Introduction
The global adoption of robotic surgery continues to rise in different surgical specialties like colorectal [
1‐
3], urology [
4,
5], bariatrics [
6‐
8], upper gastrointestinal [
9‐
11] and gynecology [
12‐
14]. While a large proportion of the robotic systems currently installed are the well-established da Vinci robotic surgical system (Intuitive Surgical Inc, California, USA), various manufacturers have developed and introduced alternative robotic systems. A few examples are the Revo-i (Meerecompany, Inc., Seongnam, Republic of Korea) [
15,
16], Senhance (formerly ALF-X) (Asensus Surgical, North Carolina, USA) [
17,
18], Versius (CMR Surgical, Cambridge, UK) [
19], Micro Hand S (Wego, Qingdao, China) [
20], Hugo
™ RAS (Medtronic, MN, USA) [
21,
22], and Hinotori
™ surgical robot system (Medicaroid Inc., Kobe, Japan) [
23,
24].
Most of these newer robotic surgical systems have been developed with distinctive capabilities such as haptic feedback, modular system, single port operating and implementation of artificial intelligence. In addition, there is also a target for a value-driven healthcare by reducing the device acquisition and ongoing operational cost. These are promising developments especially for ‘robot-naïve’ healthcare systems contemplating to adopt robotic surgical technologies.
Over the last few years, most publications on these novel robotic systems were early model development, preclinical results, feasibility studies and small case series. However, some centers have started publishing their results comparing these novel platforms to conventional laparoscopic approaches and even the da Vinci surgical system.
The aim of this study is to systematically review the existing literature on the clinical outcomes of these newer robotic surgical systems.
Methods
This systematic review of literature and meta-analysis was conducted in accordance to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines [
25]. No ethical approval was required. This systematic review was registered in The International Prospective Register of Systematic Reviews (PROSPERO) with the registration number CRD42023475626.
Electronic search
An electronic search was performed on the following databases: Embase, Medline, Pubmed, Cochrane library and Google Scholar independently by two reviewers on 1st May 2023. The search period was set from year 2012 to May 2023 to identify all published and indexed studies comparing clinical outcomes of newly developed multi-port soft tissue robotic surgical systems against laparoscopic (lap) or da Vinci (DV) robotic approach. A combination of “MeSH” and non- “MeSH” search terms: robotic surgery, robotic console, robotic surgical system, robotic surgical device, laparoscopic surgery, and laparoscopic procedure were used. A manual search of the reference lists of relevant studies was performed to identify additional studies.
Study selection
Two reviewers (Y.L., Z.M.) screened the studies independently to identify articles for potential inclusion. Studies were screened by their titles, abstracts, followed by their full texts. Any conflicts were resolved by consensus.
Studies were considered eligible for inclusion if patients were adult (18 \(\ge \) years old) undergoing robot-assisted soft tissue surgery using newly developed robotic surgical systems with clinical outcomes being compared against laparoscopic or da Vinci robotic approach. Only articles published in English were considered. Studies with insufficient outcome reporting, duplicated data, missing either a laparoscopic arm or da Vinci arm as comparison, case series or reports were excluded.
The primary outcomes of interest were clinical outcomes, including but not limited to the following: surgical complication rate: Clavien–Dindo grading (CD), length of stay (LOS), estimated blood loss (EBL), conversion rate being defined as conversion from the intended robotic approach to any other approaches or a different robotic platform, and standard oncological outcomes in cancer resection studies.
Data were extracted from studies that met the eligibility criteria. Parameters extracted included title, first author, year of publication, country where the study was conducted, study design, number of patients, patient characteristics, type of surgery and outcomes of interest.
Risk of bias assessment
The quality of the included studies was assessed by two reviewers independently using the Newcastle–Ottawa scale (NOS) for non-randomized studies [
26] or Jadad scale for randomized control trial (RCT) [
27].
Data analysis
Descriptive statistics were used to report patient and outcome data. A meta-analysis was not performed due to the heterogeneity of the procedures and reported clinical outcomes. A systematic narrative review was provided for each outcome.
