Vertebral Column Resection (VCR) in Pediatric Spinal Deformity

Part 3

4-25-2021

The last two blog posts were about the concept of VCR and the initial steps which are done, just before a VCR is performed.  This post will talk about how a VCR is actually completed.

 

How is a Vertebral Column Resection Performed?

After the incision, spinal exposure and placement of pedicle screws the next important step is to place a rod across the VCR site (see below at green arrow).  This is important as a VCR significantly destabilizes the spine, and not having 1 or 2 rods across the VCR the spine can move, or subluxate, which can cause the spinal cord to not function normal.

Next, the VCR step is to carefully remove the vertebra of interest, piece by piece, working from the back of the vertebra to front. The back, or roof, of the spinal column if first take off, to expose the spinal cord (see blue arrow in the surgical photo and the red arrow in the drawing).

The 2 ribs connected to the vertebra of interest are identified and exposed the medial 4-5 cm of the ribs are removed.

 

After the lamina is resected, retractors are placed around the vertebral body to safely expose the bone and protect the vital structures on the sides and in front of the spine (see below, red and black lines).

 

See the operative picture below for the retractor (green arrow)

 

Next the pedicles (see red arrows in below diagram), the column of bone which connects the back or roof of the spinal column to the vertebral body are resected. This would leave only the vertebral body (#1).

 

 

Now the spinal cord can be seen on the back, left and right side.  The bone of the vertebral body is the carefully removed (below) with curettes and drills.

After removal of the body…the discs on each side of the VCR are then removed (see below).

 

Once the vertebral body is completely removed, the spinal cord is a tube which bridges from one vertebral to the adjacent vertebra (green arrow below). 

It is now time to take the deformed spine and realign it to a better position, which is done by bending the rod and compressing the spine above and below the VCR defect site together (see below)

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Sometimes the space can be completely closed down, bone on bone.  Other times a small “cage” is needed to bridge the gap.  This is important from a spinal stability and healing of the bone fusion.  A gap in the front can allow too much movement of the spine and prevent the fusion from healing, causing the rods to break or screws to move or pull out of the bone.

 

A cage was used in the surgical case shown below (red arrows)

Once good spinal alignment is achieved, the spinal column is stabilized with 2 or more rods, in its new and improved position.

All the implants (pedicle screws, hooks, cages and rods) help to attain the new spine alignment, but also maintain it until the spine fusions set up and is durable.  The development of a spine fusion can take several years to get hard and durable.

 

Vertebral Column Resection (VCR) in Pediatric Spinal Deformity

Part 2                4-19-2021

How is a Vertebral Column Resection Performed?

A vertebral column resection is performed under general anesthesia, which means the patient is asleep or unconscious, on a breathing machine (ventilator) and is face-down on the operating room table.

 

 

 

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Here is one of our spine nurses demonstrating how someone is positioned in the OR.

Spinal cord monitoring of the sensory tracts (e.g. light touch) and motor tracts (muscle control) are used throughout the procedure to help ensure the safety of the spinal cord.  The spinal cord is monitored electrically, and the signals are like an EKG (electrocardiogram) of the heart.

The surgical approach almost always only posterior (from the back) only. A skin incision is make and then back of the vertebral column is exposed.

Pedicle screws are placed from the back and into the body of the vertebra.

Radiographs, or x-rays, confirm the appropriate placement of the screws into the spine.

The screws will later be connected together with rods to help stabilize the spine.

All the above steps are necessary before a VCR is done.

The next blog post will show how a VCR is completed.

 

Vertebral Column Resection (VCR) in Pediatric Spinal Deformity

4-18-2021

 

What is a Vertebral Column Resection (VCR)?

A VCR is complete surgical removal of one, or more, vertebra.  It is always combined with posterior spinal fusion and instrumentation.  This means screws, rods, and possibly cages are used to hold the spine in the new alignment while the spine undergoes bony fusion. Example C below.

A VCR is also called a Three-Column Osteotomy or a Corpectomy.

 

When is a VCR needed?

A VCR may be needed when a severe, rigid spinal deformity is to be corrected. It can be used to treat hyperkyphosis (abnormal forward curvature of the spine) or scoliosis (abnormal side curvature of the spine).

