A Continuum Manipulator with Variable Curvature for Electrocautery Hemostasis in Spinal Endoscopic Surgery: Design, Modeling and in Vivo Validation

Spinal endoscopic surgery is a representative minimally invasive technique for the treatment of spinal disorders, but the narrow operative corridor and constrained workspace impose high requirements on the dexterity and accessibility of surgical instruments, especially for electrocautery hemostasis. To address the limitations of conventional electrocautery instruments in complex surgical regions, this paper proposes a variable-curvature continuum electrocautery surgical manipulator for spinal endoscopic surgery. The proposed manipulator adopts a modular design integrating an electrocautery tool, a flexible distal segment, and a proximal actuation mechanism, and achieves distal bending, curvature adjustment, axial translation, and overall rotation through tendon-driven actuation. A constant-curvature kinematic model is established to describe the tip pose, and a workspace analysis is conducted to evaluate the reachable region of the manipulator. In addition, an intuitive master-slave mapping method based on a master device is developed to improve teleoperation performance. A prototype of the proposed manipulator is fabricated, and in vivo animal experiments are conducted to validate its operational feasibility and hemostatic effectiveness. The experimental results demonstrate that the proposed manipulator can achieve precise targeting and safe electrocautery hemostasis in complex tissue environments, indicating its potential application in minimally invasive spinal endoscopic surgery.