Reversible canal wall down mastoidectomy for acquired cholesteatomas: preliminary results.

OBJECTIVES: The educational objectives were to discuss a new technique to manage acquired cholesteatomas and to compare this with standard approaches used for cholesteatoma removal. The study objective was to determine the feasibility of using a new approach, the reversible canal wall down approach, in conjunction with bone cement to remove acquired cholesteatomas and, potentially, preserve the ossicular chain. STUDY DESIGN: Retrospective review of five patients who underwent resection of their acquired cholesteatomas using a technique that maximizes exposure, yet preserves the posterior canal wall and, potentially, the ossicular chain. METHODS: In the setting of a tertiary otological referral center, five consecutive patients with acquired cholesteatomas underwent reversible canal wall down surgery. Four patients were male (ages, 41, 53, 26, and 10 y), and one patient was a woman [age, 51 y]). A reversible canal wall down mastoidectomy approach was used in the patients. Main outcome measures were intraoperative findings with respect to cholesteatoma removal and postoperative clinical examination, including postoperative audiograms. RESULTS: Five patients had dry ears postoperatively. One patient initially had granulation tissue forming on the posterior ear canal. This eventually resolved. The patients who had a postoperative audiogram after cholesteatoma resection with ossicular chain preservation noted an improvement or stabilization in their hearing. CONCLUSIONS: Using the reversible canal wall down approach in conjunction with bone cement, one is able to obtain excellent exposure of the cholesteatoma and, potentially, preserve the ossicular chain. This approach may be particularly useful in revision cholesteatoma surgery or in cases of acquired cholesteatoma in which the surgeon may be able to preserve the ossicular chain.

Effect of round window membrane application of nitric oxide on hearing and nitric oxide concentration in perilymph.

Nitric oxide (NO), a free radical, has been found to be important in the development of middle ear effusions. However, the effect of NO in the middle ear effusion on cochlear function and on perilymph concentrations of NO has not been reported. We placed S-nitroso-N-acetylpenicillamine (SNAP), a NO donor compound, on the round window membrane (RWM) of adult chinchillas. Auditory brainstem response (ABR) thresholds were measured before and after the placement of SNAP on the RWM and hourly for 8 h after SNAP placement. Samples of perilymph were collected 2 h after application of SNAP and were assayed for total nitrate and nitrite, the end products of NO. Experimental ears demonstrated significant ABR threshold elevations after 5 h and elevated nitrate/nitrite in the perilymph. These findings suggest that NO present in the middle ear passes through the RWM into the inner ear and can cause significant hearing loss.