Stapedectomy – Surgery for Otosclerosis

What is a Stapedectomy?

A stapedectomy is a microsurgical procedure performed on the middle ear in which the stapes – the smallest of the three tiny ossicles (hearing bones) in the middle ear – is completely or partially removed and replaced with a synthetic prosthesis. The procedure is primarily indicated for otosclerosis, a condition in which abnormal bone growth causes the stapes to become fixed in place, resulting in progressive conductive hearing loss.

The term derives from the Latin word stapes (stirrup) and the Greek ektomē (excision). A closely related and more commonly performed modern variant is the stapedotomy, in which a small hole is drilled into the stapes footplate rather than removing it entirely, and a piston prosthesis is inserted.

Causes and Indications

The most frequent reason for a stapedectomy is otosclerosis, a hereditary condition characterized by abnormal remodeling of the bony labyrinth of the inner ear. This leads to progressive fixation of the stapes footplate in the oval window, preventing the effective transmission of sound vibrations to the inner ear.

• Otosclerosis: primary indication; typically affects adults in middle age, more commonly women than men
• Congenital malformations: rare cases involving abnormal stapes development present from birth
• Tympanosclerosis: calcification of middle ear structures resulting from chronic middle ear infections

The decision to operate is made on an individual basis. A key prerequisite is adequate inner ear (cochlear) function, as the procedure improves sound conduction only and cannot reverse pre-existing sensorineural hearing loss.

Diagnosis

Prior to surgery, a comprehensive diagnostic evaluation is performed by an ENT specialist (otolaryngologist). Typical diagnostic measures include:

• Pure-tone audiometry: assessment of hearing thresholds across a range of frequencies and intensities
• Tympanometry: evaluation of eardrum mobility and the integrity of the ossicular chain
• Stapedial reflex testing: assessment of the acoustic reflex mediated by the stapedius muscle
• CT scan of the temporal bone: imaging of the bony structures of the middle and inner ear

The classic audiometric pattern in otosclerosis includes a conductive hearing loss with the so-called Carhart notch (a characteristic dip in the bone conduction audiogram at 2000 Hz) and an absent stapedial reflex.

Surgical Technique

Stapedectomy is typically performed under general anesthesia or local anesthesia with sedation and takes approximately 60 to 90 minutes. It is usually performed on an outpatient basis or with a brief hospital stay.

Steps of the Procedure

• Access to the middle ear is gained through the ear canal (transmeatal approach) under the operating microscope
• The eardrum (tympanic membrane) is carefully folded back to expose the middle ear cavity
• The stapes is detached from surrounding structures and removed (fully in stapedectomy, or with the footplate preserved in stapedotomy)
• A prosthesis (typically made of titanium or Teflon) is placed between the incus (anvil) and the oval window
• The eardrum is repositioned and secured

Stapedotomy as a Modern Variant

In the increasingly preferred technique of stapedotomy, a laser or fine drill is used to create a small opening (approximately 0.6–0.8 mm) in the stapes footplate. A piston prosthesis is then inserted into this opening and attached to the incus. This approach is considered less traumatic to inner ear structures and is associated with a lower risk of sensorineural hearing loss.

Outcomes and Success Rates

Stapedectomy is a well-established procedure with consistently high success rates. In carefully selected patients, a significant improvement in hearing is achieved in more than 90% of cases. Many patients attain near-normal hearing thresholds following surgery.

• Hearing improvement typically becomes apparent within weeks of the procedure
• Long-term hearing gain is maintained in the majority of cases
• Tinnitus (ringing in the ears) may also improve in some patients

Risks and Complications

As with any surgical procedure, stapedectomy carries potential risks that are thoroughly discussed with the patient prior to the operation:

• Sensorineural hearing loss or total deafness: rare but the most serious complication (approximately 1%)
• Vertigo and dizziness: usually temporary in the first days following surgery
• Taste disturbance: due to possible involvement of the chorda tympani nerve
• Tinnitus: new onset or worsening in rare cases
• Prosthesis displacement: may require revision surgery
• Infection or tympanic membrane perforation: very uncommon

Aftercare and Recovery

Following the procedure, patients are advised to observe the following precautions:

• Avoid blowing the nose for several weeks after surgery
• Refrain from air travel and diving for several weeks
• Protect the operated ear from water (no swimming or bathing without ear protection)
• Attend regular follow-up appointments with the ENT specialist to monitor hearing recovery
• Seek immediate medical attention in the event of sudden hearing deterioration or severe persistent dizziness

References

1. Strutz J., Mann W. (eds.): Praxis der HNO-Heilkunde, Kopf- und Halschirurgie. 3rd edition. Thieme Verlag, Stuttgart 2020.
2. Merchant S. N., Rosowski J. J.: Conductive hearing loss caused by third-window lesions of the inner ear. Otology & Neurotology, 2008; 29(3): 282–289. PubMed PMID: 18285782.
3. Chole R. A., McKenna M.: Pathophysiology of otosclerosis. Otology & Neurotology, 2001; 22(2): 249–257. PubMed PMID: 11300278.