neuro CL articles

Question 1

de Decker S, Gielen IMVL, Duchateau L, Oevermann A, Polis I, van Soens I, et al. Evolution of clinical signs and predictors of outcome after conservative medical treatment for disk-associated cervical spondylomyelopathy in dogs. J Am Vet Med Assoc. 2012 Apr 1;240(7):848–57.

Answer 1

• 21 dogs, DAWS cases only again – now they are calling it “DA-CSM”
  
  • 38 % success
  • degree of compression seemed to have some correlation with outcome, but the measurements have previously been shown to not have great interrator reliability so DeDecker doesn’t recommend them
  • how dogs were doing at one month predicted whether medical management would be successful
  • the “domino effect” after sx might just be the natural progression of dz – one of these dogs had similar

Question 2

De Decker S, De Risio L, Lowrie M, Mauler D, Beltran E, Giedja A, et al. Cervical Vertebral Stenosis Associated with a Vertebral Arch Anomaly in the Basset Hound. J Vet Intern Med. 2012 Sep 14;26(6):1374–82.

Answer 2

• novel vertebral malformation in Bassetts characterized by:
  - smooth hypertrophy of >1 adjacent vertebral lamina & spinous processes
  
  • 18 Bassetts, most

Question 3

Beltran E, Dennis R, Doyle V, De Stefani A, Holloway A, De Risio L. Clinical and magnetic resonance imaging features of canine compressive cervical myelopathy with suspected hydrated nucleus pulposus extrusion. Journal of Small Animal Practice. 2012 Jan 17;53(2):101–7.

Answer 3

• first report of “hydrated nucleus pulposis extrusion” in the neck
• “HNPE” differs from “ANNPE” in that it is compressive. A 4th type of IVDD?
• “seagull sign” on transverse images
• lg and sm dogs, 8-13 years old, 7 had V-slot, 9/10 dogs did well
• discal cyst is a differential

Question 4

Ligaments and attachments of the AA jt - 5 of them

Answer 4

Transverse (spans canal within (atlas?)
Apical: dens to foramen magnum
Alar (bilateral): dens to occipital condyles
Dorsal atlantoaxial: dorsal arch of atlas to cranial dorsal spine of axis

Question 5

Congenital or developmental anomalies of the atlantoaxial joint

Answer 5

Hypo or A plasia (46%)
Dysplasia (34% of dogs)
Dorsal angulation and separation of the dens
Absence of the transverse ligament
Incomplete ossification of the atlas
Presence of block vertebrae (fusion of two or more)

Question 6

What % of dogs with AA sublux is estimated to have a normal dens

Answer 6

24%

Question 7

If taking sedated or anesthetized x-rays on a dog you suspect may have AA instability how should you hold the head and neck?

Answer 7

Slightly extended

Question 8

The contraindication for dorsal stabilization of AA subluxation

Answer 8

Dorsal deviation of the dens

Question 9

Modified ventral approach to cervical vertebrae
Benefit
Who reported it?

Answer 9

Separate the RIGHT sternocephalicus mm from the paired rt sternoHYoideus/thyroideus mm and use the RIGHT sternohy/thyroideus to retract the trachea, esophagus, vagosymp trunk, rt recurrent laryngeal n. and cartoid sheath to the LEFT. The sternocephalicus is retracted to the left
It helps protect named structures
Shores etal VetSurg 2007

Question 10

What are the 3 big categories of neuron damage?

And the 5 classifications mentioned in Tobias

Answer 10

Neurapraxia (class I), axonotmesis (II), neurotmesis (III - V)

Question 11

What is class 1 nerve damage (per Tobias) also known as and describe it

Answer 11

Nerurapraxia = Interruption of function and conduction of a nerve without structural change.
Reversible - may take hours to 6 days

Question 12

What is class 2 nerve damage (per Tobias) also known as and describe it

Answer 12

Axonotmesis = Structural change occurs, however, internal structures (endoneurium and Schwann sheath) is fairly well preserved. Wallerian degeneration occurs in distal stump.
Recovery usually good (in order of weeks)

Question 13

What are classes 3-5 nerve damage (per Tobias) also known and describe it

Answer 13

Neruotmesis =
3 - Disruption of axons and endoneurium, but perineurium is intact so fasicular orientation is preserved.
4- Perineurium is included in disruption
5- Peripheral n is severed

Question 14

AA sublux prognosis (medical mgt)

Answer 14

Good long term ~38% (10 of 26)
those affected less than 30d did best
Recurrence or progressive decline

Question 15

AA sublux prognosis surgical = Dorsal vs Ventral

Incidence of implant failure?

