Otology & Neurotology 35:981Y988 Ó 2014, Otology & Neurotology, Inc.
Chronic Otitis Media With Cholesteatoma With Canal Fistula and Bone Conduction Threshold After Tympanoplasty With Mastoidectomy Tadashi Kitahara, Takefumi Kamakura, Yumi Ohta, Tetsuo Morihana, Arata Horii, Atsuhiko Uno, Takao Imai, Yasuo Mishiro, and Hidenori Inohara Department of OtolaryngologyYHead and Neck Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan
Objective: To understand the third mobile window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: According to the intraoperative classification of Dornhoffer and Milewski, we focused especially on Type IIa (anatomic bony fistula with no perilymph leak). We checked the bone conduction threshold at least 3 times: just before, just after, and 6 months after surgery in 20 ears with Type IIa lateral semicircular canal fistula. Intervention: Tympanoplasty with mastoidectomy. Main Outcome Measure: Bone conduction thresholds before and after tympanoplasty with mastoidectomy. Results: Compared with the preoperative bone conduction threshold, 6 cases were better, 12 cases were unchanged, and
2 cases were worse within the first postoperative week. Finally, 1 case was better, 15 cases were unchanged, and 4 cases were worse at the sixth postoperative month. Patients with a better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms. Postoperative spontaneous nystagmus had a tendency to be observed in patients with a worse bone conduction threshold in the high-tone frequencies. Conclusion: The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the third mobile window theory. The worse bone conduction threshold in high-tone frequencies with spontaneous nystagmus after surgery might indicate inner ear damage. Key Words: Bone conduction thresholdVCholesteatomaVFistula symptomVLow-tone airbone gapVThird mobile window theoryVTympanoplasty with mastoidectomy. Otol Neurotol 35:981Y988, 2014.
The third mobile window theory was first proposed by Minor et al. in 2003 (1) and later confirmed in a human temporal bone study of Chien et al. in 2007 (2). Patients with enlarged vestibular aqueduct syndrome (EVA) and those with superior semicircular canal deficiency syndrome (SSCD) reduce the sound pressure coming through the oval window, apparently impairing the air conduction threshold similar to a stiffness curve. By comparison, EVA and SSCD reduce the sound pressure at the scala
vestibuli and widen the differences in sound compliance between the scala vestibuli and scala tympani, resulting in apparent bone conduction threshold improvement. Thus, apparently impaired air conduction and improved bone conduction cause low-tone air-bone gaps (ABGs) in these patients. An enlarged vestibular aqueduct and superior canal deficiency are supposed to act as the third mobile inner ear windows (3Y5). We recently reported that low-tone ABGs were observed after endolymphatic sac surgery for Me´nie`re’s disease (6) and after canal occlusion surgery for benign paroxysmal positional vertigo (7). These postoperative low-tone ABGs suggest stability secondary to adequate bone resection around the endolymphatic sac in the chronic stage of endolymphatic sac surgery, as in EVA, and instability secondary to the occlusion area on the semicircular canal in the acute stage of canal occlusion surgery, as in SSCD.
Address correspondence and reprint requests to Tadashi Kitahara, M.D., Ph.D., Department of OtolaryngologyYHead and Neck Surgery, Osaka University, Graduate School of Medicine, 2-2 Yamada-oka, Suita-city, Osaka 565-0871, Japan; E-mail: [email protected] This study was supported in part by a Health Science Research Grant for Specific Disease from the Ministry of Health, Labour and Welfare, Japan (2011Y2013). The authors disclose no conflicts of interest.
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Copyright © 2014 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
M M F F M M F M F F M F M F F M F F F M
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
28 41 44 51 68 70 24 48 65 70 76 22 43 40 53 62 54 68 54 75
Age
R L R R R R L L L R R L R L L L R L R R
L/R
pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf
Type
lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc
Lesion
IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa
Stage
1 1 2 2 2 3 1 1 2 2 3 1 1 2 2 3 1 2 2 3
BCHL
Sympt 1 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 1 1
Pre
Fistel
0 0 0 0 0 0 0 0 0 0 1 (pn) 0 0 0 0 1 (pn) 0 1 (sn) 0 1 (sn)
Nyst
BCHL (versus pre) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht)
Post-1 wk
Post-1 wk
Nc Wor (lt) Wor (lt) Wor (lt) Wor (lt) Wor (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht) Nc Nc
BCHL (versus 1 wk)
Post-6 mo
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1(sn)
Nyst
Post-6 mo
Bet (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht) Wor (lt) Wor (ht)
BCHL (versus pre)
Final results
Raw data for all 20 cholesteatoma cases with type IIa of the lateral semicircular canal fistula
f f f f f+b f no no f f f f+b f+b f+b f+b f+b f f f+b f+b
Material
Closure
cwu cwu cwu cwu cwd cwd cwu cwu cwu cwu cwd cwu cwu cwu cwu cwd cwu cwd cwd cwd
Cwu/cwd
2 2 2 2 1 1 2 2 1 1 1 2 2 2 2 1 2 1 2 1
1 or 2
The raw data included sex (m/f), age at surgery (age: years), laterality (l/r), type of cholesteatoma (pf: pars flaccida), lesion of fistula (lscc: lateral semicircular canal), stage of fistula (IIa: classification of Dornhoffer and Milewski IIa), preoperative fistula symptoms (fistel sympt: 0/1), averaged preoperative bone conductive hearing level at 0.5 to 2 kHz (preBCHL; 1: G20dB; 2: 20GG;60dB; 3: 60GG90dB; 4: 90dBG), bone conductive hearing results of postoperative 1 week compared with pre (post-1w BCHL(versus pre); Bet: better; Nc: no change; Wor: worse; lt: low-tone; ht: high-tone), nystagmus of postoperative 1 week (post-1w nyst: 0/1), sn: spontaneous nystagmus, pn: positional nystagmus, final bone conductive hearing results at postoperative 6 months compared with pre (final results BCHL(versus pre)), materials of fistula closure (closure material; f: fascia; b: bone chip), canal wall up/canal wall down (cwu/cwd), 1-staged/2-staged (1 or 2).
