Week 5 Pt. 2 (Cervical/Thoracolumbar Neurosurgery)

Brain disease can look similar to what other disease processes?

- Cervical spinal disease

What are clinical signs of brain disease?

- Mentation changes

- Seizures Headaches

- Hemi-neglect (Can still see on one side, but not processing the info)

- Big circles

- Hemi or tetra ataxia

- Hemi or tetra paresis

- Stiff neck

- VERTICAL nystagmus

What are the most common surgical diseases of the brain?

- Tumors

- Hydrocephalus

- Chiari- like syndrome

- Maxillary/ Zygoma Skull Fractures

What are some potential neurologic exam findings for spinal segments C1-C5?

- +/- stiff or painful neck, +/- spontaneous screaming

- Tetra-ataxia

- Ambulatory or non ambulatory tetraparesis

- Tetraplegia is rarely possible =respiratory paralysis= death

- Muscle tone normal or increased

- Myotactic reflexes intact or UMN in all 4 limbs

- Withdrawal reflexes intact in all 4 limbs

- Upper motor neuron bladder and anal sphincter

What are some potential neurologic exam findings for spinal segments C6-T2?

- +/- stiff or painful neck, +/- spontaneous screaming

- Thoracic limb lameness/weakness or nerve root signature lameness (Shoot pain down neck into limb)

- Tetra-ataxia (often worse in hind limbs)

- Ambulatory or non-ambulatory tetraparesis

- Tetraplegia is rarely possible = Respiratory paralysis = Death

- Muscle tone may be decreased in front legs, and normal or increased in back legs

- Myotactic reflexes decreased in front limbs

- Myotactic reflexes intact or UMN in hind limbs

- Withdrwawal reflexes decreased in front limbs, intact in hind limbs

- UMN bladder and anal sphincter

What are some surgical C1-C5 Ddx?

1. Hansen's Type 1 (chondroid) Disk Disease

2. Wobblers (disk or osseous associated)

3. Atlantoaxial subluxation/ luxation

4. Spinal Tumor

5. Trauma (fractures, luxations, hematoma,

- Cats: Trauma, bb air-gun pellets, falls, etc.

What are some medical C1-C5 Ddx?

- Autoimmune meningitis: Granulomatous meningoencephalomyelitis, Steroid Responsive Meningitis, Pug Dog Meningitis

- Inflammatory/ infectious

- Fibrocartilaginous Embolism

- Syringohydromyelia (fluid in the spinal cord) itself)

- Discospondylitis

- CATS: Lymphoma and Feline Infectious Peritonitis

What are some surgical C6-T2 Ddx?

1) Wobblers (disk or osseous associated)

2) Hansens Type 1 (chondroid) Disk Disease

3) Spinal Tumor- NERVE SHEATH TUMOR

4) Trauma (fractures, luxations, hematoma, gunshot)

- Cats: Trauma, bb air-gun pellets, falls, etc.

What are some medical C6-T2 Ddx?

- Autoimmune meningitis: Granulomatous meningoencephalomyelitis, Steroid Responsive Meningitis, Pug Dog Meningitis

- Inflammatory/ infectious

- Fibrocartilaginous Embolism

- Syringohydromyelia (fluid in the spinal cord) itself)

- Discospondylitis

- CATS: Lymphoma and Feline Infectious Peritonitis

Paralysis of all 4 limbs = paralysis of ____________.

- Breathing

What are early signs of respiratory paralysis?

- Abdominal breathing patterns

- Panting

- Decreased ribcage excursions

The cervical spinal canal has more space relative to size of the spinal cord for mobility. What does this mean for pathology?

- By the time there is neurologic deficits = Severe compression

- Any deficits localized to cervical spinal cord -> Emergency

What is the pathogenesis of AA luxation?

- Hypoplastic dens/stabilizing ligaments of the atlantoaxial joint

What animals are commonly affected by AA luxation?

- Toy breed dogs

Describe the typical clinical presentation of AA luxation.

- Low head carriage

- Tetra paresis and tetra ataxia in all four legs

- Inability to stand or move the legs

- Difficulty breathing

What dogs with AA have a better prognosis?

- Dogs with shorter duration of signs

How is AA repaired?

- Screws and PMMA cement work best

What are some complications of AA repair?

- Breathing difficult

- Pneumonia

- Implant migration

- Collapsing trachea

- Hemorrhage (Blood vessels running through vertebrae)

Dogs with untreated AA die from...

- Can get kinking and edema of brain stem -> Death

What animals are commonly affected by cervical IVDD?

- Small breed dogs

- Chondrodystrophoid dogs

- Beagles, Whippets and French bulldogs; Labs, Dalmations

How do patients with cervical IVDD present?

- 50% present with acute signs

- 50% present with slow onset, chronic signs

What are some clinical signs associated with cervical IVDD?

- Severe and unrelenting neck pain and unable to move neck (90% pts)

- Nerve root signature lameness (25-50%) - Weakness or paralysis in the limb innervated by the pinched nerve root

- Ambulatory tetraparetic (42%); Very bad -> Next stop is respiratory paralysis

How is cervical IVDD diagnosed?

