Spinal injuries Flashcards
How many bones in the spine
33 - 7 cervical, 12 thoracic, 5 lumbar, 5 sacral fused into 1 and 4 coccygeal (usually fused into one)
Discuss the three column model of spinal column and stability
The anterior column - formed by alternating vertebral bodies and IV disks surrounded by the annulus fibrosis capsule and anterior longitudinal ligament
Middle column consists of the posterior part of the annulus fibrosis and posterior vertebral wall
Posterior column consists of the spinous processes, nuchal ligament, interspinous and supraspinous ligaments and ligamentum flavum
Disruption of a single column results in a stable fracture but does not exclude SCI
Disruption of 2 columns results in a fracture that is stable in one direction but unstable in the other ie: stable in flexion but not extension
Disruption of 3 columns leads to multi directional instability.
Discuss flexion injury involving the c1-c2 complex
Can cause an unstable alanto-occiptal or alantoaxial joint dislocation with or without associated fracture of the odontoid. The basion (median point of the anterior portion of the foramen magnem)-axial (BAI) and Basion dens interval are normally less than 12mm. value greater the 12 suggest a dislocation.
Discuss flexion injuries below the level of the c1-c2 complex
flexion injury below the c1-2 complex exerts a stong pull on the nuchal ligament complex which usually remains intact. As such most of the force is expended on the vertebral body anteriorly causing a simple wedge fracture – this is usually a stable fracture. Radiographically there is a diminished height and increased concavity of the anterior border.
With severe flexion forces a teardrop fracture can arise. This is characterised by anterior displacement of a wedge shaped fragment of the anteriorinferior portion of the involved vertebral body– this fracture is usually unstable as both the anterior and posterior ligaments are commonly disrupted
Clay shovelers fractures is isolated to the spinous process and is stable. Due to felxion on the supraspinous ligament resulting in an avulsion fracture . Seen after direct trauma and after deceleration MVCs that result in forced neck flexion
Pure spinal sublaxtion occurs with ligamentous injury only. Begins posteriorly in the nuchal ligament and proceeds anteriorly to involve the other ligmanets. Rarely associated with neurology is potentionally unstble. Any one with horners, lefort 2 or 3, BOS or neck soft tissue injury should have a CTA
Bilateral facet disolocation occurs when a greater force of flexion causes soft tissue disruption to continue anteriorly to the annulus fibrosis of the IV disk and anterior longitudinal ligmanets resulting in extreme instability.
Discuss shear injury to spine
Trauma to the head in an AP direction can result in 3 types of odontoid fracture
1: type 1 above the transverse ligament - usually stable however if traction forces injury the apical or alar ligament they can be potentially unstable.
2: type 2 at the base of the odontoid where it attaches to c2 -
3: Type 3 – base of the odontoid fracture with extension into the lateral masses of C2
Type 1 stable
Type 2 and 3 fractures are unstable
Discuss flexion rotation injury to the spine
Rotatory alantoaxial dislocation is an unstable injury best seen on PEG views or on CT scan.
Unilateral facet dislocation caused by fklexion and rotation are generally stable as the dislocated articular mass is locked in place
Due to the varying shapes of the atricular process different types of felxion rotation injury are seen.
In the cervical region where articular process are small and almost horizontal unilateral facet dislocation in is common.
In the lumbar region in wihc the articular processes are large and nearly vertical unilateral facet joint dislocation is rare – here unilateral or bilateral articular process fracture are more common
Discuss extension injury to the cervical spine
The hangmans fracture or traumatic spondylolysis of C2 occurs when the cervicocranium - (the skull, atlus and axis) is hyperextending as a result of abrupt deceleration. Bilateral fractures of the pedicles of the axis occur without dislocation. Although technically unstable cord damage is not common as the neural has the largest calibre in this region and the bilateral facet joints fractures allow decompression.
