EVALUATION OF MIDDLE EAR PNEUMATIZATION AFTER PLANNED TWO-STAGED TYMPANOPLASTY FOR CHOLESTEATOMA: ITS CORRELATIONS WITH HEARING RESULTS AND RECURRENCE RATES
Introduction
The middle ear (ME) is lined by a mucosa that embeds a network of blood vessels. The ME should function to passively exchange gases with the local blood across their respective mucosa in the normal condition – therefore, decrease in ME volume and poor ME mucosal function might predispose to certain pathological conditions, including cholesteatoma.1,2
After a planned two-staged tympanoplasty for cholesteatoma cases, the reconstructed and pneumatized ME could be lined again by a mucosa and the restored ME function might lead to a good hearing result as well as a low recurrence rate of cholesteatoma.
Materials and methods
A planned two-staged tympanoplasty was performed in most cases with advanced cholesteatoma. At the first stage of surgery (operation 1), cholesteatoma was completely eradicated and the anterior attic bony plate was widely opened (Fig. 1A,B), then two silicon sheets were placed into the ME (Fig. 1C,D), and finally the tympanic membrane was formed with a fascia of temporal muscle. The external ear canal was reconstructed using the soft-tissue wall technique. At the second stage (operation 2), after taking the silicon sheets out and searching for residual cholesteatoma, both the ossicular chain and the external ear canal were reconstructed with cartilage plates from auricle or tragus.
The ME pneumatization was determined by several CT scans according to the 0–5 rating system (Fig. 2) (score 0: none; 1: pneumatized ET orifice; 2: mesotympanum; 3: attic; 4: antrum; 5: mastoid). Correlations of ME pneumatization with hearing results as well as recurrence rates of cholesteatoma were evaluated.
Results
In 76 cases (82 ears) with acquired cholesteatoma among the patients who received the surgery at Osaka University Hospital between 2000 and 2009, CT scans were examined at least twice at any time of before operation 1, before operation 2, and after operation 2. There were 35 males (37 ears) and 43 females (45 ears), and the median age was 42 years (range 4–75 years). In one case (50-year-old male), the scores of the ME pneumatization were rated at 0 before operation 1 and at 5 before operation 2, indicating its significant improvement within just one year (Fig. 3).
Fig. 1. Insertion of two silicon sheets into the ME at the first-stage surgery.
Fig. 2. The 0–5 rating system of ME pneumatization.
The average ME pneumatization was 2.65 before operation 1 and 3.45 before operation 2 (Fig. 4A, N = 35), and it was 3.14 before operation 2 and 4.29 one year after operation 2 (Fig. 4B, N = 21). These improvements of the ME pneumatization were statistically significant (P < 0.05) for both evaluations. The ME pneumatization tended to continuously improve for a certain period of time even after operation 2 (N = 34). The mean follow up was 727 days after operation 2.
Hearing results (80% success) in patients with well-pneumatized ME (rated at 3–5; N = 27) after operation 2 was not significantly better (P > 0.05) than those (50% success) in patients with poorly pneumatized ME (rated at 0–2; N = 29). The mean follow up was 941 days after operation 2.
The ME pneumatization after operation 2 (2.8) in patients with recurrences/retraction pockets (N = 7) was significantly (P < 0.01) worse than that (4.55) in patients with no recurrence of cholesteatoma (N = 59). The recurrence rate of cholesteatoma was 5.6% (mean follow up: 1497 days after operation 2).
Fig. 3. Improvement of the ME pneumatization after operation 1.
Fig. 4. Improvement of the ME pneumatization after operation 1 and operation 2.
Discussion
With a planned two-staged tympanoplasty, the ME pneumatization improved significantly one year after operation 1, and it tended to improve continuously for a certain period of time even after operation 2. Good vibrations of TM, stable placements of columella resulting from a reconstruction of the well pneumatized ME should contribute to a good hearing result and a low recurrent rate of cholesteatoma. In some cases, the ME pneumatization was poor before and after operation 2, presumably due to a dysfunction of the Eustachian tube. A ventilation tube should be inserted at the second stage, if the ME pneumatization is found to be poor before operation 2.
Reconstruction of the well-pneumatized ME and restoration of the ME function might be crucial to good hearing results and low recurrence rates in tympanoplasty for cases with cholesteatoma.
References
1.Swarts JD, Doyle BM, Doyle WJ. Relationship between surface area and volume of the mastoid air cell system in adult humans. J Laryngol Otol 125(6):580–584, 2011
2.Ann J-Y, Park H-J, Park GH, et al. Tympanometry and CT measurement of middle ear volume in patients with unilateral chronic otits media. Clin Exp Otorhinolaryngol 1(3):139–142, 2008
Address for correspondence: Katsumi Doi, MD/PhD, 377–2, Oono-Higashi, Osaka-Sayama, 589–8511, Osaka, Japan. kdoi@med.kindai.ac.jp
Cholesteatoma and Ear Surgery – An Update, pp. 59–61
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands