Low-tone air-bone gaps after endolymphatic sac surgery.

Area of Science:

• Otolaryngology
• Neurosurgery
• Audiology

Background:

• Meniere's disease is a disorder of the inner ear.
• Endolymphatic sac surgery is a treatment for Meniere's disease.
• Chronic low-tone air-bone gaps (LTABGs) have been observed post-surgery.

Purpose of the Study:

• To investigate the mechanism behind LTABGs after endolymphatic sac surgery.
• To determine the relationship between intra-operative findings and post-operative LTABGs.

Main Methods:

• Study included 50 patients with Meniere's disease who underwent surgery over two years prior.
• LTABGs defined as a three-tone average of 20dB at 0.25, 0.5, and 1kHz.
• Intra-operative assessment focused on identifying the operculum (OPC).

Main Results:

• 50% of patients developed post-operative air-bone gaps (ABGs).
• Intra-operative OPC was present in 72% of patients and correlated with post-operative ABGs (p=0.013).
• Post-operative air-conduction hearing gain (aHG) and speech discrimination gain (SDG) were associated with ABGs (p=0.021 and p=0.0018, respectively).

Conclusions:

• Intra-operative OPC may cause post-operative ABGs, leading to improved hearing and speech discrimination.
• The findings suggest a mechanism similar to other conditions causing LTABGs via a third mobile inner ear window.
• Endolymphatic sac surgery, particularly with adequate decompression and steroid use, might induce LTABGs and contribute to beneficial surgical outcomes.