In our study, we conducted different surgeries on both sides of the same pig. This was done to ensure that the technical difficulty of the operations was comparable between the robotic and endoscopic groups.

The primary outcome was the total operative time, and we found no significant or clinically meaningful difference between the two groups. In fact, the total operative time in the robotic group was only ~6 min longer than that in the endoscopic group. Our results were in line with those reported by Dai et al., who conducted a study involving 12 porcine models to compare KD-SR-01 robotic partial nephrectomy and laparoscopic partial nephrectomy.26 In their study, although the operative time in the robotic group was 11 min longer than that in the laparoscopic group, they also found no significant difference between the two groups. Notably, when we removed the docking time in our study, the time required for surgical procedures was almost identical between the robotic and endoscopic groups. As demonstrated by the above findings, operative times were not necessarily prolonged when using this newly developed surgical robotic platform in porcine models. However, in real-world clinical settings, it remains uncertain whether robotic surgery can match the surgical duration of conventional procedures.27,28,29 Kim et al. posited that extensive training can markedly decrease the duration of robotic surgeries. Their research demonstrated significant reductions in the average operation time associated with robot-assisted neck dissections as experience accumulated.30 One study even revealed that, with extensive training of the robot, surgical duration could be reduced by up to 40%.31

Robotic surgery comes highly recommended not only for its efficiency but, more importantly, for its potential to enhance aesthetic outcomes, improve bleeding control, and minimize complications, among other benefits.32,33 Given the extensive blood flow in the head and neck region, effective bleeding control and maintaining a clear surgical field are crucial for robotic surgery. Lim et al. observed notably lower estimated blood loss using the da Vinci system, especially in complex cases like post-styloid parapharyngeal space tumors.29 Although it has not been used in human head and neck surgery, the KD-SR-01 has achieved bleeding control in colonic surgeries compared to that of the da Vinci robot.25 Our results demonstrated that this system was also well in controlling bleeding in head and neck surgery in the porcine model. This enhancement in blood loss control can be attributed to the sophisticated capabilities of robotic systems, which encompass features such as tremor reduction, 3D imaging, and surgical instruments with a wider range of motion. These attributes collectively empower surgeons to more accurately identify and dissect blood vessels within the correct anatomical planes. However, it is worth noting that in our study, during SMG resection, we observed no statistically significant differences in estimated blood loss between the two groups. This can be attributed to the distinct anatomical characteristics of the porcine SMG, which possesses a well-defined boundary with the surrounding tissue and relatively fewer blood vessels in proximity. Besides bleeding control, the protection of critical nerves is also very important for some head and neck surgeries.7,34,35 IFNM was utilized and the results demonstrated that the facial nerve was protected well during operations.

In this study, all surgical incisions made behind the ear root and mandibular ramus in porcine models were designed to simulate the trans-hairline approach used in human surgery. This specific incision technique was initially proposed by Woo for their endoscope-assisted procedures, demonstrating its feasibility.21 Subsequently, Yang reported on a series of 24 patients who underwent robotic sialoadenectomy using the trans-hairline approach, highlighting its practical application in robotic head and neck surgery.36 Then, Yang et al. conducted studies that demonstrated the surgical configuration and procedures of robotic trans-hairline SMG resection using flexible, single-port, and multi-arm systems.37 Although the trans-hairline incision cannot achieve a completely scarless body surface, it is virtually undetectable when concealed within the hair. Moreover, this type of incision is associated with fewer complications and effectively balances aesthetic and therapeutic outcomes.38 According to our study, we have successfully completed all operations using the simulated trans-hairline approach in porcine models with the KD-SR-01. We intend to continue using this approach in the forthcoming clinical trial, which was registered at www.chictr.org.cn (ChiCTR2300076776).

