Analysis of laparoscopic dissection skill by instrument tip force measurement.

BACKGROUND

When comparing a single-stroke dissection maneuver among surgeons with differing experience levels, there are major differences in the force applied to the instrument tip. It is difficult to explain to surgeons in training the appropriate force and for the surgeons to ascertain the force intuitively. We quantified the force pattern during single-stroke laparoscopic dissection maneuvers to reveal the factors related to expertise.

METHODS

We recorded the force pattern of a single maneuver and measured the magnitude of vertical (VF) and horizontal forces (HF) on the instrument tip using a box trainer (ex vivo). We compared VF and HF among surgeons: experts (n = 10), intermediates (n = 10), and novices (n = 10). The dissection time of a single stroke (T), magnitude of the VF and HF, and the timing of the peak vertical force (TPV) and horizontal force (TPH) were evaluated as performance parameters.

RESULTS

The dissection time of a single stroke (T) was shortest in the expert group (p < 0.05). The average maximum magnitude of VF and HF was smallest in the expert group. TPV occurred significantly earlier than TPH in all three groups (p < 0.05). TPV in the expert group occurred earlier than in the intermediate and novice groups (p < 0.05). With increasing experience, TPV occurred earlier.

CONCLUSIONS

Expert surgeons apply the most efficient vertical forces to make an initial dissection point and then change to the horizontal direction to separate surrounding tissues from the target organ. Measuring instrument tip force could help in understanding and improving the safety margin in laparoscopic surgical dissection.