Testing
MDTmag.com 36 / March 2014
By Dipl.-Ing. Andrej Mahr, Applications
Engineer, MTS Systems Corp.
There are 1.4 million trauma-related spinal injuries every year around the world1, of which 15% require surgical
intervention2. Many of these cases involve
teenagers who have their entire lives ahead
of them, making pain elimination and mobility restoration especially critical. Improving
healing time is also essential. According to a
recent study out of Ireland, traumatic spinal
injury patients require an average of 46 days
of inpatient care.
The Institute of Technology, Tallaght
(ITT Dublin) is a university-level institution located in South Dublin, Ireland. The
Research Applied –
Enhancing Healthcare
with Test Equipment
Spinal trauma has significant impacts on quality of life for patients requiring surgical treatment. Therefore,
ensuring the best technology and techniques are utilized for an improved level of care is paramount. This
article shows how MTS Systems helps biomechanical engineering students optimize two common spinal
trauma surgery procedures.
Bioengineering Technology Centre (BTC)
provides applied research within the ITT
School of Engineering, offering intensive
instruction to a handful of students pursuing
advanced degrees in biomechanical engineering. BTC strives to apply engineering
principles to medical problems, with the
goal of yielding new innovations that can be
used in clinical practice to enhance patient
quality of life.
Most recently, the BTC has focused its
applied research on optimizing
two widely used spinal surgery
procedures — spinal fracture
stabilization and balloon kyphoplasty — to help surgeons produce
the best outcomes and minimize
common post-surgery complications, both of which reduce
hospital time.
The spinal fracture stabilization procedure uses screws and
rods to mechanically stabilize
the injured portion of the spine.
Balloon kyphoplasty uses an in-
flatable balloon to restore height
for a collapsed vertebrae, fol-
lowed by bone cement injection
to stabilize the structure. Many
kyphoplasty patients fracture
adjacent areas of their spine after healing
from surgery.
Optimizing both procedures involves the
same challenges for the BTC. The research-
ers must find a way to gather meaningful
test data in a test lab environment through
the accurate replication of in-vivo loads and
moments of the human spine.
“The spine is a fascinating area of study,
because it is such a complex mechanical
system with so many unknowns,” said Colin
Bright, the postgraduate student leading the
fracture stabilization study. “Our goal was to
capture data from real-life simulations and
adapt it to a test environment in order to
reduce the unknowns with fracture stabilization and balloon kyphoplasty.”
The MTS Solution
The BTC employs an MTS Model 858 Bionix Test System with MTS Flex Test controls
and MTS MultiPurpose Test Ware software
( www.mts.com) to support its applied
research initiatives. This servohydraulic
system can precisely simulate a full range of
motions to spine specimens in six degrees of
freedom, including flexion, extension, lateral
bending, torsion, X-axis shear, and Z-axis
shear. Test load data from a six degrees of
freedom load cell and test displacement data
from angular displacement transducers are
acquired during the kinematic simulations
on the test system.
Both the fracture stabilization and balloon
kyphoplasty studies utilize porcine vertebral
specimens, which are similar in size and
structure to the human spine. The MTS
Bionix test system is first used to induce
spinal injuries that both procedures typically
treat. Next, each procedure is performed on
the specimen and then subjected to a series
of static and fatigue mechanical tests.
The ITT Dublin Bioengineering Technology Centre (BTC) Team from left to
right: Postgraduate students Bernard Lawless, Colin Bright, Philip Purcell
and Nor Amalina; supervisors Dr. Fiona McEvoy and Stephen Tiernan.
(Credit: The Institute of Technology, Tallaght)