Robotic versus non-robotic instruments in spatially constrained operating workspaces: a pre-clinical randomized crossover study

Objective: To compare the effectiveness of robotic and non-robotic laparoscopic instruments in spatially constrained workspaces.

Materials and methods: Surgeons performed intracorporeal sutures with various instruments within three different cylindrical workspace sizes. Three pairs of instruments were compared: 3-mm non-robotic mini-laparoscopy instruments; 5-mm robotic instruments; and 8-mm robotic instruments. Workspace diameters were 4, 6 and 8 cm, with volumes of 50, 113 and 201 cm(3) respectively. Primary outcomes were validated objective task performance scores and instrument workspace breach counts.

Results: A total of 23 participants performed 276 suture task repetitions. The overall median task performance scores for the 3-, 5- and 8-mm instruments were 421, 398 and 402, respectively (P = 0.12). Task scores were highest (best) for the 3-mm non-robotic instruments in all workspace sizes. Scores were significantly lower when spatial constraints were imposed, with median task scores for the 4-, 6- and 8-cm diameter workspaces being 388, 415 and 420, respectively (P = 0.026). Significant indirect relationships were seen between boundary breaches and workspace size (P < 0.001). Higher breach counts occurred with the robotic instruments.

Conclusions: Smaller workspaces limit the performance of both robotic and non-robotic instruments. In operating workspaces <200 cm(3) , 3-mm non-robotic instruments are better suited for advanced bimanual operative tasks such as suturing. Future robotic instruments need further optimization if this technology is to be uniquely advantageous for clinical roles that involve endoscopic access to workspace-restricted anatomical areas.