1、Designation: 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 in parentheses indicates
2、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 stent, having retention mean
3、s 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 construed as productionmeth
4、ods, 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 forevaluating the performance character
5、istics of a single-useureteral stent with retaining means at both ends, during shortterm use for drainage of urine from the kidney to the bladder.These stents are typically available in diameters of 3.7 Fr to14.0 Fr, and lengths of 8 cm to 30 cm, and are made of silicone,polyurethane, and other poly
6、mers. 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 of ureteral stents for non-uret
7、eral applica-tions such as nephrostomy and ileostomy is excluded from thescope of this specification. Non-sterile ureteral stents are alsoexcluded due to the variability of hospital sterilization equip-ment and processes and the resulting effects on ureteral stentcharacteristics.1.3 The following pr
8、ecautionary statement pertains only tothe test method portion, Section 5, of this specification:1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health p
9、ractices and determine the applica-bility of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides
10、 and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionF640 Test Methods for Determining Radiopacity for Medi-cal UseF748 Practice f
11、or Selecting Generic Biological Test Methodsfor Materials and Devices3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 test media (1) saline, an isotonic solution of pH 5.5to 7.0; or (2) human urine, to be used for tests of ureteral stents.3.1.2 bladder retention meansphysical f
12、eature of bladderend of stent the prevents movement of stent out of bladder.3.1.3 break strengthpeak tensile load required to breakstent.3.1.4 cross sectionview of stent tube when cut in a planeperpendicular to length of stent.1This specification is under the jurisdiction of ASTM Committee F04 onMed
13、ical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.34 on Urological Materials and Devices.Current edition approved March 1, 2017. Published April 2017. Originallyapproved in 1997. Last previous edition approved in 2014 as F1828 97 (2014).DOI: 10.1520/F1828-17
14、.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box
15、C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the
16、 World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.5 distalsituated away from the point of origin. Thedistal end of a stent is the end that resides in the bladder, alsoknown as the bladder end.3.1.6 drainage holesholes in wall of stent tubing thatallow flow of urine into and
17、out of lumen of stent.3.1.7 dynamic frictional forceresistance to relative motionbetween two surfaces during motion. This force is defined asthe coefficient of kinetic friction multiplied by the force actingon the surface of the material in a plane perpendicular to thesurface.3.1.8 elongationexpress
18、ed as a percent, is equal to thechange in length of a sample of tubing at failure divided by itsoriginal length. Stretching of the tubing is produced by tensileloading.3.1.9 French sizescale used to indicate size of tubulardevices, each unit being approximately equal to 0.013 in. or0.33 mm in diamet
19、er. 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 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 kidneyend of stent that prevents movement o
20、f stent out of the kidney.3.1.11 lengthdistance between the most proximal portionof the bladder retention means and the most distal portion ofthe kidney retention means when the stent is laying on a flatsurface with the mainshaft straight (see Fig. 1 and Fig. 2).3.1.12 lumenchannel within a tube.3.1
21、.13 proximalsituated toward the point of origin. In theurinary tract, the kidney is considered to be the point of origin.The proximal end of a stent is the end that resides in the renalpelvis, also known as the kidney end.3.1.14 radiopacityproperty indicating ability of device toabsorb x-ray energy,
22、 allowing device to be seen in a radiographor fluoroscopic image.3.1.15 referee test methodmethod cited in the publishedspecification for the device. This method will be used when theperformance of the ureteral stent is to be evaluated. Themanufacturer need not use this referee test method for inspe
23、c-tion and quality control.3.1.16 retention strengthforce required to overcome theretaining means on a stent.3.1.17 sterilitystate of being free of microorganisms. Forpurposes of this specification, sterility is defined as freedomfrom microorganisms when tested according to the methodol-ogy defined
24、by the USP for nonparenteral devices.3.1.18 tolerancesallowable deviation from a standardsize. The tolerance for the length of a ureteral stent is 60.5 cm(0.197 in). The tolerance for the specified French size of aureteral stent is 60.01 mm (0.004 in), or approximately13French.3.1.19 ureteral stenti
25、ndwelling tubular device that residesin the kidney, ureter, and bladder containing means for retain-ing ends of tube in kidney and bladder.4. Requirements4.1 Biocompatibility Ureteral stents shall be tested inaccordance with the appropriate biological tests contained inSpecification F748 or similar
26、guidance established by the U. S.Food and Drug Administration or International Organizationfor Standardization (ISO).5. Special Precautions5.1 The following cautionary comments recognize the sen-sitivity of the materials of construction to potential environ-mental conditions. These are outlined here
27、 to point out poten-tial situations that could adversely affect the performance of thestent during testing.5.1.1 Care should be taken during testing and use to preventdamage to the stents. Such damage can be caused by abrasionand contact with sharp objects or chemical products.FIG. 1 Determination o
28、f Stent LengthF1828 1725.1.2 Stents should be kept away from generators, electricmotors, diathermy machines, and fluorescent lights because theozone produced may attack elastomeric materials. This appliesto both storage and handling.5.1.3 To help avoid contamination of the stents properhandling prec
