Halo-Gravity Traction                                                                       9-30-2020

https://www.shrinershospitalsforchildren.org/st-louis/news-and-events/lily-stands-tall-after-spinal-fusion--243

 

https://www.shrinershospitalsforchildren.org/st-louis/halo-traction

Earlier this spring I put up three blog posts on Halo-Gravity Traction.  I will briefly re-present it here as a way to launch into the two other types of traction we utilize: Intraoperative Halo-Femoral Traction and Internal "Dis-traction" Technique.

What is halo-gravity traction?

As you see from the three young patients above, a “halo” is applied to their skulls when they are asleep in the operating rooms.  On the two boys their halos are black, as they are made from carbon fiber, while the young lady’s halo is so nicely bedazzled you don’t see any of the black carbon fiber material. Attached to the halo you see two straps or an inverted-V which is then attached to a rope which is pulling upwards, towards the ceiling.

The rope goes through a series of pulleys and finally attach to weights.

Why do we put patients into halo-gravity traction?

The below case is a nice example of why we use halo-gravity traction, a 5 year old female with severe early-onset scoliosis at 104 degrees (picture on left) and 91 degrees of kyphosis (2^nd picture from right).  After 7 weeks of traction the scoliosis decreased to 75 degrees (a 28% improvement!) (2^nd picture from left) and 40 degrees (a 57% improvement) of kyphosis (picture on right).  Overall there was an 80 degree improvement in the spinal deformity! This was all done only with halo-gravity traction, and no spine surgery.

In general, we apply preoperative traction for any severe spinal deformities, which can be curves greater than 90 degrees.

How does it work?

Spinal traction takes advantage of the viscoelastic properties of the spinal column. Think of the spine like a spring, a person with scoliosis would be the spring on the far left, crooked/twisted and very short from the top of the spring to the bottom of the spring.  As we apply more and more weight to the spine, the curves straighten out and the spine gets longer.  In the case demonstrated above the spine lengthened (from the bottom of the neck to the pelvis) a total of 69 mm or 2.7 inches!

 

However there is a limit to how much weight we can safely put through the traction apparatus.  This maximal limit varies patient to patient but we typically don’t go higher than 50% of the patient’s body weight.

In next blog post we will demonstrate another type of traction: Intraoperative Halo-Femoral Traction

 

Spine Traction in Scoliosis            9-23-2020

Question:

My child’s spine doctor says they want to use “traction” on my child’s spine.  This sounds scary.  What is it?  Is this something new?  I have never heard of it.

Answer:

Spine traction to correct spinal deformity is not a new concept; in fact, the first applications were reported in ancient Hindu mythological epics (3500-1800 BC)(Kumar K.:  Spinal deformity and axial traction.  Spine 21:653-656, 1996). Hippocrates (c. 460 BC – 380 BC) could be considered the first to study the spine and spinal deformity, and introduced the terms “scoliosis” and “kyphosis”. He invented the Hippocrates Bench or Board through which the patient’s spine was stretched, while awake, to help with their spinal deformity.  The traction was applied by pulling on the head and neck on one end, and pulling down through the legs on the other end.  A winch would gradually increase the stretch on the spine, then a practitioner could then push on the spine to induce a corrective force to the chest and spine.

 

 In addition, he developed the Hippocrates Ladder which hung the patient upside down or head up.  This traction method used gravity to improve the spine deformity.  Almost 5 centuries later Galen of Pergamon (c. 130-200 AD) furthered the concepts introduced by Hippocrates and advanced the entire field medicine in many ways.

 

Traction for spinal deformity correction fell into disfavor due to the production of spinal cord injury and paraplegia created by the application of excessive distraction to the spine. 

However, over the last three decades, with refinement in the knowledge of spinal anatomy and biomechanics, the concept of controlled axial traction has regained attention with the use of the Harrington outrigger, Cotrel traction, and halo traction. 

In the next three posts I will outline the 3 most commonly-applied techniques of spinal traction currently in use:

1. Preoperative halo-gravity traction
2. Intraoperative halo-femoral traction
3. Internal “dis-traction” technique (Table 1).

The purpose of spine traction in 2020 is to improve spinal deformity safely and then apply a spine cast or spinal implants to further correct the spine deformity and to maintain the improved spine position.  Traction has been shown by multiple authors and centers to be a safe procedure which improves the outcomes of casting or surgery.  We use all three of the above-mentioned traction strategies at Washington University School of Medicine, at our Shriners Hospital for Children and St. Louis Children's Hospital. 

The below table highlights the strengths and weaknesses of each type of traction we will discuss in the upcoming blog posts……..

	Strengths	Weaknesses
Preoperative Halo-gravity	1. Permits gradual application of traction 2. Correction while patient is awake 3. Low risk of neurologic problems	1. Requires weeks or months of continuous, daily treatment 2. Pin site issues 3. Contraindicated for cervical and occipito-cervical instability
Intraoperative Halo-femoral	1. Preoperative hospitalization unnecessary 2. Can easily adjust traction force to achieve desired correction 3. Improves pelvic obliquity 4. Decreases operative time	1. Additional operative time for halo application and traction pin insertion with scarring 2. Contraindicated for cervical or occipito-cervical instability 3. Relative contraindication with kyphotic deformity
Internal Dis-traction	1. No external force application	1. Shorter-term application of traction; less stress relaxation and creep

 

 

Spine Osteotomies                             

 

So your surgeon want to “cut” your spine….that just doesn’t sound good, does it?

Well what are they talking about “cutting” the bone of your spine? To surgeons it is call an “osteotomy” which, if you break the word down to its latin roots, means bone (for “osteo”) and cutting part of the body (for “otomy”). 

The first spine osteotomy was done by an Italian surgeon, Alberto Ponte, in the mid-1970s for increased kyphosis or rounding of the back.  Dr. Ponte wanted to loosen the spine to get better correction of spine deformity, so he removed bone and soft tissue between vertebra, done all from the back side. Over the last 40+ years these osteotomies have been used around the world for all types of spine deformity.

So how does your surgeon do these osteotomies?

STEP 1: The goal is to completely remove all bone and soft tissues between the vertebra. So the first step is to remove some bone (below shaded area) from the upper vertebra.

 

STEP 2: Once that is done the soft tissue in midline, call th
e ligamentum flavum (the vertical white tissue which looks like vertical blinds) is carefully removed.

 

STEP3: Next the bone on the lower vertebra is removed….

This creates a complete gap between the vertebra (see below picture at orange shaded area)

 

 

 

 

STEP 4: The pedicle screws are then placed….and the spine is ready to be corrected to a better position

 

 

***So is this a safe procedure to do the spine?  In the below research study we analyzed the complications of doing spine osteotomies in pediatric and adolescent patients at Washington University. 

484 osteotomies in 142 patients were studied and there were 0.4% frequency of complications (2 patients had dural tears that were repaired in surgery).  So yes, these can be very safe procedures to perform.

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This is a good reference:

https://surgeryreference.aofoundation.org/spine/deformities/adolescent-idiopathic-scoliosis/basic-technique/large-curves#posterior-column-osteotomy-pco-

    This new publication emphasizes the need to maximize lung volumes in patients with early-onset scoliosis. 

Closure of Spinal Deformity Wounds

The long-term appearance of a planned surgical scar is a common concern before surgery.  Sometimes this question is asked to us, other times it is not, likely because people do not want to appear overly concerned or vain about appearance or aesthetics of their skin.  Either way, the concern exists and is valid. Why would anyone want a wide, unattractive scar?

So how do you close the below surgical wound safely and so that it has the narrowest scar long-term?

Our method of wound closure in pediatric spine is influenced by several factors:

1. Location of the wound: Back incisions, though easy to hide under shirts and tops, can easily be seen when the child/adolescent is not wearing a covering (e.g. swimming).

2. Desire to minimize the visibility of the surgical scar.

3. Patient intolerance, anxiety and/or distress when non-absorbable sutures or staples need removal. 

4. We want to avoid the need for additional outpatient visit for surgical wound suture or staple removal

In the operating room, at the end of the surgical procedure, the surgical wound is closed in two layers, the deep spine fascia (black arrow) and the skin (red arrow).  The fascia is a strong covering over the muscle, and this is the first layer to close.  It is important to close this tightly to get the appropriate healing after surgery.

The second layer is the skin (small red arrow in above picture).  This layer is actually closed with two separate suture layers

The first layer is deep dermal layer (red suture in below picture) which closely re-approximates the skin edges.  This takes the tension off the edges of the skin.

The second layer is the subcuticular or epidermal suture (blue suture in picture above).  This uses a small suture woven back and forth just barely underneath the surface of the skin.  It is this layer which gently puts the edges of the skin against each other to minimize the amount of scar tissue which develops.  A gap will require scar to heal the area, and this never leaves an attractive scar.

Lastly the skin in sealed with a glue.  This glue also helps the skin edges to be very close together and minimize motion.  It also nicely seals the skin watertight.  This glue usually starts to fall off about 3 weeks after surgery.

We don’t use sutures, steri-strips or staples in our skin closures.

