Wire-driven flexible manipulator with constrained spherical joints for minimally invasive surgery

A flexible cystoscopy device prototype for mechanical tissue ablation based on micro-scale hydrodynamic cavitation: Ex vivo and in vivo studies

Minimally invasive methods were sought for faster recovery from benign prostatic hyperplasia (BPH) and lower urinary tract (LUTS) symptoms. For this, the search for effective, low-side-effect methods for tissue ablation, particularly for managing BPH and certain bladder pathologies, has been continued to advance. In this regard, the energy released during the formation of hydrodynamic cavitation bubbles offers an alternative treatment method. In this study, we present the feasibility of the use of hydrodynamic cavitation with a flexible cystoscopy device prototype designed for the treatment of LUTS-related diseases. The developed flexible cystoscopy device prototype allows easy access to the urinary bladder through urethra with minimal pain, demonstrating its suitability as a minimally invasive approach. Precisely targeted cavitation exposure prevents prostatic capsule and bladder perforation. Moreover, an automatic actuating mechanism supports steering for real-time visual feedback. The developed device prototype was first tested on an ex vivo human bladder and then on an in vivo porcine bladder. Histopathological analyses were performed after both species were tested. For both analyses, significant tissue ablation at the targets was observed upon exposure to cavitating flows. Finally, the temperature profile on the device was obtained using a thermal camera. Accordingly, it was observed that the temperature increase during the procedure was not significant. The developed device prototype can thus realize mechanical ablation-based therapy, avoids unintended heat deposition which might appear in laser ablation and leads to fewer side effects such as uncontrolled tissue damage and low target area effectiveness that might occur in minimally invasive tissue ablation methods.

A review of wrist mechanism design and the application in gastrointestinal minimally invasive surgery of multi-degree-of-freedom surgical laparoscopic instruments

BACKGROUND

This paper aims to comprehensively review current designs of Multi-degree-of-freedom (Multi-DOF) wrist mechanisms and the applications of Multi-DOF surgical instruments in gastrointestinal minimally invasive surgery (MIS).

METHODS

By reviewing the advantages and limitations of traditional laparoscopic and robotic surgical instruments, we present the development of Multi-DOF surgical instruments. Then, we summarize the Multi-DOF wrist mechanisms, delineating their pros and cons. Finally, the surgical outcomes and efficiency of Multi-DOF surgical instruments are reviewed.

RESULTS

The utilization of Multi-DOF surgical instruments for both benign and malignant gastrointestinal diseases demonstrates perioperative outcomes comparable to traditional laparoscopic and robotic surgeries. In certain aspects, it exhibits advantages such as shorter operative times and faster gastrointestinal function recovery.

CONCLUSION

Further research is needed to effectively combine these driving mechanisms to achieve a new type of transmission mechanism with high rigidity and precision, ample working space, and decoupled degrees of freedom. Multi-DOF surgical instruments offer the advantages of high flexibility and lower costs, displaying good feasibility and safety in practical clinical applications within gastrointestinal surgery. Their promotion in primary care hospitals could benefit a larger patient population. However, more extensive sample-sized multicenter studies are still warranted to elucidate such surgical instruments' advantages further.

Experimental validation of manipulability optimization control of a 7-DoF serial manipulator for robot-assisted surgery

PURPOSE

Both safety and accuracy are of vital importance for surgical operation procedures. An efficient way to avoid the singularity of the surgical robot concerning safety issues is to maximize its manipulability in robot-assisted surgery. The goal of this work was to validate a dynamic neural network optimization method for manipulability optimization control of a 7-degree of freedom (DoF) robot in a surgical operation.

METHODS

Three different paths, a circle, a sinusoid and a spiral were chosen to simulate typical surgical tasks. The dynamic neural network-based manipulability optimization control was implemented on a 7-DoF robot manipulator. During the surgical operation procedures, the manipulability of the robot manipulator and the accuracy of the surgical operation are recorded for performance validation.

RESULTS

By comparison, the dynamic neural network-based manipulability optimization control achieved optimized manipulability but with a loss of the accuracy of trajectory tracking (the global error was 1 mm compare to the 0.5 mm error of non-optimized method).

CONCLUSIONS

The method validated in this work achieved optimized manipulability with a loss of error. Future works should be introduced to improve the accuracy of the surgical operation.