Ch. 26-37: Neuro

Question 1

Noyes Vet Sx 2017 PQ

MRI vs CT to plan hemilaminectomies in chondrodystrophic dogs with IVDE

PQ What did authors conclude b/w MRI vs CT?

Answer 1

Similar surgical plans were developed based on MR vs CT in 43.5% - 66.6% dogs depending on observer

Intra-observer agreement in location, side, & size of planned hemilaminectomy based on CT vs MR ranged between 48.7-66.6%, 87-92%, & 51.2-71.7% of dogs respectively

Observers tended to plan larger laminectomy defects based on MR vs CT of the same dog

Conclusion: findings from this study indicated considerable differences in hemilaminectomies planned on preop MR vs CT imaging ; surgical location & size varied the most; side of planned hemilaminectomies was most consistent between imaging modalities

• MRI leads to bigger planned laminectomy compared to planned with CT. 48.7-66% agreement location, 87-92% side.*

Question 1

Hodgson Vet Sx 2017 PQ

Influence of in-house rehabilitation on the postoperative outcome of dogs with IVDH

PQ What was outcome of rehabilitation after hemilaminectomy?

Answer 1

More dogs returned to full neuro fxn (final MFS of grade 5) when in-house rehab was included in the postoperative mgmt. (33% compared to 9%)

Normal CP and ambulation returned earlier in control group (42 d & 14 d respectively) compared to group with rehab (49 d and 28 d)

The complication rate was higher in the control group (29%) compared with the group with rehab (16%)

Conclusion: in-house rehab should be included in postop mgmt. in dogs after sx tx of IVDH to improve neuro fxn and reduce postop complications

• 33% back to full fxn vs. 9%. But slower to walk and feel than control group. Lower comp rate. *

Question 2

McBride JVIM 2022

Developing a predictive model for spinal shock in dogs with spinal cord injury

MC diagnosis of dogs with SS for TL localization? LS?
Increased odds of final shock?
Paraplegic dog effect on spinal shock?
How to prioritize T3L3 with spinal shock based on exam findings?

Answer 2

data from 72 dogs
59 dogs with T3-L3 myelopathy and spinal shock ; 13 dogs with L4-S3 myelopathy

Median duration of clinical signs in the T3-L3 with spinal shock group was 24 hours

Clinical signs attributed to spinal shock were: decreased pelvic limb tone was observed in 14/59 dogs, decreased patellar reflexes were observed in 14/59 dogs, decreased withdrawal reflexes were observed in 45/59 dogs

Diagnoses based on MRI included acute intervertebral disc herniation (53), acute noncompressive nucleus pulposus extrusion (ANNPE; 5), and fibrocartilaginous embolic myelopathy (FCEM; 1)

Median duration of clinical signs in the L4-S3 myelopathy group was 48 hours

Diagnosis in all dogs with L4-S3 myelopathy was acute intervertebral disc herniation

When other independent variables were kept constant, the odds of spinal shock increased with decreasing weight and decreasing duration of clinical signs

** The odds of spinal shock in paraplegic dogs were 7.87 times greater than dogs with paraparesis

Dogs with decreased pelvic limb tone were 88% less likely to have a T3-L3 myelopathy with spinal shock

From the multivariable model, a formula was generated to calculate the odds of spinal shock using weight, duration of clinical signs, paraplegia (yes or no), and decreased pelvic limb tone (yes or no).

This study demonstrates that several key clinical factors can assist the clinician in prioritizing a T3-L3 myelopathy with spinal shock over an L4-S3 myelopathy:
** weight (lower), duration of clinical signs (<24 hours), more severe neurologic grade (eg, the presence of paraplegia as compared to paraparesis), and the presence of decreased pelvic limb tone

Question 3

Woelfel Vet Sx 2021

Outcomes and prognostic indicators in 59 paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion

Factors with outcome?
Conclusion?

Answer 3

extensive epidural hemorrhage (DEEH) and thoracolumbar IVDE

Lab and LabX most common

Recovery of ambulation in 77.3% of dogs w/ and 37.8% of dogs w/o pain perception prior to sx

Progressive myelomalacia in 5% of dogs (1 w/ pain, 2 w/o pain sensation)

24% postop complication rate

independent factors associated with outcome: clinical severity, number of vertebrae w/ signal interruption in half Fourier single-shot turbo spin echo sequences (HASTEi) and ratio of vertebral sites decompressed to HASTEi

conclusion: paraplegic medium-lg breed dogs w/ extensive epidural hemorrhage had less favorable outcome after sx decompression than paraplegic dogs w/ TL-IVDE

Question 4

Fenn JVIM 2020 PQ?

Association between anesthesia duration and outcome in dogs with surgically treated acute severe spinal cord injury caused by thoracolumbar intervertebral disk herniation

Main significant finding?

Answer 4

60% of cases were ambulatory at 1yr,
40% failed to recover including 25% euth for progressive myelomalacia

mean anesthetic time was sig shorter in dogs that regained ambulation vs those that did not

significant neg association b/w both duration of sx and total anesthetic time and ambulation at 1yr when controlling for body weight and number of spaces operated on

causal relationship unknown: could be related to CV and perfusion variable under GA or complications at sx (ex hemorrhage)

Question 5

Hall VCOT 2021

Approach to and practice of disc fenestration in the management of intervertebral disc extrusions in dogs: a questionnaire survey

Answer 5

71% routinely used disc fenestration
Lower amongst surgeons (55%) compared to neuro (82%)
44% only affected disc, 37% 2-3 discs, 19% 4-6 discs
Only 25% fenestrated in the cervical spine

Method
scalpel blade/curette 71%
air drill and burr 14%
needle 11%
others 4%

45% has experience complications with hemorrhage being the most common
Others include further nucleus pulposus material in canal
spinal nerve root damage
pneumothorax
discospondylitis
spinal cord damage
damage to aorta

Question 6

Hamilton-Bennett Vet Sx 2019 PQ

Clinical presentation, MRI features, and outcome in 6 cats with lumbar degenerative IVDE treated with hemilaminectomy

Answer 6

Our population included 6 cats with median age 8.6 yr – mostly male (5) and purebred cats (4)

Acute onset & short duration of progressive

CS of myelopathy was most common presentation; spinal hyperesthesia in 3

A large volume of extradural material on MRI w/I lumbar vertebral column of each cat, causing marked SC compression

Most common sites affected by L2-L3 (2) and L6-7 (2)

FU after hemilaminectomy was available in 5 cats: 4 had normal voluntary motor function, 1 had recurrence of acute paraplegia, compromised nociception, and extensive T2W hyperintense intramedullary lesion on MRI

All 4 cats with preop urinary incontinence remained incontinent for at least 1 wk despite good voluntary motor fxn of pelvic limbs

Conclusion: IVDE was diagnosed by MRI in all 6 cats – most often at L2-3 / L6-; hemi resulted in good to excellent outcome in 4/5 cats

Question 7

Takahashi Vet Sx 2020 PQ

Effect of durotomy in dogs with thoracolumbar disc herniation and without deep pain perception in hind limbs

What recommended? PQ

Answer 7

116 dogs
The percentage of dogs regaining ambulation was greater when durotomy was performed (56.9%) than when dogs were treated with hemilaminectomy alone (38.5%; P = .04).

In the hemilaminectomy group, 14 dogs died of suspected PMM, while no PMM was detected in the durotomy group.

Durotomy, breed, surgical site, and LHT2 (length of hyperintensity compared to L2 vertebral body length) influenced recovery.

