POST-OPERATIVE CONDITION FOLLOWING CANAL-WALL-UP TYMPANOPLASTY FOR PARS FLACCIDA CHOLESTEATOMA
Introduction
Our principle strategy for surgery in middle-ear cholesteatoma has been the canal-wall-up tympanoplasty (CWU). Although a well-pneumatized cavity after surgery is the goal of CWU, the extent of re-pneumatization varies widely between tube and mastoidectomy cavity. This study assessed the relationship between 1) the extent of cholesteatoma and re-pneumatized spaces after CWU; 2) the extent of cholesteatoma and hearing improvement after CWU; and 3) the extent of cholesteatoma and recurrence rate after CWU.
Materials and methods
One hundred and nine ears with pars-flaccida type cholesteatoma underwent CWU with anterior tympanotomy1 and scutum plasty at the University of Miyazaki Hospital from 1998 to 2004. All cases were followed up for more than five years.
Extent of cholesteatoma (staging)
Each ear was assigned to one of three groups according to the extent of the cholesteatoma demonstrated at surgery based on the staging criteria for cholesteatoma 2010 Japan: stage I: cholesteatoma localized within the attic (21 ears, 19%); stage II: cholesteatoma extends into the mastoid cavity (64 ears, 59%); stage III: large defect of the scutum and external auditory canal due to cholesteatoma extension (24 ears, 22%).
Distribution of pneumatization (pre-and post-operative CT)
Within three months before surgery and one year after surgery, a CT was performed in all patients. Each ear was assigned to one of four groups according to the degree of pneumatization: 1) no aeration; no aerated space within the middle ear; 2) mesotympanum; partially or totally aerated bony Eustachian tube, meso-, hypo-, and retrotympanum; 3) epitympanum; aerated tube, mesotympanum, and epitympanum, but no air space in the mastoid; and 4) mastoid; aerated from tube to mastoid antrum.2
The distribution of pneumatization (Fig. 1)
Figure 1 shows the distribution of pneumatization in 109 ears pre- and post-operatively. The tube/mesotym-panum group accounted for up to 74% on pre-operative CT. Ninety-four percent of the ears showed improved pneumatization after operation. The mastoid (47%) and epitympanum (16%) groups in particular showed significant improvement of post-operative pneumatization (p < 0.01, χ2 test).
Fig. 1. Distribution of pneumatization.
Re-pneumatization according to preoperative pneumatization (Fig. 2)
Fig. 2. Re-pneumatization according to preoperative pneumatization.
The extent of re-pneumatization varied widely, even within the same pre-operative pneumatization group. There were 13 cases (12%) that had good pneumatization to the mastoid on pre-operative CT. In this group, the mastoidectomy cavity showed good re-pneumatization in 84% (ten of 13 ears). Even in the poorly pneu-matized group, re-pneumatization to the mastoid was achieved in up to 41~47 percent. In contrast, no aeration in the pre-operative period indicated that the Eustachian tube had provided insufficient ventilation, which prevented even slight improvement (27%, four of 15 cases).
Extent of cholesteatoma and re-pneumatization (Fig. 3)
The extent of re-pneumatization varied widely, even within the same staging group. Stage II showed great improvement, however, there was no statistical difference among three groups. More extensive cholesteatoma did not always suggest poorer post-operative pneumatization.
Fig. 3. Extent of cholesteatoma and re-pneumatization.
Extent of cholesteatoma and hearing, recurrence rate (Table 1)
We evaluated the hearing improvement, residual, and recurrence rate according to the stage. Hearing improvement of each stage was obtained in around 70% of the cases. Residual cholesteatoma occurred in about 10% of ears in every stage. The distribution of recurrence rate was: stage I: 4.7%; stage II: 10.9%; stage III: 20.8%. Although the incidence increased at higher stages, there was no statistical difference among those groups.
Table 1. Extent of cholesteatoma and hearing, recurrence rate.
Conclusions
The extent of cholesteatoma with or without mastoid involvement did not affect the range of re-pneumatization after CWU. A large defect of scutum and posterior canal wall might make it more difficult to achieve mastoid re-pneumatization. A recurrent cholesteatoma resulting from a deep retraction pocket might increase in the same group. On pre-operative CT images, the extent of pneumatization and development of air cells can also be helpful in estimating re- pneumatization after CWU.
References
1.Morimitsu T, et al. Pathogenesis of cholesteatoma based on clinical results of anterior tympanotomy. Auris Nasus Larynx 16(Suppl 1):9–14, 1989
2.Tono T, Miyanaga S, Morimitsu T, Matsumoto I. Computed tomographic evaluation of middle ear aeration following intact canal wall tympanoplasty. Auris Nasus Larynx 14(3):123–130, 1987
Address for correspondence: Keiji Matsuda, Department of otorhinolaryngology, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889–1692 Japan. kmatsuda@med.miyazaki-u.ac.jp
Cholesteatoma and Ear Surgery – An Update, pp. 441–443
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands