Blog Post on Congenital Scoliosis                                           12-24-2020

 

Scoliosis can be broadly broken down into one of 4 types:

Idiopathic: meaning there is no known etiology

Syndromic: connective tissue disorders (Marfan’s, Ehlers-Danlos), trisomy 21, Prader-Willi, Retts syndrome, Beale’s syndrome, muscular dystrophies (e.g. Duchenne’s), osteochondrodystrophy (dwarfism), neurofibromatosis, Noonan syndrome, VATER/VACTERL, Angelman, Osteogenesis Imperfecta,

Neuromuscular: such as cerebral palsy, spina bifida, muscular dystrophies (e.g. Duchenne’s), paralytic conditions (e.g. polio, spinal cord injury), spinal muscle atrophy, Friedreich’s ataxia,

Congenital

 

https://www.srs.org/patients-and-families/conditions-and-treatments/parents/scoliosis/congenital-scoliosis

Of these, the idiopathic category is the diagnosis of exclusion, meaning patients can be given this diagnosis if there is no known cause of the scoliosis, there are no known significant medical comorbidities (see syndromic and neuromuscular categories, above) or atypical bony maldevelopment of the vertebra (congenital).

The categories of syndromic and neuromuscular (#2 and #3, above) are rather nebulous and there is some disagreement where to place certain diagnoses, such as muscular dystrophies.

The last category, congenital, is the one which is solely based on abnormal vertebral development.  So it is possible to have a patients which has congenital scoliosis, but also has a syndromic (e.g. VATER/VACTERL) or a neuromuscular diagnosis (e.g. spina bifida or myelomeningocoele) at the same time.

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Within the diagnostic category of congenital scoliosis there are three main sub-categories:

Failure of formation (meaning there are parts of the vertebra which never formed)

Failure of segmentation (meaning the parts of the vertebra did not separate as they were intended). 

Mixed type, which is a combination of the two above categories (failure of formation and failure of segmentation).

 

This is a classic figure from the work of Dr. McMaster which nicely demonstrates Defects of Segmentation and Defects of Formation.

More about congenital scoliosis next week……

12-19-2020

Our latest Idiopathic Scoliosis Bracing Handout, courtesy of Keith Patten, FNP-C

 

 

Vertebral Body Tether of Lumbar Scoliosis Curves                                                        11-30-2020

 

Over the last 15 years there has been an increasing interest from patients and families in non-fusion solutions for scoliosis.  Vertebral Body Stapling (VBS) was the first non-fusion technique reported for treatment of idiopathic scoliosis, in the 1950s.  Due to the lack of advance implant technology the technique disappeared for 40+ years, but re-appeared in the early 2000s when newer high-tech implants became available. 

 

At the same time a parallel implant system, Vertebral Body Tethering, was also being developed.  Due to the ability to exert a stronger correction force to the spine VBT gained traction, since it can treat curves up to 60 degrees.  In comparison, VBS failed to maintain traction, mainly due to its lower correction force and its application only in smaller scoliosis curves (35 degrees).  Over time VBS faded, and at present there are no commercially available implants in the U.S. to perform VBS.

Many studies from around the world have reported on VBT, but most have focused on its application in the thoracic spine. 

 

 

Thoracic spine (in blue) and lumbar spine (in pink)

Though the thoracic spine has some intervertebral motion, the lumbar spine has vastly more motion at each intervertebral disc.  Conceptually it makes sense that VBT would have a greater impact on preserving spine motion, than fusion, in the lumbar spine.  So why have pediatric spine deformity surgeons focused on the application of VBT in the thoracic spine, if there may be less benefit than the lumbar spine?

Two reasons for this are:

1.      The surgical approach to the thoracic spine can be accomplished with a minimal number and length of surgical incisions, due to the use of a thoracoscope (camera inserted into the chest through small incision to view the spine through the chest).  This is obviously attractive as it leaves small aesthetically reasonable scars.  Surgeons with experience in thoracoscopic spine surgery (VBS and fusions) have considerable expertise with this approach and area of the spine.

2.      The most common curve patterns seen in idiopathic scoliosis are in the thoracic spine.  So surgeons are seeing much more scoliosis in the thoracic spine than the lumbar spine.

 

So what do we know about the use of VBT in the lumbar spine?  Overall not very much. 

There are only two studies, published in 2020, which specifically report the use of VBT in the lumbar spine. There are 6 important points of these 2 studies:

1.      1. Both of these are early-outcome studies with a minimum follow-up after surgery of 2 years and a mean follow-up in both studies of approximately 3 years.  This is very short follow-up for patients who will live another 60+ years. There is no long-term data on VBT.  What will happen long-term to the lumbar spines with a tether placed across the discs?  Will they become arthritic?  Will they cause pain? 

