PREPRINT
jkl keys enabled
459 views

Laser Stapedotomy for Otosclerosis


Abstract

Otosclerosis can lead to progressive conductive hearing loss, significantly affecting the quality of life. For patients who choose surgery, the tympanic membrane is elevated and middle ear space is explored. If the surgeon confirms that the stapes is fixed in the oval window, either a stapedotomy or stapedectomy can be performed. In the stapedotomy, the surgeon removes the stapes superstructure, creates a fenestration in the footplate, and places a prosthesis from the incus through the fenestration into the vestibule. In this instance, the patient was able to regain nearly all of the hearing that had been lost as a result of stapes fixation.


Case Overview

Clinical Presentation

Typical for most patients with otosclerosis, our patient presented with gradually progressive hearing loss over many years. The patient denied any significant otologic history such as ear surgery, ear infections, trauma, noise exposure, or ototoxic medications. The patient’s mother had hearing loss in her late 40s and used a hearing aid.


Physical Exam

On physical exam, the patient’s external ears were normal in appearance. The external auditory canals were normal. The tympanic membranes were clear, without retraction or evidence of inflammation or middle ear effusion. There was no evidence of “Schwartze sign,” a pink coloration of the promontory suggestive of active otosclerosis. A tuning fork exam (512 Hz) was performed, demonstrating bone conduction greater than air conduction in the left ear (negative Rinne). A Weber test was performed, with lateralization to the left ear, confirming a conductive hearing loss. At 512 Hz, this is indicative of at least a 25-decibel air-bone-gap. Negative Rinne tests at 256 Hz and 1024 Hz imply air-bone-gap levels of 15 dB and 35 dB, respectively.


Adjunctive Studies

The patient’s audiogram demonstrated a conductive hearing loss across all frequencies. Hearing loss typically begins in the lower frequencies and advances to involve higher frequencies as the fixation becomes more widespread.

There was a “Carhart notch” at the 2000 Hz frequency (Figure 1). This is a mechanical artifact of testing, not a true sensorineural hearing loss. The normal ossicular resonance in humans is around 2000 Hz, which is impaired by stapes fixation.

Acoustic reflexes are also an important component of workup. If the stapes is affected by otosclerosis, corresponding reflexes will be decreased or absent in the affected ear. Tympanometry may also show a decreased (As) peak due to reduced compliance.


0189Fig1


Figure 1. Typical audiogram of a patient with otosclerosis. The Carhart effect is demonstrated at 2000 Hz.


Natural History

The majority of patients experience noticeable hearing loss in the 4th decade of life but may present with symptoms before or after this time. Given the heterogeneity of the disease process, predicting the progression and endpoint of the hearing loss remains difficult, particularly in instances of cochlear otosclerosis.

Options for Treatment

Patients can elect to observe their hearing loss, amplify environmental sounds with hearing aids, or undergo surgical intervention. Patients with poor speech discrimination scores preoperatively are likely to benefit less from surgery and should be counseled as such.

Rationale for Treatment

In this case, the patient’s hearing loss was significantly impacting her quality of life. She did not want to wear hearing aids and elected to undergo surgery.

Special Considerations

Patients with active middle ear infections or those with tympanic membrane perforations should not have a stapedotomy.

Equipment

  1. Standard microscopic ear tray instruments
  2. Laser: The selection of laser type is dependent on both surgeon and institutional preferences. The carbon dioxide or iridium laser are both effective.
  3. Drill: If the footplate or scutum requires drilling, this can be accomplished with small caliber drills (0.6 – 0.8 mm) set to lower RPM (8,000 – 10,000)
  4. Prosthesis: A wide variety of prostheses are available for use, typically dictated by surgeon preference.

Disclosure

Author C. Scott Brown also works as editor of the Otolaryngology section of the Journal of Medical Insight.


Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published on-line.


Citations

  1. De Souza, CE, Kirtane MV. Otosclerosis. Otorhinolaryngology – Head and Neck Surgery Series Otology and Neurotology. Noida, Uttar Pradesh, India: Thieme; 2013:204-226.
  2. Harrell RW. Pure tone evaluation. Handbook of Clinical Audiology. 5th ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2001:71-87