M/F
No
TABLE 1.
982 T. KITAHARA ET AL.
Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD
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In the present study, to understand the third mobile inner ear window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula.
the size factor in the present study. Retrospective evaluation of the operation records revealed only information regarding whether the cholesteatoma contacted the fistula. It is also difficult to understand the detailed relationship between a cholesteatoma and fistula, resulting in exclusion of the location factor in the present study.
MATERIALS AND METHODS
At our hospitals, 2-staged surgery (2 in Table 1) was generally performed in patients with chronic otitis media with cholesteatoma to avoid residual recurrence (9,10). Only cases with small lesions, elderly patients, and individuals with systemic comorbidities or with canal wall-down surgery (cwd in Table 1) underwent 1-staged tympanoplasty with mastoidectomy (1 in Table 1). Canal wall-up surgery (cwu in Table 1) was generally adopted in patients with chronic otitis media with cholesteatoma to avoid retraction of epithelial migration (9,10). Only cases with developed lesions underwent canal wall down tympanoplasty with mastoidectomy. Finally, canal fistulas were generally resurfaced with fascia (f in Table 1) and/or bone chips (b in Table 1) to protect the inner ear (11,12). Different types of materials such as fibrin glue and gelatin sponges were used to maintain the reconstruction in place. Those patients with cholesteatoma tracking inside the lateral semicircular canal lumen did not have the matrix removed and remained with the canal exposed in the mastoid cavity (not in Table 1).
The present study was approved by the ethics committee of Osaka University Hospital and Osaka Rosai Hospital. In the present study, the analysis of otologic and neurotologic data were permitted by individual patients.
Patients We performed 30 tympanoplasty with mastoidectomy surgeries for chronic otitis media with cholesteatoma with inner ear fistula at Osaka University Hospital and Osaka Rosai Hospital between April 1996 and September 2012. According to the intraoperative classification of Dornhoffer and Milewski (8), the 30 cholesteatoma cases were divided into Type I (n = 2, perilymphatic membrane covered with bone; i.e., blue line only), Type IIa (n = 21, perilymphatic membrane exposed but intact), Type IIb (n = 4, perilymphatic membrane exposed with perilymph leak), and Type III (n = 3, perilymphatic membrane eroded onto organs). We focused especially on Type IIa, the anatomic bony fistula with no perilymph leak and excluded cases of Types I, IIb, and III. Finally, we checked the bone conduction threshold at least 3 times: just before, just after (1 week postoperatively), and in the long-term postoperative period (6 months postoperatively) after surgery for 20 ears with Type IIa lateral semicircular canal fistula. All 20 ears involved the pars flaccida type of cholesteatoma (pf in Table 1) with no fistula other than Type IIa fistula (IIa in Table 1) of the lateral semicircular canal (lscc in Table 1), as shown in Table 1. It is difficult to measure the size of a Type IIa fistula, which resulted in exclusion of
Surgery
Examinations The bone conduction threshold was measured by a pure-tone audiometer and evaluated based on the 3-tone average formulated by (a + b + c) / 3 (a, b, and c are hearing levels at 0.5, 1, and 2 kHz as usual (no abbreviation in Table 1), at 0.25, 0.5, and 1 kHz for low-tone (lt in Table 1), and at 1, 2, and 4 kHz for high-tone (ht in Table 1)). Differences of more than 10 dB in hearing levels before and after surgery were regarded as ‘‘better’’ (Bet in Table 1), less
FIG. 1. Bone conduction threshold results in cases with canal fistula after tympanoplasty with mastoidectomy. In comparison with the preoperative bone conduction threshold, 6 cases were better (Bet@post-1w: 30.0%), 12 cases were no changed (Nc@post-1w: 60.0%), and 2 cases were worse (Wor@post-1w: 10.0%) within the postoperative one week. Finally, 1 case was better (Bet@post-6m: 5.0%), 5 and 15 cases were not changed (Nc@post-6m: 75.0%), and 4 cases were worse (Wor@post-6m: 20.0%) at the postoperative 6 months. ° 19 mean Case 5 in Figure 3/Table 1 and Case 19 in Figure 4/Table 1, respectively. ° Otology & Neurotology, Vol. 35, No. 6, 2014
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FIG. 2. Preoperative fistula symptoms and bone conduction threshold immediately after tympanoplasty with mastoidectomy. Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure were detected in 13 (65.0%) of 20. Patients with better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms (chi-square test: p = 0.054).
than -10 dB as ‘‘worse’’ (Wor in Table 1), and others as ‘‘no change’’ (Nc in Table 1) (6,7). Nystagmus was judged as significant when at least 3 sequential rhythmical beats were observed using CCD Frenzel goggles. Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure and postoperative vestibular findings were detected according to the above judgment. Vestibular function was measured by a caloric test using an electronystagmogram (ENG). For the caloric test, the external auditory canal was irrigated in turn with 20 ml of 30-C water for 10 seconds. The induced nystagmus was recorded using ENG in a dark, open-eyes situation. Based on the averaged maximum slowphase eye velocity (max-SPEV) in the operated side, max-SPEV after surgery/max-SPEV before surgery was calculated. Values of less than 0.9 were recognized as deterioration and those of greater than 1.1 as improvement in vestibular function (13).
