The impact of trocar-cannula design and simulated operative manipulation on incisional characteristics: A randomized trial

To evaluate the hypothesis that abdominal muscular and fascial defects associated with 12-mm blunt conical trocar-cannula system will be similar to those associated with 8-mm pyramidal trocar-cannula system, both with and without simulated operative movements. A randomized trial was performed in an animal (white swine) model. Four trocar-cannula system groups were evaluated: group A, 12-mm blunt conical system, no operative manipulations; group B, 12-mm blunt conical system, standardized operative manipulation; group C, 8-mm pyramidal system, no operative manipulations; group D, 8-mm pyramidal system with standardized operative manipulation. These 4 groups were randomly assigned across 8 animals and 6 locations for a total of 48 insertions. After the cannulas were removed, the skin and subcutaneous tissues were dissected to expose the fascial wounds. Maximal incisional length, wound area, and muscle damage score were determined for each defect. Mean wound area was 8.58 mm(2) in group A, 9.71 mm(2) in group B, 9.83 mm(2) in group C, and 9.63 mm(2) in group D. Incisional length was 9.16 mm in group A, 9.61 mm in group B, 9.14 mm in group C, and 8.52 mm in group D. There were no statistically significant differences between any 2 groups. Mean muscle injury scores were also similar for all groups. Twelve-millimeter conical trocar-cannula systems create fascial defects similar to those of 8-mm pyramidal systems, both immediately after insertion and after simulated operative manipulations. Given the historical low risk of wound dehiscence and hernia associated with pyramidal devices less than 10-mm in outside diameter, fascial closure of wounds created by conical systems may be unnecessary.