As the technology of medical devices has evolved, surgical methods for thyroid surgery have developed tremendously [4]. Since 2007, when robotic systems began their involvement in thyroid surgery, many studies have proven the safety of robotic surgery [8, 12, 13]. Recently, the advantages of robotic surgery have been at the forefront of discussion in the field of surgery, and the most prominent part has been the shortening of operation times [14, 15]. The delicate and steady movements of the robotic arm also make this minimally invasive surgery safe[16]. After the introduction of the da Vinci S followed by the da Vinci Xi, many institutions updated their robotic surgical system from the da Vinci S to the da Vinci Xi, including our institution.
There are several advantages of the da Vinci Xi over the da Vinci S system. The first is the reduction in docking time. In our institution, moving the patient cart of the robotic system during surgery is one of the most difficult surgical steps because the operating room that is assigned for robotic systems is small and rectangular. In addition, since there is only one operating room for robotic surgery, it is necessary to move the patient cart several times to perform several operations in one day. The da Vinci Xi system overcame these difficulties with its slimmer body and arms and the innovative progression, the rotatable boom [17]. The slimmer body allowed the patient cart of the robotic system to be more easily imported and mobile. The restriction of movement was redeemed with the rotatable boom. During thyroid lobectomy with transaxillary incision, one camera port and three acting ports are needed to be inserted through a narrow space. With the S system, the arms are thick and commonly collide with one another. The da Vinci Xi system overcame these difficulties with its narrower arms with greater reach and slimmer endoscopes that can move between ports. This allowed for increased range of motion of the robotic arms. Therefore, these advantages made robot docking easier and faster.
The second advantage is the reduction in console time. Comparing the overall operative time, the Xi group had a significantly shorter operative time than the S group (153.0 min vs. 105.7 min, p < 0.01, Table 3). We divided the operation procedure into individual steps and analyzed each step of the procedures (Tables 1 and 3). From the first step of the operation to the end of the dissection of the superior pole of the thyroid, there was no significant difference between groups in terms of operating time. However, after robot docking, all steps of the procedure, including robot docking, required a shorter time in the Xi group. This is probably due to its versatility resulting from the narrower, longer arms and rotatable boom. The improved resolution from the standard definition vision of the S system to the magnified 3D high definition vision of the Xi system also attributed to making the surgery faster and safer [18, 19]. This allowed surgeons to see the surgical site with true depth perception and crystal-clear vision. With this improved vision, we could find RLNs and PTGs more easily.
For the duration of robot docking and console time, the actual surgical time using the robotic system was significantly reduced after the introduction of the da Vinci Xi system, while the SD also decreased. This reduction in average and SD indicated that steadier and more stable and rapid operations are possible with the da Vinci Xi system. As the SD of the operating time decreased, we were able to more confidently explain the expected operating time to patients. Schedule management for robotic surgery and the surgery itself have also become more predictable.
There were no significant differences in postoperative outcomes and complications between the two groups. After undocking the robot, we performed the same procedures for bleeding control, drain application, and skin closure. The wound closure time was significantly shorter in the Xi group, but it was due to the absorbable subcuticular skin staplers that were only used in this group.
There are a few limitations in this study. First, it is a retrospective, single institution study. In the video file analysis, there may be a few seconds of bias when retrospectively selecting the start and end points of the procedure. Second, the number of patients included is relatively small. However, we were able to see obvious differences between the two groups with a small number. Further studies with larger sample sizes may lead to more definitive conclusions. Third, all the surgeries were performed by a single surgeon, so the learning curve could act as a confounder. Figure 1 shows a steep decline rather than gradual decrease after the introduction of the Xi system. Therefore, it can be concluded that this is due to the convenience of the robot, not the experience of the surgeon.