Since the beginning of robotic surgery, pioneers and researchers have dreamed of performing surgery across great distances. In the latter half of the twentieth century, NASA and the US military began researching the development of new technologies for surgeons away from hazardous environments [1].
Initial advances in teleoperated systems gave way to the PUMA 200 robot for CT-guided brain biopsies in 1985 [2]. A major breakthrough came with the ZEUS robotic system, which was approved for general surgery in 1998 [2]. Development continued and in 2000 the Da Vinci Surgical System (Intuitive Surgical, Sunnyvale, CA) was launched [2].
Advances in technology have paved the way for the inclusion of telemedicine in surgery. These advances began with telepresence, where the remote operation site is presented naturally, resulting in the feeling of presence [3]. Research continued to demonstrate the effectiveness of telementoring, in which an experienced surgeon can “guide” a trainee through a procedure, using telecommunications technology [4].
Finally, compared to telepresence and telementoring, remote telesurgery is where a primary surgeon operates on a patient located at a distance. Although the fundamental hardware elements necessary for remote telesurgery exist, the clinical field of remote surgery remains in its infancy. This systematic review focuses on published applications of remote telesurgery in humans.
| Methods |
A systematic review of all available English-language literature was conducted to evaluate clinical experiences in remote telesurgery in humans. PubMed, EMbase, Inspec & Compendex, and Web of Science were consulted on August 2, 2021, searching for articles containing the keywords: telesurgery , remote telesurgery , long-distance surgery . long distance) , and telerobotics (telerrobotics).
The following inclusion criteria were used to select the articles:
(1) the subjects in the cases had to be humans (living patients or cadavers);
(2) the operating surgeon and the patient had to be in different locations, separated by more than 1 kilometer;
(3) that outside physician had to be the primary surgeon on the case; and
(4) the article had to explicitly report the use of a remote telerobotic technique.
The following exclusion criteria were used:
(1) articles that exclusively contained animal experiments; and
(2) articles that were focused on telepresence or telementoring.
No systematic reviews or meta-analyses were included in this study. Article titles and abstracts were reviewed for relevance based on the inclusion criteria. The references of each article were checked to locate relevant studies, and to identify articles considered eligible, and the full-text manuscripts were reviewed. Two authors independently reviewed each article at each stage, and disagreements were resolved by mutual discussion.
| Results |
The initial database search returned 2339 articles after removing duplicates. Two reviewers independently identified 24 articles that potentially met the inclusion criteria, and these were then searched through the full text.
Sixteen articles were excluded due to lack of original content, focus on experimental procedures, or proximity of the primary surgeon to the patient site. Eight articles qualified for inclusion in the systematic review, spanning from 2001 to 2020.
The first article was in 2001, when Bauer et al. described a renal access procedure in which the operating surgeon was in Baltimore, Maryland, while the patient was more than 7000 kilometers away in Rome, Italy [5]. Using a PAKY ( percutaneous access of the kidney ) robot, connected to a simple old telephone system line, they were able to successfully obtain percutaneous access in less than 20 minutes. Signal latency was not measured or reported.
In 2002, Marescaux et al. reported the first robotically assisted transatlantic laparoscopic cholecystectomy, in a case known as the “Lindberg Operation” [6]. The operating surgeon and the robotic surgical system (ZEUS, Computer Motion, California) were connected via a high-speed terrestrial fiber optic network (France Telecom/Equant). That is the longest surgical procedure published, with approximately 14,000 km of distance, and they reported a total time delay of 155 ms. The procedure was completed in 54 min, without any complications.
In 2005, Anvari et al. explored the role of telerobotic remote surgery in 21 cases performed between McMaster University, Hamilton, Ontario , and North Bay General Hospital , Northern Ontario, Canada [7]. The surgeons performed these laparoscopic operations between February and December 2003, using the ZEUS TS microjoint system (Computer Motion, California), connected to a virtual private network Internet protocol. The round trip delay varied between 135 and 140 ms, and there were no major intraoperative complications.
Anvari later reported 22 additional cases occurring on the same network between McMaster University and Northern Ontario General Hospital . The reported time delay ranged from 135 to 150 ms, but it was noted that latency above 200 ms requires the surgeon to slow down to avoid overshoot[8].
Tian et al. described the use of long-distance telerobotic surgery in cardiology. The group reported five percutaneous coronary artery interventions with telerobotic assistance, performed at a distance of 32 km [10]. Using a CorPath GRX robotic system (Corindus Robotics, Waltham, MA, USA), the procedures were performed without complications, with an observed time delay of 53 ms.
The final two articles included in this review involved a connection using 5G networks. Tian et al. connected to a 5G network (China Telecom and Huawei Technologies Co, Ltd.) and reported no network delay or intraoperative adverse events [11]. Acemoglu et al. performed a laser microsurgical procedure on a cadaver, using a new surgical robot connected to the 5G Radio Access Network . At 15 km distance, those authors reported a maximum round trip latency of 280 ms [13].
| Discussion |
Telerobotic remote surgery, although pioneered more than two decades ago, is still in its infancy.