Discussion
This systematic review examined 12 trials comprising of 1142 patients with the aim of evaluating the clinical outcomes of newly established multi-port robotic surgical systems. All studies included in this review were published in the last 3 years arising from Asia and Europe encompassing colorectal, urology and biliary procedures. Eight studies were head-to-head comparisons of novel robotic platforms: Micro Hand S, Senhance, Hugo
™ RAS, and KangDuo robotic systems against the da Vinci robotic platform. The outcomes between the novel robotic systems and Da Vinci robotic system were comparable. Three studies comparing the conventional laparoscopic approach with the robotic group demonstrated longer operative time [
35,
36] and lower EBL [
28,
34,
35] in the robotic group.
All 8 direct comparison studies between robotic platforms included in this review showed little difference in surgical outcomes in sigmoid colectomies, rectal resections, prostatectomy, pyeloplasty, partial nephrectomy and cholecystectomy. The newly developed robotic platforms had achieved a high level of technical capabilities and mechanical precision. This is especially true in procedures which rely on superior technical execution such as the TME studies showing > 70% of complete TME [
30,
35] and comparable clear resection margins in radical prostatectomy [
31,
39]. However, most of the studies consisted of carefully selected patient cohorts with low BMI, minimal comorbidities, and ASA scores less than 3. Therefore, the results may not be readily applicable to the general cohort of patients with high BMI or complex pathologies. These difficult surgical circumstances can be very challenging with conventional laparoscopic techniques even for experienced surgeons and may theoretically benefit from the superior ergonomics of robotic platforms.
Unsurprisingly, when compared against conventional laparoscopic approaches, the novel robotic systems (Senhance and Micro Hand S) showed longer operative time and lower blood loss volume. The longer operative time ranged from mean increase of 3 min to 30 min [
30,
34‐
36]. Interestingly, Kulis et al. reported a longer operative time in the first 30 cases and subsequently became shorter than the robotic group in the last 31 cases likely reflective of a steeper learning curve associated with the Senhance robotic platform consistent with a significantly higher conversion rate in the robotic group which the author attributed to the early learning curve [
34].
Longer operative time has been a point of contention against robotic surgery. The length of the surgical procedure is intricately related to the learning curve when adopting a new technique. Our review demonstrated a shorter operative time with the established laparoscopic and the da Vinci robotic platforms most likely due to the surgeons’ progression beyond the learning curve with standard laparoscopic tools and the da Vinci robotic platform. Hence, as the proceduralist obtains more experience with these emerging robotic platforms and progresses beyond the learning curve, operative time should decrease over time. One study suggested a 43-min reduction in operating time after 43 cases of robotic rectal surgery [
40] and Shaw et al. found a reduction in mean operating time of 53 min in robotic colorectal procedures after 15 cases, despite an increase in case complexity [
41]. Looking beyond the additional minutes spent in theater, proponents of robotic surgery would argue on the point of reduced days of hospital stay. For example, Wang et al. [
30] reported a mean reduction of 2.7 days in robotic TME versus laparoscopic TME. Similarly, Tewari et al.’s meta-analysis showed a mean reduction of 2.3 days in robotic versus laparoscopic prostatectomy [
42].
While this review was aimed to review literature over the last 10 years, all included articles were published within the last 3 years. This indicated that all the novel robotic systems were in a similar phase of clinical development likely secondary to the lapse of several key patents in 2019 owned by Intuitive Surgical Inc. which allowed other manufacturers to introduce their new robotic systems [
43]. Each new systems has been designed with different notable features (Tables
5,
6) to overcome the technical or cost constraints of the robotic platform. Furthermore, these are first generation and therefore further improvement, and optimization is expected. On the other hand, da Vinci had introduced 4 generations of their robotic system (2000/S/Si/Xi) with robust clinical data especially in the field of urology [
44].
