Innovative computed tomography based mapping of the surgical posterior tympanotomy: An exploratory study

Area of Science:

• Otolaryngology
• Medical Robotics
• Surgical Navigation

Background:

• Robotic devices are enhancing cochlear implantation (CI) precision, reducing intracochlear damage.
• Understanding the surgical workspace is crucial for developing robotic insertion tools.

Purpose of the Study:

• To determine the dimensions of the cone-like surgical workspace from the posterior tympanotomy to the round window membrane.
• To provide initial data for planning robotically steered cochlear implantation.

Main Methods:

• Retrospective analysis of ten postoperative CT scans from adult CI patients.
• Measurement of workspace dimensions using four defined landmarks (P1-P4) and a standardized coordinate system.
• Calculation of maximal angles (α and β) and anteroposterior/inferosuperior ranges.

Main Results:

• The average angle α towards the round window membrane was 19.84° (±3.55°).
• The average angle β was 53.56° (±10.29°).
• Mean anteroposterior range: 2.25 mm (±0.42 mm); Mean inferosuperior range: 6.73 mm (±2.42 mm).
• Estimated distance from posterior tympanotomy to round window membrane: 6.05 mm (±0.71 mm).

Conclusions:

• The study provides initial data on the hypothetical maximum workspace for robotic cochlear implantation.
• These dimensions can inform the positioning of future robotic steering tools for automated electrode insertion.
• Larger sample sizes and preoperative scans are needed for population generalization and precise surgical planning.