Discuss the quebec task force classification of whiplass associated disorders
Grade 0 - whiplash injury but no pain, symptoms or signs
Grade 1 - delayed neck pain, minor stiffness, non focal tenderness only no physcial signs
Grade 2 - early onset of neck pain, focal neck tenderness spasms, stiffness and radiating symptoms
grade 3 - early onset of neck pain, focal neck tenderness spaasm, stiffness radiating symptoms and sifns of neurological deficit
Grade 4 neck complaint (grade 2-3) and fracture dislocation
Discuss neurological evaulation of potential spinal injuries
- Phrenic nerve arrises from c3-4 –> abnormal breathing patterns suggest upper cervical injury
- Presence of horners syndrome suggest disruption of the sympathetic trunk usually between c7-t2
Priapisms occurs with severe SCI and can be an indicator of potentional spinal shock
Should be aware of past medical history – downs predisposes to atlanto- occiptial dislocations, rheumatolgical condition predispose to c2 transverse ligament rupture
Presence of cord mediated deep tendon reflexes can help differentiate from upper and lower neuron aetiology. Loss of reflexes suggest lower motor neuron which could potentially be ameniable to surigcal intervention.
Discuss sensory level examination
If an area of hypesthesia is found one should move the sensory stimulus from areas of decreased sensation outwards as it is easier for the patient to identify the development of sensation rather than the loss.
Levels are as follows c2- occiput c3- thyroid c4- suprasternal notch c5 below clavicle c6 thumb c7 index c8 little finger t4 nipple line t10 umbi l1 femoral pulse l2-3 medial aspect of thigh l4 knee l5 latearl aspect of calf s1 lateral aspect of foot s2-4 perianal region.
Discuss complete spinal cord lesions
A complete spinal cord lesions is defined as total loss of motor and sensation distal to the site of an SCI. Functional recovery is extremely rare if complete cord syndrome persist for more than 24 hours.
Two scenarios need to be considered prior to this diagnosis being made.
1) insurance that there is no evidence of minimal cord sparing such as sacral sparing or intact perianal sensation. – this suggest incomplete cord syndrome normally central cord and can have some recovery
2) spinal shock can mimick complete spinal cord lesion. Results from concussion injury to the pisnal cause that can cause total neurological dysfunction distal to the site of injury. The end of spinal shock is heralded by the return of the bulbocavernous reflex.
Discuss central cord syndrome
most commonly seen in patient with degenerative arthritis and hyperextension injury. The ligmamentum flavum buckles into the cord resulting in a concussion of the central gray matter in the pyramidal and spinothalmic tracts.
Because fibers innervating distal structures are located in the spinal cord periphery the upper extremities are more severaly affected then the lower extremities.
Patients experience greater motor impairment in upper compared with lower extremities, bladder dysfunction, and a variable degree of sensory loss below the level of injury
Discuss Brown-sequad syndrome
Hemisection of the spinal cord usually seen in penetrating trauma but may also be seen after a lateral mass fracture of the c-spine.
Patients with this syndrome have ipsilateral loss of motor function as well as fine touch and vibration - and contralateral loss of pain and temperature sensation.
Because the fibers of the lateral spinal thalamic tract cross at a different level the pain and temperature loss may be found variably one or two segments below the lesion.
Almost universally retain bowel and bladder function and most become ambulatory
Discuss anterior cord syndrome
Results from hyperflexion injury causing cord contusion by the protrusion of bony fragment or herniated dick, or by laceration or thrombosis of the anterior spinal artery,.
Characterised by paralysis and hypalgesia below the level of the injury with preservation of posterior column function including position touch and vibratiojn. – can be potentionally aided with surigcal intervention.
Discuss NEXUS criteria
Decision making rule to exclude need for imaging in c-spine injuries. Need to make 5 criteria
1) nil mid line tenderness
2) nil neurology
3) nil distracting injury
4) normal alertness
5) nil intoxication
Sensitivty 99.6%, specificity 12.9 and NPP 99.8%
34000 patients in study 3.5x greater than CCR
As applied sensitivty 99.6
Subsequent evaluation have found sensitivty to be more variable between 83-100% for CSI
Has been validated for children
