Schematic of ureteroscopic laser lithotripsy and the magnetic stone retrieval system. Credit score: Machine (2025). DOI: 10.1016/j.system.2025.100971
Stanford College has unveiled a ureteroscopy-compatible system that magnetizes and retrieves kidney stone fragments with a wire, with efficiency in a pig mannequin beating conventional elimination methods.
Kidney stone illness impacts round 11% of the US inhabitants and sometimes requires ureteroscopic laser lithotripsy. Fragment elimination after lithotripsy stays inefficient, leaving many sufferers with residual items that may set off ache, an infection, repeat procedures, and added prices.
Stones kind from crystallized salts that may then hinder the skinny tubes that carry urine from the kidneys to the bladder, inflicting ache, an infection, and kidney harm.
Ureteroscopic laser lithotripsy stays the commonest process. An endoscope enters by means of the urethra to the higher urinary tract, a laser fiber breaks stones into fragments beneath saline irrigation, and surgeons then goal for elimination or spontaneous passage of small items.
Residual fragments persist in as much as 40% of sufferers after ureteroscopy, driving issues that vary from emergency visits to repeat interventions. Danger accumulates with time, as 30% of sufferers with any residual fragments required one other operation inside 5 years, in contrast with 4% amongst these with no residual items.
Care calls for are substantial, with greater than 1.3 million emergency visits and greater than $4 billion in annual expenditures within the US. Coupled with rising weight problems and diabetes, main danger elements for formation, kidney stones are estimated so as to add one other $1.2 billion per 12 months in well being care prices by 2030.
Within the examine, “Magnetic retrieval of kidney stones via ureteroscopy in a porcine model,” revealed in Machine, researchers engineered a ureteroscopy-compatible system to magnetize stone fragments with a hydrogel and retrieve them utilizing a magnetic wire beneath direct endoscopic visualization in pigs.
Magnetic seize of kidney stone fragments in an ex vivo mannequin. Credit score: Machine (2025). DOI: 10.1016/j.system.2025.100971
Experimental setups
Devices mirrored these utilized in medical ureteroscopy with some managed optimization. A 3D-printed kidney mannequin was positioned in a 0.9% saline bathtub. Human-derived kidney stone fragments had been positioned within the mannequin kidney.
Two hydrogel precursors, ferumoxytol and chitosan, had been co-delivered by means of the dual-lumen injector in order that they contacted on the fragment floor and fashioned the magnetic hydrogel in situ, after which the magnetic wire tried retrieval.
Pig kidneys obtained retrograde placement of human-derived calcium oxalate fragments beneath 3 mm, magnetic hydrogel was delivered onto the fragments, and the magnetic wire tried retrieval. Management kidneys underwent fragment placement and basket retrieval solely.
Survival experiments used three pigs. One kidney per animal obtained magnetic hydrogel with endoscopic affirmation of gel formation, and the contralateral kidney remained untreated as a management.
3D-printed kidney outcomes
Benchtop optimization recognized an preliminary density mismatch between ferumoxytol and chitosan in saline. Addition of glycerol to the chitosan precursor matched densities and elevated magnetic labeling of 1–2 mm calcium oxalate fragments by four-fold.
Ureteroscopy runs demonstrated multi-fragment elimination after a single hydrogel software. A complete of 28 fragments sized 1–2 mm had been eliminated in six passes following roughly 100 μL ferumoxytol and 200 μL chitosan delivered by means of the injector.
Efficiency in pigs
One-week survival experiments recorded uneventful stone-free restoration with regular urination. Urinalysis and bloodwork remained inside regular ranges.
Irrigation alone cleared about 70% of the instilled gel. Mixed magnetic retrieval and irrigation cleared 99.8% of the gel inside 10 minutes. Magnetic particle imaging of urine, blood, kidneys, ureters, bladder, and chosen organs at one week confirmed indicators under the detection restrict, supporting full elimination of the hydrogel by that point level.
Future analysis plans
The authors conclude {that a} magnetize-and-retrieve technique is possible and appropriate with medical ureteroscopes in a porcine mannequin, with a positive short-term security profile and demonstrable pathways for intraoperative elimination and physiologic clearance.
Future plans embrace head-to-head testing in a ureteroscopy mannequin, hydrogel formulation refinement towards simplified dosing ratios, catheter enhancements, and exploration of alternate magnetic geometries.
Profitable translation to a medical technique may increase stone-free elimination charges, cut back affected person opposed outcomes and decrease well being care burdens.
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Extra data:
Magnetic Retrieval of Kidney Stones through Ureteroscopy in a Porcine Mannequin, Machine (2025). DOI: 10.1016/j.system.2025.100971. www.cell.com/system/fulltext/S2666-9986(25)00284-4
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Magnetized strategy to kidney stone retrieval outperforms commonplace strategies in preclinical examine (2025, November 4)
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