What is the Treatment for Chiari-like Malformation (COMS)?

I often describe the disease process involved in these cases using the analogy of putting your finger over the end of a garden hose.  When you do, the same volume of water comes through as it did without your finger in place, but the aperture is much smaller.  This causes changes in the hydrostatic pressure of the flow through the end of the garden hose.  

With every heartbeat, there is a sudden surge of fluid through the hole at the base of the skull.  This allows the skull to accommodate the increased volume of blood that comes in with every heartbeat. But the change in pressure that happens with the cerebellum herniated (or just crowded) at the base of the skull is just like having your thumb over the end of the garden hose ...

This is a video of a special MRI sequence performed in a human that shows the pulsatile flow of spinal fluid caused by the heartbeat ...

Management of this condition with medications (like prednisone and omeprazole) attempts to reduce the production of spinal fluid.  This is analogous to turning down the spigot while keeping your thumb over the end of the garden hose ...

Surgery removes the compression on the cerebellum to allow the fluid to pass through more easily.  This is akin to taking your thumb off the garden hose ...

I mention all of this, because I want to remind everyone that surgery doesn't directly make the syringohydromyelia (SM) in the spinal cord go away.  Rather, it prevents the disease from getting worse by removing the underlying cause.  That's important because it plays into how we define 'success' when looking at surgery.

I always caution my clients to think of a successful surgery as - a patient that recovers from the procedure with no complications and does not get worse over time due to progression of the SM.  In other words, these patients may still require medications and the surgery does not (necessarily) make the SM go away.  If we get improvement beyond this definition of success, then I call that 'icing on the cake'.  Using this definition of success, we are successful with surgery more than 80% of the time.  

Most of the surgical failures happen months to years after the procedure due to scar formation at the surgical site.  This seems to be where the titanium mesh has its greatest benefit.  Since I've been using the mesh, I haven't had any patients worsen in that time frame.  

Also, when we remove the bone, there is still a thick membrane (the meninges and particularly the dura mater) that restricts and confines the cerebellum and brain.  By patching in a piece of tissue, we can make more room within this membrane and relieve the compression.  It's very similar to letting out the waist in a pair of pants.  To help prevent scar tissue from forming here and undoing all that we've done, I use tissue collected from the patient's themselves (autograft) rather than material that might cause more inflammation or rejection of the graft.

Brain tumors in dogs and cats

Dogs and cats can develop brain tumors similar to those found in people.  These tumors can cause a variety of clinical signs depending on where they are and what structures are affected.  Diagnosis often requires an MRI of the brain and sometimes we use spinal fluid tests as well.

Just because a dog or cat has a brain tumor, it doesn't mean that they can't be treated.  While some cancers are treated with chemotherapy, we have surgical options for some others.  The overall prognosis will depend on what type of tumor it is, where it is, and what treatment option is chosen.

Chemotherapy in animals is not very similar to what happens in people.  Because of the doses and drugs that we use, dogs and cats very rarely have significant side effects from the medications.  After all, our goal is ALWAYS to maintain your pet's quality of life for as long as we possibly can.

We've recently added a new device to our surgical suite that allows us to more readily and completely remove cancer cells at surgery.  It's called a Cavitronic Ultrasonic Aspirator, or CUSA.  This device uses ultrasound waves to disrupt the adhesions between the cancer cells which literally liquifies the tumor.  It then irrigates the area with saline and aspirates the cancer cells back out!

At LOVN we are skilled and experienced in all of the surgical approaches to the brain.  We have the technology and expertise to give your pet the very best care and outcome.  A recent case that we performed a transfrontal craniotomy on (see the illustration above) allowed us to use the CUSA for surgical removal of her meningioma.  With this device we are able to get so much of the tumor that we expect her to be disease free for close to two years!

What is Wobbler's Disease?

Wobbler's disease is a term used to describe two different pathological processes in the neck of dogs.  One form happens in younger large breed dogs, and the Great Dane and Mastiff are the most common breeds.  The other form happens in older dogs, and the Doberman Pinscher is the most common breed.  It also occurs in horses, but we'll save that for another blog post on another day!  

The medical term for the condition in younger dogs is Caudal Cervical Spondylomyelopathy.  In this disease, the spinal cord is compressed by increased thickness of the bones in the vertebrae themselves.  Typically, this is towards the base of the neck, and it is slowly progressive.  While low doses of steroids can help control the disease; this type of medical management does not address the underlying cause and the signs often progress in spite of the drugs.  Surgery to remove the compressive bone is often curative but is a complicated procedure and carries some degree of risk.

In older dogs, Wobbler's disease is more aptly termed Disc Associated Wobbler's Syndrome, or DAWS.  In these patients the spinal cord compression is caused by bulging of the intervertebral disc and thickening of other supportive ligaments in the vertebrae at the base of the neck.  Medical management for this condition also makes use of low-dose steroids.  Just like the condition in younger dogs though, medications do not treat the underlying cause and the clinical signs often progress.  Surgical options exist for these pets as well, but have often been plagued with complications.  Particularly, a problem known as the 'Domino Effect'.  We'll discuss this condition and the surgical options in more detail in a later post.

Because both of these conditions occur in the neck and are progressive, dogs can become completely paralyzed if not treated.  Classically, these pets have a 'two-engine' gait where the forelimbs take short and choppy strides and the hindlimbs have a longer, loping gait.  

If you think your pet might have Wobbler's disease, contact your veterinarian.  Oftentimes an MRI is necessary to make the diagnosis, but there are treatment options and help is out there!

This is a video illustrating the gait disturbance we typically see and outlining the story of a dog with Wobbler's Disease that had a disc replacement surgery!  If you're interested in learning more about disc replacement therapy and the Adamo Spinal Disc click here.

What is a Veterinary Neurosurgeon?

There are a few Veterinary Neurologists that only treat conditions requiring medical management, but the vast majority of us now also perform neurosurgery.  In veterinary medicine, there is no such thing as a 'Board-Certified Veterinary Neurosurgeon'.  Which is why some primary care veterinarians and some Veterinary Surgeons perform limited neurosurgical procedures.  

My residency at UC Davis was in Neurology and Neurosurgery and I was part of the charter group to gain the Advanced Training in Veterinary Neurosurgery Certificate.  I am also a member of the Veterinary Neurosurgical Society.  And, most recently, I attended a certification course to be one of a small group of veterinarians, world-wide, that are able to provide disc-replacement surgery for dogs.

So, as you can see, I have a very strong interest in neurosurgery!  I've done all that I can to make sure that LOVN is able to offer the very best cutting-edge neurosurgical techniques.  I've also got the experience and the amazing staff to be able to offer the very best in neurosurgical outcomes.

In fact, we've recently acquired a new device that will enhance our neurosurgical capabilities even farther!  It's called a Cavitronic Ultrasonic Surgical Aspirator (CUSA) and it's awesome!  That's going to be a blog post all on it's own!