French bulldogs less likely to make a good recovery
Daschunds “tended to” recover better than other breeds (p = 0.313)

• Performing a durotomy in combination with decompression improved the return to function and prevented PMM in our clinical setting. - -Surgeons should consider durotomy in dogs with TL-IVDH and loss of DPP in hind limbs to improve surgical outcome. *

Question 8

Schmidli VCOT 2019 PQ

Fractures of the 2nd cervical vertebra in 66 dogs and 3 cats: a retrospective study

PQ Px, Sx vs MM, Mortality rate

Answer 8

Crossbreeds and Labrador Retrievers most presented dog breeds ; Median age 2 yr
Motor vehicle accident most common inciting cause, followed by frontal collision

Most common neurological deficits ranged cervical pain with or without mild ataxia (22/68) to tetraparesis (28/68) and tetraplegia (11/68)

Treatment – 37/69 had sx fracture stabilization, 27/69 had MM and 5/69 immediately euthanized

Of all treated cases, * 52/58 showed ambulatory recovery (23/25 of conservatively treated & 29/33 sx treated) whereby in 40/52 cases full recovery without persisting signs was achieved *

Conclusions: fx of axis commonly occur in young dogs, in many cases neuro deficits relatively mild; generally animals with a fractured axis have a very good prognosis for functional recovery; risk of periop mortality lower than previously reported

Question 9

Gallastegui VRUS 2019 PQ

MRI has limited agreement with CT in evaluation of vertebral fx of canine trauma patient

Answer 9

128 vertebrae were evaluated for the presence of fractures.
Imaging studies were read by two observers blinded to the history.

While both observers had similarly high sensitivity and specificity for simple detection of any fractured vertebrae, interobserver agreement was only moderate (𝜅 = 0.584).

When evaluations were specifically limited to detection of structurally unstable fractured vertebrae both observers showed improved specificity and interobserver agreement became substantial (𝜅 = 0.650).

Complete agreement for exact fracture location between MRI and CT results was only achieved in 14.3-32.6% of fractured vertebra with up to 79% of fractures being missed in some vertebral structures.

This suggests that although MRI may be able to detect the presence of fractured vertebrae, it is not able to replace CT for the complete evaluation of the traumatized spine and documentation of fracture morphology.

Question 10

Skytte JAVMA 2018

Relationship of preoperative neurologic score with intervals to regaining micturition and ambulation following surgical treatment of TL disc herniation in dogs

Answer 10

Mean interval from surgery to regaining micturition was 4.1 days and mean interval from sx to regaining ambulation was 13.8 days
These intervals differed significantly
Significant negative correlations with MFS were ID for interval to regaining micturition and interval to regaining ambulation
Dogs with preop MFS of 4 took mean of 1.9 d to regain micturition, whereas dogs with MFS < 1 took mean 15.5 days
No other correlations with outcome were identified
Conclusion: the amount of time required for dogs to regain micturition and ambulation following surgery for TL IVDE was correlated with preop severity of CS, as reflected by preop MFSs

Question 11

Harris VCOT 2019/2020

Introduction of disc material into the vertebral canal by fenestration of TL discs following decompressive surgery

Answer 11

7 dogs showed presence of new disc material in vertebral canal post fenestration
This preliminary study shows additional disc material can be forced into vertebral canal by fenestration following decompressive surgery, with frequency of 7/21
Conclusion: remember to check canal after fenestration

Question 12

Guevar Vet Sx 2020

Minimally invasive spine surgery in dogs: evaluation of the safety and feasibility of a TL approach to the spinal cord

Answer 12

Technique
Used a fluoro tiltable table, a surgical microscope, Leica M525 F40; a tubular retractor system and Gelpis were used (“odd-legged”)
Used a 3 mm fluted matchstick drill bit & controlled with foot pedal for bone removal
Bayonetted instruments used for mobilization of soft tissue structures
The vertebral canal was successfully accessed, & the ventral aspect of the SC was ID at all sites
No neuro deterioration was observed
Postop pain was not different compared with baseline except in 1 dog on day post-op
Conclusion: minimally invasive spinal sx was safe and feasible technique

Question 13

Upchurch VCOT 2020

Effect of duration and onset of CS on short-term outcome of dogs with Hansen type I TL IVDE

Answer 13

Duration of CS prior to surgery and rate of onset of signs did not correlate with return of pain sensation, urinary continence or ambulation
Preoperative neuro grade was the main variable that was found to be associated with outcome
Dogs with grade 2 and those operated on by board-surgeon took less time to regain continence than grade 0
Dogs with grade 2 or 3 on presentation also had significantly shorter time on regaining ambulation vs grade 0
Conclusions: delay from initial CS of IVDE to surgery is unlikely to affect the ultimate outcome or the length of time for a dog to regain pain sensation, urinary continence or ambulation; the rate of onset of signs likewise does not influence these outcomes

Question 14

Jeffery Vet Sx 2020

Extended durotomy to treat severe spinal cord injury after acute thoracolumbar disc herniation in dogs
26 dogs

Answer 14

18 dogs had regions of pink-purple discoloration of spinal cord
Improved after durotomy
1 case had softened/liquefied parenchyma
Did not regain ambulation
16 dogs recovered to walk between 12 days and 6 months
All but one regained complete urinary and fecal continence
1 dog developed progressive myelomalacia
Dogs that recovered pelvic limb function had a shorter gap in myelographic columns
Estimated probability of 64% that the outcome after durotomy was better than 68%
95% probability that the outcome was better than 55%

Question 15

Schmierer Vet Sx 2020

Randomized controlled trial of pregabalin for analgesia after surgical treatment of intervertebral disc disease in dogs

Answer 15

23 dogs in group O, 23 dogs in group OP
CMPS-SF lower in group OP during the whole observation by a mean of 2.5
Group OP had a more rapid increase in nociceptive threshold during the says after surgery
Increased mechanical threshold by 6.89 N per day for the near measurement and 7.52 N for the far measurement
Serum analysis
Substantial variability occurred
Only 1 dog in the OP group had concentrations below 0.38 ug/mL in all 3 measurements
Mean concentrations of 5.1, 4.71, and 3.68 at days 1, 3, and 5
Four dogs in group O and 1 dog in group OP needed rescue analgesia

Question 16

Nakamoto Vet Sx 2020 PQ

Outcomes of dogs with progressive myelomalacia treated with hemilaminectomy or with extensive hemilaminectomy and durotomy

PQ recommended procedure?

Answer 16

extensive hemilaminectomy and durotomy (EHLD) to control progressive myelomalacia (PMM)

28 dogs - 18 HL, 10 EHLD

The survival rate was higher in the EHLD group (P = .03) compared with the HL-alone group.
11/18 dogs treated with HL survived, while seven of 18 dogs died (median, 5 days after surgery).

In the EHLD group, 10 of 10 dogs survived postoperatively.

Baseline characteristics were not associated with postoperative survival outcomes.
According to multivariate analysis, EHLD was the independent factor associated with an increase in survival rate (P = .0002).
T2 length ratio in univariate but not multivariate

• Conclusion: EHLD durotomy at the intramedullary hyperintense region on T2W-MRI improved the survival rate of dogs with PMM compared with dogs treated with standard HL. – supports treatment with EHLD in dogs with PMM *

Question 17

Cordie VRU 2023

MRI features can help to confirm a diagnosis of progressive myelomalacia (PMM), but may not be accurate in dogs lacking characteristic clinical signs at the time of imaging

Answer 17

Progressive myelomalacia (PMM) is a fatal sequela of acute thoracolumbar IVDE in dogs, w/ unpredictable onset in the days after the inciting injury. No single reliable diagnostic test is currently available.

MRI features such as T2-weighted spinal cord hyperintensity & loss of subarachnoid signal in a half-Fourier single-shot turbo spin echo (HASTE) sequence have been associated w/ PMM, but are sometimes present in dogs w/ severe deficits.

Retrospective case-control study → Comparison of MRI findings in 22 dogs w/ a clinical or histopath dx of PMM & 38 Deep pain negative paraplegic dogs

Length of T2-weighted hyperintense spinal cord change and HASTE signal loss were significantly associated w/ clinically evident PMM (P = .0019 and P = .0085)
However, there were NO significant differences btwn groups when analysis was restricted to dogs not yet showing clinical signs of PMM.

The PMM group also had significantly shorter compressive lesions than the control group (P = 0.026), suggesting a possible role of more severe focal pressure at the extrusion site.

