Fenestrations in the jaws of laparoscopic graspers.

Laparoscopic graspers used for manipulating delicate tissue generally possess jaws with fenestrations (windows). The fenestrations should enhance the grip on the tissue; however, fenestrations reduce the contact area between jaws and tissue, leading to higher local pressures and possibly tissue damage. Experiments were performed to determine the effect of a fenestration on the pinch force needed to prevent slip of tissue and on the pinch force leading to tissue damage. In addition, the size and position of the fenestration were determined. Fenestrated jaws resulted in increased tissue damage, without affecting the pinch force needed to prevent slip. These negative effects increased with increasing fenestration size and when the fenestration was located toward the tip of the jaws. Therefore, fenestrated jaws had a smaller safe working range than the jaws without fenestrations.