Concerns about security, cost, and latency have limited the growth and pursuit of remote telesurgery. Previous reviews have evaluated the status of robotic surgery, its adoption across surgical specialties, and its potential use in remote surgical settings, but none have focused on purely clinical applications [3,13]. Including three manuscripts published since those contemporary reviews, the authors found only 8 peer-reviewed articles reporting a total of 73 cases of telerobotic surgery.
Various robotic platforms have been used for human telesurgery. The most published experience comes from the Zeus platform. As ubiquitous as the Da Vinci platform is in current clinical use, it has not been employed for remote human telesurgery.
A variety of signal communication methods have been employed, and the recent trend is to use a 5G network. Efforts describing technical methods after the historic Operation Lindberg were valuable [14], but there remains a great opportunity to describe, optimize, and standardize modern communication methods. Interestingly, the highest signal latency (280 ms) in this review was reported when a 5G network was used over 15 km distance.
The 5G network is a complex set of data transactions across local devices and national telecommunications service providers. Ultimately, throughput and latency will depend on the weakest part of the transaction chain between the local and remote site. Since 5G is a short-range data transmission protocol, the infrastructure to realize a full 5G network over a large geographical area is enormous and therefore realizing a network of any significant distance running solely on 5G would be unrealistic. short-term as a service; providers would invariably force traffic routes through older infrastructure.
Additionally, service providers have full control of bandwidth allocation and although priority levels are typically assigned to divide the available bandwidth for all traffic (i.e. military networks have high priority while residential have low priority), those priorities are negotiated by the government and each telecommunications provider, and a similar commitment for telemedicine priorities would imply significant national pressure on telecommunications corporations. Meanwhile, you could imagine that you simply wouldn’t have such a consistently stable transmission, resulting in larger latencies and variability of those latencies.
It is well established that latency causes significant impairment in task performance, but there is no consensus on what is a safe or acceptable amount of signal latency for remote telerobotic surgeries. There are more errors and tasks take longer when surgeons work under delayed conditions [15,20]. Latencies below 200 ms may be ideal [21], but deterioration has been reported at 135 ms [22], and even with time delays as small as 50 ms [23,24].
Although successful robotic telesurgery with a latency of 450 to 900 ms has been reported [17], surgery with a latency greater than 700 ms may not be feasible [21,25]. Beyond work on basic models of surgical tasks [20], there is a need to analyze performance with more clinically relevant robotic surgery tasks over time delay. Unfortunately, latency is not well characterized in the preclinical and clinical telesurgery literature.
Future studies should recognize that signal latency is not static, and that it changes over the course of a procedure. Most telesurgery publications only measure mean/average signal latency. Variance, or the degree of delay time fluctuations, is never mentioned, nor is its impact on a surgery.
In 2003, Butner and Ghodoussi emphasized that “because human life is at stake, issues related to safety, error detection, and fail-safe operation are of great importance” in robotic telesurgery. [14]. Security is directly related to signal latency issues, and the authors believe it is the main barrier to the growth of remote telesurgery.
Haptic feedback [26], augmented reality predictive display [27], and compensatory motion scaling [20] have been shown to improve surgical performance in experimental models, but there is a paucity of work aimed at combating latency. the signal. To date, there are no clinical studies of remote telerobotic surgery testing potentially safe interventions.
There are several other key barriers to remote telesurgery that deserve careful consideration, but are outside the scope of this work. These include things like challenges with localization and mapping, and optimizing signal transmission. The approval process for robotic telesurgery technologies also remains to be defined, since this is a new area.
Future work in remote telesurgery is needed to better understand latency parameters, and design and test technologies aimed at ensuring safety. Beyond that mandatory benchmark for safety, there is much work to be done in surgeon and equipment training, cost and value management, risk mitigation, and medico-legal arenas.
Transparent and honest methods should be followed when approaching remote telesurgery studies. There are some guidelines established by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), which advise that telerobotic surgery be performed under strict supervision of the Institutional Review Board, with careful design and methodology [28].
The authors hope that this summary of the current experience of clinical telesurgery, and discussion of key limitations and technical considerations, will increase momentum in this exciting field of research. Millions of future patients will benefit from the expanded capabilities of robotic surgery.
| Conclusions |
Remote telerobotic surgery is a long-awaited but still nascent capability. Reports have emerged showing this new technology, with encouraging results. However, none of the work, to date, has presented efforts to combat signal latency, and strong security remains a critical and yet untested benchmark.
A low-key approach is necessary for future studies in remote robotic surgery, to realize its potential and adequately address existing questions about safety and feasibility. Quality studies that take these limitations into account can advance robotic surgical practice, and have far-reaching implications spanning multiple surgical specialties.
