Dr Larry Carpenter DVM MS

Diplomate, American College of Veterinary Surgeons

Veterinary Surgical Services

What is the role of the family practitioner in diagnosis and treatment of thoracolumbar or cervical IVDD in chondrodystrophic breeds?

Ideally the family practitioner and the referral surgeon are communicating freely and working together as a team to take care of the client and patient with IVDD to achieve the best outcome.  This works best if the family practitioner uses the surgeon as an extension of the general practice.  The family practitioner will almost always talk to the client and examine the patient first.  The accompanying Frequently Asked Questions about Disk Disease in Dogs can help the client to understand their dog’s problem and ways that we can help in their dog’s recovery.

The key decision that you and the client will make is how to treat the dog.  In some cases the need for surgery will be obvious (paralyzed dog that retains deep pain sensation).  In others, the circumstances of the case (other existing medical condition and owner financial constraints) will dictate that conservative therapy be initiated.  Surgery may be considered if/when the neurologic condition deteriorates. The advantages of surgery in general relate to the overall trend towards better outcome and the more rapid recovery (see attached chart comparing recovery in surgically treated dogs vs. those treated medically).   Reduction in the rate of recurrence can also be dramatic (4-10% following hemilaminectomy and fenestration of adjacent disk spaces) in surgical patients as compared to medically treated dogs.  The disadvantages are the cost of the myelogram and surgery and the invasive nature of treatment.  Conservative therapy has its advantages too – that is it is inexpensive and generally rewarding.  The disadvantage is that the dog’s condition may worsen in the short term and recurrence rates are fairly high (up to 34%) in the long term.   Conservative therapy is also labor intensive, takes time (up to 6 wks for healing of the annulus), requires strict adherence to the confinement regimen and works best with frequent communication with the client and rechecks of the patient.  Another disadvantage is that active rehabilitation of the patient must wait until healing of the annulus is well underway because the risk of making things worse is too great in the acute timeframe.  In contrast, rehabilitation can begin almost immediately in surgically treated patients.

Recently a consensus position on the treatment of IVDD was developed by veterinary neurosurgeons representing both the American College of Veterinary Surgeons and the Neurology subspecialty of the American College of Veterinary Internal Medicine (see the handout Standard of Care for Intervertebral Disk Disease:  Prognosis, Surgical Timing & Use of Glucocorticoids.  This document is a valuable guideline to your decision making in IVDD patients.

Some important information to gather at the time of presentation is listed below:

History is important:

            How long has the dog had a problem?  Is it a recurrence or first episode?

            How fast did the problem progress?  Immediate paralysis or sequential deterioration?

            Was one side more severely affected?  How affected & record which side?

            If the dog is down – how long?  Is the dog able to urinate?

            What home treatment (especially has aspirin been given)?

Exam findings:

            Degree of discomfort?  Spinal Hyperaesthesia – location?

            Neurological deficits?  What and where?  One side worse than the other?

            Be sure to distinguish deep pain sensation from withdrawal reflex

            Deep pain absent?  For how long?

            Grade the IVDD according to the scale:

                        Grade 1 – Pain

                        Grade 2 – Weak but able to walk

                        Grade 3 – Weak, unable to walk

                        Grade 4 – Paralysis (usually accompanied by loss of bladder function)

                        Grade 5 – Complete loss of feeling

*(loss of bladder and bowel control can occur as early as grade 3 or as late as grade 4)

Survey X-ray findings (ACVR specialists can tell the right space only 66% of the time):

            May be normal

            Mineralized disks (if the disk is in the normal location it is usually not the one)

            Disk space narrowing (need view centered over the disk space to be sure)

            Wedging of the ventral disk space

            Overlapping of the facet joints

Treatment:

            In-patient or out-patient?

            Conservative vs. surgical

Referral?  - Grade 2’s and higher are surgical candidates (see standards of care).

Do’s & Don’ts for IVDD

Do’s

1)      Do Discuss lifestyle changes that may help to minimize recurrence – limit stairs, jumping, agility training etc & initiate weight control

2)      Do Discuss conservative vs. surgical therapy.  See #3 under Don’ts below

3)      Do Determine to the best of your ability what neurological grade the dog fits into and record the exam findings that you base that determination on.

4)      Do Become familiar with the ACVS/ACVIM Standard of Care for Intervertebral Disk Disease and use it in your practice.

5)       Do Discuss cost of myelogram, surgery and after-care before referring the client.  In our hospital we quote $2500 – $3000 for myelography, surgery, and hospital care depending on length of hospital stay.  We encourage clients to use CareCredit as a method of making payments.

6)      Do Call us and speak to the surgeon to facilitate the referral process.

Don’ts

1)      Don’t Confuse the withdrawal reflex for central recognition of pain.  Withdrawal is the unconscious pulling away of the leg that is mediated through a reflex of the femoral and sciatic nerves at the lower lumbar spine and does not require awareness by the dog.  Central recognition of pain is characterized by brain activity and active intervention by the dog; that is vocalization, attempts to bite and turning towards the side that is being pinched.  This implies neurologic continuity from the foot to the brain. You may have to place the lock boxes of a hemostat over the digit and squeeze to determine if deep pain perception is present.

2)      Don’t Anesthetize the patient to take x-rays unless you are prepared to do a myelogram and surgery at your practice.  The patient’s primary defense against further disk extrusion is dependent upon adequate control over the trunk muscles – this defense is eliminated with anesthesia.  Also if you are going to refer the dog, anesthesia (or even sedation) will likely cause confusion as to the animal’s responses later that day when the surgeon completes the neurologic exam.  If the dog is being referred, our first step during the myelogram is to obtain properly positioned and technically high quality survey films.

3)      Don’t Administer or prescribe analgesics or steroids without assuring that the owner understands and is committed to adequate confinement of the dog (minimum 2-4 weeks of cage confinement, preferably 6 wks).  Confinement to a bathroom is not adequate (slippery floors and too much space).  Also discuss that when the dog starts to feel better, he still needs to be confined to prevent further extrusion of the disk and sudden relapse with potential for profound worsening of neurologic status.

4)      Don’t Handle all clients and patients the same way.  Some clients want conservative therapy only, others want early referral and consultation. 

5)      Don’t Treat an animal conservatively all week long and refer on Friday afternoon if not improved.

6)      Don’t Tell the client to make a routine appointment for a myelogram and surgery – please call us to arrange the most expeditious referral process.  We handle these cases as soon as possible, and will give the procedure priority over elective procedures – PLEASE NOTE – WE ARE UNABLE TO OFFER SURGERY ON WEEKENDS OR HOLIDAYS.