High-curvature Flexible Needle Design and Embodied Perception Method for Interaction Risk Assessment

Intracranial intervention in brain tissue requires flexible needles with high-curvature deformation capability for dexterous steering, but excessive curvature may cause interaction risks such as tissue rupture. This contradiction constitutes the core challenge for flexible needles in pursuing high-curvature deformation while ensuring safe operation, necessitating both an embodied new morphology with dexterous and safe operation capabilities and an embodied perception ability for risk assessment. This study proposes a three-layer coaxial progressive flexible needle featuring a bevel-tip and torque-transmitting sheath coupling structure, synergistically utilizing the passive steering feature of bevel tip and the high torsion and low bending stiffness features of transmitting sheath to achieve high-curvature deformation. An interaction state perception mechanism based on strain energy variation is integrated with fiber Bragg grating shape reconstruction, enabling real-time detection of interfacial mechanical state transition risks. Gelatin puncture experiments demonstrate that the proposed needle achieves a maximum curvature of 0.022\; 1\; \mathrmmm^-1 with real-time quantitative feedback of needle-tissue interaction state. This study provides a flexible intervention solution for minimally invasive neurosurgery with both dexterous operation and interaction risk assessment capabilities.