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Silicone impression material foreign body in the middle ear: Two case reports and literature review
Auris Nasus Larynx 42 (2015) 419–423
Contents lists available at ScienceDirect
Auris Nasus Larynx journal homepage: www.elsevier.com/locate/anl
Silicone impression material foreign body in the middle ear: Two case reports and literature review Nobuyoshi Suzuki, Koji Okamura, Takuya Yano, Hideaki Moteki, Ryosuke Kitoh, Yutaka Takumi, Shin-ichi Usami * Department of Otorhinolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto 390-8621, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 January 2014 Accepted 18 March 2015 Available online 5 May 2015
We report two cases of impression material foreign body in the middle ear. The first case had been affected with chronic otitis media. The silicone flowed into the middle ear through a tympanic membrane perforation during the process of making an ear mold. About 4 years and 8 months after, the patient had severe vertigo and deafness. We found bone erosion of the prominence of the lateral semicircular canal and diagnosed labyrinthitis caused by silicone impression material. In the second case silicone flowed into the canal wall down mastoid cavity. Both cases required surgery to remove the foreign body. The clinical courses in such cases are variable and timing of surgery is sometimes difficult. In addition to reporting these two cases, we present here a review of the literature regarding impression material foreign bodies. ß 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Silicone impression Foreign body Ear mold Hearing aid Middle ear Physical trauma
1. Introduction Hearing aids for severe to profound hearing loss require ear molds to be made and the provision of such molds has greatly increased. Making these ear molds is a rather simple and routinely performed procedure. However, it should be noted that there are certain high risk patients, such as those with perforations of the tympanic membrane, retraction pockets, tympanostomy tubes, and canal wall down mastoid cavities [1]. The silicone used to make ear molds is known to be a harmless material to the biological body, but if the middle ear is filled with silicone for a long period it will lead to severe middle and inner ear inflammation. We have experienced two cases of silicone impression material foreign bodies. Together with our case reports, we present here our review of the literature regarding such cases. 2. Case reports 2.1. Case 1 A 65-year-old man with chronic otitis media had experienced bilateral otorrhea for several years and become aware of hearing
* Corresponding author. Tel.: +81 263 37 2666; fax: +81 263 36 9164. E-mail address: [email protected] (S.-i. Usami). http://dx.doi.org/10.1016/j.anl.2015.03.010 0385-8146/ß 2015 Elsevier Ireland Ltd. All rights reserved.
loss. In August 2001, he visited a shop to purchase a hearing aid. Silicone impression material was introduced into his left ear canal with a manual impression gun and the patient immediately felt vertigo. Upon removal of the silicone, the apex of the impression broke off and remained in the external canal. The patient was referred to an ENT clinic where an otolaryngologist removed the silicone from the external canal but recognized that it had also flowed into the middle ear. Therefore, a high-resolution computed tomography (CT) scan was performed at a general hospital showing that the silicone impression material filled the middle ear space. The patient was then referred to our hospital. We found that the tympanic membrane was perforated and that the bluish silicone could be visualized through the perforation (Fig. 1A). The patient had left-pointing gaze nystagmus and it was assumed that a left side perilymph fistula occurred because of his vertigo. This was indeed confirmed by the CT findings, which showed the silicone protruded into the middle ear, encased the auditory ossicles and the stapes, extended into the hypotympanum, and even protruded into the Eustachian tube orifice (Fig. 1B). We explained the possible risk of severe hearing impairment caused by removal of the silicone and the patient denied surgery. According to his decision, together with the safety assurances provided by the silicone manufacturer, we performed only careful follow-up of his hearing. Intravenous steroid treatment resulted in an improvement in his vertigo and there was no noticeable progression of sensorineural hearing loss. He was discharged after 18 days of
420
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
Fig. 1. Case 1. (A) The external canal and tympanic membrane at the patient’s initial visit to our hospital. The external canal was inflammated. There was a small perforation in the tympanic membrane and the pale blue silicone can be seen through it (arrow) (August 2001). (B) CT scan taken at the referring hospital showing the impression material protruding into the middle ear, encasing the auditory ossicles, extending into the hypotympanum, and further protruding into the Eustachian tube orifice (August 2001). (C) Audiogram at the patient’s initial visit (August 2001). (D) Audiogram in June 2006. (E) CT scan taken immediately prior to surgical removal of the silicone had demonstrated that incus was destroyed and a part of the prominence of the lateral semicircular canal had a fistula (June 2006). (F) The largest portion of the silicone impression after we removed it (arrowhead, the part that had protruded into the Eustachian tube; arrow, the part that had filled the middle ear). We were unable to remove the silicone as one piece and had to cut and remove it in stages (June 2006).
