|Year : 2009 | Volume
| Issue : 1 | Page : 43-45
Ear complications after hearing aids fitting
Fatma Hamoud AL-Anazy
Consultant and Associate Professor
|Date of Web Publication||7-Jan-2020|
MD KSUF Fatma Hamoud AL-Anazy
King Abdulaziz University Hospital, P.O. Box 245, Riyadh 11411
Source of Support: None, Conflict of Interest: None
We describe three cases with otological complications from impression material used to make hearing aids molds.
Keywords: foreign body, ear mold impression, hearing aids
|How to cite this article:|
AL-Anazy FH. Ear complications after hearing aids fitting. Saudi J Otorhinolaryngol Head Neck Surg 2009;11:43-5
| Introduction|| |
When medical or surgical intervention fails to correct hearing loss quality of live can be greatly improved with hearing aids. Recent advances in auditory technology, a progressively aging populations and change in the social attitude toward hearing aids usage have lead to a marked proliferation of hearing aids dispensation and use . Hearing aid moulds are used for several reasons. One of them is fitting of the hearing aid. Audiologists typically take an impression of the patient’s external auditory canal to fashion a precise ear mold and protects the middle ear with (otoblocks) or other such materials. This process is usually straightforward but not completely without risks. Proper fitting of the hearing aids following established guide line rarely results in serious complications. We report three cases as complications of hearing aids fittings.
| Case report 1|| |
A sixty year old lady with sensory-neural hearing loss and intact tympanic membrane was sent to the audiology department for right ear hearing aid fitting. The procedure was done by an intern. During the process of making the mold the patient suddenly experienced severe earache with dizziness and the procedure was abandoned. The patient was immediately referred to us .The patient was in pain, dizzy and complained of hearing loss more than before with nystagmus. Inspection of the right affected ear showed the ear mold material in the external canal, perforation of the tympanic membrane with the material in the middle ear cavity. Temporal bone CT scans [Figure 1] showed the material filling the right external auditory canal as well the right middle ear and engulfing the ossicles. Under general anesthesia the patient underwent a right tympanomastoidectomy with facial recess approach. The ear mold material was found filling the hypotympanum and the mesotympanum enclosing the ossicles, and the chorda tympani. The material was hard to remove and the chorda tympani was scarified during the process of freeing the ossicles. The material could not be removed completely from the stapes crurae and left in place. Post -operatively the patient developed vertigo which was treated conservatively . Her audiogram after three months showed mixed hearing loss in the right ear with no other complications.
|Figure 1: CT scans temporal bone axial view of soft tissue density in the middle ear cleft involving ossicles.|
Click here to view
|Figure 2: Temporal bone CT scan axial view of mold material in the Middle ear|
Click here to view
| Case report 2|| |
A forty five year lady, known case of bilateral chronic supportive otitis media with conductive hearing loss, refused surgery and opted for a hearing aid. She was advised to be fitted with a right sided hearing aid . During fitting she complained of some pain which faded with time . One month later the patient was seen in the clinic with the complaint of right sided ear discharge. After suction and cleaning a yellowish mass seen through the perforation which was hard and mainly in the mesotympanum. Temporal bone CT scan revealed heterogeneous opacification ff the right middle ear without ossicular erosion or dislocation. The audiogram showed bilateral hearing loss of 30-40 db . The patient was offered a right tympanoplasty with removal of the mould but she refused.
| Case report 3|| |
A 55- year old patient who with a past history of bilateral canal-wall down mastoidectomy due to cholesteatoma with hearing loss of 40 db bilaterally was seen in the clinic and advised a hearing aid. While she was undergoing the hearing aid fitting to the left ear ,the foam plug was displaced medially and the ear mold impression material extruded into the mastoid cavity. The patient was seen in the clinic and under the microscope the material was removed as piecemeal with out complica tions.
