This is the first study to objectively evaluate suturing and its accuracy in small cavities designed for pediatric and neonatal applications using the hinotori™ system. Our results demonstrate that the hinotori™ system could complete each task while ensuring the accuracy of suturing within an operative cavity as small as 125 mL, with no external collisions. Although a number of alerts were initially classified as external collisions, no direct interference was observed owing to the effective control mechanism of the hinotori™ system.
A notable finding of this study was the increase in knot tying times as the cavity size decreased to 256 mL or smaller, suggesting that spatial constraints significantly affect surgical dynamics. Despite the uniform box sizes, the DT showed a higher incidence of collisions than the ET did, indicating that complexity escalates in constrained environments. This is in line with previous findings, which suggest that tighter spaces augment the likelihood of procedural collisions [16–18]. Addressing these spatial challenges in future iterations of robotic systems could enhance the efficiency and safety of the procedure.
Interestingly, the needle handling times remained consistent across all box sizes, underscoring the robust performance of the system even under varying spatial conditions. This consistency is crucial for operations, such as tissue dissection, which require precise manipulation. The performance of the hinotori™ system suggests that it could provide significant advantages over traditional laparoscopic or open surgical approaches, especially in the confined spaces that are typical of pediatric surgeries.
Although previous studies have shown that robotic systems can operate effectively in confined spaces as small as 90–125 mL, our findings extend this knowledge by demonstrating efficient suturing in a 125 mL space using more complex tasks [16–19]. We also introduced nuanced assessments of suturing precision, which are critical for evaluating the capabilities of surgical robots in real-world scenarios. Despite not testing the smallest reported volume of 90 mL, the performance of the system with more demanding tasks suggests that it is on par with or superior to existing technologies.
One of the hinotori™ system’s distinguishing features is its ability to operate without fixed docking, a capability shared by systems like Versius® and Senhance™. This allows for a minimal setup with port distances as short as 2 cm, which may enable “port-free” operations.
A key attribute of the hinotori™ system is its alert function, which is designed to halt operations to prevent contact between external instruments until corrective maneuvers are executed. This feature potentially increases the procedure time but contributes significantly to the safety of surgical operations, making it particularly valuable in neonatal surgeries where precision and caution are paramount.
Our study results indicate that the smallest (125 mL) box yielded the highest suturing accuracy scores, highlighting the system’s capability to maintain precision even in significantly constrained spaces. This finding is notable, especially considering that increased suturing times were observed, likely because of the frequent activation of the alert function and the resulting instrument collisions.
Moreover, the advantages of robotic surgery, such as enhanced visual recognition and magnification, play a crucial role in enabling precise suturing within small operational volumes. These technological benefits are critical, particularly when the surgical targets are consistent, supporting high precision in environments where traditional approaches may be challenging or infeasible.
The alert function of the hinotori™ system significantly enhances surgical safety, which is particularly crucial in neonatal surgeries where precision is paramount. This feature, which is designed to halt operations and prevent contact with external instruments, supports surgical adjustments to prevent unintended contact. Although beneficial, this mechanism may extend the procedure times due to its sensitivity, which prompts frequent halts, especially when operating within the tightly constrained 125-mL space where the system demonstrated its highest suturing accuracy.
This study highlights that despite the limited operational space, the hinotori™ system maintained excellent precision, demonstrating its capability to effectively manage surgical challenges associated with small cavities. The negligible learning curve associated with this system underscores its user-friendliness and efficiency, allowing surgeons to perform delicate tasks with enhanced visual recognition and magnification. These technological advantages are particularly beneficial in neonatal surgeries, where precision is critical and the surgical area is inherently small.
Overall, the findings illustrate that the hinotori™ system, while possibly slowing down procedures due to its alert function, offers significant advantages in terms of safety and accuracy in pediatric surgeries. The ability to perform accurately in restricted spaces without compromising safety demonstrates its potential as a valuable tool in complex surgical settings.
In pediatric robotic surgery, Meehan et al. reported that surgeries on children weighing less than 5 kg can generally be performed without significant issues, though the challenges increase markedly in cases involving children weighing less than 3 kg [25, 26]. Chapman et al. estimated that the volume of the right lung ranges from 92 to 140 mL in infants weighing 5 kg and from 55 to 84 mL in those weighing 3 kg [27]. Regarding the volume of the abdominal cavity, if we assume that the abdominal cavity of a neonate undergoing pneumoperitoneum for laparoscopy is spherical, the estimated volume for a neonate weighing 3 kg is approximately 125 mL [20]. These findings suggest that performing thoracoscopic surgery with the hinotori™ system might be particularly challenging in infants and neonates under 3 kg. In contrast, abdominal procedures might be more feasible at a younger age than are thoracoscopic surgeries, owing to the softer abdominal walls of children compared with those of adults, and the increased volume of the abdominal cavity owing to the pneumoperitoneum. This distinction is crucial in planning and executing surgical interventions using robotic systems in young patients.
Limitations
Despite providing valuable insights, this study has some limitations. First, the generalizability of the results is constrained by the small sample size involving only two highly skilled operators, which may not accurately reflect the learning curve for less experienced surgeons. Additionally, the simulation of pediatric surgical environments using custom-made cardboard boxes fails to replicate the complex and variable anatomy of real pediatric intracorporeal spaces, particularly the soft and elastic properties of neonatal abdominal walls. Furthermore, the experimental setup did not mimic the dynamic operating conditions typically encountered during surgery, such as variations in lighting or patient movement, which could affect the surgical outcomes. Importantly, we did not include a comparative analysis with other robotic systems such as Versius® and Senhance™, which is a critical aspect that should be addressed in future studies.
Given the limitations identified in this study, future research should aim to enhance the realism of surgical simulations using anatomically accurate 3D-printed models that closely mimic the physical properties of pediatric and neonatal tissues. Expanding the participant pool to include surgeons with varying levels of experience will provide a more comprehensive understanding of the learning curve associated with the hinotori™ system. Additionally, it would be beneficial to replicate these experiments in a more dynamic surgical environment to evaluate the system’s performance under typical operating room conditions, including factors such as lighting variations and patient movement. Moreover, future studies should include comparative analyses with other robotic surgical systems, such as Versius® and Senhance™, to better assess the relative advantages and limitations of the hinotori™ system. These studies would not only validate the findings of the current research but may also broaden the applicability of the hinotori™ system in pediatric surgery, ensuring its effectiveness and safety in real-world clinical settings.