|Year : 2011 | Volume
| Issue : 3 | Page : 113-116
A simplified approach to assess variations in Eustachian tubal ventilatory function by Bortnick-Miller apparatus in chronic otitis media cases (dry) before surgery
Apoorva Kumar Pandey, SC Gupta, M Singh
Department of ENT and Head-Neck Surgery, M.L.N. Medical College, Allahabad, Uttar Pradesh, India
|Date of Web Publication||26-Dec-2011|
Apoorva Kumar Pandey
Department of ENT and Head-Neck Surgery, SGRR IM and Health Sciences, Dehradun, Uttarakhand
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study is to see the different functional gradings of Eustachian tube ventilatory function as assessed by Bortnick-Miller (B-M) apparatus in chronically diseased middle ears (dry cases) planned to undergo tympanoplasty and to correlate the results with the past experiences. Materials and Methods: This study consisted of 29 cases of chronic suppurative otitis media, inactive stage having central perforation. Tubal function was evaluated by B-M apparatus based on ability of tube assimilating the applied positive and negative pressure. Tubal opening pressure was noted after applying positive pressure while residual intratympanic pressure after 10 swallows was recorded after applying negative pressure. Results: This study revealed that results of tubal manometry in diseased ears cover a wide spectrum of normal function to partial/non-function. 51.72% of cases were able to equalize applied negative pressure, 41.39% partially equalizing, while 6.89% of cases were completely unable to equalize applied negative pressure. Conclusion: Our results of aspiration method with the help of BM apparatus explicitly suggest that tubal function in chronically diseased ears deviates from that of normal ears. It perpetually reflects that varied results of middle ear reconstructive surgeries could be anticipated in accordance with different tubal function gradings.
Keywords: Bortnick-Miller apparatus, Chronic suppurative otitis media, Eustachian tube
|How to cite this article:|
Pandey AK, Gupta S C, Singh M. A simplified approach to assess variations in Eustachian tubal ventilatory function by Bortnick-Miller apparatus in chronic otitis media cases (dry) before surgery. Indian J Otol 2011;17:113-6
|How to cite this URL:|
Pandey AK, Gupta S C, Singh M. A simplified approach to assess variations in Eustachian tubal ventilatory function by Bortnick-Miller apparatus in chronic otitis media cases (dry) before surgery. Indian J Otol [serial online] 2011 [cited 2019 Jun 18];17:113-6. Available from: http://www.indianjotol.org/text.asp?2011/17/3/113/91190
| Introduction|| |
It is unanimously accepted that disorders of the Eustachian tube More Details contribute to the development and course of middle ear disease and its variants. ,, Hence, pathophysiology of the Eustachian tube bears paramount importance and also remains a challenge to the most astute and experienced otologist, who tries to reconstruct diseased ears. For this reason tubal function must be diligently checked in all patients with tympanic membrane or middle ear defects before reconstructive middle ear surgery. There exists a constant physiological tendency toward creation of negative intra-tympanic pressure ascribed to absorption of oxygen by the mucosa. A perfect and lasting operative end-result with adequately aerated tympanum could only be achieved if there occurs intermittent opening of the Eustachian tube, since this overcomes the acquired negative pressure and restores the middle ear pressure to normal. Being in continuity any pathology in the nose and nasopharynx is likely to affect the Eustachian tube, and thereby jeopardize its normal functions and imminently of the middle ear also. It is thus of interest if a tubal function test can quantify the tubal function deviations from normal and can also prognosticate the probable results of reconstructive middle ear surgery.
The aim of this study is to evaluate the ventilatory function of Eustachian tube in chronic suppurative otitis media cases (inactive stage) by tubal manometry, planned to undergo middle ear reconstruction and, hence to relate them with similar past experiences.
| Materials and Methods|| |
The present study consists of 29 cases of chronic suppurative otitis media (tubotympanic type) destined to myringoplasty/tympanoplasty. All patients were taken from Department of Otorhinolaryngology and Head and Neck Surgery during the period of August 2004 to November 2005. A complete history was taken and a complete local, general and systemic examination was carried out in all patients. Otoscopic findings were noted concerning tympanic membrane perforation - site and size, color of ear drum remnant, any tympanosclerotic patch, condition of middle ear mucosa, condition of ossicles, Eustachian tube orifice etc.