Answer 15

61% dorsal good to excellent when all techniques considered
47% - 92% ventral, depending on technique.
Implant failure 44% ventral, 48% dorsal

Question 16

Pike FS et al. Reduction and Fixation of Cranial Cervical Fracture/Luxations using Screws and Polymethylmethacrylate (PMMA) Cement: A Distraction Technique Applied to the Base of the Skull in Thirteen Dogs. Vet Surg. 2012 feb.

Answer 16

• used gelpi in dogs 8 kgs
• 9 dogs with traumatic C2 fracture, 4 dogs with AA luxation
• good outcome in these dogs with their distraction technique. Basion - ventral edge of foamen mag
  
  • reported mortality for cervical fractures = 32%. 10% for fractures here
  • complications in this study:
    
    • overdistraction (no clinical problems)
    • screw break (no clinical problems)
    • death (2 dogs)
    • disk space collapse at the caudal anchor point (almost all dogs)

Question 17

Where is cervical IVDD most common in chondrodystrophic dogs?
Large breed dogs?

Answer 17

44-59% at C2-C3 alone
80% affect spaces C2-C4
Large breed - C6-C7

Question 18

in 53 dogs presenting for cervical pain only, what % had myelographic evidence of disk extrusion/protrusion? And what % had evidence of moderate to severe spinal cord deviation?

Answer 18

94% and 60%

Question 19

True or false - MRI is the best method for evaluation of the surgical spinal cord and through use of the degree of spinal cord compression can be used for post surgical prognosis

Answer 19

False.

Question 20

How big is your slot?

Answer 20

Slot width and length should be kept to about 1/3 those of the vertebral body. But with respect to width you can get close to but should not extend beyond 1/2.

Question 21

What weight limit does Tobias recommend for fenestration in the cervical region

Answer 21

30kg

Question 22

Tobias reports overall incidence of death attributable to hypoventilation in dogs w cervical spinal disorders

Answer 22

1.8-3.5%

Question 23

According to Tobias what factors have been associated with outcome in cervical IVDD

Answer 23

Site? May have poorer prognosis with more caudal (caudal to C4) but may be confounded by wobblers dogs
Type of tx = yes. 49% med vs 90% 1 month-98% 12 months successful sx
Response to tx = yes. Not walking by 2 weeks aint good
Degree of neuro injury/deficit - Not shown to be significant
Duration of clinical signs - No

Question 24

What vascular structures are in the transverse foramen of the atlas?
The lateral vertebral foramen?

Answer 24

The vertebral vv and aa pass through the transverse foramen. The later on its way to pass through the lateral vertebral foramen to access the vertebral canal

Question 25

Outcomes of medical and surgical management of cervical IVDD according to Tobias

Answer 25

49% successful outcome med w 18% failure and 33% recurrence
90% 1 month-98% 12 months complete recovery w sx and ~5-10% recurrence in ~91 days
66% success in large breeds and caudal cervical - but may have needed stabilization and didn’t get it

Question 26

Briefly describe the 3 types of brachial plexus trauma (avulsion)

Answer 26

1) cranial avulsion, rare. Can bear weight
2) caudal avulsion, more commmon. Radial nn involved so non wt bearing, but other nns ok so hold limb flexed and many will have partial corners
3) Complete, also common. most severe, drags leg, knuckles, muscle atrophy noted ~7 days

Question 27

Forterre F, Vizcaino Revés N, Stahl C, Gendron K, Spreng D. An indirect reduction technique for ventral stabilization of atlantoaxial instability in miniature breed dogs. Vet Comp Orthop Traumatol. 2012 Jul 12;25(4):332–6.

Answer 27

• a new reduction technique described to hold AA joint in reduction during ventral surgery
  
  • Gelpi in intercondyloid incisure (cranial) and in vertebral body of C3 (caudal) to distract
  • orthogonal Gelpi in longus colli muscle can be used to reduce

Question 28

What is nerve root signature?

What % of dogs with cervical disc disease does tobias say in can be seen in

Answer 28

Compression of a cervical nerve root. Present as TL lameness
Can be seen in 22-50% of dogs with cervical IVDD