Use of incus as an interposition graft in ossiculoplasty for type IIb tympanoplasty

Abstract

Background: In cases of chronic suppurative otitis media, the most common cause for the discontinuity in the ossicular chain is erosion of lenticular or long process of incus. To study hearing results, sequel and complications of using autologous incus as interposition graft in type IIb osiculoplasty. Methods: We studied 30 patients who required ossiculoplasty using autologous incus. The pre-operative audiograms were done. Post operatively patients were followed up to 2 years during which complete otological examination with audiogram was done. Results: According to the American Academy of Otolaryngology-Head and Neck Surgery guidelines, a successful hearing result is the one with post-operative air-bone gap of 20 decibels or less. Hence, by this standard our success rate is 77 percent and in all of our patients we have air-bone gap closure to below 30 decibles. Average closure in air-bone gap (gain) in our patients is 25.9 decibles with average pre-operative and post-operative air-bone gap being 47.70 decibles and 16.9 decibles there was no extrusion of incus. 3 patients had residual perforation and 2 patients had retracted grafts. All the patients with retracted grafts or residual perforation had oedematous middle ear mucosa and Eustachian tube dysfunction and high MER index. Conclusions: Autologous incus is an excellent interposition graft for ossiculoplasty. There is no risk of transmission of disease and no extra cost involved. Higher values of Middle Ear Risk Index, oedematous middle ear mucosa and Eustachian tube dysfunction are poor prognostic factor for success of ossiculoplasty.