Download August-Neurosurgical Cases: Diagnosis and Referral PDF

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Spinal Problems:
Spinal problems are central nervous system problems which arise due to
disease along the neuroaxis and effect long tracks and or alpha motor
neurons.
Neuroanatomy:
As a review – in higher mammals the long tracts originate in the brain cross
over and enter the spinal cord on the opposite side of the body. In lower
mammals these remain for the most part on the same side. This anatomic
principle allows veterinarians an added advantage when diagnosing spinal
disease.
When diagnosing the spinal patient we need to review basic neuroanatomy.
Suffice it to say this is the basic scheme neurologists utilize and it gets us
through many difficult situations.
Basically the right forebrain controls the left side of the body and vice versa.
The crossover occurs prior to the foramen magnum. Additionally, in lower
mammals the deep pain pathways follow the opposite path.
Schiff Sherrington - extended forelimbs and flexed rear limbs paralysis.
3ewDue to lesion L1-L7 spinal cord segments. Arises from Border cells
ascend up fasiculus proprious to inhibit extensor muscles.
Thus severe
lesion L1-L7 stiff forelimbs
Clinical Presentation:
When a patient presents the first thing I do is retrieve a good history from
the client. I use the word retrieve for obvious reasons. This is very helpful.
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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Next I determine the patient’s signalment (age, breed, sex). In neurology we
see many breed related conditions.
1. History - ask directed, open ended questions, reiterate in different
ways, ask specifically about behavioral changes, house training
problems, waxing/waning disease, pain, activity level, I always ask if
patient has been struck by an automobile, is he taking any
medications/herbs at this time
2. When did this start
3. When was the last time you saw patient walking?
4. Were all 4 limbs involved or only 1 or 2?
5. Has this happened before?
6. Has patient ever been sick before?
7. When was the last time the patient urinated and defecated?
8. Where do you feel the problem is?
There is some repetition of questions in order to get the correct answer
from the client. At times they hyperfocus on a problem and do not
reveal true disease progression.
Signalment - this information is very helpful to me
Neoplasia increases with age but it is still rare
Young patients seem to have more meningitis but it too is rare
Dachshunds almost always rupture disks followed by beagles,
cockers etc
Many small breed dogs have Chiari like malformation
Large breed dogs commonly have either cervical or
lumbosacral disease. And cervical disease can present as rear
limb weakness.
German Shepards usually have lumbosacral disease not
degenerative myelopathy. Many of these patients are very
stoic.
Brachycephalics and Goldens more prone to neoplasia
Note: For stoic patients or you are not sure about deep pain sensation,
have someone hold the patients head and gently pinch the forelimbs.
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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This should give you the information you need to assess the patient’s
ability to sense pain.
In large dogs it is difficult to differentiate a bad back, from bad hips
and bad knees however if the pelvis is elevated off of the ground and
proprioception is still slow there is a neurologic problem.
Physical Examination - TPR and weight don’t forget, abdominal
palpation masses on patient, cardiovascular disease how are pulses, pulse
deficits, metabolic disease (renal/hepatic), check toe nails for ware and
teeth for fractures luxation of the mandibular symphsis possible
trauma/automobile accident, lacerations, hemorrhage, ecchymosis,
petechiations, lungs clear, MM/CRT, hydration assessment, cervical
ventroflexion
Definitions: Paraparesis – weakness in rear limbs, Tetraparesis weak all
4 limbs Hemiparesis – weak on ½ of the body Paralysis no voluntary
movement in rear limbs – if patient is on side and moving limbs this is
paraparesis, Proprioception is the ability to know where the limb is in
space. ie high stepping gait, walking on dorsum of pes, standing on
dorsum of pes, circumducting limbs when walking, dragging toes
Neurologic Examination: don’t make a big deal about it
a. Is the patient mentally alert – keep it simple, seizures, stupor
(stoned) coma (cannot alert), painful. Note with spinal patients
mentation is either normal, excited or painful only (very few
exceptions) is patient paying attention to you if so most likely
brain is ok
b. Cranial nerves – Note copy of neurologic examination I use.
