Management of Otosclerosis

Educational Objectives

The goal of this program is to improve improve the management of otosclerosis. After hearing and assimilating this program, the clinician will be better able to:

1. Select appropriate tests for the diagnosis of otosclerosis.
2. Counsel patients in the selection of a treatment strategy for osteosclerosis.

Summary

Otosclerosis: characteristic findings include conductive hearing loss, a Carhart notch on audiography, and normal otoscopic examination; on surgical examination, a red glow may be seen behind the tympanic membrane (Schwartze sign); fixation of the stapes at the anterior edge confirms the diagnosis; for most patients, hearing can be improved via surgery (sometimes, immediately following the procedure)

Epidemiology and etiology: the incidence of otosclerosis has decreased almost sixfold; the cause of this decrease is unknown; many theories have been proposed

Measles virus: involvement is suggested by the presence of viral particles and RNA fragments in footplate specimens or perilymph samples from patients with otosclerosis; the decline in incidence began 20 to 25 yr after the measles vaccine became widely available; however, the reduction in otosclerosis is far less than the reduction in measles infection; the time lag between the 2 events suggests involvement of other factors

Genetic predisposition: studies in monozygotic twins have shown concordance; literature includes reports of large families in which otosclerosis is transmitted in an autosomal dominant pattern, with 20% incomplete penetrance; in one of these families, a 15-base pair deletion that causes loss of function of the transcription factor FOXL1 was recently discovered; a zebrafish model was created for this gene

Manifestations of otosclerosis: among disorders of the bones, distinct in that it specifically affects the hearing bones; localization of disease in the anterior footplate classically produces conductive hearing loss, but otosclerosis may also present as sensorineural or mixed hearing loss; patients may present with chronic dizziness that is difficult to diagnosis and treat

Medical management: sodium fluoride — a systematic review by Hentschel et al (2014) found limited evidence of benefit and association with adverse effects; bisphosphonates — believed to inhibit osteoclastic activity, thereby reducing bone remodeling that cause formation of osteosclerotic foci; a systematic review by Patel et al (2022) demonstrated minimal evidence of benefit; the role of medical management is limited to patients with progressive sensorineural hearing loss not amenable to surgical treatment

Diagnostic assessments: tuning fork tests — Weber and Rinne tests are performed to confirm conductive hearing loss and estimate the degree of air-bone gap; may also prevent errors in judgment caused by inaccurate audiograms; acoustic reflex testing — simple to obtain; aids in distinguishing between hearing loss caused by fixation of the ossicular chain (which eliminates the reflex) and pseudo-conductive hearing loss (due to, eg, superior canal dehiscence)

Other tests: not routinely ordered for otosclerosis; temporal bone computed tomography (CT) — occasionally helpful; a normal scan does not rule out otosclerosis but can be useful if other lesions are suspected (eg, superior canal dehiscence when acoustic reflex is present, tympanosclerosis in cases of chronic infection); also useful for visualizing altered anatomy in patients with a history of prior ear surgery; a finding of bilateral osteosclerotic lesions at the oval window may indicate obliterative otosclerosis or a biscuit footplate (suggesting need to increase time for surgery); evidence of cochlear otosclerosis suggests the possibility of future sensorineural hearing loss; vestibular tests — may be ordered if patients present with dizziness, or if previous CT raises suspicion for dehiscence

Management options: aversion to wearing hearing aids significantly contributes to the preference for surgery; ≈66% of patients newly diagnosed with otosclerosis opt for surgery; a bone-anchored implant is an option but is not often chosen; cochlear implants are reserved for advanced disease; systematic reviews have compared stapedectomy vs cochlear implant in advanced otosclerosis and support stapedectomy as an option (closure of the air-bone gap may allow continued benefit from hearing aids); patient selection and discussion of risks is imperative; complications of surgery — excessively deep placement of implants in the vestibule may result in persistent dizziness; the apparent depth (on CT) may be affected by the composition of the prosthesis (ie, titanium vs fluoroplastic)

Co-occurring otosclerosis and superior canal dehiscence: may result in lower potential for improvement of hearing with surgery; patients should be informed of possible suboptimal outcomes

Readings

Abdelfatah N, Mostafa AA, French CR, et al. A pathogenic deletion in Forkhead Box L1 (FOXL1) identifies the first otosclerosis (OTSC) gene. Hum Genet. 2022;141(3-4):965-979. doi:10.1007/s00439-021-02381-1; Abdurehim Y, Lehmann A, Zeitouni AG. Stapedotomy vs cochlear implantation for advanced otosclerosis: Systematic review and meta-analysis. Otolaryngol Head Neck Surg. 2016;155(5):764-770. doi:10.1177/0194599816655310; Foster MF, Backous DD. Clinical evaluation of the patient with otosclerosis. Otolaryngol Clin North Am. 2018;51(2):319-326. doi:10.1016/j.otc.2017.11.004; Gillard DM, Harris JP. Cost-effectiveness of stapedectomy vs hearing aids in the treatment of otosclerosis. JAMA Otolaryngol Head Neck Surg. 2020;146(1):42-48. doi:10.1001/jamaoto.2019.3221; Hentschel MA, Huizinga P, van der Velden DL, et al. Limited evidence for the effect of sodium fluoride on deterioration of hearing loss in patients with otosclerosis: a systematic review of the literature. Otol Neurotol. 2014;35(6):1052-1057. doi:10.1097/MAO.0000000000000310; Patel S, Walters B, Eastwood M, et al. A systematic review of the effectiveness of bisphosphonates for otosclerosis. Otol Neurotol. 2022;43(5):530-537. doi:10.1097/MAO.0000000000003510; Sagar PR, Shah P, Bollampally VC, et al. Otosclerosis and measles: do measles have a role in otosclerosis? A review article. Cureus. 2020;12(8):e9908. Published 2020 Aug 21. doi:10.7759/cureus.9908.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose. Dr. Nguyen-Huynh's lecture includes information related to the off-label or investigational use of a therapy, product, or device.

Acknowledgements

Dr. Nguyen-Huynh was recorded at the Stanford Otology Update 2022, held in Palo Alto, CA, November 3-5, 2022, and presented by Stanford Medicine. For information about upcoming CME activities from this presenter, please visit https://med.stanford.edu/cme. Audio Digest thanks the speakers and Stanford Medicine for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.75 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.75 CE contact hours.

Lecture ID:

OT560403

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.