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Iatrogenic cholesteatoma in children with OME in a training program
International Journal of Pediatric Otorhinolaryngology (2006) 70, 1683—1686
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Iatrogenic cholesteatoma in children with OME in a training program Fatma Homood Al Anazy * King Abdulaziz University Hospital, P.O. Box 245, Riyadh 11411, Saudi Arabia Received 17 January 2005; received in revised form 15 October 2005; accepted 21 March 2006
KEYWORDS Iatrogenic; Cholesteatoma; Grommet tube; OME
Summary Purpose: To report the occurrence of cholesteatoma following myringotomy and insertion of ventilating tube (VT) in a residency training program. Materials and methods: Nine hundred and eighty-four children who were operated for grommet insertion with or without adenotonsillectomy during the year 1999—2003 were included in the study. Children were divided into two groups: group 1 (648 children) operated by residents and group 2 (305 children) operated by consultant. All procedures were carried out under general anesthesia using Ziess operating microscope. Shah ventilating tubes were used in most cases and Goody T tube in some others. Results: Nine ears developed cholesteatoma, six with perforation and three with pearl cholesteatoma cyst and intact tympanic membrane. The rate of iatrogenic cholesteatoma occurrence was 0.62% when done by residents (group 1) and 0.33% when operated by consultants (group 2). The overall prevalence was 0.48%. Conclusion: Iatrogenic cholesteatoma occuring as a complication following VT insertion is not uncommon. It occurs more often following surgery done by inexperienced surgeons. Excessive manipulation may cause meatal wall and drum surface epithelium injury. This epithelium might be pushed with the VT into the middle ear. # 2006 Published by Elsevier Ireland Ltd.
1. Introduction Grommet tube insertion with or without adenotonsillectomy is very common operation in our institution. Teaching program for oto-rhino-laryngology (ORL) is a recent one at King Abdulaziz University Hospital * Tel.: +966 1 4775735; fax: +966 1 4775748. E-mail address: [email protected].
Riyad, with 50 ENT beds. Postgraduate students rotate among the ENT departments of several hospitals. During this period, the junior trainees perform minor surgery as adenotonsillectomy and myringotomy with insertion of ventilating tubes. This is usually done under supervision of senior residents, registrars or consultants. Otitis media with effusion is a common childhood disease and surgery (myringotomy with VTs insertion) is the common operation performed to alleviate the child’s symptoms. The
0165-5876/$ — see front matter # 2006 Published by Elsevier Ireland Ltd. doi:10.1016/j.ijporl.2006.03.008
1684
F.H. Al Anazy
prevalence of OME in Saudi Arabia is 10.4% [1] below the age of 12 years. The indications for surgery vary between different hospital and consultants. The indications for grommet tube insertion in children with OME include the association with speech and language development delay, educational problems at school or behavioral problems in addition to recurrent ear infection [2]. Golz et al. (1999) revealed that the incidence of cholesteatoma formation associated with VT placement is as high as 1.1%. We report nine ears with cholesteatoma following myringotomy and placement of VT in training program.
2. Materials and methods Nine hundred and fifty-three children (1906 ears) with persistent OME that did not respond to medical treatment were included in the study. They underwent myringotomy with VT insertion mostly with adenoidectomy or adenotonsillectomy during the period April 1999 to February 2003. Those with atelectasis or retraction of tympanic membrane or suspection of cholesteatoma were excluded. They were divided into two groups: group 1 (648 cases) operated by trainees and group 2 (305 cases) were operated upon by consultants. Shah ventilating tubes were used in most cases. All the children had pre-operative tympanometry and the routine blood work up. Post-operative information on each child was recorded. Ziess operative
microscope was used to assess the tympanic membrane. Patients were followed up and assessed after 1, 3, 6, 12 months and then yearly up to 3 years.
3. Results This is a retrospective study where the medical files of 953 children aged 2—11 years were reviewed, they are divided into two groups –— group 1 comprised of 648 children (1296 ears) operated upon by residents, group 2 comprised of 305 children operated by consultants. The majority of the children attended almost regularly as their parents were informed of the tubes in the ear and advised of ear caring especially if their children demand of swimming. Follow-up was arranged to be after 1, 3, 6, 12, 24 and 36 months. Patients’ compliance was very good at the beginning as all of them came in the first month. The number of children in each group and the findings are presented in Table 1. Follow-up in 3 months was 92% in group 1 and 99% in group 2 while after 6 months it drops to 62 and 82%, respectively. The number of children attended in 1—2 years was 159 (32%) in group 1 and 152 (44.8%) in group 2. Those who did not show up after 6 months to 1 year was 159 (24.5%) in group 1 and 56 (18.4%) in group 2. The diagnosis of cholesteatoma was confirmed in nine cases. The rate of iatrogenic cholesteatoma in group 1 was 0.62% (eight ears); and in group 2 it was 0.33% (one case followed insertion of T-Goody tube).
