigator; Mahesh Chandra Hegde, second investigator, referred cases; Sampath Chandra Prasad, researched references, participated in ETF tests for all patients; Hari Meyappan, researched references, participated in ETF tests for all patients.
DISCLOSURES Competing interests: None. Sponsorships: None.
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