Basically, is there coughing, gagging, head tilt/turn, circling,
blindness, or a sided nature to the lesion.
For the remainder of this discussion we will assume mentation and
cranial nerves are normal that is to say the problem is caudal to the
foramen magnum
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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c. Can the patient walk this is a yes/no question – problem in all
limbs, just front limbs, just rear limbs, left side or right side of
body
NOTE: for orthopedic problems ie stifle and coxofemoral joint problems
the pelvis can be elevated with either the hand, knee or a helper in such a
way that the digits just touch the ground. If the patient can flip the foot
over there is no proprioceptive deficit if not there is a deficit.
d. Segmental Spinal Reflexes – key withdrawl all limbs, Extensor
carpi radialis, patellar, cranial tibial
Now we go to our patient model.
a. If weakness or proprioceptive deficits are in all 4 limbs then
the problem must be cranial to the T2 spinal cord segment or
is neuromuscular
b. If weakness or proprioceptive deficits are in the rear limbs
then the problem is caudal to the T2 spinal cord segment.
c. Now for reflexes
i. C1-C5 normal to hyper reflexes all limbs
ii. C6-T2 Decreased reflexes forelimbs, normal to
hyperreflexia rear limbs
iii. T3-L3 Normal reflexes forelimbs, normal to
increased reflexes rear limbs
iv. L4-S3 Normal reflexes forelimbs, decreased reflexes
rear limbs
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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Algorithim
Weakenss
Proprioception
All 4 limbs (Cranial T2)
Rear limbs (caudal T2)
-------------------------------------------------------------------------------------------
Spinal cord
Segments
C1-C5
C6-T2
T3-L3
L4-S3
Forelimbs
Rear limbs
Hyperreflexic
Hyporeflexic
Normal
Normal
Hyperreflexic
Hyperreflexic
Hyperreflexic
Hyporeflexic
Adjunct Testing
In order to assist in diagnosis and lesion localization I also use elicitable pain
occasionally. I define discomfort and pain in animals from severe
aggression to as mild as a change in respiratory pattern when a specific
portion of the body is manipulated. For the cervical spine there is cervical
ventroflexion, nerve root signature, and overt crying. The lumbar spine is
usually easy to assess, the lumbosacral joint commonly only elicits a change
in respiratory pattern.
Note: A technique to assess LS pain is to place the elevated pelvis on your
knee and push ventrally upon the LS joint this should take the coxofemoral,
stifle and hock joints out of the manipulation.
Patients with LS pain also have their tail clamped to their perineal region
and carry their pelvis flexed so that there is lumbosacral kyphosis
Notes:
1. Withdrawal is NOT sensation. A dachshund which is not walking but has
withdrawal, that does not try to bite when pliers are applied to the rear limbs,
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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most likely has either no sensation or the veterinarian is not being aggressive
enough. DEEP PAIN ASSESSMENT – the patient must have a physical,
conscious response minimally limited to consistently looking at or biting the
affected region which is being traumatized by the veterinarian present. .
Correct test is both dewclaws , lateral toes (digits1 and 5) and tail. Since
many patients have the dewclaws removed digit is acceptable to utilize
however not the best.
Crush each site with finger nails, then hemostats then pliers If the patient is
non ambulatory and is not trying to bite when force is applied with
deliberate strength to the skin and deep tissues of a region of the body this
patient has no deep pain sensation. This is of great concern since studies
based upon dachshunds show us that a 65% recovery rate to adequate
neurologic function occurs if surgery is completed within 36 hours with
patients when there is no deep pain response occurring to both rear
limbs and the tail. If there is any sensation then the prognosis is better
than this.
With forelimbs if there is no deep pain due to a cervical spinal cord lesion
most likely patient is near death if not dead. Note – rarely with PNS disease
this may occur.
