SELF-STRAIGHTENING NEEDLE ASSEMBLY

Systems comprising a needle assembly configured to be inserted and steered within the brain, body tissue, or cavity, for the purpose of performing a surgical procedure. The needle assembly comprises robotically controlled and motorized concentric cannulas. For bending, there may be provided, for example, a tensioning wire configured to bend an inner cannula, or a cannula with an adjustable natural curve. A flexible inner element passing through the bend of the inner cannula is made self-straightening to minimize susceptibility to displacement from its intended path as it is advanced through the tissue. The self-straightening inner element comprises, for example, at least one of a super-elastic tube, a shape-memory alloy tube, a slotted tube, a tightly coiled memory alloy spring, circular links held together by pulling cables preloaded by springs, and a notched inner cannula with a cable connected via a loaded spring to tension the inner cannula.