A segment of total loss of contrast enhancement in the venous sinuses & meninges → (not previously described), was more common in the PMM group & the difference approached significance (P = 0.054).

Conclusions: Findings show that MRI features can support the dx in dogs w/ clinical evidence of PMM, & absence of these features supports absence of PMM at time of imaging. However, their absence does not reliably differentiate dogs w/ imminent progressive myelomalacia from other dogs w/ severe deficits following IVDE.

Question 18

Martin JSAP 2020

Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion

Answer 18

7/151 dogs in the early surgery group lost pain perception overnight compared to 15 of 122 in the delayed surgery group (Fisher’s exact test, P = 0.025). Number-needed-to-treat analysis suggested that 14 dogs (95% confidence interval: 7-106 dogs) need early surgery to prevent one losing pain perception overnight. Five of the seven dogs that lost pain perception in the early surgery group recovered pain perception by 3 weeks post-operatively, compared to eight of 14 in the delayed group.

Clinical significance: This study suggests that an overnight delay before spinal decompression increases the risk of clinically meaningful deterioration in dogs unable to walk following thoracolumbar disc extrusion.

Question 19

Zidan JVIM 2020

Long-term postoperative pain evaluation in dogs with thoracolumbar intervertebral disk herniation after hemilaminectomy

Answer 19

At the incision site of SCI dogs, MST was significantly lower than in healthy dogs for 42 days postoperatively, but not subsequently. However, 4/27 dogs had control site MST below the reference range 1 year after surgery.

Conclusions and clinical importance: Mechanical sensory thresholds normalize by 6 months after surgery in most dogs with SCI. Approximately 15% of SCI dogs may develop chronic neuropathic pain. Improving long-term pain assessment of SCI dogs is important for offering treatment options and advising owners.

Question 20

Longo JVIM 2021

Association of magnetic resonance assessed disc degeneration and late clinical recurrence in dogs treated surgically for thoracolumbar intervertebral disc extrusions

Answer 20

92 dogs were included, of which 33 (35.9%) later presented signs compatible with recurrence of TL IVDE.
Recurrence was assessed directly by a neurology specialist in 22/33 (66.7%) cases or by the referring veterinary surgeon in the remaining cases.
Multiple IVDs were extruded and operated in 5 cases, with 2 affected sites in each.
The association indicated a point estimate of increased hazard of recurrence of ~290% vs dogs that do not have another completely degenerate disc.
Recurrence was confirmed by a second MRI in 8/33 cases.
1 case herniated at the original site, 3 cases had new herniation in 1 of the adjacent IVDs, 2 cases herniated within 1 IVD space away, and the remaining 2 cases herniated more than 1 IVD space away from the initial site.
The new herniating site was outside the T10-L3 region in 2 cases, both at L5-L6 which were reassessed. Initial IVD status in these cases was “completely degenerate” (5) and “partially degenerate” (3).

Question 21

Peschard VRU 2023

Follow-up MRI appearance of the surgical site in dogs treated for thoracolumbar intervertebral disc herniation & showing ongoing or recurrent neurological symptoms

Answer 21

Re-herniation & reoperation rates of 4.5%–36% are reported in canine patients treated for IVDH.
Single-center, retrospective, descriptive study
21 dogs and 42 MRI studies - Chondrodystrophic breeds, specifically Dachshunds, were overrepresented.
Mean number of days bwn surgery & second MRI was 335 (range 2–1367).
Metallic susceptibility artifacts were seen in 7 of 21 cases (33%), but these were limited in extent, spanning an average 1.3 vertebral bodies.
11 cases spinal cord compression suspected to be clinically significant was found at the surgical site
10 cases → extradural compressive material consisted of intervertebral disc material only, or a combo of intervertebral disc material & hematoma or inflammatory changes
1 case → Displaced articular process & fibrous tissue
Newly described complication of mini-hemilaminectomies.

The results of this study supported the use of MRI as a diagnostic modality for spinal imaging following IVDH surgery, and showed that the presence of extradural disc material at a spinal surgical site is common along w/ various vertebral & paravertebral changes.

Question 22

Kristiansen VCOT 2022

Hydrated nucleus pulposus extrusion (HNPE) in dogs: thoracolumbar compared to cervical cases

Answer 22

15 cervical and 21 TL cases of HNPE
Fewer dogs were condrodystrophic in the cervical group compared to TL group (13 of 36 total)
>90% had acute onset
Strong activity more commonly reported in history for TL
TL HNPE more often painful and extruded disc material more often lateralized
72% were nonambulatory on presentation
Mean modified Frankel score was 3
More TL HNPE treated surgically than cervical (11/21 vs 4/15)
Treatment choice corresponded to spinal cord compression
No difference in outcome between cervical and TL HNPE or conservative or surgical treatment
All patients were ambulatory at followup

Conclusion:
HNPE is not limited to C-spine
Dogs with TL HNPE are often more painful than C-spine cases and are often more lateralized with more disc extrusion
Outcomes remain similar

Question 23

Bridges JVIM 2022

Prevalence and clinical features of thoracolumbar intervertebral disc-associated epidural hemorrhage in dogs

Answer 23

Epidural hemorrhage is suspected to occur secondary to laceration of the intervertebral venous plexus ventral to the spinal cord during disc extrusion.
Epidural hemorrhage contributes to spinal cord compression and causes secondary spinal cord injury due to direct cytotoxicity after exposure to hemorrhage and hemorrhagic byproducts.
Because of high concentrations of polyunsaturated fatty acid chains and reduced protective mechanisms against oxidative damage, the central nervous system is exceedingly susceptible to cytologic damage from free radicals produced by the breakdown of erythrocytes
Study: 160 dogs with TL-IVDH that had MRI and hemilaminectomy
39% had EH
Younger than dogs without
French bulldogs overrepresented 4.1x
More likely to present with clinical signs <48 hours than dogs without 2.4x
More likely to be non ambulatory 2.1x
More likely to have <50% spinal cord compression 2.3x
More likely to have longer longitudinal spinal cord compression (3 vs 1 space)

More likely to have greater intrinsic spinal cord change
Location of IVDH in French bulldogs with EH more likely to be thoracolumbar 10.8x

Question 24

Fowler JFMS 2022

Outcome of thoracolumbar surgical feline intervertebral disc disease

Answer 24

Difficulty walking 54.2%
L4-S3 localization 34%
Surgery outcome
Positive in 62.5% and 91.3% at 2-week recheck
that both grade I cats had improved (100%).
Of the grade II cats, 14 had shown improvement (70% one had an unchanged examination (5%).
Of the grade III cats, three had improved (50%) and one was lost to follow-up (50%).
Of the grade IV cats, one had improved (50%) and the other was lost to follow-up (50%).
Grade and outcome not sig
No association was identified between the age of the patient and the grade of IVDD.
No association was identified between the presenting grade of IVDD and the clinical outcome at the time of discharge or at the time of recheck evaluation.

