Miniature 3-Axis Distal Force Sensor for Minimally Invasive Surgical Palpation

Minimally invasive surgery (MIS) is a surgical technique that offers distinct advantages in reducing pain and patients' recovery time. However, the drawback due to the lack of force and tactile feedback presents a great deal of limitations in MIS procedures. Tissue palpation, which is easily conducted during traditional open surgery to examine tissue properties and abnormalities, is not possible when performing surgery in a minimally invasive manner. This paper proposes a specially designed miniature 3-axis distal force sensor that can be used to perform tissue palpation, measuring tissue interaction forces at the tip of a surgical instrument. Relying on an optical sensing scheme, the sensor can measure forces within measurement ranges of +/- 3 N in axial direction and +/- 1.5 N in radial direction. The resolution is 0.02 N. It is compatible with laparoscopic operations and can be used to localize tissue lesions or relatively hard nodules buried under an organ's surface, which are not detectable by visual means.