Randomized comparison of the effect of manipulation on incisional parameters associated with a pyramidal laparoscopic...

We conducted a randomized, controlled trial to evaluate the effect of laparoscopic access cannula manipulation on fascial and incisional characteristics in a white swine model, comparing a pyramidal trocar-cannula system (PTC) and a trocarless threaded cannula (TTC, EndoTIP). We made 6 insertions in 10 animals. Cannulas randomized to the movement group were manipulated in standard fashion in skin and subcutaneous tissues. After dissection, muscle damage scores, wound areas, and maximum wound lengths were determined. Mean muscle damage scores without and with manipulation for the TTC were 0.7 and 1.00, respectively, and for the PTC 1.9 and 2.0. Differences between devices were significant (p = 0.0001) but there were no differences within devices (manipulation vs no manipulation). Mean wound length for the TTC without manipulation (0.699 cm) was less than that after manipulation (1.101 cm, p = 0.0002). The mean nonmanipulated PTC wound length (0.968 cm) was more than that of corresponding TTC wounds (0.699 cm, p = 0.0082) but this difference was lost after manipulation (TTC 1.101, PTC 0.930). Mean wound area for the nonmanipulated TTC was less than that for corresponding PTC wounds (16.99 vs 30.85 mm(2), p = 0.0066) but this difference was lost after manipulation (TTC 24.31 mm(2), PTC 25.97 mm(2)). Thus cannula manipulation had no effect on wound area and an adverse effect on maximum wound length for the threaded cannula only. Despite movement, the muscle damage score remained significantly less for the threaded cannula.