Question 25

Bibbiani JFMS 2022

Prevalence, clinical presentation and MRI of intervertebral disc herniations in cats
Retrospective, 43 cats

Answer 25

intervertebral disc herniation (IVDH), intervertebral disc extrusion [IVDE], intervertebral disc protrusion [IVDP], acute non-compressive nucleus pulposus extrusion (ANNPE)
A total of 50 IVDHs were identified: 39 cats were diagnosed with a single IVDH and four with multiple IVDHs.
The most common type of IVDH was ANNPE (n=22), followed by IVDP (n=19) and IVDE (n=9).
Neuroanatomical localisation: L4–S3 (n=19/43, 44%), T3–L3 (n=18/43, 42%) and C1–C5 (n=6/43, 14%).
Cats with a single IVDH were statistically significantly associated with a diagnosis of ANNPE (P=0.023) compared with cats with multiple IVDHs affected by IVDP (P=0.004).
Males were more commonly affected by IVDE (P=0.020) and females by ANNPE (P=0.020).
Cats with IVDP had a longer duration of clinical signs (P <0.001) than cats with ANNPE and demonstrated milder neurological deficits (P=0.005).
IVDEs were statistically significantly associated with spinal hyperaesthesia (P=0.013), while ANNPEs were not (P=0.014).
Conclusions: ANNPE, IVDP and IVDE are each associated with distinctive clinical scenarios.
Thoracolumbar and mid-to-caudal lumbar regions are the most affected, followed by the cranial cervical spine

Question 26

Sakaguchi JAVMA 2023

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation

Answer 26

retrospective cohort study, medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed
Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs.
grade 1, spinal hyperesthesis only
grade 2, ambulatory paraparesis and ataxia
grade 3, nonambulatory paraparesis
grade 4, paraplegia with intact deep pain sensation
grade 5, paraplegia with no deep pain sensation
The total volume of the affected intervertebral disks was significantly larger than the internal control.
Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity.
There was no correlation between the maximal transverse spinal cord compression ratio and the neurologic severity
findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity

Question 27

Zanoguera JSAP 2023

Does surgical timing affect the rapidity of recovery in deep pain-entire nonambulatory dogs with thoracolumbar intervertebral disk extrusion?

Answer 27

Data on non-ambulatory dogs with preserved deep pain perception in both hindlimbs and surgically treated for thoracolumbar intervertebral disc extrusion were prospectively collected from three referral hospitals
One hundred and fifty-one dogs were included.
Median time from admission to surgery, including imaging, was 180 (interquartile range, 65.4 to 240) minutes.
All dogs were operated within 72 hours.
Follow-up was available for all 151 dogs and ranged from 1 to 21 months.
All but three dogs, which were all grade IV at presentation, recovered the ability to ambulate.
In both univariable and multivariable models, only duration of surgery and neurological (Frankel) grade at presentation were significantly associated with the rapidity of recovery of ambulation.
Conclusions:
Delay between onset of clinical signs and presentation and time between presentation and spinal surgery was not associated with the rapidity of recovery of ambulation in dogs surgically treated for thoracolumbar intervertebral disc extrusion
Duration of surgery and neurological grade at presentation were significantly associated with rapidity of recovery of ambulation

Question 28

Paran JSAP 2023

Prevalence of gastroesophageal reflux in dogs undergoing MRI for a thoracolumbar vertebral column pathology

Answer 28

Retrospective descriptive study
The thoracic part of the esophagus was retrospectively assessed for presence and quantification of fluid on two T2 weighted sequences
Anesthetic records were reviewed for the presence of regurgitation and detailed anesthetic protocols.
Fifty percent (95% confidence interval: 45 to 57%) of included dogs had evidence of gastroesophageal reflux.
Reflux was not associated with the individual breed, age, sex, neuter status or body weight.
Brachycephalic dogs did not demonstrate significantly higher rates of reflux compared to non-brachycephalic dogs.
A larger volume of reflux was associated with a higher chance of regurgitation.

Question 29

Wachowiak JVIM 2023

Thoracolumbar myelopathies in Pug dogs
Pug spinal issues: Constrictive myelopathy (CM) and Spinal arachnoid diverticulum (SAD)

Answer 29

Both diseases are associated with SC compression and meningeal fibrosis (arachnoid, dural or borth) –> form a constrictive, circumferential band of connective tissue forming in CM and a CSF-filled subarachnoid cavity forming in SAD
Caudal articular process dysplasia (CAPD) and hemivertebrae are also common in pugs
Instability associated with CAPD may lead to CM from gradual micromotion leading to meningeal fibrosis –> these adhesions can disrupt normal CSF flow possibly leading to SAD

Study:
32 pugs diagnosed with chronic progressive T3-L3 myelopathy; all dogs had CT and MRI
MRI categories: CM only, CM plus other non-CM conditions, or non-CM conditions
CT was used to report on CAPD
19 dogs had necropsy (died or were euthanized)

Results:
MRI revealed:
3/32 (9%) with CM only
17/32 (53%) with CM plus > 1 other myelopathy
So ~63% had CM
11/32 (34%) with non-CM myelopathy
1/32 (3%) with no abnormalities
19/32 had >1 myelopathy (59%)
15/32 had >1 site of SC compression (47%)
All dogs had CAPD at >1 site on CT in T3-L3

Conclusion: CM affected ~60% of pugs with chronic TL myelopathy, with ~60% having multiple concurrent myelopathies and ~50% with multilevel disease
No relationship b/w CAPD anatomic location and most severe myelopathy or myelopathy type

Question 30

Bonelli JAVMA 2019

Neurologic and MRI features of GSD with cervical spondylomyelopathy 10 cases (2006-2018)
9 male and 1 female ( mean age 6.2 yr) GSDs w/ CSM assessed

Answer 30

Dogs classified as chronic (9) or acute (1) CSM
9 dogs had ataxia: 1 dog only signs of cervical hyperesthesia
Neurologic examination findings localized lesion to cervical portion of vertebral column in each dog
Main SC compression site C6-7 (5), C5-6 (4), C4-5 (1) IV spaces; osseous proliferation of articular processes was the sole or contributory cause of these compressions for 6/10 dogs
8 dogs had dorsal compression of SC as result of ligamenta flava hypertrophy
Conclusions: the 10 GSD of present retrospective case series had CSM that was often characterized by osseous changes and ligamentous component & older than dogs of other breeds (Great Dane & Mastiff) w/ osseous-assoicated CSM described in previous reports

Question 31

Rohner VCOT 2019

Short-term clinical and radiographical outcome after application of anchored intervertebral disc spacers in dogs with disc-associated cervical spondylomyelopathy

Answer 31

37 cases enrolled in study, and outcome assessed at 6 wks and 3 mo

Outcome at 3 mo available in 25 dogs; improvement in neuro status in 25/25 cases
Most common postop complication – screw loosening &/or breakage (22) then subsidence (15)
Major complications in 5 dogs – 3 had revision sx with plate ventral due to implant failure; 1 had incomplete decompression, 1 dog abscess & pressure sore beneath neck brace 🡪 MM with bandage and abx ;
3 catastrophic short-term complications – 1 died due to gastric perforation…. 1 disc extrusion in C-spine and euthanized and 3rd dog progressive cervical pain 🡪 extradural cartilage material at site of sx and hemi done but no imrpovement and euthanized
4 dogs needed revision surgery
Conclusion: distraction/stabilization of DA-CSM in dogs with C-LOX device resulted in short-term clinical improvement in 33/37 cases ; the high incidence of screw loosening was taken into consideration and modification with new locking system and new screw dimensions was required

Question 32

Waschk VCOT 2019

Cranioovertebral jxn anomalies in small breed dogs with atlantoaxial instability: a multicenter case-control study

Answer 32

122 dogs enrolled (61 w/ and 61 w/o AAI)
Only dogs with AAI had dens axis anomalies like separation (20) or short-rounded conformation (35)
Patients with AAI more likely to have atlantooccipital overlapping based on transection of McRae’s line by the dorsal arch of the atlas (OR 5.62), a transection of Wackenheim’s clivus line (OR 41.62) and rostral indentation of the occipital bone (OR 2.79)
Patients with AAI were less likely to have a larger clivus canal anagle (OR 0.94) and larger occpital bone lengths (OR 0.89)
Conclusions: small breed dogs with AAI are more likely to have other CVJ anomalies, such as AO overlapping or dens anomalies; the grade of brachycephaly does not differ between patients with and without AAI;

Question 33

Schmitt Vet Sx 2021

Computed tomography evaluation of proposed implant corridors in canine thoracic vertebrae

