One of the distinctive features of the da Vinci X Surgical System from Intuitive Surgical is “the long fourth arm.” The da Vinci X was introduced as a more accessible version of the Xi platform, sharing the same console and vision system while simplifying the architecture of the patient-side cart.
A key element is the original column design of the patient-side cart (which started with the first da Vinci Standard), where the four robotic arms are arranged around the central column on the four sides. This configuration means that one of the arms naturally approaches the operative field from the back of the column (it is the same in the first, second and third generations, da Vinci Standard, S and Si).
To allow this posterior arm to effectively reach the surgical field, the fourth arm incorporates an additional articulation, giving it a longer and more flexible reach compared with the others. This extra joint enables the arm to extend forward from behind the column and still achieve the necessary working angles.
In transoral robotic surgery (TORS), this design can be used to advantage. By placing the patient-side cart parallel to the operating table, rather than directly at the head of the patient (in the original 30º position designed by Greg Weinstein at the very beginning of TORS), the long fourth arm can effectively reach the surgical field (this setup is described in a previous post: setup for TORS with the da Vinci X).
In the video attached to this post, you can see a short walkthrough the range of the fourth arm, illustrating how this additional articulation allows it to reach the operative field from behind the column. Once your are set for TORS with the da Vinci X, you will notice no difference if you are working with de da Vinci X or the da Vinci Xi.
J Granell. Mar 9, 2026