Statistics All data in the present study were treated statistically with the use of SPSS version 14.0 (Chicago, IL, USA). Statistical analysis of the chi-square test was adopted to examine the relationship between preoperative fistula symptoms and postoperative upward shifts in the bone conduction threshold at low-tone frequencies. A p G 0.05 was considered to be significant for the chi-square test.
RESULTS Compared with the preoperative bone conduction threshold, 6 cases were better (30.0%), 12 cases were unchanged (60.0%), and 2 cases were worse (10.0%) within the first postoperative week. Finally, 1 case was better (5.0%), 15 cases were unchanged (75.0%), and 4 cases were worse (20.0%) at the sixth postoperative month (Fig. 1).
Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure were detected in 13 (65.0%) of 20. Patients with a better bone conduction threshold at the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms (chi-square test: p = 0.054) (Fig. 2). Postoperative nystagmus was observed in 4 cases, spontaneous in 2 (10.0%) and positional in 2 (10.0%) immediately after surgery. The former two were quite weak but directed to the nonoperated side. These 2 cases showed a worse bone conduction threshold at the hightone frequencies immediately after surgery. The latter two were geotropic and clinically diagnosed as benign paroxysmal positional vertigo after tympanoplasty with mastoidectomy. Factors of 1/2-staged surgery, canal wall up/down surgery or materials used in canal fistula closure showed no significant correlation with the postoperative bone conduction threshold.
DISCUSSION Six months after tympanoplasty with mastoidectomy surgeries for 20 ears with cholesteatoma with a Type IIa lateral semicircular canal fistula, the bone conduction threshold improved in 5.0%, was unchanged in 75.0%, and worsened in 20.0%. These hearing results agree well with those in previous articles (14Y16), which explained that the bone conduction threshold could be improved fortunately because of the removal of mass affected on the inner ear and deteriorated unfortunately because of the surgical damages. However, we focused on changes in the bone conduction threshold immediately after surgery
Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD in the present study. In comparison with the postoperative long-term hearing results, those just after surgery seemed better as follows: better in 30.0%, unchanged in 60.0%, and worse in 10.0%. Very few reports have demonstrated changes in the bone conduction threshold during the convalescence immediately after tympanoplasty with
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mastoidectomy. The better hearing in these 30.0% of cases just after surgery was limited to the low-tone frequencies of 0.25, 0.5, and 1 kHz. Next, we considered the mechanisms of this unique type of audiographic upward and downward shift of the bone conduction threshold from the point of view of the
FIG. 3. Case 5 with canal fistula showing the postoperative rapid audiographic shift-up and subsequent gradual shift-down of low-tone bone conduction threshold. A, A cholesteatoma case with type IIa of the lateral semicircular canal fistula showed better bone conduction threshold at the postoperative 1 week (po-1w) and then gradual audiographic shift-down to the preoperative level (po-6m). B, CT scan demonstrated cholesteatoma mass and lateral semicircular canal fistula (white arrows) preoperatively (pre: axial, coronal) and fixed materials of temporal fascia and bone chips there (gray arrows) at the postoperative 1 week (po-1w: axial, coronal). C, Caloric-induced nystagmus was observed preoperatively (pre), at the postoperative 1 month (po-1m) and 6 months (po-6m) without any remarkable vestibular functional weakness. The upper graph indicates the trace of eyeball movement and the lower one indicates its velocity. This case is Case 5 in Table 1. Otology & Neurotology, Vol. 35, No. 6, 2014
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third mobile window theory. The inner ear pathology of cholesteatoma with canal fistula in the present study (8) is similar to that of SSCD, which is known to demonstrate low-tone ABGs despite the absence of middle ear disease (1,2,5). The third mobile inner ear window may reduce the sound pressure at the scala vestibuli and widen the
differences in sound compliance between the scala vestibuli and scala tympani, resulting in apparent improvement in the low-tone bone conduction threshold. Of 6 cases of a better bone conduction threshold immediately after surgery (Cases 1Y6 in Table 1), 5 demonstrated a gradual audiographic downward shift to the
FIG. 4. Case 19 with canal fistula showing the postoperative audio-graphic shift-down of low-tone bone conduction threshold. A, A cholesteatoma case with Type IIa of the lateral semicircular canal fistula showed postoperative audiographic shift-down of bone conduction threshold at the postoperative 1 week (p-1stop-1w) and then no recovery to the preoperative level (p-1stop-12m=p-2ndop-6m). B, CT scan demonstrated cholesteatoma mass and lateral semicircular canal fistula (white arrows) preoperatively (pre-1stop: axial) and fixed materials of temporal fascia and bone chips there (gray arrows) at the postoperative 1 week (p-1stop-1w: axial) and 6 months (p-1stop6m=pre-2ndop: axial). C, Caloric-induced nystagmus was observed preoperatively (pre-1stop), at the postoperative 1 month (p-1stop-1m) and 6 months (p-1stop-6m=pre-2ndop) without any remarkable vestibular functional weakness. The upper graph indicates the trace of eyeball movement, and the lower one indicates its velocity. This is Case 19 in Table 1. Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD preoperative level (Cases 2Y6 in Table 1). The detailed data of Case 5 are shown in Figure 3 as a representative 1 of the 5 cases. This gradual downward shift in hearing could not be due to inner ear damage because changes in the bone conduction threshold were limited to the low-tone frequencies and vestibular findings, or symptoms were not observed after tympanoplasty with mastoidectomy. Furthermore, these cases did not show any preoperative fistula symptoms at all. All of these findings suggest that this gradual audiographic downward shift of the bone conduction threshold could have been due to the following mechanisms: removal of the cholesteatoma changed the canal fistula from having poor window mobility to having good mobility, resulting in the postoperative third mobile window effect as a rapid audiographic upward shift of the low-tone bone conduction threshold. Closure of the canal fistula during surgery then gradually diminished the mobile window effect with a subsequent audiographic downward shift of the low-tone bone conduction threshold. Eventually, this kind of postoperative rapid upward shift and gradual downward shift would not be clinically problematic because there were no significant differences between the preoperative and postoperative bone conduction thresholds. The other case may have actually shown improved inner ear function, although neurotologic examinations were not adequately prepared (Case 1 in Table 1). We would like to emphasize the following problematic pattern that a postoperative audiographic downward shift of the bone conduction threshold would occur after tympanoplasty with mastoidectomy and then fixed worse than before surgery (Cases 17Y20 in Table 1). The worse bone conduction threshold at high-tone frequencies with nystagmus directed to the healthy side after surgery indicates the presence of surgery-induced inner ear damage (Cases 18 and 20 in Table 1). On the other hand, the worse bone conduction threshold at the low-tone frequencies after surgery with no nystagmus and no dizzy symptoms indicates the absence of surgery-induced inner ear damage (Cases 17 and 19 in Table 1). The detailed data of Case 19 are shown in Figure 4 as a representative case. Furthermore, these cases showed preoperative fistula symptoms. All of these findings suggest that this postoperative audiographic downward shift of the bone conduction threshold could have been due to the following mechanisms: the canal fistula due to the cholesteatoma had good window mobility before surgery, resulting in the preoperative third mobile window effect as an audiographic upward shift of the low-tone bone conduction threshold. Closure of the canal fistula during surgery then diminished the mobile window effect with a subsequent audiographic downward shift of the low-tone bone conduction threshold. Therefore, it should be noted that postoperative hearing gain could not be better than expected according to the preoperative ABGs. Our study has limitations. The present study was retrospective in nature, and the neurotologic examinations were not adequately prepared. Only patients with Type IIa canal fistulas were enrolled in the present study to exclude inner ear damage through the perilymph leak, and
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the number of these patients was small. It is difficult to measure the size of a Type IIa canal fistula, resulting in exclusion of the size factor in the present analysis. Retrospective evaluation of the operation records only provided information on whether the cholesteatoma contacted the fistula. It is also difficult to understand the detailed relationship between a cholesteatoma and fistula, resulting in exclusion of the location factor in the present analysis. The third mobile window effect could also have influenced the air conduction threshold, but it was quite difficult to evaluate the effect on the air conductive hearing level in cases with middle ear diseases. Further studies are needed to confirm the mechanisms of this phenomenon in cases with cholesteatoma with canal fistula. CONCLUSION We performed tympanoplasty with mastoidectomy surgeries for 20 chronic otitis media with cholesteatoma cases with Type IIa lateral semicircular canal fistula during 1996 to 2012 and observed them at least for 6 months after surgery. (1)There are 2 possible reasons why the bone conduction threshold improved after tympanoplasty with mastoidectomy. One is the improvement in the inner ear function, and the other is the appearance of the third mobile window effect after removal of the cholesteatoma. The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the latter theory. (2)There are 2 possible reasons why the bone conduction threshold became worse after surgery. One is deterioration of the inner ear function, and the other is the disappearance of the third mobile window effect after removal of the cholesteatoma and closure of the fistula. The worse bone conduction threshold at high-tone frequencies with nystagmus after surgery might indicate the former possibility. Acknowledgment: The authors thank Dr. Michiko Shuto, a registered statistician (certificate number: 62720218), for helpful advice on statistical analysis.
REFERENCES 1. Minor LB, Carey JP, Cremer PD, Lustig LR, Streubel SO, Ruckenstein MJ. Dehiscence of bone overlying the superior canal as a cause of apparent conductive hearing loss. Otol Neurotol 2003; 24:270Y8. 2. Chien W, Ravicz ME, Rosowski JJ, Merchant SN. Measurements of human middle- and inner-ear mechanics with dehiscence of the superior semicircular canal. Otol Neurotol 2007;28:250Y7. 3. Nakashima T, Ueda H, Furuhashi A, Sato E, Asahi K, Naganawa S. Air-bone gap and resonant frequency in large vestibular aqueduct syndrome. Am J Otol 2000;21:671Y4. 4. Merchant SN, Nakajima HH, Halpin C, Nadol JB Jr, Lee DJ, Innis WP. Clinical investigation and mechanism of air-bone gaps in large vestibular aqueduct syndrome. Ann Otol Rhinol Laryngol 2007a; 116:532Y41. Otology & Neurotology, Vol. 35, No. 6, 2014
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5. Merchant SN, Rosowski JJ, McKenna MJ. Superior semicircular canal dehiscence mimicking otosclerotic hearing loss. Adv Otorhinolaryngol 2007b;65:137Y45. 6. Kitahara T, Horii A, Mishiro Y, et al. Low-tone air-bone gaps after endolymphatic sac surgery. Auris Nasus Larynx 2011;38:178Y84. 7. Uetsuka S, Kitahara T, Horii A, et al. Transient low-tone air-bone gaps during convalescence immediately after canal plugging surgery for BPPV. Auris Nasus Larynx 2012;39:356Y60. 8. Dornhoffer JL, Milewski C. Management of the open labyrinth. Otolaryngol Head Neck Surg 1995;112:410Y4. 9. Sanna M, Zini C, Scandellari R, Jemmi G. Residual and recurrent cholesteatoma in closed tympanoplasty. Am J Otol 1984;5:277Y82. 10. Yanagihara N, Komori M, Hinohira Y. Total mastoid obliteration in staged canal-up tympanoplasty for cholesteatoma facilitates tympanic aeration. Otol Neurotol 2009;30:766Y70. 11. Palva T, Ramsay H. Treatment of labyrinthine fistula. Arch Otolaryngol Head Neck Surg 1989;115:804Y806.
