LONG-TERM RESULTS AND PROGNOSTIC FACTOR IN SINGLE-STAGE TYMPANOPLASTY
Introduction
Various operative procedures have been developed for the surgical treatment of chronic otitis media with or without cholesteatoma. The principal objective in chronic otitis media with cholesteatoma surgery is the complete eradication of the disease to produce a safe ear and the improvement of hearing. Over the past years, one goal of the complete eradication of the disease has been consistently achieved using the canal-wall-down procedure.1 However, this technique has several problems, such as difficulty with fitting a hearing aid and a higher rate of infection. For this reason, the canal-wall-up procedure is more commonly used.2,3 In reality, the incidence of cholesteatoma recurrence is higher with canal-wall-up procedure than with canal-wall-down procedure. Therefore, staged operation is in heavy usage, and then patients with cholesteatoma must go through operations a number of times.4,5
We use one-stage tympanoplasty with mastoid obliteration, a modified canal-down procedure, for the treatment of otitis media with aeration trouble in the mastoid, while we use a tympanoplasty by transcanal approach for chronic otitis media without aeration trouble in the mastoid. The operation is performed as day surgery.
Otologic surgeons have used a variety of materials for reconstruction of the ossicular chain.6–8 In Japan, autograft replacement is still the most commonly used; biocompatible synthetic materials are very rarely used. However, we have used ceramic prostheses (Type P and Type T) and reported excellent results, including good hearing improvement and low extrusion rates.9
Here we describe the effect of one-staged tympanoplasty with mastoid obliteration and tympanoplasty by transcanal approach using a ceramic prosthesis.
Materials and methods
A retrospective chart review was performed on 516 patients undergoing ossicular chain reconstruction between June 2001 and December 2005. The procedure included one-stage tympanoplasty with mastoid obliteration and tympanoplasty by transcanal approach. Demographic information about these patients is summarized in Table 1.
Table 1. Demografic information
Air-bone gap (ABG) data were obtained by comparing the most recent bone- and air-conduction results. ABG was calculated by the use of four-frequency pure tone averages (500, 1000, 2000, and 3000 Hz) of air and bone conduction from the same test intervals. ‘Successful’ reconstruction was defined as a post-operative PTA-ABG ≤ 20 dB.
Surgical procedure 1
We use one-stage tympanoplasty with mastoid obliteration, a modified canal-wall-down procedure for chronic otitis media with aeration trouble in the mastoid.9 In this procedure, the mastoid cavity is opened by resecting bone of the posterior and superior walls of the external ear canal, after which the antrum and epitympanum are opened. However, the intact canal skin is maintained. After cleaning of the lesions, changes in the ossicular chain, particularly at the long process of the incus and the superstructure of the stapes, are carefully observed. If cholesteatoma includes the whole incus, the incus is removed by separating it from the lesions around the stapes. The tendon of the tensor tympani muscle is also cut. After the opening of the Eustachian tube to the tympanic cavity is confirmed, the eardrum is reconstructed by closing the perforation underlying it with the fascia.
As shown Figure 1, the ossicular chain is reconstructed using a ceramic ossicular prosthesis (P-type or T-type). The ceramic ossicular prosthesis is used after trimming the shaft to the appropriate size. We perform a partial ossicular chain reconstruction using the P-type prosthesis when the superstructure of the stapes can be utilized, while we perform a total chain reconstruction using the T-type prosthesis when the superstructure of the stapes can not be used.
Fig. 1. One-stage tympanoplasty with mastoid obliteration, a modified canal-wall-down procedure. After the ossicular chain was reconstructed using the ceramic ossicular prosthesis (P-type/T-type), the reconstruction of posterior and superior walls of the external ear canal and the obliteration of the mastoid cavity was performed with the bone plate from the mastoid cortical bone.
After reconstruction of the ossicular chain, reconstruction of posterior and superior walls of the external ear canal and obliteration of the mastoid cavity was performed with the bone plate from the mastoid cortical bone. In this surgery, we consider preserving the skin of the external canal and keeping the position of tympanic membrane intact except for the perforation area of the tympanic membrane very important.
Surgical procedure 2
For this procedure we perform a tympanoplasty by transcanal approach for chronic otitis media without aeration trouble in mastoid. An incision is made with a lancet at 12 and 7 o’clock, and the meatal skin is elevated to the level of the fibrous annulus. The bone edge of the posterior canal wall is removed little by little with a chisel until the pyramidal eminence and the stapes tendon are clearly visible. After the annulus is raised, the middle ear is entered. We perform a partial ossicular chain reconstruction using the P-type ceramic prosthesis when the superstructure of the stapes can be used, while we perform a total chain reconstruction using the T-type ceramic prosthesis when the superstructure of the stapes can not be used.
Ninety-three of 100 cases (93%) represented primary surgery in modified canal-wall-down, while 319 of 416 cases (77%) were performed as an unplanned revision surgery in tympanoplasty by transcanal approach (Table 2).
