It is essential to have indicators, parameters, and metrics that can differentiate between different levels of surgical skill. Laparoscopic surgery is no exception and demands psychomotor dexterity, ambidexterity, hand–eye coordination, adaptation to loss of depth, and, of course, the safe handling of instruments. Laparoscopic surgery is performed using four degrees of freedom. Rotational movements around the axis are essential in laparoscopy, where surgeons must handle instruments with great dexterity to perform procedures in confined spaces and with indirect visualization. Therefore, smooth, controlled, and effective rotations are required.

In the literature, the most evaluated metrics are time, accuracy, errors, and those derived from laparoscopic movement, such as path length and economy of movement. Although metrics derived from motion analysis have proven to be useful for the evaluation of surgical skills, most simulators only analyze linear motion, which represents 3 of the 4 DoF present in laparoscopic settings (movement along the x-axis, y-axis, and z-axis, respectively) and left out the 4th DoF (rotation around the z-axis).

New laparoscopic techniques require complex skills as do new surgical instruments. Addressing the limitations of traditional simulators, such as the lack of feedback on rotational movements, limits the ability to provide objective feedback on movement control in 3D space, which is crucial for improving laparoscopic psychomotor skills. The ability to record instrument rotation in laparoscopic procedures is crucial for understanding and improving dexterity in this minimally invasive surgical technique. Recording these movements can provide several valuable insights into laparoscopic skill training as it allows us to gain a comprehensive understanding of the surgeon's motion performance. The ScopePro system was developed to address the lack of angular motion analysis in low-cost Box trainer systems. In general terms, ScopePro can record instrument rotation around the z-axis in laparoscopic procedures, representing a significant advance in surgical skills training.

Recording rotation around the instrument's axis could help surgeons develop complex motor skills. This capability would enable more realistic surgical scenarios that require precise movements in various planes, angles, and directions. By incorporating rotation recording into simulators, training becomes more aligned with the psychomotor development of minimally invasive psychomotor skills. This improvement could enhance the transfer of skills from training to the operating room as it would provide objective feedback on how precision in movements impacts surgery. The ScopePro system would contribute to more effective training, providing objective and personalized feedback that could improve surgeons’ competency in the surgical setting.

Overall, motion metrics (Path length, Clockwise turns, Counterclockwise turns, and Total turns) along with the time metric showed a tendency to decrease their magnitude as the experience level increased. The Ratio metric indicates the correlation between the number of turns and the instrument path, which can be interpreted as the economy of turns. This analysis showed more economy of turns in the dominant hand. The tendency for the ratio metric was to increase as the skill level increased; this is due to the path length in the denominator of the ratio decreasing faster than the total turns in the numerator. Regarding the differences in the ratio for dominant and non-dominant hands, a learning process could explain which mastery of the right dominant hand is first achieved in most cases. Then, as experience increases, the ambidexterity characteristic of experts is acquired. However, future studies will be carried out to test this hypothesis.

The study indicates that different hand movement metrics, such as the number of turns and Ratio, vary across levels of laparoscopic experience, with dominant hand movements improving first and non-dominant hand movements showing more improvement with increased experience. These findings suggest a learning process in which expertise is characterized by greater efficiency and coordination, potentially leading to ambidextrous behavior in experts. Future research is needed to explore this hypothesis further. Notably, both the number of turns and the ratio metrics were able to distinguish between different skill levels in some instances, where the traditional path length associated with linear motion could not.

A recent study conducted by Heiliger et al. [8] provides strong support for the implementation of simulation techniques to enhance learning using an inertial navigation system, which combines multiple sensors. Three parameters stood out, showing performance improvement. One of these parameters, highlighted, was the number of rotations of the instrument around its axis. The ScopePro Trainer could be integrated into surgical training programs through a combination of complementary methods. Its inclusion will depend on the structure of the curriculum, but it could be useful in the initial stages of training, focusing on basic technical skills training. It could also serve as a complementary tool in simulators to improve proficiency in endoscopic procedures without replacing clinical practice. The cost of the ScopePro Trainer may vary depending on factors, such as model, associated services, and scale of implementation.

For this functional prototype, the cost was approximately 500 USD. This cost per unit could be reduced when produced in higher quantities, making this device a low-cost option for institutions in need of Box trainers with surgical skills evaluation capabilities. Additionally, the portability of the ScopePro system, along with its relatively low cost, means that individuals interested in practicing their skills at home could benefit from this system.

Although the ScopePro Trainer system has demonstrated its ability to differentiate between participants with varying skill levels, further studies are necessary to thoroughly explore its capabilities. First, studies with more expert participants are needed. Although a post hoc power analysis indicates that most metrics have above 80% statistical power, having only four expert surgeons is insufficient to build a sufficiently robust database for automatic, objective evaluation by comparing a new user with known surgeons. Future studies with more extensive teams from other centers and laparoscopic surgeons from other specialties are needed to validate the reliability of the system and enforce its role. Furthermore, future studies are necessary to determine whether these new video-based metrics apply to other tasks. There are other aspects of the validation pending, such as face and content validity. Future studies will revolve around using the Messick validity framework to improve confidence in the ScopePro system. Once the system validation has been expanded, it will be tested in longitudinal studies to research the impact of the system on improving the learning curve of aspiring surgeons, as well as to quantify whether the use of the ScopePro system results in fewer operative errors. These studies will help determine if the acquired skills are transferable to the operating room.

The ScopePro Trainer system, based on computer vision techniques, offers a non-invasive solution for tracking and analyzing the rotational movements of laparoscopic instruments along their axis without altering the surgeons' natural performance. Due to the portability offered by the system, the ScopePro Trainer system can be included in surgical training programs to teach future surgeons.