Analysis of the knot-tying force in dog models

From our experience of endoscopic surgery using the surgical robot da Vinci at our hospital, it has become dear that the lack of a sense of touch of the forceps makes meticulous operations difficult For the development of a surgical robot that would impart a sense of touch, we investigated the appropriate knot-tying force by determining the relation between this force and wound healing in dog models. We cut and then sutured the jejnum of Beagle dogs, using a series of knot-tying forces (03-5.0 N). The jejunum was then removed on the 4 ^th,7 ^th,11 ^th and 14 ^th postoperative days, and the microvessd density for each force was measured to determine the appropriate knot-tying force for the jejunum. The microvessd density in the submucosa on the 7 ^th and 11 ^th postoperative days was significantly higher for theknot-tying force of 1.5 N than for other forces used. Thus, the results of our study suggested that a knot-tying force of 1.5 N was the most appropriate force for suturing of wounds of the jejnum. We consider that this result would be useful for the development of a surgical robot that imparts a sense of touch to the surgeon's hand.