[Hearing ability after dissection of the vertebral nerve. A long-term study]

Area of Science:

• Neuroscience
• Otolaryngology
• Auditory and Vestibular Research

Background:

• The sympathetic innervation of the vertebral artery, known as the vertebral nerve (n. vertebralis Frank), is thought by some to influence auditory and vestibular functions.
• Previous research has not definitively established the role of this nerve in maintaining hearing and balance.

Purpose of the Study:

• To investigate the functional impact of the sympathetic vertebral nerve on auditory and vestibular systems in a rabbit model.
• To determine if disrupting the vertebral nerve leads to hearing loss or vestibular dysfunction.

Main Methods:

• Unilateral transection of the vertebral artery and its sympathetic plexus at the atlas level in rabbits.
• Auditory function assessed using Brainstem Evoked Response Audiometry (BERA).
• Vestibular function evaluated via electronystagmography (ENG) and clinical balance assessment.

Main Results:

• No significant changes in hearing thresholds were observed post-surgery, up to six months later.
• Brainstem Evoked Response Audiometry (BERA) showed no alterations in wave I-V latencies.
• Electronystagmography (ENG) and clinical examinations revealed no vestibular imbalance or differences between the two sides.

Conclusions:

• The experimental disruption of the sympathetic vertebral nerve did not result in measurable hearing loss or vestibular dysfunction in rabbits.
• Current findings suggest that the sympathetic innervation via the vertebral nerve may not play a critical role in maintaining auditory and vestibular function.