Neurosurgery Flashcards

1
Q

When is spinal decompression surgery indicated?

A
  • Tumour

- IVDD

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2
Q

What are the indications for spinal fusion surgery?

A
  • Instability of the spine: atlanto-axial subluxation, Wobbler (dynamic instability), IVDD
  • Fracture
  • Conditions where ongoing instability may cause ongoing trauma of the spinal cord
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3
Q

Name the surgical options for spinal decompression

A
  • Dorsal laminectomy
  • Hemilaminectomy
  • Ventral slot
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4
Q

What is a dorsal laminectomy?

A

Removal of the roof of vertebra

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5
Q

What is a hemilaminectomy?

A

Removal of the side of vertebra

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6
Q

What is a ventral slot?

A

Drill up through bone to access ventral part of spinal cord

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7
Q

Explain the basic principles of spinal decompressive surgery regarding maintenance of spinal integrity

A
  • Depends on intervertebral disc and 2 articular facet joints (sit above spinal cord except on C1 and C2)
  • Biomechanically can remove one facet joint without expected clinical consequences
  • If damage 2, then may encounter problems of stability as only the disc is holding spine together
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8
Q

what are teh treatment options for spinal fractures?

A
  • Fixation if stability is compromised
  • Decompression if compression is the cause of pathology (e.g. bone fragment of dislocation compressing spinal cord)
  • Conservative therapy if stable
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9
Q

Explain how spinal stability can be assessed based on vertebral compartments

A
  • Vertebra can be divided into 3 compartments
  • Dorsal, middle and ventral
  • Instability determined as more than one compartment being compromised
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10
Q

What is included in the dorsal compartment of vertebrae?

A

Lamina and dorsal ligaments

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11
Q

What is included in the middle compartment of the vertebrae?

A
  • Dorsal longitudinal ligament
  • Dorsal annulus
  • Dorsal portion of vertebral body
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12
Q

What is included in the ventral compartment of the vertebrae?

A
  • Ventral longitudinal ligament
  • Ventral annulus
  • Ventral portion of the vertebral body
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13
Q

Describe the conservative therapy for spinal fracture

A
  • Strict cage rest 5-6 weeks, minimise mobilisation of spine
  • Other management as appropriate: analgesia, bladder management, prevention of bed sores, motivational therapy, physiotherapy as appropriate
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14
Q

Describe the main concern regarding hemilaminectomies in the cervical spine

A
  • Rarely performed in this area
  • Vertebral artery runs in canal through vertebrae C1-6
  • ## Drilling through this would be fatal
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15
Q

Describe the advantages of a hemilaminectomy

A
  • Allows lateral approach to the spinal cord

- Allows exposure ventral to the spinal cord

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16
Q

Describe the disadvantages of a hemilaminectomy

A
  • Requires lateralisation i.e. need to know what side lesion is on, if midline then can perform on either side, but not both
  • Risk of damage to nerve roots/spinal nerves via intervertebral foramina opening
  • Risk of damage to ventral venous plexus
17
Q

Describe the advantages of a dorsal laminectomy

A
  • Useful for bilateral lesions
  • Can be performed anywhere along spine except C1-2
  • Relatively easy soft tissue approach
  • Avoids ventral venous plexus
18
Q

Describe the disadvantages of a dorsal laminectomy

A
  • Width of laminectomy limited by the articular facet joints (varies along spine)
  • Limited exposure lateral and ventral to the spinal cord
  • Deep hole in the thoracic region
  • Only good for lesion on top of, or down both sides of the spinal cord
19
Q

Describe the anatomical basis for a ventral approach to the cervical spinal column

A
  • Through vertebral bodies, centred on the intervertebral disc
  • Need to avoid previous surgical sites for recurring IVDD
  • Easy access if in neck region
  • Drill up through vertebral body to get access to vertebral canal
20
Q

Describe the advantages of a ventral slot surgery

A
  • Allows access to the ventral aspect of the spinal cana

- Easy approach (if know anatomy) down to the bones

21
Q

Describe the disadvantages of the ventral slot surgery

A
  • Limited access, visibility
  • Only feasible in cervical region
  • Significant risk of haemorrhage (may drill through ventral venous plexus)
  • Post operative morbidity
22
Q

Discuss the use of ventral slot surgery in a Doberman

A
  • Common require this surgery
  • can be significant risk as high risk of drilling through ventral venous plexus
  • BUT Doberman also prone to Von Willebrand’s disease
23
Q

What are the internal spinal fixation options?

A
  • Orthopaedic procedures e.g. plates

- Pins and methylmethacrylate

24
Q

What are the external spinal fixation options?

A

Spinal casting only

25
Q

Discuss external fixation of the spine using spinal casting

A
  • For relatively stable fractures in good alignment
  • Plaster cast immobilises bones enough to allow natural healing of bones
  • More simple, more natural vs internal fix.
  • U shaped casts, strapped on
  • More expensive long term due to nursing requirements
  • Difficult to do successfully
  • Cervical stabilisation easier than thoracolumbar
26
Q

What are the main disadvantages of spinal casting?

A
  • High nursing requirement: urination, frequent bandage changes, sores likely to develop under bandage as dog walks
  • Sedation for each bandage change
  • Risk of tracheal/oesophageal occlusion with cervical casts, post op swelling can then prove fatal
27
Q

Outline the requirements for post-operative management of a tetraplegic/paretic or paraparetic/plegic patient

A
  • Empty bladder
  • Analgesia
  • Cage rest
  • Physiotherapy
  • Food
28
Q

Discuss the use of physiotherapy post-operatively for spinal treatment

A
  • Which type depends on pathological processing occurring
  • E.g. hydrotherapy poor choice for unstable spine
  • If stable, want to get limbs moving asap
  • Need to ensure dog is able to see/go outside at least once a day
29
Q

Discuss the anaesthesia for spinal injury patients

A
  • Intrinsically nothing special
  • Care re. blood pressure
  • Reduction in blood pressure leads to reduced perfusion of the spinal cord and brain, needs to be maintained
  • Reduced blood pressure leads to avascular necrosis of the spinal cord which leads to worse outcome and potential absence of recovery
30
Q

Discuss the use of steorids in spinal injury patients

A
  • Contraindicated in acute cases

- May be useful in chronic cases

31
Q

Outline the principles of intracranial surgery

A
  • Feasible in some circumstances e.g. large tumour removal
  • Will inevitably cause iatrogenic intracranial trauma
  • Anaesthesia requires careful control and consideration of ICP