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Outcome of Interlay Type 1 Tympanoplasty for Large Central Perforation

Background: Perforation of the tympanic membrane may occur from various reasons. Most of these perforations heal spontaneously, whereas the remaining long-standing perforations that lead to recurrent ear discharge need tympanoplasty. Interlay Type 1 Tympanoplasty,a newer technique has shown promising results with higher success ratein terms of hearing gain and graft uptake. Objective: To analyze the results of interlay Type 1 Tympanoplasty in terms of graft uptake and hearing improvement in cases of inactive mucosal chronic otitis media (COM) with large central perforation. Methods: This is a prospective study of 24 months (January 2018 to December 2019) duration conducted in department of E.N.T, Khulna medical college, Khulna and data was collected from the 60 patients admitted for tympanoplasty. Results were calculated in terms of graft accepted or rejected and decrease in air bone gap. Result: The graft uptake rate in the present study was found to be 91.67% and the patients reported an improvement in terms of hearing. Pre operatively mean air bone gap was 26.5dBand post operatively after 12 weeks mean air bone gap improved to 17.58dB. Conclusion: Interlay Type 1 Tympanoplasty is an effective technique over conventional methods in terms of both graft uptake as well as hearing improvement in large central perforation


Introduction:
Chronic otitis media (COM) is a major health problem in a developing country like Bangladesh, especially in low socio economic strata (prevalence >10%). COM has a major impact on the social life of a person in the form of hearing disability 1 . The discharge from the ear is also troublesome causing great discomfort to the patient.
Perforation of the tympanic membrane primarily results from middle ear infections, trauma or iatrogenic causes. Up to 80% of these perforations heal spontaneously 2 . For the remaining, surgical repair, known as tympanoplasty, is usually proposed.
Tympanoplasty is a procedure done to repair the defect in the tympanic membrane after eradicating all the disease in the middle ear cleft with or without reconstruction of ossicularchain 3 . Type I tympanoplasty is a surgical technique that involves the repair of the tympanic membrane in cases where the only existing lesion is a tympanic membrane perforation. It is the most common otological procedure after myringotomy 4 . Tympanoplasty is one of the most commonly done otological procedure. It was introduced by Berthold

Results:
The present study comprised of total 60 patients of which 27(45%) were male and 33(55%) were female patients. The age of the patients ranged from 17 to 60 years, with the mean age group32.53 years with standard deviation 9.37. Maximum number of patients were in the age group of 21 to 30 years.  Post operatively graft accepted in 55(91.67%) patients while graft rejection was observed in 5(8.33%) patients at the end of 12 weeks as shown in figure-1.  Figure 1 At the end of 12 weeks the postoperativemean ABG was reduced to 17.58dB with standard deviation6.88and the postoperative ABG changing to less than 10 dB in 8(13.33) patients, between 11 and 20 dB in 38(63.33) patients and between 21 and 30dB in 11(18.33%) patients andno improvement in 3(5%) patients, all of which were statistically significant.

Discussion
Bangladesh is one of the countries with highest load of chronic otitis media 18 . It is important being a curable cause of deafness. It is mostly the end result of acute otitis media and is characterized by deafness and Figure 2 persistent discharge from the middle ear through a tympanic membrane perforation.
Tympanoplasty is the operative procedure performed to repair the perforation in ear drum by repairing the tympanic membrane 6 . It is a beneficial procedure to protect the middle ear and inner ear from future damage. Improvement in hearing sensitivity is also observed 19 . Tympanoplasty has come a long way after it was first introduced by Wullstein and Zollner in the early 1950s 20 as there was a constant desire to improve the technique as well as outcomes. In the past few years, interlay technique of tympanoplasty hasgained a lot of popularity and has emerged as the preferred approach because of its low incidence of complications and promising results.
In the present study, the graft uptake rate was found to be 91.67% which is in accordance with study by Kawatra  In the present study Only 5 (8.33%) patients had graft failure. There was no improvement in hearing in 3(5%) patients. Complication Occur in7(11.66%) patients which is consistent with the study by Patil et al 12 .

Conclusion:
Although interlayType 1 tympanoplasty technique requires additional expertise in surgery, it is an effective technique over conventional methods like overlay or underlay for graft uptake and hearing gain in large central perforation .The complications associated with this are less as compared toother techniques. This study indicate interlay is the best approach for chronic otitis media with large central perforation of mucosal variety.