12. Yamamoto N, Fujimura S, Ogino E, Hiraumi H, Sakamoto T, Ito J. Management of labyrinthine fistulae in Kyoto University Hospital. Acta Otolaryngol Suppl 2010;563:16Y9. 13. Kitahara T, Kubo T, Okumura S, Kitahara M. Effects of endolymphatic sac drainage with steroids for intractable Meniere’s disease: a long-term follow-up and randomized controlled study. Laryngoscope 2008;118:854Y61. 14. Quaranta N, Liuzzi C, Zizzi S, Dicorato A, Quaranta A. Surgical treatment of labyrinthine fistula in cholesteatoma surgery. Otolaryngol Head Neck Surg 2009;140:406Y11. 15. Ikeda R, Kobayashi T, Kawase T, Oshima T, Sato T. Risk factors for deterioration of bone conduction hearing in cases of labyrinthine fistula caused by middle ear cholesteatoma. Ann Otol Rhinol Laryngol 2012;121:162Y7. 16. Moon IS, Kwon MO, Park CY, et al. Surgical management of labyrinthine fistula in chronic otitis media with cholesteatoma. Auris Nasus Larynx 2012;39:261Y4.
Otology & Neurotology, Vol. 35, No. 6, 2014
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Chronic Otitis Media With Cholesteatoma With Canal Fistula and Bone Conduction Threshold After Tympanoplasty With Mastoidectomy Tadashi Kitahara, Takefumi Kamakura, Yumi Ohta, Tetsuo Morihana, Arata Horii, Atsuhiko Uno, Takao Imai, Yasuo Mishiro, and Hidenori Inohara Department of OtolaryngologyYHead and Neck Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan
Objective: To understand the third mobile window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: According to the intraoperative classification of Dornhoffer and Milewski, we focused especially on Type IIa (anatomic bony fistula with no perilymph leak). We checked the bone conduction threshold at least 3 times: just before, just after, and 6 months after surgery in 20 ears with Type IIa lateral semicircular canal fistula. Intervention: Tympanoplasty with mastoidectomy. Main Outcome Measure: Bone conduction thresholds before and after tympanoplasty with mastoidectomy. Results: Compared with the preoperative bone conduction threshold, 6 cases were better, 12 cases were unchanged, and
2 cases were worse within the first postoperative week. Finally, 1 case was better, 15 cases were unchanged, and 4 cases were worse at the sixth postoperative month. Patients with a better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms. Postoperative spontaneous nystagmus had a tendency to be observed in patients with a worse bone conduction threshold in the high-tone frequencies. Conclusion: The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the third mobile window theory. The worse bone conduction threshold in high-tone frequencies with spontaneous nystagmus after surgery might indicate inner ear damage. Key Words: Bone conduction thresholdVCholesteatomaVFistula symptomVLow-tone airbone gapVThird mobile window theoryVTympanoplasty with mastoidectomy. Otol Neurotol 35:981Y988, 2014.
The third mobile window theory was first proposed by Minor et al. in 2003 (1) and later confirmed in a human temporal bone study of Chien et al. in 2007 (2). Patients with enlarged vestibular aqueduct syndrome (EVA) and those with superior semicircular canal deficiency syndrome (SSCD) reduce the sound pressure coming through the oval window, apparently impairing the air conduction threshold similar to a stiffness curve. By comparison, EVA and SSCD reduce the sound pressure at the scala
vestibuli and widen the differences in sound compliance between the scala vestibuli and scala tympani, resulting in apparent bone conduction threshold improvement. Thus, apparently impaired air conduction and improved bone conduction cause low-tone air-bone gaps (ABGs) in these patients. An enlarged vestibular aqueduct and superior canal deficiency are supposed to act as the third mobile inner ear windows (3Y5). We recently reported that low-tone ABGs were observed after endolymphatic sac surgery for Me´nie`re’s disease (6) and after canal occlusion surgery for benign paroxysmal positional vertigo (7). These postoperative low-tone ABGs suggest stability secondary to adequate bone resection around the endolymphatic sac in the chronic stage of endolymphatic sac surgery, as in EVA, and instability secondary to the occlusion area on the semicircular canal in the acute stage of canal occlusion surgery, as in SSCD.
Address correspondence and reprint requests to Tadashi Kitahara, M.D., Ph.D., Department of OtolaryngologyYHead and Neck Surgery, Osaka University, Graduate School of Medicine, 2-2 Yamada-oka, Suita-city, Osaka 565-0871, Japan; E-mail: [email protected] This study was supported in part by a Health Science Research Grant for Specific Disease from the Ministry of Health, Labour and Welfare, Japan (2011Y2013). The authors disclose no conflicts of interest.
