International Journal of Pediatric Otorhinolaryngology (2006) 70, 385—393
www.elsevier.com/locate/ijporl
REVIEW ARTICLE
Pediatric cholesteatoma: A retrospective review§ Scott A. Schraff, Barry Strasnick * Department of Otolaryngology — Head and Neck Surgery, Eastern Virginia Medical School and the Children’s Hospital of the King’s Daughters, Norfolk, VA, USA Received 14 June 2005; received in revised form 11 October 2005; accepted 18 October 2005
KEYWORDS Pediatric cholesteatoma; Intact canal mastoidectomy; Canal wall up mastoidectomy; Canal wall down mastoidectomy; Recurrent cholesteatoma
Summary Objectives: The optimal treatment for pediatric cholesteatoma is controversial. Management decisions including intact canal wall versus open cavity techniques, second look procedures and staging ossicular reconstruction continue to be debated. In an attempt to clarify this issue we conducted an 11-year retrospective analysis of our experience with cholesteatoma presenting in our pediatric population. Study design: Retrospective review of children undergoing surgical intervention for cholesteatoma at a tertiary care pediatric hospital between 1 July 1992 and 1 July 2003 by the senior author. Methods: Comparison of recurrence rates in intact canal wall (ICW) versus canal wall down (CWD) procedures; with analysis of second-look procedures, ossicular chain reconstruction (OCR) and hearing results in the management of pediatric cholesteatoma. Results: Two hundred and sixty-two children with 278 cases of cholesteatoma underwent surgical resection. Of these children, 221 were managed via an ICW approach while the remaining 57 underwent a CWD procedure. The overall recurrence rate in this series was 16%, with 17% in the ICW group and 12% in the CWD group. OCR was performed in 97% of the ICW cases at time of second-look procedure, with 75% undergoing reconstruction with partial ossicular reconstruction prosthesis. The average air-bone gap improvement in these patients was 10.8 dB, with an average hearing improvement of total ossicular reconstruction of 5.8 dB. The average hearing improvement in the CWD group, all managed with cartilage interposition grafts, was 3.7 dB. Conclusions: Management of pediatric cholesteatoma requires a highly individualized approach that takes into account anatomic, clinical and social factors to determine the most successful surgical treatment paradigm. # 2005 Published by Elsevier Ireland Ltd.
§
For presentation at the podium of the 2005 Southern Section Meeting of The Triological Society, Miami, FL, 13—15 January. * Corresponding author at: Department of Otolaryngology — Head and Neck Surgery, Eastern Virginia Medical School, 825 Fairfax Avenue, Suite 510, Norfolk, VA 23507-1914, USA. Tel.: +1 757 675 2582; fax: +1 757 446 5968. E-mail address:
[email protected] (B. Strasnick). 0165-5876/$ — see front matter # 2005 Published by Elsevier Ireland Ltd. doi:10.1016/j.ijporl.2005.10.006
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Contents 1. 2. 3. 4. 5.
Introduction . . . . . . . Materials and methods Results . . . . . . . . . . Discussion . . . . . . . . Conclusions . . . . . . . References . . . . . . . .
