Ancillary Thoracolumbar Spinal Conditions Flashcards
Define ANNPE
Acute Non-Compressive Nucleus Pulposus Extrusion
What type of breed with Acute Non-Compressive Nucleus Pulposus Extrusion seen in?
non-chondrodystrophic dogs
What does ANNPE a result of?
changes in the spinal cord secondary to an acute impact of extruded disc material following an episode of strenuous exercise
ANNPE:
A) What is the disc material?
B) Is there spinal cord compression?
A) Non degenerate
B) No significant
What can be present with ANNPE which can cause mild, non-significant spinal cord compression?
Epidural haemorrhage
ANNPE:
A) Onset?
B) Progressive?
A) Per acute
B) Non progressive
T or F
With ANNPE; pain is a common feature
False
T or F
With ANNPE; clinical signs tend t o be lateralised?
True
What will be the imaging modality of choice to make a diagnosis of ANNPE.
MRI
MRI is imaging of choice with ANNPE, what may myelogrpahy and CT-myelography exclude?
Extradural spinal cord compression
ANNPE; how does neuro grade correlate with management?
The worse the neurological grade the more challenging it is to manage these cases.
With ANNPE; Which lesions carry a worse prognosis?
LMN
Ischaemic myelopathy, also called?
fibrocartilaginous embolism (FCE)
What breed is ischaemic myelopathy seen in?
young, large, non-chondrodystrophic dogs.
What small breed is predisposed to ischaemic myelopathy?
Schnauzer
Pathophysiology of ischaemic myelopathy?
The blood supply to a focal area of the spinal cord is suddenly disrupted leading to ischaemia.
Ischaemic myelopathy:
A) Onset?
Peracute
With ischaemic myelopathy they do not tend to progress further within what period?
First 24 hours
Are patients with ischaemic myelopathy; are they painful, what is hard to assess?
No; difficult to assess pain vs distress
What do the severity of clinical signs of ischaemic myelopathy depend on?
Degree of spinal cord ischaemia
Ischaemic myelopathy; signs a most commonly…?
Lateralised
What determines prognosis with lesion localisation with ischaemic myelopathy?
UMN vs LMN
Ischaemic Myelopathy imaging?
MRI.
(myelography or CT-myelography can be used to exclude extradural spinal cord compressions)
Ischaemic Myelopathy; whar does treatment depend on?
Neuro status
general treatment of Ischaemic Myelopathy?
Supportive
Ischaemic Myelopathy; In cases where the patient is non-ambulatory,
What treatment? (6)
sling support,
boots to prevent trauma to the digits,
regular turning,
soft bedding
bladder management
Physio/hydro
Ischaemic Myelopathy;
What factors influence prognosis?
- Extent of the lesions identified on MRI
- The neurologic score at time of presentation
- Localisation (lower motor neuron lesions) and symmetry of signs also influence the prognosis.
What nociception with FCE is associated with a poorer outcome?
Lack of
FCE; with schnauzers vs large breed. Which have a higher mortality?
Large breed
What longterm effects are possible with FCE?
Residual deficits
Bacterial infection of the CNS is uncommon and can be seen secondary to? (5)
extension of a paraspinal abscess,
migrating foreign body,
haematogenous spread,
bite wounds
iatrogenic
Spinal Empyema; clinical signs? (3)
pyrexia,
spinal hyperaesthesia
deficits related to spinal cord compression (either paresis or plegia).
Spinal Empyema; how to diagnose?
advanced imaging and in certain cases confirmation is achieved during surgery.
Spinal Empyema; What may be revealed on CSF? (3)
abnormal inflammatory cell counts
increased protein levels
can also be normal.
Which of the following statements are true with spinal empyema?
Medical treatment only is not advised.
Treatment can be either medical or surgical.
If medical treatment fails, surgical management with decompressive surgery sampling and lavage should be considered.
Treatment can be either medical or surgical.
If medical treatment fails, surgical management with decompressive surgery sampling and lavage should be considered.