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M M F F M M F M F F M F M F F M F F F M
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
28 41 44 51 68 70 24 48 65 70 76 22 43 40 53 62 54 68 54 75
Age
R L R R R R L L L R R L R L L L R L R R
L/R
pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf pf
Type
lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc lscc
Lesion
IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa IIa
Stage
1 1 2 2 2 3 1 1 2 2 3 1 1 2 2 3 1 2 2 3
BCHL
Sympt 1 0 0 0 0 0 1 1 1 0 1 1 1 1 0 1 1 1 1 1
Pre
Fistel
0 0 0 0 0 0 0 0 0 0 1 (pn) 0 0 0 0 1 (pn) 0 1 (sn) 0 1 (sn)
Nyst
BCHL (versus pre) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Bet (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht)
Post-1 wk
Post-1 wk
Nc Wor (lt) Wor (lt) Wor (lt) Wor (lt) Wor (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht) Nc Nc
BCHL (versus 1 wk)
Post-6 mo
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1(sn)
Nyst
Post-6 mo
Bet (lt) Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Nc Wor (lt) Wor (ht) Wor (lt) Wor (ht)
BCHL (versus pre)
Final results
Raw data for all 20 cholesteatoma cases with type IIa of the lateral semicircular canal fistula
f f f f f+b f no no f f f f+b f+b f+b f+b f+b f f f+b f+b
Material
Closure
cwu cwu cwu cwu cwd cwd cwu cwu cwu cwu cwd cwu cwu cwu cwu cwd cwu cwd cwd cwd
Cwu/cwd
2 2 2 2 1 1 2 2 1 1 1 2 2 2 2 1 2 1 2 1
1 or 2
The raw data included sex (m/f), age at surgery (age: years), laterality (l/r), type of cholesteatoma (pf: pars flaccida), lesion of fistula (lscc: lateral semicircular canal), stage of fistula (IIa: classification of Dornhoffer and Milewski IIa), preoperative fistula symptoms (fistel sympt: 0/1), averaged preoperative bone conductive hearing level at 0.5 to 2 kHz (preBCHL; 1: G20dB; 2: 20GG;60dB; 3: 60GG90dB; 4: 90dBG), bone conductive hearing results of postoperative 1 week compared with pre (post-1w BCHL(versus pre); Bet: better; Nc: no change; Wor: worse; lt: low-tone; ht: high-tone), nystagmus of postoperative 1 week (post-1w nyst: 0/1), sn: spontaneous nystagmus, pn: positional nystagmus, final bone conductive hearing results at postoperative 6 months compared with pre (final results BCHL(versus pre)), materials of fistula closure (closure material; f: fascia; b: bone chip), canal wall up/canal wall down (cwu/cwd), 1-staged/2-staged (1 or 2).
M/F
No
TABLE 1.
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Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD
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In the present study, to understand the third mobile inner ear window effect of chronic otitis media with cholesteatoma with inner ear fistula on the bone conduction threshold, we examined changes in the bone conduction audiogram after tympanoplasty with mastoidectomy for chronic otitis media with cholesteatoma with canal fistula.
the size factor in the present study. Retrospective evaluation of the operation records revealed only information regarding whether the cholesteatoma contacted the fistula. It is also difficult to understand the detailed relationship between a cholesteatoma and fistula, resulting in exclusion of the location factor in the present study.
MATERIALS AND METHODS
At our hospitals, 2-staged surgery (2 in Table 1) was generally performed in patients with chronic otitis media with cholesteatoma to avoid residual recurrence (9,10). Only cases with small lesions, elderly patients, and individuals with systemic comorbidities or with canal wall-down surgery (cwd in Table 1) underwent 1-staged tympanoplasty with mastoidectomy (1 in Table 1). Canal wall-up surgery (cwu in Table 1) was generally adopted in patients with chronic otitis media with cholesteatoma to avoid retraction of epithelial migration (9,10). Only cases with developed lesions underwent canal wall down tympanoplasty with mastoidectomy. Finally, canal fistulas were generally resurfaced with fascia (f in Table 1) and/or bone chips (b in Table 1) to protect the inner ear (11,12). Different types of materials such as fibrin glue and gelatin sponges were used to maintain the reconstruction in place. Those patients with cholesteatoma tracking inside the lateral semicircular canal lumen did not have the matrix removed and remained with the canal exposed in the mastoid cavity (not in Table 1).
The present study was approved by the ethics committee of Osaka University Hospital and Osaka Rosai Hospital. In the present study, the analysis of otologic and neurotologic data were permitted by individual patients.
Patients We performed 30 tympanoplasty with mastoidectomy surgeries for chronic otitis media with cholesteatoma with inner ear fistula at Osaka University Hospital and Osaka Rosai Hospital between April 1996 and September 2012. According to the intraoperative classification of Dornhoffer and Milewski (8), the 30 cholesteatoma cases were divided into Type I (n = 2, perilymphatic membrane covered with bone; i.e., blue line only), Type IIa (n = 21, perilymphatic membrane exposed but intact), Type IIb (n = 4, perilymphatic membrane exposed with perilymph leak), and Type III (n = 3, perilymphatic membrane eroded onto organs). We focused especially on Type IIa, the anatomic bony fistula with no perilymph leak and excluded cases of Types I, IIb, and III. Finally, we checked the bone conduction threshold at least 3 times: just before, just after (1 week postoperatively), and in the long-term postoperative period (6 months postoperatively) after surgery for 20 ears with Type IIa lateral semicircular canal fistula. All 20 ears involved the pars flaccida type of cholesteatoma (pf in Table 1) with no fistula other than Type IIa fistula (IIa in Table 1) of the lateral semicircular canal (lscc in Table 1), as shown in Table 1. It is difficult to measure the size of a Type IIa fistula, which resulted in exclusion of
Surgery
Examinations The bone conduction threshold was measured by a pure-tone audiometer and evaluated based on the 3-tone average formulated by (a + b + c) / 3 (a, b, and c are hearing levels at 0.5, 1, and 2 kHz as usual (no abbreviation in Table 1), at 0.25, 0.5, and 1 kHz for low-tone (lt in Table 1), and at 1, 2, and 4 kHz for high-tone (ht in Table 1)). Differences of more than 10 dB in hearing levels before and after surgery were regarded as ‘‘better’’ (Bet in Table 1), less
FIG. 1. Bone conduction threshold results in cases with canal fistula after tympanoplasty with mastoidectomy. In comparison with the preoperative bone conduction threshold, 6 cases were better (Bet@post-1w: 30.0%), 12 cases were no changed (Nc@post-1w: 60.0%), and 2 cases were worse (Wor@post-1w: 10.0%) within the postoperative one week. Finally, 1 case was better (Bet@post-6m: 5.0%), 5 and 15 cases were not changed (Nc@post-6m: 75.0%), and 4 cases were worse (Wor@post-6m: 20.0%) at the postoperative 6 months. ° 19 mean Case 5 in Figure 3/Table 1 and Case 19 in Figure 4/Table 1, respectively. ° Otology & Neurotology, Vol. 35, No. 6, 2014
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FIG. 2. Preoperative fistula symptoms and bone conduction threshold immediately after tympanoplasty with mastoidectomy. Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure were detected in 13 (65.0%) of 20. Patients with better bone conduction threshold in the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms (chi-square test: p = 0.054).