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1. Introduction Although it has been well studied, there is no clear consensus regarding the surgical management of cholesteatoma in children. The three most popular surgical techniques in the pediatric population are transcanal tympanoplasty, intact canal wall tympanomastoidectomy (ICW) and canal wall-down tympanomastoidectomy (CWD). Each has its own inherent strengths and weaknesses, and the technique used is based on location and extent of disease at time of surgery, as well as surgeon preference and experience. Transcanal tympanoplasty is probably the least commonly performed primary procedure due to exposure limitations. It is, however, used for second-look procedures approximately 6—12 months following ICW surgery to assess for residual or recurrent disease and for ossicular chain reconstruction (OCR). The ICW procedure is distinguished from the CWD technique by the preservation of the posterior wall of the external auditory canal. Those who advocate this technique site the advantages of post-operative use of hearing aids, more rapid healing, allowance for water exposure (such as swimming), and decreased aural care compared with CWD. In addition, in some series, ICW has shown superior hearing results, although this may reflect the tendency to perform ICW for less severe disease [1]. The disadvantage of the ICW procedure is that exposure to the epitympanum and sinus tympani may be limited and the technique is technically more difficult. As a result, residual and recurrence rates have typically been higher with ICW compared to CWD [2,3]. The CWD procedure is characterized by removal of the posterior ear canal wall and the creation of a mastoid cavity. This technique allows improved exposure to the epitympanum and sinus tympani, areas difficult to visualize and prone to residual or recurrent disease. The mastoid cavity allows easier monitoring for recurrent disease. Indications for a CWD procedure include: disease in an only hearing ear, disease that cannot be safely removed (i.e. matrix covering a horizontal semicircular canal
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fistula) or cannot be visualized adequately with an ICW approach, recurrent disease secondary to a canal wall defect, a patient prone to poor followup or one that is an anesthetic risk. One stated disadvantage of the CWD technique is that the resultant mastoid cavity requires periodic cleaning and is more prone to otorrhea. The pediatric population poses a greater challenge than adults regarding cholesteatoma management. Children have higher rates of residual (disease intentionally or inadvertently left behind) and recurrent disease (due to a failed graft or new retraction pocket) compared with adults, possibly due to anatomic and physiologic differences [2,4— 7]. Eustachian tube anatomy and dysfunction predispose children to more frequent infections and retraction pockets, and well pneumatized mastoids in children allow for more extensive disease compared with more sclerotic mastoid bones in adults. The goals of cholesteatoma surgery are eradication of disease, preservation and/or improvement of hearing, and prevention of residual and/or recurrent disease. The management of pediatric cholesteatoma continues to be debated. In an attempt to help clarify the issue of the most appropriate management of pediatric cholesteatoma, we performed an 11-year retrospective review of our experience.
2. Materials and methods An 11-year retrospective review of children undergoing surgical intervention for cholesteatoma at our tertiary care pediatric hospital between 1 July 1992 and 1 July 2003, was performed. ICW and CWD procedures were compared regarding cholesteatoma recurrence and the need for revision surgery. We have defined recurrence as disease found at the time of second look which included disease purposely left at the time of the first operation (due to oval window involvement, dehiscent facial nerve involvement with extensive granulation tissue, etc.), as well as disease that was felt to have been fully excised but discovered at re-exploration. We
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did not include cases of recurrent cholesteatoma due to new retraction pockets or other causes. We only reported cases of disease purposefully or inadvertently left behind at the first stage. The outcomes of our second-look and OCR procedures were analyzed, as well as pre- and postoperative hearing results. The senior author performed all of the surgeries utilizing a facial recess approach for the ICW procedures. We did use otoendoscopy (1.7 mm endoscope with 30 or 708 view) when necessary to assess the sinus tympani or supratubal recess. When we encounter a narrow facial recess we choose to decompress or sacrifice the chorda tympani nerve rather than convert to a canal wall down procedure. All canal wall down cavities are partially obliterated with a large palva flap. No cases of CWD underwent canal wall reconstruction. A second-look procedure typically was performed at approximately 6—12 months with OCR at that time, if indicated. A CWD procedure was chosen in cases with large ear canal defects, semicircular canal fistula, and excellent pre-operative hearing in the involved ear or disease in an only hearing ear. Patients undergoing OCR had pre- and postoperative audiologic testing with average air and bone conduction, as well as pure tone averages, at 500, 1000, and 2000 dB. For ICW procedures, patients were seen every 3 months for the first post-operative year, every 6 months for years 2 through 4 and yearly thereafter. CWD patients were seen every 3—12 months, depending on mastoid cavity health.
3. Results There were 262 patients with 278 cases of cholesteatoma during the study period. Sixteen patients had bilateral disease. Primary acquired cholestea-
Chart 2
Chart 1 Location of initial cholesteatoma (n = 278 patients).
toma was found in 172 cases (61.9%), secondary acquired disease in 58 cases (20.9%), and disease of unknown etiology in 48 cases (17.2%). In those classified as unknown, disease was too extensive to determine its etiology as primary or secondary acquired. Congenital cholesteatoma cases were excluded from analysis. During initial surgery, the majority of disease was found in the attic region (122 cases), followed by the posterior/superior quadrant (96 cases) and the anterior epitympanum (8 cases). The entire middle ear space was noted to have cholesteatoma in 52 cases (Chart 1). The mean age at time of surgical intervention was 9.2 years (range 3—17). Sixty-five percent of the children were male. There was a slight predominance in right ear disease (52.5%) compared with the left ear. The average follow-up was 2.6 years with 87% having at least 5 years of follow-up (Chart 2). The overall recurrence rate for both ICW and CWD procedures was 16%, with a 17% recurrence rate for ICW and a 12% rate for CWD procedures (Table 1). Location of recurrent disease for both the
Follow-up (n = 278 cases of cholesteatoma).
