Force measurement of insertion of cochlear implant electrode arrays in vitro: comparison of surgeon to automated insertion tool

Abstract Objectives (1) To evaluate the feasibility of a non-invasive, novel, simple insertion tool to perform automated, slow insertions of cochlear implant electrode arrays (EA) into a human cadaver cochlea; (2) to estimate the handling time required by our tool. Methods Basic science study conducted in an experimental OR. Two previously anonymized human cadaver heads, three commercially available EAs, and our novel insertion tool were used for the experiments. Our tool operates as a hydraulic actuator that delivers an EA at continuous velocities slower than manually feasible. Intervention(s): the human cadaver heads were prepared with a round-window approach for CI surgery in a standard fashion. Twelve EA insertion trials using our tool involved: non-invasive fixation of the tool to the head; directing the tool to the round window and EA mounting onto the tool; automated EA insertion at approximately 0.1 mm/s driven by hydraulic actuation. Outcome measurement(s): handling time of the tool; post-insertion cone-beam CT scans to provide intracochlear evaluation of the EA insertions. Results Our insertion tool successfully inserted an EA into the human cadaver cochlea (n = 12) while being attached to the human cadaver head in a non-invasive fashion. Median time to set up the tool was 8.8 (7.2–9.4) min. Conclusion The first insertions into the human cochlea using our novel, simple insertion tool were successful without the need for invasive fixation. The tool requires < 10 min to set up, which is clinically acceptable. Future assessment of intracochlear trauma is needed to support its safety profile for clinical translation.

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Magnetic Steering of Robotically Inserted Lateral-wall Cochlear-implant Electrode Arrays Reduces Forces on the Basilar Membrane In Vitro

Otology & Neurotology ◽

10.1097/mao.0000000000003129 ◽

2021 ◽

Vol Publish Ahead of Print ◽

Author(s):

Cameron M. Hendricks ◽

Matt S. Cavilla ◽

David E. Usevitch ◽

Trevor L. Bruns ◽

Katherine E. Riojas ◽

...

Keyword(s):

Cochlear Implant ◽

Basilar Membrane ◽

Lateral Wall ◽

Electrode Arrays ◽

Magnetic Steering

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Preliminary time estimations using a novel and simple insertion tool for cochlear implant electrode arrays: observations toward clinical application

10.1055/s-0041-1728434 ◽

2021 ◽

Author(s):

M. Geraldine Zuniga ◽

T Lenarz ◽

T Rau

Keyword(s):

Cochlear Implant ◽

Clinical Application ◽

Electrode Arrays ◽

Insertion Tool

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An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays

Otology & Neurotology ◽

10.1097/mao.0000000000001773 ◽

2019 ◽

Vol 40 (1) ◽

pp. 144

Keyword(s):

Cochlear Implant ◽

Lateral Wall ◽

Electrode Arrays ◽

Insertion Force

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An In-Vitro Insertion-Force Study of Magnetically Guided Lateral-Wall Cochlear-Implant Electrode Arrays

Otology & Neurotology ◽

10.1097/mao.0000000000001647 ◽

2018 ◽

Vol 39 (2) ◽

pp. e63-e73 ◽

Cited By ~ 5

Author(s):

Lisandro Leon ◽

Frank M. Warren ◽

Jake J. Abbott

Keyword(s):

Cochlear Implant ◽

Lateral Wall ◽

Electrode Arrays ◽

Insertion Force

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A simple tool to automate the insertion process in cochlear implant surgery

International Journal of Computer Assisted Radiology and Surgery ◽

10.1007/s11548-020-02243-7 ◽

2020 ◽

Vol 15 (11) ◽

pp. 1931-1939

Author(s):

Thomas S. Rau ◽

M. Geraldine Zuniga ◽

Rolf Salcher ◽

Thomas Lenarz

Keyword(s):

Cochlear Implant ◽

Infusion Pump ◽

Electrode Arrays ◽

Forward Motion ◽

Implant Surgery ◽

Simple Tool ◽

Cochlear Implant Surgery ◽

Slow Velocity ◽

Insertion Tool ◽

Insertion Process

Abstract Purpose Automated insertion of electrode arrays (EA) in cochlear implant surgery is presumed to be less traumatic than manual insertions, but no tool is widely available in the operating room. We sought (1) to design and create a simple tool able to automate the EA insertion process; and (2) to perform preliminary evaluations of the designed prototype. Methods A first prototype of a tool with maximum simplicity was designed and fabricated to take advantage of hydraulic actuation. The prototype facilitates automated forward motion using a syringe connected to an infusion pump. Initial prototype evaluation included: (1) testing of forward motion at different velocities (2) EA insertion trials into an artificial cochlear model with force recordings, and (3) evaluation of device handling, fixation and positioning using cadaver head specimens and a surgical retractor. Alignment of the tool was explored with CT imaging. Results In this initial phase, the prototype demonstrated easy assembly and ability to respond to hydraulic actuation driven by an infusion pump at different velocities. EA insertions at an ultra-slow velocity of 0.03 mm/s revealed smooth force profiles with mean maximum force of 0.060 N ± 0.007 N. Device positioning with an appropriate insertion axis into the cochlea was deemed feasible and easy to achieve. Conclusions Initial testing of our hydraulic insertion tool did not reveal any serious complications that contradict the initially defined design specifications. Further meticulous testing is needed to determine the safety of the device, its reliability and clinical applicability.

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Optimizing the Magnetic Dipole-Field Source for Magnetically Guided Cochlear-Implant Electrode-Array Insertions

Journal of Medical Robotics Research ◽

10.1142/s2424905x18500046 ◽

2018 ◽

Vol 03 (01) ◽

pp. 1850004 ◽

Cited By ~ 3

Author(s):

Lisandro Leon ◽

Frank M. Warren ◽

Jake J. Abbott

Keyword(s):

Cochlear Implant ◽

Magnetic Dipole ◽

Basilar Membrane ◽

Human Subjects ◽

Dipole Field ◽

Optimal Configuration ◽

Electrode Arrays ◽

Field Source ◽

Magnetic Dipole Field

Magnetic guidance of cochlear-implant electrode arrays during insertion has been demonstrated in vitro to reduce insertion forces, which is believed to be correlated to a reduction in trauma. In those prior studies, the magnetic dipole-field source (MDS) was configured to travel on a path that would be coincident with the cochlea’s modiolar axis, which was an unnecessary constraint that was useful to demonstrate feasibility. In this paper, we determine the optimal configuration (size and location) of a spherical-permanent-magnet MDS needed to accomplish guided insertions with a 100[Formula: see text]mT field strength required at the cochlea, and we provide a methodology to perform such an optimization more generally. Based on computed-tomography scans of 30 human subjects, the MDS should be lateral-to and slightly anterior-to the cochlea with an approximate radius (mean and standard deviation across subjects) of 64[Formula: see text]mm and 4.5[Formula: see text]mm, respectively. We compare these results to the modiolar configuration and find that the volume of the MDS can be reduced by a factor of five with a 43% reduction in its radius by moving it to the optimal location. We conservatively estimate that the magnetic forces generated by the optimal configuration are two orders of magnitude below the threshold needed to puncture the basilar membrane. Although subject-specific optimal configurations are computed in this paper, a one-size-fits-all version with a radius of approximately 75[Formula: see text]mm is more robust to registration error and likely more practical. Finally, we explain how to translate the results obtained to an electromagnetic MDS.

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