Telerobot-assisted laparoscopic adrenalectomy: feasibility study

The advent of fifth-generation (5G) wireless network technology has provided a boost to network support for telesurgery, bringing this form of treatment into reality. This technology has improved the possibility of performing telesurgery, which has been attempted in, among others, ophthalmology, neurosurgery, cardiovascular surgery, and orthopaedics1–4. These attempts were, however, more focused on telementoring or telepositioning, which do not involve continuous manoeuvres, so they do not really reflect relatively complex treatment modalities like laparoscopic surgery. Based on a series of animal experiments5,6, the aim of this study was to evaluate the safety and feasibility of remote robot-assisted laparoscopic adrenalectomy over a 5G wireless network. Detailed methods are available in Fig. 1 and Appendices S1 and S2. A urologist from the Affiliated Hospital of Qingdao University in Qingdao, China, performed telerobotic-assisted laparoscopic adrenalectomy over a 5G wireless network to treat patients with adrenal tumours who had been recruited from three other primary hospitals in different towns of Shandong Province. These were located 82.5, 199, and 250 km away from the Affiliated Hospital of Qingdao University (Fig. S1). All major surgical steps, such as delicate dissection, cauterization, and sectioning, were performed remotely by the urologist. Equipment and network for telerobot-assisted laparoscopic adrenalectomy The urologist from the Affiliated Hospital of Qingdao University in Qingdao, China, performed telerobot-assisted laparoscopic adrenalectomy by operating the master unit according to the video displayed on the screen. The urologist’s manipulation created electrical impulses, and this information was digitalized and translated into packets that commanded the slave arms and the instruments (effectors) attached to them by the processor of the master unit. (1) The fifth-generation (5G) customer premises equipment (CPE) received the operating stream generated by the master unit through the indoor fibre-optic cable connection (2, a), and converted it into a wireless signal (2, b). (2) The 5G base station around Qingdao received the operational signal sent from the 5G CPE and transmitted it stepwise to the 5G base stations near the hospitals where the patients were located. (3) The 5G network signal transmission (including video signal and operational signal) during the operations was maintained and guaranteed by the 5G core network as a priority. (4) The 5G base stations near the hospitals where the patients were located received the operational signal and transmitted it to the 5G CPE (5, a), which converted the signal into an operational stream and transmitted it to the slave cart through the indoor fibre-optic cable connection (5, b). (5) The patient side cart translated the operational commands from the master unit into the corresponding actions of the slave arms and the effectors to perform telesurgery on the patients (6, a). The laparoscopic camera on the slave unit (6, a) captured the view of the surgical field (6, b) and presented it in real time on the display screen for observation by the surgical assistants (6, c). (6) The same image of the surgical field as on the display screen was converted into a video stream by the patient side cart and delivered by the indoor fibre-optic cable to the 5G CPE (7, a) which then converted the stream into a video signal and sent it to the 5G base stations (7, b). (7) The 5G base station near the hospitals where the patients were located received the operational signal sent from the 5G CPE and transmitted it stepwise to the 5G base station around Qingdao. (8) The 5G base station around Qingdao received the video signal and transmitted it to the 5G CPE (9, a), which converted the signal into a video stream and transmitted it to the screen of the master unit through the indoor fibre-optic cable connection (9, b). (9) During the telesurgery, the surgeon maintained verbal contact with the assistant via a mobile phone with bluetooth headsets (10, a). There were video cameras at each site providing video feedback on a large television screen to ensure that staff on both sides had visual contact (10, b). (10) Internet firewalls were built at the endpoints of each 5G network to ensure the security and privacy of data transmission. (11) During operation, special software (12, a) was used to monitor the network quality in real time, based on the feedback values from the Packet Internet Groper (Ping) command. Network fluctuations, network latency, and the number/rate of lost packets were also displayed on the software’s interface. At the end of the operation, the software calculated and analysed the average latency during the whole operation. A screenshot of the software's interface at a given moment is shown in (12, b). (12) A cable network connectivity scheme (13, a) and technical engineers (13, b) served as the final safeguard in network security. The telerobot system used in the study was the MicroHand S surgical robot® (WEGO Surgical Robot Company, Weihai, China), which consists of a surgeon’s console (master unit) and patient side cart (slave unit)5–9. The two physically separate subsystems were connected through a 5G wireless network (China Mobile Communications Group Company) (Fig. 1 and Table S1). The study was registered on the clinical trials website (https://clinicaltrials.gov/) under registration numbers NCT04570176 and NCT04804163, and was reviewed by the Academic Committee and Ethics Committee of the Affiliated Hospital of Qingdao University (QYFYEC 2020-012-01). Each participating hospital approved the study protocol, patient information form, and informed consent forms. Patients with adrenal tumours that were hormonally active or had grown more than 1 cm during annual evaluation were recruited. All study participants were informed about the novelty of this approach, and provided written informed consent specific for the remote robot-assisted laparoscopic adrenalectomy (Fig. S5). The success rate of operations was the primary endpoint of whether the telesurgeries were feasible and safe. Feasibility was defined as having all operations of the telesurgery performed under the remote control of the attending surgeon without a forced conversion to open surgery or other non-telesurgery forms of laparoscopic surgery. Safety was defined by a patient having a Clavien–Dindo complication grade of less than III at discharge10, meaning