Spine Flashcards
What is mechanism and deficit of central cord syndrome
Best prognosis of incomplete SCI
Associated with spondylosis and hyper extension
Injury due to osteophytes and flavum or from haematoma.
Weakness - upper > lower, distal > proximal
Variable
Sensory loss
Loss of bladder and bowel
Sacral sparing.
What is the mechanism and deficit of anterior cord syndrome?
Worst prognosis of incomplete syndromes
Flexion and compression injury affecting anterior cervical artery.
Loss of lateral and ventral Spinothalamic and Corticospinal - pain, temp, light touch. Paralysis lower> upper
Maintain proprioception, vibration and gross touch.
10-20% chance of motor recovery
Causes of Lunbar spinal stenosis
Congenital - short pedicels, failure of formation of posterior elements.
Idiopathic, achondroplasia, osteopetrosis
Acquired DDD/spondylolisthesis Inflammatory Neoplastic Traumatic Iatrogenic - laminectomy
Definition of Schuermann’s
Structural rigid kyphosis of the thoracic Spine defined as anterior wedging of 3 or more adjacent vertebrae with at least 5 degrees
(Sorenson criteria)
Non operative indications for thoracolumbar fractures
<25 degrees kyphosis
Based on stability of PLC
Compression - TLSO 6-12 weeks
Burst - 6 weeks bed rest and 6 weeks TLSO
Bony chance with no PLC injury - TLSO 12 weeks
What is the distribution of MSD?
Lumbar > thoracic > cervical
Thoracic most symptomatic - cord compression
Cervical highest rate of mortality
Most in anterior and middle columns, rarely posterior.
What are the spinal red flags?
Weight loss, night pain and fevers
Hx and Examine
Breast lumps, cough, urinary problems.
What is a reflex? Definition
A reflex is an involuntary response to a stimulus via a reflex arc
What is difference between spinal shock and neurogenic shock?
Spinal shock (Whytt 1750) loss of sensation and motor paralysis with initial loss but gradual recovery of reflexes following a SCI. 4 phases. Polysynaptic reflexes return in phase 2
Disruption of autonomic pathways within spinal cord leading to hypotension and bradycardia. (Loss of sympathetics and unopposed vagal tone)
What is the classification used for C2 cervical spine injuries? - Hangman’s
Levine and Edwards
Type I - 3mm. Signif angulation. Vertical fracture line. C2/3 disc and PLL disrupted. Unstable. 5mm
SURGERY OR PROLONGED TRACTION.
Type IIa no horizontal displacement. Horizontal fracture line. significant angulation.
AVOID TRACTION. REDUCE IN HYOEREXTENSION THEN HALO 6-12
Type III - type I with associated bilateral C2/3 facet dislocation. Rare
SURGICAL REDUCTION OF FACET DISLOCATION AND STABILISATION.
What level of change is concerning on neurophysiology testing during spine surgery?
> 50% reduction in SSEP
> 75% reduction in amplitude for MEP
Also free running EmG - burst and train response and stimulus evoked EMG - low current depolarisation (7mA) of pedicle screws concerning
4 causes of scoliosis
1) Neuromuscular -
CP, Musc dystrophy, NF, Marfan’s, Arthrogryposis, EDS
2) Congenital -
failure formation, segmentation, mixed
3) Idiopatic -
Infantile, juvenile, adolescent, Adult
4) Syndromal - Skeletal Dysplasias
Approach to Infantile Idiopathic Scoliosis
Age & Thoracic deformity Characteristic RVAD Other reasons -MRI if not idiopathic Mx - cast 5, surgery if progresses
break it down into two groups: early-onset before age 5 : late- onset after age 5
The key - if significant thoracic deformity present before 5 - real risk of subsequent cardiopulmonary compromise down the road
Characteristics -
- Males more commonly affected than females
- 3/4 convex to LEFT, unlike adolescent idiopathics where the vast majority is convex right
- In general, most curves resolve spontaneously
- Thoracic and thoracolumbar curves tend to resolve, but DOUBLE structural curves with a thoracic component have a definite progressive potential
- Initial curve size and amount of associated rotation are prognostic factors
If Mehta RVAD exceeds 20°, curve is likely to be progressive - single most important factor predicting progression
Start searching for other reasons for the deformity
- Dysraphism?
- Tethered cord?
- Syrinx?
- Congenital failure of formation or segmentation?
- Look for other visceral abnormalities
- X-rays to see if this is a congenital curve
- Then measure the RVAD
- If any suspicion that this is not an “idiopathic” curve, get an MRI!
Treatment
- Most resolve on their own
- Serial casting
(elongation derotation flexion casting) is the conservative treatment of choice - The indications for casting are unclear, but any low-weight floppy child with a big curve and an RVAD over 20° should be casted
- Casting is usually done in the OR under GA
- No point in casting past 5 years of age (growth velocity has plateaued). Can be braced after this
- Surgery when serial casting has failed to halt progression -– requires anterior discectomy over four or five apical segments, then growing rod posteriorly
Response to bracing for Juvenile Idiopathic scoliosis
Treatment
- Curves less than 25° are observed
- Curves that progress beyond 25° are braced (Milwaukee brace)
Curves greater than 45° at the beginning of brace treatment tend to require surgery eventually
- Curves greater than 35° at the beginning of brace treatment have a 50% chance of requiring surgery
Milwaukee brace
- Patients with curves less than 35° and RVAD of less than 20° tend to do well with brace
- Patients with curves greater than 45° and RVAD of greater than 20° tend to do poorly with brace
- Patients between 35 and 45° were unpredictable
Risks of progression in Adolescent Idiopathic scoliosis
Curve Progression – 4 Growth Factors, 2 Curve Factors
- The younger the patient at diagnosis, the higher the risk of progression
- Presentation prior to menarche portends a higher risk of progression
- The lower the Risser grade at curve detection, the higher the risk of progression
- Females with comparable curves to males have 10 times the risk of progression
- Double curves have a greater tendency to progress than single
- The larger the curve at detection, the higher the risk of progression
Formula for shortening with scoliosis surgery
A basic formula: cm of shortening = 0.07 x number of segments fused x number of years of growth remaining
So if you were going to fuse 8 segments in a 7 year old who has 7 more years to grow, the predicted cm of shortening would be 0.07 x 8 x 7 = 3.92 cm
Bracing indications in Idiopathic adolescent scoliosis
Bracing Indications – In principle, works on growing spine (don’t use if almost finished growing)
- Patients should be skeletally immature –- R0-1, and premenarchal or postmenarchal by < 1 year
- The 30-40o curve should have bracing started immediately
- The 20-30o curve can be watched, and bracing started if there is progression of 5o
- Curves less than 20o should be watched for progression
- Basically, you have to be R0-1 and premenarchal or just recently postmenarchal even to be considered
- Do not send away the 30-40o curve for observation –- they need bracing NOW.
Location classification of Scoliosis
⇨ CERVICAL (C2-C6) ⇨ CERVICOTHORACIC (C7-T1) ⇨ THORACIC (T2-T11/12 Disc) ⇨ THORACOLUMBAR (T12-L1) ⇨ LUMBAR (L1/2 Disc-L4)
Age classification of Idiopathic scoliosis
to complete
Characteristics of Infantile IS
Rare Most Left sided Increased incidence of neural axis abnormalities Impaired respiratory function main issue Low rate of progression - 10%
Characteristics of Juvenile IS
Second most common
Higher incidence of neural axis abnormalities
Most Right sided
High rate of progression - 95%