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Fig. 2. Case 2. (A) Silicone impression material introduced into right ear canal. (B) CT scan indicating silicone impression material filled the open cavity. (C) Audiogram at the patient’s initial visit (April 2012). (D) Post-operative audiogram. Conductive hearing loss was improved after removal of the foreign body.
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
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treatment and continued to wear a hearing aid for his conductive hearing impairment (Fig. 1C). We monitored his condition through regular visits to our outpatient clinic but in April 2006, because of vertigo he went to an emergency hospital near his home where he obtained relief from intravenous drugs. In June 2006, we performed auditory testing and observed severe sensorineural hearing loss (Fig. 1D). A CT scan in January 2006 had demonstrated that incus was destroyed and a part of the prominence of the lateral semicircular canal had a fistula and it is likely that this fistula resulted in infection, causing the April episode of vertigo (Fig. 1E). The patient was thought to be at risk for bacterial labyrinthitis and associated CNS complications, therefore, in February 2007 we performed a mastoidectomy to remove the silicone foreign body. The silicone encased the ossicular chain and extended down the Eustachian tube and we removed it along with the malleus (Fig. 1F). We were not able to see the stapes, because of exuberant granulation and mucosal edema around the oval window. We were able to confirm the erosion and fistula of part of the prominence of the lateral
semicircular canal and repaired it with a bone chip and subdermal tissue. Based on the observation during surgery, there was no evidence of perilymphatic leakage from the round and oval windows. 2.2. Case 2 This case was a 70-year-old woman who had chronic otitis media from an early age, and in spite of receiving bilateral middle ear surgery in childhood, gradually became aware of hearing loss. In April 2012, she visited a shop to purchase hearing aids and silicone impression material was introduced into her right ear canal (Fig. 2A). However, due to a canal down mastoidectomy cavity, the silicone impression material could not be removed. She was then referred to our hospital. CT scan indicated that the silicone impression material filled the open cavity (Fig. 2B). Severe conductive hearing loss in her right ear was caused by the foreign body (Fig. 2C). We performed surgery to remove it by a post auricular approach 8 days later. Conductive hearing loss was improved after removal of the foreign body (Fig. 2D).
