Scala Tympani Versus Scala Vestibuli Cochlear Implantation in Incomplete Partition Type III Malformation

Area of Science:

• Otolaryngology
• Neuroscience
• Genetics

Background:

• Incomplete partition type III (IP-III) is a congenital inner ear malformation.
• IP-III is associated with severe-to-profound sensorineural hearing loss, making cochlear implantation (CI) the primary treatment.
• Surgical CI in IP-III is challenging due to potential electrode misplacement into the internal auditory canal (IAC) and risk of cerebrospinal fluid (CSF) gusher.

Purpose of the Study:

• To report a case of sequential cochlear implantation in a patient with bilateral IP-III malformation.
• To compare surgical and audiological outcomes of cochlear implantation via scala tympani versus scala vestibuli insertion.

Main Methods:

• Sequential cochlear implantation was performed in a patient with genetically confirmed bilateral IP-III malformation.
• The right cochlea underwent successful electrode insertion into the scala tympani.
• In the left cochlea, repeated attempts at scala tympani insertion led to electrode misplacement into the IAC; scala vestibuli insertion was then successful.

Main Results:

• Successful cochlear implantation in the scala tympani of the right ear.
• Electrode misplacement into the IAC occurred during attempted scala tympani insertion in the left ear.
• Successful electrode placement in the scala vestibuli of the left ear was achieved.

Conclusions:

• Cochlear implantation in IP-III malformations requires tailored surgical approaches.
• Scala vestibuli insertion may be a viable alternative when scala tympani access is compromised.
• This case highlights the importance of adapting surgical strategy for complex inner ear malformations.