Hearing Results in Reconstructing the Damaged Incus With Varying Lengths of the Modified Lippy Prosthesis

Abstract

Evaluate success of reconstructing the damaged incus in otosclerotics and chronic ear disease with the use of the modified Lippy prosthesis. Maintaining ossicular continuity is critical in optimizing sound transfer particularly when there has been incus erosion of varying degrees. Our hypothesis was that the varying lengths of the Lippy modified prosthesis would allow for reconstruction of the incus with very good results. Clinical records were reviewed from 1998 to 2009. Fifty-four patients requiring incus reconstruction with the modified Lippy prosthesis were evaluated. Analysis was done of type of surgery, varying lengths of incus erosion and lengths of prostheses used. Audiometric outcomes were evaluated with respect to length of prosthesis and type of surgery performed. Audiometric evaluation of 4 frequency closure to within 10 dB air-bone gap (ABG). Audiometric results for the 54 patients revealed a mean postoperative ABG of 7.8 dB with mean follow-up of 7.4 months. Closure of ABG within 10 dB was achieved in 74.1% of patients, and 96.3 % achieved closure within 20 dB. Long-term follow-up at 51 months for a subset of 15 patients demonstrated a mean postoperative ABG of 15.5 dB. No relation was found between prosthesis length and ABG at both the initial and long-term postoperative evaluation. Incus erosion presents a significant challenge in middle ear reconstruction. The otologic surgeon must be prepared to perform incus reconstruction whether in otosclerosis or in chronic ear surgery. Knowledge in use of the modified Lippy prosthesis enables the surgeon to deal with varying degrees of incus necrosis yielding very good hearing results.