Cochlear implant electrode insertion: Jacobson's nerve, a useful anatomical landmark

Area of Science:

• Otolaryngology
• Neurosurgery
• Surgical Anatomy

Background:

• Traditional cochlear implant electrode insertion via the round window niche faces challenges like malpositioning into hypotympanic or infralabrynithine tracts.
• Round window niche location, bony overgrowth, or cochlear sclerosis can impede successful scala tympani intubation.
• Successful electrode placement is crucial for cochlear implant efficacy and depends on round window accessibility and cochlear basal turn patency.

Purpose of the Study:

• To identify factors influencing the ease of electrode array insertion during cochlear implantation.
• To develop a surgical technique that bypasses the cochlear hook area for improved electrode placement.
• To utilize the Jacobson's nerve (JN) as a reliable anatomical landmark for cochleostomy.

Main Methods:

• A novel surgical approach using the Jacobson's nerve (JN) as a landmark for cochleostomy was employed.
• Cochleostomy was performed by drilling anteriorly to or directly through the JN.
• Anatomical measurements were taken to correlate the inferior basal turn position relative to the JN with surgical outcomes.

Main Results:

• The Jacobson's nerve (JN) landmark facilitated cochleostomy and improved electrode array insertion into the scala tympani.
• Successful intubation of the scala tympani was achieved by targeting the inferior segment of the basal cochlear turn in relation to the JN.
• The study elucidated critical anatomical parameters for this refined surgical technique.

Conclusions:

• Utilizing the Jacobson's nerve (JN) as a landmark offers a reliable method for cochleostomy, enhancing scala tympani intubation.
• This technique effectively bypasses the challenging cochlear hook area, potentially reducing insertion complications.
• Precise anatomical understanding and landmark utilization are key to successful cochlear implant electrode placement.