Evaluation of new motorized articulating laparoscopic instruments by laparoscopic novices using a standardized laparoscopic skills curriculum

Participants in both groups were predominantly male, right-handed and between 20 and 25 years old. Most participants were either in their preclinical or clinical years. Detailed group characteristics can be found in Table 1. Statistical analysis revealed no significant differences between both groups.

Over the last decades mechanical and motorized ALI have been developed to help the surgeon overcome the known obstacles of laparoscopy and, thus, making more difficult procedures possible in a minimally invasive manner. But since their introduction few studies have compared motorized ALI to CLI and their benefit is still unclear [7, 9‐11, 14‐16]. Some studies only compared tasks performed with motorized needle holders, like Robot DEX™ (Déxtérité Surgical, Annecy, France) or Jaimy® (Endocontrol Company, Grenoble, France) [11, 15, 16], whereas others also used several instruments of the Kymerax™ system (Terumo, Tokyo, Japan) comparable to our study [9, 10, 14, 17]. In this trial, we evaluated the performance of new motorized ALI of Karl Storz (KARL STORZ SE & Co., KG, Tuttlingen, Germany), consisting of bipolar scissors, bipolar forceps, and needle holder, in comparison to CLI. All of the above mentioned Kymerax™ studies investigated ALI’s performance in different levels of proficiency (novice, intermediate, expert) and participants per group reached up to a maximum of 25 [9, 10, 14, 17]. In contrast, we wanted to assess the new motorized ALI in a larger cohort of laparoscopic novices to create a homogenous and objective study population and, thus, no potential bias towards CLI as shown in other studies [9, 15].

Our results show that using CLI in the E-BLUS examination was significantly faster and associated with fewer exercise failures than the new motorized ALI. One explanation could be that participants felt overwhelmed by ALI’s additional degrees of freedom and instrument handling combined with the well-known intricacies of laparoscopic surgery. This is further supported by the fact that ALI showed a worse performance in more challenging tasks like NG or LS, as they require a greater depth perception and more complex instrument maneuvers.

These findings are in concordance with above mentioned research of Sieber et al. who found that participants were slower and needed more training time when using Kymerax™ compared to CLI. Their tasks were also performed in a box trainer and comparable to the ones in our study. In contrast to our results, an improved accuracy with ALI use for all exercises was recorded [10]. Our results showed a similar error rate for ALI and CLI in all tasks. It must be noted however, that Sieber et al. used a “fraying factor” for assessing instrument accuracy in cutting tasks, whereas fraying in the cutting task in our trial was not assessed as strictly leading to limited transferability of results [10].

Regarding the skills assessment in our study, it must be mentioned that only time, errors, and exercise failure were observed as foreseen in the original E-BLUS examination. However, this may have confounded our study as we were probably not able to observe the full potential of the new ALI. Especially, when evaluating more complex instruments such as motorized ALI, it would make sense to integrate tissue damage parameters such as instrument movement and interaction force into the skill assessment [18]. In a recent study about force-based laparoscopic skills training, the authors state that it is advisable to first train surgeons on efficient tissue manipulation and instrument handling before allowing them to focus on efficiency of time [19]. In this way, when training with ALI, safe tissue handling, and instrument accuracy could be evaluated more precisely.

Although there are a lot of laparoscopic tasks, we chose to use the E-BLUS examination as a validated basic laparoscopic skills curriculum in our study for reproducibility and transferability of tasks. Additionally, the tasks were selected based on the possibility to complete them with both types of instruments (ALI and CLI). Further, our study cohort only consisted of laparoscopic novices. Since E-BLUS tasks are designed to teach basic laparoscopic skills to young urology residents worldwide, they could therefore easily be transferred to our participants [13]. Furthermore, the E-BLUS examination had already been used with other ALI and showed promising results in beginners [14]. However, using only four basic laparoscopic tasks could be a limitation of our study since the E-BLUS examination was especially designed for the ergonomics of CLI and not for ALI [13]. Most advantages of motorized ALI are seen in more challenging tasks like suturing in difficult angles as seen in performing urethrovesical anastomosis or suturing on organic tissue, i.e. during bowel surgery or partial nephrectomies. Therefore, it would be interesting to explore whether the functionality of the new motorized ALI could be more accurately assessed by more demanding exercises like a “3D pick-and-place task” or ex vivo animal models in further studies [8, 11, 17, 20]. We chose laparoscopic beginners for our study cohort to ensure that we would obtain a large and consistent study population. However, some studies suggest that most advantages of ALI are only seen in experienced laparoscopist [10, 14, 21]. Therefore, it would also be of great interest to see if more experienced surgeons could expand their surgical skills by using the new ALI of our study.

Instrument usability could have played another role in differences of exercise performance in our trial. Participants generally preferred CLI over motorized ALI due to their lighter weight and easier handling. However, the ALI scissors showed promise for circular cutting tasks, as a speed improvement could be noticed in all groups and 88% of participants agreed that the biggest advantage of ALI over CLI could be seen within this exercise. A promising clinical application of ALI could therefore lie within circular cutting tasks, like partial nephrectomies, as already shown by laparoendoscopic single-site surgery using Kymerax™ instruments in a porcine model [17].

In contrast, many participants criticized the ALI needle holder for its opening/closing mechanism and uncomfortable grip. Since the ALI needle holder was used in the NG and LS task, the worse performance of ALI in those exercises could be explained. Although, participants performed LS clearly slower with ALI in our study, surprisingly 61% still believed that the additional degrees of freedom allowed easier knot tying and suturing compared to CLI. Therefore, a potential future application of ALI would be for training purposes of laparoscopic novices if instrument features could be improved further. This is supported by Zapardiel et al. who tested Kymerax™ instruments in physicians with different laparoscopic experience. He found that using ALI could help beginners in training because they needed less time for needle loading and placing a stitch with ALI compared to CLI. However, this advantage could not be seen in physicians with laparoscopic experience as they are already used to CLI [9]. In concordance, another study found that novices outscored experts in terms of net improvement in performance with articulating instruments. To speed the learning process, the authors suggest the use of articulating instruments at an early stage of surgical training [21]. Thus, follows that ALI seem to have their own learning curve and require skills distinct form conventional laparoscopy or open surgery. However, one should keep in mind that ALI are not designed to be a replacement of CLI, but should rather be seen as an add-on to refine laparoscopic capabilities [7]. Therefore, laparoscopic training with CLI and ALI should ideally be combined in a new multi-modality training curriculum to ensure an optimal training benefit with both types of instruments. One approach could be comparable to the multi-modality training for laparoscopic cholecystectomy which has already been explored by Kowaleski and colleagues [22].

In conclusion, using new motorized ALI in a basic laparoscopic skills curriculum by beginners was associated with a slower performance and more exercise failures compared to CLI. One explanation could be that laparoscopic novices felt overwhelmed by the additional features of motorized ALI and ALI have a distinct learning curve that needs to be addressed. However, participants believed that additional degrees of freedom allowed easier knot-tying, suturing, and cutting compared to CLI. Therefore, ALI should be used for laparoscopic training purposes, ideally combined with conventional laparoscopic training in a new curriculum. Enhancing ergonomics and reducing weight could help to further improve ALI’s user-friendliness.