Vertebral fractures Flashcards
Is absent nociception associated with a worse prognosis for patients with IVDH or vertebral fracture?
Vertebral fracture, luxation or subluxation. Only 12% of dogs in one study regained ambulation.
What is associated with a negative outcome in dogs with vertebral fracture/luxation based on radiographs?
Degree of dislocation
What parts of the vertebral canal is radiography particularly poor at evaluation?
The dorsal and middle compartments
What are the anatomic classifications in the three compartment model of vertebral stability?
Dorsal, middle and ventral. If more than one of these compartments is compromised the vertebral column is considered unstable and surgical intervention is recommended
What are the three principle contributors to vertebral instability as per the simpler classification model of vertebral stability?
Intervertebral disc: primarily responsible for rotational stability, also involved in lateral bending. Vertebral body may provide some buttressing in bending if still intact with disc injury.
Vertebral body: bending forces and axial compression. Fracture of the vertebral body alone is likely to be very unstable.
Articular process: resists all forces. Isolated fracture of one articular process may not result in vertebral instability.
Injury to more than one of these compartments should be considered unstable.
Describe a treatment algorithm for vertebral fractures/luxations
Has the use of corticosteroids been shown to improve outcomes following vertebral fracture/luxation?
No
Which patients are the best candidates for external coaptation?
Small patients with minimal neurologic function, intact ventral buttress and lack of concurrent thoracic, abdominal or pelvic injuries
When external coaptation is used for treatment of vertebral fracture/luxation what is the extent of splint material that is required for stability?
Lumbar: should include whole pelvis
Cervical: should go to level of eyes (to stabilize the atlanto-occiptal joint) and midthorax
What are the main vascular structures that are at risk during pin placement for vertebral fracture stabilization?
The azygous lies just ventral to the right thoracic vertebral column (often within 1mm of vertebral body). Aorta, pleura and lung are also in close proximity to thoracic vertebrae. In the lumbar vertebrae these structures are somewhat protected by the presence of the hypaxial muscles.
What are the ideal pin insertion angles for TL vertebral stabilization?
If bleeding is encountered during drilling of the pilot hole for pin placement in TL vertebral stabilization what structures might be responsible?
Might be penetration of vertebral venous plexus, or damage to the centrally located basivertebral veins
What diameter should pins be limited to for TL vertebral stabilization?
20-25% of the diameter of the vertebral body
How many pins are required to provide adequate stabilization of a TL vertebral fracture/luxation?
4 pins and PMMA shown to have equivocal stiffness in extension, flexion and rotation as the intact vertebral column in biomechanical testing
What surgical techniques are primarily used for TL vertebral fracture/luxation stabilization?
Pins PMMA, ex-fix, locking plates (SOP most frequent, lateral LCP described). These techniques can all be used with compromised integrity of two or more vertebral column compartments
What are the main differences between cervical and thoracolumbar stabilization?
Ventral approach for cervical stabilization. Cervical pedicles are narrow and transverse processes have transverse foramina that contain the vertebral arteries, veins and nerves. This makes safe passage of implants challenging. Pin insertion angles are varied and should be determined based off CT pre-op
What is the most common imaging presentation of LS fracture/luxation?
Cranioventral sacral displacement with small caudoventral wedge fracture of the L7 body
