A Microrobot With an Attached Microforce Sensor for Transurethral Access to the Bladder Interior Wall

Abstract

We present the conceptual design and limited functionality prototype and characterization of a system for application in transurethral palpation of any targeted area of the bladder interior wall tissue consisting of a robotic manipulator and a micro-force sensor attached at its tip all less than 3.5mm in diameter. A hyper-redundant 10-joint 6-DOF manipulator (5-DOF rigid and 5-joint continuum segments) is presented along with the forward and inverse kinematics analyses based on a Jacobian formulation to prevent configuration singularities. Simulated motion studies demonstrate the ability of the proposed manipulator to attain a desired pose (normal to the tissue) with any area in the bladder including the difficult to reach trigone area. A strain gauge-based micro-force sensor is designed using finite element analysis (safety factor >3), prototyped using additive manufacturing, and characterized. The characterized sensor was used to acquire in vivo measurements to evaluate human palm tissue viscoelastic properties. A single module of the continuum segment is designed and prototyped using additive manufacturing, and used to characterize its tension-bend angle behavior. Finite element analysis is used to improve structurally weak regions of the vertebra. A 3-joint 4-vertebrae prototype was successfully actuated to reach a bend state using tendons. The developed robot and sensor prototypes demonstrate capabilities of the proposed concept which could be a possible solution to quantitatively evaluate localized biomechanical properties of the bladder tissue to improve treatment and provide better patient care.

Medical 3D Printing Using Desktop Inverted Vat Photopolymerization: Background, Clinical Applications, and Challenges

“…The use of 3D printing technology can enable rapid customization of drill guides for individual patients and has been shown to improve accuracy and reduce the risk of mispositioning during surgery [77]. A miniature force sensor using desktop inverted VP 3D printing was developed which can be inserted into living tissue without causing significant damage, unlike current methods for measuring forces in living tissue that are often invasive and can cause tissue damage [109][110][111]. The authors also noted that the use of 3D printing technology can enable rapid and low-cost production of the force sensor, which could make it more accessible for researchers and clinicians.…”