Quantitative Evaluation of the 3D Anatomy of the Human Osseous Spiral Lamina Using MicroCT.

PURPOSE: The osseous spiral lamina (OSL) is an inner cochlear bony structure that projects from the modiolus from base to apex, separating the cochlear canal into the scala vestibuli and scala tympani. The porosity of the OSL has recently attracted the attention of scientists due to its potential impact on the overall sound transduction. The bony pillars between the vestibular and tympanic plates of the OSL are not always visible in conventional histopathological studies, so imaging of such structures is usually lacking or incomplete. With this pilot study, we aimed, for the first time, to anatomically demonstrate the OSL in great detail and in 3D. METHODS: We measured width, thickness, and porosity of the human OSL by microCT using increasing nominal resolutions up to 2.5-µm voxel size. Additionally, 3D models of the individual plates at the basal and middle turns and the apex were created from the CT datasets. RESULTS: We found a constant presence of porosity in both tympanic plate and vestibular plate from basal turn to the apex. The tympanic plate appears to be more porous than vestibular plate in the basal and middle turns, while it is less porous in the apex. Furthermore, the 3D reconstruction allowed the bony pillars that lie between the OSL plates to be observed in great detail. CONCLUSION: By enhancing our comprehension of the OSL, we can advance our comprehension of hearing mechanisms and enhance the accuracy and effectiveness of cochlear models.

Feasibility of Pediatric Robotic Cochlear Implantation in Phantoms.

OBJECTIVE: To demonstrate the feasibility of robotic cochlear implant surgery in subject specific pediatric phantoms. STUDY DESIGN: Pilot study. MATERIALS AND METHODS: Computed tomographic preoperative encrypted data of 10 pediatric subjects (total of 20 sides) between 8 months and 48 months old, who underwent cochlear implant surgery were studied. Four datasets (n = 8 sides) were selected for investigation of the complete robotic procedure including middle and inner ear access and electrode insertion. RESULTS: The planning of the safe trajectory for the robotic approach was possible in 17 of the cases. In three sides, planning the trajectory was not possible due to the small size of the facial recess. Bone thickness study demonstrated average sufficient bone thickness at the site of screw implantation in general. The complete robotic procure including the drilling and insertion was successfully carried out on all the created phantoms. CONCLUSION: With this work we have demonstrated the feasibility of planning and performing a robotic middle and inner ear access and cochlear implantation (CI) in phantom models of pediatric subjects. To develop and validate the proposed procedure for use in children, next stage optimization of the current surgical workflow and adaptation of the surgical material to pediatric population is necessary.