1、Designation: F1828 97 (Reapproved 2014)F1828 17Standard Specification forUreteral Stents1This standard is issued under the fixed designation F1828; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe objective of this specification is to describe the test methods used to evaluate the safety andeffectiveness of an indwelling ureteral st
3、ent, having retention means at the kidney and bladder ends,used for urinary drainage of the kidney to the bladder via the ureter.This specification includes referee test methods that can be used to evaluate the performancecharacteristics of ureteral stents. Note that the test methods are not to be c
4、onstrued as productionmethods, quality control techniques, or manufacturers lot release criteria. The product parametersaddressed by the standard include those determined by the ASTM task group to be pertinent to theproduct.1. Scope1.1 This specification covers the referee test methods for evaluatin
5、g the performance characteristics of a single-use ureteral stentwith retaining means at both ends, during short term use for drainage of urine from the kidney to the bladder. These stents aretypically available in diameters of 3.7 Fr to 14.0 Fr, and lengths of 8 cm to 30 cm, and are made of silicone
6、, polyurethane, andother polymers. They are provided non-sterile for sterilization and sterile for single-use.1.2 ExclusionsLong-term indwelling usage (over 30 days) is encountered with this product, but not commonly, and istherefore considered an exception to this specification. Similarly, the use
7、of ureteral stents for non-ureteral applications such asnephrostomy and ileostomy is excluded from the scope of this specification. Non-sterile ureteral stents are also excluded due tothe variability of hospital sterilization equipment and processes and the resulting effects on ureteral stent charac
8、teristics.1.3 The following precautionary statement pertains only to the test method portion, Section 5, of this specification:1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish
9、appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of Inte
10、rnational Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D412 Test Methods for Vulcanized Rubber and Thermoplastic ElastomersTensionF640 Test Methods for Determining Radiopacity for Me
11、dical UseF748 Practice for Selecting Generic Biological Test Methods for Materials and Devices3. Terminology3.1 Definitions of Terms Specific to This Standard:1 This specification is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsi
12、bility of SubcommitteeF04.34 on Urological Materials and Devices.Current edition approved Oct. 1, 2014March 1, 2017. Published November 2014April 2017. Originally approved in 1997. Last previous edition approved in 20062014as F1828 97F1828(2006). 97 (2014). DOI: 10.1520/F1828-97R14.10.1520/F1828-17.
13、2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to
14、 provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof
15、 the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 artificial urinetest media a(1) solution of organic and inorganic compounds thatsaline, an isotonic sol
16、ution of pH 5.5to 7.0; or closely(2) simulates the chemical and physical properties of normal human urine. Artificial urine will be used as asubstitute for human urine to simulate the effects of human urine on human urine, to be used for tests of ureteral stents.3.1.2 bladder retention meansphysical
17、 feature of bladder end of stent the prevents movement of stent out of bladder.3.1.3 break strengthpeak tensile load required to break stent.3.1.4 cross sectionview of stent tube when cut in a plane perpendicular to length of stent.3.1.5 distalsituated away from the point of origin. The distal end o
18、f a stent is the end that resides in the bladder, also knownas the bladder end.3.1.6 drainage holesholes in wall of stent tubing that allow flow of urine into and out of lumen of stent.3.1.7 dynamic frictional forceresistance to relative motion between two surfaces during motion. This force is defin
19、ed as thecoefficient of kinetic friction multiplied by the force acting on the surface of the material in a plane perpendicular to the surface.3.1.8 elongationexpressed as a percent, is equal to the change in length of a sample of tubing at failure divided by its originallength. Stretching of the tu
20、bing is produced by tensile loading.3.1.9 French sizeScalescale used to indicate size of tubular devices, each unit being approximately equal to 0.013 in. or 0.33mm in diameter. Typical label French sizes are as follows:French Size Outside Diameterin. mm3.7 0.050,1.234.5 0.060,1.504.7 0.061,1.576.0
