Estimation of flexible needle deflection in layered soft tissues with different elastic moduli

Area of Science:

• Biomedical Engineering
• Robotics
• Medical Device Development

Background:

• Needle steering in biological tissue is complex due to tissue heterogeneity.
• Previous models often used simplified homogeneous tissue assumptions, limiting accuracy.
• Biological tissues possess layered structures with varying mechanical properties.

Purpose of the Study:

• To develop and validate a novel needle deflection model for double-layered elastic media.
• To improve the accuracy of needle steering in anatomically realistic, multi-layered tissues.
• To account for varying friction, cutting forces, and stiffness in layered tissues.

Main Methods:

• Proposed a needle deflection model utilizing a double-layered elastic medium.
• Employed the Rayleigh-Ritz method for analytical estimation of needle deflection.
• Conducted validation experiments using double-layered tissue phantoms and porcine tissues.

Main Results:

• Observed distinct changes in reaction force at the needle base when crossing layer boundaries.
• Achieved a mean absolute error of 0.88 ± 0.30 mm for phantom tissues.
• Attained a mean absolute error of 1.85 ± 0.73 mm for porcine tissues, comparable to homogeneous models.

Conclusions:

• The proposed double-layered model enhances the prediction of needle deflection in heterogeneous biological tissues.
• This model offers improved precision for needle steering interventions in complex anatomical structures.
• The findings suggest potential for more accurate robotic-assisted surgeries and biopsies.