Robotic Milling of Electrode Lead Channels During Cochlear Implantation in an ex-vivo Model.

Hermann, Jan; Mueller, Fabian; Schneider, Daniel; O'Toole Bom Braga, Gabriela; Weber, Stefan (2021). Robotic Milling of Electrode Lead Channels During Cochlear Implantation in an ex-vivo Model. Frontiers in Surgery, 8, p. 742147. Frontiers 10.3389/fsurg.2021.742147

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Objective: Robotic cochlear implantation is an emerging surgical technique for patients with sensorineural hearing loss. Access to the middle and inner ear is provided through a small-diameter hole created by a robotic drilling process without a mastoidectomy. Using the same image-guided robotic system, we propose an electrode lead management technique using robotic milling that replaces the standard process of stowing excess electrode lead in the mastoidectomy cavity. Before accessing the middle ear, an electrode channel is milled robotically based on intraoperative planning. The goal is to further standardize cochlear implantation, minimize the risk of iatrogenic intracochlear damage, and to create optimal conditions for a long implant life through protection from external trauma and immobilization in a slight press fit to prevent mechanical fatigue and electrode migrations. Methods: The proposed workflow was executed on 12 ex-vivo temporal bones and evaluated for safety and efficacy. For safety, the difference between planned and resulting channels were measured postoperatively in micro-computed tomography, and the length outside the planned safety margin of 1.0 mm was determined. For efficacy, the channel width and depth were measured to assess the press fit immobilization and the protection from external trauma, respectively. Results: All 12 cases were completed with successful electrode fixations after cochlear insertions. The milled channels stayed within the planned safety margins and the probability of their violation was lower than one in 10,000 patients. Maximal deviations in lateral and depth directions of 0.35 and 0.29 mm were measured, respectively. The channels could be milled with a width that immobilized the electrode leads. The average channel depth was 2.20 mm, while the planned channel depth was 2.30 mm. The shallowest channel depth was 1.82 mm, still deep enough to contain the full 1.30 mm diameter of the electrode used for the experiments. Conclusion: This study proposes a robotic electrode lead management and fixation technique and verified its safety and efficacy in an ex-vivo study. The method of image-guided robotic bone removal presented here with average errors of 0.2 mm and maximal errors below 0.5 mm could be used for a variety of other otologic surgical procedures.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Image Guided Therapy
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Hermann, Jan, Müller, Fabian Matthias, Schneider, Daniel, O'Toole Bom Braga, Gabriela, Weber, Stefan (B)


500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health
600 Technology > 620 Engineering






[42] Schweizerischer Nationalfonds




Jan Hermann

Date Deposited:

28 Dec 2021 11:39

Last Modified:

29 Mar 2023 23:38

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

electrode fixation electrode lead channel ex-vivo human cephalic study image-guidance patient-specific planning robotic cochlear implantation robotic milling robotic surgery




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