Does Checking the Placement of Ossicular Prostheses via the Posterior Tympanotomy Improve Hearing Results After Cholesteatoma Surgery?

INTRODUCTION: Posterior tympanotomy (PT) is often performed during the surgical management of middle ear cholesteatoma with extension in the retrotympanum area. This PT can also be used to control the right position of the ossicular prosthesis masked by the tympanic membrane reconstruction. OBJECTIVE: To compare audiologic results after ossiculoplasty performed via the outer ear canal and via the PT for patients with cholesteatoma. MATERIALS AND METHODS: Retrospective chart reviews were performed for 68 patients (68 ears) with cholesteatoma who underwent titanium ossicular prosthesis surgery between January 2007 and January 2011. We compared audiologic results between two groups: the WPT group (the group without checking the prosthesis via the PT) and the PT group (the group with placing and/or checking the prosthesis via the PT). A postoperative pure-tone average air-bone gap of 20 dB or less was considered a successful hearing result. RESULTS: Of the patients who underwent canal wall-up mastoidectomy for cholesteatoma with ossicular chain reconstruction by titanium prosthesis, 36 patients (20 total ossicular replacement prosthesis [TORP], 16 partial ossicular replacement prosthesis [PORP]) were in the PT group and 32 patients (16 TORP, 16 PORP) were in the WPT group. The global success rate (defined as a mean residual air-bone gap < 20  dB) was 50% in the WPT group (56% in the subgroup PORP, 44% in the subgroup TORP) and 42% in the PT group (62% in PORP, 25% in TORP). There was no case with extrusion of the prosthesis in either group. No facial palsy occurred during the postoperative period for either group. CONCLUSION: Control of ossicular prosthesis positioning via the PT does not improve hearing results after ossicular chain reconstruction in cholesteatoma surgery. However, this approach can be used during a second-stage procedure that avoids incisions within the external ear canal.

Bone quality and biomechanical function: a lesson from human ossicles.

In humans, the middle ear contains a chain of three ossicles with a major highly specific mechanical property (transmission of vibrations) and modeling that stops rapidly after birth. Their bone quality has been rarely studied either in noninflammatory ossicles or in those from ears with chronic inflammation. Our primary goal was to assess bone microarchitecture, morphology and variables reflecting bone quality from incuses, in comparison with those from human femoral cortical bone as controls. Secondly, the impact of chronic inflammation on quality of ossicles was documented. The study was performed on 15 noninflammatory incuses from 15 patients (35±32 years, range: 2-91). Comparisons were performed with 13 inflammatory incuses from 13 patients (55±20 years, range: 1-79) with chronic inflammation of the middle ear, essentially cholesteatoma. Microarchitecture and bone mineral density (BMD) were assessed by microcomputed tomography. Microhardness was measured by microindentation. Mineral and organic characteristics were investigated by Fourier transform infrared microspectroscopy. Noninflammatory incuses were composed of a compact, well mineralized bone without bone marrow and with sparse vessels. Remodeling activity was rarely observed. Woven or lamellar textures and numerous osteocytes were observed. In inflammatory incuses, architecture was degraded, organic tissue was abundant and bone cavities contained fibrocellular tissue and adipocytes. BMD of noninflammatory incuses was significantly higher than BMD from both control bones (4 embedded cortical femoral bone samples; age: 72±15 years, range: 50-85) and inflammatory incuses. Noninflammatory incuses were less hard than both control bone (8 cortical femoral bone samples; age: 49±18 years, range: 24-74) and inflammatory incuses. All incuses were more mineralized and less mature than controls. In conclusion, bone quality of incuses (dense, well mineralized, hard) is well adapted to their function of sound transmission. In inflammatory condition, incuses were degraded, thus explaining the decline of hearing. Moreover, microhardness was found higher than in noninflammatory incuses. Compared to bone with remodeling, the mineralization index in incuses does not explain variation of microhardness. Interestingly, a linear multiple regression model indicated that a combination of two variables, i.e., crystallinity index (crystal size/perfection) and carbonation (incorporation of carbonate ions in apatite) explains 26% of the increase in microhardness variability. Because the low remodeling level of ossicles could not prevent the reversibility of their degradation which impacts audition quality, an early management of ear inflammation in chronic otitis is recommended.