High pressures are generated at the tip of laparoscopic graspers

Background: Despite its importance the interface between tissue and instrument is poorly understood. Methods: A thin film pressure transducer was deployed between the jaws of eight different laparoscopic instruments and a simulated tissue to study the forces generated at the tip of laparoscopic graspers and the effect of a change in angle of tissue tension at the interface between tissue and laparoscopic grasper. Results: Pressure was concentrated at the tip of the instrument. Localized pressures increased on average from 210 kPa to 650 kPa as the angle of grasp was increased from 0 to 135°. There was a wide variation between instruments with some exhibiting increases in tip pressure of a factor of eight as the angle was increased. Conclusion: High pressures are generated at the tip of laparoscopic graspers. Pressures increase as the angle of incidence of the grasper in relation to the tissue increases. The changes in pressure with change in angle are independent of load and handle pressure.