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Table 1 Recurrencea results Procedure
Number of cases
Recurrence rate (%)
ICW CWD Overall
221 57 278
17 12 16
a
We have defined recurrence as disease found at the time of second look which included disease purposely left at the time of the first operation (due to oval window involvement, dehiscent facial nerve involvement with extensive granulation tissue, etc.), as well as disease that was felt to have been fully excised but discovered at re-exploration. We did not include cases of recurrent cholesteatoma due to new retraction pockets or other causes.
ICW and CWD groups was most commonly found in the posterior/superior quadrant, 69 and 86%, respectively (Chart 3). The majority (75.5%) of recurrences were noted within the first 3 post-
Chart 3
Chart 4
operative years and 88.8% occurred by post-operative year 5 (Chart 4). An ICW technique was used in 79% (221/278) of patients (Tree 1). Sixty-seven percent of these patients (148/221), underwent a planned secondlook procedure, while the remainder had single stage surgery. We used a single stage procedure in cases where disease did not involve the posterior superior quadrant, oval window or sinus tympani region and gross total excision was felt to have been achieved. Of those with a scheduled second-look surgery, all returned for their second procedure and 16% (24/148) demonstrated recurrent disease and 84% (124/148) of these patients underwent ICW revision surgery, with 17% (4/24) converted to a CWD procedure. Three patients who had no evidence of disease at time of second-look later developed recurrent cholesteatoma. Two of these patients had ICW revision procedures but were
Location of recurrent disease: ICW (n = 32) vs. CWD (n = 7).
Recurrence-time when disease noted on follow-up (n = 45 patients).
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Tree 1
ICW outcomes.
noted to have disease on follow-up and eventually underwent a CWD procedure. One patient who had a CWD revision as a result of their ICW second look procedure eventually developed disease and required a radical mastoidectomy. In the single-stage ICW group (n = 73), recurrent disease was noted in eight patients (11%). Five of
Tree 2
CWD outcomes.
these patients underwent an ICW revision and three had CWD procedures. One of the single-stage ICW revision patients later developed disease and underwent CWD surgery. CWD surgery was performed primarily in 57 patients (20.5%) (Tree 2). There were seven (12%) cases of recurrent cholesteatoma, for which six patients underwent revision CWD procedures, while one underwent a radical mastoidectomy for recurrent disease. Overall, 165 patients underwent attempted OCR, with 73% (n = 121) of these in the ICW group. Of the 121 patients, 97% underwent OCR at the time of second-look, with the remainder undergoing OCR at the primary procedure. At the second-look surgery, 75% (n = 88) underwent partial ossicular reconstruction (PORP), 22% (n = 26) had total ossicular reconstruction (TORP), and 3% (n = 3) had cartilage interposition grafting (Chart 5). The average pre-operative air-bone (A—B) gap in the ICW PORP group (n = 88) was 29.2 dB, with a post-operative A—B gap of 18.4 dB; representing a 10.8 dB improvement. The average pre-operative A—B gap in the TORP group was 32.2 dB, with a post
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4. Discussion
Chart 5 Types of ossicular chain reconstructions at time of ICW second-look procedure (n = 117).
operative A—B gap of 26.4 dB: representing a 5.8 dB improvement. In the CWD group, the average pre-operative A—B gap was 36.8 dB, with a post-operative gap of 33.1 dB: representing a 3.7 dB improvement (Chart 6). All patients with CWD procedures underwent cartilage graft interposition. Speech discrimination scores were not examined. There were no cases of sensorineural hearing loss or facial nerve injuries in our study. However, seven patients (4 ICW, 3 CWD) had post-operative otorrhea and two patients (both CWD) developed meatal stenosis. One patient had a post-operative hematoma that resolved without sequelae.