- Radiographs (35% accurate)

- CT (small breed dogs, often have mineralized disk which can be seen on CT)

- MRI (large breed dogs - Don't have mineralized discs)

How can cervical IVDD be managed medically?

- Strict cage rest x 4-6 weeks

- NSAIDS or steroids, Gabapentin, fentanyl patch, codeine

- Muscle relaxants: methocarbamol

When can medical management be attempted for cervical IVDD?

- Mild to moderate pain only

- No neurologic deficits

In what cases of cervical IVDD is advanced imaging and surgery essential to recommend?

- Severe unrelenting pain

- In more comfortable patients, if pain does not diminish with meds and rest

- Any neurologic deficits

According to the ACVIM, in what cases are steroids indicated for cervical IVDD?

- Corticosteroids are not recommended for routine use in medical management of the acute phase of presumptive TL-IVDE

- In the chronic phase, a short course of anti-inflammatory doses of corticosteroids may be of benefit for some dogs

What approach is used for surgical repair of cervical IVDD?

- Ventral slot

What are indications for a ventral slot surgery?

- Decompression of Hansen's type 1 disk disease

- Disk associated Wobblers -> Do in combination with fusion surgery

What are some structures encountered on the approach for a ventral slot surgery?

- Trachea

- Esophagus

- Vagosympathetic trunk

- Carotid

- Recurrent laryngeal nerve -> Laryngeal paralysis, disphonation

- Sympathetic nerve branch to eye -> Horners

- Other small nerve branches involved with pharyngeal sensation and motor function

What post-op care is needed for ventral slot surgeries?

- Strict cage rest x 8 weeks

- NSAIDS, Gabapentin, fentanyl patch, codeine

- Muscle relaxants: methocarbamol

- Icing

- Physical therapy

What are some potential complications for a ventral slot surgery?

- Bleeding

- Respiratory paralysis (Injury to recurrent laryngeal nerve or spinal cord edema affected brainstem/respiratory centers)

- Laryngeal paralysis

- Arrhythmias

- Residual disk

- Horner's Syndrome

- Spinal Subluxation

- Pneumonia

- Neurologic deterioration despite best efforts (chronic cases)

True or false: Patients with cervical IVDD (Type 1) and caudal cervical spondylomyelopathy present very similarly.

- False; Wobblers presents with more chronic signs and mild ataxia (Only ~15% present for pain)

What are the two flavors of Wobblers?

1) Osseous associated

2) Disc associated

Describe the pathogenesis of osseous associated wobblers.

- Spinal canal is more square/rectangular in shape or even hourglass -> Lateral aspect of spinal cord is pinched -> Ataxia

- As patients age, they start getting facet OA -> Dorsolateral pressure on spinal cord -> Proprioceptive tract pressure -> More ataxia

Describe the pathogenesis of disc associated wobblers.

- Instability of caudal cervical vertebrae and Disc starts to bulge (chicken and the egg with past two) -> Vertebrae subluxate past each other as patient move -> Frequent micropressure on disc -> Disc bulging -> Spinal cord compression -> Ataxia

How is wobbler's treated?

1) Osseous associated -> Dorsal laminectomy +/- fusion

2) Disc associated -> Ventral slot + distraction + fusion; disc arthroplasty

What are possible complications of surgical correction of Wobblers?

- Domino effect

- Neurologic deterioration

- Implant failure

- Laminectomy membrane

- Foraminal collapse

- Pneumonia

- Insufficient decompression (large dogs)

What is the prognosis of Wobblers with surgical correction?

- 80% good prognosis with 25% reoccurrence

What post-op nursing care is needed for cervical spine patients?

- The more severely affected the more intense the nursing care

- Ventilator support

- Decubitus ulcers (toes, hips, elbows) -> Padding and recumbency change

- Urinary retention -> Ucath

Why are cervical spine patients prone to atelectasis and pneumonia?

- Can't cough or sigh

Which type of fibers are most susceptible to damage?

- Superficial, larger, and myelinated fibers

What are some potential neurologic exam findings for a lesion between T3 and L3?

- +/- stiff or painful back- can look like abdominal pain

- Normal forelimbs (Except if Schiff-Sherington posture for cranial lumbar lesions)

- Para-ataxia

- Ambulatory or non-ambulatory paraparesis

- Paraplegic

- Muscle tone to hind limbs normal or increased

- Myotactic reflexes intact or UMN in hind limbs

- Withdrawal reflexes intact or exaggerated in hind limbs

- UMN Bladder: Can't pass urine due to spastic sphincters

- UMN anal sphincter: Formed stool with intermittent solid fecal balls falling out

What are some potential neurologic exam findings for a lesion between L4 and S2/3?

