ASTM F2392-04
(Test Method)Standard Test Method for Burst Strength of Surgical Sealants
Standard Test Method for Burst Strength of Surgical Sealants
SIGNIFICANCE AND USE
Materials and devices that function at least in part by adhering to living tissues are finding increasing use in surgical procedures, either as adjuncts to sutures and staples or as frank replacements for those devices in a wide variety of medical procedures. While the nature and magnitude of the forces involved varies greatly with indication and with patient specific circumstances, all uses involve, to some extent, the ability of the material to resist imposed mechanical forces. Therefore, the mechanical properties of the materials, and in particular the adhesive and cohesive properties, are important parameters in evaluating their fitness for use. In addition, the mechanical properties of a given sealant composition can provide a useful means of determining product consistency for quality control, or as a means for determining the effects of various surface treatments on the substrate prior to use of the device.
The complexity and variety of individual applications for sealant, even within a single indicated use (surgical procedure), is such that the results of a burst test are not suitable for determining allowable design stresses without thorough analysis and understanding of the application and sealant behaviors.
This test method may be used for comparing sealants for susceptibility to environmental changes, but such comparisons must be made with great caution since different sealants may respond differently to varying conditions.
As the true sealant strength is strongly dependent on the strength of the sealant/substrate interface, the selection of a proper test substrate is critical. Care must be taken when extrapolating in vitro test results to in vivo expectations. In vitro sealant optimization may not translate to expected in vivo performance due to differences in substrate surface, strength, and elasticity.
SCOPE
1.1 This test method provides a means for comparison of the burst or rupture strength of sealants on soft tissue. This test method can be used as a clinically relevant model for quality assurance, development, and comparative testing of different adhesives or adherends.
1.2 This test method measures only burst strength or "cohesive strength" of an adhesive/adherend system, and not the adhesive strength.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation:F2392–04
Standard Test Method for
Burst Strength of Surgical Sealants
This standard is issued under the fixed designation F2392; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2.3 cohesive failure—failure of the sealant during burst
testing.
1.1 Thistestmethodprovidesameansforcomparisonofthe
3.2.4 cohesive strength—the internal strength of the sealant,
burst or rupture strength of sealants on soft tissue. This test
sometimes referred to as the adhesive bulk strength.
method can be used as a clinically relevant model for quality
3.2.5 substrate failure—failure of the substrate during burst
assurance, development, and comparative testing of different
testing.
adhesives or adherends.
3.2.6 tissue sealant—asurfacecoatingtopreventleakageof
1.2 This test method measures only burst strength or “co-
body fluids.
hesive strength” of an adhesive/adherend system, and not the
adhesive strength.
4. Significance and Use
1.3 This standard does not purport to address all of the
4.1 Materials and devices that function at least in part by
safety concerns, if any, associated with its use. It is the
adhering to living tissues are finding increasing use in surgical
responsibility of the user of this standard to establish appro-
procedures, either as adjuncts to sutures and staples or as frank
priate safety and health practices and determine the applica-
replacements for those devices in a wide variety of medical
bility of regulatory limitations prior to use.
procedures. While the nature and magnitude of the forces
2. Referenced Documents involvedvariesgreatlywithindicationandwithpatientspecific
circumstances, all uses involve, to some extent, the ability of
2.1 ASTM Standards:
thematerialtoresistimposedmechanicalforces.Therefore,the
D907 Terminology of Adhesives
mechanical properties of the materials, and in particular the
2.2 American Association for Tissue Banks (AATB) Stan-
adhesive and cohesive properties, are important parameters in
dard:
evaluating their fitness for use. In addition, the mechanical
Standards for Tissue Banking
properties of a given sealant composition can provide a useful
3. Terminology
means of determining product consistency for quality control,
or as a means for determining the effects of various surface
3.1 Definitions—Many terms in this test method are defined
treatments on the substrate prior to use of the device.
in Terminology D907.
4.2 The complexity and variety of individual applications
3.2 Definitions:
for sealant, even within a single indicated use (surgical
3.2.1 adhesive failure—failure of the sealant/substrate inter-
procedure), is such that the results of a burst test are not
face during burst testing.
suitable for determining allowable design stresses without
3.2.2 burst strength—the average pressure required to cause
thorough analysis and understanding of the application and
failure of the sealant, either by cohesive or adhesive mecha-
sealant behaviors.
nisms.
