Neuro: Spinal Cord Injury

Hangman's Fx

bilateral fracture of pedicles of axis (C2) Due to rapid acceleration/deceleration injury (chin on dashboard) 3 types (1-3) Usually non surgical treatment for Type I, but surgery is Usually required for Type II and III

Nociceptive Pain

-musculoskeletal (bone, joint, posture, overuse) -visceral (renal calculi, bowel, dyreflexia headache)

Bowel and Bladder Dysfunction

. Loss of voluntary control of bowel and bladder b. UMN lesions result in spastic bowel and bladder c. LMN lesion results in flaccid bowel and bladder (more incontinence) d. Training programs with UMN can result in effective bowel and bladder management using reflexes for emptying e. Training program for LMN dysfunction less effective due to flaccid sphincters

Mechanisms of Injury- Flexion-Rotation

1. Posterior to anterior force with vertebral column rotated 2. Fracture: posterior pedicles, facets, lamina (very unstable) 3. Associated injuries: Rupture posterior ligaments, subluxation or dislocation of facets (jumping)

Mechanisms of Injury- Hyperextension

1. Strong posterior force, or fall with chin in fixed position (elderly) 2. Seen almost always in cervical region 3. Fractures: posterior elements 4. Associated injuries: ALL rupture, disk rupture

Mechanisms of Injury- Flexion

1. Usually involves C4 to C7 and T12 to L2 due to increased mobility 2. Most common mechanism of injury 3. Fractures: wedge fracture of anterior vertebral body 4. Associated injuries: Fractures of posterior elements, anterior dislocation, disc disruption, facet jumping

Mechanisms of Injury-Compression

1. Vertical force (associated with flexion injuries) 2. Fracture: of endplate, burst fracture 3. Associated injuries: bone fragments in cord, rupture of disc

American Spinal Injury Association (ASIA) Impairment Scale

A = Complete: no motor or sensory function below the level of lesion including S4-S5. B = Incomplete: Sensory but not motor function below level of lesion including sacral segment S4-S5 Note: ANY sensory or motor function in anal region (S4 and 5) makes it an incomplete injury. C = Incomplete: Motor function is preserved below the level of the lesion and more than half of the key muscles below the lesion level have a muscle grade of less than 3. D = Incomplete: Motor function is preserved below the level of the lesion and at least half of the key muscles below the lesion have a muscle grade of 3 or better. E = Normal: motor and sensory function is normal. ASIA E is only assigned as a follow up grade. If the individual has no impairments at time of intial testing, the ASIA scale does not apply.

"Complete" vs. "Incomplete"

A complete lesion presents with no motor or sensory function below the designated lesion level. Caused by complete transection, severe contusion or extensive vascular impairment to the spinal cord An incomplete lesion presents with some sensation or motor function (below a grade of 3) below the designated level of lesion Most often results from contusions. Also from edema and partial transections Prognosis varies, but some recovery possible Asymmetric Injuries With oblique injuries to the spinal cord there may be different functional levels on each side. Need to score each side separately

Incidence of Spinal Cord Injury

A. General Categories: traumatic and non-traumatic 1. traumatic has the higher incidence 2. Non-traumatic vascular tumor infections autoimmune - transverse myelitis spondylosis/ spinal stenosis developmental disorders (meningomyeloceole) B. Incidence of Traumatic SCI: 12,000 new cases/yr U.S. MVA total = 47.5% (40-50%) Automobiles 38% Motorcycle 7% Other vehicles 1% Jumps and falls = 22.9% (leading cause in > 65 y.o.a.) Violence, mostly gunshot wounds = 13.8% (10-25%) Sports = 9% (10-25%) Work related (10-25%) Prevalence ~ 240,000 in U.S. D. Incidence by other factors Gender: Male 80-85% Female 15-20% Age: 15-24 y.o.a. 50% <40 80% >60 11.5% (increasing)

Incidence by Severity of Injury

ASIA A - 45% - complete ASIA B - 15% ASIA C - 10% ASIA D - 30% 40 years ago about 2/3 of injuries were complete injuries Recent trends show most injuries now are incomplete due to several improvements in safety standards (air bags) and medical management. 40% are contusion injuries 61% of clinically complete (ASIA A) are anatomically incomplete Thoracic level injuries most often produce complete injuries when compared to cervical or lumbar.

What arteries supply the spinal cord?

Anterior spinal artery supplies anterior 2/3rds and the core Posterior spinal artery supplies posterior 1/3rd

Cauda Equina Injuries

Burst fracture below L1(below conus) More than one nerve root usually involved. Differentially diagnose from lamina or pedicle fracture, or jumped facet, or herniated disc. Which would involve one root. Usually not all nerve roots involved. Peripheral nerve injuries so can regenerate but still is not likely to be complete

Incidence SCI by level

Cervical 55% Upper C-spine injury more common in children due to fact that head represents higher proportion of body weight Thoracic 15% Thoraco-lumbar 15% Lumbo-sacral 15%

What is the result of damage to the cauda equina?

