Wednesday, March 18, 2020

The Shilla Growth Guidance Procedure

My first on this surgical technique was in August of 2018, and I posted yesterday how I compare Shilla Growth Guidance against Traditional Growing Rods and MAGEC Growing Rods.  I will continue to discuss the Shilla Growth Guidance System using a Frequently-Asked-Question format, based on questions parents and caregivers have asked me over the last 10 years.

What size of scoliosis curve can be treated with a Shilla?
The Shilla Growth Guidance System has been used in the treatment of scoliosis 40° or greater (up to 115°, typically 60-80° range).

Can Shilla be used in patients at or near skeletal maturity? 
This Growth Guidance System requires the patient have spinal growth remaining to justify the modulation or guidance of spine growth.  In general, we perform this surgery in patients where spinal growth is anticipated for at least 3 years postoperatively.  If there is less than 3 years of spine growth remaining patients will typically be better treated with a definitive spinal fusion (curves greater than 50 degrees) or other growth modulation techniques such as vertebral body tether or posterior distraction constructs (curve 40-60 degrees).

How is the amount of growth remaining estimated? 
The main factor used in this determination is radiologic evidence of the child’s “bone age”, which can be very different to their chronologic age, based on the date of birth.  Currently the main classification used for determination of “bone age” is the Sanders Classification (reference 1), which uses radiologic evaluation of the growth plates in the hand.  The other method is to judge the amount of ossification (bone development) on the top of the iliac crests (hip bone), and is called the Risser Grade.

Which scoliosis curve patterns can be treated with Shilla?
The most common curve pattern treated is the single curve patterns (thoracic or thoracolumbar), and is the easiest to manage.  Double major curves (one thoracic and one lumbar) and single lumbar curves have been treated with Shilla constructs, but there is much less clinical experience in these curve patterns.   
Thoracic curve
Double Major

Which diagnoses have been treated with Shilla? 
Diagnoses for which the Shilla has been used include: infantile and juvenile idiopathic scoliosis, congenital scoliosis, Beale’s syndrome, myelomeningocele, Marfan’s, neurofibromatosis, spinal muscular atrophy, arthrogryposis, multiple pterygium syndrome, spinal cord tumors, Prune Belly, Dandy-Walker, hypophosphatasia and dwarfism.  In general, all types of early-onset scoliosis (idiopathic, congenital, neuromuscular and syndromic) can be effectively treated by Shilla Growth Modulation System.

What is the age range for patients treated with Shilla? 
Ages at the time of surgery have ranged from 23 months to 11 years with the average patient being around 6-8 years. 

How do you decide when to do a Shilla?
Curve magnitude, documentation of curve progression, and skeletal age have been the key determinants in the decision to operate.

What is the longest follow-up at Wash U?
10 years postop

What does the prototypical construct for look like? 
If you look at the blog post from August 2018 I demonstrated a common spinal construct for Shilla.  What makes Shilla different than growing rod construct is the most curved part of the spine (called the apex) is actively straightened by using multiple pedicle screws, and then creating a solid bony fusion.  By fusing the apex of the scoliosis this most problematic part of the spine will not curve again and will remain in a straightened position.  The apex fusion is usually 2-4 vertebral levels, and the below case has 4 vertebral levels fused T8 through T11, using 8 pedicle screws.  There are 5 screws above and 5 screws below the apical fusion, and these are the Growth Guidance or Shilla screws.  These 10 screws will guide spinal growth along the straightened rods above and below, which is why the rods are left long.  As the spine grows the Growth Guidance or Shilla screws will slide away from the middle of the construct.

Please send me any questions you may have about this surgical procedure….

1.       Sanders JO, Khoury JG, Kishan S, Browne RH et al. Predicting scoliosis progression from skeletal maturity: a simplified classification during adolescence. J Bone Joint Surg Am 2008; 90(3):540

Tuesday, March 17, 2020

What is the best surgery for a patient with Early-Onset Scoliosis (EOS) who needs to have surgery?

This is a question parents commonly ask me in the office.  The question is a fair, reasonable question.  So why is it so hard for me to give an answer?  Well.....EOS is a problem which has many facets or things which need to be considered to be able to optimally answer the question.  Every child and every spinal deformity is unique: rib deformities (brown circle), spine/vertebral pathology/problems (purple circle), and differing underlying diagnoses (yellow circle) all need to be considered.  In addition, patient age, location of the deformity, patient height and weight, bone quality, etc…. also comes into play when we consider how to surgically treat a patient.

…and because each patient is unique….….

And for EOS surgery the three surgical “tools” we are going to talk about are:
1.       Traditional Growing Rods (TGR)
2.       Magnetically-Controlled Growing Rods or MAGEC (MCGR)
3.       Growth Guidance Surgery (GGS)

Like many of the decisions we make every day in life, identifying the goals or desired outcome of our actions is important.  For surgery we need to identify what “success” looks like....because if we don’t know what our goals are….we cannot determine if our surgery achieved it goals.  Below is a short list of the “Goals of EOS surgery”. 

So let’s look one-by-one at each one of these goals to see how the three most common surgeries for EOS compare.  Below is study we published comparing Growth Guidance Surgery to Traditional Growing Rods.

So this study reported similar outcomes for scoliosis curve correction, spinal height and surgical complications, with fewer surgeries in the Growth Guidance Surgeries compared to Traditional Growing Rods.

FYI: Distraction-based constructs are Traditional Growing Rods and Magnetically-Controlled Growing Rods

So what are the goals which appear to be equally treated by all three surgeries?

Let’s review how these 3 surgeries compare

When we look at our “Goals of EOS Treatment” you see how favorably Growth Guidance Surgery stacks up against Traditional Growing Rods and Magnetically-Controlled Growing Rods.  When I have a child who needs surgery I consider each of these methods of treatment, but the first one I think of is Growth Guidance, followed by Magnetically-Controlled Growing Rods and if neither of these surgeries can be performed I opt for Traditional Growing Rods.

Below is a typical patient, who at 9 years of age underwent surgery and is shown 3 years after surgery.  He only has had one surgery so far……

The last item I want to comment about is another question I sometimes get asked by parents who have seen other pediatric spine before seeing me: Why haven’t other surgeons offered Growth Guidance as a treatment option for my child?  Growth Guidance surgery has been around since the early 2000s, yet it has not caught on as a popular surgical technique, so it’s not like this is new procedure.  The main issue is Growth Guidance Surgery is a more difficult procedure to perform than Traditional or Magnetically-Controlled Growing Rods and it has been taught to pediatric orthopaedic surgeons at only a couple of medical centers in the U.S. with any frequency (Little Rock, Arkansas and St. Louis, Missouri).