Table 1 Characteristic of the two groups Group 1 operated by trainees; group 2 operated by consultant Follow-up –— 3 months Follow-up –— 6 months Follow-up –— 1—2 years Follow-up –— 3 years Did not attend after 6 months to 1 year Number of children developed suppurative otitis media Number of children developed recurrence (OME) and retubed VT removed from infected ears Cholesteatoma with perforation Pearl cholesteatoma (intact tympanic membrane) Prevalence of cholesteatoma Overall prevalence
Total 953
Group 1
Group 2
648 596 403 208 126 159
305 301 (99%) 209 (68.5%) 152 (44.8%) 73 (24%) 56 (18.4%)
(92%) (62%) (32%) (19.4%) (24.5%)
44 (6.8%)
11 (3.6%)
33 (5.1%)
10 (3.3%)
23 5 3
9 1
0.62% (0.48%)
0.33%
Iatrogenic cholesteatoma in children with OME in a training program
4. Discussion In a teaching hospital where trainees were rotating during their postgraduate program, they were the one who checked the patients and participated in surgery as part of their training. Senior residents or consultants sometimes supervise them. During performing VT insertion, excessive manipulation with meatal wall injury during the procedure resulted in bleeding with obscuring of vision and some epithelial tissue finding its way to the middle ear cavity. Sometimes the epithelial edge of the drum incision was pushed inward accidentally by the ventilating tube. Complications following the use of ventilating tubes are well documented and may be the result of either the operative procedures or due to anatomic and physiologic effect of the tube. The known complications include atrophy, atelec tasis, tympanosclerosis, persistent perforation and the development of cholesteatoma. These complications may be related to the type of tube used, the repeated incision and insertion, the occurrence of repeated infection and otorrhea or persistence of the tube for long period (over a year). Iatrogenic cholesteatoma following myringotomy and insertion of ventilating tube is rare. Herdman and Wright (1988) [4] reported an anterior tympanic cholesteatoma behind an intact drum at the site of previous VT placement in a child, which they called a ‘‘grommet cholesteatoma’’. The average incidence reported in a survey of 12 studies was 0.5% [5]. McLelland [6] reported one case of cholesteatoma that occurred secondary to the tube insertion process in a study of 697 ears. In a review of 2829 children following VT insertion during 20 years, Golz et al. [3] reported the incidence to be 1.1%. Other studies reported an incidence that ranged from 1.6 to 7% [7,8]. The development of cholesteatoma following intubation could be a direct complication of tubing as a result of shedding and implantation of epithelial cells into the middle ear or due to in growth of squamous epithelium from the perforation margin to the under surface of the drum, which is facilitated by the anges of the tube [3,9,10]. A complicated interaction of various processes may result in the development of cholesteatoma at the tube site and the presence of the tube may have a contributory effect [11]. On the other hand, some studies [12,13] concluded that using VT for treatment of OME might help to reduce the incidence of cholesteatoma in the long term. In our study, nine ears (0.62%) developed cholesteatoma as a result of insertion of tube; eight of
1685
them (1.34%) following surgeries performed by residents and one (0.33%) by a consultant. Follow-up in this study was limited to around 3 years, which probably is not long enough; but we had problems with patients’ compliance. More than 90% of the patients attended the clinic in the first 3 months post-operatively; then the rate declined with more than 20% of the patient did not attend after 6 months post tubing. About 5% of the children developed suppurative otitis media and 4% required retubing due to recurrence of the effusion (OME). Three of our cases of cholesteatoma had tube insertion twice. Long follow-up is advisable and it may reveal more cases. Cholesteatoma in children is said to be more extensive and aggressive than in adults [2]. This is due to many factors: faster the tissue growth, well pneumatized mastoid air system facilitating the spread of cholesteatoma [14,15]. The management of ears with pearl behind the drum is easier than that of the open extensive disease. Simple tympanotomy with removal of pearl and close follow-up is sufcient in most cases. The open cholesteatoma needs more extensive surgery; usually in the form of canal wall up or canal wall down mastoidectomy; depending on the extension and duration of the disease and the surgeon’s experience [16,17]. Long follow-up is always advisable. Success depends on early diagnosis and early surgical interference [18]. Golz et al. [3] concluded that periodic and long-term follow-up microscopic examinations of the eardrum should be performed in all patients following tube extrusion or removal, especially in those at high risk for developing a secondary choesteatoma in order to detect this complication as early as possible.