Table 1 Reported cases of impression material foreign bodies. Author
Age
Cause of hearing loss
Risk
Hearing loss due to foreign body/surgery
Vertigo due to foreign body
Period before surgery
Kiskaddon et al., 1983 [2] Mast et al., 1988 [3] Syms and Nelson, 1998 [4]
70
Chronic otitis media
Perforation
Sensorineural hearing loss
Severe
5 years
76
Perforation
Sensorineural hearing loss
Undescribed
1 month
72
Perforation of tympanic membrane Chronic otitis media
Perforation
Sensorineural hearing loss
Severe
1 day
61 58 63
Unspecified Chronic otitis media Age related hearing loss
Unspecified Perforation Unspecified
Sensorineural hearing loss Sensorineural hearing loss Sensorineural hearing loss
Severe Undescribed Severe
7
80
Age related hearing loss
None
Sensorineural hearing loss
Undescribed
8
34
Noise induced hearing loss
None
Severe
75 8
Unspecified Chronic otitis media
Unspecified Perforation
Perilymph fistula and sensorineural hearing loss Mixed hearing loss No hearing loss
1 week Undescribed Removed immediately by otologist Removed immediately by otologist 1 day
None None
1 year Undescribed
80
Age related hearing loss
Unspecified
Conductive hearing loss
Undescribed
6 months
12
60
Sensorineural hearing loss
Unspecified
Undescribed
2 weeks
13
60
4 years
9
No change (after surgery)
Undescribed
Undescribed
15 16
74 6
Age related hearing loss Cholesteatoma
Conductive hearing loss Mixed hearing loss
Undescribed Undescribed
Undescribed Undescribed
75
Sensorineural hearing loss
After operation (canal wall down) After operation (radical mastoidectomy) Narrow meatus After operation (canal wall down) None
Undescribed
14
Otosclerosis and sensorineural hearing loss Unspecified
No hearing loss (after surgery) No change
Mixed hearing loss
Undescribed
Undescribed
18 19
75 80
Undescribed Undescribed
Undescribed No removal
53
No change
Undescribed
Immediately
21 22 23
62 8 14
Unspecified Otitis media effusion Sensorineural hearing loss
Perforation Concave tympanic membrane After operation (canal wall down) Unspecified Ventilation tube None
Mixed hearing loss Mixed hearing loss
20
Chronic otitis media Eustachian tube dysfunction Cholesteatoma
Mixed hearing loss Unspecified Sensorineural hearing loss
Undescribed Undescribed Undescribed
1 year Undescribed 9 years
46
Chronic otitis media
Perforation
Unspecified
Undescribed
6 years
71 65
Chronic otitis media Chronic otitis media
Perforation Perforation
Unspecified Sensorineural hearing loss
Immediately 4 years
70
Conductive hearing loss
After operation (canal wall down)
No change
Severe Mild (severe 4 years later) None
Case 1 2 3 4 5 6
9 10 11
17
24 25 26 27
Wynne et al., 2000 [5]
Hof et al., 2000 [6] Kohan et al., 2004 [7]
Jacob et al., 2006 [1]
Awan et al., 2007 [8] Lee and Cho, 2012 [9] This study
8 days
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
3. Discussion Based on our literature review, there have been 25 reported cases of impression material foreign bodies (Table 1). The clinical courses and timing of surgery were varied. Fitting a hearing aid usually requires the making of an ear mold. This is not a difficult procedure but medical estimation is needed to evaluate lesions of the external canal and the tympanic membrane [5]. In addition, it should be noted that there are certain high risk patients, such as those having perforation of the tympanic membrane, retraction pocket, tympanostomy tubes, or canal wall down mastoid cavities [1]. In fact, our two cases both fell into these high risk categories. Based on the literature review, 15 out of 25 cases had high risk factors (perforation in 9, retraction of TM in 1, and operated ear in 4) (Table 1). Concerning symptoms, accelerated hearing loss and vertigo were frequently encountered. 