21、0.079,2.007.0 0.092,2.338.0 0.105,2.678.5 0.112,2.8310.0 0.131,3.3314.0 0.183,4.663.1.10 kidney retention meansphysical feature of kidney end of stent that prevents movement of stent out of the kidney.3.1.11 lengthlength of stent is defined as the distance between the most proximal portion of the bl
22、adder retention means andthe most distal portion of the kidney retention means when the stent is laying on a flat surface with the mainshaft straight.(Seestraight (see Fig. 1 and Fig. 2).3.1.12 lumenthe channel within a tube.3.1.13 proximalsituated toward the point of origin. In the urinary tract, t
23、he kidney is considered to be the point of origin. Theproximal end of a stent is the end that resides in the renal pelvis, also known as the kidney end.3.1.14 radiopacityproperty indicating ability of device to absorb x-ray energy, allowing device to be seen in a radiograph orfluoroscopic screen.ima
24、ge.3.1.15 referee test methodthe method cited in the published specification for the device. This method will be used when theperformance of the ureteral stent is to be evaluated. The manufacturer need not use this referee test method for inspection andquality control.3.1.16 retention strengthforce
25、required to overcome the retaining means on a stent.FIG. 1 DetermineDetermination of Stent LengthF1828 1723.1.17 sterilitythe state of being free of microorganisms. For purposes of this specification, sterility is defined as freedom frommicroorganisms when tested according to the methodology defined
26、 by the USP for nonparenteral devices.3.1.18 tolerancesthe allowable deviation from a standard size. The tolerance for the length of a ureteral stent is 60.5 cm(0.197 in). theThe tolerance for the specified French size of a ureteral stent is 60.01 mm (0.004 in), or approximately 13 French.3.1.19 ure
27、teral stentan indwelling tubular device that resides in the kidney, ureter, and bladder containing means for retainingends of tube in kidney and bladder.4. Requirements4.1 Biocompatibility Ureteral stents shall be tested in accordance with the appropriate biological tests contained inSpecification F
28、748 or similar guidance established by the U. S. Food and Drug Administration or International Organization forStandardization (ISO).5. Special Precautions5.1 The following cautionary comments recognize the sensitivity of the materials of construction to potential environmentalconditions. These are
29、outlined here to point out potential situations that could adversely affect the performance of the stent duringtesting.5.1.1 Care should be taken during testing and use to prevent damage to the stents. Such damage can be caused by abrasion andcontact with sharp objects or chemical products.5.1.2 Ste
30、nts should be kept away from generators, electric motors, diathermy machines, and fluorescent lights because the ozoneproduced may attack elastomeric materials. This applies to both storage and handling.5.1.3 To help avoid contamination of the stents proper handling precautions should be observed.6.
31、 Test Methods6.1 General Guidelines:6.1.1 Test samples should consist of actual ureteral stents, not material slabs.6.1.2 Use statistically valid sample sizes in all tests.6.1.3 Package all stent test samples and sterilize once using the method of sterilization intended to be used for product whenit
32、 is sold.6.1.4 Expose test samples to artificialhuman urine at 37 6 3 C 3C for a period of 30 days. Use either of the two artificial urineformulations listed in Annex A1. In situations where testing in artificial urine is not practical, distilled water may be used.6.1.5 Maintain artificialhuman urin
33、e pH in the range of 5.5 to 6.5 at all times. Replace human urine should be weekly.6.1.6 Perform tests prior to and after soaking for a minimum of 30 days. For products with intended chemical/mechanicalchanges such as softening, swelling, etc., doconduct initial mechanical testing only after suffici
34、ent soaking time has elapsed thatallow such chemical/mechanical changes to occur.6.1.7 Dynamic frictional force test samples need only be soaked in distilled water saline test media for 1 min prior to testing.This test will not be repeated after 30 days.6.2 Retention Strength:6.2.1 ScopeThis test me
35、thod measuredmeasures the ability of a ureteral stent to resist migration. It can be used for testing theproximal or distal ends of a ureteral stent.6.2.2 Summary of Test Method:6.2.2.1 The apparatus is set up as shown in Fig. 23. Clearance between the outside diameter of the stent and inside diamet