- Hunched/ flexed rump/ +/-painful tail jack+/- stiff or painful lumbar spine, +/- nerve root signature lameness

- Normal forelimbs

- Para-ataxia

- Ambulatory or non-ambulatory paraparesis

- Paraplegic

- Muscle tone to hind limbs decreased to absent, flacid

- Myotactic reflexes decreased to absent

- Withdrawal reflexes decreased/incomplete toe or hock flexion/absent

- LMN bladder (flaccid/leaking/difficult to express)

- LMN anal sphincter (open/no wink/leaking liquid feces)

What is the most likely cause of thoracolumbar spinal disease?

- Degenerative Diseases (IVDD if over 1 YO, degenerative instability/stenoses, degenerative myelopathy)

What are some non-surgical DDx for thoracolumbar spinal disease?

- FCE (large breed dogs)

- Auto-immune meningits (small breed dogs)

What are the goals of neurologic surgery?

- Decompression CNS

- Maintain or return stability/bony protection of CNS

- Relieve pain

- Allow CNS to heal if possible

For every day a patient is down in the rear prior to surgery equates to how long being down post-op?

- 1 day prior = 1 week post-op

With thoracolumbar disease, one expects _________ signs to the hind limbs. Will the bladder be expressable?

- UMN

- Difficult to express bladder because sphincter cannot relax (May be able to elicit detrusor reflex if meds are on board)

Will a patient with thoracolumbar disease be fecally incontinent?

- Expect UMN fecal incontinence (abdominal press may cause a poop to fall out)

What are some common surgical Ddx for thoracolumbar disease?

1) Hansen's Type 1 (chondroid) DIsk Disease

2) Trauma (Fractures, luxations, hematoma, gunshot)

3) Congenital deformity

- Cats: Trauma: Bb air gun, pelletes, falls, disks

What are some common medical Ddx for thoracolumbar disease?

- Hansens Type 2 Disk Disease

- Fibrocartilaginous Embolism

- Degenerative myelopathy

- Spinal tumor

- Congenital deformity

- Discospondylitis

- Autoimmune meningitis: Granulomatous meningoencephalomyelitis, Steroid Responsive Meningitis, Pug Dog Meningitis

- Inflammatory/ infectious

Syringohydromyelia (fluid in the spinal cord itself)

- CATS: Lymphoma and Feline Infectious Peritonitis

What is the typical function of the nucleus pulposus?

- Handles disk compressive forces

Describe the pathophysiology of Hansen Type 1 IVDD.

- "pew pew" - Dr. Ihms

- The disc degenerates due to FGF4 retrogene insertion (in chondrodystrophic breeds) which results in dysplastic, shortened long bones and premature degeneration/calcification of the IVD nucleus pulposus

- Dehydrated, chunky nucleus can't handle normal compressive forces and it can explosively rupture with the slightest provocation

What are some chrondrodystrophic breeds?

- Dachshund

- Pekingese

- Corgi

- Beagle

- Lhasa apso

- Mini poodle

- Maltese

- Chihuahua

IVDD is most common at which intervertebral disc spaces in chondrodystrophic breeds?

- T12-13 through L1-2 most common (Keystone in the spinal arch under the most compression)

Which non-chondrodystrophic breeds are predisposed to Hansen type 1 IVDD?

- Dobermans

- Labradors

- Tollers

IVDD is most common at which intervertebral disc spaces in non-chondrodystrophic breeds?

- L1 to L2

What is the typical age of onset for type I hansen IVDD?

- Chrondrodystrophic breeds: Age 1-10 years, peaks at 3-6 years of age

- Non-chondrodystrophic breeds: Age 6-8 years

Onset of signs associated with type I IVDD are usually ____________.

- Sudden (can progress rapidly)

If a patient presents w/o neurologic deficits, but with back pain upon spinal palpation, what should you do?

Offer referral, if owners decline:

- STRICT CAGE REST x 4 WEEKS

- NSAIDS (Steroids prevent Glu from getting into cells and inhibit protein synthesis - not good for this)

- GABApentin (pregabalin is better)

- Opioid

- +/- methocarbamol

- OFFER OVERNIGHT STAY FOR OBSERVATION, PAIN MEDS, IV FLUIDS

If owners decline all this -> Recheck exam in 24 hours and check in with O at end of day

- Make sure O is educated that they could wake up the next AM to a paralyzed pet and this could turn into a surgical ER at any time

When a patient presents with neurologic deficits and back pain upon spinal palpation, what should you do?

- Referal ASAP for advanced imaging and surgery

- Diagnosis: CT, MRI, (Myelogram - no longer standard of care)

What are indications for surgery in cases of Type I IVDD?

- Persistent pain (even without neuro deficits) despite rest and meds

- Cervical cases with ANY neuro deficits -> ER

- Large disk ruptures causing cord compression on advanced imaging

- Neurologic deficits, especially motor deficits (Once a pt starts losing motor or pain sensation, surgical decompression is needed ASAP)

What surgery is performed for decompression of IVDD in the thoracolumbar region?

- Hemilaminectomy

What is the prognosis for hemilaminectomies?

- As long as deep pain sensation is present, 85-97% of cases will make a complete recovery