Answer 33

39 dogs were included
Table 1 provides summary of the width/length T1-T9
Average width ranged from 3.8-5.2 mm (T1 widest)
Average length ranged from 13.3-17.5 mm (T1 shortest and T6 longest)
Corridor angles decreased from cranial to caudal
Significantly between between T1 and T3, no difference between T4 - caudally to T9
Figure 4 shows average angle of safe corridors relative to the vertical axis of each thoracic vertebrae
T1 mean 36.39
T2 mean 31
T3 mean 26.4
T4 mean 24.82
T5-T9 mean 22.91-23.15
Three observers did not agree with each other
Observer 1 and observer 5 were most similar
Based on measurements obtained in this study, commercially available sizes of cortical screws and positive profile pins would be suitable for placement in normal T1-T9
T5-T9 approximately 23 degrees from the mid-sagittal plane
More variability in the cranial thoracic spine (T1-T3)

Question 34

Planchamp Vet Sx 2022

Determination of cutoff values on computed tomography and magnetic resonance images for the diagnosis of atlantoaxial instability in small-breed dogs

Answer 34

control group, “potentially unstable”, and an AAI-affected group
Cutoff values
ventral compression index (VCI) (sens 100% and 100% and spec 94.54% and 96.67%)
>0.16 in extended
>0.2 in flexed
Other measurements C1-C2 overlap, C1-C2 angle, atlantoaxial distance, basion-dens interval, dens-to-axis length ratio) had lower sens and spec (75-96% and 70%-97%)
Combination of measurements did not increase sens and spec compared with VCI as a single measurement

Question 35

Argent JSAP 2022

Recurrence of signs consistent with cervical intervertebral disc extrusion in dogs

Answer 35

Initial cervical disc extrusion
Complete recovery medical 30.3%
Complete recovery surgical 69.7%
underwent ventral slot decompression without prophylactic fenestration of other disc spaces.
Recurrence of consistent clinical signs in 34%
33% surgical
Commonly involved adjacent disc
9/16
1/16 at same site
36% medical
Mostly at the same site
4/8 at same site
none at adjacent site
80% recurred within 2 years of diagnosis
55% within 1 year

Question 36

Nye JVIM 2020

Long-term clinical and magnetic resonance imaging follow-up of dogs with osseous-associated cervical sponylomyelopathy

Answer 36

Most affected site on initial MRI had progressed in 4 (all tx medically), improved in 4 and unchanged in 3
Clinically all dogs except 2 (18%; both tx medically) were improved or static
Initially 83% of IVS had stenosis vs 82% at follow-up; 45% were unchanged, 20% improved, 40% worsened
Morphometry ID significant canal decrease in vertebral canal at C4-C5 to C6-C7 and sig progression of articular process irregularities at C3-C4 and C6-C7
Conclusion: long term follow-up did not ID clinical or MRI progression in the majority of dogs

Question 37

Bonelli VRU 2021

Association of neurologic signs with high-field MRI findings in 100 dogs with osseous-associated cervical spondylomyelopathy

Answer 37

73/100 (73%) were giant breeds, 27/100 (27%) large breeds.
Mean and median ages were, respectively, 3.1 and 2 years (0.3–9.75 years), with 2.6 and 2 years for giant-breed; and 4.4 and 4 years for large-breed dogs.
The majority of dogs were male (75%) with chronic presentation (89%), more than one site of spinal cord compression (78%) and foraminal stenosis (91%).
Dogs with multiples sites of spinal cord compression were more likely to have severe spinal cord compression (p < 0.001), severe foraminal stenosis (p < 0.001) and ligamentum flavum/soft tissue proliferation (p = 0.03) than those with a single compressive site.
There was a weak correlation between neurologic grade and severity of spinal cord compression (r = 0.27; p = 0.007), number of affected sites (r = 0.24; p = 0.0183) and spinal cord T2W hyperintensity (r = 0.24; p = 0.0152).
Intervertebral disc degeneration was seen in 80% of dogs.
Age did not appear to have a prominent role in the manifestation of OA-CSM.

Question 38

Olender JAVMA 2023

Cervical jerks as a sign of cervical pain or myelopathy in dogs

Answer 38

Retrospective study
20 dogs with a history of unilateral or bilateral cervical jerks associated with cervical pain or myelopathy.
13 of which were French Bulldogs.
Jerks all presented as focal repetitive rhythmic contractions on the lateral aspect of the neck (on one or both sides).
All dogs had a diagnosis of cervical intervertebral disk extrusion (IVDE), half of them at the C2-C3 level.
No dogs presented with extrusion caudal to the C4-C5 intervertebral disk space.
The prevalence of myoclonia among all dogs diagnosed with IVDE was 3.77% (20/530) in our hospital.
Conclusion: Cervical jerk associated with cervical pain or myelopathy may represent myoclonus and was exclusively secondary to cranial cervical IVDE in this study. Full recovery was observed following medical or surgical treatment of IVDE. The exact origin and classification of this involuntary movement has yet to be established.

Question 39

Murthy JVIM 2023

Horner syndrome as a physiological biomarker of disease in canine cervical myelopathy

Answer 39

Horner’s Syndrome = disruption/injury of the oculosympathetic neural pathway –> miosis, (+/- ptosis), enophthalmos and protrusion of the nictitating membrane +/- anhidrosis (pneumonic ‘My 3rd Sunken Toe)
Cervical myelopathy can cause Horner’s syndrome through damage of 1st-order neurons –> more commonly seen with noncompressive intraparenchymal lesions rather than compressive extraparenchymal lesions
Study
99 control cases (cervical myelopathy w/o Horner syndrome, CM w/o HS) vs. 93 dogs with CM w/HS
Non-compressive disease more common in HS group (58%) than w/o HS group (9%)
Most common diseases in HS group was FCE (47%)
Most common disease in control group was IVDE (77%)
MRI findings:
Horner group: parenchymal hyperintensity (95%)
Control group: parenchymal hyperintensity (51%)
Outcome:
13 dogs w/ HS died –> had more extensive MRI lesions relative to adjacent vertebral length (200%)
80 dogs w/ HS survived –> less extensive MRI lesions relative to adjacent vertebral length (110%)
Lateralization of HS and MRI findings only matched in 54% of cases
Overall survival:
HS 86%
Control 96%
Conclusion: HS with CM is more commonly associated with noncompressive intraparenchymal disease

Question 40

Bonelli JVIM 2023

Magnetic resonance imaging and neurologic characterization of combined osseous- and disc-associated cervical spondylomyelopathy in dogs

Answer 40

see pics

Wobbler Syndrome (CSM, cervical spondylomyelopathy) is a disorder that affects the cervical vertebral column and is characterized by compression of the cervical spinal cord, nerve roots, or both
2 forms of CSM exist which can be present separately or together
Disc-associated CSM (DA-CSM) occurs when spinal cord compression is secondary to IVD protrusion
Osseous-associated CSM (OA-CSM) occurs when there is compression of the spinal cord resulting mainly from osseous proliferation of the articular processes
Hypertrophy of the ligamentum flavum can also be observed
Study:
60 dogs with DA-CSM and OA-CSM out of 232 total CSM cases (~25%)
Results:
35/60 (58%) were large breeds; 22/60 (37%) were giant breeds
Median age was 6.6 and 7 years, respectively
40/60 (67%) had concurrent osseous and disc associated spinal cord compression at the same location
This was the main compression site in 32/40 (80%) of those cases
Dogs with both osseous and disc-associated compressions at the same site were more likely to have a higher neurologic grade
Conclusions
67% had combined OA-CSM and DA-CSM at same location; these dogs were also more likely to have a higher neurologic grade

Question 41

Marinho VCOT 2022

Comparison of Cervical Stabilization with Transpedicular Pins and Polymethylmethacrylate versus Transvertebral Body Polyaxial Screws with or without an Interbody Distractor in Dogs