18 of 25 patients had either conductive, mixed or sensorineural hearing loss, due to the foreign body and/or extraction surgery (Table 1). Six of the 25 patients experienced acute onset of vertigo, nausea and perilymph fistula when undergoing ear impression, while in others only conductive auditory impairment was seen [1–9] (Table 1). When residual silicone material is accompanied by vertigo and nausea, the patient likely has a perilymph fistula and the silicone may rupture the oval or round windows. If there is a fistula at the oval or round windows, perilymph leakage should be repaired. In all but 5 cases, hearing deterioration occurred due to the foreign bodies and/or surgery to remove them. Our Case 1 had mild vertigo at his first visit which then disappeared, but he then suffered severe vertigo 4 years later due to labyrinthitis. Sensorineural hearing loss was also associated with labyrinthitis. Our Case 2 had no vertigo but did have conductive hearing loss due to the foreign body. Surgery was required to remove the impression material from the middle or external ear in 24 out of the 25 cases (Table 1). The material has even been known to flow into the hypotympanum and Eustachian tube and to fill the mesotympanum [1,4,5,8,9]. The timing of surgery is sometimes difficult due to possible risks opposed to possible benefits and there are a variety of time courses. Based on the literature, the time period from the accident until surgery to remove the foreign body ranged in duration from immediately to 9 years after. From the material viewpoint, Ng described the long-term (1.2– 21.2 years) effects of a silicone sheet in the middle ear and reported it did not induce foreign body reaction, rejection or chronic inflammatory response [10]. Kiskaddon described a case study of a silicone impression remaining in the middle ear for more than five years in which the patient had vertigo and severe hearing impairment [2]. Awan reported the retrieval of an impression mold from the mastoid antrum after 9 years. In that case, the
423
silicone did not elicit any tissue reaction. Comparing that to our Case 1, it is likely that such a silent clinical course was due to the foreign body not filling all of the middle ear nor obstructing the Eustachian tube [8]. Lee recently reported two such cases; one of which suffered continuous infection for several years [9]. It should be noted that the silicone used as impression material is oily and therefore disturbs aeration through the Eustachian tube of the middle ear cavity, and the mucosa, inner ear and temporal bone will probably be adversely affected in 4 or 5 years. It may not be imperative to remove a foreign body of silicone impression material in the middle ear cavity immediately, but surgery should be scheduled at an early occasion. In Japan, revision to the pharmaceutical affairs law in April 2005 elevated hearing aids to the Class 2 category of medical devices so they are now subject to more control. A certification program for hearing aid technicians has also recently been developed, but it is unfortunate that the system is not mandatory and cases such as the current ones are not entirely avoidable. This situation should be improved as soon as possible by further revisions to the relevant laws and regulations in order to prevent cases such as the two presented above.
Conflict of interest This manuscript has not been published and has been submitted only to Auris Nasus Larynx. All the authors have read the manuscript and have approved this submission. This study received no support from any foundation. The authors report no conflicts of interest. References [1] Jacob A, Morris TJ, Welling DB. Leaving a lasting impression: ear mold impressions as middle ear foreign bodies. Ann Otol Rhinol Laryngol 2006;115:912–6. [2] Kiskaddon RM, Sasaki CT. Middle ear foreign body. A hearing aid complication. Arch Otolaryngol 1983;109:778–9. [3] Mast WR, Judkins RF. Clandestine foreign body of the middle ear: a warning to hearing aid dispensers. J Okla State Med Assoc 1988;81:733–4. [4] Syms 3rd CA, Nelson RA. Impression-material foreign bodies of the middle ear and external auditory canal. Otolaryngol Head Neck Surg 1998;119:406–7. [5] Wynne MK, Kahn JM, Abel DJ, Allen RL. External and middle ear trauma resulting from ear impressions. J Am Acad Audiol 2000;11:351–60. [6] Hof JR, Kremer B, Manni JJ. Mold constituents in the middle ear, a hearing-aid complication. J Laryngol Otol 2000;114:50–2. [7] Kohan D, Sorin A, Marra S, Gottlieb M, Hoffman R. Surgical management of complications after hearing aid fitting. Laryngoscope 2004;114:317–22. [8] Awan MS, Iqbal M, Sardar ZI. Iatrogenic insertion of impression mold into middle ear and mastoid and its retrieval after 9 years: a case report. J Med Case Reports 2007;2:3. [9] Lee DH, Cho HH. Otologic complications caused by hearing aid mold impression material. Auris Nasus Larynx 2012;39:411–4. [10] Ng M, Linthicum Jr FH. Long-term effects of Silastic sheeting in the middle ear. Laryngoscope 1992;102:1097–102.
