[Morphologic feature and cochlear implant surgical approach for cochlear modiolus deficiency]

Area of Science:

• Otolaryngology
• Neurosurgery
• Medical Imaging

Background:

• Cochlear modiolus deficiency presents a challenge for cochlear implant (CI) surgery.
• Accurate classification and tailored surgical approaches are crucial for optimizing CI outcomes in these cases.

Purpose of the Study:

• To review the classification of cochlear modiolus deficiency.
• To determine optimal surgical approaches for cochlear implant (CI) indications in patients with cochlear modiolus deficiency.

Main Methods:

• High-resolution computed tomography (HRCT) of the temporal bone was used for pre-operative classification.
• Patients were categorized into three groups based on the type of cochlear modiolus deficiency: Mondini malformation, Common cavity malformation, and IP-III malformation.
• Three surgical approaches (Type I, II, and III) were employed, differing in electrode array insertion and access points.

Main Results:

• 166 cases were classified: 135 Mondini, 18 Common cavity, and 13 IP-III malformations.
• Surgical approaches varied: Type I in 136 cases, Type II in 12, and Type III in 18.
• Post-operative speech recognition scores varied significantly: Mondini (moderate), Common cavity (poorest), and IP-III (best).

Conclusions:

• Cochlear modiolus deficiency impacts cochlear implant outcomes, with varying degrees of severity.
• Common cavity malformation demonstrates the poorest speech recognition outcomes.
• IP-III malformation shows the most favorable speech recognition outcomes following cochlear implantation.