5. Conclusions Residents and ENT surgeons should be aware of this complication (development of cholesteatoma). Excess manipulation and meatal wall injury should be avoided. Careful follow-up is mandatory for all cases following tube removal or extrusion. Periodic microscopic visualization of tympanic membrane should be carried out.
References [1] S.M. Zakzouk, K.A. Al-Abdul Jawad, Point prevalence of type B tympanogram in children, Saudi Med. J. 23 (6) (2002) 708— 710. [2] K.A. Daly, L.L. Hunter, S.G. Giebink, Chronic otitis media with effusion, Pediatr. Rev. 20 (3) (1999) 85—93.
1686 [3] A. Golz, Goldenberg, D. Netzer, A.L.M. Westerman, S.T. Westerman, M. Fradis, et al., Cholesteatomas associated with ventilation tube insertion, Arch. Otolaryngol. Head Neck Surg. 125 (1999) 754—757. [4] Herdman, R.L.W. Wright, Grommets and cholesteatoma in children, J. Laryngol. Otol. 102 (1988) 1000—1002. [5] R.A. Buckingham, Cholesteatoma and chronic otitis media following middle ear intubation, Laryngoscope 91 (1981) 1450—1456. [6] C.A. McLelland, Incidence of complications from use of tympanostomy tubes, Arch. Otolaryngol. 106 (1980) 97—99. [7] W. Draf, P. Schulz, Insertion of ventilation tubes into the middle ear: results and complications, Ann. Otol. Rhinol. Laryngol. 89 (Suppl. 3) (1980) 303—307. [8] E. Vartiainen, J. Karfa, S. Kearjalainen, Surgery of chronic otitis media in young patients, J. Laryngol. Otol. 100 (1986) 515—519. [9] P.M. Jyoti, Mukherjee, Otitis media with effusion: an audit on the indications and outcome, Indian J. Otolaryngol. Head Neck Surg. 53 (4) (2001) 285—288. [10] A.F. Inglis, Typmanostomy tubes, in: C.W. Cummings, J.M. Fredirckson, L.A. Harder, C.J. Drause, M.A. Richardson, D.E. Schuller (Eds.),3rd ed., Otolaryngology Head and Neck Surgery, 5, Mosby-Year Book Inc., St. Louis, MO, 1998, pp. 478—487. [11] M. Mortensen, E.H.T. Lildholdt, Ventilation tubes and cholesteatoma in children, J. Laryngol. Otol. 89 (1984) 27—29.
F.H. Al Anazy [12] J.F. Sedrberg-Olsen, A.E. Sederberg-Olsen, A.M. Jensen, Late results of treatment with ventilation tubes for secretory otitis media in ENT practice, Acta Otolaryngol. 108 (1989) 448—455. [13] Y. Rakover, K. Keywan, G. Rosen, Comparison of the incidence of cholsteatoma before and after using ventilation tubes for secretary otitis media, Int. J. Pediatr. Otorhinolaryngol. 56 (2000) 41—44. [14] M. Arriaga, Cholesteatoma in children, Otolaryngol. Clin. N. Am. 27 (3) (1994) 573—591. [15] M. Bunne, M. Raivio, Pitfalls in diagnosis and treatment of cholesteatoma in children, in: M. Tos, J. Tomsen, E. Peitersen (Eds.), Cholesteatoma and Mastoid Surgery, Kugler & Ghedini Publ., Amsterdam, 1989, pp. 651—656. [16] J. Marco-Algarra, F. Gimenez, I. Mallea, M. Armengot, L. De la Fuente, Cholesteatoma in children: results in open vs. closed techniques, J. Laryngol. Otol. 105 (10) (1991) 820—824. [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] M. Bunne, M. Raivio, Long-term results after surgery for pediatric cholesteatoma. Otitis Media Today, in: M. Tos, J. Thomsen, V. Balle (Eds.), Proceedings of the Third Extraordinary Symposium on Recent Advances in Otitis Media, Copenhagen, 1—5 June, 1997, Dugler Publications, The Hague, The Netherlands, 1999, pp. 553—557.
