A 71-year-old man with a history of multiple ear surgeries presented for hearing rehabilitation. He denied having any pain or drainage. He had a canal wall down (CWD) mastoidectomy on the right side 60 years ago and a canal wall up (CWU) tympanomastoidectomy on his left side 20 years ago. Examination of both ear canals showed a 25 percent anterior tympanic membrane (TM) perforation on the right, a collapsed TM anteriorly, and a 50 percent inferior perforation on the left. The remainder of his head and neck examination showed normal results. His audiogram is below (Fig. 1).
Diagnosis: Bilateral Occult Cholesteatomas
It is common for patients to present for rehabilitation of conductive hearing loss years after an ear surgery. This usually occurs when age-related hearing loss starts to develop and worsens an existing baseline conductive hearing loss. Patients with a long-standing TM perforation also present a challenging case. These types of perforation don't usually cause drainage and only result in mild-to-moderate conductive hearing loss, which means patients may initially be able to tolerate or even not notice the loss of hearing. These perforations can be present for several decades without causing any issues as long as the patient is careful about water precautions. The problem arises when age-related, noise-induced, and/or genetic hearing loss starts to develop, worsening the patient's overall hearing, enough to impact quality of life and prompt him or her to seek hearing rehabilitation.
As the least invasive approach, hearing aids tend to be the first-line choice for these patients. However, hearing aids can pose a challenge to patients with a prior TM perforation. Hearing aids block the ear canal, promoting a humid environment ripe for bacterial and fungal growth. This can cause recurrent infection and otorrhea, preventing the patient from using hearing aids at all. Unfortunately, the advanced age at which these patients present usually means that any procedure requiring general anesthesia also carries a significant risk.
If the patient has no middle ear inflammatory disease or otorrhea, then the clinician can attempt to close the perforation. One in-office procedure is paper-patch myringoplasty, wherein a topical chemical peel agent (trichloroacetic acid 50%) is applied to the edges of the perforation and a paper patch is placed over it. This procedure works best in perforations that are less than 50 percent in size; the ideal size is less than 30 percent. With this procedure, the likelihood of closure drops significantly in perforations greater than 50 percent in size or those that involve the edge of the malleus.
Another method involves the porcine intestinal submucosal tissue, which comes as a packaged tissue. This method requires packing the middle ear with an absorbable gelatin and placing a tissue graft under the TM such that the graft strongly adheres to the edges of the perforation. We've received good results using this procedure in cases wherein a paper patch has failed.
Another in-office option is obtaining a subcutaneous fibro-fatty tissue from the postauricular area and using this as an underlay graft material. This procedure requires an incision behind the ear and more prepping and draping than the two methods previously described. Generally, perforations less than 50 percent in size can be closed in office. If all else fails, the patient can be offered a tympanoplasty with possible mastoidectomy. This procedure will require general anesthesia, but can rarely be done under local anesthesia if the patient is a poor candidate for general anesthesia.
Outpatient otology clinics typically get new patients with a history of ear surgery who don't provide any medical records from their previous physicians. To determine the possible reasons for new symptoms such as hearing loss, pain, or ear infections, the physician taking over the patient's care will need to identify the pathology of the patient's previous condition that required surgery. A CWD mastoidectomy, in which the posterior bony wall of the external auditory canal is removed, is generally done for a cholesteatoma. A CWU mastoidectomy, on the other hand, may be done for either a cholesteatoma or a TM perforation. CWU mastoidectomies allow for faster healing time and less long-term maintenance, but have a higher chance of recurrence of cholesteatomas. In some cases, a clinician can obtain a patient's previous operative report, which has the patient's primary pathology. However, operative reports are often unavailable, so one has to consider whether an occult cholesteatoma from a prior procedure could be responsible for the patient's symptoms.
For this patient, hearing aids may have been a good first step. However, the otoscopic exam should raise the level of suspicion that another process may be present behind the canal wall, particularly since the patient also had a CWD procedure on the other side, indicating a likely history of cholesteatoma. To evaluate for an occult cholesteatoma, we ordered an MRI, which showed a very large cholesteatoma in the patient's left mastoid. It was hidden from otoscopic view, and had eroded the bone overlaying the sigmoid and dura. Cholesteatoma is usually hyperintense (brighter than the brain) on T2, hypointense or isointense (darker or the same color as the brain) on T1 (Figs. 2A and 2B), and very bright on HASTE sequence (Figs. 3A and 2B). The lack of retraction pocket at the TM level indicated that the cholesteatoma was not new and most likely a residual that has been growing for over 20 years since the patient's last surgery.
Surprisingly, we also found a cholesteatoma on the right side where the patient had a CWD procedure (Figs. 3A and 4). This cholesteatoma was located at the geniculate ganglion, where newly grown bone seen on CT likely trapped some epithelial tissue, resulting in the cholesteatoma (Fig. 4). On the left side, the cholesteatoma had eroded the bone over the sigmoid sinus and posterior fossa dura. The patient elected to undergo surgery to remove the cholesteatomas and reconstruct the conductive hearing mechanism, with the goal to eventually use hearing aids.
BONUS ONLINE VIDEOS: VISUAL DIAGNOSIS
Read this month's Clinical Consultation case, then watch the accompanying videos from Hamid R. Djalilian, MD, to review the patient's imaging for yourself.
- Video 1. Axial (horizontal) CT showing the anatomy of the temporal bones.
- Video 2. Coronal (parallel to the face) CT of the right temporal bone showing the trapped epithelium medial to the bony growth in the geniculate ganglion area.
- Video 3. Sagittal (parallel to auricle) CT of the left temporal bone demonstrating destruction of the mastoid bone from the cholesteatoma.
- Video 4. Axial (horizontal) T2 MRI showing the hyperintense masses on both sides.
- Video 5. Axial (horizontal) T1 non-contrast MRI showing that the bright areas seen on the T2 MRI have the same or a darker color than the brain (hypointense).
- Video 6. Coronal (parallel to the face) HASTE sequence showing the areas of hyperintense (bright) signal on each side.
Watch the patient videos online at thehearingjournal.com.