Testing Talk

ASTM F1798 describes the procedure for testing subassemblies and interconnection mechanisms to determine the fatigue strength and resistance to loosening during arthrodesis.(fusion)

Hooks, screws, and bands connect to rods and plates. These connected parts form Spinal Implant Subassemblies. In this specification the parts are tested in a saline or simulated body fluid in vitro to predict the behavior of the parts in vivo performance.

Tapers are used in modular devices, like shoulder and hip prothesis. This method assesses the axial locking forces of these tapers. Full description of ASTM F2009 can be found at www.astm.org. The ADMET eXpert 2600 will perform the Constant Rate Assembly and Disassembly Procedure and provide the appropriate fixtures needed to secure the tapers during testing.

ASTM F2258 describes the testing procedure to obtain data to compare adhesive strengths of tissue adhesives intended for use as surgical adhesives or sealants, or both on soft tissue. 

Preparing the Test Substrate is a critical part of this specification. 

These tests allow the user to compare the mechanical properties of artificial discs intended for different locations (Cervical, Thoracic, and Lumbar). This is a summary of the specification ASTM F2346, please read the full specification for details. 

The Static testing simulates a motion segment by measuring the gap between two stainless steel blocks. (min yield 1170MPa)

The Fatigue testing simulates motion segment by measuring the gap between two polyacetal blocks. (min tensile strength 61MPa)

ASTM F2193 encompasses varied test annexes to perform determining the strength, stiffness, and durability of spinal screws.

ADMET’s  eXpert 2600 will perfom the following tests:

ASTM F2502 is a standard for testing Bioabsorbable Plates and Screws for Internal Fixation Implants.

These types of plates and screws are resorbed into the body once implanted to unstable bone or tissue connected to bone. The advantage over a metallic fixation device is that a bioabsorbable device does not need to be removed. The challenge to medical device manufacturers of bioabsorbable devices is to ensure full healing takes place before the bioabsorbable device is fully deteriorated.

There are four Annexes describing the testing procedures to follow in this specification.

Spinal Implants and Intervertebral Fusion Devices are tested according to several ASTM standards. ASTM F2267 is intended to provide a basis for the mechanical comparison among past, present and future non-biologic intervertebral body fusion devices. These, sometimes hollow, devices are inserted to promote arthrodesis(fusion) at a given spinal motion segment. Construct are governed by ASTM F1717.

Shear joints impose uniform stresses across the bond area which results in the highest possible joint strength. ASTM D1002 is commonly performed to measure the shear strength of adhesives that are used to bond metals. This test is similar to ASTM D3163 which is for adhesives that bond rigid plastic substrates, and also ASTM D3164 which is for plastic adhesives that are used to bond both plastic and metal substrates. All three of these specifications use a single lap joint (lap shear) specimen to

determine the shear strength of adhesives. If you are going to perform this test, you should read the entire specification from ASTM.

In the ASTM acceptance standard for testing rubber surgical gloves (D3577) and rubber medical gloves (D3578), made of latex, vinyl, and nitrile. The standard describes the standard size, material properties, physical and mechanical property acceptance levels, aqueous protein and antigen protein content, and visual inspection required for a glove to be used in a medical procedure. Other relevant standards include ASTM D6319, ASTM D5250, EN 455-2, ISO 11193-1:2002, and ISO/AWI 11193-2.