Purpose: Noninvasiveness and stability are significant issues in laparoscopic liver resection. Inappropriate grasping force can cause damage or serious bleeding to the liver. In addition, instability of grasping can result unsafe operations or wavered cutting. We propose a surgical device to improve stability of liver manipulation.
Methods: A proposed device adheres to the liver surface with suction fixation, then tunes its stiffness to being hard and shapes like as a bulge on the liver surface to be grasped with laparoscopic forceps. It consists of two soft beams, a chamber sponge, membrane covering the device upper, suburb extrusion wing membrane, a vacuuming tube and to-be-grasped bars. The beams are designed as being non-stretchable and easy to bend. The device is connected to a medical vacuuming pump to vacuum air in the device and then gets hard to transfer forceps operation well. This stiffness tuning mechanism by pneumatic control features the device for achieving good liver shape followability and forceps operation propagation less invasively. The proposed device was tested with rubber phantoms and porcine livers on shape followability, stiffness transition, liver invasiveness and operational usability in the experiments.
Results: Performance of the proposed device was assessed in experiments. The device showed good object-shape followability. It held the liver with 2.43-N force for vertical lifting and 4.90-N shear force with - 80 kPa vacuuming pressure. Invasiveness was reduced to acceptable level of liver damage. In usability test, the device grasped the liver stably and transferred surgical forceps operations to the liver surface well.
Conclusion: The proposed device showed effective performance to improve laparoscopic liver manipulation. It held the liver stably and less invasively and transferred forceps operation force to the liver surface well.
Keywords: Laparoscopic surgery; Liver manipulation; Stiffness tuning; Suction fixation; Surgical device.