The current trend of the contemporary medicine is less invasiveness and local
therapy. One of the most common procedures employed in modern clinical practice
involve percutaneous insertion of needles and catheters for biopsy and drug
delivery. Percutaneous procedures involving needle insertions include
vaccinations, blood/ ﬂuid sampling, regional anesthesia, tissue biopsy, catheter
insertion, cryogenic ablation, electrolytic ablation, brachytherapy,
neurosurgery, deep brain stimulation, minimally invasive surgeries and more.
These problems can be solved by introducing thin and flexible needles. Moreover, it is known that thinner needles cause less pain to the patient. On the other hand, flexible needle navigation deep inside the tissue is very complicated. The system has non-minimum phase behavior and is not intuitive to control. Path planning for flexible needle insertion and obstacles avoidance inside the body tissue is a challenging problem in mechanics and robotics. Creating an automated system that can plan and perform thin, flexible needle insertion will minimize misplacements, reduce risks, and reduce patient suffering.
Flexible needle insertion into viscoelastic tissue is formulated by a linear beam supported by virtual springs. Using this simplified model, the forward and inverse kinematics of the needle is solved analytically, providing a way for simulation and path planning in real-time. Using the inverse kinematics, the required needle basis trajectory can be computed for any desired needle tip path.