A ''U''- shaped glass tube was filled with mercury and the tube ends were calibrated above the meniscus of the mercury [Figure 1]. Then, one arm of U-tube was joined to one arm of a Y tube connector via a rubber tube. The second limb of the Y-connecter was attached to a No. 14 Foley catheter and the third, remaining arm of the Y-tube was attached with a calibrated 2 c.c. syringe. The calibrated syringe is meant for applying either a positive or a negative pressure, not to exceed 30 mm of mercury. If the applied negative pressure is completely neutralized after swallowing, then the tubal function is assigned normal functioning. In a hypo functioning tube the residual negative pressure, which remains in system after ten swallows, is arbitrarily termed as the functional capacity of the tube under negative pressure. When applying positive pressure, the patient is advised not to swallow and the air is pushed inward by calibrated syringe. The least amount of positive pressure needed to open the Eustachian tube passively is the functional capacity of the tube under positive pressure. Thus all the patients were classified in following groups according to following criteria [Table 1].
|Table 1: Distribution of tubal function gradings in dry ears (CSOM) as measured by BM apparatus |
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| Observations|| |
The present study includes 29 dry cases of C.S.O.M. with a central perforation having unilateral or bilateral disease. Preoperative Eustachian tube function in these cases was assessed by B-M apparatus. These 29 cases were divided according to their respective grades of tubal function [Table 1]. 15 out of total cases completely equalized the applied pressure, 12 cases had hypofunction, while 2 had non-functioning tubes. The average swallows required to equalize negative (-ve) pressure was 5, whereas the average positive (+ve) pressure to open the tube was 26 mm Hg.
| Discussion|| |
The physiological function of the tube is divided into three parts. First, its pressure equalizing function. Under normal conditions gases in the middle ear are slowly absorbed creating a negative pressure in the middle ear cleft. The tube, which remains collapsed at rest, opens intermittently and permits the passage of air from the nasopharynx into the middle ear thus equalizing the pressures. If the pressure gradient is reversed, air may pass in the opposite direction from the middle ear to the nasopharynx. Second, its drainage function. This function bears significance in middle ear surgery since adequate clearance of middle ear hastens healing of mucosal epithelium, whereas poor drainage yields poor outcome.  Third, its protective function. The resting tube protects the ear from noise and pressure changes in the nasopharynx, and perhaps acts as a barrier to infection.
Hypofunction of the tube leads to a conglomerate of pathologic changes of the middle ear and hearing disorders. Acute and chronic inflammatory processes involving the mucosa of the middle ear cleft as a whole and presence of small lymph follicles in the tubal lumen account common causes of obstruction or inadequate patency of the tube. Hypofunction of the Eustachian tube leads to serous otitis, which often heralds onset of acute otitis media, eventually resulting in acute mastoiditis or turning into chronicity and produce tympanosclerosis, cholesteatoma, or mastoiditis.
Several otologists have devised to achieve an ideal and perfect technique to assess ET function correctly. Zoellner pioneered in devising the air pressure resistance level measure which measures the tubal opening pressure by introducing an air stream of constant pressure into the closed nasopharynx via the nose.  The Eustachian tube opening pressure is determined either by noting the noise of escaping air through the eardrum perforation or by observation of outward movement of the eardrum under magnification. It is then recorded as air pressure resistance level in millimeters of water. In the past, such tests have been described by several otologists. ,,, In recent times, this primitive set up still holds its significance and such methods with minor modifications have also been elaborated by several otologists. ,,,,
The air pressure equalization test evaluates the capacity to normalize high air pressure gradients over the Eustachian tube and it may be useful in predicting the outcome and long-term success in tympanoplasty. ,,, Miller observed that out of 180 ears, 80% balanced a positive pressure and 43% only a negative pressure.  Flisberg observed that out of 102 ears infected with chronic otitis, 58% of the subjects are able to balance an overpressure and 42% only an under pressure. 
Miller cited that the correlation of poor tubal function with diseased middle ear mucosa probably reflects a similar pathological change in the tubal mucosa, which is the actual inciting event behind the poor tubal function.  It seems reasonable to infer that in such actively diseased ears tubal function expresses variability, and an impaired functioning Eustachian tube is dramatically capable of reverting to normalcy with elimination of infectious pathology in its mucosa. 
Miller categorically mentioned that the "ear aspiration method" is a precise method of determining the degree of tubal function as well as its anatomical patency. The residual negative intratympanic pressure is the most sensitive parameters of all tubal function that could be evaluated with this technique. The normal tubal function reveals complete neutralization of applied positive and negative intratympanic pressure, both, with the ambient pressure. He further corroborated that, the tubal function in chronic otitis media is impaired as compared to that of normal ears. There occurs a wide variation in tubal function among diseased ears ranging from normal to non-function. The condition of the middle ear mucosa seems to be the most decisive pathological factor correlated with tubal function in ears with CSOM. Tubal function in ears having a thickened and inflamed mucosa may express significant variability, poor function often reverts to normal with eradication of inciting foci causing mucosal inflammation. This technique proves to be an important screening tool in the selection and timing of patients chosen for reconstructive middle ear surgery which, to be successful, necessitating normal or near normal tubal function. 