2.      2. Combined they report only on 9 lumbar curves, as opposed to the thoracic spine which have 100s of cases reported in the literature. 

3.      3. Tether breakage in 47-48% of all patients (thoracic and lumbar)

4.      4. Success rates of 53-74%

5.      5. Reoperation rates of 21-24% (1 patient out of 5 underwent a repeat surgery)

6.      6. VBT should only be done in patients with growth remaining.  It is not indicated in skeletally-mature patients (Sanders 7-8 or Risser 4-5)

In contrast to these VBT data, lumbar fusion surgeries for scoliosis have a long history, a high rate of success and low frequency of reoperations.

Picture credit: https://whyy.org/segments/rope-or-rod-torn-between-scoliosis-surgeries/

 

So which way should you go?  Lumbar VBT or Lumbar fusion surgery?

There are many factors which can go into the decision-making process of informed consent and should be discussed in detail with a surgeon who has experience in both approaches.  So I can’t tell you which surgery you or your child should have.

If motion preservation is an important aspect of scoliosis surgical treatment to you, then it is imperative you are fully informed as to the alternatives, benefits, complications and risks of VBT.  No surgery is without risks and potential complications.  If you fully understand the above-mentioned data, then VBT may be a reasonable procedure for lumbar scoliosis in you or your growing child. 

VBT holds significant promise.  I personally believe that VBT, or some variant of it, which can preserve spine motion and correct scoliosis will be eventually be highly successful with long-term outcomes.  However until that time, caveat emptor or “let the buyer beware". 

 

 

 

 

Spine Deformity Surgical Wound Healing                            11-24-2020

 

Back in July (7-28-2020) I published two blog post on spine wounds, specifically the concepts and methods used to close the incisions used during spine surgery, mainly posterior spinal fusion incisions in pediatric and adolescent patients.

As I explained previously the goal in the end is a nice narrow (or thin) scar which blends into the individual’s normal skin tone.  What we want to avoid is a wide scar which has a different color and/or skin tone compared to the individual’s normal skin.  Simply put, we want the scar to be as unnoticeable as possible.  Spinal deformity surgery currently requires longer incisions, so we do whatever we can do to make the surgical scars more aesthetically pleasing and as “invisible” as possible

 

Preoperative

Typical appearance of the back of an adolescent with idiopathic scoliosis

 

 

Discharge from the hospital 3 days after surgery

Notice the thin strip of glue on the skin, this surgical glue seals the incision.  The glue typically falls off around 3-4 weeks after surgery. The small wound dressing, below picture on the right, is where the surgical drains were placed, and were now removed.  This dressing is removed after a couple of days and the small holes where the drains came out will be healed.

The back tissues are also swollen, which is normal after surgery.  This patient is only 3 days after surgery.  The purple markings are from the skin marker we use during surgery, which has not yet worn off.

 

 

 

2 years postoperatively (same patient which was 3 days postoperatively)

The surgical scar has completely remodeled.  It is narrow and similar to the patient’s normal skin tone.

The normal contours of the back are now present as the postoperative swelling which was present in the previous picture has long been resolved.  The incision is in the hollow of the back.

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Here is another adolescent patient

She is only 3 days after surgery.

 

Here she is now only 6 weeks after surgery

Notice the glue is all off the incision….

The back is a little swollen and the skin at the scar is slightly pink and raised.  Over the next 6-12 months the scar will fade to the patient’s normal skin tone, the pinkness will resolve and the swelling will return to baseline.

 

“Internal Dis-traction”

The last 4 posts have been on spine traction, and this is the last one, which details the third type traction we use in pediatric and adolescent spine deformity surgery: Temporary Intra-operative Distraction Rods (TIDR).  This type of traction, like Halo-Gravity and Intraoperative Halo-Femoral Traction, are used for the correction of severe scoliosis.  Each of these have positives and negatives.  In general, in most instances in which halo traction is considered for a thoracic or lumbar spinal deformity, TIDR may be also be considered.  The only absolute requirement is the presence of sufficient temporary bony fixation points in which to anchor the rods near the top and bottom of the deformity.  Anchor points may include the spine, pelvis or ribs.  This technique can be utilized in situation with cervical problems (i.e. deformity or instability) or distal deformity (i.e. hip flexion deformity). 

 

This picture shows how the upgoing rib hooks are positioned and push upwards (red arrow).  By pushing up on the ribs, which are attached to the spine, the scoliosis is stretched straighter. 

 

 

 

 

 

The below case is a 14 year old with severe idiopathic scoliosis of 110 degrees, for which the Temporary Intra-operative Distraction Rods (TIDR) was used during surgery. 

 

The first stage of the surgery was to expose the spine, perform osteotomies (to loosen up the spine and get better scoliosis correction) and place the TIDR.  In this case we placed 4 rib hooks (green arrows in intraoperative photos and green circle on accompanying x-ray).  When we distract the rod (direction of blue arrows) you can see how much correction was obtained (110 degrees down to 61 degrees), when compared to the above x-ray before surgery.