In terms of cognitive workload, the surgical robot demonstrates significant advantages over standard endoscopic surgery. The robotic systems provide surgeons with a more comfortable operating posture, unlike standard endoscopy, which often requires maintaining awkward and physically demanding positions for extended periods. By allowing surgeons to sit at a console with optimal ergonomic support, robotic systems reduce physical strain and fatigue. Additionally, robotic arms offer a greater range of motion than human hands, and the instruments can articulate far beyond the capabilities of standard endoscopic tools. This enhanced maneuverability allows for more precise dissections, reducing the cognitive workload associated with the fine control of instruments. Furthermore, robotic systems include mechanisms that filter out hand tremors from the surgeon’s movements, enhancing the precision of surgical tasks. This steadiness is particularly valuable during delicate procedures and can significantly reduce the mental effort required to achieve precise movements. For assistants, robotic surgery alleviates the need to hold instruments in a fixed position for long durations, a common requirement in standard endoscopic surgery. As a result, the surgical team can concentrate more on the strategic aspects of the operation rather than the technical challenges, potentially leading to improved decision-making and outcomes.

It is important to note that these experimental findings do not directly establish that the robot can produce similar results in humans, primarily due to the anatomic disparities between humans and pigs. First, while the parotid gland of the pig is larger, it lacks the precise blood vessels and main facial nerve running through it. In humans, the parotid gland contains many blood vessels and features a more intricate facial nerve structure, which heightens the complexity of the surgery. Second, the SMG in pigs features a denser envelope and presents a well-defined boundary with the surrounding blood vessels. Third, the larger lower jaw in pigs, in comparison to that of adult humans, results in a greater distance for the surgical instruments to traverse from behind the pig’s ear to the leading edge of the parotid gland and the lower boundary of the neck. This extended distance also contributes to the heightened surgical complexity. These dissimilarities underscore the necessity of conducting robotic clinical trials to bridge the gap between animal models and human applications.

In the realm of surgical robots, comparisons between the newly developed surgical robotic system and the da Vinci system are inevitable. Regarding postoperative outcomes, Li et al. conducted a comparative study on robot-assisted partial nephrectomy (RAPN), a common and representative procedure, to assess these two systems.39 Their study, comprising 99 RAPN surgeries (49 with KD-SR and 50 with da Vinci), indicated that the KD-SR achieved efficacy comparable to the da Vinci robot, with no significant differences in complication rates between the groups. Additionally, Fan’s study on robot-assisted radical prostatectomy (RARP) using the KD-SR also reported similar short-term oncological and functional outcomes, albeit with a longer operation duration compared to the da Vinci system.40 They suggested that the operational efficiency of the KD-SR might be enhanced through more comprehensive training, as evidenced by their extensive experience gained from over 400 RARP cases with the da Vinci system. In addition to its successful application in urological surgeries, the KD-SR-01 is as effective as the da Vinci system for colon cancer procedures.25 The performance of the KD-SR-01 in these procedures therefore raises expectations for its application in head and neck surgeries.

This study had some limitations that need to be considered. First, the extrapolation of our results from preclinical models to human application may be limited due to inter-species differences.41 As such, the necessity for further clinical trials is evident, and we are actively working to promote such trials to bridge the gap between preclinical and clinical settings. Second, in our effort to assess the potential applicability of the KD-SR-01 in head and neck surgery, we conducted three distinct procedures. This approach, while informative, resulted in relatively small sample sizes for each procedure. Lastly, when evaluating the KD-SR-01, it is worth noting that comparing it with established platforms like the da Vince system may provide a more objective assessment.

This newly developed robotic system has preliminarily demonstrated its technical feasibility, safety, and validity in head and neck surgery. This innovative system offers distinct advantages from an ergonomic perspective, particularly when compared to traditional endoscopic surgery. Despite the promising potential of KD-SR-01, it is imperative to underscore the necessity for a meticulously designed clinical trial, inclusive of an extensive follow-up period. This would be pivotal in rigorously evaluating the true efficacy and utility of the KD-SR-01. Conducting such a comprehensive study is essential to gain a holistic understanding of the system’s strengths and limitations within a clinical setting.