Erosion of the Long Process of the Incus in Revision Stapes Surgery

Abstract

To study hearing outcome in revision stapedotomy cases where extensive erosion of the long process of the incus was observed in a consecutive series where a malleovestibular prosthesis was used versus a consecutive series where hydroxyapatite (HA) bone cement was used to rebuild the eroded long process of the incus and integrate the prosthesis. Twenty revision cases of surgically treated otosclerosis where extensive incus erosion was observed during revision surgery. In the earlier consecutive series, 10 cases were treated with malleovestibular prostheses. In the later consecutive series, 10 cases were treated with HA bone cement to rebuild the incus-prosthesis interface. Air-bone gap, bone-conduction thresholds, and air-conduction thresholds were evaluated preoperatively and at 1 to 3 months. Last audiometry available also was reported (median, 12 mo). Pure-tone averages were calculated according to the guidelines of the Committee on Hearing and Equilibrium for the evaluation of conductive hearing loss. Raw data were displayed in an Amsterdam Hearing Evaluation Plot. Six male patients and 14 female patients were included. Age varied from 34 to 75 years (median, 53 yr). The median postoperative air-bone gap at last follow-up audiometry was 15.6 in the malleovestibular prosthesis group and 13.1 dB in the HA bone cement group. No short-term or intermediate-term adverse reactions or unsuspected bone conduction deteriorations were seen. HA bone cement can be successfully used to reconstruct the long process of the incus in case of extensive erosion of the long process. Intermediate-term hearing outcome is comparable to the outcome of a series of similar cases treated with malleovestibular prostheses. Because the placement of a malleovestibular prosthesis is technically more difficult and presents a high risk to the inner ear, we think HA bone cement can be a useful alternative in these difficult cases.