Gersdorff observed that, in cases of tympanic membrane perforation, even without middle ear discharge one is surprised by the high degree of residual under pressure. It frequently reveals an impairment of the tubal mucosa, a classical feature in ear diseases with tympanic perforation. The advantages shown by this technique thus become obvious when surgical reasons for tympanoplasty are being considered. It is necessary to be able to properly gauge the importance of endotympanic under pressure, which will be located under the tympanic graft, as the successful outcome of surgery will partly depend on it.  In our series, there were 51.72% cases completely equalizing -ve pressure and 41.39% equalizing partially and 6.89% were unable to equalize -ve pressure completely. Miller and Bilodeau evaluated tubal function by BM apparatus in 22 ears of their series planned for simple myringoplasty and found that 17 (77.27%) cases had good tubal function, 3 (13.64%) cases had tubal function with only positive pressure, while 2 (9.09%) cases had no demonstrable tubal function. 
Kacker et al. evaluated 46 ears with dry perforation having quiescent CSOM. There were 30.44% of cases having normal ET function, 65.22% of cases having hypofunction and 4.34% of cases were having non function. In that series, the average swallows required to neutralize the applied -ve pressure was 3.3 whereas the average +ve pressure to open the tube was 30.3 mmHg.  In our series, average swallows required to equalize the -ve pressure was 5 and tubal opening pressure was found to be 26 mmHg and it is in accordance with the various authors [Table 2]. On the basis of average negative and positive pressure to open the tube, Kacker et al. enumerated accordingly different functional gradings of the Eustachian tube in cases of various pathological conditions of the middle ear. The tubes were leveled as hypofunctioning, if pressure needed to open was more than 30 mmHg but less than 60 mmHg. When pressure needed exceeds 60 mmHg, it was leveled to be non-functioning or blocked. 
Srivastava et al. performed the tubal manometry in 27 ears by using B-M apparatus after creating negative pressure in the middle ear; normal functioning tubes were found in 74.08%, hypofunctioning in 14.80% and non-functioning (blocked) in only 11.12% ears. The average positive pressure needed to open the tube was up to 30 mmHg (74.08%) and this was assigned to be normal functioning tube.  In our series, normal Eustachian tube function was present in 51.72% cases, hypofunction in 41.39% cases and non-function in 6.89% cases. Bhat et al. devised a Eustachian barotubometer and tested tubal function in 31 cases having quiescent CSOM. In 25 cases, tube was patent, 5 had partially patent tube, and 1 case had blocked tube. They interpreted that Eustachian barotubometer is a safe, reliable and cost effective modality to appropriately quantify pre-operative tubal function. Its usefulness lies in that, it does not require power supply and is portable. 
Thus our results confirm the conclusion that the Eustachian tubal function in of chronic otitis media cases definitely deviates from that of normal ears [Table 3]. Ekvall evaluated 39 chronic otitis media cases planned for middle ear surgery by performing negative ear- aspiration method and found that, 54% were unable to equilibrate a negative pressure applied to the middle ear. 
|Table 3: Eustachian tube function among normals and diseased in various series |
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Srivastava et al. concluded that, B-M apparatus can be efficiently and satisfactorily used as an office procedure, being inexpensive too. Different tubal function gradings along with anatomical patency can also be determined.  Kumazava et al. stated that, the inability to relieve the negative middle ear pressure by swallowing is considered to be a characteristic of Eustachian tube dysfunction in OME. Studies of Eustachian tube function in patients with chronic otitis media and cholesteatoma may be useful to predict the prognosis in cases of tympanoplasty. 
| Conclusion|| |
It seems prudent to precisely determine the tubal function preoperatively in perspective of extent of its variability in chronic otitis media cases, as it is purported to be predictive of the outcome of reconstructive middle ear surgery. The "negative middle ear pressure test" as assessed by BM apparatus seems undoubtedly useful as screening method in primary setup, where tympanometric facilities are not available, in decision making regarding appropriate time and suitable surgical candidacy of a perforation closure by myringoplasty. It is at present felt that provided a middle ear is, by microscopic examination, both dry and showing no evidence of any active inflammatory process, it is wisely advisable to close a perforation in the presence of "good" or "moderate" grades of Eustachian function. Patients who cannot reduce a negative pressure applied to the middle ear are much less likely to have a satisfactory surgical outcome, although not necessarily, from myringoplasty and this risk must be explained prior to the candidate before contemplating surgery.
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[Table 1], [Table 2], [Table 3]