| Discussion:|| |
Over the past several decades, millions of patients with hearing loss have been successfully fitted with hearing aids with great improvement in quality of their lives. An essential prerequisite for hearing aids fitting use, is the ear mold fitting. Uncommon complications related to hearing aids fitting have been reported ,,. Improper placement of protective otoblocks or overly aggressive pressurized injection of the ear mold material during fitting may result in tympanic membrane perforations with the filling engulfing the middle ear. Fitting of hearing aids usually requires the creation of an ear mold. Audiologists typically take an impression of the patient’s external auditory meatus in order to fashion a precise ear mold . Typically the distal structures are protected with otoblocks or other such materials. This processes is usually straight forward but not completely without risk .There are a handful of reports in the literature reporting middle ear and mastoid complications  although the potential hazards are rare. Otolaryngologists and audiologist and other hearing instrument dispensers must be aware of them when taking ear mold impressions. Patients at particular risk are those with altered aural anatomy, tympanic membrane perforations, retractions pockets, tympanostomy tubes, and canal-wall-down mastoid cavities . A careful otological history and examination is mandatory to ovoid complications. If there is abnormality or the anatomy appears abnormal the patient should be referred to an otolaryngologest for farther evaluation. Choosing a more viscous mold material such silicon might be more appropriate in patients with mastoid cavities or tympanic membrane perforations. Powder and liquid preparations such as polyethylmethacrylate powder and methylmethacrylate monomer liquid are less viscous and can enter the middle ear through preexisting tympanic membrane perforation ,. Care must also be taken while injecting the mold material without excessive force which could cause tympanic membrane perforations ,.In patients with narrow external auditory canal one must allow a space between the tip of the pistol and the introitus of the meatus so that excess mold material can escape out of the ear rather than being forced medially ,. If the patient experiences pain, dizziness, or worsening of hearing, the procedure should be abandoned and the patient referred to an otolaryngologist. A high resolution CT of the temporal bone may be required to assess the extent of middle ear and mastoid involvement by the impression material. The hardened ear mold impression can result in pain, perforation of the tympanic membrane and injury to the ossicles. It is important to visualize the entire tympanic membrane after removing the mold material to insure that no injuries have occurred. If the impression dos not separate easily a CT scan of the temporal bone is needed to visualize the middle ear ossicles, mastoid, Eustachian tube More Details. Safe removal of ear mold material may require application of local anesthesia, to be performed in a properly equipped office sitting or the operating room .If the mold material is found in the middle ear cleft a mastoidectomy with a facial recess approach may be necessary for removal. Although it is not common problem, physicians, audiologist, and technicians must be aware of these potential hazards(10-11).
| Conclusion|| |
Proper fitting of hearing aids by a well trained professionals rarely results in complications. The hearing aids dispenser must take adequate history and perform through examination . Whenever complications are expected patient should be referred to an otolaryngolo gist.
Patient with impacted ear mold material in the middle ear or mastoid may need surgical intervention.
| References|| |
Kohan D.Levy L. Aural Rehabilitation Hearing Aid and Assistive Listening Devices. Alexandria ,VA: SIPAC American Academy of Otolaryngology -Head and Neck Surgery 1999. Pp.2.
Golenberg RL .Hearing Aids: A Manual For Clinicians .Philadelphia Lippincott – Raven. American Academy of Otolaryngology -Head and Neck Surgery 1996; 12-14.
Smriga DJ.Huber TP.Paparella MM. Developments in hearing aid fitting and delivery. Decade of revolution. Otol Clin North Am
Schimanaski G. Silicone foreign body in the middle ear caused by auditory canal impression in hearing aids fitting. HNO
Jacob A, Morris TJ, et al . Leaving a lasting impression as middle ear foreign bodies .Ann Otol Rhinol Laryngol
Kohan D, Sorin A, MarraS,. et al. Surgical management of complications after hearing aids fitting. Laryngoscope
Skaddon RM, Saski CT. Middle ear foreign body. A hearing aids complications. Arch Otolaryngol
Hof J R, Kremer B ,Manni JJ. Mould constituents in the middle ear, a hearing aid complication. J Laryngol Otol
Becker C,Fink U,Bujia J , et al. High resolution CT of the petrous bone for Locating a foreign body in the middle ear .Rontgenpraxis
Syms CA III,Nelson R A. Impression- material foreign bodies of the middle ear and external Auditory canal. Otolaryngol Head Neck Surg
Mast W R, Judkins R F,Clandestine . Foreign body of the middle ear a warning to hearing aids dispensers. J Okla State Med Assoc
[Figure 1], [Figure 2]