What is Cervical Disc Arthroplasty (CDA)?

Cervical Disc Arthroplasty (CDA) is a relatively new procedure that is used to treat Disc Associated Wobbler's Syndrome (DAWS).  It was developed by Dr. Filippo Adamo ECVN, the inventor of the artificial disc implant that we use in the procedure (The Adamo Spinal Disc).  Dr. Adamo created the technique based on disc replacement surgeries that are done in people because of the tendency for DAWS patients to develop a 'domino lesion' of DAWS in the adjacent discs shortly after surgical correction of the first lesion.

This is a picture of the instrument table and set-up before placing the disc implant in a patient.

The disc implant serves two purposes in treating DAWS.  First, it distracts the intervertebral space to relieve the compression on the spinal cord.  This is similar to the stated goal-of-therapy of several of the older procedures as well.  But where the CDA procedure differs, is in it's ability to maintain movement and range-of-motion at the surgical site.  By maintaining the dynamic nature of the intervertebral disc space, the CDA technique seeks to minimize the effects on the adjacent discs and prevent the dreaded 'domino lesion'.

We can place more than one disc implant in a patient when indicated.

The Adamo Spinal Disc is currently in it's 5th iteration.  The current design uses state-of-the-art manufacturing techniques and materials to improve the device and the surgical outcome for our patients.  

This is the complete Adamo Spinal Disc implant.  The white material on the back of the implants promotes bony fusion between the vertebrae and the implant.

First, the device is made of surgical grade titanium.  This lightweight and durable metal is also MRI safe.  Which means that we can safely repeat MRI studies of the patients if needed after the surgery.  In fact, repeat MRI studies are part of our post-operative evaluation for this procedure.  Because the technique is so new and cutting edge,  LOVN performs these post-operative MRI studies for these patients at no cost in exchange for using their outcomes and data for future studies and scientific papers.  That's how much we believe in this procedure!

Second, the device uses a small thermoplastic articular surface to maintain the movement at the site.  It works just like a 'ball and socket' to allow the two parts of the implant to move relative to one another.  If the contact surfaces were made of metal, small microparticles would be produced from the friction and could lead to worsened inflammation or other problems.

Here you can see the two parts of the Adamo Spinal Disc and the 'ball and socket' articulation between the two.  You can also see the screw threads that allow us to remove the positioning pins once the implant is in place.

Finally, the surface where the implant contacts the end plate bone of the vertebrae is specially treated in two ways to help in the healing process.  First, the surface is treated in a very special way to create titanium 'pores' or tunnels that encourage bone growth into the implant.  Once the bone grows into these 'tunnels' the interface between the bone and the implant becomes incredibly strong and durable.  Secondly, the titanium porosities are coated with hydroxyapatite crystals.  This is the same material that your body produces to create bone.  It serves as a substrate to speed up the bone growth into the pores and the ultimate incorporation into the vertebrae.

What is a CUSA?

CUSA is the acronym for cavitronic ultrasonic surgical aspirator.  This is an amazing device that is used in tumor surgery in a select number of hospitals around the world, and even fewer veterinary hospitals!

The CUSA uses ultrasonic frequencies to basically emulsify the target tissues.  The ultrasound waves cause the cells to dissociate from one another while the device irrigates the area with sterile saline.  The same handpiece then aspirates the fluid back out of the surgical site.  Because the device can be fine-tuned, it allows the surgeon to remove tumors with minimal effect on the adjacent tissues.  It can even 'skeletonize' the blood vessels which massively decreases the intraoperative bleeding!

We use our CUSA for removal of brain tumors, spinal cord tumors, and other delicate procedures involving the central nervous system.  Our SonoCure is the premier CUSA developed exclusively for veterinary use.  One of the most amazing parts of this device is the bone tip.  By using an exclusive technique of delivering longitudinal-torsional movement, the bone handle can emulsify (or liquify) bone in very delicate areas while protecting the vital tissues just next to it!

