Spinal Cord Injury Test 3 Flashcards
Spinal Cord Injury
cord be a zone of injury where nerves/spinal cord of different levels are affected
Pathophysiology of SCI
- physical alteration of cord /cutting of cord fibers
- cord intact w/ auto-destructive process (result of a force of injury
- cord intact with vascular compromise
- Traumatic or Non-Traumatic
Non traumatic Etiology
- vascular malformations
- aneurism, thrombus, embolus, arterial venous malformation (no capillaries)
- vertebral degeneration and subluxation
- osteoporosis, severe kyphosis, RA, kyphoscoliosis, stenosis, Paget’s disease, AA dislocations
- Primary or secondary neoplasms(cancer)
- multiple myleoma , myeloma, metastases from breast or lung
- infections
- myelitis, syphillis, Gulian -Barre
- abscess(collection of pus)
- necrosis of tissue
- congenital defect
- spinia bifida
- other
- myelopathy secondary to radiation therapy, MS, ALS, syringomyelia
Traumatic etiology
- sports (12%)
- violence(16%)
- falls(22%)
- MVA (46%)
Incidence of SCI
- 20-60 new cases /million persons (average 40/ million)
- 11,000 new cases/yr
- *6-8 cases/million ppl die before they get to the hospital each yr
Prevalence of SCI
- over 200,000 individuals in US
- 225,000-296,000
- 80% of all traumatic cases are male (77.8% of SCI since 2000 occurred in males)
- over half of all SCI cases are between ages 15-30 y/o
- since 2000 11.5% of SCI have occurred in those 60+y/o
MOI
Factors which affect vertebral injury
- direction of force applied to system
- position of the person’s head at time of injury
- magnitude, rate of application and duration of injuring forces
- point of application
- infer forces from history of accident and pattern of vertebral and lig. injury
MOI of C spine
- poor stability, designed for mobility (increased risk of injury)
- 40% incidence in spinal cord injury w/ damage to Cervical vertebrae
- 52% of SCI occur in cervical region
- three most common damaging forces are; flexion, vertical loading, and extension
Hyperflexion MOI in C-spine
- head collision in which head strikes steering wheel or windshield
- blow to the back of the head, fall on the back of the head
- compression anteriorly, distraction posteriorly
- C5-C7
- wedge fx of vertebral body , tearing of posterior lig.,anterior dislocation of vertebral body, disruption of disc, fx of posterior structures(SP, laminae,pedicles)
- *note in spine generally 50% of SCI are due to excessive flexion as MOI
flexion with rotation MOI in C spine
- often seen with lateral flexion
- often results in dislocation and locking of a single facet joint
- may also present with fx of lamina or pedicle
- often stable situation
- neurologic damage; Brown sequard (hemisection of cord), nerve roots
vertical compression /axial loading MOI in Cspine
-high velocity blow to the top of the head
-often have burst fx (comminuted)
-fx fragments may migrate posteriorly and enter spinal canal and lodge in cord
-rupture of disc
-occurs most frequently at C4-C5 resulting in complete quadriplegia
(may occur with near drowning)
hyperextension MOI in cervical spine
- strong posterior force-rear end collision, fall and hit chin or forehead
- distraction anteriorly, compression posteriorly
- fractures of posterior structures; SP, laminae, facets
- avulsion fx of anterior aspect of vertebrae
- anterior structures torn
- rupture or disruption of disc
- C4-C5 most common location
MOI for SCI in thoracic
-t-spine is much more stable than C-spine
(rib cage T1-T10)
-T spine injuries most commonly caused by GSW(gunshot wound), MVA, falls
-T12-L1 most commonly injured
MOI in thoracic spine
Flexion:
-wedge fx:most common
-posterior lig complex may be damaged due to distractive forces (severe)
Vertical Compression
- burst fx bone fragments into spinal cord
*thoracic spine not usually injured by isolated extension or lateral flexion forces
Flexion-rotation MOI for Lumbar SCI
- posterior to anterior force directed at rotated vertebral column
- typically causes fx-dislocation
- posterior lig complex is ruptured accompanied by vertebral body fx(s)
- result: highly unstable injury
Flexion -Distraction MOI for Lumbar SCI
(chance fx)
- often result from use of lap belt without shldr restraint
- lap belt( back seat) becomes a pivot point (fulcrum)
- have flexion -distraction forces from that point
- bony fxs and lig tears are horizontally oriented
- injury in thoracolumbar area
- may also have severe internal injuries
Penetrating wound MOI SCI
low velocity;
-knife, ice pick, low velocity bullets-spinal cord physically cut
high velocity;
- high powered rifles, explosion( does not have to penetrate spine or spinal cord to cause damage to neural structures-concussive forces)
Diagnosis
Radiographs
- C-spine:lateral radiograph
- rapid and effective at dx w/ 85% accuracy
- add open mouth and AP radiograph - almost100% accuracy
- CT:
- gives valuable information on impingement on neuronal canal as well as bony limits of spinal canal
- Myelography
- rarely used alone, may be in conjunction with CT or MRI (may be contraindicated early on bc increases fluid in system which could cause more damage)
- MRI
- appropriate imaging tech for visualizing the necessary tissues however in acute SCI other equipment in the surrounding area my limit its use ( doesn’t expose pt to repeated radiation)
Pathophysiology
- concussion:
- forces applied near cord
- contusion:
- brusied, contact w/ vertebral column, hyperflexion/ext causing brusing
- laceration:
- by object or bony object or tissue
- ascending sensory tracts
- descending motor tracts
- anterior horn cells, spinal nerves, descending tract damage
- initially flaccid-> spasticity increasing over time
- involevment of other systems
- ANS
- Integument
- CV
- respiratory; innervation of diaphragm/ unable to clear secretions
- Bowel/Bladder function
- sexual function
- MS
Classification of SCI
- functional
- extent of injury
- level of injury
Functional classification
Quadriplegia: -all four extremities and trunk are involved -visceral mm also involved -cervical cord -paresis=incomplete -plegia= complete Paraplegia: -lower extremity and trunk involvement -thoracic , lumbar and sacral cord injury - visceral involvement
Extent of injury
Complete:
- all motor and sensory function are lost below the level of the injury
Incomplete:
- an injury is classified as incomplete if there is any function below the level of injury
-preservation of some sensory/motor function below the level of injury
Classification of incomplete injuries
- anterior cord syndrome
- posterior cord syndrome
- central cord syndrome
- brown-sequard syndrome( hemisection)
- sacral sparing
- cauda equina injury (LMN vs UMN)
Extent of injuries
consider:
- UMN/LMN lesion:
- conus medularis, cauda equina
- zone of injury
- includes cord structures, tracts, bony structures, nerve roots