Answer 41

Various vertebral distraction-stabilization methods are reported for CSM: combination of bicortical transpedicular pins + PMMA placed into vertebral bodies has been associated with a high rate of vertebral canal and intervertebral foramen penetration
Transvertebral body screws + PMMA or Locking Plates have been reported as being effective in stabilizing the vertebral column of cSM dogs
An addition of an interbody spacer significantly increases stiffness in these constructs
Monoaxial or polyaxial pedicle screws have been studied to stabilize LS spine after decompressive surgery and were found to be more stable than pins/PMMA
Study:
Compare bicortical screws/PMMA and transvertebral body polyaxial screws w/ or w/o an interbody distractor in the caudal C-spine
10 C-spine (C2-T3) models were used
Four groups applied to C6-7 sequentially:
Intact group
Transvertebral body polyaxial screw w/ interbody distractor (polyaxial + distractor)
Transvertebral body polyaxial screw w/o interbody distractor (polyaxial - distractor)
Bicortical transpedicular pins/PMMA (pin-PMMA)
Angular ROM (AROM) in flexion and extension was measured at C4-5, C5-6, C6-7 in all groups
Results:
Intact group had significantly higher AROM than treated groups in flexion and extension
Flexion at C6-7: Distractor 72% less, no distractor 60% less, pin-PMMA 69% less than intact group AROM
Extension at C6-7: Distractor 93% less, no distractor 90% less, pin-PMMA 91% less
No difference between each treated group
Stiffness during flexion-extension was significantly greater in the treated than intact group: distractor was 81% greater, no distractor 73% greater, pin-PMMA 78% greater
Conclusions:
Polyaxial screw stabilization was comparable to pin-PMMA
Adding a distractor increased stiffness but did change AROM of the polyaxial constructs (not significant)

Question 42

Muller VCOT 2022

Evaluation of Paraspinal Musculature in Small Breed Dogs with and without Atlantoaxial Instability (AAI) Using Computed Tomography

Answer 42

Conclusions:
Hypaxial muscle changes were only observed at Occiput-C1 level –> indicated a limited role of muscular adaptation in AAI patients

Question 43

Morton JAVMA 2022

Indications, complications, and mortality rate following craniotomy or craniectomy in dogs and cats: 165 cases (1995-2016)

Answer 43

Most common neurolocalization forebrain (66.7%)
Rostrotentorial 70.3% and caudotentorial 19.4% most common approaches
Indications
Meningioma 52.8%
Complications within 24 hours 35.2% and 52.1% within 1-10 days postop
Periop
Hypotension 23%
Anemia 16.4%
Postop
Neurologic deficits
Seizures
Postop anemia
Pneumonia
Long-term 39.4%
Seizures and neurologic deficits most common
Mortality rate 14.5% within 10 days postop
Risk factors for complications during surgery and within 24 hours
Preop seizures 80% lower odds of complications
Surgical approach rostrotentorial approach or other had greater odds
Postop fentanyl 3.6 times as likely to develop complications
Risk factors for 1-10 days
Total IV anesthesia had 70% lower odds of complications
Not feeding animals until >24 hours 4.5 times greater odds for complications

Question 44

Kerr JSAP 2021

Late onset recurrence of clinical signs after surgery for intervertebral disc extrusion in French bulldogs

Answer 44

84 Frenchies; 55 had TL discs, 29 cervical
51% had recurrence of clinical signs following sx
median time from sx to recurrence was 9mo 21days
conclusion: high rate of recurrence can help to manage owner expectations
most common cervical location was C3-C4, most common TL site was L2-L3
most cases of recurrence were at distant sites
Frenchies predisposed to IVDE at sites b/w L4-L6
Fenestration may not be helpful since recurrence did not always happen in same spinal cord segments ie/ TL dogs may have had recurrence in cervical region

Question 45

Inness VCOT 2021

Distraction stabilization of degenerative lumbosacral stenosis: technique and mid- to long-term outcome in 30 cases

Answer 45

The most common presurgical imaging findings were disc protrusion (24/25) & sclerosis of the caudal end-plate of L7 (23/30).
On short- to long-term assessment- 18 of 21 dogs exhibited clinical improvement & all dogs had improved pain scores (p<0.0001)
8 dogs had complications:
Major complications occurred in 5 dogs, of which 3 required additional sx
Catastrophic complications occurred in 3 dogs
1 died of causes unrelated to sx; 2 were secondary to iliac a. laceration 🡪 internal iliac vessels align w/ implant corridor (w/in 3.4–13.2mm of the vertebral body)
Both catastrophic surgical errors were associated w/ excessive pin insertion (>1cm)
& primary surgeon for both was new to the technique (performed < 3 surgeries).
Mean foraminal width significantly increased 50% long-term (3.3-1.0mm preop to 5-9mm postop, p<0.0001).
Owners were satisfied to extremely satisfied in 15 of 18 cases (…or 15 of 21 cases if including the 3 dogs that died intraop)
16 of 18 dogs were able to return to full activity & remain active >1yr postop
4 dogs were urinary incontinent at dx for a mean of 3-months 🡪 3 of 4 dogs regained continence w/in 1.5-months postop.
Resolution of pain & hind limb weakness was seen in 16 of 21 dogs (or 76%) using the MFS & TSCIS
Similar to previous reports of LS stabilization utilizing the Griffiths Neurological Score
Distraction w/ stabilization significantly increased foraminal size postop (p<0.0001) 🡪 equivalent to an average of 150% of the initial foraminal measurement & maintained this increase for up to 2yrs following sx.
ALL dogs in this study showed improvement in pain in the short & long term, w/ ~86% showing NO pain at >3mo postop.
Previous reports of dorsal laminectomy or pedicle screw-rod stabilization only showed pain resolution in 38-50% of dogs.
Dorsal laminectomy, annulectomy & distraction stabilization w/ pins & PMMA for the management of degenerative LS stenosis resulted in sustained & significant improvement in neurological scores & pain scores at each time point post-op.
It’s a complex procedure but can significantly increase foraminal width, reduce pain & improve gait…but should be performed by surgeons experienced in LS pin placement.
Significant foraminal width enlargement & non-significant reduction in LS step defect (p=0.1585) was maintained for up to 2 yrs postop, which has not been previously reported w/ other LS stabilization of foraminotomy procedures.

Question 46

Bresciani Vet Sx 2021

Lumbosacral intervertebral disk extrusions in 13 dogs

Answer 46

All dogs had acute or subacute onset LS pain and nerve root signature
50% (7/13) had neuro deficits
MRI: lateralized disc material and partial to complete disc herniation in all cases
Extradural disc material extended cranial or caudal in 10/13
This may help differentiate from IVDP
All dogs had dorsal laminectomy and removal of extruded disc material
6 dogs had inflammatory changes including epidural steatitis
outcome excellent in 11 dogs, poor in 2 dog (contralateral nerve root signature (1), nonamb paraparesis and urinary incontinence (1)
conclusion: LS IVDE characterizedby acute or subacute onset of LS pain and nerve root signature. Disc was often lateralized and extended cranial or caudal over degenerate disc site. Early decompression w/ dorsal lam generally led to excellent outcome

Question 47

Pfund JSAP 2022

Postoperative outcome of ambulatory dogs with intervertebral disc extrusion causing incontinence and/or tail dysfunction: 18 cases (2010-2020)

Answer 47

12 (67%) dogs had received medical therapy consisting of a NSAD medication (9 dogs) and/or gabapentin (8 dogs), prednisolone (1 dog; Prednicare, Animalcare) or tramadol (1 dog; Tralieve, Dechra) for a median of 7 days
Neurological exam
10 dogs MFS 4; 6 dogs MFS 5; 2 MFS NA
10 with tail paresis and five with plegia.
Loss of nociception in the tail was recorded in 3 (17%) dogs, each w/ tail plegia.
Low tail carriage and/or reduced to absent tail tone in 7 dogs (39%).
3 dogs had reduced anal tone & 3 dogs had absent anal tone.
4 dogs had a reduced perineal reflex
6 had an absent perineal reflex.
MRI
L5-L6 in 9 dogs (50%), followed by L6-L7 in 4 (22%) dogs, L7-S1 in 4 (22%) dogs and L4-L5 in 1 (6%) dog.
Hemilaminectomy in 78%; dorsal laminectomy 22%
Urinary continence recovered in 86%
Fecal continence recovered in 90%
Tail function recovered in 87%
Loss of tail nociception
2 made full recovery and one showed mild persistent tail paresis

