Preclinical evaluation of the Versius surgical system: A next‐generation surgical robot for use in minimal access prostate surgery

Abstract Objectives To evaluate the Versius surgical system for robot‐assisted prostatectomy in a preclinical cadaveric model using varying system setups and collect surgeon feedback on the performance of the system and instruments, in line with IDEAL‐D recommendations. Materials and methods Procedures were performed in cadaveric specimens by consultant urological surgeons to evaluate system performance in completing the surgical steps required for a prostatectomy. Procedures were conducted using either a 3‐arm or 4‐arm bedside unit (BSU) setup. Optimal port placements and BSU layouts were determined and surgeon feedback collected. Procedure success was defined as the satisfactory completion of all steps of the procedure, according to the operating surgeon. Results All four prostatectomies were successfully completed; two were completed with a 3‐arm BSU setup and two using a 4‐arm BSU setup. Small adjustments were made to the port and BSU positioning, according to surgeon preference, in order to complete the surgical steps. The surgeons noted some instrument difficulties with the Monopolar Curved Scissor tip and the Needle Holders, which were subsequently refined between the first and second sessions of the study, in line with surgeon feedback. Three cystectomies were also successfully completed, demonstrating the capability of the system to perform additional urological procedures. Conclusions This study provides a preclinical assessment of a next‐generation surgical robot for prostatectomies. All procedures were completed successfully, and port and BSU positions were validated, thus supporting the progression of the system to further clinical development according to the IDEAL‐D framework.


| INTRODUCTION
Minimal access surgery (MAS) has been utilised in urological surgeries for several decades and is well established in prostate procedures. 1,2 Prostatectomy by MAS offers significant benefits over open surgery with shorter catheterisation time, less blood loss, less post-operative pain, shorter hospital stay and recovery, lower rates of complications and comparable oncological outcomes. 3,4 However, MAS is associated with certain limitations, such as a lack of ergonomically designed surgical instruments, restricted reach and access of instruments, limited haptic feedback and the lack of depth perception resulting from twodimensional visualisation. 5 Ultimately, such limitations can lead to an extensive learning curve for surgeons. 6,7 Additionally, during MAS procedures, surgeons often experience muscular strains and fatigue resulting from asymmetric static positioning and hunched postures. 5,8 These physical burdens are exacerbated by the technically challenging nature of urological procedures, where the surgeon must operate in a parallel axis to the pelvis. 5 Robotic assistance in MAS may overcome some of the challenges associated with conventional MAS, retaining the advantages of a minimally invasive approach but often with greater technical ease and a shallower learning curve. 9 Robotic systems can offer an enhanced three-dimensional view, increased magnification of the surgical field, improved manual dexterity within the confines of the pelvis, tremor filtration and improved ergonomics. 6 These advantages can reduce the learning curve associated with MAS, thus increasing the accessibility of MAS and enabling surgeons to perform more complex urological procedures. 10,11 Moreover, implementation of robotic systems in urological procedures could improve the management of prostate cancer, enabling the development of several techniques (including nerve-sparing techniques) that improve functional and oncological outcomes. 12,13 Despite these significant advantages, there is scope for improvement in robotic systems, on account of the increased use of operating room (OR) space, possibility of equipment malfunction, initial learning curve, training of medical personnel and high costs of purchase and maintenance. 14,15 The Versius surgical system (CMR Surgical, Cambridge, UK) is a tele-operated robotic surgical system developed for use in MAS. 16 The device was developed with the aim of improving surgical outcomes for patients and to better meet the needs of surgeons; its design was refined iteratively according to end-user feedback from surgeons. 17 The system comprises a surgeon console with hand controllers and a head-up display (HUD), a visualisation bedside unit (BSU) with an endoscopic camera, and up to four instrument BSUs. The HUD provides the surgeon with a three-dimensional, high-definition visual from the endoscopic camera. 16,17 The open console design of the device enables ease of communication between surgeons and their teams throughout surgical procedures, while also providing flexibility with a seated or standing operating position. The device is operated by hand controllers, which are ergonomically designed in the style of a 'game controller' and can accommodate a range of hand sizes. 16,17 The device instruments mimic the articulation of the human arm, which, together with the wristed joint of the instruments, provides seven degrees of freedom at the instrument tip, enabling greater surgical access compared with conventional MAS. 16,17 Development of a fenestrated bipolar device and an energy sealer device for this robotic system is currently ongoing. Additionally, the compact and mobile BSUs allow the system to be used within standard ORs and easily moved between ORs for maximum flexibility. 16,17 The IDEAL-D (Idea, Development, Exploration, Assessment, Long-term study-Devices) framework provides recommendations for generating a detailed evidence base throughout the medical device development process. [18][19][20] Previous studies have provided evidence of the development and operational safety of the system, according to Stage 0. 16,17 Preclinical studies have provided proof of concept for the use of the device in a range of procedures for gynaecology, renal and urology, and general and colorectal surgery (Stage 1). [21][22][23][24] These studies have supported continuation to in-human clinical trials of the surgical robot in hysterectomy and cholecystectomy surgeries, 25,26 and implementation in other surgical specialties is ongoing (Stage 2).
The preclinical study described herein aimed to evaluate the suitability of the device for use in prostatectomies, in line with the IDEAL-D framework (Stage 1). The primary objective was to evaluate the use of the system in completing the surgical steps required for a prostatectomy using either a 3-arm or 4-arm BSU setup in a preclinical cadaveric model. Secondary objectives were to determine the optimum port placements and BSU layouts for a prostatectomy using F I G U R E 1 Grid used to record port and BSU positions. A grid of 20 cm Â 20 cm squares was laid out on the OR floor (overall grid was 320 cm Â 320 cm) to ensure standardised and reliable reporting of measurements. Pink circle indicates the umbilicus (where the midline crosses the supine-umbilical line). BSU, bedside Unit; OR, operating room. either a 3-arm or 4-arm BSU setup and collect surgeon feedback on the performance of the system and instruments.