The bone tip uses a special longitudinal-torsional movement to add unparalleled precision to removal of bone immediately adjacent to delicate and vital tissues.

The addition of the SonoCure CUSA to our equipment at LOVN is just another way that we strive to provide the very best in medical and surgical outcomes for you and your pet!  To remain on the cutting-edge of surgical technique and technology is our promise to you.

What is Caudal Cervical Spondylomyelopathy (CCSM)?

This blog post is going to discuss the second form of "Wobbler's Disease" in dogs, Caudal Cervical Spondylomyelopathy or CCSM.

The breeds most commonly affected with CCSM include the Mastiffs and the Great Dane, but almost any large breed dog can be affected.  Typically, this condition is seen in younger dogs as it is a developmental problem (contrasted with the degenerative problem that causes Disc Associated Wobbler's Disease or DAWS).  

Again, to contrast with DAWS, the compression of the spinal cord is due to bony changes rather than discs, tendons, ligaments, or soft tissues.  The parts of the vertebrae that form the bony tunnel of the vertebral canal develop abnormally and are thickened towards the tail-end of the vertebrae.  This bony thickening is most noticable along the lateral (side) walls of the tunnel called the pedicles.  So, the compression is from the side in CCSM, whereas it's mostly top-to-bottom with DAWS.

Once again, there are two different options for therapy, medical management vs surgery.

With medical management, the goal is to control the dog's clinical signs.  But the drugs don't do anything to stop the disease progression.  And, sometimes, the disease can progress very suddenly due to vascular or 'bruising' injuries to the spinal cord!  Othertimes, the progression is slow and due to progressive bony changes at the true joints in the vertebrae, the facets.

Thickening of the facets can often cause progressive signs in CCSM due to worsening spinal cord compression...

Surgery attempts to alleviate the compression and works with medical management to control the clinical signs but also to halt the progression of the disease.  In the ideal situation, surgical decompression even allows us to stop the medications.  

Unlike DAWS which can suffer a 'domino effect' following surgery, this isn't common with CCSM decompression.  But, just like DAWS, there are several surgical options for pets with CCSM.  Some include decompression by removing bone from the top and sides of the vertebral canal.  Others involve a distraction-fusion technique to allow the bone to resorb on its own and alleviate the compression.

Diagnosis of this disease often requires an MRI or a CT scan combined with a myelogram.  In the end, the diagnosis will play an integral role in deciding which medical or surgical option is right for each individual patient.

What is Intervertebral Disc Disease?

The intervertebral disc is a structure made up of two parts that sits between the bones of the spine, or vertebrae, and acts as a sort of 'shock absorber'.  The two parts of the disc are the anulus fibrosus, a ligament, and the nucleus pulposus, a jelly like substance.  The disc is, almost literally, formed like a jelly doughnut with the ligament on the outside and the jelly in the center.

Because the nucleus has a very high water content, it can't be compressed but, rather, any pressure placed on it is redistributed, evenly, around the interior of the ligamentous anulus fibrosus.  This is how it redistributes and diffuses compressive energy to act as a 'shock absorber'.

In some breeds of dogs, though, the nucleus pulposus isn't normal.  These dogs are called chondrodystrophic or hypochondroplastic.  Several breeds are predisposed to this condition and, therefore, to intervertebral disc disease.  This includes the dachshund, poodle, basset hound, and more.  When the nucleus pulposus degenerates in these animals it loses water content or 'dries out'.  After degeneration, the disc can no longer act as a shock absorber and so the ligament tears and the jelly, or nucleus pulposus, pushes out of the center of the disc and into the vertebral canal to cause compression of the spinal cord or the nerve roots.  This is also called a 'slipped disc'.

Intervertebral disc disease can be treated with medicine or with surgery.  Which option is best depends on several factors, but the prognosis for recovery is almost always much better with surgery.  In addition, there are procedures, called fenestrations, that we perform at surgery that lower the chances for another disc problem in the future.