Milli-spinner x Stroke: Unprecedented Technology Spins Inside Arteries Removing Clots and Saving Lives in Minutes

Stanford scientists have created a new device called a milli-spinner, which works like a micro-drill to quickly and safely remove blood clots during a stroke. It is more effective than current methods and could double the chances of success, helping to save lives with fewer risks and complications.

A new technology developed by engineers at Stanford University promises to transform the way blood clots are removed during medical emergencies such as ischemic stroke.

These clots block the flow of oxygen to the brain and need to be removed as quickly as possible to prevent serious damage and even death.

The new device, dubbed the “milli-spinner,” works like a tiny drill that spins rapidly inside the blood vessel, pulling and compacting the clot safely and efficiently.

Unlike current methods, which attempt to suck or trap the clot, often breaking it up and spreading dangerous fragments to other parts of the body, the milli-spinner takes a novel approach.

It precisely spins and squeezes the clot, “squeezing” the red blood cells out of the protein meshwork called fibrin. This meshwork is the main component that gives the clot its firmness. Afterward, what’s left is a small, compacted “core” of fibrin, which the device can easily remove.

The image shows how the new milli-spinner device works to remove blood clots during events such as stroke, heart attack and thrombosis. Initially, the clot consists of a loose network of fibers and red blood cells (top right), similar to a cotton ball. The milli-spinner spins inside the blood vessel, like a small drill, applying force to compress and compact the clot (middle of the image). This transforms the loose network into a much denser and smaller mass that can be easily removed without breaking into dangerous pieces. The hand comparison (right) shows the visual difference between the clot before and after compaction. The last image (bottom) shows the actual device at a reduced scale.

This technique has demonstrated impressive results. In tests, the milli-spinner was able to completely remove even the most stubborn clots on the first attempt in 90% of cases, a significant improvement considering that current devices achieve this feat in only 11% of the most difficult cases.

Milli-spinner in action

This means more chances of saving lives and less time wasted during the treatment of serious conditions such as strokes, heart attacks, pulmonary embolisms and thrombosis.

The idea behind the milli-spinner came about by chance, from studies of small origami-inspired robots that moved around inside the body.

When the researchers tested the prototype’s suction motion on a clot, they were surprised to see that it not only pulled blood out, but also dramatically shrank the clot, changing its color from red to white. This discovery led to the refinement of the device over hundreds of tests.

Stanford professors Jeremy J. Heit and Renee Zhao demonstrate the insertion of the milli-spinner into a life-size circulatory model.

In addition to revolutionizing the treatment of brain clots, the scientists believe the milli-spinner could be used in the future to treat other conditions, such as kidney stone fragments or peripheral vein obstructions.

The team behind the technology has already begun the process of getting the technology into hospitals and into real patients. They have created a company licensed by Stanford University to expedite the process of approval and clinical use.

The image shows how blood flow was restored after the milli-spinner removed the clot in pulmonary (a-c) and cerebral (d-e) vessels.

In the future, this small device could represent a giant leap forward in emergency medicine. With its ability to act quickly, accurately and with fewer complications, the milli-spinner has the potential to save millions of lives by offering a smarter, more effective approach to one of medicine’s greatest challenges: combating dangerous clots.

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Milli-spinner thrombectomy

Yilong Chang, Shuai Wu, Qi Li, Benjamin Pulli, Darren Salmi, Paul Yock, Jeremy J. Heit, and Ruike Renee Zhao 

Nature. 04 June 2025

https://doi.org/10.1038/s41586-025-09049-0

Abstract:

Clot-induced blockage in arteries or veins can cause severe medical conditions1. Mechanical thrombectomy is a minimally invasive technique used to treat ischaemic stroke, myocardial infarction, pulmonary embolism and peripheral vascular disease2,3,4 by removing clots through aspiration5, stent retriever6 or cutting mechanisms7. However, current mechanical thrombectomy methods fail to remove clots in 10–30% of patients8,9,10, especially in the case of large, fibrin-rich clots11. These methods can also rupture and fragment clots12, causing distal emboli and poor outcomes13. To overcome these challenges, we develop the milli-spinner thrombectomy, which uses a simple yet innovative mechanics concept to modify the clot’s microstructure, facilitating its removal. The milli-spinner works by mechanically densifying the clot’s fibrin network and releasing red blood cells through spinning-induced compression and shear forces. It can shrink the clot volume by 95% for easy and fast removal. In vitro tests in pulmonary and cerebral artery flow models and in vivo experiments in swine models demonstrate that the milli-spinner achieves ultrafast clot debulking and high-fidelity revascularization, outperforming aspiration thrombectomy. The milli-spinner thrombectomy directly modifies the clot microstructure to facilitate clot removal, improving mechanical thrombectomy success rates compared with current methods that rely on clot rupture or cutting. This approach offers a promising new direction for mechanical thrombectomy devices, especially for treating ischaemic stroke, pulmonary embolism and peripheral thrombosis.