Stage of Weakness Modified Frankel spinal cord injury scale
I.Spinal pain only
II.Ambulatory paraparesis
III. Non ambulatory paraparesis
IV. Non ambulatory paraplegia , has deep pain 90% recovery
with surgery
V. Non ambulatory paraplegic no deep pain 65% recovery with
decompressive surgery within 36 hours
When to Refer:
EMERGENCY: No deep pain, paralysis or severe paraparesis, rapid
decline in neurologic status. I prefer to see patient when the first start
having proprioceptive deficits. Paralysis with no deep pain (remember use
pliers) is an absolute emergency. Statistics based upon Dachshunds reveal
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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65 % recovery rate if the patient has surgery in 36 hours. After that time the
recovery rate drops off precipitously.
Referral to neurologist when :
Acute –chronic Stage III onward
Chronic –
1. Unrelenting pain
2. Waxing/waning disease
3. Progressive disease
When transporting patients, occasionally, tranquilization is required as is
pain management. If this needs to occur please use the medications
diligently. Remember it is very difficult to examine a patient that is
stuporous due to medications. Note: if transporting spinal fractures tape to a
board and sedate patient.
Patient Presentation to neurology:
History, physical, neurologic examination. The lesion is localized and a list
of rule outs given to the client. If we proceed I discuss risks associated with
procedures and that some patients will not get better. All patients have
blood work, urinalysis, thoracic radiographs. Imaging of the spine is either
myelography CAT scan or MRI. I use myelography for acute situations or
where I believe a single disk rupture is the problem. I use MRI when I
suspect multilevel disk extrusion, lumbosacral disease, cervical spine
disease, congenital defect or neoplasia. Once a diagnosis is made surgery is
decided upon or not. If surgery is recommended I usually attempt to have
this completed within 24 hours unless the patient has no deep pain then this
is right away.
Ancillary Diagnostics – electromyography, nerve conduction velocity
repetitive nerve stimulation, see peripheral neuromuscular disease.
Intervertebral Disk Disease
Hansen Type I acute rupture nucleus pulposus ruputures most common
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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Hansen Type II chronic annulus fibrosus protrudes into the canal large breed
dogs
Medical Management:
I prefer to reserve this only for patients with a single bout or so of moderate
pain or paraparesis. Anything more severe surgery is recommended.
Steriods are the mainstay of therapy. 4 years ago at ACVIM meeting a head
count revealed that over 50% of the neurologists do not feel that steroids
work. I do not necessarily take this view; however, I use them more
judiciously.
Steriod Dosages:
Prednisone 1 mg/lb
Dexamethazone 0.1 mg/lb
Pain Control:
Fentanly patches – I dose 1-2 ug/lb, 6-12 hour lag time duration of effect 72
hours
duration. Morphine as needed but if I am using a patch I give a
single dose until the fentanyl patch becomes effective
Tramadol – I dose 1-2 mg/lb tid for 2 weeks post surgery
Morphine see pharmacology text
Oxymorphone see pharmacology text
Hydromorphone see pharmacology text
Butorphanol see pharmacology text
Buprenorphine see pharmacology text
Steriods above
Tranquilization:
Acepromazine as needed see pharmacology text
Valium as needed may aid in micturition see pharmacology text
Phenobarbital – I wean from this over 1 month, additionally, this has added
pain control, I usually give 0.5 mg/lb
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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Confinement for 6-8 weeks
Surgical Management:
Note: It is no acceptable to complete neurosurgical decompression of the
spine without some advanced imaging ie myelography, CAT, MRI etc.
Survey radiographs are not adequate.
For emergencies, pain, moderate paraparesis to worse patient.
Hemilaminectomy – most common procedure I complete – for intervertebral
disk disease, neoplasia, acute, occasionally I will extend this to a
laminectomy, occasionally for cervical, most of the time thoracolumbar
region
Laminectomy (modified Funquist type II) – us in LS region, if spinal cord
swelling is present, for neoplasia, chronic disk extrusion, I also use this
procedure for extended dorsal laminectomies of the cervical spine, ie
Wobblers syndrome in large breed dogs.
Fractures I use Steinmann pins with methylmethacrylate externally, so the
implants can be removed. Commonly I also complete a laminectomy. Many
of these patients can also have external coaptation . It is imperative to be
several joints on either side of the fracture for adequate mobilization since
the spine is very flexible. Additionally, the neurologic examination
determines the prognosis for recovery with adjunct diagnostics assisting not
the other way around.
