Nested Needle Assembly for Vagus Nerve Stimulation

The patent employs a nested needle assembly where an inner needle with imaging elements is positioned within an outer needle. The inner needle contains echogenic elements and ferromagnetic elements that provide visualization capabilities, while the outer needle provides structural support and tissue access. This nested configuration enables advanced imaging and tracking functions without requiring entirely separate devices, thus improving positioning accuracy while controlling equipment complexity.

The patent introduces imaging elements as intermediaries between the needle and the imaging system. Echogenic elements reflect ultrasound waves to create visible signals, while ferromagnetic elements interact with magnetic fields for tracking. These intermediary elements translate the physical presence of the needle into detectable signals, enabling real-time visualization and precise positioning without directly complicating the needle structure itself.

The patent combines multiple imaging functionalities within a single integrated needle assembly. Both echogenic elements (for ultrasound imaging) and ferromagnetic elements (for magnetic tracking) are incorporated into the same inner needle, allowing simultaneous or alternative use of different imaging modalities. This merging approach provides comprehensive real-time visualization while avoiding the need for multiple separate imaging devices, thus reducing overall system complexity.

The inner needle serves multiple functions: it provides structural support, contains imaging elements for visualization, and enables both ultrasound and magnetic tracking capabilities. This multi-functional design eliminates the need for separate specialized devices for each imaging modality, reducing device complexity while maintaining comprehensive real-time imaging capabilities.

The patent employs a dynamic needle assembly where the inner needle can be extended or retracted relative to the outer needle. The sharp inner needle is extended only when tissue penetration is required, and retracted when passing through the carotid sheath or during lead deployment. This dynamic configuration allows the system to switch between high penetration capability and low tissue damage states as needed, resolving the contradiction between cutting effectiveness and tissue safety.

The patent uses the sharp inner needle to create a preliminary puncture path through the skin and subcutaneous tissue before the outer needle is advanced. Once the initial path is established, the inner needle is retracted and the outer needle (with blunt tip) is advanced through the created tract. This preliminary action allows the sharp needle to do its cutting work only where necessary, minimizing overall tissue damage while achieving effective penetration.