Novel Needle Could Reduce Medical Complications

A new needle, based on concepts borrowed from the oil industry, aims to prevent hypodermic needles from penetrating too far under their skin by keeping them "on target."

Researchers from the Massachusetts Institute of Technology (MIT; Cambridge, MA, USA) developed the new needle, which involves a hollow S-shaped needle containing a filament that acts as a guide wire. When a physician pushes the device against a tissue, force is applied to the filament, not the needle itself, due to a special clutch mechanism. When the filament, which moves through the tip of the needle, encounters resistance from a firm tissue, it begins to buckle within the S-shaped tube.


Due to the combined buckling and interactions with the walls of the tube, the filament locks into place, and the needle and wire advance as a single unit. The needle and wire then proceed through the firm tissue. However, once they reach the target cavity (for example, a blood vessel) there is no more resistance on the wire, and it quickly advances forward while the needle remains stationary. Because the needle is no longer moving, it cannot proceed past the cavity into the wrong tissue. A similar locking phenomenon has long been observed in drill strings inside drill shafts used by the oil-drilling industry. The study describing the new technology was published in the April 7, 2009, issue of the Proceedings of the [U.S.] National Academy of Sciences (PNAS).

Insertion of trocars, needles, and catheters into unintended tissues or tissue compartments results in hundreds of thousands of complications annually. Current methods for blood vessel cannulation or epidural, chest tube, and initial trocar placement often involve the blind pass of a needle through several layers of tissue and generally rely on anatomic landmarks and a high degree of clinical skill.

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