Management of an Unusual Middle Ear Foreign Body

Presentation: A 42-year-old male was recently fitted for occupational ear molds to protect him from excessive noise exposure at work and further hearing loss. During the fitting, he experienced severe, sudden otalgia and vertigo and complained that hearing loss in the left ear, his better-hearing ear, had worsened. The dizziness resolved quickly, but the discomfort and hearing loss did not. He presented five days later with complaints of hearing loss and intermittent drainage but denied disequilibrium or vertigo.

The patient reported a history of multiple bilateral ventilation tubes as a child, a known right retracted tympanic membrane (TM) and bilateral hearing loss. An audiogram showed a right severe mixed hearing loss, with 74 percent word recognition, which was stable from prior testing. His left ear had new moderate-to-severe mixed hearing loss, with 84 percent word recognition. Tympanogram was type B bilaterally. Micro-otoscopy of the left ear revealed myringosclerosis, a healing traumatic TM perforation and a foreign body in the medial aspect of the ear canal extending through the anterosuperior tympanic membrane into the middle ear space.

—Submitted by by Joshua R. Mitchell, MD, Stanley Pelosi, MD, and Georges B. Wanna, MD, department of otolaryngology-head and neck surgery and The Otology Group of Vanderbilt, Vanderbilt University Medical Center, Nashville, Tenn.

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Figure 1: A) Left ear with blue foam foreign body (FB) visible through the native tympanic membrane (TM).

Figure 1: B) TM elevated, showing FB filling the middle ear and encasing the ossicles.

Figure 1: C) Status post FB removal, showing long arm of malleus and capitulum of stapes still in continuity.

Figure 1: D) Gross picture of FB fragments upon removal.

One important step to ear mold fitting is placement of a well-positioned and well-sealedprotective otoblock.

Figure 2: Acid-fast bacilli stain of laryngeal lesion, showing Mycobacterium tuberculosis (arrows).

Management:

The patient underwent a middle ear exploration. To maximize exposure, a post-auricular approach was utilized. The tympanic membrane perforation seen previously in the clinic was nearly healed, despite the presence of a middle ear foreign body. Blue foam material completely filled the middle ear, including hypotympanum, mesotympanum and epitympanum. The foreign body completely encased the ossicles (Figure 1). A decision was made to use a flexible CO₂ laser (Omniguide), along with a #1 knife, to break the amorphous material into manageable fragments that could be more easily dissected. Meticulous dissection was performed around the ossicles to preserve ossicular continuity. The foreign body was completely removed in a piecemeal fashion using cupped forceps. A tragal cartilage graft, together with a previously obtained temporoparietal fascial graft, was used for tympanic membrane reconstruction.

Discussion:

Certain foreign bodies in the ear can involve the middle ear, making removal difficult. A few sporadic reports describing middle ear foreign bodies as a complication of hearing aid ear mold fitting have been described.^1-4 Proper fitting of hearing aids follows established guidelines and rarely results in serious complications.1 One important step to ear mold fitting is placement of a well-positioned and well-sealed protective otoblock and atraumatic injection of properly prepared ear mold material.^5,6 Ear mold material escaping beyond the otoblock barrier can occur in cases of uncooperative patients, improper placement of the otoblock or overly aggressive injection of the ear mold material.

One author described molding material that entered a patient’s middle ear through pre-existing tympanic membrane perforations in both ears.⁷ Another report noted that all patients in their series with ear mold complications had pre-existing abnormalities in their aural anatomy, including tympanic membrane perforations, retraction pockets and mastoidectomy cavities, suggesting that patients with altered aural anatomy are at particular risk.⁸

Various techniques have been described for the removal of retained foreign body debris, including routine tympanomastoidectomy. In canal-wall-down patients with residual ear mold fragments after mold fitting, revision meatoplasty has been reported.¹

One author recommends that the stapes be directly visualized and the incudostapedial joint separated during removal of mold material that has encased the ossicles.⁸ We described a novel otologic method for removal not previously described in the literature using a combination of CO2 laser and cold knife dissection, while keeping the ossicles in continuity and preventing avulsion.

Mastoidectomy was not warranted in our particular case, because the entire mold could be removed piecemeal through the canal using the combination of the CO2 laser and cold knife dissection. In certain cases, however, a mastoidectomy may be beneficial to gain access to the epitympanum for retained FB fragments. The integrity of the ossicular chain was maintained in part due to the patient presenting to our clinic promptly after the incident, allowing a timely operative intervention. Reports demonstrate erosion of ossicles and ossicular discontinuity after delayed diagnosis.^1,8

Soon after his surgery, our patient was seen and reported hearing improvement and pain resolution. At four months post surgery, the patient was well healed, and his hearing had improved. His audiogram showed near complete closure of air bone gap and resolution of TM perforation.

References

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