Contents lists available at ScienceDirect
Auris Nasus Larynx journal homepage: www.elsevier.com/locate/anl
Silicone impression material foreign body in the middle ear: Two case reports and literature review Nobuyoshi Suzuki, Koji Okamura, Takuya Yano, Hideaki Moteki, Ryosuke Kitoh, Yutaka Takumi, Shin-ichi Usami * Department of Otorhinolaryngology, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto 390-8621, Japan
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 January 2014 Accepted 18 March 2015 Available online 5 May 2015
We report two cases of impression material foreign body in the middle ear. The first case had been affected with chronic otitis media. The silicone flowed into the middle ear through a tympanic membrane perforation during the process of making an ear mold. About 4 years and 8 months after, the patient had severe vertigo and deafness. We found bone erosion of the prominence of the lateral semicircular canal and diagnosed labyrinthitis caused by silicone impression material. In the second case silicone flowed into the canal wall down mastoid cavity. Both cases required surgery to remove the foreign body. The clinical courses in such cases are variable and timing of surgery is sometimes difficult. In addition to reporting these two cases, we present here a review of the literature regarding impression material foreign bodies. ß 2015 Elsevier Ireland Ltd. All rights reserved.
Keywords: Silicone impression Foreign body Ear mold Hearing aid Middle ear Physical trauma
1. Introduction Hearing aids for severe to profound hearing loss require ear molds to be made and the provision of such molds has greatly increased. Making these ear molds is a rather simple and routinely performed procedure. However, it should be noted that there are certain high risk patients, such as those with perforations of the tympanic membrane, retraction pockets, tympanostomy tubes, and canal wall down mastoid cavities [1]. The silicone used to make ear molds is known to be a harmless material to the biological body, but if the middle ear is filled with silicone for a long period it will lead to severe middle and inner ear inflammation. We have experienced two cases of silicone impression material foreign bodies. Together with our case reports, we present here our review of the literature regarding such cases. 2. Case reports 2.1. Case 1 A 65-year-old man with chronic otitis media had experienced bilateral otorrhea for several years and become aware of hearing
* Corresponding author. Tel.: +81 263 37 2666; fax: +81 263 36 9164. E-mail address: [email protected] (S.-i. Usami). http://dx.doi.org/10.1016/j.anl.2015.03.010 0385-8146/ß 2015 Elsevier Ireland Ltd. All rights reserved.
loss. In August 2001, he visited a shop to purchase a hearing aid. Silicone impression material was introduced into his left ear canal with a manual impression gun and the patient immediately felt vertigo. Upon removal of the silicone, the apex of the impression broke off and remained in the external canal. The patient was referred to an ENT clinic where an otolaryngologist removed the silicone from the external canal but recognized that it had also flowed into the middle ear. Therefore, a high-resolution computed tomography (CT) scan was performed at a general hospital showing that the silicone impression material filled the middle ear space. The patient was then referred to our hospital. We found that the tympanic membrane was perforated and that the bluish silicone could be visualized through the perforation (Fig. 1A). The patient had left-pointing gaze nystagmus and it was assumed that a left side perilymph fistula occurred because of his vertigo. This was indeed confirmed by the CT findings, which showed the silicone protruded into the middle ear, encased the auditory ossicles and the stapes, extended into the hypotympanum, and even protruded into the Eustachian tube orifice (Fig. 1B). We explained the possible risk of severe hearing impairment caused by removal of the silicone and the patient denied surgery. According to his decision, together with the safety assurances provided by the silicone manufacturer, we performed only careful follow-up of his hearing. Intravenous steroid treatment resulted in an improvement in his vertigo and there was no noticeable progression of sensorineural hearing loss. He was discharged after 18 days of
420
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
Fig. 1. Case 1. (A) The external canal and tympanic membrane at the patient’s initial visit to our hospital. The external canal was inflammated. There was a small perforation in the tympanic membrane and the pale blue silicone can be seen through it (arrow) (August 2001). (B) CT scan taken at the referring hospital showing the impression material protruding into the middle ear, encasing the auditory ossicles, extending into the hypotympanum, and further protruding into the Eustachian tube orifice (August 2001). (C) Audiogram at the patient’s initial visit (August 2001). (D) Audiogram in June 2006. (E) CT scan taken immediately prior to surgical removal of the silicone had demonstrated that incus was destroyed and a part of the prominence of the lateral semicircular canal had a fistula (June 2006). (F) The largest portion of the silicone impression after we removed it (arrowhead, the part that had protruded into the Eustachian tube; arrow, the part that had filled the middle ear). We were unable to remove the silicone as one piece and had to cut and remove it in stages (June 2006).
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
421
Fig. 2. Case 2. (A) Silicone impression material introduced into right ear canal. (B) CT scan indicating silicone impression material filled the open cavity. (C) Audiogram at the patient’s initial visit (April 2012). (D) Post-operative audiogram. Conductive hearing loss was improved after removal of the foreign body.
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
422
treatment and continued to wear a hearing aid for his conductive hearing impairment (Fig. 1C). We monitored his condition through regular visits to our outpatient clinic but in April 2006, because of vertigo he went to an emergency hospital near his home where he obtained relief from intravenous drugs. In June 2006, we performed auditory testing and observed severe sensorineural hearing loss (Fig. 1D). A CT scan in January 2006 had demonstrated that incus was destroyed and a part of the prominence of the lateral semicircular canal had a fistula and it is likely that this fistula resulted in infection, causing the April episode of vertigo (Fig. 1E). The patient was thought to be at risk for bacterial labyrinthitis and associated CNS complications, therefore, in February 2007 we performed a mastoidectomy to remove the silicone foreign body. The silicone encased the ossicular chain and extended down the Eustachian tube and we removed it along with the malleus (Fig. 1F). We were not able to see the stapes, because of exuberant granulation and mucosal edema around the oval window. We were able to confirm the erosion and fistula of part of the prominence of the lateral
semicircular canal and repaired it with a bone chip and subdermal tissue. Based on the observation during surgery, there was no evidence of perilymphatic leakage from the round and oval windows. 2.2. Case 2 This case was a 70-year-old woman who had chronic otitis media from an early age, and in spite of receiving bilateral middle ear surgery in childhood, gradually became aware of hearing loss. In April 2012, she visited a shop to purchase hearing aids and silicone impression material was introduced into her right ear canal (Fig. 2A). However, due to a canal down mastoidectomy cavity, the silicone impression material could not be removed. She was then referred to our hospital. CT scan indicated that the silicone impression material filled the open cavity (Fig. 2B). Severe conductive hearing loss in her right ear was caused by the foreign body (Fig. 2C). We performed surgery to remove it by a post auricular approach 8 days later. Conductive hearing loss was improved after removal of the foreign body (Fig. 2D).
