Development of optical fiber Bragg grating force-reflection sensor system of medical application for safe minimally invasive robotic surgery

Abstract

Force feedback plays a very important role in medical surgery. In minimally invasive surgery (MIS), however, the very long and stiff bars of surgical instruments greatly diminish force feedback for the surgeon. In the case of minimally invasive robotic surgery (MIRS), force feedback is totally eliminated. Previous researchers have reported that the absence of force feedback increased the average force magnitude applied to the tissue by at least 50%, and increased the peak force magnitude by at least a factor of two. Therefore, it is very important to provide force information in MIRS. Recently, many sensors are being developed for MIS and MIRS, but some obstacles to their application in actual medical surgery must be surmounted. The most critical problems are size limit and sterilizability. Optical fiber sensors are among the most suitable sensors for the surgical environment. The optical fiber Bragg grating (FBG) sensor, in particular, offers an important additional advantage over other optical fiber sensors in that it is not influenced by the intensity of the light source. In this paper, we present the initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments and suggest the possibility of successful application to MIRS systems.

A Submillimetric 3-DOF Force Sensing Instrument With Integrated Fiber Bragg Grating for Retinal Microsurgery

“…The force sensor is based on intensity modulated fiber optic sensors and can provide a resolution of 0.04 N. Puangmali et al [7] designed a triaxial distal force sensor for tissue palpation in MIS, also based on intensity modulated fiber optic sensor with 0.02 N resolution. Furthermore, various distal force sensing techniques for MIS applications have been developed based on piezoresistor [8]–[11] and fiber optical sensor [12][13]. Although the aforementioned works show promising results, they are not compatible with the requirements of retinal microsurgery.…”

A novel MRI compatible soft tissue indentor and fibre Bragg grating force sensor

“…This is sufficient for application to (non- Other researchers have developed more complex tri-axial force sensor systems (e.g. [14,31,32,45]) for MRI. However the uniaxial force measurements presented here ensured a simple and compact indentor design and are sufficient for comparison to inverse FEA as the same resultant uniaxial force can easily be generated as an output.…”

“…In this study a FBG sensor system is proposed because these have several advantages over other optical force sensing systems [14]: 1) measurement is independent of fluctuating light levels, 2) multiple gratings can be applied in series and 3) they have simple wiring and a compact implementation. This paper outlines the design of a complete system for soft tissue indentation which is MRI compatible.…”

“…MRI compatible optical force sensors have been proposed for analysis of needle deflection and force feedback measurement during MRI based catheterisation have also been developed [15,30] however these are applied to relatively low forces in the range 0-0.5 N. Tokuno et al [31] However when in a later study [26] the authors used the system for human finger-tip indentation the force, acquired at 1 Hz, was found to vary with a standard deviation of up to 0.3 N around a static mean load of 2.35 N. The causes for these increased deviations, with respect to the calibration, were not discussed. Recently Song et al [14] designed an advanced Fibre Bragg Grating (FBG) based triaxial force sensor mounted on a robot arm. Forces where calibrated up to ~10 N and a maximum force error of 0.5 N was recorded.…”

“…[10,11]), MRI guided surgical interventions (e.g. [12][13][14]), MRI based catheterisation (e.g. [15]), functional MRI (e.g.…”