Spondyloytic Spondylolisthesis

Question 1

how to describe the segments involved

Answer 1

-Always describe the slip of the segment above w respect to the segment below

Question 2

4 types

Answer 2

1. dysplastic- born w abnormal neural arch
2. Isthmic
3. Degenerative- no pars defect
4. Traumatic- fracture of neural arch not involving pars

Question 3

3 types of isthmic

Answer 3

a) pars defect
b) elongated pars
c) Acute pars fracture (rare)

Question 4

why does spondylolytic spondylolisthesis usually happen

Answer 4

• stress fracture of pars interarticularis due to upright human posture
• not found before 5

Question 5

what is the most common segment affected

Answer 5

90% at L5

Question 6

5 grading percentages

Answer 6

1- <25%
2- 25-50%
3- 51-75%
4- 76-100%
5- >100%

Question 7

what is the inverted napolean hat sign

Answer 7

with grade 2s and above in ap view the L5 vert may slip infront of sacral base and thus wont see some disk space

Question 8

what are some clinical signs and symptoms of this

Answer 8

• may have palpable step defect
• may have hyper lordosis
• tight hams
• may have lumbosaccral pain when standing or slow walk

Question 9

how do you know if it is unstable

Answer 9

flex and extension study

if it slips >4.5mm more in flex or ext compared to neurtal it is deemed unstable