Chart 6
The primary goal of cholesteatoma surgery is complete eradication of disease with the secondary goal of hearing improvement post-operatively. Children with cholesteatoma have been shown to demonstrate more aggressive disease than adults with higher recurrence rates [2,4—9]. In this series, 79% of children with cholesteatoma were initially managed using an ICW approach, with only 4.5% (10/ 221) of these cases eventually requiring a CWD procedure. There was an overall recurrence rate of 16%, with an ICW rate of 17% and a CWD rate of 12%, which is consistent with the literature [2,9—14] (Table 2). Regardless of technique, recurrence rates for adults and children are between 7 and 57% [2,9— 14]. However, Tos et al. [15] reported results on 740 patients and found no differences in recurrence rates between the two approaches and fewer complications with ICW. They found recurrence to be more dependent on cholesteatoma location. Silvola and Palva [16] showed a correlation between postoperative retraction and recurrence and noted this to be especially problematic in the CWD group. In a follow-up study they found recurrent disease after revision surgery was most likely to be found in the attic or mesotympanum and usually developed from a retraction pocket [17]. Iino et al. [18] also found Eustachian tube dysfunction to be an important risk factor for recurrence. Other reports [9,10,19—22] indicate that operator experience, patient age, ossicular chain invol-
Hearing improvement after OCR.
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Table 2 Recurrence/recidivism rates in children Author
Patients (n) ICW/CWD
Glasscock et al. [4] Brown [10] Charachon and Gratacap [11] Sanna et al. [12] Parisier et al. [13] Dodson et al. [2] Darrouzet et al. [14] Ahn et al. [9]
142/2 62/36 99/37 114/4 62/103 41/17 189/21 19/102
vement, cholesteatoma size and location, and disease left behind at time of surgery correlate with recurrent disease. Most authors agree that recurrence is much more commonly seen when disease involves the round window, sinus tympani and ossicular chain in the posterior-superior quadrant. We agree with this conclusion and found the majority of our recurrences for both types of approaches were in the posterior/superior quadrant (Chart 3). Stern and Fazekas-May [21] demonstrated that the presence of disease in the sinus tympani necessitates a CWD procedure in 86—92% of patients. However, others argue that sinus tympani disease can still be explored with an ICW via a retrofacial approach with the aid of an endoscope for examination of the deep recess [2]. Those who favor the ICW procedure do so because it avoids water restrictions, periodic cleanings, and allows for more effective hearing aid use (if needed). However, a second look procedure is often recommended at 6—24 months post-operatively to assess for recurrent disease and to allow for OCR, if necessary. Interestingly, some authors have reported spontaneous resolution of residual cholesteatoma in 7—38% of cases [23,24]. Dodson’s [2] meta-analysis demonstrate a higher incidence of residual and recurrent disease (7—57%) with an ICW approach. These statistics, however, may be misleading as some consider the planned secondlook procedure to be an essential part of the ICW technique. Therefore, it has been argued that the residual cholesteatoma is not a complication or failure of the initial procedure [3]. Similar to other authors, we plan a second-look procedure between 6 and 12 months after the primary surgery to assess for recurrent cholesteatoma and for OCR, if needed. We found almost 90% of recurrent disease occurred within the first 5 years of follow-up, with 75% occurring within the first 3 years. This is similar to other reports [9,10] and emphasizes the importance of at least 5-year follow-up for these patients.
