Bring Testing In-House
X-spine Systems Inc. (Dayton, OH) conceives, designs and manufactures advanced spinal implant products, including titanium and Invibio Peek Optima biocompatible polymer structures. The company also manufactures complementary spinal instrumentation designed to maximize surgical access and visualization, while minimizing tissue disruption.
X-spine is FDA registered and ISO 13485 compliant. It performs biomechanical testing on all of its components to ASTM F1717 or F1798 standards or both, as well as other industry-standard physiological load performance measures. The extensive testing regimen supports both development and manufacturing.
“We conduct biomechanical testing for both quality control and product development, looking for peak load, yield, yield load, percent of elongation and elasticity,” says David Kirschman, X-spine president.
Each material has its own characteristics. The Invibio Peek Optima polymers have a modulus of elasticity that is similar to bone, while the titanium materials and structures are tested to much higher peak loads. All compression and tension tests are to failure.
The company also tests its Capless LI pedicle screws by securing them to a polyurethane foam block and finding the force required to pull the screw out. A cantilever pushdown test measures the force required to bend the screw.
Initially, X-spine outsourced all of its biomechanical testing. As production ramped up, however, it became cumbersome and inefficient to rely on outside services, particularly for ad hoc testing. Kirschman decided to bring some testing in-house.
X-spine searched the Internet for a solution. “At the time we wanted a simple machine that we could use to do some basic biomechanical testing,” says Kirschman. “It seemed like screw-based machines, rather than servohydraulic machines, economically served this need.”
Selecting a Universal TesterAfter determining that electromechanical screw-based machines were appropriate for its needs, X-spine looked at a number of different brands online. The company selected the Admet (Norwood, MA) eXpert 5601 tabletop machine with an eP controller, 1.1-kilonewton load cell and WinCOM Plus data communications program.
The eXpert 560x line of universal testing machines from Admet performs low-force tension, compression and bend tests from less than 1 pound to 1,400 pounds, or 6.2 kilonewtons. Some models are capable of speeds in excess of 200 inches per minute, or 5,000 millimeters per minute, and can be used in high-speed dynamic testing.
Ad Hoc and Sample TestingX-spine employs the eXpert as a standalone unit primarily used by engineers and technicians for ad hoc and sample testing. Parts are tested from every lot.
Test data are generally viewed on the eP controller readout for quality control verification purposes. On some occasions, the data are filed in internal reports or used for sales literature.
The eXpert machine has served X-spine’s ad hoc testing needs well, and setup is simple and quick.
“The nice thing about the Admet is it is a very simple machine with the computer/controller built in,” says Kirschman. “A quality control inspector can come in and operate it efficiently and easily to run an individual part for a static test.”
In addition to the eXpert, X-spine uses other servohydraulic testing machines for fatigue and cyclic testing. The company continues to complement its in-house testing program with outside testing labs, particularly for FDA-mandated testing batteries and validation of in-house results.