www.elsevier.com/locate/ijporl
Iatrogenic cholesteatoma in children with OME in a training program Fatma Homood Al Anazy * King Abdulaziz University Hospital, P.O. Box 245, Riyadh 11411, Saudi Arabia Received 17 January 2005; received in revised form 15 October 2005; accepted 21 March 2006
KEYWORDS Iatrogenic; Cholesteatoma; Grommet tube; OME
Summary Purpose: To report the occurrence of cholesteatoma following myringotomy and insertion of ventilating tube (VT) in a residency training program. Materials and methods: Nine hundred and eighty-four children who were operated for grommet insertion with or without adenotonsillectomy during the year 1999—2003 were included in the study. Children were divided into two groups: group 1 (648 children) operated by residents and group 2 (305 children) operated by consultant. All procedures were carried out under general anesthesia using Ziess operating microscope. Shah ventilating tubes were used in most cases and Goody T tube in some others. Results: Nine ears developed cholesteatoma, six with perforation and three with pearl cholesteatoma cyst and intact tympanic membrane. The rate of iatrogenic cholesteatoma occurrence was 0.62% when done by residents (group 1) and 0.33% when operated by consultants (group 2). The overall prevalence was 0.48%. Conclusion: Iatrogenic cholesteatoma occuring as a complication following VT insertion is not uncommon. It occurs more often following surgery done by inexperienced surgeons. Excessive manipulation may cause meatal wall and drum surface epithelium injury. This epithelium might be pushed with the VT into the middle ear. # 2006 Published by Elsevier Ireland Ltd.
1. Introduction Grommet tube insertion with or without adenotonsillectomy is very common operation in our institution. Teaching program for oto-rhino-laryngology (ORL) is a recent one at King Abdulaziz University Hospital * Tel.: +966 1 4775735; fax: +966 1 4775748. E-mail address: [email protected].
Riyad, with 50 ENT beds. Postgraduate students rotate among the ENT departments of several hospitals. During this period, the junior trainees perform minor surgery as adenotonsillectomy and myringotomy with insertion of ventilating tubes. This is usually done under supervision of senior residents, registrars or consultants. Otitis media with effusion is a common childhood disease and surgery (myringotomy with VTs insertion) is the common operation performed to alleviate the child’s symptoms. The
0165-5876/$ — see front matter # 2006 Published by Elsevier Ireland Ltd. doi:10.1016/j.ijporl.2006.03.008
1684
F.H. Al Anazy
prevalence of OME in Saudi Arabia is 10.4% [1] below the age of 12 years. The indications for surgery vary between different hospital and consultants. The indications for grommet tube insertion in children with OME include the association with speech and language development delay, educational problems at school or behavioral problems in addition to recurrent ear infection [2]. Golz et al. (1999) revealed that the incidence of cholesteatoma formation associated with VT placement is as high as 1.1%. We report nine ears with cholesteatoma following myringotomy and placement of VT in training program.
2. Materials and methods Nine hundred and fifty-three children (1906 ears) with persistent OME that did not respond to medical treatment were included in the study. They underwent myringotomy with VT insertion mostly with adenoidectomy or adenotonsillectomy during the period April 1999 to February 2003. Those with atelectasis or retraction of tympanic membrane or suspection of cholesteatoma were excluded. They were divided into two groups: group 1 (648 cases) operated by trainees and group 2 (305 cases) were operated upon by consultants. Shah ventilating tubes were used in most cases. All the children had pre-operative tympanometry and the routine blood work up. Post-operative information on each child was recorded. Ziess operative
microscope was used to assess the tympanic membrane. Patients were followed up and assessed after 1, 3, 6, 12 months and then yearly up to 3 years.
3. Results This is a retrospective study where the medical files of 953 children aged 2—11 years were reviewed, they are divided into two groups –— group 1 comprised of 648 children (1296 ears) operated upon by residents, group 2 comprised of 305 children operated by consultants. The majority of the children attended almost regularly as their parents were informed of the tubes in the ear and advised of ear caring especially if their children demand of swimming. Follow-up was arranged to be after 1, 3, 6, 12, 24 and 36 months. Patients’ compliance was very good at the beginning as all of them came in the first month. The number of children in each group and the findings are presented in Table 1. Follow-up in 3 months was 92% in group 1 and 99% in group 2 while after 6 months it drops to 62 and 82%, respectively. The number of children attended in 1—2 years was 159 (32%) in group 1 and 152 (44.8%) in group 2. Those who did not show up after 6 months to 1 year was 159 (24.5%) in group 1 and 56 (18.4%) in group 2. The diagnosis of cholesteatoma was confirmed in nine cases. The rate of iatrogenic cholesteatoma in group 1 was 0.62% (eight ears); and in group 2 it was 0.33% (one case followed insertion of T-Goody tube).
