Theoretical background of our original single-incision laparoscopic-assisted surgery technique for colon cancer via a periumbilical approach]

We assessed the theoretical background of our original single-incision laparoscopic-assisted surgery( SILS) technique involving a periumbilical approach. The subjects included 10 cases who underwent periumbilical SILS colectomy and had their surgical wounds photographed before and after skin incision between September 2009 and October 2010. Using an image analyzer, we estimated the theoretical oval area after a 3/4-circumferential periumbilical skin incision, the actual oval area after placement of the wound retractor, and the length of the skin incision. The mean oval area after the placement of the wound retractor was 2.9 times (range: 1.6-5.0 times) larger than that of the theoretical area. The square of the length of the skin incision positively correlated with the actual oval area created by placing the wound retractor( p=0.04, r=0.67). There were 5 patients, whose actual oval area was ≤700 mm2, and thus required additional radial skin incision( s)( 1 in 3 cases, 2 in 1 case and 3 in 1 case). When performing our original SILS via the periumbilical approach, the area of the actual surgical window can be predicted by measuring the distance from the center of the umbilicus to its edge.