Table 2. Primary Surgery versus Revision Surgery
CWD; Canal Wall Down, TC; Transcanal
In modified canal-wall-down, mean ABG for partial ossicular replacement prostheses was 29.5 dB (SD ± 15.3) post-operatively. Mean ABG for total ossicular replacement prostheses was 38.1 dB (SD ± 12.8). Mean hearing gain in the P-type ceramic group was 10.3 dB (SD ± 7.41). Mean hearing gain for the group of patients following placement of T-type ceramic was 9.3 dB (SD ± 6.83). No patient had a significant acute worsening of bone conduction post-operatively. In tympanoplasty by transcanal approach, post-operative mean ABG for partial ossicular replacement prostheses was 40.4 dB (SD ± 11.9). Mean ABG for total ossicular replacement prostheses was 42.7 dB (SD ± 10.2). Mean hearing gain in the P-type ceramic was 7.8 dB (SD ± 12.8). Mean hearing gain for patients following placement of T-type ceramic was 6.2 dB (SD ± 9.54). No patient had a significant acute worsening of bone conduction post-operatively.
In the modified canal-wall-down group using P-type ceramic, 8.3% of the patients had a post-operative ABG of less than 10 dB. In the tympanoplasty by transcanal approach using ceramic P-type 25% of the patients had a post-operative ABG between 11–20 dB, no patients had a post-operative ABG of less than 10 dB. Ten percent of the patients had a post-operative ABG between 11–20 dB. In the modified canal-wall-down group using T-type ceramic, 17% of the patients had a post-operative ABG of less than 10 dB, 50% of the patients had a post-operative ABG between 11–20 dB, In tympanoplasty by transcanal approach, no patients had a post-operative ABG of less than 10 dB, 20% patients had a post-operative ABG of 11–20 dB. We defined success as post-operative air-bone gap of 20 dB or less. A modified canal-wall-down group using P-type and T-type ceramic prosthesis had a 33.3% and 67% success rate (Fig. 2). A tympanoplasty by transcanal approach using P-type and T-type ceramic prostheses had a 10% and 20% success rate.
Fig. 2. Hearing results by operation performed. A modified canal-wall-down group with P-type ceramic prostheses and the group with T-type ceramic prostheses had a 33.3% and 67% success rate, resp. A tympanoplasty by transcanal approach using P-type and T-type ceramic prostheses had a 10% and 20% success rate, resp.
We have used one-stage tympanoplasty with mastoid obliteration as a modified canal-wall-down procedure for chronic otitis media with aeration trouble in the mastoid.9 The major advantage of the canal-wall-down procedure is that the surgical area is visible through a microscope. We maintain the intact external canal skin and fill the cavity formed by the removal of the bone of the external ear canal with the patient’s own bone fragments obtained from the temporal bone, even though we remove the external ear canal bones and the mastoid cavity. After that, our procedure makes it easy to remove cholesteatoma and granulation, reduces the risk of infection, and prevents perforation of the tympanic membrane. Our results show that air-bone gaps could be reduced to 20 dB or less in 33.3% of the patients with P-type ceramic prosthesis and 67% of the patients with T-type ceramic prosthesis. In this study, we confirmed that the total ossicular reconstruction using a T-type ceramic prosthesis was satisfactory for one-stage tympanoplasty with mastoid obliteration. In fact, we broke down the disadvantage of the canal-wall-down procedure.
We also performed tympanoplasty by transcanal approach for chronic otitis media without aeration trouble in the mastoid. We reported a success rate of 10% for the P-type ceramic prosthesis and 20% for the T-type ceramic prosthesis in tympanoplasty by transcanal approach. In fact, the patients requiring tympanoplasty by transcanal approach had significantly worse results than those with one-stage tympanoplasty with mastoid obliteration. In this study, we considered that patients undergoing a tympanoplasty by transcanal approach had more severe disease including tympanosclerosis than those requiring one-stage tympanoplasty with mastoid obliteration. In addition, our results showed that the hearing results tended to be worse in unplanned revision surgery. Therefore, it is unfair to draw the conclusion that a modified canal-wall-down procedure has better hearing results than the transcanal approach. Our observation is that unsuccessful cases might not have a secure attachment to the stapes footplate because of not allowing tissue integrations. Therefore, we hope that a variety of materials for reconstruction of the ossicular chain will be used in the near future in Japan as well.
We confirmed there was a trend for a better air-bone gap when the middle ear was well aerated and the Eustachian tube functioned well. Conversely, insufficient middle-ear spaces due to post-operative Eustachian tube dysfunction was observed in several unsuccessful cases examined by post-operative Cone Beam CT scanning. We considered that the condition of the pre-operative aeration of the middle ear and the Eustachian-tube function would become an important indicator of post-operative results.
Conclusion
In conclusion, we confirmed the decade-long efficacy in the single-stage tympanoplasty. Especially the total ossicular reconstruction using ceramic T-type was satisfactory for one-stage tympanoplasty with mastoid obliteration. It is important to apply a single-stage tympanoplasty with mastoid obliteration and a tympanoplasty by a transcanal approach for the treatment of chronic otitis media selectively. We considered that the preoperative important prognostic factors in the single-stage tympanoplasty would be the following two points: the condition of the pre-operative aeration of the middle ear and the Eustachian-tube function.
References
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Address for correspondence: Ken Hayashi, ken.hayashi@jcom.home.ne.jp
Cholesteatoma and Ear Surgery – An Update, pp. 455–458
Edited by Haruo Takahashi
2013 © Kugler Publications, Amsterdam, The Netherlands