Ureteral Stents (AF-D series)

The Ureteral Stents (AF-D series) are flexible, double-pigtail stents made of thermoplastic polyurethane with hydrophilic coating, used for temporary internal drainage from the ureteropelvic junction to the bladder in patients with benign, malignant, or post-traumatic obstruction. The stents are placed via endoscopic, percutaneous, or open surgical techniques and must be removed within 30 days.

The subject device differs from the predicate (Cook Universa Soft Stents) in several ways: it offers 4Fr diameter (predicate offers 5-8Fr), different stent lengths (8-28cm vs 8-30cm), lacks the predicate's radiopaque-tipped introducer and suture tether features, and uses different guidewire diameters (0.025" for 4/5Fr; 0.035" for 6/7Fr versus predicate's 0.035-0.038"). Both are double-pigtail designs sterilized by EtO for single use.

ISO 10993-1 for biocompatibility testing; ISO 11135:2014 for ethylene oxide sterilization achieving SAL 10⁻⁶; FDA guidance on 'Guidance for the Content of Premarket Notification for Ureteral Stents' (1993) for bench performance testing protocols.

Although the devices have different technological characteristics (diameter range, introducer design, guidewire specifications), comprehensive bench performance testing demonstrated that the subject device meets or exceeds predicate performance on curl retention, break strength, flow rate, friction force, kink stability, insertion/removal simulation, and chemical properties. Biocompatibility testing showed no safety concerns. The identical indications for use, similar double-pigtail design, common sterilization method, and equivalent safety and performance profile despite design differences establish substantial equivalence.