What is medical management with spinal empyema?
4 to 8 weeks course of antibiotics
What is surgical management of spinal empyema? (3)
decompressive surgery, sampling and lavage
With spinal empyema, if there is evidence of marked spinal cord compression and severe neurological dysfunction, what is the advised treatment? (3)
Aggressive surgical decompression and drainage, in combination with appropriate antibiotic therapy (based on culture and sensitivity results)
Where do spinal # most commonly occur? (2)
Thoracolumbar
Cervical spine
Common causes of spinal #? (4)
RTA ** Most common
Bites
Fights
Gunshots
CARE with spinal #; why?
avoid additional injury in cases with vertebral instability.
A thorough exam is needed with spinal #; why? (2)
Establish the origin of the clinical signs and associated injuries
Clinical signs of spinal #.
pain only to para / tetraplegia.
Is the following a surgical candidate?
A patient suffering from a thoracolumbar facture/luxation and being presented as grade V (paraplegia without nociception)
No
Diagnosis of spinal #?
Radiograhy - orthogonal
CT
MRI
Imaging of choice for spinal # surgical planning?
CT
With spinal #, what other area needs to be x-rayed?
Chest
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Interspinois lig.
Dorsal
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Articular facets/joint capsule
Dorsal
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Vertebral lamina/pedicles
Dorsal
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Supraspinous lig.
Dorsal
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Dorsal longitudinal lig.
Ventral
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Ventral longitudinal lig.
Ventral
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Intertransverse ligament
Ventral
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Intevertebral disc
Ventral
Structures that provide strength in the normal vertebral column may be divided into dorsal and ventral compartments.
What is the following:
Vertebral body
Ventral
What are the three most important contributors to vertebral stability?
The vertebral bodies,
The intervertebral discs
The articular facets
What leads to vertebral instability regardless of the degree of displacement seen on imaging?
Failure of more than one of the 3 key components; The vertebral bodies,
The intervertebral discs
The articular facets
When should conservative management be AVOIDED for spinal #?
If the vertebral fracture/luxation is considered unstable as further spinal cord injury may occur.
Spinal #; preferred technique and why?
Utilise the vertebral bodies (ventral compartment) are generally preferred since the dorsal compartment structures are inherently weak and implant failure is not unusual;
What fixation techniques are used for spinal #? (3)
vertebral body screws or pins
cement
vertebral body plates
Why are Surgical techniques using screws (or pins) and bone cement are most versatile?
Placement of implants into the vertebral bodies is not dictated by the holes of a plate.
Benefit of bi-cortical fixation over uni-cortical fixation?
More strength
What screws are advised for spinal #? Why?
Locking screws with cement are preferable to cortical screws with an equivalent thread diameter since their strength is greatly increased by a larger core diameter.
If pins are needed for spinal #, pre drill. Why? (3)
minimise thermal necrosis of bone
Minimise microfractures
Accurate measure depth of vertebral body
What pin type for spinal #?
Threaded
How to increase the implant-cement interface with spinal #?
Pin bending
What cement for spinal #? cf to other preparations when moulding around spinal implants
Polymethylmethacrylate (PMMA) bone cement with a short liquid phase and long dough phase
What plates may be advantageous compared to conventional plates in the thoracolumbar spine because they “stand-off” the vertebrae and interfere less with regional spinal nerves.?
Locking plates with fixed angle screws
In the cervical spine fixed angle screws have a tendency to loosen by? (discuss their insertion)
slicing through the bone since they are generally placed in a uni-cortical manner to minimise the possibility of entering the vertebral canal or transverse foramina
A limitation is that the screw insertion angle is generally determined by?
the plate
Conservative management with spinal #?
4-6 weeks of strict rest with or without a cast
What rate is higher with surgical repair cf to medical?
mortality
Benefit of surgical vs medical with spinal #?
Good prognosis if survives.
What were associated with a poorer outcome with spinal # surgery? (2)
Severity of neurological deficits and a prolonged interval (five days or longer) from trauma to referral
