During laparoscopic operations, the trocars are often out of the viewing field of the laparoscope. Blind insertion of laparoscopic instruments is potentially dangerous especially when they are pointed or hot. A guidance of the instrument to the target point has the potential to improve the safety of instrument insertion. In this study, the effect of a mechanical and an optical tool for guided instrument insertion into the abdominal cave was evaluated. The controlled prospective randomized study measured safety and efficiency of instrument insertion by 60 novices in an inanimate standardized box trainer. A post-test questionnaire based on the NASA Task Load Index prompted for the subjective impressions of the subjects. Instrument insertion with optical guidance showed a shorter (p = 0.002) insertion time (median 87.5 s for nine insertions) compared with blind insertion (median 112.0 s for nine insertions). The error number with optical guidance (median 0.5) was lower (p = 0.064) compared with blind insertion (median 1.0). The mechanical guidance showed a shorter (p = 0.001) insertion time (median 89.0 s for nine insertions) and less (p = 0.044) touch errors (median 0) compared with blind insertion. The results of the two guidance tools (mechanical vs. optical guidance) showed no significant difference. In the questionnaire, 89% of the novices subjectively judged the mechanical guidance tool better than blind insertion. The assessments of optical compared to mechanical guidance turned out quite similar. In the experimental setup, instrument insertion with a guidance tool performed faster and safer compared with blind insertion. The subjective assessments confirmed the benefit of instrument guidance.
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