Comparison of 8 and 5 mm robotic instruments in small cavities : 5 or 8 mm robotic instruments for small cavities?

Robotic surgery has seen increasing use in the field of pediatric surgery. Our clinical experience suggested instrument size can impact on the surgical ability. This study aimed to compare the performance of robot-assisted laparoscopic skills in confined spaces using either 5 or 8 mm instruments.

A preclinical randomized crossover study design was implemented. 24 assessors performed three different reproducible drill procedures (M1: peg transfer, M2: circle cutting, M3: intracorporeal suturing). To assess surgical proficiency in confined working spaces, these exercises were performed with 5 and 8 mm instruments of the da Vinci^® Surgical Systems Si in a cubic box with 60 mm-sized edges. Each performance was recorded and evaluated by two reviewers using both objective structured assessment of technical skills (OSATS) and global evaluative assessment of robotic skills (GEARS) scores. Parietal iatrogenic impacts and instrument collisions were specifically analyzed using a dedicated scoring system.

Regardless of their experience, trainees performed significantly better when using 8 mm instruments in terms of OSATS scores (20.5 vs. 18.4; p < 0.01) and GEARS scores (23.4 vs. 21.9; p < 0.01) for most items, except for "depth perception" and "autonomy." The 8 mm performances involved significantly less parietal box damage (4.1 vs. 3.4; p < 0.01), and tool collisions (4.1 vs. 3.2; p < 0.01).

In light of the better performances with 8 mm tools for specific tasks and parietal sparing constraints in restricted spaces, this study indicates that 5 mm instruments can be deemed to be less effective for reconstructive procedures in small children.