Descending collection of dorsal and ventral nerve rootlets and therefore damage here results in lower motor neuron lesion

Jefferson Fracture (C1)

Fx of Anterior and posterior arches of C1 From hyperextension most often

Mechanisms of Injury-Shearing

Horizontal force 2. Most frequent in the thoracolumbar region 3. Associated injuries: dislocation

Sacral Sparing

Incomplete lesion where the most peripherally located sacral fibers are spared. Presents with perianal sensation, rectal sphincter contraction, contraction of toe flexors.

Predicting Ambulatory Capacity Post-injury

Motor and sensory ASIA score predict ambulatory capacity See PP table Presence of light touch and pin prick acutely post-injury is correlated with walking at 6 months Indicates that lateral white matter is spared In the acute situation, sparing of sensation to pin prick in a motor segment w/ MMT grade 0 indicates an 85% chance of motor recovery to at least grade 3. If still rated as ASIA A at 1 month, chances of walking are very poor.

Post-traumatic Syringomyelia (Cystic Myelopathy)

Occurs in 3-4% of traumatic SCI b. Onset 1 month to 45 years after injury c. Cavitation of the central canal -associated with liquefaction of intraparenchyemal hematoma -cavity expands due to disrupted CSF flow out of cyst -also associated with tethered cord cord adheres to dura d. Signs and Symptoms -chronic pain -weakness -loss of function -decreased respiratory function -increased or decreased spasticity e. Treatment - shunt to relieve CSF pressure -laminectomy to decompress cord -release of tethering

C2 Fratures

Odontoid Fx's Type I -avulsion of tip of odontoid (least common) -difficult to detect Type II -fracture through base of dens (most common) -complication: nonunion Type III -subdental injury -prognosis: good

Anterior Cord Syndrome

Often caused by disc herniation with severe flexion injury and by damage to anterior spinal arteries resulting in anterior cord damage Characterized by loss of motor function and loss of pain and temperature, but preservation of proprioception, kinesthesia and vibratory sense.

Conus Medullaris Syndrome

Possible with trauma at L1, L2 levels or thoraco-lumbar junction. Most common mechanism is seat belt injury. Vertebra can retropulse, shear or burst or compression fracture. Results in a combination of UMN and LMN lesion. UMN deficits in sacrally innervated muscles and urologic dysfunction. LMN lesion to nerve roots passing by that level (lumbar). Amount of deficit depends on how low the conus goes in that particular person.

Central Cord Syndrome

Related to congenital or degenerative narrowing of spinal canal. Seen most often in the elderly. May only involve pain and temperature crossing fibers creating a "cape-like" sensory loss (C5-6 sensory loss) C5-6 most common levels to have this because most flexion/ext there, the sensory loss pattern will show you which level the cavitation is at If motor tracts involved, usually the lasting deficit is in the UE tracts (LE fibers tend to be more peripheral in white matter) Good prognosis especially with decompression surgery

How many nerve roots exit the spinal cord?

Spinal cord has 31 (33) segments or levels, each of which has a pair of spinal nerves associated with it. 1-3 coccygeal nerve roots depending on the person

Quadriplegia (tetraplegia)

Tetraplegia (Quadriplegia) partial or complete paralysis of all 4 extremities and trunk as a result of cervical level injury

Designation of Lesion Level

The most common method of designating lesion level is to indicate the most distal functioning spinal cord level, as indicated by functioning dermatome and myotome. "Functioning" indicates that the myotomal muscles groups have at least a MMT grade of 3. (Normal strength is not a criterion).

What level does the spinal cord end at?

The spinal cord ends at level of L1-L2 interspace as the conus medullaris

Root Escape

There may be nerve root damage at or near the level of the injury. "Root escape" refers to recovery of function of the damage n. root.

Brown-Sequard Syndrome

Unilateral lesion (often incomplete) of spinal cord resulting usually from stab wound Loss of motor and proprioception on the same side of the lesion beginning at the level of the lesion (Motor because pyramids decussate at caudal medulla and thus supply the CS tracts that in the spinal cord supply ipsilateral side. Proprio because dorsal column neurons don't decussate until they reach the fasiculus gracilis and cuneatus (beginning of medial lemniscus system) in caudal medulla. Loss of pain and temperature on contralateral side beginning a few dermatomes below the level of the lesion. (Spino- thalamic, tectal, and reticular fibers of the anterolateral system may ascend a few levels before crossing.)

Posterior Cord Syndrome

Very rare. Can result from posterior spinal artery damage Presents with loss of proprioception, kinesthesia and vibratory sense

Neuropathic Pain (sharp, shooting, burning, electric, hyperesthsia)

a. Below level of injury -resistant to treatment - major complication after injury - often presents as allodynia -occurs 26% overall SCI pts but up to 58% in older patients b. At level of Injury In dermatome N root compression Cauda equina, syringomyelia c. Above level of injury Compressive neuropathies related to posture or overuse Complex regional pain syndrome

Autonomic Dysreflexia

a. occurs in 48-85% of those with injury above T6 b. unregulated splanchnic reflexes c. Most commonly caused by bowel or bladder stim d. Drastic increases in systemic blood pressure, bradycardia, headache, sweating, increased spasticity e. medical emergency; relieve blockage of catheter, change pt. Position

dorsal and ventral roots

dorsal- afferent, sensory (DRG contains cell bodies) Ventral- efferent, motor join together to form mixed spinal nerve

Paraplegia

partial or complete paralysis of all or part of the trunk and both LE