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.