The patient was brought back one week later to complete the surgery, which was to remove the TIDR and place two new spinal rods (and get more correction).  The final scoliosis measurement is 40 degrees!  A huge correction!

 

We don’t need to use this technique often, but when we do it can often be extremely helpful!

 

  

Intraoperative Halo-femoral Traction Part 2

 In nonambulatory neuromuscular scoliosis (i.e. cerebral palsy, spinal muscle atrophy, myelomeningocoele, muscular dystrophy) progressive scoliosis with long, sweeping curves can cause significant tipping of the hips which can create sitting imbalance, pressure sores and pain. 

 

12 year old female with spastic quadriplegic CP

 

The goal of surgical treatment for this population is different than for the idiopathic scoliosis patient, specifically to correct the tilt of the hips and to obtain, and maintain, a painless, well-balanced spine above the pelvis.  Hence the aim is to establish a good sitting balance, as you see below.

 

 

 

 

 

 

Here she is now 5 years after surgery

 

The major challenge in the surgical correction of neuromuscular scoliosis is how to obtain spinal correction and, secondarily, how to maintain this alignment during the postoperative period. 

 Soft bones is a common problem which poses challenges in how to obtain spinal correction. 

 The use of intraoperative halo-femoral traction (IHFT) allows direct skeletal traction and correction of the spinal deformity and pelvic obliquity. 

 

Pulling up on the halo helps center the head over the hips, and pulling down on the hip that is higher helps level the hips.

 

During the surgical procedure most, if not all, the correction is obtained by the IHFT obviating the need for significant spinal implant manipulation for correction. 

 

In this 13 year old female with spastic quadriplegic cerebral palsy, who in the second x-ray is in surgery, it is easy to see how the scoliosis is improved and the hips more level, simply due to traction.

 

By off-loading the implants the chance of loosening losing fixation at the bone-implant interface is lessened.

 

Here the patient is 5 years after surgery with excellent three-dimensional spine position and a solid spine fusion. 

 

Intraoperative Halo-femoral traction                           10-23-2020

As mentioned in the previous blog post, the use of halo-gravity traction (HGT) before surgery is a safe and very effective technique to improve severe spinal deformity, prior to a corrective surgical procedure.  On one end of the spine, the head, a carbon-fibre frame is placed onto the skull and a vertical force is placed on the spine via weights and pulleys.  On the other end is simply the patients’ body, so there is a limit as to how much weight we can apply without suspending the patients off the floor!  The other limitation for HGT is that, since body weight is used on the lower end, the spine deformity we are trying to correct cannot be too low, such as in the lumbar spine.  This is due to the fact there is less body weight below this area to pull against and hence hard to change the deformity as much when compared to deformities in the neck or chest (thoracic spine).

 

So, can we put a point of fixation below the area of spine deformity that will allow us to pull harder, before surgery?  The answer is yes, but the use of preoperative halo-femoral/pelvic/tibial traction has been shown to have an unacceptably high complication rate (1-3).  Despite this the technique has shown to be effective in preoperatively correcting coronal deformities (41-57%) and pelvic obliquity (up to 53%) (1-2). 

 

However, we can use this concept to help improve spinal deformity.  The place we can, and do, use this type of traction is in the operating room during the scoliosis correction surgery.  By using this method intraoperatively, one can avoid the problems associated with long-term traction yet gain the benefits of direct axial traction during the surgical procedure. 

 

Below is a patient, during surgery, with a 4-pin halo frame applied (green arrow), which is attached to a wire bale then to a rope (red arrow) which then goes to a weight.  This applied a pull in the direction of the red arrow.

On the opposite end (below), a pin is place across the femur just above the knee joint (green arrow) and is attached to a bale and rope which then pulls down (direction of red arrow). 

Both the halo frame and the traction pin in the femur are placed AFTER the patient is asleep under general anesthesia, and they are removed BEFORE the patient wakes up after surgery is completed.  Hence, there is no pain to the patient during the placement or removal of the halo or traction pin.

 

The next post will delve deeper into how we use this type of traction to improve our surgical outcomes.

 

 

1.     Bonnett C., Perry J., Brown J.C., et al:  Halo-femoral distraction and posterior spine fusion for paralytic scoliosis.  J Bone Joint Surg [Am] 54:202, 1972.

2.     Kane W.J., Moe J.H., Lai C.C.:  Halo-femoral pin distraction in the treatment of scoliosis.  J Bone Joint Surgery [Am] 49:1018-1019, 1967.

3.     Ransford A.O. Manning C.W.:  Complications of halo-pelvic distraction for scoliosis.  J Bone Joint Surg [Br] 57:131-138, 1975.

 

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.