the absence of any complications that were likely to result in permanent damage to the organ, or complications requiring surgical intervention and/or causing death. Any event that did not fall within these definitions of feasibility and safety was considered to represent a failure of telesurgery. Secondary endpoints included duration of teleoperation, blood loss, occurrence of adverse events, pain score on a visual analogue scale (VAS) during the first 24 h after surgery11, and outcomes 30 days and 6 months after operation. All adverse events that occurred during operation were recorded in detail. The National Aeronautics and Space Administration Task Load Index (NASA-TLX) scale was used for subjective evaluation of the intraoperative workload of the surgeon12, with higher scores indicating heavier workloads. In addition, evaluation of the intraoperative network communication was dependent on signal transmission distance, network latency, and packet loss. Details are available in Table 1, Figs S2–S4, Tables S2–S4, Appendix S3, and Video S1. Fifteen participants were enrolled in the study between February and April 2021. Among these patients, the success rate of the procedures was 100 per cent. All key parts of the operations were performed by the urologist remotely operating the surgical robot in Qingdao. The vital signs of patients were stable during the whole procedure. By the time of discharge from the hospital, all 15 patients had a Clavien–Dindo grade of I, signifying no serious complications requiring medical intervention. They all recovered successfully, and had no obvious complications or significant abnormalities as determined by laboratory tests or CT at postoperative follow-up. Detailed intraoperative network communication and surgical outcomes of telerobot-assisted laparoscopic adrenalectomy The total latency (tl) includes network latency (nl) and the time for the robot system to process the signal (tr): tl = tr + nl. The tr was approximately 150 ms, including the servo period of the surgical robot (less than 1 ms), the mechanical response delay of the robot (40 ms), endoscopic imaging, image processing delay (50 ms), and the video codec delay (60 ms). NASA-TLX, National Aeronautics and Space Administration Task Load Index; VAS, visual analogue scale. Detailed intraoperative network communication and surgical outcomes of telerobot-assisted laparoscopic adrenalectomy The total latency (tl) includes network latency (nl) and the time for the robot system to process the signal (tr): tl = tr + nl. The tr was approximately 150 ms, including the servo period of the surgical robot (less than 1 ms), the mechanical response delay of the robot (40 ms), endoscopic imaging, image processing delay (50 ms), and the video codec delay (60 ms). NASA-TLX, National Aeronautics and Space Administration Task Load Index; VAS, visual analogue scale. A total of six adverse events occurred during the operations. All were recorded, and all were associated with fluctuations in the wireless network, when instantaneous latency increased leading to a brief desynchronization between master handles and slave arms. Each time this lasted approximately 30 s, after which the malfunction automatically repaired itself and did not cause any other adverse effects. This feasibility study presents a novel application of 5G technology in the field of robot-assisted telesurgery. The encouraging results show that the combination of 5G technology with telerobot-assisted laparoscopic adrenalectomy is safe and feasible. The study, however, has certain limitations. To ensure the safety of patients to the greatest extent, the research team took many measures to tackle any emergencies that may occur during the operations. For example, a high network priority and large amount of technical personnel were devoted to ensuring a stable wireless network, and a wired network system was prepared as the alternative plan in case the wireless network was interrupted. Surgically experienced urologists were also selected to be assistants, and these had the competence to convert to conventional laparoscopic surgery in the event of a serious adverse event. Although none of the above contingency options were used in the study, it is undeniable that these back-up plans would not be possible in resource-limited areas. In addition, the patients selected were all in good physical condition and had no history of abdominal surgery (Fig. S5); to reduce the difficulty of teleoperation, the only surgical procedure involved in this study was adrenalectomy, in which the surgical manoeuvres were relatively simple and uncomplicated (Appendix S2). These factors definitely improved the chance of a successful procedure. Therefore, the universal general applicability of 5G-based remote robotic laparoscopic surgery is still the subject of debate. Furthermore, there is a lack of legislation, marketing, and ethical policies normalizing this new technology. To facilitate its implementation, there still are barriers to overcome. Despite these limitations, in the context of the uneven distribution of medical resources worldwide13,14, this novel technology could potentially provide patients in resource-limited regions more options for accessing high-quality care15,16, and could provide care for the wounded in extreme environments such as natural disasters or during war17,18. It can be further envisioned that, if the telesurgical paradigm becomes popular around the world, such patients may benefit the most. This may lead to innovation and changes in the pattern of healthcare. With further development of science and technology, and with the establishment of hierarchical medical systems, more regions could be covered by a stable 5G wireless network signal, and thus surgical robots will gradually be utilized. Moreover, surgeons in the primary hospitals would becoming increasingly capable of functioning as remote surgical assistants. All these factors could contribute to the establishment of remote telesurgery to the benefit of many more patients. This work was supported by the National Natural Science Foundation of China (52122501), the Major Scientific and Technological Innovation Project of Shandong Province (2019JZZY021002), Qingdao People’s Life Science and Technology Project (18-6-1-64-nsh), and the Taishan Scholar Program of Shandong Province (tsqn20161077). J.L.,W.J., and H.Y. contributed equally to this work. The authors declare no conflict of interest. Supplementary material is available at BJS online.