AA luxation, odontiodectomies I use a ventral approach with Steinmann
pins with methymethacylate and leave the implants in vivo, Note Dens
ossifies at 9-12 weeks of age and fuses 7-9 months of age. Alternatively a
dorsal approach with circlage wire can be completed. Finally, casting may
work 25% of the time.
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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Cervical ventral slot – I reserve this procedure for patients with single disk
ruptures with no impingement of the spinal canal dorsally. Occasionally, if
2 cervical disks are separated by a normal intervertebral disk I will complete
two slots.
General post operative management covered under rehabilitation care
Confinement 6-8 weeks
Rehabilitation
Fibrocartilagenous Embolization
These patient usually are active young adult dogs who either suffered
trauma, or a traumatic event jumping ect. There is acute onset of paraparesis
to paralysis commonly involving the intumescence ie segmental spinal
reflexes are decreased. This is usually sided ie hemiparesis and the patient is
either minimally or non painful.
Due to the severity of the disease I commonly complete diagnostics
immediately. However, if the patient is still partially ambulatory I may wait
24 hours to determine improvement especially if there are contraindications
to anesthesia or finances are a problem. I will give these patients steroids in
case this is a disk problem which will get better note steroids do not help
fibrocartilagenous emboli. If we can complete advanced diagnostics the
spinal cord is either normal or slightly swollen, csf is either normal or
slightly hemorrhagic. FCE patients have restricted activity but rehabilitation
with hydrotherapy is recommended right away.
Diskospondylitis
Bone infection along the endplates of the vertebral bodies occurs
occasionally in practice. These are usually large breed dogs who present
with paraspinal pain. Neurologic deficits are minimal to absent. Febrile
response is variable. Diagnosis is made many times on radiography.
Staph/strep most common isolates. If this disease is suspected in addition to
a work up blood cultures, urine cultures, and CSF cultures are completed. If
the patient has neurologic deficits the advanced imaging is completed and
surgical decompression with culture and histopath are completed. Antibiotic
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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therapy hopefully is based upon culture/sensitivity results but many times
these are nondescript. If so the antibiotic regimen should be maintained for
8-16 weeks. Commonly, I will treat until radiographic resolution occurs.
Recovery – Normal recovery for all spinal patients is strict cage confinement
for 6-8 weeks. I usually recommend 8 weeks. I want to see a minimum of
improvement every 8 weeks. I have had some patients walk after 6 months
and most patients improve for 1 year after these major diseases and
therapies. I do not tell the owners there will be no more improvement until 8
weeks with no change have gone by and a repeat neurologic examination has
been completed.
Bibliography:
1. Levine JM et al Association between various physical factors and
acute thoracolumbar intervertebral disk extrusion or protrusion in
Dachshunds. JAVMA Vol 229, No3 Aug 1, 2006, 370-375 longer
and taller doxyies more problems not associated with weight
2. Boothe DM Small animal clinical pharmacology and therapeutics.
WB Saunders 2001, USA pp 405-424
3. Slatter, Textbook of Small Animal Surgery, WB Saunders 1993 USA
1173-1237
4. Long term neurologic outcome os hemilaminectomy and disk
fenestration for the treatment of thoracolumbar intervertebral disk
herniation. 831 cases 2000 -2007 Aikawa et al JAVMA Dec 15,
2012 241 (12) 1617 – 26
Paraparetic paralysis with deep pain 97% recovery
No deep pain 52%
5. A retrospective study of ventral fenestration for disk diseases in dogs
Nakama S et al J Vet Med Sci 1993 Oct 55(5) 781-4
No deep pain recovery 65%
6. Small Animal Spinal Disorders diagnosis and surgery Sharp Wheeler
Mosby Philadelphia USA 2005
Ronald O. Schueler, D.V.M., L.L.C.
Diplomate ACVIM (Neurology)
Fresno Veterinary Specialty and Emergency Center
6606 North Blackstone Avenue
Fresno,CA 93710 ~ 559.451.0800
Veterinary Neurology and Rehabilitation
3132 Halter Road ~ Westminster, MD 21158 ~ 410.840.9559
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