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Magellan Ureteral Access Sheath
Magellan Ureteral Access Sheath
Ureteral Access Sheath
A ureteral access sheath is part of the urologist’s armamentarium for retrograde intrarenal surgery (RIRS). It can help reduce the need for repeated reinsertion and withdrawal of ureteroscopes, thereby improving the flow of irrigation and visualization within the urethra during RIRS. However, the effect of a sheath on stone-free rates, risk of ureteral strictures, and perioperative complications such as postoperative pain and ureteroscope injury remains unknown.
Until recently, data on the effectiveness of sheaths were inconclusive. In fact, until 2018, there was insufficient evidence to support the use of a sheath, with reported benefits such as increased irrigation outflow and lower intrarenal pressures during RIRS [1,2].
The Magellan Sheath is an innovative ureteral access sheath system combining a dual durometer sheath with a lubricious inner dilator that glides smoothly through tortuous anatomy while resisting kinking and buckling, allowing for atraumatic passage of endoscopes and retrieval devices. The sheath has a clear coating that gradually transitions to blue, enabling ureologists to visualize their progress in the urethra and ureter. The sheath’s hydrophilic coating is combined with a dilator made of a stainless steel coil reinforced with carbon to confer resistance to kinking and buckling.
In a new study, researchers compared the Magellan Sheath to a competing sheath from another manufacturer. They analyzed the sheaths’ ability to resist buckling and kinking, their tip flexibility and sheath insertion force. The sheaths were tested in pigs with complex upper urinary tract anatomy and used for a variety of procedures, including laser lithotripsy and basket extraction. The researchers found that the sheaths were equally flexible and required similar forces for insertion. The sheaths’ inner dilator tips, on the other hand, demonstrated different stiffnesses. The PW sheath had the softer inner dilator tip, requiring less force for bending and buckling experiments, while the GW and NHD sheaths had stiffer inner dilators, requiring more force to bend and buckle.
The researchers also compared the sheaths’ ability to resist tip perforation and dilator removal in the pigs. They performed a series of tip flexibility experiments with each sheath, with the dilator secured in a 2 mm divot in a wooden block and the stage advanced 1 cm while recording maximum force for sheath buckling and bending. The sheaths’ insertion forces were also recorded, with the GW sheath requiring 7 times more force for dilator removal than the NHD sheath. These results suggest that the sheath’s dilator tip may be more likely to cause ureteral perforation than a competing sheath with a more resilient inner dilator. The research was funded by Boston Scientific.
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