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Objective: This paper aims to investigate a new continuum robot design and its motion implementation methods appropriate for a minimally invasive intracerebral hemorrhage (ICH) evacuation. Methods: We propose a continuum robotic cannula, consisting of a precurved body and a 2-degree-of-freedom (DoF) flexible tip, monolithically fabricated. Kinematic model with cable elongation model, and a dedicated design optimization and motion planning algorithm were developed to enable the follow-the-leader (FTL) motion of the cannula. A task-dependent Jacobian-based closed loop control was also designed to track the cannula motion during the insertion and its independent tip motion. Results: Comprehensive experiments were conducted to verify the kinematic model and submillimeter motion coupling between the cannula precurved body and its flexible tip. The cannula was also capable of achieving FTL motion within around 2.5 mm shape deviation and control performance within submillimeter errors. It was finally demonstrated to be capable of the nonlinear insertion and tip manipulation in the brain phantom. Conclusion: The new cannula design, together with the proposed algorithms, provides the unique ability to access ICH in a nonlinear trajectory and dexterous tip motion. Significance: These motion capabilities of the robot in such a slender form factor will lead to more complete ICH evacuation and reduced trauma to the healthy brain tissues. [ABSTRACT FROM AUTHOR]

Flexible endoscopes have been widely adopted in clinical practices, which enable surgeons to observe the inside of the body through natural orifices. However, observing lesions inside the narrow space of the human sinus with existing flexible endoscopes is still challenging due to their large occupied motion space and limited dexterity. In this article, we propose a dexterous hybrid-structure hand-held robotic endoscope (HHRE) for sinus inspection, which composes of a two degrees-of-freedom (DOFs) proximal flexible section and a two-DOF distal articulated wrist structure. Compared with conventional hand-held flexible sinus endoscopes, the proposed HHRE has a larger visual coverage inside the maxillary sinus and smaller occupied motion space due to the two-DOF wrist structure. Our specially designed flexible section and distal articulated wrist structure offer enhanced torsional stiffness to minimize unpredictable view rotations during the diagnostic inspection. The HHRE can be used as a standalone hand-held device or installed on a robotic platform with gravitational force compensation to minimize surgeon's fatigue and improve the usability of the endoscope. Various benchtop experiments and a user study have been performed to validate the effectiveness, reachability, and visual coverage of the HHRE in the maxillary sinus. The user study results show that the proposed platform can potentially improve the usability of the endoscope and reduce surgeons’ workload in performing inspections of the maxillary sinus. [ABSTRACT FROM AUTHOR]

This paper presents the use of shape memory alloy (SMA) spring actuators with real-time cooling to control the motion of the minimally invasive neurosurgical intracranial robot (MINIR-II). A new actuation mechanism involving the passage of water as the cooling medium and air as the medium to drive out the water has been developed to facilitate real-time control of the springs. Control parameters, such as current, water flow rates, SMA predisplacement, and gauge pressure of the compressed air, are identified from the SMA thermal model and from the actuation mechanism. In-depth modeling and characterization have been performed regarding these parameters to optimize the robot motion speed. Forced water cooling has also been compared with forced air cooling and proved to be the superior method to achieve higher robot speed. An improved robot design and a magnetic-resonance-imaging-compatible experimental platform have been developed for the implementation of the actuation mechanism. [ABSTRACT FROM PUBLISHER]

The design of a multiple-segment notched tube is distinctively appropriate for miniature surgical robots, attributing to its superior structural compliance and the provision of a substantial lumen within a constrained diameter. However, the cable-driven mechanism commonly adopted in this design naturally leads to inter-segment motion coupling, limiting its clinical potential. This study introduces a model-based design optimization method aimed at concurrently minimizing the coupled motion of a two-segment notched flexible robot and meeting diverse design and performance criteria. In the design optimization framework, a single-segment mechanics model, a 3-dimensional (3D) coupled mechanics model, and a 3D stiffness model have been developed and integrated to simultaneously minimize the coupled bending angle and satisfy surgery-specific performance requirements. A back propagation neural network (BPNN) has also been adopted to achieve computationally efficient optimization process. A case study is conducted on two-segment notched flexible robot optimization design for maxillary sinus surgery, with the mechanics models being verified experimentally. Ultimately, the optimized robot demonstrates its ability to provide visualization of the maxillary sinus cavity, including the blind spots. The proposed robot design optimization approach offers a systematic and efficient methodology to minimize motion coupling without compromising robot performance, thus fundamentally enabling procedure-specific design of multi-segment flexible surgical robots. [Display omitted] • Established a mechanics model with coupled motion of a 2-segment flexible robot. • Established a stiffness model that considers the tip payload. • Proposed a model-based design optimization method for 2-segment flexible robot. • Introduced a back propagation neural network to approximate the mechanics model. • Demonstrated effectiveness of the design optimization method in sinus surgery. [ABSTRACT FROM AUTHOR]