Author(s)
Iman Ghanad, BS
Elliott D. Kozin, MD
Danielle Trakimas, MSE
John Rosowski, PhD
Jeffrey Tao Cheng, PhD
Aaron K. Remenschneider, MD, MPH
Affiliation(s)
Abstract:
Hypothesis: Specific position of the stapes piston prosthesis along the incus long process influences sound-induced displacement magnitude.Background: During reconstruction following stapedotomy, a wire piston prosthesis placed over the incus and through the fenestrated footplate can reestablish sound transmission to the inner ear. Little is known, however, about how the discrete position of the wire along the length of the incus long process affects ossicular sound transmission.Methods: Cadaveric temporal bones without history of otologic disease underwent laser stapedotomy through a facial recess approach, maintaining an intact tympanic membrane. Stapes prosthesis was placed within the fenestrated footplate and crimped at three different locations (distal, middle and proximal), each 1 mm apart as measured from the end of the incus long process. Pure tone sound (200-10kHz) induced displacement measurements were obtained by laser Doppler vibrometry (LDV) at each incus long process position.Results: Prosthesis position influenced sound induced displacement in reproducible ways across the tested frequency range. The middle and distal positions demonstrated up to 4x greater displacement between 1k-4kHz compared to proximal position. Above 6 kHz, middle and distal positions delivered, on average 2x greater displacement than proximal positioning. Anatomic variability in incus long process position was observed between specimens.Conclusion: The position of stapes prostheses along the incus long process in stapedotomy affects sound induced motion. Middle and distal positioning tend to result in higher displacement magnitude than proximal positioning. These findings have implications for intraoperative positioning of stapes prostheses. Further studies are required to determine if position influences audiometric outcomes in humans.Define Professional Practice Gap & Educational Need: Little is known about how the incus position of a wire/piston stapes prosthesis affects sound induced motion after stapedectomy. To maximize sound conduction, especially at mid and high frequencies, optimal positioning of the prosthesis may afford improved audiometric results.Learning Objective: Understand how the relative position of the stapes piston along the incus long process affects sound induced motion of the prosthesis.Desired Result: Knowledge of the sound transmission effects of stapes prosthesis position will help guide surgical planning in stapedectomy.Level of Evidence: Does not apply, Basic science reportIRB: Exempt