Shape-memory stapes prosthesis for otosclerosis surgery

Area of Science:

• Biomaterials Engineering
• Otolaryngology
• Medical Device Development

Background:

• Stapes prostheses are crucial for hearing restoration in otosclerosis.
• Current prostheses may require complex surgical manipulation.
• A need exists for improved stapes prostheses offering enhanced ease of use and secure fit.

Purpose of the Study:

• To evaluate the efficacy of Nitinol (shape-memory alloy) as a component for an improved stapes prosthesis.
• To develop and test a novel Nitinol-based stapes prosthesis.

Main Methods:

• Prospective laboratory and clinical study involving Nitinol wire analysis (diameter, temperature variants).
• Measurement of 50 incus cadaver bones to determine prosthesis geometry.
• Evaluation of heat sources (electrocautery, lasers, warm water) for shape memory activation.
• Laboratory trials on human temporal bones and preliminary human subject trials.
• Magnetic resonance imaging (MRI) safety testing at 1.5 Tesla.

Main Results:

• Nitinol's shape-memory activated effectively with low heat, closing the prosthesis loop securely around the incus.
• Laser settings were well below bone-removal thresholds.
• MRI at 1.5 Tesla showed no prosthesis movement, indicating safety.
• Preliminary human trials demonstrated excellent air-bone closure and uniform incus contact.

Conclusions:

• The Nitinol piston prosthesis simplifies the stapedectomy procedure by reducing the need for manual surgical instruments.
• The inherent properties of Nitinol wire prevent over-crimping, ensuring a consistent fit.
• This Nitinol prosthesis presents significant advantages for otosclerosis surgery.