They don’t leave as nice a wound as we want

We want to avoid our wounds looking like this

Instead this is the way we want our skin closures to look. This is only 4 weeks after surgery!

Next blog post we will show pictures of surgical wounds, after surgery, to demonstrate the nice progression of healing with our technique.

Spine Rotation in Scoliosis (part 3): How we correct spine malrotation and rib prominence during spine fusions

In the last 2 posts I showed how scoliosis is a 3-dimensional problem, with the spine rotating around itself as it bends to the side.  The way to visualize this is to imagine a water slide, as it turns to the side, it also rotates…just like the spine in scoliosis and how the spine twists the ribs around.

This post will show how we can improve the spine and rib position during a spine fusion surgery.
The case example is a 14 year old young lady with a 58 degree right thoracic idiopathic curve, and 35 degree proximal thoracic and 24 degree lumbar curves.

The supine side bending radiographs demonstrate the flexibility of the spine.  So only the main thoracic curve of 58 degrees is what we call “structural” and the other two curves, due to the fact they bend out to be below 25 degrees, we call “nonstructural” or “compensatory”.

In order to maximize 3-dimensional correction and long-term outcome, while minimizing need for any additional surgeries the plan was to do a T3 to L1 posterior spinal fusion.  T7-T8 and T8-T9 PCOs, or posterior column osteotomies were also performed.  These osteotomies (PCOs) are done at the time of surgery to increase spine flexibility in all 3 planes, to maximize spinal deformity correction to as close to “normal” as we can safely achieve.

Pedicle screw are the optimal method of spine fixation.  They allow rigid fixation to the spine, and permits the spine to be moved 3-dimensionally.  Not every vertebra needs to have 2 screws.  Strategically placing screws to optimize immediate correction and assure long-term outcome is preferred, so about 1.5 screws per level is common.
By placing the screws at certain locations, specifically at the apex, the spine can be derotated back more toward normal.

The silver towers or rods are attached to the screws (picture on left), and then these towers are connected together to improve strength of the spine fixation (middle picture).  This connection process, for this patient, make 3 groups, one for each curve.  These 3 groups of towers/screws are then rotated back toward normal (picture on right).  You can see the different position of the middle group, relative to the other two groups, between the middle and right-sided pictures.  Once rotated to the improved position (right picture) the screws are then tightened down, and much more work is done in surgery to 3-dimensionally improve and balance the spine.

These postoperative radiographs are one year after surgery.  The patient is nicely balanced 3-dimensionally and has nicely improved.

Spine Rotation in Scoliosis (part 2)

In the last post I showed how scoliosis is a 3-dimensional problem, with the spine rotating around itself as it bends to the side.  The way to visualize this is to imagine a water slide, as it turns to the side, it also rotates…just like the spine in scoliosis.

What is interesting is that each patient is unique in the amount of rotation of scoliosis, some have more rotation, and some have less for the exact same amount of scoliosis.  While the rotation of the spine has not yet been shown to impact the long-term functional outcome of the spine, it DOES impact the physical shape of the body.  The rib prominence in the back causes the shoulder blade to be prominent.  The rotation of the ribs also impacts the body in the front, by making the ribs stick out more on one side and can cause breast asymmetry.  So the greater the rotation of the spine, the more physical deformity of the body.

When the scoliosis is smaller, somewhere between 20 and 45 degrees, bracing is typically a treatment option.  When a scoliosis brace is applied to the body it is molded to push against the rib prominence, to try to prevent the scoliosis to continue to progress and rotate more.

 

When the scoliosis gets to more than 45 degrees, bracing is not very effective because it cannot exert enough force on the ribs to prevent the spine from progressing.  Surgery can be an option for curves >/= 45 degrees.  If surgery is an option, the amount of rotation in the scoliosis is important to determine, and is usually done using a scoliometer (see below).

This is a measurement from horizontal; similar to an inclinometer. 

As mentioned in a previous post on vertebral body tethering, rotation of more than 20 degrees is a relative contra-indication to a tether procedure.  This is because a tether does not significantly alter the rotation of the spine, so if the spine is corrected with a tether, there still may be permanent physical deformity due to the residual rotation of the spine.  In these circumstances, specifically a curve 45+ degrees with more than 20 degrees of rotation, a spine fusion may be a better option.

A successful surgery depends on quantifying the spinal deformity, identifying what are the major (and lesser) cosmetic/aesthetic/physical body concerns, and then developing a strategy to maximize correction safely.

In the next post the surgical correction of pediatric scoliosis will be demonstrated, mainly focusing on correction of the rotation.  So if you don’t like surgical photos, and a little blood, then don’t view the next post!