Table 1 Characteristic of the two groups Group 1 operated by trainees; group 2 operated by consultant Follow-up –— 3 months Follow-up –— 6 months Follow-up –— 1—2 years Follow-up –— 3 years Did not attend after 6 months to 1 year Number of children developed suppurative otitis media Number of children developed recurrence (OME) and retubed VT removed from infected ears Cholesteatoma with perforation Pearl cholesteatoma (intact tympanic membrane) Prevalence of cholesteatoma Overall prevalence
Total 953
Group 1
Group 2
648 596 403 208 126 159
305 301 (99%) 209 (68.5%) 152 (44.8%) 73 (24%) 56 (18.4%)
(92%) (62%) (32%) (19.4%) (24.5%)
44 (6.8%)
11 (3.6%)
33 (5.1%)
10 (3.3%)
23 5 3
9 1
0.62% (0.48%)
0.33%
Iatrogenic cholesteatoma in children with OME in a training program
4. Discussion In a teaching hospital where trainees were rotating during their postgraduate program, they were the one who checked the patients and participated in surgery as part of their training. Senior residents or consultants sometimes supervise them. During performing VT insertion, excessive manipulation with meatal wall injury during the procedure resulted in bleeding with obscuring of vision and some epithelial tissue finding its way to the middle ear cavity. Sometimes the epithelial edge of the drum incision was pushed inward accidentally by the ventilating tube. Complications following the use of ventilating tubes are well documented and may be the result of either the operative procedures or due to anatomic and physiologic effect of the tube. The known complications include atrophy, atelec tasis, tympanosclerosis, persistent perforation and the development of cholesteatoma. These complications may be related to the type of tube used, the repeated incision and insertion, the occurrence of repeated infection and otorrhea or persistence of the tube for long period (over a year). Iatrogenic cholesteatoma following myringotomy and insertion of ventilating tube is rare. Herdman and Wright (1988) [4] reported an anterior tympanic cholesteatoma behind an intact drum at the site of previous VT placement in a child, which they called a ‘‘grommet cholesteatoma’’. The average incidence reported in a survey of 12 studies was 0.5% [5]. McLelland [6] reported one case of cholesteatoma that occurred secondary to the tube insertion process in a study of 697 ears. In a review of 2829 children following VT insertion during 20 years, Golz et al. [3] reported the incidence to be 1.1%. Other studies reported an incidence that ranged from 1.6 to 7% [7,8]. The development of cholesteatoma following intubation could be a direct complication of tubing as a result of shedding and implantation of epithelial cells into the middle ear or due to in growth of squamous epithelium from the perforation margin to the under surface of the drum, which is facilitated by the anges of the tube [3,9,10]. A complicated interaction of various processes may result in the development of cholesteatoma at the tube site and the presence of the tube may have a contributory effect [11]. On the other hand, some studies [12,13] concluded that using VT for treatment of OME might help to reduce the incidence of cholesteatoma in the long term. In our study, nine ears (0.62%) developed cholesteatoma as a result of insertion of tube; eight of
1685
them (1.34%) following surgeries performed by residents and one (0.33%) by a consultant. Follow-up in this study was limited to around 3 years, which probably is not long enough; but we had problems with patients’ compliance. More than 90% of the patients attended the clinic in the first 3 months post-operatively; then the rate declined with more than 20% of the patient did not attend after 6 months post tubing. About 5% of the children developed suppurative otitis media and 4% required retubing due to recurrence of the effusion (OME). Three of our cases of cholesteatoma had tube insertion twice. Long follow-up is advisable and it may reveal more cases. Cholesteatoma in children is said to be more extensive and aggressive than in adults [2]. This is due to many factors: faster the tissue growth, well pneumatized mastoid air system facilitating the spread of cholesteatoma [14,15]. The management of ears with pearl behind the drum is easier than that of the open extensive disease. Simple tympanotomy with removal of pearl and close follow-up is sufcient in most cases. The open cholesteatoma needs more extensive surgery; usually in the form of canal wall up or canal wall down mastoidectomy; depending on the extension and duration of the disease and the surgeon’s experience [16,17]. Long follow-up is always advisable. Success depends on early diagnosis and early surgical interference [18]. Golz et al. [3] concluded that periodic and long-term follow-up microscopic examinations of the eardrum should be performed in all patients following tube extrusion or removal, especially in those at high risk for developing a secondary choesteatoma in order to detect this complication as early as possible.
