First Study in Men Evaluating a Surgical Robotic Tool Providing Autonomous Inner Ear Access for Cochlear Implantation

Abstract

Image-guided and robot-assisted surgeries have found their applications in skullbase surgery. Technological improvements in terms of accuracy also opened new opportunities for robotically-assisted cochlear implantation surgery (RACIS). The HEARO® robotic system is an otological next-generation surgical robot to assist the surgeon. It first provides software-defined spatial boundaries for orientation and reference information to anatomical structures during otological and neurosurgical procedures. Second, it executes a preplanned drill trajectory through the temporal bone. Here, we report how safe the HEARO procedure can provide an autonomous minimally invasive inner ear access and the efficiency of this access to subsequently insert the electrode array during cochlear implantation. In 22 out of 25 included patients, the surgeon was able to complete the HEARO® procedure. The dedicated planning software (OTOPLAN®) allowed the surgeon to reconstruct a three-dimensional representation of all the relevant anatomical structures, designate the target on the cochlea, i.e., the round window, and plan the safest trajectory to reach it. This trajectory accommodated the safety distance to the critical structures while minimizing the insertion angles. A minimal distance of 0.4 and 0.3 mm was planned to facial nerve and chorda tympani, respectively. Intraoperative cone-beam CT supported safe passage for the 22 HEARO® procedures. The intraoperative accuracy analysis reported the following mean errors: 0.182 mm to target, 0.117 mm to facial nerve, and 0.107 mm to chorda tympani. This study demonstrates that microsurgical robotic technology can be used in different anatomical variations, even including a case of inner ear anomalies, with the geometrically correct keyhole to access to the inner ear. Future perspectives in RACIS may focus on improving intraoperative imaging, automated segmentation and trajectory, robotic insertion with controlled speed, and haptic feedback. This study [Experimental Antwerp robotic research otological surgery (EAR2OS) and Antwerp Robotic cochlear implantation (25 refers to 25 cases) (ARCI25)] was registered at clinicalTrials.gov under identifier NCT03746613 and NCT04102215.

Clinical trial registration: https://www.clinicaltrials.gov, Identifier: NCT04102215.

Keywords: HEARO procedure; cochlear implantation; image-guided surgery; robotically-assisted cochlear implantation surgery; sensorineural hearing loss (SNHL).

Conflict of interest statement

MM was an employee and shareholder of CASCINATION AG. MZ-A and PG were employees of MED-EL Medical Electronics. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Topsakal, Heuninck, Matulic, Tekin, Mertens, Van Rompaey, Galeazzi, Zoka-Assadi and van de Heyning.

Figures

Figure 1

The HEARO® robotic system. (1) Robot mount, (2) headrest, (3) patient marker attachment, (4) patient marker, (5) drill, and (6) drill mount with force/torque sensor.

Figure 2

The HEARO procedure for cochlear implantation surgery. (1) Scanning and planning, (2) performing middle ear access with cutting bur, (3) performing inner ear access with diamond bur, (4) placement of array through a removable insertion tube, and (5) postoperative scanning and quality analysis.

Figure 3

Endoscopic view of the partial canonostomy. An example of the endoscopic view of the canonus (A) and the round window (RW) niche (B) on the left side. The right side shows a partial canonectomy (C) during intraoperative surgical check.

Figure 4

Illustration of the inner ear access of the HEARO. The distance between point lateral wall (LW) and medial wall (MW) represents the bone thickness of the inner ear access point. The red rectangle under the graph also represents the thickness of the bony wall. The white solid line on the graph defines the target point set by the user at the preoperative planning stage. The filled blue line represents the force transients and the exact force at each specific point and is also displayed inside the burr illustration under the graph. The dashed white line represents the estimated point at which the size of 0.9 mm for the opening is achieved.

Figure 5

Patient selection and demographics.

Figure 6

Retroauricular incision. Left side is one of the first 3 cases (initial EAR2OS trial) and right side all other more recent cases (ARCI25 trial).

Figure 7

Insertion status.