31 - IVDD

Question 1

where is the thickness of the intervertebral dice greatest?

Answer 1

cervical and lumbar regions

Question 2

which cervical spaces are widest

Answer 2

C4 C5, C5 C6

Question 3

where is the dorsal longitudinal ligament thickest (region of spine) and what does it prevenet

Answer 3

cervical spine, provides resistance against dorsal herniation f nucleus pulposus.

Question 4

what percentage of IVDD occurs in the cervical spine?

Answer 4

14-25%

Question 5

which breeds are prediposed

Answer 5

chondrodystrophic and toy breed

Question 6

In large breed dogs what should always be considered alongside IVDD for cervical localisaigon

Answer 6

Cervical spondylomyelopathy

Question 7

is IVDD occurring most commonly in cranial or caudal cervical spine

Answer 7

cranial, 80% affect C2 - C4

Question 8

what can typically good recoveries of hydrated nucleus purposes extrusion be put down to?

Answer 8

jelly like structure causing minimal compression

Question 9

90% of dogs presenting w cervical pain had disc protrusion or extrusion, only 60% had spinal cord compression, why?

Answer 9

ratio or vertebral canal diameter to SC diameter is large, sc can be displaced without compression.

Question 10

nerve root signature is present in how many dogs with cervical disc disease?

Answer 10

22-50%

Question 11

loss.reduction of thoracic limb reflexes indicates lesion where in SC?

Answer 11

C6-T2 however in 34% of dogs the lesion was more cranial.

Question 12

how accurate are plain radiograph to identify location of disc dz in cervical spine

Answer 12

35%

Question 13

in a study of 33 dogs with Hansen type I disc disease the degree of SC compression evident on MRI was associated with pre surgical neurological status but was not associated with what?

Answer 13

post operative prognosis

Question 14

Foraminal intervertebral disc extrusions are ?

Answer 14

Cervical disc extrusions that are located close to, or within the intervertebral foramen itself.

Question 15

Foraminal intervertebral disc extrusions may be missed on myelography and sagittal MRI, what images should be acquired?

Answer 15

Transverse images in the areas of suspicion.

Question 16

What pathology forms a seagull shape with high signal intensity on a T2W sequence

Answer 16

hydrated nucleus pulpous extrusion

Question 17

in 92% of dogs hydrated nucleus pulpous has what intensity when compared to CSF in t2w images?

Answer 17

isointense

Question 18

how long should IVDD conservative management have exercise restriction.?

Answer 18

4-6 weeks

Question 19

when deciding if surgery is recommended, how should groups be divided ? (x3 groups)

Answer 19

1. neck pain only
2. rptd episodes neck pain
3. neck pain and near deficits.

Medical treatment for group 1. surgery for group 2 and 3.

Question 20

what are 3 techniques for sc decompression in the cervical spine?

Answer 20

1,ventral slot
2,dorsal laminectomy
3,hemilaminectomy

Question 21

what are the 1. advantages of ventral approach 2. disadvantages of ventral approach 3. advantages of dorsal approach 4. disadvantages of dorsal appraoch

Answer 21

1. minimal muscle dissection and ability for prophylactic fenestration
2. haemorrhage from internal vertebral plexus, poor field of view, inadequate exposure of lateral of foramina disc extrusion
3. more sc decompression, enamel easier access to laterally extruded disc material

Question 22

how big should a ventral slot be?

Answer 22

not more than 33% of the width and breadth of the vertebral body.

Question 23

why is Piezoelectric device suggested to bed safer for drilling nr spinal cord?

Answer 23

vibrates at low frog, 25-30hz so can only cut mineralised tissue. neurovascular tissues are only cut at freq >50hz

Question 24

how is slanted ventral slot different to a normal ventral slot and what are the suggested advantages?

Answer 24

access herniated disc material from caudal part of cranial vertebral body - do not remove large portion of annulus fibrosus.

Question 25

Should dogs of all weight have disc fenestration?

Answer 25

not in dogs >30kg

Question 26

What is the risk of fenestration of a partially ruptured or markedly degenerated disc?

Answer 26

dorsal extrusion of the intervertebral disc material

Question 27

how much disc material should be removed?

Answer 27

unknown but 1/3 to 1/2 has been suggested

Question 28

what rate do adverse events occur in ventral slot surgery ?

Answer 28

9.9 - 14.9%

Question 29

reported mortality rate in ventral slot surgery ?

Answer 29

3%

Question 30

What two main types of respiratory compromise occur post operatively in cervical surgery

Answer 30

1. ventilatory failure assoc w physical inability to move sufficient air into the lungs 2ndary to paresis or paralysis of the respiratory musculature. 2. may have reduced pulmonary gas exchange due to pneumonia or atelectasis due to prolonged anaesthesia

Question 31

What are reported complications from cervical surgery?

Answer 31

``` Respiratory Compromise Intraoperative Cardiac Dysrhytmias Blood Loss Neurologic deterioration Vertebral Instability and Subluxation Seroma ```

Question 32

disruption of which structures may lead to cardiac dysrhythmias ?

Answer 32

carotid arteries, vagus nerve, sympathetic trunk. Tectotegmental spinal tracts (UMN pre gnalgionic neutron of sympathetic system)).

Question 33

types of neurologic deterioration?

Answer 33

progression of pre surgery clinical signs, hornets, laryngeal paralysis

Question 34

How often was radiograph subluxation documented in dogs undergoing ventral slot?

Answer 34

8% of cases

Question 35

What factors affect prognosis after cervical disc herniation?

Answer 35

1. site of herniation - poss poorer prognosis w caudal herniations (caudal to C3/C4) 2. degree of CNS injury 3. duration of disease 4. thoracic limb sensory status 5. type of treatment

Question 36

Has duration of clinical signs been shown to affect outcome?

Answer 36

no, BUT dogs that can walk within 96h of surgery are likely to make full recovery, dogs that can't walk within two weeks are less likely.

Question 37

what percentage of clinical signs recur with conservative management for cervical disc dz?

Answer 37

36% or more

Question 38

In dogs that have had ventral slot surgery how many show a complete recovery at 1. 1 month and 2. 12 months

Answer 38

1. 90% | 2. 98%

Question 39

What is the recurrence rate for cervical disc herniatinon following ventral slot and what is the typical time frame

Answer 39

5-10% | 91 days

Question 40

Success rate for hemi’s in the cervical spine?

Answer 40

78-88%