Symposium on tympanoplasty. I. Results of modified type V tympanoplasty.

Abstract

AbstractModified Type V tympanoplasty has been used in this series to improve hearing in unsuccessful Type IV tympanoplasties and also to preserve cochlear function and possibly to improve hearing in cases where the oval window has been inadvertently opened during chronic ear surgery. Modified Type V tympanoplasty refers to removal of the stapes footplate with replacement by adipose tissue in the oval window. A tympanoplasty graft is then placed over the tissue graft and hearing achieved by round window protection with an air‐containing hypotympanum. The concept of modified Type V. tympanoplasty has been described by Del Villar,1 Paparella,2,3 Sato,5 and Proctor4 previously. Results from these previous authors have been somewhat variable, and this series is presented in an attempt to evaluate this procedure more clearly. Modified Type V tympanoplasty was, therefore, performed on 20 ears, 14 of these on ears that had previous Type IV tympanoplasty with unsuccessful hearing levels. The remaining six ears received the Type V tympanoplasty at the initial surgery, usually because of inadvertent fracture or avulsion of the stapes footplate. Thirteen ears achieved a significant improvement in hearing with an average gain in air conduction of about 19 decibels for the speech frequencies. The average improvement in the conductive component of the hearing loss was 22.4 db, while no loss of bone conduction or discrimination followed. Five cases obtained no change in hearing and retained bone conduction and discrimination scores so that amplification was still possible. Two instances of sensori‐neural loss were incurred: one a total loss of auditory function in a previously dry ear, while a partial loss of function with still useful discrimination score was present in the second case, one that had been wet at the time of surgery.The results indicate that the modified Type V tympanoplasty is a useful procedure to improve hearing in unsuccessful Type IV tympanoplasties, where the probable reason for the poor hearing result is stapes fixation with fibrous tissue, tympanosclerosis, or otosclerosis. Modified Type V tympanoplasty may also be used to preserve cochlear function at mastoid surgery where the stapes footplate has been inadvertently fractured or avulsed. In addition, hearing improvement may also be obtained in these instances where modified Type V is performed emergently during mastoid surgery.