| MATERIALS AND METHODS
All cadaver procedures were conducted at The Evelyn Cambridge Surgical Training Centre, Cambridge, UK. All cadavers were donated with consent.
The first session of the study was conducted in July 2020 and included the 3-arm setup procedures, and the 4-arm setup procedures were performed in a second session in December 2020. The initial F I G U R E 2 Port placements for prostatectomy using either a 3-arm or 4-arm BSU setup. a Abdomen insufflated to 12 mmHg. b 4 cm from anterior superior iliac spine. BSU, bedside unit; ML, midline; MCL, midclavicular line; SUL, supine umbilical line.
T A B L E 1 Summary of procedures performed using either a 3-arm or 4-arm BSU setup and successful completion.

| RESULTS
The cadavers represented body mass indices (BMIs) ranging from 24.3 to 32.0 kg/m 2 (mean: 27.0 kg/m 2 ). Four prostatectomies were performed, the surgical steps of which are outlined in Online Resource 2.
Three cystectomies were also performed to demonstrate the ability of the system to perform additional urological procedures; the surgical steps for these procedures are outlined in Online Resource 3. All eight procedures were successfully completed (Table 1). Of these, two prostatectomies and one cystectomy were performed with a 3-arm BSU setup. The other two prostatectomies and two cystectomies were performed using a 4-arm BSU setup.
During the prostatectomies performed using a 3-arm BSU setup, the port positioning was effective and all surgical steps were completed without any adjustment. The BSU positioning required minor adjustments. In one procedure, the visualisation BSU was exchanged with a replacement to avoid delays following a system alarm (caused by high pressure levels between the endoscope and operating trocar).
Throughout the prostatectomies performed using a 4-arm BSU setup the port positioning required no adjustments to complete the surgical steps; however, the initial port placement was further lateral in the second procedure to compensate for the increased BMI. In the early stages of the first procedure, the positioning of the BSU was adjusted following instrument arm clashes that generated two medium-priority alarms. Later in this procedure, the BSU setup was changed from two on the left and two on the right to three on the left and one on the right side, in order to allow greater access for the surgical assistant (this placement was also carried over into the second procedure). Minor adjustments to BSU positioning were needed during the second 4-arm setup prostatectomy, once the BSUs were brought closer to the operating table to accommodate the larger BMI.  The port positioning configurations and BSU positioning used by the surgeons during the cystectomy procedures for the 3-arm and 4-arm BSU setups are shown in Figures 5 and 6, respectively.
Having successfully met the primary objective, surgeon feedback was also collected as part of the secondary objectives. One of the lead surgeons observed that

| CONCLUSION
This study provides a preclinical assessment of