Magnetically-Controlled Growing Rods

MAGEC (Part 3)

Follow-up on the reported complications of the MAGEC
In the last blog post three modes of failure of this device
were described: rod breakage, actuator pin breakage (inside the device) and rod
breakage.  It should be noted that with
traditional growing rods, breakage of the rods is a common occurrence, so this
problem is due to rigid rods taking the stress from a flexible child’s spine.
Remember, all metals gradually fatigued over time as they are stressed by
bending and twisting.  The smaller the
diameter the rod the greater the chance of it breaking.
As mentioned in the previous blog the actuator pin, which is
inside the device, has been re-engineered to be stronger.  Children who had their MAGEC devices
implanted after the FDA clearance of this device have the improved, stronger
MAGEC device design.
What are the outcomes of this new device?  Better, worse or the same?
Research in Early-Onset Scoliosis (EOS), like many areas of
medicine, is very hard to complete.  For
one thing it is a relatively uncommon problem in our population.  EOS also encompasses a wide variety of
diagnoses, deformities types and severity.
The combination of being uncommon and highly variable patient to patient
makes research challenging.  As such, it
can be difficult for one surgeon or even one hospital to have enough patients
to study a particular problem or treatment.
This is why many published research studies on EOS are from surgeon study
groups, which are research collaborations between institutions around the
world.  This permits surgeons to pool
their data, unidentified to protect the patient, with other surgeons from
around the world in order to get enough patients to study a research
Since the MAGEC device has only been approved in the U.S.
since 2014, the longest study follow-up in the U.S. is only a couple of years,
too short to really help us at all.  The
longer follow-up studies, which are really only intermediate length, are from
Europe and Asia.  There are no
comparative, long-term studies (>7 years) on the MAGEC device.  So we have to rely on short-term and
intermediate-term studies on this device.
Most of the studies published and presented on MAGEC growing
rods have reported similar radiographic outcomes when compared to traditional
growing rods (TGR).  Correction of the
spinal deformity and providing vertical growth of the chest appear to be
overall similar.  However, there are many
questions about the device longer-term such as:
Will actuator failure frequency increase the
longer the device is implanted?
Will the spine become more rigid over time like is
seen in traditional growing rods? 
Is the MAGEC device cost-effective in it real
world applications?  Each actuator costs
as much as a new compact automobile, and typically two of these are implanted
in each child.
How much should the MAGEC device be lengthened
at each office visit and how often should the device be lengthened? 
Are the indications for the use of MAGEC devices
the same as for TGRs?
We have many unanswered questions about the device, however
the device appears to have more positive aspects than negative.
Is the surgery to place a MAGEC growing rod different
than traditional growing rods (TGR)?
The surgical approach is the same for both procedures, but
the big difference is the MAGEC rods are one long rod whereas each TGR is
actually two short rods connected together.
So the MAGEC rods are much more difficult to place in a child,
especially when the child is short, is thin and has a large spinal
deformity.  The MAGEC devices need
between 9 and 11 centimeters of relatively straight spine to place the MAGEC
rod without it being too prominent under the skin.  Optimal placement of this device requires a
high level of surgical skill with strong spine (pedicle screws) or pelvic
fixation points.
How do I find a surgeon who uses MAGEC devices?
It is important to pick a surgeon who frequently cares for
EOS as they can decide, based on their experience with all types of treatment
options, if MAGEC or another type of surgery is optimal.
A good way to find one of these surgeons is to go the
Growing Spine Foundation Website to find a center near you:
Our EOS spine centers at St. Louis Children’s Hospital
(314-454-2045) and Shriner’s Hospital for Children, St. Louis unit
(314-432-3600) are always willing to help.

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