Image-Based Planning of Minimally Traumatic Inner Ear Access for Robotic Cochlear Implantation

Abstract

Objective: During robotic cochlear implantation, an image-guided robotic system provides keyhole access to the scala tympani of the cochlea to allow insertion of the cochlear implant array. To standardize minimally traumatic robotic access to the cochlea, additional hard and soft constraints for inner ear access were proposed during trajectory planning. This extension of the planning strategy aims to provide a trajectory that preserves the anatomical and functional integrity of critical intra-cochlear structures during robotic execution and allows implantation with minimal insertion angles and risk of scala deviation.Methods: The OpenEar dataset consists of a library with eight three-dimensional models of the human temporal bone based on computed tomography and micro-slicing. Soft constraints for inner ear access planning were introduced that aim to minimize the angle of cochlear approach, minimize the risk of scala deviation and maximize the distance to critical intra-cochlear structures such as the osseous spiral lamina. For all cases, a solution space of Pareto-optimal trajectories to the round window was generated. The trajectories satisfy the hard constraints, specifically the anatomical safety margins, and optimize the aforementioned soft constraints. With user-defined priorities, a trajectory was parameterized and analyzed in a virtual surgical procedure.Results: In seven out of eight cases, a solution space was found with the trajectories safely passing through the facial recess. The solution space was Pareto-optimal with respect to the soft constraints of the inner ear access. In one case, the facial recess was too narrow to plan a trajectory that would pass the nerves at a sufficient distance with the intended drill diameter. With the soft constraints introduced, the optimal target region was determined to be in the antero-inferior region of the round window membrane.Conclusion: A trend could be identified that a position between the antero-inferior border and the center of the round window membrane appears to be a favorable target position for cochlear tunnel-based access through the facial recess. The planning concept presented and the results obtained therewith have implications for planning strategies for robotic surgical procedures to the inner ear that aim for minimally traumatic cochlear access and electrode array implantation.

A Self‐Configuring Deep Learning Network for Segmentation of Temporal Bone Anatomy in Cone‐Beam CT Imaging

“…These planning systems are also fundamental for minimally invasive procedures using multiport strategies 44 or keyhole approaches 45 to reach target anatomy without violating critical structures. Furthermore, image‐guided navigation 46 and robotic surgical systems 1,41,47‐52 have continued to shape the landscape of otology and neurotology by providing intraoperative methods for vital anatomy detection.…”

“…Due to the innately compact nature of the temporal bone, advances in pre-and intraoperative techniques have arisen to better visualize and avoid critical structures encased in bone. Preoperative planning pipelines using 3D model visualization software, 19,41 virtual reality, 42 and physically printed temporal bone models 43 for complex cases have shown improved visualization of patientspecific anatomy with a high degree of fidelity. These planning systems are also fundamental for minimally invasive procedures using multiport strategies 44 or keyhole approaches 45 to reach target anatomy without violating critical structures.…”

Suitable Electrode Choice for Robotic-Assisted Cochlear Implant Surgery: A Systematic Literature Review of Manual Electrode Insertion Adverse Events

“…A histopathological study by Ishiyama et al analyzed the temporal bones of CI patients who in life underwent CI surgery with either an RW or a Coch approach revealed that although insertion through a standard promontory Coch resulted in hydrops and fibrosis in both the ST and SV in the majority of subjects, RW insertions did not ( 100 ). Hence, RACIS aims for minimal traumatic inner ear access at the level of the RW in the case of normal anatomy ( 101 ).…”

Ex Vivo Evaluation of a Minimally Invasive Approach for Cochlear Implant Surgery

“…Additionally, the increasing demand for CIs secondary to the expansion of the indication criteria and the rapid increase of the aging population globally urges a significant simplification of CI surgery. Furthermore, simplifying CI surgery using a preplanned trajectory based on the individual anatomy could help improve structure preservation in patients with residual hearing [1]- [3].…”