36、erof the funnel block hole must be present. (See Note 1 in Fig. 23 for a list of appropriate funnel block hole diameters to be usedwith stents of different French sizes.)6.2.2.2 Maintain temperature in the water bath saline test media at 37 6 3C by whatever means is available to the test facility.Su
37、bmerge the entire funnel block. Set the pull rate through the fixture at a constant 20 in.(mm)/min. in./min or 508 mm/min. Cleanthe test bath and fixture at the beginning of each testing day. The capacity of the load cell used with the tensile testing machineshould not exceed 2 lb.6.2.3 Test Specime
38、n PreparationThe test specimen shall consist of actual sterilized product. The specimen shall be cut toallow a straight portion of the stent to be inserted upwards through the funnel fixture into the grip of the tensile test machinewithout loading the retention mechanism of the stent to be tested. S
39、ubmerge the test specimen in the water bath saline test mediaFIG. 2 Determination of Stent Length (alternative stent anchorage design)F1828 173for at least 1 min to allow it to reach thermal equilibrium. If the material is significantly affected by moisture, allow the specimento equilibrate for a mi
40、nimum of 24 h. Use distilled water, if possible.NOTE 1The portion of the stent held within the gripping mechanism of the tensile testing machine cannot be used for additional testing due to thepotential destructive effects of the gripping mechanism.6.2.4 Test Procedure:6.2.4.1 Ensure test bathmedia
41、is at proper temperature and funnel is submerged. Monitor periodically.6.2.4.2 When testing a new ureteral stent taken out of its sterile package, (t=0), straighten retention means with appropriateguidewire. Insert straight portion of stent through bottom of funnel and into grip. When testing at t=3
42、0 days, retention means isnot to be straightened prior to testing.6.2.4.3 Allow stent to reach thermal equilibrium.6.2.4.4 Pull specimen up through funnel at 20 in./min. Record maximum force required to pull stent completely through funnel.6.3 Break Strength:6.3.1 Break strengths of test stents will
43、 be determined in accordance with Test Method D412, with the following modifications:6.3.1.1 Devices used to grip the test specimen in the tensile test machine should be chosen so that the test specimen does notbreak at the grip location.6.3.1.2 Most stents contain drainage holes. Ideally, these ste
44、nts should break at a drainage hole. This is how tensile failurestypically occur in vivo. However, stents may break in locations other than drainage holes. This type of failure may be indicativeof potential design or process related problems. In stents without drainage holes, this type of failure is
45、 to be expected.6.3.1.3 Only a segment of the test stent is used for the break strength test. The grippers should be separated by 1 in. This 1 in.segment must contain at least one drainage hole (if drainage holes are present) and should contain the section of the stent with thesmallest cross section
46、al area or weakest point.6.4 ElongationThe elongation of stent segments separated by 1 in. between the extensometer grips used to hold the segmentin the tensile test machine or two marks placed on the surface of the stent will be determined in accordance withTest Method D412.6.5 Dynamic Frictional F
47、orce(Required for Support of Claims of Low Friction):6.5.1 ScopeThis test method measures the dynamic frictional force acting upon the outer surface of ureteral stent duringplacement through a small orifice. This test method is intended to simulate passage of a 6 Fr ureteral stent through an endosco
48、pe.FIG. 23 Funnel Block for Retention Strength TestF1828 1746.5.2 Summary of Test MethodStraighten the test stent using a wire mandrel and hydrated in a cylinder of distilled water.saline test media. Then place it completely through the appropriate size grommet and into a water column. The mandrel i
49、sconnected to a load cell that is pulled at constant rate of 20 in/min. Record the force values measured by the load cell on a chartrecorder or minicomputercomputer and average to determine the dynamic frictional force.6.5.3 Test Set-Up(See Fig. 34.)6.5.3.1 CylinderCylinder, capable of hydrating the full length of the ureteral stent sample.6.5.3.2 Water ColumnColumn, used to hydrate the full length of the test stent prior to passage through grommet.6.5.3.3 Distilled WaterSaline Test Media, used to hydrate the test stent (and activate any