Table 5
Comparison of different robotic systems
Manufacturer | Intuitive surgical | Wego | Asensus surgical | Meerecompany | Suzhou KangDuo robot | CMR surgical | Medtronic |
Optics | 12 mm, 3D | 10 mm, 3D, HD | 10 mm, 3D, HD | 10 mm, 3D HD | 10 mm, 3D, HD | 10 mm, 3D, HD | 10 mm, 3D, HD |
Console/workstation | Closed | Open | Open | Closed | Open | Open | Open |
Surgeon control | Finger grip, foot pedals | Finger grip, foot pedals | Laparoscopic style handles, footswitch activation | Finger grip, foot pedals | Finger grip, foot pedals | Joystick hand controls | Pistol-like handle, foot pedals |
Patient console | 4-armed operation cart | 3-armed operation cart | 4 separate modular arms | 4-armed operation cart | 3-armed operation cart | 3–7 separate modular arms | 3–4 separate modular arms |
Effector arm diameter | 8.4 mm | 10 mm | 3–10 mm | 7.4 mm | 10 mm | 5 mm | 8 mm |
Notable features | Endowrist technology | Virtual haptic feedback | Eye-tracking camera, haptic feedback, instrument compatible with standard laparoscopic trocars, no direct docking required | Collision warning messages | Remote surgery via 5G (wired connection) | Haptic feedback, instrument compatible with standard laparoscopic trocars, small footprint, ergonomic console (sitting or standing position), ability to operate in 2 fields | Head tracking, haptic feedback, tilt function on effector arm |
Effector arm service life | 10 uses | Undisclosed | Reusable | 20 uses | 10 uses | 13 uses | 15 uses |
Cost of device* | USD 1.5–2 million | Undisclosed | USD 1.3 million | Undisclosed | Undisclosed | USD 1.8-2million | USD 2.5 million |
Table 6
Illustrations of the various robotic platforms
Currently, the cost of robotic surgery remains a major barrier to widespread implementation [
45‐
47], particularly in low and middle income countries even though the disease burden in these countries is significantly higher [
48]. As a result, many countries such as China, Japan and Korea have developed their own robotic systems with the aim of improving cost-effectiveness. Only one study compared the hospital cost of the MH system to the DV system in sigmoid colectomy which accounted to 23.6% savings on the MH system. Other studies such as Alip et al. [
31] predicted a 42% reduction of cost using the Revo-i robotic system for radical prostatectomy and Wang et al. [
37] predicted a 75% reduction in cost using MH system for simple cholecystectomy. The achieved savings without compromising clinical outcomes are promising but must be interpreted with caution as these figures were not validated externally.
In addition to cost, another barrier to clinical implementation is robotic training. The learning curve for each system will be variable. Most of the procedures in this review were performed by the same group of surgeons on 2 different platforms suggesting the feasibility of skill transfer between robotic platforms. This concept has yet to be proven in clinical studies. A successful crossover of skills across different robotic platforms would open the possibility of health systems acquiring different robotic platforms to suit specific clinical circumstances without the need to retrain their robotic surgeons.
In this study, we focused our systematic review on novel multi-port soft tissue robotic systems with published comparison data to demonstrate the safe implementation and efficacy of these systems. Other emerging multi-port robotic systems with early clinical data did not fit our review criteria but possessed great potential due to their distinct design elements. SSI Mantra™ (Sudhir Srivastava Innovations Pvt. Ltd, Haryana, India) design featured a modular system with cardiac surgery specific instruments. Switzerland designed and manufactured Dexter robotic system (Distalmotion, Epalinges, Switzerland) used a modular platform and instruments compatible with standard laparoscopic ports. This facilitates seamless transition between laparoscopic and robotic approaches and extended the application of robotic surgery into the ‘hybrid realm’. Hinotori™ surgical robot system (Medicaroid Inc., Kobe, Japan) was designed with a compact operation arm that couples eight axes of motion to reduce interference between the robotic arms and bedside surgeon. Avatera robotic system (Avateramedical GmbH, Jena, Germany) featured a thin space-saving patient cart, equipped with disposable 5 mm robotic instruments. This eliminated the need for costly sterilization.
Other robotic systems such as the da Vinci’s single port robotic system which utilized a single surgical entry site and Endoquest robotic system (Endoquest Robotics, Houston, Texas, US) to conduct endoluminal procedures (i.e., submucosal dissection, endoscopic mucosal dissection) were beyond the scope of this review.
The main limitation of this review was the lack of data from RCTs. Most of the studies were retrospective case series. The retrospective nature of the studies would have inevitably introduced selection bias in our analysis with surgeons selecting surgical approaches most suitable for their skillset and robotic platform. The 2 RCTs compared patients with low ASA scores, low comorbidity state, and low BMI which limited the application in the obese and elderly population with higher burden of diseases.
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