BMC Ear, Nose and Throat Disorders

Background: To evaluate the long-term surgical outcome(s) in patients who have undergone canal-wall-down operation with mastoid and epitympanic obliteration using autologous cortical bone chips, bone pate and meatally-based musculoperiosteal flap technique. Method: Retrospective evaluation of seventy patients operated during 1986–1991 due to a cholesteatoma. An otomicroscopy was performed to evaluate the postoperative outer ear canal configuration with a modified Likert scale (1 – 4). The outer ear canal physical volume was assessed by tympanometry. The hearing outcome and a patient-filled questionnaire were also analyzed. Results: The posterior wall results were 1.8 (± 0.9 SD) and the attic region 1.8 (± 0.9 SD) (ns., p > 0.05). These values show either no cavity formation or minor formation of a cavity, with a good functional result. The mean volume of the operated ear canal was 1.7 (± 0.5 SD) ml. The volume of the contralateral ear canal was 1.2 (± 0.3 SD) ml (*** p < 0.0001). A comparison of the current mean ABG to the preoperative mean ABG and to the ABG at one-year postoperatively, 5-years postoperatively or 10-years postoperatively showed no statistical significance (p > 0.05). Conclusion: ABG does not significantly change in the long-term. The configuration of the cavity tends to change, however, the obliteration material is stable in the long-term and clinically significant cavitation rarely occurs. Background Canal-wall-down (CWD) tympanomastoidectomy is a well established method in surgery due to cholesteatoma [1]. It provides a good intraoperative exposure and an easy postoperative monitoring. The size of the surgical cavity can be diminished with obliteration to create a small cavity that is self-cleaning and easily maintained [2]. Several authors have demonstrated the usefulness of mastoid obliteration technique and considered it a safe method to diminish a surgical cavity in CWD surgery [3-7]. However, there are only a few studies that have evaluated the configuration of the cavity and the durability of the obliteration material itself in the long-term [6,8-10]. Published: 29 July 2008 BMC Ear, Nose and Throat Disorders 2008, 8:4 doi:10.1186/1472-6815-8-4 Received: 31 January 2008 Accepted: 29 July 2008 This article is available from: http://www.biomedcentral.com/1472-6815/8/4 © 2008 Abdel-Rahman et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Page 1 of 7 (page number not for citation purposes) BMC Ear, Nose and Throat Disorders 2008, 8:4 http://www.biomedcentral.com/1472-6815/8/4 CWD surgery creates a large open cavity, with several possible problems [11]. Both autologous and synthetic materials have been used for obliteration [3,12-14]. In our clinic, autologous cortical bone chips and pate, a meatally based musculoperiosteal flap ("Palva flap"), and temporal fascia are mainly used. The CWD tympanomastoidectomy with this obliteration method has been well characterized [15,16]. We have studied the long term condition of ears that underwent CWD mastoidectomy with mastoid and epitympanic obliteration using autogenous bone chips, bone pate and a musculoperiosteal flap. All the patients that participated in the study were followed at least for 15 years. Clinical experience suggests that the configuration of the cavity changes during the long-term follow-up. Parts of the cavities tend to enlarge and cavities that are difficult to treat occur [17]. We have measured the volumes of the reconstructed ear canals, and evaluated the configuration of a possible cavity and problems caused by that. Methods Patients Between the years 1986 – 1991, a series of 133 CWD tympanomastoidectomies, due to a cholesteatoma, were performed. A musculoperiosteal flap ("Palva flap") was used with autogenous bone for obliteration and reconstruction, by experienced otosurgeons at the Department of Otorhinolaryngology, University of Helsinki. The autogenous cortical bone chips (approximate size 0.5 – 1 cm2), and cortical bone pate were taken from the temporal bone, above the mastoid. The mastoid cavity and epitympanum were filled with these bone chips and bone pate. The obliterated cavity was lined with a piece of temporal fascia and with the musculoperiosteal flap. The flap was not fixed. The ossicular chain was reconstructed either during the analyzed CWD surgery with obliteration or in a later tympanoplasty with autologous ossicular bone or autologous cortical bone. Meatoplasty was not performed routinely. The ear was packed and at the one week followup, the packing was removed. All these patients were invited to the study and were sent an informed consent. Of the 94 patients willing to participate, 70 took part in the study. The patient data, operative details and audiological evaluations were collected retrospectively and analyzed. Ethical consideration The design of this study was proved by the local ethical committee at the Department of Otorhinolaryngology, University of Helsinki. All these patients gave their written informed consent to participate in the study. Otological and audiological examination An otomicroscopy and a tympanometry were performed. In addition, the diameter of the entrance of the outer ear canal was measured with the aid of an ear speculum (6 mm, 8 mm, 10 mm or more). The formation of the cavity in the outer ear canal and in the attic region was evaluated with a modified Likert scale (1 = no cavity formation; 2 = minor formation of a cavity, with a good functional result; 3 = moderate cavity formation, crusting; 4 = major cavity formation, crusting, cholesteatomatic growth in the cavity) by four otosurgeons. Pure-tone audiometry thresholds (0.5, 1, 2 and 4 kHz PTA) via air(AC) and boneconduction (BC) were determined and the air-bone gap (ABG) was calculated. The patients filled in a questionnaire and the data of the questionnaires were analyzed with PrismStat (GraphPad Software Inc., San Diego, USA) (Appendix 1). In the questionnaire the patients were asked the frequency of mastoid debridements and whether