Wednesday, February 1, 2017

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.