A Sensory Feedback System with Pneumatic Dual-Structure Tactile Display for Softness Assessment during Laparoscopic Surgery

In laparoscopic surgery, the surgeon’s tactile sense is restricted. We aim to enable softness assessment by providing tactile feedback to the surgeon for adenomyosis of the uterus. Tactile feedback is effective for not only accurate softness discrimination but also adequate operation. This paper proposes a sensory feedback system with a pneumatic dual-structure tactile display, which presents information on the pressure distribution obtained by a softness sensing probe. The tactile display has central and peripheral stimulation areas, which expand due to air pressure to present, for the concentration and dispersion of pressure on the finger pad. This display is lightweight, cost-effective, sterilizable, and disposable. It is mounted on a sensing probe handle, which we previously developed and is available for clinical use by the acoustic sensing principle. To emphasize the pressure distribution by the dual structure, a gain adjustment was proposed. Fundamental test on the tactile display and the psychophysical experiment on the feedback system with confidence rating and pressing force measurement were conducted. The discrimination sensitivity and confidence were significantly improved, and the pressing force was significantly reduced using feedback. The results indicated that the proposed system is effective for softness assessment and safe operation during laparoscopic surgery.