5. Conclusions Residents and ENT surgeons should be aware of this complication (development of cholesteatoma). Excess manipulation and meatal wall injury should be avoided. Careful follow-up is mandatory for all cases following tube removal or extrusion. Periodic microscopic visualization of tympanic membrane should be carried out.
References [1] S.M. Zakzouk, K.A. Al-Abdul Jawad, Point prevalence of type B tympanogram in children, Saudi Med. J. 23 (6) (2002) 708— 710. [2] K.A. Daly, L.L. Hunter, S.G. Giebink, Chronic otitis media with effusion, Pediatr. Rev. 20 (3) (1999) 85—93.
1686 [3] A. Golz, Goldenberg, D. Netzer, A.L.M. Westerman, S.T. Westerman, M. Fradis, et al., Cholesteatomas associated with ventilation tube insertion, Arch. Otolaryngol. Head Neck Surg. 125 (1999) 754—757. [4] Herdman, R.L.W. Wright, Grommets and cholesteatoma in children, J. Laryngol. Otol. 102 (1988) 1000—1002. [5] R.A. Buckingham, Cholesteatoma and chronic otitis media following middle ear intubation, Laryngoscope 91 (1981) 1450—1456. [6] C.A. McLelland, Incidence of complications from use of tympanostomy tubes, Arch. Otolaryngol. 106 (1980) 97—99. [7] W. Draf, P. Schulz, Insertion of ventilation tubes into the middle ear: results and complications, Ann. Otol. Rhinol. Laryngol. 89 (Suppl. 3) (1980) 303—307. [8] E. Vartiainen, J. Karfa, S. Kearjalainen, Surgery of chronic otitis media in young patients, J. Laryngol. Otol. 100 (1986) 515—519. [9] P.M. Jyoti, Mukherjee, Otitis media with effusion: an audit on the indications and outcome, Indian J. Otolaryngol. Head Neck Surg. 53 (4) (2001) 285—288. [10] A.F. Inglis, Typmanostomy tubes, in: C.W. Cummings, J.M. Fredirckson, L.A. Harder, C.J. Drause, M.A. Richardson, D.E. Schuller (Eds.),3rd ed., Otolaryngology Head and Neck Surgery, 5, Mosby-Year Book Inc., St. Louis, MO, 1998, pp. 478—487. [11] M. Mortensen, E.H.T. Lildholdt, Ventilation tubes and cholesteatoma in children, J. Laryngol. Otol. 89 (1984) 27—29.
F.H. Al Anazy [12] J.F. Sedrberg-Olsen, A.E. Sederberg-Olsen, A.M. Jensen, Late results of treatment with ventilation tubes for secretory otitis media in ENT practice, Acta Otolaryngol. 108 (1989) 448—455. [13] Y. Rakover, K. Keywan, G. Rosen, Comparison of the incidence of cholsteatoma before and after using ventilation tubes for secretary otitis media, Int. J. Pediatr. Otorhinolaryngol. 56 (2000) 41—44. [14] M. Arriaga, Cholesteatoma in children, Otolaryngol. Clin. N. Am. 27 (3) (1994) 573—591. [15] M. Bunne, M. Raivio, Pitfalls in diagnosis and treatment of cholesteatoma in children, in: M. Tos, J. Tomsen, E. Peitersen (Eds.), Cholesteatoma and Mastoid Surgery, Kugler & Ghedini Publ., Amsterdam, 1989, pp. 651—656. [16] J. Marco-Algarra, F. Gimenez, I. Mallea, M. Armengot, L. De la Fuente, Cholesteatoma in children: results in open vs. closed techniques, J. Laryngol. Otol. 105 (10) (1991) 820—824. [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] M. Bunne, M. Raivio, Long-term results after surgery for pediatric cholesteatoma. Otitis Media Today, in: M. Tos, J. Thomsen, V. Balle (Eds.), Proceedings of the Third Extraordinary Symposium on Recent Advances in Otitis Media, Copenhagen, 1—5 June, 1997, Dugler Publications, The Hague, The Netherlands, 1999, pp. 553—557.