Predictive Value of 3D Radiological Segmentation and Anatomical Parameters for Cochlear Implantation Electrode Insertion Depth Based on a Large Sample of Patients with Inner Ear Malformations

The aims of this study were to investigate the clinical applicability of 3D segmentation in measuring cochlear anatomical parameters, explore factors that influence the insertion angle of cochlear implant electrodes in patients with inner ear malformations, and determine the value of 3D segmentation in predicting cochlear implant electrode insertion depth by simulating electrode implantation in a reconstructed 3D model.

Data from 208 temporal bone CT scans of patients with a variety of inner ear malformations (including the CH, IP-I, IP-II, and IP-III types) who underwent cochlear implantation at our center were retrospectively analyzed. Preoperative temporal bone CT data were subjected to three-dimensional (3D) segmentation of the cochlea with a 3D slicer.

Cochlear malformation types, including IP types I (42 ears), II (278 ears), III (20 ears), and CH (65 ears), were diagnosed and measured in 208 preoperative CT datasets. Cochlear anatomical parameters and electrode length were correlated, which partially explained the variations in electrode insertion angle. The mean angle of implantation among the enrolled patients was 564.33°, and the mean implantation angle prediction error in the 3D segmentation was |23.74|°.

Three-dimensional segmentation from temporal bone CT is valuable for surgeons, especially in treating patients with inner ear malformation. Such insights will help surgeons understand overall anatomical variations, predict electrode implantation depth, and complete preoperative imaging assessments for cochlear implant insertion depth in patients with inner ear malformations.