Strokes are one of the leading causes of death and long-term disability worldwide. In ischemic strokes, which account for 90% of cases, a blood clot blocks the flow of oxygen to at least one area of the brain, and every second counts. Traditional treatment methods, such as intravenous clot-dissolving drugs (tPA) and mechanical thrombectomy, have made major strides, but they still fail or are incomplete in a significant subset of patients.

Recently, a team of researchers at Stanford University unveiled a new device called the milli-spinner thrombectomy. This device re-imagines clot removal by mechanically shrinking and extracting clots more effectively than existing tools. Early tests suggest this is not a marginal improvement, but a shift in the way that stroke patients receive early treatment in the moments that matter the most.

What Is the Milli-Spinner and How Does It Work?

Unlike earlier thrombectomy techniques that attempt to vacuum out or snare the clot, the milli-spinner employs a rotating hollow tube fitted with fins and slits that apply compression and shear forces to restructure and shrink the clot. The result is that the clot, which was once a large, fibrous mass, becomes significantly smaller, easier to remove, and less prone to releasing harmful fragments.

In flow-model and animal-model tests, the device reduced clots to as little as 5 % of their original volume and achieved first-pass revascularization rates of up to 90 %, compared with around 50 % for current technologies and much lower for particularly tough fibrin-rich clots.

The innovation behind the milli-spinner lies not only in its rotational mechanism but also in its precision micro-engineering. Measuring less than a millimeter in diameter, the device is small enough to navigate the brain’s intricate vascular network without damaging vessel walls. It’s powered by a flexible micro-motor system that allows physicians to control both rotation speed and torque with exceptional accuracy. Unlike suction-based systems that risk collapsing delicate vessels, the milli-spinner gently reshapes the clot from within, reducing both trauma and the likelihood of clot remnants being left behind.

This level of precision control is what allows it to work effectively even in small, distal arteries that are often unreachable by standard thrombectomy devices, potentially expanding treatment options for patients previously considered ineligible for intervention.

Why This Matters: The Limitations of Current Treatments

Current stroke treatment methods, while life-saving, still leave significant room for improvement. Intravenous clot-busting drugs such as tissue plasminogen activator (tPA) can only be administered within a narrow time window. Generally, this medication has to be administered within 4.5 hours of initial stroke symptoms. It’s also considered less effective for patients with large or dense clots.

Mechanical thrombectomy devices, such as stent retrievers and aspiration catheters, have revolutionized care for large-vessel occlusions, but their success rates remain inconsistent. Many procedures require multiple attempts to clear the clot completely, and in nearly 1/3 of cases, portions of the blockage remain or new fragments migrate deeper into the brain, causing secondary strokes or extended neurological damage.

The challenge lies in the nature of clots themselves. Fibrin-rich clots, which are tougher and more elastic, can adhere stubbornly to arterial walls and resist the suction or pulling forces used by current devices. Moreover, each additional pass of a thrombectomy tool increases the risk of vessel injury, bleeding, or inflammation. For patients, this means longer operating times and less predictable outcomes, even when treated by experienced neurointerventional teams. As a result, physicians have long sought a tool that can reliably remove clots in a single pass, minimizing both mechanical trauma and ischemic delay.

The milli-spinner addresses these shortcomings by rethinking the physics of clot extraction. Instead of relying solely on suction or retrieval, it gently compresses and disassembles the clot through rotational motion, effectively reducing its size before removal. This design allows it to extract even dense fibrin-rich clots with minimal risk of fragmentation. Early research also suggests that the milli-spinner could shorten procedure times, restore blood flow more completely, and reduce complications linked to vessel damage or incomplete removal. In a field where every minute can mean millions of neurons lost, a faster and safer alternative could dramatically improve recovery outcomes and survival rates.

Potential Applications Beyond Stroke

While the focus is on ischemic stroke, the milli-spinner’s mechanism holds promise for other clot-related conditions. These conditions include heart attacks and pulmonary embolisms. It even has the potential to be used for patients with kidney stones. The researchers are already exploring “untethered” versions of the device and broader biomedical applications. This expansion potential makes the innovation especially exciting. A device invented to reshape clots in the brain may become a platform technology tackling a variety of vascular and non-vascular blockages. This could not only reshape how patients receive life-saving care, but could also impact how non-critical health problems are treated.

Challenges Ahead: From Lab to Clinic

While the early results are promising, several steps remain before this new device sees widespread clinical use. The milli-spinner must undergo human clinical trials to confirm safety, efficacy, and durability in patients, not just flow models or animal subjects. Regulatory approval, manufacturing scale-up, cost assessment, and training of interventional teams will be significant hurdles.

The mill-spinner thrombectomy device developed at Stanford may represent one of the most promising advances in endovascular stroke treatment in years. By rethinking the mechanics of clot removal, the device addresses persistent failure modes and offers meaningful gains in first-pass success. While hurdles remain on the path to clinical adoption, the potential benefits for patients, clinicians, and health systems are substantial. As trials begin and real-world use unfolds, the focus may shift from whether the device will work to how it will impact patient care.