than -10 dB as ‘‘worse’’ (Wor in Table 1), and others as ‘‘no change’’ (Nc in Table 1) (6,7). Nystagmus was judged as significant when at least 3 sequential rhythmical beats were observed using CCD Frenzel goggles. Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure and postoperative vestibular findings were detected according to the above judgment. Vestibular function was measured by a caloric test using an electronystagmogram (ENG). For the caloric test, the external auditory canal was irrigated in turn with 20 ml of 30-C water for 10 seconds. The induced nystagmus was recorded using ENG in a dark, open-eyes situation. Based on the averaged maximum slowphase eye velocity (max-SPEV) in the operated side, max-SPEV after surgery/max-SPEV before surgery was calculated. Values of less than 0.9 were recognized as deterioration and those of greater than 1.1 as improvement in vestibular function (13).
Statistics All data in the present study were treated statistically with the use of SPSS version 14.0 (Chicago, IL, USA). Statistical analysis of the chi-square test was adopted to examine the relationship between preoperative fistula symptoms and postoperative upward shifts in the bone conduction threshold at low-tone frequencies. A p G 0.05 was considered to be significant for the chi-square test.
RESULTS Compared with the preoperative bone conduction threshold, 6 cases were better (30.0%), 12 cases were unchanged (60.0%), and 2 cases were worse (10.0%) within the first postoperative week. Finally, 1 case was better (5.0%), 15 cases were unchanged (75.0%), and 4 cases were worse (20.0%) at the sixth postoperative month (Fig. 1).
Preoperative fistula symptoms of nystagmus with positive/negative middle ear pressure were detected in 13 (65.0%) of 20. Patients with a better bone conduction threshold at the low-tone frequencies immediately after surgery had a tendency to show no preoperative fistula symptoms (chi-square test: p = 0.054) (Fig. 2). Postoperative nystagmus was observed in 4 cases, spontaneous in 2 (10.0%) and positional in 2 (10.0%) immediately after surgery. The former two were quite weak but directed to the nonoperated side. These 2 cases showed a worse bone conduction threshold at the hightone frequencies immediately after surgery. The latter two were geotropic and clinically diagnosed as benign paroxysmal positional vertigo after tympanoplasty with mastoidectomy. Factors of 1/2-staged surgery, canal wall up/down surgery or materials used in canal fistula closure showed no significant correlation with the postoperative bone conduction threshold.
DISCUSSION Six months after tympanoplasty with mastoidectomy surgeries for 20 ears with cholesteatoma with a Type IIa lateral semicircular canal fistula, the bone conduction threshold improved in 5.0%, was unchanged in 75.0%, and worsened in 20.0%. These hearing results agree well with those in previous articles (14Y16), which explained that the bone conduction threshold could be improved fortunately because of the removal of mass affected on the inner ear and deteriorated unfortunately because of the surgical damages. However, we focused on changes in the bone conduction threshold immediately after surgery
Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD in the present study. In comparison with the postoperative long-term hearing results, those just after surgery seemed better as follows: better in 30.0%, unchanged in 60.0%, and worse in 10.0%. Very few reports have demonstrated changes in the bone conduction threshold during the convalescence immediately after tympanoplasty with
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mastoidectomy. The better hearing in these 30.0% of cases just after surgery was limited to the low-tone frequencies of 0.25, 0.5, and 1 kHz. Next, we considered the mechanisms of this unique type of audiographic upward and downward shift of the bone conduction threshold from the point of view of the
FIG. 3. Case 5 with canal fistula showing the postoperative rapid audiographic shift-up and subsequent gradual shift-down of low-tone bone conduction threshold. A, A cholesteatoma case with type IIa of the lateral semicircular canal fistula showed better bone conduction threshold at the postoperative 1 week (po-1w) and then gradual audiographic shift-down to the preoperative level (po-6m). B, CT scan demonstrated cholesteatoma mass and lateral semicircular canal fistula (white arrows) preoperatively (pre: axial, coronal) and fixed materials of temporal fascia and bone chips there (gray arrows) at the postoperative 1 week (po-1w: axial, coronal). C, Caloric-induced nystagmus was observed preoperatively (pre), at the postoperative 1 month (po-1m) and 6 months (po-6m) without any remarkable vestibular functional weakness. The upper graph indicates the trace of eyeball movement and the lower one indicates its velocity. This case is Case 5 in Table 1. Otology & Neurotology, Vol. 35, No. 6, 2014
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third mobile window theory. The inner ear pathology of cholesteatoma with canal fistula in the present study (8) is similar to that of SSCD, which is known to demonstrate low-tone ABGs despite the absence of middle ear disease (1,2,5). The third mobile inner ear window may reduce the sound pressure at the scala vestibuli and widen the
differences in sound compliance between the scala vestibuli and scala tympani, resulting in apparent improvement in the low-tone bone conduction threshold. Of 6 cases of a better bone conduction threshold immediately after surgery (Cases 1Y6 in Table 1), 5 demonstrated a gradual audiographic downward shift to the