Question 48

Tanoue JAVMA 2022

Postoperative outcomes of combined surgery comprising dorsal laminectomy, transarticular screws, pedicle screws and polymethylmethacrylate for dorsal fixation in 21 dogs with degenerative lumbosacral stenosis

Answer 48

Retrospective review of 21 client owned dogs diagnosed with DLSS and treated surgically.
Reports demonstrate that dorsal laminectomy improves postoperative clinical signs in 69% to 93% of cases in the short term; however, in the long-term, clinical signs recur in 3% to 37% of cases
Based on clinical records, signalments, clinical signs, findings from orthopedic and neurological examinations, imaging findings, and postoperative complications were evaluated at the following time points: preoperatively, postoperatively, and 3, 6, 12, 24, and 36 months after surgery
In all 21 cases, clinical signs were alleviated, proprioceptive deficits were improved from 3 months after surgery, and no recurrence of clinical signs was observed during the observation period.
Minor complications were observed in 6 cases (28.6%), including implant failure in 2 (9.5%), delayed healing of surgical wounds in 2 (9.5%), seroma in 1 (4.8%), and swelling of the affected area in 1 (4.8%).
There was no case with major complications

Question 49

Ros JAVMA 2022

Central cord syndrome: clinical features, etiological diagnosis, and outcome in 74 dogs

Answer 49

2 neuroanatomical locations
C1-C5 88%
C6-T2 12%
Did not correlate with imaging findings in 58%
Main lesions C3-C4 (28%) and C4-C5 (24%)
Diseases
Hansen type I disk herniation 36%
HNPE 22%
Outcome favorable in 93%
14.7 times more likely to have poor outcome in patients with hypoventilation
Surgery performed in 57%

Question 50

Troupel JVIM 2021

Epidemiological, clinical, and electrophysiological findings in dogs and cats with traumatic brachial plexus injury: a retrospective study of 226 cases

Answer 50

46% <2 years, 57% >20 kg
90% dogs and 84% had anesthesia of the radial autonomous zone
89% dogs and 86% cats ulnar zone
67% dogs and 67% cats median zone
41% dogs and 31% cats had musculocutaneous zone
40% and 27% had all of the zones
Radial (not ulnar) compound muscle action potential (CMAP) amplitude for dogs and cats that had clinical improvement was higher than in animals without improvement (4.3 mV vs 0 mV)
>5 mV had a specificity of 93%, sens 47%
>0.73 mV had a spec of 67% and sens 80%
Radial nerve
Ipsilateral absence of cutaneous trunci and abnormal spontaneous EMG in paraspinal muscles associated with decreased CMAP
Positive correlation between time between trauma and EDX and CMAP amplitude, but weak
Ulnar nerve
Weight and ipsilateral absences of cutaneous trunci reflex associated with decreased CMAP

Question 51

Couper JFMS 2020

Evaluation of prognostic factors for return of urinary and defecatory function in cats with sacrocaudal luxation

Answer 51

90% regained voluntary urinary function

Higher neurological grade associated with decreased likelihood and longer duration of regaining urinary function
grade 5 injuries were less likely to regain urinary function than cats with grade 2 (P=0.029) or grade 3 (P=0.022) injuries.
50% of grade 5 regained function
89-100% grade 4-1
87% of cats that regained urinary function doing so within the first 30 days.
Cats that were treated with medication to facilitate urination took significantly longer to recover urinary function than those that were not receiving such medication
Associated with fecal outcome
22% fecally incontinent, 35.8% constipated
10% and 18.8% regained normal fecal function
Cats that regained defecatory function had longer survival than those that did not recovery defecatory function
No significant associations were found between urinary outcome and age, sex, anal tone, perineal sensation, tail base sensation, degree of craniocaudal or dorsoventral sacrocaudal displacement, concurrent orthopaedic injury, tail amputation, defecatory function at diagnosis and survival.

Question 52

Argent JSAP 2022

Recurrence of signs consistent with cervical intervertebral disc extrusion in dogs

Answer 52

Retrospective; 119 dogs with MRI- or CT-confirmed cervical IVDE
Complete recovery was documented following:
Medical (36/119, 30.3%) or
Surgical (83/119, 69.7%) management of initial cervical disc extrusion.
There was recurrence of consistent clinical signs in 40 of 119 (34%) cases…of which:
27 of 83 (33%) were initially managed surgically
13 of 36 (36%) medically
In 24 of 40 (60%) cases, there was imaging confirmation of recurrent extrusion:
Medically managed dogs → recurrence mostly occurred at the same site
Surgery → recurrence most commonly involved an adjacent disc site
Of the 40 recurrences (34% of cases) → 32 (80%) recurred w/in 2 yrs of diagnosis
Rate of recurrence was similar btwn treatment groups in both univariable & multivariable (hazard ratio 1.03; 95% CI: 0.67 to 1.53; P=0.87).
Clinical Significance: Following successful initial medical or surgical treatment, C.S’s consistent w/ recurrent cervical disc extrusion occurred w/ similar frequency. Medically treated cases tended to have recurrence at the same site as initial presentation, whereas surgical treatment prevented this.
Recurrence usually occurred within 2 yrs. However, consider the retrospective study design, small number of recurrences (34%) and lack of imaging confirmation of every recurrence (40% did not have imaging) when interpreting the results.

Question 53

Silva JAVMA 2023

The spinal cord-to-vertebral canal area ratio measured with computed tomography is lower in the thoracolumbar than the cervical region in French Bulldogs

Question 54

Siu JAVMA 2023
No adverse consequences associated with targeting clinical signs to initiate antimicrobial treatment of postoperative subclinical bacteriuria in dogs following surgical decompression of Hansen type I thoracolumbar disk herniation

Answer 54

The study was conducted as a retrospective observational study.
37 French Bulldogs identified
We have observed that the spinal cord is often severely compressed but with minimal accompanying neurologic deficits following intervertebral disk extrusion in the cervical region and that, conversely, the spinal cord can often seem to not be severely compressed following disk extrusion in the thoracolumbar region, even when marked neurologic deficits are seen.
CT images were reviewed, and measurements were performed by 2 investigators.
Measurements of the spinal cord and vertebral canal were made at the level of or immediately cranial to the midbodies of C5 and L1
A 2-tailed, paired t test indicated that the mean spinal cord-to-vertebral canal area ratio differed significantly (P < .01) between C5 (0.726) and L1 (0.605).
The ratio was lower in the thoracolumbar region, suggesting that the vertebral canal was relatively larger in this region.
The reason for the often more severe neurologic deficits observed in dogs with thoracolumbar versus cervical intervertebral disk extrusions remains unclear.
The epidural space did not appear to be larger in the cervical than in the thoracolumbar region in this population of French Bulldogs, contrary to previous reports. The reason for the more severe deficits observed with thoracolumbar disk extrusion in this breed remains to be characterized

Question 55

Lovell JVIM 2022

Randomized clinical trial comparing outcomes after fentanyl or ketamine-dexmedetomidine analgesia in thoracolumbar spinal surgery in dogs

Answer 55

Ketamine blocks N-methly-D-aspartate (NMDA) receptor (neuroprotective), has antiinflammatory effects, decreases the requirement for inhalants, and decreases post-op shivering
Dexmed also has neuroprotective and antiinflammatory effects
Opioids can exacerbate inflammation in the SCI animal (rat study)
Study:
102 dogs undergoing decompressive surgery for TL IVDE
Random clinical trial, 1:! fentanyl or K-D combo for intra and postop
No difference in time to recovery of ambulation was found b/w the 2 groups or in pain scores (Colorado, Glasgow)
Time to recovery for eating and urination were better in K-D > fentanyl, but differences were small

Question 56

Rosen JVIM 2022

A 50-step walking test for analysis of recovery after decompressive surgery for thoracolumbar disc herniation in dogs