ICW (%)
CWD (%)
35 45
30 38
15 6 41 29 16
14 4 12 43 20
Overall (%) 46 34 42 40 10 36 31 19
We did not analyze recurrence rates based on patient age or ossicular chain involvement, although hearing results were clearly better with an intact stapes. We found our hearing results to be consistent with results shown by Murphy and Wallis [25], however, most authors [8,26—28] find no statistical difference in hearing results between the two techniques. Hearing results have been shown to be influenced by middle ear status, especially the integrity of the stapes suprastructure [3,29]. Mutlu [3] demonstrated a 25 dB hearing loss in 85% of those with an intact stapes supra structure, while only 53% of those without supra structure achieved this level. Our data is similar to Mutlu’s in that hearing improvement was greater for those undergoing PORP. Our average air-bone gap hearing improvement was 10.8 dB in the ICW PORP group. TORPs were performed in 22% of the ICW OCR group with an average hearing improvement of 5.8 dB. Many feel hearing results are more directly related to surgeon skill and ossiculoplasty success rather than type of tympanomastoidectomy. The senior author used the Strasnick PORP (GyrusTM) for the majority of the partial chain reconstructions. Theoretically, the 2.5 mm fully cannulated head improves visualization and allows more accurate prosthesis placement in the smaller pediatric ear. The head is also less top heavy, and therefore more evenly balanced, which possibly may improve ossiculoplasty success. Historically, worse hearing results have often been cited as a criticism of CWD but several studies dispute this notion [7,30—32]. Our results show that those undergoing CWD have worse hearing pre-operatively and less improvement post-operatively compared with children with the ICW approach. This may be a result of worse disease rather than failure in technique. Our CWD hearing improvement was less (3.7 dB improvement) compared with the ICW group (10.8 dB PORP/5.8 dB TORP improvements). It is difficult to compare the ICW and CWD groups in terms of OCR hearing
392 results because all patients in the CWD group received cartilage interposition grafts, and had more extensive disease. We believe the ICW with a facial recess approach offers comparable exposure and avoids the deleterious effects of a mastoid cavity, such as periodic debridement and water exposure restrictions. We have found the endoscope and mirrors to be especially helpful in examining poorly visualized areas. We feel the CWD should be reserved for large canal defects, semicircular canal erosion, an only hearing ear or a non-compliant patient. The reason for controversy may be partially due to surgeon training and preference, as well as patient selection bias. In addition, there have been few prospective studies examining the two techniques.
5. Conclusions ICW is a very successful technique in management of pediatric cholesteatoma. However, management requires a highly individualized approach that takes into account anatomic, clinical and social factors to determine the most successful surgical treatment paradigm. Patients who may be non-compliant with follow-up, have extensive disease with large canal wall defects and/or erosion of a semicircular canal, or have disease in their only hearing ear should undergo a CWD procedure.
References [1] J.A. Shohet, A.L. de Jong, The management of pediatric cholesteatoma, Otolaryngol. Clin. N. Am. 35 (2002) 841— 851. [2] E.E. Dodson, G.T. Hashisaki, T.C. Hobgood, et al., Intact canal wall mastoidectomy with tympanoplasty for cholesteatoma in children, Laryngoscope 108 (1998) 977—983. [3] C. Mutlu, A. Khashaba, E. Saleh, et al., Surgical treatment of cholesteatoma in children, Otolaryngol. Head Neck Surg. 113 (1995) 56—60. [4] M.E. Glasscock, Dickens JRE, R. Weit, Cholesteatoma in children, Laryngoscope 91 (1981) 1743—1753. [5] A.G. Shuring, W.H. Lippy, F.M. Rizer, et al., Staging for cholesteatoma in the child, adolescent and adult, Ann. Otol. Rhinol. Laryngol. 99 (1990) 256—260. [6] J. Bujia, A. Holly, F. Antoli-Candela, et al., Immunobiological peculiarities of cholesteatoma in children: quantification of epithelial proliferation by MIB 1, Laryngoscope 106 (1996) 865—868. [7] J.L. Sheehy, Cholesteatoma surgery in children, Am. J. Otol. 6 (1985) 170—172. [8] E. Vartiainen, J. Karja, S. Karjalainen, Surgery of chronic otitis media in young patients, J. Laryngol. Otol. 100 (1986) 515—519.
