'Tripod' Ossiculoplasty in Incudal Lesions

Abstract

\s=b\A method of ossiculoplasty, in cases where the long process of the incus is eroded, is described. The defect created by the erosion of the incus is bridged by an autogenic or allogenic bone graft that leans on the stapes, the remaining part of the incus, and the side of the malleus. These three contact points allow for stability of the bony graft and account for the name tripod. The method was applied in 30 ears and was successful in all but three cases. All the rest (ie, 27 ears) achieved an average gain of 24.8 dB, leaving an average air-bone gap of 11.1 dB. The postoperative air-bone gap was 20 dB or less in all 27 ears that were successfully operated on; and in 21 of them (77.8%), it was no more than 10 dB. The average period of follow-up was 23.8 months. Operative success depended on both the technique chosen and the favorable selection of cases. (Arch Otolaryngol Head Neck Surg 1989;115:596-599) The lesion most commonly found to interrupt the continuity of the ossicular chain is a defect of the long process of the incus.1·2 The most fre¬ quent cause of such a lesion is chronic otitis media of one form or another.Numerous surgical techniques to overcome this defect, employing vari¬ ous materials (eg, bone, cartilage, and (Dr Sad\l =e' \).holoplastic material), have been described.232 Although a relatively high success rate is usually claimed for most of these methods, problems of graft extrusion and optimal airbone gap closure have not yet been entirely solved. This is a description of a new and simple technique that we have found to be very satisfactory in overcoming the effects of erosion of the long pro¬ cess of the incus in the presence of an intact stapes. We describe our tech¬ nique and our results in cases that, from our point of view, were suitable for ossiculoplasty. MATERIALS AND METHODSThe gap created between the stapes and the body of the incus, as a result of the erosion of its long process, is bridged by means of a bony graft that rests on three points (Pigs 1 through 3): the head of the stapes, the remaining portion of the long process of the incus, and the posterior surface of the handle of the malleus.A bony allograft is shaped to fit into the space between the three ossicles, and is wedged in to lean on the above three points, without touching the medial wall of the middle ear. The allograft is shaped like a pyramidal wedge, with the tip pointing upward toward the space between the rem¬ nant of the incus and the handle of the malleus. Because the graft leans on three points, we refer to it as a tripod. The allograft may also be placed or wedged into its appropriate position without even touching the drum.Our experience has shown that because of the graft's pyramidal shape it can usual¬ ly be fitted into a stable position in any of the various spatial situations that may arise following erosion of the long process of the incus. The defect and the resulting interossicular gap may be very small, requiring a very small tripod; while at other times, a longer or larger tripod will be nec...

Tripod allograft in reconstruction of incudal lesions

“…up to the time of writing) was 41 months. Of the patients who were described in our previous study (Sade et al, 1989), 20 were available for a longer follow-up assessment and are therefore included in the present study as well. The average follow-up time for these 20 patients was 21 months at the termination of the previous study, and 65 months at the time of writing of the present study.…”