Relation Between Eustachian Tube Function And Myringoplasty:

Hosam El-din Mahmoud Abdel-bakl

It is now widely accepted that Eustachian tubedysfunction has a definite role in the pathogenesis of otitismedia. Also the effect of chronic inflammation in worseningthe Eustachian tube function is well known.Being an integral part of the middle ear physiology,siedentop et ale (1978) mentioned that a successful surgicalrepair of drum perforation depends upon a normallyfunctioning ET. There is a lot of contoversy about the roleof ETF and its value in the prediction of the outcome ofmiddle ear reconstructive surgery. While some authors likeMackinnon (1970) and Bolaquiat (1969) found a goodcorrela.tion between preoperative ETF and the success rate oftympanoplasty, Flisberg (1966) considered that a recordedtubal hypofunction as a highly unfavourable prognostic signin tympanoplasty, even contraindication to reconstructivesurgery. others, sheehy and Glasscok (1967) had a goodhealing rate in their series of tympanoplasty mentioningnothing about ETF tests.Aims of the york :Trying to investigate this controversy, this study wasplanned aiming at :1- Trying to correlate between preoperative ETF and theoutcome of myringoplasty regarding healing and hearingimporvement. Trying to find any significant relationthat can exist between preoperative ETF and result ofmyringoplasty ventilatory function of ET was assessedpreoperative by ;inflation-deflation test, valsalva’s testand Toynbee’s test.2- Recroding any postoperative change of ETF. For thispurpose ETF was tested by valsalva’s test, Toynbee’s testand tympanometry. In this way it can be found out, incases with successful myringoplasty, to which extent theETF is affected by closure of the tympanic membraneperforation.Patients included in the study :120 patients were included in this study. They had chronicsuppurative otitis media, mucosal disease with a drycentral perforation. It was made sure that there was noear discharge at least for 3 months prior to the surgery.Non of them had cholesteatoma, granulation or tympanosclerosis.Kethode ueed IEach patient was SUbjected to1- Full history.2- Ear, nose and throat examination.3- Pure tone audiometry.4- Pre-operative assessment of the ventilatory function ofEustachian tube by :- Valsalva’s test- Toynbee’s test.Inflation-defletion test which wasmethod described by 8iedentop et &1.done following the(1972) and the ETFwas classified in this way into 5 types : I, II, III, IVand V according to the ability of ET to equilibratenegative of -250 mmH20 and positive pressure of+ 500 mmH205- Myringoplasty was done using the underlay technique andtemporalis fascia graft.6- Postoperative follow up to find out :a- Success rate.b- Cases with successful myringoplasty were sUbjected 6months after the operation to :- Clinical examination and testing drum mobility.- Pure tone aUdiometry was done to find out the degree ofimprovement.- Postoperative valsalva and Toynbee’s test were done aswell as Tympanometry as tests for ETF.Result. :1- Preoperative ETF testing: it was found that valsalva’stest was positive in 60’ of patients, Toynbee’s test waspositive in 65’ of the patients.For inflation Deflation test : 8.33’ of patients hadtype I ETF, 20’ had type II ETF, 53.33’ had type III ETF and18.33’ had type IV ETF. Non of the patients had type V ETF.2- Healing results : successful myringoplasty was obtainedin 100 patients representing 83.33’ of the whole group ofpatients. Success rate was higher in patients with type Iand II ETF (90’ and 87.5’ respectively). While it was-126-lower in patients with type IV ETF, namely 68.18% but thisdifference was found to be insignificant.3- Hearing results : All the patients included in this studyhad conductive hearing loss. Non of them had mixed orsensorineural hearing loss. The mean preoperative A-B gapwas 21.42 dB while postoperative A-B gap was 15.3 dB.Patients with A’;”’Bgap from 0-20 dB were 33.33%preoperatively while postoperatively they were 73%. ForA-B gap of 20-30 dB preoperatively 66.67% of patients wereincluded while postoperatively they were only 27%. Thus itcan be deduced that, there is a significant and definitehearing improvement of the whole group. It was found also,that there was a significant difference in hearingimprovement between patients of type I ETF (good function)and type IV ETF (poor ETF); as for patients type I ETFthose with postoperative A-B gap 0.20 dB represented88.88t and those with type IV ETF they represented 46.66t.4- Postoperative ETF showed improvement as shown byvalsalva’s test which changed from being positive in 60tof patients preoperatively to be positive in 83% ofpatients with successful myringoplasty. Also Toynbeeshowed a similar chanqe from beinq positive in 65% ofpatients preoperatively to be positive in 84% of patientspostoperatively.Tympanometric studies showed that patients with type Acurve are 50% of the total qruop while it was 33.33% ofpatients with type IV ETF. In the same time type C curve wasfound in 37 of the whole group while found in 40 ofpatients with type IV ETF. The difference is insignificantwhich means postoperative improvement of ETF in patients withtype IV ETF.Conclusions z1- It is important to assess the ventilatory function priorto myringoplasty. The· inflation-deflation test is areliable one. Also Toynbee’s test proved to be a sensitiveone and can be used as a screening test.2- Good preoperative ETF can predict good healing and hearingresults of myringoplasty. In the presence of poorpreoperative ETF the healing results are inferior to thoseof patients with good ETF although the results are stillgood results while hearing improvement is markedlyinferior to that of patients with good ETF.3- There is marked postoperative improvement of ETF. due toclosure of tympanic membrane perforation4- A good tubal function is a prerequisite for a successfulmyringoplasty while a bad function does not contraindicatemyringoplasty.5- Patients with preoperative poor ETF should be followed upmore thoroughly postoperatively as they are more subjectedto develop negative middle ear pressure and hencesecretory otitis media.