RECONSTRUCTION OF BONY EAR CANAL WALL IN SURGERY FOR CHOLESTEATOMA
Introduction
In surgery for eradication of middle-ear cholesteatoma, a clear and unobstructed view of the attic or the mastoid antrum is necessary. In order to obtain proper exposure, the posterior superior ear canal wall needs to be removed (canal-wall-down mastoidectomy). In the following cohort of patients, after removal of the ear canal wall, the bony ear canal wall was reconstructed with collagen sponge, autologous bone chips and bone paste in our clinic. The aim of this technique was the reconstruction of the hard ear canal wall and the regeneration of the aerated mastoid cavity.
The status of the reconstructed ear canal wall and aeration of the post-operative mastoid cavity were then investigated.
Materials and methods
Our study included 58 ears of patients with middle-ear cholesteatoma who underwent initial surgery (staged tympanoplasty) in our clinic between April 2002 and March 2012. The patients’ age ranged from four to 67 years, and the cohort included 39 male and 19 female patients.
In all ears, a cholesteatoma was eradicated after removal of the ear canal wall at the first stage operation of staged tympanoplasty (Fig. 1a). The bony ear canal wall was then reconstructed with a collagen sponge, autologous bone chips and bone paste. First, a collagen sponge and autologous bone chips were set in the original position of the canal wall (Fig. 1b). Bone paste was placed over the bone chips in order to smoothen the surface of the reconstructed bony canal wall (Fig. 1c). The second-stage operation was performed about one year after the reconstruction of the ear canal wall at the first stage operation.
At the time of the second-stage operation, the status of the reconstructed ear canal wall was classified into three groups based on wall formation: (1) good formation; (2) displaced backward formation; (3) lost formation. In group 1, bone chips and bone paste were fused with the bone of the canal wall, and the bony canal wall was reconstructed well (Fig. 2a). In group 2, bone chips and bone paste were fused to each other, but they were displaced posteriorly (Fig. 2b). In group 3, bone chips and bone paste were partially or totally lost (Fig. 2c).
The aeration of the post-operative mastoid cavity at the time of the second operation was also classified into three groups: (I) totally aerated; (II) partially aerated; (III) non-aerated. In group I, the post-operative mastoid cavity was almost totally aerated. In group II, the post-operative mastoid cavity was aerated mainly in the epitympanic portion. In group III, the mastoid cavity was not aerated at all post-operatively.
Fig. 1. The technique for reconstruction of the ear canal wall. a. Cholesteatoma has already been eradicated after removal of the ear canal wall (arrow). *The skin of the posterior wall of the external ear canal. b. A collagen sponge (arrow) and autologous bone chips were set in the original position of the canal wall. c. Bone paste (arrow) was placed over the bone chips.
Fig. 2. The status of the reconstructed ear canal wall. a. Good formation: Bone chips and bone paste were fused with the bone of the canal wall, and the bony canal wall was reconstructed with an excellent outcome. b. Displaced backward formation: Bone chips and bone paste were fused to each other, but they showed posterior displacement (arrow). c. Lost formation: Bone chips and bone paste were partially or totally lost (arrow).
Results
Forty-nine (84%) of the 58 ears were classified in group 1. In these ears, the formation of the external ear canal was almost normal. The formation was classified as group 2 in three ears (5%) and as group 3 in six ears (11%). In group 2, the formation of the external ear canal was slightly or moderately wide. In group 3, a retraction pocket recurred in three ears and cholesteatoma recurred in one ear.
Fig. 3. The aeration of the mastoid cavity according to age group. The mastoid cavity was aerated more often in younger subjects compared to older subjects, except in those under ten years of age. The mastoid cavity was totally aerated (closed rectangle), partially aerated (rectangle with oblique line), and non-aerated (open rectangle).
The post-operative mastoid cavity was totally aerated in 25 ears (43%), partially aerated in 12 ears (21%), and not aerated in 21 ears (36%). Figure 3 shows the relationship between the aeration of the post-operative mastoid cavity and the age group. The post-operative mastoid cavity was predominantly aerated in those aged between ten and 30 years, but among patients over 40 years of age, it was not aerated in about half of the ears. The mastoid cavity was aerated in nine out of the 15 ears of those under ten years of age. The mastoid cavity was aerated more often in younger subjects, except in those under ten years of age, compared to older subjects.
Residual cholesteatoma was detected in 18 out of 58 ears (31%). In those under ten years of age, residual cholesteatoma was detected in eight out of 15 ears (53%), while it was detected in ten out of 43 ears (32%) in those over ten years of age.
Discussion
Canal-wall-down mastoidectomy is a superior procedure for the complete eradication of middle-ear choles-teatoma. However, the disadvantages of the open cavity are the necessity of periodical intervention and the possibility of infection (cavity problem). To solve these problems, after removal of posterior ear canal wall, reconstruction of ear canal wall by artificial materials such as titanium1,2 or hydroxyapatite3 have been reported in recent years. For restoration of the bony ear canal wall and aeration of the post-operative mastoid cavity, the posterior canal walls were reconstructed by autologous bone chips and bone paste in our clinic.
As a result, bony ear canal walls were well reconstructed and had excellent outcomes. When added together, the 84% ‘good formation’ and 5% ‘displaced backward formation’ groups yielded a clinically acceptable external ear canal in 89% of all reconstructions. In addition, 64% of the post-operative mastoid cavities were aerated. Because of the tissue regenerative ability and the short period of infection, it was thought that the post-operative mastoid cavity was aerated more often in younger subjects. However, in subjects under ten years of age, the aeration of the mastoid cavity was negatively influenced by the Eustachian-tube function.
This technique is useful for the elimination of cholesteatomas and generally yields good post-operative states of the ear canal wall and mastoid cavity.
Bony canal walls were reconstructed well in 49 out of 58 ears by our technique using autologous bone chips and bone paste. The post-operative mastoid cavity was aerated in 37 out of 58 ears. The mastoid cavity was aerated more often in younger subjects than in older subjects (except in those under ten years of age). This technique is useful for the elimination of cholesteatomas and generally yields good post-operative states of the ear canal wall and mastoid cavity.
References
1.Black B. Use of titanium in repair of external auditory canal defects. Otol Neurotol 30(7):930–935, 2009
2.Deveze A, Rameh C, Puchol MS, Lafont B, Lavieille JP, Magnan J. Rehabilitation of canal wall down mastoidectomy using a titanium ear canal implant. Otol Neurotol 31(2):220–224, 2010
3.Zanetti D, Nassif N, Antonelli AR. Surgical repair of bone defects of the ear canal wall with flexible hydroxyapatite sheets: a pilot study. Otol Neurotol 22(6):745–753, 2001
Address for correspondence: Makito Tanabe, Yamamoto Ear Surgicenter, 2–14-13, Yayoi-cho, Izumi city, Osaka 594–0061, Japan. mactanabe@ear-nose.net
Cholesteatoma and Ear Surgery – An Update, pp. 345–348
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands