Leaving a Lasting Impression: Ear Mold Impressions as Middle Ear Foreign Bodies

Download Leaving a Lasting Impression: Ear Mold Impressions as Middle Ear Foreign Bodies

Post on 05-Feb-2017




5 download


  • http://aor.sagepub.com/Annals of Otology, Rhinology & Laryngology

    http://aor.sagepub.com/content/115/12/912The online version of this article can be found at:

    DOI: 10.1177/000348940611501210

    2006 115: 912Ann Otol Rhinol LaryngolAbraham Jacob, Targhee J. Morris and D. Bradley Welling

    Leaving a Lasting Impression: Ear Mold Impressions as Middle Ear Foreign Bodies

    Published by:


    can be found at:Annals of Otology, Rhinology & LaryngologyAdditional services and information for

    http://aor.sagepub.com/cgi/alertsEmail Alerts:




    What is This?

    - Dec 1, 2006Version of Record >>

    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from


  • Annuls ofOtologv, Rhinology & Laryngology 115(12):912-916. 2006 Annals Publishing Company. All rights reserved.

    Leaving a Lasting Impression: Ear Mold Impressions as MiddleEar Foreign Bodies

    Abraham Jacob, MD; Targhee J. Morris; D. Bradley Welling, MD, PhD

    Objectives: We describe a series of otologic complications from impression material used to make hearing aid molds.

    Methods: We examined a retrospective case series of patients presenting to a tertiary care academic medical center.

    Results: The presentation, clinical course, and treatment outcomes of 6 patients with complications related to ear moldsare discussed. These patients had preexisting abnormalities in their aural anatomy, including tympanic membrane perfo-rations, retraction pockets, and mastoidectomy cavities.

    Conclusions: Although the majority of patients who have ear canal impressions taken experience no adverse outcomes,hearing aid dispensers should perform a thorough history-taking and physical examination to discern those with abnormalanatomy at risk for complications. These patients may benefit from evaluation in conjunction with an otolaryngologist.

    Key Words: ear mold, ear mold impression, hearing aid.


    Hearing loss affects nearly 30 million Americans,ie, I in 3 individuals over the age of 60 years, andnearly half of those over the age of 85 years. 1 As ourpopulation ages, the diagnosis and management ofhearing loss becomes an ever more pressing man-date for otolaryngologists and audiologists alike.Depending on the cause, a patient with hearing lossmay elect to have middle ear surgery, have an osseo-integrated auditory implant surgically placed, wearhearing aids, use assistive listening devices, or evenundergo cochlear implantation. With improvementsin hearing aid technology, amplification has becomean effective means of aural rehabilitation. Fitting ahearing aid usually requires the creation of an earmold. Audiologists typically take an impression ofthe patient's external auditory meatus and canal inorder to fashion a precise ear mold. Typically, dis-tal structures are protected with "otoblocks" or othersuch materials. This process is usually straightfor-ward but not completely devoid of risk. There area handful of reports in the scientific literature de-tailing middle ear and/or mastoid complications re-lated to ear mold impression material. We report theinadvertent extrusion of ear mold impression mate-rial into the middle ear or mastoid of 6 additionalpatients who then required otomicroscopic surgicalintervention for removal.


    The institutional review board at The Ohio State

    University Medical Center approved this humanstudies protocol. The senior author's (D.B.W.) sur-gical experience was reviewed to identify patientswith complications related to ear mold impressionmaterial. Their clinical presentations, imaging stud-ies, treatment plans, and clinical outcomes were re-corded and are presented here.


    Patient 1. A 75-year-old man with age-related,bilateral sensorineural hearing loss presented to alocal non-audiologist hearing aid dispenser for anaid. After bilateral ear mold impressions were tak-en, the material used could not be removed from thepatient's left ear, and an audiogram demonstrated anew, left-sided conductive hearing loss. The tym-panic membrane (TM) could no longer be visual-ized, because impression material filled the ear ca-nal. Attempts at removal in the office and under an-esthesia at a local facility near the patient's homewere unsuccessful. He was referred to our institutionfor further management. A high-resolution comput-ed tomography (CT) scan demonstrated that the for-eign body filled the ear canal and middle ear space.The patient was taken to the operating room, and aleft tympanoplasty, middle ear exploration, and in-tact-canal-wall mastoidectomy were performed. Theimpression material had passed through the TM per-foration, protruded into the middle ear, encased theossicular chain, extended inferiorly into the hypo-tympanum, and protruded anteriorly into the eusta-

    From the Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio.Correspondence: Abraham Jacob, MD, Dept of Otolaryngology-Head and Neck Surgery, The Ohio State University, 456 W 10th Ave,Suite 4A, Columbus, OH 43210.


    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from


  • Jacob et al, Ear Mold Impressions 913

    chian tube orifice. Most of the native TM, the incus,and the stapes superstructure were removed in orderto facilitate removal of the impression material in apiecemeal fashion. A tympanoplasty with ossicularreconstruction was performed. After operation, thispatient continued to have a mixed hearing loss forwhich he has since been fitted with a hearing aid.

    Patient 2. A 75-year-old man with a known TMperforation in his only hearing (right) ear presentedfor a hearing aid to the same local hearing aid dis-penser as in case 1. During the fitting, ear mold im-pression material was extruded into his middle earthrough the perforation. An immediate worseningof the patient's right-sided hearing loss was notedalong with new-onset pulsatile tinnitus. The physi-cal examination by a local otolaryngologist was sig-nificant for otorrhea, and he was sent to our insti-tution for further management. Our initial patientevaluation revealed extension of the impression ma-terial from the ear canal into the middle ear. A severemixed hearing loss was noted on his audiogram, anda high-resolution CT scan demonstrated soft tissuewithin the right ear canal and middle ear along withfluid within the mastoid cavity. The patient was tak-en to the operating room, and he underwent a righttranscanal tympanoplasty and middle ear explo-ration. Ear mold impression material encased theossicular chain and extended down the eustachiantube. Even with use of an argon laser, this materialcould not be removed safely, because it surroundedthe stapes superstructure in his only hearing ear. Thepatient was awakened, and after extensive discus-sion he underwent a second, more extensive proce-dure. A tympanomastoidectomy with facial recessapproach was performed to allow a better view ofthe stapes superstructure. The impression materialwas completely removed during this procedure, buthis postoperative audiogram showed a mixed hear-ing loss with a widened air-bone gap.

    Patient 3. An 80-year-old man with bilateral eu-stachian tube dysfunction, bilateral severe mixedhearing loss, and a known attic retraction pocket inthe left ear underwent hearing aid fitting at an out-side facility. After the impression was taken, moldmaterial became impacted within the patient's leftattic retraction pocket. A local otolaryngologist wasconsulted, but could not remove it in his office, andthe patient was referred on for further management.Our initial examination revealed impression mate-rial within the pars flaccida retraction pocket. Thehearing had subjectively decreased, and the audio-gram now demonstrated a worsened bilateral mixedloss. The patient underwent high-resolution CTscanning, which found an opacified middle ear and

    mastoid. After discussion, a tympanomastoidecto-my was recommended, but the patient refused. Hedid not return for subsequent scheduled visits andwas lost to follow-up.

    Patient 4. A 53-year-old man with a prior leftcanal-wall-down mastoidectomy was undergoinghearing aid fitting by our audiologist when the foamplug placed in his mastoid cavity was displaced me-dially and ear mold impression material extrudedinto his mastoid bowl. Our audiologist was unableto remove the material, and the patient was broughtto our clinic. After 90 minutes of piecemeal extrac-tion of impression material under the microscope,the foam plug was finally visualized. Once this plugwas removed, the rest of the mold material could beextracted. There were no further complications, andthe patient was refitted with a hearing aid.

    Patient 5. A 62-year-old man undergoing hearingaid fitting in his right ear reported acute pain andhearing loss upon removal of the ear mold impres-sion material. Evaluation by a local otolaryngologistat that time revealed that the impression material hadperforated the TM and was in contact with the ossi-cles. The patient refused surgical intervention at thattime. Over the subsequent year, a cholesteatoma de-veloped in this ear. He underwent surgery by a localotolaryngologist, who removed keratin matrix alongwith some impression material. After surgery, how-ever, the patient continued to suffer from persistentotalgia and otorrhea and was referred to our institu-tion for further management. Our evaluation foundan 80% TM perforation, residual middle ear chole-steatoma, audiological evidence of a mixed hearingloss, and opacification of the middle ear on CT. A re-vision right tympanomastoidectomy was performedwith removal of residual as opposed to recurrentcholesteatoma. A thorough inspection of the middleear revealed no persistent mold impression material,but the incudostapedial joint was separated and thelenticular process eroded. The incus was removedand reshaped as a bridge from the stapes to the mal-leus. It was unclear whether the erosion was relatedto removal of the ear mold material a year earlier orwhether the bone erosion had been caused by thecholesteatoma. A 4-month follow-up visit revealeda well-healed TM but a persistent air-bone gap. Ahearing aid was recommended.

    Patient 6. An 8-year-old boy presented to our of-fice with hearing loss and left-sided otorrhea. Hehad a history of recurrent otitis media and had hadpressure equalization tube placement bilaterally at1 year of age. During fitting for swim molds, theear mold impression material entered the middle earthrough his tympanostomy tubes. Evaluation by a

    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from


  • 914 Jacob et al, Ear Mold Impressions

    Fig 1. A) Normal anatomy of pinna, exter-nal auditory canal, tympanic membrane, andmiddle ear in coronal section. B) Ear moldimpression material (arrow) extends from ex-ternal auditory canal, through attic retractionpocket, into middle ear cleft. This materialsurrounds ossicular chain. C) Ear mold im-pression material (arrow) extends into middleear through tympanostomy tube. This is anal-ogous to such material entering middle earthrough tympanic membrane perforation.

    local otolaryngologist found that the material wasfirmly in position and could not be removed in theoffice. She attempted removal in the operating room,during which she found a small cholesteatoma. Atympanoplasty and removal of ear mold materialwas performed. Unfortunately, the tympanoplastywas unsuccessful and the perforation did not close.The patient was referred to our institution for revi-sion. He underwent a postauricular tympanoplasty,at which time the ossicular chain was noted to be in-tact. There was no evidence of recurrent cholestea-toma or persistent ear mold material, but the middleear mucosa was thickened and somewhat fibrotic.This time the perforation was closed.


    Hearing aid fittings are thought of as safe, con-servative options for aural rehabilitation in patientswith hearing loss. The majority of such patients un-

    dergo these fittings without complications. Althoughthe potential hazards are rare, otolaryngologists, au-diologists, and other hearing instrument dispensersmust be aware of them when taking ear mold im-pressions. As demonstrated by the above case se-ries, patients at particular risk are those with alteredaural anatomy. Those with perforations, retractionpockets (Fig IE), tympanostomy tubes (Fig Ie),and canal-wall-down mastoid cavities (Fig 2) areespecially vulnerable and should be informed of thisrisk. We recommend a careful otologic history-tak-ing and examination focused on prior ear surgery.If the entire TM cannot be completely visualized orthe anatomy appears unusual, the patient should bereferred to an otolaryngologist for further evalua-tion. For example, large, deep mastoid cavities mayneed to be packed with use of otologic instrumentsand a microscope before an impression is taken. Un-cooperative patients such as children or those withdevelopmental delay may require a trip to the oper-

    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from


  • Jacob et al, Ear Mold Impressions 915

    Fig 2. Diagrammatic representation of temporal bone incoronal section. Ear mold impression material is presentwithin canal-wall-down mastoidectomy cavity (arrow).

    ating room for making the impression under anes-thesia. For children, making impressions before eartube placement may also be worthwhile. Of course,taking ear mold impressions in patients with alteredear anatomy is not contraindicated. It necessitatestaking extra precautions.

    Choosing a more viscous mold material such assilicone might be more appropriate in patients withmastoid cavities or TM perforations. Powder andliquid preparations such as polyethylmethacrylate(powder) and methylmethacrylate monomer (liquid)are typically less viscous and can penetrate mastoidpacking or enter the middle ear through preexistingTM perforations. Care must also be taken while in-jecting the mold material, because excessive forcehas been reported to rupture an intact TM.1,2 Sili-cone slows down the speed at which impression ma-terial can be injected into the ear canal and lessensthis possibility. In patients with narrow ear canals,one must allow a space between the tip of the pistoland the introitus of the meatus so that excess moldmaterial can escape out of the ear rather than beforced medially.Z-' If the patient experiences signifi-cant pain or dizziness while the impression is beingtaken, the procedure should be stopped immediate-ly and the patient referred to an otolaryngologist. Ahigh-resolution CT scan of the temporal bone maybe required in order to adequately assess the extentof middle ear and/or mastoid penetration by the im-pression material! (Fig 3).

    Removing hardened ear mold impressions can

    Fig 3. High-resolution axial computed tomography scandemonstrates soft tissue (ear mold impression material)within right external auditory canal and middle ear space(arrow).

    generate significant negative pressure within the earcanal, resulting in pain, disruption of the TM, or os-sicular avulsion. New vented ear dams with hollowtubing do allow pressure equalization as the moldimpression material is removed. However, theirfoam consistency renders them more easily dis-placed by the impression material as it is injectedthan are cotton dams. Therefore, it is important tovisualize the entire TM after removing mold mate-rial in order to ensure that no injuries have occurred.If the impression does not separate easily, a CT scanof the temporal bones is necessary to visualize theossicles, eustachian tube, and mastoid. If mold ma-terial is found around the ossicular chain or withinthe mastoid, a mastoidectomy with a facial recessapproach may be necessary for removal (Fig 4). The

    Fig 4. Intraoperative photograph of ear mold impressionmaterial present within tympanomastoid cavity that re-quired postauricular approach for removal (arrow).

    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from


  • 916 Jacob et al, Ear Mold Impressions

    surgeon and patient should be prepared for this pos-sibility. We recommend that the stapes be directlyvisualized and the incudostapedial joint separatedduring removal of mold material that has encasedthe ossicles.

    With 6 patients, our report joins that of Kohanet all in forming the two largest case series to datedetailing complications related to ear mold impres-sions. Although it is not a common problem, physi-cians, audiologists, and technicians must be aware

    of this potential hazard.l> Many hearing instrumentdispensers work independently of physicians. Al-though this is reasonable in the majority of circum-stances, the dispenser must take an adequate history,perform a thorough examination, and realize his orher limitations when dealing with patients with al-tered aural anatomy. Training, experience, and ap-propriate clinical oversight may minimize compli-cations. This case series illustrates unfortunate pa-tient outcomes in what is considered by most to be aroutine procedure.

    Acknowledgments: The authors thank Jeffery Markley for the artwork. They also acknowledge input from lain L. Grant, MD, JasonT. Rich, MD, and BrianA. Neff, MD.


    I. Kohan D, Sorin A, Marra S, Gottlieb M, Hoffman R. Sur-gical management of complications after hearing aid fitting. La-ryngoscope 2004; 114:317-22.

    2. Kiskaddon RM, Sasaki CT. Middle ear foreign body. Ahearing aid complication. Arch Otolaryngol 1983;109:778-9.

    3. Hof JR, Kremer B, Manni JJ. Mould constituents in themiddle ear, a hearing-aid complication. J Laryngol Otol 2000;


    4. Syms CA III, Nelson RA. Impression-material foreignbodies of the middle ear and external auditory canal. Otolaryn-gol Head Neck Surg 1998;119:406-7.

    5. Mast WR, Judkins RF. Clandestine foreign body of themiddle ear: a warning to hearing aid dispensers. J Okla StateMed Assoc 1988;81:733-4.


    The Ninth International Symposi: .n on Recent Advances in Otitis Media will be held June 3-7, 2007, in St Pete Beach,Florida. For more information, contact the Otitis Media Symposium Office; telephone (213) 989-6741; fax (213) 483-5675; e-mailotitis2007@hei.org; or see the website http://www.hei.org/otitis2007.

    at NORTHERN ILLINOIS UNIV on September 6, 2014aor.sagepub.comDownloaded from