Answer 56

Study aimed to validate a new walking test for recovery of ambulation postop from TL IVDE
240 dogs < 20kg (120 normal; 104 decompressive surgery)
Each postop dog was assessed for the 50-step distance completed w/o falling or their INability to complete the distance by 4 mos postop
Control dogs: 50-step distance was (m) = 1.384 x ulnar length (cm) + 2.773
Postop dogs: 50-step test showed definitive evidence that deep pain negative dogs were less likely to recover ambulation than intact pain dogs; and if they did recover, it took much longer (91 vs 14 days)
Presurgical neuro status and duration of anesthesia were associated with rapidness of recovery

Question 57

Mehra JVIM 2023

Double-blinded placebo-controlled clinical trial of prophylactic omeprazole in dogs treated surgically for acute thoracolumbar intervertebral disc extrusion

Answer 57

GI mucosal injury is common in dogs being treated with TL-IVDE (submucosal hemorrhage predominates; in general 76% of TL-IVDE mucosal injuries are identified endoscopically)
Pathogenesis: stress, anesthesia, surgery, imbalance of the ANS, secretion of proteolytic enzymes, subsequent gastroduodenal ulceration; also use of NSAIDs, steroids, opioids
Omeprazole (PPI) irreversibly binds to and inhibits the enzyme responsible for gastric acid secretion, increasing gastric pH

Study
Investigate if short-term use of Omeprazole decreases development of clinical GI signs during postop for acute TL-IVDE
37 post-hemilaminectomy dogs randomized b/w placebo or Omeprazole 1mg/kg q12h x 5 days
GI signs were observed and testing performed at hospitalization, 2 weeks and 4 weeks postop included Fecal Occult Blood (FOB), PCV, BUN/Creat ratio, fecal calprotectin, cPLI, fecal alpha-1 proteinase inhibitor concentrations
10/20 dogs (50%) developed GI signs in the Omeprazole group and 7/17 (41%) in placebo group
Diarrhea most common (40% Omeprazole, 30% Placebo)
Hematochezia rare (5% Omeprazole, ~6% Placebo)
Melana absent in both
Bleeding was present in 45% Omeprazole and 65% Placebo based on clinicopathologic testing
FOB more common in dogs with GI signs; cPLI higher during hospitalization than on rechecks
Conclusion: Short term Omeprazole DID NOT decrease clinically detectable GI complications in dogs with acute TL-IVDE

Question 58

Craciun VCOT 2022

Contrast-Enhanced Low-Field MRI Occasionally Alters the Surgical Approach for Canine Intervertebral Disc Extrusions

Answer 58

Contrast-enhanced MRI has been shown to increase the sensitivity/specificity of MRI for lesions w/in the vertebral canal
Gadolinium-based contrast agents reduce the longitudinal (t1) relaxation time, producing an increased signal (‘positive contrast’) on T1W images w/in tissue in which they have accumulated, these are notably the meninges, hemorrhage, fibrosis, epidural steatitis and neovascularization in the case of IVDE
Study:
To evaluate if addition of contrast on low-field MRI will change the surgical plan for IVDE
Reviewed 20 cases of dogs w/ IVDE and contrast administration
Results:
Contrast enhancement was observed in 17/20 dogs with extradural compressive material
In 14/20, contrast increased the confidence level of surgical location (70%)
In 2/14, the surgical location was changed after contrast was administered (~14%)
Conclusion:
Gadolinium can aid in surgical planning of IVDE dogs by improving confidence level of location and extent of extradural material, and in ~14% of cases, it can alter the surgical approach

Question 59

Balducci JVIM 2017 PQ

Prevalence and Risk Factors for Presumptive Ascending/Descending Myelomalacia in Dogs after Thoracolumbar Intervertebral Disk Herniation

Answer 59

Ascending/descending myelomalacia (ADMM)

13 dogs developed ADMM, with an overall prevalence of 2.0%. The prevalence of ADMM was 0% in dogs with neurological signs graded 1 or 2 at admission or before magnetic resonance imaging (MRI) or surgical procedures, 0.6% in dogs with neurological signs graded 3, 2.7% in dogs with neurological signs graded 4, and 14.5% in dogs with neurological signs graded 5. Age (<5.8 years), neurological status (grade 5), site of disk herniation (L5-L6), duration of clinical signs before becoming nonambulatory (<24 hours), detection of intramedullary T2-weighted (T2W) hyperintensity, and a T2 length ratio >4.57 were significant risk factors in the univariate analysis for development of ADMM.

Conclusions and clinical importance: The factors identified in this study may be useful for the prediction of ADMM. Multicenter studies with a higher number of dogs with ADMM are required to confirm these data.

Question 60

Emery VRU 2018 PQ

Investigation of parameters predicting the need for diagnostic imaging beyond computed tomography in the evaluation of dogs with thoracolumbar myelopathy: Retrospective evaluation of 555 dogs

PQ comparing CT vs CT myelogram and when you’d recommend doing the myelogram

Answer 60

555 dogs were identified in this time frame which underwent CT imaging for myelopathy of the thoracolumbar region. Various parameters including age, gender, sexual status, breed, chronicity, site of lesion, time of study, and contrast administration were evaluated. Findings indicated that 7.6% of dogs needed additional imaging after CT. Dachshunds were less likely to need additional imaging (P = 0.0111) as were patients scanned during normal business hours (P = 0.0075). Increasing age of the patient increased the likelihood of additional imaging (P = 0.0107). Dogs which did not have additional imaging performed were 21.89 times more likely to require surgery than those which did have additional imaging (P < 0.0001). Findings supported the use of CT as a first-line imaging modality for dogs presenting with thoracolumbar myelopathy.

Question 61

Dixon 2017 JAVMA PQ

Effect of anesthesia-associated hypotension on neurologic outcome in dogs undergoing hemilaminectomy because of acute, severe thoracolumbar intervertebral disk herniation: 56 cases (2007-2013)

PQ Anesthesia paper, maybe something about how hypotension during surgery affects outcome after hemilam

Answer 61

33 (59%) patients experienced hypotension during anesthesia. Thirty-four (61%) patients (20/33 with and 14/23 without hypotension) regained ambulation. Whether dogs regained motor or urinary function was not significantly associated with the occurrence of hypotension (P = 0.35 and P = 0.86, respectively), the duration of hypotension (P = 0.213 and P = 0.274), or the lowest blood pressure recorded (P = 0.556 and P = 0.699). CONCLUSIONS AND CLINICAL RELEVANCE For this group of dogs undergoing hemilaminectomy because of acute, severe thoracolumbar IVDH, anesthesia-associated hypotension was not significantly associated with whether dogs regained motor or urinary function after surgery. However, normotension should be the goal in all patients with spinal cord injuries, especially patients undergoing general anesthesia.

Question 62

Fenn JVIM 2021 PQ

Efficacy of hypophysectomy for the treatment of hypersomatotropism-induced diabetes mellitus in 68 cats
85% survived to 4wks, 15% had postop death

PQ % remission of diabetes

Answer 62

complications included: hypoglycemia , electrolyte imbalance and transient CHF
95% of those who survied 4wks (80% overall) had improved DM control

remission occurred in 70% of cats surviving >4wks (60% of all cats)

insulin d/c median 9 days postop
postop 4wk IGF-1 conc nadir was sig lower in cats achieving remission vs those that did not
all cats received long-term levothyroxine ad hydrocortisone, 72% had desmopressin
recurrence in 12% at median 250 days
MST was 850 days

Question 63

Van Bokhorst JVIM 2021

Evaluation of hypophysectomy for treatment of hypersomatotropism in 25 cats

Answer 63

Median postop hospstay was 7 days
1 cat died w/in 4 wks
median GH cocn decreased sig from 50ng/mL to 4ng/mL at 5hrs postop
remissio occurred in 23/24cats (~95%), 22/24 (92%) entered diabetic remission
MST was 1347 days
1yr, 2yr and 3yr survival was 75%, 75%, 50%
conclusion: tx had low death rate, and high % DM remission and definitive care