29、autions should be observed.6. 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 usingthe method of sterilization intended to
30、 be used for productwhen it is sold.6.1.4 Expose test samples to human urine at 37 6 3C for aperiod of 30 days.6.1.5 Maintain human urine pH in the range of 5.5 to 6.5 atall times. Replace human urine weekly.6.1.6 Perform tests prior to and after soaking for a minimumof 30 days. For products with in
31、tended chemical/mechanicalchanges such as softening, swelling, etc., conduct initialmechanical testing only after sufficient soaking time haselapsed that allow such chemical/mechanical changes to occur.6.1.7 Dynamic frictional force test samples need only besoaked in saline test media for 1 min prio
32、r to testing. This testwill not be repeated after 30 days.6.2 Retention Strength:6.2.1 ScopeThis test method measures the ability of aureteral 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 se
33、t up as shown in Fig. 3. Clearancebetween the outside diameter of the stent and inside diameterof the funnel block hole must be present. (See Note 1 in Fig. 3for a list of appropriate funnel block hole diameters to be usedwith stents of different French sizes.)FIG. 2 Determination of Stent Length (a
34、lternative stent anchorage design)FIG. 3 Funnel Block for Retention Strength TestF1828 1736.2.2.2 Maintain temperature in the saline test media at 376 3C by whatever means is available to the test facility.Submerge the entire funnel block. Set the pull rate through thefixture at a constant 20 in./mi
35、n or 508 mm/min. Clean the testbath and fixture at the beginning of each testing day. Thecapacity of the load cell used with the tensile testing machineshould not exceed 2 lb.6.2.3 Test Specimen PreparationThe test specimen shallconsist of actual sterilized product. The specimen shall be cutto allow
36、 a straight portion of the stent to be inserted upwardsthrough the funnel fixture into the grip of the tensile testmachine without loading the retention mechanism of the stentto be tested. Submerge the test specimen in the saline testmedia for at least 1 min to allow it to reach thermal equilib-rium
37、. If the material is significantly affected by moisture, allowthe specimen to equilibrate for a minimum of 24 h.NOTE 1The portion of the stent held within the gripping mechanismof the tensile testing machine cannot be used for additional testing due tothe potential destructive effects of the grippin
38、g mechanism.6.2.4 Test Procedure:6.2.4.1 Ensure test media is at proper temperature andfunnel is submerged. Monitor periodically.6.2.4.2 When testing a new ureteral stent taken out of itssterile package, (t=0), straighten retention means with appro-priate guidewire. Insert straight portion of stent
39、through bottomof funnel and into grip. When testing at t=30 days, retentionmeans is not 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 completelythrough funnel.6.3
40、Break Strength:6.3.1 Break strengths of test stents will be determined inaccordance with Test Method D412, with the following modi-fications:6.3.1.1 Devices used to grip the test specimen in the tensiletest machine should be chosen so that the test specimen doesnot break at the grip location.6.3.1.2
41、 Most stents contain drainage holes. Ideally, thesestents should break at a drainage hole. This is how tensilefailures typically occur in vivo. However, stents may break inlocations other than drainage holes. This type of failure may beindicative of potential design or process related problems. Inst
42、ents without drainage holes, this type of failure is to beexpected.6.3.1.3 Only a segment of the test stent is used for the breakstrength test. The grippers should be separated by 1 in. This 1in. segment must contain at least one drainage hole (if drainageholes are present) and should contain the se
43、ction of the stentwith the smallest cross sectional area or weakest point.6.4 ElongationThe elongation of stent segments separatedby 1 in. between the extensometer grips used to hold thesegment in the tensile test machine or two marks placed on thesurface of the stent will be determined in accordanc
44、e with TestMethod D412.6.5 Dynamic Frictional Force(Required for Support ofClaims of Low Friction):6.5.1 ScopeThis test method measures the dynamic fric-tional force acting upon the outer surface of ureteral stentduring placement through a small orifice. This test method isintended to simulate passa
45、ge ofa6Frureteral stent through anendoscope.6.5.2 Summary of Test MethodStraighten the test stentusing a wire mandrel and hydrated in a cylinder of saline testmedia. Then place it completely through the appropriate sizegrommet and into a water column. The mandrel is connected toa load cell that is p
46、ulled at constant rate of 20 in/min. Recordthe force values measured by the load cell on a chart recorderor computer and average to determine the dynamic frictionalforce.6.5.3 Test Set-Up(See Fig. 4.)6.5.3.1 Cylinder, capable of hydrating the full length of theureteral stent sample.6.5.3.2 Water Col
47、umn, used to hydrate the full length of thetest stent prior to passage through grommet.6.5.3.3 Saline Test Media, used to hydrate the test stent (andactivate any hydrophilic coating present) at room temperature.6.5.3.4 Grommet0.040 6 0.002 in. thick, 5/8 in. diameterdisc, with a 0.079 6 0.002 in. di
48、ameter hole in the center. Thegrommet is to be made of 55 Shore A Durometer silicone.6.5.3.5 Grommet FixtureThe grommet is held in place bytwo aluminum plates containing relief holes approximately18in. larger is diameter than the hole in the grommet. Whenmounted, the hole in the grommet should be ce
49、ntered about therelief hole in the aluminum plates.6.5.3.6 Load CellLoad cell capacity should not exceed 1lb, and should be capable of measuring the frictional forcewithin 65 % of its value.6.5.3.7 Linear Table, used to pull the load cell at a constantrate. A linear table will not be necessary if a standard tensiletest machine is used.6.5.3.8 Mandrel, large enough to straighten and hold the teststent during the test. An eyelet is used on one end to attach tothe load cell.6.5.4 Precautions:6.5.4.1 Follow all proper safety precauti