S.A. Schraff, B. Strasnick [9] S.H. Ahn, H.O. Seung, S.O. Chang, C.S. Kim, Prognostic factors of recidivism in pediatric cholesteatoma surgery, Int. J. Otorhinolaryngol. 67 (2003) 1325—1330. [10] J.S. Brown, A ten year statistical follow-up of 1142 consecutive cases of cholesteatoma; the closed versus open technique, Laryngoscope 92 (1982) 390—396. [11] R. Charachon, B. Gratacap, The surgical treatment of cholesteatoma in children, Clin. Otolaryngol. 10 (1985) 177— 184. [12] M. Sanna, C. Zini, R. Gamoletti, et al., The surgical management of childhood cholesteatoma, J. Laryngol. Otol. 101 (1987) 1221—1226. [13] S.C. Parisier, M.B. Hanson, J.C. Han, A.J. Cohen, B.A. Selkin, Pediatric cholesteatoma: an individualized, single-stage approach, Otolaryngol. Head Neck Surg. 115 (1996) 107— 114. [14] V. Darrouzet, J.Y. Duclos, D. Portmann, J.P. Bebear, Preference for the closed technique in the management of cholesteatoma of the middle ear in children: a retrospective study of 215 consecutive patients treated over 10 years, Am. J. Otol. 21 (2000) 474—478. [15] M. Tos, T. Lau, Late results of surgery in different cholesteatoma types, ORL J. Otorhinolaryngol. Relat. Spec. 51 (1989) 33—49. [16] J. Silvola, T. Palva, Long-term results of pediatric primary one-stage cholesteatoma surgery, Int. J. Pediatr. Otorhinolaryngol. 48 (1999) 101—107. [17] J. Silvola, T. Palva, One-stage revision surgery for pediatric cholesteatoma: long-term results and comparison with primary surgery, Int. J. Pediatr. Otorhinolaryngol. 56 (2000) 135—139. [18] Y. Iino, ImamuraY, C. Kojima, S. Takegoshi, J.I. Suzuki, Risk factors for recurrent and residual cholesteatoma in children determined by second stage, Int. J. Ped. Otorhinolaryngol. 46 (1998) 57—65. [19] G. Roger, F. Denoyelle, P. Chauvi, et al., Predictive risk factors of residual cholesteatoma in children: a study of 256 patients, Am. J. Otolaryngol. 18 (1997) 550— 558. [20] S. Strangerup, D. Drozdziewicz, M. Tos, Cholesteatoma in children, predictors and calculations of recurrence rates, Int. J. Otorhinolarnygol. 49 (1999) S69—S73. [21] S.J. Stern, M. Fazekas-May, Cholesteatoma in the pediatric population: prognostic indicators for surgical decision making, Laryngoscope 102 (1992) 1349—1352. [22] J. Sheehy, D.E. Brackman, M.D. Graham, Cholesteatoma surgery: residual and recurrent disease–—a review of 1024 cases, Ann. Otolaryngol. Rhinol. Laryngol. 86 (1977) 451— 462. [23] M. Glasscock, G. Miller, Intact canal wall tympanoplasty in management of cholesteatoma, Laryngoscope 86 (1976) 1639—1657. [24] J. Sheehy, J. Crabtree, Tympanoplasty: staging the operation, Laryngoscope 83 (1973) 1594—1621. [25] T.P. Murphy, D.L. Wallis, Hearing results in pediatric patients after canal-wall-up and canal-wall down mastoid surgery, Otolaryngol. Head Neck Surg. 119 (1998) 439—443. [26] D.R. Edelstein, S.C. Parisier, J.C. Han, Acquired cholesteatoma in the pediatric age group, Otolaryngol. Clin. North. Am. 22 (1989) 955—959. [27] A. Quaranta, P. Cassano, G. Carbonara, Cholesteatoma surgery: open versus closed tympanoplasty, Am. J. Otol. 9 (1988) 229—231. [28] S.E. Kinney, Five years experience using intact canal wall tympanoplasty with mastoidectomy for cholesteatoma: preliminary report, Laryngoscope 92 (1982) 1395— 1400.
Pediatric cholesteatoma [29] D.E. Brackman, Tympanoplasty with mastoidectomy: canal wall up procedures, Am. J. Otol. 14 (1993) 380— 382. [30] D. Roden, V.F. Honrubia, R. Weit, Outcome of residual cholesteatoma and hearing in mastoid surgery, J. Otolaryngol. 25 (1996) 178—181.
393 [31] B.E. Hirsch, D.B. Kamerer, S. Doshi, Single-stage management of cholesteatoma, Otolaryngol. Head Neck Surg. 106 (1992) 351—354. [32] J.G. Toner, G.D. Smyth, Surgical treatment of cholesteatoma: a comparison of three techniques, Am. J. Otol. 11 (1990) 247—249.
