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-