Flexible instrument with contact-aided structure and force feedback for endoscopic surgery.

BACKGROUND: Robot-assisted surgery can effectively reduce the difficulty and improve the success rate of the surgeries. However, currently available flexible instruments have several limitations, such as large size, few degrees of freedom, and lack of contact force perception. METHODS: This study proposes a master-slave flexible instrument capable of force feedback. The instrument has a maximum outer diameter of 3 mm and an overall length of 1200 mm. With the internal working channel unoccupied, a three-dimensional force sensing unit is designed based on the neural network. The corresponding master-slave control method with proportional force feedback was also designed to effectively control the instrument. RESULTS: To verify the effectiveness of the system, in vitro and in vivo experiments were conducted. The corresponding tasks were successfully completed. CONCLUSIONS: The animal trial conducted in the digestive tract of a live swine proved that the system has the potential for clinical use.

Miniature Flexible Instrument with Fibre Bragg Grating-Based Triaxial Force Sensing for Intraoperative Gastric Endomicroscopy.

Optical biopsy methods, such as probe-based endomicroscopy, can be used to identify early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicking during endoscopy. In this work, we propose a miniaturised flexible instrument based on contact-aided compliant mechanisms and fibre Bragg grating (FBG) sensing for intraoperative gastric endomicroscopy. The instrument has a compact design with an outer diameter of 2.7 mm, incorporating a central channel with a diameter of 1.9 mm for the endomicroscopic probe to pass through. Experimental results show that the instrument can achieve raster trajectory scanning over a large tissue surface with a positioning accuracy of 0.5 mm. The tip force sensor provides a 4.6 mN resolution for the axial force and 2.8 mN for transverse forces. Validation with random samples shows that the force sensor can provide consistent and accurate three-axis force detection. Endomicroscopic imaging experiments were conducted, and the flexible instrument performed no gap scanning (mosaicking area more than 3 mm2) and contact force monitoring during scanning, demonstrating the potential of the system in clinical applications.

Robust Mosaicing of Endomicroscopic Videos via Context-Weighted Correlation Ratio.

Probe-based confocal laser endomicroscopy (pCLE) is a promising imaging tool that provides in situ and in vivo optical imaging to perform real-time pathological assessments. However, due to limited field of view, it is difficult for clinicians to get a full understanding of the scanned tissues. In this paper, we develop a novel mosaicing framework to assemble all frame sequences into a full view image. First, a hybrid rigid registration that combines feature matching and template matching is presented to achieve a global alignment of all frames. Then, the parametric free-form deformation (FFD) model with a multiresolution architecture is implemented to accommodate non-rigid tissue distortions. More importantly, we devise a robust similarity metric called context-weighted correlation ratio (CWCR) to promote registration accuracy, where spatial and geometric contexts are incorporated into the estimation of functional intensity dependence. Experiments on both robotic setup and manual manipulation have demonstrated that the proposed scheme significantly precedes some state-of-the-art mosaicing schemes in the presence of intensity fluctuations, insufficient overlap and tissue distortions. Moreover, the comparisons of the proposed CWCR metric and two other metrics have validated the effectiveness of the context-weighted strategy in quantifying the differences between two frames. Benefiting from more rational and delicate mosaics, the proposed scheme is more suitable to instruct diagnosis and treatment during optical biopsies.

Modular Robotic Scanning Device for Real-Time Gastric Endomicroscopy.

Optical biopsy methods, such as probe-based endomicroscopy, can be used for the identification of early mucosal dysplasia in various gastrointestinal conditions and have potential applications in the screening of early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicing during standard endoscopy. This paper proposes a novel 'snap-on' robotic scanning device that can integrate distally with a commercial endoscope. A customized low-cost endomicroscopy system is used for obtaining micro imaging. The developed device could scan a large area of gastric tissue during standard endoscopy. The device achieves positioning accuracy that is less than 0.23 mm. Experimental results showed that the device could achieve large area mosaicing (15.8-18.6 mm2) and demonstrated the potential clinical value of the device for real-time gastric tissue identification and margin assessment. This approach presents an important alternative to current histology techniques for gastrointestinal tract diagnosis.