Magnetically-Controlled Growing Rods

Growing Rods

As
mentioned in earlier blogs, nonsurgical management of early-onset scoliosis
(EOS), which can consist of bracing, casting, observation, and physical therapy
is usually the primary treatment, especially for mild/moderate curve with no or
mild progression.  Surgery for EOS is
reserved for patients whose deformities are severe and/or progressive, and
cannot be or have not been successfully treated with those nonsurgical
methods.  The surgeon will evaluate the
child’s spinal deformity, age, physical size, medical condition, and other
factors when determining the need for surgery.
One
of mainstays in the surgical treatment of infantile/juvenile/early-onset
scoliosis (EOS) has been Growing Rods.
These rods do not actually grow, like the child, but can be lengthened
or “distracted” in the operating room on a routine interval, to straighten the
spine.  This is much like jacking up a
car to change a tire, the jack is the Growing Rod.  One difference is the jack/Growing Rod is
implanted in the child’s back so it works 24/7 attempting to correct and
maintain the child’s scoliosis in a straightened position.
There
is a large volume of information published on Growing Rods, with the one of
first major publications on their use in children in 20 years ago, by Klemme et
al.  Since that time, Growing Rods have
become the most common surgical treatment for EOS.  If one searches for “growing rods scoliosis”
on PUBMED, the U.S. National Library of Medicine/NIH website for medical
journal publication, there will be over 150 articles published in peer-reviewed
journals.  There are many reasons for the
acceptance of Growing Rods as the “gold standard” for the surgical treatment of
EOS: abundant literature supporting their effectiveness, ease of use by surgeons,
and the surgeries are well-tolerated by patient in terms of pain, function and
outcomes. 
As
mentioned above the Growing Rods achieve straightening of the spine by creating
lengthening of the rods via a connector between two segments of rods.  So in actuality, as shown in the above
radiographs, there are actually 4 segments of rods, two on each side with a
connector between them.  The attachment sites
of the Growing Rods to create the straightening effect can be on the spine, ribs
or the pelvis, which are done with screws or hooks.  The nice thing about Growing Rods is that
they are very utilitarian, because they can attach at a variety of places with
several different types of bone anchors.
This is very helpful since each child’s spine deformity is unique and each
can create challenges to safely treat.
 

This
patient had fixation with screws at the bottom and the use of hooks onto 4 ribs
on each side.

Prior
to recent advances in EOS treatment with the MAGEC device, one of the less
attractive aspects of Growing Rods is the need for operative lengthening.  These small surgeries are typically every 6
months, but like any other surgery on children requires the use of general
anesthesia.  In addition in order to
lengthen Growing Rods the surgeons needs to incise the skin, expose part of the
spine construct and then lengthen or distract the construct.  The major concern with the creation of
incisions is the risk for infections, both of the skin and also of the
metal.  If a deep infection of the
implants occurs, the metal typically needs to be removed and the infection
treated with intravenous antibiotics. 

Once
the Growing Rods have been implanted they are lengthened in the operating room
about every 6 months.  This is usually continued
until the child is at or near the end of their growth.  At that time the Growing Rods can be removed
and converted to a definitive posterior spinal fusion, which would be the last
planned surgery for the spine deformity.

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