FIG. 4. Case 19 with canal fistula showing the postoperative audio-graphic shift-down of low-tone bone conduction threshold. A, A cholesteatoma case with Type IIa of the lateral semicircular canal fistula showed postoperative audiographic shift-down of bone conduction threshold at the postoperative 1 week (p-1stop-1w) and then no recovery to the preoperative level (p-1stop-12m=p-2ndop-6m). B, CT scan demonstrated cholesteatoma mass and lateral semicircular canal fistula (white arrows) preoperatively (pre-1stop: axial) and fixed materials of temporal fascia and bone chips there (gray arrows) at the postoperative 1 week (p-1stop-1w: axial) and 6 months (p-1stop6m=pre-2ndop: axial). C, Caloric-induced nystagmus was observed preoperatively (pre-1stop), at the postoperative 1 month (p-1stop-1m) and 6 months (p-1stop-6m=pre-2ndop) without any remarkable vestibular functional weakness. The upper graph indicates the trace of eyeball movement, and the lower one indicates its velocity. This is Case 19 in Table 1. Otology & Neurotology, Vol. 35, No. 6, 2014
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CANAL FISTULA AND BONE CONDUCTION THRESHOLD preoperative level (Cases 2Y6 in Table 1). The detailed data of Case 5 are shown in Figure 3 as a representative 1 of the 5 cases. This gradual downward shift in hearing could not be due to inner ear damage because changes in the bone conduction threshold were limited to the low-tone frequencies and vestibular findings, or symptoms were not observed after tympanoplasty with mastoidectomy. Furthermore, these cases did not show any preoperative fistula symptoms at all. All of these findings suggest that this gradual audiographic downward shift of the bone conduction threshold could have been due to the following mechanisms: removal of the cholesteatoma changed the canal fistula from having poor window mobility to having good mobility, resulting in the postoperative third mobile window effect as a rapid audiographic upward shift of the low-tone bone conduction threshold. Closure of the canal fistula during surgery then gradually diminished the mobile window effect with a subsequent audiographic downward shift of the low-tone bone conduction threshold. Eventually, this kind of postoperative rapid upward shift and gradual downward shift would not be clinically problematic because there were no significant differences between the preoperative and postoperative bone conduction thresholds. The other case may have actually shown improved inner ear function, although neurotologic examinations were not adequately prepared (Case 1 in Table 1). We would like to emphasize the following problematic pattern that a postoperative audiographic downward shift of the bone conduction threshold would occur after tympanoplasty with mastoidectomy and then fixed worse than before surgery (Cases 17Y20 in Table 1). The worse bone conduction threshold at high-tone frequencies with nystagmus directed to the healthy side after surgery indicates the presence of surgery-induced inner ear damage (Cases 18 and 20 in Table 1). On the other hand, the worse bone conduction threshold at the low-tone frequencies after surgery with no nystagmus and no dizzy symptoms indicates the absence of surgery-induced inner ear damage (Cases 17 and 19 in Table 1). The detailed data of Case 19 are shown in Figure 4 as a representative case. Furthermore, these cases showed preoperative fistula symptoms. All of these findings suggest that this postoperative audiographic downward shift of the bone conduction threshold could have been due to the following mechanisms: the canal fistula due to the cholesteatoma had good window mobility before surgery, resulting in the preoperative third mobile window effect as an audiographic upward shift of the low-tone bone conduction threshold. Closure of the canal fistula during surgery then diminished the mobile window effect with a subsequent audiographic downward shift of the low-tone bone conduction threshold. Therefore, it should be noted that postoperative hearing gain could not be better than expected according to the preoperative ABGs. Our study has limitations. The present study was retrospective in nature, and the neurotologic examinations were not adequately prepared. Only patients with Type IIa canal fistulas were enrolled in the present study to exclude inner ear damage through the perilymph leak, and
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the number of these patients was small. It is difficult to measure the size of a Type IIa canal fistula, resulting in exclusion of the size factor in the present analysis. Retrospective evaluation of the operation records only provided information on whether the cholesteatoma contacted the fistula. It is also difficult to understand the detailed relationship between a cholesteatoma and fistula, resulting in exclusion of the location factor in the present analysis. The third mobile window effect could also have influenced the air conduction threshold, but it was quite difficult to evaluate the effect on the air conductive hearing level in cases with middle ear diseases. Further studies are needed to confirm the mechanisms of this phenomenon in cases with cholesteatoma with canal fistula. CONCLUSION We performed tympanoplasty with mastoidectomy surgeries for 20 chronic otitis media with cholesteatoma cases with Type IIa lateral semicircular canal fistula during 1996 to 2012 and observed them at least for 6 months after surgery. (1)There are 2 possible reasons why the bone conduction threshold improved after tympanoplasty with mastoidectomy. One is the improvement in the inner ear function, and the other is the appearance of the third mobile window effect after removal of the cholesteatoma. The better bone conduction threshold at low-tone frequencies immediately after tympanoplasty with mastoidectomy and no preoperative fistula symptoms might imply the latter theory. (2)There are 2 possible reasons why the bone conduction threshold became worse after surgery. One is deterioration of the inner ear function, and the other is the disappearance of the third mobile window effect after removal of the cholesteatoma and closure of the fistula. The worse bone conduction threshold at high-tone frequencies with nystagmus after surgery might indicate the former possibility. Acknowledgment: The authors thank Dr. Michiko Shuto, a registered statistician (certificate number: 62720218), for helpful advice on statistical analysis.
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