<scp>Pre‐Clinical</scp> Experience With the <scp>VITOM 3D</scp> and the <scp>ARTip</scp> Cruise System for <scp>Micro‐Laryngeal</scp> Surgery

Abstract

Three-dimensional exoscopic technology has been recently introduced in the clinical practice and is becoming increasingly popular among several surgical specialties, such as reconstructive microsurgery, with promising preliminary results.1-6 The Karl Storz company (Tuttlingen, Germany) has introduced the VITOM® 3D exoscope, which is a video system conjugating a 4 K HD resolution view with a three-dimensional technology. Images are displayed on a flat screen and the 3D vision is obtained using dedicated glasses. The 3D camera, which provides a magnification power of 8-30x and a depth of field between 7 and 44 mm, is held in place by a supporting arm and allows for a focal distance of 20–50 cm. Thanks to these features, the VITOM® 3D exoscope could be potentially used in substitution to the conventional operating microscope.2 In this preclinical study we had the chance to preview the robotic ARTip™ cruise robotic system, which is a cart-based robotic holding arm controlled using the standard VITOM® 3D joystick (IMAGE 1 pilot) and a foot-pedal. It can be used to move the exoscope in all directions with high precision. The system will be available on the market in 2020. The aim of this prospective pilot study was to evaluate the feasibility of the “Exolaryngoscopic” surgery using the VITOM® 3D exoscope and the ARTip™ cruise robotic system. The Institutional Ethics Committee of Humanitas Clinical and Research Centre exempted the prospective study from the evaluation since no humans/animals were involved. On December 15th 2019, a total of 10 consecutive procedures were performed using the VITOM® 3D-ARTip™ cruise system at ‘Mario Luzzatto’ Simulation Center of Humanitas University. Procedures were performed by 3 medical students, 4 ENT residents and 3 ENT specialists. All ENT specialists had previous experience of VITOM® 3D assisted surgery. All residents and students observed at least 10 cases of VITOM® 3D assisted surgery in a real clinical scenario, but they never used it. None in the sample had previous experience of the ARTip™ cruise robotic system. Prior to the simulation, each operator was instructed on the VITOM® 3D-ARTip™ cruise system by an expert technician, and had 5 minutes to familiarise themselves with the device. A silicon human-sized mannequin was placed on an operating bed in the Boyce position and the glottic plane was exposed using an operating laryngoscope (ref. 8590B, Karl Storz, Tuttlingen, Germany). A 30G spinal needle was introduced at the level of the anterior commissure and the tip was placed at the midline between the anterior and posterior commissure. The set-up of the simulation room is shown in Fig. 1. All operators performed the exercise (Fig. 2). The VITOM® 3D was positioned out of the surgical field in a standard position. The operators had to position the VITOM® 3D using the ARTip™ cruise robotic system at a distance of about 40 cm from the glottic plane. Once the image of the glottic plane image was correctly framed and enlarged, a 5 × 5 mm cottonoid had to be placed on the tip of the needle using a bouchayer-like forceps and then removed. A video of the procedure is shown in Video S1. Procedures time were recorded. After each procedure, the participants were asked to fill out a questionnaire on a 4-point Likert scale (1 - not acceptable, 2 - acceptable, 3 – good, 4 – very good). Ordinal variables were reported as counts and percentage, while the mean was reported for continuous variables. All procedures were successfully performed and sufficient surgical view was acquired in all cases. Mean positioning time was higher in medical students and residents (81.29 seconds and 57.96 seconds respectively) compared to ENT staff members (45.10 seconds), while mean procedure times where similar among the three groups (20.22 seconds, 21.92 seconds and 22.59 seconds respectively). All the data is summarised in Table 1. Table 2 shows the frequency of responses for each of the 11 survey items. “Not acceptable” was never chosen. Manoeuvrability of the ARTip™ cruise robotic system was considered “good” or “very good” in 70% of cases, while movement precision was considered “very good” in 90% of cases. Students, residents and ENT specialists were involved in this study in order to test the feasibility of micro-laryngeal surgery (MLS) using the VITOM® 3D-ARTip™ cruise system. The system was provided by the Karl Storz company and at the time of the pre-clinical study was still not on the market. All procedures were completed successfully without any delays or complaints. Nowadays VITOM® 3D is equipped with a holding arm named Versacrane™ (Karl Storz, Tuttlingen, Germany), which allows for exoscope orientation in all directions. The arm has mechanical joints and two hands are necessary to manipulate it in order to obtain the best orientation. For the current pre-clinical study we had the chance to preview the new ARTip™ cruise robotic system, which is a master-to-slave robotic holding arm. Compared to the Versacrane™, we appreciated many advantages. The ARTip™ cruise can be precisely moved controlling each degree-of-freedom individually (X, Y, Z, Pivot, Rotation) using only one hand that manipulates the IMAGE 1 PILOT, which is the same joystick used for VITOM® 3D optical settings. It is possible to switch between VITOM® 3D and the ARTip™ cruise control using a foot pedal. Manoeuvring is intuitive thanks to manual movements via direct drag mode. Setup of the system is easy and fast thanks to position presets, which memorises standard robotic arm positions. It is in fact possible to save and recall previous positions without directly touching the robotic arm. Mean positioning time of the VITOM® 3D-ARTip™ cruise system was only 61.1 seconds in first-time users. Although a comparison with a statistical analysis was not possible due to the small sample, we observed that students and residents collected higher positioning times (81.29 seconds and 57.96 seconds respectively) when compared with the ENT staff members (45.10 seconds). This could be explained with the fact that ENT staff had previous experience with the IMAGE 1 pilot joystick which is used for the VITOM® 3D optic settings in our routine practice. This also means that the potential gap between groups could be bridged after an appropriate training. Although the residents' and students' positioning times were higher, nobody judged the manoeuvrability as not acceptable and both groups judged the precision of movement as “very good” in 100% of cases (Table 2). On the other hand, students and residents collected overlapping procedure times when compared with ENT staff (overall mean 21.61 seconds). Moreover, we observed that VITOM® 3D general optic quality and ergonomics were judged “good” or “very good” by all subjects. This means that VITOM® 3D has value for surgery as already described in a previous paper.2 Since all the procedures were performed with the visual aid of the 3D monitor, all operators of the room have access to the same field of view. In a real clinical scenario this is potentially very useful for the scrubbed and assistant nurses who can directly observe the surgical field and anticipate the surgeon's next choice of instrument. This aspect also has an important impact on medical education. Residents and students can directly observe the same view as the first operator in 3D, which is not possible using a conventional 2D flat screen. Finally, it is possible to point out that the tested system has inherent advantages. First and foremost, the high movement precision, ergonomics, and the improved visualisation for all the surgical team. Further studies, including microscope comparison and cost-effectiveness investigations, with more representative samples and with real clinical scenarios are necessary in order to understand its real potential in clinical practice. Video S1. The video shows the exercise illustrated in Fig. 2. The operators had to position the VITOM® 3D using the ARTip™ cruise robotic system at a distance of about 40 cm from the glottic plane. Once the image of the glottic plane image was correctly framed and enlarged, a 5*5 mm cottonoid had to be placed on the tip of the needle using a bouchayer-like forceps and then removed. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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