Round and Oval Window Anatomic Variability: Its Implication for the Vibroplasty Technique.

Area of Science:

• Otolaryngology
• Biomedical Engineering
• Surgical Anatomy

Background:

• Middle ear implants like the Vibrant Soundbridge offer hearing restoration solutions.
• Understanding anatomical variability is crucial for successful implant integration.
• The round window (RW) and oval window (OW) are key implantation sites with distinct anatomical considerations.

Purpose of the Study:

• To assess anatomical variations in the round and oval window regions.
• To determine the relationship between these variations and implant stabilization.
• To evaluate the implications for Vibrant Soundbridge middle ear implant fitting.

Main Methods:

• Dissection of 85 human temporal bones to analyze round and oval window anatomy.
• Evaluation of Vibrant Soundbridge floating mass transducer (FMT) adaptation and stabilization in 67 RW and 22 OW cases.
• Assessment of surgical access and visualization of the RW niche via the facial recess approach.

Main Results:

• Successful FMT stabilization in the RW was achieved in 79% of cases.
• Factors hindering RW stabilization included small membranes (<1.5mm), high jugular bulb, and narrow niches.
• Oval window (OW) stabilization succeeded in 82% of cases; direct OW placement may offer easier access.
• Facial recess approach provided inadequate access for FMT placement in 22% of RW cases.

Conclusions:

• Vibroplasty at the round and oval windows presents surgical challenges.
• Anatomical conditions significantly influence FMT fitting and stabilization.
• Achieving stable FMT placement is the primary post-fitting challenge.