4.3 Thistestmethodmaybeusedforcomparingsealantsfor
susceptibility to environmental changes, but such comparisons
must be made with great caution since different sealants may
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
respond differently to varying conditions.
F04.15 on Material Test Methods.
4.4 As the true sealant strength is strongly dependent on the
Current edition approved May 1, 2004. Published June 2004. DOI: 10.1520/
strength of the sealant/substrate interface, the selection of a
F2392-04.
proper test substrate is critical. Care must be taken when
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
extrapolating in vitro test results to in vivo expectations. In
Standards volume information, refer to the standard’s Document Summary page on
vitro sealant optimization may not translate to expected in vivo
the ASTM website.
performance due to differences in substrate surface, strength,
Available from American Association for Tissue Banks (AATB), 1320 Old
Chain Bridge Rd., Suite 450, McLean, VA 22101. and elasticity.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2392–04
5. Apparatus pumps are particularly well suited for this type of testing since
they do not cause pulsatile flow. Peristaltic pumps have also
5.1 Testing Machine—A testing machine for determining
been used successfully since the pump tubing tends to dampen
the sealant strength and system failure mechanism and com-
pulsations.
prising essentially the following:
5.1.1 Test Fixture—A stationary fixture containing the test
NOTE 1—Saline is the typical fluid of choice. When air is used, a
substrate and applied sealant. Fluid flows into the fixture at a
reduction in pressurization rate is expected due to gas compressibility.
fixed rate, allowing for the pressurization of the sealed sub-
5.1.3 Pressure gage—Consisting of a gage and method of
strate.
capturing peak pressures. System sampling rate should be
5.1.2 Positive Displacement Fluid Pump—A pump provid-
adequate to capture peak burst pressures. Sensitivity and
ing a constant flow of fluid to the test fixture. The pump must
be capable of constant flow at pressures of interest. Syringe precision should result in less than 1 % error. The burst test
FIG. 1 Burst Test System (A), with an Exploded View of the Assembled Test Fixture (B),
and the Test Fixture Cross Sectional View (in.) (C)
F2392–04
system is shown in Fig. 1. The system (A) consists of a fluid lead to unacceptable variation in the test results, especially if
pump, a test fixture, and pressure gage connected by rigid the failure occurs in the adherend (substrate failure). Since the
plastic tubing. The test fixture (B) consists of a base, O-ring, purpose of quality control testing is to demonstrate consistency
and top. in the device, substitution of a model substrate is preferred so
5.2 Temperature-controlling Equipment—Must be capable long as it is demonstrated that the sealant does bond to the
of maintaining the test temperature to 62°C. If ambient adherend.Sincethebursttestfailuremechanismcandependon
laboratory conditions are employed, the same degree of control the amount of substrate deformation, attention to substrate
is required.Awater bath or environmental chamber capable of flexibility and elasticity is important to best match in vivo
maintaining 37°C is required for testing on tissue substrates. substrates.
6. Test Substrate 7. Substrate Preparation
6.1 For Comparative Testing—Collagen sausage casing, 7.1 Cut substrate into circles (3.0 6 0.1 cm diameter) using
Nippi Casing Co. (#320), should be used. It is a collagen a sharp scalpel or stamp.
7.2 Useaholepunchtocreatea3.0mmdiameterholeinthe
casing of consistent properties and thickness.
6.2 Cut sections off of the collagen casing roll, wash in center of the circular substrate.
deionized water (to remove glycerin), then soak in fresh
NOTE 2—Depending on the application, different hole sizes, cuts, or
deionized water for five minutes.
suture lines may be used. Store in saline at room temperature until ready
6.3 Application Specific Testing—Since the fixture must
to use if testing will be done within1hof preparation. Prepared substrate
clamp down on the substrate to prevent fluid leakage, some may be stored in saline in a refrigerator for up to 48 h.
tissues (lung, liver, and so forth) may not be suitable for this
7.3 Number of Test Specimens—Test at least 10 specimens
test.
ofeachtype.Bursttestingtendstogivehighvariancesandwill
6.3.1 The burst strength of any sealant is dependant on its
require more samples to attain a reasonable estimate of the
internal cohesive strength, as well as the adhesive stren
...
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