Isthmic Spondylolisthesis

Question 1

What is the cause of adult isthmic spondylolisthesis?

Answer 1

Defect in the pars interarticularis

Question 2

What is the most common location for adult isthmic spondylolisthesis?

Answer 2

L5/S1- 82% (compress L5 nerve root; ankle dorsiflexion and EHL)
L4/L5- 11%

Question 3

What is the treatment for L5/S1 adult isthmic spondylolisthesis?

Answer 3

1) conservative with NSAIDs
2) if low grade and intractable pain for 6 months; L5/S1 decompression and fusion
3) if high grade and intractable pain for 6 months; L4/S1 decompression and fusion
Risks of L5 neuropathy d/t stretching from reduction