Table 1 Reported cases of impression material foreign bodies. Author
Age
Cause of hearing loss
Risk
Hearing loss due to foreign body/surgery
Vertigo due to foreign body
Period before surgery
Kiskaddon et al., 1983 [2] Mast et al., 1988 [3] Syms and Nelson, 1998 [4]
70
Chronic otitis media
Perforation
Sensorineural hearing loss
Severe
5 years
76
Perforation
Sensorineural hearing loss
Undescribed
1 month
72
Perforation of tympanic membrane Chronic otitis media
Perforation
Sensorineural hearing loss
Severe
1 day
61 58 63
Unspecified Chronic otitis media Age related hearing loss
Unspecified Perforation Unspecified
Sensorineural hearing loss Sensorineural hearing loss Sensorineural hearing loss
Severe Undescribed Severe
7
80
Age related hearing loss
None
Sensorineural hearing loss
Undescribed
8
34
Noise induced hearing loss
None
Severe
75 8
Unspecified Chronic otitis media
Unspecified Perforation
Perilymph fistula and sensorineural hearing loss Mixed hearing loss No hearing loss
1 week Undescribed Removed immediately by otologist Removed immediately by otologist 1 day
None None
1 year Undescribed
80
Age related hearing loss
Unspecified
Conductive hearing loss
Undescribed
6 months
12
60
Sensorineural hearing loss
Unspecified
Undescribed
2 weeks
13
60
4 years
9
No change (after surgery)
Undescribed
Undescribed
15 16
74 6
Age related hearing loss Cholesteatoma
Conductive hearing loss Mixed hearing loss
Undescribed Undescribed
Undescribed Undescribed
75
Sensorineural hearing loss
After operation (canal wall down) After operation (radical mastoidectomy) Narrow meatus After operation (canal wall down) None
Undescribed
14
Otosclerosis and sensorineural hearing loss Unspecified
No hearing loss (after surgery) No change
Mixed hearing loss
Undescribed
Undescribed
18 19
75 80
Undescribed Undescribed
Undescribed No removal
53
No change
Undescribed
Immediately
21 22 23
62 8 14
Unspecified Otitis media effusion Sensorineural hearing loss
Perforation Concave tympanic membrane After operation (canal wall down) Unspecified Ventilation tube None
Mixed hearing loss Mixed hearing loss
20
Chronic otitis media Eustachian tube dysfunction Cholesteatoma
Mixed hearing loss Unspecified Sensorineural hearing loss
Undescribed Undescribed Undescribed
1 year Undescribed 9 years
46
Chronic otitis media
Perforation
Unspecified
Undescribed
6 years
71 65
Chronic otitis media Chronic otitis media
Perforation Perforation
Unspecified Sensorineural hearing loss
Immediately 4 years
70
Conductive hearing loss
After operation (canal wall down)
No change
Severe Mild (severe 4 years later) None
Case 1 2 3 4 5 6
9 10 11
17
24 25 26 27
Wynne et al., 2000 [5]
Hof et al., 2000 [6] Kohan et al., 2004 [7]
Jacob et al., 2006 [1]
Awan et al., 2007 [8] Lee and Cho, 2012 [9] This study
8 days
N. Suzuki et al. / Auris Nasus Larynx 42 (2015) 419–423
3. Discussion Based on our literature review, there have been 25 reported cases of impression material foreign bodies (Table 1). The clinical courses and timing of surgery were varied. Fitting a hearing aid usually requires the making of an ear mold. This is not a difficult procedure but medical estimation is needed to evaluate lesions of the external canal and the tympanic membrane [5]. In addition, it should be noted that there are certain high risk patients, such as those having perforation of the tympanic membrane, retraction pocket, tympanostomy tubes, or canal wall down mastoid cavities [1]. In fact, our two cases both fell into these high risk categories. Based on the literature review, 15 out of 25 cases had high risk factors (perforation in 9, retraction of TM in 1, and operated ear in 4) (Table 1). Concerning symptoms, accelerated hearing loss and vertigo were frequently encountered. 