 

Why would more than 1 vertebra be removed?

Removal of a single vertebra can permit 80+ degrees of correction.  Despite this fact a 2^nd vertebra may also need to be removed to achieve the desired correction safely.

 

What happens to the gap between the vertebra after a VCR?

After a VCR the two ends of the spine can be moved in space to correct the spine deformity.  Ideally there is no gap, and the vertebra can be moved so that there is bone-on-bone contact.  However, at times there is a gap after the spine deformity is corrected.  The presence of a gap or hole is dependent upon the type and severity of the spinal deformity. If there is a gap a “cage” is placed which struts from the upper vertebra to the lower vertebra. 

 

Why is a “cage” sometimes placed?

A “cage” strengthens the surgery, by providing a strut from vertebra to vertebra on the front side of the spinal cord.  The usual spinal instrumentation is placed in the back of the spinal cord.  So a “cage” gives 2 areas of stabilization for the spine.  This can increase the likelihood the instrumentation holding the spine and a successful fusion of the surgery.

 

Below is a 10 year old female with Neurofibromatosis Type 1 and a progressive kyphosis.  On the left x-ray the vertebra with the red arrow pointing to it was removed.  On the right, the blue arrow points to the “cage” which was placed at the defect site, to support the spinal column in front of the spinal cord.

Next week we will go over how we do this surgery.

 

https://rdcu.be/cizNe

 

Blog Topic:  “How much correction of the scoliosis did you get during surgery?”

 

This is a common question asked after spinal deformity surgery.

Parents and caregivers are interested in how close their child’s spine was able to be returned to a “normal” alignment on x-ray.  It is a very reasonable question.  I would probably ask a similar question if my child was having scoliosis surgery.  As a parent, I would want my child’s spine to be as close to “normal” as possible.  At first glance it would appear to make sense that the closer the spine correction was to 100%, the better the person will look, the less pain they will have in their back and the better they will function now, and for the long-term.  This however is not often true.  To explain why this is the case, a few important facts/points must be first presented:

 

#1           Scoliosis is a 3-dimensional spine deformity.  The spine twists as it turns, much like a water slide that banks when the slide turns side-to-side.  For a more detailed explanation of this please go to the blog post on 6-6-2020.

 

#2           The x-rays we take of the spine can only easily document 2 of the 3 planes of the scoliosis (coronal and sagittal plane, see below).  The third plane is the axial or transverse plan, which is the “twisting” of the spine.  Sometimes there is a lot of twist in a scoliosis, and sometimes there is not much twist.  Each child and scoliosis is different.  It is hard to measure the twisting of the plane on the x-rays.

              

We can more easily measure the amount of twist or rotation of the spine in the office using the scoliometer (see below).

 

#3           When we talk about how much the scoliosis changes the body, from the patient’s perspective, we really are trying to assess how much different the right side is from the left side of the body.  How asymmetric is the body side-to-side.

#4           The outward changes to each person’s body, by the scoliosis, is unique.  For example, two people could have a 60-degree scoliosis, with one person having a lot of changes to their body, while other person has very little obvious asymmetry.

As a surgeon, we often try to achieve maximal 3-dimensional correction (see the below radiographs).  It is important to note the x-ray which shows the scoliosis is the view from the front/back of the patient, and is only in a single plane (coronal plane).  However, scoliosis is a 3-dimensional problem, as I explained in a previous blog post when I talked about the abnormal rotation of the spine and how we can correct this in surgery.  Sometimes the transverse plane or axial plane, which is what cause the rib prominence and asymmetry, may be the most aesthetically important part of the deformity.

So when the surgeon answers the parent/caregiver’s question and says “80%” they are only referring to correction in only one plane of a 3 plane problem (coronal plane).  However, as a surgeon I know that maximally correcting a scoliosis is not always desirable, or safe. If you make the spine completely straight over the areas you operate, the spine above and below the surgical area may suffer secondarily and then cause pain, spinal instability and need further surgery.

 

The next blog post the reason why we don’t always want 100%, or even 90% of the spine deformity, will be presented.

 

Blog Topic:  Surgeon Recommendations after surgery

Sometimes our precious patients listen to us and other times…………………………………………not so much.