Epidemiology
National Spinal Cord Injury Statistical Center (2021) Facts and figures at a glance
- road traffic accident 40%
- falls 30%
- sports 10%
Chen et al Arch Phys Med Rehab 2016
- 80% male
- cervical (60%), thoracic (30%), lumbar (10%)
van der Berg et al Neuroepidemiology 2010
- bimodal age distribution
- 15 - 29 - motor vehicle accidents and sports
- > 50 - falls
Natural History
Khorasanizadeh et al J Neurosurg Spine 2019
- systematic review of 114 studies
- improvement of one ASIA grade
- grade A: 19%
- grade B: 74%
- grade C: 87%
- grade D: 47%
Mechanism of injury
Primary
- mechanical
- contusion / compression / stretch / laceration
Secondary
- ischemia
- pro-inflammatory state
- additional neuronal death
- microcystic cavitations
Definition
Neurological level
- lowest level at which motor and sensory function is normal
Complete lesion / no sacral sparing
- absence of sensory and motor function in the lowest sacral segment
- no sacral sparing
Incomplete lesion / sacral sparing
- presence of sacral and motor function in the lowest sacral segment
- indicates preserved function below the defined neurological level
Spinal shock
Refers to initial flaccid paralysis of all motor, sensory and reflexes absent below level of injury
An accurate assessment of spinal cord function can only be made when spinal shock has resolved (48 hrs in 99%)
Resolution of spinal shock
- return of cord mediated reflexes below the anatomic level of the injury
- bulbocavernosus reflex is the lowest and thus the first to return
Bulbocavernosus Reflex
- squeeze glans / clitoris or pull on urinary catheter
- causes anal contracture
- if present indicates S2-S4 region firing
- spinal shock resolved
- can prognosticate about level of neurological injury
Spinal Cord Injury Grading
Medical Research Council (MRC) Power Grading
0 - no visible movement
1 - palpable or visible contraction
2 - active movement with gravity eliminated
3 - active movement against gravity
4 - active movement against some resistance
5 - active movement against full resistance
ASIA Myotomes/Dermatomes (American Spinal Injury Association)
| Upper Limb | Motor | Sensation | Lower Limb | Motor | Sensation |
|---|---|---|---|---|---|
| C5 | Elbow flexor | Lateral arm | L1 | Inguinal ligament | |
| C6 | Wrist extension | Dorsal thumb | L2 | Hip flexion | Middle medial thigh |
| C7 | Elbow extension | Dorsum middle finger | L3 | Knee extension | Anterior knee |
| C8 | Finger flexion | Dorsum little finger | L4 | Ankle dorsiflexion | Medial malleous |
| T1 | Interossei | Medial arm sensation | L5 | Toe extension | First webspace |
| T2 | Armpit sensation | S1 | Ankle plantarflexion | Heel | |
| S2 | Back of knee |
Sensory Levels
T4 - nipple
T7 - xiphisternum
T10 - umbilicus
T12 - groin
American Spinal Injury Association Impairment Scale (AIS)
A (complete): no motor or sensory
B (incomplete): no motor, some sensory intact
C (incomplete): > 50% muscle groups strength < grade 3
D (incomplete): > 50% muscle groups strength > grade 3
E (normal) motor and sensory
Reflexes
Cremasteric Reflex T12-L1
- stroke thigh & scrotal contraction
Anal Wink S2-4
- stroke cleft for anal contract
Babinski
- upgoing = upper motor neuron injury
Oppenheim
- stroke tibial crest & toes go up