Distal Bevel-Tip Needle Steering via Kinematic Control
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Solution Overview
Problem
Rigid surgical needles face challenges in accurate and precise insertion due to tissue deflection and deformation, particularly in prostate cancer, liver cancer, and intracranial hemorrhage treatments, where mechanical properties of tissues differ significantly, leading to inaccurate needle placement and complications.
Innovation Solution
A distal bevel-tip needle control device and algorithm that uses software-based control models and image-based position feedback to steer the needle within a tissue medium, employing a combination of translation and rotation actuators, encoders, and a processor to compute a needle path based on tissue mechanical properties, allowing for precise control and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid needles are used for needle insertion, then structural strength is improved, but needle placement precision deteriorates due to tissue deflection and deformation
Solution Approach 1:
The needle is divided into two functional segments: a rigid proximal portion for strength and a flexible distal portion for steering. The distal bevel-tip segment can be rotated and translated independently to steer the needle tip through tissue while the proximal portion maintains structural integrity for force transmission.
Solution Approach 2:
The needle transitions from a static rigid structure to a dynamic system where the distal portion can be actively steered through translation and rotation actuators. This allows real-time adjustment of needle orientation and position to compensate for tissue deflection during insertion.
2Ease of operation
If hand-inserted rigid needles are used, then ease of operation is improved, but needle placement accuracy deteriorates due to inability to steer through tissue
Solution Approach 1:
Manual hand-insertion is replaced with an automated control system comprising translation actuators, rotation actuators, encoders, and a processor. This robotic system provides precise control of needle position and orientation while the surgeon maintains operational control through the interface system.
Solution Approach 2:
Position encoders provide real-time feedback on needle tip location and orientation. This feedback is processed to compute the current needle state and guide further actuator commands, enabling closed-loop control that maintains placement accuracy throughout the insertion process.
3Force
If rigid needles are used to penetrate tissue, then force transmission is improved, but tissue deflection complicates needle guiding
Solution Approach 1:
The needle is segmented into a rigid proximal portion for force transmission and a flexible distal portion for steering. This segmentation allows the rigid segment to maintain force integrity while the flexible distal segment adapts to tissue contours for accurate targeting.
Solution Approach 2:
The system dynamically adjusts control parameters including translation speed, rotation angle, and actuator force based on real-time encoder feedback and tissue response. This adaptive parameter adjustment simplifies the guiding process by automatically compensating for tissue deflection.
4Adaptability or versatility
If multiple rigid needles are inserted for different angles, then treatment coverage is improved, but procedure time increases due to removal and reinsertion
Solution Approach 1:
A single needle system provides multi-functionality by enabling insertion from multiple angles and positions through automated steering. The same needle can be reused for different treatment trajectories by adjusting actuator commands, eliminating the need to remove and reinsert multiple needles.
Solution Approach 2:
The needle maintains continuous insertion through automated translation and rotation actuators that guide it through different angles without removal. This continuous action maintains treatment coverage while eliminating idle time between insertions, significantly reducing overall procedure time.
Data Source
AI summary
Disclosed is a system for percutaneously steering a surgical needle. Needle steering is accomplished by taking advantage of a deflection force imparted on the bevel tip of the needle by the tissue medium as the needle is pushed through the tissue. By controlling the translation speed and rotation angle of the bevel, a flexible needle may be steered substantially without deflecting or distorting the tissue. The control inputs (translation speed and rotation angle) are computed based on a “bicycle” non-holonomic kinematic model that is a function of mechanical properties of the tissue medium. The system may be used with image-based feedback, which may provide for feedback-based refinement of the model as the needle propagates through the tissue.