the ear had been dry or had it discharged since the surgery. Also problems with the use of hearing aids were evaluated. The t-test was used for statistical analysis (* p < 0.05). Results Patient population In our study there was a male preponderance, 48 males versus 22 females participated. The mean age of the patients at the operation was 40 (± 13 SD) years (range from 7 to 66 years) and at the time of evaluation was 59 (± 13 SD) years (median 60 years) with a mean follow-up period 18 (± 1.5 SD) years (median 18 years). Twenty patients had been previously (before 1986–1991 period) operated due to a cholesteatoma (Table 1). Of those patients, three had been operated three times and one patient operated twice. Nearly all the previous operations had been CWD operations, without obliteration or reconstruction of the attic. Of the patients we evaluated between 1986 and 1991 all were aimed to be single stage surgeries. During the analyzed CWD surgery, six patients had a meatoplasty. After the CWD surgery, 21 (30%) had a second operation to the evaluated operated ear (Table 2). One patient was operated twice and one three times. Six patients were operated due to a recurrent cholestTable 1: Operations to the studied ear prior the evaluated CWD surgery Type of surgery Number of surgeries CWD operation, without obliteration 19 (27%) Simple mastoidectomy 4 (6%) CWU operation 3 (4%) Atticotomy 1 (1%) The type and number of ear surgeries to the analyzed ear prior to the analyzed operation (20 patients). Page 2 of 7 (page number not for citation purposes) BMC Ear, Nose and Throat Disorders 2008, 8:4 http://www.biomedcentral.com/1472-6815/8/4 eatoma (9%). No residual cholesteatomas were found in our material. Otomicroscopy and volume of the cavity In 32 patients we had to use a 6 mm ear speculum. In 29 patients it was possible to use 8 mm ear speculum and only in four cases a 10 mm speculum or larger was used. The size and configuration of the ear canal and/or cavity were estimated. The formation of a cavity in the operated ear was evaluated with an otomicroscope (modified Likert scale, 1 – 4). Most of the operated ears showed a good functional result. The posterior wall of the ear canal and the attic region were analyzed separately. The posterior wall results were 1.8 (± 0.9 SD) and the attic region 1.8 (± 0.9 SD) (ns. p > 0.05) (Table 3). One tympanic membrane perforation was seen. An aerated tympanum was found in 52 patients and an adhesive tympanum was found in 18 patients. The mean volume of the operated ear canal was 1.7 (± 0.5 SD) ml (n = 70). The volume of the contralateral ear canal was 1.2 (± 0.3 SD) ml (n = 59)(*** p < 0.0001). Audiological data The mean AC, BC and ABG values (value ± SD) at different time points are shown in Table 4. A significant difference could be seen between the current mean AC values compared to all other time points (pre-operative, p = 0.002; 1year, p = 0.001; 5-years, p = 0.004; 10-years, 0.004). Also the current mean BC values were significantly different compared to all the other time points (pre-operative, p < 0.001; 1-year, p < 0.001; 5-years, p = 0.01; 10-years, p < 0.001). However, no significant differences could be seen between the current mean ABG and other time points (pre-operative, p = 0.9; 1-year, p = 0.7; 5-years, p = 0.09; 10-years, 0.6). Twenty patients (29%) had an excellent (0–10 dB) or a good (11–20 dB) gap closure one-year after the evaluated surgery. Currently 25 patients (36%) have an excellent or good gap closure in the operated ear (Table 5). Questionnaire The need for debridement of the cavity was evaluated. Currently, 35 patients (50%) had no need for debridement of the cavity. The need for debridement diminished in the long run (Figure 1). Twenty-nine patients (40%) were hearing aid users. Twenty-two of these (76%) were using a hearing aid in the operated side or in both sides. Sixteen of these patients (73%) were comfortable using the hearing aid in the operated ear. On the other hand, five patients had recurrent problems and four patients were unable to wear the aid in the operated ear. Typical problems which these patients were encountering: recurrent infection of the cavity due to hearing aid use (7 patients), fitting problems (5 patients), poor hearing level (6 patients) or combination of these. Discussion A total of 133 patients underwent CWD surgery with complete epitympanic and mastoid obliteration 18 (± 1.5 SD) years ago at our department. Of these, 94 patients were willing to participate and 70 (53%) took part in the study. The data of patients that gave their written informed consent but did not actually participate, were not included. Dense cortical bone chips, collected from the mastoid bone, and cortical bone pate were used for the obliteration of the surgical cavity. A meatally based musculoperiosteal flap was raised when CWD surgery was anticipated. We were especially interested in the stability of the obliteration material that was used. The musculoperiosteal flap atrophies postoperatively, but it often leaves a smooth lining for the cavity [15]. Reconstructed canal walls and reconstructed epitympanic cavities tend to enlarge postoperatively [2]. Sometimes these pockets are deep and may cause cholesteatomatic growth in the cavity. Our results show that the mastoid obliteration with autogenous cortical bone, mainly cortical bone chips, is an efficient and long lasting way to diminish the surgical cavity. Most of the cavities were small and predominantly trouble free. The meatally based musculoperiostel flap will provide a smooth surface for the cavity and deep pockets with cholesteatomatic growth are rare. We Table 2: Operations to the studied ear after the evaluated CWD surgery Type of surgery Number of surgeries Meatoplasty 9 (13%) Myringoplasty 2 (3%) Tympanoplasty 7 (10%) Re-radical operation 6 (9%) The type and number of ear surgeries of patients that had revision surgeries to the analyzed ear after the analyzed operation (21 patients). Table 3: Posterior wall and attic reconstruction