18 of 25 patients had either conductive, mixed or sensorineural hearing loss, due to the foreign body and/or extraction surgery (Table 1). Six of the 25 patients experienced acute onset of vertigo, nausea and perilymph fistula when undergoing ear impression, while in others only conductive auditory impairment was seen [1–9] (Table 1). When residual silicone material is accompanied by vertigo and nausea, the patient likely has a perilymph fistula and the silicone may rupture the oval or round windows. If there is a fistula at the oval or round windows, perilymph leakage should be repaired. In all but 5 cases, hearing deterioration occurred due to the foreign bodies and/or surgery to remove them. Our Case 1 had mild vertigo at his first visit which then disappeared, but he then suffered severe vertigo 4 years later due to labyrinthitis. Sensorineural hearing loss was also associated with labyrinthitis. Our Case 2 had no vertigo but did have conductive hearing loss due to the foreign body. Surgery was required to remove the impression material from the middle or external ear in 24 out of the 25 cases (Table 1). The material has even been known to flow into the hypotympanum and Eustachian tube and to fill the mesotympanum [1,4,5,8,9]. The timing of surgery is sometimes difficult due to possible risks opposed to possible benefits and there are a variety of time courses. Based on the literature, the time period from the accident until surgery to remove the foreign body ranged in duration from immediately to 9 years after. From the material viewpoint, Ng described the long-term (1.2– 21.2 years) effects of a silicone sheet in the middle ear and reported it did not induce foreign body reaction, rejection or chronic inflammatory response [10]. Kiskaddon described a case study of a silicone impression remaining in the middle ear for more than five years in which the patient had vertigo and severe hearing impairment [2]. Awan reported the retrieval of an impression mold from the mastoid antrum after 9 years. In that case, the
423
silicone did not elicit any tissue reaction. Comparing that to our Case 1, it is likely that such a silent clinical course was due to the foreign body not filling all of the middle ear nor obstructing the Eustachian tube [8]. Lee recently reported two such cases; one of which suffered continuous infection for several years [9]. It should be noted that the silicone used as impression material is oily and therefore disturbs aeration through the Eustachian tube of the middle ear cavity, and the mucosa, inner ear and temporal bone will probably be adversely affected in 4 or 5 years. It may not be imperative to remove a foreign body of silicone impression material in the middle ear cavity immediately, but surgery should be scheduled at an early occasion. In Japan, revision to the pharmaceutical affairs law in April 2005 elevated hearing aids to the Class 2 category of medical devices so they are now subject to more control. A certification program for hearing aid technicians has also recently been developed, but it is unfortunate that the system is not mandatory and cases such as the current ones are not entirely avoidable. This situation should be improved as soon as possible by further revisions to the relevant laws and regulations in order to prevent cases such as the two presented above.
Conflict of interest This manuscript has not been published and has been submitted only to Auris Nasus Larynx. All the authors have read the manuscript and have approved this submission. This study received no support from any foundation. The authors report no conflicts of interest. References [1] Jacob A, Morris TJ, Welling DB. Leaving a lasting impression: ear mold impressions as middle ear foreign bodies. Ann Otol Rhinol Laryngol 2006;115:912–6. [2] Kiskaddon RM, Sasaki CT. Middle ear foreign body. A hearing aid complication. Arch Otolaryngol 1983;109:778–9. [3] Mast WR, Judkins RF. Clandestine foreign body of the middle ear: a warning to hearing aid dispensers. J Okla State Med Assoc 1988;81:733–4. [4] Syms 3rd CA, Nelson RA. Impression-material foreign bodies of the middle ear and external auditory canal. Otolaryngol Head Neck Surg 1998;119:406–7. [5] Wynne MK, Kahn JM, Abel DJ, Allen RL. External and middle ear trauma resulting from ear impressions. J Am Acad Audiol 2000;11:351–60. [6] Hof JR, Kremer B, Manni JJ. Mold constituents in the middle ear, a hearing-aid complication. J Laryngol Otol 2000;114:50–2. [7] Kohan D, Sorin A, Marra S, Gottlieb M, Hoffman R. Surgical management of complications after hearing aid fitting. Laryngoscope 2004;114:317–22. [8] Awan MS, Iqbal M, Sardar ZI. Iatrogenic insertion of impression mold into middle ear and mastoid and its retrieval after 9 years: a case report. J Med Case Reports 2007;2:3. [9] Lee DH, Cho HH. Otologic complications caused by hearing aid mold impression material. Auris Nasus Larynx 2012;39:411–4. [10] Ng M, Linthicum Jr FH. Long-term effects of Silastic sheeting in the middle ear. Laryngoscope 1992;102:1097–102.